Wheel bearing device

Abstract

To provide a wheel bearing device which allows easy machining so as to spline-fit a wheel bearing to a constant velocity universal joint.SOLUTION: In a wheel bearing device 1, a through hole 3e of a hub wheel 3 has a first hole 31 in which a spline-fittable recess 3h is formed, and a second hole 32 which has a diameter equal to or larger than that of the first hole 31. A protrusion 24 which can be spline-fitted to the recess 3h is formed on an outer peripheral surface of a stem section 23 in a constant velocity universal joint 20. The protrusion 24 has a first protrusion 25 which is spline-fitted to the recess 3h in a state of adhering to the whole of the recess, and a second protrusion 26 which is positioned on an outer side of the first protrusion 25 and can be spline-fitted to the recess 3h in a state of having a gap m with the recess in a radial direction, a circumferential direction or both of the radial direction and the circumferential direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wheel bearing device. [Background technology]

[0002] As disclosed in Patent Document 1, a wheel bearing device has been known that includes a wheel bearing that rotatably supports a wheel in a suspension system of an automobile or the like, and a constant velocity universal joint that is connected to the wheel bearing so as to be able to transmit torque.

[0003] In such a wheel bearing device, a recess extending along the axial direction is formed in the through hole of the hub wheel that constitutes the wheel bearing, and a protrusion extending along the axial direction is formed at the fitting portion of the constant velocity universal joint with the wheel bearing, and the wheel bearing and the constant velocity universal joint are connected by spline fitting between the recess of the wheel bearing and the protrusion of the constant velocity universal joint.

[0004] Furthermore, a guide recess is formed in the through hole of the hub wheel adjacent to the end of the recess on the side where the constant velocity universal joint is inserted. The guide recess is shaped so that when the convex portion of the constant velocity universal joint is fitted, a gap is formed in the radial or circumferential direction relative to the convex portion, and when the convex portion fits into the recess, it is guided along the guide recess, making it easy to position the convex portion relative to the recess. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5323338 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the through hole of the hub wheel is formed with a smaller diameter on the side opposite the guide recess relative to the recess than the part where the recess is formed. Therefore, when forming the recess and guide recess in the through hole, broaching, a common processing method, cannot be applied, and the processing for forming the recess and guide recess in the through hole of the hub wheel is complicated.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and provides a wheel bearing device that facilitates the processing required for spline fitting a wheel bearing and a constant velocity universal joint, and that allows the constant velocity universal joint to be easily fitted to the wheel bearing. [Means for solving the problem]

[0008] That is, the wheel bearing device is provided with: an inner member having a double-row outer raceway surface on its inner periphery; a hub ring having a wheel mounting flange for mounting a wheel at one axial end thereof, a small-diameter stepped portion extending axially on its outer periphery, and a through-hole passing through in the axial direction in its inner diameter portion; and at least one inner ring press-fitted into the small-diameter stepped portion of the hub ring, the inner member having a double-row inner raceway surface opposing the double-row outer raceway surface; and double-row rolling elements accommodated in a rollable manner between the raceway surfaces of the outer member and the inner member; and a constant velocity universal joint having a fitting portion that can be fitted into the through-hole of the hub ring. The through hole comprises a first hole having a recess that extends axially on its inner surface and can be splined, and a second hole located on one axial side of the first hole and having a diameter greater than that of the first hole. The outer peripheral surface of the mating portion of the constant velocity universal joint is formed with a protrusion that extends axially and can be splined into the recess, and the protrusion comprises a first protrusion that spline-fits to the recess in a state of full contact with the recess, and a second protrusion that is located on one axial side of the first protrusion and can be spline-fit with a gap in the radial direction, circumferential direction, or both radial and circumferential directions relative to the recess. [Effects of the Invention]

