JP2019011793A - Stationary type constant velocity universal joint - Google Patents

Abstract

To provide a fixed type constant velocity universal joint that is simple and can solve the problems of low heat generation and strength at a high operating angle. A fixed type constant velocity universal joint 1 including track grooves 7 and 9, an outer joint member 2, an inner joint member 3, a torque transmission ball 4 and a cage 5, The track groove is composed of a first track groove portion and a second track groove portion, and the first track groove portion track center line curvature center is offset in the axial direction toward the back side with respect to the joint center O. The track center line of the second track groove portion is formed so as to be inclined toward the opening side in a direction in which the distance from the joint axis NN approaches, and smoothly extends to the track center line of the first track groove portion. The track center line Y of the track groove of the inner joint member is a pair of the outer joint member on the basis of a plane P including the joint center and perpendicular to the joint axis NN at an operating angle of 0 °. Pair of track center line X and mirror image of track groove 7 Characterized in that it is formed in. [Selection] Figure 1

Description

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

  The constant velocity universal joint that constitutes the power transmission system of automobiles and various industrial machines connects the two shafts on the drive side and the driven side so that torque can be transmitted, and transmits rotational torque at a constant speed even if the two shafts have an operating angle. can do. Constant velocity universal joints are broadly classified into fixed constant velocity universal joints that allow only angular displacement and sliding constant velocity universal joints that allow both angular displacement and axial displacement. In the drive shaft that transmits power to the drive wheel, a sliding type constant velocity universal joint is used on the differential side (inboard side), and a fixed type constant velocity universal joint is used on the drive wheel side (outboard side). The

  In recent years, fixed-type constant velocity universal joints have a track groove intersection type or counter track groove aimed at reducing heat generation by reducing the contact force between the spherical inner surface and spherical outer surface of the cage to achieve higher performance. Various types of constant velocity universal joints have been proposed (Patent Documents 1 to 4). These constant velocity universal joints are becoming effective means for meeting the environmental performance required for automobiles and for severe use environments of industrial machines.

  The constant velocity universal joints having the structures of Patent Document 1 and Patent Document 2 have extremely high functions, but require high machining accuracy and dimensional accuracy. Conventional Zepper type constant velocity universal joints and undercut free There is a high possibility that the cost will increase compared to the type constant velocity universal joint. As a means for solving these problems, there has been proposed a structure in which a track groove as in Patent Document 3 is constituted by three arcs in the longitudinal direction, and high efficiency is realized by balancing forces acting on the cage at a predetermined angle. Yes.

  In addition, the fixed type constant velocity universal joint has a shear failure mode of the cage pillar due to the spherical edge of the outer joint member and the inner joint member, which is one of the damage modes at high angles, and the strength of the cage. In order to ensure this, as described in Patent Document 4, it is necessary to design so as to adjust the positional relationship between the spherical edge portion of the outer joint member and the spherical edge portion of the inner joint member.

Japanese Patent No. 5138449 Special table 2007-503556 gazette Japanese Patent No. 5634777 Japanese Patent No. 4133415

  The fixed type constant velocity universal joint described in Patent Document 3 switches the wedge angle of the central track groove portion formed by an arc with a small radius between the track groove portion on the opening side and the track groove portion on the back side, and changes the force acting on the cage. By balancing, high efficiency is realized in the normal angle range (low operating angle). The fixed type constant velocity universal joint of Patent Document 3 is not intended to increase the efficiency of the high operating angle region and to reduce the heat generation associated therewith, and in addition to the fact that the track groove is composed of three arcs. The effect of reversing the wedge angle of the track groove portion is determined by the connection position between the central track groove portion, the opening side track groove portion, and the back side track groove portion, and therefore needs to be finished with high accuracy.

  Further, in the structure of Patent Document 3, the outer joint member as described in Patent Document 4 is in a state of a rust angle at the time of a high operating angle, like the Rzeppa type constant velocity universal joint and the undercut free type constant velocity universal joint. Therefore, it is necessary to take a design in consideration of the shear failure mode of the cage column due to the spherical edge portion of the inner joint member biting in.

