JP2022156817A - Fixed-type constant velocity universal joint - Google Patents

Abstract

To provide a fixed-type constant velocity universal joint excellent in handling performance at low cost.SOLUTION: In a fixed-type constant velocity universal joint 1 having a large-diameter cylinder part 21 attached to an outside joint member 2, a small-diameter cylinder part 22 attached to a shaft member 10 which can rotate integrally with an inside joint member 3, and a boot 20 to which a bellows part 23 is integrally die-molded by a flexible material, the boot 20 has a regulation part 26 for regulating relative angular displacements of both the joint members 2, 3 to an operation angle or larger at which falls of balls 4 occur.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fixed constant velocity universal joint.

As is well known, a vehicle with a drive source such as an engine or an electric motor mounted on the chassis is equipped with a power transmission device such as a drive shaft or propeller shaft to transmit the output (torque) of the drive source to the wheels. be done. This power transmission device is a constant velocity universal joint that connects two shafts, a drive shaft and a driven shaft, and can transmit torque at a constant speed even if the two connected shafts have an operating angle (even if they are relatively angularly displaced). Prepare. Constant velocity universal joints are broadly classified into fixed type constant velocity universal joints that allow only angular displacement of two connected shafts, and sliding constant velocity universal joints that permit angular displacement and axial displacement of two connected shafts. be done.

The maximum value of the working angle (maximum working angle) required when using a fixed constant velocity universal joint (during driving of an automobile) differs depending on the application, as exemplified below.
・For front drive shafts of automobiles: 45° or more ・For rear drive shafts of automobiles: 30° or less ・For propeller shafts of automobiles: 10° or less The maximum operating angle of the joint when in use is smaller than that of fixed constant velocity universal joints for front drive shafts. For this reason, fixed constant velocity universal joints for rear drive shafts and propeller shafts generally have a shorter axial dimension (track groove length) than fixed constant velocity universal joints for front drive shafts. A small outer joint member is used.

By the way, a fixed type constant velocity universal joint includes an outer joint member and an inner joint member, a plurality of balls for transmitting torque between the joint members while allowing angular displacement of both joint members, and a pocket portion holding the balls. and a shaft member connected to the inner joint member so as to be rotatable together with the inner joint member. This fixed type constant velocity universal joint is generally assembled according to the following procedure.
(1) The inner joint member and retainer are incorporated in the inner circumference of (the cup portion of) the outer joint member.
(2) The outer joint member and the inner joint member are relatively angularly displaced, and the ball is assembled in the pocket portion of the retainer exposed to the outside of the outer joint member.
(3) Finally, the shaft member is connected to the inner joint member.

In the fixed constant velocity universal joint for the front drive shaft assembled by the above procedure, the inner joint is normally operated at an operating angle that is smaller than the operating angle at which the balls are incorporated (conversely, the operating angle at which the balls fall off). Since the shaft member connected to the member interferes with the opening side end of the outer joint member, the ball will not come off the track groove of the outer joint member and fall off during handling such as transportation or assembly to an automobile. do not have. On the other hand, in a fixed constant velocity universal joint for a rear drive shaft (or for a propeller shaft) in which a small outer joint member with a shortened axial dimension is used, the shaft member interferes with the opening side end of the outer joint member. Since the operating angle at which the ball falls off is larger than the operating angle at which the ball falls off, there is a risk that the ball will fall off during handling if no countermeasures are taken.

Therefore, for example, in Japanese Patent Application Laid-Open No. 3-113124 (Patent Document 1), the shaft member is provided with an extension portion extending to the bottom side of the outer joint member, and the extension portion and the recess provided in the bottom portion of the outer joint member are combined. A fixed constant velocity universal joint has been proposed in which the contact (interference) is made at the maximum operating angle. In addition, in Japanese Patent Application Laid-Open No. 2001-280359 (Patent Document 2), a fixed constant-velocity joint is provided integrally with a shaft member with an annular protrusion that can abut (interfere) with the opening-side end surface of the outer joint member at the maximum operating angle. Universal joints have been proposed. In these fixed type constant velocity universal joints, the amount of relative angular displacement between the outer joint member and the inner joint member (the shaft member connected to them) is regulated to be less than the maximum operating angle, so the ball does not fall off during handling. can be effectively prevented.

