JP6111740B2 - Rolling bearing unit for wheel support - Google Patents

Description

  The present invention relates to an improvement of a rolling bearing unit for supporting a wheel that is used for rotatably supporting a wheel of an automobile with respect to a suspension device. Specifically, it is intended to extend the life of a seal ring that closes the axial end opening of the rolling element installation space.

  Conventionally, wheel bearing rolling bearing units having various structures have been used to support automobile wheels on a suspension device. 8 to 10 show an example of a conventional structure of such a wheel-supporting rolling bearing unit. This wheel bearing rolling bearing unit includes an outer ring 1, a hub 2, a plurality of rolling elements 3 and 3, and a pair of seal rings 4 and 5.

  Outer ring 1 has double row outer ring raceways 6a and 6b on the inner peripheral surface and stationary flange 7 on the outer peripheral surface. In use, the outer ring 1 does not rotate while being supported by the suspension device by fixing the stationary flange 7 to a knuckle of the suspension device (not shown). The hub 2 is provided concentrically with the outer ring 1 on the inner diameter side of the outer ring 1, and a double row of inner ring raceways 8 a, a part of the outer peripheral surface facing the outer ring raceways 6 a, 6 b. Similarly, the rotation side flange 9 is provided in a portion protruding outward in the axial direction from the outer ring 1. In use, such a hub 2 rotates together with the wheel and the brake rotating member in a state where a brake rotating member such as a wheel and a disk (not shown) is supported and fixed to the rotation side flange 9. Further, since the illustrated bearing unit is for a drive wheel, a spline hole 10 for engaging a spline shaft as a drive shaft is formed in the axial direction at a central portion in the radial direction of the hub 2. Unless otherwise specified, throughout the present specification and claims, “outside” in the axial direction refers to the left side of each figure, which is the outside in the width direction of the vehicle when assembled in an automobile. On the contrary, the right side of each figure, which is the center side in the width direction of the vehicle, is referred to as “inside” in the axial direction.

  Further, a plurality of rolling elements 3 and 3 are provided between the outer ring raceways 6a and 6b and the inner ring raceways 8a and 8b so as to be freely rollable in both rows. In the example shown in the figure, balls are used as the rolling elements 3 and 3. However, in the case of a rolling bearing unit for supporting a wheel for an automobile that is heavy in weight, a tapered roller is used instead of the ball. There is also. Further, both the seal rings 4 and 5 are provided in a state of closing both axial end openings of the rolling element installation space 11 existing between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the hub 2. . The seal rings 4 and 5 prevent foreign matter such as muddy water from entering the rolling element installation space 11, and the lubricating grease sealed in the rolling element installation space 11 leaks to the outside. To prevent things.

  Further, both the seal rings 4 and 5 have the same structure as the seal rings described in FIGS. That is, the seal ring 4 on the outer side in the axial direction that closes the axially outer end opening of the rolling element installation space 11 among the seal rings 4 and 5, as shown in detail in FIG. And a sealing material 13. Of these, the cored bar 12 is made of a metal plate in an annular shape, and is fitted and fixed to the outer end of the outer ring 1 in the axial direction. The sealing material 13 is formed in an annular shape by an elastic material such as an elastomer such as rubber, and is fixedly coupled to the entire circumference of the cored bar 12. Such a sealing material 13 includes three sealing lips 14 to 16 on the outside, the middle, and the inside. Of these three seal lips 14 to 16, the outer and intermediate seal lips 14, 15 are all attached to the radially inner end of the axially inner side surface of the rotary flange 9, which is a seal sliding contact surface. It is slid over the circumference. At the same time, the tip edge of the inner seal lip 16 is a portion close to the axial outer end of the outer peripheral surface of the hub 2 (between the rotary flange 9 and the inner ring raceway 8a on the outer side in the axial direction) which is a seal sliding contact surface. Part), and is in sliding contact over the entire circumference.

  On the other hand, the axially inner seal ring 5 that closes the axially inner end opening of the rolling element installation space 11 is combined with a slinger 17 to form a combined seal ring, as shown in detail in FIG. . The slinger 17 is made of a metal plate in an annular shape as a whole, and includes a rotating side cylindrical portion 18 and a rotating side that is bent radially outward from the axial inner end edge of the rotating side cylindrical portion 18. An annular portion 19 is provided. Such a slinger 17 is supported and fixed to the hub 2 in a state in which the rotation-side cylindrical portion 18 is externally fitted to the inner end portion of the inner ring 20 constituting the hub 2 by an interference fit. In the illustrated example, an annular multipolar magnet encoder 21 (shown only in FIG. 10) constituting the rotational speed detecting device is fixed to the inner surface in the axial direction of the rotating-side annular portion 19. The seal ring 5 includes a cored bar 22 and a sealing material 23. The cored bar 22 is made of a metal plate in an annular shape. The stationary side cylindrical part 24 and a stationary side circle bent radially inward from the axial outer end edge of the stationary side cylindrical part 24. Annulus 25 is provided. Such a metal core 22 is supported and fixed to the outer ring 1 in a state in which the stationary cylindrical portion 24 is fitted into the inner end of the outer ring 1 in the axial direction by an interference fit. The sealing material 23 is formed in an annular shape by an elastic material such as an elastomer such as rubber, and is bonded and fixed to the entire circumference of the cored bar 22. Such a sealing material 23 includes three sealing lips 26 to 28 on the outer side, the middle side, and the inner side. Of these three seal lips 26 to 28, the tip edge of the outer seal lip 26 is slid over the entire circumference on the outer surface in the axial direction of the rotating-side annular portion 19 which is the seal sliding contact surface. Touching. At the same time, the leading edges of the intermediate and inner seal lips 27 and 28 are brought into sliding contact with the outer peripheral surface of the rotating-side cylindrical portion 18 which is a seal sliding contact surface over the entire circumference.

