WO2008018290A1 - Fixed constant velocity universal joint - Google Patents

Abstract

A fixed constant velocity universal joint capable of realizing an operating angle larger than conventional by enabling any ball to protrude from the race of the outer joint member without causing the ball to come out of the race. Even if a ball comes out of the race, the ball can return to the race by preventing the interference with the outer joint member to smoothly operate the constant velocity universal joint. The joint opening end of the race (1b) of an outer joint member (1) is used as a guide section (1d) open radially outward. This guide section (1d) can smoothly return the ball (4) which has come out of the race (1b) of the outer joint member (1) to the race (1b). Since interference between a ball (4) and the outer joint member (1) is avoided, the joint can be smoothly operated even if a large operating angle is set.

Description

 Specification

 Fixed type constant velocity universal joint

 Technical field

 [0001] The fixed type constant velocity universal joint of the present invention connects a drive-side rotating shaft and a driven-side rotating shaft so that torque can be transmitted at a constant angular velocity even when both shafts form an angle. . This fixed type constant velocity universal joint can only be angularly displaced without plunging, and is used for power transmission of various industrial machines including automobiles.

 Background art

 [0002] A fixed type constant velocity universal joint is generally used for an axle connecting portion of a drive shaft of an automobile or a bent shaft connecting portion of a steering shaft. As this fixed type constant velocity universal joint, for example, a Zepper type constant velocity universal joint is known. The zebra type constant velocity universal joint invented by Zeppa initially has the same arc centered on the joint center, both of the ball center locus of the guide groove of the outer joint member and the ball center locus force of the guide groove of the inner joint member. (See Patent Document 1).

 [0003] Zepper type constant velocity universal joints have since been improved, and the so-called double offset type is widely used! (See Patent Document 2). Double offset type constant velocity universal joints have the same radius around the center of the ball center of the two guide grooves of the outer joint member and the inner joint member, which are separated by an equal distance from the joint center in the opposite direction of the joint axial direction. It is a circle.

 [0004] In this double offset type constant velocity universal joint, when the joint is rotated at a high operating angle, if the ball protrudes outward from the guide groove of the outer joint member, the ball is radially outward from the cage window. It cannot be prevented from flying out. For this reason, in conventional double offset type constant velocity universal joints, the ball must be stored in the guide groove of the outer joint member. This limits the limit operating angle of the joint, which is at most about 48 °. It was.

[0005] On the other hand, undercut-free type (hereinafter referred to as UJ type! /, U) constant velocity universal joints, which are another type of fixed type constant velocity universal joints, are higher than Zepper type constant velocity universal joints. To make working angle It was invented. In this zepper type, the ball center locus of the guide groove of the outer joint member

1S Of the arc of the Zepper meridian, the opening side portion of the outer joint member is a straight line parallel to the joint axis from the cross section perpendicular to the axis passing through the joint center (see Patent Document 3). However, even with this UJ type constant velocity universal joint, the limit operating angle was about 52 °.

[0006] Fig. 10 shows a specific example of a double offset type constant velocity universal joint. This constant velocity universal joint has an outer joint member 1 having one end opened and a plurality of (for example, six) curved guide grooves lb formed on the spherical inner peripheral surface la in the axial direction, and a spherical outer periphery. Inner joint member 2 in which a plurality of (for example, six) curved guide grooves 2b are formed in the surface 2a in the axial direction, and a shaft inserted into one end of the inner joint member 2 (spline or selection) hole 2c. 6 and the guide groove lb of the outer joint member 1 and the guide groove 2b of the inner joint member 2 are formed in cooperation with each other, a plurality of (for example, six) ball tracks 3, and one for each ball track 3. It consists of torque transmission balls 4 arranged one by one and a cage 5 that holds the torque transmission balls ₄ . The outer peripheral spherical surface 5 a of the cage 5 is in sliding contact with the inner peripheral spherical surface 1 a of the outer joint member 1, and the inner peripheral spherical surface 5 b of the retainer 5 is in sliding contact with the outer peripheral spherical surface 2 a of the inner joint member 2. The center of curvature of the inner peripheral spherical surface la of the outer joint member 1 and the center of curvature of the outer peripheral spherical surface 2a of the inner joint member 2 both coincide with the joint center O. The center of curvature O of the guide groove lb (hereinafter referred to as the outer ring guide groove lb) of the outer joint member 1 and the center of curvature O of the guide groove 2b (hereinafter referred to as the inner ring guide groove 2b) of the inner joint member 2 are the center O of the joint. Axial direction across

 2

 The center o is on the joint opening side and the center o is on the joint.

