Constant velocity universal joint

Abstract

To provide a constant velocity universal joint with a cover member (back cover) that allows for installation without a backup ring and without the sealing material (O-ring) getting caught. [Solution] This is a constant velocity universal joint in which a cover member mounting portion is formed on the inner circumferential surface of the outer joint member. The cover member has an inner circumferential surface into which it is fitted, and has a tapered shape that widens in diameter from the inner side in the joint axial direction to the outer side in the joint axial direction. A retaining ring mounting portion for fitting a retaining ring is provided on the outer side in the joint axial direction of the outer joint member, which is further than the cover member mounting portion, and an entrance portion for guiding the cover member for fitting the cover member into the cover member mounting portion is provided on the outer side in the joint axial direction of the retaining ring mounting portion. When the minimum diameter of the entrance portion is Dc, the maximum diameter of the cover member is Db, and the outer diameter dimension of the elastic seal ring when mounted on the cover member is Da, Da

Description

Technical Field

[0001] The present invention relates to a constant velocity joint, and particularly to a constant velocity joint with a cover member (rear cover) used in a power transmission part of an industrial machine.

Background Art

[0002] In industrial machines, a common constant velocity joint is a double offset type sliding constant velocity joint as described in Patent Document 1. As an existing sliding constant velocity joint, for example, as shown in FIG. 4, an outer joint member 3 having a track groove 2 formed on an inner diameter surface 1, an inner joint member 6 having a track groove 5 formed on an outer diameter surface 4, a torque transmission ball 7 (hereinafter also simply referred to as a ball) interposed between the track groove 2 of the outer joint member 3 and the track groove 5 of the inner joint member 6, and a cage 9 that has a pocket 8 for accommodating the ball 7 and is interposed between the outer joint member 3 and the inner joint member 6.

[0003] In the illustrated example, the outer joint member 3 includes a cylindrical main body portion 10 having a track groove 2 formed on an inner diameter surface 1 and an outer flange portion 11 provided on one opening side of the main body portion 10.

[0004] By the way, in a constant velocity joint that requires high sealing performance, a cover member (rear cover) 15 is provided as shown in FIG. 4. That is, the cover member 15 includes a disk-shaped main body portion 15a, a thick portion 15b provided on the outer peripheral portion of the main body portion 15a, and a boss portion 15c provided at the center portion of the main body portion 15a. A screw hole 15c1 is provided at the axial center portion of the boss portion 15c. Also, a retaining ring 16 is disposed on the joint opening side of the cover member 15.

[0005] Furthermore, as shown in Figure 5, an O-ring 17 is provided on the outer diameter side of the thickened portion 15b of the lid member 15. That is, a circumferential groove 18 (circumferential groove of the lid member 15) is provided on the outer diameter surface 15b1 of the thickened portion 15b of the lid member 15, and the O-ring 17 is fitted into this circumferential groove 18. In this case, with the O-ring 17 fitted into the circumferential groove 18, the lid member 15 is fitted into the opening of the outer joint member 3.

[0006] Therefore, as shown in Figure 5, a tapered chamfer 20 is formed at the opening end of the opening of the outer joint member 3, which widens in diameter from the inside of the joint towards the opening of the joint, and the O-ring is fitted through this chamfer 20. The chamfer angle θ of this chamfer 20 is set to approximately 15° to 20°. The chamfer angle is specified in section 6, "Precautions concerning the installation of O-rings," of JIS B 2401-2:2012, specifically in section 6, "Chamfer of the mounting part." Specifically, it states that "When assembling equipment, it is necessary to chamfer the end or hole according to the thickness of the O-ring in order to avoid damaging the O-ring." Also, as shown in Figure 5, the maximum outer diameter D1 of the O-ring 17 before the cover member 15 is fitted is smaller in diameter than the outer end diameter dimension D2 of the chamfer 20 (maximum outer diameter of the chamfer 20), and larger in diameter than the inner end of the chamfer 20 on the inside side of the joint. The chamfer size (width dimension, axial length) Z is typically around 1.2 mm to 3.0 mm, but this varies depending on the O-ring thickness.

