Bearing device for wheel

Abstract

The present invention provides a bearing device for a wheel, which can sufficiently suppress the generation of edge load and can improve the grinding machinability of an auxiliary raceway surface. 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 invention relates to a technology of a wheel bearing device. Background Art

[0002] Conventionally, double row angular contact ball bearings are generally used as wheel bearing devices for automobiles, and the wheel bearing devices include an outer ring, an inner ring, and balls held by raceway surfaces formed on the outer ring and the inner ring, respectively.

[0003] In addition, in the wheel bearing device, there is a wheel bearing device that reduces the generation of edge load by providing a chamfered portion with an arc-shaped cross section (a cross section that passes through the rotation axis and is parallel to the rotation axis) at the edge of the raceway surface of each of the outer ring and the inner ring. However, in this wheel bearing device, when the load is a moment load, the contact angle of the raceway surface of each of the outer ring and the inner ring relative to the ball increases, and a contact ellipse is generated at the position where the raceway surface of each of the outer ring and the inner ring contacts the ball. In addition, in the case of such a large moment load, the contact ellipse sometimes extends to the chamfered portion and generates an edge load.

[0004] Here, when a chamfered portion or the like is formed on the raceway surface by grinding with a grindstone, the grindstone is moved in the radial direction (direction orthogonal to the rotation axis of the wheel bearing device) relative to the raceway surface. 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 grinding time for the raceway surface increases. In addition, in order to prevent the contact ellipse from extending toward the chamfered portion, it is considered to reduce the inner diameter of the outer ring, increase the outer diameter of the inner ring, etc., but in the case of such a configuration, the inclination angle of the chamfered portion or the like is close to parallel with respect to the radial direction, and the grinding time for the raceway surface increases.

[0005] As a wheel bearing device that suppresses the generation of edge loads and reduces the time for grinding the raceway surface, the following technology is known: an auxiliary raceway surface is provided at the edge of the higher shoulder portion of the cross-section of the raceway surface of each of the outer ring and the inner ring, the auxiliary raceway surface being continuous from the curved surface constituting the raceway surface and having a cross-sectional shape consisting of 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 literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2004-52784 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, in the wheel bearing device, the starting position of the auxiliary track surface, which is the boundary portion between the curved surface of the track surface and the auxiliary track surface, is not clearly formed. Therefore, when a relatively large moment load is applied and the contact ellipse extends to the auxiliary track surface, the generation of edge loads cannot sometimes be fully suppressed.

[0011] In addition, in the wheel bearing device, the starting position of the auxiliary raceway surface of the raceway surface is not clearly formed, so the range of the inclination angle when forming the auxiliary raceway surface is wide, and the time for grinding the auxiliary raceway surface may increase.

[0012] The present invention has been made in view of the above-mentioned situation, and an object of the present invention is to provide a wheel bearing device which can more reliably suppress the generation of edge loads and can improve the grindability of the auxiliary raceway surface.

[0013] Solutions to Solve Problems

[0014] That is, a wheel bearing device comprises:

[0015] An outer member having an outer track surface on the inner periphery;

[0016] an inner member having an inner track surface opposite to the outer track surface; and

[0017] A rolling element is accommodated between the outer raceway surface and the inner raceway surface so as to roll freely.

[0018] in,

[0019] 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,

[0020] 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.

[0021] Effects of the Invention

[0022] The present invention has the following effects.

[0023] That is, according to the wheel bearing device of the present invention, the generation of edge load can be sufficiently suppressed, and the grindability of the auxiliary raceway surface can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0025] Figure 2 1 is an enlarged cross-sectional view similarly showing the outer ring of the wheel bearing device.

[0026] Figure 3 1 is an enlarged cross-sectional view similarly showing the outer ring of the wheel bearing device.

[0027] Figure 4 1 is an enlarged cross-sectional view similarly showing a hub wheel of the wheel bearing device.

[0028] Figure 5 This is an enlarged cross-sectional view similarly showing the inner ring of the wheel bearing device.