 1 2 Arranged on the back side.

 Patent Document 1: US Pat. No. 1,665,280

 Patent Document 2: US Patent No. 2046584

 Patent Document 3: JP-A 53-65547

 Disclosure of the invention

 Problems to be solved by the invention

In the constant velocity universal joint shown in FIG. 10, the center of curvature O of the outer ring guide groove lb is closer to the joint opening side than the center of curvature O of the inner ring guide groove 2b as described above. Thus, the outer ring guide groove lb and

 2

 The center of curvature O, O of the inner ring guide groove 2b is offset in the axial direction.

 1 2

The rack 3 has a wedge shape opened toward the opening side of the outer joint member 1. For this reason, When a load is applied to the joint, a force F (indicated by an arrow in FIG. 10) is applied to the ball 4 to push the cage 5 toward the opening side of the outer joint member 1. At this time, the joint opening side region D ′ of the inner peripheral spherical surface la of the outer joint member 1 holds the cage 5 against the force F, so that the cage 5 is prevented from coming off from the outer joint member 1. .

 By the way, the limit operating angle of the constant velocity universal joint is limited by the interference between the shaft 6 and the open end 1 c of the outer joint member 1. That is, in order to increase the limit operating angle, the overhang length of the open end lc of the outer joint member 1 may be shortened, that is, the distance L between the open end lc and the joint center O may be shortened. However, when the distance L between the opening end lc of the outer joint member 1 and the joint center O is shortened, the joint opening side region D ′ where the inner circumferential spherical surface la of the outer joint member 1 holds the cage 5 against the force F is increased. Reduced. For this reason, depending on the gap width between the inner peripheral spherical surface 1a of the outer joint member 1 and the outer peripheral spherical surface of the cage 5, the outer joint member 1 cannot hold the cage 5, May cause trouble.

 [0010] Further, in order to increase the limit operating angle of the joint (for example, about 60 °), it is necessary to place the ball outside the guide groove force of the outer joint member. At that time, if the ball is taken out from the guide groove of the outer joint member without taking any measures against the constant velocity self-joint as described above, the ball may fall off. In order to prevent such problems, the present applicant proposed a constant velocity universal joint having the following configuration in the previous application.

 [0011] For example, in the constant velocity universal joint of Japanese Patent Application No. 2005-140162, the joint back side portion of the guide groove of the inner joint member is formed into an arc having the joint center as the center of curvature. As a result, even when a large operating angle is taken, the center position of the ball is not separated from the center of the joint. Therefore, even if the ball comes out of the guide groove of the outer joint member, the cage and the guide groove of the inner joint member The ball can be held between them.

 [0012] In addition, in the constant velocity universal joint of Japanese Patent Application No. 2005-162969, the outer side window opening dimension of the cage window that accommodates the ball is made smaller than the diameter of the ball. Thereby, even if it is the outer side of an outer joint member, since a ball | bowl can be held by the guide groove side of an inner joint member with a holder | retainer, it can prevent that a ball | bowl falls from a holder | retainer.

[0013] In this way, in the constant velocity universal joint that can be protruded from the guide groove of the outer joint member without dropping the ball, the outer joint member can be moved along with the rotation or bending of the joint. The ball that has come out of the guide groove is returned to the guide groove again. At this time, the ball and the open end of the outer joint member may interfere with each other, and the smooth operation of the constant velocity universal joint may be hindered.