JP-A-3-113124 Japanese Patent Application Laid-Open No. 2001-280359

However, when the technical means of Patent Document 1 is employed, the weight of the shaft member increases as the length of the shaft member increases. concerned about fading. In addition, as in Patent Document 2, when trying to obtain a shaft member having an annular projection that can interfere with the opening side end surface of the outer joint member, machining such as cutting is performed on a rod-shaped material having a large diameter dimension (volume). There is a concern that material costs and processing costs will increase significantly because of the need.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to realize a fixed type constant velocity universal joint at low cost that can prevent the ball from falling off during handling.

The present invention, which has been devised to achieve the above object, comprises an outer joint member, an inner joint member, and a plurality of balls that transmit torque between the joint members while allowing relative angular displacement of both joint members. a retainer holding balls; a shaft member provided so as to be rotatable integrally with the inner joint member; a large-diameter cylindrical portion attached to the outer peripheral surface of the outer joint member; a cylindrical portion, and a bellows portion provided between the large-diameter cylindrical portion and the small-diameter cylindrical portion that elastically expands, contracts, and bends as the joint members are displaced relative to each other; , and a boot in which the small-diameter cylindrical portion and the bellows portion are integrally molded from a flexible material, the boot is provided with both joint members relative to each other at an operating angle greater than the operating angle at which the ball falls off. and a regulating portion for regulating angular displacement. The term "flexible material" as used in the present invention refers to, for example, a resin material containing a thermoplastic elastomer as a main component, or a rubber material containing rubber as a main component. A material that can

In this manner, the boot, which is molded (cylindrically) from a flexible material, is provided with a restricting portion that restricts the relative angular displacement of the two joint members beyond the operating angle at which the ball falls off. If so, it is possible to achieve the desired displacement control function without devising the shape of the outer joint member, the inner joint member, and the shaft member, which are generally made of materials such as steel that require time and effort to process. It is possible to stably obtain a regulating portion capable of achieving low cost. As a result, it is possible to realize a fixed type constant velocity universal joint with excellent handleability at low cost without the ball falling off during handling.

The restricting portion is formed, for example, by curing a resin material filled in an annular recess provided between the large-diameter tubular portion and the bellows portion, or by setting the annular recess provided between the large-diameter tubular portion and the bellows portion. It can be formed by fitting annular members. Since the bellows portion has a form in which troughs and peaks are alternately arranged in the axial direction, a part of the molded bellows portion can be utilized as the annular recess.

As the annular member, for example, the flexible material (the material for molding the boot) is formed in an annular form without seams (connecting portions), or a plurality of circles arranged along the circumferential direction. An annular shape formed by connecting arcuate members can be employed. Such an annular member can be easily fitted into the annular recess.

When the restricting portion is formed by fitting the annular member into the annular recess of the boot, it is preferable that the cross-sectional shape of the annular member matches the cross-sectional shape of the annular recess. In this way, compared to the case where the cross-sectional shapes of the annular recess and the annular member do not match, the rigidity of the restricting portion can be increased, which is advantageous in appropriately exhibiting the desired displacement restricting function.

In the above configuration, the restricting portion can be provided with an abutting surface that abuts (engages) with the outer joint member in the axial direction. With this configuration, the restricting portion of the boot is axially supported by the outer joint member, so that the posture of the restricting portion is stabilized. Therefore, it is advantageous in stably exhibiting the desired displacement control function.

As described above, according to the present invention, it is possible to realize a fixed type constant velocity universal joint at low cost, which is excellent in handleability and in which the balls are unlikely to fall off during handling.

1 is a longitudinal sectional view of a fixed constant velocity universal joint according to an embodiment of the present invention; FIG. 1. It is a figure for demonstrating the assembly method of the fixed type constant velocity universal joint shown in FIG. 2 is a cross-sectional view showing a state in which the fixed type constant velocity universal joint shown in FIG. 1 has an operating angle; FIG. FIG. 5 is a vertical cross-sectional view of a fixed constant velocity universal joint according to another embodiment of the present invention; FIG. 5 is a vertical cross-sectional view of a fixed constant velocity universal joint according to another embodiment of the present invention; 6 is a cross-sectional view showing a state in which the fixed type constant velocity universal joint shown in FIG. 5 has an operating angle; FIG. FIG. 5 is a vertical cross-sectional view of a fixed constant velocity universal joint according to another embodiment of the present invention; (a) is a cross-sectional view taken along line PP of FIG. 7, and (b) is a view of PP of FIG. 7 when an annular member different from the annular member shown in FIG. 7 (a) is used. It is a line arrow sectional view.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings (FIGS. 1 to 8).