[0029] Figure 6 1 is an enlarged cross-sectional view similarly showing the wheel bearing device.

[0030] Figure 7 1 is an enlarged cross-sectional view similarly showing the wheel bearing device.

[0031] Figure 8 1 is an enlarged cross-sectional view similarly showing the wheel bearing device.

[0032] Fig. 9 1 is an enlarged cross-sectional view similarly showing the wheel bearing device.

[0033] Description of Reference Numerals

[0034] 1 Wheel bearing device

[0035] 2 Outer ring

[0036] 2a Inner opening

[0037] 2b External opening

[0038] 2c (Inner side) Outer track surface

[0039] 2d (outer side) outer track surface

[0040] 2g Edge

[0041] 2h Surface

[0042] 2i Auxiliary track surface

[0043] 2j Grinding surface

[0044] 2k Slot bottom position

[0045] 3 Wheel hub

[0046] 3a Small path steps

[0047] 3b Wheel mounting flange

[0048] 3c Inner track surface

[0049] 3f Outer Surface

[0050] 3g Edge

[0051] 3h Surface

[0052] 3i Auxiliary track surface

[0053] 3j Grinding surface

[0054] 3k Slot bottom position

[0055] 4 Inner ring

[0056] 4a Inner track surface

[0057] 4g edge

[0058] 4h Surface

[0059] 4i Auxiliary track surface

[0060] 4j Grinding surface

[0061] 4k slot bottom position

[0062] 5 Inner side ball row

[0063] 6 External side ball row

[0064] 7 Ball

[0065] 8 Retainer. DETAILED DESCRIPTION

[0066] Hereinafter, this specific embodiment will be described using the drawings.

[0067] Figure 1 The wheel bearing device 1 shown is one embodiment of the wheel bearing device of the present invention, and rotatably supports a wheel in a suspension device of a vehicle such as an automobile.

[0068] like Figure 1 As shown, the wheel bearing device 1 has a structure called 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 sealing 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, the following description is made by indicating 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] An inner outer raceway surface 2c and an outer outer raceway surface 2d are formed on the inner circumference of the outer ring 2. A vehicle body mounting flange for mounting the outer ring 2 on a vehicle body side member is integrally formed on the outer circumference of the outer ring 2, and a bolt hole for inserting a fastening member for fastening the vehicle body side member to the outer ring is provided on the vehicle body mounting flange.

[0071] A small-diameter stepped portion 3a having a smaller diameter than the outer side end is formed at the inner side end of the outer peripheral surface 3f of the hub ring 3. A wheel mounting flange 3b for mounting a wheel is integrally formed at the outer side end of the hub ring 3. A plurality of bolt holes 3d are formed in the wheel mounting flange 3b. Hub bolts 3e for fastening the hub ring 3 to the wheel or brake components are pressed into the bolt holes 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 inner track surface 3c on the outer side is provided in a manner opposite to the outer track surface 2d on the outer side of the outer ring 2. That is, on the outer side of the inner member, the inner track surface 3c is formed by the hub ring 3. The annular space formed by the outer side end of the outer ring 2 and the hub ring 3 constitutes the outer side opening 2b. The outer side sealing member 11 is embedded in the outer side opening 2b.

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

[0074] The inner ball row 5 and the outer ball row 6 as rolling rows are formed by holding a plurality of balls 7 as rolling elements by a retainer 8. The inner ball row 5 is freely sandwiched between the 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 ball row 6 is freely sandwiched 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 ball row 5 and the outer ball row 6 are freely accommodated between the two raceways of the outer member and the inner member. In the wheel bearing device 1, a double row angular contact ball bearing is formed by the outer ring 2, the hub ring 3 and the inner ring 4, the inner ball row 5 and the outer ball row 6. In addition, in the wheel bearing device 1, the outer raceways 2c, 2d and the inner raceways 3c, 4a are formed in a back-to-back manner with respect to the contact angle of the balls 7 of the inner ball row 5 or the outer ball row 6. The contact angles of the outer raceway surfaces 2c and 2d and the inner raceway surfaces 3c and 4a with respect to the balls 7 of the inner ball row 5 or the outer ball row 6 are set to be, for example, in the range of 10 to 45 degrees with respect to the radial direction.