 [0014] A first object of the present invention is to provide a fixed type constant velocity universal joint that can realize a higher operating angle than the conventional one by allowing it to protrude from the guide groove of the outer joint member without dropping the ball. This is to prevent the interference between the outer joint member and the outer joint member and to operate the constant velocity universal joint smoothly. A second object of the present invention is to securely hold a cage inside an outer joint member in a fixed type constant velocity self-joint capable of realizing a high operating angle. Means for solving the problem

 [0015] In order to solve the above-mentioned problem, the invention of claim 1 is characterized in that an outer joint member having one end opened and formed with a plurality of guide grooves extending in the axial direction on a spherical inner peripheral surface, and a spherical outer peripheral surface An inner joint member formed with a plurality of guide grooves extending in the axial direction, a plurality of ball tracks formed by cooperation of the guide groove of the outer joint member and the guide groove of the inner joint member, and each ball track In a fixed type constant velocity universal joint equipped with one torque transmission ball and one cage that holds the torque transmission ball, the joint opening side end of the guide groove of the outer joint member is radially outward. It is characterized by an open guide part.

 [0016] Since the joint opening side end portion of the guide groove of the outer joint member is a guide portion that opens radially outward, the balls that have come out from the guide groove of the outer joint member can be smoothly passed by this guide portion. It can be returned to the guide groove. For this reason, the interference between the ball and the outer joint member is avoided, and the joint can be smoothly operated even when a large operating angle is taken.

 [0017] The invention of claim 2 is characterized in that, in the invention of claim 1, the ball track has a wedge shape in which the radial interval between the opposing guide grooves is narrowed toward the opening side of the outer joint member.

[0018] When the ball track has a wedge shape narrowed toward the opening side of the outer joint member, there is a high possibility that the ball and the outer joint member interfere with each other. It is effective to provide an id part. In addition, when a load is applied to the joint, a force is applied to the ball to push the cage toward the inner side of the joint, and the cage is held in the inner area of the inner spherical surface of the outer joint member against this force. . The back region of the inner spherical surface of this outer joint member is Even if the distance between the open end of the outer joint member and the joint center is shortened in order to increase the operating angle of the joint, it will not be reduced. Therefore, even when the operating angle of the joint is increased, the cage can be securely held inside the outer joint member.

[0019] The invention of claim 3 is the invention of claim 1, wherein the region including the end portion on the joint back side of the guide groove of the inner joint member is an arc centered on the joint center, and the ball By making the outer peripheral side window opening size of the window of the cage containing the ball smaller than the diameter of the ball, it is possible to protrude from the guide groove of the outer joint member without dropping the ball. .

 [0020] By making the joint back side portion of the guide groove of the inner joint member into an arc whose center of curvature is the joint center, and the outer side window opening dimension of the cage window is smaller than the diameter of the ball, a large size is obtained. Even when the working angle is taken, the center position of the ball is not far from the center of the joint, and even if the ball goes out of the guide groove of the outer joint member, the ball is inserted between the cage and the guide groove of the inner joint member. Can be held.

 [0021] The invention of claim 4 is characterized in that, in the invention of claim 2, the guide portion has a curved shape having a center of curvature on the opening outer diameter side of the outer joint member.

 [0022] With the curvilinear guide portion, the force S smoothly returns the ball that has come out of the guide groove to the guide groove.

 [0023] The invention of claim 5 is characterized in that, in the invention of claim 2, the guide portion has a linear shape whose inner diameter continuously increases toward the opening of the outer joint member.

 [0024] With the straight guide portion, the ball S that has come out of the guide groove to the outside is smoothly returned by the force S.

 [0025] The invention of claim 6 is the invention of claim 1, wherein the ball center locus in the guide groove of the outer joint member and the inner joint member is equally offset to the opposite side in the joint axial direction across the joint center, and The center of curvature of the main arc of the ball center trajectory in the guide groove of the joint member is arranged on the deeper side of the joint than the center of curvature of the main arc of the ball center trajectory in the guide groove of the inner joint member.

[0026] Thereby, it is possible to obtain a wedge-shaped ball track in which the radial distance between the opposing guide grooves is narrowed toward the opening side of the outer joint member. [0027] The invention of claim 7 is the invention of claim 6, wherein the ball center locus in the guide groove of the inner joint member is extended from the joint back side end portion of the main arc, and the joint center is defined as the center of curvature. The outer peripheral side window opening size of the retainer window that accommodates the ball can be made smaller than the diameter of the ball so that it can protrude from the guide groove of the outer joint member without dropping the ball. It is characterized by that.

