JP5842536B2 - Rotation support device for wheels - Google Patents

Description

  The present invention relates to a wheel bearing rolling bearing unit for supporting a wheel and a knuckle constituting a part of an independent suspension of an automobile to support the wheel rotatably with respect to the suspension device. The present invention relates to an improvement of a wheel rotation support device.

  In order to support the wheel rotatably with respect to the suspension device, various types of wheel bearing rolling bearing units in which an outer ring and an inner ring are rotatably combined via rolling elements are used. Further, in order to rotatably support the wheel on an independent suspension that is a kind of suspension device, the wheel bearing unit is provided in a support hole (center hole) provided in a knuckle that constitutes a part of the independent suspension. A wheel rotation support device in which a part of an outer ring constituting the inner ring is fitted without rattling and the outer ring and the knuckle are coupled by a plurality of bolts has been widely used. FIG. 7 shows a structure of a wheel rotation support device described in Patent Document 1 as an example of a conventional structure.

The wheel support rolling bearing unit 1 constituting the wheel rotation support device rotatably supports the hub 4 on the inner diameter side of the outer ring 2 via a plurality of balls 5 and 5 that are rolling elements. .
Of these, the outer ring 2 has double-row outer ring raceways 6 and 6 on the inner peripheral surface and a stationary flange 7 on the outer peripheral surface. Such an outer ring 2 does not rotate when the stationary flange 7 is coupled and fixed to the knuckle 8 constituting the suspension device by a plurality of bolts (not shown) during use.
The hub 4 has double-row inner ring raceways 9 and 9 and a rotation side flange 10 on the outer peripheral surface. When used, the hub 4 is fixedly coupled to the rotation side flange 10 and a rotation for braking such as a disk rotor. Rotates with the body.
Such a hub 4 is formed by coupling and fixing a hub body 11 and an inner ring 12. Of these, the hub body 11 is a portion closer to the outer end in the axial direction (outside in the axial direction means the side that is the outer side in the width direction of the vehicle body when assembled to the suspension device, and is the left side of FIGS. The right side of FIGS. 1-7, which is the central side in the width direction of the vehicle, is referred to as “inside” with respect to the axial direction.The same is applied to the outer peripheral surface of the present specification and claims.) Of the double-row inner ring races 9, 9, the inner ring races 9 on the outer side in the axial direction are directly formed on the outer circumferential surface of the axially intermediate portion. In addition, a cylindrical portion 13 called a pilot portion is provided at an outer end portion in the axial direction of the hub main body 11 to externally position the wheel and the brake rotating body.

The inner ring 12 forms an inner ring raceway 9 on the outer peripheral surface on the inner side in the axial direction of the double row inner ring raceways 9, 9. Such an inner ring 12 is fitted by a caulking portion 15 formed at the inner end portion in the axial direction of the hub body 11 in a state where the inner ring 12 is fitted and fixed to a small diameter step portion 14 formed near the inner end portion in the axial direction of the hub body 11. The hub body 11 is fixed and bonded to the hub body 11. A structure in which a nut is screwed to a male thread portion provided at an inner end portion in the axial direction of the hub body 11 in order to couple and fix the inner ring 12 to the hub body 11 is also well known.
Further, a plurality of balls 5 and 5 are held between the outer ring raceways 6 and 6 and the inner ring raceways 9 and 9 by a plurality of retainers 16 and 16 for each row. It is provided in the state.

Further, both axial openings of the rolling element installation space 17 between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 4 in which the balls 5 and 5 are installed are opened by seal rings 18a and 18b. It is blocking.
Further, a cover 19 is fitted on the inner end of the inner ring 12 so as to shield the inner ring 12 and the caulking portion 15 from the external space. The cover 19 includes a bottomed hat (cap) -shaped cover main body 20, a fixing cylindrical portion 21, and an outer diameter side annular portion 22.
Of these, the fixing cylindrical portion 21 is formed in a state of being bent at a right angle from the radial outer end of the cover body 20 to the axially outer side and further folded back 180 degrees.
The outer diameter side annular ring portion 22 extends radially outward from an end portion of the fixing cylindrical portion 21 opposite to the end portion on the side continuous with the cover main body 19. It is formed in the state.
Such a cover 19 is fixed to the inner end portion of the inner ring 12 by fitting the fixing cylindrical portion 21 to the end portion of the inner ring 12 with an interference fit.

  Of the two seal rings 18a, 18b, the seal ring 18b provided on the inner end side in the axial direction is a so-called combination seal ring, and the shaft of the annular portion of the slinger 23 constituting the seal ring 18b. An annular encoder 24 is attached and fixed to the inner side surface in the direction. And the detection part of the sensor 25 which fixed the base end part to the said knuckle 8 is made to oppose the axial direction inner surface of this encoder 24. As shown in FIG.

