Hub assembly

Abstract

This hub assembly 41 includes a bearing device 1 for wheel and a constant-velocity universal joint 21 that are joined in a power transmittable manner. An inner ring 4 is press-fitted to an outer periphery of a hub ring 3 from an inboard side, and an annular connection member 14 is fitted to the outer periphery of the hub ring 3 in a state of abutting on the inner ring 4 in an axial direction on the inboard side. The inner ring 4 and the connection member 14 are held and fixed to the hub ring 3 by plastic deformation to the outside in a radial direction of an inboard-side end part of the hub ring 3, and an outside joint member 22 of the constant-velocity universal joint 21 and the connection member 14 are connected to each other by serration fitting.

Description

Hub Assembly

[0001] The present invention relates to a hub assembly, and more particularly to a hub assembly for a wheel bearing device and a constant velocity universal joint.

[0002] For example, a power transmission device that transmits engine power to wheels of an automobile or the like must transmit power from the engine to the wheels, and must also accommodate angular displacement for turning the vehicle, in addition to angular and axial displacement due to bouncing of the vehicle while driving. Therefore, a drive shaft of an automobile or the like generally has a sliding-type constant velocity joint on the differential side (inboard side) that can accommodate angular and axial displacement, and a fixed-type constant velocity joint on the drive wheel side (outboard side) that allows for a large operating angle, with both constant velocity joints connected by a shaft. Furthermore, the constant velocity joint on the drive wheel side (fixed-type constant velocity joint) is connected to a wheel bearing device that rotatably supports the drive wheel.

[0003] The power transmission structure between the wheel bearing device and the constant velocity universal joint described above generally has a serration-fit structure between the outer ring stem of the constant velocity universal joint and the wheel hub of the wheel bearing device (see, for example, Patent Document 1). However, recently, a structure has been proposed in which an outer joint member is connected via serrations to an inner ring member that is plastically joined to the wheel hub and fastened axially separably by threading means, in which a connecting portion protrudes from the inner ring member and has female serrations formed on this, and male serrations are formed on a shoulder portion of the outer joint member, and power is transmitted between the wheel bearing device and the constant velocity universal joint through a portion where these serrations fit together. In this case, the wheel hub and the inner ring member are plastically joined together, and the outer joint member is connected to the inner ring member via serrations, and the outer joint member is fastened axially separably to the inner ring member by threading means (see, for example, Patent Document 2).

[0004] In the case of a conventional power transmission structure (a serration fitting structure between an outer ring stem portion and a hub wheel), when high torque is input from the vehicle side, deformation such as torsion can cause the axial end face of the hub wheel to slip against the axial end face of the outer ring of the constant velocity universal joint, which are abutted against each other in the axial direction (a stick-slip phenomenon), which can result in the generation of abnormal noise and vibration.In contrast, if a structure is adopted in which serrations are provided on the outer periphery of the shoulder portion of the outer joint member of the constant velocity universal joint and on the inner periphery of the connecting portion protruding inboard of the inner ring member, and power is transmitted by the fitting of these serrations, the torsional rigidity of the torque transmission portion (serration fitting portion) is improved and the amount of misalignment at the axial abutment surfaces of the inner ring member and the outer joint member is reduced, making it possible to suppress the generation of abnormal noise and vibration.

[0005] JP 2022-129698 A JP 2007-69704 A

[0006] On the other hand, the serrated engagement structure between the inner ring member and the outer joint member described below is expected to be more difficult to implement in the vehicle assembly process than the conventional serrated engagement structure between the outer ring stem portion and the hub wheel. Specifically, the serrated engagement structure between the inner ring member and the outer joint member is characterized by plastic bonding between the inner periphery of the hub wheel and the outer periphery of the inner ring member as a structural feature of the wheel bearing device components. Therefore, in order to maintain the precision of the wheel bearing device after plastic bonding during the manufacturing process, high-precision processing, such as coaxiality between the hub wheel and the inner ring member, is required, which inevitably increases costs. Furthermore, since a predetermined load must be applied to the inner ring member during plastic bonding, it becomes difficult to control the preload of the bearing unit. This makes it difficult to actually produce such a product.

[0007] In view of the above circumstances, the technical problem to be solved in this specification is to provide a hub assembly of a wheel bearing device and a constant velocity universal joint that is capable of suppressing slippage such as stick-slip and that can be easily produced.