[0075] like Figure 2 or Figure 3 As shown, the outer raceway surfaces 2c and 2d of the outer ring 2 each have a curved surface 2h, an edge portion 2g, an auxiliary raceway surface 2i, a ground surface 2j, and a groove bottom position 2k.

[0076] The cross section of the curved surface 2h constituting the outer raceway surfaces 2c and 2d is configured in an arc shape. The edge 2g represents the edge of the side where the shoulder of the cross section of the outer raceway surfaces 2c and 2d is higher. The edge 2g is formed on the outer side of the outer raceway surface 2c and on the inner side of the outer raceway surface 2d. The auxiliary raceway surface 2i and the grinding surface 2j are provided on the edge 2g. The auxiliary raceway surface 2i and the grinding surface 2j are formed by grinding the auxiliary raceway surface 2i using a grindstone. At this time, the auxiliary raceway surface 2i and the grinding surface 2j are formed on the auxiliary raceway surface 2i by moving the grindstone radially relative to the auxiliary raceway surface 2i. The cross section of the auxiliary raceway surface 2i constituting 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 having a smaller curvature than the curve in the cross-sectional shape of the curved surface 2h. In the present embodiment, the auxiliary raceway surface 2i has a cross-sectional shape composed of a straight line. The grinding surface 2j is formed in a manner continuous from the auxiliary raceway surface 2i. The boundary portion between the curved surface 2h and the auxiliary track surface 2i constitutes the starting position 2is of the auxiliary track surface 2i, and the boundary portion between the auxiliary track surface 2i and the grinding surface 2j constitutes the terminal position 2ie of the auxiliary track surface 2i. The groove bottom position 2k represents the deepest position in the outer track surfaces 2c and 2d, and is located at the radially outermost position of the outer track surfaces 2c and 2d. The starting position 2is in the outer track surfaces 2c and 2d is located at the outer diameter side than the terminal position 2ie.

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

[0078] The cross section of the curved surface 3h constituting the inner track surface 3c is configured in an arc shape. The edge 3g represents the edge of the side where the shoulder of the cross section of the inner track surface 3c is higher. The edge 3g is formed on the outer side of the inner track surface 3c. The auxiliary track surface 3i and the grinding surface 3j are provided on the edge 3g. The auxiliary track surface 3i and the grinding surface 3j are formed by grinding the auxiliary track surface 3i using a grindstone. At this time, the auxiliary track surface 3i and the grinding surface 3j are formed on the auxiliary track surface 3i by moving the grindstone radially relative to the auxiliary track surface 3i. The cross section of the auxiliary track surface 3i constituting the inner track surface 3c is continuous from the arc-shaped curved surface 3h, and has a cross-sectional shape composed of a curve or a straight line having a smaller curvature than the curve in the cross-sectional shape of the curved surface 3h. In the present embodiment, the auxiliary track surface 3i has a cross-sectional shape composed of a straight line. The grinding surface 3j is formed in a manner continuous from the auxiliary track surface 3i. The boundary portion between the curved surface 3h and the auxiliary track surface 3i constitutes the starting position 3is of the auxiliary track surface 3i, and the boundary portion between the auxiliary track surface 3i and the grinding surface 3j constitutes the terminal position 3ie of the auxiliary track surface 3i. The groove bottom position 3k indicates the deepest position in the inner track surface 3c and is located at the radially innermost position of the inner track surface 3c. The starting position 3is in the inner track surface 3c is located at a position closer to the inner diameter side than the terminal position 3ie.

[0079] like Figure 5 As 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 ground surface 4j, and a groove bottom position 4k.

