Bearing device for wheel

Abstract

The utility model provides a bearing device for a wheel. The bearing device for the wheel can fully restrain generation of edge loads and can enable grinding machinability of an auxiliary track face to be good. A bearing device (1) for a wheel is provided with: an outer member having outer raceway surfaces (2c, 2d); an inner member having inner raceway surfaces (3c, 4a); and rolling elements which are accommodated so as to be capable of rolling between the outer raceway surfaces (2c, 2d) and the inner raceway surfaces (3c, 4a), and which are configured so that, on at least one of the outer raceway surfaces (2c, 2d) and the inner raceway surfaces (3c, 4a), the radial distance between imaginary lines (alpha1, beta1) extending in the axial direction from the starting end positions of the auxiliary raceway surfaces (2i, 3i, 4i) and the groove bottom positions (2k, 3k, 4k) is 30% or more and 45% or more of the diameter of the rolling elements.

Description

Technical Field

[0001] The present utility model relates to the technology of bearing devices for wheels. Background Art

[0002] Conventionally, as a bearing device for a wheel of a motor vehicle, a double-row angular contact ball bearing is generally used. The bearing device for a wheel includes an outer ring, an inner ring, and balls held by raceways formed on the outer ring and the inner ring, respectively.

[0003] In addition, in the bearing device for a wheel, there is a bearing device for a wheel in which a chamfered portion having an arc-shaped cross section (a cross section passing through and parallel to the rotation axis) is provided at the edge of each raceway surface of the outer ring and the inner ring to reduce the generation of edge loads. However, in this bearing device for a wheel, when the load has a moment load, the contact angle of each raceway surface of the outer ring and the inner ring with respect to the ball increases, and a contact ellipse is generated at the position where each raceway surface of the outer ring and the inner ring contacts the ball. And, in such a case where the moment load is large, sometimes the contact ellipse extends to the chamfered portion to generate an edge load.

[0004] Here, in the case where a chamfered portion or the like is formed on the raceway surface by grinding using a grindstone, the grindstone is moved relative to the raceway surface in the radial direction (a direction orthogonal to the rotation axis of the bearing device for a wheel). Therefore, the closer the inclination angle of the chamfered portion or the like is to parallel with respect to the radial direction, the longer the time for grinding the raceway surface. And, in order not to let the contact ellipse extend to the chamfered portion, it is considered to reduce the inner diameter of the outer ring, increase the outer diameter of the inner ring, etc. However, in such a configuration, the inclination angle of the chamfered portion or the like is closer to parallel with respect to the radial direction, and the time for grinding the raceway surface increases.

[0005] As such a bearing device for a wheel that suppresses the generation of edge loads and also reduces the grinding time of the raceway surface, the following technology is known: an auxiliary raceway surface is provided at the edge of the higher one of the shoulders of the cross section of each raceway surface of the outer ring and the inner ring, and the auxiliary raceway surface is continuous from the curved surface constituting the raceway surface and has a cross-sectional shape formed by a curve or a straight line having a smaller curvature than the curve in the cross-sectional shape of the curved surface (see Patent Document 1).

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-52784 Summary of the Utility Model

[0009] Problems to be Solved by the Utility Model

[0010] However, in the bearing device for a wheel, the starting position of the auxiliary raceway surface at the boundary between the curved surface serving as the raceway surface and the auxiliary raceway surface is not clearly formed. Therefore, when the contact ellipse extends to the auxiliary raceway surface under a relatively large moment load, the generation of edge load sometimes cannot be sufficiently suppressed.

[0011] In addition, in the bearing device for a wheel, the starting position of the auxiliary raceway surface of the raceway surface is not clearly formed. Therefore, the range of the inclination angle when forming the auxiliary raceway surface is large, and sometimes the grinding time of the auxiliary raceway surface increases.

[0012] The present utility model has been completed in view of the above situation, and the problem is to provide a bearing device for a wheel that can more reliably suppress the generation of edge load and can also improve the grindability of the auxiliary raceway surface.