[0008] The above-mentioned problems are solved by a hub assembly according to the present invention, which is a hub assembly of a wheel bearing device and a constant velocity universal joint, the wheel bearing device comprising an outer member, a hub ring and an inner ring disposed radially inward of the outer member, and rolling elements disposed between the outer member and the hub ring and between the outer member and the inner ring, the inner ring being press-fitted onto the outer periphery of the hub ring from the inboard side, an annular connecting member being fitted onto the outer periphery of the hub ring with the inner ring abutting axially on its inboard side, the inner ring and connecting member being clamped and fixed to the hub ring by plastic deformation of the inboard end of the hub ring radially outward, and the outer joint member and connecting member of the constant velocity universal joint being interconnected by a serration fit.

[0009] As described above, in the hub assembly according to the present invention, the connecting member fitted onto the outer periphery of the hub wheel and the outer joint member of the constant velocity universal joint are interconnected by serration fitting, which improves torsional rigidity in the torque transmission portion (serration fitting portion). As a result, when high torque is input, the amount of misalignment at the axial contact portion between the inner member (hub wheel) and the outer joint member is reduced, making it possible to suppress slippage such as stick-slip, and thereby suppress the generation of abnormal noise and vibration caused by such slippage.

[0010] Furthermore, in the hub assembly according to the present invention, a connecting member is newly provided, which is a separate component from both the hub ring and the inner ring that constitute the wheel bearing device. The connecting member is clamped and fixed to the hub ring together with the inner ring by plastically deforming the inboard end of the hub ring radially outward. This configuration allows the wheel bearing device to be assembled using conventional methods. Furthermore, the hub ring and inner ring require substantially conventional levels of machining and assembly accuracy. The preload of the bearing portion can also be controlled using conventional means (crimping). As described above, the hub assembly according to the present invention can be mass-produced with productivity and production costs equivalent to those of conventional methods.

[0011] Furthermore, in the hub assembly according to the present invention, the connecting member may integrally have a ring portion that is fitted onto the outer periphery of the hub wheel, and a tubular portion that extends inboard from the outer diameter side of the ring portion, and a portion of the tubular portion that faces the outer joint member in the radial direction may be connected to the outer joint member by serration fitting.

[0012] By configuring the connecting member in this manner, it is possible to achieve connection for power transmission in an area on the largest possible diameter side, such as the outer peripheral surface of the shoulder portion of the outer joint member, and therefore it is possible to obtain torsional rigidity large enough to suppress slippage such as stick-slip even if the axial dimension is not so long.

[0013] In the hub assembly according to the present invention, a portion of the ring portion that faces the hub wheel in the radial direction may be connected to the hub wheel by serration fitting.

[0014] By connecting the hub wheel and the ring portion with serration fitting in this way, power can be transmitted reliably between the hub wheel and the connecting member without slippage, and power can be transmitted smoothly between the wheel bearing device and the constant velocity universal joint via the connecting member without loss.

[0015] In addition, in the hub assembly according to the present invention, a relatively hard uneven portion may be formed on either one of the radially opposing portions of the ring portion and the hub wheel, and the other radially opposing portion may be coupled by being embedded in the uneven portion.

[0016] This structure, which connects the hub wheel and the ring portion, also allows the hub wheel and the connecting member to engage in the circumferential direction, thereby ensuring smooth power transmission between the hub wheel and the connecting member. Furthermore, by using a structure in which the connection is achieved by biting into a relatively hard concave-convex portion, when the connecting member is clamped and fixed to the hub wheel by plastic processing such as crimping, it also bites into the concave-convex portion. This makes it possible to easily connect the connecting member and hub wheel so that power can be transmitted, without the need for circumferential alignment as with serration engagement.

[0017] In addition, in the hub assembly according to the present invention, a relatively hard uneven portion may be formed on one of the portions of the ring portion and the hub wheel that face each other in the axial direction, and the other portion that faces each other in the axial direction may be coupled by being embedded in the uneven portion.

[0018] This structure, which connects the hub wheel and the ring portion, also allows the hub wheel and the connecting member to engage in the circumferential direction, thereby ensuring smooth power transmission between the hub wheel and the connecting member. Furthermore, by using a structure in which the connection is achieved by biting into a relatively hard concave-convex portion, when the connecting member is clamped and fixed to the hub wheel by plastic processing such as crimping, it also bites into the concave-convex portion. This makes it possible to easily connect the connecting member and the hub wheel so that power can be transmitted, without the need for circumferential alignment as with serration engagement. In particular, by providing concave-convex portions on portions facing each other in the axial direction, the concave-convex portions can be more easily bitten into the concave-convex portion by the plastic deformation (plastic processing) described above.