[0009] According to the present invention, the processing for spline-fitting the wheel bearing and the constant velocity universal joint can be facilitated, and the constant velocity universal joint can be easily fitted to the wheel bearing. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side cross-sectional view showing a wheel bearing device. [Figure 2] 4 is a side cross-sectional view showing the wheel bearing device in a state where the tip end of the stem portion is inserted into a through hole of the hub wheel. FIG. [Figure 3] 3(a) is a side cross-sectional view showing a state in which the second protrusion of the stem is fitted into the recess of the hub wheel, and FIG. 3(b) is a cross-sectional view taken along the line AA of FIG. 3(a). [Figure 4] 4(a) is a side cross-sectional view showing a state in which a first protrusion of the stem portion is press-fitted into a recess of the hub wheel, and FIG. 4(b) is a cross-sectional view taken along line BB of FIG. 4(a). [Figure 5] 4 is an enlarged side cross-sectional view showing a first protrusion, a second protrusion, and a groove of the stem portion. FIG. [Figure 6] 10 is a side cross-sectional view showing the wheel bearing device with the stem portion inserted into the through-hole and the outer end of the first protrusion positioned at the inner end of the recess. FIG. [Figure 7] FIG. 6 is a side cross-sectional view showing a wheel bearing device according to a second embodiment. [Figure 8] FIG. 10 is a side cross-sectional view showing a wheel bearing device according to a third embodiment. [Figure 9] FIG. 10 is a side cross-sectional view showing a wheel bearing device according to a fourth embodiment. [Figure 10] FIG. 10 is a side cross-sectional view showing a wheel bearing device according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0012] [Wheel bearing device] A wheel bearing device 1 shown in FIG. 1 is one embodiment of a wheel bearing device according to the present invention, and includes a wheel bearing 10 and a constant velocity universal joint 20.

[0013] In the following description, the axial direction refers to the direction along the rotation axis X of the wheel support bearing device 10. Additionally, the outer side refers to one side in the axial direction, which is the wheel side of the wheel support bearing device 1 when attached to the vehicle body, and the inner side refers to the other side in the axial direction, which is the vehicle body side of the wheel support bearing device 1 when attached to the vehicle body.

[0014] (Wheel bearings) The wheel bearing 10 rotatably supports a wheel in a suspension system for 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 rolling rows of inner ball rows 5 and outer ball rows 6, an inner seal member 9A, and an outer seal member 9B.

[0015] An inner side opening 2a is formed at the inner side end of the outer ring 2, into which an inner side seal member 9A can be fitted. An outer side opening 2b is formed at the outer side end of the outer ring 2, into which an outer side seal member 9B can be fitted.

[0016] The inner seal member 9A is fitted into the inner opening 2a, thereby closing the inner opening end of the annular space 15 formed by the outer ring 2 and the inner member. The outer seal member 9B is fitted into the outer opening 2b, thereby closing the outer opening end of the annular space 15.

[0017] An inner-side outer raceway surface 2c and an outer-side outer raceway surface 2d are formed on the inner peripheral surface of the outer ring 2. A vehicle body mounting flange 2e for mounting the outer ring 2 to a vehicle body member (knuckle) is formed integrally with the outer peripheral surface 2o of the outer ring 2. The vehicle body mounting flange 2e is provided with bolt holes 2f through which fastening members for fastening the outer ring 2 to the vehicle body member are inserted.

[0018] A small diameter step 3a that is smaller in diameter than the outer end and extends in the axial direction is formed at the inner end of the outer peripheral surface 3o of the hub wheel 3. A wheel mounting flange 3b for mounting a wheel is integrally formed at the outer end of the hub wheel 3.

[0019] The wheel mounting flange 3b has a screw hole 3f into which a wheel bolt for fixing the wheel and brake rotor to be assembled to the wheel mounting flange 3b is screwed.

[0020] The hub ring 3 is formed with an outer-side inner raceway surface 3c that faces the outer-side outer raceway surface 2d of the outer ring 2. The hub ring 3 also has a lip sliding surface 3d formed on the base side of the wheel mounting flange 3b, with which the outer-side seal member 9B slides.

[0021] A through hole 3e is formed in the inner diameter portion of the hub wheel 3 along the axial direction and is coupled to the constant velocity universal joint 20. The through hole 3e passes through the hub wheel 3 in the axial direction.