  For both the seal rings 4 and 5, the outer seal lips 14 and 26 and the intermediate seal lips 15 and 27 are externally arranged toward the front end edge from the base end edge (the rolling element is installed). It is inclined in a direction toward the opposite side of the space 11. Thereby, the foreign matter intrusion preventing function by the outer seal lips 14, 26 and the intermediate seal lips 15, 27 is enhanced. On the other hand, the inner seal lips 16 and 28 are directed toward the axially central side of the rolling element installation space 11 as they go from the outer diameter side edge as the base edge toward the inner diameter side edge as the tip edge. It is inclined to. Thereby, the grease leakage prevention function by the inner seal lips 16, 28 is enhanced.

  By the way, in the case of the rolling bearing unit for supporting a wheel as described above, the rolling element installation space 11 is changed as the temperature in the rolling element installation space 11 is changed with the change of the use environment and the operation state. The pressure inside changes. On the other hand, the inner seal lips 16, 28 constituting both the seal rings 4, 5 are provided at a position in contact with the rolling element installation space 11, that is, a position for directly receiving the pressure in the rolling element installation space 11. . For this reason, when the pressure in the rolling element installation space 11 changes, the postures of the inner seal lips 16 and 28 change elastically. In particular, in the case of the wheel support rolling bearing unit described above, the inner seal lips 16 and 28 are inclined in the direction toward the axially central side of the rolling element installation space 11 toward the tip edge, Further, a seal sliding contact surface (a portion near the outer end in the axial direction of the outer peripheral surface of the hub 2, the outer periphery of the rotating side cylindrical portion 18 constituting the slinger 17) in which the tip edges of the inner seal lips 16 and 28 are in sliding contact with each other. Surface) is a simple cylindrical surface. For this reason, when the pressure in the rolling element installation space 11 suddenly rises, as in the case of cold-starting the wheel-supporting rolling bearing unit (starting from a sufficiently low temperature), The postures of the inner seal lips 16 and 28 change elastically as shown in the order of the solid line state → the chain line state in FIGS. 11A and 11B, respectively. That is, the front end portions of the inner seal lips 16 and 28 are elastically deformed in a direction in which the angle of intersection between the inner peripheral surface and the seal slidable contact surfaces becomes smaller, and are wider than the seal slidable contact surfaces. It is in a state of being pressed by the contact area. That is, simply speaking, the tightening allowance of each of the inner seal lips 16, 28 increases. As a result, the frictional force acting on the sliding contact portion between the tip end portion of each of the inner seal lips 16 and 28 and the seal sliding contact surface increases, and the wear of the inner seal lips 16 and 28 is promoted. .

  Note that the pressure in the rolling element installation space 11 that has risen rapidly as described above is that air in the rolling element installation space 11 is then transferred from the tip of each of the seal lips 14 to 16 and 26 to 28 and the seal sliding surface. By gradually leaking to the outside through the sliding contact portion, the pressure gradually decreases and becomes balanced with the external pressure. Along with this, the postures of the inner seal lips 16 and 28 are also gradually restored elastically. As a result, the sliding contact between the front end portions of the inner seal lips 16 and 28 and the seal sliding contact surfaces is achieved. The state gradually returns to the original sliding contact state (solid line state in FIGS. 11A and 11B). However, since the sliding contact state changes from the solid line state of the figure to the chain line state and then returns to the solid line state again, the tightening allowance of each of the inner seal lips 16, 28 continues, The frictional force acting on the sliding contact portion between the front end portion of each of the inner seal lips 16 and 28 and the seal sliding contact surface increases, resulting in a decrease in fuel consumption and the reduction of the fuel consumption of the inner seal lips 16 and 28. By promoting the wear, the life of each of the inner seal lips 16, 28 is reduced.

JP 2005-16603 A

  In the present invention, in view of the circumstances as described above, the tightening margin of the inner seal lip constituting the seal ring that closes the axial end opening of the rolling element installation space increases as the pressure in the rolling element installation space increases. The present invention was invented to realize a structure that can suppress the extent to which it is performed.