[0019] The above-mentioned problems are also solved by a method for assembling a hub assembly according to the present invention. That is, this method is for assembling a hub assembly of a wheel bearing device and a constant velocity universal joint, and is characterized in that an inner ring is press-fitted onto the outer periphery of a hub wheel, which both constitute the wheel bearing device, and an annular connecting member is fitted onto the outer periphery of the hub wheel, and the connecting member is brought into contact with the inner ring from the inboard side, after which the inboard end of the hub wheel is plastically deformed radially outward to clamp and fix the inner ring and connecting member to the hub wheel, and after which the outer joint member and connecting member of the constant velocity universal joint are interconnected by serration fitting.

[0020] According to the assembly method of the present invention, as with the hub assembly of the present invention, a structure can be provided in which a connecting member fitted onto the outer periphery of the hub wheel and the outer joint member of the constant velocity universal joint are interconnected by serration fitting, thereby improving torsional rigidity in the torque transmission portion (serration fitting portion).As a result, when high torque is input, the amount of misalignment at the axial contact portion between the hub wheel and the outer joint member can be reduced, making it possible to suppress slippage such as stick-slip, and thereby suppress the generation of abnormal noise and vibration caused by such slippage.

[0021] Furthermore, in the method for assembling a hub assembly according to the present invention, a connecting member is newly provided, which is a separate component from both the hub ring and the inner ring that constitute the wheel bearing device. The connecting member is clamped and fixed to the hub ring together with the inner ring by plastically deforming the inboard end of the hub ring radially outward. This configuration allows the wheel bearing device to be assembled using conventional methods. Furthermore, the hub ring and the inner ring require substantially conventional levels of machining accuracy and assembly accuracy. The preload of the bearing portion can also be controlled using conventional means (crimping). As described above, the method for assembling a hub assembly according to the present invention makes it possible to produce this hub assembly with productivity and production costs equivalent to conventional methods.

[0022] As described above, according to the present invention, it is possible to provide a hub assembly of a wheel bearing device and a constant velocity universal joint that is capable of suppressing slippage such as stick-slip and that can be easily produced.

[0023] Fig. 1 is a cross-sectional view of a hub assembly of a wheel bearing device and a constant velocity universal joint according to a first embodiment of the present invention. Fig. 2 is an enlarged cross-sectional view of a main part of the hub assembly shown in Fig. 1. Fig. 3 is an enlarged cross-sectional view of a main part of a hub assembly of a wheel bearing device and a constant velocity universal joint according to a second embodiment of the present invention. Fig. 4 is an enlarged cross-sectional view of a main part of a hub assembly of a wheel bearing device and a constant velocity universal joint according to a third embodiment of the present invention.

[0024] A first embodiment of the present invention will now be described with reference to the drawings. First, the basic configurations of a wheel bearing device and a constant velocity universal joint will be described, followed by a detailed description of a power transmission structure and a connecting and fixing structure between the wheel bearing device and the constant velocity universal joint.

[0025] FIG. 1 shows a hub assembly 41 including a wheel bearing device 1 and a constant velocity universal joint 21. In this embodiment, the wheel bearing device 1 is formed as a unit and is detachably attached to the constant velocity universal joint 21, which is also formed as a unit. The wheel bearing device 1 mainly comprises an outer member 2, a hub ring 3, an inner ring 4, balls 5 as rolling elements, and a cage 6. Double-row outer raceways 7, 7 are formed on the inner periphery of the outer member 2, and a vehicle body mounting flange 8 for mounting to a knuckle (not shown) of the vehicle body is integrally formed on the outer periphery of the outer member 2. A wheel mounting flange 9 for mounting a wheel (not shown) is integrally formed on the outboard side of the hub ring 3, and an inner raceway 10 facing one of the double-row outer raceways 7, 7 of the outer member 2 is formed on the outer periphery, and a cylindrical small-diameter step 11 extending axially from the inner raceway 10 is formed. The inner ring 4 is press-fitted into this small diameter step 11, and an inner raceway surface 10 is formed on the outer periphery of the inner ring 4, which faces the other of the double row outer raceway surfaces 7, 7 of the outer member 2. In this case, the hub ring 3, the inner ring 4, and a connecting member 14, which will be described later, form an inner member 12. A plurality of balls 5, 5 are incorporated so as to roll freely between the double row outer raceway surfaces 7, 7 of the outer member 2 and the double row inner raceway surfaces 10, 10 of the inner member 12, and each ball 5 is housed in a cage 6. The inner ring 4 is fixed in the axial direction by a crimped portion 13 formed by plastically deforming the inboard end of the small diameter step 11 of the hub ring 3 radially outward.

