JP2011185944A - Rolling bearing unit with load measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure allowing measurement of a load applied between an outer ring 3 and a hub 4 without using a component dedicated for measuring the load such as a displacement sensor. <P>SOLUTION: An encoder 12 the characteristics of which are changed alternately at equal intervals in a circumferential direction is supported and fixed onto a hub 4 concentrically with the hub 4. A sensing part of a sensor 13 supported on the outer ring 3 is positioned in close vicinity to a surface to be sensed of the encoder 12 to face thereto. Width dimensions of first and second parts to be sensed provided onto the surface to be sensed are changed continuously in a direction along which a load to be sensed is applied. Since the changing pattern of the output signal of the sensor 13 is changed according to change of the load, the load is determined by observing this pattern. The output signal is also used to determine a rotation speed of the hub 4 and also to control ABS or TCS. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The rolling bearing unit with a load measuring device according to the present invention, for example, supports a vehicle (automobile) wheel rotatably with respect to a suspension device, and measures the magnitude of a load applied to the wheel to stably operate the vehicle. Use to secure. Alternatively, it is incorporated in a rolling bearing unit for supporting the spindles of various machine tools, is used for measuring the load applied to the spindle and adjusting the feed rate of the tool appropriately.

  For example, a rolling bearing unit is used to rotatably support a vehicle wheel with respect to a suspension device. In order to ensure the running stability of the vehicle, a running state stabilizing device for the vehicle such as an antilock brake system (ABS) or a traction control system (TCS) is widely used. According to these running state stabilizing devices such as ABS and TCS, the running state of the vehicle at the time of braking or acceleration can be stabilized, but in order to ensure this stability even under more severe conditions, the vehicle It is necessary to control the brakes and the engine by incorporating more information that affects the running stability of the vehicle.

  That is, in the case of the conventional running state stabilizing device such as ABS or TCS, since so-called feedback control is performed to detect the slip between the tire and the road surface and control the brake and the engine, the brake and engine Control is delayed for a moment. In other words, in order to improve performance under severe conditions, the so-called feed-forward control prevents slippage between the tire and the road surface, or the so-called brake one-side effect where the braking forces of the left and right wheels are extremely different. Cannot be prevented. Furthermore, it is impossible to prevent the running stability of a truck or the like from being deteriorated based on the poor loading state.

  In order to cope with such a problem, in order to perform the feedforward control or the like, one of a radial load and an axial load applied to the wheel is applied to the rolling bearing unit for supporting the wheel with respect to the suspension device. Or it is possible to incorporate a load measuring device for measuring both. Conventionally, what was described in patent documents 1-4 is known as a rolling bearing unit for wheel support with a load measuring device which can be used in such a case.

  Of these, Patent Document 1 describes a rolling bearing unit with a load measuring device capable of measuring a radial load. In the case of the first example of the conventional structure, the outer ring and the hub are measured by measuring the radial displacement between the outer ring that does not rotate and the hub that rotates on the inner diameter side of the outer ring by a non-contact displacement sensor. The radial load applied between and is calculated. The obtained radial load is used not only to properly control the ABS but also to inform the driver of a bad loading condition.

  Patent document 2 describes a structure for measuring an axial load applied to a rolling bearing unit. In the case of the second example of the conventional structure described in Patent Document 2, bolts for connecting the fixed side flange to the knuckle are screwed at a plurality of positions on the inner side surface of the fixed side flange provided on the outer peripheral surface of the outer ring. Each load sensor is attached to a portion surrounding the screw hole. Each load sensor is clamped between the outer surface of the knuckle and the inner surface of the fixed flange in a state where the outer ring is supported and fixed to the knuckle. In the case of the load measuring device for the rolling bearing unit of the second example having such a conventional structure, the axial load applied between the wheel and the knuckle is measured by the load sensors.

  Further, in Patent Document 3, the displacement sensor unit supported at four positions in the circumferential direction of the outer ring and the L-shaped detection ring that is externally fitted and fixed to the hub are used to detect the above-described outer ring at the four positions. A structure is described in which the displacement of the hub in the radial direction and the thrust direction is detected, and the direction and magnitude of the load applied to the hub are determined based on the detected values of the respective parts.

  Furthermore, in Patent Document 4, a strain gauge for detecting dynamic strain is provided in a member corresponding to an outer ring whose rigidity is partially reduced, and the revolution speed of the rolling element is determined from the passing frequency of the rolling element detected by the strain gauge. A method for determining the axial load applied to the rolling bearing from the revolution speed is described.

  In the case of the first example of the conventional structure described in Patent Document 1, the load applied to the rolling bearing unit is measured by measuring the displacement in the radial direction between the outer ring and the hub using a displacement sensor. However, since the displacement amount in the radial direction is small, it is necessary to use a highly accurate displacement sensor in order to obtain this load with high accuracy. Since high-precision non-contact sensors are expensive, it is inevitable that the cost of the entire rolling bearing unit with a load measuring device increases.

In the second example of the conventional structure described in Patent Document 2, it is necessary to provide as many load sensors as the bolts for supporting and fixing the outer ring to the knuckle. For this reason, coupled with the fact that the load sensor itself is expensive, it is inevitable that the cost of the entire load measuring device of the rolling bearing unit is considerably increased. In addition, the structure described in Patent Document 3 is more expensive than the structure described in Patent Document 1 because sensors are installed at four positions in the circumferential direction of the outer ring. Furthermore, the method described in Patent Document 4 needs to reduce the rigidity of a part of the outer ring equivalent member, and it may be difficult to ensure the durability of the outer ring equivalent member.
Moreover, the structure and method described in any of Patent Documents 1 to 4 are provided with a dedicated mechanism for measuring the load applied to the rolling bearing unit. For this reason, an increase in cost and weight is inevitable.

  As a technique related to the present invention, Patent Document 5 uses an encoder in which N poles and S poles are alternately arranged on the detected surface, thereby detecting the center runout of the inner ring that supports the encoder. The structure is described. However, Patent Document 5 does not describe a technique for obtaining a load applied to a rolling bearing unit using the encoder, even if a description suggesting such a technique is included.

JP 2001-21577 A Japanese Patent Laid-Open No. 3-209016 Japanese Patent Laid-Open No. 2004-3918 Japanese Patent Publication No.62-3365 JP 2004-77159 A

  The present invention has been invented in order to realize a rolling bearing unit with a load measuring device that can be configured in a small size and light weight and that is required to apply a load applied to the rolling bearing unit.

Each of the rolling bearing units with a load measuring device according to the present invention includes a rolling bearing unit and a load measuring device.
Of these, the rolling bearing unit is present on a stationary bearing ring that does not rotate even in use, a rotating bearing ring that rotates in use, and circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. A plurality of rolling elements provided between the stationary-side track and the rotating-side track are provided.
In addition, the load measuring device rotates together with the rotation side raceway or the rotation side raceway to a part of a member that is coupled and fixed to the rotation side raceway or the rotation side raceway. An encoder that is supported concentrically with the member to be detected and whose characteristics of the surface to be detected are alternately changed with respect to the circumferential direction, and a portion that does not rotate in a state where the detection portion faces the surface to be detected (for example, the stationary side A sensor that is supported by a bearing ring or a suspension or a part of a housing that supports and fixes the stationary-side bearing ring, and that changes an output signal in response to a change in characteristics of the detected surface, and an output signal of the sensor And a calculator for calculating a load acting between the stationary side raceway and the rotation side raceway.
Further, the pitch at which the characteristics of the surface to be detected change with respect to the circumferential direction changes continuously according to the acting direction of the load to be detected (for example, over the acting direction).
The computing unit has a function of calculating the load based on a pattern in which the output signal of the sensor changes.

Especially in the case of the invention described in claim 1, the load to be detected, a radial load acting in the radial direction between the stationary side raceway ring and the rotary bearing ring.
Then, the sensed surface is an axial side of the encoder, to the detected face, a plurality of the combination unit for the detection consisting of individualized portions of each pair of characteristic different from the other portion, the circle They are arranged at regular intervals in the circumferential direction.
The distance in the circumferential direction of the individualized portions each other in pairs constituting the respective detection target for the combination unit, in all of the detection combining unit continuously varies in the same direction with respect to the radial direction Yes .

In the case of the invention described with respect thereto to claim 2, the load to be detected is an axial load acting in the axial direction between the stationary side raceway ring and the rotary bearing ring.
Then, the sensed surface is the peripheral surface of the encoder, to the detected face, a plurality of the combination unit for the detection consisting of individualized portions of each pair have different characteristics from the other portions, the circumferential They are arranged at regular intervals in the direction.
The distance in the circumferential direction of the individualized portions each other in pairs constituting the respective detection target for the combination unit, in all of the detection combining unit continuously varies in the same direction with respect to the axial direction Yes .

  The rolling bearing unit with a load measuring device of the present invention configured as described above acts as follows, and a load acting between the stationary side race ring and the rotation side race ring is obtained. First, when a load is applied between the two race rings, the two race rings are relatively displaced with the elastic deformation of the stationary side, the rotary side races and the rolling elements. As a result, the detected surface of the encoder supported by a part of the rotation side raceway or a member that is coupled and fixed to the rotation side raceway and rotates together with the rotation side raceway, and the stationary side raceway or the suspension device The positional relationship with the detection unit of the sensor supported by a part that does not rotate, such as a part, changes.

The pitch at which the characteristic of the detected surface of the encoder changes in the circumferential direction changes continuously over the direction of the load to be detected. When displaced, the pattern (cycle or magnitude of change ) in which the output signal of the sensor changes with the rotation of the rotating raceway changes. Since there is a correlation between the degree of change of the pattern and the magnitude of the load, the magnitude of the load can be obtained based on this pattern.
In particular, in the case of the present invention, the output signal of the sensor whose detection unit faces the detection target surface of the encoder changes at the moment when it faces each individualization portion. It changes with the change in the radial position (in the case of the invention described in claim 1) or the axial position (in the case of the invention described in claim 2) of the part where the detection part of the sensor faces.

  The combination of the encoder and the sensor is also necessary for detecting the rotational speed of the rotating raceway in order to control the ABS and TCS (when implemented with respect to a wheel bearing rolling bearing unit). Even when it is performed on a machine tool, it is necessary for detecting the rotational speed of the spindle. The rolling bearing unit with a load measuring device of the present invention can be configured so that the above load can be obtained by devising the structure necessary for detecting such rotational speed, and a new part is added to the rolling bearing unit portion. Eliminates the need for incorporation. For this reason, the structure for calculating | requiring the load added to this rolling bearing unit can be comprised small and lightweight.

Sectional drawing which shows the 1st example of the reference example relevant to this invention . The figure which took out the encoder main body and was seen from the right side of FIG. The figure similar to FIG. 2 which shows the scanning part of the to-be-detected surface of the encoder by the detection part of a sensor. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of radial load. The diagram which shows one example of the relationship between radial displacement of an outer ring | wheel and a hub, and radial load. The perspective view and front view which show two examples of the encoder integrated in the 2nd example of the reference example relevant to this invention . Sectional drawing which shows the 3rd example. The principal part perspective view which shows three examples of the encoder integrated in the 1st example of embodiment of this invention . The figure which looked at the to-be-detected surface of the encoder from the axial direction which shows the scanning part of the to-be-detected surface of the encoder by the detection part of a sensor. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of radial load. Sectional drawing which shows the 4th example of the reference example relevant to this invention . The perspective view which shows the raw material and assembly state of an encoder which are incorporated in the fourth example . The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. Sectional drawing which shows the 5th example of the reference example relevant to this invention . The perspective view which shows the raw material and assembly state of the encoder which are integrated in the 2nd example of embodiment of this invention . Sectional drawing which shows the 6th example of the reference example relevant to this invention . The fragmentary perspective view of the encoder incorporated in the 6th example . The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. Sectional drawing which shows the 7th example of the reference example relevant to this invention . The perspective view of the encoder incorporated in the 7th example . The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. Sectional drawing which shows the 8th example of the reference example relevant to this invention . The front view of the encoder incorporated in the 8th example . The fragmentary sectional view which shows the 9th example of the reference example relevant to this invention . Sectional drawing which shows the 10th example . The schematic sectional drawing which shows the assembly | attachment state between a suspension apparatus and a wheel. The diagram for demonstrating the fluctuation | variation of the output signal of the sensor accompanying a displacement. Sectional drawing which shows the 11th example of the reference example relevant to this invention . Sectional drawing which shows the 12th example . Sectional drawing which shows the 13th example . Sectional drawing which shows the 14th example . Sectional drawing which shows the 15th example . The perspective view of the encoder incorporated in the 15th example . Similarly development. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. Sectional drawing which shows the 16th example of the reference example relevant to this invention . The perspective view of the encoder incorporated in the 16th example . Similarly development. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. The 17th example of the reference example relevant to this invention is the figure seen from the partial sectional view and radial direction which show in the neutral state and the displaced state. The figure which shows this to-be-detected surface in the state seen from radial direction for demonstrating the positional relationship of the to-be-detected surface of an encoder and the detection part of a pair of sensor. The 18th example of the reference example relevant to this invention is the figure seen from the partial sectional view and radial direction which are shown in the neutral state and the displaced state. The schematic side view which shows the three examples of the shape of the to-be-detected surface provided in the outer periphery part of the disc rotor which shows the 19th example of the reference example relevant to this invention . The front view and side view which show an example of the attachment state of a sensor. Sectional drawing which shows the 20th example of the reference example relevant to this invention .