[0022] The through hole 3e has a first hole 31, a second hole 32, and a third hole 33. The first hole 31 is formed so that its inner diameter is uniform along the axial direction. The second hole 32 is located on the outer side of the first hole 31, and is formed so that its inner diameter is equal to or larger than the inner diameter of the first hole 31. In other words, the second hole 32 has a diameter equal to or larger than the first hole 31. A step surface 34 is formed between the first hole 31 and the second hole 32. The step surface 34 is a surface perpendicular to the rotation axis X, which is the axis of the first hole 31.

[0023] The third hole 33 is located on the inner side of the first hole 31, and the inner diameter of the third hole 33 is formed to be equal to or larger than the inner diameter of the first hole 31. In other words, the third hole 33 has a diameter equal to or larger than the first hole 31.

[0024] An inner ring 4 is press-fitted into the small diameter step 3a of the hub ring 3. The inner ring 4 has an inner end face 4b at its inner end. The inner ring 4, press-fitted into the small diameter step 3a of the hub ring 3, is fixed by being crimped by the hub ring 3, and the hub ring 3 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 a preload to the inner ball row 5 and the outer ball row 6.

[0025] An inner raceway surface 4a is formed on the outer peripheral surface of the inner ring 4. In other words, the inner raceway surface 4a is formed by the inner ring 4 on the inner side of the hub ring 3. The inner raceway surface 4a faces the outer raceway surface 2c on the inner side of the outer ring 2.

[0026] The inner ball row 5 and outer ball row 6, which are rolling rows, are formed by a plurality of balls 7, which are rolling elements, being held in a cage 8. The inner ball row 5 is rollably sandwiched between the inner raceway surface 4a of the inner ring 4 and the inner-side outer raceway surface 2c of the outer ring 2. The outer ball row 6 is rollably sandwiched between the inner raceway surface 3c of the hub ring 3 and the outer-side outer raceway surface 2d of the outer ring 2.

[0027] In the wheel support bearing 10, a double-row angular contact ball bearing is formed by the outer ring 2, hub ring 3, inner ring 4, inner ball row 5, and outer ball row 6. The wheel support bearing 10 may also be formed by a double-row tapered roller bearing.

[0028] (constant velocity universal joint) The constant velocity universal joint 20 has a shaft 21 , a mouth portion 22 , and a stem portion 23 .

[0029] The shaft 21 is an axial member to which driving force is input from a driving source such as an engine or a motor. The mouth portion 22 supports the shaft 21 so that it can rotate about the rotation axis X. The shaft 21 is coupled to the mouth portion 22 so that torque can be transmitted. The mouth portion 22 has an abutment surface 22a at its outer end that abuts against the crimped portion 3k of the hub wheel 3. The stem portion 23 is formed integrally with the mouth portion 22, and extends from the mouth portion 22 toward the outer side in the axial direction.

[0030] [Fitting structure between hub wheel and stem] As shown in Figures 2 to 4, recesses 3h extending in the axial direction are formed on the inner circumferential surface of the first hole 31 in the through hole 3e of the hub wheel 3. A plurality of recesses 3h are formed along the circumferential direction. The axial length of each recess 3h is L1.

[0031] Protrusions 24 that extend along the axial direction and can be spline-fitted into recesses 3h are formed on the outer peripheral surface of stem portion 23 of constant velocity universal joint 20. A plurality of protrusions 24 are formed along the circumferential direction.

[0032] A female spline is formed by a plurality of recesses 3h formed along the circumferential direction, and a male spline is formed by a plurality of protrusions 24 formed along the circumferential direction. The stem portion 23 of the constant velocity universal joint 20 is an example of a fitting portion that can be fitted into a through hole of a hub wheel.

[0033] In the through hole 3e of the hub wheel 3, the second hole 32 and the third hole 33 located on both axial sides of the first hole 31 in which the recess 3h is formed have a diameter equal to or larger than that of the first hole 31, so when forming the recess 3h on the inner circumferential surface of the first hole 31, the recess 3h can be formed by broaching, making it easy to process the recess 3h. In this way, it is possible to easily process the wheel bearing 10 and the constant velocity universal joint 20 for spline fitting.

[0034] The protrusion 24 has a first protrusion 25 and a second protrusion 26 located on the outer side of the first protrusion 25. The first protrusion 25 and the second protrusion 26 are formed so as to be positioned at the same phase in the circumferential direction.