[0026] The wheel bearing device 1 also has a connecting member 14. This connecting member 14 is formed separately from the outer member 2, the hub wheel 3, and the inner ring 4, and can be connected to the constant velocity universal joint 21 by serration fitting. In other words, the connecting member 14 is interposed between the wheel bearing device 1 and the constant velocity universal joint 21, and functions as an element for transmitting power.

[0027] The connecting member 14 is annular as a whole, and as shown in Figure 2, has a ring portion 15 that is fitted onto the outer periphery of the hub wheel 3, and a cylindrical portion 16 that extends inboard from the outer diameter side of the ring portion 15.

[0028] Of these, the ring portion 15 is fitted onto the outer periphery of the hub wheel 3 in a state of axial contact with the inner ring 4 on the inboard side thereof (see Figure 1). Then, due to radially outward plastic deformation of the axial end of the small diameter step portion 11 of the hub wheel 3, a crimped portion 13 is formed on the inboard side of the ring portion 15, and the inner ring 4 and ring portion 15 are clamped and fixed to the hub wheel 3 by this crimped portion 13 and the main body of the hub wheel 3 located on the outboard side of the inner ring 4 (see Figure 1).

[0029] In this embodiment, the radial dimension of the connecting member 14 (ring portion 15) is set to a predetermined size so that the entire end face of the inner ring 4 abuts against the end face of the connecting member 14 (ring portion 15). Also, in this embodiment, the inner diameter dimension of the tubular portion 16 (or the outer diameter dimension of the crimped portion 13) is set to a predetermined size so that a predetermined space (radial gap) is formed between the tubular portion 16 and the crimped portion 13 (see FIG. 2 for both).

[0030] Furthermore, a structure is provided between the connecting member 14 and the hub wheel 3 to enable power (particularly torque) transmission between the connecting member 14 and the hub wheel 3. In this embodiment, the portion of the ring portion 15 that faces the hub wheel 3 in the radial direction (here, the inner diameter side end portion 15a) is connected to the hub wheel 3 by serration fitting. In this case, a first serration portion 17 is formed on the inner diameter side end portion 15a of the ring portion 15. Furthermore, a second serration portion 18 is formed on the portion of the hub wheel 3 that faces the ring portion 15 in the radial direction (here, a region of the small diameter step portion 11 that is axially close to the crimped portion 13).

[0031] The serration portion 18 is fitted (engaged) with the first serration portion 17 by fitting the ring portion 15 onto the outer periphery of the small diameter step portion 11 of the hub wheel 3 while aligning it in the circumferential direction. This enables power (torque) to be transmitted in both directions between the hub wheel 3 and the connecting member 14.

[0032] Here, the first serration portion 17 is formed by circumferentially arranging a plurality of teeth 19 as a convex portion. Furthermore, in this embodiment, each tooth 19 extends along the axial direction of the ring portion 15 on which the first serration portion 17 is provided, and its cross-sectional shape is the same at any axial position. The inner diameter dimensions of each tooth 19 and the spaces between each tooth 19 (tooth roots) are the same at any axial position. Similar to the first serration portion 17, the second serration portion 18 is formed by circumferentially arranging a plurality of teeth 20 as a convex portion. Furthermore, in this embodiment, each tooth 20 extends along the axial direction of the small-diameter step portion 11 on which the second serration portion 18 is provided, and its cross-sectional shape is the same at any axial position. The outer diameter dimensions of each tooth 20 and the spaces between each tooth 20 (tooth roots) are the same at any axial position.

[0033] In this embodiment, the axial position and axial dimension of the second serration portion 18 are set so that, with the crimped portion 13 formed and the inner ring 4 and connecting member 14 clamped and fixed to the hub wheel 3, a portion of the outboard side of the second serration portion 18 does not fit with the first serration portion 17, in other words, so that the outboard end of the first serration portion 17 reliably fits with the second serration portion 18 (see FIG. 2). Furthermore, in order to minimize deformation of the second serration portion 18 provided on the outer periphery of the small diameter step portion 11 when the crimped portion 13 is formed, a relatively small diameter relief portion 13a is provided at the outboard end of the second serration portion 18 (see FIG. 2).

[0034] Of course, the above-described configuration of the serration portions 17, 18 is merely an example, and any configuration is possible as long as the hub wheel 3 and the connecting member 14 are connected so as to be capable of transmitting power by serration fitting.

[0035] These serration portions 17, 18 can be formed by various known methods (cutting, plastic working, etc.). The first serration portion 17 may be formed simultaneously with the molding of the ring portion 15, or may be formed by a separate process after the ring portion 15 is molded. Similarly, the second serration portion 18 may be formed simultaneously with the molding of the hub wheel 3 (small diameter step portion 11), or may be formed by a separate process after the small diameter step portion 11 is molded.