  Further, a portion of the inner peripheral surface of the center hole 27 of the knuckle 8 that extends from the intermediate portion in the axial direction to the outer end portion in the axial direction is externally fitted to the outer peripheral surface of the outer ring 2 facing this portion. . On the other hand, the portion of the inner peripheral surface of the center hole 27 of the knuckle 8 that is hung from the axially intermediate portion to the axially inner end portion and the outer peripheral edge of the outer diameter side annular ring portion 22 of the cover 19 are close to each other. A labyrinth seal 28 is provided in this portion so as to face each other.

In this way, foreign matter (dust, rainwater, etc.) is prevented from entering the periphery of the seal ring 18b and the sensor installation space 26 in which the sensor 25 is installed, thereby ensuring the durability of the wheel bearing rolling bearing unit. I am trying. However, in the case of this example, the distance in the axial direction between the stationary flange 7 of the outer ring 2 and the outer diameter side circular ring portion 22 of the cover 19 is large. Therefore, in order to constitute the labyrinth seal 28, it is necessary to increase the thickness of the knuckle 8 in the axial direction, which increases the weight of the wheel rotation support device.
Further, when the wheel rotation support device is used, a running state (vehicle speed, turning, road surface state) between the hub 4 and the outer ring 2 (knuckle 8) constituting the wheel rotation support device. The moment load which fluctuates by the change of is added. The hub 4 and the outer ring 2 (the knuckle 8) are imaginary planes including the center of the bearing center (the center position of the outer ring raceways 6 and 6 and the inner ring raceways 9 and 9 in the axial direction) based on the moment load. And the hub 4 and the center axis of the outer ring 2) are swung and displaced in the direction in which the center axes are inclined.
In the case of the above-described conventional structure, a distance in the axial direction between the bearing center and the labyrinth seal 28 is large. For this reason, the fluctuation amount of the gap (gap in the radial direction) of the labyrinth seal 28 based on the swing displacement is large. Accordingly, when the gap in the initial setting state of the labyrinth seal 28 is reduced, the outer peripheral edge of the outer diameter side annular portion 22 of the cover 19 constituting the labyrinth seal 28 and the There is a possibility that the inner peripheral surface of the center hole 27 of the knuckle 8 comes into contact with the inner peripheral surface of the knuckle 8 and the rotation resistance increases or the durability of the cover 19 is lowered due to wear.

JP 2010-230080 A

  In view of the circumstances as described above, the present invention, by devising the structure of the cover of the wheel support rolling bearing unit constituting the wheel rotation support device, and the positional relationship between the cover, the outer ring and the knuckle, The invention has been invented to realize a structure capable of reducing the weight while improving the durability of the wheel bearing rolling bearing unit.

The wheel rotation support device of the present invention includes a knuckle constituting a suspension device and a wheel support rolling bearing unit for rotatably supporting the wheel on the knuckle.
The wheel support rolling bearing unit includes an outer ring equivalent member, an inner ring equivalent member, a plurality of rolling elements, and a cover.
Out of these members, the outer ring equivalent member has a double row outer ring raceway on the inner peripheral surface and a stationary flange for fixing the outer ring to the knuckle on the outer peripheral surface, and does not rotate during use.
The inner ring equivalent member has a double-row inner ring raceway on the outer peripheral surface, and rotates during use.
The rolling elements are provided between the inner ring raceways and the outer ring raceways.
In addition, the cover is supported by the inner ring equivalent member so as to be rotatable together with the inner ring equivalent member, and an axially inner end opening and an outer space of the rolling element installation space in which the rolling elements are installed. It is provided between.

In particular, in the case of the wheel rotation support device of the present invention, the knuckle has a central hole in which the outer peripheral surface of the outer ring equivalent member can be disposed on the inner diameter side of the outer peripheral surface axially inner than the stationary flange. Have
The cover includes an inner diameter side cylindrical portion, an annular portion, and an outer diameter side cylindrical portion.
Among these, the annular portion is provided in a state of extending radially outward from a part of the inner diameter side cylindrical portion.
The outer diameter side cylindrical portion is provided in a state of extending outward in the axial direction from a radially outer end of the annular ring portion.
Further, the inner diameter side cylindrical portion, while supporting fixed to the inner ring member, an outer peripheral surface of the outer ring member and the outer inner periphery of the diameter-side cylindrical portion is closely opposed, and the center of the knuckle The inner peripheral surface of the hole and the opening part of the outer diameter side cylindrical part and the outer ring equivalent member are made to face each other, and a labyrinth seal is provided at these parts that face each other.