[0013] Solution to the problem

[0014] That is, a bearing device for a wheel includes:

[0015] An outer member having an outer raceway surface on its inner circumference;

[0016] An inner member having an inner raceway surface facing the outer raceway surface; and

[0017] Rolling elements that are rotatably accommodated between the outer raceway surface and the inner raceway surface,

[0018] wherein,

[0019] At least one of the raceway surfaces of the outer raceway surface and the inner raceway surface has an auxiliary raceway surface. The auxiliary raceway surface is provided at the edge portion on the higher shoulder side of the cross section passing through the rotation axis of the bearing device for a wheel and parallel to the rotation axis, is continuous from the curved surface constituting the corresponding raceway surface, and has a cross-sectional shape formed by a curve or a straight line having a smaller curvature than the curve in the cross-sectional shape of the curved surface.

[0020] The radial distance between the imaginary line extending axially from the starting position of the auxiliary raceway surface, which is the boundary between the curved surface and the auxiliary raceway surface, and the bottom position of the groove, which is the deepest position in the corresponding raceway surface, is configured to be 30% or more and 45% or less of the diameter of the rolling element.

[0021] Effects of the utility model

[0022] As an effect of the present utility model, the following effects are achieved.

[0023] That is, according to the bearing device for a wheel of the present utility model, the generation of edge load can be sufficiently suppressed, and in addition, the grindability of the auxiliary raceway surface can be made good. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a cross-sectional view showing a bearing device for a wheel according to an embodiment of the present utility model.

[0025] Figure 2 It is an enlarged cross-sectional view showing the outer ring of the bearing device for a wheel in the same manner.

[0026] Figure 3 It is an enlarged cross-sectional view showing the outer ring of the bearing device for a wheel in the same manner.

[0027] Figure 4 It is an enlarged cross-sectional view showing the hub ring of the bearing device for a wheel in the same manner.

[0028] Figure 5 It is an enlarged cross-sectional view showing the inner ring of the bearing device for a wheel in the same manner.

[0029] Figure 6 It is an enlarged cross-sectional view showing the bearing device for a wheel in the same manner.

[0030] Figure 7 It is an enlarged cross-sectional view showing the bearing device for a wheel in the same manner.

[0031] Figure 8 It is an enlarged cross-sectional view showing the bearing device for a wheel in the same manner.

[0032] Figure 9 It is an enlarged cross-sectional view showing the bearing device for a wheel in the same manner.

[0033] DESCRIPTION OF REFERENCE NUMERALS

[0034] 1 Bearing device for a wheel

[0035] 2 Outer ring

[0036] 2a Inner side opening

[0037] 2b Outer side opening

[0038] 2c (Inner side) outer raceway surface

[0039] 2d (Outer side) outer raceway surface

[0040] 2g Edge

[0041] 2h Curved surface

[0042] 2i Auxiliary raceway surface

[0043] 2j Grinding surface

[0044] 2k groove bottom position

[0045] 3 wheel hub

[0046] 3a small diameter stepped portion

[0047] 3b wheel mounting flange

[0048] 3c inner raceway surface

[0049] 3f outer peripheral surface

[0050] 3g edge portion

[0051] 3h curved surface

[0052] 3i auxiliary raceway surface

[0053] 3j grinding surface

[0054] 3k groove bottom position

[0055] 4 inner ring

[0056] 4a inner raceway surface

[0057] 4g edge portion

[0058] 4h curved surface

[0059] 4i auxiliary raceway surface

[0060] 4j grinding surface

[0061] 4k groove bottom position

[0062] 5 inner side ball row

[0063] 6 outer side ball row

[0064] 7 ball

[0065] 8 retainer. Detailed implementation manners

[0066] Hereinafter, the present detailed implementation manners will be described with reference to the accompanying drawings.

[0067] Figure 1 The illustrated wheel bearing device 1 is an embodiment of the wheel bearing device of the present utility model, and supports a wheel rotatably in a suspension device of a vehicle such as a motor vehicle.

[0068] As Figure 1As shown, the wheel bearing device 1 has a structure known as the third generation, and includes an outer ring 2 as an outer member, a hub ring 3 and an inner ring 4 as inner members, a double-row inner-side ball row 5 and an outer-side ball row 6 as rolling rows, a magnetic encoder 10, and an outer-side seal member 11.

[0069] Here, the inner side refers to the vehicle body side of the wheel bearing device 1 when installed on the vehicle body, and the outer side refers to the wheel side of the wheel bearing device 1 when installed on the vehicle body. In addition, the axial direction refers to the direction along the rotation axis of the wheel bearing device 1. One axial end side is the outer side, and the other axial end side is the inner side. In addition, the direction orthogonal to the rotation axis of the wheel bearing device 1 is represented as the radial direction. In addition, hereinafter, the "section" will be described as a section passing through the rotation axis of the wheel bearing device 1 and parallel to the rotation axis of the wheel bearing device 1.

