Wheel rolling bearing device

Abstract

To provide a wheel rolling bearing device for, if a flange part to which a wheel is mounted is elastically deformed, preventing a cylindrical part supporting the wheel from its inner periphery side from being easily influenced thereby while enhancing accuracy of concentricity between the wheel to be mounted to the flange part and a shaft part of a joint.SOLUTION: An inward member 11 of a wheel rolling bearing device 10 having a wheel-mounted flange part 26 is provided with a through-hole 27 passing therethrough in an axial direction. A joint 50 having a cup part 51 contacting the inward member 12 and a shaft part 52 passing through the through-hole 27, and the inward member 12 are integrally rotatable. A fastening member 30 has a female screw part 31 to be threaded to a male screw part 56 provided on one axial side of the shaft part 52. The fastening member 30 has a contact face 32 for contacting the inward member 12 from one axial direction with the female screw part 31 threaded to the male screw part 56, and a cylindrical face 33 having a cylindrical outer peripheral face 34 protruded to one axial side further than the flange part 26 and coaxial with a center line L of the female screw part 31.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rolling bearing device for a wheel.

Background Art

[0002] As disclosed in Patent Document 1, in order to transmit the rotational power of a drive shaft to a rolling bearing device 90 for a wheel (see FIG. 3), the drive shaft has a constant velocity joint 96 (hereinafter referred to as "joint 96") that is coupled to a hollow shaft portion (inner member) 91 of the rolling bearing device 90. FIG. 3 shows a part of the joint 96. The hollow shaft portion 91 has a flange portion 94 to which a wheel 99 and a disk rotor (not shown) of a brake device are attached on one axial side (vehicle outer side) thereof.

[0003] The joint 96 has a cup portion 97 that contacts an inner ring 92 of the hollow shaft portion 91 from the other axial side (vehicle inner side), and a shaft portion 98 that penetrates a through hole 91a of the hollow shaft portion 91. A male screw portion 98a is provided at an end portion on one axial side of the shaft portion 98. By screwing and tightening a nut 95 onto the male screw portion 98a, the joint 96 and the hollow shaft portion 91 are integrated.

[0004] Patent Document 2 discloses a rolling bearing device for a wheel provided with a pilot ring. The pilot ring has a portion that protrudes axially from a flange portion of a hub ring (inner member). When attaching a wheel to the flange portion, the pilot ring has a function of supporting the wheel from its inner peripheral side. A fixing nut is used to integrate the hub ring and the joint, and the fixing nut is screwed onto a male screw portion of a shaft portion of the joint. The pilot ring is interposed between the fixing nut and the hub ring, and the fixing nut is tightened onto the male screw portion. Thereby, the hub ring and the joint are integrated, and the pilot ring is fixed to the hub ring.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In the case of the wheel rolling bearing device disclosed in Patent Document 1, as shown in Figure 3, the hollow shaft portion 91 has a cylindrical portion 93 that protrudes from the flange portion 94 to one axial side. When the wheel 99 is attached to the flange portion 94, the cylindrical portion 93 supports the wheel 99 from its inner circumference. The cylindrical portion 93 is integrally formed with the main body 91b and flange portion 94 of the hollow shaft portion 91 by forging or the like. Therefore, when the flange portion 94 elastically deforms due to a force input from, for example, the wheel 99 side during vehicle operation, stress concentration occurs at the base portion 93a of the cylindrical portion 93.

[0007] In the case of the wheel rolling bearing device disclosed in Patent Document 2, the pilot ring is provided as a separate component from the hub ring and is positioned by being fitted onto the hub ring. The pilot ring has a hole that passes through the shaft portion of the coupling. The diameter of the hole is larger than that of the shaft portion. Therefore, the pilot ring is not positioned radially in relation to the shaft portion of the coupling. It is desirable that the accuracy of the coaxiality between the shaft portion of the coupling, which serves as the reference for the rotation center of the wheel and the rolling bearing device for the wheel, and the pilot ring be as high as possible. In the configuration of Patent Document 2, as described above, the pilot ring is not positioned radially in relation to the shaft portion of the coupling. Therefore, there is a possibility that sufficient accuracy of the coaxiality cannot be obtained.

