Wheel bearing devices and vehicles

Abstract

To provide a wheel bearing device that can suppress the generation of abnormal noise while keeping the increase in weight to a minimum. [Solution] A recess 3h extending along the axial direction is formed on the inner circumferential surface of the shaft hole 3e in the hub ring 3 of the wheel bearing device 1, and a protrusion 28 extending along the axial direction and spline fitting with the recess 3h is formed on the outer circumferential surface of the stem portion 27 of the constant velocity universal joint 20, and the ratio of the axial distance E between the flange surface 3j of the wheel mounting flange 3 and the inner end surface 4b of the inner ring 4 to the pitch circle diameter D of the balls 8 constituting the inner ball row 5 and the outer ball row 6 is 0.8 ≤ (E / D) ≤ 0.94.

Description

Technical Field

[0001] The present invention relates to a wheel bearing device and a vehicle.

Background Art

[0002] Conventionally, as disclosed in Patent Document 1, there is known a wheel bearing device including a wheel bearing that rotatably supports a wheel in a suspension device of an automobile or the like, and a constant velocity joint that is coupled to the wheel bearing so as to be able to transmit torque. In such a wheel bearing device, the outer joint member of the constant velocity joint is spline-fitted to the inner diameter portion of the hub ring constituting the wheel bearing, whereby the wheel bearing and the constant velocity joint are coupled.

[0003] A driving force from a driving source of a vehicle is input to the constant velocity joint. In recent years, in addition to vehicles having an engine as a driving source, electric vehicles having a motor as a driving source tend to increase.

[0004] The driving torque from the motor in an electric vehicle is instantaneously input to the constant velocity joint as compared with the driving torque from the engine. Therefore, relative slippage suddenly occurs between the inner ring of the wheel bearing and the contact surface of the inner ring of the constant velocity joint, and abnormal noise due to stick-slip, commonly referred to as a rattling sound or a pecking sound, may occur.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] To suppress the generation of abnormal noise caused by slippage between the wheel bearing and the constant velocity universal joint, various methods have been employed, such as applying grease between the inner ring of the wheel bearing and the contact surface of the constant velocity universal joint, coating the contact surface of the constant velocity universal joint with a lubricant, or inserting a plate coated with a low-friction coating agent between the inner ring of the wheel bearing and the contact surface of the constant velocity universal joint. However, it has been difficult to sufficiently suppress the generation of abnormal noise caused by the instantaneous driving torque applied from the motor.

[0007] Furthermore, in order to suppress the generation of abnormal noise due to slippage between the wheel bearing and the constant velocity universal joint, it is conceivable to increase the fitting diameter of the spline fitting between the wheel bearing and the constant velocity universal joint in accordance with the magnitude of the driving torque applied to the constant velocity universal joint. However, simply increasing the fitting diameter between the wheel bearing and the constant velocity universal joint presents a problem, as it increases the weight of both the wheel bearing and the constant velocity universal joint.

[0008] This invention has been made in view of the above circumstances, and provides a wheel bearing device and vehicle that can suppress the increase in weight. [Means for solving the problem]

[0009] In other words, the wheel bearing device comprises an outer member having double rows of outer raceway surfaces on its inner circumference, a hub ring having a wheel mounting flange at one end in the axial direction for attaching a wheel, a small diameter stepped portion extending axially on its outer circumference, and a through hole penetrating axially in its inner diameter portion, and at least one inner ring press-fitted into the small diameter stepped portion of the hub ring, an inner member having double rows of inner raceway surfaces facing the double rows of outer raceway surfaces, and double rows of rolling elements rotatably housed between the raceway surfaces of the outer member and the inner member, and front A wheel bearing device comprising a constant velocity universal joint having a fitting portion that can be fitted into the through hole of the hub ring, wherein a recess extending along the axial direction is formed on the inner circumferential surface of the through hole in the hub ring, and a protrusion extending along the axial direction and spline fitting with the recess is formed on the outer circumferential surface of the fitting portion in the constant velocity universal joint, and the ratio of the axial distance E between the flange surface of the wheel mounting flange and the other axial end side surface of the inner ring to the pitch circle diameter D of the double row rolling elements is 0.8 ≤ (E / D) ≤ 0.94. [Effects of the Invention]

[0010] According to the present invention, it is possible to suppress the increase in weight. [Brief explanation of the drawing]

[0011] [Figure 1] This is a side cross-sectional view showing a wheel bearing device. [Figure 2] This is a side cross-sectional view showing the axle hole of the hub wheel and the stem portion of the outer joint member. [Figure 3] This is an axial cross-sectional view showing the recess in the hub hole and the protrusion in the stem portion of the hub wheel. [Figure 4] This is a side cross-sectional view showing a wheel bearing device with the shaft rotated to its maximum angle. [Figure 5] This is a side cross-sectional view showing a wheel bearing device according to the second embodiment. [Figure 6] This is a side cross-sectional view showing a wheel bearing device according to the third embodiment. [Figure 7] This is a side cross-sectional view showing a wheel bearing device according to the fourth embodiment.