FIG. 1 shows a vertical cross-sectional view (partial vertical cross-sectional view) of a fixed type constant velocity universal joint 1 according to one embodiment of the present invention. The fixed constant velocity universal joint 1 is arranged along the vehicle width direction in order to transmit the output (torque) of a drive source such as an engine or an electric motor mounted on the chassis of the vehicle to the rear wheels. It is used as a constituent element of the drive shaft (rear drive shaft) that is mounted on the rear drive shaft, and is arranged at the outer (wheel side) end of the rear drive shaft in the vehicle width direction. The rear drive shaft has a sliding constant velocity universal joint (not shown) arranged at the inner end in the vehicle width direction of the automobile, a fixed constant velocity universal joint 1, and both constant velocity universal joints so that torque can be transmitted. and a connected shaft member 10 . Note that the fixed type constant velocity universal joint 1 is also simply referred to as the "constant velocity universal joint 1" below.

A constant velocity universal joint 1 shown in FIG. 1 transmits torque between an outer joint member 2 and an inner joint member 3, and between the joint members 2 and 3 while allowing relative angular displacement of the joint members 2 and 3. a retainer 5 holding the balls 4; and the shaft member 10 connected to the inner joint member 3 so as to rotate integrally therewith.

The outer joint member 2 integrally has a bowl-shaped cup portion with a bottom and a shaft portion extending axially outward from the bottom portion of the cup portion. A plurality of corresponding track grooves 2b are formed at equal intervals in the circumferential direction. The outer joint member 2 is made of, for example, a steel material having a carbon content of 0.20 to 0.45% by mass, such as carbon steel or alloy steel. A hardened layer (not shown) formed by heat treatment is formed in a portion where high mechanical strength is required, such as the surface layer of the side.

The inner joint member 3 is made of the same kind of steel as the outer joint member 2 and is formed in an annular shape, and is arranged on the inner circumference of the cup portion of the outer joint member 2 . A plurality of track grooves 3b corresponding to the number of balls 4 are formed on the spherical outer peripheral surface 3a of the inner joint member 3 at regular intervals in the circumferential direction.

The plurality of balls 4 are interposed between the paired track grooves 2 b and 3 b and transmit torque between the outer joint member 2 and the inner joint member 3 . The number of balls 4 is generally six or eight, but may be ten or twelve.

The retainer 5 is annularly formed of a metal or resin material and arranged between the spherical inner peripheral surface 2 a of the outer joint member 2 and the spherical outer peripheral surface 3 a of the inner joint member 3 . The retainer 5 has a plurality of pocket portions 5a opening on its spherical outer peripheral surface and spherical inner peripheral surface at equal intervals in the circumferential direction.

A female spline 3c is formed on the inner peripheral surface (inner wall surface of the shaft hole) of the inner joint member 3, and a male spline 10a formed on the outer peripheral surface of one end of the shaft member 10 is fitted to the female spline 3c. . As a result, the inner joint member 3 and the shaft member 10 rotate together. An annular groove 10b is formed in the shaft member 10, and a snap ring 11 fitted in the annular groove 10b is engaged with the inner joint member 3 in the direction in which the shaft member 10 is removed. Thereby, the shaft member 10 is prevented from slipping off from the inner joint member 3 . For the shaft member 10, for example, a hollow shaft or a solid shaft formed of the same steel material as the outer joint member 2 is used, and at least the portion where the male spline 10a is formed is hardened by heat treatment (not shown). ) is formed.

Although not shown, the internal space of the constant velocity universal joint 1 (the cup portion of the outer joint member 2) is filled with a lubricant such as grease. A cylindrical boot 20 is attached between the outer joint member 2 and the shaft member 10 in order to prevent lubricant from leaking to the outside and foreign matter from entering from the outside of the joint.

The boot 20 of the present embodiment is a so-called resin boot that is cylindrically molded using a resin material containing a thermoplastic elastomer as a main component. a small diameter tubular portion 22 fixed to the outer peripheral surface of the shaft member 10 using the boot band 13; and a bellows portion interposed between the large diameter tubular portion 21 and the small diameter tubular portion 22. 23 integrally. The bellows portion 23 is formed by alternately arranging the trough portions 24 and the peak portions 25 in the axial direction, and the inner joint member 3 (the shaft member 10 connected thereto) is arranged relative to the outer joint member 2. When the operating angle is given to the constant velocity universal joint 1 by the angular displacement, the constant velocity universal joint 1 elastically expands, contracts and bends.

