JP2008019899A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel which can reduce hoop stress applied to the raceway surface of an inner ring without increasing thickness in a radial and width directions of an inner wheel. <P>SOLUTION: The bearing device for a wheel is equipped with double rows of rolling elements 5 interposed between respective raceway surfaces 3, 4 of an outer member 1 and inner member 2. The inner member 2 comprises a hub wheel 9 having a flange 9a and an inner ring 10 press-fitted to the outer periphery of an in-board side end of a shaft part 9b in the hub wheel 9. An inner-diameter surface of the inner ring 10 is provided with an annular recess 12 in an axial range W including the raceway surface 4 of the inner ring 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wheel bearing device for an automobile or the like, and more particularly to a wheel bearing device of a type in which an inner ring is press-fitted into an inboard side end of a shaft portion of a hub wheel.

In the wheel bearing device in which the inner ring is press-fitted into the hub ring, hoop stress, that is, stress that is pulled in the circumferential direction is applied to the raceway surface and the outer diameter portion of the inner ring. In particular, in a type in which a caulking portion is provided at the end of the inboard side of the hub wheel and the inner ring is tightened in the axial direction with respect to the hub wheel (for example, Patent Document 1), the outer diameter surface of the hub ring is increased. Because of the diameter, the hoop stress applied to the raceway surface and the outer diameter portion of the inner ring further increases. Thus, when the hoop stress on the raceway surface of the inner ring is increased, the life of the bearing is reduced.
Therefore, in the caulking type wheel bearing device, the hoop stress is reduced by increasing the thickness of the inner ring in the radial direction and the width direction.
JP-A-11-129703

  However, in a caulking type wheel bearing device, when the inner ring is thickened in the radial direction or width direction, a design that increases the shaft diameter of the hub ring is required to maintain the strength of the hub ring. Therefore, it becomes an impediment to reducing the cost by reducing the material.

  An object of the present invention is to provide a wheel bearing device that can reduce hoop stress applied to a raceway surface of an inner ring without increasing the thickness in the radial direction and width direction of the inner ring.

A wheel bearing device according to a first aspect of the present invention has an outer member having a double-row raceway surface on the inner periphery and attached to the vehicle body, and a double-row raceway surface facing the raceway surface on the outer periphery. An inner member having a wheel mounting flange on the outer periphery of the outboard side end, and a double row of rolling elements interposed between the outer member and the raceway surface of the inner member, the inner member, In a wheel bearing device including a hub ring having the flange and an inner ring press-fitted to an outer periphery of an inboard side end of a shaft portion of the hub ring, a shaft provided with a raceway surface of the inner ring on an inner diameter surface of the inner ring An annular recess is provided in the direction range.
According to this configuration, since the annular recess is provided on the inner diameter surface of the inner ring in the axial range in which the raceway surface of the inner ring is provided, even if the inner ring is press-fitted into the hub ring, the diameter expansion force accompanying the press-fitting is not increased. Acting on the portion of the raceway surface on the outer diameter surface is mitigated, and an increase in hoop stress on the raceway surface of the inner ring is suppressed. Therefore, it is possible to suppress an increase in hoop stress generated on the inner ring raceway surface due to the press-fitting of the inner ring into the hub ring shaft portion without increasing the thickness of the inner ring in the radial direction or the width direction.

A wheel bearing device according to a second aspect of the present invention has an outer member having a double-row raceway surface on the inner periphery and attached to the vehicle body, and a double-row raceway surface facing the raceway surface on the outer periphery. An inner member having a wheel mounting flange on the outer periphery of the outboard side end, and a double row of rolling elements interposed between the outer member and the raceway surface of the inner member, the inner member, In a wheel mounting bearing device including a hub ring having the flange and an inner ring press-fitted into an outer periphery of an inboard side end of a shaft portion of the hub ring, a raceway surface of the inner ring is provided on an inner ring fitting surface of the hub ring. An annular recess is provided in the specified axial range.
According to this configuration, since the annular recess is provided in the axial range in which the inner ring raceway surface is provided on the inner ring fitting surface of the hub ring, in this case, even if the inner ring is press-fitted into the hub ring, The accompanying expansion force is mitigated from acting on the raceway surface portion of the inner ring outer diameter surface, and an increase in hoop stress on the raceway surface of the inner ring is suppressed. Therefore, it is possible to suppress an increase in hoop stress generated on the inner ring raceway surface due to the press-fitting of the inner ring into the hub ring shaft portion without increasing the thickness of the inner ring in the radial direction or the width direction.