Best Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

[0013] [Wheel Bearing Device] The wheel bearing device 1 shown in FIG. 1 is an embodiment of the wheel bearing device according to the present invention, and includes a wheel bearing 10 and a constant velocity joint 20.

[0014] In the following description, the axial direction represents the direction along the rotation axis X of the wheel bearing 10. Also, the outer side represents the wheel side of the wheel bearing device 1 when attached to the vehicle body on one side in the axial direction, and the inner side represents the vehicle body side of the wheel bearing device 1 when attached to the vehicle body on the other side in the axial direction.

[0015] (Wheel Bearing) The wheel bearing 10 rotatably supports a wheel in a suspension device of a vehicle such as an automobile. The wheel bearing 10 includes an outer ring 2 as an outer member, a hub ring 3 and an inner ring 4 as inner members, two rows of inner side ball rows 5 and outer side ball rows 6 as rolling element rows, an inner side seal member 9A, and an outer side seal member 9B.

[0016] An inner side opening 2a into which the inner side seal member 9A can be fitted is formed at the inner side end of the outer ring 2. An outer side opening 2b into which the outer side seal member 9B can be fitted is formed at the outer side end of the outer ring 2.

[0017] When the inner side seal member 9A is fitted into the inner side opening 2a, the inner side opening end of the annular space 15 formed by the outer ring 2 and the inner member is blocked. When the outer side seal member 9B is fitted into the outer side opening 2b, the outer side opening end of the annular space 15 is blocked.

[0018] On the inner peripheral surface of the outer ring 2, an inner-side outer raceway surface 2c and an outer-side outer raceway surface 2d are formed. On the outer peripheral surface 2o of the outer ring 2, a vehicle body mounting flange 2e for attaching the outer ring 2 to a vehicle body side member (knuckle) is integrally formed. The vehicle body mounting flange 2e is provided with bolt holes 2f through which fastening members for fastening the vehicle body side member and the outer ring 2 are inserted.

[0019] On the inner-side end portion of the outer peripheral surface 3o of the hub ring 3, a small-diameter stepped portion 3a that is reduced in diameter from the outer-side end portion and extends in the axial direction is formed. On the outer-side end portion of the hub ring 3, a wheel mounting flange 3b for attaching a wheel is integrally formed. The wheel mounting flange 3b is provided with bolt holes 3f into which hub bolts 3g are press-fitted.

[0020] The wheel mounting flange 3b has a flange surface 3j against which a brake rotor assembled to the wheel mounting flange 3b abuts. The flange surface 3j is the outer-side surface of the wheel mounting flange 3b.

[0021] On the hub ring 3, an outer-side inner raceway surface 3c is formed so as to face the outer-side outer raceway surface 2d of the outer ring 2. Further, on the hub ring 3, a lip sliding surface 3d with which an outer-side seal member 9B slides is formed on the base side of the wheel mounting flange 3b.

[0022] In the inner diameter portion of the hub ring 3, a shaft hole 3e that is formed along the axial direction and to which a constant velocity joint 20 is coupled is formed. The shaft hole 3e penetrates the hub ring 3 in the axial direction. The shaft hole 3e is an example of a through hole. An inner ring 4 is press-fitted into the small-diameter stepped portion 3a of the hub ring 3. The inner ring 4 has an inner-side end face 4b at the inner-side end portion. The inner-side end face 4b is an example of the other end side surface in the axial direction of the inner ring.

[0023] On the outer peripheral surface of the inner ring 4, an inner raceway surface 4a is formed. That is, on the inner side of the hub ring 3, the inner raceway surface 4a is constituted by the inner ring 4. The inner raceway surface 4a faces the inner-side outer raceway surface 2c of the outer ring 2.

[0024] The inner ball row 5 and the outer ball row 6, which are rolling elements, are composed of multiple balls 7, which are rolling elements, held by a cage 8. The inner ball row 5 is rotatably sandwiched between the inner raceway surface 4a of the inner ring 4 and the inner outer raceway surface 2c of the outer ring 2. The outer ball row 6 is rotatably sandwiched between the inner raceway surface 3c of the hub ring 3 and the outer outer raceway surface 2d of the outer ring 2. The inner ring 4 applies preload to the inner ball row 5 and the outer ball row 6, which are rolling elements.

[0025] In the wheel bearing 10, a double-row angular contact ball bearing is constructed from an outer ring 2, a hub ring 3 and an inner ring 4, an inner ball row 5, and an outer ball row 6. The wheel bearing 10 may also be constructed from a double-row tapered roller bearing.

