JP2007093580A - Rolling bearing unit with displacement measuring device, and the rolling bearing unit with load measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a structure hardly affected by thermal expansion/contraction of a hub 4 or an encoder 12a, accompanying the temperature change in the measurement of moment or axial load. <P>SOLUTION: Through-holes 14a and 14a inclined in one direction are formed in the encoder 12 provided concentrically with the hub 4. Detection parts of a pair of sensors 17c and 17c, supported to an outer ring 3 via a cover 15 are faced with the outer circumferential surface upper end portion and the lower end portion of the encoder 12a. A computing element which has received the detection signals of both the sensors 17c and 17d determines the inclination between the central axis of the outer wheel 3 and the central axis of the hub 4, based on the phase difference between both the detection signals. Furthermore, the computing element finds the moment and the axial load. Since the phase difference will not change due thermal expansion and contraction of each component, above-mentioned problem can be solved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  A rolling bearing unit with a displacement measuring device and a rolling bearing unit with a load measuring device according to the present invention are provided between a stationary side bearing ring and a rotating side bearing ring, which are combined in a relatively rotatable manner via a plurality of rolling elements. The amount of displacement is detected and used to determine the load applied between the stationary side raceway and the rotation side raceway based on this displacement amount or directly. Further, the obtained load is used for ensuring the running stability of a vehicle such as an automobile or for appropriately adjusting the tool feed speed of various machine tools.

  For example, automobile wheels are rotatably supported by a suspension device by a double-row angular type rolling bearing unit. Moreover, in order to ensure the running stability of the automobile, for example, as described in Non-Patent Document 1, an antilock brake system (ABS), a traction control system (TCS), and an electronically controlled stability control A vehicle travel stabilization device such as a system (ESC) is used. In order to control such various vehicle running stabilization devices, signals representing the rotational speed of the wheels, acceleration in each direction applied to the vehicle body, and the like are required. In order to perform higher-level control, it may be preferable to know the magnitude of a load (for example, one or both of a radial load and an axial load) applied to the rolling bearing unit via a wheel.

  In view of such circumstances, 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 this 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 type 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, 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. Furthermore, a method for measuring an axial load applied to a rolling bearing 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 by the 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 method described in Patent Document 3 needs to lower the rigidity of a part of the outer ring equivalent member, which may make it difficult to ensure the durability of the outer ring equivalent member, and obtain sufficient measurement accuracy. Things are considered difficult.

  In view of such circumstances, the present inventors first fixed and supported an encoder on the rotating side bearing ring constituting the double-row angular type rolling bearing unit concentrically with the rotating side bearing ring. An invention for obtaining a relative displacement amount between the rotation side raceway and the stationary side raceway by detecting the displacement of the detection surface was performed (Japanese Patent Application No. 2005-147642). In the case of the structure according to the previous invention, the pitch or phase (characteristic change pattern) at which the characteristic of the detected surface of the encoder changes in the circumferential direction matches the direction of displacement to be detected, and the width direction of the detected surface Is continuously changing. Then, the detection unit of the sensor supported on the stationary part such as the stationary side race ring is brought close to and opposed to the detection surface of the encoder so that the detection signal of the sensor changes according to the relative displacement amount. ing.

FIG. 16 shows an example of such a structure according to the prior invention. The rolling bearing unit with a load measuring device according to the present invention 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-supporting rolling bearing unit 1 includes an outer ring 3, a hub 4, and a plurality of rolling elements 5 and 5. 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 peripheral surface near the inner end. Each of the rolling elements 5 and 5 is provided with a plurality of contact angles in the opposite directions (rear combination type) between the inner ring raceways 11 and 11 and the outer ring raceways 6 and 6, respectively. The hub 4 is rotatably provided, and is supported on the inner diameter side of the outer ring 3 so as to be rotatable concentrically with the outer ring 3.

On the other hand, the load measuring device 2 includes an encoder 12, a sensor unit 13, and a calculator (not shown).
Of these, the encoder 12 is made of a magnetic metal plate such as a mild steel plate, and each of the cylindrical portions provided in the first half is provided with slit-shaped through-holes 14 and 14 in the circumferential direction. Formed at intervals. A pair of sensors 17a and 17b are separated in the axial direction of the encoder 12 (left and right direction in FIG. 16) in a sensor holder 16 supported by a cover 15 fitted and fixed to the inner end of the outer ring 3. keeping. And the detection part of both said sensors 17a and 17b is made to adjoin and oppose the outer peripheral surface of the said encoder 12. FIG. The inclination directions of the through-holes 14 and 14 are opposite to each other between a portion where one sensor 17a faces and a portion where the other sensor 17b faces.

  In the case of an example of the load measuring device of the prior invention configured as described above, when the hub 4 and the outer ring 3 are relatively displaced in the axial direction based on an axial load, the detection signals of the sensors 17a and 17b change. Out of phase. Therefore, based on the magnitude of the deviation, the magnitude of the relative displacement and further the magnitude of the axial load can be obtained. The rotational speed of the hub 4 is obtained based on the detection signal of any one of the sensors 17a (17b).

  The axial load obtained by the rolling bearing unit with a load measuring device according to the above-described prior invention is equivalent to the load generated on the contact surface between the road surface and the wheel (tire). Therefore, if the control for stabilizing the running state of the vehicle is performed based on the obtained load, the feed forward control for preventing the posture of the vehicle from becoming unstable becomes possible. Advanced control to ensure stability is possible.

  In the case of the rolling bearing unit with a load measuring device according to the above-described prior invention, if the magnitude of the axial load acting between the hub 4 and the outer ring 3 is the same, the detection of both the sensors 17a and 17b. It is assumed that the phase difference ratio (phase difference / one cycle) existing between the signals is the same. For example, when the axial load is 0, the detection parts of the sensors 17a and 17b are present at the same position in the opposite direction from the central part of the through holes 14 and 14, and the sensors 17a and 17b. , 17b is assumed to have no phase difference (phase difference ratio = 0).

  On the other hand, if the dimensions of the constituent members of the wheel-supporting rolling bearing unit 1 change as the temperature changes, the above assumption may be lost. For example, the wheel-supporting rolling bearing unit 1 is based on grease agitation resistance or rolling contact between the rolling surfaces of the rolling elements 5 and 5 and the outer ring raceways 6 and 6 and the inner ring raceways 11 and 11. During operation, heat is generated and the temperature rises. The encoder 12 and the cover 15 also rise in temperature as the temperature of each member constituting the wheel support rolling bearing unit 1 rises. The degree of this temperature rise becomes significant in the hub 4 and the encoder 12 that are less likely to be cooled due to being in contact with outside air and less likely to be cooled than in the outer ring 3 and the cover 15.

