JP6809191B2 - Rolling bearing unit - Google Patents

Description

The present invention relates to, for example, an improvement in a rolling bearing unit used to rotatably support an automobile wheel with respect to a suspension device.

For example, as shown in FIG. 6, the wheels of an automobile are rotatably supported by a rolling bearing unit 1 for supporting the wheels with respect to the suspension device. The rolling bearing unit 1 rotatably supports a hub 3 on the inner diameter side of the outer ring 2 via a plurality of rolling elements 4 and 4. The outer ring 2 has a stationary side flange 5 on the outer peripheral surface for supporting the suspension device, and has double-row outer ring tracks 6a and 6b on the inner peripheral surface. The hub 3 is configured by connecting the hub main body 7 and the inner ring 8 with a nut 9, and has a double-row inner ring track 10a and 10b on the outer peripheral surface. A plurality of rolling elements 4 and 4 are rotatably provided between the inner ring tracks 10a and 10b and the outer ring tracks 6a and 6b while being held by the cages 11 and 11, respectively. There is.

On the outer peripheral surface of the hub body 7, a portion of the outer ring 2 that protrudes outward in the axial direction from the opening at the outer end in the axial direction is provided with a rotation-side flange 12 that protrudes outward in the radial direction. Wheels constituting the wheels are attached to the rotating side flange 12 by using a plurality of studs 13.
In the present specification and claims, the inside in the axial direction means the side that is the center side in the width direction of the vehicle when assembled to the vehicle, and the outside is the side that is the outside in the width direction of the vehicle. Say.

A sealing device 14 is mounted between the outer end of the outer ring 2 in the axial direction and the outer peripheral surface of the intermediate portion in the axial direction of the hub 3. As a result, the axial outer end opening of the internal space 15 existing between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3 is closed. On the other hand, a bottomed cylindrical cover 16 is attached to the axial inner end of the outer ring 2 to close the axial inner end opening of the outer ring 2.

The sealing device 14 that closes the axial outer end opening of the internal space 15 prevents foreign matter guided inward in the radial direction along the axial inner side surface of the rotating side flange 12 from entering the internal space 15. If necessary, excellent sealing performance is required. In view of such circumstances, various structures have been conventionally considered as a sealing device for sealing the axial outer end opening of the internal space. FIG. 7 shows the sealing device 14 described in Patent Document 1.

The sealing device 14 includes a sliding contact ring 17 and a sealing ring 18.
Of these, the sliding contact ring 17 is made of a metal plate and has an annular shape as a whole, and is externally fitted and fixed to a portion of the outer peripheral surface of the hub body 7 adjacent to the inside of the rotating flange 12 in the axial direction. ing. The seal ring 18 includes a core metal 19 that is externally fitted and fixed to the axially outer end portion of the outer ring 2, and an elastic material and an annular seal material 20 that is reinforced by the core metal 19. The seal material 20 is provided with three seal lips 21a to 21c, each of which has its tip edge slidably contacted with the surface of the sliding contact ring 17 over the entire circumference.

The sealing device 14 having the above-described configuration and having a conventional structure employs not the surface of the hub 3 but the surface of the sliding contact ring 17 made of a metal plate as the mating surface for sliding the tip edges of the seal lips 21a to 21c. doing. For this reason, it is possible to prevent problems such as seal squeal and sticking of the seal lip, such as when the tip edge of the seal lip is slidably contacted with the surface of the hub where grinding lines are likely to occur due to the grinding process.

However, in the case of the conventional structure, the axial inner surface of the rotating side flange 12 and the axial outer surface of the sliding contact ring 17 are in direct contact with each other, and the contact portion is not covered with a seal member or the like. For this reason, foreign matter such as muddy water may enter the contact portion between the axial inner surface of the rotating side flange 12 and the axial outer surface of the sliding contact ring 17, causing rust. Further, since a moment (swivel moment) force is applied to the rotating side flange 12 that rotates together with the wheels based on the road surface reaction force, the flange 12 is externally fitted and fixed to the axial inner surface of the rotating side flange 12 and the outer peripheral surface of the hub body 7. There is a possibility that the outer surface of the sliding contact ring 17 in the axial direction is displaced relative to each other and rubs against each other. Therefore, there is a possibility that fretting wear may occur on the axial inner surface of the rotating side flange 12 and the axial outer surface of the sliding contact ring 17. Further, such fretting wear progresses even faster when rust is generated on the axial inner surface of the rotating side flange 12 or the axial outer surface of the sliding contact ring 17.

In view of the above circumstances, for example, in Patent Documents 2 and 3, a sealing seal is attached and fixed to the radial outer end of the axial outer surface of the sliding contact ring, and this sealing seal is attached and fixed in the axial direction of the rotating side flange. A structure is described in which the axial outer surface of the sliding contact ring and the axial inner surface of the rotating flange are separated from each other or the number of contact portions is reduced by abutting the inner side surface. In the case of such a conventional structure, it is possible to reduce the problems of rust and fretting wear that occur on the axial outer surface of the sliding contact ring and the axial inner surface of the rotating flange. However, with long-term use, the sealing seal attached and fixed to the sliding contact ring wears, which may cause problems of rust and fretting wear.

For example, in Patent Documents 4 to 6, a sliding contact ring having a configuration in which the inner diameter side half is omitted is locked to the axial inner surface of the rotating side flange instead of being externally fitted and fixed to the outer peripheral surface of the hub. The structure is described. According to such a structure, since the sliding contact ring can be displaced together with the rotating side flange that is tilted by the moment force, the problems of rust and fretting wear as described above can be solved.

Japanese Unexamined Patent Publication No. 2016-80141 Japanese Unexamined Patent Publication No. 2012-56411 JP-A-2014-240679 Japanese Unexamined Patent Publication No. 2015-52350 Japanese Unexamined Patent Publication No. 2016-14446 Japanese Unexamined Patent Publication No. 2016-17567

However, in the case of the structures described in Patent Documents 4 to 6 described above, since the sliding contact ring is locked at a position far from the bearing center which is the tilt center of the rotation side flange, the displacement width in the axial direction of the sliding contact ring. Becomes larger. For this reason, the change in the tightening allowance of the seal lip that is in sliding contact with the surface of the sliding contact ring becomes large, and the sealing performance may be insufficient. Further, in order to secure a space for arranging the sliding contact ring inside the rotating flange in the axial direction, the rolling elements in the outer rows must be moved inward in the axial direction to reduce the inter-row distance of the rolling elements. Therefore, the bearing life may be shortened.