[0026] (Constant velocity universal joint) The constant velocity universal joint 20 includes an outer joint member 21 having a track groove 25 formed on its inner circumferential surface, an inner joint member 22 having a track groove 22a formed on its outer circumferential surface opposite to the track groove 25, a ball 23 incorporated between the track groove 25 and the track groove 22a, and a cage 24 interposed between the inner circumferential surface of the outer joint member 21 and the outer circumferential surface of the inner joint member 22 to hold the ball 23.

[0027] The outer joint member 21 has a mouth portion 26 that houses the internal components consisting of the inner joint member 22, the ball 23, and the cage 24, and a stem portion 27 that extends integrally from the mouth portion 26 toward the outer side in the axial direction. The mouth portion 26 has a contact surface 26a at its outer end that abuts against the inner end face 4b of the inner ring 4.

[0028] The inner coupling member 22 has the shaft end of the shaft 31, which receives driving force from a drive source such as an engine or motor, press-fitted into it. The inner coupling member 22 and the shaft 31 are coupled in a way that allows torque transmission by spline fitting. The mouth portion 26 of the outer coupling member 21 supports the shaft 31 so that it can rotate with respect to the rotation axis X via the inner coupling member 22, the ball 23, and the cage 24.

[0029] [The fitting structure between the hub wheel and the stem] As shown in Figures 2 and 3, a recess 3h extending along the axial direction is formed on the inner circumferential surface of the shaft hole 3e of the hub wheel 3. Multiple recesses 3h are formed along the circumferential direction. On the outer circumferential surface of the stem portion 27 of the outer joint member 21, a protrusion 28 extending along the axial direction is formed, which spline-fits with the recesses 3h. Multiple protrusions 28 are formed along the circumferential direction. The multiple recesses 3h formed along the circumferential direction constitute a female spline, and the multiple protrusions 28 formed along the circumferential direction constitute a male spline. The stem portion 27 of the outer joint member 21 is an example of a fitting portion that can be fitted into the through hole of the hub wheel.

[0030] The recess 3h of the shaft hole 3e may be formed to have a smaller diameter than the protrusion 28 of the stem portion 27. In this case, the recess 3h has an overlap n with respect to the protrusion 28, and the protrusion 28 is press-fitted into it.

[0031] The stem portion 27 has a male threaded portion 27a on the outer side of the convex portion 28, and by screwing a nut 41 onto the male threaded portion 27a, the hub ring 3 and the outer joint member 21 are fixed in a state where the stem portion 27 is fitted into the shaft hole 3e. By screwing a nut 41 onto the male threaded portion 27a, it is possible to apply preload to the inner ring 4 by pressing it axially with the contact surface 26a of the outer joint member 21.

[0032] When fitting the stem portion 27 into the shaft hole 3e, if the stem portion 27 is moved from the inner side to the outer side of the shaft hole 3e, the recess 3h is formed to be smaller in diameter than the protrusion 28 and has a tightening allowance n for the protrusion 28, so the protrusion 28 is press-fitted into the recess 3h.

[0033] When the protrusion 28 is pressed into the recess 3h, the inner circumferential surface of the recess 3h is slightly machined by the protrusion 28, and the shape of the protrusion 28 is transferred to the inner circumferential surface of the recess 3h, accompanied by slight plastic and elastic deformation.

[0034] When the convex portion 28 is press-fitted into the concave portion 3h, a fitting contact area Y (see Figure 1) is formed between the spline-fitted concave portion 3h and the convex portion 28. At the fitting contact area Y, the outer circumferential surface of the convex portion 28 and the inner circumferential surface of the concave portion 3h are in close contact overall.

[0035] In this manner, the recess 3h is spline-fitted to the protrusion 28 with a tightening allowance n, and the spline-fitted recess 3h and protrusion 28 are in close contact overall in the axial direction. Because the protrusion 28 and recess 3h are in close contact overall at the fitting contact area Y, the allowable torque at the fitting contact area Y can be increased, and the axial length of the fitting contact area Y can be shortened, thereby making it possible to reduce the weight of the wheel bearing 10.

[0036] [Relationship of dimensions of various parts in a wheel bearing system] In the wheel bearing device 1, the pitch circle diameter of the spline formed by the mutually fitted recess 3h and protrusion 28 is A. The pitch circle diameter A of the spline is also the pitch circle diameter A of the recess 3h and the pitch circle diameter A of the protrusion 28.

[0037] The axial length of the protrusion 28 in the stem portion 27 is B, and the axial length of the recess 3h in the shaft hole 3e is C. The axial distance between the flange surface 3j of the wheel mounting flange 3b and the inner end face 4b of the inner ring 4 is E.

