JP2009190655A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To fit a retaining ring to the retaining ring groove of a housing with a relatively small pressing pressure without damaging the housing and the retaining ring by improving a form of the retaining ring, in a bearing device for a wheel wherein a roller bearing fit to an inner circumference of the housing is prevented from coming off by the retaining ring. <P>SOLUTION: The bearing device 1 for the wheel is provided with the roller bearings 2 and the annular housing 7 in which outer rings 4 of the roller bearing fit with an inner circumference. The outer ring 4 is prevented from coming off as an end surface abuts on a level difference part 11b of the housing 7 and another end surface abuts on the retaining ring 14. The retaining ring 14 is elastically expandable and contractable in the radial direction, contractedly inserted in the inner circumference of the housing 7, and expands with an elastic restoration force being pressed to a position of the retaining ring groove 14. A cross section form of the end surface 14b of the one end side of the retaining ring 14 is a convex surface with at least its outer diameter part closer to the other end side as it is closer to an outer diameter side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wheel bearing device used as an axle unit for large vehicles such as trucks and buses.

  As an axle unit for a large vehicle, for example, a structure disclosed in Patent Document 1 is known. As shown in FIG. 7, the axle unit includes a unitized double row rolling bearing 2 and an annular housing 7 in which an outer ring 4 of the rolling bearing 2 is fitted to the inner periphery. Further, a hub 32 and a brake rotor 33 for attaching a wheel to a wheel are attached by bolts 31. The wheel is attached to the hub 32.

In this type of axle unit, the outer ring 4 of the rolling bearing 2 is usually fitted into the inner periphery of the housing 7 by press fitting. In that case, when the axle unit is subjected to a high load, a retaining ring 14 for restricting the axial movement of the outer ring 4 is attached to the housing 7 in order to prevent the outer ring 4 from creeping and coming off in the axial direction. It is done. In the example of FIG. 7, the outer ring 4 is prevented from coming off by bringing one end surface of the outer ring 4 into contact with the stepped surface 11 b of the housing 7 and bringing the other end surface into contact with the retaining ring 14. The retaining ring 14 is fitted in an annular retaining ring groove 13 formed on the inner periphery of the housing 7.
Japanese Patent Laid-Open No. 2003-312205

  The retaining ring 14 is, for example, an annular shape in which one place in the circumferential direction is divided, and has elasticity that can expand and contract in the radial direction. Using this elasticity, the retaining ring 14 in a contracted state is inserted into the inner periphery of the housing 7, and the retaining ring 14 is pushed into the retaining ring groove 13 side along the inner periphery of the housing 7. Fit into the groove 13. In a state where the retaining ring 14 is fitted in the retaining ring groove 13, the retaining ring 14 is maintained in an expanded state due to elasticity, and thus does not come off from the retaining ring groove 13.

  When the retaining ring 14 is fitted into the retaining ring groove 13 by the above method, when the retaining ring 14 is pushed, the outer periphery of the retaining ring 14 is easily caught on the inner circumference of the housing 7, and a large force is required to push the retaining ring 14. Further, if the retaining ring 14 is forcibly pushed in, the housing 7 and the retaining ring 14 may be damaged.

  An object of the present invention is to provide a wheel bearing device in which a rolling bearing fitted to the inner periphery of a housing is prevented from coming off by a retaining ring, and by devising the shape of the retaining ring, the housing and the retaining member can be obtained with a relatively small pushing force. It is to be able to fit the retaining ring into the retaining ring groove of the housing without damaging the ring.

A wheel bearing device according to the present invention includes a rolling bearing and an annular wheel mounting housing in which an outer ring of the rolling bearing is fitted to an inner periphery, and the housing projects toward an inner diameter side at one end side of the inner periphery. The retaining ring has an annular retaining ring groove on the other end side, and a retaining ring elastically expandable and contractable in the radial direction is fitted in the retaining ring groove in an expanded state. A wheel bearing device in which one end surface is in contact with the stepped portion and the other end surface is in contact with the retaining ring, and the retaining ring is contracted from the other end side to the inner periphery of the housing. Inserted in a state, pushed to the position of the retaining ring groove and expanded by elastic restoring force, and at least the outer diameter portion of the retaining ring has a cross-sectional shape toward the outer diameter side. The convex surface is located on the other end side.
According to this configuration, since the cross-sectional shape of the end surface on one end side of the retaining ring is a convex curved surface that is located on the other end side as the outer diameter portion moves toward the outer diameter side, the retaining ring is formed into the retaining ring groove. When fitting, the outer periphery of the retaining ring is not caught on the inner periphery of the housing. Therefore, the retaining ring can be pushed in with a relatively small pushing force, and the housing and the retaining ring are not damaged.