  In view of the above problems, an object of the present invention is to provide a fixed type constant velocity universal joint that has a simple structure and can solve the problems of low heat generation and strength at a high operating angle.

  As technical means for achieving the above-mentioned object, the present invention provides an outer joint member having a plurality of track grooves extending in the longitudinal direction on a spherical inner peripheral surface and having an opening side and a back side that are separated in the axial direction. An inner joint member in which a plurality of track grooves extending in the longitudinal direction on the spherical outer peripheral surface are formed to face the track grooves of the outer joint member, a torque transmitting ball incorporated between the opposed track grooves, and the torque A fixed type that includes a spherical outer peripheral surface that holds a transmission ball and is guided by the spherical outer peripheral surface of the outer joint member and a spherical inner peripheral surface that is guided by the spherical outer peripheral surface of the inner joint member. In the quick universal joint, the track groove 7 of the outer joint member includes an arc-shaped first track groove portion 7a disposed on the back side, and a linear second track groove portion 7b disposed on the opening side. Consists of The center of curvature of the track center line Xa of the first track groove portion 7a is offset in the axial direction toward the back side with respect to the joint center O, and the track center line Xb of the second track groove portion 7b is Inclined in the direction in which the distance from the joint axis NN approaches the opening side, and is smoothly connected to the track center line Xa of the first track groove portion 7a, and the track groove of the inner joint member 9 is a track center line of the track groove 7 that forms a pair of the outer joint member with reference to a plane P that includes the joint center O and is perpendicular to the joint axis NN in a state where the operating angle is 0 °. It is characterized by being formed mirror-symmetric with X.

  With the above configuration, the problem of low heat generation and strength at a high operating angle can be solved while having a simple structure.

  Specifically, the inclination angle β of the track center line Xb of the second track groove portion 7b with respect to the joint axis NN is preferably larger than the offset angle η. As a result, the force acting on the cage at a high operating angle is reduced without impairing the operability, low heat generation is obtained, and the spherical edge portion of the outer joint member and the inner joint member bites into the cage. Strength reduction can be prevented.

  The inclination angle β of the track center line Xb of the second track groove portion 7b with respect to the joint axis NN is preferably less than 15 °. Thereby, the depth of the track groove at the opening end of the outer joint member can be ensured, and the strength and durability at a high operating angle can be ensured.

  The center of curvature of the track center line Xa of the first track groove portion 7a is preferably offset in the radial direction with respect to the joint axis NN. Thereby, the groove depth of the track groove at a high operating angle can be adjusted.

  The center of curvature of the spherical outer circumferential surface of the cage and the center of curvature of the spherical inner circumferential surface are offset by an equal amount on the opposite side in the axial direction with respect to the joint center (O), thereby opening the cage on the opening side. Since the thickness of the plate increases, the strength at a high operating angle is improved.

  Since the number of the above-described torque transmission balls is eight, the joint is light and compact in combination with a simple track groove structure.

  ADVANTAGE OF THE INVENTION According to this invention, although it is a simple structure, the fixed type constant velocity universal joint which can solve the problem of the low heat_generation | fever property at the time of a high working angle and intensity | strength is realizable.

(A) is a longitudinal sectional view of the fixed type constant velocity universal joint according to the first embodiment of the present invention, and (b) is a right side view of (a). (A) A figure is a longitudinal cross-sectional view of Fig.1 (a) outer joint member, (b) A figure is a right view of (a) figure. (A) A figure is a longitudinal cross-sectional view of Fig.1 (a) inner side coupling member, (b) A figure is a right view of (a) figure. FIG. 1A is a longitudinal sectional view of the cage of FIG. 1A, and FIG. 1B is a transverse sectional view taken along line AA in FIG. (A) is a longitudinal sectional view showing a wedge angle in a state where the operating angle is 0 °, and (b) is a longitudinal sectional view showing a wedge angle in a state where the operating angle is low. (A) A figure is a longitudinal cross-sectional view which shows the wedge angle in the state of a medium working angle, (b) A figure is a longitudinal cross-sectional view which shows the wedge angle in the state of a high operating angle. It is a figure which shows the analysis result of the spherical force which acts between a holder | retainer and an inner joint member. It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which concerns on the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which concerns on the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which concerns on the 4th Embodiment of this invention.

