Drive shaft for vehicle

Abstract

In a drive shaft (101) for a vehicle, a boot attachment surface (22) which extends in an axial direction (X) and to which an inner peripheral surface of a boot (28) is attached, and a seal device attachment surface (23) which extends in the axial direction (X) and to which a seal device (37) is attached are provided on an outer periphery of an outer joint member (21) of a second constant velocity joint (20). The seal device attachment surface (23) is formed on the outer side of the joint boot attachment surface (22) in a radial direction (Y), and the boot attachment surface (22) and the seal device attachment surface (23) are connected via a vertical wall surface (24) extending along the radial direction (Y), and an outer joint member-side opening end (28a) of a boot (28) extends to the vertical wall surface (24).

Description

Vehicle drive shaft

[0001] The present disclosure relates to a drive shaft for a vehicle.

[0002] Patent Document 1 below discloses a method for manufacturing an outer joint member of a constant velocity joint. The constant velocity joint is used as a drive shaft for a vehicle. In this manufacturing method for the outer joint member, a turned material is coated with an anti-rust coating in a painting process.

[0003] Japanese Patent Application Laid-Open No. 2020-105537

[0004] The painting process requires the paint to be sprayed onto the material, which can cause concerns that workers may be affected by paint that has become airborne. Furthermore, the equipment required to collect the airborne paint is expensive. Therefore, in this type of outer joint member manufacturing method, it is desirable to eliminate the painting process altogether.

[0005] The present disclosure provides a technique that is effective in eliminating the painting process involved in the manufacture of an outer joint member that constitutes a constant velocity joint.

[0006] One aspect of the present disclosure is a vehicle drive shaft that transmits driving force generated by a drive source to wheels, the drive shaft comprising: a first constant velocity joint provided on the drive source side; a second constant velocity joint provided on the wheel side; an intermediate shaft that connects the first constant velocity joint and the second constant velocity joint so that they cannot rotate relative to each other; and a bearing that rotatably supports the second constant velocity joint with respect to a vehicle body, wherein the second constant velocity joint comprises: an outer joint member that is cylindrical with a bottom and open at one end, and has a plurality of outer guide grooves extending in the axial direction on its inner circumferential surface; an inner joint member that is housed in the outer joint member, has a plurality of inner guide grooves extending in the axial direction on its outer circumferential surface, and is connected to the intermediate shaft; a plurality of balls that are disposed in the outer guide groove and the inner guide groove; and a cylindrical boot that covers the outer periphery of the opening of the outer joint member and covers the intermediate shaft, wherein the bearing comprises: a plurality of rolling elements; an outer ring that is fixed to a vehicle body member, defines an accommodation chamber that accommodates the plurality of rolling elements, and has a plurality of raceway surfaces on its inner circumferential surface along which the plurality of rolling elements roll a seal device sealing the intermediate shaft side of the accommodating chamber, wherein the outer joint member is provided on its outer periphery with a boot attachment surface extending in the axial direction and on which the inner circumferential surface of the boot is attached, and a seal device attachment surface extending in the axial direction and on which the seal device is attached, the seal device attachment surface being formed radially outward of the boot attachment surface, the boot attachment surface and the seal device attachment surface being connected via a standing wall surface extending along the radial direction, and the outer joint member side opening end of the boot extending to the standing wall surface, or the boot attachment surface and the seal device attachment surface are cylindrical and continuously formed in the axial direction, and the outer joint member side opening end of the boot extending to the seal device.

[0007] In the vehicle drive shaft of the above aspect, the second constant velocity joint on the wheel side is connected to the first constant velocity joint on the drive source side via an intermediate shaft so as to be non-rotatable relative to the wheel side. This second constant velocity joint is rotatably supported on the vehicle body by a bearing.