[0008] Therefore, the present disclosure aims to improve the accuracy of coaxiality between the wheel attached to the flange and the shaft of the coupling in a wheel rolling bearing device, so that even if the flange portion to which the wheel is attached undergoes elastic deformation, the cylindrical portion that supports the wheel from its inner circumference is less affected by this deformation. [Means for solving the problem]

[0009] (1) The rolling bearing device for a wheel according to the present disclosure comprises an outer member having an outer raceway surface on its inner circumference, an inner member having an inner raceway surface on its outer circumference, and a plurality of rolling elements provided between the outer raceway surface and the inner raceway surface, The aforementioned inner member has a flange portion for wheel mounting on one axial side and is provided with a through hole that penetrates in the axial direction. A rolling bearing device for a wheel, comprising a joint having a cup portion that contacts the inner member from the other axial side and a shaft portion that passes through the through hole, and the inner member, wherein the joint and the joint are able to rotate as a single unit, The fastening member comprises a female threaded portion that screws into a male threaded portion provided on one axial side of the shaft portion, The fastening member has a contact surface that contacts the inner member from one axial side by screwing the female threaded portion with the male threaded portion, and a cylindrical portion that has a cylindrical outer surface that protrudes from the flange portion to one axial side and is coaxial with the center line of the female threaded portion.

[0010] According to the wheel rolling bearing device of this disclosure, the coupling and the inner member are integrated by screwing the female thread portion of the fastening member into the male thread portion of the coupling. The fastening member is separate from the inner member and has a cylindrical portion that protrudes axially in one direction from the flange portion. Because the fastening member with the cylindrical portion is separate from the inner member, the cylindrical portion is less affected even if the flange portion undergoes elastic deformation.

[0011] The cylindrical section has the function of supporting the wheel, which is attached to the flange section, from its inner circumference. The outer cylindrical surface of the cylindrical section is coaxial with the center line of the female thread section. Therefore, when the female thread section is screwed into the male thread section of the shaft, the degree of coaxiality between the outer cylindrical surface of the cylindrical section and the shaft section is increased. As a result, it is possible to improve the accuracy of the coaxiality between the wheel, which is supported by the cylindrical section and attached to the flange section, and the shaft section.

[0012] (2) Preferably, the inner member has a tapered hole on one axial side that expands in diameter toward the axial side, and the fastening member has a tapered outer surface that contacts the tapered hole as the contact surface. With this configuration, when the female threaded portion of the fastening member is screwed onto the male threaded portion of the joint and tightened, a portion of the force due to the tightening becomes a radial force. In other words, the axial force generated on the shaft is mitigated. As a result, it is possible to reduce the noise generated between the cup portion of the joint and the inner member.

[0013] (3) Preferably, the fastening member has a shape that is recessed from one axial side to the other axial side and has a recess in the center through which the female thread portion opens. This configuration makes it possible to reduce the weight of the fastening member. [Effects of the Invention]

[0014] According to the wheel rolling bearing device of this disclosure, even if the flange portion undergoes elastic deformation, the cylindrical portion is less affected, and it is possible to improve the accuracy of the coaxiality between the wheel attached to the flange portion and the shaft portion of the coupling. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a cross-sectional view showing an example of a rolling bearing device for wheels according to the present invention. [Figure 2] Figure 2 is a cross-sectional view showing the fastening member and its surroundings. [Figure 3] Figure 3 is a cross-sectional view showing a conventional rolling bearing device for wheels. [Modes for carrying out the invention]

[0016] Figure 1 is a cross-sectional view showing an example of a wheel rolling bearing device of the present invention. The wheel rolling bearing device 10 shown in Figure 1 (hereinafter referred to as "bearing device 10") is a wheel bearing device (hub unit) used in automobiles. The bearing device 10 rotatably supports the wheel 7 and the brake disc rotor (not shown) with respect to the suspension system provided on the body of the automobile.

[0017] In order to transmit the rotational power of the drive shaft to the bearing device 10, the drive shaft has a constant velocity universal joint 50 (hereinafter referred to as "joint 50") that is coupled to the bearing device 10 (inner member 12 described later). FIG. 1 shows a part of the joint 50.

[0018] The bearing device 10 includes a cylindrical outer member 11, an inner member 12 having a portion located radially inside thereof, a plurality of balls (rolling elements) 13 provided in two rows between the outer member 11 and the inner member 12, and an annular cage 14 that holds the plurality of balls 13. In the no-load state, the center line of the outer member 11 and the center line of the inner member 12 coincide. These center lines are defined as the center line C of the bearing device 10. FIG. 1 is a cross-sectional view in a plane including the center line C.