  As a result, there is a difference between the thermal expansion amount of the outer ring 3 and the cover 15 and the thermal expansion amount of the hub 4 and the encoder 12, and the sensors 17a and 17b supported by the cover 15 and the The encoder 12 is relatively displaced in the axial direction of the encoder 12. When the temperature of each member decreases during cold weather or the like, a relative displacement in the reverse direction may occur. In any case, the relative displacement between the sensors 17a and 17b and the encoder 12 based on such thermal expansion and contraction is independent of the axial load acting between the outer ring 3 and the hub 4. It is an error that occurs. If there is a difference in the coefficient of linear expansion of the material between the constituent members, such an error may become larger. Although the error caused by such a cause is small, it is preferable to eliminate this in order to measure this axial load with high accuracy and to carry out the control for ensuring the running stability of the vehicle.

JP 2001-21577 A Japanese Patent Laid-Open No. 3-209016 Japanese Patent Publication No.62-3365 Motoo Aoyama, “Red Badge Super Illustrated Series / A book that shows the latest mechanics of cars”, p. 138-139, p. 146-149, Sangensha Co., Ltd./Kodansha Co., Ltd., December 20, 2001

  In view of the circumstances as described above, the present invention is to realize a rolling bearing unit with a displacement measuring device and a rolling bearing unit with a load measuring device that are not easily affected by the thermal expansion / contraction of each component constituting a temperature change. Invented.

The rolling bearing unit with a displacement measuring device and the rolling bearing unit with a load measuring device according to the present invention include a rolling bearing unit and a displacement measuring device or a load measuring device.
Of these, the rolling bearing unit is present on the stationary bearing ring that does not rotate even in use, the rotating bearing ring that rotates in use, and the 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 (with a contact angle applied).
In addition, the displacement measuring device or the load measuring device is connected to the rotating side raceway or the rotating side raceway, and the rotation side raceway or the rotation side is partially attached to a member that rotates together with the rotary side raceway. An encoder that is supported concentrically with a member that rotates with the raceway and rotates with the rotation-side raceway, at least a pair of sensors with their respective detectors facing the detection surface of the encoder, and feed from these sensors To obtain the inclination angle between the center axis of the stationary bearing ring and the central axis of the rotating bearing ring or the load acting between the stationary bearing ring and the rotating bearing ring based on the detected signal With a vessel.
The encoder alternately changes the characteristics of the surface to be detected with respect to the circumferential direction, and gradually changes the characteristic change pattern with respect to the width direction of the surface to be detected.
Further, each of the sensors has its detection portion opposed to at least two positions opposite to the diameter direction of the detection surface.
Further, the computing unit may determine the inclination angle between the central axis of the stationary raceway and the central axis of the rotation-side raceway or the stationary side based on the difference in the pattern of detection signals sent from the two sensors. It has a function of obtaining a load acting between the raceway and the rotation side raceway.

  According to the rolling bearing unit with a displacement measuring device and the rolling bearing unit with a load measuring device according to the present invention, the computing unit is configured to detect the central axis of the stationary bearing ring based on the difference in the pattern of detection signals of at least one pair of sensors. An inclination angle with respect to the central axis of the rotation side raceway or a load acting between the stationary side raceway and the rotation side raceway is obtained. Even when the encoder and the sensors are displaced in the axial direction, the difference between the detection signal patterns of the sensors does not change. Therefore, it is possible to realize a structure that is not easily affected by the thermal expansion / contraction of the constituent members accompanying the temperature change.

When the present invention is implemented, for example, as described in claims 2 and 12, the characteristics of the detected surface of the encoder are changed at equal intervals, and the phase of the characteristic change is gradually changed with respect to the width direction of the detected surface. Change. Then, the computing unit is provided with a function of obtaining the tilt angle or the load based on the phase difference between the detection signals sent from the sensors.
Alternatively, as described in claims 3 and 13, the pitch at which the characteristics of the surface to be detected change is gradually changed in the width direction of the surface to be detected. Then, the arithmetic unit is provided with a function of obtaining the tilt angle or the load based on the difference in the duty ratio of the detection signal sent from each sensor.
Regardless of which structure is employed, the computing unit can determine the tilt angle or the load based on the difference (phase difference or duty ratio difference) between detection signal patterns sent from the sensors.

In the case of carrying out the present invention, preferably, as described in claims 4 and 14, first and second characteristic changing portions are provided on the detected surface of the encoder.
Of these, the first characteristic changing portion is provided in one half of the detected surface in the width direction so that the phase of the characteristic change gradually changes at a predetermined angle in a predetermined direction with respect to the width direction of the detected surface.
In addition, the second characteristic changing portion has a characteristic change phase in the other half of the detected surface in the width direction and the same angle as the predetermined angle in a direction opposite to the predetermined direction with respect to the width direction of the detected surface. It is provided in a state that gradually changes.
A total of four sensors are provided, two at each of two positions on the diametrically opposite side of the detected surface.
Then, the detection unit of one of the two sensors provided at both positions is opposed to the first characteristic change unit, and the detection unit of the other sensor is opposed to the second characteristic change unit.
Further, the computing unit is based on the difference between the phase difference between the detection signals of the two sensors arranged at any one position and the phase difference between the detection signals of the two sensors arranged at the other position. Provide the function of obtaining the tilt angle or load.

Alternatively, as described in claims 5 and 15, the pitch at which the characteristics of the surface to be detected change is gradually changed in the width direction of the surface to be detected.
In addition, at the two positions opposite to the diameter direction of the detected surface, a total of four sensors, two each, are shifted in the width direction of the detected surface, and the respective detecting portions are opposed to the detected surface. It is provided in the state where
Further, the arithmetic unit calculates the difference between the duty ratios of the detection signals of the two sensors arranged at any one position and the difference between the duty ratios of the detection signals of the two sensors arranged at the other position. A function for obtaining an inclination angle or a load based on the difference is provided.

  According to the invention described in claims 4, 5, 14, and 15 as described above, even when a load that is not a measurement target (non-target load) is applied in a direction perpendicular to the direction in which each sensor is disposed, It is possible to prevent the measurement value of the target load (target load) from being shifted. For example, when the target load is an axial load applied to the wheel-supporting rolling bearing unit from the contact surface between the wheel and the road surface, the sensors are arranged at two positions above and below the encoder. In this case, when an axial load is applied and the longitudinal load, which is the non-target load, acts in the longitudinal direction, which is the perpendicular direction, the phase difference or the duty ratio difference between the detection signals of the sensors is increased. The load changes separately from the target load. That is, the non-target load becomes crosstalk with respect to the target load measurement, and an error occurs in the measurement value of the target load. On the other hand, according to the invention described in the above-mentioned claims 4, 5, 14, and 15, it is possible to eliminate the influence of the crosstalk and improve the measurement accuracy of the target load.