[0036] On the other hand, the constant velocity universal joint 21 mainly includes an outer joint member 22, an inner joint member 23, a cage 24, and torque transmission balls 25. The outer joint member 22 includes a cup portion 26 and a bottom portion 27 formed integrally with the cup portion 26 (see FIG. 1). In this case, a third serration portion 29 is formed on the outer periphery of a shoulder portion 28 corresponding to the radially outer region of the bottom portion 27. On the other hand, a fourth serration portion 30 is formed on a portion of the tubular portion 16 of the connecting member 14 that faces the third serration portion 29 in the radial direction. Therefore, the third serration portion 29 and the fourth serration portion 30 fit together, enabling power transmission between the outer joint member 22 and the connecting member 14 (see FIG. 2). For example, when rotational torque is input from a shaft (not shown) connected to the inner joint member 23 of the constant velocity universal joint 21, this rotational torque can be transmitted to the wheel mounting flange 9 via the constant velocity universal joint 21, the connecting member 14 of the wheel bearing device 1, and the hub wheel 3.

[0037] Here, the third serration portion 29 is formed by circumferentially arranging a plurality of teeth 31 as convex portions. In the present embodiment, each tooth 31 extends along the axial direction of the outer joint member 22 on which the third serration portion 29 is provided, and its cross-sectional shape is the same at any axial position. The inner diameter dimensions of each tooth 31 and the spaces between the teeth 31 (tooth roots) are the same at any axial position. Like the third serration portion 29, the fourth serration portion 30 is formed by circumferentially arranging a plurality of teeth 32 as convex portions. In the present embodiment, each tooth 32 extends along the axial direction of the cylindrical portion 16 on which the fourth serration portion 30 is provided, and its cross-sectional shape is the same at any axial position. The outer diameter dimensions of each tooth 32 and the spaces between the teeth 32 (tooth roots) are the same at any axial position.

[0038] In this embodiment, the axial positions and axial dimensions of the serration portions 29, 30 are set so that the third serration portion 29 fits into the fourth serration portion 30 over the entire axial length when the crimped portion 13 and the outer joint member 22 are in axial contact with each other (see FIG. 2 ).

[0039] Of course, the above-described configurations of the serration portions 29, 30 are merely examples. As long as the connecting member 14 and the outer joint member 22 are connected to each other by serration fitting so as to be capable of transmitting power, any configuration is possible.

[0040] The serration portions 29, 30 can be formed by various known methods (cutting, plastic working, etc.). The third serration portion 29 may be formed simultaneously with molding of the outer joint member 22, or may be formed by a separate process after molding the outer joint member 22. Similarly, the fourth serration portion 30 may be formed simultaneously with molding of the connecting member 14 (cylindrical portion 16), or may be formed by a separate process after molding the connecting member 14.

[0041] The wheel bearing device 1 and the constant velocity universal joint 21 configured as described above are fastened together in an axially separable manner by a bolt 33. Specifically, an internally threaded hole 34 is provided in the bottom 27 of the outer joint member 22, and with the wheel bearing device 1 and the constant velocity universal joint 21 butted together in the axial direction, the bolt 33 is inserted into a through hole 35 of the hub wheel 3 from the outboard side and screwed into the internally threaded hole 34, thereby joining them together.

[0042] The hub assembly 41 having the above configuration is assembled, for example, in the following manner.

[0043] First, a fully assembled (unitized) wheel bearing device 1 and constant velocity universal joint 21 are prepared. For the wheel bearing device 1, after assembling all elements except the inner ring 4 and connecting member 14, the inner ring 4 is press-fit onto the outer periphery of the hub wheel 3 before the crimped portion 13 is formed, and then the ring portion 15 of the connecting member 14 is fitted onto the outer periphery of the hub wheel 3 from the inboard side. At this time, the ring portion 15 is fitted onto the outer periphery of the hub wheel 3 while being aligned circumferentially, so that the first serration portions 17 on the inner diameter end portion 15a of the ring portion 15 fit into the second serration portions 18 on the outer periphery of the hub wheel 3. The ring portion 15 is fitted into the inner ring 4 in the axial direction.

[0044] After the inner ring 4 and ring portion 15 (connecting member 14) have been fitted onto the outer periphery of the hub wheel 3 as described above, the inboard end of the small diameter step 11 is subjected to plastic processing involving radially outward plastic deformation to form the crimped portion 13 shaped as shown in FIG. 1 . The inner ring 4 and connecting member 14 are then clamped and fixed in the axial direction between the outboard side of the hub wheel 3 (hub wheel 3 main body) and the crimped portion 13. When the connecting member 14 is clamped and fixed by crimping, a predetermined preload is applied to the bearing portion. This completes the assembly (unitization) of the wheel bearing device 1.