[0008] In a vehicle driveshaft, a seal device mounting surface, on which a seal device is mounted, is formed radially outward of a boot mounting surface on which the inner circumferential surface of the boot is mounted. The boot mounting surface and the seal device mounting surface are connected via a vertical wall surface extending radially, and the open end of the boot facing the outer joint member extends to the vertical wall surface. In this vehicle driveshaft, the boot mounting surface and the seal device mounting surface, both of which extend axially in the outer joint member, are covered by the boot or the seal device and are not exposed to the outside, so they do not require painting. Meanwhile, the vertical wall surface connecting the boot mounting surface and the seal device mounting surface in the outer joint member extends radially. Rainwater and other water adhering to the vertical wall surface flows radially outward due to centrifugal force generated during rotation of the outer joint member, making them less likely to remain. Therefore, the vertical wall surface, like the boot mounting surface and the seal device mounting surface, does not require painting. This eliminates the painting process involved in manufacturing the outer joint member.

[0009] Alternatively, in a vehicle drive shaft, the boot mounting surface and the seal device mounting surface are cylindrical and continuously formed in the axial direction, and the open end of the boot on the outer joint member side extends to the seal device. According to this vehicle drive shaft, the boot mounting surface and the seal device mounting surface of the outer joint member, both of which extend continuously in the axial direction, are covered by the boot or the seal device and are not exposed to the outside, so they do not require painting. This eliminates the painting process required for manufacturing the outer joint member.

[0010] According to the above-described aspect, it is possible to provide a technique that is effective in eliminating the painting step involved in the manufacture of the outer joint member that constitutes the constant velocity joint.

[0011] Note that the symbols in parentheses in the claims indicate the correspondence with the specific means described in the embodiments described below, and do not limit the technical scope of the present disclosure.

[0012] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an axial cross-sectional view of a vehicle drive shaft according to a first embodiment, Fig. 2 is an axial cross-sectional view of a second constant velocity joint in Fig. 1, Fig. 3 is a cross-sectional view of a structure for eliminating a painting process of the second constant velocity joint in Fig. 2, Fig. 4 is a cross-sectional view showing a first modified example of the structure for eliminating a painting process in Fig. 3, Fig. 5 is a cross-sectional view showing a second modified example of the structure for eliminating a painting process in Fig. 3, Fig. 6 is a cross-sectional view showing a third modified example of the structure for eliminating a painting process in Fig. 3, Fig. 7 is a cross-sectional view showing a fourth modified example of the structure for eliminating a painting process in Fig. 3, Fig. 8 is a cross-sectional view showing a fifth modified example of the structure for eliminating a painting process in Fig. 3, and Fig. 9 is a cross-sectional view showing a sixth modified example of the structure for eliminating a painting process in Fig. 3.

[0013] Hereinafter, one embodiment of the vehicle drive shaft according to the above aspect will be described with reference to the drawings. In the drawings for describing this embodiment, unless otherwise specified, the axial direction along the central rotation axes L1, L2, and L3 of the vehicle drive shaft and its components is defined as the X direction, the radial direction perpendicular to the central rotation axes L1, L2, and L3 is defined as the Y direction, and the direction around the axis is defined as the D direction.

[0014] (Embodiment 1) 1. Overall Configuration of Vehicle Drive Shaft 101 The vehicle drive shaft 101 of embodiment 1 shown in Fig. 1 is a driving force transmission device that transmits driving force generated by a driving source 1 to wheels 3. This vehicle drive shaft 101 includes an input shaft 11, an intermediate shaft 19, a first constant velocity joint 10, a second constant velocity joint 20, and a bearing 30.

[0015] A rotational driving force F from a driving source 1 is input to the input shaft 11 via a differential mechanism 2. The input shaft 11 is connected to a first constant velocity joint 10 via the differential mechanism 2. In this embodiment, the driving source 1 is an electric motor. The first constant velocity joint 10 is a joint mechanism provided on the driving source 1 side. In contrast, the second constant velocity joint 20 is a joint mechanism provided on the wheel 3 side. The intermediate shaft 19 extends along the central rotation axis L2 and connects the first constant velocity joint 10 and the second constant velocity joint 20 so that they cannot rotate relative to each other around the axis. Therefore, the rotational driving force F input to the input shaft 11 is transmitted to the wheel 3 via the first constant velocity joint 10, the intermediate shaft 19, and the second constant velocity joint 20.

