JP2017057908A - Bearing unit for wheel support - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing unit for wheel support preventing collapse of roundness of an outer ring raceway surface, and securing performance of a sealing device.SOLUTION: Out of an inner peripheral surface of an outer ring 1a, at a portion between an outer ring raceway surface 4a on an outboard side and an outer ring raceway surface 4b on an inboard side, a plurality of projection parts 14 projecting radially inward with respect to groove shoulder parts 13a, 13b adjacent to outer ring raceway surfaces 4a, 4b is provided over a circumferential direction. To the projection part 14, an annular reinforcement ring 45 is fitted and fixed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wheel support bearing unit that rotatably supports a wheel of an automobile with respect to a suspension device.

As a wheel support bearing unit that rotatably supports a wheel of an automobile, for example, an inner ring rotation type bearing unit as shown in FIG. 4 (Patent Document 1) is known. The wheel support bearing unit rotatably supports, via a plurality of rolling elements 3, a hub wheel 2 that supports and fixes a wheel on an inner diameter side of an outer ring 1 that is fixed to a suspension device of a vehicle body.
In the description of the axial direction in the present specification, the inboard side refers to the side that is the central side in the width direction of the vehicle body with the wheel support bearing unit attached, and is the right side of each figure. On the contrary, the side on the outer side in the width direction of the vehicle body is called the outboard side, which is the left side of each figure.

The outer ring 1 has a double-row outer ring raceway surface 4a, 4b on the inner peripheral surface, a mounting flange 10 for fastening to a knuckle 40 of a suspension device as a vehicle body side member on the outer peripheral surface, and a knuckle 40 on an inboard side end. Each has a knuckle pilot portion 12 fitted to the inner peripheral surface.
The hub wheel 2 has double-row inner ring raceway surfaces 5a and 5b on the outer peripheral surface. Between each outer ring raceway surface 4a, 4b and each inner ring raceway surface 5a, 5b, a plurality of rolling elements 3 are arranged so as to roll freely in each row. In the illustrated example, the rolling element 3 is a ball, but a tapered roller can be used as the rolling element 3.

  When such a wheel support bearing unit is fixed to the knuckle 40, the knuckle pilot portion 12 of the outer ring 1 is inserted from the outboard side to the inner diameter side of the knuckle 40, and the inboard side surface of the mounting flange 10 is out of the knuckle 40. Contact the side of the board. In this state, a plurality of bolts 41 are inserted into the respective bolt holes 11 of the mounting flange 10 and fastened and fixed to the knuckle 40.

In the case of the above-described configuration, the fastening force at the time of fastening the bolt 41 acts on the mounting flange 10, causing deformation of the outer ring 1 after being attached to the knuckle 40.
That is, the fastening force of the bolt 41 (the force that pulls the mounting flange 10 toward the inboard side) acting in the vicinity of the bolt hole 11 of the mounting flange 10 acts in the direction of extending the outboard side portion of the outer ring 1 in the radial direction. The outer ring raceway surface 4a on the outboard side is deformed to have an elliptical shape with a long diameter in the vertical direction. On the other hand, since the fastening force acts in the direction of crushing the inboard side portion of the outer ring 1, the outer ring raceway surface 4b on the inboard side has broken the roundness of an elliptical shape having a long diameter in the horizontal direction. Such collapse of the roundness is noticeable on the outer ring raceway surface 4a on the outboard side that is far from the mounting flange 10 in a bearing having a large degree of uneven distribution in the circumferential position of the bolt hole 11 of the mounting flange 10. It becomes.

  The inner space 8 in which the rolling elements 3 are installed between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the hub wheel 2 is provided with a seal ring 6 on the inner peripheral surface of the outboard end of the outer ring 1 and the outer ring 1. The openings 7 at both ends are sealed by fitting and fixing caps 7 to the inner peripheral surface of the inboard end. Therefore, when the outer ring 1 is deformed by the fastening force of the bolt 41, the fitting force between the seal ring 6 and the cap 7 and the outer ring 1 is reduced, and the cap 7 may drop off or the sealing performance of the seal ring 6 may be reduced. There is. In particular, when a brake is frequently used on a long downhill or the like, the temperature of the wheel support bearing unit rises and the pressure in the internal space 8 increases, and the possibility that the cap 7 is pushed to the inboard side to drop off increases.