As the thermoplastic elastomer, various requirements such as heat resistance, oil resistance and bending durability are selected from known thermoplastic elastomers such as polyester, polyurethane, polyolefin, polyamide, polystyrene, and fluorine. A material that satisfies the characteristics is selected and used. Further, as long as the boot 20 having a predetermined shape can be obtained, there is no restriction on the molding method of the boot 20, and injection molding can be adopted in addition to various known blow molding such as injection blow molding, press blow molding, and direct blow molding. is also possible. The illustrated boot 20 is formed by combining blow molding and injection molding.

When an operating angle is given to the constant velocity universal joint 1 having the above configuration, the ball 4 held in (the pocket portion 5a of) the retainer 5 moves at an angle (operating angle ) is always guided on the plane that bisects Thereby, torque is transmitted between the outer joint member 2 and the inner joint member 3 at a constant speed.

By the way, the fixed constant velocity universal joint for the front drive shaft that transmits the torque of the drive source to the front wheels, which are the steered wheels, must be able to take an operating angle of 45° or more during use (during driving). In contrast, the constant velocity universal joint 1 of the present embodiment, which is for a rear drive shaft, only needs to have an operating angle of about 20° during use. That is, the maximum operating angle θ _MAX when using the fixed constant velocity universal joint for the front drive shaft is 45° or more (for example, 47°), whereas when using the constant velocity universal joint 1 of the present embodiment, Since the maximum operating angle θ _MAX is about 20°, the portion of the track groove 2b of the outer joint member 2 that is formed on the opening side of the cup portion, which is required to obtain an operating angle exceeding 20°, It is unnecessary in the constant velocity universal joint 1 of this embodiment. Therefore, the outer joint member 2 is used in which the groove length of the track groove 2b, that is, the axial dimension, is shorter than that of the fixed constant velocity universal joint for the front drive shaft.

On the other hand, when _assembling the constant velocity universal joint 1, as shown in FIG. , the pocket portion 5a of the retainer 5 is exposed to the outside of the cup portion of the outer joint member 2, and the balls 4 are accommodated in the exposed pocket portion 5a. A ball 4 is incorporated between them (between the pair of track grooves 2b and 3b). In FIG. 2, the working angle (ball _- mounting angle) θA when the ball 4 is mounted is set to 45°. After the ball 4 is assembled between the joint members 2 and 3, the shaft member 10 is connected to the inner joint member 3, and the large-diameter tubular portion 21 and the small-diameter tubular portion 22 of the boot 20 are respectively connected to the boot. It is attached to the outer peripheral surfaces of the outer joint member 2 and the shaft member 10 using the bands 12 and 13 .

When handling the constant velocity universal joint 1 assembled by the above procedure (during transportation, assembly to a vehicle, etc.), the outer joint member 2, the inner joint member 3 to which the shaft member 10 is connected, and the plurality of balls 4 And the retainer 5 is in a state in which it can be freely displaced and moved by its own weight or the like. Therefore, if no measures are taken, even if the constant velocity universal joint 1 has a maximum working angle θ _MAX of 20° or less during use, the working angle will exceed the ball built-in angle θ _A. , the ball 4 may come off the track groove 2b of the outer joint member 2 and fall off.

Therefore, in the constant velocity universal joint 1 of the present embodiment, the boot 20 is devised to prevent the ball 4 from falling off, which may occur particularly during handling. Specifically, as shown in FIGS. 1 and 3, the outer joint member 2 and the inner joint member 3 are positioned relative to each other at an operating angle at which the ball 4 falls off (=the above-described “ball included angle θ _A ”) or more. A restricting portion 26 that restricts angular displacement is provided in the boot 20 (more specifically, between the large-diameter cylindrical portion 21 and the bellows portion 23 that constitute the boot 20).

In FIG. 3, the outer joint member 2 and the inner joint member 3 have an operating angle that is larger than the maximum operating angle θ _MAX (≈20°) in use and smaller than the ball built-in angle θ _A (=45°). Specifically, when the operating angle between the joint members 2 and 3 reaches 35°, the ball 4 (specifically, the ball 4 arranged on the extension deformation side of the bellows portion 23) is regulated. In addition to interfering with the portion 26, the shaft member 10 interferes with the restricting portion 26 via the bellows portion 23 (compressively deformed bellows portion 23). is exemplified in the case of regulating the relative angular displacement of .