[0016] 2. Structure of First Constant Velocity Joint 10 As shown in Fig. 1, the first constant velocity joint 10 is an inboard joint provided on the input shaft 11 side. This first constant velocity joint 10 is what is called a tripod-type constant velocity joint. This first constant velocity joint 10 includes an outer ring 12, a tripod 13, three roller units 16, and a boot 17.

[0017] The outer ring 12 is cylindrical and has a bottom that is open at one end (right side in FIG. 1) in the axial direction along the central rotation axis L1. Three raceway grooves 12b are formed on the inner peripheral surface of the outer ring 12 at equal intervals in the circumferential direction, extending axially from the open end of the outer ring 12 toward the inner side (left side in FIG. 1).

[0018] The tripod 13 is movable in the axial direction and tiltable relative to the outer ring 12. The tripod 13 includes a boss 14 to which one end of the intermediate shaft 19 is connected, and three tripod shaft portions 15 extending radially outward from the boss 14. The outer peripheral surface of each tripod shaft portion 15 is formed in a spherical convex shape. In other words, the axial cross section of the outer peripheral surface of each tripod shaft portion 15 is formed in an arc-convex shape.

[0019] The roller unit 16 is formed in an annular shape. The roller unit 16 is rotatable on the outer periphery of each of the three tripod-shaft portions 15, slidable in the axial direction of each of the three tripod-shaft portions 15, and supported so as to be tiltable relative to each of the three tripod-shaft portions 15. Furthermore, each of the three roller units 16 is disposed so as to be rollable along each of the three raceway grooves 12b. Therefore, the three roller units 16 are configured to roll while maintaining their posture relative to the three raceway grooves 12b.

[0020] The boot 17 is tubular and covers the outer periphery of the opening 12a of the outer ring 12 and one axial end (the axial end on the left side in FIG. 1 ) of the intermediate shaft 19. The boot 17 is formed in a bellows-like shape that is axially expandable and contractible and is also bendable. The large-diameter end of the boot 17 is fastened and fixed to the outer ring 12 by an annular boot clamp 18, and the small-diameter end is fastened and fixed to the intermediate shaft 19 by an annular boot clamp 18. The boot 17 closes the opening 12a side of the outer ring 12, thereby sealing the grease contained in the internal region of the outer ring 12 to prevent leakage.

[0021] 1 , the second constant velocity joint 20 includes an outer joint member 21, an inner joint member 25, a plurality of balls 26, a cage 27, and a boot 28. The second constant velocity joint 20 is a joint of a fixed joint center type, in which the plurality of balls 26 serve as torque transmission members.

[0022] 3-1. Structure of the outer joint member 21 As shown in Fig. 1, the outer joint member 21 is a member called the outer race of the second constant velocity joint 20. The outer joint member 21 is shaped like a cylinder with a bottom that is open at one end (the left side in Fig. 1) in the axial direction along the central rotation axis L3, and has a connecting portion that is connected to the hub 39 so as to be able to transmit torque. The outer joint member 21 engages with the hub 39 by so-called "spline fitting," and is fastened and fixed to the hub 39 by bolts 6. In this way, the outer joint member 21 and the hub 39 are integrated together.

[0023] As shown in Fig. 2, the inner peripheral surface (inner surface in the radial direction Y) of the outer joint member 21 is provided with a plurality of outer guide grooves 21a extending in the axial direction X to guide the plurality of balls 26 along the axial direction X. The plurality of outer guide grooves 21a are formed at equal intervals in the circumferential direction of the outer joint member 21. Furthermore, the outer peripheral surface (outer surface in the radial direction Y) of the outer joint member 21 is provided with an inner raceway surface 21b to guide the plurality of balls 31 in the circumferential direction. The inner raceway surface 21b is formed in an annular shape in the circumferential direction of the outer joint member 21. The plurality of balls 31 roll on the inner raceway surface 21b.

[0024] In the outer joint member 21, the inner raceway surface 21b is disposed radially outward of the outer guide groove 21a so as to overlap at least a portion of the outer guide groove 21a. This results in a narrow structure in which the outer guide groove 21a and the inner raceway surface 21b are closer to each other in the axial direction X, thereby shortening the dimension of the outer joint member 21 in the axial direction X. As a result, the weight of the vehicle drive shaft 101 can be reduced.

