Hub assembly

Abstract

The present invention provides a hub assembly for a wheel bearing device and a constant velocity universal joint that enables power transmission via a spline fitting structure at the axial butt joint without compromising workability. [Solution] This hub assembly 41 connects a wheel bearing device 1 and a constant velocity universal joint 21 via a threaded member 44 having male threaded portions 42 and 43 at both ends. With the threaded member 44 inserted through a through hole 16 that penetrates the inner member 12 in the axial direction, one male threaded portion 42 is screwed into a female threaded hole 46 provided in the bottom portion 27 of the outer joint member 22, and a nut 45 is attached to the other male threaded portion 43 so as to sandwich and tighten the inner member 12 between the nut 45 and the outer joint member 22.

Description

Technical Field

[0003]

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

Background Art

[0002] For example, a power transmission device that transmits engine power to wheels in an automobile or the like transmits power from the engine to the wheels, and in addition to angular displacement and axial displacement due to vehicle bounce during running, allows angular displacement for vehicle turning. Therefore, generally, a drive shaft of an automobile or the like has a sliding constant velocity joint capable of coping with angular displacement and axial displacement on the differential side (inboard side), and a fixed constant velocity joint capable of taking a large operating angle on the drive wheel side (outboard side), and has a structure in which both constant velocity joints are connected by a shaft. Further, the constant velocity joint (fixed constant velocity joint) on the drive wheel side is connected to a wheel bearing device that rotatably supports the drive wheel.

[0003] As the above-described power transmission structure between the wheel bearing device and the constant velocity joint, a spline fitting structure between the outer ring stem portion of the constant velocity joint and the hub ring of the wheel bearing device is common (for example, refer to Patent Document 1). Recently, however, face spline portions that fit into each other in the axial direction are formed on the axial end face of the hub ring and the axial end face of the outer ring of the constant velocity joint that abuts against this axial end face, and teeth constituting these face spline portions fit into each other (mesh) to achieve power transmission between the wheel bearing device and the constant velocity joint. A structure has also been proposed. In this case, the hub ring and the outer ring are fixed to each other, for example, by screwing the tip of a bolt inserted through the inner circumference of the hub ring into a female screw hole provided at the bottom of the outer ring and tightening the hub ring with the bolt (for example, refer to Patent Document 2).

[0004] In conventional power transmission structures (spline fitting structure between the outer ring stem and the hub ring), when high torque is input from the vehicle, deformation such as twisting can cause the axial end face of the hub ring to slip against the axial end face of the outer ring of the constant velocity universal joint, which are abutting against each other in the axial direction, potentially leading to the generation of abnormal noise and vibration. In contrast, when a spline fitting structure is adopted at the axial abutment portion between the outer ring and the hub ring, even if the aforementioned deformation such as twisting occurs, the aforementioned slippage is prevented, thus suppressing the generation of abnormal noise and vibration. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-129698 [Patent Document 2] Patent No. 5556509 [Overview of the project] [Problems that the invention aims to solve]

[0006] On the other hand, the spline fitting structure for the axial butt joint described later has a problem in terms of workability during the vehicle assembly process compared to the conventional spline fitting structure. In other words, when connecting a wheel bearing device and a constant velocity universal joint in a way that enables power transmission using the conventional spline fitting structure, the spline fitting between the stem portion of the outer ring and the hub ring allows the wheel bearing device, including the hub ring, to be positioned and held by the stem portion of the outer ring. Therefore, there is no need to worry about the constant velocity universal joint falling off the hub ring (wheel bearing device), and the next step of attaching the nut can be performed. In other words, it becomes possible for the worker to attach the nut to the male thread at the tip of the stem portion and tighten and fix the hub ring without having to support the constant velocity universal joint by hand.

[0007] In contrast, when employing a spline fitting structure for the axial butt joint, even after aligning the phases of the face splines on the axial end faces of the hub ring and the outer ring and fitting them together, the operator must continue to support the constant velocity universal joint by hand while inserting the connecting bolt into the hole in the hub ring from the axial outside (inboard side), screwing the male threaded portion of the bolt into the female threaded hole at the bottom of the outer ring, and then tightening the hub ring. Therefore, adopting the latter structure may lead to a decrease in work efficiency, coupled with the increased workload.