[0045] Thereafter, the wheel bearing device 1 and the constant velocity universal joint 21 are butted together in the axial direction to be integrated. Specifically, the outer joint member 22 is brought into axial contact with the crimped portion 13 of the hub wheel 3, and the fourth serration portion 30 provided on the inner peripheral surface 16a of the tubular portion 16 and the third serration portion 29 provided on the outer peripheral surface 28a of the shoulder portion 28 of the outer joint member 22 are fitted together with their circumferential positions aligned. Finally, the bolt 33 is screwed into the female threaded hole 34 of the outer joint member 22 until its flange 36 comes into axial contact with the hub wheel 3. This connects and fixes the wheel bearing device 1 and the constant velocity universal joint 21, and the serration fit between the third serration portion 29 and the fourth serration portion 30 enables bidirectional transmission of rotational power between the wheel bearing device 1 and the constant velocity universal joint 21.

[0046] As described above, in the hub assembly 41 according to this embodiment, the connecting member 14 fitted onto the outer periphery of the hub wheel 3 and the outer joint member 22 of the constant velocity universal joint 21 are connected to each other by serration fitting, which improves torsional rigidity in the torque transmission portion (serration fitting portion). Therefore, when high torque is input, for example, the amount of misalignment at the axial contact portion between the inner member 12 (in this embodiment, the crimped portion 13 of the hub wheel 3) and the outer joint member 22 can be reduced, making it possible to suppress slippage such as stick-slip, and thereby suppress the generation of abnormal noise and vibration caused by such slippage.

[0047] Furthermore, in the hub assembly 41 according to this embodiment, a connecting member 14 is newly provided, which is a separate component from both the hub ring 3 and the inner ring 4 that constitute the wheel support bearing device 1. The crimped portion 13 is formed by plastically deforming the inboard end of the hub ring 3 radially outward, and the connecting member 14 and the inner ring 4 are clamped and fixed to the hub ring 3 by this crimped portion 13 and the outboard side of the hub ring 3. This configuration allows the wheel support bearing device 1 to be assembled in a conventional manner. Furthermore, the hub ring 3 and the inner ring 4 require substantially conventional levels of machining accuracy and assembly precision. The preload of the bearing portion can also be controlled by the same means (crimping) as in the past. As described above, the hub assembly 41 according to this embodiment can be produced with productivity and production costs equivalent to those of conventional methods.

[0048] Furthermore, in this embodiment, the hub wheel 3 and the ring portion 15 of the connecting member 14 are connected by serration fitting, which ensures reliable power transmission between the hub wheel 3 and the connecting member 14 without slippage. This allows for smooth power transmission between the wheel bearing device 1 and the constant velocity universal joint 21 via the connecting member 14 without loss.

[0049] The above describes the first embodiment of the present invention, but the above-mentioned hub assembly of a wheel bearing device and a constant velocity universal joint and the assembly method thereof can also take other forms as long as they fall within the scope of the present invention.

[0050] For example, in the above embodiment, the hub wheel 3 and the ring portion 15 of the connecting member 14 are connected by serration fitting. However, the hub wheel 3 and the connecting member 14 can also be connected by other means. FIG. 3 shows an enlarged cross-sectional view of a main portion of a hub assembly 41 according to one example (a second embodiment of the present invention). As shown in FIG. 3 , in the hub assembly 41 according to this embodiment, a relatively hard first uneven portion 37 is formed on the inner diameter side end 15a of the ring portion 15 that faces the hub wheel 3 in the radial direction. The portion of the hub wheel 3 that faces the first uneven portion 37 engages with the first uneven portion 37, thereby forming a first plastic joint 38. For example, as shown in the figure, the first uneven portion 37 is formed by alternating a plurality of convex portions extending in the axial direction of the ring portion 15 with grooves between the convex portions in the circumferential direction. At least the portion of the hub wheel 3 that faces the first uneven portion 37 in the radial direction is formed relatively soft. As a result, a portion of the hub wheel 3 enters the relatively recessed portion of the first uneven portion 37 due to plastic flow, and they are connected to each other. In this case, the above-mentioned hardness difference can be achieved, for example, by subjecting the first uneven portion 37 of the ring portion 15 to a predetermined hardening treatment. Of course, if conditions such as cost and processing allow, the ring portion 15 (connecting member 14) may be made of a harder material than the hub wheel 3.