[0038] The pitch circle diameter of the balls 8 constituting the inner ball row 5 and the pitch circle diameter of the balls 8 constituting the outer ball row 6 are formed to be the same size, and the pitch circle diameter of the balls 8 constituting the inner ball row 5 and the outer ball row 6 is D. The pitch circle diameter D is the diameter of the circle that is centered on the rotation axis X and passes through the center P of the balls 8 in the inner ball rows 5 and 6. The pitch circle diameter D of the balls 8 is an example of the pitch circle diameter D of the rolling element.

[0039] The balls 8 constituting the inner ball row 5 and the balls 8 constituting the outer ball row 6 are arranged such that the ball-to-ball pitch is F in the axial direction. The ball-to-ball pitch F is the axial distance between the center P of the ball 8 in the inner ball row 5 and the center P of the ball 8 in the outer ball row 6. The ball-to-ball pitch F is an example of the rolling element pitch F.

[0040] In the wheel bearing device 1, the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h is set to 0.7 ≤ (C / A) ≤ 1.07.

[0041] In conventional wheel bearing devices, the ratio of the axial length B of the protrusion 28 to the pitch circle diameter A of the recess 3h is approximately 1.1 ≤ (B / A) ≤ 1.9, and the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h is approximately 1.25 ≤ (C / A) ≤ 1.8.

[0042] In contrast, in the wheel bearing device 1 of this embodiment, where the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h is 0.7 ≤ (C / A) ≤ 1.07, the diameters of the shaft hole 3e having the recess 3h and the stem portion 27 having the protrusion 28 are formed to be larger than in conventional wheel bearing devices, while the axial length C of the recess 3h and the axial length B of the protrusion 28 are formed to be smaller.

[0043] The protrusion 28 of the stem portion 27 twists in the rotational direction when a driving torque is applied to the constant velocity universal joint 20. However, the amount of twist of the protrusion 28 increases as the length of the stem portion 27 increases, and is therefore proportional to the axial length B of the protrusion 28. Furthermore, the amount of twist of the protrusion 28 is inversely proportional to the pitch circle diameter A of the protrusion 28, because the torsional rigidity of the stem portion 27 increases as the diameter of the stem portion 27 increases.

[0044] Furthermore, when a driving torque is applied to the constant velocity universal joint 20, relative rotational slip occurs between the inner end face 4b of the inner ring 4 in the wheel bearing 10 and the contact surface 26a of the mouth portion 26 in the constant velocity universal joint 20. In this case, if the amount of twisting of the convex portion 28 in the stem portion 27 decreases, the amount of relative slip between the inner end face 4b of the inner ring 4 and the contact surface 26a of the mouth portion 26 decreases.

[0045] Therefore, by making the diameter of the stem portion 27 larger and the axial length C of the recess 3h smaller, and setting the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h to the range of 0.7 ≤ (C / A) ≤ 1.07, the relative amount of slippage between the inner end face 4b and the contact surface 26a of the mouth portion 26 can be reduced, thereby suppressing the generation of abnormal noise due to stick-slip.

[0046] Here, the convex portion 28 of the stem portion 27 is generally given a torsional angle of about 10 to 30 minutes in the axial direction to prevent looseness when spline-fitted with the recess 3h of the hub wheel 3. Therefore, in conventional wheel bearing devices, there are areas where there is a gap between the spline-fitted convex portion 28 and the recess 3h. For example, if one side of the convex portion 28 in the rotational direction is in contact with the recess 3h at one axial end of the convex portion 28, there is a gap between the side of the convex portion 28 in the rotational direction and the recess 3h at the other axial end of the convex portion 28. Also, if the other side of the convex portion 28 in the rotational direction is in contact with the recess 3h at the other axial end of the convex portion 28, there is a gap between the other side of the convex portion 28 in the rotational direction and the recess 3h at one axial end of the convex portion 28.

[0047] Furthermore, since the twisting direction of the protrusion 28 is uniform in the wheel bearing device 1 of the same type, if the wheel bearing device 1 is used for the left and right wheels of a vehicle, the twisting direction of the protrusion 28 and the direction of the driving torque applied to the stem portion 27 will differ between the left and right wheels.

[0048] As a result, when driving torque is applied to the stem portion 27, the relative amount of slip in the rotational direction between the inner end face 4b of the inner ring 4 and the contact surface 26a of the mouse portion 26 will differ significantly between the left and right wheels, increasing the risk of abnormal noise due to stick-slip occurring in the wheel with the larger amount of slip.

[0049] However, in the wheel bearing device 1, the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h is set to the range of 0.7 ≤ (C / A) ≤ 1.07, and the relative amount of slip in the rotational direction between the inner end face 4b and the contact surface 26a of the mouse portion 26 is kept small, so it is possible to suppress the generation of abnormal noise due to stick-slip even in the wheel on the side with a large amount of slip.