In these inventions, the inner member may be one in which the inner ring is tightened in the axial direction with respect to the hub ring by a crimping portion provided on the outer periphery of the inboard side end of the hub ring.
In the case of the structure in which the above-described crimping portion is provided on the hub ring, the hoop stress applied to the raceway surface and the outer diameter portion of the inner ring is further increased due to the expansion of the outer diameter surface of the hub wheel due to the crimping. If the inner ring surface of the inner ring or the outer diameter surface of the hub ring is provided with an annular recess in the axial direction where the inner ring raceway surface is provided, the hoop stress associated with caulking is also reduced, and the inner ring raceway surface The hoop stress can be kept low.

  In these first and second inventions, the depth of the recess is preferably 0.1 to 1 mm. If the depth of the dent is less than 0.1 mm, the effect of reducing the hoop stress on the inner ring raceway surface due to the provision of the dent will not be sufficiently obtained, and if it is deeper than 1 mm, the strength of the inner ring or hub ring will be reduced. Unfavorable above.

In these first and second inventions, the wheel bearing device is an angular ball bearing type, and the axial position of the indented portion is a position that is applied to the axial position of the contact point with the rolling element of the inner ring raceway surface. There may be.
In the case of the angular ball bearing type, the rolling element locally contacts the inner ring raceway surface at the contact point, and the hoop stress at this contact point has a great influence on the bearing life. In order to reduce the hoop stress of the outer diameter surface of the inner ring at the axial position where the recess is provided, the recess has the same position as the contact point of the inner ring raceway surface with the rolling element. By doing so, it is possible to obtain a reduction in hoop stress at the contact point that has the greatest influence on the life.

A wheel bearing device according to a first aspect of the present invention has an outer member having a double-row raceway surface on the inner periphery and attached to the vehicle body, and a double-row raceway surface facing the raceway surface on the outer periphery. An inner member having a wheel mounting flange on the outer periphery of the outboard side end, and a double row of rolling elements interposed between the outer member and the raceway surface of the inner member, the inner member, In a wheel bearing device including a hub ring having the flange and an inner ring press-fitted to an outer periphery of an inboard side end of a shaft portion of the hub ring, a shaft provided with a raceway surface of the inner ring on an inner diameter surface of the inner ring Since the annular recess is provided in the direction range, the hoop stress acting on the inner ring raceway surface can be reduced without increasing the thickness in the radial direction or width direction of the inner ring.
A wheel bearing device according to a second aspect of the present invention has an outer member having a double-row raceway surface on the inner periphery and attached to the vehicle body, and a double-row raceway surface facing the raceway surface on the outer periphery. An inner member having a wheel mounting flange on the outer periphery of the outboard side end, and a double row of rolling elements interposed between the outer member and the raceway surface of the inner member, the inner member, In a wheel mounting bearing device including a hub ring having the flange and an inner ring press-fitted into an outer periphery of an inboard side end of a shaft portion of the hub ring, a raceway surface of the inner ring is provided on an inner ring fitting surface of the hub ring. Since the annular recess is provided in the axial range, the hoop stress acting on the inner ring raceway surface can be reduced without increasing the thickness in the radial direction or width direction of the inner ring.

An embodiment of the present invention will be described with reference to FIGS. This embodiment is a third generation inner ring rotating type and is applied to a wheel bearing device for supporting a driven wheel. 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 includes an outer member 1 having double-row raceway surfaces 3 on the inner periphery, an inner member 2 having double-row raceway surfaces 4 facing the raceway surfaces 3 on the outer periphery, A rolling element 5 having double rows interposed between the raceway surfaces 3 and 4 of the side member 1 and the inner member 2 is provided, and the wheel is rotatably supported with respect to the vehicle body. This wheel bearing device is of an angular ball bearing type in which the bearing contact angle θ of the double-row raceway surfaces 3 and 4 face each other, and the rolling elements 5 are formed of balls, and each row is held by a cage 6. Is retained. The bearing spaces between the outer member 1 and the inner member 2 are sealed by seals 7 and 8, respectively.