[0051] By using a structure in which the hub wheel 3 and the ring portion 15 are joined in this manner, the hub wheel 3 and the connecting member 14 can be engaged in the circumferential direction. This allows for smooth power transmission between the hub wheel 3 and the connecting member 14. Furthermore, by using a structure in which the connecting member is joined by biting into the relatively hard first uneven portion 37, when the connecting member 14 is clamped and fixed to the hub wheel 3 by plastic processing such as crimping, it can also be made to bite into the first uneven portion 37. This makes it possible to easily join the connecting member 14 and hub wheel 3 so that power can be transmitted, without the need for circumferential alignment as with serration fitting.

[0052] In principle, the shape of the first uneven portion 37 is arbitrary, and for example, although not shown, it may be formed so that multiple convex portions extend in a direction that forms a predetermined angle with respect to the axial direction of the ring portion 15. Alternatively, the first uneven portion 37 may be formed with multiple grooves that intersect in a chevron pattern, such as a shape obtained by knurling. In short, the first uneven portion 37 may have any shape as long as the ring portion 15 and the hub wheel 3 engage in the circumferential direction by biting into each other from the hub wheel 3 side, and rotational power can be transmitted between them via this engaged portion.

[0053] FIG. 4 shows an enlarged cross-sectional view of a main portion of a hub assembly 41 according to yet another embodiment (third embodiment) of the present invention. In the hub assembly 41 according to this embodiment, a relatively hard second uneven portion 39 is formed on the outboard end of the ring portion 15 axially facing the crimped portion 13 of the hub wheel 3. The portion of the crimped portion 13 axially facing the second uneven portion 39 bites into the second uneven portion 39, thereby forming a plastically bonded portion 40. The second uneven portion 39 is, for example, as shown in the figure, composed of a plurality of convex portions extending radially of the ring portion 15 and grooves between the convex portions, arranged alternately in the circumferential direction. At least the portion of the crimped portion 13 axially facing the second uneven portion 39 is formed relatively soft. As a result, a portion of the crimped portion 13 flows into the relatively concave portions of the second uneven portion 39 due to plastic flow, thereby bonding the two portions together. In this case, the above-mentioned hardness difference can be achieved by, for example, performing a predetermined hardening treatment on the second uneven portion 39 of the ring portion 15. Of course, if conditions such as cost and processing permit, the ring portion 15 (connecting member 14) may be formed of a harder material than the crimped portion 13.

[0054] By adopting a structure in which the hub wheel 3 and the ring portion 15 are coupled in this manner, the hub wheel 3 and the connecting member 14 can be engaged in the circumferential direction. This allows for smooth power transmission between the hub wheel 3 and the connecting member 14. Furthermore, by adopting a structure in which the coupling is achieved by biting into the relatively hard second concave-convex portions 39, when the coupling member 14 is clamped and fixed to the hub wheel 3 by plastic processing such as crimping, the coupling member 14 can also be bitten into the second concave-convex portions 39. This makes it possible to easily couple the connecting member 14 and the hub wheel 3 so as to transmit power, without the need for circumferential alignment as is required with serration fitting. In particular, by providing the second concave-convex portions 39 in portions that face each other in the axial direction, the coupling member 14 can be more easily bitten into the second concave-convex portions 39 by the above-mentioned plastic deformation (plastic processing to form the crimped portion 13).

[0055] In principle, the shape of each of the concave-convex portions 37, 39 is arbitrary. For example, although not shown, the first concave-convex portion 37 may have multiple convex portions extending in a direction that forms a predetermined angle with respect to the axial direction of the ring portion 15. The second concave-convex portion 39 may have multiple convex portions extending in a direction that forms a predetermined angle with respect to the radial direction of the ring portion 15. Alternatively, each of the concave-convex portions 37, 39 may have multiple grooves that intersect in a twill pattern, as in a shape obtained by knurling. In short, each of the concave-convex portions 37, 39 may have any shape as long as the ring portion 15 and the hub wheel 3 engage in the circumferential direction by biting into each other from the hub wheel 3 side and rotational power can be transmitted between them via the engaged portions.

[0056] Furthermore, in the above embodiment, the case where the recessed and projecting portions 37, 39 are provided on the ring portion 15 side has been exemplified, but it goes without saying that the recessed and projecting portions 37, 39 may also be provided on the opposing hub wheel 3 side.

