Wheel support rolling bearings

Abstract

To provide a wheel support rolling bearing which can be reduced in a size.SOLUTION: A wheel support rolling bearing 1 comprises an inner ring 10 fixed to a wheel, an outer ring 40 fixed to a vehicle body, and a plurality of needle-shaped rollers 50 rollingly arranged between the inner ring 10 and the outer ring 40. The inner ring 10 has a first raceway surface 11 which opposes the outer ring 40 in a radial direction, and a second raceway surface 12 and a third raceway surface 13 which oppose the outer ring 40 in an axial direction. The second raceway surface 12 is located inside the outer ring 40 in the axial direction, and the third raceway surface 13 is located outside the outer ring 40 in the axial direction. The plurality of needle-shaped rollers 50 include a plurality of first needle-shaped rollers 51 arranged between the first raceway surface 11 and the outer ring 40, a plurality of second needle-shaped rollers 52 arranged between the second raceway surface 12 and the outer ring 40, and a plurality of third needle-shaped rollers 53 arranged between the third raceway surface 13 and the outer ring 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wheel-supporting rolling bearing. [Background technology]

[0002] For example, Patent Documents 1 and 2 describe wheel-supporting rolling bearings used to rotatably support wheels relative to the vehicle body in an automobile. These wheel-supporting rolling bearings use balls or tapered rollers as rolling elements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-154591 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-261490 Summary of the Invention [Problem to be solved by the invention]

[0004] Wheel-support rolling bearings such as those described above require a large space for the rolling elements, making them difficult to miniaturize. This limits how much they can be made lighter, and makes them difficult to install in small spaces.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a wheel-supporting rolling bearing that can be made smaller. [Means for solving the problem]

[0006] The wheel support rolling bearing of the present invention is a wheel support rolling bearing used to rotatably support a wheel relative to a vehicle body, and comprises an inner ring fixed to the wheel, an outer ring fixed to the vehicle body, and a plurality of needle rollers arranged to be able to roll between the inner ring and the outer ring, the inner ring having a first raceway surface facing the outer ring in the radial direction, and a second raceway surface and a third raceway surface facing the outer ring in the axial direction, the second raceway surface being located on the inside in the axial direction relative to the outer ring, and the third raceway surface being located on the outside in the axial direction relative to the outer ring, and the plurality of needle rollers including a plurality of first needle rollers arranged between the first raceway surface and the outer ring, a plurality of second needle rollers arranged between the second raceway surface and the outer ring, and a plurality of third needle rollers arranged between the third raceway surface and the outer ring.

[0007] In this wheel support rolling bearing, the inner ring has a first raceway surface facing the outer ring in the radial direction, and second and third raceway surfaces facing the outer ring on the inner and outer sides in the axial direction, respectively. First, second, and third needle rollers are arranged between the first, second, and third raceway surfaces and the outer ring, respectively. This allows the first needle rollers to bear radial loads, and the second and third needle rollers to bear axial loads. Furthermore, because the rolling elements are needle rollers, the space required for arranging the rolling elements can be reduced, allowing for miniaturization. This wheel support rolling bearing therefore allows for miniaturization.

[0008] The inner ring may include a first member having the second raceway surface and a second member having the third raceway surface, one of the first member and the second member having a crimped portion, and the first member and the second member being fixed to each other by crimping the crimped portion. In this case, the inner ring is formed by the first member and the second member fixed by crimping, which makes it easier to manufacture the inner ring. Furthermore, fixing by crimping allows the first member and the second member to be firmly joined.

[0009] The first member may have a crimped portion, and the crimped portion formed by crimping the crimped portion may be exposed to the outside in the axial direction. In this case, the crimped portion can be visually confirmed from the outside in the axial direction. This has advantages such as making it easier to detect abnormalities in the crimped portion, easier to know when to replace the member, and easier to perform maintenance.

[0010] The second member may have a crimped portion, and a crimped portion formed by crimping the crimped portion may be exposed to the inside in the axial direction. In this case, the design of the wheel support rolling bearing can be simplified.

[0011] A through hole may be formed in the other of the first member and the second member, and the first member and the second member may be fixed to each other by crimping the crimp portion with the crimp portion inserted into the through hole. In this case, the first member and the second member can be fixed in a mechanically engaged state, which can suppress the occurrence of creep, in which the first member and the second member rotate relative to each other, and can also suppress deformation of the inner ring due to frictional forces between the first member and the second member.

[0012] The crimped portion may be configured with a plurality of portions extending axially and aligned circumferentially. In this case, the first member and the second member can be fixed together more firmly. Also, the crimped portion can be made less likely to crack.

[0013] The second raceway surface and the abutting surface of the first member with the second member may be a ground surface or a lapped surface, in which case the variation in preload applied to the second needle roller can be suppressed.

[0014] The third raceway surface and the abutting surface of the second member that abuts against the first member may be ground surfaces or lapped surfaces, in which case the variation in preload applied to the third needle roller can be suppressed.

[0015] The inner ring may be formed of a plate-like member, which allows for greater freedom in design of the inner ring and allows for reductions in size and weight of the inner ring.

[0016] The inner ring may have a fixing portion with an insertion hole formed therein through which the fixing member is inserted, and the thickness of the fixing portion may be greater than the thickness of the portion of the inner ring other than the fixing portion. In this case, the strength of the fixing portion can be increased.

[0017] The inner ring may be formed with a spline for engagement with the joint portion of the drive shaft, in which case the joint portion of the drive shaft can be engaged with the inner ring.