[0025] 3-2. Structure of the Inner Joint Member 25 As shown in FIG. 1, the inner joint member 25 is connected to the intermediate shaft 19. The inner joint member 25 is annular and housed in the internal space 21d of the outer joint member 21. As shown in FIG. 2, the outer peripheral surface (the outer surface in the radial direction Y) of the inner joint member 25 is provided with a plurality of inner guide grooves 25a extending in the axial direction X to guide the plurality of balls 26 along the axial direction X. The inner joint member 25 is tiltable relative to the outer joint member 21 around a predetermined joint center point. In this embodiment, the angle between the rotational center axis L3 of the outer joint member 21 and the rotational center axis L2 of the inner joint member 25 is the joint angle. Note that FIG. 2 illustrates a state in which the joint angle is zero degrees.

[0026] 1 and 2, the plurality of balls 26 are spherical bodies of the same shape. The plurality of balls 26 are accommodated in the internal space 21d of the outer joint member 21. The plurality of balls 26 function to connect the outer joint member 21 and the inner joint member 25 so as to be able to transmit torque, and are disposed in the outer guide groove 21a of the outer joint member 21 and the inner guide groove 25a of the inner joint member 25. At this time, one ball 26 is guided by one outer guide groove 21a. The number of outer guide grooves 21a and balls 26 is six or eight.

[0027] 1 and 2, the cage 27 is formed in a cylindrical shape to hold the plurality of balls 26. The cage 27 has spherical outer and inner peripheral surfaces, and is sandwiched between an inner joint spherical surface (not shown) provided on the outer joint member 21 and an outer joint spherical surface (not shown) provided on the inner joint member 25.

[0028] 3-5. Structure of the Boot 28 As shown in Fig. 1, the boot 28 is tubular and covers the outer periphery of the opening 21c of the outer joint member 21 and the other axial end (the axial end on the right side in Fig. 1) of the intermediate shaft 19. Like the boot 17, the boot 28 is axially expandable and contractible and is formed in a bendable bellows-like cylindrical shape. The boot 28 has a large-diameter end fastened to the outer joint member 21 by an annular boot clamp 29, and a small-diameter end fastened to the intermediate shaft 19 by an annular boot clamp 29. As shown in Fig. 2, the boot 28 closes the opening 21c of the outer joint member 21, thereby sealing the grease contained in the interior region of the outer joint member 21 to prevent leakage.

[0029] 4. Structure of Bearing 30 The bearing 30 shown in Fig. 1 is for rotatably supporting the second constant velocity joint 20 relative to the vehicle body. As shown in Fig. 2, the bearing 30 is made up of multiple components including multiple balls 31, multiple balls 32, an outer ring 33, a seal device 37, and a hub 39. In the bearing 30, no separate member is interposed between the multiple balls 31 and the outer joint member 21, which is advantageous for reducing weight.

[0030] 4-1. Structure of the Outer Ring 33 The outer ring 33 shown in FIG. 2 is formed in a substantially cylindrical shape. The outer ring 33 defines a housing chamber 34 that houses a plurality of balls 31, 32. The inner peripheral surface of the outer ring 33 is provided with annular raceway surfaces 35, 36 that are formed in two rows spaced apart in the axial direction X. The raceway surface 35 is a raceway surface along which the plurality of balls 31 roll. The raceway surface 36 is a raceway surface along which the plurality of balls 32 roll. The outer ring 33 is fixed to the vehicle body member 4 with bolts (not shown). The vehicle body member 4 is, for example, a member called a "knuckle."

[0031] 4-2. Structure of the Hub 39 The hub 39 shown in FIG. 1 is formed in an annular shape. As shown in FIG. 2, the connecting portion of the outer joint member 21 is inserted into the inner periphery of the hub 39. A plurality of bolts 5 are fixed to the hub 39, and the wheels 3 serving as drive wheels are attached to the hub 39 via the bolts 5. An inner raceway 39a for guiding a plurality of balls 32 in the circumferential direction is provided on the outer peripheral surface (outer surface in the radial direction Y) of the hub 39. The inner raceway 39a is formed in an annular shape in the circumferential direction of the hub 39. The plurality of balls 32 roll on the inner raceway 39a. The inner raceway 39a is provided so as to overlap the internal space 21d of the outer joint member 21 in the radial direction Y. Forming the inner raceway 39a on the hub 39, which is integrated with the outer joint member 21, and eliminating the inner ring between the outer ring 33 and the outer joint member 21 is advantageous for reducing the size of the bearing 30.