[0057] Furthermore, in the above embodiment, an example was given in which one of the first uneven portion 37 and the second uneven portion 39 was provided on the ring portion 15 side, but it is of course possible to provide both uneven portions 37, 39. In this case, one of the uneven portions 37, 39 may be provided on the ring portion 15 side and the other of the uneven portions 37, 39 may be provided on the hub wheel 3 side, or both uneven portions 37, 39 may be provided on only one of the ring portion 15 and the hub wheel 3 side.

[0058] In the above description, the third serration portions 29 are provided on the outer peripheral surface 28a of the shoulder portion 28 of the outer joint member 22 so as to fit with the fourth serration portions 30 provided on the connecting member 14 (cylindrical portion 16), but the present invention is not limited to this. For example, although not shown, the third serration portions 29 may be provided on the outer peripheral surface of the cup portion 26 located radially outward of the shoulder portion 28.

[0059] In the above description, the third and fourth serration portions 29, 30 are provided at the radially opposing portions of the outer joint member 22 and the connecting member 14 (cylindrical portion 16), but other configurations are of course possible. For example, although not shown, the end face of the outer joint member 22 that axially abuts against the crimped portion 13 may be extended radially, and third serration portions may be provided at the extended portion, and fourth serration portions may be provided at the connecting member 14 (cylindrical portion 16) at a portion that axially opposes the third serration portions. In this case, the convex portions forming the shape of each serration extend radially.

[0060] DESCRIPTION OF SYMBOLS 1 Wheel bearing device 2 Outer member 3 Hub ring 4 Inner ring 5 Ball 6 Cage 7 Outer raceway surface 8 Vehicle body mounting flange 9 Wheel mounting flange 10 Inner raceway surface 11 Small diameter step portion 12 Inner member 13 Crimping portion 13a Relief portion 14 Connecting member 15 Ring portion 15a Inner diameter side end portion 16 Cylindrical portion 16a Inner peripheral surface 17 First serration portion 18 Second serration portion 19, 20 Teeth 21 Constant velocity universal joint 22 Outer joint member 23 Inner joint member 24 Cage 25 Torque transmitting ball 26 Cup portion 27 Bottom portion 28 Shoulder portion 28a Outer peripheral surface 29 Third serration portion 30 Fourth serration portion 31, 32 Teeth 33 Bolt 34 Female thread hole 35 Through hole 36 Flange portion 37, 39 Concave and recessed portions 38, 40 Plastic joint portion 41 Hub assembly

Claims

1. A hub assembly of a wheel bearing device and a constant velocity universal joint, wherein the wheel bearing device comprises an outer member, a hub ring and an inner ring arranged radially inward of the outer member, and rolling elements arranged between the outer member and the hub ring, and between the outer member and the inner ring, the inner ring is press-fitted onto the outer periphery of the hub ring from the inboard side, and an annular connecting member is fitted onto the outer periphery of the hub ring with the inner ring abutting axially on its inboard side, the inner ring and connecting member are clamped and fixed to the hub ring by plastic deformation of the inboard end of the hub ring radially outward, and the outer joint member and connecting member of the constant velocity universal joint are interconnected by a serration fit.

2. A hub assembly of a wheel bearing device and a constant velocity universal joint as described in claim 1, wherein the connecting member integrally comprises a ring portion that is fitted onto the outer periphery of the hub wheel and a cylindrical portion that extends inboard from the outer diameter side of the ring portion, and the portion of the cylindrical portion that faces radially opposite the outer joint member is connected to the outer joint member by serration fitting.

3. A hub assembly of a wheel bearing device and a constant velocity universal joint as set forth in claim 2, wherein the portion of the ring portion that faces the hub wheel in the radial direction is connected to the hub wheel by serration fitting.

4. A hub assembly of a wheel bearing device and a constant velocity universal joint as described in claim 2, wherein a relatively hard uneven portion is formed on either one of the radially opposing portions of the ring portion and the hub wheel, and the other radially opposing portion is engaged and joined to the uneven portion.

5. An assembly of a wheel bearing device and a constant velocity universal joint as described in claim 2, wherein a relatively hard uneven portion is formed on one of the portions of the ring portion and the hub wheel that face each other in the axial direction, and the other portion that faces each other in the axial direction is engaged with and joined to the uneven portion.

6. A method for assembling a hub assembly of a wheel bearing device and a constant velocity universal joint, comprising: press-fitting an inner ring onto the outer periphery of a hub wheel constituting the wheel bearing device; fitting an annular connecting member onto the outer periphery of the hub wheel; abutting the connecting member against the inner ring from the inboard side; plastically deforming the inboard end of the hub wheel radially outward to clamp and fix the inner ring and connecting member to the hub wheel; and interconnecting the outer joint member and connecting member of the constant velocity universal joint by serration fitting.

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