[0018] The inner ring may further have a fourth raceway surface spaced apart from the first raceway surface, the second raceway surface, and the third raceway surface, and the plurality of needle rollers may further include a plurality of fourth needle rollers arranged between the fourth raceway surface and the outer ring. In this case, it is possible to increase the load that the bearing can withstand while suppressing an increase in the size of the bearing.

[0019] The first member may have a first flange portion formed in an annular plate shape facing the outer ring on the inside in the axial direction, the first flange portion having a second raceway surface, and the second member may have a second flange portion formed in an annular plate shape facing the outer ring on the outside in the axial direction, the second flange portion having a third raceway surface. In this case, the degree of freedom in designing the inner ring can be increased, and the inner ring can be made smaller and lighter.

[0020] The inner ring has a first fixed portion fixed to a wheel, and the outer ring has a second fixed portion fixed to a vehicle body, and where the distance in the axial direction between the axially outer surface of the first fixed portion and the axially inner surface of the second fixed portion is L and the distance in the radial direction between the centers of the first needle rollers is D, D / L may be 2 or more. In this case, the diameter of the bearing can be made larger. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a wheel-supporting rolling bearing that can be made smaller in size. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a cross-sectional view of a rolling bearing according to an embodiment. [Figure 2] FIG. 2 is a perspective view of the rolling bearing as seen from the outside in the axial direction. [Figure 3] FIG. 2 is a perspective view of the rolling bearing as seen from the inside in the axial direction. [Figure 4] FIG. 4 is a cross-sectional view of a first member of the inner ring. [Figure 5] FIG. 4 is a cross-sectional view of a second member of the inner ring. [Figure 6] FIG. [Figure 7] FIG. 4 is a cross-sectional view showing a state before the crimped portion is crimped. [Figure 8] FIG. 10 is a cross-sectional view illustrating a crimping step. [Figure 9] FIG. 2 is a cross-sectional view illustrating a portion where grinding and / or lapping has been performed. [Figure 10] 1 is a cross-sectional view showing a state in which a rolling bearing according to an embodiment is connected to a constant velocity joint. [Figure 11] FIG. 3 is a cross-sectional view of a rolling bearing according to a first modified example. [Figure 12] FIG. 10 is a cross-sectional view of a first member of a first modified example. [Figure 13] FIG. 10 is a plan view of a first member of a first modified example. [Figure 14] FIG. 10 is a cross-sectional view of a second member of the first modified example. [Figure 15] FIG. 10 is a cross-sectional view illustrating a crimping step of the first modified example. [Figure 16] FIG. 10 is a cross-sectional view illustrating a ground portion in a first modified example. [Figure 17] FIG. 10 is a cross-sectional view showing a state in which a rolling bearing according to a first modified example is connected to a constant velocity joint. [Figure 18] FIG. 10 is a cross-sectional view of a rolling bearing according to a second modified example. [Figure 19] FIG. 10 is a cross-sectional view illustrating a crimping step of a second modified example. [Figure 20] FIG. 10 is a cross-sectional view of a rolling bearing according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0024] As shown in Figs. 1 to 6, a rolling bearing (wheel-supporting rolling bearing, hub bearing) 1 includes an inner ring 10, an outer ring 40, and a plurality of needle rollers 50. The rolling bearing 1 is used, for example, in a vehicle such as an automobile, to rotatably support a wheel relative to the vehicle body. The inner ring 10 is fixed to the wheel, and the outer ring 40 is fixed to the vehicle body. The inner ring 10 may be fixed to a driving wheel or a driven wheel. When the inner ring 10 is fixed to a driving wheel, a drive shaft is coupled to the inner ring 10 via, for example, a constant velocity joint (joint portion). An example of this will be described later with reference to Fig. 10. The outer ring 40 is fixed, for example, to a suspension device of the vehicle body.

[0025] In the following description, the direction parallel to the rotation axis AX of the rolling bearing 1 is referred to as the axial direction, the direction around the rotation axis AX as the circumferential direction, and the direction perpendicular to the rotation axis AX as the radial direction. In addition, the side in the axial direction where the wheel is located relative to the vehicle body (the lower side in Fig. 1) is referred to as the outer side, and the side in the axial direction where the vehicle body is located relative to the wheel (the upper side in Fig. 1) is referred to as the inner side.

[0026] The inner ring 10 has a first member (main body member) 20 and a second member (flange member) 30. The first member 20 and the second member 30 are formed from plate-shaped metal members. That is, the first member 20 and the second member 30 are formed by plate molding using a plate material. In this example, the first member 20 and the second member 30 are formed by pressing the plate material.

[0027] The first member 20 has a cylindrical portion 21, a first flange portion 22, and a crimped portion 23. The cylindrical portion 21 is formed in a cylindrical shape with the rotation axis AX as its center line. The cylindrical portion 21 has a bottom portion 21a on the outer side in the axial direction, extending perpendicular to the axial direction. The first flange portion 22 is formed in an annular plate shape, and extends radially outward from the inner edge of the cylindrical portion 21 in the axial direction. The first flange portion 22 extends perpendicular to the axial direction, and faces the outer ring 40 on the inner side in the axial direction.

[0028] The crimped portion 23 extends outward in the axial direction from the center of the bottom 21a of the cylindrical portion 21. In this example, the crimped portion 23 is configured with a plurality of extending portions 23a that extend along the axial direction and are arranged in the circumferential direction. Each extending portion 23a is formed, for example, in the shape of an elongated plate (a rod-like shape with a rectangular cross section). As will be described later, the crimped portion 23 is crimped when the first member 20 and the second member 30 are fixed together. FIG. 1 shows the crimped portion 23 after crimping, and FIG. 4 shows the crimped portion 23 before crimping.