Further, when the wheel rotation support device of the present invention as described above is carried out, the ring portion of the cover constituting the wheel support rolling bearing unit is additionally connected to the inner diameter side ring portion. It can be constituted by an outer diameter side circular ring portion provided in a state offset (offset) in the axial direction outside of the inner diameter side circular ring portion, and a continuous stepped portion that makes both the circular ring portions continuous.
In addition, a configuration is adopted in which the axially outer side surface of the outer diameter side circular ring portion and the axially inner end surface of the outer ring equivalent member are closely opposed over the entire circumference, and a labyrinth seal is provided at the closely opposed portion. it can.
Moreover, the structure which inclines the internal peripheral surface of the said continuous level | step-difference part to the direction where an internal diameter becomes large, so that it goes to an axial direction outer side is employable.
Furthermore, the structure which inclines in the direction which an internal diameter becomes large, so that the inner peripheral surface of the outer diameter side cylinder part of the said cover goes to an axial direction outer side is employable.

  In the case of implementing such a wheel rotation support device of the present invention, preferably, as in the invention described in claim 2, at least a part of the outer surface in the axial direction of the circular ring portion and the outer ring equivalent. A labyrinth seal is also provided at a portion facing the inner end surface in the axial direction of the member.

  Further, when the wheel rotation support device of the present invention as described above is implemented, the outer periphery of the outer ring equivalent member constituting the wheel support rolling bearing unit as in the invention described in claim 3 is specifically described. A small-diameter step portion that is recessed radially inward from the outer peripheral surface is formed at the axially inner end portion of the surface. Then, the outer peripheral surface of the small-diameter stepped portion and the inner peripheral surface of the outer-diameter side cylindrical portion of the cover are closely opposed over the entire circumference, and a labyrinth seal is provided at the portion of the small-diameter stepped portion that is closely opposed.

When the wheel rotation support device of the present invention as described above is implemented, the cover is made of a non-magnetic plate, for example, as in the invention described in claim 4 .
The wheel supporting rolling bearing unit is provided with an encoder and a sensor.
Among these encoders, the inner side surface in the axial direction is a detected surface whose magnetic characteristics change alternately in the circumferential direction. Further, the encoder is supported and fixed concentrically with the inner ring equivalent member or the member fixed to the inner ring equivalent member.
Further, the sensor is provided in a state where the detection portion faces the inner side surface in the axial direction of the encoder through the cover.

According to the wheel rotation support device of the present invention configured as described above, it is possible to realize a structure capable of reducing the weight while ensuring the durability of the wheel support rolling bearing unit.
Of these, durability is ensured by providing a labyrinth seal between the rotating cover, the outer ring equivalent member, and the knuckle, so that foreign matter can enter the cover and the rolling element installation space from the external space. This can be achieved by preventing The position of each labyrinth seal in the axial direction is the bearing center (the intersection of the virtual plane including the central position in the axial direction of the outer ring raceway and the inner ring raceway and the central axis of the inner ring equivalent member and the outer ring equivalent member). It is arranged at a position close to For this reason, even when the inner ring equivalent member and the outer ring equivalent member (knuckle) are oscillated and displaced from the road surface during traveling, based on the moment load applied to the wheel rotation support device, the oscillating displacement is based on this oscillating displacement. The amount of variation in the radial gap of each labyrinth seal can be reduced. As a result, the gap between the labyrinth seals in the initial setting state can be reduced to further ensure durability.
The weight can be reduced by reducing the thickness of the knuckle in the axial direction. That is, the axial position of the opening between the outer diameter side cylindrical portion of the cover and the outer ring side equivalent member can be arranged at a position close to the stationary side flange. For this reason, even when the thickness of the knuckle in the axial direction is reduced, a labyrinth seal can be provided in the opening.

Also, the inner peripheral surface of the outer diameter side cylindrical portion constituting the cover and the inner peripheral surface of the continuous stepped portion of the annular ring portion are inclined in a direction in which the inner diameter increases toward the outer side in the axial direction. For this reason, as the foreign matter such as water entering the cover moves radially outward due to the action of centrifugal force, the inner peripheral surface of the outer diameter side cylindrical portion inclined as described above, and It is guided by the inner peripheral surface of the continuous step portion of the circular ring portion and is easily discharged to the external space.

In the case of the invention described in claim 4 , the detection portion of the sensor is opposed to the detection surface of the encoder through the nonmagnetic plate cover. Since this cover rotates together with the member corresponding to the inner ring, foreign matters such as iron pieces, small pieces of ferromagnetic material such as iron powder, and powders are difficult to adhere to the cover. For this reason, the reliability of detection by the sensor can be ensured.

The half part sectional view which shows the structure of the rotation support apparatus for wheels of the 1st example of embodiment of this invention. The A section enlarged view of FIG. The figure similar to FIG. 1 which shows the 2nd example of embodiment of this invention. The B section enlarged view of FIG. The figure similar to FIG. 1 which shows one example of the reference example relevant to this invention . The C section enlarged view of FIG. Sectional drawing which shows the structure of the rotation support apparatus for wheels of a conventional structure.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention . The features of the wheel rotation support device of the present invention including this example are the structure of the cover 29 of the wheel support rolling bearing unit 1a constituting the wheel rotation support device, and the cover 29 and the outer ring 2a. It is in the point which devised the positional relationship with the knuckle 8a. Further, this example shows a case where the present invention is implemented by a wheel bearing rolling bearing unit 1a for driving wheels. Except for the change from the driven wheel to the driving wheel, the configuration and operation of the other parts are basically the same as those of the conventional wheel rotation support device described above. Omitted or simplified, the following description will focus on the features of this example.