[0080] The cross section of the inner track surface 4a of the curved surface 4h is formed in an arc shape. The edge 4g represents the edge of the side where the shoulder of the cross section of the inner track surface 4a is higher. The edge 4g is formed on the inner side of the inner track surface 4a. The auxiliary track surface 4i and the grinding surface 4j are provided on the edge 4g. The auxiliary track surface 4i and the grinding surface 4j are formed by grinding the auxiliary track surface 4i using a grindstone. At this time, the auxiliary track surface 4i and the grinding surface 4j are formed on the auxiliary track surface 4i by moving the grindstone radially relative to the auxiliary track surface 4i. The cross section of the inner track surface 4a of the auxiliary track 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 having a smaller curvature than the curve in the cross-sectional shape of the curved surface 4h. The auxiliary track surface 4i has a cross-sectional shape composed of a straight line in the present embodiment. The grinding surface 4j is formed in a manner continuous from the auxiliary track surface 4i. The boundary between the curved surface 4h and the auxiliary track surface 4i constitutes the starting position 4is of the auxiliary track surface 4i, and the boundary between the auxiliary track surface 4i and the grinding surface 4j constitutes the terminal position 4ie of the auxiliary track surface 4i. The groove bottom position 4k represents the deepest position in the inner track surface 4a and is located at the radially innermost position of the inner track surface 4a. The starting position 4is in the inner track surface 4c is located at the inner diameter side relative to the terminal position 4ie.

[0081] In the wheel bearing device 1 constructed as described above, when a relatively large moment load is applied and the contact angle of the outer raceway surface 2c, 2d and the inner raceway surface 3c, 4a with respect to the ball 7 of the inner ball row 5 or the outer ball row 6 increases, the contact ellipse extends from the outer raceway surface 2c, 2d and the inner raceway surface 3c, 4a to the auxiliary raceway surface 2i, 3i, 4i. Furthermore, the auxiliary raceway surface 2i, 3i, 4i is continuous from the curved surface 2h, 3h, 4h and has a cross-sectional shape composed of a curve or a straight line having a smaller curvature than the curve in the cross-sectional shape of the curved surface 2h, 3h, 4h, so that when a relatively large moment load is applied and the contact ellipse extends to the auxiliary raceway surface 2i, 3i, 4i, the generation of edge load can be suppressed.

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

[0083] like Figure 2As shown in FIG. 1 , the radial distance H1 between the imaginary line α1 extending in the axial direction from the starting end position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k (the distance of the height from the groove bottom position 2k to the starting end 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 ball 7 of the inner side ball row 5. That is, the radial distance H1 between the imaginary line α1 extending in the axial direction from the starting end position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k satisfies the relationship of H1 / Di≥0.30.

[0084] With this configuration, when a relatively large moment load is applied and the contact ellipse protrudes onto the auxiliary track surface 2i, the generation of edge load can be more reliably suppressed.

[0085] like Figure 3 As shown in FIG. 1 , the radial distance H3 between the imaginary line α3 extending in the axial direction from the starting end position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k (the distance of the height from the groove bottom position 2k to the starting end 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 ball 7 of the outer side ball row 6. That is, the radial distance H3 between the imaginary line α3 extending in the axial direction from the starting end position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k satisfies the relationship of H3 / Do≥0.30.

[0086] With this configuration, when a relatively large moment load is applied and the contact ellipse protrudes onto the auxiliary track surface 2i, the generation of edge load can be more reliably suppressed.

[0087] like Figure 4 As shown in FIG. 1 , the radial distance H5 between the imaginary line β1 extending in the axial direction from the starting end position 3is of the auxiliary raceway surface 3i and the groove bottom position 3k (the distance of the height from the groove bottom position 3k to the starting end 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 ball 7 of the outer side ball row 6. That is, the radial distance H5 between the imaginary line β1 extending in the axial direction from the starting end position 3is of the auxiliary raceway surface 3i and the groove bottom position 3k satisfies the relationship of H5 / Do≥0.30.