[0007] Therefore, the lid member 15 can be fitted into the opening of the outer joint member 3 via the chamfer 20 without getting caught on the chamfer 20. In this case, the O-ring 17 is compressed radially, and the compression allowance is set to 8-30%. The reason for providing this compression allowance is to prevent damage to the O-ring due to tearing, galling, or pinching during assembly (fitting) and to prevent deterioration of assembly performance due to increased rubber reaction force.

[0008] Furthermore, as shown in Figure 4, the retaining ring 16 has a circumferential groove 21 provided on the cylindrical surface between the lid member 15 and the chamfer 20, and the retaining ring 16 is fitted into this circumferential groove 21. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2019-120388 [Overview of the project] [Problems that the invention aims to solve]

[0010] As described above, when the cover member 15 is provided, the retaining ring 16 will be used. As shown in Figure 4, a circumferential groove 21 (circumferential groove of the outer joint member 3) into which the retaining ring 16 fits will be provided near the cover member mounting portion of the outer joint member 3. If such a circumferential groove 21 is provided, when the O-ring 17 is inserted (fitted) improperly, it may get stuck when trying to overcome the circumferential groove 21, making insertion difficult and potentially worsening work efficiency.

[0011] Furthermore, as shown in Figures 6(b) and 6(c), a backup ring 27 made of polytetrafluoroethylene resin or the like may be placed in the circumferential groove 26 into which the O-ring 25 is fitted, in order to prevent tearing or damage to the O-ring 25. As shown in Figure 6(a), if there is no backup ring 27, if pressure is applied from the direction of the arrow, a part of the O-ring 25 may protrude into the gap S between the mounting surface 28 on the side into which the O-ring 25 is fitted and the corresponding surface 29 on the mating side.

[0012] In contrast, as shown in Figure 6(b), if a backup ring 27 is placed on the protruding side, the backup ring 27 can prevent (restrict, block) the O-ring 25 from protruding. Also, in Figure 6(c), the O-ring 25 is sandwiched between a pair of backup rings 27, 27. In this case, the backup ring 27A on the pressure-applying side receives the pressure, and the backup ring 27B on the non-pressure-applying side supports the O-ring 25. This prevents deformation of the O-ring 25 and prevents (restricts, blocks) the O-ring 25 from protruding.

[0013] The backup ring 27 can be shaped in various ways, including an endless type as shown in Figure 7, a bias-cut type as shown in Figure 8, and a spiral type as shown in Figure 9.

[0014] Thus, when using a backup ring 27, the number of parts increases, and it becomes necessary to select one that corresponds to the circumferential groove 26 to which it will be mounted. This results in higher costs and poorer assembly.

[0015] Therefore, the present invention provides a constant velocity universal joint with a cover member (back cover) that does not have a gap in which a part of the seal ring protrudes even when pressure is applied, without a backup ring, and that can be installed without the seal material (O-ring) getting caught, thereby improving ease of assembly. [Means for solving the problem]

[0016] The constant velocity joint of the present invention includes an outer joint member, an inner joint member, and a torque transmission member interposed between the outer joint member and the inner joint member. It is a constant velocity joint in which a lid member installation portion is formed on the inner peripheral surface of the outer joint member that is closed by a lid member. The lid member has an outer peripheral surface that fits into the lid member installation portion. The outer peripheral surfaces of the lid member installation portion and the lid member are tapered so as to increase in diameter from the inner side in the joint axis direction toward the outer side in the joint axis direction. A retaining ring installation portion for fitting a retaining ring is provided on the outer side in the joint axis direction of the lid member installation portion of the outer joint member. An inlet portion for guiding the lid member for fitting the lid member into the lid member installation portion is provided on the outer side in the joint axis direction of the retaining ring installation portion. When the minimum diameter of the inlet portion is Dc, the maximum diameter of the lid member is Db, and the outer diameter dimension of the elastic seal ring in the state of being attached to the lid member is Da, Da < Db < Dc. In the state where the elastic seal ring is attached to the lid member, the lid member is installed in the lid member installation portion, a retaining ring is attached to the retaining ring installation portion, and the lid member is prevented from coming off.