The wheel bearing rolling bearing unit of the present invention includes an outer ring, a hub, a plurality of rolling elements, and a seal ring.
Among these, the outer ring has a double row outer ring raceway on the inner peripheral surface, and does not rotate while being supported and fixed to the suspension device during use.
The hub is provided concentrically with the outer ring on the inner diameter side of the outer ring, and a double row of inner ring raceways are formed on the outer peripheral surface of the outer ring facing the outer ring raceways. Respective rotation side flanges are provided in portions protruding outward in the axial direction. And it rotates with this wheel in the state which supported and fixed the wheel to this rotation side flange at the time of use.
A plurality of rolling elements are provided between the outer ring raceways and the inner ring raceways so as to roll freely.
Further, the seal ring closes the axial end opening of the rolling element installation space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub. The seal ring includes an annular metal core fixed to the axial end of the outer ring, and a seal material fixed to the entire circumference of the metal core. Further, the seal material includes a plurality of seal lips, and the sliding edges of the plurality of seal lips are provided on the surface of the hub or another member fixed to the hub, respectively. In addition, they are in sliding contact over the entire circumference. Further, the plurality among the seal lip, the inner sealing lip a sealing lip which is disposed at a position that comes into contact with the rolling element installation space, the inner diameter side, a leading edge from the outer diameter edge is proximal edge It is made to incline in the direction which goes to the axial direction center side of the said rolling element installation space, so that it goes to an edge.
In particular, in the rolling bearing unit for supporting a wheel according to the present invention, a portion of the seal sliding surface where the tip edge of the inner seal lip is slidably contacted is opposite to the rolling element installation space in the axial direction. Hodogai diameter toward is an inclined surface inclined in the small AMS1.
Further, at the axial position where the sliding contact portion of the inner seal lip exists with respect to the inclined surface, the inclination angle of the tangent of the inclined surface with respect to the central axis of the hub is such that the inner seal with respect to the central axis of the hub It is smaller than the inclination angle of the tangent to the swing locus surface of the tip edge of the inner seal lip with the base edge of the lip as the center.
Further, the inner diameter of the seal lip other than the inner seal lip is equal to the inner diameter of the inner seal lip in a state where the plurality of seal lips are elastically bent toward the outer diameter around the respective base end edges. More than the dimensions.
Of the peripheral surface provided with the inclined surface, the inner seal lip is located on the center side in the axial direction of the rolling element installation space with respect to the inclined surface and is larger than the sliding contact portion. The outer diameter dimension of the portion that has become the diameter is D _A, and the diameter dimension of the bottom of the concave groove provided on the base end edge of the side surface of the inner seal lip on the rolling element installation space side is D _B , and the inner seal When the thickness dimension of the lip is t, the relationship D _A ≦ D _B −4 · t is established.

  When the rolling bearing unit for supporting a wheel of the present invention as described above is implemented, for example, the configuration of the invention described in claim 2 can be adopted as a more specific configuration. That is, when the configuration is adopted, a combination of the seal ring and the inclined surface is provided in the axially outer end opening portion of the rolling element installation space. The inclined surface is directly formed in a portion of the outer peripheral surface of the hub in the axial direction and sandwiched between the rotation-side flange and the inner ring raceway on the outer side in the axial direction.

  Moreover, when implementing this invention, the structure of the invention described in Claim 3 can also be employ | adopted as a more concrete structure, for example. That is, when the configuration is adopted, a combination of the seal ring and the inclined surface is provided in the axially outer end opening portion of the rolling element installation space. And, this inclined surface is externally fitted and fixed to a portion sandwiched between the rotation side flange and the inner ring raceway on the outer side in the axial direction of a part of the outer peripheral surface of the hub in the axial direction. It is formed on the outer peripheral surface of an annular sliding contact ring made of metal.

  Moreover, when implementing this invention, the structure of the invention described in Claim 4 can also be employ | adopted as a more concrete structure, for example. That is, when the configuration is adopted, a combination of the seal ring and the inclined surface is provided in the axially inner end opening portion of the rolling element installation space. And this inclined surface is provided in a part of metal and annular | circular shaped slinger fixed to the said hub. Specifically, the slinger is a rotation-side cylindrical portion that is externally fitted and fixed to the hub, a rotation-side annular portion that is bent radially outward from the axial inner end edge of the rotation-side cylindrical portion, An inclined plate portion that is formed in a part in the axial direction of the rotation-side cylindrical portion and is inclined in the same direction as the inclined surface is provided. And let the outer peripheral surface of this inclination board part be the said inclination surface.

  According to the rolling bearing unit for supporting a wheel of the present invention configured as described above, the extent to which the tightening margin of the inner seal lip constituting the seal ring increases as the pressure in the rolling element installation space increases can be suppressed. That is, in the case of the present invention, when the pressure in the rolling element installation space rises, under the influence, the posture of the inner seal lip changes elastically, and the leading edge of the inner seal lip, The sliding contact position with the inclined surface which is the seal sliding surface moves to the small diameter side of the inclined surface. As a result, it is possible to suppress the tip end portion of the inner seal lip from being elastically deformed in the direction along the inclined surface. For this reason, it is possible to suppress an increase in the tightening margin of the inner seal lip. Therefore, an increase in the frictional force acting on the sliding contact portion between the tip end portion of the inner seal lip and the inclined surface can be suppressed, and fuel efficiency can be improved correspondingly. At the same time, promotion of wear of the inner seal lip can be suppressed, and the life of the inner seal lip can be extended accordingly.

  Further, in the case of the invention described in claims 2 to 3, in order to assemble a rolling bearing unit for supporting a wheel, in the case of the hub (in the case of the invention described in claim 3), around the hub In the state where the outer ring to which the seal ring for closing the axial outer end opening of the rolling element installation space is fixed is disposed, the relationship between the inner seal lip constituting the seal ring and the inclined surface which is the seal sliding contact surface Therefore, it is possible to prevent the outer ring from inadvertently coming out from the periphery of the hub inward in the axial direction. For this reason, it is possible to facilitate the assembly work of the wheel bearing rolling bearing unit.

  Further, in the case of the invention described in claim 4, in the state where the seal ring and the slinger combined to seal the axially inner end opening of the rolling element installation space are combined, the seal ring is configured. The seal ring and the slinger can be prevented from being inadvertently separated in the axial direction on the basis of the engagement between the inner seal lip and the inclined surface that is the seal sliding contact surface provided on a part of the slinger. . For this reason, in order to assemble the rolling bearing unit for supporting the wheel, the work of mounting the combination seal ring on the axially inner end opening portion of the rolling element installation space can be easily performed. Therefore, it is possible to facilitate the assembly work of the wheel bearing rolling bearing unit.