In this invention, the cross-sectional shape of the end surface on the one end side of the retaining ring may be a convex curved surface that is positioned on the other end side from the intermediate portion of the radial width toward the outer diameter side and the inner diameter side. The range from the intermediate portion of the radial width to the outer diameter end is a convex curved surface positioned on the other end side as it goes to the outer diameter side, and the range from the intermediate portion of the radial width to the inner diameter end is the axial direction. It may be a flat surface.
For the cross-sectional shape from the intermediate part of the radial width on the end face to the inner diameter end, it may be a convex curved surface located on the other end side as it goes to the inner diameter side, or a plane facing the axial direction, In the latter case, since the rolling bearing is received on the plane, the axial movement of the rolling bearing can be minimized.

In the present invention, the housing can be made of spheroidal graphite cast iron.
Spheroidal graphite cast iron is excellent in tensile strength, elongation, and tenacity (toughness), and is widely used in automobile parts. Spheroidal graphite cast iron can also be suitably used in the configuration of the present invention.
The housing may be made of low and medium carbon steel.

It can be set as the structure which has the flange for wheel attachment in the outer periphery of the said housing.
The present invention can be applied to either a configuration having a wheel mounting flange on the outer periphery of the housing or a configuration having no flange.

  The wheel bearing device of the present invention includes a rolling bearing and an annular wheel mounting housing in which an outer ring of the rolling bearing is fitted to the inner periphery, and the housing protrudes toward the inner diameter side at one end side of the inner periphery. There is a stepped portion and an annular retaining ring groove on the other end side. In this retaining ring groove, a retaining ring that is elastically expandable / contractable in the radial direction is fitted in an expanded state. A bearing device for a wheel that has an end surface that abuts against the stepped portion and a second end surface that abuts against the retaining ring and is prevented from coming off, and the retaining ring is contracted from the other end side to the inner periphery of the housing. Inserted into the retaining ring groove and expanded by elastic restoring force, and the cross-sectional shape of the end surface on the one end side of this retaining ring is such that at least the outer diameter portion goes to the outer diameter side. Due to the convex curved surface located on the other end side, relatively small push-in In, without damaging the housing and retaining ring can be fitted a retaining ring to the retaining ring groove of the housing.

  An embodiment of the present invention will be described with reference to FIG. The wheel bearing device 1 of this embodiment is an outer ring rotating type and is applied to a driven wheel axle unit such as a truck or a bus. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side.

  The wheel bearing device 1 includes a rolling bearing 2 and a housing 7 fitted to the outer periphery of the rolling bearing 2. The rolling bearing 2 includes a pair of inner rings 3 having raceway surfaces 3a on the outer peripheral surface, an outer ring 4 having double-row raceway surfaces 4a facing the raceway surfaces 3a of the pair of inner rings 3, and inner and outer rings. The rolling element 5 of the double row | line | column integrated between 3 and 4 is provided. In the case of this embodiment, the rolling element 5 is a tapered roller, and is configured as a tapered roller bearing. The double row tapered rollers which are the rolling elements 5 are arranged in a combination of the back and are held by the cage 6 for each row. Both ends of the bearing space between the inner ring 3 and the outer ring 4 are sealed by seals 8 and 9, respectively.

  The housing 7 is an annular member, and an inner peripheral surface 11 thereof is a press-fit surface portion 11a into which the outer ring 4 is press-fitted, and the press-fitting surface portion 11a is connected to the outboard side via a step surface 11b than the press-fit surface portion 11a. It is formed in the shape of a stepped cylindrical surface comprising a small-diameter inner protrusion 11c. Wheel mounting bolt holes 12 are provided at a plurality of locations in the circumferential direction on the end surface of the housing 7 on the outboard side.

  The housing 7 can be manufactured by casting. As the material of the housing 7, spheroidal graphite cast iron, low, medium carbon steel, or other cast iron can be used. Low and medium carbon steel is low carbon steel or medium carbon steel. Spheroidal graphite cast iron is excellent in tensile strength, elongation, and tenacity (toughness). When using spheroidal graphite cast iron, the hardness is preferably HB130-330. When low and medium carbon steel is used, the hardness is preferably HRC 13-30. Moreover, when using any material, it is preferable that material fatigue strength is 200 Mpa or more.

  The rolling bearing 2 is incorporated into the housing 7 by press-fitting the outer ring 4 into the inner peripheral surface press-fitting surface portion 11 a of the housing 7 from the inboard side. After the assembly, the retaining ring 14 is fitted into the annular retaining ring groove 13 formed on the inner periphery of the housing 7. In the state in which the rolling bearing 2 is assembled in the housing 7, the outer ring 4 has its end face on the outboard side in contact with the inner peripheral surface step portion 11 b of the housing 7, and movement to the outboard side is restricted. The board-side end face abuts against the retaining ring 14 and is prevented from coming off.