[0017] According to the constant velocity joint of the present invention, by making the inner peripheral surface of the lid member installation portion and the outer peripheral surface of the lid member tapered so as to increase in diameter from the inner side in the joint axis direction toward the outer side in the joint axis direction, and Da < Db < Dc, a fitting between the tapered shapes can be achieved, and a close contact state can be obtained without providing a gap therebetween. That is, it can be made such that there is no gap where a part of the elastic seal ring protrudes.

[0018] By the way, since a retaining ring is attached between the inlet portion of the outer joint member and the lid member, it is necessary to provide a circumferential concave groove (retaining ring installation portion) for attaching the retaining ring on the inner diameter surface of the outer joint member between the inlet portion of the outer joint member and the lid member. However, since Da < Db < Dc, the elastic seal ring is less likely to get caught in the circumferential concave groove (retaining ring installation portion) for fitting the retaining ring during the operation of fitting (inserting) the lid member into the outer joint member.

[0019] It is preferable that the taper angle of the taper-shaped portion of the lid member installation portion of the outer joint member and the taper-shaped portion of the outer diameter surface of the lid member embedded in the taper-shaped portion of the lid member installation portion of the lid member with respect to the rotation axis of the outer joint member is 5° to 10°. By setting such a taper angle, the operation of fitting (inserting) the lid member into the outer joint member becomes easy. That is, when the taper angle is less than 5°, the inclination of the taper surface is too small, making it difficult to design without gaps. Conversely, when the taper angle exceeds 10°, the inclination of the taper surface is too large, making the operation of fitting (inserting) the lid member into the outer joint member difficult.

[0020] It is preferable that the inner side of the outer diameter surface of the lid member is a rounded shape portion, and the inner side in the axial direction of the inlet portion of the outer joint member is a rounded shape portion. By setting it in this way, it is possible to eliminate the catching part during the operation of fitting (inserting) the lid member into the outer joint member, and it becomes possible to improve the workability.

[0021] It is preferable that the inlet portion has a tapered shape that expands in diameter from the inner side in the joint axis direction toward the outer side in the joint axis direction. By setting it in this way, the start of the fitting (inserting) operation becomes easy.

[0022] The retaining ring may have a spring action that is elastically deformable in the axial direction. By setting it in this way, the retaining ring can stably exhibit its function as a retaining ring (anti-loosening function).

Advantages of the Invention

[0023] The present invention can be made to have no gap where a part of the elastic seal ring protrudes, and can effectively prevent the protrusion of the seal ring without arranging a backup ring, and can also effectively prevent damage to the seal ring during assembly.

Brief Description of the Drawings

[0024] [Figure 1] It is an enlarged exploded view of the main part of the constant velocity universal joint according to the present invention. [Figure 2] It is an enlarged cross-sectional view of the essential part of the constant velocity universal joint according to the present invention. [Figure 3] It is a cross-sectional view of the constant velocity universal joint according to the present invention. [Figure 4] It is a cross-sectional view of a conventional constant velocity universal joint. [Figure 5] It is an enlarged exploded view of the essential part of a conventional constant velocity universal joint. [Figure 6] The function of the backup ring is shown. (a) is a simplified enlarged view of the state without a backup ring, (b) is a simplified enlarged view of the state with one backup ring, and (c) is a simplified enlarged view of the state with two backup rings. [Figure 7] An endless backup ring is shown. (a) is a front view and (b) is a bottom view. [Figure 8] A bias cut backup ring is shown. (a) is a front view and (b) is a bottom view. [Figure 9] A spiral type backup ring is shown. (a) is a front view and (b) is a bottom view.

Embodiments for Carrying Out the Invention

[0025] Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 3. FIG. 1 is an enlarged exploded view of the essential part of the constant velocity universal joint according to the present invention, FIG. 2 is an enlarged cross-sectional view of the essential part of the constant velocity universal joint according to the present invention, and FIG. 3 is a cross-sectional view of the constant velocity universal joint according to the present invention.