  With respect to such a problem, the wheel support bearing unit disclosed in Patent Document 1 (FIG. 4) has an inner diameter dimension between the outer ring raceway surface 4a on the outboard side and the outer ring raceway surface 4b on the inboard side. An annular protrusion 42 smaller than the inner diameter dimension for securing the height of the groove shoulder necessary to prevent the rolling element 3 from climbing onto the groove shoulder is provided (becomes thick and thick), and the cylindrical portion of the outer ring 1 By improving the rigidity, the deformation when attached to the knuckle 40 is prevented.

JP 2014-109324 A JP 2014-024091 A

  However, in the method disclosed in Patent Document 1, since the entire width of the space between the rows of the outer ring raceway surfaces 4a and 4b is thickened (to form a thick wall), the mass increases greatly, and the spring of the suspension device Underweight may increase, which may adversely affect the ride comfort and handling stability of the car. Moreover, the rigidity of the outer ring 1 did not increase for a large increase in mass.

  The present invention has been made in view of such problems of the prior art, and by preventing the deformation of the outer ring raceway surface by increasing the rigidity of the outer ring and preventing deformation of the outer ring raceway surface. An object of the present invention is to provide a wheel support bearing unit that prevents and seals the performance of the sealing device.

  A wheel support bearing unit according to the present invention has an outer ring having a mounting flange fastened to a vehicle body side member on an outer peripheral surface, an outer ring having a double row outer ring raceway surface on an inner peripheral surface, and a double row inner ring raceway on an outer peripheral surface. An inner ring having a surface, and a plurality of rolling elements disposed between each outer ring raceway surface and each inner ring raceway surface, and a sealing device is fitted and fixed to both axial ends of the outer ring. ing.

  In particular, the wheel support bearing unit according to the present invention includes a plurality of rows protruding radially inward from the groove shoulders of the outer ring raceway surface between the outer ring raceway surfaces among the inner peripheral surfaces of the outer ring. Inter-convex portions are provided in the circumferential direction, and an annular reinforcing ring is fitted and fixed to the inter-row convex portions.

  ADVANTAGE OF THE INVENTION According to this invention, while preventing the roundness collapse of an outer ring raceway surface, the bearing unit for wheel support which ensured the performance of the sealing device can be provided.

Sectional drawing of the bearing unit for wheel support which shows 1st Embodiment. Sectional drawing of the bearing unit for wheel support which shows 2nd Embodiment. Sectional drawing of the bearing unit for wheel support which shows 3rd Embodiment. Sectional drawing of the bearing unit for wheel support which shows an example of a prior art.

[First Embodiment]
A first embodiment of the present invention will be described with reference to the drawings. The present embodiment is an embodiment of the present invention, and is not construed as being limited thereto. The design can be changed within the scope of the present invention.
In the present embodiment, an inner ring rotation type wheel support bearing unit for a driven wheel shown in FIG. 1 is assumed, but the technology of the present application is also applicable to a wheel support bearing unit for a drive wheel.

  The wheel support bearing unit of the present embodiment is fixed to a knuckle (not shown) of a suspension device, which is a vehicle body side member, via a bolt, and is rotatably supported by being connected to a wheel on the inner diameter side of the outer ring 1a. A hub wheel 2 to be provided. An annular track formed by a double-row outer ring raceway surface 4a, 4b formed on the inner peripheral surface of the outer ring 1a and a double-row inner ring raceway surface 5a, 5b formed on the outer peripheral surface of the hub wheel 2 is double-rowed. A plurality of rolling elements 3 held by a cage 9 so as to be able to roll are arranged on each track.

  Between the inner peripheral surface of the outer ring 1a and the outer peripheral surface of the hub wheel 2, a rolling element 3 is arranged, and an internal space 8 filled with grease is formed. Attaching the seal ring 6 to the inner peripheral surface of the outer ring 1a on the outboard side and attaching a metal cap 7a to the inner peripheral surface of the outer ring 1a to seal the openings at both ends of the inner space 8 Yes. In the case of a wheel support bearing unit for driving wheels, a combined seal ring can be applied instead of the cap 7a.