If the ball 4 interferes with the restricting portion 26, or if the shaft member 10 interferes with the restricting portion 26 via the bellows portion 23, the joint members 2, 3 may be moved beyond the operating angle at which the ball 4 falls off. may be restricted from relative angular displacement. That is, as illustrated in FIG. 3, the ball 4 and the shaft member 10 may interfere with the restricting portion 26 of the boot 20 at the same time (substantially simultaneously). The member 10 may preferentially interfere. In either case, the relative angular displacement of the joint members 2 and 3 beyond the operating angle at which the ball 4 falls off is regulated. The same applies to other embodiments described later.

The regulating portion 26 of the present embodiment is formed by filling a resin material into an annular recess molded in the boot 20 and curing the resin material. Here, the resin material is filled in the valley portion 24 (first valley portion 24a) located closest to the large-diameter tubular portion 21 among the bellows portion 23 having a plurality of molded valley portions 24 and peak portions 25. The restricting portion 26 is formed by pressing and hardening. Therefore, the restricting portion 26 of the present embodiment is composed of the first valley portion 24a as an annular concave portion and the resin portion 27 hardened in the first valley portion 24a. In this case, the restricting portion 26 has higher rigidity than the bellows portion 23, and the amount of deformation when the joint members 2 and 3 are angularly displaced is much smaller than that of the bellows portion 23.

As described above, in the constant velocity universal joint 1 of the present embodiment, the tubular boot 20 made of a so-called resin boot allows both the joint members 2 and 3 to be relatively angularly displaced beyond the operating angle at which the ball 4 falls off. A regulating portion 26 for regulating the movement is provided. In this case, the desired displacement control function can be achieved without devising the shape of the steel outer joint member 2, the inner joint member 3, and the shaft member 10, which are much more laborious to process than the resin boot 20. It is possible to stably obtain the restricting portion 26 that can fulfill the requirements. Therefore, the balls 4 do not drop out of (the track grooves 2a of) the outer joint member 2 during handling, and the constant velocity universal joint 1 excellent in handleability can be realized at low cost.

The resin portion 27 constituting the restricting portion 26 can be formed using, for example, a resin material for molding the boot 20 (here, a resin material containing a thermoplastic elastomer as a main component), or a resin material for molding the boot 20. It can also be formed using a resin material different from the resin material. Examples of the above-mentioned "different resin material" include those mainly composed of a thermoplastic elastomer different from the thermoplastic elastomer used for molding the boot 20, and plastomers (which do not have elasticity at room temperature and have plastic properties). ) can be used as a main component, and it is particularly preferable to use a resin material having a higher elastic modulus than the resin material for molding the boot 20 . As a result, the rigidity of the restricting portion 26 can be increased, so that the desired angular displacement restricting function can be exhibited appropriately.

In this embodiment, the restricting portion 26 is composed of the first valley portion 24a, which is a part of the boot 20, and the resin portion 27 hardened in the first valley portion 24a. In the case of molding, the entire restricting portion 26 can be molded integrally with the large-diameter cylindrical portion 21 and the bellows portion 23 .

The restricting portion 26 to be provided on the boot 20 can also be configured as follows.

For example, as shown in FIG. 4, the restricting portion 26 of the boot 20 may be provided with an abutment surface 28 that abuts (engages) with the opening-side end surface of the outer joint member 2 in the axial direction. With this configuration, the restricting portion 26 of the boot 20 is axially supported by the outer joint member 2, so that the posture of the restricting portion 26 is stabilized. As a result, it becomes possible to exhibit the desired displacement control function more stably. This configuration can also be applied to a fixed constant velocity universal joint 1 according to another embodiment, which will be described later.

Also, as shown in FIG. 5, the restricting portion 26 is an annular concave portion molded in the boot 20 (here, as in the above-described embodiment, the large-diameter cylindrical portion 21 of the molded bellows portion 23 is provided). It can also be formed by fitting (fitting in close contact with) an annular member 29 having higher rigidity than (the bellows portion 23 of) the boot 20 to the first trough portion 24a) at the closest position.

Even when the restricting portion 26 having such a configuration is adopted, as shown in FIG. 6, it is possible to restrict the relative angular displacement of the joint members 2 and 3 beyond the operating angle at which the ball 4 falls off. can.