[0035] The first protrusion 25 is formed to have a larger diameter than the recess 3h and has an interference n with respect to the recess 3h. The first protrusion 25 can be press-fitted into the recess 3h, thereby fitting in a state of tight contact with the recess 3h as a whole.

[0036] The second protrusions 26 are formed with a smaller diameter than the recesses 3h, and are configured to be spline-fittable with a gap between them. The second protrusions 26 are mainly guided by the recesses 3h when the protrusions 24 and the recesses 3h are spline-fitted together, and are used to align the phases of the recesses 3h and the first protrusions 25 in the circumferential direction.

[0037] 5, the first protrusion 25 and the second protrusion 26 are spaced apart in the axial direction, and a groove 27 is formed between the first protrusion 25 and the second protrusion 26, recessed toward the inner diameter side of the first protrusion 25 and the second protrusion 26. The axial length of the groove 27 is L2. The axial length L2, which is the size of the axial distance between the first protrusion 25 and the second protrusion 26, is smaller than the axial length L1 of the recess 3h.

[0038] The first convex portion 25 and the second convex portion 26 can be formed, for example, by rolling the outer peripheral surface of the stem portion 23. Furthermore, the groove portion 27 can be formed by, after the first convex portion 25 and the second convex portion 26 are formed, performing machining such as cutting toward the inner diameter side on the portion between the first convex portion 25 and the second convex portion 26.

[0039] By forming groove 27 between first protrusion 25 and second protrusion 26 by machining, outer end surface 25a of first protrusion 25 facing groove 27 can be easily formed into a surface perpendicular to the axial direction. Furthermore, when groove 27 is formed by machining, outer end surface 25a of first protrusion 25 becomes a machined surface.

[0040] The portion of stem portion 23 where first protrusion 25 is formed is preferably a hardened portion H that has been subjected to a heat curing treatment. That is, first protrusion 25 is a hardened portion H that has been subjected to a heat curing treatment. In this case, the entire first protrusion 25 can be formed as a hardened portion H. Alternatively, only the outer-side end portion including outer-side end surface 25a of first protrusion 25 can be formed as a hardened portion H. That is, at least the outer-side end portion of first protrusion 25 can be formed as a hardened portion H.

[0041] Furthermore, in addition to the portion of stem portion 23 where first protrusion 25 is formed, the portion of stem portion 23 where second protrusion 26 is formed can also be formed as hardened portion H that has been subjected to a thermal hardening treatment.

[0042] Various heat treatments such as induction hardening and carburizing can be used as the thermal hardening treatment for the first protrusion 25 and the second protrusion 26. Here, induction hardening is a hardening method that applies the principle of heating a conductive object by placing the part to be hardened inside a coil through which a high-frequency current flows and generating Joule heat through electromagnetic induction. Meanwhile, carburizing hardening is a hardening method in which carbon is diffused and penetrated into the surface of a low-carbon material, and then hardened.

[0043] On the other hand, the recessed portion 3h is formed in a portion of the hub wheel 3 that is an untreated material (raw material) that has not been subjected to a heat hardening treatment. In other words, the portion of the hub wheel 3 where the recessed portion 3h is formed can be formed as an untreated portion that has not been subjected to a heat hardening treatment.

[0044] The stem portion 23 has an external thread portion 23a at its outer end, and by threading a nut 41 onto the external thread portion 23a, the hub wheel 3 and the constant velocity universal joint 20 are fastened together with the stem portion 23 fitted into the first hole 31 of the through hole 3e. This fixes the wheel bearing 10 and the constant velocity universal joint 20 together. The external thread portion 23a is an example of a threaded portion.

[0045] When the nut 41 is threaded onto the male thread portion 23a of the stem portion 23, the abutment surface 22a of the mouth portion 22 of the constant velocity universal joint 20 abuts against the crimped portion 3k of the hub wheel 3, and the nut 41 is locked onto the stepped surface 34 of the hub wheel 3. In this case, the stepped surface 34, which serves as the seating surface for the nut 41, is formed on a surface perpendicular to the axis of the first hole 31, so that the necessary axial force can be obtained when the nut 41 is threaded onto the male thread portion 23a, and the fixed state between the wheel bearing 10 and the constant velocity universal joint 20 can be stably maintained.