Moreover, when implementing the invention described in claims 1 to 5 of the present invention, preferably, as described in claim 6, the computing unit includes a central axis of the stationary side raceway and a rotation side raceway. A function for obtaining a moment acting between the stationary side raceway and the rotation side raceway from the inclination angle with the central axis is provided.
In this case, preferably, as described in claim 7, the arithmetic unit is provided with a function for obtaining an axial load acting between the stationary side raceway and the rotation side raceway from the moment.
More preferably, as described in claims 8 and 16, the rolling bearing unit is a wheel bearing rolling bearing unit for supporting a wheel on a suspension device of an automobile, and the stationary-side track ring is used as a suspension device in use. The rotating side race ring is rotated together with the wheel while the wheel is coupled and fixed.
In the case of a wheel-supporting rolling bearing unit, the axial load is applied from the contact portion (grounding surface) between the wheel and the road surface, and therefore does not become a pure axial load but generates a moment. Further, there is a certain relationship between the magnitude of this moment and the magnitude of the axial load input from the ground contact surface, which is determined according to the wheel diameter, the offset amount, and the like. Therefore, if configured as described above, the axial load of the ground contact surface portion can be measured with high accuracy, and the control for ensuring the running stability of the vehicle can be performed at a high level.

Further, when carrying out the invention described in claims 8 and 16 described above, for example, as described in claims 9 and 17, a member that rotates together with the rotating raceway is coupled and fixed to the rotating raceway. The disc rotor constituting the disc brake is an outer peripheral surface of the disc rotor.
Alternatively, as described in claims 10 and 18, the member that rotates together with the rotation-side raceway is a constant-velocity joint that is coupled and fixed to the rotation-side raceway, and a part of the outer peripheral surface of the constant-velocity joint is detected. A surface.
If comprised in this way, the structure which can measure the load added to this wheel support rolling bearing unit is realizable even when the space which mounts an encoder or a sensor cannot be ensured in the wheel bearing rolling bearing unit side part.
In order to obtain the moment or load acting between the rotation side raceway and the stationary side raceway, the inclination between the center axis of the rotation side raceway and the center axis of the stationary side raceway is not necessarily limited. There is no need to find the angle. That is, as described in claim 11, the moment or load applied between the rotating side raceway and the stationary side raceway is calculated on the calculator based on the difference in the pattern of the detection signal sent from each sensor. It is also possible to provide a function for calculating directly (without going through the process of obtaining the tilt angle).

  1 to 5 show a first embodiment of the present invention corresponding to claims 1, 2, 6, 7, 8, 11, 12, and 16. The feature of this embodiment is that the shape of the through holes 14a and 14a formed in the encoder 12a is devised, and a pair of sensors 17c and 17d are provided at two positions opposite to the diametrical direction of the encoder 12a. It is in. Since the structure of the wheel-supporting rolling bearing unit 1 incorporating the displacement measuring device or the load measuring device is the same as that of the prior invention shown in FIG. 16 described above, the overlapping description is omitted or simplified. The description will focus on the features of the embodiment.

  In order to change the characteristics of the outer peripheral surface of the cylindrical portion 18 provided on the front half of the encoder 12a, which is the detection surface of the encoder 12a made of a magnetic metal plate, the cylindrical portion 18 is provided with a slit-shaped transparent portion. The holes 14a and 14a are formed at equal intervals in the circumferential direction. Each of these through-holes 14a and 14a has a linear shape that is inclined with respect to the axial direction of the cylindrical portion 18. A pair of sensors 17c and 17d are supported at two positions on the diametrically opposite side of a part of the inner peripheral surface of the bottomed cylindrical cover 15 fitted and fixed to the inner end of the outer ring 3. Yes. In the case of the present embodiment, since it is intended to obtain the axial load applied in the width direction of the vehicle to the contact portion (grounding surface portion) between the tire 20 constituting the wheel 19 and the road surface 21, one of the sensors 17c. Is fixed to the inner peripheral surface of the upper end portion of the cover 15, and the other sensor 17d is supported and fixed to the inner peripheral surface of the lower end portion of the cover 15. In place of the encoder 12a, a helical gear-shaped object in which concave and convex parts are alternately arranged on the surface to be detected, or a permanent magnet made by alternately arranging S and N poles is used. You can also do it. When a permanent magnet encoder is used, a permanent magnet on the sensor side becomes unnecessary. This point is of course the same in other embodiments.

  In addition, in a state where the central axis of the outer ring 3 and the central axis of the hub 4 (the encoder 12a fitted and fixed to the inner end of the hub 4) coincide with each other, the detecting portions of the sensors 17c and 17d The positions facing the outer peripheral surface are the same positions with respect to the axial direction of the encoder 12a. Therefore, in the neutral state in which the center axis of the outer ring 3 and the center axis of the hub 4 coincide with each other, the phases of the detection signals of the sensors 17c and 17d coincide with each other (no phase difference occurs). In addition, even if the axial dimension of the hub 4 or the encoder 12a changes with the temperature change and the cylindrical portion 18 is translated in the axial direction, the phases of the detection signals of the sensors 17c and 17d are mutually different. There will be no shift (they will remain consistent).

  For example, FIG. 3 shows a case where the phases of the detection signals of the sensors 17c and 17d with respect to the characteristic change of the detection surface of the encoder 12a are opposite to each other (phase difference = 180 degrees). ing. For this purpose, for example, the sensors 17c and 17d are installed in opposite directions, or the directions of the permanent magnets (the directions of the S and N poles) incorporated in the sensors 17c and 17d are reversed. Or electrical processing. Alternatively, at the moment when the detection part of one sensor 17c faces the through hole 14a, the detection part of the other sensor 17d is made to face the portion between the adjacent through holes 14a and 14a. In any case, when no load is applied between the outer ring 3 and the hub 4, as shown in FIG. 3, the detection units of the sensors 17c and 17d are both covered by the encoder 12a. Scan the center of the detection surface. In this state, the detection signals of both the sensors 17c and 17d are in opposite phases, the phase difference is 180 degrees, and the phase difference ratio (phase difference B / 1 period A) is 0.5. In the illustrated example, when the phase difference ratio B / A is 0.5, this indicates that the axial load is zero. When the phase difference ratio B / A is larger than 0.5, the axial load is acting in a predetermined direction. When the phase difference ratio B / A is smaller than 0.5, the axial load is in the predetermined direction. Represents acting in the opposite direction.