The cover 29 of the wheel support rolling bearing unit 1a constituting the wheel rotation support device of this example is formed by bending a metal plate, and includes an inner diameter side cylindrical portion 30, an annular portion 31, and an outer diameter side. It consists of a cylindrical part 32.
Of these, the annular portion 31 includes an inner diameter side annular portion 33, a stepped portion 34, and an outer diameter side annular portion 35.
Among these, the inner diameter side annular ring portion 33 is formed in a state of being bent at a right angle from the axial outer end of the inner diameter side cylindrical portion 30 outward in the radial direction. In other words, the inner diameter side cylindrical portion 30 is provided in a state of being bent at a right angle inward in the axial direction from the radial inner end of the inner diameter side circular ring portion 33.
Further, the stepped portion 34 is formed in a state of being inclined in a direction in which the inner diameter and the outer diameter increase from the radially outer end of the inner diameter side annular ring portion 33 toward the outer side in the axial direction. Note that the stepped portion 34 may have an outer peripheral surface in a cylindrical surface shape that is not inclined, and only the inner peripheral surface may be inclined in the state as described above.
The outer diameter side annular ring portion 35 is formed in a state of being bent radially outward from the axial outer end of the stepped portion 34.

Further, the outer diameter side cylindrical portion 32 is formed in a state where it is bent from the radial outer end of the outer diameter side circular ring portion 35 outward in the axial direction. Further, the inner peripheral surface of the outer diameter side cylindrical portion 32 is a tapered surface that is slightly inclined in the direction in which the inner diameter increases toward the outer side in the axial direction. On the other hand, the outer peripheral surface of the outer diameter side cylindrical portion 32 has a cylindrical surface shape that is not inclined (the outer diameter is constant in the axial direction).
Such a cover 29 is configured such that the inner diameter side cylindrical portion 30 is externally fitted and fixed to an inner ring small diameter portion 36 provided from an axially intermediate portion of the inner ring 12a constituting the hub 4a to an axially inner end portion, The hub 4a can be rotated together.
Also, the labyrinth seal 38 is formed at the portion where the axially outer side surface of the outer diameter side annular portion 35 of the annular portion 31 and the axially inner end surface of the outer ring 2a are opposed to each other. ing. The structure of the labyrinth seal 38 is not limited to the structure of the present example, and the labyrinth seal 38 includes an outer side in the axial direction of the outer-diameter-side circular ring portion 35 and an inner end face in the axial direction of the outer ring 2a. Various structures for enhancing the labyrinth effect, such as a structure in which one or a plurality of grooves are formed over the entire circumference of at least one of the surfaces, can be employed. By adopting a structure in which grooves are formed on the respective surfaces as described above, the sealing performance can be improved.
Also, the inner end side in the axial direction of the pair of seal rings 18a, 18b that closes both ends in the axial direction of the inner diameter side circular ring portion 33 and the rolling element installation space 17 in which the balls 5, 5 are installed. The distance between the axially inner surface of the slinger 23 constituting the seal ring 18b provided on the outer ring 2 is larger than the distance between the axially outer surface of the outer diameter side circular ring portion 35 and the axially inner end surface of the outer ring 2a. A space having a sufficient volume is provided in this portion.

  In addition, the inner peripheral surface of the outer diameter side cylindrical portion 32 and the outer peripheral surface of the outer ring small diameter portion 37 provided at the inner end in the axial direction of the outer ring 2a are made to face each other, and a labyrinth seal is formed on the portion made to face each other. 39 is formed. The structure of the labyrinth seal 39 is not limited to the structure of this example, and at least of the inner peripheral surface of the outer diameter side cylindrical portion 32 and the outer peripheral surface of the outer ring small diameter portion 37 constituting the labyrinth seal 39. Various structures that can enhance the labyrinth effect, such as a structure in which one or a plurality of grooves are formed over the entire circumference of any one of the surfaces, can be employed.

  Further, the portion of the inner peripheral surface of the central hole 27a of the knuckle 8a excluding the portion near the outer end in the axial direction and the outer peripheral surface of the outer diameter side cylindrical portion 32 of the cover 29 are closely opposed to each other, and this proximity facing is performed. The labyrinth seal 41 is formed in the part made to be. In addition, the tip end edge of the outer diameter side cylindrical portion 32 and the stepped surface existing at the innermost end portion of the outer ring small diameter portion 37 are closely opposed to each other, thereby reducing the size of the space 40 of the portion. However, if the axial dimension of the space 40 is increased to some extent and a space 40 having a relatively large volume is provided between the labyrinth seal 39 and the labyrinth seal 41, the labyrinth effect can be further enhanced. . If such a structure is adopted, the hub 4a and the outer ring 2a (the knuckle 8a) are oscillated and displaced based on the moment load applied to the wheel rotation support device from the road surface during traveling, and the space Even when the axial gap of 40 varies, the pumping action due to this variation can be suppressed, and the reduction in the labyrinth effect can be suppressed.