[0032] 2, the plurality of balls 31 are spherical bodies (rolling elements) of the same shape. The plurality of balls 31 are provided between the raceway surface 35 of the outer ring 33 and the inner raceway surface 21b of the outer joint member 21. The plurality of balls 31 have the function of supporting the outer ring 33 and the outer joint member 21 so that they can rotate relatively in the direction D around the axis. The number of balls 31 can be set to an appropriate number.

[0033] 4-4. Structure of Balls 32 As shown in Fig. 2, the plurality of balls 32 are spherical bodies (rolling elements) of the same shape. The plurality of balls 32 are provided between the raceway surface 36 of the outer ring 33 and the inner raceway surface 39a of the hub 39. The plurality of balls 32 function to support the outer ring 33 and the hub 39 so that they can rotate relative to each other in the direction D around the axis (see Fig. 1). The number of balls 32 can be set to any appropriate number.

[0034] The balls 31 and 32 may be cylindrical rollers, needles, or conical tapered rollers, in addition to spheres.

[0035] 4-5. Structure of the sealing device 37 As shown in FIG. 2, the sealing device 37 is provided between the outer ring 33 and the outer joint member 21. This sealing device 37 seals the intermediate shaft 19 side of the accommodation chamber 34 defined by the outer ring 33. This sealing device 37 seals the accommodation chamber 34 of the outer ring 33 from the outside. This sealing device 37 has a known structure and is shown schematically. Note that a known magnetic encoder and sensor for detecting changes in rotation of the wheel 3 may be incorporated into this sealing device 37.

[0036] 5. Painting Process Eliminating Structure Next, with reference to FIG. 3, a painting process eliminating structure 40 for eliminating the painting process involved in manufacturing outer joint member 21 that constitutes second constant velocity joint 20 will be described.

[0037] As shown in FIG. 3 , in the painting process elimination structure 40, the end face of the sealing device 37 on the intermediate shaft 19 (see FIG. 2 ) side is positioned approximately in the radial direction Y with the outer joint member-side opening end 28a of the boot 28. In this painting process elimination structure 40, the outer joint member 21 is provided on its outer periphery with a boot mounting surface 22 extending in the axial direction X and adapted to receive the inner circumferential surface of the boot 28, and a sealing device mounting surface 23 extending in the axial direction X and adapted to mount the sealing device 37. The sealing device mounting surface 23 is formed radially outward of the boot mounting surface 22, and the boot mounting surface 22 and the sealing device mounting surface 23 are connected via a vertical wall surface 24. That is, the outer joint member 21 of this embodiment has a stepped structure in which a step is formed between the boot mounting surface 22 and the sealing device mounting surface 23. The outer joint member-side opening end 28a of the boot 28 extends to the vertical wall surface 24. As a result, the boot attachment surface 22 is covered by the inner peripheral surface of the boot 28 and is not exposed to the outside.

[0038] The standing wall surface 24 is a vertical surface extending in the radial direction Y. The standing height of the standing wall surface 24 in the radial direction Y exceeds the thickness of the end of the boot 28 on the bearing 30 side in the radial direction Y. Therefore, the standing wall surface 24 is exposed to the outside with the outer joint member side opening end 28a of the boot 28 abutting against it. Because the standing wall surface 24 is a vertical surface, rainwater and the like adhering to the standing wall surface 24 easily flows outward in the radial direction Y due to the centrifugal force generated when the outer joint member 21 rotates about the rotation central axis L3, and is less likely to remain there. Therefore, even though the standing wall surface 24 is exposed to the outside, rust is less likely to form on the standing wall surface 24.