[First example of reference example related to the present invention ]
1 to 5 show a first example of a reference example related to the present invention . The rolling bearing unit with a load measuring device of the present reference example includes a wheel supporting rolling bearing unit 1 and a load measuring device 2 having a function as a rotational speed detecting device.
Of these, the wheel support rolling bearing unit 1 includes an outer ring 3, a hub 4, and a plurality of rolling elements 5, 5 as shown in FIG. 1. Of these, the outer ring 3 is a stationary-side bearing ring that is supported and fixed to the suspension device in use. The outer ring 3 has double-row outer ring raceways 6 and 6 connected to the suspension surface on the outer peripheral surface. Each has an outward flange-shaped attachment portion 7. The hub 4 is a rotating raceway that supports and fixes a wheel in use and rotates together with the wheel. The hub body 8 and the inner ring 9 are combined and fixed. Such a hub 4 includes a flange 10 for supporting and fixing a wheel to an outer peripheral end portion in the axial direction of the outer peripheral surface (an end portion on the outer side in the width direction of the vehicle body when assembled to the suspension device). Double-row inner ring raceways 11 are provided on the outer circumferential surface of the inner ring 9. A plurality of each of the rolling elements 5 and 5 are provided between the inner ring raceways 11 and 11 and the outer ring raceways 6 and 6, respectively, so that they can freely roll, and the hub 4 is provided on the inner diameter side of the outer ring 3. Is rotatably supported concentrically with the outer ring 3. In the illustrated example, a ball is used as the rolling element, but in the case of a rolling bearing unit for supporting a wheel of a heavy vehicle, a tapered roller may be used as each rolling element. The structure using balls as rolling elements can increase the amount of displacement between the outer ring and the hub compared to the structure using tapered rollers. Since they are small, they are displaced, and can be the subject of the present invention.

On the other hand, as shown in FIG. 1, the load measuring device 2 includes an encoder 12, a sensor 13, and an arithmetic unit (not shown).
Of these, the encoder 12 includes a support plate 14 and an encoder body 15. Of these, the support plate 14 is formed by bending a magnetic metal plate such as a mild steel plate so that the annular portion 16 and the cylindrical portion 17 are continuous by an inclined portion. Is an annular shape. The encoder body 15 is made of a permanent magnet such as a rubber magnet or a plastic magnet, and has an annular shape as a whole. The encoder body 15 is attached and fixed concentrically with the cylindrical portion 17 on the inner surface in the axial direction of the annular portion 16. Yes.

The permanent magnets constituting the encoder body 15 are magnetized in the axial direction, and the magnetization direction is changed alternately and at equal intervals over the circumferential direction. Therefore, N poles and S poles are alternately arranged at equal intervals on the inner side surface in the axial direction of the encoder body 15 which is a detected surface. In the case of the present reference example , the first detected portion in which the portion magnetized in the N pole and the portion magnetized in the S pole are present on the detection surface of the encoder 12 and have different characteristics from each other. And the second detected part. Of the width in the circumferential direction between the portion magnetized in the N pole and the portion magnetized in the S pole, the width of the portion magnetized in the N pole is wider toward the outside in the radial direction, The width of the magnetized portion is increased toward the inner side in the radial direction. The magnetization range of these N poles and S poles may be reversed from the illustrated case.

  The encoder 12 configured as described above is fitted on the inner end of the hub 4 in the axial direction by fitting the cylindrical portion 17 of the support plate 14 to the inner end of the inner ring 9 with an interference fit. The hub 4 is connected and fixed concentrically. In this state, the inner surface in the axial direction of the encoder body 15 is located on a virtual plane orthogonal to the central axis of the hub 4.

  On the other hand, the sensor 13 is supported and fixed to the inner end of the outer ring 3 in the axial direction via a cover 18. The cover 18 is formed into a bottomed cylindrical shape by injection molding a synthetic resin or by drawing a metal plate, and in a state of closing the inner end opening of the outer ring 3, It is fitted and fixed to the inner end of the outer ring 3. A mounting hole 20 is formed in a portion of the bottom plate portion 19 of the cover 18 that is close to the outer diameter of the bottom plate portion 19 and opposed to the detection surface of the encoder 12 so as to penetrate the bottom plate portion 19 in the axial direction. ing.

  The sensor 13 is supported and fixed to the bottom plate portion 19 in a state in which the mounting hole 20 is inserted from the inside in the axial direction to the outside. And the detection part provided in the front end surface (left-end surface of FIG. 1) of the said sensor 13 is made to oppose and adjoin with the to-be-detected surface of the said encoder 12 through the measurement clearance gap of about 0.5-2 mm. In addition, a magnetic detecting element such as a Hall element or a magnetoresistive element is provided in the detecting portion of the sensor 13 which is an active magnetic sensor. The characteristics of such a magnetic detection element change between a state facing the N pole and a state facing the S pole. Therefore, when the encoder 12 rotates together with the hub 4, the characteristics of the magnetic detection element change, and the output signal of the sensor 13 changes.

In this way, the cycle (frequency) at which the output signal of the sensor 13 changes varies according to the rotational speed of the hub 4. Specifically, the faster the rotation speed, the shorter the cycle of changing the output signal, and the higher the changing frequency. For this reason, if this output signal is sent to a controller (not shown) provided on the vehicle body side or the like, the rotational speed of the wheel rotating together with the encoder 12 can be obtained to control the ABS and TCS. This point is the same as a conventionally known technique.
In particular, in the case of this reference example , since the pattern in which the output signal changes changes based on the magnitude of the radial load acting between the hub 4 and the outer ring 3, this pattern should be observed. Thus, the radial load can be obtained. This point will be described with reference to FIGS.

First, the premise for obtaining the radial load will be described. As described in Patent Document 1 described above, the relative position in the radial direction between the outer ring 3 and the hub 4 changes according to the magnitude of the radial load applied between the outer ring 3 and the hub 4. . The reason for this is that, based on the radial load, the rolling elements 5, 5 and the rolling surfaces of the rolling elements 5, 5 are in rolling contact with the outer ring raceways 6, 6 and the inner ring raceways 11, respectively. This is because the amount of elastic deformation 11 changes. In the case of the prior art described in Patent Document 1, the radial load applied between the outer ring and the hub is obtained by directly measuring the displacement in the radial direction between the outer ring and the hub using a displacement sensor. It was. On the other hand, in the case of this reference example, the radial applied between the outer ring 3 and the hub 4 based on the pattern of change in the output signal accompanying the relative displacement between the encoder 12 and the sensor 13. The magnitude of the load is calculated. This point will be described below.

When a standard radial load (standard value) is applied between the outer ring 3 and the hub 4, the detection portion of the sensor 13 faces the center portion in the radial direction of the detection surface of the encoder 12. Assuming that In this case, the detection unit of the sensor 13 scans the central portion of the detected surface, which is indicated by a chain line α in FIG. In this radial central portion, the width in the circumferential direction of the portion magnetized in the N pole and the width in the circumferential direction of the portion magnetized in the S pole are equal to each other. As shown in FIG. 4A, the same voltage is swung on both sides around the reference voltage (for example, 0 V). That is, the period T _H when the voltage of the output signal is higher than the reference voltage and the period T _{L when} it is lower are equal to each other (T _H = T _L ). The difference ΔV _H between the maximum value of the output signal voltage and the reference voltage and the difference ΔV _L between the minimum value and the reference voltage are also equal to each other (ΔV _H = ΔV _L ).

On the other hand, when the radial load applied between the outer ring 3 and the hub 4 becomes larger than a standard value, the position of the outer ring 3 with respect to the hub 4 is shifted downward, and the detection unit of the sensor 13 Opposite to the radially inner portion of the detection surface of the encoder 12. In this case, the detection unit of the sensor 13 scans a radially inward portion of the detected surface indicated by a chain line β in FIG. In the radially inward portion, the width in the circumferential direction of the portion magnetized in the N pole is narrower than the width in the circumferential direction of the portion magnetized in the S pole. As shown in FIG. 4B, the reference voltage (for example, 0 V) is largely shifted toward the lower side. In other words, the period T _L when the voltage of the output signal is lower than the reference voltage is larger than the period T _H where the voltage T _L becomes higher (T _H <T _L ). Further, the difference ΔV _L between the minimum value of the output signal voltage and the reference voltage is also larger than the difference ΔV _H between the maximum value and the reference voltage (ΔV _L > ΔV _H ).

Further, contrary to the case described above, when the radial load applied between the outer ring 3 and the hub 4 becomes smaller than the standard value, the position of the outer ring 3 with respect to the hub 4 shifts upward, and the sensor 13 The detecting portion of the encoder 12 is opposed to a radially outward portion of the detected surface of the encoder 12. In this case, the detection unit of the sensor 13 scans a radially outward portion of the detected surface indicated by a chain line γ in FIG. In the radially outer portion, the width in the circumferential direction of the portion magnetized in the N pole is wider than the width in the circumferential direction of the portion magnetized in the S pole. As shown in (C) of FIG. 4, the reference voltage (for example, 0V) is largely swung to the higher side. That is, the period T _H when the voltage of the output signal becomes higher than the reference voltage is larger than the period T _{L when} it becomes lower (T _H > T _L ). Further, the difference ΔV _H between the maximum value of the output signal voltage and the reference voltage is also larger than the difference ΔV _L between the minimum value and the reference voltage (ΔV _H > ΔV _L ).

Therefore, by looking at the pattern of the output signal of the sensor 13, it is possible to determine the degree of deviation (radial displacement) between the central axis of the outer ring 3 and the central axis of the hub 4. Specifically, if the ratio “T _H / T _L ” between the period T _{H at} which the potential of the output signal is higher than the reference voltage and the period T _{L at which} it becomes lower is observed, the central axis of the outer ring 3 and the hub It is possible to determine the degree of deviation from the central axis of 4 (the amount of radial displacement). Or, observe the ratio “ΔV _H / ΔV _L ” between the difference ΔV _H between the maximum value of the voltage of the output signal and the reference voltage and the difference ΔV _L between the minimum value and the reference voltage. The above-described radial displacement amount can also be obtained. The relationship between these ratios “T _H / T _L ”, “ΔV _H / ΔV _L ” and the amount of radial displacement can be easily obtained because the ratio is almost linear for any ratio. And the calculated | required relationship is integrated in the software installed in the calculator (microcomputer) which is not shown in figure for calculating the said radial load.

  Further, the relationship between the radial displacement and the radial load can be obtained by calculation or experiment. When obtaining by calculation, the specifications of the rolling bearing unit 1, that is, the radius of curvature of the cross sections of the outer ring raceways 6 and 6 and the inner ring raceways 11 and 11, the number and diameter of the rolling elements 5 and 5, respectively. In addition, based on the material of the outer ring 3 and the hub 4, it is obtained based on the theory widely known in the technical field of rolling bearing units. Further, in the case of obtaining by experiment, a relative displacement amount in the radial direction between the outer ring 3 and the hub 4 is applied between the outer ring 3 and the hub 4 while applying different known radial loads. Measure. In any case, a relationship as shown in FIG. 5 is obtained with respect to the radial displacement amount and the radial load, and incorporated in the software.

Since this reference example is configured as described above, the radial load can be obtained without having to incorporate new components such as a displacement sensor in the rolling bearing unit portion. That is, the combination of the encoder 12 and the sensor 13 is also necessary for detecting the rotational speed of the hub 4 so as to control the ABS and TCS. The rolling bearing unit with a load measuring device of this reference example is a structure that obtains the above radial load by devising the structure necessary to detect such rotational speed, so the radial load applied to this rolling bearing unit is The required structure can be made small and lightweight.