[0070] On the inner peripheral surface of the outer ring 2, an inner-side outer raceway surface 2c and an outer-side outer raceway surface 2d are formed. On the outer peripheral surface of the outer ring 2, a vehicle body mounting flange for mounting the outer ring 2 to a vehicle body side member is integrally formed, and bolt holes for inserting a fastening connection member for fastening and connecting the vehicle body side member and the outer ring are provided in the vehicle body mounting flange.

[0071] On the inner-side end portion of the outer peripheral surface 3f of the hub ring 3, a small-diameter stepped portion 3a having a diameter smaller than that of the outer-side end portion is formed. On the outer-side end portion of the hub ring 3, a wheel mounting flange 3b for mounting a wheel is integrally formed. A plurality of bolt holes 3d are formed in the wheel mounting flange 3b. A hub bolt 3e for fastening and connecting the hub ring 3 to the wheel or a brake component is press-fitted into the bolt hole 3d. The wheel mounting flange 3b is an example of a hub flange extending radially outward.

[0072] On the outer peripheral surface 3f of the hub ring 3, an outer-side inner raceway surface 3c is provided so as to face the outer-side outer raceway surface 2d of the outer ring 2. That is, on the outer side of the inner member, the inner raceway surface 3c is constituted by the hub ring 3. The annular space formed by the outer-side end portion of the outer ring 2 and the hub ring 3 is configured as an outer-side opening 2b. An outer-side seal member 11 is fitted in the outer-side opening 2b.

[0073] The inner ring 4 is arranged on the small-diameter stepped portion 3a of the hub ring 3. The inner ring 4 is fixed to the small-diameter stepped portion 3a of the hub ring 3 by press-fitting or riveting. The inner ring 4 applies preload to the inner-side ball row 5 and the outer-side ball row 6 which are rolling rows. On the outer peripheral surface of the inner ring 4, an inner-side inner raceway surface 4a is arranged in a manner opposed to the outer raceway surface 2c on the inner side of the outer ring 2. That is, on the inner side of the inner member, the inner-side inner raceway surface 4a is constituted by the inner ring 4. The annular space formed by the inner end portion of the outer ring 2 and the inner ring 4 is configured as an inner-side opening 2a. A magnetic encoder 10 is arranged in the inner-side opening 2a via a support ring 9.

[0074] The inner-side ball row 5 and the outer-side ball row 6 which are rolling rows are constituted by holding a plurality of balls 7 serving as rolling elements by a cage 8. The inner-side ball row 5 is rotatably held between the inner-side inner raceway surface 4a of the inner ring 4 and the outer raceway surface 2c on the inner side of the outer ring 2. The outer-side ball row 6 is rotatably held between the inner raceway surface 3c of the hub ring 3 and the outer raceway surface 2d on the outer side of the outer ring 2. That is, the inner-side ball row 5 and the outer-side ball row 6 are rotatably accommodated between the two raceway surfaces of the outer member and the inner member. In the wheel bearing device 1, a double-row angular contact ball bearing is constituted by the outer ring 2, the hub ring 3, the inner ring 4, the inner-side ball row 5, and the outer-side ball row 6. In addition, in the wheel bearing device 1, the outer raceway surfaces 2c, 2d and the inner raceway surfaces 3c, 4a are formed such that the contact angles with respect to the balls 7 of the inner-side ball row 5 or the outer-side ball row 6 are back-to-back. The contact angles of the outer raceway surfaces 2c, 2d and the inner raceway surfaces 3c, 4a with respect to the balls 7 of the inner-side ball row 5 or the outer-side ball row 6 are set, for example, in the range of 10 to 45 degrees with respect to the radial direction.

[0075] As Figure 2 Or Figure 3 shown, the outer raceway surfaces 2c, 2d of the outer ring 2 respectively have a curved surface 2h, a flange portion 2g, an auxiliary raceway surface 2i, a grinding surface 2j, and a groove bottom position 2k.