The enlarged view equivalent to the a section of Drawing 8 showing the 1st example of an embodiment of the invention. The enlarged view equivalent to the b section. The enlarged view which shows the sliding contact part of the front-end edge of an inner side seal lip, and a seal sliding contact surface in the state before and behind the pressure in a rolling element installation space regarding the 1st example of embodiment. The figure similar to FIG. 1 which shows the 2nd example of embodiment of this invention. The figure similar to FIG. 1 which shows the 3rd example. The figure similar to FIG. 1 which shows the 4th example. The figure similar to FIG. 2 which shows the 5th example. Sectional drawing which shows one example of the conventional structure of the rolling bearing unit for wheel support used as the object of this invention. The a section enlarged view of FIG. The b section enlarged view. The enlarged view which shows the sliding contact part of the front-end edge of an inner side seal lip, and a seal sliding contact surface in the state before and behind the pressure in a rolling element installation space regarding one example of a conventional structure.

[First example of embodiment]
1 to 3 show a first example of an embodiment of the present invention. The feature of this example is the structure of the seal sliding contact surface for slidingly contacting the front end edges of the inner seal lips 16 and 28 constituting the pair of seal rings 4 and 5 that block the opening in the axial direction of the rolling element installation space 11. Is in the point which devised. Since the structure and operation of other parts are the same as those of the example of the conventional structure shown in FIGS. 8 to 10 described above, the same parts are denoted by the same reference numerals, and overlapping illustrations and explanations are omitted. In the following, the description will be focused on the characteristic portions of this example.

In the case of this example, as shown in FIG. 1, the axially intermediate portion of the portion between the rotation side flange 9 and the axially outer inner ring raceway 8a is partially axially outer { The side away from the axial center of the rolling element installation space 11 . In other words, the outer inclined surface 29 having a concave arc-shaped cross section is inclined in a direction in which the outer diameter becomes smaller toward the opposite side of the rolling element installation space 11 (left side in FIG. 1)} with respect to the axial direction . Yes. The outer inclined surface 29 is slidably contacted with the tip end edge of the inner seal lip 16 constituting the axially outer seal ring 4 that closes the axially outer end opening of the rolling element installation space 11. It is said. A chain line X in FIG. 1 indicates a rocking locus surface (annular surface having a concave arcuate cross section) of the distal end edge of the inner seal lip 16 centered on the proximal end edge of the inner seal lip 16. Yes. In the case of this example, the inclination angle of the outer inclined surface 29 with respect to the central axis of the hub 2a is also made smaller than the inclination angle of the swing locus surface X.

  Further, in the case of this example, the outer peripheral surface of the shoulder portion 30 existing at a position adjacent to the outer side in the axial direction of the inner ring raceway 8a on the outer side in the axial direction is a part of the hub 2a. It is an annular surface having a convex arc shape in cross section in which the axial end edges of the surface 29 are smoothly continuous. Further, in the case of this example, the outer peripheral surface of the shoulder portion 30 is sealed with the outer peripheral surface of the hub 2a so that the front end edges of the seal lips 14 to 16 constituting the seal ring 4 are in sliding contact with each other. The contact surface and the smooth surface are subjected to finishing grinding at the same time as the inner ring raceway 8a.

In the case of this example, the intermediate and inner seal lips 15 and 16 constituting the axially outer seal ring 4 are elastically bent toward the outer diameter side around the respective base end edges. The inner diameter of the intermediate seal lip 15 is configured to be equal to or larger than the inner diameter of the inner seal lip 16. This in mind, in the case of this example, the outer diameter of the shoulder portion 30 and D _30, when the outer peripheral surface (another way of the inner seal lip 16, the rolling element installation space 11 side the diameter of the bottom portion of the recessed groove 31 present in the base end edge of the side) and D _31, the thickness of the inner seal lip 16 when the t _16, "D ₃₀ ≦ D ₃₁ -2 · t ₁₆ ”(preferably“ D ₃₀ ≦ D ₃₁ −4 · t ₁₆ ”) is established so that the dimensions of the respective parts are regulated. Then, by performing such dimensional regulation, each of the intermediate and inner seal lips 15 and 16 is elastically bent toward the outer diameter side around the respective base end edges at the time of assembly. The shoulder 30 can pass through the inner diameter side of the seal lips 15 and 16 in the axial direction. In the case of this example, with respect to the axial outer side of the seal ring 4, the outer diameter D ₃₀ is equivalent to the outer diameter dimension D _A as set forth in the appended claims, the diameter D ₃₁ is, patent corresponds to the diameter D _B as set forth in the appended claims, the thickness t ₁₆ corresponds to the thickness dimensions set forth in the appended claims to t.

  In the case of this example, as shown in FIG. 2, the axially outer end portion of the rotating side cylindrical portion 18a constituting the slinger 17a is a partially conical cylinder whose outer axial end edge is the large diameter side edge. The inclined plate portion 32 is formed in a shape. Then, the outer peripheral surface of the inclined plate portion 32 is inclined in a direction in which the outer diameter dimension decreases toward the inner side in the axial direction {the side away from the axial center of the rolling element installation space 11 (right side in Fig. 2)}. A partial conical cylindrical inner inclined surface 33 is provided. The inner inclined surface 33 is used as a seal slidable contact surface that closes the axially inner end opening of the rolling element installation space 11 and slidably contacts the tip edge of the inner seal lip 28 that forms the axially inner seal ring 5. Yes. A chain line Y in FIG. 2 indicates a swing locus surface (annular surface having a concave arcuate cross section) of the distal end edge of the inner seal lip 28 with the base end edge of the inner seal lip 28 as the center. Yes. In the case of this example, the inclination angle of the inner inclined surface 33 with respect to the central axis of the hub 2a is also made smaller than the inclination angle of the tangent of the axially intermediate portion of the swing locus surface Y.