Incidentally, as is clear from FIG. 4, the case of the present embodiment, the magnitude of the radial load, the period T _L of the voltage of the output signal becomes lower as the higher becomes the period T _H than the reference voltage of the sensor 13 changes . Accordingly, in order to accurately obtain the rotational speed of the hub 4 regardless of the change in the radial load, the rotational speed is calculated based on the sum of the two periods “T _H + T _L ”. This sum “T _H + T _L ” is obtained even when the portion magnetized at the N pole and the portion magnetized at the S pole are fan-shaped or reverse fan-shaped as shown in FIGS. Since the rotation speed is almost constant regardless of the direction displacement, the rotation speed can be accurately obtained.

[Second example of reference example related to the present invention ]
FIG. 6A shows a second example of a reference example related to the present invention . In the case of this reference example , the through holes 21 and 21 are formed at equal intervals in the circumferential direction in the radial intermediate portion of the annular encoder 12a. In the case of this reference example , each of the through holes 21 and 21 has an inverted fan shape (or an inverted trapezoidal shape) whose width in the circumferential direction becomes narrower toward the outer side in the radial direction of the encoder 12a. The portions 22 and 22 between the through holes 21 adjacent to each other in the circumferential direction are formed in a sector shape (or a trapezoidal shape) whose width in the circumferential direction increases toward the outer side in the radial direction. Therefore, in the case of the present reference example, the inter-portions 22 and 22 are the first detected portions , and the through-holes 21 and 21 are the second detected portions. Contrary to the above case, as shown in FIG. 6B, the widths of the through holes 21a and 21a are increased toward the outer side in the radial direction, and the widths of the intermediate portions 22a and 22a are set to the outer side in the radial direction. You can make it smaller as you go.

In any case, by combining with an appropriate sensor, the center axis of a stationary side race ring such as an outer ring that supports this sensor and the encoder 12a are supported in the same manner as in the first example of the reference example described above. The amount of displacement in the radial direction with respect to the center axis of the fixed rotating side race ring such as a hub can be obtained. And the radial load which acts between these stationary side races and rotation side races is calculated. The material constituting the encoder 12a is selected according to the type of sensor.
For example, when the sensor is an active magnetic sensor including a permanent magnet and a magnetic detection element such as a Hall element or a magnetoresistive element, the encoder 12a is made of a magnetic metal such as a steel plate. . The same applies to the case where the sensor is a passing type magnetic sensor including a permanent magnet, a pole piece, and a coil. Even in such a structure, as in the case of the first example of the reference example , the sensor 12a is changed in accordance with a change in the radial position of a portion of the detection surface of the encoder 12a facing the detection unit of the sensor. Output signal changes. When a magnetic sensor is used, a fan-shaped or inverted fan-shaped concave portion or convex portion can be formed on the detection surface of the encoder instead of the through hole. In the case of an encoder made of a permanent magnet having N poles and S poles arranged on the surface to be detected, the load detection accuracy may deteriorate as the magnetic flux intensity becomes non-uniform. If an encoder having a through hole, or a recess or projection is used, such a problem does not occur, and it is easy to ensure the load detection accuracy.

On the other hand, when the sensor is an optical sensor, one structure of the first detected part or the second detected part formed on the detected surface of the encoder 12a is limited to a through hole. In this case, the material constituting the encoder 12a may be any material that blocks light. When an optical sensor is used, a cycle in which the output signal of the sensor changes in accordance with a change in the radial position of a portion of the detection surface of the encoder 12a that faces the detection unit of the sensor. Change (the magnitude of change does not change).
Since the structure and operation of the parts other than the encoder 12a are the same as those of the first example of the reference example described above, illustration and description regarding the equivalent parts are omitted.

[Third example of reference example related to the present invention ]
FIG. 7 shows a third example of the reference example related to the present invention . In the case of this reference example , the encoder 12b is externally fitted and fixed between the rolling elements 5 and 5 arranged in a double row at the axially intermediate portion of the hub 4a. The encoder 12b includes a support plate 14a that is L-shaped in cross section and formed in an annular shape as a whole. Then, the permanent magnet encoder body 15 as shown in FIGS. 2 and 3 is attached to one side surface in the axial direction of the annular portion 23 of the support plate 14a, or the annular portion 23 described above with reference to FIG. By forming the through-holes 21 and 21a or the concave holes as shown in FIG. 1, the ring portion 23 itself has a function as an encoder.

The sensor 13a combined with such an encoder 12b is inserted into a mounting hole 20a formed in a portion between the double-row outer ring raceways 6 and 6 at an intermediate portion in the axial direction of the outer ring 3 from the radially outer side of the outer ring 3. It is inserted toward the direction. The detector provided on the side surface in the axial direction at the front end of the sensor 13a is close to the detected surface of the encoder body 15 attached to the axial side surface of the annular portion 23 or the side surface of the annular portion 23 itself. I am letting.
Regarding the difference between the central axis of the hub 4a and the central axis of the outer ring 3 based on the output signal pattern of the sensor 13a, and the radial load acting between the hub 4a and the outer ring 3 is obtained from this deviation. Is the same as the first example of the reference example described above or the second example of the reference example , and therefore, a duplicate description is omitted.

[ First example of embodiment]
8 to 10 show a first example of an embodiment of the present invention corresponding to claim 1 . In the case of this example, a plurality of detection combination portions 24, 24 are arranged at equal intervals in the circumferential direction on the side surface in the axial direction of the encoder 12c, which is the detection surface. Each of these combination parts for detection 24, 24 is composed of a pair of individualized portions 25, 25 each having a different characteristic from the other portions. Such individualized portions 25, 25 include slit-like long holes as shown in FIG. 8A, concave holes as shown in FIG. 8B, and bank-like shapes as shown in FIG. Can be used. Regardless of the individualization portions 25, 25, the distance between the pair of individualization portions 25, 25 constituting the detected combination portions 24, 24 in the circumferential direction is the total. The detected combination parts 24 and 24 are continuously changed in the same direction with respect to the radial direction. In the illustrated example, the interval in the circumferential direction between the pair of individualized portions 25, 25 constituting each detected combination portion 24, 24 increases toward the outer side in the radial direction of the encoder 12c. The intervals in the circumferential direction between the individualized portions 25, 25 constituting each of the detected combination portions 24, 24 that are adjacent to each other are inclined so as to become smaller toward the outside in the radial direction of the encoder 12c.

As shown in FIG. 10, the output signal of the sensor having the detection portion opposed to the detection surface of the encoder 12c as described above changes at the moment of facing the individualization portions 25, 25. The changing interval (cycle) changes with the change in the radial position of the portion of the sensor facing the detecting portion.
For example, when a standard radial load (standard value) is applied between a stationary-side raceway such as an outer ring and a rotation-side raceway such as a hub, the detection unit of the sensor is shown in FIG. The center portion of the detection surface shown in FIG. In this case, the output signal of the sensor changes as shown in FIG.
On the other hand, when the radial load applied between the stationary side raceway and the rotation side raceway becomes larger than the standard value, the detection unit of the sensor is shown by a chain line β in FIGS. Then, the radially inward portion of the detected surface is scanned. In this case, the output signal of the sensor changes as shown in FIG.
Further, when the radial load applied between the stationary side raceway and the rotation side raceway becomes smaller than the standard value, the detection unit of the sensor, for example, the above-mentioned covered line indicated by a chain line γ in FIGS. Scan a radially outward portion of the detection surface. In this case, the output signal of the sensor changes as shown in FIG.
Therefore, also in this example, when the output signal pattern (change interval) of the sensor is seen, the center axis of the stationary side raceway and the center axis of the rotation side raceway are displaced (in the radial direction). The amount of displacement) can be obtained, and the radial load applied between these two races can be obtained from the degree of deviation.

[ Fourth Reference Example Related to the Present Invention ]
FIGS. 11-13 has shown the 4th example of the reference example relevant to this invention . In the case of this reference example , an encoder 12d is externally fitted and fixed to a portion between the rolling elements 5 and 5 arranged in a double row at the intermediate portion in the axial direction of the hub 4a. The encoder 12d is configured as shown in FIG. 12B by rounding a strip-shaped material as shown in FIG. 12A, and is similarly cylindrical on the outer peripheral surface of the cylindrical support plate 14b. An encoder body 15b is attached and fixed over the entire circumference.

  The encoder body 15b is made of a permanent magnet such as a rubber magnet or a plastic magnet, and is magnetized in the radial direction. The magnetization direction is changed alternately and at equal intervals over the circumferential direction. Therefore, N poles and S poles are alternately arranged at equal intervals on the outer peripheral surface of the encoder body 15b, which is the detected surface. Among these, the width in the circumferential direction of the portion magnetized to the N pole that is the first detected portion is wide at one end in the axial direction of the encoder body 15b and narrow at the other end. On the other hand, the width in the circumferential direction of the portion magnetized by the S pole that is the second detected portion is narrow at one end in the axial direction of the encoder body 15b and wide at the other end.

  The sensor 13b combined with such an encoder 12d is inserted into a mounting hole 20a formed in a portion between the double-row outer ring raceways 6 and 6 at an intermediate portion in the axial direction of the outer ring 3 from the radially outer side of the outer ring 3. It is inserted toward the direction. And the detection part provided in the front end surface of the said sensor 13b is made to adjoin and oppose the outer peripheral surface of the said encoder main body 15b.

In the case of this reference example having the above-described configuration, when the relative position between the outer ring 3 and the hub 4a is shifted in the axial direction due to the variation of the axial load applied between the outer ring 3 and the hub 4a, The axial position of the portion of the outer peripheral surface of the encoder body 15b facing the detection portion of the sensor 13b changes. As a result, as in the case of the first example of the reference example described above, the pattern in which the output signal of the sensor 13b changes as shown in FIG. The relationship between the pattern in which the output signal of the sensor 13b changes as shown in FIG. 13 and the magnitude of the axial load applied between the outer ring 3 and the hub 4a is also the radial in the first example of the reference example described above. Similar to the relationship between the load and the change pattern of the output signal, it can be obtained by calculation or experiment. Therefore, the magnitude of the axial load can be obtained by observing the change pattern of the output signal.

[ Fifth example of reference example related to the present invention ]
FIG. 14 shows a fifth example of the reference example related to the present invention . In the case of this reference example , the encoder 12e is fitted and fixed to the inner end of the hub 4a in the axial direction. The encoder 12e includes a support plate 14c. And the permanent magnet encoder which alternately arrange | positioned the north-pole and the south pole on the inner peripheral surface of the cylindrical part 26 of this support plate 14c in the state magnetized in the fan-shaped or trapezoid range, respectively. By attaching a main body or forming a fan-shaped or trapezoidal through hole in the cylindrical portion 26, the cylindrical portion 26 itself has a function as an encoder. And the detection part of the sensor 13c supported and fixed to the cover 18a fixed to the inner end opening part of the outer ring 3 is made to face the inner peripheral surface of the encoder 12e that is the detection surface.
Also in the case of this reference example , the magnitude of the axial load acting between the outer ring 3 and the hub 4a can be obtained by observing the change pattern of the output signal of the sensor 13c.

[ Second Example of Embodiment]
FIG. 15 shows a second example of the embodiment of the invention corresponding to claim 2 . In this example, the structure of the first example of the embodiment shown in FIGS. 8 to 10 is applied to obtain the magnitude of the axial load. That is, in the case of this example, a plurality of detection combination parts 24, 24 are wound at equal intervals on the outer peripheral surface (or inner peripheral surface) of the cylindrical encoder 12f, which is the detection surface, in the circumferential direction. It is arranged. Each of these combination parts for detection 24, 24 is composed of a pair of individualized portions 25, 25 each having a different characteristic from the other portions. In the case of this example, the individualized portions 25 and 25 as described above are slit-like long holes.

The encoder 12f having such individualized portions 25, 25 is formed by rounding a strip-shaped magnetic metal plate in which the long holes are punched and formed in advance as shown in FIG. It is made by butt welding each other. In addition, as each said individualization part 25 and 25, the above-mentioned concave hole as shown to (B) of FIG. 8 and the bank-like convex part as shown to (C) are also employable. Also in the case of this example, as in the case of the first example of the above-described embodiment, the distance between the pair of individualization portions 25 and 25 constituting the respective detected combination portions 24 and 24 in the circumferential direction. Is continuously changed in the same direction with respect to the axial direction in all the combination parts for detection 24, 24. That is, the interval in the circumferential direction between the pair of individualizing portions 25, 25 constituting each detected combination portion 24, 24 becomes smaller at one end in the axial direction of the encoder 12f (lower right end in FIG. 15). The interval in the circumferential direction between the individualized portions 25, 25 that constitute each of the detected combination portions 24, 24 adjacent in the circumferential direction is the other axial end of the encoder 12f (the upper left end in FIG. 15). It is inclined in the direction of decreasing.