  That is, when a moment is applied between the outer ring 3 and the hub 4 and the central axes of the outer ring 3 and the hub 4 are not matched, the phases of the detection signals of the sensors 17c and 17d are shifted from each other (phase difference). Occurs). For example, when a counterclockwise moment as indicated by an arrow in FIG. 1 is applied to the hub 4, the phase of the detection signal of the one sensor 17c is advanced (or delayed) from the neutral state, and the other The phase of the detection signal of the sensor 17d is delayed (or advanced) from the neutral state. As a result, a phase difference is generated between the detection signals of both the sensors 17c and 17d.

  In FIG. 4, an axial load is applied from the left side of FIG. 2, and the encoder 12a is tilted counterclockwise as shown exaggeratedly in the lower left part of FIG. 4 due to the moment based on this axial load. The case where the encoder 12a rotates with the upper part displaced leftward and the lower part moved rightward is shown. In this case, the detectors of both the sensors 17c and 17d are displaced in directions opposite to each other with respect to the width direction of the detection surface of the encoder 12a, so that a phase difference is detected between the detection signals of the sensors 17c and 17d. Will occur. For example, the detection signal of the sensor 17c changes in the direction in which the phase is delayed, and the detection signal of the sensor 17d changes in the direction in which the phase advances. Therefore, the phase difference and the phase difference ratio (B / A) existing between the detection signals of both the sensors 17c and 17d are reduced. Then, the acting direction of the axial load is obtained by the reduction, and the inclination angle of the encoder 12a (inclination angle between the central axes of the outer ring 3 and the hub 4) is obtained by the degree of reduction.

  In addition, according to the structure of the present embodiment, even when the encoder 12a is displaced in the axial direction due to the difference in the amount of thermal expansion described above, the position between the detection signals of both the sensors 17c and 17d is low. There is no phase difference. FIG. 5 shows a state in which the encoder 12a is displaced in the pure axial direction from the state shown in FIG. In the state shown in FIG. 5, the upper and lower parts of the encoder 12a move by the same amount in the same direction depending on the displacement in the axial direction. For this reason, a phase difference does not occur between the detection signals of the sensors 17c and 17d due to the displacement in the axial direction. That is, the phase difference existing between the detection signals of both the sensors 17c and 17d does not change due to the displacement in the axial direction, and the phase difference B of the detection signal shown in FIG. It is the same as the phase difference B in the case shown. This means that the inclination angle of the encoder 12a (the inclination angle between the central axes of the outer ring 3 and the hub 4) is not affected even if axial displacement occurs due to thermal expansion or preload change. Represents what is required.

  Between the phase difference between the detection signals of both the sensors 17c and 17d and the inclination angle between the central axis of the outer ring 3 and the central axis of the hub 4 generated as described above, A predetermined relationship (first relationship) determined by geometrical factors such as the inclination angle θ of the holes 14a, 14a, the pitch P of the rolling elements 5, 5 arranged in a double row, the diameter of the cylindrical portion 18, and the like There is. Therefore, if the equation or map representing the first relationship is stored in a memory in an arithmetic unit (not shown) that processes the detection signals of the sensors 17c and 17d, the phase difference B (phase difference ratio B) is stored. / A) to determine the tilt angle. In addition, there is a certain relationship (second relationship) between the magnitude of the inclination angle and the magnitude of the moment, which is determined by the moment stiffness of the wheel support rolling bearing unit 1. This second relationship is obtained not only by calculation based on the elastic contact theory widely known in the field of rolling bearing units, but also by experiments. Accordingly, if an equation or a map representing the second relationship is stored in the computing unit, the moment can be obtained based on the tilt angle.

  Further, between the magnitude of this moment and the axial load applied in the width direction of the vehicle to the contact portion (grounding surface portion) between the tire 20 and the road surface 21 constituting the wheel 19, the turning radius of the wheel 19, etc. There is a certain relationship (third relationship) that is geometrically determined by. Therefore, if the formula or map representing the third relationship is stored in the memory in the arithmetic unit, the axial load can be obtained based on the moment. The axial load thus determined is equivalent to the load generated on the contact surface between the road surface 21 and the wheel 19 (tire 20). Therefore, if the control for stabilizing the running state of the vehicle is performed based on the obtained axial load, the feed forward control for preventing the posture of the vehicle from becoming unstable becomes possible. Advanced control to ensure running stability is possible. In addition, in the case of the present embodiment, the error based on the temperature change does not enter the value of the obtained axial load. A map representing the relationship between the phase difference between the detection signals of the sensors 17c and 17d and the axial load is created, and the axial load is calculated from the phase difference without obtaining the tilt angle and the moment. You may ask directly.

  6 to 10 show a second embodiment of the present invention corresponding to claims 1, 4, 6, 7, 8, 11, 14, and 16. FIG. Since the structure and the like of the rolling bearing unit portion are the same as the structure according to the above-mentioned prior invention, and further in the case of the above-described first embodiment, the overlapping description is omitted, and the characteristic portions of the present embodiment are hereinafter described. The explanation will be focused on. In the case of the present embodiment, the first and second characteristic changing portions 27 and 28 are provided near the front end of the outer peripheral surface, which is the detected surface of the encoder 12d. Both of these characteristic changing portions 27 and 28 are each provided with a plurality of through holes 14a and 14b each having a slit shape in the circumferential direction, like the cylindrical portion 18 of the encoder 12a incorporated in the first embodiment. They are formed at equal intervals.

  The first characteristic changing unit 27 of the both characteristic changing units 27 and 28 is a half half of the detected surface in the width direction (the right half of FIG. 6, the lower half of the encoder 12d shown in FIGS. 7 to 10). ) In such a state that the phase of the characteristic change gradually changes at a predetermined angle in a predetermined direction with respect to the width direction of the detected surface. On the other hand, the second characteristic changing unit 28 changes the characteristic to the other half of the detected surface in the width direction (the left half of FIG. 6 and the upper half of the encoder 12d shown in FIGS. 7 to 10). Is provided in a state where the phase of the phase gradually changes at the same angle as the predetermined angle in the direction opposite to the predetermined direction with respect to the width direction of the detected surface. For this reason, in the case of the present embodiment, among the through holes 14a and 14b, the through holes 14a and 14a constituting the first characteristic changing portion 27 and the second characteristic changing portion 28 are formed. The through holes 14b and 14b are inclined by the same angle in the opposite direction to the axial direction of the encoder 12d. The through holes 14a and 14a constituting the first characteristic changing portion 27 and the through holes 14b and 14b constituting the second characteristic changing portion 28 are mutually connected as shown in FIGS. It may be formed independently, or may be formed in a continuous state as shown in FIG.