The structure of the labyrinth seal 41 is not limited to the structure of the present embodiment, and the labyrinth seal 41 is composed of an inner peripheral surface of the center hole 27a of the knuckle 8a and an outer peripheral surface of the outer diameter side cylindrical portion 32 constituting the labyrinth seal 41. Various structures for enhancing the labyrinth effect, such as a structure in which one or a plurality of grooves are formed over the entire circumference of at least one of the surfaces, can be employed.
Further, the labyrinth seals 38, 39, 41 as described above are positioned in the axial direction as compared with the labyrinth seal 28 having the conventional structure described above, with the bearing center (the shafts of the outer ring raceways 6, 6 and the inner ring raceways 9, 9 being arranged. It is arranged at a position close to the virtual plane including the center position in the direction and the intersection of the hub 4a and the center axis of the outer ring 2a. In this way, when the labyrinth seals 38, 39, 41 are arranged at positions close to the bearing center in the axial direction, the hub 4a and the outer ring 2a (the knuckle 8a) are based on the moment load as described above. The fluctuation amount of the gap between the labyrinth seals 39 and 41 (the fluctuation amount related to the radial direction) is smaller than the fluctuation amount of the gap of the labyrinth seal 38 (the fluctuation amount related to the axial direction). . Accordingly, the gap between the labyrinth seals 39 and 41 (gap in the radial direction) can be set smaller than the gap between the labyrinth seal 38 (gap in the axial direction) to enhance the labyrinth effect.
The labyrinth seal 41 is not necessarily provided over the entire length of the outer diameter side cylindrical portion 32 in the axial direction. That is, the labyrinth seal 41 may be provided between the inner peripheral surface of the center hole 27a of the knuckle 8a and at least the outer peripheral surface of the outer half portion in the axial direction of the outer diameter side cylindrical portion 32. Thus, if the length of the labyrinth seal 41 in the axial direction is shortened, the thickness of the knuckle 8a in the axial direction can be reduced, so that the weight of the knuckle 8a can be reduced.

  The structure of the knuckle 8a is the same as that of the knuckle 8b of the second example of the embodiment described later. The inner diameter of the center hole 27a is set outside the outer peripheral surface of the outer ring 2a facing the center hole 27a. The outer diameter of the outer diameter side cylindrical portion 32 is larger than the outer diameter of the outer diameter side cylindrical portion 32 so that the fitting state between the knuckle 8a and the outer ring 2a is a large gap fit. It is also possible to adopt a structure that is coupled and fixed only by the above. If such a structure is adopted, the material of the knuckle can be reduced, and the material cost can be reduced and the weight can be reduced.

Further, the length in the axial direction of the outer ring small-diameter portion 37 of the outer ring 2a and the outer-diameter side cylindrical portion 32 of the cover 29 (the position of the tip edge of the outer-diameter side cylindrical portion 32 in the axial direction) is a sealing property. Alternatively, the thickness may be determined appropriately in consideration of the thickness of the knuckle 8b in the axial direction.
Further, as described above, when the fitting state between the knuckle 8a and the outer ring 2a is a large gap fitting, the outer ring small diameter portion 37 may not be formed on the outer ring 2a. In the case of such a structure, the inner diameter of the center hole 27a of the knuckle 8a is made slightly larger than the outer diameter of the outer diameter side cylindrical portion 32 of the cover 29.

According to such a wheel rotation support device of this example, it is possible to reduce the weight while ensuring the durability of the wheel support rolling bearing unit 1a.
Of these, the durability can be ensured by providing the labyrinth seals 38, 39, 41 between the cover 29 and the outer ring 2a and the knuckle 8a. That is, the labyrinth seals 38, 39, 41 can prevent foreign matters from reaching the inside of the cover 29 (around the seal ring 18b) from the external space. As a result, the foreign matter can be prevented from entering the rolling element installation space 17 in which the balls 5 and 5 are arranged, and the durability of the wheel support rolling bearing unit 1a can be ensured. Further, the position of each labyrinth seal 38, 39, 41 in the axial direction is set to the bearing center (the virtual plane including the central position in the axial direction of the outer ring raceway 6, 6 and the inner ring raceway 9, 9), The hub 4a and the outer ring 2a are arranged at positions close to each other). For this reason, even when the hub 4a and the outer ring 2a (the knuckle 8a) are oscillated and displaced from the road surface during traveling based on the moment load applied to the wheel rotation support device, the oscillating displacement is based on the oscillating displacement. The amount of change in the gap between the labyrinth seals 38, 39, 41 can be reduced. As a result, the gap between the labyrinth seals 38, 39, 41 in the initial setting state can be reduced to further ensure durability.