The output signal of the sensor having the detection unit opposed to the outer peripheral surface (or inner peripheral surface) that is the detection surface of the encoder 12f as described above is the same as in the case of the first example of the above-described embodiment. As shown in FIG. 10, it changes at the moment of facing the individualized portions 25, 25. The changing interval (cycle) changes with the change in the axial position of the portion of the sensor facing the detecting portion. Therefore, also in this example, by looking at the pattern of the output signal of the sensor, the degree to which the stationary side raceway and the rotary side raceway are displaced in the axial direction (axial displacement amount) is obtained. Thus, the axial load applied between the two races can be determined. The method for obtaining the load from the pattern of the output signal of the sensor is the same as that in the first example of the embodiment except that the load to be obtained is changed from the radial load to the axial load .

[ Sixth Reference Example Related to the Present Invention ]
16-18 has shown the 6th example of the reference example relevant to this invention . This reference example shows a case where a structure related to the present invention is implemented in a wheel bearing rolling bearing unit 1a for driving wheels. In consideration of incorporation into a heavy vehicle, tapered rollers are used as the rolling elements 5a and 5a. In the case of this reference example , an encoder 12g as shown in FIG. 17 is externally fitted and fixed to a portion between the double row inner ring raceways 11a and 11a at an intermediate portion in the axial direction of the hub 4b. The encoder 12g is made of a magnetic metal material in an annular shape, and has convex portions 27 and 27 as first detected portions and concave portions 28 and 28 as second detected portions on an outer peripheral surface. These are formed alternately at equal intervals in the circumferential direction.

In the case of this reference example having the above-described configuration, the outer ring 3a is caused by the variation in the axial load applied between the outer ring 3a having the double-row outer ring raceways 6a, 6a formed on the inner peripheral surface and the hub 4b. When the relative position between the hub 4b and the hub 4b deviates in the axial direction, the position in the axial direction of the portion of the outer peripheral surface of the encoder 12g facing the detection portion of the sensor 13d supported on the intermediate portion in the axial direction of the outer ring 3a changes. . As a result, as in the case of the fourth example of the reference example described above, the pattern (duty ratio) in which the output signal of the sensor 13d changes changes as shown in FIG. The relationship between the pattern in which the output signal of the sensor 13d changes as shown in FIG. 18 and the magnitude of the axial load applied between the outer ring 3a and the hub 4b is the same as in the fourth example of the reference example described above. It can be obtained by calculation or experiment. Therefore, the magnitude of the axial load can be obtained by observing the change pattern of the output signal.
In addition, as in this reference example , a structure in which trapezoidal or inverted trapezoidal concave and convex portions are alternately arranged in the circumferential direction is applied to an encoder in which the detected surface is formed on the side surface in the axial direction, to a rolling bearing unit. It can also be used to measure the applied radial load.

[ Seventh example of a reference example related to the present invention ]
FIGS. 19-21 has shown the 7th example of the reference example relevant to this invention . This reference example is based on the structure of the sixth example of the reference example described above, and the shape of the convex portions 27a, 27a and the concave portions 28a, 28a formed on the outer peripheral surface of the encoder 12h that is fitted and fixed to the intermediate portion of the hub 4b. Is used to stabilize the output signal of the sensor 13d. That is, in the case of this reference example, the width dimension in the circumferential direction of the encoder 12h does not change in the axial direction of the encoder 12h at both axial ends of the convex portions 27a and 27a and the concave portions 28a and 28a. , Parallel portions 29a, 29b, 30a, 30b. Therefore, the pitch at which the characteristic of the outer peripheral surface, which is the detected surface of the encoder 12h, changes in the circumferential direction varies depending on the axial position at the axial intermediate portion of the outer peripheral surface, but the axial direction at both axial end portions. Does not change regardless of position.

In the case of this reference example, the reason why the output signal of the sensor 13d can be stabilized by providing the parallel portions 29a, 29b, 30a, and 30b is as follows. As described above, by using an encoder made of a magnetic material and having a concavo-convex portion on the surface to be detected, the pitch of the characteristic change of the surface to be detected can be made higher than that of an encoder made of a permanent magnet. However, in the case of the structure of the sixth example of the reference example described above, if the interval between the concave portion and the convex portion is shortened in order to shorten the pitch of the characteristic change, the sensor detecting portion is adjusted to the width of the detected surface of the encoder. In a state of facing the vicinity of both ends in the direction (both ends in the axial direction), the flow of magnetic flux flowing between the detection unit and the surface to be detected becomes unstable, and the output of the sensor tends to become unstable. For example, in the encoder 12g shown in FIG. 17, when the pitch between the convex portions 27 and 27 and the concave portions 28 and 28 is shortened, the bases of the trapezoidal convex portions 27 and 27 adjacent in the circumferential direction are close to each other. In particular, in order to enable detection of the rotational speed of the hub 4b even when the encoder 12g and the sensor 13d are largely displaced in the axial direction, the relative displacement amount in the axial direction allowed between the encoder 12g and the sensor 13d is set. In order to ensure, when the height of the trapezoidal shape is increased, the bottoms of the trapezoidal convex portions 27 and 27 adjacent to each other in the circumferential direction become prominent as described above.

On the other hand, in the case of this reference example , the bases of the trapezoidal convex portions 27a and 27a adjacent in the circumferential direction are excessively close to each other with the provision of the parallel portions 29a, 29b, 30a and 30b. Can be prevented. Even when the detection portion of the sensor 13d faces the portion corresponding to the bottom of the convex portions 27a and 27a at the axial end of the outer peripheral surface of the encoder 12h, the detection portion of the sensor 13d and the encoder 12h It is possible to stabilize the output of the sensor 13d by stabilizing the flow of magnetic flux flowing between the surface to be detected. Further, even if the axial displacement between the hub 4b and the outer ring 3a is slightly increased, the rotational speed of the hub 4b can be detected by the sensor 13d.

In addition, although the shape of the both sides of the circumferential direction of each said parallel part 29a, 29b, 30a, 30b is made into the straight line, the shape of this part does not necessarily need to be a straight line. For example, depending on the sensitivity and sensitivity range (spot diameter) of the sensor 13d, the sensor 13d may be slightly inclined with respect to the axial direction, or may have an arc shape with a large curvature radius.
The structure of the sensor 13d combined with the encoder 12h is not particularly limited as long as a permanent magnet is incorporated. That is, even a so-called passive type in which a coil is wound around a pole piece that guides the flow of magnetic flux from the permanent magnet is incorporated with a magnetic detection element that changes its characteristics in accordance with the magnetic flux density. The so-called active type can also be used. However, as shown in FIG. 21, the convex portions 27a and 27a and the concave portion 28a present on the outer peripheral surface of the encoder 12h in a state where the detection portion of the sensor 13d faces the intermediate portion in the axial direction of the encoder 12h. , 28a, it is necessary to sense the ratio of the length dimension in the rotation direction, and the smaller spot diameter of the sensor 13d is preferable from the viewpoint of obtaining this ratio with high accuracy.
Since the structure and operation of the other parts are the same as in the sixth example of the reference example described above, a duplicate description is omitted.

[ Eighth example of reference example related to the present invention ]
22 to 23 show an eighth example of the reference example related to the present invention . In this reference example , by devising the shape of the encoder shown in FIG. 6A, the detection portion of the sensor 13e faces the outer diameter portion or the inner diameter portion of the detected surface of the encoder. Even in this case, the output of the sensor 13e is stabilized. That is, in the case of this reference example , the non-changing portions 31a, 31b, and the outer diameter side both end portions of the through holes 21b, 21b and the intermediate portions 22b, 22b formed in the encoder 12i made of a magnetic metal plate, 32a and 32b are provided. Both circumferential edges of these non-change parts 31a, 31b, 32a, 32b exist in the diameter direction of the encoder 12i. Accordingly, in each of the non-changing portions 31a, 31b, 32a, and 32b, the pitch of the characteristic change with respect to the rotational direction of the axially inner side surface of the encoder 12i that is the detected surface does not change with respect to the radial direction.
In the case of this reference example , the point of measuring the radial load is the same as that of the second example of the reference example shown in FIG. 6, and the output of the sensor 13e is stabilized by stabilizing the flow of magnetic flux. Since this is the same as the seventh example of the reference example described above, a duplicate description is omitted.

[ Ninth example of reference example related to the present invention ]
FIG. 24 shows a ninth example of the reference example related to the invention . In the case of this reference example, the detection parts of the sensors 13f, 13g, and 13h are opposed to three positions at equal intervals in the circumferential direction on the outer peripheral surface of the encoder 12j that is the detection surface. These sensors 13f, 13g, and 13h allow the rotational speed of the hub 4a (for example, see FIG. 11), the axial load applied between the hub 4a and the outer ring 3 (for example, see FIG. 11), and the hub 4a. The moment load applied between the outer ring 3 and the outer ring 3 can be measured. The moment load obtained by this reference example is a moment around an imaginary axis perpendicular to the central axes of the hub 4a and the outer ring 3.

In the case of this reference example , not only the axial load applied between the hub 4a and the outer ring 3, but also the moment load applied between the hub 4a and the outer ring 3 can be measured. That is, as a result of the moment load being applied between the hub 4a and the outer ring 3, if the center axis of the hub 4a and the center axis of the outer ring 3 are shifted, the axial direction generated between the hub 4a and the outer ring 3 is generated. Is different for each portion where the detection units of the sensors 13f, 13g, and 13h face each other. Then, depending on the direction of the moment load, the patterns in which the output signals of these sensors 13f, 13g, 13h are different (the magnitude relationship of the output signals of these sensors 13f, 13g, 13h) are different. Further, as the moment load increases, the difference between the output signals of the sensors 13f, 13g, and 13h increases. Therefore, the relationship between the magnitude relationship of the output signals of these sensors 13f, 13g, and 13h and the action direction and magnitude of the moment load is obtained in advance by calculation or experiment, and is included in the calculation formula of software installed in the arithmetic unit. If incorporated, not only the axial load applied between the hub 4a and the outer ring 3, but also the moment load applied between the hub 4a and the outer ring 3 can be measured.

For example, the axial load applied to each part is measured based on the output signals of the sensors 13f, 13g, and 13h, and the moment load is calculated from the axial load of each part and the diameter of the encoder 12j. The axial load is obtained based on the average value of the output signals of the sensors 13f, 13g, and 13h, or the axial load obtained from the output signals of the sensors 13f, 13g, and 13h is averaged. The signals representing the axial load and moment load obtained in this way and the rotational speed of the hub 4a are sent to the controller of the ABS or TCS to stabilize the posture of the vehicle, as in the other embodiments. It is used for control.
The structure and operation of other parts are the same as, for example, the fourth example of the reference example shown in FIGS. 11 to 13 or the sixth example of the reference example shown in FIGS. The description to be omitted is omitted.

[ Tenth example of reference example related to the present invention ]
25 to 27 show a tenth example of a reference example related to the present invention . This reference example is intended to improve the measurement accuracy of the axial load acting between the outer ring 3a and the hub 4b by devising the installation position of the encoder 12g and the sensor 13A. First, the reason why a structure that takes such points into consideration is necessary will be described.
As described above, as shown in FIG. 17, the encoder is made of a magnetic material and has an uneven surface on the surface to be detected, so that the pitch of the change in the characteristics of the surface to be detected is higher than that of an encoder made of a permanent magnet. Can be made with high accuracy. However, even when a magnetic material encoder 12g in which convex portions 27, 27 and concave portions 28, 28 each having a trapezoidal shape are alternately formed on a detected surface and a magnetic detection type sensor are combined, The amount of change in the duty ratio of the output signal (the ratio between the high and low voltages of the output signal) becomes small. Thus, even when the change amount of the duty ratio is small, in order to accurately obtain the load based on the output signal of the sensor, the noise component included in the output signal should be corrected (removed). In addition, data processing using a filter such as a low-pass filter, a notch filter, or an adaptive filter is required. Of these data processing, data processing other than the adaptive filter is accompanied by a response delay, which is not preferable from the viewpoint of more accurately performing vehicle running state stabilization control. In addition, the response filter is costly instead of having no response delay.