  The retaining ring 14 is, for example, an annular shape in which one place in the circumferential direction is divided, and has elasticity that can expand and contract in the radial direction. The cross-sectional shape of the retaining ring 14 is such that the end surface 14a on the inboard side is a flat surface, and the end surface 14b on the outboard side faces the inboard side toward the outer diameter side and the inner diameter side in the axial direction at the middle part of the radial width. The outer diameter end and the inner diameter end are curved with no inflection points along the axial direction, for example, arcs. In other words, the end surface 14b on the outboard side is a convex curved surface that is positioned at the other end side as the outer diameter portion moves toward the outer diameter side. There is no surface corresponding to the outer peripheral surface and the inner peripheral surface, and the end surface 14b on the outboard side and the end surface 14a on the inboard side are directly connected to each other at the outer diameter end and the inner diameter end. It is preferable to chamfer the connecting portion between the end surface 14b on the outboard side and the end surface 14a on the inboard side.

  A method for fitting the retaining ring 14 will be described with reference to FIG. A guide jig 15 and a pressing jig 16 are used for fitting the retaining ring 14. The guide jig 15 is an annular jig, the one end surface 15a has a stepped portion 15aa that can be fitted to the outer periphery of the end portion on the inboard side of the housing 7, and the inner peripheral surface 15b is an inner surface of the end surface 15a. A cylindrical surface portion 15ba having the same diameter as the inner diameter of the housing 7 is provided following the periphery, and a tapered surface portion 15bb having a larger diameter as the distance from the end surface 15a continues from the cylindrical surface portion 15ba. The pressing jig 16 is a cylindrical jig and has an outer diameter smaller than the inner diameter of the housing 7 and larger than the inner diameter of the retaining ring 14 in the expanded state.

  The guide jig 15 is provided by fitting the stepped portion 15aa to the end portion on the inboard side of the housing 7, and an extended retaining ring 14 is disposed on the inner periphery of the guide jig 15 (FIG. 2A). )). When the retaining ring 14 is pushed to the outboard side by the pressing jig 16, the retaining ring 14 moves from the tapered surface portion 15bb of the inner periphery of the guide jig 15 to the cylindrical surface portion 15ba, and accordingly, from the expanded state to the contracted state. The diameter is reduced (FIG. 2B). Since the end face on the outboard side of the retaining ring 14 has the cross-sectional shape, the outer periphery of the retaining ring 14 is not caught on the inner periphery of the housing 7 during movement. Therefore, the retaining ring 14 can be pushed with a relatively small pushing force, and the housing 7 and the retaining ring 14 are not damaged.

  When the retaining ring 14 is continuously pushed, the retaining ring 14 is pushed into the inner periphery of the housing 7 in a contracted state (FIG. 2C). Further, when the retaining ring 14 is pushed and the retaining ring 14 reaches the position of the retaining ring groove 13, the retaining ring 14 expands by its own elasticity and fits into the retaining ring groove 13 (FIG. 2 (D)). Since the retaining ring 14 is maintained in an expanded state by elasticity, the retaining ring 14 does not come off from the retaining ring groove 13.

  The retaining ring 14 may have a cross-sectional shape shown in FIG. That is, the retaining ring 14 has a cross-sectional shape of the end surface 14b on the outboard side, that is, a curved portion 14ba from the intermediate portion of the radial width to the outer diameter end, and a flat portion 14bb from the intermediate portion of the radial width to the inner diameter end. And become. The curved portion 14ba faces the axial direction at the intermediate portion of the radial width, is located on the inboard side as it goes from the intermediate portion of the radial width to the outer diameter side, and there is no inflection point along the axial direction at the outer diameter end. A curved line, for example, an arc. The plane portion 14bb is a plane that faces the axial direction. The outer diameter end of the end surface 14b on the outboard side and the outer diameter end of the end surface 14a on the inboard side are directly connected, and between the inner diameter end of the end surface 14b on the outboard side and the inner diameter end of the end surface 14a on the inboard side, A cylindrical inner peripheral surface 14c is formed.

  When the retaining ring 14 has a cross-sectional shape, when the retaining ring 14 is fitted into the retaining ring groove 13, the outer periphery of the retaining ring 14 is not caught on the inner periphery of the housing 7, and the retaining ring 14 is moved with a relatively small pushing force. In addition to the effect that the housing 7 and the retaining ring 14 are not damaged, the outer ring 4 of the rolling bearing 1 is received by the flat portion 14ba of the end surface 14b on the outboard side. The effect of minimizing movement is obtained.