[0026] The constant velocity universal joint includes an outer joint member 43 having a track groove 42 formed on its inner diameter surface 41, an inner joint member 46 having a track groove 45 formed on its outer diameter surface 44, a torque transmission ball 47 (hereinafter also simply referred to as a ball) as a torque transmission member interposed between the track groove 42 of the outer joint member 43 and the track groove 45 of the inner joint member 46, and a cage 49 that has a pocket 48 for accommodating the ball 47 and is interposed between the outer joint member 43 and the inner joint member 46.

[0027] Furthermore, the outer joint member 43 consists of a cylindrical main body portion 50 with a track groove 42 formed on its inner diameter surface 41, and an outer flange portion 51 provided on one opening side of the main body portion 50.

[0028] A circumferential groove 52 is provided on the inner diameter surface of the main body 50 of the outer joint member 43, opposite the outer flange portion. A stopper ring 53, which prevents the internal components consisting of the inner joint member 46, ball 47, cage 49, etc., from coming loose, is fitted into this circumferential groove 52. In addition, a cover member 55, which will be described later, is attached to the outer flange portion side of the inner diameter surface of the main body 50 of the outer joint member 43.

[0029] The end of the shaft 56 is inserted (fitted) into the axial hole of the inner joint member 46. In this case, a female spline 46a is formed in the axial hole of the inner joint member 46, and a male spline 56a is formed on the end of the shaft 56, so that when the end of the shaft 56 is fitted into the axial hole of the inner joint member 46, the female spline 46a and the male spline 56a engage. In addition, a circumferential groove 56a1 is formed on the axial end side of the male spline 56a of the shaft 56, and a retaining ring 57 that engages with the end face (end face on the lid member side) 46b of the inner joint member 46 is fitted into the circumferential groove 56a1. Furthermore, a circumferential groove 56a2 is also provided on the opposite end side of the male spline 56a of the shaft 56, and a retaining ring 58 that engages with the end face 46c of the inner joint member 46 on the opposite end side of the lid member is fitted into the circumferential groove 56a2.

[0030] Furthermore, a boot 60 is provided on the side of the outer joint member 43 opposite the outer flange to seal the opening on the opposite side of the outer flange. Here, the boot 60 is made of an elastic material and consists of a large-diameter portion 60a that is attached to the outer joint member 43, a small-diameter portion (not shown) that is attached to the shaft 56, and a bellows portion 60c that connects the large-diameter portion 60a and the small-diameter portion. In this case, the large-diameter portion 60a that is fitted onto the main body portion 50 of the outer joint member 43 is fixed to the main body portion 50 via a boot band 61. The small-diameter portion (not shown) is fitted onto the shaft 56 and fixed to the shaft 56 via a boot band (not shown).

[0031] Next, as shown in FIG. 3, the lid member 55 described above closes the opening on the outer flange side of the outer joint member 43, and includes a disk-shaped main body portion 55a, a thick portion 55b provided on the outer peripheral portion of the main body portion 55a, and a boss portion 55c provided at the center of the main body portion 55a. A screw hole 55c1 is provided in the axial center portion of the boss portion 55c.

[0032] In this case, as shown in FIGS. 1 and 2, the outer peripheral surface 62 of the thick portion 55b is a tapered surface T1 that expands in diameter from the inner side in the joint axis direction to the opening side in the joint axis direction (the opening side in this case is the opening side on the anti-boot side). A circumferential concave groove 63 (circumferential concave groove of the lid member 55) is provided on the outer peripheral surface 62, and an elastic sealing ring 64 such as an O-ring is fitted into the circumferential concave groove 63. In this case, the diameter dimension in the cross section of the elastic sealing ring 64 is set smaller than the width dimension of the circumferential concave groove 63. That is, when the diameter dimension in the cross section of the elastic sealing ring 64 is d and the width dimension of the circumferential concave groove 63 is h, d < h. This is set to allow this crushing because the elastic sealing ring 64 is in a crushed state (a state of being crushed) inward in the radial direction when the lid member 55 is attached to the outer joint member 43.