  Further, the weight can be reduced by reducing the thickness of the knuckle 8a in the axial direction. In other words, the tip edge of the outer diameter side cylindrical portion 32 of the cover 29 can be arranged at a position close to the stationary side flange 7a. Therefore, even when the thickness of the knuckle 8a in the axial direction is reduced, the labyrinth seal 41 is provided between the inner peripheral surface of the center hole 27a of the knuckle 8a and the outer peripheral surface of the outer diameter side cylindrical portion 32. I can do things.

  Further, the inner peripheral surface of the outer diameter side cylindrical portion 32 and the inner peripheral surface of the stepped portion 34 of the annular ring portion 31 are inclined in a direction in which the inner diameter becomes larger toward the outer side in the axial direction. For this reason, when foreign matter such as water entering the cover 29 (around the seal ring 18b) moves radially outward by the action of centrifugal force, the inner periphery of the inclined outer diameter side cylindrical portion 32 is inclined. It is guided to the surface and the inner peripheral surface of the stepped portion 34 and is easily discharged to the external space.

[Second Example of Embodiment]
3 to 4 show a second example of the embodiment of the present invention . The cover 29a of the wheel support rolling bearing unit 1b constituting the wheel rotation support device of the present example includes an inner diameter side cylindrical portion 30a, an annular portion 31a, and an outer diameter side cylindrical portion 32a.
Of these, the annular portion 31a includes an inner diameter side annular portion 33a, a stepped portion 34a, and an outer diameter side annular portion 35a.
Particularly in the case of this example, the inner diameter side annular ring portion 33a is provided in a state of being bent at a right angle outwardly in the radial direction from the axial inner end of the inner diameter side cylindrical portion 30a. In other words, the inner diameter side cylindrical portion 30a is provided in a state of being bent outward in the axial direction from the radially inner end of the inner ring portion 33a. That is, in the case of this example, the positional relationship in the axial direction between the inner diameter side circular ring portion 33a and the inner diameter side cylindrical portion 30a is opposite to the first example of the embodiment described above.
In the case of this example, the outer diameter of the outer diameter side cylindrical portion 32a is larger than the outer diameter of the outer peripheral surface of the outer ring 2b (the portion on the inner side in the axial direction from the stationary side flange 7b and excluding the outer ring small diameter portion 37a). . Other basic structures of the cover 29a such as the folding direction are the same as those in the first example of the above-described embodiment.

In such a cover 29a, the inner diameter side cylindrical portion 30a is externally fitted and fixed to the inner ring small diameter portion 36a of the inner ring 12b constituting the hub 4b so as to be rotatable together with the hub 4b.
Further, as in the first example of the above-described embodiment, the axially inner side surface of the outer diameter side circular ring portion 35a and the axially inner end surface of the outer ring 2b are made to face each other, and the parts made to face each other. Is provided with a labyrinth seal 38a.

In the case of this example, the outer ring small-diameter portion 37a provided near the axially inner end portion of the outer ring 2b is formed in a shallower state than the outer ring small-diameter portion 37 of the first example of the above-described embodiment. Yes. In other words, the difference between the outer diameter of the outer peripheral surface of the outer ring 2b (the portion inside the stationary side flange 7b in the axial direction and excluding the outer ring small diameter portion 37a) and the outer diameter of the outer ring small diameter portion 37a is reduced. Yes.
Further, the inner peripheral surface of the outer diameter side cylindrical portion 32a and the outer peripheral surface of the outer ring small diameter portion 37 are made to face each other, and a labyrinth seal 39a is formed at the portion that is made to face each other.

  The inner diameter of the central hole 27b of the knuckle 8b is slightly larger than the outer diameter of the outer diameter side cylindrical portion 32a. The inner peripheral surface of the center hole 27b, the outer peripheral surface of the outer ring 2b, and the outer peripheral surface of the outer diameter side cylindrical portion 32a (the front end edge of the outer diameter side cylindrical portion 32a and the inner end of the outer ring small diameter portion 37a). The labyrinth seal 41a is formed in this portion, in close proximity to each other. In the case of this example, the outer peripheral surface of the outer ring 2b and the inner peripheral surface of the knuckle 8b are connected and fixed only by the stationary flange 7b without being fixedly fitted.

  In such a wheel rotation support device of this example, the inner diameter side cylindrical portion 30a is provided in a state of being bent outward in the axial direction with respect to the circular ring portion 31a constituting the cover 29a. For this reason, the dimension in the axial direction of the inner ring small-diameter portion 36a of the inner ring 12b for externally fitting and fixing the inner diameter side cylindrical portion 30a can be reduced. As a result, the wheel rotation support device can be reduced in size and weight.