  The hub wheel 2 is configured by coupling a hub body 20 and an inner ring member 21. On the outer peripheral surface of the hub body 20, there is a rotating flange 22 projecting radially outward on the outboard side, an inner ring raceway surface 5a on the outboard side in the axial middle portion, and a small diameter step portion 23 on the inboard side. , Each formed. The inner ring member 21 having the inboard-side inner ring raceway surface 5b on the outer peripheral surface is a caulking portion in which the inboard end portion of the hub body 20 is plastically deformed radially outward in a state of being externally fitted to the small-diameter step portion 23. 24 is fixed by caulking. A wheel (not shown) is fixed to the rotating flange 22, and the hub wheel 2 rotates together with the wheel. A cylindrical hub recess 25 that is recessed toward the outboard is formed on the inboard side surface of the hub wheel 2 (hub body 20).

  The outer ring 1a has a substantially cylindrical shape, and a mounting flange 10 fixed to a knuckle (not shown) is provided on the outer peripheral surface near the inboard side so as to protrude radially outward. On the inboard side of the mounting flange 10, a cylindrical knuckle pilot portion 12 fitted to the inner peripheral surface of the knuckle is provided.

  The mounting flange 10 is provided with bolt holes 11 penetrating in the axial direction at a plurality of (for example, three to four) portions protruding radially outward. An inboard-side outer ring raceway surface 4b is formed on the inner diameter side of the outer ring 1a on which the mounting flange 10 is projected so as to overlap the mounting flange 10 in the radial direction. The rigidity is increased by this configuration, and the roundness collapse of the outer ring raceway surface 4b on the inboard side is smaller than that of the outer ring raceway surface 4a on the outboard side.

Of the inner peripheral surface of the outer ring 1a, between the outer ring raceway surface 4a on the outboard side and the outer ring raceway surface 4b on the inboard side (between rows), the groove shoulder portions 13a of the outer ring raceway surfaces 4a and 4b, A plurality of inter-row protrusions 14 are provided in the circumferential direction so as to protrude radially inward from 13b.
Specifically, the inter-row portions of the outer ring raceway surfaces 4a and 4b are formed in a spline shape having a plurality of spline internal teeth (inter-row convex portions 14) extending in the axial direction at equal intervals in the circumferential direction. ing. The diameter dimension of the circumscribed circle at the bottom of each inter-row convex portion 14 is smaller than the groove shoulder portions 13a and 13b adjacent to the outer ring raceway surfaces 4a and 4b. Note that the cross-sectional shape of the inter-row convex portion 14 (inner teeth of the spline) does not have to be a general involute curve, and an angular spline shape is preferable in order to enhance the deformation preventing effect of the outer ring 1a.

Further, a reinforcing ring 45 having an engagement recess 46 (spline external tooth) that engages with the inter-row convex portion 14 is fitted and fixed to a portion between the rows of the outer ring raceways 4a and 4b. The reinforcing ring 45 is formed in an annular shape as a whole by a light metal such as an aluminum alloy, and a plurality of engaging concave portions 46 that engage with the inter-row convex portions 14 are provided in the circumferential direction on the outer peripheral surface thereof. Is provided. By forming the engaging concave portion 46 in a state having a twist angle with respect to the inter-row convex portion 14, it is possible to prevent the looseness and the retaining after the reinforcing ring 45 is fixed to the outer ring 1.
Further, the reinforcing ring 45 has an inner diameter dimension having a gap that does not come into contact with the hub wheel 2 even when a maximum moment load assumed during driving of the automobile is applied to the bearing unit and a relative inclination occurs in the outer and inner rings. Is set to

  The outer ring 1a having the above-described configuration is manufactured by hot forging, and the spline shape formed by the plurality of inter-row convex portions 14 is formed by a cutting process (a partition wall portion existing on the inner diameter of the intermediate material at the time of forming the outer ring). , In the step of punching and removing by press working or the like) (see Patent Document 2). In addition, in the process of cutting the outer ring 1a, it is possible to punch out in a circular shape, and to form the inter-row convex portion 14 (spline shape) by broaching in the subsequent process.