Therefore, the present inventor initially considered the structure as shown in FIG. The undisclosed sealing device 14a according to the prior invention is provided with a bellows portion 22 in the radial intermediate portion of the sliding contact ring 17a. Further, a sealing seal 23 is attached and fixed to a portion of the sliding contact ring 17a near the outer end in the radial direction. Then, the sealing seal 23 is brought into contact with the axial inner side surface of the rotating side flange 12 to provide a gap between the axial outer surface of the sliding contact ring 17a and the axial inner side surface of the rotating side flange 12. There is. According to such a structure, it is possible to suppress the occurrence of problems of rust and fretting wear on the axially outer surface of the sliding contact ring 17a and the axially inner surface of the rotating side flange 12. Further, since the outer diameter side portion of the sliding contact ring 17a with respect to the bellows portion 22 can be displaced in the axial direction with respect to the inner diameter side portion, wear of the sealing seal 23 can be suppressed. Further, by elastically deforming the sealing seal 23, the inclination angle of the outer diameter side portion of the sliding contact ring 17a can be suppressed to be smaller than the inclination angle of the rotating side flange 12, so that the sliding contact ring 17a is slid on the outer diameter side portion. The change in the tightening margin of the seal lip 21a in contact can be suppressed to a small extent, and the seal performance can be ensured.

However, it is necessary for the sliding contact ring 17a to satisfy various required performances such as having rust prevention performance and requiring a certain degree of hardness in the sliding contact portion where the tip edge of the seal lip is in sliding contact. For this reason, a stainless steel plate, which is a difficult-to-press-molded material, is often used as the metal plate used as the material for the sliding contact ring 17a. Such a stainless steel plate, such as the bellows portion 22 described above, is used. In addition, it is difficult to form a complicated shape with a large amount of bending deformation by press working.

In view of the above circumstances, the present invention has been invented to realize a structure of a rolling bearing unit capable of suppressing a change in the tightening allowance of a seal lip, facilitating the manufacture of a sliding contact ring, and ensuring a bearing life. It was done.

The rolling bearing unit of the present invention includes an outer ring, a hub, a plurality of rolling elements, and a sealing device.
Of these, the outer ring is configured to have a substantially cylindrical shape, for example, and has one or more outer ring tracks on the inner peripheral surface. For example, the outer ring is supported and fixed to a suspension device during use and does not rotate.
The hub is arranged concentrically with the outer ring on the inner diameter side of the outer ring, the inner ring track is located on the outer peripheral surface facing the outer ring track, and the rotating side is located on the outer ring portion protruding from the axial outer end opening of the outer ring. Each of them has a flange, and for example, it rotates together with the wheel in a state where the wheel is coupled and fixed to the rotating side flange during use.
Each of the rolling elements is, for example, a ball or a tapered roller, and is rotatably provided between the outer ring track and the inner ring track.
The sealing device is for closing the axial outer end opening of the internal space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub, and has a sliding contact ring and a sealing ring. There is.
Of these, the sliding contact ring is formed in an annular shape as a whole, and is externally fitted and fixed to, for example, a portion of the outer peripheral surface of the hub adjacent to the inside of the rotating flange in the axial direction, and the outer peripheral surface of the hub. And covers the axial inner surface of the rotating flange.
The seal ring is supported and fixed to the axial outer end of the outer ring, and the tip edge of the seal lip is slidably contacted with the surface of the sliding contact ring over the entire circumference.
Further, in the case of the present invention, the sliding contact ring is fitted and fixed to the outer peripheral surface of the hub, for example, a metal ring-shaped inner diameter side sliding contact element and, for example, a metal ring-shaped outer diameter side. It is configured by joining the sliding contact element with an elastic material.
When the present invention is carried out, the sealing device is further provided with a sealing seal elastically sandwiched between the axially outer surface of the sliding contact ring and the axially inner surface of the rotating flange. Can be done. In this case, the sealing seal may be provided on a part of the elastic material, or the elastic material and the sealing seal may be provided separately.

In the present invention, in the bonding mode between the inner diameter side end portion of the outer diameter side end portion of the inner diameter side sliding contact element and the outer diameter side sliding element, the outer diameter side end portion and the outside of these inner diameter side sliding contact element A configuration is adopted in which the inner diameter side end portions of the radial side sliding contact elements are arranged so as to be separated from each other, and an elastic material is interposed between them.
Further, depending on the magnitude of rigidity required for the joint (the amount of relative displacement of the outer diameter side sliding contact element with respect to the inner diameter side sliding contact element), the outer diameter side end portion and the outer diameter side of the inner diameter side sliding contact element. It is possible to change the proximity mode (positional relationship, facing relationship, distance between ends, etc.) of the sliding contact element with the inner diameter side end portion and the type of elastic material.
In the first aspect of the present invention, inside the elastic material, the outer diameter side end portion of the inner diameter side sliding contact element and the inner diameter side end portion of the outer diameter side sliding contact element are separated from each other. An annular or annular end edge provided at the end of the (for example, the axial edge of the cylindrical portion, or the outer or inner periphery of the annular portion) and the circumferential direction provided at the other end. (For example, the side surface of the annular portion, the radial side surface which is the peripheral surface of the cylindrical portion, and the radial side surface which is the peripheral surface of the conical tubular portion) are opposed to each other .
Further, when it is desired to increase the rigidity of the joint portion more than when the edge and the side surface are opposed to each other, as in the second aspect of the present invention , inside the elastic material and outside the inner diameter side sliding contact element. It is also possible to adopt a configuration in which the radial end portion and the inner diameter side end portion of the outer diameter side sliding contact element are separated from each other and the side surfaces continuous in the circumferential direction face each other.