[0019] Regarding the bearing device 10 of the present disclosure, definitions are made for each direction. The direction along the center line C of the bearing device 10 is defined as the "axial direction". In this axial direction, the direction parallel to the center line C is also included. In the bearing device 10, the vehicle outer side (the right side in FIG. 1) is defined as one side in the axial direction, and the vehicle inner side (the left side in FIG. 1) on the opposite side is defined as the other side in the axial direction. The direction orthogonal to the center line C is defined as the "radial direction". The direction along a circle centered on the center line C is defined as the "circumferential direction". The direction in which the inner member 12 rotates around the center line C is the "circumferential direction".

[0020] The outer member 11 has a fixed flange portion 21 on its outer periphery that is fixed to a part of the suspension device (not shown). The outer member 11 has a first outer raceway surface 22a and a second outer raceway surface 22b on its inner periphery.

[0021] The inner member 12 has an inner shaft 16 and an inner ring 17 attached to the other axial side of the inner shaft 16. The inner shaft 16 has a shaft body 25 and a flange portion 26 to which a wheel 7 or the like is attached. The flange portion 26 extends radially outward from an end portion 25a on one axial side of the shaft body 25. The inner ring 17 is fixed to a portion 25b on the other axial side of the shaft body 25 with an interference fit.

[0022] The inner shaft 16 has a first inner raceway surface 24a on its outer circumference. The inner ring 17 has a second inner raceway surface 24b on its outer circumference. The inner shaft 16 is provided with a through hole 27 that penetrates axially. The center line of the through hole 27 coincides with the center line C of the bearing device 10. The through hole 27 has a splined hole portion 28 that spline-fits with the shaft portion 52 of the coupling 50, and a non-splined hole portion 29 that does not spline-fit with the shaft portion 52.

[0023] The inner shaft 16 has a tapered hole 19 on one axial side that expands in diameter toward the axial direction. The inner shaft 16 further has a cylindrical hole 20 that is continuous with the axial end of the tapered hole 19. A mounting surface 26a for the flange portion 26 is provided radially outward from the axial end of the cylindrical hole 20. The mounting surface 26a is provided along a plane perpendicular to the center line C. The tapered hole 19 and the cylindrical hole 20 are holes centered on the center line C. The tapered hole 19 connects to a through hole 27 on its other axial side.

[0024] The balls 13 included in the row on one side of the axial direction are located between the first outer raceway surface 22a and the first inner raceway surface 24a, and contact the first outer raceway surface 22a and the first inner raceway surface 24a at a contact angle. The balls 13 included in the row on the other side of the axial direction are located between the second outer raceway surface 22b and the second inner raceway surface 24b, and contact the second outer raceway surface 22b and the second inner raceway surface 24b at a contact angle.

[0025] Rotational power (rotational torque) is transmitted to the inner member 12 from the coupling 50. The coupling 50 has a cup portion 51 and a shaft portion 52 that extends from the cup portion 51 to one side in the axial direction. The shaft portion 52 passes through the through hole 27 of the inner shaft 16. The cup portion 51 has a bottomed cylindrical shape that opens to the other side in the axial direction. The cup portion 51 has a larger diameter than the shaft portion 52. The side surface 55 on one side in the axial direction of the cup portion 51 is in surface contact with the side surface 18 on the other side in the axial direction of the inner ring 17.

[0026] The shaft portion 52 has a splined shaft portion 53 that spline-fits with the splined hole portion 28 of the inner shaft 16, and a non-splined shaft portion 54 that does not spline-fit with the inner shaft 16. The non-splined shaft portion 54 and the non-splined hole portion 29 face each other in the radial direction. The boundary between the splined shaft portion 53 and the non-splined shaft portion 54 is located on the other axial side from the center of the ball 13 of the row on the other axial side. The non-splined shaft portion 54 is shorter in the axial direction compared to the conventional (see Figure 3). A male threaded portion 56 is provided on one axial side of the shaft portion 52.

[0027] As described above, the bearing device 10 of this embodiment comprises an outer member 11, an inner member 12, and a plurality of balls 13. The inner member 12 has a flange portion 26 for mounting the wheel 7 on one axial side. The inner member 12 is provided with a through hole 27 that penetrates in the axial direction. The joint 50 has a cup portion 51 that contacts the inner member 12 from the other axial side, and a shaft portion 52 that penetrates the through hole 27. The joint 50 and the inner member 12 can rotate together by spline fitting of the shaft portion 52 and the inner member 12.

[0028] The bearing device 10 includes a fastening member 30 for connecting the coupling 50 and the inner member 12. Figure 2 is a cross-sectional view showing the fastening member 30 and its surroundings. The fastening member 30 is an annular member and functions as a nut. That is, the fastening member 30 has a female threaded portion 31 on its inner circumference that screws onto the male threaded portion 56 of the shaft portion 52. The female threaded portion 31 is configured to have a threaded hole that opens in the center of the annular fastening member 30.