[0050] Furthermore, by increasing the diameter of the stem portion 27 and forming a larger pitch circle diameter A of the convex portion 28, the stress on the tooth surfaces of the convex portion 28 and the concave portion 3h when a driving torque is applied to the stem portion 27 is reduced. This makes it possible to reduce the axial length of the wheel bearing 10 by forming a smaller axial length B of the convex portion 28 and a smaller axial length C of the concave portion 3h.

[0051] Therefore, in the wheel bearing device 1, the ball pitch F is made small so that the ratio of the axial distance E between the flange surface 3j and the inner end surface 4b to the ball pitch F is 2.85 ≤ (E / F), thereby reducing the axial length of the wheel bearing 10. By reducing the axial length of the wheel bearing 10 in this way, it is possible to reduce the weight of the wheel bearing 10.

[0052] Furthermore, in the wheel bearing device 1, the axial distance E is made small so that the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the pitch circle diameter D of the ball 8 is 0.8 ≤ (E / D) ≤ 0.94, thereby reducing the axial length of the wheel bearing 10. In this way, by reducing the axial length of the wheel bearing 10, it is possible to reduce the weight of the wheel bearing 10.

[0053] Thus, in the wheel bearing device 1, by setting the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h to the range of 0.7 ≤ (C / A) ≤ 1.07, setting the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the ball pitch F to the range of 2.85 ≤ (E / F), and setting the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the pitch circle diameter D of the ball 8 to the range of 0.8 ≤ (E / D) ≤ 0.94, it is possible to suppress the generation of abnormal noise due to stick-slip while suppressing an increase in weight.

[0054] Furthermore, in the wheel bearing device 1, the spline-fitted recess 3h and protrusion 28 are spline-fitted with a tightening allowance n and are in close contact overall in the axial direction. Therefore, compared to the case where the spline fitting is performed without being in close contact overall, the stress resistance when a driving torque is applied to the stem portion 27 is improved.

[0055] Therefore, the ratio of the axial length B of the convex portion 28 to the pitch circle diameter A of the concave portion 3h is 0.32 By making the axial length B of the protrusion 28 smaller so that ≤ (B / A) ≤ 0.6, it is possible to reduce the axial length of the wheel bearing 10. In this way, by reducing the axial length of the wheel bearing 10, it is possible to reduce the weight of the wheel bearing 10.

[0056] In the wheel bearing device 1, even if the spline-fitted recess 3h and the protrusion 28 are not in close contact overall, by setting the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h to the range of 0.7 ≤ (C / A) ≤ 1.07, setting the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the ball pitch F to the range of 2.85 ≤ (E / F), and setting the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the pitch circle diameter D of the ball 8 to the range of 0.8 ≤ (E / D) ≤ 0.94, it is possible to suppress the generation of abnormal noise due to stick-slip while suppressing an increase in weight.

[0057] In the wheel bearing device 1, the shaft diameter of the shaft 31 in the constant velocity universal joint 20 is G. As shown in Figure 4, the shaft 31 can be rotated relative to the mouse portion 26 within the range R in which the shaft 31 contacts the mouse portion 26, and when the shaft 31 is rotated by the maximum angle relative to the mouse portion 26, the contact point 31a of the shaft 31 contacts the mouse portion 26. The shaft diameter G is the shaft diameter of the portion of the shaft 31 that includes the contact point 31a, and is the minimum shaft diameter of the shaft 31.

[0058] The size of the stem portion 27 of the constant velocity universal joint 20 and the shaft diameter G of the shaft 31 are preferably determined according to the magnitude of the driving torque loaded from a drive source such as a motor. However, in a constant velocity universal joint 20 that spline-fits to a wheel bearing 10, the pitch circle diameter A of the convex portion 28 in the stem portion 27 and the shaft diameter G of the shaft 31 are set such that the ratio of the pitch circle diameter A of the convex portion 28 to the shaft diameter G is 1.1 ≤ (A / G) ≤ 1.41.

[0059] This makes it possible to secure the required shaft diameter G of the shaft 31 in the wheel bearing device 1, thereby ensuring a safety factor against the driving torque applied to the constant velocity universal joint 20, and ensuring the torsional rigidity of the shaft 31.

[0060] [Second embodiment of a wheel bearing device] The wheel bearing device 1 can also be configured as the wheel bearing device 1A according to the second embodiment. As shown in Figure 5, the wheel bearing device 1A differs from the wheel bearing device 1 in that it has a wheel bearing 10A having a hub wheel 3A instead of a wheel bearing 10 having a hub wheel 3.