[0033] Also, the inner side in the joint axis direction of the outer peripheral surface 62 of the lid member 55 is formed as a rounded portion 65. The size of the radius Ra of this rounded portion 65 is, for example, set to a minimum of R0.5. A chamfer C1 is formed at the corner portion on the outer side of the joint of the outer peripheral surface 62 of the lid member 55, and chamfers C2 and C3 are formed on the outer side and the inner side in the joint axis direction of the opening of the circumferential concave groove 63. By the way, chamfering includes C chamfering, R chamfering, and thread chamfering, so any of these chamfers may be used as the chamfers C1, C2, and C3.

[0034] Incidentally, the outer joint member 43 has a cover member mounting portion 70 to which the cover member 55 is attached, and the tapered portion 70a of this cover member mounting portion 70 is also a tapered surface T2 that widens from the inner side in the joint axial direction to the opening side in the joint axial direction (in this case, the opening side is the opening side opposite the boot). In this case, tapered surface T1 and tapered surface T2 are the same inclined surface. That is, when the inclination angle of tapered surface T1 is θ1 and the inclination angle of tapered surface T2 is θ2, then θ1 = θ2. Here, "same" means that they may not be identical and may differ slightly due to design errors, manufacturing errors, assembly errors, etc. Note that the inclination angles θ1 and θ2 are inclination angles with respect to the axial direction.

[0035] Furthermore, a stepped surface 71 is formed on the tapered surface T2, which is the tapered portion 70a of the lid member installation portion 70, on the inward side in the joint axial direction. This stepped surface 71 acts as a stopper that restricts the intrusion of the lid member 55 into the inward side (towards the back of the joint) in the joint axial direction.

[0036] Furthermore, the tapered surface T2 of the outer joint member 43 is provided with an entrance portion 72 for guiding the cover member 55 into which the cover member 55 is fitted. Specifically, a tapered surface T3 is provided at the open end on the outer flange side of the outer joint member 43, and this tapered surface T3 serves as the entrance portion 72. In this case, the inner side of the entrance portion 72 in the joint axial direction is a rounded portion 73. The radius Rb of this rounded portion 73 is, for example, a minimum of R0.5. The entrance portion 72 is provided at the outer edge on the axial side of the cover member installation portion 70.

[0037] In this case, the inner circumferential surface of the outer joint member between the inlet portion 72 and the tapered portion 70a of the lid member mounting portion 70 is a cylindrical surface portion 75 for fitting a retaining ring, and as shown in Figure 3, a retaining ring 76 for receiving the lid member 55 is attached to this cylindrical surface portion 75. That is, a retaining ring mounting portion 77 (circumferential groove of the outer joint member 43) is provided on the cylindrical surface portion 75, and the retaining ring 76 is fitted into this retaining ring mounting portion 77. Incidentally, an existing snap ring that is known and in use can be used as the retaining ring 76.

[0038] Incidentally, as this constant velocity universal joint, taking the minimum diameter of the inlet portion 72 of the outer joint member 43 as Dc, the maximum diameter of the lid member 5 as Db, and as shown in FIG. 1, when the outer diameter dimension of the elastic seal ring 64 in the state where the elastic seal ring 64 is mounted in the circumferential groove 63 before being mounted on the outer joint member 43 is Da, Da < Db < Dc. Also, the inner peripheral surface of the outer joint member between the inlet portion 72 and the tapered portion 70a of the lid member installation portion 70 is such that when the inner diameter dimension of the cylindrical surface portion 75 is Dd, Dc = Dd.