[0076] The cross-section forming the outer raceway surfaces 2c and 2d of the curved surface 2h is formed in an arc shape. The edge portion 2g represents the edge portion on the higher shoulder side of the cross-section of the outer raceway surfaces 2c and 2d. The edge portion 2g is formed on the outer side in the outer raceway surface 2c and on the inner side in the outer raceway surface 2d. The auxiliary raceway surface 2i and the grinding surface 2j are provided on the edge portion 2g. The auxiliary raceway surface 2i and the grinding surface 2j are formed by grinding the auxiliary raceway surface 2i using a grinding stone. At this time, by moving the grinding stone relative to the auxiliary raceway surface 2i in the radial direction, the auxiliary raceway surface 2i and the grinding surface 2j are formed on the auxiliary raceway surface 2i. The cross-section of the auxiliary raceway surface 2i forming the outer raceway surfaces 2c and 2d is continuous from the arc-shaped curved surface 2h and has a cross-sectional shape composed of a curve or a straight line with a smaller curvature compared to the curve in the cross-sectional shape of the curved surface 2h. The auxiliary raceway surface 2i has a cross-sectional shape composed of a straight line in the present embodiment. The grinding surface 2j is formed in a continuous manner from the auxiliary raceway surface 2i. The boundary portion between the curved surface 2h and the auxiliary raceway surface 2i is configured as the start position 2is of the auxiliary raceway surface 2i, and the boundary portion between the auxiliary raceway surface 2i and the grinding surface 2j is configured as the end position 2ie of the auxiliary raceway surface 2i. The groove bottom position 2k represents the deepest position in the outer raceway surfaces 2c and 2d and is located at the outermost position in the radial direction of the outer raceway surfaces 2c and 2d. The start position 2is in the outer raceway surfaces 2c and 2d is located on the outer diameter side relative to the end position 2ie.

[0077] As Figure 4 shown, the inner raceway surface 3c of the hub ring 3 has a curved surface 3h, an edge portion 3g, an auxiliary raceway surface 3i, a grinding surface 3j, and a groove bottom position 3k.

[0078] The cross-section of the inner raceway surface 3c that constitutes the curved surface 3h is formed in an arc shape. The edge portion 3g represents the edge portion on the higher shoulder side of the cross-section of the inner raceway surface 3c. The edge portion 3g is formed on the outer side of the inner raceway surface 3c. The auxiliary raceway surface 3i and the grinding surface 3j are provided on the edge portion 3g. The auxiliary raceway surface 3i and the grinding surface 3j are formed by grinding the auxiliary raceway surface 3i using a grinding stone. At this time, by moving the grinding stone relative to the auxiliary raceway surface 3i in the radial direction, the auxiliary raceway surface 3i and the grinding surface 3j are formed on the auxiliary raceway surface 3i. The cross-section of the inner raceway surface 3c that constitutes the auxiliary raceway surface 3i is continuous from the arc-shaped curved surface 3h and has a cross-sectional shape composed of a curve or a straight line with a smaller curvature compared to the curve in the cross-sectional shape of the curved surface 3h. The auxiliary raceway surface 3i has a cross-sectional shape composed of a straight line in the present embodiment. The grinding surface 3j is formed so as to be continuous from the auxiliary raceway surface 3i. The boundary portion between the curved surface 3h and the auxiliary raceway surface 3i is configured as the start position 3is of the auxiliary raceway surface 3i, and the boundary portion between the auxiliary raceway surface 3i and the grinding surface 3j is configured as the end position 3ie of the auxiliary raceway surface 3i. The groove bottom position 3k represents the deepest position in the inner raceway surface 3c and is located at the innermost position in the radial direction of the inner raceway surface 3c. The start position 3is in the inner raceway surface 3c is located on the inner diameter side of the end position 3ie.

[0079] As Figure 5 shown, the inner raceway surface 4a of the inner ring 4 has a curved surface 4h, an edge portion 4g, an auxiliary raceway surface 4i, a grinding surface 4j, and a groove bottom position 4k.