[0039] According to the painting process elimination structure 40, the boot attachment surface 22 and the seal device attachment surface 23, both of which extend in the axial direction X, are not exposed to the outside, and the upright wall surface 24, which is exposed to the outside, is made vertical, thereby eliminating the need to paint either surface and eliminating the painting process involved in manufacturing the outer joint member 21. Furthermore, if the upright wall surface 24 is vertical, the dimension of the outer joint member 21 in the axial direction X can be shortened.

[0040] Here, the reason for forming a step between the boot-attaching surface 22 and the seal device mounting surface 23 of the outer joint member 21 in the painting process elimination structure 40 will be explained.

[0041] When heat treating the portion of the outer joint member 21 between the outer guide groove 21a and the inner raceway surface 21b, if the thickness of the portion is too thin, the hardened layer formed on the outer guide groove 21a side and the hardened layer formed on the inner raceway surface 21b side may be connected, resulting in no unhardened layer being formed between them. This raises the risk of cracks occurring during heat treatment. Therefore, it is necessary to set the outer diameter of the portion so that the portion has a certain thickness or more. On the other hand, to prevent the boot 28 from becoming too large and thereby achieve a compact outer joint member 21, it is necessary to set the outer diameter of the portion of the outer joint member 21 corresponding to the boot mounting surface 22 as small as possible. Based on these two requirements, it is preferable to form a step between the boot mounting surface 22 and the seal device mounting surface 23.

[0042] 6. Modified Examples of the Painting Process Eliminating Structure Next, modified examples of the painting process eliminating structure 40 will be described with reference to Figures 4 to 9. In these figures, the same elements as those shown in Figure 3 are designated by the same reference numerals, and the description of these same elements will be omitted.

[0043] 4, in the painting process abolishing structure 41, the end face of the sealing device 37 on the intermediate shaft 19 (see FIG. 2) side is located closer to the intermediate shaft 19 than the outer joint member side opening end 28a of the boot 28. In this painting process abolishing structure 41, compared to the painting process abolishing structure 40, the boot attachment surface 22 is formed in a position offset toward the intermediate shaft 19 with respect to the sealing device attachment surface 23, and the standing wall surface 24 connecting the boot attachment surface 22 and the sealing device attachment surface 23 is provided so as to extend along the radial direction Y. In other words, the standing wall surface 24 is an inclined surface.

[0044] Here, "extending along the radial direction Y" refers to a configuration in which the ratio of the radial component in the radial direction Y exceeds the ratio of the axial component in the axial direction X. In contrast, "extending along the axial direction X" refers to a configuration in which the ratio of the axial component in the axial direction X exceeds the ratio of the radial component in the radial direction Y. When the standing wall surface 24 extends along the radial direction Y, the angle θ between the standing wall surface 24 and a vertical plane A extending parallel to the radial direction Y is an acute angle. The vertical plane A is a plane whose normal direction is the axial direction X. When the intermediate shaft 19 side is defined as positive, the angle θ is preferably a maximum of 10°. Setting the angle θ in this manner enhances the effect of flowing rainwater and the like adhering to the standing wall surface 24 outward in the radial direction Y by the centrifugal force generated when the outer joint member 21 rotates.

[0045] According to the painting process elimination structure 41, the vertical wall surface 24 is formed as an inclined surface extending along the radial direction Y, which makes it difficult for rainwater and the like adhering to the vertical wall surface 24 to remain. Therefore, as with the painting process elimination structure 40, the painting process involved in manufacturing the outer joint member 21 can be eliminated.

[0046] As shown in FIG. 5 , in the painting process abolishing structure 42, the end face of the sealing device 37 on the intermediate shaft 19 (see FIG. 2 ) side is located on the opposite side of the intermediate shaft 19 from the outer joint member-side opening end 28a of the boot 28. In this painting process abolishing structure 42, compared to the painting process abolishing structure 40, the boot mounting surface 22 is offset from the sealing device mounting surface 23 toward the opposite side of the intermediate shaft 19, and the vertical wall surface 24 connecting the boot mounting surface 22 and the sealing device mounting surface 23 is provided so as to extend along the radial direction Y. That is, the vertical wall surface 24 is inclined. In this structure, the angle θ between the vertical wall surface 24 and the vertical plane A is preferably at least −10°. Setting this angle θ enhances the effect of flowing rainwater and other debris adhering to the vertical wall surface 24 outward in the radial direction Y by centrifugal force generated during rotation of the outer joint member 21.