  Further, the center hole 27b of the knuckle 8b is enlarged, and the outer ring 2b is coupled and fixed to the knuckle 8b only by the stationary flange 7b. For this reason, the material of the knuckle 8b can be reduced to reduce the material cost and reduce the weight. Other structures, operations and effects are the same as those of the first example of the embodiment described above.

[ One Reference Example Related to the Present Invention ]
5 to 6 show an example of a reference example related to the present invention . The wheel support rolling bearing unit 1c constituting the wheel rotation support device of the present reference example has a rubber on the slinger 23 constituting the seal ring 18b provided on the inner end side in the axial direction of the seal rings 18a and 18b. A ring-shaped encoder 24 is attached and fixed, which is made of a permanent magnet such as a magnet or a plastic magnet. Since the structure of the encoder 24 is the same as that of a conventionally known encoder, detailed description thereof is omitted.

In the case of this reference example , the cover 29b is made of a nonmagnetic plate such as a non-magnetic metal plate such as an aluminum alloy plate or an austenitic stainless steel plate, and has an inner cylindrical portion 30b, an annular portion 31b, It consists of the diameter side cylindrical part 32b.
Of these, the annular portion 31b is provided in a state of being bent at a right angle outwardly in the radial direction from the axially outer end of the inner diameter side cylindrical portion 30b. That is, the annular portion 31b constituting the cover 29b of the present reference example has the step portions 34 and 34a as the annular portions 31 and 31a of the first example and the second example of the embodiment described above. Not.
Further, the outer diameter side cylindrical portion 32b is provided in a state of being bent at a right angle from the radial outer end of the annular ring portion 31b to the outer side in the axial direction.

In such a cover 29b, the inner diameter side cylindrical portion 30b is externally fixed to the inner ring small diameter portion 36 of the inner ring 12a constituting the hub 4a so as to be rotatable together with the hub 4a. Further, a portion closer to the inner end from the radially intermediate portion of the outer circumferential surface of the annular portion 31b and the inner axial surface, which is the detected surface of the encoder 24, are closely opposed (or contacted). .
On the other hand, between the portion near the outer end from the radial intermediate portion of the outer circumferential surface of the circular ring portion 31b and the inner end surface of the outer ring 2a in the axial direction, and the inner periphery of the outer radial side cylindrical portion 32b of the cover 29b Between the surface and the outer peripheral surface of the outer ring small-diameter portion 37 of the outer ring 2a, the inner peripheral surface of the central hole 27a of the knuckle 8a, and the outer peripheral surface of the outer-diameter side cylindrical portion 32b of the cover 29b (this outer diameter side). A labyrinth seal similar to that of the first example of the above-described embodiment is included between the tip edge of the cylindrical portion 32 and a space 40 between the stepped surface existing at the inner end of the outer ring small-diameter portion 37). 38, 39, and 41 are provided. The structure of the knuckle 8a is the same as that of the first example of the embodiment described above.
In the case of this reference example , the detection part of the sensor 42 that supports the base end part of a suspension device is opposed to the detection surface of the encoder 24 via the ring part 31b of the cover 29b. ing.

In such a wheel rotation support device of this reference example , the detection portion of the sensor 42 is opposed to the detection surface of the encoder 24 via the ring portion 31b of the cover 29b. Since the cover 29b rotates together with the hub 4a, foreign matter such as iron pieces, small pieces of ferromagnetic material such as iron powder, and powder are less likely to adhere to the cover 29b. For this reason, the reliability of detection by the sensor 42 can be ensured. Other structures, functions, and effects are the same as those of the first example of the embodiment.

In the first example and the second example of the embodiment described above, the present invention is applied to a wheel bearing rolling bearing unit for driving wheels. However, the present invention is not limited to the conventional structure described above. The present invention can also be applied to a wheel bearing rolling bearing unit for a moving wheel.
Moreover, when implementing this invention, it is not necessary to cover the outer diameter side cylindrical part of a cover with the inner peripheral surface of the center hole of a knuckle. That is, at least the opening of the outer ring and the outer diameter side cylindrical portion of the cover is covered with the inner peripheral surface of the central hole of the knuckle, and a labyrinth seal is provided at this position.

Further, in each example of the embodiment described above and one example of the reference example, the structure in which the outer ring small-diameter portion is provided on the outer peripheral surface of the outer ring near the inner end in the axial direction has been described. It can also be set as the structure which does not provide a part.
In addition, by appropriately changing the length of the outer ring small-diameter portion in the axial direction and the length of the outer-diameter side cylindrical portion in the axial direction, the opening between the outer ring and the outer-diameter side cylindrical portion is formed as described above. It is also possible to set the outer ring closer to the stationary flange than each example of the embodiment and one example of the reference example . In the case of such a structure, the knuckle is reduced in weight and the axial direction of the labyrinth seal provided between the inner peripheral surface of the center hole of the knuckle and the outer ring side cylindrical portion of the outer ring or the cover. The seal length can be improved by increasing the length.