[0029] The fastening member 30 has a recess 35 that opens on one side in the axial direction. The recess 35 has a shape that recesses from one side in the axial direction to the other side in the axial direction. The recess 35 has a bottomed rectangular hole-shaped portion (rectangular hole portion 36). With this configuration, a jig (not shown) can be fitted into the recess 35, and by rotating the jig, the fastening member 30 can be easily rotated around the center line C. The rectangular hole shape is, for example, a hexagonal hole shape or an octagonal hole shape.

[0030] The fastening member 30 has a contact surface 32 that contacts the inner shaft 16 from one axial side by screwing the female thread portion 31 with the male thread portion 56. The fastening member 30 has a tapered outer surface 32a as the contact surface 32 that contacts the tapered hole 19. The tapered outer surface 32a and the threaded hole of the female thread portion 31 are coaxial with a common center line L of the fastening member 30.

[0031] In this disclosure, "coaxial" includes cases where substantially acceptable machining errors occur, or where acceptable deviations occur due to such errors.

[0032] By tightening the female thread portion 31 onto the male thread portion 56, the contact surface 32 comes into close contact with the tapered hole 19. In this state, the center line L of the fastening member 30 coincides with the center line C of the bearing device 10. As described above (see Figure 1), the cup portion 51 of the joint 50 contacts the inner ring 17 of the inner member 12 from the other axial side. The greater the tightening torque of the fastening member 30 on the male thread portion 56, the greater the axial force (axial force) applied to the shaft portion 52 of the joint 50. Thus, the fastening member 30 functions as a nut that connects the joint 50 and the inner member 12 (inner shaft 16).

[0033] As described above (see Figure 2), the fastening member 30 has a tapered outer surface 32a as the contact surface 32. Therefore, when the fastening member 30 is tightened onto the male threaded portion 56, the axial force is applied to the shaft portion 52, and a portion of the tightening force of the fastening member 30 is applied to the inner member 12 (inner shaft 16) as a radial force. In other words, when the fastening member 30 is tightened with the same torque as the conventional nut 95 (see Figure 3), the axial force applied to the shaft portion 52 is reduced in this embodiment compared to the conventional example. As a result, as will be explained later, it is possible to suppress the generation of abnormal noises that may occur between the cup portion 51 and the inner ring 17.

[0034] The state in which the fastening member 30 is tightened onto the male threaded portion 56, thereby integrating the joint 50 and the inner member 12 (bearing device 10), is referred to as the assembled state. In this assembled state, the fastening member 30 has a cylindrical portion 33 that protrudes axially from the flange portion 26 to one side. The cylindrical portion 33 has a cylindrical outer surface 34 that is coaxial with the center line L of the female threaded portion 31. The cylindrical outer surface 34 has a cylindrical shape centered on the center line L. A rectangular hole portion 36 is provided on the inner circumference side of the cylindrical portion 33. The recess 35 of the fastening member 30 has a surface 37 that tapers in diameter in the other axial direction from the rectangular hole portion 36, and this surface 37 connects to the threaded hole of the female threaded portion 31.

[0035] In the assembled state described above, the end face 57 on one axial side of the shaft portion 52 is within the range of the recess 35. In the configuration shown in Figure 2, the shaft portion 52 penetrates the female thread portion 31 on one axial side, but its end face 57 is located on the other axial side of the mounting surface 26a of the flange portion 26. In other words, the shaft portion 52 is shorter than in the conventional configuration (see Figure 3), contributing to weight reduction.

[0036] As described above, in the bearing device 10 of this embodiment (see Figure 1), the coupling 50 and the inner member 12 can rotate together. The cup portion 51 of the coupling 50 contacts the inner ring 17 of the inner member 12 from the other axial side. A male threaded portion 56 is provided on one axial side of the shaft portion 52 of the coupling 50. The bearing device 10 is equipped with a fastening member 30, which has a female threaded portion 31 that screws into the male threaded portion 56. By screwing the female threaded portion 31 into the male threaded portion 56, the fastening member 30 has a contact surface 32 that contacts the inner shaft 16 of the inner member 12 from one axial side.