According to the rolling bearing unit of the present invention having the above-described configuration, it is possible to suppress a change in the tightening allowance of the seal lip, facilitate the manufacture of a sliding contact ring, and secure the bearing life.

FIG. 5 is a cross-sectional view showing a rolling bearing unit showing a first example of an embodiment of the present invention. Similarly, an enlarged view of part A in FIG. The figure corresponding to the part B of FIG. 2 which also shows two examples of the modification. The figure corresponding to FIG. 2 which shows the 2nd example of the Embodiment of this invention. The figure corresponding to the part C of FIG. 4 which also shows two examples of the modification. Sectional drawing which shows the rolling bearing unit of a conventional structure. An enlarged view corresponding to part D in FIG. The figure corresponding to FIG. 2 shown for demonstrating the structure which concerns on the prior invention.

[First Example of Embodiment]
The first example of the embodiment of the present invention will be described with reference to FIGS. 1 and 2. The rolling bearing unit 1a of this example is used to rotatably support the wheels (driving wheels) of an automobile with respect to the suspension device, and includes an outer ring 2a, a hub 3a, and a plurality of rolling elements (balls). It includes 4a and 4a, a sealing device 14b, and a cover 16a.

The outer ring 2a is made of an iron-based alloy such as medium carbon steel and is formed in a substantially cylindrical shape, and has a double-row outer ring track 6c and 6d on the inner peripheral surface and a stationary side flange 5a on the outer peripheral surface, respectively. ing. At the time of use, such an outer ring 2a does not rotate while being supported by the suspension device by coupling and fixing the stationary side flange 5a to the knuckle of the suspension device (not shown).

The hub 3a is configured by connecting the hub main body 7a and the inner ring 8a, and is arranged concentrically with the outer ring 2a on the inner diameter side of the outer ring 2a. The hub body 7a is made of an iron-based alloy such as medium carbon steel, and the outer peripheral surface is subjected to a hardening heat treatment such as a high-frequency quenching treatment.

On the outer peripheral surface of the hub body 7a, a portion of the outer ring 2a that protrudes outward in the axial direction from the axial outer end opening is provided with a ring-shaped rotating side flange 12a for supporting and fixing the wheel and the disc rotor. There is. Of the rotating side flange 12a, the radial inner end portion (base end portion) is a thick wall portion 24 having a large axial thickness dimension (thickness), and the radial middle portion to the outer end portion (tip portion). Is a thin portion 25 whose thickness dimension in the axial direction is smaller than that of the thick portion 24. As a result, the strength and rigidity against the moment (swivel moment) applied from the wheel to the rotation side flange 12a during the turning or the like are secured. Further, the thick portion 24 and the thin portion 25 are made continuous by a step portion 26 provided on the inner side surface in the axial direction of the rotation side flange 12a near the inner diameter.

An inner ring track 10c having a partially arcuate cross-sectional shape is provided on a portion of the outer peripheral surface of the hub body 7a that faces the outer ring track 6c of the outer row provided on the inner peripheral surface of the outer ring 2a. Further, a cylindrical surface portion 27 is provided on a portion of the outer peripheral surface of the hub body 7a adjacent to the outer side of the inner ring track 10c in the axial direction. Further, a concave curved surface portion 28 having a partially arcuate cross-sectional shape is provided between the cylindrical surface portion 27 and the axial inner side surface of the rotation side flange 12a (thick wall portion 24). Further, a small diameter step portion 29 is provided at the axial inner end portion of the outer peripheral surface of the hub body 7a.

The inner ring 8a constituting the hub 3a together with the hub body 7a is made of high carbon chrome bearing steel such as SUJ2, has a substantially annular shape, and is subjected to heat treatment such as quenching. Further, on the outer peripheral surface of the inner ring 8a, an inner ring track 10d of an inner row having a partial arc shape is formed. Such an inner ring 8a is externally fitted and fixed to a small diameter step portion 29 provided at an axial inner end portion of the hub main body 7a by tightening. The inner end surface of the inner ring 8a is suppressed by the caulking portion 30 formed by plastically deforming the inner end portion in the axial direction of the hub body 7a outward in the radial direction. Instead of the structure in which the caulking portion 30 is formed at the axial inner end portion of the hub main body 7a, a structure in which a nut is screwed to the axial inner end portion of the hub main body can be adopted.

The rolling elements 4a and 4a were held by cages 11a and 11a in a portion between the outer ring orbit 6c and the inner ring orbit 10c in the outer row and a portion between the outer ring orbit 6d and the inner ring orbit 10d in the inner row, respectively. It is arranged so that it can roll freely in the state. Further, the rolling elements 4a and 4a are provided with a back surface combination type contact angle and an appropriate preload by utilizing the pressing force of the caulking portion 30. In the illustrated example, balls are used as rolling elements 4a and 4a, but in the case of a rolling bearing unit for supporting wheels of an automobile, which is heavy, tapered rollers can be used instead of the balls. ..

The axially both ends of the internal space (rolling element installation space) 15a existing between the inner peripheral surface of the outer ring 2a and the outer peripheral surface of the hub 3a are closed by the sealing device 14b and the cover 16a. Of these, the cover 16a closes the axial inner end opening of the outer ring 2a to close the axial inner end opening of the internal space 15a, and is generally formed in a bottomed cylindrical shape and has a cylindrical shape. It includes a support cylinder portion 31 and a bottom plate portion 32 that is bent inward in the radial direction from the axial inner end portion of the support cylinder portion 31. Then, by internally fitting and fixing the support cylinder portion 31 to the axial inner end portion of the outer ring 2a, the axial inner end opening of the internal space 15a is provided together with the axial inner side surface of the hub body 7a which is the inner body. Is blocking.

The sealing device 14b closes the axial outer end opening of the internal space 15a, and is composed of a sliding contact ring 17b, a sealing seal 46, and a sealing ring 18a.
Of these, the sliding contact ring 17b is formed in an annular shape as a whole, and the inner diameter side sliding contact element 33 and the outer diameter side sliding contact element 34, each of which is made of a metal plate having corrosion resistance such as a stainless steel plate, and their inner diameters. An elastic material 35 made of an elastic material such as rubber or synthetic resin for joining the side sliding contact element 33 and the outer diameter side sliding contact element 34 is provided.