[0029] The second member 30 has a first cylindrical portion 31, a second cylindrical portion 32, a second flange portion 33, and a plurality of (four in this example) fixing portions (first fixing portions) 34. The first cylindrical portion 31 is formed in a substantially cylindrical shape with the rotation axis AX as its center line. The first cylindrical portion 31 has a bottom portion 31a on its inner side in the axial direction that extends perpendicular to the axial direction. An outer axial portion 311 of the first cylindrical portion 31 is formed in a shape that widens radially outward as it extends axially outward. The outer portion 311 has an inner surface 311a that is inclined radially outward as it extends axially outward. The second cylindrical portion 32 is formed in a substantially cylindrical shape with the rotation axis AX as its center line and is disposed so as to surround the first cylindrical portion 31. The first cylindrical portion 31 and the second cylindrical portion 32 are connected to each other on the outer side in the axial direction and are integrated.

[0030] The second flange portion 33 is formed in the shape of an annular plate, and extends radially outward from the axially inner edge of the second cylindrical portion 32. The second flange portion 33 extends perpendicular to the axial direction, and faces the outer ring 40 on the outside in the axial direction.

[0031] The fixing portions 34 extend radially outward from the outer peripheral surface of the second flange portion 33 and protrude radially outward from the second flange portion 33. The four fixing portions 34 are arranged at equal intervals along the circumferential direction. Each fixing portion 34 has an insertion hole 34a that penetrates the fixing portion 34 along the axial direction. A fixing member for fixing the inner ring 10 to the wheel is inserted into the insertion hole 34a. The fixing member is, for example, a bolt. The inner ring 10 is fixed to the wheel by inserting the fixing member into the insertion hole 34a and fastening it to the wheel. The thickness of the fixing portions 34 is thicker than the thickness of the portions of the inner ring 10 other than the fixing portions 34 (in this example, the first cylindrical portion 31, the second cylindrical portion 32, and the second flange portion 33). For example, the thickness of the fixing portions 34 can be increased by clamping the fixing portion 34 between a pair of molds.

[0032] The first member 20 and the second member 30 are fixed to each other by crimping the crimped portion 23 of the first member 20. This fixation will be further described below. A plurality of through holes 31b are formed in the bottom portion 31a of the first cylindrical portion 31 of the second member 30, penetrating the bottom portion 31a along the axial direction (FIG. 6). The plurality of through holes 31b are formed, for example, in the same number as the plurality of extension portions 23a of the crimped portion 23, and are arranged so as to be evenly spaced along the circumferential direction. The plurality of extension portions 23a are inserted into the plurality of through holes 31b, respectively, and the extension portions 23a are crimped, thereby fixing the first member 20 and the second member 30 to each other. FIG. 7 shows the state before crimping, and FIG. 1 shows the state after crimping.

[0033] 1, the crimping process bends the middle portion of the extending portion 23a, and the tip portion of the extending portion 23a is deformed to fit along the inner surface 311a of the outer portion 311 of the first cylindrical portion 31. In this way, "crimping the crimping portion 23" means bending and deforming the crimping portion 23 to secure the members, and in this example, the crimping portion 23 is deformed so that the first member 20 and the second member 30 are secured to each other. In this example, the crimped portion 23b (the tip portion of the extending portion 23a) formed by crimping the crimping portion 23 is exposed to the outside in the axial direction. In other words, the crimped portion 23b is visible when viewed from the outside in the axial direction.

[0034] 8, in the crimping process, the tip side portion of crimped portion 23 is crimped by a roller R. In this example, crimped portion 23 is crimped by spin crimping using a roller R whose center line Ra is inclined with respect to the axial direction.

[0035] The outer ring 40 is formed, for example, in a ring shape from a metal material. The outer ring 40 is arranged to surround the cylindrical portion 21 of the first member 20 of the inner ring 10. The outer ring 40 faces the first flange portion 22 of the first member 20 on the inside in the axial direction, and faces the second flange portion 33 of the second member 30 of the inner ring 10 on the outside in the axial direction. The outer peripheral surface of the outer ring 40 is formed with a plurality of (four in this example) fixing portions (second fixing portions) 47 for fixing to the vehicle body. The fixing portions 47 extend radially outward from the outer peripheral surface of the outer ring 40. The fixing portions 47 are formed with insertion holes 47a, and fixing members (e.g., bolts) for fixing to the vehicle body are inserted into the insertion holes 47a. The outer ring 40 is formed, for example, by forging and cutting, but may also be formed by plate forming.

[0036] As shown in FIG. 2 and other figures, the multiple needle rollers 50 include multiple first needle rollers 51, multiple second needle rollers 52, and multiple third needle rollers 53. The needle rollers 50 and their raceway surfaces will be described below. The needle rollers 50 are rollers formed in a needle shape. In this specification, "needle-shaped" refers to a shape in which the length-to-diameter ratio is 3 to 10, or a diameter is 5 mm or less. The multiple first needle rollers 51 have the same shape, the multiple second needle rollers 52 have the same shape, and the multiple third needle rollers 53 have the same shape. The shapes of the first needle rollers 51 and the second needle rollers 52 may be the same or different. Similarly, the shapes of the first needle rollers 51 and the third needle rollers 53 may be the same or different. Similarly, the shapes of the second needle rollers 52 and the third needle rollers 53 may be the same or different.