[0046] In the wheel bearing device 1, when fitting the stem portion 23 of the constant velocity universal joint 20 to the hub wheel 3, the stem portion 23 is inserted into the through hole 3e of the hub wheel 3 from the inner side, and then a nut 41 is screwed onto the male threaded portion 23a and the stem portion 23 is pulled to the outer side of the through hole 3e, thereby making it possible to fit the convex portion 24 of the stem portion 23 to the concave portion 3h of the hub wheel 3.

[0047] In this case, when the stem portion 23 is inserted into the through-hole 3e of the hub wheel 3 from the inner side, as shown in Figure 3, first the second protrusion 26 of the stem portion 23 is spline-fitted into the recess 3h of the hub wheel 3. The second protrusion 26 is formed with a smaller diameter than the recess 3h, and a gap m is formed between the second protrusion 26 and the recess 3h in the circumferential and radial directions.

[0048] As a result, when fitting the convex portion 24 of the stem portion 23 into the concave portion 3h of the hub wheel 3, the second convex portion 26 is guided by the concave portion 3h, making it possible to determine the circumferential phase of the convex portion 24 and the concave portion 3h. Therefore, the convex portion 24 can be fitted into the concave portion 3h easily and reliably, improving the ease of assembly of the constant velocity universal joint 20 to the hub wheel 3.

[0049] In this embodiment, the second convex portion 26 is spline-fitted with the recessed portion 3h with a gap m in both the circumferential and radial directions, but the second convex portion 26 can also be formed to be spline-fitted with the recessed portion 3h with a gap m only in the circumferential direction or with a gap m only in the radial direction.

[0050] When the stem portion 23 is further inserted toward the outer side of the through-hole 3e from the state shown in Fig. 3, the first convex portion 25 is fitted into the concave portion 3h as shown in Fig. 4. In this case, the first convex portion 25 is formed with a larger diameter than the concave portion 3h, and the concave portion 3h has an interference n with respect to the first convex portion 25, so the first convex portion 25 is press-fit into the concave portion 3h.

[0051] When the first protrusions 25 are press-fitted into the recesses 3h, the shape of the first protrusions 25 is transferred to the inner circumferential surface of the recesses 3h. In this case, the inner circumferential surface of the recesses 3h is very slightly cut by the first protrusions 25, and the shape of the first protrusions 25 is transferred to the inner circumferential surface of the recesses 3h while concomitantly causing very slight plastic deformation and elastic deformation.

[0052] When the first protrusion 25 is press-fitted into the recess 3h and the inner peripheral surface of the recess 3h is cut by the first protrusion 25, cutting of the recess 3h generates cutting chips 3j, but the generated cutting chips 3j can be held in the groove 27 between the first protrusion 25 and the second protrusion 26. This makes it possible to prevent the cutting chips 3j from scattering to various parts of the wheel bearing device 1.

[0053] When the first protrusion 25 is press-fitted into the recess 3h, the first protrusion 25 can be press-fitted into the recess 3h, for example, by pressing the constant velocity universal joint 20 toward the outer side in the axial direction relative to the hub wheel 3.

[0054] When the first protrusion 25 is press-fitted into the recess 3h and the first protrusion 25 and the recess 3h are spline-fitted, the outer peripheral surface of the first protrusion 25 and the inner peripheral surface of the recess 3h are in close contact with each other overall.

[0055] In this way, the first convex portion 25 and the concave portion 3h are spline-fitted with an interference n, and the spline-fitted first convex portion 25 and the concave portion 3h are in close contact with each other overall in the axial direction. By spline-fitting the first convex portion 25 and the concave portion 3h in a state where they are in close contact overall, it is possible to increase the allowable torque of the spline-fitted portion and shorten the axial length of the portion where the first convex portion 25 and the concave portion 3h are spline-fitted, thereby making it possible to reduce the weight of the wheel bearing 10.

[0056] In the wheel bearing device 1, when the stem portion 23 is spline-fitted to the hub wheel 3 and the abutment surface 22a of the mouth portion 22 abuts against the crimped portion 3k of the hub wheel 3, the second convex portion 26 is positioned on the outer side of the recessed portion 3h, and the engagement between the second convex portion 26 and the recessed portion 3h is released.