[0008] Furthermore, the assembly process described above requires the supply of a constant velocity universal joint in an assembled state. Therefore, during axial butt fitting (spline fitting), the female threaded hole at the bottom of the outer ring had to be sealed with a removable cover to prevent the grease sealed inside the constant velocity universal joint from leaking out. This cover had to be removed when screwing the bolt into the female threaded hole. Consequently, this also increased the workload and could lead to a decrease in work efficiency.

[0009] In view of the above circumstances, this specification aims to provide a hub assembly for a wheel bearing device and a constant velocity universal joint that enables power transmission via a spline fitting structure at the axial butt joint without reducing workability. [Means for solving the problem]

[0010] The aforementioned problems are solved by a hub assembly of a wheel bearing device and a constant velocity universal joint according to the present invention. Specifically, this hub assembly is a hub assembly of a wheel bearing device and a constant velocity universal joint, characterized in that a first face spline portion provided on the axial end face of the inner member of the wheel bearing device and a second face spline portion provided on the axial end face of the outer joint member of the constant velocity universal joint facing the axial end face of the inner member are fitted together, thereby connecting the inner member and the outer joint member, and a threaded member having male threads at both ends is inserted through a through hole that penetrates the inner member axially, with one male thread being screwed into a female threaded hole provided at the bottom of the outer joint member, and a nut is attached to the other male thread so as to clamp the inner member between the nut and the outer joint member.

[0011] As described above, the hub assembly according to the present invention is provided with a threaded member having male threads at both ends, and a nut that can be attached to the male threads is provided. With one male thread screwed into the outer joint member, the nut can be attached to the other male thread, allowing the inner member to be clamped and tightened between the nut and the outer joint member. With this configuration, the butt fitting operation (spline fitting operation) between the constant velocity universal joint and the wheel bearing device can be performed with the threaded member, which is fixed to the outer joint member, inserted through the through hole of the inner member. This allows the butt fitting operation and subsequent nut attachment operation to be performed on the constant velocity universal joint in a cantilevered state, thus eliminating the need for the worker to manually support the constant velocity universal joint during the above operation and improving work efficiency. Furthermore, since the threaded member is already fixed to the outer joint member when the axial butt fitting operation is completed, the step of fixing the bolt to the outer joint member after the butt fitting operation, as in the conventional method, can be omitted. In addition, since the butt joint can be performed with the threaded member fixed to the outer joint member, there is no need to remove the cover or other part that was blocking the female threaded hole of the outer joint member after the butt joint is completed. As described above, the hub assembly according to the present invention improves the workability during the assembly process of the hub assembly and reduces the amount of work involved. Therefore, even with a configuration that includes a face spline portion at the axial butt joint, it is possible to improve the overall workability of the assembly process.

[0012] Furthermore, in the hub assembly according to the present invention, the axial central portion of the screw member may be formed to have a larger diameter than the male screw portions located at both ends of the screw member, and the axial central portion may be inserted into the through hole in a clearance fit state.

[0013] By configuring the threaded member in this way, the gap between the inner member and the threaded member can be made smaller. Therefore, the cantilevered holding ability of the constant velocity universal joint during butt jointing can be improved, leading to further improvements in workability.

[0014] Furthermore, in the hub assembly according to the present invention, a first flange portion having a larger diameter than the first male thread portion may be provided adjacent to the central end of one male thread portion.

[0015] By providing a first flange adjacent to one of the male threaded portions in this manner, the end face of the flange can be brought into contact with the bottom of the outer joint member, for example, and function as a positioning element when screwing one of the male threaded portions into the female threaded hole at the bottom. Of course, the maximum outer diameter of the first flange should be set to be smaller than the minimum inner diameter of the through hole in the inner member.

[0016] Furthermore, in the hub assembly according to the present invention, a second flange portion having a larger diameter than the other male thread portion may be provided adjacent to the central end of the other male thread portion.