In the case of this example, the intermediate and inner seal lips 27 and 28 constituting the axially inner seal ring 5 are elastically bent toward the outer diameter side with the respective base end edges as the centers. The inner seal lip 27 has an inner diameter that is equal to or greater than the inner diameter of the inner seal lip 28. This in mind, in the case of this example, the outer diameter of the large-diameter edge of the inclined plate portions 32 and D _32, when the outer peripheral surface (another way of the inner seal lip 28, When the diameter dimension of the bottom of the concave groove 34 existing on the base edge of the rolling element installation space 11 side is D ₃₄ and the thickness dimension of the inner seal lip 28 is t ₂₈ , “D ₃₂ ≦ D ₃₄ −2 · t ₂₈ ”(preferably“ D ₃₂ ≦ D ₃₄ −4 · t ₂₈ ”), the dimensions of the respective parts are regulated. Then, by performing such dimensional regulation, each of the intermediate and inner seal lips 27, 28 is elastically bent toward the outer diameter side around the respective base end edges at the time of assembly. The large-diameter side end edge of the inclined plate portion 32 can pass through the inner diameter side of the seal lips 27 and 28 in the axial direction. In the case of this example, with respect to the axial inner side of the seal ring 5, the outer diameter D ₃₂ is equivalent to the outer diameter dimension D _A as set forth in the appended claims, the diameter D ₃₄ is, patent corresponds to the diameter D _B as set forth in the appended claims, the thickness t ₂₈ corresponds to the thickness dimensions set forth in the appended claims to t.

  According to the wheel support rolling bearing unit of the present example configured as described above, the tightening margin of the inner seal lips 16 and 28 constituting the both seal rings 4 and 5 increases the pressure in the rolling element installation space 11. The degree of increase accompanying this can be suppressed. That is, in the case of this example, the outer and inner inclined surfaces 29 and 33, which are in sliding contact with the inner edges of the inner seal lips 16 and 28, are separated from the axial center of the rolling element installation space 11, respectively. The outer diameter is inclined in the direction of decreasing toward the side. For this reason, when the pressure in the rolling element installation space 11 is increased, the inner seal lips 16, 28 are affected by the angle between the inner peripheral surface of the tip and the central axis of the bearing unit. 3A and 3B, the sliding contact positions of the leading edges of the inner seal lips 16 and 28 and the outer and inner inclined surfaces 29 and 33 are changed in accordance with the elastic change in the direction in which As shown in the order of the solid line state → chain line state in (B), the outer and inner inclined surfaces 29 and 33 move to the smaller diameter side. As a result, it is possible to prevent the tip end portions of the inner seal lips 16 and 28 from elastically deforming in the direction along the outer and inner inclined surfaces 29 and 33. Can be prevented from increasing. Therefore, it is possible to suppress an increase in the frictional force acting on the sliding contact portions between the tip portions of the inner seal lips 16 and 28 and the outer and inner inclined surfaces 29 and 33, thereby improving the fuel consumption accordingly. . At the same time, the promotion of wear of the inner seal lips 16, 28 can be suppressed, and the life of the inner seal lips 16, 28 can be extended accordingly.

In the case of this example, in order to assemble a rolling bearing unit for supporting a wheel, the seal ring 4 is configured in a state where the outer ring 1 to which the axially outer seal ring 4 is fixed is disposed around the hub 2a. Based on the engagement between the inner seal lip 16 and the outer inclined surface 29, the outer ring 1 can be prevented from inadvertently coming out from the periphery of the hub 2a inward in the axial direction. Therefore, it is possible to reduce time and effort for suppressing the hub 2a from coming out of the outer ring 1a, and the assembly work of the wheel bearing rolling bearing unit can be facilitated accordingly. Further, in the case of this example, in the assembled state of the combined seal ring, which is a combination of the axially inner seal ring 5 and the slinger 17a, the inner seal lip 28 constituting the seal ring 5 and the slinger 17a The seal ring 5 and the slinger 17a can be prevented from being inadvertently separated in the axial direction based on the engagement with the inner inclined surface 33 provided in a part of the inner surface. For this reason, in order to assemble the wheel bearing rolling bearing unit so as not to separate the seal ring 5 and the slinger 17a from being separated, the combined seal ring is provided at the axially inner end opening portion of the rolling element installation space 11. Easy to install. Therefore, it is possible to facilitate the assembling work of the wheel supporting rolling bearing unit.

  In the first example of the embodiment described above, if the swing locus surface X is employed as the outer inclined surface 29 and the swing locus surface Y is employed as the inner inclined surface 33, It is possible to almost completely prevent the sliding contact area and sliding contact pressure at the tip of each inner seal lip 16, 28 with respect to the outer and inner inclined surfaces 29, 33. In addition, the grinding process for finishing the outer peripheral surface of the hub 2a is generally performed using a general-purpose grindstone, and the inclination angle between the rotation center axes of the hub 2a and the general-purpose grindstone is set to a predetermined angle (about 30 degrees). It is performed in the state held in For this reason, when the rocking locus surface X is employed as the outer inclined surface 29, the inclination angle of the outer inclined surface 29 with respect to the rotation center axis of the total grinding wheel is increased. Accordingly, the roughness of the outer inclined surface 29 can be improved.