  The knuckle pilot portion 12 of the outer ring 1a has a cylindrical inner peripheral surface, and a cap 7a is fitted and fixed to an end portion of the inboard. The cap 7a is formed by bending the metal plate material into a bottomed cylindrical shape, and includes a cap cylindrical portion 50, a cap flange portion 51, and a cap bottom portion 52. The cap collar portion 51 is formed by bending the inboard end of the cylindrical cap cylindrical portion 51 outward in the radial direction. The cap bottom portion 52 is formed so as to close the outboard side opening of the cap cylindrical portion 50 by bending the outboard end portion of the cap cylindrical portion 50 radially inward.

  In such a cap 7a, the outer peripheral surface of the cap cylindrical portion 50 is fitted into the inner peripheral surface of the knuckle pilot portion 12, and the outboard side surface of the cap collar portion 51 is abutted against the inboard end surface of the knuckle pilot portion 12. Thus, the positioning is fixed to the inboard end portion of the outer ring 1a. The cap bottom portion 52 has substantially the same shape as the inboard side surface of the hub wheel 2, and when attached, the outboard side surface of the cap bottom portion 52 and the entire inboard side surface of the hub wheel 2 are slightly different. Opposing with the gap maintained. Further, a bottomed cylindrical cap bulging portion 53 that bulges toward the outboard side is formed at the center portion of the cap bottom portion 52, and is formed inside the hub recess 25 formed on the inboard side surface of the hub wheel 2. The cap bulging part 53 is made to enter.

  The inner peripheral surface of the outboard end portion of the outer ring 1a has a cylindrical surface shape, and the seal ring 6 is fitted and fixed therein. The seal ring 6 seals the outboard end opening of the outer ring 1 a (inner space 8) by sliding the tip end of a seal lip made of an elastic material over the entire circumference of the hub wheel 2. Yes.

With the above configuration, it is possible to provide a wheel support bearing unit that enhances the rigidity of the outer ring to prevent deformation of the knuckle and prevents the outer ring raceway surface from being broken, and ensures the performance of the sealing device. .
That is, since a plurality of inter-row protrusions 14 projecting radially inward are provided in the inter-row portions of the outer ring raceway surfaces 4a and 4b, the rigidity of the outer ring 1a can be increased for a small increase in mass. . In addition, since the lightweight reinforcing ring 45 is fitted and fixed to the inter-row convex portion 14, the rigidity is further increased while suppressing the increase in the weight of the outer ring 1a, and the outer ring raceway associated with the attachment of the mounting flange 10 to the knuckle. The deformation of the surfaces 4a and 4b can be prevented. Therefore, it is possible to prevent a reduction in the service life of the wheel support bearing unit due to collapse of the roundness of the outer ring raceway surfaces 4a and 4b.

  Further, since the inner peripheral surface on the outboard side of the outer ring 1a to which the seal ring 6 is fitted is not deformed, foreign matter can be prevented from entering through the gap generated on the fitting surface, and the sealing performance of the seal ring 6 can be maintained. . Similarly, since the inner peripheral surface of the knuckle pilot portion 12 is not deformed, the fitting force can be maintained and the cap 7a can be prevented from falling off. Further, the inter-row convex portion 14 and the reinforcing ring 45 occupy the space between the rows of the outer ring raceways 4a and 4b, and the cap bottom portion 52 faces the entire surface of the inboard side surface of the hub wheel 2 with a slight gap. Therefore, the amount of air existing in the internal space 8 is greatly reduced. Therefore, even when the temperature of the bearing unit rises, the pressure rise accompanying the expansion of the air in the internal space 8 is alleviated and the cap 7a is prevented from falling off.

Although a light metal is exemplified as the material of the reinforcing ring 45, various materials can be selected depending on the thickness (rigidity) of the outer ring 1a and the degree of uneven distribution of the bolt holes 11.
For example, when the outer ring is relatively thick and the bolt holes are relatively evenly distributed, the reinforcing ring 45 can be manufactured from a lightweight resin material. Accordingly, it is possible to prevent the outer ring raceway surface from collapsing while keeping the increase in mass to a minimum, and to ensure the performance of the sealing device. On the other hand, when the outer ring is relatively thin and the bolt holes are unevenly distributed, the reinforcing ring 45 can be manufactured from a material having high rigidity such as carbon steel. Thereby, the performance of the sealing device can be ensured while preventing the roundness of the outer ring raceway surface from collapsing.