[0017] By providing a second flange adjacent to the other male threaded portion in this manner, the flange can contribute to improving the cantilevered holding ability of the constant velocity universal joint when butt jointing. Furthermore, by shaping the threaded member as described later, and making it possible to use the other male threaded portion as one of the male threaded portions, the second flange can also function as a positioning element when screwing the other male threaded portion into the female threaded hole of the outer joint member.

[0018] Furthermore, in the hub assembly according to the present invention, the screw member may have a symmetrical shape with respect to the axial center position.

[0019] By configuring the screw component in this way, workers can handle it without having to worry about its orientation, thus reducing errors such as incorrect installation and further improving work efficiency.

[0020] Furthermore, in the hub assembly according to the present invention, the threaded member may have a male threaded portion along its entire axial length.

[0021] By configuring the screw component in this way, not only can workers handle it without having to worry about its orientation, as described above, but it can also be procured at a low cost. Therefore, it becomes possible to further reduce production costs, including labor costs.

[0022] Further, in the hub assembly according to the present invention, a protrusion having a shape in which the bottom portion protrudes toward the outer bottom surface side may be provided at the bottom of the outer joint member, and a female screw hole may be formed so as to axially penetrate the bottom portion including the protrusion.

[0023] By providing a protrusion at the bottom of the outer joint member and providing a female screw hole so as to penetrate the bottom portion including the protrusion in this way, the axial dimension of the female screw hole can be increased. Therefore, it is possible to ensure the fixing strength between the screw member and the outer joint member even in a limited space. Further, if the protrusion has a shape in which the bottom portion protrudes toward the outer bottom surface side, there is no risk that the protrusion will interfere with the surroundings.

[0024] Further, in the hub assembly according to the present invention, when providing a protrusion as described above, the protrusion may be fitted into one end opening of the through hole. <0>

[0025] By determining the shape of the protrusion in this way, the protrusion can function as a guide at the time of butt joint and the holding property in the cantilever state of the constant velocity universal joint can be enhanced. Therefore, it becomes possible to smoothly perform the above-described series of operations.

[0026] The solution to the above problem is also achieved by a method for assembling a hub assembly according to the present invention. That is, this assembling method is a method for assembling a hub assembly of a wheel bearing device and a constant velocity universal joint. After fastening a male screw portion provided at one end portion of a screw member to a female screw hole provided at the bottom of an outer joint member of the constant velocity universal joint, with the screw member inserted through a through hole axially penetrating an inner member of the wheel bearing device, a first face spline portion provided at an axial end face of the inner member of the wheel bearing device and a second face spline portion provided at an axial end face of the outer joint member of the constant velocity universal joint facing the axial end face of the inner member are fitted together to connect the inner member and the outer joint member to each other. Then, it is characterized in that a nut is attached to the male screw portion provided at the other end portion of the screw member, and the inner member is sandwiched between the nut and the outer joint member and tightened.

[0027] According to the assembly method of the present invention, similar to the hub assembly according to the present invention, in a state where the screw member fixed to the outer joint member is inserted into the through hole of the inner member, the mating operation (splined fitting operation) between the constant velocity joint and the wheel bearing device can be performed. Thereby, since the mating operation of the constant velocity joint in a cantilever state and, subsequently, the nut mounting operation can be performed, the labor of the operator supporting the constant velocity joint by hand during the above operations can be saved, and the workability is improved. Further, when the axial mating operation is completed, since the screw member is already fixed to the outer joint member, the step of fixing the bolt to the outer joint member after the mating operation as in the conventional case can be omitted. In addition, since the mating operation can be performed with the screw member fixed to the outer joint member, the labor of removing a lid or the like that has closed the female screw hole of the outer joint member after the mating operation is also unnecessary. As described above, according to the assembly method of the hub assembly according to the present invention, the workability during the assembly process of the hub assembly is improved, and the labor of the work itself can be reduced. Therefore, while providing a configuration in which a face spline portion is provided at the axial mating portion, it is possible to improve the workability related to the overall assembly process.

Effects of the Invention

[0028] 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 joint capable of power transmission through the splined fitting structure of the axial mating portion without causing a decrease in workability.