A total of four sensors 17c ₁ , 17c ₂ , 17d ₁ , and 17d ₂ are provided at two positions on the diametrically opposite side of the detected surface. That is, two sensors 17c ₁ and 17c ₂ are arranged above the upper end of the encoder 12d, and the remaining two sensors 17d ₁ and 17d ₂ are arranged below the lower end. Of the two sensors provided at both positions, the detection unit of _one sensor 17c ₁ , 17d ₁ is the first characteristic changing unit 27, and the detection unit of the other sensor 17c ₂ 17d _{2 is} the first sensor. The two characteristic changing portions 28 are opposed to each other. The sensors 17c ₁ , 17c ₂ , 17d ₁ , and 17d _{2 have} no external force applied to them, and the outer ring 3 and the hub 4 are in a neutral state (the central axes coincide with each other and no axial displacement occurs). In the state), it faces the central portion in the width direction of the first characteristic changing unit 27 or the second characteristic changing unit 28.

In the case of the present embodiment in which the sensors 17c ₁ , 17c ₂ , 17d ₁ , 17d ₂ and the encoder 12d are incorporated as described above, the detection signals of these sensors 17c ₁ , 17c ₂ , 17d ₁ , 17d ₂ are obtained. The arithmetic unit to be sent determines the inclination angle of the encoder 12d (inclination angle between the central axis of the outer ring 3 and the central axis of the hub 4) by the following function. That is, the arithmetic unit firstly calculates a ratio (phase difference ratio = phase difference / 1 period) δ _c relating to the phase difference between the detection signals of _two sensors 17c ₁ and 17c ₂ arranged at both upper and lower ends. and obtains a phase difference ratio [delta] _d between the detection signal between the sensor 17d _1, 17d _2. Next, a difference “δ _c −δ _d ” between the phase difference ratios for the _two sensors 17c ₁ and 17c ₂ (17d ₁ and 17d ₂ ) arranged at both positions is obtained. Further, the inclination angle is obtained based on the difference “δ _c −δ _d ” between the phase difference ratios.

According to the structure of the present embodiment as described above, when a load that is not a measurement target (non-target load) is applied in a direction perpendicular to the direction in which the sensors 17c ₁ , 17c ₂ , 17d ₁ , and 17d ₂ are arranged. In addition, it is possible to prevent the measurement value of the load to be measured (target load) from being shifted. In the case of the present embodiment, since the target load is an axial load applied to the wheel-supporting rolling bearing unit from the contact surface between the wheel and the road surface, the sensors 17c ₁ , 17c ₂ , 17d ₁ , and 17d ₂ are connected to the encoder. It is arranged at two positions above and below 12d. In this case, in a state in which the axial load is applied, the front-rear direction load is above the load non-target, to act in the longitudinal direction is the above perpendicular direction, the sensors 17c _1, of 17c _2, 17d _1, 17d ₂ The phase difference ratio of the detection signal changes separately from the target load. That is, the non-target load becomes crosstalk with respect to the target load measurement, and in the structure of the first embodiment, an error occurs in the measurement value of the target load. On the other hand, according to the structure of the present embodiment, the measurement accuracy of the target load can be improved without the influence of the crosstalk.

This point will be described in more detail with reference to FIGS. In the structure of this embodiment, when no external force is applied and the outer ring 3 and the hub 4 are in a neutral state, as shown in FIG. 7, the detection signals of the sensors 17c ₁ and 17c ₂ arranged on the upper side The detection signals of the sensors 17d ₁ and 17d ₂ arranged on the lower side coincide with each other. In the case of the present embodiment, the two sensors 17c ₁ and 17c ₂ arranged at the same position in the circumferential direction, the sensors 17d ₁ and 17d _{2 are} mutually reversed, and the phases of the detection signals are reversed. Therefore, the phase difference between the sensors 17c ₁ and 17c _{2 and} the phase difference between the sensors 17d ₁ and 17d ₂ are 180 degrees and the phase difference ratios δ _c and δ _d (B / A) are respectively 0.5. Further, the difference “δ _d −δ _c ” between the phase difference ratios, which is a parameter for obtaining the inclination angle of the encoder 12d, becomes 0 as shown in the lower end diagram of FIG.

Next, due to the moment based on the axial load applied from the contact surface between the wheel and the road surface, the central axis of the outer ring 3 and the central axis of the hub 4 are inclined, and the encoder 12d swings counterclockwise in FIG. This will be described with reference to FIG. In this case, for example, as shown in the lower left of FIG. 8, the upper part of the encoder 12d is displaced leftward and the lower part is displaced rightward. Of the _two sensors 17d ₁ and 17d ₂ provided on the lower side, the detection signal of _one sensor 17d ₁ is in the direction in which the phase is delayed, and the detection signal of the other sensor 17d ₂ is in the direction in which the phase is advanced. Change. For this reason, the phase difference and the phase difference ratio δ _d between the detection signals of the _two sensors 17d ₁ and 17d ₂ provided on the lower side are increased.

In contrast, the detection signal direction in which the phase advances of one of the sensors 17c ₁ of the two sensors 17c _1, 17c ₂ which is provided on the upper side, the other sensor 17c ₂ in the direction in which the phase is delayed, respectively change To do. For this reason, the phase difference and the phase difference ratio δ _c between the detection signals of the _two sensors 17c ₁ and 17c ₂ provided on the upper side are reduced. As a result, the difference “δ _d −δ _c ” between the phase difference ratios, which is a parameter for obtaining the tilt angle of the encoder 12d, becomes a positive value as shown in the bottom diagram of FIG. . Therefore, based on the difference “δ _d −δ _c ” between the phase difference ratios, the inclination angle of the encoder 12 d, that is, the inclination angle between the central axis of the outer ring 3 and the central axis of the hub 4 can be obtained. . If the relationship between the inclination angle and the moment is obtained in advance, the moment and further the axial load can be obtained from the inclination angle. The axial load may be obtained directly based on the difference “δ _d −δ _c ” between the phase difference ratios as in the case of the first embodiment.

Further, in the case of the embodiment, the encoder 12d are the sensors _{17c 1, 17c 2, 17d 1} , also to 17d ₂ are displaced in the axial direction, the difference "[delta] _d - [delta between the phase difference ratios _c "will not change. FIG. 9 shows a state in which the encoder 12d is displaced in the pure axial direction from the state of FIG. 8 described above. In the state shown in FIG. 9, the upper and lower parts of the encoder 12d are displaced in the same direction as in the state shown in FIG. 8, and the two sensors 17c ₁ and 17c ₂ provided on the upper side are displaced. The phase difference and phase difference ratio δ _c between the detection signals and the phase difference and phase difference ratio δ _d between the detection signals of the _two sensors 17d ₁ and 17d ₂ provided on the lower side change by the same amount in the same direction. To do. As a result, the difference “δ _d −δ _c ” between the phase difference ratios does not change as described above. Therefore, even if an axial displacement occurs due to thermal expansion or a change in preload, the tilt angle can be detected without being affected by the displacement. As in the case of Example 1 described above, the moment and the axial load cannot be obtained when the preload changes.