[0080] The cross-section of the inner raceway surface 4a that constitutes the curved surface 4h is formed in an arc shape. The edge portion 4g represents the edge portion on the side with a higher shoulder in the cross-section of the inner raceway surface 4a. The edge portion 4g is formed on the inner side of the inner raceway surface 4a. The auxiliary raceway surface 4i and the grinding surface 4j are provided on the edge portion 4g. The auxiliary raceway surface 4i and the grinding surface 4j are formed by grinding the auxiliary raceway surface 4i using a grindstone. At this time, by moving the grindstone radially relative to the auxiliary raceway surface 4i, the auxiliary raceway surface 4i and the grinding surface 4j are formed on the auxiliary raceway surface 4i. The cross-section of the inner raceway surface 4a that constitutes the auxiliary raceway surface 4i is continuous from the arc-shaped curved surface 4h and has a cross-sectional shape composed of a curve or a straight line with a smaller curvature than the curve in the cross-sectional shape of the curved surface 4h. In the present embodiment, the auxiliary raceway surface 4i has a cross-sectional shape composed of a straight line. The grinding surface 4j is formed so as to be continuous from the auxiliary raceway surface 4i. The boundary portion between the curved surface 4h and the auxiliary raceway surface 4i is configured as the start position 4is of the auxiliary raceway surface 4i, and the boundary portion between the auxiliary raceway surface 4i and the grinding surface 4j is configured as the end position 4ie of the auxiliary raceway surface 4i. The groove bottom position 4k represents the deepest position in the inner raceway surface 4a and is located at the innermost position in the radial direction of the inner raceway surface 4a. The start position 4is in the inner raceway surface 4c is located on the inner diameter side with respect to the end position 4ie.

[0081] In the wheel bearing device 1 configured as described above, when the contact angle of the outer raceway surfaces 2c, 2d and the inner raceway surfaces 3c, 4a with respect to the balls 7 of the inner side ball row 5 or the outer side ball row 6 increases due to a relatively large moment load, the contact ellipse extends from the outer raceway surfaces 2c, 2d and the inner raceway surfaces 3c, 4a to the auxiliary raceway surfaces 2i, 3i, 4i. And, since the auxiliary raceway surfaces 2i, 3i, 4i are continuous from the curved surfaces 2h, 3h, 4h and have a cross-sectional shape composed of a curve or a straight line with a smaller curvature than the curve in the cross-sectional shape of the curved surfaces 2h, 3h, 4h, when the contact ellipse extends to the auxiliary raceway surfaces 2i, 3i, 4i due to a relatively large moment load, edge load generation can be suppressed.

[0082] In addition, in the wheel bearing device 1 configured as described above, since the auxiliary raceway surfaces 2i, 3i, 4i have a cross-sectional shape composed of a curve or a straight line with a smaller curvature than the curve in the cross-sectional shape of the curved surfaces 2h, 3h, 4h, compared with the case where the curved surfaces 2h, 3h, 4h are directly extended to form the auxiliary raceway surfaces, the inclination with respect to the radial direction can be made relatively large, and the grindability of the auxiliary raceway surfaces 2i, 3i, 4i can be made good.

[0083] As Figure 2As shown, the radial distance H1 between the imaginary line α1 extending axially from the starting position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k (the height distance from the groove bottom position 2k to the starting position 2is of the auxiliary raceway surface 2i in the radial direction) is configured to be 30% or more of the diameter Di of the balls 7 in the inner side ball row 5. That is, the radial distance H1 between the imaginary line α1 extending axially from the starting position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k satisfies the relationship H1 / Di≥0.30.

[0084] By configuring in this way, when the contact ellipse extends to the auxiliary raceway surface 2i under a relatively large moment load, the generation of edge load can be more reliably suppressed.

[0085] As Figure 3 shown, the radial distance H3 between the imaginary line α3 extending axially from the starting position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k (the height distance from the groove bottom position 2k to the starting position 2is of the auxiliary raceway surface 2i in the radial direction) is configured to be 30% or more of the diameter Do of the balls 7 in the outer side ball row 6. That is, the radial distance H3 between the imaginary line α3 extending axially from the starting position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k satisfies the relationship H3 / Do≥0.30.

[0086] By configuring in this way, when the contact ellipse extends to the auxiliary raceway surface 2i under a relatively large moment load, the generation of edge load can be more reliably suppressed.

[0087] As Figure 4 shown, the radial distance H5 between the imaginary line β1 extending axially from the starting position 3is of the auxiliary raceway surface 3i and the groove bottom position 3k (the height distance from the groove bottom position 3k to the starting position 3is of the auxiliary raceway surface 3i in the radial direction) is configured to be 30% or more of the diameter Do of the balls 7 in the outer side ball row 6. That is, the radial distance H5 between the imaginary line β1 extending axially from the starting position 3is of the auxiliary raceway surface 3i and the groove bottom position 3k satisfies the relationship H5 / Do≥0.30.