The inner diameter side sliding contact element 33 has a substantially L-shaped cross section and is configured in an annular shape as a whole, and is a portion for positioning the entire sliding contact ring 17b in the axial direction and the radial direction, and is a cylindrical fitting cylinder portion 36. And a ring-shaped disc portion 37 that is bent at a right angle from the axial outer end portion of the fitting cylinder portion 36 toward the radial outward side. Then, the fitting cylinder portion 36 of these is externally fitted and fixed to the cylindrical surface portion 27 of the hub main body 7a by tightening to ensure positioning in the radial direction. In the case of this example, the outer peripheral surface of the fitting cylinder portion 36 and the axial inner surface of the disc portion 37 are the sliding contact surfaces of the seal lips 21f and 21e, which will be described later, respectively, and the outer diameter side end portion of the disc portion 37 is used. It is a connection portion with the outer diameter side sliding contact element 33.

The outer diameter side sliding contact element 34 has a substantially horizontal U-shape in cross section and is formed in an annular shape as a whole, and has an inner diameter dimension slightly smaller than the outer diameter dimension of the inner diameter side sliding contact element 33. Further, the outer diameter side sliding contact element 34 is arranged on the outer side in the axial direction and the outer side in the radial direction of the inner diameter side sliding contact element 33 in a state of being joined to the inner diameter side sliding contact element 33 by an elastic material 35 described later. Such an outer diameter side sliding contact element 34 has a cylindrical inner diameter side tubular portion 38 and a substantially circular ring shape provided in a state of extending radially outward from the axial outer end portion of the inner diameter side tubular portion 38. The side plate portion 39 is provided with a conical tubular (or cylindrical) outer diameter side tubular portion 40 provided in a state of being bent inward in the axial direction from the outer peripheral edge of the side plate portion 39. Further, the side plate portion 39 includes an inner diameter side annular portion 41, an inclined plate portion 42 inclined in an axially outward direction from the outer peripheral edge of the inner diameter side annular portion 41 toward the outer side in the radial direction, and an inclined plate. It is provided with an outer diameter side annular portion 43 provided so as to extend radially outward from the outer peripheral edge of the portion 42. Further, the inner diameter side annular portion 41 and the outer diameter side annular portion 43 are arranged substantially in parallel in a state of being offset in the axial direction, and the radial width dimension of the inner diameter side annular portion 41 is the outer diameter side annular portion. It is sufficiently larger than the radial width dimension of the portion 43. In the case of this example, the inner side surface of the inner diameter side circular ring portion 41 in the axial direction is the sliding contact surface of the seal lip 21d described later, and the inner diameter side cylinder portion 38 is the connecting portion with the inner diameter side sliding contact element 34.

The elastic material 35 includes a joint ring portion 44 that joins the outer diameter side end portion of the inner diameter side sliding contact element 33 and the inner diameter side end portion of the outer diameter side sliding contact element 34 so as to enable a slight relative displacement, and an inner diameter side circle. A circle elastically sandwiched between the annular covering portion 45 that covers the axial outer surface of the ring portion 41, the axial outer surface of the sliding contact ring 17b, and the axial inner surface of the rotating flange 12a. An annular sealing seal (gasket) 46 is integrally provided.

The joint ring portion 44 has a substantially cylindrical shape as a whole, and is provided at the inner diameter side end portion of the elastic material 35, and the outer diameter side end portion and the outer diameter side sliding portion of the inner diameter side sliding contact element 33 (disk portion 37). It covers the periphery of the inner diameter side end portion (inner diameter side cylinder portion 38) of the contact element 34, respectively. Further, in a state where the inner diameter side sliding contact element 33 and the outer diameter side sliding contact element 34 are joined, inside the joining ring portion 44, the shaft of the inner diameter side cylinder portion 38 corresponding to the end edge described in the claims. The inner edge in the direction and the outer diameter side end of the outer surface in the axial direction of the disk portion 37 corresponding to the side surface described in the claims are close to each other in the axial direction over the entire circumference. As a result, the disk portion 37 and the inner diameter side cylinder portion 38 are superposed in the axial direction. Then, with respect to the elastic material 35 existing between the outer diameter side end portion of the inner diameter side sliding contact element 33 and the inner diameter side end portion of the outer diameter side sliding contact element 34, the inner diameter side sliding contact element 33 , The axial outer surface of the disk portion 37 having high adhesiveness to rubber is joined, and the outer diameter side sliding contact element 34 has an inner diameter having low adhesiveness to rubber due to the fracture surface. The axial inner edge of the side cylinder 38 is joined. Further, in the case of this example, when the elastic material 35 is vulcanized, the outer diameter side portion of the inner diameter side sliding contact element 33 and the inner diameter side of the outer diameter side sliding contact element 34 are inside the joint ring portion 44. By adhering and fixing the portion via the elastic material 35, the sliding contact ring 17b in which the inner diameter side sliding contact element 33 and the outer diameter side sliding contact element 34 are joined by the elastic material 35 (joining ring portion 44) is formed. obtain.

The sealing seal 46 has a triangular cross section, and is provided on the outer diameter side end portion of the covering portion 45 over the entire circumference in a state of projecting outward in the axial direction. Note that FIG. 2 and FIG. 4 described later show the shape of the sealing seal 46 in the free state.