In consideration of these matters, it is preferable to reduce the level of the noise component contained in the output signal and avoid post-processing by a filter that causes a response delay or increases the cost as much as possible. In order to relatively reduce the level of the noise component (increase the S / N ratio), it is only necessary to increase the degree to which the duty ratio of the output signal changes due to the displacement based on the load to be detected. For this purpose, it is conceivable to increase the inclination angle with respect to the axial direction of the boundary part (step part) between the convex parts 27 and 27 and the concave parts 28 and 28. If this inclination angle is increased, the amount of change in the duty ratio per unit displacement can be increased with respect to the axial displacement of the encoder 12g. However, when the inclination angle is increased, the number of the convex portions 27 and 27 and the concave portions 28 and 28 that can be formed over the entire circumference of the encoder 12g is small (the width of one pitch related to the characteristic change is large). Thus, the number of times (number of pulses) that the output signal of the sensor 13A changes during one rotation of the encoder 12g is reduced. As a result, the load acting between the outer ring 3a and the hub 4b is disadvantageous from the standpoint of obtaining the load in real time, and cannot be used depending on conditions.
In the present reference example , in view of the circumstances as described above, the change in the duty ratio of the output signal of the sensor 13A per unit displacement of the encoder 12g without particularly increasing the inclination angle of the boundary with respect to the axial direction. And the displacement of the encoder 12g, that is, the axial load can be measured with high accuracy.

In the case of this reference example in view of the circumstances as described above, the encoder 12g in which the convex portions 27 and 27 and the concave portions 28 and 28 are alternately arranged on the outer peripheral surface which is a detection surface is rotated. It is externally fitted and fixed to the axially inner end of the hub 4b which is a side race. Further, a sensor 13A supported on a non-rotating portion such as the outer ring 3a or a knuckle constituting the suspension device is disposed above the encoder 12g, and the detection portion of the sensor 13A is disposed at the upper end portion of the outer peripheral surface of the encoder 12g. It is made to oppose to radial direction. Further, among the convex portions 27, 27 and the concave portions 28, 28 formed on the outer peripheral surface of the encoder 12g, the width in the circumferential direction of the concave portions 28, 28 is set to the axial inner end side ( It is wide on the right side in FIG. 25 and narrow on the outer end side (left side in FIG. 25). In the case of the present reference example , with such a configuration, the change in duty ratio of the output signal of the sensor 13A per unit displacement of the encoder 12g can be increased. The load can be measured with high accuracy.

That is, as shown in FIG. 26, there is a predetermined height (wheel radius) between the road surface and the wheel support rolling bearing unit 1a. The axial load generated between the two acts on the wheel bearing rolling bearing unit 1a as a load including a moment load. A relative displacement occurs between the hub 4b and the outer ring 3a due to the load including the moment load. For example, when an axial load is applied from the road surface to the inside of the vehicle body (the right direction in FIG. 25), the entire hub 4b is displaced in the vehicle body inside direction, and at the same time, the hub 4b swings counterclockwise in FIG. Will tend to. As a result, the encoder 12g is displaced in the right direction in FIG. In this way, the axial load is applied between the hub 4b and the outer ring 3a as a load including a moment load, and the hub 4b and the outer ring 3a are relatively displaced. In this case, the direction of the relative displacement between the encoder 12g based on the moment load and the sensor 13A and the direction of the relative displacement between the encoder 12g based on the axial load and the sensor 13A are matched. This is effective in increasing the change in duty ratio of the output signal. This reference example is invented from such a viewpoint.

As is apparent from the description of the sixth example portion of the reference example shown in FIGS. 16 to 18 described above, the duty ratio of the output signal of the sensor 13A changes when the encoder 12g is displaced in the right direction. At the same time, the duty ratio also changes when the encoder 12g is displaced upward. A state in which the duty ratio changes as the encoder 12g is displaced upward will be described with reference to FIG. The vertical axis in FIG. 27 represents the relative displacement between the detection portion of the sensor 13A and the outer peripheral surface (detected surface) of the encoder 12g. However, the same applies to the case where the vertical axis in FIG. In any case, when there is a sag or chamfer at the boundary between the convex portions 27, 27 and the concave portions 28, 28 present on the outer peripheral surface of the encoder 12g, or the detection portion of the sensor 13A. When the diameter (spot diameter) is large, the waveform of the output signal of the sensor 13A is not a perfect rectangular wave but a waveform close to a sine wave.

  If the waveform of the output signal is such a sinusoidal waveform, when the threshold level for identifying the rising and falling edges of the output signal is a constant value, the encoder 12g is displaced toward the sensor 13A. The waveform shown in FIG. 27 is offset overall. That is, as the distance between the detected surface of the encoder 12g and the detection portion of the sensor 13A is shortened, the voltage level of the output signal is increased overall. In this state, as apparent from the intersection of the upper curve and the threshold level in FIG. 27, the proportion of the portion recognized as the convex portions 27, 27 in one cycle of the output signal increases, and the duty ratio is increased. Changes. In other words, the duty ratio of the output signal of the sensor 13A changes without displacement in the axial direction (lateral direction).

  As is clear from the above description, as shown in FIG. 25, when the sensor 13A is disposed above the encoder 12g, the encoder 12g is displaced upward, and the outer peripheral surface of the encoder 12g and the sensor 13A As the distance (gap) from the detection unit decreases, the proportion of the portions recognized as the respective convex portions 27 and 27 in one cycle of the output signal of the sensor 13A increases. Therefore, the displacement of the encoder 12g based on the axial load directed inward in the axial direction (right side in FIG. 25) acting as a load including a moment load is increased in the direction in which the ratio of the convex portions 27 and 27 increases. If 12g is mounted, the direction of relative displacement between the encoder 12g and the sensor 13A based on the moment load is matched with the direction of relative displacement between the encoder 12g and the sensor 13A based on the axial load. The change in the duty ratio of the output signal can be increased. The same applies to the case where an axial load is applied from the road surface to the vehicle body outside direction (left direction in FIG. 25) except that the direction is reversed in the above description.

[ Eleventh Reference Example Related to the Present Invention ]
FIG. 28 shows an eleventh example of reference examples related to the present invention . In the case of this reference example , the sensor 13A is disposed below the encoder 12g, and the detection portion of the sensor 13A is opposed to the lower end portion of the outer peripheral surface of the encoder 12g, which is the detection surface. And the width | variety regarding the circumferential direction of the recessed part 28 and 28 of each convex part 27 and 27 and each recessed part 28 and 28 (refer FIG. 17, 27) formed in the outer peripheral surface of this encoder 12g is made outside an axial direction. It is wide at the end side and narrow at the inner end side as well. That is, in the case of the present reference example, and at the same time turned upside down and the tenth example of the reference example described above the installation position of the sensor 13A, the arrangement of the respective recesses 28, 28, the tenth example of this reference example The inside and outside are reversed.

Also in the case of this reference example , the direction of relative displacement between the encoder 12g and the sensor 13A based on the moment load is matched with the direction of relative displacement between the encoder 12g and the sensor 13A based on the axial load. The change in the duty ratio of the output signal of the sensor 13A can be increased. As in this reference example , when the sensor 13A is installed below the encoder 12g, the lateral displacement caused by the axial load and the lateral displacement caused by the moment load coincide with each other. Is preferable. However, if the sensor 13A is installed below the encoder 12g, the sensor 13A is likely to be damaged by foreign matter such as stones from which the wheels are flipped up. , 12g installation position and installation direction are determined.

[ Twelfth example of a reference example related to the present invention ]
FIG. 29 shows a twelfth example of reference examples related to the present invention . In the case of this reference example , an encoder 12A in which concave portions and convex portions are alternately arranged on the inner side surface in the axial direction that is the detected surface is fixed to the inner end portion in the axial direction of the hub 4b that is the rotating side race. Yes. The detection part of the sensor 13B is made to oppose the axial direction above the to-be-detected surface which exists in the axial direction inner surface of this encoder 12A. Of the unevenness formed on the detection surface of the encoder 12A, the width of the concave portion in the circumferential direction is wide on the radially outer end side and is also narrowed on the inner end side.

  In order to measure the axial load applied from the wheel to the wheel-supporting rolling bearing unit 1a, as shown in FIGS. 25 to 28, the sensor 13A is placed on the detected surface on the circumferential surface of the cylindrical encoder 12g, and the radial direction is set. It is preferable to detect the change in the duty ratio of the output signal of the sensor 13A accompanying the axial load. However, the encoder 12g and the sensor 13A cannot be installed due to restrictions on the installation space, and the sensor 13B may be opposed to the encoder 12A in the axial direction as shown in FIG. As described above, the axial load applied to the wheel support rolling bearing unit 1a from the contact portion between the outer peripheral surface of the wheel and the road surface acts on the wheel support rolling bearing unit 1a as a load including a moment load. Therefore, as described above, the axial load can be obtained even with a structure in which the sensor 13B is opposed to the encoder 12A in the axial direction.

  In this structure, when an axial load is applied to the wheel-supporting rolling bearing unit 1a, for example, from the road surface inward in the axial direction (right side in FIG. 29), the encoder 12A is displaced in the right direction based on the axial load. In addition, the distance (gap) between the detected surface of the encoder 12A and the detection portion of the sensor 13B is reduced. At the same time, the encoder 12A is displaced upward by the moment load. Therefore, the direction (trend) in which the duty ratio of the output signal of the sensor 13B changes due to the upward displacement based on the moment load is the same as the direction in which the duty ratio changes due to the reduction in the distance based on the axial load. If it becomes, the change of the duty ratio as a whole can be enlarged.

As described above, as the distance becomes smaller, the proportion of the portion recognized as a convex portion in one cycle of the output signal increases. Accordingly, if the unevenness formed on the inner surface of the encoder 12A is set so that the ratio of the portion recognized as the convex portion is increased by the upward displacement of the encoder 12A, the axial (including moment load) is set. The change in the duty ratio of the output signal of the sensor 13B accompanying the change in the load can be increased. As in this reference example, the sensor 13B is installed above the encoder 12A, and the width in the circumferential direction of the concave portion of the unevenness formed on the detection surface of the encoder 12A is set to the radially outer end side. If the inner end side is narrow, the direction of relative displacement between the encoder 12A and the sensor 13B based on the moment load and the direction of relative displacement between the encoder 12A and the sensor 13B based on the axial load are set. By matching, the change in the duty ratio of the output signal can be increased.

[ Thirteenth Reference Example Related to the Present Invention ]
FIG. 30 shows a thirteenth example of a reference example related to the present invention . In the case of this reference example , the detection part of the sensor 13B is made to oppose the axial direction in the lower part of the to-be-detected surface which exists in the axial direction inner surface of encoder 12A. Of the unevenness formed on the detection surface of the encoder 12A, the width of the concave portion in the circumferential direction is wide at the radially inner end side and is also narrowed at the outer end side. That is, in the case of the present reference example, and at the same time turned upside down and the twelfth example of the reference example described above the installation position of the sensor 13B, the arrangement of the respective recesses, with respect to the twelfth example and the radial direction of the reference example The inside and outside are reversed.
In the case of this reference example as well, the direction of relative displacement between the encoder 12A and the sensor 13B based on the moment load is matched with the direction of relative displacement between the encoder 12A and the sensor 13B based on the axial load. The change in the duty ratio of the output signal of the sensor 13B can be increased.

[ 14th Reference Example Related to the Present Invention ]
FIG. 31 shows a fourteenth reference example related to the present invention . When the sensor 13d is installed between the rolling elements 5a and 5a arranged in a double row at the axially intermediate portion of the outer ring 3a as in the structure of this reference example , it exists on the detected surface of the encoder 12g. The effect of restricting the direction of the concave and convex portions to be formed is not as remarkable as when the encoder 12g is installed at the inner end portion in the axial direction. However, in order to increase the duty ratio of the output signal of the sensor 13d as much as possible, it is preferable to restrict the direction. The regulation direction in this case is considered as follows.

First, when a sensor is arranged above a cylindrical encoder 12g having an outer peripheral surface as a detection surface and the detection portion of the sensor is opposed to the outer peripheral surface of the encoder 12g in the radial direction, The width in the circumferential direction of the concave portion of the concave portion and the convex portion existing on the outer peripheral surface is set to increase toward the inner side in the axial direction (right side in FIG. 31). Conversely, when the sensor is disposed below the cylindrical encoder 12g and the detection portion of the sensor is opposed to the outer peripheral surface of the encoder 12g in the radial direction, the concave portion present on the outer peripheral surface of the encoder 12g The width in the circumferential direction of the concave portion of the convex portion is made larger toward the outer side in the axial direction (left side in FIG. 31). With this configuration, as in the tenth example of the reference example or the eleventh example of the reference example, the direction of relative displacement between the encoder 12g based on the moment load and the sensor, and those based on the axial load. By changing the direction of relative displacement between the encoder 12g and the sensor, the change in the duty ratio of the output signal of the sensor can be increased.

  If the sensor is installed at the axially outer end of the wheel-supporting rolling bearing unit, the encoder and the sensor based on the moment load have a structure in which the installation position and inclination direction of each part are reversed. The direction of the relative displacement between the encoder and the sensor based on the axial load and the direction of the relative displacement between the encoder and the sensor are made to coincide with each other to increase the change in the duty ratio of the output signal of the sensor. However, since there is almost no possibility of installing it at the axially outer end portion of the wheel bearing rolling bearing unit due to space restrictions, it does not make much sense.