[0037] The inner ring 10 has a first raceway surface 11, a second raceway surface 12, and a third raceway surface 13 as raceway surfaces along which the first needle rollers 51, the second needle rollers 52, and the third needle rollers 53 roll. The first raceway surface 11 is formed by the outer peripheral surface of the cylindrical portion 21 of the first member 20 and faces the inner peripheral surface of the outer ring 40 in the radial direction. The second raceway surface 12 is formed by the inner surface (the outer surface in the axial direction) of the first flange portion 22 of the first member 20. The third raceway surface 13 is formed by the inner surface (the inner surface in the axial direction) of the second flange portion 33 of the second member 30. The second raceway surface 12 and the third raceway surface 13 face the outer ring 40 in the axial direction. More specifically, the second raceway surface 12 is located on the inner side of the outer ring 40 in the axial direction and faces the inner surface of the outer ring 40 in the axial direction. The third raceway surface 13 is located axially outward relative to the outer ring 40 and faces the axially outer surface of the outer ring 40. In this example, the first raceway surface 11 is a cylindrical surface, and the second raceway surface 12 and the third raceway surface 13 are annular surfaces.

[0038] The outer ring 40 has raceway surfaces 41, 42, and 43 at positions corresponding to the first raceway surface 11, the second raceway surface 12, and the third raceway surface 13. The raceway surface 41 is formed by the bottom surface of a recess 40a formed on the inner peripheral surface of the outer ring 40. The raceway surface 42 is formed by the bottom surface of a recess 40b formed on the inner surface of the outer ring 40 in the axial direction. The raceway surface 43 is formed by the bottom surface of a recess 40c formed on the outer surface of the outer ring 40 in the axial direction. In this example, the raceway surface 41 is a cylindrical surface, and the raceway surfaces 42 and 43 are annular surfaces.

[0039] The multiple first needle rollers 51 are arranged between the first raceway surface 11 of the inner ring 10 and the raceway surface 41 of the outer ring 40, and roll on the first raceway surface 11 and the raceway surface 41. The multiple second needle rollers 52 are arranged between the second raceway surface 12 of the inner ring 10 and the raceway surface 42 of the outer ring 40, and roll on the second raceway surface 12 and the raceway surface 42. The multiple third needle rollers 53 are arranged between the third raceway surface 13 of the inner ring 10 and the raceway surface 43 of the outer ring 40, and roll on the third raceway surface 13 and the raceway surface 43. Although not shown, the multiple first needle rollers 51 are held by a cage so that they can rotate at regular intervals between their raceway surfaces. Similarly, the multiple second needle rollers 52 and the multiple third needle rollers 53 are each held by a separate cage so that they can rotate at regular intervals between their raceway surfaces.

[0040] As shown in Fig. 1, ring-shaped seal portions SL are provided on the axial inner and outer surfaces of the outer ring 40 to seal between it and the inner ring 10. One seal portion SL contacts the inner surface of the first flange portion 22 of the first member 20, and the other seal portion SL contacts the inner surface of the second flange portion 33 of the second member 30. This prevents leakage of the lubricant filled inside the rolling bearing 1 and the intrusion of water and foreign matter from the outside. Note that the seal portions SL are omitted from illustrations other than Fig. 1.

[0041] In this embodiment, the first raceway surface 11, the second raceway surface 12, and the abutment surface of the first member 20 with the second member 30 are ground with a grindstone to form ground surfaces. In FIG. 9 , the areas where these grinding processes have been performed are indicated by solid arrows. Furthermore, the first raceway surface 11 and the second raceway surface 12 are further subjected to lapping, so that the first raceway surface 11 and the second raceway surface 12 form lapped surfaces. The abutment surface of the first member 20 with the second member 30 is the surface with which the first member 20 abuts against the second member 30 when the extended portion 23a of the crimped portion 23 is inserted into the through hole 31b before crimping the crimped portion 23. In this example, it is the outer surface in the axial direction of the bottom 21a of the cylindrical portion 21 of the first member 20. During grinding, the first raceway surface 11, the second raceway surface 12, and the abutment surface of the first member 20 with the second member 30 are ground with the same grindstone. Thereafter, the first raceway surface 11 and the second raceway surface 12 are subjected to lapping. This reduces the difference in height between these surfaces. As a result, the difference in size between the surfaces can be reduced, and the variation in the preload applied to the first needle rollers 51 and the second needle rollers 52 can be suppressed.

[0042] The third raceway surface 13 and the abutment surface of the second member 30 that abuts against the first member 20 are ground with a grindstone to form ground surfaces. In FIG. 9 , the areas where these grinding processes have been performed are indicated by dashed-dotted arrows. The third raceway surface 13 is also subjected to lapping, forming a lapped surface. The abutment surface of the second member 30 that abuts against the first member 20 is the surface that the second member 30 abuts against the first member 20 when the extended portion 23a of the crimped portion 23 is inserted into the through hole 31b before the crimped portion 23 is crimped. In this example, this is the axially inner surface of the bottom 31a of the first cylindrical portion 31 of the second member 30. During grinding, the third raceway surface 13 and the abutment surface of the second member 30 that abuts against the first member 20 are ground with the same grindstone. Then, the third raceway surface 13 is subjected to lapping. This reduces the difference in height between these surfaces. As a result, the difference in dimension between the surfaces can be reduced, and the variation in the preload applied to the third needle rollers 53 can be suppressed. When adjusting the preload, for example, the dimensions of the ground surfaces and the outer ring 40 can be measured, and the first needle rollers 51, second needle rollers 52, and third needle rollers 53, which have been classified according to diameter, can be combined based on the measurement results, thereby adjusting the preload. Note that while Figure 9 shows the areas on the left side of the rotation axis AX that have been ground and / or lapped, the right side of the rotation axis AX has also been ground and / or lapped in the same way.