  The retaining ring 14 in FIGS. 1 and 3 has no surface corresponding to the outer peripheral surface, and the end surface 14b on the outboard side and the end surface 14a on the inboard side are directly connected to each other at the outer diameter ends. As in the retaining ring 14 shown in FIG. 5, a cylindrical outer peripheral surface 14d may be provided between the outer diameter ends of the end surface 14b on the outboard side and the end surface 14a on the inboard side. Also in this case, when the retaining ring 14 is fitted into the retaining ring groove 13, the outer periphery of the retaining ring 14 can be prevented from being caught on the inner periphery of the housing 7.

  FIG. 6 shows a different embodiment. The wheel bearing device 1 of this embodiment is an outer ring rotating type, and is applied to an axle unit for driving wheels such as a truck and a bus. This embodiment is different from the above embodiment in that a flange 21 for attaching a wheel to a wheel is provided on the outer periphery of the housing 7. The flange 21 is provided with bolt insertion holes 22 at a plurality of locations in the circumferential direction. Bolt holes 23 provided on the end face of the housing 7 on the outboard side are for axle connection.

  Similarly to the above, the wheel bearing device 1 of this embodiment also press-fits the outer ring 4 of the rolling bearing 2 into the inner peripheral surface press-fitting surface portion 11a of the housing 7 from the inboard side, and incorporates the rolling bearing 2 into the housing 7, A retaining ring 14 is fitted into the retaining ring groove 13 to prevent the outer ring 4 from coming off. As the retaining ring 14, the same thing as the said embodiment is used, and the same effect is obtained. 6 shows the retaining ring 14 shown in FIG. 1, but any retaining ring 14 shown in FIGS. 3 to 5 may be used.

  In the above embodiments, the rolling bearing 2 is a tapered roller bearing type, but may be a ball bearing type such as an angular ball bearing.

(A) is sectional drawing of the wheel bearing apparatus concerning embodiment of this invention, (B) is the IB section enlarged view which abbreviate | omitted the part. It is explanatory drawing of the fitting procedure of a retaining ring. It is a fragmentary sectional view of the wheel bearing apparatus using a different retaining ring. Furthermore, it is a fragmentary sectional view of a different retaining ring. Furthermore, it is a fragmentary sectional view of a different retaining ring. (A) is sectional drawing of the bearing apparatus for wheels concerning different embodiment of this invention, (B) is the VIB part enlarged view which abbreviate | omitted the part. It is sectional drawing of the conventional axle unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wheel bearing apparatus 2 ... Rolling bearing 3 ... Inner ring 4 ... Outer ring 7 ... Housing 13 ... Retaining ring groove 14 ... Retaining ring 14b ... Outboard side end surface 14ba ... Curved surface part 14bb ... Planar part 21 ... Flange

Claims (6)

A rolling bearing, and an annular wheel mounting housing in which an outer ring of the rolling bearing is fitted to the inner circumference, the housing having a stepped portion projecting toward the inner diameter side at one end side of the inner circumference, and the other end An annular retaining ring groove is provided on the side, and a retaining ring that is elastically expandable and contractable in the radial direction is fitted in an expanded state in the retaining ring groove, and one end surface of the outer ring abuts on the stepped portion, A wheel bearing device in which the other end surface is prevented from coming off by contacting the retaining ring,
The retaining ring is inserted from the other end side into the inner periphery of the housing in a contracted state, is pushed to the position of the retaining ring groove, and is expanded by an elastic restoring force. The wheel bearing device is characterized in that the cross-sectional shape of the end surface is a convex curved surface that is positioned at the other end side as the outer diameter portion moves toward the outer diameter side.   2. The wheel bearing device according to claim 1, wherein the cross-sectional shape of the end face on the one end side of the retaining ring is a convex curved surface that is positioned on the other end side from the intermediate portion of the radial width toward the outer diameter side and the inner diameter side. .   The cross-sectional shape of the end surface on the one end side of the retaining ring according to claim 1 is a convex curved surface that is positioned on the other end side as the range from the intermediate portion of the radial width to the outer diameter end is increased toward the outer diameter side. A wheel bearing device in which the range from the intermediate portion of the radial width to the inner diameter end is a flat surface facing the axial direction.   The wheel bearing device according to any one of claims 1 to 3, wherein the housing is made of spheroidal graphite cast iron.   The wheel bearing device according to any one of claims 1 to 3, wherein the housing is made of low and medium carbon steel.   6. The wheel bearing device according to claim 1, wherein a wheel mounting flange is provided on an outer periphery of the housing.

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