[0047] According to the painting process elimination structure 42, the standing wall surface 24 is formed as an inclined surface extending along the radial direction Y, which makes it difficult for rainwater adhering to the standing wall surface 24 to remain. Therefore, as with the painting process elimination structure 40, the painting process involved in manufacturing the outer joint member 21 can be eliminated.

[0048] 6, in the painting process abolishing structure 43, a flange is provided at the end of the boot 28 on the bearing 30 side, extending outward in the radial direction Y from the boot body. This flange increases the radial dimension of the outer joint member side opening end 28a of the boot 28 in comparison with the painting process abolishing structure 40. The standing wall surface 24 connecting the boot attachment surface 22 and the seal device mounting surface 23 is blocked by the outer joint member side opening end 28a of the boot 28 so that it is not exposed to the outside when it abuts against the outer joint member side opening end 28a.

[0049] According to the painting process elimination structure 43, by devising the shape of the end of the boot 28, it is possible to prevent the upright wall surface 24 from being exposed to the outside without lowering the standing height of the upright wall surface 24 in the radial direction Y. Since the upright wall surface 24 is not exposed to the outside, the rust prevention effect of the upright wall surface 24 can be improved.

[0050] 7, in the painting process elimination structure 44, the standing wall surface 24 connecting the boot attachment surface 22 and the sealing device attachment surface 23 is provided so that its standing height in the radial direction Y is approximately the same as the thickness in the radial direction Y of the end of the boot 28 on the bearing 30 side. As a result, the standing wall surface 24 is blocked by the outer joint member side opening end 28a of the boot 28 so that it is not exposed to the outside when it abuts against the outer joint member side opening end 28a.

[0051] According to the painting process abolishment structure 44, by setting the standing height of the standing wall surface 24 in the radial direction Y low, it is possible to prevent the standing wall surface 24 from being exposed to the outside without changing the shape of the end portion of the boot 28. Since the standing wall surface 24 is not exposed to the outside, the rust prevention effect of the standing wall surface 24 can be improved.

[0052] 8, in the painting process elimination structure 45, the boot attachment surface 22 and the seal device attachment surface 23 are cylindrical and continuously formed in the axial direction X. The outer joint member side open end 28a of the boot 28 extends to the seal device 37.

[0053] According to the painting process elimination structure 45, it is possible to eliminate the portion of the outer joint member 21 that corresponds to the vertical wall surface 24.

[0054] 9 , in a painting process elimination structure 46, the bearing 30 includes an inner ring 38 that defines a housing chamber 34 between itself and the outer ring 33. When the inner ring 38 is used as a component of the outer joint member 21, the inner ring 38 is provided with an inner raceway surface 21b and a seal device mounting surface 23. In this case, the standing wall surface 24 connecting the boot mounting surface 22 and the seal device mounting surface 23 is composed of a first standing wall surface 24a formed on the outer joint member 21 and a second standing wall surface 24b formed on the inner ring 38.

[0055] According to the painting process elimination structure 46, in a structure in which the inner ring 38 is interposed between the plurality of balls 31 and the outer joint member 21, the painting process involved in manufacturing the outer joint member 21 can be eliminated.

[0056] 7. Effects According to the first embodiment, the following effects can be obtained.

[0057] In the vehicle drive shaft 101, the boot attachment surface 22 and the seal device attachment surface 23 of the outer joint member 21, both of which extend in the axial direction X, are covered with the boot 28 or the seal device 37 and therefore do not require painting. On the other hand, the standing wall surface 24 connecting the boot attachment surface 22 and the seal device attachment surface 23 of the outer joint member 21 extends along the radial direction Y. Rainwater and the like adhering to the standing wall surface 24 flows outward in the radial direction Y due to centrifugal force generated when the outer joint member 21 rotates, and is therefore unlikely to remain there. Therefore, the standing wall surface 24, like the boot attachment surface 22 and the seal device attachment surface 23, is a surface that does not require painting. This eliminates the painting process involved in the manufacture of the outer joint member 21.