 [0028] Thereby, the overhang length of the opening end portion of the outer joint member (distance U in Fig. 10 can be shortened and the operating angle of the joint can be increased).

 [0029] The invention of claim 8 is the same as that of claim 7, and the curvature center of the main arc of the ball center locus in the guide groove of the outer joint member and the inner joint member is It is characterized by being offset equally in the direction of increasing the diameter.

 [0030] Thereby, since the groove depth of the guide groove of the outer joint member becomes deeper, it is possible to more reliably prevent the ball from climbing up due to torque load. Further, the length of the guide groove of the outer joint member can be extended by the offset. Furthermore, the surface pressure received from the ball by the guide groove of the inner joint member can be reduced by the offset.

 [0031] The invention of claim 9 is the same as that of the invention of claim 7, and the curvature centers of the main arcs of the ball center locus in the guide grooves of the outer joint member and the inner joint member are It is characterized by being equally offset in the direction of decreasing diameter.

 [0032] With this, the groove depth of the guide groove of the inner joint member is increased, so that it is possible to more reliably prevent the ball from climbing up due to torque load. Further, the surface pressure received from the ball by the guide groove of the outer joint member can be reduced by the offset.

 The invention's effect

 [0033] As described above, according to the present invention, in the fixed type constant velocity universal joint capable of realizing a higher operating angle than the conventional one by allowing it to protrude from the guide groove of the outer joint member without dropping the ball. The force that prevents the ball and the outer joint member from interfering with each other and operates the constant velocity universal joint smoothly.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1A and Fig. IB show the fixed type (Zetsuba type) constant velocity universal joint of the present invention. Fig. 1A shows an operating angle of 0 ° and Fig. 1B shows. Indicates the limit operating angle (60 °). The components of this constant velocity universal joint are basically the same as those of the constant velocity universal joint shown in FIG. 10, and a plurality of (for example, eight) curved guide grooves lb are formed in the axial direction on the inner circumferential spherical surface la. Outer joint member 1, inner joint member 2 having a plurality of (for example, eight) curved guide grooves 2 b on the outer circumferential spherical surface 2 a in the axial direction and having a spline or selection hole 2 c, and spline A plurality of (for example, eight) ball tracks formed by the shaft 6 having one end fitted in the hole 2c, the guide groove lb of the outer joint member 1 and the guide groove 2b of the inner joint member 2 in cooperation with each other. It consists of a torque transmission ball 4 arranged one by one and a cage 5 that holds the ball 4.

[0035] The constant velocity universal joint is characterized by the ball track 3 formed by the outer ring guide groove lb and the inner ring guide groove 2b in cooperation with each other. That is, as shown in FIG. 1A, the ball track 3 has a wedge shape in which the radial intervals between the opposing guide grooves lb and 2b are narrowed toward the opening side of the outer joint member.

 [0036] The detailed shape of the ball track 3 includes the ball center locus C1 of the outer ring guide groove lb (hereinafter referred to as the outer ring ball center locus C1) and the ball center locus C2 of the inner ring guide groove 2b (hereinafter referred to as the inner ring ball center). This will be described using the locus C2. As shown in FIG. 2A, the outer ring ball center locus C1 is composed of a main arc having a radius R1 with the point O as the center. On the other hand, as shown in Fig. 2B, the inner race Bonore center trajectory C2 is composed of two trajectories with different centers of curvature, that is, a main arc C2a (range indicated by arrow A) of radius R2 centered on point O, and a main arc C2a. Fittings

2

 It is arranged on the far side and consists of a secondary arc C2b (range indicated by arrow B) of radius R3 centered on the joint center O.

 [0037] The center of curvature O of the outer ring ball center locus C1 is arranged on the back side of the outer joint member 1 relative to the center of curvature O of the main arc C2a of the inner ring ball center locus C2, and these centers of curvature O

 twenty one

, O are equally offset to the opposite side of the joint axis across the joint center o. This

2

 The ball track 3 has a wedge shape in which the radial intervals between the opposing guide grooves lb and 2b are narrowed toward the joint opening side.