When the restricting portion 26 is formed by fitting an annular member into the annular recess (as the first valley portion 24a) molded in the boot 20, as shown in FIG. Preferably, an annular member 30 having a matching cross-sectional shape is employed. In this way, compared to the case where the annular member 29 having a cross-sectional shape different from the cross-sectional shape of the annular recess (see FIGS. 5 and 6) is employed, the rigidity of the restricting portion 26 can be increased. This is advantageous in appropriately exhibiting the displacement control function.

As shown in FIG. 8A, the annular member 30 is made of a thermoplastic elastomer or a flexible material containing rubber as a main component, and is formed into a seamless annular shape. Alternatively, as shown in FIG. 8(b), a plurality (in the illustrated example, 2) arc-shaped members 31 may be connected to form an annular shape. Although illustration is omitted, the same applies to the annular member 29 shown in FIGS. With the annular member 30 (29) having the above configuration, for example, it can be removed from the boot 20 after the constant velocity universal joint 1 has been assembled to the automobile, so that replacement work can be easily performed.

Although the fixed type constant velocity universal joint 1 according to the embodiment of the present invention has been described above, the embodiment of the present invention is not limited to this.

For example, in the above description, of the bellows portion 23 formed on the boot 20, the first valley portion 24a that is closest to the large-diameter cylindrical portion 21 is used (the first valley portion 24a is used as an annular concave portion). However, as long as it satisfies the function required for the bellows portion 23, such as elastic expansion, contraction and bending deformation accompanying the angular displacement of the joint members 2, 3, a plurality of troughs are formed. The restriction portion 26 may be formed using the portion 24 .

In the above description, the case where the present invention is applied to the constant velocity universal joint 1 in which the boot 20 is a resin boot molded from a resin material containing a thermoplastic elastomer as a main component has been described. It can also be preferably applied to the constant velocity universal joint 1 in which a so-called rubber boot made of a rubber material is adopted as the boot 20 . However, the resin boot is more advantageous than the rubber boot in that it is lighter in weight and has better bending durability, etc., in order to realize a lightweight and highly reliable constant velocity universal joint 1 .

The present invention is by no means limited to the embodiments described above, and can be embodied in various forms without departing from the scope of the present invention. The scope of the present invention is indicated by the claims, and includes equivalent meanings and all changes within the scope of the claims.

1 fixed constant velocity universal joint 2 outer joint member 2b track groove 3 inner joint member 4 ball 5 retainer 10 shaft member 20 boot 21 large diameter tubular portion 22 small diameter tubular portion 23 bellows portion 24 valley portion 24a first valley portion (annular concave)
26 regulating portion 27 resin portion 28 contact surface 29, 30 annular member

Claims (6)

an outer joint member and an inner joint member;
a plurality of balls that transmit torque between the joint members while allowing relative angular displacement of the joint members;
a retainer holding the balls;
a shaft member provided to rotate integrally with the inner joint member;
A large-diameter tubular portion attached to the outer peripheral surface of the outer joint member, a small-diameter tubular portion attached to the outer peripheral surface of the shaft member, and a small-diameter tubular portion provided between the large-diameter tubular portion and the small-diameter tubular portion, both joint members has a bellows portion that elastically expands, contracts, bends, and deforms with relative angular displacement, and the large-diameter tubular portion, the small-diameter tubular portion, and the bellows portion are molded integrally with a flexible material. boots and
In a fixed constant velocity universal joint with
A fixed constant velocity universal joint, wherein the boot is provided with a regulating portion for regulating relative angular displacement of both joint members beyond an operating angle at which the ball falls off. 2. The fixed constant velocity universal joint according to claim 1, wherein the restricting portion is formed by curing a resin material filled in an annular recess provided between the large-diameter cylindrical portion and the bellows portion. 2. The fixed constant velocity universal joint according to claim 1, wherein the restricting portion is formed by fitting an annular member into an annular recess provided between the large-diameter tubular portion and the bellows portion. 4. The fixed constant velocity universal joint according to claim 3, wherein said annular member is detachably fitted into said annular recess. 5. The fixed type constant velocity universal joint according to claim 3, wherein the cross-sectional shape of the annular member and the cross-sectional shape of the annular concave portion match each other. The fixed type constant velocity universal joint according to any one of claims 1 to 5, wherein the restricting portion has an abutting surface axially abutting against the outer joint member.

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