However, when the rocking locus surface X is used as the outer inclined surface 29, the radius of curvature of the root portion of the inner surface of the rotation side flange 9 is reduced, and stress is easily concentrated on the root portion. The strength of this root portion decreases by the amount. Furthermore, in this case, as described above, the inclination angle of the outer inclined surface 29 with respect to the rotation center axis of the overall grinding wheel is increased, so that the roughness of the outer inclined surface 29 can be improved. Grinding and grinding cracks are likely to occur on the inclined surface 29. Further, when the swing locus surface Y is adopted as the inner inclined surface 33, the outer diameter D ₃₂ of the large-diameter side edge of the inclined plate portion ₃₂ is increased, and the intermediate and inner seal lips are assembled during assembly. There is a possibility that the large-diameter side edge of the inclined plate portion 32 cannot pass in the axial direction on the inner diameter side of 27 and 28.

  Therefore, in the first example of the above-described embodiment, the inclination angle of the outer inclined surface 29 with respect to the central axis of the hub 2a is set to the same as the swing locus surface X to the extent that the inconvenience as described above does not occur. The inclination angle of the inner inclined surface 33 with respect to the central axis of the hub 2a is also made smaller than the inclination angle of the tangent at the axially intermediate portion of the swing locus surface Y.

[Second Example of Embodiment]
FIG. 4 shows a second example of the embodiment of the present invention. In the case of this example, the outer inclined surface 29a, which is in sliding contact with the tip edge of the inner seal lip 16 constituting the seal ring 4 on the outer side in the axial direction, is inclined in a direction in which the outer diameter dimension becomes smaller toward the outer side in the axial direction. In this case, the convex surface is a partially conical cylindrical shape. In addition, the outer peripheral surface of the shoulder portion 30a existing at a position adjacent to the axially outer side of the inner ring raceway 8a on the outer side in the axial direction as a part of the hub 2b is simply a cylindrical surface, and this cylindrical surface and the outer inclined surface 29a and The axial end edges of the inner ring raceway 8a are smoothly continuous. In the case of this example, the cylindrical surface that is the outer peripheral surface of the shoulder 30a is a surface that is not subjected to finishing grinding. This is because the outer peripheral surface of the shoulder portion 30a is difficult to reach the coolant (coolant) when the outer peripheral surface of the hub 2b is subjected to finishing grinding using a general-purpose grindstone. This is because it is a part that does not cause a problem even if it is not subjected to grinding work, while it is easy to cause grinding cracks.
Other configurations and operations are the same as in the case of the first example of the above-described embodiment, and thus illustrations and descriptions regarding equivalent parts are omitted.

[Third example of embodiment]
FIG. 5 shows a third example of the embodiment of the present invention. In the case of this example, the shape of the seal slidable contact surface that slidably contacts the tip edges of the seal lips 14 to 16 constituting the seal ring 4 on the outer side in the axial direction is the same as in the case of the first example (see FIG. 1). It is. However, in the case of this example, the seal sliding contact surface is provided not on the surface of the hub 2c but on the surface of the sliding contact ring 35 that is externally fitted and fixed to the hub 2c. The sliding contact ring 35 is made of a metal plate in an annular shape as a whole, and includes a fitting tube portion 36 having an outer inclined surface 29 on the outer peripheral surface, an annular portion 37, and the fitting tube portion 36. A continuous portion 38 having an arc-shaped cross section is provided that smoothly connects the outer edge in the axial direction and the inner peripheral edge of the annular portion 37. Of these, the fitting cylinder portion 36 is a part of the outer peripheral surface of the hub 2c in the axial direction, and is externally fixed by an interference fit between the rotation side flange 9 and the inner ring raceway 8a on the outer side in the axial direction. The annular portion 37 is attached to the radially inner end of the axially inner side surface of the rotating flange 9.

  In the case of this example, by increasing the outer diameter dimension of the annular portion 37 to the same extent as the outer diameter dimension of the outer end portion of the outer ring 1 in the axial direction, the axial direction of the annular portion 37 is increased. The radially outer end portion of the inner side surface is a mating surface facing the axially outer end surface of the outer ring 1. As a result, the axial width of the labyrinth gap existing between the mating surface and the axially outer end surface of the outer ring 1 is narrower than when the mating surface is the axially inner surface of the rotating flange 9. I am trying to do it. Further, in the case of this example, a sealing agent 39 such as water-resistant grease, caulking agent or the like is formed in a gap portion existing between the inner peripheral surface of the fitting cylindrical portion 36 and the continuous portion 38 and the surface of the hub 2c. Filled. This prevents foreign matter such as rainwater and muddy water from entering the rolling element installation space 11 from the outside through the portion between the sliding contact ring 35 and the hub 2c.

In the case of the rolling bearing unit for supporting a wheel of the present example configured as described above, a portion between the rotation side flange 9 and the inner ring raceway 8a on the outer side in the axial direction is a part of the outer peripheral surface of the hub 2c in the axial direction. Can be a simple cylindrical surface similar to the conventional structure. For this reason, this portion can be ground without difficulty simultaneously with the inner ring raceway 8a on the outer side in the axial direction.
Other configurations and operations are the same as in the case of the first example of the above-described embodiment, and thus illustrations and descriptions regarding equivalent parts are omitted.