[0043] As shown in Fig. 10, when the inner ring 10 is fixed to a drive wheel, a constant velocity joint 60 may be attached to the inner ring 10. Although not shown, splines for engaging the inner ring 10 with the constant velocity joint 60 are formed on the contact surface of the inner ring 10 with the constant velocity joint 60 and on the contact surface of the constant velocity joint 60 with the inner ring 10. These splines are fitted together and coupled together, thereby engaging the inner ring 10 with the constant velocity joint 60. In this example, splines are formed on the inner circumferential surface of the cylindrical portion 21 of the first member 20 and on the outer surface (the inner surface in the axial direction) of the first flange portion 22. [Action and effect]

[0044] In the rolling bearing 1, the inner ring 10 has a first raceway surface 11 that faces the outer ring 40 in the radial direction, and a second raceway surface 12 and a third raceway surface 13 that face the outer ring 40 on the inner and outer sides, respectively, in the axial direction. A first needle roller 51, a second needle roller 52, and a third needle roller 53 are disposed between the first raceway surface 11, the second raceway surface 12, and the third raceway surface 13 and the outer ring 40, respectively. This allows the first needle roller 51 to bear radial loads, and the second needle roller 52 and the third needle roller 53 to bear axial loads. Furthermore, because these rolling elements are needle rollers, the space required for arranging the rolling elements can be reduced, allowing for miniaturization. Therefore, the rolling bearing 1 allows for miniaturization. Such a compact rolling bearing 1 can be particularly effectively used in, for example, electric vehicles. This is because weight reduction is important in electric vehicles, and various structures can be adopted, so bearings suitable for these structures are likely to be required.

[0045] The first member 20 has a crimped portion 23, and the first member 20 and the second member 30 are fixed to one another by crimping the crimped portion 23. This allows the inner ring 10 to be configured by the first member 20 and the second member 30 fixed by crimping, making it possible to easily manufacture the inner ring 10. Furthermore, by fixing them by crimping, the first member 20 and the second member 30 can be firmly joined together.

[0046] The crimped portion 23b formed by crimping the crimped portion 23 is exposed to the outside in the axial direction. This allows the crimped portion 23b to be visually confirmed from the outside in the axial direction. This has the advantages of making it easier to discover abnormalities in the crimped portion 23b, to know when to replace the component, and to perform maintenance, for example.

[0047] A through hole 31b is formed in the second member 30, and the first member 20 and the second member 30 are fixed to each other by inserting the crimping portion 23 into the through hole 31b and crimping the crimping portion 23. This allows the first member 20 and the second member 30 to be fixed in a mechanically engaged state, suppressing the occurrence of creep, which causes relative rotation between the first member 20 and the second member 30, and suppressing deformation of the inner ring 10 due to friction between the first member 20 and the second member 30. That is, in conventional configurations using balls or tapered rollers as rolling elements, creep countermeasures are usually implemented using two types of friction. The first type is axial friction. To increase the axial friction, it is necessary to increase the force (axial force) that clamps the inner ring by crimping. The other type is radial friction. To increase the radial friction, it is necessary to increase the interference fit. However, increasing these two frictional forces can cause problems such as deformation of the inner ring, cracking, or expansion of the inner ring. In contrast, in the rolling bearing 1 of this embodiment, the inner ring 10 is formed by plate molding, allowing a hole of any shape to be drilled using a press. By inserting the crimped portion 23 into the through hole 31b, the crimped portion 23 is mechanically caught in the through hole 31b, thereby suppressing the occurrence of creep. Furthermore, because there is no need to increase the frictional forces, a small axial force is sufficient, and the fit is also small. As a result, the inner ring is hardly deformed, and is less likely to expand.

[0048] The crimped portion 23 is configured with a plurality of extending portions 23a that extend along the axial direction and are arranged in the circumferential direction, thereby enabling the first member 20 and the second member 30 to be fixed together more firmly. In addition, the crimped portion 23 can be made less likely to crack.

[0049] The second raceway surface 12 is a lapped surface, and the abutting surface of the first member 20 with the second member 30 (the axially outer surface of the bottom 21a of the cylindrical portion 21) is a ground surface. This makes it possible to suppress variations in the preload applied to the second needle rollers 52.

[0050] The third raceway surface 13 is a lapped surface, and the abutting surface of the second member 30 with the first member 20 (the inner surface in the axial direction of the bottom 31a of the first cylindrical portion 31) is a ground surface. This makes it possible to suppress variations in the preload applied to the third needle rollers 53.

[0051] The inner ring 10 is formed solely from plate-shaped members. This allows for greater freedom in design of the inner ring 10, and also enables the inner ring 10 to be made smaller and lighter. Furthermore, for example, when forming an inner ring by hot forging, problems such as high press loads, large equipment size, and large amounts of carbon dioxide emissions arise, whereas the rolling bearing 1 according to the embodiment requires low press loads, small equipment, and is cold-formed, resulting in small carbon dioxide emissions, and thus can solve the above problems.

[0052] The inner ring 10 has a fixing portion 34 formed with an insertion hole 34a through which a fixing member is inserted, and the thickness of the fixing portion 34 is greater than the thickness of the portion of the inner ring 10 other than the fixing portion 34. This increases the strength of the fixing portion 34.

[0053] The inner ring 10 is formed with splines for engagement with a constant velocity joint 60 (joint portion of a drive shaft). This allows the constant velocity joint 60 to engage with the inner ring 10.