Further, in the case of the present embodiment, even when the hub 4 is displaced in the front-rear direction with respect to the outer ring 3 due to the force in the front-rear direction, which is a non-target load (the radial displacement in the front-rear direction occurs), It is possible to prevent an error from occurring in the measured value of the tilt angle of the encoder 12d, and thus in the measured value of the axial load, which is the target load, due to the non-target load. This point will be described with reference to FIG. When the encoder 12d is displaced in the front-rear direction by the force in the front-rear direction, the encoder 12d, two sensors 17c ₁ , 17c ₂ provided on the upper side, and two sensors 17d ₁ provided on the lower side, The positional relationship with 17d ₂ shifts (the encoder 12d described in the upper and middle stages of FIG. 10 shifts to the left and right).

However, between the _two sensors 17c ₁ and 17c ₂ provided on the upper side and between the two sensors 17d ₁ and 17d ₂ provided on the lower side, there is a shift with respect to the phase advance / delay of the detection signal. Are in the same direction (in the opposite directions on the upper side and the lower side). For this reason, the phase difference ratio δ _c between the detection signals of the _two sensors 17c ₁ and 17c ₂ provided on the upper side and the position of the detection signals of the _two sensors 17d ₁ and 17d ₂ provided on the lower side. None of the phase difference ratio δ _d changes. Therefore, the difference “δ _d −δ _c ” between the phase difference ratios, which is a parameter for obtaining the tilt angle of the encoder 12d, does not change (same as in FIG. 8). For this reason, even if the encoder 12d is displaced in the front-rear direction due to the force in the front-rear direction applied between the outer ring 3 and the hub 4 based on the driving force or the braking force, the displacement does not affect the inclination angle measurement. This is not crosstalk, and this tilt angle can be obtained with high accuracy.

  FIGS. 11 to 12 show a third embodiment of the present invention corresponding to claims 1, 2, 6, 7, 8, 9, 11, 12, 16, and 17. Also in the case of the present embodiment, for example, as shown in FIGS. 1 and 2 showing the first embodiment, the rolling bearing unit for incorporating the displacement measuring device or the load measuring device is a wheel bearing rolling bearing unit. The outer ring 3 that 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 4 that supports and fixes the wheel 19 and rotates together with the wheel 19. In particular, in the case of the present embodiment, the encoder 12b is provided on the outer peripheral edge of the disk rotor 22, which is a member that rotates together with the rotating raceway.

  As is well known, the disk rotor 22 is coupled and fixed to the flange 10 provided on the outer peripheral surface of the outer end of the hub 4 and rotates together with the hub 4 as shown in FIG. Further, since the disk rotor 22 is firmly coupled and fixed to the hub 4, the disk rotor 22 and the hub 4 are displaced synchronously (integrally). Therefore, if the encoder 12b is provided on the outer peripheral edge of the disk rotor 22 and the detection parts of the sensors 17c and 17d are opposed to the positions opposite to the diameter of the outer peripheral edge, the central axis of the outer ring 3 and the hub Therefore, the axial load applied between the outer ring 3 and the hub 4 is required.

  The structure for providing the encoder 12b on the outer peripheral edge of the disk rotor 22 is not particularly limited. In the case of the disk rotor 22 made of a magnetic material such as cast iron, an unevenness or a hole (a concave hole or a radial through hole) as shown in FIG. The magnetic properties of the outer periphery can be changed. In this case, when the disk rotor 22 is of a solid type, irregularities having a shape as shown in FIG. 11 are formed on the outer peripheral surface of the disk rotor 22. On the other hand, when the disc rotor 22 is a ventilated type, the disc rotor 22 has a cross-sectional shape as shown in FIG. Form. On the other hand, when the disk rotor 22 is made of a nonmagnetic material such as an aluminum alloy or aluminum composite, the encoder 12b, which is separately formed in an annular shape with a magnetic material, is formed on the outer peripheral edge of the disk rotor 22. Fix externally. Even in this case, when the disk rotor 22 is a solid type, an unevenness is formed on the outer peripheral surface of the encoder 12b, and when it is a ventilated type, a through hole is formed. In the above description, the combination of the encoder 12b and the sensors 17c and 17d is a magnetic detection type. In the case of an optical type or the like, even if the disk rotor 22 is made of a non-magnetic material, the irregularities or holes are directly formed on the outer peripheral surface of the disk rotor 22 and this outer peripheral surface is used as a detected surface. Can do.

  On the other hand, both the sensors 17c and 17d are 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 23 (see FIG. 2) constituting a suspension device and a braking member 24 (see FIG. 12) constituting a disc brake together with the disc rotor 22 can be considered. As the braking member 24, a caliper can be used when the disc brake is an opposed piston type, and a support can be used when the disc brake is a floating caliper type. In the illustrated embodiment, the sensors 17c and 17d are supported on the braking member 24 via support arms 25a and 25b, respectively. According to such a structure of the present embodiment, even when the wheel support rolling bearing unit does not have a space for installing the encoder 12b and the sensors 17c and 17d, the rolling bearing with a load measuring device is provided. A unit can be realized.

  FIG. 13 shows a fourth embodiment of the present invention corresponding to claims 1, 2, 6, 7, 8, 10, 11, 12, 16, and 18. Also in the case of the present embodiment, the rolling bearing unit for incorporating the displacement measuring device or the load measuring device is a wheel supporting rolling bearing unit. The outer ring 3a that 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 4a that supports and fixes the wheel and rotates together with the wheel. In the illustrated embodiment, a tapered roller is used as each of the rolling elements 5a and 5a for a rolling bearing unit for supporting a wheel of an automobile that is heavy. In particular, in the case of the present embodiment, the outer peripheral surface of the intermediate portion of the constant velocity joint 26 that is coupled and fixed to the hub 4a, which is a member that rotates together with the rotating side raceway, is used as the detected surface.

As is well known, the constant velocity joint 26 is for rotating the hub 4a, and rotates together with the hub 4a. Since the constant velocity joint 26 is firmly coupled and fixed to the hub 4a, the constant velocity joint 26 and the hub 4a are displaced synchronously (integrally). Therefore, if the encoder 12c is provided on the outer peripheral surface of the constant velocity joint 26, and the detection portions of the sensors 17c and 17d are opposed to the diametrically opposite position of the outer peripheral surface of the encoder 12c, the central axis of the outer ring 3a and the hub The inclination angle with respect to the central axis of 4a, and hence the axial load applied between the outer ring 3a and the hub 4a is obtained. For this reason, in the case of the present embodiment, a cylindrical encoder 12c is externally fixed to the intermediate portion of the constant velocity joint 26. The detection portions of both the sensors 17c and 17d supported by the knuckle 23 are placed close to and opposed to two positions on the outer circumferential surface of the encoder 12c on the diametrically opposite side.
Even with this structure of the present embodiment, even in the case where the space for mounting the encoder 12c and the sensors 17c and 17d cannot be secured in the wheel bearing rolling bearing unit side portion, as in the case of the above-described third embodiment, The structure which can measure the load added to the rolling bearing unit for wheel support is realizable.