[0088] With this configuration, when a relatively large moment load is applied and the contact ellipse protrudes onto the auxiliary track surface 3i, the generation of edge load can be more reliably suppressed.

[0089] like Figure 5As shown in FIG. 1 , the radial distance H7 between the imaginary line β3 extending in the axial direction from the starting end position 4is of the auxiliary raceway surface 4i and the groove bottom position 4k (the distance of the height from the groove bottom position 4k to the starting end 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 in the axial direction from the starting end position 4is of the auxiliary raceway surface 4i and the groove bottom position 4k satisfies the relationship of H7 / Di≥0.30.

[0090] With this configuration, when a relatively large moment load is applied and the contact ellipse protrudes onto the auxiliary track surface 4i, the generation of edge load can be more reliably suppressed.

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

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

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

[0094] like Figure 2 As shown in FIG. 1 , the radial distance H1 between the imaginary line α1 extending in the axial direction from the starting end position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k is configured to be less than 45% 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 in the axial direction from the starting end position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k satisfies the relationship of H1 / Di≤0.45.

[0095] By configuring in this way, it is possible to suppress an increase in the time required for grinding the auxiliary raceway surface 2i, and to more reliably improve the grindability of the auxiliary raceway surface 2i.

[0096] like Figure 3 As shown in FIG. 1 , the radial distance H3 between the imaginary line α3 extending in the axial direction from the starting end position 2is of the auxiliary raceway surface 2i and the groove bottom position 2k is configured to be less than 45% of the diameter Do of the ball 7 of the outer ball row 6. That is, the radial distance H3 between the imaginary line α3 extending in the axial direction from the starting end 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 time required for grinding the auxiliary raceway surface 2i, and to more reliably improve the grindability of the auxiliary raceway surface 2i.

[0098] like Figure 4 As shown in FIG. 1 , the radial distance H5 between the imaginary line β1 extending in the axial direction from the starting position 3is of the auxiliary raceway surface 3i and the groove bottom position 3k is configured to be less than 45% of the diameter Do of the ball 7 of the outer ball row 6. That is, the radial distance H5 between the imaginary line β1 extending in the axial direction from the starting 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 time required for grinding the auxiliary raceway surface 3i, and to more reliably improve the grindability of the auxiliary raceway surface 3i.

[0100] like Figure 5 As shown in FIG. 1 , the radial distance H7 between the imaginary line β3 extending in the axial direction from the starting end position 4is of the auxiliary raceway surface 4i and the groove bottom position 4k is configured to be less than 45% 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 in the axial direction from the starting end 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 time required for grinding the auxiliary raceway surface 4i, and to more reliably improve the grinding performance of the auxiliary raceway surface 4i.

[0102] like Figure 2 As shown in FIG. 1 , the radial distance H2 between the imaginary line α2 extending in the axial direction from the terminal position 2ie of the auxiliary raceway surface 2i and the groove bottom position 2k (the distance of the height from the groove bottom position 2k to the terminal position 2ie of the auxiliary raceway surface 2i in the radial direction) is configured to be less than 50% of the diameter Di of the ball 7 of the inner side ball row 5. That is, the radial distance H2 between the imaginary line α2 extending in the axial direction from the terminal 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 time required for grinding the auxiliary raceway surface 2i, and to more reliably improve the grindability of the auxiliary raceway surface 4i.

[0104] like Figure 3 As shown in FIG. 1 , the radial distance H4 between the imaginary line α4 extending in the axial direction from the terminal position 2ie of the auxiliary raceway surface 2i and the groove bottom position 2k (the distance of the height from the groove bottom position 2k to the terminal position 2ie of the auxiliary raceway surface 2i in the radial direction) is configured to be less than 50% of the diameter Do of the ball 7 of the outer side ball row 6. That is, the radial distance H4 between the imaginary line α4 extending in the axial direction from the terminal position 2ie of the auxiliary raceway surface 2i and the groove bottom position 2k satisfies the relationship of H4 / Do≤0.50.