  On the other hand, a sensor is often installed between rolling elements arranged in a double row at the axial intermediate portion of the wheel bearing rolling bearing unit. In such a case, when a load in which an axial load and a moment load are mixed is applied from the wheel to the hub of the wheel bearing rolling bearing unit, the encoder 12g is displaced laterally by the axial load. Further, the hub 4b tends to rotate due to the moment load. Since the center of rotation is between the rolling elements 5a and 5a arranged in a double row, which is the installation position of the encoder 12g, the moment 4 The vertical position of the encoder 12g hardly fluctuates due to the load.

  However, since the encoder 12g is displaced somewhat due to the influence of the vertical load change, even when the encoder 12g is arranged between the rolling elements 5a and 5a arranged in the double row. There is an optimum mounting direction for the encoder 12g. For example, the axial load acts on the inner side of the vehicle body from the road surface is the outer wheel when the car is turning. At this time, the vertical load (radial load) increases due to the centrifugal force. There are many cases. Conversely, for example, the lateral load acting from the road surface toward the vehicle body outer side is the inner wheel when the automobile is turning, and the vertical load is often reduced at this time.

In consideration of such points, in the structure shown in FIG. 31, the detection unit of the sensor 13d installed on the lower side (road surface side) between the rolling elements 5a and 5a arranged in the double row is provided. The lower end of the outer peripheral surface of the encoder 12g is opposed to the encoder 12g. For example, when an axial load is applied from the road surface to the hub 4b in the vehicle body outer direction, the encoder 12g is displaced in the vehicle body outer direction (left direction in FIG. 31) by the axial load. At the same time, the vertical load is reduced, so that the distance (gap) between the detection portion of the sensor 13d and the encoder 12g becomes small. As described above, when this distance is reduced, the proportion of the portion recognized as a convex portion in one cycle of the detection signal of the sensor 13d increases. Therefore, in the case of the present reference example, the width of the concave portion in the circumferential direction becomes larger toward the outer side of the vehicle body so that the rate of recognition as a convex portion increases when the encoder 12g is displaced in the outer direction of the vehicle body. An encoder 12g is arranged.

[ Fifteenth reference example related to the present invention ]
32 to 35 show a fifteenth example of a reference example related to the present invention . In the case of this reference example , as in the fourth example of the reference example shown in FIGS. 11 to 13 described above, an encoder 12k made of a permanent magnet is externally fitted and fixed to the intermediate portion of the hub 4a. On the outer peripheral surface of the encoder 12k, which is the detected surface, there are a portion magnetized in the N pole corresponding to the first detected portion and a portion magnetized in the S pole corresponding to the second detected portion. They are arranged alternately and at equal intervals in the circumferential direction. In particular, in the case of this reference example , the boundary between the part magnetized in the N pole and the part magnetized in the S pole corresponding to the first and second detected parts is defined by the encoder 12k. Inclined by the same angle with respect to the axial direction, and the inclined directions with respect to the axial direction are opposite to each other with the intermediate portion in the axial direction of the encoder 12k as a boundary. Therefore, the portion magnetized in the N pole and the portion magnetized in the S pole have a “<” shape with the axially middle portion protruding (or recessed) most in the circumferential direction.

  On the other hand, a pair of sensors 13i and 13i are installed between the rolling elements 5 and 5 arranged in a double row at the intermediate portion in the axial direction of the outer ring 3, and the detecting portions of both the sensors 13i and 13i are connected to the encoder. The outer peripheral surface of 12k is made to face closely. The positions where the detection parts of these sensors 13i and 13i face the outer peripheral surface of the encoder 12k are the same with respect to the circumferential direction of the encoder 12k. In other words, the detection units of the sensors 13 i and 13 i are arranged on a virtual straight line parallel to the central axis of the outer ring 3. Further, in the state where the axial load is not applied between the outer ring 3 and the hub 4a, the axially intermediate portion between the portion magnetized in the N pole and the portion magnetized in the S pole is the most in the circumferential direction. The installation position of each member 12k, 13i, 13i is regulated so that the protruding part (the part where the inclination direction of the boundary changes) is just at the center position between the detection parts of the sensors 13i, 13i. ing.

In the case of this reference example configured as described above, when an axial load is applied between the outer ring 3 and the hub 4a, the phase in which the output signals of the sensors 13i and 13i change is shifted. That is, in the state where an axial load is not acting between the outer ring 3 and the hub 4a, the detection parts of the sensors 13i and 13i are on the solid lines A and B in FIG. It faces a portion that is shifted in the axial direction by the same amount from the protruding portion. Accordingly, the phases of the output signals of the sensors 13i and 13i coincide as shown in FIG. On the other hand, when a downward axial load is applied to the hub 4a to which the encoder 12k is fixed in FIG. 35A, the detecting portions of the sensors 13i and 13i are shown in FIG. , Opposite to the portions where the deviations in the axial direction from the most protruding portion are different from each other. In this state, the phases of the output signals of the sensors 13i and 13i are shifted as shown in FIG. Furthermore, when an upward axial load acts on the hub 4a to which the encoder 12k is fixed as shown in FIG. 35A, the detecting portions of both the sensors 13i and 13i are connected to the chain-line hub shown in FIG. , C, that is, the deviation in the axial direction from the most protruding portion is opposed to different portions in the opposite direction. In this state, the phases of the output signals of the sensors 13i and 13i are shifted as shown in FIG.

As described above, in the case of this reference example , the phases of the output signals of the sensors 13i and 13i are shifted in the direction corresponding to the direction of the axial load applied between the outer ring 3 and the hub 4a. Further, the degree to which the phases of the output signals of the sensors 13i and 13i are shifted by this axial load increases as the axial load increases. Therefore, in the case of this reference example , based on the presence and absence of a phase shift between the output signals of both the sensors 13i and 13i and the direction and magnitude of the shift, between the outer ring 3 and the hub 4a. The direction and magnitude of the acting axial load can be determined.

[ Sixteenth Reference Example Related to the Present Invention ]
In addition, as in the fifteenth example of the reference example described above, an encoder in which the inclination direction of the boundary between the first detected portion and the second detected portion is changed in the middle and a pair of sensors are combined to form an axial direction. The invention for obtaining the load can be implemented without being limited to the encoder made of the permanent magnet as shown in the figure. That is, one of the first detected part and the second detected part is a through hole, a concave hole, or a convex part, and the other detected part is a through hole or a concave hole adjacent in the circumferential direction. The axial load can also be measured by combining an encoder that is a portion or a recess between the two and an appropriate sensor according to the properties of the encoder. Furthermore, a pair of sensors are arranged to be shifted in the radial direction so as to face one side surface in the axial direction which is a detected surface of the encoder, and the first detected portion and the second detected portion arranged on the detected surface. And the radial load can be measured with a structure in which the inclination direction is changed in the middle of the encoder.

36 to 38 show a sixteenth example of the reference example considered in accordance with the above situation. In the case of this reference example , an encoder 12B made of a magnetic metal plate is fitted and fixed to an intermediate portion of the hub 4a. On the outer peripheral surface of the encoder 12B, which is a detected surface, slit-shaped through holes 33a and 33b corresponding to the first detected portion and column portions 34a and 34b corresponding to the second detected portion are circular. They are arranged alternately and at equal intervals in the circumferential direction. The pitches of the through holes 33a and 33b adjacent to each other in the circumferential direction or the pitches of the column portions 34a and 34b are equal to each other. However, the width of each through hole 33a and 33b in the circumferential direction and the column portions 34a and 34b. The widths in the circumferential direction need not be equal. In particular, in the case of the present reference example, the through holes 33a and 33b corresponding to the first detected portion and the pillar portions 34a and 34b corresponding to the second detected portion are connected to the encoder 12B. Inclination by the same angle with respect to the axial direction is made opposite to each other with respect to the axial direction intermediate portion of the encoder 12B. That is, the encoder 12B of this reference example has through holes 33a, 33a inclined in the same direction in the axial direction on one half of the axial direction, and the predetermined direction in the other half of the axial direction. Through holes 33b and 33b inclined in the opposite direction by the same angle are formed.

  On the other hand, a pair of sensors 13C and 13C are installed between the rolling elements 5 and 5 arranged in a double row in the middle portion in the axial direction of the outer ring 3, and the detectors of both the sensors 13C and 13C are connected to the encoder. The outer peripheral surface of 12B is closely opposed. The positions where the detection parts of both the sensors 13C and 13C face the outer peripheral surface of the encoder 12B are the same with respect to the circumferential direction of the encoder 12B. Further, a rim portion 35 that is located between the through holes 33a and 33b and continues to the entire circumference in a state in which an axial load does not act between the outer ring 3 and the hub 4a is provided between the sensors 13C and 13C. The installation positions of the members 12B, 13C, and 13C are regulated so as to exist at the center position between the detection units.

In the case of the present reference example configured as described above, when an axial load is applied between the outer ring 3 and the hub 4a, the outputs of the sensors 13C and 13C are the same as in the fifteenth example of the reference example described above. The phase at which the signal changes is shifted. That is, in a state where an axial load is not applied between the outer ring 3 and the hub 4a, the detecting portions of the sensors 13C and 13C are on the solid lines A and B in FIG. It faces a portion that is shifted from the portion 35 in the same axial direction. Therefore, the phases of the output signals of the sensors 13C and 13C coincide as shown in FIG. On the other hand, when a downward axial load is applied to the hub 4a to which the encoder 12B is fixed in FIG. 39A, the detecting portions of the sensors 13C and 13C are shown in FIG. The broken lines B and B, that is, the portions that are different from each other in the axial direction from the rim portion 35 face each other. In this state, the phases of the output signals of the sensors 13C and 13C are shifted as shown in FIG. Further, when an upward axial load is applied to the hub 4a to which the encoder 12B is fixed as shown in FIG. 39A, the detecting portions of both the sensors 13C and 13C are connected to the chain line hub of FIG. , C, that is, the axial displacement from the rim 35 opposes different parts in the opposite direction. In this state, the phases of the output signals of the sensors 13C and 13C are shifted as shown in FIG.

As described above, in the case of this reference example as well as the case of the fifteenth example of the reference example, the axial load applied between the outer ring 3 and the hub 4a by the phase of the output signals of both the sensors 13C and 13C. It shifts in the direction according to the direction. Further, the degree to which the phase of the output signals of the sensors 13C and 13C is shifted by this axial load increases as the axial load increases. Therefore, also in the case of this reference example , when there is a phase shift of the output signals of both the sensors 13C and 13C, and there is a shift, it acts between the outer ring 3 and the hub 4a based on the direction and magnitude. The direction and magnitude of the axial load is determined.

In any of the embodiments and reference examples , it is preferable that the area (spot diameter) of the detection portion of the sensor is small. The reason for this is to obtain a pattern change of the characteristic change of the detected surface of the encoder in accordance with the load fluctuation so that the pattern change can be read with high accuracy. The structure of the sensor is not particularly limited, such as a magnetic type or an optical type, but a magnetic type is preferable because it is easy to obtain a sensor having the required accuracy at a low cost. In addition, when using a magnetic sensor, either passive type or active type can be used, but the spot diameter can be reduced and accurate measurement can be performed. Since the measurement can be performed, an active type sensor can be preferably used. Furthermore, if it is an active type sensor, magnetic sensors of various structures can be used including a unipolar type that switches output (ON / OFF) in response to a change in the density of magnetic flux passing through the detection element.

[ Seventeenth Reference Example Related to the Present Invention ]
40 to 41 show a seventeenth example of the reference example considered in accordance with the same situation as the sixteenth example of the reference example described above. In the case of the present reference example , a large number of through holes 33, 33 each having a "<" shape and the same size and shape are arranged at the center in the width direction of the magnetic metal plate encoder 12C. It is formed at equal intervals in the direction. Each of the through holes 33 is formed in a mirror-symmetric shape with the central portion in the width direction of the encoder 12C as a boundary. That is, the encoder 12C of the present reference example has a shape such that the rim portion 35 (see FIGS. 37 to 39) is omitted from the encoder 12B of the sixteenth example of the reference example described above. A portion having the width dimension W _{33 in} which the through holes 33 are formed is defined as an effective range of the encoder 12C.