  The outer member 1 is an integral part as a whole on the fixed side, and is attached to a vehicle suspension (not shown) via a flange (not shown) on the outer periphery.

  The inner member 2 is a member on the rotation side, and includes a hub wheel 9 having a wheel mounting flange 9a on the outer periphery of the outboard side end, and an inboard side end of the shaft portion 9b of the hub ring 9. The inner ring 10 is fitted into the outer periphery in a press-fit state. The hub ring 9 and the inner ring 10 are formed with the raceway surfaces 4 in each row. A pilot portion 9c for guiding a wheel and a brake rotor (both not shown) protrudes from the side surface on the outboard side at the base end of the flange 9a of the hub wheel 9. Bolt holes 11 are provided at a plurality of locations in the circumferential direction of the flange 9a, and wheel fastening bolts (not shown) are attached. At the inboard side end of the shaft portion 9b of the hub wheel 9, a caulking portion 9d that protrudes to the outer periphery and presses the width surface of the inner ring 10 in the axial direction is provided. The portion of the shaft portion 9b of the hub wheel 9 where the inner ring 10 is fitted has a smaller diameter than the other portions, and a step surface 9e facing in the axial direction is provided at the end portion on the inboard side. The inner ring 10 fitted to the shaft portion 9b of the hub wheel 9 is fastened and fixed in the axial direction by the step surface 9e and the caulking portion 9d.

  FIG. 2 shows an enlarged view of part A in FIG. As shown in the figure, an annular recess 12 is provided on the inner diameter surface of the inner ring 10. The recessed portion 12 is set over substantially the entire range of the axial range W in which the raceway surface 4 of the inner ring 10 is provided. The dent 12 has an arcuate cross-sectional shape in which the center in the width direction is deepest. The depth of the recess 12 is preferably 0.1 to 1 mm.

  According to the wheel bearing device having this configuration, the inner ring 10 is connected to the hub ring because the inner ring 10 is provided with the annular recess 12 in the axial range W in which the raceway surface 4 of the inner ring 10 is provided. Even if it press-fits to 9, it will relieve | moderate that the diameter expansion force accompanying press fit acts on the part of the track surface 4 in an inner ring | wheel outer diameter surface, and the increase in the hoop stress of the track surface 4 of the inner ring | wheel 10 will be suppressed. Further, the increase in the hoop stress of the inner ring raceway surface 4 due to the caulking process of the caulking portion 9d is alleviated by the formation of the recessed portion 12. Therefore, it is possible to suppress an increase in hoop stress generated in the inner ring raceway surface 4 due to the press-fitting of the inner ring 10 into the hub ring shaft portion 9b without increasing the thickness of the inner ring 10 in the radial direction or the width direction.

In the example of FIG. 2, the recess 12 of the inner ring 10 is provided over the entire range of the axial range W in which the raceway surface 4 of the inner ring 10 is provided, but a part of the axial range W as shown in FIG. May be provided locally. In this case, on the inner diameter surface of the inner ring 10, an annular recess 12 </ b> A is provided at a position on the axial position of the contact point P of the raceway surface 4 of the inner ring 10 with the rolling element 5. The contact point P is a position where a straight line L that forms a bearing contact angle θ of the inner ring raceway surface 4 intersects the inner ring raceway surface 4.
In the case of the angular ball bearing type, the rolling element 5 is locally in contact with the inner ring raceway surface 4 at the contact point P. Therefore, the hoop stress at the contact point P has a great influence on the bearing life. The recessed portion 12A reduces the hoop stress on the outer diameter surface of the inner ring at the axial position where the recessed portion 12A is provided most greatly. Therefore, by setting the axial position of the recess 12 as the contact point P with the rolling element 5 of the inner ring raceway surface 4, the hoop stress can be reduced at the contact point P having the greatest influence on the life. For this reason, even when the recessed portion 12A is locally provided in a very small part of the raceway surface width, the hoop stress of the inner raceway surface 4 can be reduced by setting the recessed portion 12A to the axial position applied to the contact point P.

  4 to 6 show another embodiment of the present invention. In the wheel bearing device, in the embodiment shown in FIGS. 1 to 3, the inner ring 10 is fitted to the shaft portion 9 b of the hub ring 9 instead of providing the recess 12 (12 </ b> A) on the inner diameter surface of the inner ring 10. An annular recess 13 is provided on the surface. In FIG. 5 showing the B portion of FIG. 4 in an enlarged manner, an annular recess 13 is set over the entire axial range W where the raceway surface 4 of the inner ring 10 is provided. Also in this case, the depth of the recess 13 is preferably 0.1 to 1 mm.