[0039] Next, a method of mounting the lid member 55 with the above-described dimensional settings on the outer joint member 43 will be described. First, as shown in FIG. 1, the elastic seal ring 64 is fitted into the circumferential groove 63 of the lid member 55. The lid member 55 in this state is inserted into the outer joint member 43 through the inlet portion 72 of the outer joint member 43. In this case, the maximum outer diameter of the lid member 55 including the elastic seal ring 64 is Db. On the other hand, the maximum inner diameter on the outer joint member 43 side is Dc, Dc is larger than Db, and Dc = Dd. For this reason, the lid member 55 side can be inserted up to the tapered portion 70a of the tapered surface T2 of the outer joint member 43 without being caught by the outer joint member 43 side. The diameter of the end portion on the outer side in the joint axis direction of the tapered portion 70a of the tapered surface T2 is Dc, and this Dc is larger than the outer diameter dimension on the inner side in the joint axis direction from the circumferential groove 63 of the lid member 55. For this reason, the portion on the inner side in the joint axis direction from the circumferential groove 63 of the lid member 55 can enter without being caught by the tapered portion 70a of the tapered surface T2.

[0040] Furthermore, as the cover member 55 is advanced inward in the joint axial direction, the elastic seal ring 64 is compressed radially inward by the tapered portion 70a of the tapered surface T2, and as shown in Figure 2, the outer peripheral surface 62 of the cover member 55, which is the tapered surface T1, can be brought into close contact with the tapered portion 70a of the outer joint member 43, which is the tapered surface T2. At this time, the end face 55b1 on the inward side in the joint direction of the thick portion 55b of the cover member 55 may abut against the stepped surface 71 of the outer joint member 43 or face the stepped surface 71 with a small gap between them. In other words, there are two cases in which the tapered surface T1 and the tapered surface T2 are in close contact, restricting the movement of the lid member 55 inward in the joint axial direction, and there are two cases in which the tapered surface T1 and the tapered surface T2 are in contact or have a small gap between them, and the movement of the lid member 55 inward in the joint axial direction is restricted by the contact between the end face 55b1 of the lid member 55 and the stepped surface 71. The small gap between the tapered surface T1 and the tapered surface T2 is such that a part of the elastic seal ring 64 does not enter when the elastic seal ring 64 is compressed radially inward.

[0041] As shown in Figure 2, with the lid member 55 housed in the tapered portion 70a, which is the tapered surface T2 of the outer joint member 43, the retaining ring 76 is fitted into the retaining ring mounting portion 77. This allows, The lid member 55 is then incorporated into the outer joint member 43, and in this state, the compression allowance of the elastic seal ring 64 is 8% to 30%.

[0042] In this case, the retaining ring 76 will receive the end face 80 of the cover member 55 on the outside of the joint. Therefore, as shown in Figure 2, the end face 80 of the cover member 55 on the outside of the joint is slightly intruded into the retaining ring installation portion 77. For this reason, the retaining ring 76 is preferably a retaining ring that has a spring action that is elastically deformable in the axial direction (having a restraining effect) (for example, a spiral retaining ring). In this case, the spring action that has a restraining effect in the axial direction is an action that elastically presses the cover member 55 inward in the axial direction of the joint.

[0043] According to the constant velocity universal joint of the present invention, the tapered portion 70a of the opening and the outer peripheral surface 62 of the lid member 55 are formed as tapered surfaces T2 and T1 that expand in diameter from the inner side in the joint axis direction toward the outer side in the joint axis direction, and by setting Da < Db < Dc, the tapered surfaces are fitted to each other, and a close contact state can be achieved without providing a gap therebetween, and a gap where a part of the elastic seal ring 64 protrudes can be eliminated. Therefore, even without arranging a backup ring, the protrusion of the seal ring can be effectively prevented, the number of parts can be reduced, the cost can be reduced, and the assemblability can be improved. In particular, by setting Da < Db < Dc, there is no place (part) where the elastic seal ring 64 is caught during assembly, and damage to the seal ring 64 can be effectively prevented.

[0044] It is preferable that the taper angle θ2 of the tapered surface T2 of the opening of the outer joint member 43 and the taper angle θ1 of the tapered surface T1 of the lid member are 5° to 10°. Here, each taper angle is an angle with respect to the rotation axis of the outer joint member 43. By setting such a taper angle, the fitting (insertion) operation of the lid member 55 into the outer joint member 43 becomes easy. That is, when the taper angle is less than 5°, the inclination of the tapered surface is too small, and it is difficult to design so that there is no gap. Conversely, when the taper angle exceeds 10°, the inclination of the tapered surface is too large, and the fitting (insertion) operation of the lid member 55 into the outer joint member 43 becomes difficult.