In a state where the sliding contact ring 17b having the above-described configuration is assembled to the hub main body 7a, the sliding contact ring 17b is formed on the outer peripheral surface (cylindrical surface portion 27, concave curved surface portion 28) and the rotation side flange 12a ( Axial inner side surfaces of the thick portion 24, the step portion 26, and the inner diameter side end portion of the thin wall portion 25) are covered, and the sealing seal 46 is outside the axial direction of the inner diameter side annular portion 41 of the outer diameter side sliding contact element 34. It is elastically sandwiched between the side surface and the inner side surface of the thick portion 24 of the rotating side flange 12a in the axial direction over the entire circumference. In this state, between the axially outer surface of the inner diameter side annular portion 41 and the axial inner surface of the thick wall portion 24, between the inner peripheral surface of the inclined plate portion 42 and the outer peripheral surface of the step portion 26, and Between the axially outer surface of the outer diameter side annular portion 43 and the axially outer surface of the thin-walled portion 25, the two sides facing each other are prevented from coming into contact with each other and causing fretting wear. A minute gap is provided for this purpose. The sealing seal 46 closes the radial outer end portion of the minute gap provided between the axial outer surface of the inner diameter side circular ring portion 41 and the axial inner surface of the thick portion 24.

Further, in order to prevent the sliding contact ring 17b from coming out from the hub body 7a inward in the axial direction, a portion of the outer peripheral surface of the hub body 7a near the inner end in the axial direction of the cylindrical surface portion 27 (the fitting cylinder portion 36 is removed). A locking step portion 47 facing outward in the axial direction is formed over the entire circumference or intermittently in a portion (a portion adjacent to the inner side in the axial direction of the fitting portion). Then, by engaging the locking step portion 47 with the inner edge of the fitting cylinder portion 36 in the axial direction, the fitting cylinder portion 36 is prevented from coming off inward in the axial direction with respect to the cylindrical surface portion 27.

The seal ring 18a is composed of a core metal 19a and a sealing material 20a.
Of these, the core metal 19a is formed in an annular shape with a substantially horizontal T-shape in cross section by punching and bending a metal plate such as a steel plate, and has a cylindrical fixed cylinder portion 48. , The outward flange portion 49 bent outward in the radial direction from the outer end in the axial direction of the fixed cylinder 48, and folded outward in the axial direction from the inner end in the axial direction of the fixed cylinder 48 and inward in the radial direction. It is provided with an inner diameter support portion 50 that is bent toward the direction. Then, the fixed cylinder portion 48 is internally fitted and fixed to the inner peripheral surface of the axially outer end portion of the outer ring 2a by tightening.

The sealing material 20a is made of an elastic material such as an elastomer such as rubber, and is bonded to the core metal 19a by vulcanization adhesion while covering the axially outer surface and the inner and outer peripheral surfaces of the core metal 19a. Such a sealing material 20a is provided with three contact-type sealing lips 21d to 21f that are in sliding contact with the surface of the sliding contact ring 17b, an outer diameter side covering portion 51, and an auxiliary lip 52.

Of the three seal lips 21d to 21f, the tip edge of the seal lip 21d provided on the outermost side in the radial direction is on the inner side surface in the axial direction of the inner diameter side annular portion 41 constituting the outer diameter side sliding contact element 34. Sliding contact. Further, the tip edge of the seal lip 21e provided in the radial intermediate portion is in sliding contact with the radial intermediate portion of the axial inner side surface of the disk portion 37 constituting the inner diameter side sliding contact element 33. Further, the tip edge of the seal lip 21f provided most radially inward is in sliding contact with the outer peripheral surface of the fitting cylinder portion 36 constituting the inner diameter side sliding contact element 33. With such a sliding contact mode, the opening at the outer end in the axial direction of the internal space 15a is closed to prevent foreign matter such as muddy water from entering the internal space 15a. Note that FIGS. 2 and 3 to 5 described later show the shapes of the seal lips 21d to 21f in the free state.

In the illustrated example, the seal lips 21d and 21e are inclined in the direction toward the external space (opposite to the internal space 15a) from the base end edge to the tip end edge, respectively. As a result, the foreign matter intrusion prevention function by the seal lips 21d and 21e is enhanced. On the other hand, the seal lip 21f is inclined in a direction toward the central side in the axial direction of the internal space 15a from the outer diameter side edge which is the base end edge toward the inner diameter side end edge which is the tip edge. As a result, the grease leakage prevention function of the seal lip 21f is enhanced.

The outer diameter side covering portion 51 is provided so as to cover the periphery (both sides in the axial direction and the outer diameter in the radial direction) of the outward flange portion 49, and the outer ring 2a has a seal ring 18a attached to the outer ring 2a. It projects radially outward from the outer peripheral surface of the outer end in the axial direction. Further, the outer peripheral surface of the outer diameter side covering portion 51 is brought close to the inner peripheral surface of the outer diameter side tubular portion 40 constituting the outer diameter side sliding contact element 34 via a minute gap. As a result, a labyrinth seal is formed between the outer peripheral surface of the outer diameter side covering portion 51 and the inner peripheral surface of the outer diameter side tubular portion 40.

The auxiliary lip 52 is provided over the entire circumference of the outer diameter side covering portion 51 at the axially intermediate portion of the axially outer surface in a state of projecting outward in the axial direction. Further, the auxiliary lip 52 is inclined outward in the radial direction toward the outer side (tip side) in the axial direction, and the tip edge thereof is on the outer diameter side constituting the outer diameter side sliding contact element 34. The annular portion 43 is brought close to the inner surface in the axial direction via a minute gap. As a result, a labyrinth seal is formed between the tip edge of the auxiliary lip 52 and the outer diameter side circular ring portion 43.

Also in the case of the rolling bearing unit 1a of this example having the above configuration, a metal plate sliding contact having corrosion resistance is used as a mating surface for sliding the tip edges of the seal lips 21d to 21f constituting the seal ring 18a. The surface of the ring 17b is adopted. For this reason, it is possible to prevent problems such as seal squeal and sticking of the seal lip, such as when the tip edge of the seal lip is slidably contacted with the surface of the hub where grinding lines are likely to occur due to the grinding process. Further, the sealing seal 46 provided on the axially outer surface of the sliding contact ring 17b (inner diameter side annular portion 41 of the outer diameter side sliding contact element 34) is elastically contacted with the axial inner side surface of the rotating side flange 12a. A minute gap is provided between the lateral outer surface of the sliding contact ring 17b and the axial inner surface of the rotating flange 12a. Therefore, it is possible to prevent problems of rust and fretting wear from occurring in the portion between the axial outer surface of the sliding contact ring 17b and the axial inner surface of the rotating flange 12a.