  14 to 15 show a fifth embodiment of the present invention corresponding to claims 1, 3, 11 and 13. In the case of the present embodiment, trapezoidal first characteristic portions 29 and second characteristic portions 30 are alternately arranged in the circumferential direction on the outer peripheral surface of the encoder 12e that is the detection surface. Therefore, the pitch at which the characteristic of the outer peripheral surface of the encoder 12e changes gradually changes in the width direction of the outer peripheral surface (the axial direction of the encoder 12e). The detection part of a sensor is made to oppose the upper-end part and lower-end part of the outer peripheral surface of such an encoder 12e, respectively. The duty ratio (high potential duration / one cycle) of the detection signals of both sensors is such that the encoder 12e is not inclined and the detection portions of both sensors are opposed to the center in the width direction of the detection surface. As shown in the upper side of FIG. On the other hand, when the encoder 12e is inclined, as shown in the lower side of FIG. 15, the duty ratio of the detection signal of one sensor is increased, and the duty ratio of the detection signal of the other sensor is decreased. Therefore, the inclination angle of the encoder 12e can be obtained based on the difference in duty ratio between the detection signals of these two sensors. Further, as in the above-described second embodiment, it is possible to eliminate the influence of non-target loads by providing a total of four sensors, two at each part.

  In the first embodiment shown in FIG. 1, the case where the detected surface is the outer peripheral surface of each encoder has been described. On the other hand, the detected surface can be the inner peripheral surface of the encoder. Further, one side surface of the annular encoder in the axial direction can be used as a detection surface, and the detection unit of the pair of sensors can be opposed to the detection surface in the axial direction. Alternatively, the encoder can be provided in the axially intermediate portion of the rotating side raceway, such as a portion between the pair of inner ring raceways 11, 11 on the outer peripheral surface of the hub 4. Furthermore, two sets (four or eight) of sensors can be installed at four positions (two positions at the top and bottom and two positions at the front and rear) at equal intervals in the circumferential direction of the encoder. If comprised in this way, the inclination of the central axes of a stationary-side track ring and a rotation-side track ring is calculated | required not only about an up-down direction (in a vertical surface) but about the front-back direction (in a horizontal surface). The encoder may be a multipolar permanent magnet in which S poles and N poles are alternately arranged on the detection surface.

  Further, as described above, when the present invention is implemented in a rolling bearing unit for supporting a wheel of an automobile, it detects a moment or an axial load and uses it for control, thereby improving the running safety of the automobile. I can plan. Apart from this, even when applied to a rolling bearing unit for general machinery, various practical functions and effects can be obtained. For example, if it is applied to a rolling bearing unit that constitutes the rotation support part of a machine tool, it is possible to perform machining with high accuracy by monitoring the cutting load, and to monitor abnormalities such as excessive input, and the workpiece. It is also possible to prevent damage to machine tools and machines.

Sectional drawing which shows Example 1 of this invention. The schematic sectional drawing of the wheel support part with respect to a suspension apparatus for demonstrating the reason for which an axial load is calculated | required by the structure of Example 1. FIG. The schematic diagram which shows the positional relationship of the detection part of both sensors, and the to-be-detected surface of an encoder in the structure of Example 1, and the state where the axial load is not acting, and the phase of the detection signal of these both sensors. FIG. 4 is a view similar to FIG. 3 showing a state in which an axial load is applied. FIG. 4 is a view similar to FIG. 3 showing a state in which a pure axial displacement is generated at the same time when an axial load is applied. Sectional drawing which shows Example 2 of this invention. The schematic diagram which shows the positional relationship of the detection part of each sensor and the to-be-detected surface of an encoder, and the phase of the detection signal of both these sensors in the structure of Example 2 in the state where the axial load is not acting. FIG. 8 is a view similar to FIG. 7 showing a state in which an axial load is applied. FIG. 8 is a view similar to FIG. 7 showing a state in which pure axial displacement is generated at the same time when an axial load is applied. Similarly, the same figure as FIG. 7 which shows the state which the radial load of the front-back direction acted simultaneously with the axial load acting. FIG. 9 is a schematic side view showing a shape of a detection surface provided on an outer peripheral edge portion of a disk rotor, showing Embodiment 3 of the present invention. The front view and side view which show an example of the attachment state of a sensor. Sectional drawing which shows Example 4 of this invention. FIG. 10 is a schematic diagram illustrating another example of the characteristic change pattern of the detection target surface of the encoder as the fifth embodiment of the present invention. The diagram which shows the detection signal of the sensor which changes corresponding to the pattern of the to-be-detected surface shown in FIG. Sectional drawing of an example of the rolling bearing unit with a load measuring device which concerns on a prior invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rolling bearing unit for wheel support 2 Load measuring device 3, 3a Outer ring 4, 4a Hub 5, 5a Rolling body 6 Outer ring raceway 7 Mounting part 8 Hub body 9 Inner ring 10 Flange 11 Inner ring raceway 12, 12a, 12b, 12c, 12d, 12e encoder 13 sensor unit 14, 14a, 14b through holes 15 cover 16 sensor holder 17a, 17b, 17c, 17d, 17c 1, 17c 2, 17d 1, 17d 2 sensor 18 cylindrical portion 19 a wheel 20 tire 21 road 22 disc rotor 23 knuckle 24 braking member 25a, 25b support arm 26 constant velocity joint 27 first characteristic change part 28 second characteristic change part 29 first characteristic part 30 second characteristic part

Claims (18)