[0038] Further, the radius R1 of the outer ring ball center locus C1 and the radius R2 of the main arc C2 a of the inner ring ball center locus C2 are set to be equal (R1 = R2), and these curvature centers O and O have a radius of curvature.

 1 2

It is equally offset in the increasing direction. Outer ring ball center track C1 and inner ring ball center track The main arc C2a of the trace C2 intersects with each other in a cross section passing through the joint center O and perpendicular to the joint axis, and is mirror-image-symmetric in the axial direction with the joint center O in between. A secondary arc C2 b with a radius R3 centered on the joint center O is connected to the joint back end of the main arc C2a of the inner ring ball center locus C2. The number of guide grooves is not limited to 8, but may increase to 9, 10, 11, 12,.

 [0039] FIGS. 3A and 3B show only the outer ring guide groove lb and the groove bottom of the guide portion Id in FIGS. 1A and 1B. For example, as shown in FIG. 3A, the guide portion Id is formed in an arc shape having a radius R4 with the point O on the outer diameter side of the opening of the outer joint member 1 as the center of curvature, and is formed into an outer ring guide groove lb.

 Three

 It is continuous. If the opening angle δ of the guide portion Id (the angle formed by the tangent at the opening end of the guide portion Id and the joint axis) is too small, the ball 4 and the outer joint member 1 interfere with each other. The ball that goes out of 1 can be smoothly returned to the ball track. Therefore, the size of the opening angle δ of the guide portion Id is desirably set to 5 ° to 45 °, preferably 10 ° to 20 °.

 [0040] The shape of the guide portion Id is not limited to the above. As shown in FIG. 3B, the linear shape inclined radially outward by an angle δ from the joint axial direction of the outer joint member 1, that is, the inner diameter of the guide portion Id continuously increases toward the opening side of the outer joint member 1. It may be linear. In FIG. 3B, a force that forms a corner at the boundary between the outer ring guide groove lb and the guide portion Id.

 [0041] The above-described ball track 3 has a wedge-shaped force in which the radial spacing between the opposing guide grooves lb and 2b is narrowed toward the joint opening side, as shown in FIGS. 4A and 4B, toward the joint opening side. It can also be an open wedge shape. That is, the guide groove 2b of the inner joint member 2 in the figure has a joint of the first arc part 2bl and the first arc part 2M including the joint center O and the end of the guide groove 2b on the back side of the joint. The second arc portion 2b2 is provided on the opening side and has a center of curvature at a point O offset from the joint center O in the axial direction to the back of the joint. The guide groove lb of the outer joint member 1 is formed in an arc shape with a center of curvature at a point O offset in the axial direction from the joint center O to the joint opening side. The center of curvature O of the outer ring guide groove lb and the inner ring guide groove 2b

 1

The center of curvature O of the second arc 2b2 is offset from the joint center O by the same distance on the opposite side in the axial direction, and is equidistant from the joint axis in the direction of increasing the radius of curvature. Only offset. As a result, the ball track formed by the cooperation of the outer ring guide groove lb and the corresponding inner ring guide groove 2b has a wedge shape which opens toward the opening side of the joint.

 [0042] The cage 5 is formed of an annular member as shown in FIGS. 1A and IB, and its outer peripheral surface is an outer peripheral spherical surface 5a that is in sliding contact with the inner peripheral spherical surface la of the outer joint member 1, and the inner peripheral surface is The inner peripheral spherical surface 5b is in sliding contact with the outer peripheral spherical surface 2a of the inner joint member 2. The centers of curvature of the outer peripheral spherical surface 5a and the inner peripheral spherical surface 5b of the cage 5 are both joint centers O. The same number of windows 5c as balls 4 are formed through the peripheral wall of the cage 5 by grinding or milling. The window 5c has a rectangular shape, for example, and is formed at equal intervals in the circumferential direction of the cage 5.