[0061] In the wheel bearing 10A, the inner ring 4, which is press-fitted into the small-diameter stepped portion 3a of the hub ring 3A, is fixed by being crimped by the hub ring 3A, and the hub ring 3A has a crimping portion 3k for crimping the inner end face 4b of the inner ring 4. The inner ring 4 is crimped by the crimping portion 3k, thereby applying preload to the inner ball row 5 and the outer ball row 6.

[0062] In the wheel bearing 10A, the crimped portion 3k of the hub ring 3A and the contact surface 26a of the mouse portion 26 are in contact. The other components of the wheel bearing 10A and the hub ring 3A are the same as those of the wheel bearing 10 and the hub ring 3, so the same reference numerals are used and their explanation is omitted.

[0063] In a configuration such as the wheel bearing 10A, where the inner ring 4 is crimped by the crimping portion 3k, preload is applied by crimping the inner ring 4. Therefore, there is no need to apply preload by pressing the inner ring 4 with the axial force when the nut 41 is screwed onto the male threaded portion 27a of the stem portion 27.

[0064] Therefore, when screwing the nut 41 onto the male threaded portion 27a, it is not necessary to generate a large axial force, and the contact pressure between the crimped portion 3k of the hub wheel 3A and the contact surface 26a of the mouth portion 26 can be reduced. By reducing the contact pressure between the crimped portion 3k and the contact surface 26a, the occurrence of stick-slip between the crimped portion 3k and the contact surface 26a is suppressed, and the generation of abnormal noise due to stick-slip can be suppressed.

[0065] In the wheel bearing device 1A, the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h can be set to the range of 0.7 ≤ (C / A) ≤ 1.07, the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the ball pitch F can be set to the range of 2.85 ≤ (E / F), and the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the pitch circle diameter D of the ball 8 can be set to the range of 0.8 ≤ (E / D) ≤ 0.94. This makes it possible to further suppress the generation of abnormal noise due to stick-slip while suppressing the increase in weight.

[0066] Furthermore, in the wheel bearing device 1A, the ratio of the axial length B of the protrusion 28 to the pitch circle diameter A of the recess 3h can be set to 0.32 ≤ (B / A) ≤ 0.6. This makes it possible to reduce the weight of the wheel bearing 10 while suppressing the generation of abnormal noise due to stick-slip.

[0067] Furthermore, in the wheel bearing device 1A, the ratio of the pitch circle diameter A of the protrusion 28 to the shaft diameter G can be set to 1.1 ≤ (A / G) ≤ 1.41. This makes it possible to further suppress the generation of abnormal noise due to stick-slip in the wheel bearing device 1A, while ensuring a safety factor against the driving torque loaded on the constant velocity universal joint 20 and ensuring the torsional rigidity of the shaft 31.

[0068] [Third Embodiment of a Wheel Bearing Device] The wheel bearing device 1A can also be configured as the wheel bearing device 1B according to the third embodiment. As shown in Figure 6, the wheel bearing device 1B differs from the wheel bearing device 1A in that it has a wheel bearing 10B having a hub wheel 3B instead of a wheel bearing 10A having a hub wheel 3A.

[0069] Hub wheel 3B differs from hub wheel 3A in that it has a wheel mounting flange 3m with threaded holes 3n instead of a wheel mounting flange 3b with bolted holes 3f. The threaded holes 3n are holes into which wheel bolts are screwed for securing the wheel and brake rotor that are assembled to the wheel mounting flange 3m. The axial thickness of the wheel mounting flange 3m is H.

[0070] In the wheel bearing 10B, the hub ring 3B can be made larger in diameter by replacing the wheel mounting flange 3b, which has bolt holes 3f into which the hub bolts 3g are press-fitted, with a wheel mounting flange 3m that has screw holes 3n into which the wheel bolts are screwed. This makes it possible to increase the outer diameter of the outer ring 2 when the axial length of the wheel bearing 10B is reduced, thereby ensuring the lifespan of the wheel bearing 10B.

[0071] The other components of the wheel bearing 10B and hub wheel 3B are the same as those of the wheel bearing 10A and hub wheel 3A, and therefore the same reference numerals are used and their descriptions are omitted.

[0072] In the wheel bearing device 1B, the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the axial thickness H of the wheel mounting flange 3m is set to 4.5 ≤ (E / H) ≤ 5.6. By setting it in this way, it is possible to secure the thickness H of the wheel mounting flange 3m even when the axial distance E in the wheel bearing device 1B is set to a small value.

[0073] In the wheel bearing device 1B, the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h can be set to the range of 0.7 ≤ (C / A) ≤ 1.07, the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the ball pitch F can be set to the range of 2.85 ≤ (E / F), and the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the pitch circle diameter D of the ball 8 can be set to the range of 0.8 ≤ (E / D) ≤ 0.94. This makes it possible to further suppress the generation of abnormal noise due to stick-slip while suppressing the increase in weight.