Further, the sealing seal 46 closes a minute gap between the axially outer surface of the inner diameter side circular ring portion 41 of the outer diameter side sliding contact element 34 and the axial inner surface of the thick portion 24 of the rotating side flange 12a. Therefore, it is possible to prevent the grease in the internal space 15a from leaking to the external space and foreign matter such as rainwater and muddy water from entering the internal space 15a from the external space through the minute gaps. Further, since it is possible to prevent water from entering the space between the surface of the sliding contact ring 17b and the surface of the hub body 7a, the material of the sliding contact ring 17b (stainless steel) and the material of the hub body 7a (carbon steel) are used. It is also possible to prevent the occurrence of electrolytic corrosion due to the standard electrode potential difference between the two. Further, since the labyrinth seal is formed on the outer side (external space side) in the radial direction from the seal lip 21d provided on the outermost side in the radial direction, foreign matter such as muddy water splashed up from the road surface enters the seal lip 21d. The amount reached is kept small.

In particular, in the case of this example, the sliding contact ring 17b has a two-divided structure of an inner diameter side sliding contact element 33 and an outer diameter side sliding contact element 34, and the outer diameter side end portion and the outer diameter side of these inner diameter side sliding contact elements 33. A configuration is adopted in which the inner diameter side end portion of the diameter side sliding contact element 34 is joined by the joining ring portion 44 of the elastic material 35. Therefore, with the inner diameter side sliding contact element 33 fitted and fixed to the hub body 7a, the outer diameter side sliding contact element 34 is attached to the inner diameter side sliding contact element 33 by utilizing the elastic deformation of the joint ring portion 44. It is possible to make a slight relative displacement in the axial direction and to make a swing displacement (swinging motion). Therefore, when the rotating side flange 12a is tilted by the moment force based on the road surface reaction force, the outer diameter side sliding contact element 34 is transferred to the inner diameter side sliding contact element 33 via the sealing seal 46 pressed by the rotating side flange 12a. Relative displacement and swing displacement (retract) can be performed inward in the axial direction. Therefore, it is possible to prevent the sealing seal 46 from being strongly sandwiched between the axial inner surface of the rotating side flange 12a and the axial outer surface of the outer diameter side sliding contact element 34, and the wear of the sealing seal 46 can be suppressed. You can plan. Further, since the sealing seal 46 can be elastically deformed (compressively deformed) in the axial direction, the inclination angle of the outer diameter side sliding contact element 34 can be suppressed to be smaller than the inclination angle of the rotation side flange 12a. Therefore, the change in the tightening allowance of the seal lip 21d whose tip edge is slidably contacted with the inner side surface in the axial direction of the outer diameter side sliding contact element 34 can be suppressed to be small, and the sealing performance by the seal lip 21d can be ensured.

Further, the sliding contact ring 17b having the above-mentioned structure is formed by pressing a stainless steel plate to form an inner diameter side sliding contact element 33 having an L-shaped cross section and having no bellows portion as in the structure according to the above-mentioned prior invention. After forming the outer diameter side sliding contact element 34 having a substantially horizontal U-shaped cross section, the outer diameter side end portion of the inner diameter side sliding contact element 33 and the inner diameter side end portion of the outer diameter side sliding contact element 34 are formed. At the time of vulcanization molding of the elastic material 35, it can be easily manufactured by adhering through the elastic material 35. Further, in the case of this example, the sliding contact ring 17b is externally fitted and fixed to the outer peripheral surface of the hub body 7a, and it is not necessary to lock the sliding contact ring 17b to the axial inner surface of the rotating side flange 12a. The distance between rows can be secured, and the bearing life can be secured.

In the case of carrying out this example, for example, instead of the structure in which the sealing seal 46 is provided on a part of the elastic material 35, for example, on the inner side surface in the axial direction of the thick portion (or thin portion) of the rotary side flange. An annular recess may be formed, and a structure may be adopted in which an O-ring, which is a sealing seal, is sandwiched between the annular recess and the axially outer surface of the inner diameter side annular portion (or outer diameter side annular portion). .. Further, the shape of the sealing seal provided on the lateral outer surface of the sliding contact ring can be appropriately changed according to the usage mode of the rolling bearing unit and the like. Further, instead of the structure in which the locking step portion 47 is provided on the cylindrical surface portion 27 of the hub body 7a, a locking recess or a locking projection is provided on the cylindrical surface portion over the entire circumference or intermittently, and these locking recesses and locking are provided. A structure may be adopted in which the axial inner end of the sliding contact ring is locked to the protrusion.

Two modified examples of this embodiment will be described with reference to FIG.
In the first example of the embodiment, as shown in FIG. 2, the axial inner edge of the inner diameter side cylinder 38 and the outer diameter side end of the axial outer surface of the disk 37 are close to each other in the axial direction. The inner diameter side sliding contact element 33 and the outer diameter side sliding contact element 34 are joined by adhesively fixing the inner diameter side sliding contact element 33 through the elastic material 35 by the joining ring portion 44 in a state of facing each other. Then, the outer peripheral surface of the inner diameter side tubular portion 38 and the outer peripheral edge of the disc portion 37 are set to substantially the same radial position. When the rigidity of the joint portion between the inner diameter side sliding contact element 33 and the outer diameter side sliding contact element 34 is set to the same level as that of the first example of the above embodiment, for example, it is shown in FIG. 3A. As in the first example of the modified example, inside the joint ring portion 44, the axial inner end portion of the inner peripheral surface of the inner diameter side tubular portion 38 and the outer peripheral edge of the disc portion 37 are brought close to each other in the radial direction ( A configuration (superposed in the radial direction via the elastic material 35) may be adopted. In the structure of the first example of the modified example, the axial inner edge of the inner diameter side tubular portion 38 and the axial inner side surface of the disk portion 37 are substantially the same axial position.
In the structure of the first example of the modified example, the outer peripheral edge of the disk portion 37 corresponds to the edge described in the claims, and the radial inner surface surface which is the inner peripheral surface of the inner diameter side cylinder portion 38 is , Corresponds to the aspect described in the claims.