[0088] By configuring in this way, when the contact ellipse extends to the auxiliary raceway surface 3i under a relatively large moment load, the generation of edge load can be more reliably suppressed.

[0089] As Figure 5As shown, the radial distance H7 between the imaginary line β3 extending axially from the start position 4is of the auxiliary raceway surface 4i and the groove bottom position 4k (the height distance from the groove bottom position 4k to the start position 4is of the auxiliary raceway surface 4i in the radial direction) is configured to be 30% or more of the diameter Di of the ball 7 of the inner side ball row 5. That is, the radial distance H7 between the imaginary line β3 extending axially from the start position 4is of the auxiliary raceway surface 4i and the groove bottom position 4k satisfies the relationship H7 / Di≥0.30.

[0090] By configuring it in this way, when the contact ellipse extends to the auxiliary raceway surface 4i under a relatively large moment load, the generation of edge load can be more reliably suppressed.

[0091] In addition, by providing the auxiliary raceway surfaces 2i on the outer raceway surfaces 2c, 2d of the outer member (outer ring 2) and the auxiliary raceway surfaces 3i, 4i on the inner raceway surfaces 3c, 4a of the inner member (hub ring 3 and inner ring 4) as described above, the generation of edge load can be further more reliably suppressed. However, it is not limited to such a structure, and it can also be configured to provide the auxiliary raceway surfaces 2i, 3i, 4i on only one of the outer member and the inner member.

[0092] In addition, by providing the auxiliary raceway surfaces 2i on the outer raceway surfaces 2c, 2d of the outer ring 2 respectively as described above, the generation of edge load can be further more reliably suppressed. However, it is not limited to such a structure, and it can also be configured to provide the auxiliary raceway surface 2i on only one of the outer raceway surfaces 2c, 2d of the outer ring 2.

[0093] In addition, by providing the auxiliary raceway surface 3i on the inner raceway surface 3c of the hub ring 3 and the auxiliary raceway surface 4i on the inner raceway surface 4a of the inner ring 4 as described above, the generation of edge load can be further more reliably suppressed. However, it is not limited to such a structure, and it can also be configured to provide the auxiliary raceway surfaces 3i, 4i on only one of the inner raceway surface 3c of the hub ring 3 and the inner raceway surface 4a of the inner ring 4.

[0094] As Figure 2 shown, the radial distance H1 between the imaginary line α1 extending axially from the start position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k is configured to be 45% or less of the diameter Di of the ball 7 of the inner side ball row 5. That is, the radial distance H1 between the imaginary line α1 extending axially from the start position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k satisfies the relationship H1 / Di≤0.45.

[0095] By configuring it in this way, an increase in the grinding time of the auxiliary raceway surface 2i can be suppressed, and the grindability of the auxiliary raceway surface 2i can be more reliably improved.

[0096] As Figure 3 shown, the radial distance H3 between the imaginary line α3 extending axially from the start position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k is configured to be 45% or less of the diameter Do of the ball 7 in the outer side ball row 6. That is, the radial distance H3 between the imaginary line α3 extending axially from the start position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k satisfies the relationship of H3 / Do ≤ 0.45.

[0097] By configuring in this way, it is possible to suppress an increase in the grinding time of the auxiliary raceway surface 2i and make the grindability of the auxiliary raceway surface 2i more reliably good.

[0098] As Figure 4 shown, the radial distance H5 between the imaginary line β1 extending axially from the start position 3is of the auxiliary raceway surface 3i and the groove bottom position 3k is configured to be 45% or less of the diameter Do of the ball 7 in the outer side ball row 6. That is, the radial distance H5 between the imaginary line β1 extending axially from the start position 3is of the auxiliary raceway surface 3i and the groove bottom position 3k satisfies the relationship of H5 / Do ≤ 0.45.

[0099] By configuring in this way, it is possible to suppress an increase in the grinding time of the auxiliary raceway surface 3i and make the grindability of the auxiliary raceway surface 3i more reliably good.

[0100] As Figure 5 shown, the radial distance H7 between the imaginary line β3 extending axially from the start position 4is of the auxiliary raceway surface 4i and the groove bottom position 4k is configured to be 45% or less of the diameter Di of the ball 7 in the inner side ball row 5. That is, the radial distance H7 between the imaginary line β3 extending axially from the start position 4is of the auxiliary raceway surface 4i and the groove bottom position 4k satisfies the relationship of H7 / Di ≤ 0.45.