[0045] It is preferable that the inner side in the joint axis direction of the outer peripheral surface 62 of the lid member 55 is formed as a rounded portion 65, and the inner side in the joint axis direction of the inlet portion 72 of the outer joint member 43 is formed as a rounded portion 73. By setting it in this way, it is possible to eliminate the catching part during the fitting (insertion) operation of the lid member 55 into the outer joint member 43, and it becomes possible to improve the workability.

[0046] The inlet portion 72 is preferably a tapered portion that expands in diameter from the inner side in the joint axis direction toward the outer side in the joint axis direction. By setting it in this way, the start of the fitting (insertion) operation becomes easy.

[0047] The retaining ring 76 may have a spring-like action that allows for elastic deformation in the axial direction (restraining effect). By setting it in this way, the retaining ring 76 can stably perform its function as a retaining ring (anti-loosening function).

[0048] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. The material of the elastic seal ring 64 can be nitrile rubber (NBR), fluororubber (FPM), chloroprene rubber (CR), ethylene propylene rubber (EPDM), ethylene acrylic rubber (EACM), silicone rubber (Q), etc.

[0049] The constant velocity universal joint may be a fixed type or a sliding type. Furthermore, the fixed type may be a Barfield type or an undercut-free type. Similarly, the sliding type may be a tripod-type sliding universal joint, a double-offset type, a cross-groove type, etc. [Explanation of Symbols]

[0050] 43 Outer joint member 46. ​​Inner joint member 47 Torque transmission member (torque transmission ball) 55 Lid member 62 Outer surface 64 Elastic sealing ring 65. R-shaped section 70 Lid member installation section 70a Tapered section 72 Entrance 73. Rounded section 76 Retaining ring T1 Tapered surface T2 Tapered Surface

Claims

1. A constant velocity universal joint comprising an outer joint member, an inner joint member, and a torque transmission member interposed between the outer joint member and the inner joint member, wherein a cover member installation portion is formed on the inner circumferential surface of the outer joint member which is covered by a cover member, The cover member has an outer circumferential surface that fits into the cover member mounting portion, the cover member mounting portion and the outer circumferential surface of the cover member have a tapered shape that widens in diameter from the inside in the joint axial direction to the outside in the joint axial direction, a retaining ring mounting portion for fitting a retaining ring is provided on the outside in the joint axial direction of the outer joint member, a cover member guide entrance portion for fitting the cover member into the cover member mounting portion is provided on the outside in the joint axial direction of the retaining ring mounting portion, the minimum diameter of the entrance portion is Dc, the maximum diameter of the cover member is Db, and the outer diameter dimension of the elastic seal ring when mounted on the cover member is Da, such that Da < Db < Dc, the cover member is installed on the cover member mounting portion with the elastic seal ring mounted on the cover member, a retaining ring is attached to the retaining ring mounting portion, and the cover member is prevented from coming off.

2. The constant velocity universal joint according to claim 1, characterized in that the taper angle with respect to the rotation axis of the outer joint member in the tapered shape of the cover member mounting portion of the outer joint member and the tapered shape of the outer diameter surface of the cover member is 5° to 10°.

3. The constant velocity universal joint according to claim 1, characterized in that the inner side of the outer diameter surface of the cover member in the joint axial direction is a rounded shape, and the inner side of the inlet portion of the outer joint member in the joint axial direction is a rounded shape.

4. The constant velocity universal joint according to claim 1, characterized in that the inlet portion has a tapered shape that expands in diameter from the inside side in the joint axial direction to the outside side in the joint axial direction.

5. The constant velocity universal joint according to claim 1, characterized in that the retaining ring has a spring action that allows it to be elastically deformed in the axial direction.

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