[0037] The fastening member 30 has a cylindrical portion 33 that protrudes axially to one side from the flange portion 26. The cylindrical portion 33 has a cylindrical outer surface 34 that is coaxial with the center line L of the female thread portion 31. By screwing the female thread portion 31 of the fastening member 30 onto the male thread portion 56 of the joint 50, the joint 50 and the inner member 12 become one unit.

[0038] Here, we will describe the case where the bearing device 10 is attached to the body of an automobile. During driving, various loads act on the bearing device 10, for example, from the wheel 7 through the flange portion 26. As a result, the flange portion 26 elastically deforms, for example, so as to be inclined with respect to the center line C. In this embodiment, since the fastening member 30 having the cylindrical portion 33 is a separate body (a different member) from the inner member 12 having the flange portion 26, the cylindrical portion 33 is less affected even if the flange portion 26 elastically deforms. Conventionally (see Figure 3), since the flange portion 94 and the cylindrical portion 93 are made of the same material, when the flange portion 94 elastically deforms, the cylindrical portion 93 is affected, and stress concentration occurs at the base portion 93a of the cylindrical portion 93. In contrast, in this embodiment (see Figure 1), it is possible to prevent the occurrence of such stress concentration.

[0039] When the wheel 7 is attached to the flange portion 26, the cylindrical portion 33 has the function of supporting the wheel 7 from its inner circumference. The cylindrical outer surface 34 of the cylindrical portion 33 is coaxial with the center line L of the female thread portion 31. Therefore, when the female thread portion 31 is screwed into the male thread portion 56 of the shaft portion 52, the degree of coaxiality between the cylindrical outer surface 34 of the cylindrical portion 33 and the shaft portion 52 is increased. As a result, it is possible to improve the accuracy of the coaxiality between the wheel 7, which is supported by the cylindrical portion 33 and attached to the flange portion 26, and the shaft portion 52. Since the center line of the shaft portion 52 becomes the rotational center line of the bearing device 10, the rotational accuracy of the wheel 7 is improved.

[0040] The fastening member 30 has a recess 35 that extends inward from one axial side to the other axial side. A female threaded portion 31 opens in the center of the recess 35. The recess 35 makes it possible to reduce the weight of the fastening member 30. In addition, as described above, the shaft portion 52 of the joint 50 is also shortened, and the unit of the joint 50 and the bearing device 10 is made lighter.

[0041] The cylindrical portion 33, located on the outer side of the vehicle, is visible from the outside of the vehicle and is therefore coated with rust-preventive paint. Conventionally (see Figure 3), rust-preventive paint is applied to the cylindrical portion 93, but not to the flange portion 94, requiring masking. In contrast, in this embodiment, the fastening member 30 having the cylindrical portion 33 is a separate component from the inner member 12 having the flange portion 26. Since the fastening member 30 can be rust-preventively painted on its own, masking of the flange portion 26 can be eliminated, reducing the amount of work required.

[0042] The manufacturing and assembly of each part of the bearing device 10 will be described. Conventionally (see Figure 3), before press-fitting the inner ring 92 into the body 91b of the hollow shaft portion 91, the outer surface of the cylindrical portion 93 is machined using a part of the body 91b as a reference to ensure accuracy. After that, the inner ring 92 is press-fitted into the body 91b. As a result, the diameter of the body 91b shrinks, which may affect the coaxiality between the hollow shaft portion 91 and the cylindrical portion 93.

[0043] In contrast, in this embodiment, the inner ring 17 is press-fitted onto the inner shaft 16, the shaft portion 52 is passed through the through hole 27 of the inner shaft 16, and then tightened by the fastening member 30. Therefore, the press-fitting of the inner ring 17 does not affect the coaxiality of the cylindrical portion 33. If the female thread portion 31 and the cylindrical outer surface 34 of the cylindrical portion 33 of the fastening member 30 are manufactured with high precision by machining, a high degree of coaxiality can be obtained on the cylindrical outer surface 34.

[0044] The female thread portion 31 of the fastening member 30 is formed by threading the female thread using the cylindrical outer surface 34 as a reference. As a result, the degree of coaxiality between the female thread portion 31 and the cylindrical outer surface 34 is high. By screwing such a fastening member 30 onto the male thread portion 56 of the shaft portion 52, the accuracy of the coaxiality between the cylindrical outer surface 34 and the shaft portion 42 is also improved.