1, 1a, 1b, 1c Wheel bearing rolling bearing unit 2, 2a, 2b Outer ring 4, 4a, 4b Hub 5 Ball 6 Outer ring raceway 7, 7a, 7b Static side flange 8, 8a, 8b Knuckle 9 Inner ring raceway 10 Rotating side Flange 11 Hub body 12, 12a, 12b Inner ring 13 Cylindrical part 14 Small diameter step part 15 Caulking part 16 Cage 17 Roller element installation space 18a, 18b Seal ring 19 Cover 20 Cover body 21 Fixing cylindrical part 22 Outer diameter side annular part 23 Slinger 24 Encoder 25 Sensor 26 Sensor installation space 27, 27a, 27b Center hole 28 Labyrinth seal 29, 29a, 29b Cover 30, 30a, 30b Inner diameter side cylindrical part 31, 31a, 31b Circular ring part 32, 32a, 32b Outer diameter Side cylindrical part 33, 33a Inner diameter side annular part 34, 34a Step part 35, 3 a radially outer circular ring portion 36,36a inner diameter portion 37,37a outer diameter portion 38,38a labyrinth seal 39,39a labyrinth seals 40,40a space 41,41a labyrinth seal 42 sensor

Claims (4)

A knuckle constituting a suspension device, and a wheel bearing rolling bearing unit for rotatably supporting a wheel on the knuckle,
The wheel support rolling bearing unit includes an outer ring equivalent member, an inner ring equivalent member, a plurality of rolling elements, and a cover.
Of these, the outer ring equivalent member has a double row outer ring raceway on the inner peripheral surface, and has a stationary flange for coupling and fixing to the knuckle on the outer peripheral surface, and does not rotate during use.
The inner ring equivalent member has a double-row inner ring raceway on the outer peripheral surface, and rotates during use.
Each of the rolling elements is provided between both the inner ring raceway and the both outer ring raceways,
The cover is supported between the inner ring equivalent member and the inner ring equivalent member so as to be rotatable together with the inner ring equivalent member. Provided in the
In the wheel rotation support device,
The knuckle has a central hole that can be disposed on the inner diameter side of the outer peripheral surface of the outer ring equivalent member, the outer peripheral surface on the axially inner side of the stationary flange,
The cover includes an inner diameter side cylindrical portion, an annular portion, and an outer diameter side cylindrical portion,
Of these, the annular portion is provided so as to extend radially outward from a part of the inner diameter side cylindrical portion, and the inner diameter side annular portion and the inner diameter side annular portion are axially outside. The outer diameter side annular part provided in a biased state and these two annular parts are provided in a continuous state, and the inner peripheral surface is inclined in a direction in which the inner diameter increases as it goes outward in the axial direction. And having a continuous stepped portion,
The outer diameter side cylindrical portion is provided in a state of extending outward in the axial direction from the radial outer end of the annular ring portion , and the inner diameter increases in the direction toward the outer side in the axial direction. Is inclined to
In a state in which the inner diameter side cylindrical portion is supported by and fixed to the inner ring member, and the outer circumferential surface of the inner peripheral surface of the outer diameter side cylindrical portion of the cover and the outer ring member is closely opposed, and the center hole of the knuckle And the outer diameter side cylindrical portion and the opening portion of the outer ring equivalent member are in close proximity to each other, and a labyrinth seal is provided in the proximity facing portion, and the outer diameter side circular ring portion Rotation for a wheel, characterized in that an axially outer surface of the outer ring and an axially inner end surface of the outer ring equivalent member are in close proximity over the entire circumference, and a labyrinth seal is provided in the close-up facing portion. Support device.   At least a part of the outer surface in the axial direction of the annular portion and the inner end surface in the axial direction of the member corresponding to the outer ring are in close proximity to each other, and a labyrinth seal is also provided in the portion in close proximity. Item 2. A rotation support device for a wheel according to item 1.   A small-diameter step portion that is recessed radially inward from the outer peripheral surface is formed at the inner end portion in the axial direction of the outer peripheral surface of the outer ring equivalent member. The outer peripheral surface of the small-diameter step portion and the outer surface of the cover The inner peripheral surface of the diameter side cylindrical portion is closely opposed over the entire circumference, and a labyrinth seal is provided at a portion opposed to the proximity. Rotation support device for wheels. The cover is made of a non-magnetic plate;
The wheel support rolling bearing unit includes an encoder and a sensor,
Of these encoders, the inner surface in the axial direction is a detected surface whose magnetic characteristics change alternately in the circumferential direction, and the inner ring equivalent member or a member fixed to the inner ring equivalent member is concentric with the inner ring equivalent member. Supported and fixed to
The wheel rotation support device according to any one of claims 1 to 3 , wherein the sensor has a detection unit opposed to an inner side surface in the axial direction of the encoder via the cover.

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