  A fixed type constant velocity universal joint according to a first embodiment of the present invention will be described with reference to FIGS. Fig.1 (a) is a longitudinal cross-sectional view of the fixed type constant velocity universal joint which concerns on the 1st Embodiment of this invention, FIG.1 (b) is a right view of Fig.1 (a). The fixed type constant velocity universal joint 1 of the present embodiment mainly includes an outer joint member 2, an inner joint member 3, a torque transmission ball (also simply referred to as a ball) 4, and a cage 5. Eight track grooves 7 are formed on the spherical inner peripheral surface 6 of the outer joint member 2 at equal intervals in the circumferential direction and along the axial direction. Eight track grooves 9 facing the track grooves 7 of the outer joint member 2 are formed on the spherical outer peripheral surface 8 of the inner joint member 3 at equal intervals in the circumferential direction and along the axial direction. Eight balls 4 for transmitting torque are incorporated one by one between the track groove 7 of the outer joint member 2 and the track groove 9 of the inner joint member 3. A cage 5 for holding the ball 4 is disposed between the spherical inner peripheral surface 6 of the outer joint member 2 and the spherical outer peripheral surface 8 of the inner joint member 3. The inner joint member 3 is provided with a spline hole 10 on the inner periphery, and is connected to a shaft (not shown). The outer peripheral surface of the outer joint member 2 and the outer peripheral surface of the shaft are covered with boots (not shown), and grease as a lubricant is sealed inside the joint.

  The ball 4 is accommodated in the pocket 5 a of the cage 5. The spherical outer peripheral surface 12 of the cage 5 is slidably fitted to the spherical inner peripheral surface 6 of the outer joint member 2, and the spherical inner peripheral surface 13 of the cage 5 slides on the spherical outer peripheral surface 8 of the inner joint member 3. Fit and guide freely.

  The spherical inner peripheral surface 6 of the outer joint member 2 and the spherical outer peripheral surface 8 of the inner joint member 3 both have a center of curvature at the joint center O. The track center line X of the track groove 7 of the outer joint member 2 and the track center line Y of the track groove 9 of the inner joint member 3 are indicated by a one-dot chain line.

  The track groove 7 of the outer joint member 2 will be described with reference to FIGS. 2 (a) and 2 (b). Fig.2 (a) is a longitudinal cross-sectional view of the outer joint member of Fig.1 (a), and FIG.2 (b) is a right view of FIG.2 (a). As shown in FIG. 2 (a), the track groove 7 of the outer joint member 2 includes a first track groove portion 7a located on the back side of the outer joint member 2 and a second track groove portion 7b located on the opening side. Composed. The track center line Xa of the first track groove portion 7a has an arc shape with a radius of curvature R, and the center of curvature O1 is offset in the axial direction from the joint center O toward the back side (offset amount f).

  Let D be the intersection of the plane P including the joint center O and perpendicular to the joint axis N-N and the track center line Xa of the first track groove portion 7a at an operating angle of 0 °. The angle formed by the straight line connecting the intersection D and the center of curvature O1 and the straight line connecting the intersection D and the joint center O is the offset angle η.

  The track center line Xb of the second track groove portion 7b is linear, and is inclined at an inclination angle β toward the joint axis NN toward the opening side of the outer joint member 2. The track center line Xa of the first track groove portion 7a and the track center line Xb of the second track groove portion 7b are smoothly connected at the connection point B.

  The track groove 9 of the inner joint member 3 will be described with reference to FIGS. 3 (a) and 3 (b). 3A is a longitudinal sectional view of the inner joint member of FIG. 1A, and FIG. 3B is a right side view of FIG. As shown in FIG. 3 (a), the track groove 9 of the inner joint member 3 includes a first track groove portion 9a located on the opening side of the outer joint member 2 and a second track groove portion 9b located on the back side. Composed. The track center line Ya of the first track groove portion 9a has an arc shape with a radius of curvature R, and the center of curvature O2 is offset in the axial direction from the joint center O toward the opening (offset amount f).