[0045] In this embodiment, as described above, the inner member 12 has a tapered hole 19 on one axial side that expands in diameter toward the axial direction. The fastening member 30 has a tapered outer surface 32a as a contact surface 32 that contacts the tapered hole 19. With this configuration, when the female threaded portion 31 of the fastening member 30 is screwed onto the male threaded portion 56 of the joint 50 and tightened, a portion of the force due to the tightening becomes a radial force. In other words, even if the fastening member 30 is tightened with the same tightening torque as in the case of the nut 95 in the conventional example (Figure 3), the axial force (axial force) generated in the shaft portion 52 is mitigated (reduced).

[0046] In the bearing device 10 connected to the joint 50 shown in Figure 1, an abnormal noise may occur between the cup portion 51 and the inner ring 17 due to the mechanism described below. This abnormal noise is sometimes called a stick-slip noise or a clicking noise. Conventionally, this abnormal noise may be within the audible range.

[0047] The mechanism for generating abnormal noise will now be explained. The shaft portion 52 and the inner member 12 of the joint 50 are spline-fitted. Torque is transmitted between the spline shaft portion 53 and the spline hole portion 28, and no twisting occurs in the spline shaft portion 53. In contrast, twisting can occur at least one of the boundary portion between the shaft portion 52 and the cup portion 51, and the non-spline shaft portion 54.

[0048] Even if such twisting occurs, the side surface 18 of the inner ring 17 and the side surface 55 of the cup portion 51 are pressing against each other, and due to the frictional force (static friction) between them, slippage does not occur between the inner ring 17 and the cup portion 51 during steady-state driving of the vehicle. However, when the vehicle starts moving, the torque transmitted from the joint 50 to the inner member 12 may increase rapidly. In this case, a small amount of slippage occurs between the inner ring 17 and the cup portion 51 against the frictional force, and this results in the generation of an abnormal noise.

[0049] The greater the axial force (axial force) generated in the shaft portion 52 of the joint 50, the greater the frictional force and the lower the frequency of slippage. However, as the axial force increases, the torsional energy stored in the non-spline shaft portion 54 and the like increases accordingly. As a result, the frequency of abnormal noise decreases, but the stored energy increases, and when it exceeds a certain level, slippage occurs. In other words, it is considered impossible to completely suppress the slippage.

[0050] Therefore, in this embodiment, as described above, the axial force (axial force) generated in the shaft portion 52 is mitigated. In this case, the frictional force between the inner ring 17 and the cup portion 51 becomes smaller, and the frequency of minute slippage between them increases, but the accumulated energy becomes smaller, making it difficult for open-circuit noises that reach the audible range to occur. In other words, it becomes possible to suppress the generation of unpleasant noises.

[0051] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is not limited to the embodiments described above, and includes all modifications within the scope equivalent to the configurations described in the claims. [Explanation of symbols]

[0052] 7 wheels 10 Rolling bearing device for wheels 11 Outer member 12 Inner member 13 Balls (rolling elements) 19 Tapered bore 22a First outer orbital surface 22b Second outer raceway surface 24a First inner orbital surface 24b Second inner orbital plane 26 Flange section 27 Through hole 30 Fastening members 31 Female thread section 32 Contact surface 32a Tapered outer surface 33 Cylindrical section 34 Cylindrical outer surface 35 recess 50 Constant velocity universal joint (joint) 51 Cup section 52 Shaft 56 Male threaded section L center line

Claims

1. It comprises an outer member having an outer raceway surface on its inner circumference, an inner member having an inner raceway surface on its outer circumference, and rolling elements provided between the outer raceway surface and the inner raceway surface, The aforementioned inner member has a flange portion for wheel mounting on one axial side and is provided with a through hole that penetrates in the axial direction. A rolling bearing device for a wheel, comprising a joint having a cup portion that contacts the inner member from the other axial side and a shaft portion that passes through the through hole, and the inner member, wherein the joint and the joint are able to rotate as a single unit, The fastening member comprises a female threaded portion that screws into a male threaded portion provided on one axial side of the shaft portion, The fastening member is By screwing the female thread portion with the male thread portion, a contact surface is formed that contacts the inner member from one side in the axial direction, A cylindrical portion having a cylindrical outer surface that protrudes axially to one side from the flange portion and is coaxial with the center line of the female thread portion, The recess has a shape that is recessed from one axial side to the other axial side, and the female screw portion opens into a recess, It has, The recess has a rectangular hole-shaped portion, Rolling bearing device for wheels.

2. The inner member has a tapered hole on one axial side that expands in diameter toward the axial side, The fastening member has a tapered outer surface that contacts the tapered hole as the contact surface. A rolling bearing device for a wheel according to claim 1.

3. The wheel rolling bearing device according to claim 1 or claim 2, wherein the female threaded portion opens in the center of the recess.

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