[0057] 6, when the stem portion 23 is inserted into the through-hole 3e and the outer end of the first convex portion 25 is positioned at the inner end of the concave portion 3h, the male thread portion 23a of the stem portion 23 protrudes an axial length L3 toward the outer side beyond the stepped surface 34 that forms the outer end of the first hole 31. In this case, the axial length L3 by which the male thread portion 23a protrudes from the stepped surface 34 is preferably set to a length equal to or greater than two pitches of the threads of the male thread portion 23a.

[0058] In this way, when the axial length L3 of the male threaded portion 23a is equal to or greater than the length corresponding to two pitches of the thread, the nut 41 can be screwed onto the male threaded portion 23a from the outer side to pull the stem portion 23 into the outer side of the through hole 3e, and the axial force generated when the nut 41 is screwed onto the male threaded portion 23a makes it possible to press the first convex portion 25 into the concave portion 3h.

[0059] This allows the work of fitting the constant velocity universal joint 20 to the hub wheel 3 and the work of fixing the constant velocity universal joint 20 to the hub wheel 3 to be performed simultaneously, improving the ease of assembling the constant velocity universal joint 20 to the hub wheel 3.

[0060] Furthermore, when fitting the convex portion 24 of the stem portion 23 into the recessed portion 3h of the hub wheel 3, the axial length L2 of the groove portion 27 is formed to be smaller than the axial length L1 of the recessed portion 3h, so that the first convex portion 25 can be started to be press-fitted into the recessed portion 3h with the second convex portion 26 fitted into the recessed portion 3h. This ensures that the phases of the first convex portion 25 and the recessed portion 3h are aligned when the first convex portion 25 is press-fitted into the recessed portion 3h, facilitating the fitting operation of the convex portion 24 into the recessed portion 3h.

[0061] In particular, since the first convex portion 25 and the second convex portion 26 are positioned at the same phase in the circumferential direction, it is possible to easily fit the first convex portion 25 into the recess 3h after fitting the second convex portion 26 into the recess 3h.

[0062] Furthermore, when the first protrusion 25 is press-fitted into the recess 3h, if the outer end surface 25a of the first protrusion 25 is a surface perpendicular to the axial direction, it is easy to perform cutting processing on the inner circumferential surface of the recess 3h using the first protrusion 25. In this embodiment, the groove 27 between the first protrusion 25 and the recess 3h is formed by machining, so that the outer end surface 25a of the first protrusion 25 can be easily processed into a surface perpendicular to the axial direction, which makes it possible to easily perform the fitting operation of the protrusion 25 and the recess 3h.

[0063] Furthermore, since the first convex portion 25 is a hardened portion H that has been subjected to a heat-hardening treatment, and the recess 3h is an untreated portion that has not been subjected to a heat-hardening treatment, when the first convex portion 25 is pressed into the recess 3h, the first convex portion 25 can easily cut the inner surface of the recess 3h, making it possible to facilitate the fitting operation of the convex portion 24 and the recess 3h.

[0064] In particular, when the first protrusion 25 is pressed into the recess 3h, the outer end of the first protrusion 25, which comes into contact with the recess 3h first, is formed as a hardened portion H, making it possible to easily cut the inner surface of the recess 3h.

[0065] [Second embodiment of wheel bearing device] The wheel bearing device 1 can also be configured as a wheel bearing device 1A according to a second embodiment. As shown in Fig. 7, the wheel bearing device 1A differs from the wheel bearing device 1 in that it includes a wheel bearing 10A having a hub ring 3A instead of the wheel bearing 10 having the hub ring 3.

[0066] The hub wheel 3A of the wheel support bearing 10A has a recess 3i instead of the recess 3h of the hub wheel 3. That is, the recess 3i is formed on the inner peripheral surface of the first hole 31 in the hub wheel 3A.

[0067] The axial length of the recess 3i in the hub wheel 3A is formed to be greater than the axial length of the recess 3h in the hub wheel 3, and when the abutment surface 22a of the mouth portion 22 abuts against the crimping portion 3k of the hub wheel 3A, both the first protrusion 25 and the second protrusion 26 are configured to fit into the recess 3i.