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

[0106] like Figure 4 As shown in FIG. 1 , the radial distance H6 between the imaginary line β2 extending in the axial direction from the terminal position 3ie of the auxiliary raceway surface 3i and the groove bottom position 3k (the distance of the height from the groove bottom position 3k to the terminal position 3ie of the auxiliary raceway surface 3i in the radial direction) is configured to be less than 50% of the diameter Do of the ball 7 of the outer side ball row 6. That is, the radial distance H6 between the imaginary line β2 extending in the axial direction from the terminal position 3ie of the auxiliary raceway surface 3i and the groove bottom position 3k satisfies the relationship of H6 / Do≤0.50.

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

[0108] like Figure 5 As shown in FIG. 1 , the radial distance H8 between the imaginary line β4 extending in the axial direction from the terminal position 4ie of the auxiliary raceway surface 4i and the groove bottom position 4k (the distance of the height from the groove bottom position 4k to the terminal position 4ie of the auxiliary raceway surface 4i in the radial direction) is configured to be less than 50% of the diameter Di of the ball 7 of the inner side ball row 5. That is, the radial distance H8 between the imaginary line β4 extending in the axial direction from the terminal position 4ie of the auxiliary raceway surface 4i and the groove bottom position 4k satisfies the relationship of H8 / Di≤0.50.

[0109] By configuring in this way, it is possible to suppress an increase in the time required for grinding the auxiliary raceway surface 4i, and to more reliably improve the grinding performance of the auxiliary raceway surface 4i.

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

[0111] The auxiliary raceway surfaces 2i, 3i, 4i have an average roughness greater than that of the curved surface 2h. This configuration makes it easier to retain the grease base oil on the auxiliary raceway surfaces 2i, 3i, 4i, and more reliably prevents the occurrence of surface-starting type peeling.

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

[0113] like Figure 6 As shown in the figure, the grinding surfaces 2j and 4j are formed into a tapered shape inclined at an angle close to parallel to the axial direction by grinding the ends of the auxiliary track surfaces 2i and 4i with a grindstone. Similarly, the grinding surface 3j can also be formed into a tapered shape inclined at an angle close to parallel to the axial direction by grinding the ends of the auxiliary track surface 3i with a grindstone. Figure 7 As shown in the figure, the grinding surfaces 2j, 4j can also be configured as a chamfered shape in which the ends of the auxiliary track surfaces 2i, 4i are chamfered by grinding the ends of the auxiliary track surfaces 2i, 4i with a grindstone. In addition, similarly, the grinding surface 3j can also be configured as a chamfered shape in which the ends of the auxiliary track surface 3j are chamfered by grinding the ends of the auxiliary track surface 3j with a grindstone.

[0114] It is also possible to configure either the ground surface 2j of the outer member (outer ring 2) or the ground surfaces 3j and 4j of the inner member (hub outer ring 3 and inner ring 4) into a chamfered shape, and configure the other into a tapered shape. Figure 8 As shown in FIG. 1 , the grinding surface 2j of the outer ring 2 can be configured as a cone, and the grinding surface 4j of the inner ring 4 can be configured as a chamfered shape. In addition, similarly, the grinding surface 2j of the outer ring 2 can be configured as a cone, and the grinding surface 3j of the hub outer ring 3 can be configured as a chamfered shape. Fig. 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 also be configured as a tapered shape. In addition, similarly, the grinding surface 2j of the outer ring 2 can also be configured as a chamfered shape, and the grinding surface 3j of the hub outer ring 3 can also be configured as a tapered shape.

[0115] The embodiments of the present invention have been described above, but the present invention is not limited to such embodiments at all, but is merely illustrative, and can of course be further implemented in various ways within the scope of the present invention 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 recorded in the patent technical solution and all changes within the scope.

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. The wheel bearing device 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 set to 0.07 μm or less, and the average roughness Ra of the auxiliary raceway surface is configured to be 15 times or more and 30 times or less of the average roughness Ra of the curved surface.

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