[Fourth Example of Embodiment]
FIG. 6 shows a fourth example of the embodiment of the present invention. In the case of this example, the outer diameter dimension of the annular ring portion 37a constituting the sliding contact ring 35a is made smaller than the inner diameter dimension of the outer end portion in the axial direction of the outer ring 1. Thereby, the axial inner surface of the rotation side flange 9 is directly opposed to the axial outer end surface of the outer ring 1. In particular, in the case of this example, a portion closer to the radially inner end, which is a portion opposed to the axially outer end surface of the outer ring 1, out of the axially inner side surface of the rotation side flange 9, the circular ring portion 37a is formed. The protruding portion 40 protrudes inward in the axial direction from the radially inner end that is a portion to be attached. Then, by bringing the axial inner surface of the rotating flange 9 closer to the axial outer end surface of the outer ring 1 by the axial height of the protruding portion 40, the labyrinth gap existing between these both surfaces is reduced. The axial width is narrowed. Further, by making the axial height of the protruding portion 40 larger than the thickness of the annular portion 37a, rainwater, muddy water, etc. that have passed through the labyrinth gap are allowed to flow into the rotating flange 9 and the annular portion 37a. It makes it difficult to hit directly the opening of the gap existing between the two. Further, an inclined surface 41 is provided on the inner peripheral portion of the projecting portion 40. The inclined surface 41 is inclined toward the outer side in the axial direction toward the inner diameter side. As a result, a portion of the surface of the hub 2d where the annular ring portion 37a of the slidable contact ring 35a is attached, a portion where the fitting cylinder portion 36 of the slidable contact ring 35a is externally fitted, and an axially outer inner ring When the grindstone that simultaneously grinds the track 8a enters the upper left direction of FIG. 6 from the upper right direction to the lower left direction, it can be prevented from colliding with the inner peripheral portion of the protrusion 40.

Further, in the case of this example, an elastomer sealing material 42 such as rubber, which is fixed to the inner end in the axial direction of the fitting cylinder 36, is elastically applied to the entire outer circumference of the hub 2d. It is in contact. This prevents foreign matter such as rainwater and muddy water from entering the rolling element installation space 11 from the outside through the portion between the sliding contact ring 35a and the hub 2d.
Other configurations and operations are the same as in the case of the third example of the above-described embodiment, and thus description of equivalent parts is omitted.

[Fifth Example of Embodiment]
FIG. 7 shows a fifth example of the embodiment of the present invention. In the case of this example, the axially outer end portion of the rotation-side cylindrical portion 18b is an inclined plate portion 32a having an arcuate cross section. Then, an inner inclined surface having an arc-shaped cross section in which the inner half portion in the axial direction (the right half portion in FIG. 7) of the outer peripheral surface of the inclined plate portion 32a is inclined in a direction in which the outer diameter dimension decreases toward the inner side in the axial direction. 33a. The leading edge of the inner seal lip 28 constituting the axially inner seal ring 5a is brought into sliding contact with the inner inclined surface 33a. In the case of this example, the end edge of the intermediate seal lip 27a constituting the seal ring 5a is not the outer peripheral surface of the rotating side cylindrical portion 18b, but the outer side surface in the axial direction of the rotating side annular portion 19 (see FIG. 7 on the left side). Further, the inner diameter dimension of the intermediate seal lip 27a in the free state is larger than the outer diameter dimension of the central portion in the axial direction which is the maximum diameter portion of the inclined plate portion 32a.

In the case of the rolling bearing unit for wheel support of this example having the above-described configuration, the intermediate seal lip 27a is not elastically deformed when the combined seal ring composed of the seal ring 5a and the slinger 17b is assembled. The rotation-side cylindrical portion 18b can be inserted on the inner diameter side of the seal ring 5a. Further, the outer diameter dimension of the outer edge in the axial direction of the inclined plate portion 32a is smaller than the outer diameter dimension of the outer edge in the axial direction of the inner inclined surface 33a (the central portion in the axial direction of the inclined plate portion 32a). Therefore, the outer edge in the axial direction of the inclined plate portion 32a is not easily caught by the inner seal lip 28 when the rotary side cylindrical portion 18b is inserted into the inner diameter side of the seal ring 5a. In the case of this example also, the outer diameter of the axially outer end edge of the inner inclined surface 33a is larger than the inner diameter of the inner seal lip 28 in the free state. In the assembled state, it is possible to prevent the seal ring 5a and the slinger 17b from being carelessly separated based on the engagement between the inner inclined surface 33a and the inner seal lip 28. Therefore, the assembly work of the combination seal ring can be facilitated. In addition, the seal sliding contact surface at the front end edge of the intermediate seal lip 27a is changed from the outer peripheral surface of the rotating side cylindrical portion 18b to the outer side surface in the axial direction of the rotating side annular portion 19, so The sliding resistance when the tightening margin of the intermediate seal lip 27a with respect to the surface is set to the same size can be kept low. Therefore, it can contribute to the improvement of fuel consumption by that much.
Other configurations and operations are the same as those in the respective examples of the above-described embodiments, and thus illustrations and descriptions regarding equivalent parts are omitted.

The present invention is applicable to wheel bearing rolling bearing units having various structures that satisfy the requirements described in the claims.
For example, the present invention provides a wheel-supporting rolling bearing unit in which both ends in the axial direction of the rolling element installation space are closed with a combination seal ring, and an axial outer end opening among the axial direction both ends of the rolling element installation space. The present invention is also applicable to a wheel support rolling bearing unit for a driven wheel in which only the inner ring opening is closed by a seal ring and the axial inner end opening is closed by a cover attached to the axial inner end portion of the outer ring.
In addition, in the case of a rolling bearing unit for supporting a wheel in which both ends in the axial direction of the rolling element installation space are closed by a pair of seal rings, the leading edge of the inner seal lip constituting one of the seal rings It is also possible to make only the seal sliding contact surface that makes sliding contact with the inclined surface.