[0101] By configuring in this way, it is possible to suppress an increase in the grinding time of the auxiliary raceway surface 4i and make the grindability of the auxiliary raceway surface 4i more reliably good.

[0102] As Figure 2 shown, the radial distance H2 between the imaginary line α2 extending axially from the end position 2ie of the auxiliary raceway surface 2i and the groove bottom position 2k (the height distance from the groove bottom position 2k to the end position 2ie of the auxiliary raceway surface 2i in the radial direction) is configured to be 50% or less of the diameter Di of the ball 7 in the inner side ball row 5. That is, the radial distance H2 between the imaginary line α2 extending axially from the end position 2ie of the auxiliary raceway surface 2i and the groove bottom position 2k satisfies the relationship of H2 / Di ≤ 0.50.

[0103] By configuring in this way, it is possible to suppress an increase in the grinding time of the auxiliary raceway surface 2i, and the grindability of the auxiliary raceway surface 4i can be made more reliably good.

[0104] As Figure 3 shown, the radial distance H4 from the imaginary line α4 extending axially from the terminal position 2ie of the auxiliary raceway surface 2i to the groove bottom position 2k (the distance from the groove bottom position 2k to the height of the terminal position 2ie of the auxiliary raceway surface 2i in the radial direction) is configured to be 50% or less of the diameter Do of the balls 7 in the outer side ball row 6. That is, the radial distance H4 from the imaginary line α4 extending axially from the terminal position 2ie of the auxiliary raceway surface 2i to the groove bottom position 2k satisfies the relationship H4 / Do ≤ 0.50.

[0105] By configuring in this way, it is possible to suppress an increase in the grinding time of the auxiliary raceway surface 2i, and the grindability of the auxiliary raceway surface 4i can be made more reliably good.

[0106] As Figure 4 shown, the radial distance H6 from the imaginary line β2 extending axially from the terminal position 3ie of the auxiliary raceway surface 3i to the groove bottom position 3k (the distance from the groove bottom position 3k to the height of the terminal position 3ie of the auxiliary raceway surface 3i in the radial direction) is configured to be 50% or less of the diameter Do of the balls 7 in the outer side ball row 6. That is, the radial distance H6 from the imaginary line β2 extending axially from the terminal position 3ie of the auxiliary raceway surface 3i to the groove bottom position 3k satisfies the relationship H6 / Do ≤ 0.50.

[0107] By configuring in this way, it is possible to suppress an increase in the grinding time of the auxiliary raceway surface 3i, and the grindability of the auxiliary raceway surface 3i can be made more reliably good.

[0108] As Figure 5 shown, the radial distance H8 from the imaginary line β4 extending axially from the terminal position 4ie of the auxiliary raceway surface 4i to the groove bottom position 4k (the distance from the groove bottom position 4k to the height of the terminal position 4ie of the auxiliary raceway surface 4i in the radial direction) is configured to be 50% or less of the diameter Di of the balls 7 in the inner side ball row 5. That is, the radial distance H8 from the imaginary line β4 extending axially from the terminal position 4ie of the auxiliary raceway surface 4i to the groove bottom position 4k satisfies the relationship H8 / Di ≤ 0.50.

[0109] By configuring in this way, it is possible to suppress an increase in the grinding time of the auxiliary raceway surface 4i, and the grindability of the auxiliary raceway surface 4i can be made more reliably good.

[0110] It should be noted that the diameter Di of the balls 7 in the inner-side ball row 5 and the diameter Do of the balls 7 in the outer-side ball row 6 can be formed with different values, or can also be formed with the same value. In addition, the distance H1 and the distance H3 can be formed with different values, or can also be formed with the same value. The distance H5 and the distance H7 can be formed with different values, or can also be formed with the same value. The distance H2 and the distance H4 can be formed with different values, or can also be formed with the same value. The distance H6 and the distance H8 can be formed with different values, or can also be formed with the same value.

[0111] The average roughness values of the auxiliary raceway surfaces 2i, 3i, and 4i are configured to be larger than the average roughness value of the curved surface 2h. By configuring in this way, it is possible to easily hold the grease base oil on the auxiliary raceway surfaces 2i, 3i, and 4i, and more reliably prevent the occurrence of surface-originated spalling.