Brief Description of the Drawings

[0029] [Figure 1] It is a cross-sectional view of a hub assembly of a wheel bearing device and a constant velocity joint according to a first embodiment of the present invention. [Figure 2] It is a diagram for explaining the assembly process of the hub assembly shown in FIG. 1, and is a cross-sectional view showing a state immediately before mating the constant velocity joint with the wheel bearing device. [Figure 3]This is a cross-sectional view of a hub assembly comprising a wheel bearing device and a constant velocity universal joint according to a second embodiment of the present invention. [Figure 4] This is a cross-sectional view of a hub assembly comprising a wheel bearing device and a constant velocity universal joint according to a third embodiment of the present invention. [Modes for carrying out the invention]

[0030] The first embodiment of the present invention will be described below with reference to the drawings. First, the basic configuration of the wheel bearing device and the constant velocity universal joint will be described, followed by a description of the spline fitting structure, and then a detailed description of the connection structure via the threaded member.

[0031] Figure 1 shows a hub assembly 41 of a wheel bearing device 1 and a constant velocity universal joint 21. In this embodiment, the wheel bearing device 1 is unitized and is configured to be detachably attached to the unitized constant velocity universal joint 21. Here, 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 rows of outer raceway surfaces 7, 7 are formed on the inner circumference of the outer member 2, and a vehicle body mounting flange 8 for attachment to a vehicle body knuckle (not shown) is integrally formed on the outer circumference. A wheel mounting flange 9 for attaching a wheel (not shown) is integrally formed on one end of the hub ring 3, and an inner raceway surface 10 facing one of the double rows of outer raceway surfaces 7, 7 of the outer member 2 and a cylindrical small-diameter stepped portion 11 extending axially from this inner raceway surface 10 are formed on the outer circumference. An inner ring 4 is press-fitted into the small-diameter stepped portion 11, and an inner raceway surface 10 is formed on the outer circumference of the inner ring 4, opposite to the other of the double-row outer raceway surfaces 7, 7 of the outer member 2. In this case, the inner member 12 is formed by the hub ring 3 and the inner ring 4. Multiple balls 5, 5 are rotatably incorporated 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 retainer 6. The inner ring 4 is fixed in the axial direction by a crimping portion 13 formed by plastically deforming the axial end of the small-diameter stepped portion 11 of the hub ring 3 radially outward. In this case, a first face spline portion 14 is formed on the axial end face 13a of the crimping portion 13.

[0032] On the other hand, the constant velocity universal joint 21 mainly comprises an outer joint member 22, an inner joint member 23, a retainer 24, and a torque transmission ball 25. The outer joint member 22 consists of a cup portion 26 and a bottom portion 27 formed integrally with the cup portion 26. In this case, a second face spline portion 29 is formed on the axial end face 28a of the shoulder portion 28, which corresponds to the radially outer region of the bottom portion 27. This face spline portion 29 is brought into axial contact with the first face spline portion 14 formed on the axial end face 13a of the crimping portion 13 of the hub wheel 3, causing them to mesh with each other. This allows the rotational torque from the shaft 31 to be transmitted to the wheel mounting flange 9 via the constant velocity universal joint 21 and the hub wheel 3.

[0033] Here, the first face spline portion 14 is made up of multiple teeth 15 arranged in the circumferential direction as convex ridges. In this embodiment, each tooth 15 extends along the radial direction of the first face spline portion 14 (and thus of the hub wheel 3), and its cross-sectional shape is the same on any cross-section in the radial direction. The distance between adjacent teeth 15 in the circumferential direction (i.e., the circumferential dimension of the tooth root) increases as you move radially outward from the rotational axis. As an example of the specifications of the first face spline portion 14, when used in a passenger car including a four-wheel drive vehicle, the outer diameter of the first face spline portion 14 is about φ45 to 70 mm, the module of the teeth 15 is about 1 to 3 mm, and the pressure angle is in the range of about 20 to 30°. The second face spline portion 29 provided on the side of the constant velocity universal joint 21 and the multiple teeth 30 constituting this face spline portion 29 also have the same shape and specifications. Of course, the above configuration and specifications are merely examples, and the configuration and specifications can be arbitrarily set as long as they function as face spline sections 14 and 29 when fitted together.