  Similar to the first track groove portion 7a of the outer joint member 2 described above, the plane P including the joint center O and perpendicular to the joint axis NN in the state of the operating angle of 0 ° and the track center of the first track groove portion 7a. Let E be the intersection of the lines Xa. The angle formed by the straight line connecting the intersection point E and the center of curvature O2 and the straight line connecting the intersection point E and the joint center O is the offset angle η.

  The track center line Yb of the second track groove portion 9b is linear and is inclined toward the inner side of the outer joint member 2 at an inclination angle β so as to approach the joint axis NN. The track center line Ya of the first track groove 9a and the track center line Yb of the second track groove 9b are smoothly connected at the connection point C.

The offset amount f, the offset angle η of the first track groove portions 7a and 9a of the outer joint member 2 and the inner joint member 3, and the inclination angle β of the second track groove portions 7b and 9b will be described. In the fixed type constant velocity universal joint 1 of the present embodiment, the relationship between the offset amount f, the offset angle η, and the inclination angle β is as follows in order to obtain the effects of low heat generation, strength, and durability at a high operating angle. Is set.
η <β <15 °, η ≧ 5 °
Here, there is a relationship of η = sin ⁻¹ (f / R).

  The reason why the above relationship is set will be described next. When the offset angle η is less than 5 °, the operability of the joint is significantly reduced. By making the inclination angle β larger than the offset angle η, the wedge angle δ acting on the ball 4 by the offset angle η is maintained, and the operability is not impaired. Further, the force acting on the cage 5 at a high operating angle is reduced, low heat generation is obtained, and the strength of the cage 5 is prevented from lowering due to the spherical edges of the outer joint member 2 and the inner joint member 3 biting in. be able to. When the inclination angle β is 15 ° or more, the track groove depth at the opening end portion of the second track groove portion 7b of the outer joint member 2 becomes too shallow, so that the strength and durability at a high operating angle are lowered.

  4 (a) and 4 (b) show the cage. 4A is a longitudinal sectional view of the cage of FIG. 1A, and FIG. 4B is a transverse sectional view taken along the line AA in FIG. 4A. The cage 5 has a spherical outer peripheral surface 12 and a spherical inner peripheral surface 13, and the centers of curvature of the spherical outer peripheral surface 12 and the spherical inner peripheral surface 13 are formed at the joint center O. The cage 5 is provided with eight pockets 5a at equal intervals in the circumferential direction, and accommodates and holds eight balls 4 (not shown) one by one. A column portion 5b is formed between pockets 5a adjacent in the circumferential direction.

  Next, the operation of the fixed type constant velocity universal joint 1 of the present embodiment will be described with reference to FIGS. 5 (a) to 6 (b). In summary, the fixed type constant velocity universal joint 1 of the present embodiment opens the ball 4 at the position of the apex phase angle 0 ° shown in FIG. The opening direction of the wedge angle when moving to the side is reversed from the back side to the opening side. When the operating angle is further increased, the opening direction of the wedge angle of the ball 4 is reversed to the opening side in the circumferential range centering on the phase angle of 0 °, so that the force by which the ball 4 pushes the cage 5 is moved to the opening side. As the number of heads increases, the force acting on the cage 4 is balanced between the back side and the opening side, and the spherical force is reduced.

  This will be specifically described with reference to FIGS. 5 (a) to 6 (b). FIG. 5A shows a state where the operating angle is 0 °. In this state, the wedge angles δ of all the track grooves 7 and 9 including the phase angles of 0 ° and 180 ° are open toward the back side of the outer joint member 2. Therefore, the force with which the ball 4 pushes the cage 5 is all directed toward the back side. A large spherical force is generated.

  FIG. 5B shows a state with a low operating angle θ1 (for example, about 8 °). Even in the state of the low operating angle θ1, the wedge angles δ of all the track grooves 7 and 9 including the phase angles 0 ° and 180 ° are open toward the back side of the outer joint member 2. Therefore, the force with which the ball 4 pushes the cage 5 is all directed toward the back side. Here, since the track grooves 7 and 9 and the ball 4 are in contact with each other with a contact angle, the contact point is located on the side surfaces of the track grooves 7 and 9 that are slightly apart from the groove bottoms of the track grooves 7 and 9. 5A to 6B, the wedge angle δ is illustrated using the groove bottoms of the track grooves 7 and 9 for the sake of simplicity. The actual wedge angle at the contact point and the illustrated wedge angle δ are slightly different in magnitude, but the reversal behavior of the opening direction of the wedge angle is the same.