 As shown in FIG. 5, the inner diameter surface of the cage 5 on the joint opening side is provided with a cylindrical surface 5d having a constant inner diameter over a predetermined width, and a retaining ring 7 (ceramic ring 5d is formed in a groove portion 5dl formed in the cylindrical surface 5d. Clip) is engaged. The guide ring 8 is fitted into a narrow annular wedge space formed inside the retaining ring 7 and between the cage 5 and the window 5c. The guide ring 8 has an inner peripheral surface fitted to the spherical outer peripheral surface 2 a of the inner joint member 2 and an outer peripheral surface fitted to the inner peripheral cylindrical surface 5 d of the cage 5. Further, the outer end of the guide ring 8 comes into contact with the inner surface of the retaining ring 7. A certain gap is secured between the inner end of the guide ring 8 and the ball 4.

 [0044] The ball guide surface of the window 5c of the cage 5 has a narrow outer diameter side as shown in FIG. The window 5c of the cage 5 has an outer peripheral side window opening dimension smaller than the diameter of the ball 4. In other words, the inner diameter side of the ball guide surface facing the axial direction of the cage 5 is a force S that is a straight line parallel to each other with a space equal to the ball diameter 5c l, and the outer diameter side of the ball guide surface is The taper is tapered so that the gap is slightly narrower than the ball diameter. This tapered portion may be formed by an inclined straight line, but in order to reduce the contact pressure with the ball, it is preferable to have a concave arc shape 5c2 that matches the outer peripheral curvature of the ball.

 [0045] The constant velocity universal joint according to the present invention is configured as described above, and when the outer joint member 1 and the inner joint member 2 are at the operating angle of 0 ° in Fig. 1A, the ball 4 has the outer ring guide groove lb and the inner ring. The effect of the offset center of curvature O, O of the second arc 2b2 of the guide groove 2b is

 1 2

 It is held in a plane that includes the hand center o and is perpendicular to the axis of rotation, and torque is transmitted in this state.

[0046] The outer joint member 1 and the inner joint member 2 were bent to the limit operating angle Θ as shown in Fig. 1B. In the state, the shaft 6 contacts the open end of the outer joint member 1. The torque transmission ball 4 is oriented by the cage 5 in a plane that bisects the angle Θ, thereby ensuring constant velocity of the joint.

 [0047] Even when a large operating angle is taken, since the secondary arc C2b of the ball center locus C2 of the inner joint member 2 is an arc centered on the joint center O, the center position of the ball 4 is the joint center O. Stay away from. For this reason, it is not necessary to extend the guide groove lb of the outer joint member 1 to the opening side so that the operating angle at which the shaft 6 connected to the inner joint member 2 interferes with the outer joint member 1 can be increased. In addition, for example, at a high operating angle exceeding 50 ° and approaching 60 °, some balls 4 come out from the guide groove lb of the outer joint member 1, but the ball guide surface on the outer diameter side of the cage 5 The guide groove corresponding to the secondary arc C2b of the ball center locus C2 of the inner joint member 2 is held by the cage 5 even if it is outside the outer joint member 1. It can be held on the 2b side, and the ball 4 can be prevented from falling off the cage 5.

 [0048] Further, as described above, when the ball track 3 is formed in a wedge shape in which the radial interval between the opposing guide grooves lb and 2b is narrowed toward the joint opening side, when a load is applied to the joint, The ball 4 held by the bow track 3 is applied with a force toward the back of the joint. Specifically, as shown in FIG. 5, in a state where the ball 4 is on the ball track 3, the contact points P1, P2 between the ball track 3 and the bow 4 are plane S including the ball center (at an operating angle of 0 °, Because it is always on the joint opening side of the joint center O (the same as the section perpendicular to the axis of the joint O), a force F is applied to the ball 4 to push the cage 5 into the joint back side. At this time, as shown in FIG. 1A, the cage 5 is held in the joint back side region D of the inner circumferential spherical surface 1a of the outer joint member 1 with respect to the force F applied to the bow 4. In this constant velocity universal joint, the distance L between the opening end lc of the outer joint member 1 and the joint center O is compared by allowing the ball 4 to be protruded from the inner groove lb of the outer joint member 1 without dropping off the ball 4. The operating angle of the joint is increased. Thus, even if the distance L between the opening end lc of the outer joint member 1 and the joint center O is shortened, the inner side spherical surface D of the outer peripheral surface la of the outer joint member 1 holding the retainer 5 is reduced. As a result, the cage 5 can be held securely.