  The detection portions of the pair of sensors 13D and 13E are placed in close proximity to the detection surface (for example, the outer peripheral surface) of the encoder 12C. These sensors 13D and 13E are each composed of a combination of a magnetic detection element 36 such as a Hall element and a permanent magnet 37. Both the sensors 13D and 13E have a stationary bearing ring (not shown) through a holder (not shown) in a state where the magnetic detection element 36 serving as a detection unit faces the detection surface of the encoder 12C. It is supported and fixed to fixed parts such as. In this state, when the axial load does not act between the stationary-side raceway and the rotation-side raceway, and the positional relationship between the two raceways in the axial direction is in a neutral state, the sensors 13D and 13E As shown in FIG. 41 (A), the detecting section starts from the center position in the width direction of the detected surface of the encoder 12C, that is, from the boundary position where the inclination direction of each of the through holes 33 and 33 changes. Are opposite to each other by the same distances a and b (a = b).

  Note that the distances a and b from the center position in the width direction in the neutral state are larger than the displacement amount c in a state where the stationary side raceway and the rotation side raceway are most displaced in the axial direction (a = b> c). Therefore, as shown in FIG. 41B, even if the stationary side raceway and the rotation side raceway are displaced most in the axial direction, the detection parts of both the sensors 13D and 13E are covered by the encoder 12C. With respect to the width direction of the detection surface, there is no displacement beyond the center position in the width direction (the detection unit straddles the center position in the width direction of the detection surface). For this reason, as long as the stationary side raceway and the rotation side raceway are displaced in the axial direction, the phase difference between the detection signals of the sensors 13D and 13E is determined by the stationary side raceway and the rotation side raceway. Can be increased in proportion to the amount of displacement in the axial direction (the gain when determining the amount of displacement based on the phase difference can be increased).

On the other hand, when the distances a and b from the central position in the width direction are smaller than the displacement c in the most displaced state, as shown in FIG. In a state where the rotation side raceway is most displaced in the axial direction, the detection parts of the sensors 13D and 13E are displaced beyond the center position in the width direction (the detection part straddles the center position in the width direction of the detection surface). ). As a result, the gain for obtaining the displacement amount based on the phase difference becomes small (after the detection unit straddles the center position in the width direction of the detection surface, the gain that has been increased until then starts to decrease). The same phase difference appears for different displacement amounts. As a result, it becomes difficult to accurately determine the amount of displacement based on this phase difference. In contrast, in the case of the present reference example , a = b> c (of course, the same applies to the fifteenth example and the sixteenth example of the reference example described above). It is possible to prevent the gain from decreasing as the value increases and the same phase difference from appearing for different displacement amounts.

  Further, it is preferable to match the positions of the detection portions of the sensors 13D and 13E with respect to the circumferential direction of the encoder 12C as long as there is no problem in the installation space of the sensors 13D and 13E. The reason for this is that by making them coincide, it is easy to properly regulate the phase between the detection portions of the sensors 13D and 13E and the detected surface of the encoder 12C. However, when the installation space is limited, as shown in FIG. 40, both the sensors 13D and 13E can be shifted from each other in the circumferential direction of the encoder 12C. Even in this case, in the neutral state, the phases related to the through holes 33 and 33 of the detection portions of the sensors 13D and 13E are made to coincide with each other. In other words, the shift amount L in the circumferential direction is an integral multiple of the pitch P of these through holes 33 and 33 (L = n · P, where n is a natural number).

Also in the case of this reference example configured as described above, the stationary side race wheel and the rotation side are based on the phase difference between the output signals of the sensors 13D and 13E, as in the sixteenth example of the reference example. A displacement amount in the axial direction with respect to the bearing ring can be obtained, and further, an axial load can be obtained from the displacement amount. That is, in the state where no axial load is acting between these two races, as shown in FIGS. 40 (A) and 41 (A), the detectors of the sensors 13D and 13E are the encoders. 12C exists at the same distance a and b in the width direction from the center position in the width direction of 12C, and there is no phase difference between the output signals of the sensors 13D and 13E. On the other hand, in the state where an axial load is applied between the two race rings, as shown in FIG. 40 (B) and FIG. 41 (B), the detection units of the sensors 13D and 13E The distances a ₁ and b ₁ from the center position in the width direction of the detection surface of the detection surface of the encoder 12C are different (a ₁ ≠ b ₁ ). As a result, a phase difference proportional to the amount of displacement in the axial direction is generated between the output signals of the sensors 13D and 13E. Accordingly, the axial load can be obtained from this phase difference, as in the case of the sixteenth example of the reference example .

[ Eighteenth example of a reference example related to the present invention ]
FIG. 42 shows an eighteenth example of the reference example related to the present invention . This reference example shows the positional relationship between the effective range of the encoder 12g and the detection unit of the sensor 13d in the sixth example of the reference examples shown in FIGS. For such a structure, the effective range W ₁₂ of the sensed surface of the encoder 12g approximately matches the total width of the encoder 12g. And when an axial load does not act between a stationary-side track ring and a rotation-side track ring and the positional relationship regarding the axial direction of these both track rings is in a neutral state, the detection part of the sensor 13d is shown in FIG. As shown in (A) of 42, it faces the center position in the width direction of the detection surface of the encoder 12g. On the other hand, when an axial load acts between the stationary side raceway and the rotation side raceway and the two raceways deviate in the axial direction, the detection unit of the sensor 13d is shown in FIG. As indicated by a chain line in B), it faces a position deviating from the center position in the width direction of the surface to be detected of the encoder 12g. In this case, the detection portion of the sensor 13d is never out of the above scope W _12.

[ Nineteenth Reference Example Related to the Present Invention ]
43 to 44 show a nineteenth example of the reference example related to the present invention . Also in the case of this reference example , for example, load measuring devices are incorporated as shown in FIGS. 1, 7, 11, 14, 16, 19, 22, 25, 26, 28 to 32, 36, which show the above-described reference examples . The rolling bearing unit for this purpose is a wheel bearing rolling bearing unit. The outer ring, which is a stationary side race ring, is supported and fixed to the suspension device in use, and the rotation side race ring is a hub that supports and fixes the wheel and rotates together with the wheel. In particular, in the case of this reference example , the encoder 12D is provided on the outer peripheral edge of the disk rotor 38, which is a member that rotates together with the hub that is the rotating raceway.

  As is well known, the disk rotor 38 is coupled and fixed to the flange 10 provided on the outer peripheral surface of the outer end of the hub 4b as shown in FIG. 26, and rotates together with the hub 4b. Further, since the disk rotor 38 is firmly coupled and fixed to the hub 4b, the disk rotor 38 and the hub 4b are displaced synchronously (integrally). Therefore, if the encoder 12D is provided on the outer peripheral edge of the disk rotor 38 and the detection part of the sensor 13F is opposed to the outer peripheral edge, the axial force applied between the hub 4b and the outer ring 3a (see FIG. 26). The load is required.

  The structure for providing the encoder 12D on the outer peripheral edge of the disk rotor 38 is not particularly limited. In the case of a disk rotor 38 made of a magnetic material such as cast iron, irregularities or holes (concave holes or radial through holes) as shown in FIGS. 43A to 43C are formed directly on the outer peripheral edge. Thus, the magnetic characteristics of the outer peripheral edge of the disk rotor 38 can be changed. In this case, when the disk rotor 38 is of a solid type, irregularities having shapes as shown in FIGS. 43A to 43C are formed on the outer peripheral surface of the disk rotor 38. On the other hand, when the disk 38 is a ventilated type, the disk rotor 38 has a cross-sectional shape as shown in FIGS. 43A to 43C, each of which has a diameter. A through hole penetrating in the direction is formed. On the other hand, when the disk rotor 38 is made of a non-magnetic material such as an aluminum alloy or aluminum composite, the encoder 12D, which is separately formed into an annular shape with a magnetic material, is formed on the outer peripheral edge of the disk rotor 38. Fix externally. Even in this case, when the disk rotor 38 is a solid type, an unevenness is formed on the outer peripheral surface of the encoder 12D, and when it is a ventilated type, a through hole is formed. In the above description, the combination of the encoder 12D and the sensor 13F is a magnetic detection type. In the case of an optical type or the like, even if the disk rotor 38 is made of a non-magnetic material, the irregularities or holes are directly formed on the outer peripheral surface of the disk rotor 38, and this outer peripheral surface is used as a detected surface. Can do.

On the other hand, the sensor 13F is supported on a portion that is not displaced regardless of the load applied to the wheel-supporting rolling bearing unit. As such a part, a knuckle 39 (see FIG. 26) constituting a suspension device and a braking member 40 (see FIG. 44) constituting a disc brake together with the disc rotor 38 can be considered. As the braking member 40, a caliper can be employed when the disc brake is an opposed piston type, and a support can be employed when the disc brake is a floating caliper type. In the case of the illustrated example, the sensor 13 </ b> F is supported on the braking member 40 via a support arm 41. According to the structure of this reference example , the rolling bearing unit with a load measuring device can be realized even when the wheel supporting rolling bearing unit does not have a space for installing the encoder 12D and the sensor 13F. . Contrary to the case shown in the figure, an encoder can be provided on the inner peripheral edge of the annular friction plate for pressing the pad in the disk rotor 38. In this case, the sensor is installed on a stationary member such as an outer ring of a wheel bearing rolling bearing unit.

[ 20th reference example related to the present invention ]
FIG. 45 shows a twentieth example of reference examples related to the present invention . In the case of this reference example , the rolling bearing unit for incorporating the load measuring device is a wheel bearing rolling bearing unit. The outer ring 3a, which is a stationary side race ring, is supported and fixed to the suspension device in use, and the rotation side race ring is a hub 4b that supports and fixes the wheel and rotates together with the wheel. In particular, in the case of the present reference example, the outer peripheral surface of the intermediate portion of the constant velocity joint 42 that is a member that rotates together with the rotation-side raceway and is fixed to the hub 4b is used as the detected surface.

As is well known, the constant velocity joint 42 is for rotating the hub 4b, and rotates together with the hub 4b. Since the constant velocity joint 42 is firmly coupled and fixed to the hub 4b, the constant velocity joint 42 and the hub 4b are displaced synchronously (integrally). Therefore, if the encoder 12E is provided on the outer peripheral surface of the constant velocity joint 42 and the detection portions of the sensors 13G and 13G are opposed to the outer peripheral surface of the encoder 12E, the axial load applied between the hub 4b and the outer ring 3a is increased. Desired. For this reason, in the case of the present reference example , a cylindrical encoder 12E is fitted and fixed to the intermediate portion of the constant velocity joint 42. And the detection part of both said sensors 13G and 13G supported by the knuckle 39 is made to adjoin and oppose the two positions of the outer peripheral surface of the said encoder 12E.
Even in such a structure of this reference example , even in the case where the space for mounting the encoder and sensor cannot be secured in the wheel bearing rolling bearing unit side portion, as in the case of the nineteenth example of the reference example described above, this wheel A structure capable of measuring the load applied to the supporting rolling bearing unit can be realized.
In the case of this reference example , since the temperature rise of the encoder 12E is limited, the encoder 12E is not limited to a magnetic material but can be a permanent magnet (magnetic material). .