When it is desired to increase the relative displacement of the outer diameter side sliding contact element 34 with respect to the inner diameter side sliding contact element 33 as compared with the structures of the first example and the first modification of the modified example, the inner diameter side sliding contact element It is conceivable to reduce the rigidity of the joint portion between the 33 and the outer diameter side sliding contact element 34. In order to reduce the rigidity of the joint portion, for example, the edge of the inner diameter side sliding contact element 33 and the outer diameter side sliding contact element 34 has a fracture surface formed by press working, and is adhered to the elastic material 35 (joint ring portion 44). You can take advantage of the fact that the force is lower than the other parts. When the rigidity is lowered from such a viewpoint, although it is out of the technical range of the present invention, for example, as in the second example of the modified example shown in FIG. 3B, the disk portion 37 and the inner diameter side cylinder By not superimposing the portion 38 on either the axial direction or the radial direction and bringing the outer peripheral edge of the disk portion 37 and the axial inner edge of the inner diameter side tubular portion 38 close to each other, the inner diameter side sliding contact element 33 The elastic material 35 existing between the outer diameter side sliding contact element 34 and the outer diameter side sliding contact element 34 is joined to the outer peripheral edge of the disk portion 37 and the axial inner end edge of the inner diameter side cylinder portion 38, each of which has a fracture surface. The configuration can be adopted.
In this way, in the case of this example, the positional relationship between the outer diameter side end of the inner diameter side sliding contact element 33 and the inner diameter side end of the outer diameter side sliding contact element 34 is adjusted with respect to the elastic material 35. The adhesive force is changed, or the thickness of the elastic material 35 existing between the outer diameter side end of the inner diameter side sliding contact element 33 and the inner diameter side end of the outer diameter side sliding contact element 34 is changed. Therefore, the magnitude of the rigidity of the joint portion between the inner diameter side sliding contact element 33 and the outer diameter side sliding contact element 34 can be appropriately adjusted.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIG. In the case of the sealing device 14c of this example, the rigidity of the joint portion between the inner diameter side sliding contact element 33a and the outer diameter side sliding contact element 34 constituting the sliding contact ring 17c is determined by the structure of the first example of the above embodiment. It is higher than the case of.

For this reason, the inner diameter side sliding contact element 33a has a substantially crank-shaped cross section, and is bent at a right angle from the cylindrical fitting cylinder portion 36 and the axially outer end portion of the fitting cylinder portion 36 toward the outside in the radial direction. It is assumed that the disk portion 37 is provided with a cylindrical portion 53 for joining, which is bent outward in the axial direction from the outer peripheral edge of the disk portion 37. Further, the axial dimension of the joining cylindrical portion 53 is substantially the same as the axial dimension of the inner diameter side cylindrical portion 38 constituting the outer diameter side sliding contact element 34.

Then, the radial inner side surface (inner peripheral surface) of the joining cylindrical portion 53 constituting the inner diameter side sliding contact element 33a and the outer diameter side sliding contact element 34, each of which corresponds to the side surface described in the claims, are provided. In a state where the radial outer surface (outer peripheral surface) of the inner diameter side tubular portion 38 to be formed is close to each other in the radial direction over the entire circumference, the circumferences of the joining cylindrical portion 53 and the inner diameter side tubular portion 38 are elastic. It is covered with a joint ring portion 44a of the material 35a. Further, in the case of this example, the inner side surface of the inner ring portion 41 in the axial direction and the outer edge of the cylindrical portion 53 for joining in the axial direction are brought close to each other in the axial direction, and are opposed to the outer surface in the axial direction of the disk portion 37. The inner edge of the inner diameter side cylindrical portion 38 in the axial direction is brought close to each other in the axial direction. That is, the outer diameter side end portion of the inner diameter side sliding contact element 33a and the inner diameter side end portion of the outer diameter side sliding contact element 34 are joined by the joining ring portion 44a in a state of being superimposed in the radial direction and the axial direction. There is. Therefore, the inner diameter side sliding contact element 33a and the outer diameter are relative to the elastic material 35a existing between the outer diameter side end portion of the inner diameter side sliding contact element 33a and the inner diameter side end portion of the outer diameter side sliding contact element 34. Each of the side sliding contact elements 34 is joined to a surface having high adhesiveness (the radial inner surface of the joining cylindrical portion 53 and the radial outer surface of the inner diameter side tubular portion 38).

In the case of this example having the above configuration, the rigidity of the joint portion between the inner diameter side sliding contact element 33a and the outer diameter side sliding contact element 34 can be increased as compared with the case of the first example of the embodiment. ..
Further, in the case of carrying out this example, a plurality of notches or through holes are provided in either or both of the joining cylindrical portion 53 and the inner diameter side cylindrical portion 38 at equal intervals in the circumferential direction. It can be installed at the position. With such a configuration, the rigidity of the joint portion between the inner diameter side sliding contact element 33a and the outer diameter side sliding contact element 34 can be adjusted, and the adhesiveness with the rubber can be further improved. Further, when the bonded ring portion 44a is vulcanized and molded, the fluidity of the rubber can be improved.
Other configurations and effects are the same as in the case of the first example of the above-described embodiment.

Two modified examples of this embodiment will be described with reference to FIG.
In the second example of the embodiment, as shown in FIG. 4, in order to secure the rigidity of the joint portion between the inner diameter side sliding contact element 33a and the outer diameter side sliding contact element 34, inside the joint ring portion 44a. The radial outer surface of the inner diameter side tubular portion 38 and the radial inner surface of the joining cylindrical portion 53 are brought close to each other in the radial direction.
However, in order to give the joint portion the same degree of rigidity, the facing direction between the outer diameter side end of the inner diameter side sliding contact element and the inner diameter side end of the outer diameter side sliding contact element is not limited to the radial direction. It can be appropriately changed according to the configuration of the seal ring used together with the sliding contact ring and the shape of the outer peripheral surface of the hub body (for example, the size of the radius of curvature of the concave curved surface portion 28).