[0054] The first member 20 has a first flange portion 22 formed in the shape of an annular plate and facing the outer ring 40 on the inside in the axial direction, the first flange portion 22 having a second raceway surface 12, and the second member 30 has a second flange portion 33 formed in the shape of an annular plate and facing the outer ring 40 on the outside in the axial direction, the second flange portion 33 having a third raceway surface 13. This increases the degree of freedom in designing the inner ring 10, making it possible to accommodate strict bending moment requirements, and also enabling the inner ring 10 to be made smaller and lighter. [Variations]

[0055] 11 to 17 show a rolling bearing 1A of a first modified example. In the first modified example, a first member 20 has a cylindrical portion 21 and a first flange portion 22, but does not have a crimped portion 23. A plurality of through holes 21b are formed in a bottom portion 21a of the cylindrical portion 21, through which crimped portions 35, which will be described later, are inserted. The plurality of through holes 21b penetrate the bottom portion 21a along the axial direction, and are arranged so as to be evenly spaced apart along the circumferential direction.

[0056] In the first modified example, the first cylindrical portion 31 of the second member 30 does not have a bottom portion 31a, but has a crimped portion 35. The crimped portion 35 extends inward in the axial direction from the inner edge of the first cylindrical portion 31. The crimped portion 35 is made up of a plurality of extending portions 35a that extend along the axial direction and are arranged in the circumferential direction. Each extending portion 35a is formed, for example, in the shape of an elongated plate (a rod shape with a rectangular cross section).

[0057] In the first modified example, the first member 20 and the second member 30 are fixed to each other by crimping each of the extending portions 35a of the crimping portion 35 while the extending portions 35a are inserted into the respective through holes 21b. In the first modified example, the direction in which the crimping portion 35 is inserted into the through holes 21b is opposite to the direction in which the crimping portion 23 is inserted into the through holes 31b in the above embodiment. Fig. 14 shows the crimping portion 23 before crimping, and Fig. 11 shows the state after crimping.

[0058] 11, the crimping process bends the extending portion 35a at its middle portion, and the tip end portion of the extending portion 35a is deformed to fit along the outer surface (the inner surface in the axial direction) of the first flange portion 22 of the cylindrical portion 21 of the first member 20. The crimped portion 35b (the tip end portion of the extending portion 35a) formed by crimping the crimped portion 35 is exposed to the inside in the axial direction. In this case, for example, an ABS sensor can be attached by utilizing the fact that the crimped portion 35 is divided at equal intervals.

[0059] As shown in Figure 15, in the crimping process, rollers R1 and R2 crimp the tip side portion of crimped portion 35. In this example, crimped portion 35 is crimped by rollers R1 and R2, which are arranged so that center lines R1a and R2a are parallel to the radial direction. Rollers R1 and R2 are arranged symmetrically at equal intervals along the radial direction. This allows a load to be applied evenly to crimped portion 35. The reason for applying the load evenly is to prevent deformation of inner ring 10 due to uneven load during crimping.

[0060] In the first modified example, the first raceway surface 11, the second raceway surface 12, and the abutment surface of the first member 20 with the second member 30 are also ground with a grindstone to form ground surfaces. In Fig. 16, the areas where these grinding processes have been performed are indicated by solid arrows. Furthermore, the first raceway surface 11 and the second raceway surface 12 are further subjected to lapping, so that the first raceway surface 11 and the second raceway surface 12 form lapped surfaces. The abutment surface of the first member 20 with the second member 30 is the surface that the first member 20 abuts against the second member 30 when the extension portion 35a of the crimping portion 35 is inserted into the through hole 21b before the crimping of the crimping portion 35; in this example, it is the outer surface in the axial direction of the bottom portion 21a of the cylindrical portion 21 of the first member 20.

[0061] The third raceway surface 13 and the abutment surface of the second member 30 that abuts against the first member 20 are ground with a grindstone to form ground surfaces. In FIG. 16, the grinding processes are indicated by the two-dot chain arrows. The third raceway surface 13 is also lapped to form a lapped surface. The abutment surface of the second member 30 that abuts against the first member 20 is the surface against which the second member 30 abuts against the first member 20 when the extension portion 35a of the crimping portion 35 is inserted into the through hole 21b before the crimping of the crimping portion 35. In this example, this is a stepped surface (not shown) formed on the first cylindrical portion 31 of the second member 30. Note that while FIG. 16 shows the areas on the left side of the rotation axis AX that have been ground and / or lapped, the right side of the rotation axis AX is also ground and / or lapped in the same manner.

[0062] 17, a constant velocity joint 60 may also be attached to the inner ring 10 in the first modified example. In this example, splines are formed on the surface of the crimped portion 35 (the crimped portion 35b and the portion of the extended portion 35a other than the crimped portion 35b) of the second member 30. The splines formed on the surface of the crimped portion 35b are face splines that take advantage of the fact that the crimped portion 35 is divided into equal intervals.

[0063] As with the above embodiment, the rolling bearing 1A of the first modified example can also be made smaller. Furthermore, the second member 30 has a crimped portion 35, and a crimped portion 35b formed by crimping the crimped portion 35 is exposed to the inside in the axial direction. This makes it possible to simplify the design of the rolling bearing 1.

[0064] 18 and 19 show a rolling bearing 1B of a second modified example. In the second modified example, the inner diameters of the inner ring 10 and the outer ring 40 are larger than those of the above embodiment. If the distance in the axial direction between the surface 34b of the fixed portion 34 of the inner ring 10 and the surface 47b of the fixed portion 47 of the outer ring 40 is L, and the distance in the radial direction between the center lines of the first needle rollers 51 is D, then D / L is 2 or more. The surface 34b is the outer surface of the fixed portion 34 in the axial direction, and the surface 47b is the inner surface of the fixed portion 47 in the axial direction. The distance D is the distance between the center lines of a pair of first needle rollers 51 facing each other in the radial direction.