[0034] These face spline portions 14 and 29 can be formed by various methods. For example, the first face spline portion 14 provided on the side of the wheel bearing device 1 can be formed simultaneously with the crimping portion 13 by using a rotary-mode oscillating molding machine (not shown). Of course, the method of forming the first face spline portion 14 is not limited to the rotary-mode oscillating molding described above, but can also be formed by other oscillating molding or plastic deformation. Furthermore, the first face spline portion 14 may be formed simultaneously with the crimping portion 13, or it may be formed after the crimping portion 13 has been formed.

[0035] Furthermore, the second face spline portion 29, provided on the side of the constant velocity universal joint 21, can be formed simultaneously with the shoulder portion 28 of the bottom portion 27 when the outer joint member 22 is formed by plastic deformation, although this is not shown in the figures. Of course, it is also possible to form the second face spline portion 29 on the shoulder portion 28 of the bottom portion 27 by plastic deformation after the outer joint member 22 has been manufactured. Alternatively, the second face spline portion 29 can be formed by appropriate means other than plastic deformation (for example, cutting by NC control).

[0036] Next, the structure for connecting and fixing the wheel bearing device 1 and the constant velocity universal joint 21 will be described. This connecting and fixing structure has a threaded member 44 having male threaded portions 42 and 43 at both ends, a nut 45, and a female threaded hole 46 provided in the central region of the bottom portion 27 of the outer joint member 22.

[0037] The threaded member 44 is inserted through a through hole 16 that penetrates the hub ring 3 of the inner member 12 in the axial direction. One male threaded portion 42 is screwed into a female threaded hole 46 provided in the bottom portion 27 of the outer joint member 22, and a nut 45 is attached to the other male threaded portion 43.

[0038] The nut 45 is attached by screwing it into the other male threaded portion 43, and in this state, it contacts the hub wheel 3 in the axial direction. The outer joint member 22 and the hub wheel 3 are connected in a way that allows power transmission through the fitting of the face spline portions 14 and 29, and the hub wheel 3 can be tightened by clamping it axially between the outer joint member 22 and the hub wheel 3. Therefore, in this embodiment, the axial dimensions of each male threaded portion 42, 43 and the axial dimension of the threaded member 44 are set to appropriate sizes so that the hub wheel 3 and the nut 45 contact in the axial direction when one male threaded portion 42 is screwed into the female threaded hole 46 along its entire axial length, and the nut 45 is screwed into the other male threaded portion 43 to an intermediate axial position.

[0039] Furthermore, in this case, the outer diameter dimensions of both the male threaded portion 42 and the axial central portion 48 of the threaded member 44 are set to be smaller than the minimum inner diameter dimension of the through hole 16.

[0040] In this embodiment, the screw member 44 has a symmetrical shape with respect to the axial center position. That is, the screw member 44 has a substantially constant outer diameter dimension along its entire axial length, and at least one male threaded portion 42 and the other male threaded portion 43 have positions, shapes, and dimensions that are symmetrical with respect to the axial center position of the screw member 44. Therefore, it is possible to use the screw member 44 in the opposite orientation to that shown in Figure 1, that is, to use the other male threaded portion 43 as one male threaded portion 42 and the one male threaded portion 42 as the other male threaded portion 43.

[0041] Furthermore, in this embodiment, the bottom portion 27 of the outer joint member 22 is provided with a projection 47 that protrudes from the bottom portion 27 toward its outer bottom surface (right side in Figure 1). In this case, a female screw hole 46 is formed so as to penetrate the bottom portion 27, including the projection 47, in the axial direction.

[0042] Furthermore, in this embodiment, the projection 47 has an outer surface shape that conforms to the inner surface of the other end opening of the through hole 16. In Figure 1, the inner surface of the other end opening of the through hole 16 has a shape that expands in diameter towards the other end (the constant velocity universal joint 21 side), and the outer surface of the projection 47 also has a shape that expands in diameter towards the other end.

[0043] The hub assembly 41 with the above configuration can be assembled, for example, by the following procedure.