For example, as in the third example of the modified example shown in FIG. 5 (A), the outer diameter side sliding contact element 34a is joined to the inner diameter side tubular portion 38 by bending inward from the axial inner edge. The ring portion 54 is provided, and inside the joining ring portion 44b, the axial inner surface of the joining ring portion 54 and the axial outer surface of the disk portion 37 constituting the inner diameter side sliding contact element 33 are pivoted. It can be made close to each other in the direction.
In the case of the structure of the third example of such a modified example, the axial outer surface of the disk portion 37 and the axial inner surface of the joining ring portion 54 correspond to the side surfaces described in the claims. ..

Alternatively, as in the fourth example of the modified example shown in FIG. 5B, the inner peripheral side sliding contact element 33b is axially outward as it goes outward in the radial direction from the outer peripheral edge of the disc portion 37. A conical cylinder portion 55 for joining is provided which is inclined in the direction, and the inner diameter side cylinder portion 38a constituting the outer diameter side sliding contact element 34b is inclined inward in the radial direction so as to be inward in the axial direction for joining. Inside the ring portion 44c, the radial inner surface (inner peripheral surface) of the conical conical cylinder portion 55 for joining and the radial outer surface (outer peripheral surface) of the inner diameter side cylinder portion 38a can be obliquely opposed to each other.
In the case of the structure of the fourth example of such a modification, the radial inner surface of the conical cylinder portion 55 for joining and the radial outer surface of the inner diameter side cylinder portion 33a correspond to the side surfaces described in the claims. To do.

The present invention is not limited to the rolling bearing unit for the driven wheel for rotatably supporting the driven wheel as shown in FIG. 1, but the rolling bearing unit for the driving wheel for rotatably supporting the driving wheel. Can be applied to. Further, when the present invention is carried out, the structure of the sliding contact ring is not limited to the structure of each example of the above-described embodiment, and the inner diameter side sliding contact element, the outer diameter side sliding contact element, and the elastic material are used. The shape can be appropriately changed according to the shape of the seal ring used in combination, the shape of the hub, and the like. Further, the structure of the seal ring constituting the sealing device together with the sliding contact ring is not limited to the structure of each example of the above-described embodiment, and various structures can be adopted. Further, the present invention can be carried out by appropriately combining the structures of the examples of the above-described embodiments.

1, 1a Rolling bearing unit 2, 2a Outer ring 3, 3a Hub 4, 4a Rolling body 5, 5a Static side flange 6a to 6d Outer ring track 7, 7a Hub body 8, 8a Inner ring 9 Nut 10a to 10d Inner ring track 11, 11a Instrument 12, 12a Rotating side flange 13 Stud 14, 14a to 14c Sealing device 15, 15a Internal space 16, 16a Cover 17, 17a to 17c Sliding contact ring 18, 18a Seal ring 19, 19a Core metal 20, 20a Seal material 21a to 21f Seal lip 22 Bellows 23 Elastic member 24 Thick wall 25 Thin wall 26 Steps 27 Cylindrical surface 28 Concave curved surface 29 Small diameter steps 30 Crimping 31 Support cylinder 32 Bottom plate 33, 33a, 33b Inner diameter side sliding contact element 34, 34a, 34b Outer diameter side sliding contact element 35, 35a Elastic material 36 Fitting cylinder part 37 Disk part 38, 38a Inner diameter side cylinder part 39 Side plate part 40 Outer diameter side cylinder part 41 Inner diameter side circular ring part 42 Inclined plate Part 43 Outer diameter side annulus 44, 44a to 44c Joint ring part 45 Cover part 46 Gasket part 47 Locking step part 48 Fixed cylinder part 49 Outward flange part 50 Inner diameter support part 51 Outer diameter side cover part 52 Auxiliary lip 53 Joining Cylindrical part for joining 54 Circular part for joining 55 Conical cylinder part for joining

Claims (2)

An outer ring that has an outer ring track on the inner peripheral surface and does not rotate even during use,
A hub having an inner ring track on the outer peripheral surface and a rotating side flange in the shape of an outward flange, which is arranged concentrically with the outer ring on the inner diameter side of the outer ring and rotates during use.
A plurality of rolling elements rotatably provided between the outer ring track and the inner ring track, and
A sealing device for closing the axial outer end opening of the internal space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub is provided.
In this sealing device, a sliding contact ring that is externally fitted and fixed to the outer peripheral surface of the hub and a sliding contact ring that is supported and fixed to the axially outer end of the outer ring, and the tip edge of the seal lip is placed on the entire circumference of the surface of the sliding contact ring. It has a seal ring that is slid over and touched.
The sliding contact ring, and fitted fixed inner diameter side sliding contact elements on the outer peripheral surface of said hub, an outer diameter side sliding element is constituted by joining an elastic material,
Inside the elastic material, the outer diameter side end of the inner diameter side sliding contact element and the inner diameter side end of the outer diameter side sliding contact element are provided at one end in a state of being separated from each other. The edge and the side surface provided at the other end face each other,
Rolling bearing unit. An outer ring that has an outer ring track on the inner peripheral surface and does not rotate even during use,
A hub having an inner ring track on the outer peripheral surface and a rotating side flange in the shape of an outward flange, which is arranged concentrically with the outer ring on the inner diameter side of the outer ring and rotates during use.
A plurality of rolling elements rotatably provided between the outer ring track and the inner ring track, and
A sealing device for closing the axial outer end opening of the internal space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub is provided.
This sealing device is supported and fixed to a sliding contact ring that is externally fitted and fixed to the outer peripheral surface of the hub and an axially outer end portion of the outer ring, and the tip edge of the seal lip is placed on the entire circumference of the surface of the sliding contact ring. It has a seal ring that is slid over and touched.
The sliding contact ring, and fitted fixed inner diameter side sliding contact elements on the outer peripheral surface of said hub, an outer diameter side sliding element is constituted by joining an elastic material,
Inside the elastic material, the outer diameter side end portion of the inner diameter side sliding contact element and the inner diameter side end portion of the outer diameter side sliding contact element are opposed to each other in a state of being separated from each other.
Rolling bearing unit.

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