[0074] Furthermore, in the wheel bearing device 1B, the ratio of the axial length B of the protrusion 28 to the pitch circle diameter A of the recess 3h can be set to 0.32 ≤ (B / A) ≤ 0.6. This makes it possible to reduce the weight of the wheel bearing 10 while suppressing the generation of abnormal noise due to stick-slip.

[0075] Furthermore, in the wheel bearing device 1B, the ratio of the pitch circle diameter A of the protrusion 28 to the shaft diameter G can be set to 1.1 ≤ (A / G) ≤ 1.41. This makes it possible to further suppress the generation of abnormal noise due to stick-slip in the wheel bearing device 1B, while ensuring a safety factor against the driving torque loaded on the constant velocity universal joint 20 and ensuring the torsional rigidity of the shaft 31.

[0076] [Fourth embodiment of a wheel bearing device] The wheel bearing device 1B can also be configured as the wheel bearing device 1C according to the fourth embodiment. As shown in Figure 7, the wheel bearing device 1C differs from the wheel bearing device 1B in that it has a constant velocity universal joint 20A having a stem portion 27A instead of a constant velocity universal joint 20 having a stem portion 27.

[0077] The stem portion 27A has a female threaded portion 27b formed from the outer side toward the inner side, and by screwing a bolt 42 into the female threaded portion 27b, the stem portion 27A is fitted into the shaft hole 3e, and the hub wheel 3B and the constant velocity universal joint 20A are fastened together. In this way, the wheel bearing 10B and the constant velocity universal joint 20A are fixed together.

[0078] A locking surface 3p is formed at the outer end of the axle hole 3e in the hub wheel 3B, which is a surface perpendicular to the rotational axis X that is the axis of the axle hole 3e. In this embodiment, the bolt 42 is locked to the locking surface 3p of the hub wheel 3B via a washer 43, but if the necessary axial force can be obtained when the bolt 42 is screwed into the female thread portion 27b, the bolt 42 may be configured to lock directly to the locking surface 3p without the washer 43.

[0079] In this embodiment, since the locking surface 3p is formed on a surface perpendicular to the axis of the shaft hole 3e, it is possible to obtain the necessary axial force when the bolt 42 is screwed into the female thread portion 27b, and it is possible to stably maintain the fixed state between the wheel bearing 10B and the constant velocity universal joint 20A.

[0080] The other components of the constant velocity universal joint 20A and the stem portion 27A are the same as those of the constant velocity universal joint 20 and the stem portion 27, and therefore the same reference numerals are used and their descriptions are omitted.

[0081] In the wheel bearing device 1C, the ratio of the axial distance E between the flange surface 3j and the inner end surface 4b to the axial thickness H of the wheel mounting flange 3m can be set to 4.5 ≤ (E / H) ≤ 5.6. This makes it possible to secure the thickness H of the wheel mounting flange 3m even when the axial distance E in the wheel bearing device 1C is set to a small value.

[0082] In the wheel bearing device 1C, the ratio of the axial length C of the recess 3h to the pitch circle diameter A of the recess 3h can be set to the range of 0.7 ≤ (C / A) ≤ 1.07, the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the ball pitch F can be set to the range of 2.85 ≤ (E / F), and the ratio of the axial distance E between the flange surface 3j and the inner end face 4b to the pitch circle diameter D of the ball 8 can be set to the range of 0.8 ≤ (E / D) ≤ 0.94. This makes it possible to further suppress the generation of abnormal noise due to stick-slip while suppressing the increase in weight.

[0083] Furthermore, in the wheel bearing device 1C, the ratio of the axial length B of the protrusion 28 to the pitch circle diameter A of the recess 3h can be set to 0.32 ≤ (B / A) ≤ 0.6. This makes it possible to reduce the weight of the wheel bearing 10 while suppressing the generation of abnormal noise due to stick-slip.

[0084] Furthermore, in the wheel bearing device 1C, the ratio of the pitch circle diameter A of the protrusion 28 to the shaft diameter G can be set to 1.1 ≤ (A / G) ≤ 1.41. This makes it possible to further suppress the generation of abnormal noise due to stick-slip in the wheel bearing device 1C, while ensuring a safety factor against the driving torque loaded on the constant velocity universal joint 20A and ensuring the torsional rigidity of the shaft 31.

[0085] [Vehicles equipped with wheel bearing systems] The wheel bearing devices 1, 1A, 1B, and 1C can be used in vehicles powered by engines, motors, or other motors. In particular, by using the wheel bearing devices 1, 1A, 1B, and 1C in vehicles where the driving torque is instantaneously input to the constant velocity universal joints 20 and 20A, such as electric vehicles powered by motors, it is possible to effectively suppress the generation of abnormal noise due to stick-slip while keeping the weight increase of the wheel bearing devices 1, 1A, 1B, and 1C to a minimum.