[0044] First, the assembled (unitized) wheel bearing device 1 and constant velocity universal joint 21 are prepared, excluding the connecting and fixing structure including the threaded member 44. Then, one male threaded portion 42 of the threaded member 44 is screwed into the female threaded hole 46 provided in the bottom portion 27 of the outer joint member 22 to a predetermined axial position. After that, the wheel bearing device 1 and the constant velocity universal joint 21 are brought closer together in the axial direction, and the threaded member 44, which is connected and fixed to the outer joint member 22, is inserted into the through hole 16 of the hub wheel 3 (see Figure 2). Thus, just before the first face spline portion 14 provided on the crimping portion 13 of the hub wheel 3 and the second face spline portion 29 provided on the shoulder portion 28 of the outer joint member 22 are brought into axial contact, the situation in which one of the constant velocity universal joint 21 or the wheel bearing device 1 tilts significantly relative to the other and falls off can be prevented as much as possible by contact with the threaded member 44.

[0045] Subsequently, the first face spline portion 14 and the second face spline portion 29 are butted together and fitted, with their circumferential positions aligned. This allows rotational power to be transmitted between the wheel bearing device 1 and the constant velocity universal joint 21 via both face spline portions 14 and 29.

[0046] After achieving spline fitting in this manner, the nut 45 is screwed onto the other male threaded portion 43 of the threaded member 44, and the nut 45 is pressed against the hub wheel 3 in the axial direction, and the hub wheel 3 is tightened by sandwiching it axially between the nut 45 and the outer joint member 22. As a result, the outer joint member 22 and the hub wheel 3 are connected and fixed via the threaded member 44 and the nut 45 (as shown in Figure 1), and the assembly of the hub assembly 41 of the wheel bearing device 1 and the constant velocity universal joint 21 is completed.

[0047] As described above, in the hub assembly 41 according to this embodiment, a threaded member 44 having male threaded portions 42 and 43 at both ends is provided, and a detachable nut 45 is provided on the other male threaded portion 43. With one male threaded portion 42 screwed into the female threaded hole 46 of the outer joint member 22, the nut 45 is screwed onto the other male threaded portion 43, thereby creating a structure in which the hub wheel 3 can be tightened by sandwiching it axially between the nut 45 and the outer joint member 22. As a result, the butt fitting operation (spline fitting operation) between the constant velocity universal joint 21 and the wheel bearing device 1 can be performed with the threaded member 44, which is fixed to the outer joint member 22, inserted through the through hole 16 of the hub wheel 3. This allows the butt fitting operation, and subsequently the installation of the nut 45, to be performed with the constant velocity universal joint 21 cantilevered, thus eliminating the need for the worker to manually support the constant velocity universal joint 21 during the above operation and improving work efficiency. Furthermore, since the threaded member 44 is already fixed to the outer joint member 22 when the axial butt joint is completed, the step of fixing the bolt to the outer joint member 22 after the butt joint, as in the conventional method, can be omitted. In addition, since the butt joint can be performed with the threaded member 44 fixed to the outer joint member 22, the effort of removing the cover or the like that was blocking the female threaded hole 46 of the outer joint member 22 after the butt joint is also eliminated. As described above, the hub assembly 41 according to the present invention improves the workability during the assembly process of the hub assembly 41 and reduces the amount of work involved, so that even with a configuration that includes face spline portions 14 and 29 on the axial butt joint portion (crimp portion 13 and shoulder portion 28), it is possible to improve the overall workability of the assembly process.

[0048] Furthermore, in this embodiment, a projection 47 is provided, and a female screw hole 46 is provided that penetrates the bottom portion 27 including the projection 47. This allows for increased fixing area between the screw member 44 and the outer joint member 22 within a limited space, thereby enabling a strong connection and fixation.

[0049] Furthermore, by making the outer surface of the projection 47 conform to the shape of the inner surface on the other end opening side of the radially opposing through hole 16, the gap with the inner surface of the through hole 16 can be reduced, thereby improving the cantilevered holding ability during butt joint work.

[0050] Although the first embodiment of the present invention has been described above, the hub assembly of the wheel bearing device and constant velocity universal joint and the method of assembling the same can take other forms as long as they remain within the scope of the present invention.