  Although the spline shape is illustrated as the shape of the inter-row convex portion 14 and the engagement concave portion 46, the cross-sectional shape of the inter-row portion can be an ellipse, a petal shape, a polygon, or the like. In these cases, the cross-sectional shape of the inter-row convex portion 14 is a crescent shape, a triangular shape, a partial circular shape, or the like. Further, by applying an adhesive, welding, or the like to the engaging portion between the inter-row convex portion 14 and the engaging concave portion 46, it is possible to prevent the reinforcing ring 45 from moving in the axial direction.

[Second Embodiment]
FIG. 2 shows a second embodiment of the present invention. In the case of the wheel support bearing unit of the present embodiment, a flange 47 protruding radially outward is formed on one side of the reinforcing ring 45a in the axial direction, and the flange 47 is formed as a groove shoulder between the inter-row protrusion 14 and the outer ring 1b. By holding between the retaining ring 48 locked to the portion 13b, the reinforcing ring 45a is prevented from moving in the axial direction.

When the reinforcing ring 45a is manufactured from a resin material, there is a possibility that the fastening allowance of the engaging recess 46 may be lost due to rheological resin flow with long-term use. Further, when the reinforcing ring 45a is manufactured from a light metal, there is a possibility that the fastening allowance of the engaging recess 46 may be lost due to fretting wear of the engaging recess 46. In the present embodiment, even if the tightening allowance of the engaging recess 46 is lost, the reinforcing ring 45a is prevented from moving in the axial direction and interfering with the rolling elements 3 and the cage 9. In the illustrated example, the flange 47 is provided on the inboard side, and the retaining ring 48 is locked to the groove shoulder 13b on the inboard side. However, the flange 47 is formed on the outboard side, It can also be set as the structure which latches the retaining ring 48 to the part 13a.
Other configurations and operational effects are the same as those of the first embodiment described above.

[Third Embodiment]
FIG. 3 shows a third embodiment of the present invention. In the case of the wheel support bearing unit of the present embodiment, by retaining the retaining ring 48 on the groove shoulders 13a and 13b of the outer ring 1c and sandwiching the reinforcing ring 45b between the two retaining rings 48, The reinforcing ring 45b is prevented from moving in the axial direction.
Other configurations and operational effects are the same as those of the first embodiment described above.

  The wheel support bearing unit of the present invention can be suitably used as a bearing unit that rotatably supports a wheel of an automobile.

1, 1a, 1b, 1c Outer ring 2 Hub wheel 3 Rolling elements 4a, 4b Outer ring raceway surface 5a, 5b Inner ring raceway surface 6 Seal ring 7, 7a Cap 8 Retainer 9 Inner space 10 Mounting flange 11 Bolt hole 12 Knuckle pilot part 13a , 13b Groove shoulder portion 14 Inter-row convex portion 20 Hub body 21 Inner ring member 22 Rotating flange 23 Small diameter step portion 24 Caulking portion 25 Hub concave portion 40 Knuckle 41 Bolt 42 Annular protrusion 45, 45a, 45b Reinforcement ring 46 Engaging concave portion 47 Part 48 retaining ring 50 cap cylindrical part 51 cap collar part 52 cap bottom part 53 cap bulging part

Claims (1)

An outer ring having a mounting flange fastened to the vehicle body side member on the outer peripheral surface, and having a double-row outer ring raceway surface on the inner peripheral surface;
An inner ring having a double-row inner ring raceway surface on the outer circumferential surface;
A plurality of rolling elements arranged between each outer ring raceway surface and each inner ring raceway surface,
A wheel support bearing unit in which a sealing device is fitted and fixed to both axial ends of the outer ring,
Among the inner peripheral surfaces of the outer ring, between the outer ring raceway surfaces, a plurality of inter-row convex portions protruding radially inward from the groove shoulders of the outer ring raceway surface are provided over the circumferential direction. A wheel support bearing unit, wherein an annular reinforcing ring is fitted and fixed to the inter-row convex portion.

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