[0068] Other configurations of the wheel support bearing 10A and the hub wheel 3A are similar to those of the wheel support bearing 10 and the hub wheel 3, so the same reference numerals are used and the description will be omitted.

[0069] [Third embodiment of wheel bearing device] The wheel bearing device 1 can also be configured as a wheel bearing device 1B according to a third embodiment. As shown in Fig. 8, the wheel bearing device 1B differs from the wheel bearing device 1 in that it includes a wheel bearing 10B having a hub wheel 3B instead of the wheel bearing 10 having the hub wheel 3.

[0070] The hub ring 3B differs from the hub ring 3 having the crimped portion 3k in that it does not have the crimped portion 3k. In the wheel bearing 10, the inner ring 4 is only press-fitted into the small diameter step portion 3a of the hub ring 3B, and is not crimped by the hub ring 3B.

[0071] In the wheel bearing device 1B, when the nut 41 is threaded onto the male thread portion 23a of the stem portion 23, the abutment surface 22a of the mouth portion 22 in the constant velocity universal joint 20 abuts against the inner end surface 4b of the inner ring 4, and the nut 41 is locked onto the stepped surface 34 of the hub wheel 3. Furthermore, because the stepped surface 34, which serves as the seating surface for the nut 41, is formed on a surface perpendicular to the axis of the first hole 31, it is possible to obtain the necessary axial force when the nut 41 is threaded onto the male thread portion 23a. This makes it possible for the abutment surface 22a of the mouth portion 22 to press the inner ring 4 in the axial direction, thereby applying a preload to the inner ball row 5 and the outer ball row 6.

[0072] Other configurations of the wheel support bearing 10B and the hub wheel 3B are similar to those of the wheel support bearing 10 and the hub wheel 3, so the same reference numerals are used and the description will be omitted.

[0073] [Fourth embodiment of wheel bearing device] The wheel bearing device 1A can also be configured as a wheel bearing device 1C according to a fourth embodiment. As shown in Fig. 9, the wheel bearing device 1C differs from the wheel bearing device 1A in that it includes a wheel bearing 10C having a hub ring 3C instead of the wheel bearing 10A having the hub ring 3A.

[0074] The hub wheel 3C differs from the hub wheel 3A in that it has a wheel mounting flange 3m with bolt holes 3n instead of the wheel mounting flange 3b with screw holes 3f. Hub bolts 3p are press-fitted into the bolt holes 3n. In this way, it is also possible to configure the hub wheel 3C so that the hub bolts 3p are attached to the wheel mounting flange 3m.

[0075] Other configurations of the wheel support bearing 10C and the hub wheel 3C are similar to those of the wheel support bearing 10A and the hub wheel 3A, so the same reference numerals are used and the description will be omitted.

[0076] [Fifth embodiment of wheel bearing device] The wheel bearing device 1 can also be configured as a wheel bearing device 1D according to a fifth embodiment. As shown in Fig. 10, the wheel bearing device 1D differs from the wheel bearing device 1 in that it includes a constant velocity universal joint 20A having a stem portion 23A instead of the constant velocity universal joint 20 having the stem portion 23.

[0077] The stem portion 23A has a female thread portion 23b formed from the outer side surface toward the inner side, and by threading a bolt 42 into the female thread portion 23b, the hub wheel 3 and the constant velocity universal joint 20A are fastened together with the stem portion 23A fitted into the first hole 31 of the through hole 3e. This fixes the wheel bearing 10 and the constant velocity universal joint 20A together.

[0078] In this embodiment, the bolt 42 is engaged with the step surface 34 of the hub wheel 3 via the washer 43, but the bolt 42 may be configured to engage directly with the step surface 34 without the washer 43, as long as the necessary axial force can be obtained when the bolt 42 is screwed into the female thread portion 23b.

[0079] In this embodiment, too, the step surface 34 is formed on a surface perpendicular to the axis of the first hole 31, so that the necessary axial force can be obtained when the bolt 42 is screwed into the female thread portion 23b, and the fixed state between the wheel bearing 10 and the constant velocity universal joint 20A can be stably maintained.