[0049] Further, in this constant velocity universal joint, the outer ring guide groove 1 is accompanied with the rotation or bending of the joint. The ball 4 that has come out from b is returned to the outer ring guide groove lb again. At this time, if the ball 4 interferes with the opening end portion of the outer joint member 1, the smooth operation of the constant velocity universal joint may be hindered. In particular, as in the present invention, when the ball track 3 has a wedge shape closed toward the joint opening side, there is a high possibility that the ball 4 and the opening end of the outer joint member 1 interfere with each other. In the constant velocity universal joint of the present invention, the ball 4 can be smoothly accommodated in the outer ring guide groove lb by the guide portion Id provided at the opening end of the outer ring guide groove lb (see FIG. 7). Therefore, interference between the ball 4 and the outer joint member 1 is avoided, and the joint can be operated smoothly.

 [0050] Also, by offsetting the curvature center O of the outer ring ball center locus C1 and the curvature center o of the inner ring ball center locus C2 both equally from the joint center in the direction in which the radius of curvature becomes longer.

2

 Since the outer ring guide groove lb becomes deeper, the force S can be more reliably prevented from climbing the ball 4 due to torque load. Also, this offset can extend the length of the outer ring guide groove lb. Furthermore, this offset reduces the surface pressure that the inner ring guide groove 2b receives from the ball 4 with a force S.

 [0051] As shown in FIG. 8, the joint can be smoothly operated even in the fixed type constant velocity universal joint having the wedge-shaped ball track 3 opened toward the joint opening side in FIGS. 4A and 4B. In other words, when the ball 4 protruding outward from the guide groove lb of the outer joint member 1 is returned to the guide groove lb as the joint rotates or bends, it is provided at the open end of the outer ring guide groove lb. The guide part Id allows the ball 4 to be smoothly accommodated in the outer ring guide groove lb. Therefore, the interference between the ball 4 and the outer joint member 1 is avoided, and the force S is used to smoothly operate the joint.

 [0052] The present invention is not limited to the above-described embodiment. For example, in the above, the center of curvature O of the ball center locus C1 and the center of curvature O1 of the main arc C2a of the ball center locus C2 O 1 radius of curvature.

 1 2

 The force is equally offset from the joint center o in the direction of increasing, but is not limited to this. For example, the centers of curvature O and O may be arranged on the joint central axis. Or you can see it in Figure 9.

 1 2

 In other words, each center of curvature ο, o is equally offset from the joint center o in the direction of decreasing the radius of curvature.

 1 2

You may do it. Thereby, since the inner ring guide groove 2b becomes deeper, it is possible to more reliably prevent the ball 4 from climbing up due to a torque load. In addition, this offset guides the outer ring. The surface pressure that the groove lb receives from the ball 4 can be reduced.

[0053] Further, in the above embodiment, the force S in which the guide groove lb of the outer joint member 1 and the inner groove 2b of the inner joint member 2 are both formed in an arc shape, and these are partially straightened. It may be formed. Alternatively, they may all be formed linearly. However, when all the guide grooves are linear, if the opposing guide grooves are parallel with the operating angle being 0 °, the cage can rotate and the position of the ball relative to the guide grooves cannot be determined. For this reason, it is necessary to form at least one pair of opposing guide grooves in a straight line that is not parallel.

 Brief Description of Drawings

 [0054] FIG. 1A is a longitudinal sectional view showing a state of a bending angle of 0 ° of a fixed type constant velocity universal joint according to the present invention.

 FIG. 1B is a longitudinal sectional view showing a state of a maximum bending angle (60 °) of the fixed type constant velocity universal joint according to the present invention.

 FIG. 2A is a longitudinal sectional view of an outer joint member.

 FIG. 2B is a longitudinal sectional view of the inner joint member.

 FIG. 3A is an enlarged view of the guide groove lb of the outer joint member 1.