[0065] The rolling bearing 1B of the second modified example also allows for miniaturization, as in the above embodiment. Furthermore, since the D / L ratio is 2 or greater, the diameter of the rolling bearing 1B can be increased. Thus, since the inner ring 10 is formed by plate forming, the diameter of the inner ring 10 can be increased. That is, in conventional configurations using balls or tapered rollers as rolling elements, hot forging is often performed using large equipment capable of applying loads of several thousand tons. Therefore, due to the limitations of the equipment, it is difficult to manufacture a large-diameter wheel-support rolling bearing. In contrast, with the rolling bearing 1B of the second modified example, the inner ring 10 is formed by plate forming, so only processes such as bending and drawing are performed, and the large load required in forging is not required. Therefore, the diameter of the wheel-support rolling bearing can be increased. This configuration is particularly effective when, for example, a gear or the like is incorporated into the bearing, such as in an in-wheel motor.

[0066] 19, in the crimping step of the second modified example, rollers R3 and R4 crimp the tip side portion of crimp portion 35. For example, in this example, crimp portion 35 is crimped by spin crimping using rollers R3 and R4 whose center lines R3a and R4a are inclined relative to the axial direction. Forming inner ring 10 by plate molding results in an extremely small crimping load, which also reduces carbon dioxide emissions and enables crimping using extremely small, inexpensive equipment.

[0067] FIG. 20 shows a rolling bearing 1C of a third modified example. The third modified example differs from the second modified example in that the plurality of needle rollers 50 further includes a plurality of fourth needle rollers 54, a plurality of fifth needle rollers 55, and a plurality of sixth needle rollers 56. In the third modified example, the outer ring 40 has a portion 40g located outside the second cylindrical portion 32 of the second member 30, and raceway surfaces 44, 45, and 46 are formed on the portion 40g. The raceway surface 44 is formed by the bottom surface of a recess formed on the radially inner surface of the portion 40g. The raceway surface 45 is formed by the bottom surface of a recess formed on the axially outer surface of the portion 40g. The raceway surface 46 is formed by the bottom surface of a recess formed on the radially outer surface of the portion 40g.

[0068] The inner ring 10 further has a fourth raceway surface 14, a fifth raceway surface 15, and a sixth raceway surface 16. The fourth raceway surface 14 is formed by the outer peripheral surface of the first cylindrical portion 31 of the second member 30, and faces raceway surface 44 in the radial direction. The fifth raceway surface 15 is formed by the inner surface (the inner surface in the axial direction) of the connecting portion between the first cylindrical portion 31 and the second cylindrical portion 32 of the second member 30, and faces raceway surface 45 in the axial direction. The sixth raceway surface 16 is formed by the inner peripheral surface of the second cylindrical portion 32 of the second member 30, and faces raceway surface 46 in the radial direction.

[0069] The plurality of fourth needle rollers 54 are arranged between the fourth raceway surface 14 of the inner ring 10 and the raceway surface 44 of the outer ring 40, and roll on the fourth raceway surface 14 and the raceway surface 44. The plurality of fifth needle rollers 55 are arranged between the fifth raceway surface 15 of the inner ring 10 and the raceway surface 45 of the outer ring 40, and roll on the fifth raceway surface 15 and the raceway surface 45. The plurality of sixth needle rollers 56 are arranged between the sixth raceway surface 16 of the inner ring 10 and the raceway surface 46 of the outer ring 40, and roll on the sixth raceway surface 16 and the raceway surface 46.

[0070] The rolling bearing 1C of the third modified example also achieves miniaturization, as in the above embodiment. Furthermore, the multiple needle rollers 50 include multiple fourth needle rollers 54 arranged between the fourth raceway surface 14 and the outer ring 40. This increases the load that the rolling bearing 1C can withstand while minimizing the increase in size. Furthermore, compared to the second modified example, for example, the number of rolling elements can be increased with little change in size, enabling strength design tailored to requirements. For example, even if a force (bending moment) that spreads the fixed portions 34, 47 (flanges) acts as shown by the arrows in FIG. 20 , the force can be absorbed by the fourth needle rollers 54, fifth needle rollers 55, and sixth needle rollers 56, thereby increasing strength.

[0071] The present invention is not limited to the above-described embodiments and modifications. For example, the materials and shapes of each component are not limited to those described above, and various materials and shapes can be used. The inner ring 10 may be composed of only one member. The inner ring 10 (first member 20 and second member 30) may be formed from a material other than a plate-shaped member. A portion of the inner ring 10 may be formed from a material other than a plate-shaped member, or the entire inner ring 10 may be formed from a material other than a plate-shaped member.

[0072] The first member 20 and the second member 30 may be fixed to each other by a fixing method other than crimping. The crimped portion 23 does not have to have multiple extending portions 23a and may be composed of, for example, a single crimp piece. In the above embodiment, the crimped portion 23 is crimped while inserted into the through hole 31b. However, the first member 20 and the second member 30 may be fixed to each other by crimping the crimped portion 23 that is not inserted into the through hole without inserting the crimped portion 23 into the through hole. The first raceway surface 11, the second raceway surface 12, and the abutting surface of the first member 20 that abuts against the second member 30 do not have to be ground surfaces. Similarly, the third raceway surface 13, and the abutting surface of the second member 30 that abuts against the first member 20 do not have to be ground surfaces. The thickness of the fixing portion 34 may be equal to the thickness of the inner ring 10 other than the fixing portion 34. [Explanation of symbols]

[0073] 1, 1A, 1B, 1C... rolling bearing (wheel support rolling bearing), 10... inner ring, 11... first raceway surface, 12... second raceway surface, 13... third raceway surface, 14... fourth raceway surface, 20... first member, 21b... through hole, 22... first flange portion, 23... crimped portion, 23a... extension portion, 23b... crimped portion, 30... second member, 31b... through hole, 33...second flange portion, 34...fixed portion (first fixed portion), 34a...insertion hole, 34b...surface, 35...crimped portion, 35a...extension portion, 35b...crimped portion, 40...outer ring, 47...fixed portion (second fixed portion), 47b...surface, 50...needle roller, 51...first needle roller, 52...second needle roller, 53...third needle roller, 54...fourth needle roller.