DESCRIPTION OF SYMBOLS 1 Outer ring 2, 2a-2d Hub 3 Rolling element 4 Seal ring 5, 5a Seal ring 6a, 6b Outer ring raceway 7 Stationary side flange 8a, 8b Inner ring raceway 9 Rotation side flange 10 Spline hole 11 Rolling body installation space 12 Core metal 13 Seal Material 14 Outer seal lip 15 Intermediate seal lip 16 Inner seal lip 17, 17a, 17b Slinger 18, 18a, 18b Rotating side cylindrical portion 19 Rotating side annular portion 20 Inner ring 21 Multi-pole magnet encoder 22 Core metal 23, 23a Sealing material 24 Static side cylindrical portion 25 Static side annular ring portion 26 Outer seal lip 27, 27a Intermediate seal lip 28 Inner seal lip 29, 29a Outer inclined surface 30, 30a Shoulder portion 31 Groove 32, 32a Inclined plate portion 33, 33a Inner inclined surface 34 Groove 35, 35a Sliding ring 36 Fitting cylinder 37, 3 a circular ring portion 38 continuous portion 39 sealant 40 projection 41 inclined surface 42 sealing material

Claims (4)

An outer ring that has a double-row outer ring raceway on its inner peripheral surface and does not rotate while being supported and fixed to a suspension device during use;
Concentric with the outer ring on the inner diameter side of the outer ring, a double-row inner ring raceway is rotated on a part of the outer peripheral surface facing the outer ring raceways to a part protruding outward in the axial direction from the outer ring. A hub that has a side flange, and rotates with the wheel while the wheel is supported and fixed to the rotating side flange during use,
A plurality of rolling elements provided in a freely rotatable manner between the outer ring raceways and the inner ring raceways;
A seal ring that closes the axial end opening of the rolling element installation space that exists between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub;
The seal ring includes an annular cored bar fixed to the axial end portion of the outer ring, and a sealing material fixed to the entire circumference of the cored bar. A plurality of seal lips, and the leading edges of the plurality of seal lips are slid over the entire circumference to the seal slidable contact surface provided on the surface of the hub or another member fixed to the hub. And the inner seal lip, which is a seal lip disposed at a position in contact with the rolling element installation space among the plurality of seal lips, extends from the outer edge on the base end to the tip edge. In a rolling bearing unit for supporting a wheel that is inclined in a direction toward an axially central side of the rolling element installation space as it goes toward an inner diameter side edge,
The portion of the seal sliding surface that is in sliding contact with the tip edge of the inner seal lip is an inclined surface that is inclined in a direction in which the outer diameter dimension decreases toward the opposite side of the rolling element installation space with respect to the axial direction. and,
At an axial position where the sliding contact portion of the inner seal lip is present with respect to the inclined surface, the inclination angle of the tangent of the inclined surface with respect to the central axis of the hub is such that the inclination angle of the inner seal lip with respect to the central axis of the hub. It is smaller than the inclination angle of the tangent line of the rocking locus surface of the tip edge of this inner seal lip centered on the base edge,
The inner diameter dimension of the seal lips other than the inner seal lip is equal to or larger than the inner diameter dimension of the inner seal lip in a state in which the plurality of seal lips are elastically bent toward the outer diameter centering on the respective base end edges. become,
Among the peripheral surfaces provided with the inclined surface, the inner seal lip is located on the axially central side of the rolling element installation space with respect to the inclined surface and has a larger diameter than the sliding contact portion. outer diameter of the turned portion of the D _a, the diameter of the bottom portion of the groove provided in the base end edge of the side surface of the rolling element installation space side of the inner seal lip and D _B, the inner sealing lip _A wheel bearing rolling bearing unit characterized in that a relationship of D _A ≦ D _B -4 · t is established when a thickness dimension is t . A combination of the seal ring and the inclined surface is provided in an axially outer end opening portion of the rolling element installation space, and the inclined surface is a part of the outer peripheral surface of the hub in the axial direction and the rotation-side flange. The rolling bearing unit for supporting a wheel according to claim 1, which is directly formed in a portion sandwiched between the inner ring raceways on the outer side in the axial direction of the both inner ring raceways . A combination of the seal ring and the inclined surface is provided in an axially outer end opening portion of the rolling element installation space, and the inclined surface is a part of the outer peripheral surface of the hub in the axial direction and the rotation-side flange. said fixedly fitted between part of the axially outer ring raceway of the two inner raceways are formed on the outer peripheral surface of the sliding ring annularly metal, wheel support as claimed in claim 1 Rolling bearing unit for use. A combination of the seal ring and the inclined surface is provided in the axially inner end opening portion of the rolling element installation space, and this inclined surface is fixed to the hub and is made of a metal and annular slinger. provided in a part, the slinger is pre SL and rotating side cylindrical portion which is externally secured to the hub, the rotation-side circular ring which is bent from the axially inner edge of the rotating side cylindrical portion radially outward And an inclined plate portion inclined in the same direction as the inclined surface, which is formed in a part of the rotating cylindrical portion in the axial direction, and the outer peripheral surface of the inclined plate portion is the inclined surface. The rolling bearing unit for wheel support described in any one of -3.

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