[0086] Furthermore, by making the axial length of the wheel bearings 10, 10A, and 10B smaller, as in the wheel bearing devices 1, 1A, 1B, and 1C, for example, in the case of an FF (front-engine, front-wheel drive) vehicle, the pivot point on the wheel side of the constant velocity universal joints 20 and 20A moves closer to the wheel than in the conventional case, making it possible to suppress the maximum angle of the constant velocity universal joints 20 and 20A during steering and to suppress an increase in the minimum turning radius of the vehicle.

[0087] Although embodiments of the present invention have been described above, the present invention is not limited in any way to these embodiments, but is merely illustrative. It can be implemented in various other forms without departing from the spirit of the invention, and the scope of the present invention is indicated by the claims, and further includes all modifications within the meaning and scope of equivalents as described in the claims. [Explanation of Symbols]

[0088] 1, 1A, 1B, 1C Wheel bearing device 2 Outer ring 2c (Inner side) outer raceway surface 2d (Outer side) outer raceway surface 3, 3A, 3B Hub wheels 3a Small diameter stepped section 3b, 3m Wheel mounting flange 3c Inner raceway surface 3e shaft hole 3h recess 3j flange surface 3k crimping part 3n screw hole 4. Inner Ring 4a Inner raceway surface 4b Inner side end face 5. Inner ball row 6 Outer ball row 7 Ball 8 Cage 10, 10A, 10B Wheel bearings 20, 20A constant velocity universal joint 27 Stem section 28 Convex part 31 shafts A Pitch circle diameter Axial length of the protrusion B Axial length of recess C D-ball pitch circle diameter E. Axial distance between the flange surface and the inner end face of the inner ring. F Ball-to-ball pitch G shaft diameter H flange thickness in the axial direction n closing fee

Claims

1. A wheel bearing comprising an outer member having double rows of outer raceway surfaces on its inner circumference, a hub ring having a wheel mounting flange at one end in the axial direction for attaching a wheel, a small diameter stepped portion extending axially on its outer circumference, and a through hole penetrating axially in its inner diameter portion, and an inner member having double rows of inner raceway surfaces facing the double rows of outer raceway surfaces, and double rows of rolling elements rotatably housed between the raceway surfaces of the outer member and the inner member, A constant velocity universal joint having a fitting portion that can be fitted into the through hole of the hub wheel, A wheel bearing device equipped with, A recess extending along the axial direction is formed on the inner circumferential surface of the through hole in the hub ring. On the outer circumferential surface of the fitting portion of the constant velocity universal joint, a protrusion is formed that extends along the axial direction and spline-fits with the recess. A wheel bearing device characterized in that the ratio of the axial distance E between the flange surface of the wheel mounting flange and the other axial end side surface of the inner ring to the pitch circle diameter D of the double row of rolling elements is 0.8 ≤ (E / D) ≤ 0.

94.

2. The wheel bearing device according to claim 1, characterized in that the ratio of the axial length C of the recess to the pitch circle diameter A of the recess is 0.7 ≤ (C / A) ≤ 1.

07.

3. The wheel bearing device according to claim 1, characterized in that the ratio of the axial distance E to the pitch F between the rolling elements on one axial side and the rolling element on the other axial side in the double row of rolling elements is 2.85 ≤ (E / F).

4. The wheel bearing device according to claim 1, characterized in that the hub ring has a crimping portion for crimping the inner ring to the hub ring.

5. The spline-fitted recess and the protrusion are in close contact overall in the axial direction. The wheel bearing device according to claim 1, characterized in that the ratio of the axial length B of the protrusion to the pitch circle diameter A of the recess is 0.32 ≤ (B / A) ≤ 0.

6.

6. The constant velocity universal joint has a shaft to which torque is transmitted and which is connected to the fitting portion, and to which driving force is input. The wheel bearing device according to claim 1, characterized in that the ratio of the pitch circle diameter A of the protrusion to the shaft diameter G of the shaft is 1.1 ≤ (A / G) ≤ 1.

41.

7. The wheel mounting flange has a plurality of screw holes into which wheel bolts that secure the wheel and brake rotor are screwed. The wheel bearing device according to claim 1, characterized in that the ratio of the axial distance E to the axial thickness H of the wheel mounting flange is 4.5 ≤ (E / H) ≤ 5.

6.

8. The wheel bearing device according to any one of claims 1 to 7, Equipped with a motor that generates driving force, The vehicle is characterized in that the constant velocity universal joint is coupled to the fitting portion in a manner that allows for torque transmission and has a shaft to which the driving force from the motor is input.

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