[0051] For example, in the above embodiment, a screw member 44 is provided in which the outer diameter dimension is substantially constant over its entire axial range. However, of course, the screw member according to the present invention can take other forms. Figure 3 shows a cross-sectional view of a hub assembly 41 according to one example (second embodiment of the present invention). As shown in Figure 3, in the hub assembly 41 according to this embodiment, the outer diameter dimension of the axial central portion 48 of the screw member 44 is formed to be larger than the outer diameter dimensions of the male threaded portions 42 and 43 located at both ends of the screw member 44, and the screw member 44 is inserted through the through hole 16 of the hub wheel 3 such that the axial central portion 48 is in a clearance fit with respect to the through hole 16.

[0052] By providing a large-diameter portion in the threaded member 44 in this way, the gap between the hub wheel 3 and the threaded member 44 can be set to be small. Therefore, the cantilevered holding ability of the constant velocity universal joint 21 during butt jointing can be improved, and further improvements in workability can be achieved. Of course, even if a clearance fit is not achieved with respect to the through hole 16 of the hub wheel 3, a configuration in which the axial central portion 48 is formed to be larger in diameter than both ends (male threaded portions 42, 43) can still contribute to improving the holding ability of the constant velocity universal joint 21 and is therefore preferable.

[0053] Figure 4 shows a cross-sectional view of a hub assembly 41 according to yet another example (a third embodiment of the present invention). As shown in Figure 4, in the hub assembly 41 according to this embodiment, a first flange portion 49 is provided adjacent to the central end of one male thread portion 42 and has a larger diameter than the one male thread portion 42. In addition, in this embodiment, in addition to the first flange portion 49, a second flange portion 50 is provided adjacent to the central end of the other male thread portion 43 and has a larger diameter than the other male thread portion 43.

[0054] In this case, the first flange portion 49 is in surface contact with the outer bottom surface of the bottom portion 27 of the outer joint member 22, with its axial end surface in contact with it.

[0055] Furthermore, in this embodiment, the screw member 44 is configured to be symmetrical with respect to the axial center position. That is, one male threaded portion 42 and the other male threaded portion 43 are formed to have the same shape and dimensions so as to be symmetrical with respect to the axial center position of the screw member 44. Also, the first flange portion 49 and the second flange portion 50 are formed to have the same shape and dimensions so as to be symmetrical with respect to the axial center position of the screw member 44.

[0056] By providing the first flange portion 49 adjacent to one of the male threaded portions 42 in this manner, the first flange portion 49 can function as a positioning guide when screwing the male threaded portion 42 into the female threaded hole 46 of the bottom portion 27 by screwing the male threaded portion 42 until the axial end face of the first flange portion 49 contacts the outer bottom surface of the bottom portion 27 of the outer joint member 22.

[0057] Furthermore, by providing a second flange portion 50 adjacent to the other male threaded portion 43, this flange portion 50 can improve the cantilevered holding ability of the constant velocity universal joint 21 when butt jointing. Moreover, as in this embodiment, by making the threaded member 44 symmetrical with respect to the axial center position, the other male threaded portion 43 can also be used as one of the male threaded portions 42, so the threaded member 44 can be attached to the outer joint member 22 without worrying about the orientation of the threaded member 44, thereby further improving workability.

[0058] Furthermore, while the above embodiment illustrates a case where male threaded portions 42 and 43 are provided at both ends of the screw member 44, other configurations are of course possible. For example, although not shown in the illustration, it is also possible to have a configuration in which male threaded portions are provided along the entire axial direction of the screw member 44.

[0059] Furthermore, in the above embodiment, an example was given in which a projection 47 having an outer surface shape similar to the inner surface of the other end opening of the through hole 16 is provided. In this case, the projection 47 may be configured to fit into the other end opening of the through hole 16. That is, although not shown in the illustration, the outer diameter of the projection 47 may be set so that the gap with the other end opening of the through hole 16 in the configuration shown in Figure 1 becomes small enough to be, for example, a clearance fit. This further stabilizes the posture of the constant velocity universal joint 21 when butt jointing, making it possible to perform each operation more efficiently and easily.