A rolling bearing unit and a displacement 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 displacement 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. And an encoder that rotates concentrically with the rotation-side raceway, at least one pair of sensors with their respective detectors facing the detection surface of the encoder, and detection signals sent from these sensors. An arithmetic unit for obtaining an inclination angle between the central axis of the stationary bearing ring and the central axis of the rotating bearing ring;
The encoder alternately changes the characteristics of the detected surface with respect to the circumferential direction, and gradually changes the characteristic change pattern with respect to the width direction of the detected surface.
Each of the above-mentioned sensors has the respective detection parts opposed to at least two positions opposite to the diameter direction of the detection surface,
The arithmetic unit has a function of obtaining an inclination angle between the center axis of the stationary side raceway and the center axis of the rotation side raceway based on the difference in the pattern of detection signals sent from the sensors. Rolling bearing unit.   The characteristics of the detected surface change at equal intervals, the phase of the characteristic change gradually changes in the width direction of the detected surface, and the computing unit is based on the phase difference of the detection signals sent from each sensor. The rolling bearing unit with a displacement measuring device according to claim 1, wherein an inclination angle is obtained.   The pitch at which the characteristics of the surface to be detected change gradually in the width direction of the surface to be detected, and the computing unit obtains an inclination angle based on a difference in duty ratio of detection signals sent from each sensor. Rolling bearing unit with displacement measuring device described in 1.   A first characteristic changing portion in which the phase of the characteristic change gradually changes at a predetermined angle in a predetermined direction with respect to the width direction of the detected surface is provided on one half of the width direction of the detected surface. Each of which is provided with a second characteristic change section in which the phase of the characteristic change gradually changes at the same angle as the predetermined angle in a direction opposite to the predetermined direction with respect to the width direction of the detected surface. A total of four sensors are provided at two positions opposite to each other in the diametrical direction of the surface, and the detection part of one of the two sensors provided at both positions is used as the first characteristic. The detecting unit of the other sensor is opposed to the second characteristic changing unit to the changing unit, and the computing unit includes a phase difference between detection signals of two sensors arranged at any one position, and The difference between the phase difference between the detection signals of the two sensors placed at the other position Zui by obtaining the inclination angle, the displacement measuring rolling bearing unit according to claim 1.   The pitch at which the characteristics of the surface to be detected changes gradually in the width direction of the surface to be detected, and a total of 4 sensors, 2 each, are placed at 2 positions opposite to the diameter direction of the surface to be detected. The detector is shifted in the width direction of the detection surface, and each detection unit is provided in a state of facing the detection surface, and the computing unit is a duty of detection signals of two sensors arranged at one of the positions. The rolling bearing unit with a displacement measuring device according to claim 1, wherein an inclination angle is obtained based on a difference between a ratio and a difference between duty ratios of detection signals of two sensors arranged at the other position.   The computing unit has a function of obtaining a moment acting between the stationary side bearing ring and the rotating side bearing ring from an inclination angle between the central axis of the stationary side bearing ring and the central axis of the rotating side bearing ring. A rolling bearing unit with a displacement measuring device according to any one of 1 to 5.   The arithmetic unit has a function of obtaining an axial load acting between the stationary side raceway and the rotation side raceway from a moment acting between the stationary side raceway and the rotation side raceway. Rolling bearing unit with displacement measuring device described.   The rolling bearing unit is a wheel bearing rolling bearing unit for supporting the wheel on the automobile suspension system. The stationary side bearing ring is coupled and fixed to the suspension system in use, and the rotating side bearing ring is coupled and fixed to the wheel. The rolling bearing unit with a displacement measuring device according to claim 7, wherein the rolling bearing unit rotates with the wheel in a state.   The displacement according to claim 8, wherein the member that rotates together with the rotation-side raceway is a disc rotor constituting a disc brake coupled and fixed to the rotation-side raceway, and the outer peripheral surface of the disc rotor is a detected surface. Rolling bearing unit with measuring device.   The displacement measurement according to claim 8, wherein the member that rotates together with the rotation-side raceway is a constant velocity joint that is coupled and fixed to the rotation-side raceway, and a partial outer peripheral surface of the constant-velocity joint is a detected surface. Rolling bearing unit with device. 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. And an encoder that rotates concentrically with the rotation-side raceway, at least one pair of sensors with their respective detectors facing the detection surface of the encoder, and detection signals sent from these sensors. An arithmetic unit for obtaining a load acting between the stationary side raceway and the rotation side raceway,
The encoder alternately changes the characteristics of the detected surface with respect to the circumferential direction, and gradually changes the characteristic change pattern with respect to the width direction of the detected surface.
Each of the above-mentioned sensors has the respective detection parts opposed to at least two positions opposite to the diameter direction of the detection surface,
The arithmetic unit has a function of obtaining a load applied between the stationary side race ring and the rotation side race ring based on a difference in pattern of detection signals sent from the sensors. .   The characteristics of the detected surface change at equal intervals, the phase of the characteristic change gradually changes in the width direction of the detected surface, and the computing unit is based on the phase difference of the detection signals sent from each sensor. The rolling bearing unit with a load measuring device according to claim 11, wherein the load is obtained.   The pitch at which the characteristics of the surface to be detected change gradually in the width direction of the surface to be detected, and the computing unit obtains a load based on a difference in duty ratio of detection signals sent from each sensor. Rolling bearing unit with load measuring device described.   A first characteristic changing portion in which the phase of the characteristic change gradually changes at a predetermined angle in a predetermined direction with respect to the width direction of the detected surface is provided on one half of the width direction of the detected surface. Each of which is provided with a second characteristic change section in which the phase of the characteristic change gradually changes at the same angle as the predetermined angle in a direction opposite to the predetermined direction with respect to the width direction of the detected surface. A total of four sensors are provided at two positions opposite to each other in the diametrical direction of the surface, and the detection part of one of the two sensors provided at both positions is used as the first characteristic. The detecting unit of the other sensor is opposed to the second characteristic changing unit to the changing unit, and the computing unit includes a phase difference between detection signals of two sensors arranged at any one position, and The difference between the phase difference between the detection signals of the two sensors placed at the other position Request load Zui, load measuring rolling bearing unit according to claim 11.   The pitch at which the characteristics of the surface to be detected changes gradually in the width direction of the surface to be detected, and a total of 4 sensors, 2 each, are placed at 2 positions opposite to the diameter direction of the surface to be detected. The detector is shifted in the width direction of the detection surface, and each detection unit is provided in a state of facing the detection surface, and the computing unit is a duty of detection signals of two sensors arranged at one of the positions. The rolling bearing unit with a load measuring device according to claim 11, wherein a load is obtained based on a difference between a ratio difference and a difference between duty ratios of detection signals of two sensors arranged at the other position.   The rolling bearing unit is a wheel bearing rolling bearing unit for supporting the wheel on the automobile suspension system. The stationary side bearing ring is coupled and fixed to the suspension system in use, and the rotating side bearing ring is coupled and fixed to the wheel. The rolling bearing unit with a load measuring device according to any one of claims 11 to 15, which rotates together with the wheel in a state.   The load according to claim 16, wherein the member that rotates together with the rotation-side raceway is a disc rotor constituting a disc brake coupled and fixed to the rotation-side raceway, and the outer peripheral surface of the disc rotor is a detected surface. Rolling bearing unit with measuring device.   The load measurement according to claim 16, wherein the member that rotates together with the rotation-side raceway is a constant velocity joint that is coupled and fixed to the rotation-side raceway, and a part of the outer peripheral surface of the constant velocity joint is a detected surface. Rolling bearing unit with device.

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