  Even in the case where the recess 13 is provided on the fitting surface of the inner ring 10 in the shaft portion 9b of the hub wheel 9 as in this configuration, the stress that causes the inner ring 10 to increase in diameter by press-fitting the inner ring 10 and the inner ring 10 during caulking are reduced. The stress for expanding the diameter is reduced, and the hoop stress of the inner ring raceway surface 4 can be reduced. Therefore, also in this case, an increase in the hoop stress of the inner ring raceway surface 4 due to the inner ring 10 being press-fitted can be suppressed without increasing the thickness of the inner ring 10 in the radial direction or the width direction.

In FIG. 5, the recessed portion 13 of the hub wheel shaft portion 9b is provided over the entire range of the axial range W in which the raceway surface 4 of the inner ring 10 is provided, but a part of the axial range W as shown in FIG. May be provided. That is, in the configuration example of FIG. 6, in the inner ring fitting surface of the hub ring shaft portion 9 b, a locally annular recess is formed at a position that is in the axial position of the contact point P of the raceway surface 4 of the inner ring 10 with the rolling element 5. A portion 13A is provided.
Also in this case, an increase in the hoop stress of the inner ring raceway surface 4 due to the press-fitting of the inner ring 10 into the hub ring shaft portion 9b can be suppressed without increasing the thickness in the radial direction or the width direction of the inner ring 10.

  In addition, although the said embodiment demonstrated about the case where it applied to the wheel bearing apparatus for a driven wheel support, the wheel bearing apparatus of this invention is applicable also for driving wheel support.

It is sectional drawing of the wheel bearing apparatus concerning one Embodiment of this invention. It is an expanded sectional view of the A section in FIG. It is sectional drawing which shows the other structural example of A part. It is sectional drawing of the wheel bearing apparatus concerning other embodiment of this invention. It is an expanded sectional view of the B section in FIG. It is sectional drawing which shows the other structural example of the B section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer member 2 ... Inner member 3, 4 ... Raceway surface 5 ... Rolling element 9 ... Hub ring 9a ... Flange 9b for wheel attachment ... Shaft part 9d of hub wheel ... Clamping part 10 ... Inner ring 12, 12A, 13, 13A ... dent

Claims (5)

An outer member having a double-row raceway surface on the inner periphery and attached to the vehicle body, a double-row raceway surface facing the raceway surface on the outer periphery, and a wheel mounting flange on the outer periphery of the outboard side end An inner member, and a double row rolling element interposed between the outer member and the raceway surface of the inner member, and the inner member includes a hub ring having the flange and an inner portion of a shaft portion of the hub ring. In the wheel bearing device comprising an inner ring press-fitted into the outer periphery of the board side end,
A bearing device for a wheel, characterized in that an annular recess is provided on an inner diameter surface of the inner ring in an axial range in which a raceway surface of the inner ring is provided. An outer member having a double-row raceway surface on the inner periphery and attached to the vehicle body, a double-row raceway surface facing the raceway surface on the outer periphery, and a wheel mounting flange on the outer periphery of the outboard side end An inner member, and a double row rolling element interposed between the outer member and the raceway surface of the inner member, and the inner member includes a hub ring having the flange and an inner portion of a shaft portion of the hub ring. In a wheel mounting bearing device composed of an inner ring press-fitted into the outer periphery of the board side end,
A bearing device for a wheel, characterized in that an annular recess is provided on an inner ring fitting surface of the hub wheel in an axial range where a raceway surface of the inner ring is provided.   3. The wheel bearing according to claim 1, wherein the inner member is a member in which the inner ring is tightened in the axial direction with respect to the hub wheel by a crimping portion provided on an outer periphery of an inboard side end of the hub wheel. apparatus.   The wheel bearing device according to any one of claims 1 to 3, wherein a depth of the recessed portion is 0.1 to 1 mm.   5. The angular ball bearing type wheel bearing device according to claim 1, wherein an axial position of the recessed portion is an axial position of a contact point of the inner ring raceway surface with a rolling element. 6. The wheel bearing device which is a position which hangs on.

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