[0060] In the above embodiment, an example was given in which the female screw hole 46 is provided so as to penetrate the bottom portion 27 of the outer joint member 22, but it is not necessary for it to penetrate all the way through. If a projection 47 is provided on the outer bottom surface side of the bottom portion 27 as shown in Figure 1, etc., although not shown in the illustration, the female screw hole 46 may be provided in a form that opens on the tip side of the projection 47 and extends to an intermediate position in the thickness direction of the bottom portion 27 of the outer joint member 22 including the projection 47. [Explanation of symbols]

[0061] 1. Wheel bearing device 2 Outer member 3 Hub wheels 4. Inner Ring 5 balls 6 Cage 7 Outer raceway surface 8. Body mounting flange 9 Wheel mounting flange 10 Inner raceway surface 11 Small diameter stepped section 12 Inner member 13 Crimping section 13a Axial end face 14 First face spline section 15 teeth 16 through holes 21. Constant velocity universal joint 22 Outer joint member 23. Inner joint member 24 Cage 25 Torque transmission ball 26 cup section 27 Bottom 28 Shoulder 28a Axial end face 29 Second face spline section 30 teeth 31 shafts 41 Hub Assembly 42, 43 Male threaded section 44 Screw component 45 nuts 46 Female threaded holes 47 Protrusion 48 Axial center 49 First guard 50 Second guard section

Claims

1. A hub assembly comprising a wheel bearing device and a constant velocity universal joint, The first face spline portion provided on the axial end face of the inner member of the wheel bearing device and the second face spline portion provided on the axial end face of the outer joint member of the constant velocity universal joint facing the axial end face of the inner member are fitted together, thereby connecting the inner member and the outer joint member. A hub assembly for a wheel bearing device and a constant velocity universal joint, wherein a threaded member having male threads at both ends is inserted through a through hole that penetrates the inner member axially, one of the male threads is screwed into a female threaded hole provided at the bottom of the outer joint member, and the nut is attached to the other male thread so as to clamp the inner member between the nut and the outer joint member.

2. The hub assembly of a wheel bearing device and a constant velocity universal joint according to claim 1, wherein the axial central portion of the screw member is formed to have a larger diameter than the male screw portions located at both ends of the screw member, and the axial central portion is inserted into the through hole in a clearance fit state.

3. A hub assembly of a wheel bearing device and a constant velocity universal joint according to claim 1, wherein a first flange portion having a larger diameter than the one male threaded portion is provided adjacent to the central end of the one male threaded portion.

4. A hub assembly of a wheel bearing device and a constant velocity universal joint according to claim 3, wherein a second flange portion having a larger diameter than the other male thread portion is provided adjacent to the central end of the other male thread portion.

5. The hub assembly of a wheel bearing device and a constant velocity universal joint according to claim 1, wherein the screw member has a symmetrical shape with respect to the axial center position.

6. The hub assembly of a wheel bearing device and a constant velocity universal joint according to claim 1, wherein the threaded member has the male threaded portion along its entire axial length.

7. A hub assembly of a wheel bearing device and a constant velocity universal joint according to claim 1, wherein the bottom of the outer joint member is provided with a projection that causes the bottom to protrude toward its outer bottom surface, and the female screw hole is formed so as to penetrate the bottom including the projection in the axial direction.

8. The hub assembly of a wheel bearing device and a constant velocity universal joint according to claim 7, wherein the projection is fitted into one end opening of the through hole.

9. A method for assembling a hub assembly of a wheel bearing device and a constant velocity universal joint, After screwing one of the male threaded portions of a threaded member having male threaded portions at both ends into the female threaded hole provided at the bottom of the outer joint member of the constant velocity universal joint, With the threaded member inserted through the through hole that penetrates the inner member of the wheel bearing device in the axial direction, the first face spline portion provided on the axial end face of the inner member of the wheel bearing device and the second face spline portion provided on the axial end face of the outer joint member of the constant velocity universal joint that faces the axial end face of the inner member are fitted together to connect the inner member and the outer joint member, A method for assembling a hub assembly of a wheel bearing device and a constant velocity universal joint, comprising attaching a nut to the other male threaded portion provided at the other end of the threaded member, and then tightening the inner member between the nut and the outer joint member.

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