[0058] Alternatively, according to the vehicle drive shaft 101, the boot attachment surface 22 and the seal device attachment surface 23 of the outer joint member 21, both of which extend continuously in the axial direction X, are covered with the boot 28 or the seal device 37, and therefore do not require painting. Therefore, the painting process involved in the production of the outer joint member 21 can be eliminated.

[0059] As described above, according to the first embodiment, the painting step involved in manufacturing the outer joint member 21 that constitutes the second constant velocity joint 20 can be eliminated.

[0060] Furthermore, by eliminating the painting process, the man-hours and time required for the subsequent inspection process can be reduced, waste materials generated due to poor painting can be eliminated, and quality against rust can be guaranteed.

[0061] 8. Modifications Although the present disclosure has been described with reference to the above-described embodiments, it is understood that the present disclosure is not limited to such embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and embodiments, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A vehicle drive shaft (101) that transmits the driving force generated by a drive source (1) to a wheel (3), comprising: - A first constant velocity joint (10) provided on the drive source side; - A second constant velocity joint (20) provided on the wheel side; - An intermediate shaft (19) that connects the first constant velocity joint and the second constant velocity joint so as not to be relatively rotatable; - A bearing (30) that rotatably supports the second constant velocity joint with respect to the vehicle body, wherein the second constant velocity joint includes: - An outer joint member (21) having a bottomed cylindrical shape with one end open and a plurality of outer guide grooves (21a) extending in the axial direction (X) on the inner peripheral surface; - An inner joint member (25) housed in the outer joint member, having a plurality of inner guide grooves (25a) extending in the axial direction (X) on the outer peripheral surface and connected to the intermediate shaft; - A plurality of balls (26) disposed in the outer guide grooves and the inner guide grooves; - A cylindrical boot (28) that covers the outer periphery of the opening (21c) of the outer joint member and covers the intermediate shaft, and the bearing includes: - A plurality of rolling elements (31, 32); - An outer ring (33) fixed to the vehicle body side member (4), partitioning an accommodation chamber (34) for accommodating the plurality of rolling elements, and having a plurality of raceways (35, 36) on the inner peripheral surface along which the plurality of rolling elements roll; - A sealing device (37) that seals the intermediate shaft side of the accommodation chamber, wherein on the outer periphery of the outer joint member, there are provided a boot attachment surface (22) extending in the axial direction (X) and having the inner peripheral surface of the boot attached thereto, and a sealing device attachment surface (23) extending in the axial direction (X) and having the sealing device mounted thereon, and the sealing device attachment surface is formed on the outer side in the radial direction (Y) of the boot attachment surface, and the boot attachment surface and the sealing device attachment surface are connected via a vertical wall surface (24) extending along the radial direction (Y), and the outer joint member side opening end (28a) of the boot extends to the vertical wall surface, or the boot attachment surface and the sealing device attachment surface are formed in a continuous cylindrical shape in the axial direction (X), and the outer joint member side opening end of the boot extends to the sealing device. A vehicle drive shaft (101).

2. The vehicle drive shaft according to claim 1, wherein a raceway surface on which the plurality of rolling elements roll is provided on an outer peripheral surface of the outer joint member, and the seal device is provided between the outer ring and the outer joint member.

3. When the boot mounting surface and the seal device mounting surface are connected via the standing wall surface, an angle (θ) formed between the standing wall surface and a vertical surface (A) extending parallel to the radial direction (Y) is in a range from -10° to 10° when the intermediate shaft side is taken as positive. The vehicle drive shaft according to claim 1 or 2.

4. The vehicle drive shaft according to claim 1 or 2, wherein the standing wall surface is exposed to the outside in a state where the outer joint member side opening end of the boot abuts.

5. The vehicle drive shaft according to claim 1 or 2, wherein the standing wall surface is blocked by the outer joint member side opening end so as not to be exposed to the outside in a state where the outer joint member side opening end of the boot abuts.

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