 FIG. 3B is an enlarged view showing another example of the guide groove lb of the outer joint member 1.

 FIG. 4A is a longitudinal sectional view showing a state where the bending angle of a fixed type constant velocity universal joint according to another embodiment is 0 °.

 FIG. 4B is a longitudinal sectional view showing a state of a maximum bending angle (60 °) of a fixed type constant velocity universal joint according to another embodiment.

 FIG. 5 is an enlarged cross-sectional view of the ball 4 portion of the cage 5.

 FIG. 6 is an enlarged sectional view showing a window of cage 5.

 FIG. 7 is a longitudinal sectional view showing a state where a fixed type constant velocity universal joint is bent.

 FIG. 8 is a longitudinal sectional view showing a state where a fixed type constant velocity universal joint according to another embodiment is bent.

 FIG. 9 is a longitudinal sectional view showing another example of a fixed type constant velocity universal joint at a bending angle of 0 °.

 FIG. 10 is a longitudinal sectional view showing a conventional fixed type constant velocity universal joint.

Claims

The scope of the claims  [1] An outer joint member having one end opened and formed with a plurality of guide grooves extending in the axial direction on the spherical inner peripheral surface, and an inner joint formed with a plurality of guide grooves extending in the axial direction on the spherical outer peripheral surface A plurality of ball tracks formed by cooperation of the member, the guide groove of the outer joint member and the guide groove of the inner joint member, one torque transmission ball disposed on each ball track, and a torque transmission ball. For fixed type constant velocity universal joints equipped with a retainer! /  A fixed type constant velocity universal joint characterized in that the joint opening side end of the guide groove of the outer joint member is a guide portion opened radially outward. [2] The fixed type constant velocity universal joint according to claim 1, wherein the ball track has a wedge shape in which a radial interval between opposing guide grooves is narrowed toward an opening side of the outer joint member. Fixed type constant velocity universal joint. [3] In the fixed type constant velocity universal joint according to claim 1, the region including the end portion on the inner side of the joint in the guide groove of the inner joint member is an arc centered on the joint center and accommodates the ball. A fixed type constant velocity universal joint characterized in that it can be protruded from the guide groove of the outer joint member without dropping the ball by making the outer side opening size of the cage window smaller than the diameter of the ball. . [4] In the fixed type constant velocity universal joint according to claim 2, the guide part is a curved shape having a center of curvature on the outer diameter side of the opening of the outer joint member, etc. Fast universal joint. [5] The fixed type constant velocity universal joint according to claim 2 is characterized in that the guide portion has a linear shape whose inner diameter continuously increases toward the opening of the outer joint member. Fixed type constant velocity universal joint.  [6] In the fixed type constant velocity universal joint according to claim 1, the ball center locus in the guide groove of the outer joint member and the ball center locus force S in the guide groove of the inner joint member, the main arcs having equal radii, respectively. Prepared, The center of curvature of the main arc of the ball center trajectory in the guide groove of the outer joint member is arranged on the deeper side of the joint than the center of curvature of the main arc of the ball center trajectory in the guide groove of the inner joint member, and these centers of curvature Is a fixed type constant velocity universal joint that is equally offset on the opposite side of the joint axial direction across the joint center. [7] In the fixed type constant velocity universal joint according to claim 6, the ball center locus in the guide groove of the inner joint member is extended from the joint back side end portion of the main arc, and the secondary arc having the joint center as the center of curvature. And the outside opening of the cage window that accommodates the ball is smaller than the diameter of the ball, so that the ball can be protruded from the guide groove of the outer joint member without dropping. Fixed type constant velocity universal joint characterized by  [8] In the fixed type constant velocity universal joint according to claim 7, the curvature center force S of the main arc of the ball center locus in the inner groove of the outer joint member and the inner joint member, and the radius of curvature from the joint center. Is a fixed type constant velocity universal joint that is equally offset in the direction in which the length increases. [9] In the fixed type constant velocity universal joint according to claim 7, the curvature center force S of the main arc of the ball center locus in the inner groove of the outer joint member and the inner joint member, and the radius of curvature from the joint center. Is a fixed type constant velocity universal joint that is equally offset in the direction of shortening.