[0080] Other configurations of the wheel bearing device 1D and the constant velocity universal joint 20A are similar to those of the wheel bearing device 1 and the constant velocity universal joint 20, so the same reference numerals are used and the description will be omitted.

[0081] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, which are merely examples, and it goes without saying that the present invention can be embodied in various other forms without departing from the spirit of the present invention. The scope of the present invention is indicated by the claims, and further includes the equivalent meanings set forth in the claims, and all modifications within the scope of the claims. [Explanation of symbols]

[0082] 1, 1A, 1B, 1C, 1D Wheel bearing device 2 outer ring 2c (inner side) outer raceway 2d (Outer side) outer raceway 3, 3A, 3B, 3C hub wheel 3a Small diameter stepped section 3b, 3m wheel mounting flange 3c Inner raceway surface 3e Through hole 3h recess 4. Inner Circle 4a Inner raceway surface 5 Inner ball row 6 Outer ball row 7 Ball 8 Cage 10, 10A, 10B, 10C Wheel bearings 20, 20A constant velocity universal joint 23, 23A stem section 23a Male thread 23b Female thread 24 Convex part 25 First convex part 25a Outer end face 26 Second convex part 27 Groove 31 Hole 1 32 2nd hole 33 Hole 3 41 Nut 42 volts H hardened part L1 (recess) axial length L2 Axial length (of groove)

Claims

1. a wheel bearing comprising an outer member having a double-row outer raceway surface on its inner periphery, a hub ring having a wheel mounting flange for mounting a wheel at one axial end thereof, a small-diameter stepped portion extending axially on its outer periphery, and a through-hole penetrating in the axial direction on its inner diameter portion, and at least one inner ring press-fitted into the small-diameter stepped portion of the hub ring, the inner member having double-row inner raceway surfaces facing the double-row outer raceway surfaces, and double-row rolling elements accommodated in a rollable manner 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 comprising: the through hole includes a first hole having an axially extending recess formed on an inner peripheral surface thereof, the recess being capable of being spline-fitted; and a second hole located on one axial side of the first hole and having a diameter equal to or greater than that of the first hole, a protrusion extending along an axial direction and capable of being spline-fitted into the recess is formed on an outer circumferential surface of the fitting portion of the constant velocity universal joint, The convex portion is a first protrusion that is spline-fitted into the recess in a state of being in close contact with the entire surface of the first protrusion; a second protrusion that is located on one side of the first protrusion in the axial direction and that can be spline-fitted with the recess with a gap in the radial direction, the circumferential direction, or both the radial and circumferential directions.

2. The first protrusion and the second protrusion are arranged at an interval in the axial direction, 2. The wheel bearing device according to claim 1, wherein the interval is smaller than the axial length of the recess.

3. 3. The wheel bearing device according to claim 2, wherein an end face of the first protrusion on the second protrusion side in the axial direction is a machined surface.

4. 4. The wheel bearing device according to claim 3, wherein an end of the first protrusion on the second protrusion side in the axial direction is a hardened portion that has been subjected to a heat hardening treatment.

5. 5. The wheel bearing device according to claim 1, wherein the first protrusions and the second protrusions are positioned at the same phase in the circumferential direction.

6. the convex portion is a hardened portion that has been subjected to a thermal hardening treatment, 5. The wheel bearing device according to claim 1, wherein the recess is a non-treated portion that has not been subjected to a heat hardening treatment.

7. the constant velocity universal joint has a threaded portion at one axial end of the fitting portion, In a state where one end of the first protrusion in the axial direction is positioned at the other end of the recess in the axial direction, 5. The wheel bearing device according to claim 1, wherein the threaded portion protrudes further toward one end than one axial end of the first hole.

8. the fitting portion of the constant velocity universal joint has a male thread portion onto which a nut can be screwed or a female thread portion onto which a bolt can be screwed, The wheel bearing device according to any one of claims 1 to 4, wherein the wheel bearing and the constant velocity universal joint are fixed together by threading the nut onto the male threaded portion or threading the bolt onto the female threaded portion.

9. A wheel bearing device as described in any one of claims 1 to 4, wherein the through hole is located on the other axial side of the first hole and has a third hole having a diameter equal to or larger than that of the first hole.

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