Claims

1. A wheel-supporting rolling bearing used to rotatably support a wheel relative to a vehicle body, an inner ring fixed to the wheel; an outer ring fixed to the vehicle body; a plurality of needle rollers rollably arranged between the inner ring and the outer ring, the plurality of needle rollers having a length to diameter ratio of 3 or more and 10 or less, the inner ring has a first raceway surface facing the outer ring in a radial direction, and a second raceway surface and a third raceway surface facing the outer ring in an axial direction, the second raceway surface being located inside the outer ring in the axial direction, and the third raceway surface being located outside the outer ring in the axial direction, the plurality of needle rollers include a plurality of first needle rollers arranged between the first raceway surface and the outer ring, a plurality of second needle rollers arranged between the second raceway surface and the outer ring, and a plurality of third needle rollers arranged between the third raceway surface and the outer ring.

2. the inner ring includes a first member having the second raceway surface and a second member having the third raceway surface, one of the first member and the second member has a crimped portion, 2. The wheel-supporting rolling bearing according to claim 1, wherein the first member and the second member are fixed to each other by crimping the crimped portion.

3. the first member has the crimped portion, 3. The wheel-supporting rolling bearing according to claim 2, wherein a crimped portion formed by crimping the crimped portion is exposed to the outside in the axial direction.

4. the second member has the crimped portion, 3. The wheel-supporting rolling bearing according to claim 2, wherein a crimped portion formed by crimping the crimped portion is exposed to an inner side in the axial direction.

5. a through hole is formed in the other of the first member and the second member, 5. The wheel support rolling bearing according to claim 2, wherein the first member and the second member are fixed to each other by crimping the crimp portion with the crimp portion inserted into the through hole.

6. The wheel support rolling bearing according to any one of claims 2 to 5, wherein the crimped portion is constituted by a plurality of portions formed so as to extend along the axial direction and to be aligned along the circumferential direction.

7. 7. The wheel support rolling bearing according to claim 2, wherein the second raceway surface and the abutting surface of the first member that abuts against the second member are ground surfaces that have been subjected to grinding processing or lapped surfaces that have been subjected to lapping processing.

8. The wheel support rolling bearing according to any one of claims 2 to 7, wherein the third raceway surface and the abutting surface of the second member that abuts against the first member are ground surfaces that have been subjected to grinding processing or lapped surfaces that have been subjected to lapping processing.

9. A wheel supporting rolling bearing used to rotatably support a wheel relative to a vehicle body, comprising: an inner ring fixed to the wheel; an outer ring fixed to the vehicle body; a plurality of needle rollers rollably disposed between the inner ring and the outer ring, the inner ring has a first raceway surface facing the outer ring in a radial direction, and a second raceway surface and a third raceway surface facing the outer ring in an axial direction, the second raceway surface being located inside the outer ring in the axial direction, and the third raceway surface being located outside the outer ring in the axial direction, the plurality of needle rollers include a plurality of first needle rollers arranged between the first raceway surface and the outer ring, a plurality of second needle rollers arranged between the second raceway surface and the outer ring, and a plurality of third needle rollers arranged between the third raceway surface and the outer ring, The wheel-supporting rolling bearing, wherein the inner ring is formed of a plate-shaped member.

10. the inner ring has a fixing portion formed with an insertion hole through which a fixing member is inserted, 10. The wheel supporting rolling bearing according to claim 9, wherein the thickness of the fixed portion is greater than the thickness of the portion of the inner ring other than the fixed portion.

11. 11. A wheel-supporting rolling bearing according to claim 1, wherein the inner ring is formed with a spline for engagement with a joint portion of a drive shaft.

12. A wheel-supporting rolling bearing used to rotatably support a wheel relative to a vehicle body, comprising: an inner ring fixed to the wheel; an outer ring fixed to the vehicle body; a plurality of needle rollers rollably disposed between the inner ring and the outer ring, the inner ring has a first raceway surface facing the outer ring in a radial direction, and a second raceway surface and a third raceway surface facing the outer ring in an axial direction, the second raceway surface being located inside the outer ring in the axial direction, and the third raceway surface being located outside the outer ring in the axial direction, the plurality of needle rollers include a plurality of first needle rollers arranged between the first raceway surface and the outer ring, a plurality of second needle rollers arranged between the second raceway surface and the outer ring, and a plurality of third needle rollers arranged between the third raceway surface and the outer ring, the inner ring further has a fourth raceway surface spaced apart from the first raceway surface, the second raceway surface, and the third raceway surface, the plurality of needle rollers further include a plurality of fourth needle rollers arranged between the fourth raceway surface and the outer ring.

13. the first member has a first flange portion formed in an annular plate shape and facing the outer ring on an inner side in the axial direction, the first flange portion having the second raceway surface, 9. A wheel support rolling bearing according to claim 2, wherein the second member has a second flange portion formed in an annular plate shape and facing the outer ring on the outside in the axial direction, and the second flange portion has the third raceway surface.

14. the inner ring has a first fixing portion fixed to the wheel; the outer ring has a second fixing portion fixed to the vehicle body, 14. A wheel support rolling bearing according to claim 1, wherein, where L is a distance in the axial direction between an outer surface of the first fixed portion and an inner surface of the second fixed portion in the axial direction, and D is a distance between center lines of the first needle rollers in the radial direction, D / L is 2 or greater.

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