DESCRIPTION OF SYMBOLS 1, 1a Rolling bearing unit for wheel support 2 Load measuring device 3, 3a Outer ring 4, 4a, 4b Hub 5, 5a Rolling element 6, 6a Outer ring raceway 7 Mounting portion 8 Hub body 9 Inner ring 10 Flange 11, 11a Inner ring raceway 12, 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h, 12i, 12j, 12k, 12A, 12B, 12C, 12D, 12E Encoder 13, 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h, 13i, 13A, 13B, 13C, 13D, 13E, 13F, 13G Sensor 14, 14a, 14b, 14c Support plate 15, 15a, 15b Encoder body 16 Ring portion 17 Cylindrical portion 18, 18a Cover 19 Bottom plate portion 20, 20a Mounting Hole 21, 21a, 21b Through hole 22, 22a, 22b Between 23 yen Part 24 detected combination part 25 individualized part 26 cylindrical part 27, 27a convex part 28, 28a concave part 29a, 29b parallel part 30a, 30b parallel part 31a, 31b unchanged part 32a, 32b unchanged part 33, 33a, 33b transparent Hole 34a, 34b Column 35 Rim 36 Magnetic sensing element 37 Permanent magnet 38 Disc rotor 39 Knuckle 40 Braking member 41 Support arm 42 Constant velocity joint

Claims (26)

A rolling bearing unit and a load measuring device;
Of these, the rolling bearing unit is present on a stationary bearing ring that does not rotate even in use, a rotating bearing ring that rotates in use, and circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. A plurality of rolling elements provided between the stationary side track and the rotating side track,
The load measuring device is a member that is coupled and fixed to the rotation side raceway or the rotation side raceway and is a member that rotates together with the rotation side raceway or the rotation side raceway. The encoder is supported concentrically with the encoder whose characteristics of the surface to be detected are changed alternately with respect to the circumferential direction, and is supported by a portion that does not rotate with its detecting portion facing this surface to be detected. A sensor that changes the output signal in response to a change in the characteristics of the motor, and a calculator that calculates a load acting between the stationary side raceway and the rotation side raceway based on the output signal of the sensor. And
The pitch or phase at which the characteristics of the detected surface change with respect to the circumferential direction is continuously changing according to the direction of action of the load to be detected,
The arithmetic unit has a function of calculating the load based on a pattern in which an output signal of the sensor changes. A rolling bearing unit with a load measuring device.   The load to be detected is a radial load acting in the radial direction between the stationary side raceway and the rotary side raceway. The detected surface is the axial side surface of the encoder, and the detected surface has different characteristics from each other. The first to-be-detected parts and the second to-be-detected parts are alternately arranged at equal intervals in the circumferential direction, and the width of the first to-be-detected parts is the width of the both to-be-detected parts in the circumferential direction. The rolling bearing unit with a load measuring device according to claim 1, wherein the width is wider toward the outer side in the radial direction, and the width of the second detected portion is wider toward the inner side in the radial direction.   The load to be detected is a radial load acting in the radial direction between the stationary side raceway and the rotary side raceway. The detected surface is the axial side surface of the encoder, and the detected surface has different characteristics from each other. The first detected part and the second detected part having the above are arranged alternately and at equal intervals in the circumferential direction, and the boundary between the first and second detected parts is in the diameter direction of the encoder. The tilt direction with respect to the diametrical direction of the boundary is opposite to the diametrical intermediate part of the encoder, and the diametrical direction is set apart from the diametrical direction of the encoder across the diametrical intermediate part. The rolling bearing unit with a load measuring device according to claim 1, wherein the detection portions of the pair of sensors that are opposed to the detection surface of the encoder.   The encoder is made of a permanent magnet, and one of the first detected part and the second detected part has an N pole, and the other detected part has an S pole. A rolling bearing unit with a load measuring device according to any one of 3 above.   One of the first detected part and the second detected part is a through hole or a concave hole, and the other detected part is between the adjacent through holes or concave holes in the circumferential direction. The rolling bearing unit with a load measuring device according to any one of claims 2 to 3, wherein the rolling bearing unit is a portion that exists.   One of the first detected part and the second detected part is a convex part, and the other detected part is a concave part existing between the convex parts adjacent in the circumferential direction. A rolling bearing unit with a load measuring device according to any one of claims 2 to 3.   The encoder is made of a magnetic material, and the sensor changes the output signal in response to the change in the magnetic characteristics of the detection surface of the encoder. The rolling bearing unit with a load measuring device according to any one of claims 5 to 6, wherein a non-change portion in which a pitch in a rotation direction between the portions does not change in a radial direction exists.   The load to be detected is a radial load acting in the radial direction between the stationary side raceway and the rotary side raceway, and the detected surface is the axial side surface of the encoder. A plurality of combination parts to be detected consisting of a pair of individualized parts having different characteristics from those of the parts are arranged at equal intervals in the circumferential direction, and one pair constituting each of these combination parts for detection 2. The rolling bearing unit with a load measuring device according to claim 1, wherein the intervals between the individualized portions in the circumferential direction continuously change in the same direction with respect to the radial direction in all the combination portions to be detected.   The load to be detected is an axial load acting in the axial direction between the stationary side raceway and the rotary side raceway, and the detected surface is the peripheral surface of the encoder, and the detected surface has different characteristics from each other. The first detected portion and the second detected portion are alternately arranged at equal intervals in the circumferential direction, and the width of the first detected portion is the width of the detected portions in the circumferential direction. The rolling bearing unit with a load measuring device according to claim 1, wherein is wider toward one end in the axial direction, and the width of the second detected portion is wider toward the other end in the axial direction.   The load to be detected is an axial load acting in the axial direction between the stationary side raceway and the rotary side raceway, and the detected surface is the peripheral surface of the encoder, and the detected surface has different characteristics from each other. The first to-be-detected parts and the second to-be-detected parts are alternately arranged at equal intervals in the circumferential direction, and the boundary between these first and second to-be-detected parts is relative to the axial direction of the encoder. In addition to the inclination, the inclination direction of the boundary with respect to the axial direction is opposite to the axial direction intermediate part of the encoder, and the boundary is installed at a position separated in the axial direction of the encoder with the axial intermediate part interposed therebetween. The rolling bearing unit with a load measuring device according to claim 1, wherein a pair of sensors are opposed to a detection surface of the encoder.   The rolling bearing unit with a load measuring device according to any one of claims 9 to 10, wherein the encoder is made of a permanent magnet, the first detected portion is an N pole, and the second detected portion is an S pole.   The first detected part is a through hole or a concave hole, and the second detected part is a portion between the through holes or concave holes adjacent to each other in the circumferential direction. Rolling bearing unit with load measuring device described in 1.   With a load measuring device according to any one of claims 9 to 10, wherein the first detected part is a convex part, and the second detected part is a concave part existing between convex parts adjacent in the circumferential direction. Rolling bearing unit.   The encoder is made of a magnetic material, and the sensor changes the output signal in response to the change in the magnetic characteristics of the detection surface of the encoder. The rolling bearing unit with a load measuring device according to any one of claims 12 to 13, wherein there is a parallel portion in which a pitch in a rotation direction between the portions does not change in an axial direction.   The load to be detected is an axial load acting in the axial direction between the stationary-side raceway and the rotary-side raceway. The detected surface is the peripheral surface of the encoder. A plurality of combination parts for detection composed of a pair of individualized parts having different characteristics from the parts are arranged at equal intervals in the circumferential direction, and each pair constituting the combination parts for detection is arranged. The rolling bearing unit with a load measuring device according to claim 1, wherein the intervals in the circumferential direction between the individualized portions continuously change in the same direction with respect to the axial direction in all of the detected combination portions.   Sensor detection units are made to face each other at three or more positions that differ in the circumferential direction on the detected surface of the encoder, and the computing unit compares the output signals of these sensors so that the stationary-side track ring The rolling bearing unit with a load measuring device according to any one of claims 1 to 15, which has a function of calculating a moment load applied between the rotary bearing ring and the rotating side bearing ring.   The rolling bearing with a load measuring device according to claim 16, wherein the detected surface of the encoder is the peripheral surface of the encoder, and the detecting portions of the sensors are opposed to circumferentially equidistant positions on the peripheral surface of the encoder. unit.   The load measuring device according to claim 16, wherein the detected surface of the encoder is an axial side surface of the encoder, and the detection portions of the sensors are opposed to circumferentially equidistant positions on the axial side surface of the encoder. Rolling bearing unit.   The rolling bearing unit is a wheel bearing rolling bearing unit, and in use, the stationary side bearing ring is supported and fixed to the suspension device, and the rotating side bearing ring supports and fixes the wheel and rotates together with the wheel. A rolling bearing unit with a load measuring device according to any one of 18.   The rolling bearing unit is for rotatably supporting the spindle of the machine tool on the housing, and in use, the outer ring which is a stationary side race ring is fitted and fixed to the housing or a part fixed to the housing. The rolling bearing unit with a load measuring device according to any one of claims 1 to 18, wherein an inner ring which is a rotation side raceway ring is fitted and fixed to the main shaft or a portion rotating with the main shaft.   The rolling bearing unit is a rolling bearing unit for supporting wheels, and in use, the outer ring, which is a stationary side bearing ring, is supported and fixed to the suspension device, and the hub, which is a rotating side bearing ring, supports and fixes the wheel together with this wheel. A double row outer ring raceway that exists on the inner peripheral surface of the outer ring and that is a stationary side raceway and a double row inner ring race that exists on the outer peripheral surface of the hub and that is a rotary side raceway. A plurality of rolling elements are provided for each row between the track and a flange for supporting and fixing the wheel at the axially outer end of the hub. Encoders in which concave and convex portions are alternately arranged are fixed to the inner end of the hub in the axial direction or between the double row inner ring raceways, and the load to be detected is between the outer ring and the hub. Is an axial load acting in the axial direction, The detection portion of the sensor is opposed to the upper portion of the detected surface existing on the outer peripheral surface of the encoder in the radial direction, and the circumferential direction of the concave portion of the unevenness formed on the detected surface of the encoder The rolling bearing unit with a load measuring device according to claim 1, wherein the width is wide on the inner end side in the axial direction and also narrow on the outer end side.   The rolling bearing unit is a rolling bearing unit for supporting wheels, and in use, the outer ring, which is a stationary side bearing ring, is supported and fixed to the suspension device, and the hub, which is a rotating side bearing ring, supports and fixes the wheel together with this wheel. A double row outer ring raceway that exists on the inner peripheral surface of the outer ring and that is a stationary side raceway and a double row inner ring race that exists on the outer peripheral surface of the hub and that is a rotary side raceway. A plurality of rolling elements are provided for each row between the track and a flange for supporting and fixing the wheel at the axially outer end of the hub. Encoders in which concave and convex portions are alternately arranged are fixed to the inner end of the hub in the axial direction or between the double row inner ring raceways, and the load to be detected is between the outer ring and the hub. Is an axial load acting in the axial direction, The detection portion of the sensor is opposed to the lower portion of the detected surface existing on the outer peripheral surface of the encoder in the radial direction, and the circumferential direction of the concave portion of the unevenness formed on the detected surface of the encoder The rolling bearing unit with a load measuring device according to claim 1, wherein the width is wide on the outer end side in the axial direction and also narrow on the inner end side.   The rolling bearing unit is a rolling bearing unit for supporting wheels, and in use, the outer ring, which is a stationary side bearing ring, is supported and fixed to the suspension device, and the hub, which is a rotating side bearing ring, supports and fixes the wheel together with this wheel. A double row outer ring raceway that exists on the inner peripheral surface of the outer ring and that is a stationary side raceway and a double row inner ring race that exists on the outer peripheral surface of the hub and that is a rotary side raceway. A plurality of rolling elements are provided for each row between the track and a flange for supporting and fixing the wheel at the outer axial end of the hub. An axial load, in which the encoder with alternating concave and convex portions on the side is fixed to the inner end of the hub in the axial direction, and the load to be detected acts between the outer ring and the hub in the axial direction. In the axial direction of the encoder The detection part of the sensor is opposed to the upper part of the detected surface existing on the surface in the axial direction, and the width in the circumferential direction of the concave portion of the unevenness formed on the detected surface of the encoder is a diameter. The rolling bearing unit with a load measuring device according to claim 1, which is wide at the outer end side in the direction and narrow at the inner end side.   The rolling bearing unit is a rolling bearing unit for supporting wheels, and in use, the outer ring, which is a stationary side bearing ring, is supported and fixed to the suspension device, and the hub, which is a rotating side bearing ring, supports and fixes the wheel together with this wheel. A double row outer ring raceway that exists on the inner peripheral surface of the outer ring and that is a stationary side raceway and a double row inner ring race that exists on the outer peripheral surface of the hub and that is a rotary side raceway. A plurality of rolling elements are provided for each row between the track and a flange for supporting and fixing the wheel at the outer axial end of the hub. An axial load, in which the encoder with alternating concave and convex portions on the side is fixed to the inner end of the hub in the axial direction, and the load to be detected acts between the outer ring and the hub in the axial direction. In the axial direction of the encoder The detection portion of the sensor is opposed to the lower portion of the detected surface existing on the surface in the axial direction, and the width in the circumferential direction of the concave portion of the unevenness formed on the detected surface of the encoder is a diameter. The rolling bearing unit with a load measuring device according to claim 1, wherein the rolling bearing unit is wide on the inner end side in the direction and narrow on the outer end side.   The rolling bearing unit is a wheel bearing rolling bearing unit, and in use, the stationary side bearing ring is supported and fixed to the suspension device, and the rotating side bearing ring is a hub that supports and fixes the wheel and rotates together with the wheel. 2. The load measurement according to claim 1, wherein the member that rotates together with the rotation-side raceway is a disk rotor constituting a disk brake coupled and fixed to the hub, and the outer peripheral surface of the disk rotor is a detected surface. Rolling bearing unit with device.   The rolling bearing unit is a rolling bearing unit for supporting wheels, and in use, the outer ring, which is a stationary side bearing ring, is supported and fixed to the suspension device, and the hub, which is a rotating side bearing ring, supports and fixes the wheel together with this wheel. The member that rotates and rotates together with the rotation-side raceway is a constant velocity joint that is coupled and fixed to a hub, and a part of an outer peripheral surface of the constant velocity joint is a detected surface. Rolling bearing unit with load measuring device.

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