[0112] In addition, it is preferable to set the average roughness Ra of the curved surfaces 2h, 3h, and 4h to 0.07 μm or less, and configure the average roughness Ra of the auxiliary raceway surfaces 2i, 3i, and 4i to be 15 times or more and 30 times or less the average roughness Ra of the curved surfaces 2h, 3h, and 4h. By configuring in this way, it is thus possible to more reliably hold the grease base oil on the auxiliary raceway surfaces 2i, 3i, and 4i more easily.

[0113] As Figure 6 shown, the grinding surfaces 2j, 4j are formed into a conical shape inclined at an angle close to parallel with respect to the axial direction by performing grinding with a grindstone on the ends of the auxiliary raceway surfaces 2i, 4i. In addition, similarly, the grinding surface 3j can also be formed into a conical shape inclined at an angle close to parallel with respect to the axial direction by performing grinding with a grindstone on the end of the auxiliary raceway surface 3i. In addition, as Figure 7 shown, the grinding surfaces 2j, 4j can also be formed into a chamfered shape in which the ends of the auxiliary raceway surfaces 2i, 4i are chamfered by performing grinding with a grindstone on the ends of the auxiliary raceway surfaces 2i, 4i. In addition, similarly, the grinding surface 3j can also be formed into a chamfered shape in which the end of the auxiliary raceway surface 3j is chamfered by performing grinding with a grindstone on the end of the auxiliary raceway surface 3j.

[0114] It is also possible to form either one of the grinding surface 2j of the outer member (outer ring 2) and the grinding surfaces 3j, 4j of the inner members (hub outer ring 3 and inner ring 4) into a chamfered shape and form the other into a conical shape. That is, as Figure 8 shown, it is also possible to form the grinding surface 2j of the outer ring 2 into a conical shape and form the grinding surface 4j of the inner ring 4 into a chamfered shape. In addition, similarly, it is also possible to form the grinding surface 2j of the outer ring 2 into a conical shape and form the grinding surface 3j of the hub outer ring 3 into a chamfered shape. In addition, asFigure 9 As shown, the grinding surface 2j of the outer ring 2 can also be configured as a chamfered shape, and the grinding surface 4j of the inner ring 4 can be configured as a conical shape. Similarly, the grinding surface 2j of the outer ring 2 can be configured as a chamfered shape, and the grinding surface 3j of the hub outer ring 3 can be configured as a conical shape.

[0115] The embodiments of the present invention have been described above. However, the present invention is in no way limited to such embodiments, but is merely illustrative. Of course, it can be further implemented in various ways without departing from the gist of the present invention. The scope of the present invention is shown by the description of the patent technical solution, and also includes the equivalent meanings and all changes within the scope recorded in the patent technical solution.

Claims

1. A wheel bearing device, comprising: An outer member having an outer track surface on the inner periphery; an inner member having an inner track surface opposite to the outer track surface; and A rolling element is accommodated between the outer raceway surface and the inner raceway surface so as to roll freely. It is characterized in that At least one of the outer and inner raceways has an auxiliary raceway, the auxiliary raceway being provided at an edge portion of a section that passes through the rotation axis of the wheel bearing device and is parallel to the rotation axis and has a higher shoulder, and is continuous from a curved surface constituting the corresponding raceway, and has a cross-sectional shape that is composed of a curve or a straight line having a smaller curvature than a curve in the cross-sectional shape of the curved surface, The radial distance between an imaginary line extending axially from the starting end position of the auxiliary raceway surface as the boundary portion between the curved surface and the auxiliary raceway surface and the groove bottom position as the deepest position in the corresponding raceway surface is greater than or equal to 30% and less than or equal to 45% of the diameter of the rolling element.

2. The wheel bearing device according to claim 1, characterized in that: At least one of the outer raceway surface and the inner raceway surface has a grinding surface continuous from the auxiliary raceway surface, and the radial distance between an imaginary line extending axially from a terminal position serving as a boundary portion between the auxiliary raceway surface and the grinding surface and the groove bottom position is less than 50% of the diameter of the rolling element.

3. The wheel bearing device according to claim 1 or 2, characterized in that: The value of the average roughness of the auxiliary raceway surface is configured to be larger than the value of the average roughness of the curved surface.

4. The wheel bearing device according to claim 3, characterized in that: The average roughness Ra of the curved surface is 0.07 μm or less, and the average roughness Ra of the auxiliary raceway surface is 15 times or more and 30 times or less of the average roughness Ra of the curved surface.

Images