  FIG. 6A shows a state at a medium operating angle θ2 (for example, about 20 °). In the state of the medium operating angle θ2 in which the operating angle is increased, the wedge angles δ of all the track grooves 7 and 9 including the phase angles 0 ° and 180 ° are open toward the back side of the outer joint member 2, The wedge angle δ of the track grooves 7 and 9 having a phase angle of 0 ° is close to 0 °. When the operating angle is slightly increased from this state, the opening direction of the wedge angle δ of the track grooves 7 and 9 having a phase angle of 0 ° is reversed and directed toward the opening side.

  FIG. 6B shows a state of a high operating angle θ3 (for example, about 40 °). When the operating angle is increased from the middle operating angle θ2, first, the opening direction of the wedge angle δ with the phase angle of 0 ° is reversed and directed toward the opening side. Further, when the operating angle is further increased, the opening direction of the wedge angle δ of the track grooves 7 and 9 near the phase angle of 0 ° is reversed and is directed toward the opening side, and the state of the high operating angle shown in FIG. Become. In this state, the opening direction of the wedge angle of the ball 4 is reversed to the opening side in the circumferential range centering on the phase angle of 0 °, so that the number of the force by which the ball 4 pushes the cage 5 is directed to the opening side. As a result, the force acting on the cage 4 is balanced between the back side and the opening side, and the spherical force is reduced.

  FIG. 7 shows the analysis result of the spherical force between the cage 5 and the inner joint member 3 of the fixed type constant velocity universal joint 1 of the present embodiment. The fixed constant velocity universal joint 1 of the present embodiment has an offset angle η of 5 ° and an inclination angle β of 8 °. The conventional product is an 8-ball Zeppa constant velocity universal joint. As can be seen from FIG. 7, the spherical force acting between the cage 5 and the inner joint member 3 of the fixed type constant velocity universal joint 1 of the present embodiment has a high operating angle range value in the low operating angle range. It is smaller than the value, and is remarkably reduced as compared with the value of the high operating angle range of the conventional product. Thereby, the heat_generation | fever at the time of a high operating angle is suppressed.

  As described above, the fixed type constant velocity universal joint 1 of the present embodiment has a simple structure including the arc-shaped first track groove portions 7a and 9a and the linear second track groove portions 7b and 9b. The problem of low heat generation and strength at high operating angles can be solved. Specifically, it can be manufactured with the same processing accuracy and cost as conventional Rzeppa type constant velocity universal joints and undercut-free type constant velocity universal joints. improves. Further, since the forces acting on the cage 5 at a high operating angle are balanced, the shear fracture mode of the cage column portion 5b due to the biting of the spherical edge portions of the outer joint member 2 and the inner joint member 3 does not occur, and the strength is increased. improves.

  Next, a fixed type constant velocity universal joint according to a second embodiment of the present invention will be described with reference to FIG. In the fixed type constant velocity universal joint 1 of the present embodiment, the positions of the curvature centers O3 and O4 of the track centerlines Xa and Ya of the first track groove portions 7a and 9a of the outer joint member 2 and the inner joint member 3 are the first. Different from the embodiment. Other configurations are the same as those of the first embodiment. Parts having similar functions are denoted by the same reference numerals, and only the main points will be described. The same applies to the embodiments described later.

  The track center line Xa of the first track groove portion 7a of the outer joint member 2 is offset in the axial direction toward the back side of the outer joint member 2 with respect to the joint center O (offset amount f1), and the axis of the joint It is formed in an arc shape with a curvature radius R1 having a curvature center O3 that is offset in the radial direction (offset amount f2) with respect to NN.

  The track center line Ya of the first track groove portion 9a of the inner joint member 3 is offset in the axial direction toward the opening side of the outer joint member 2 with respect to the joint center O (offset amount f1), and the axis of the joint It is formed in an arc shape having a radius of curvature R1 having a center of curvature O4 that is offset in the radial direction (offset amount f2) with respect to NN.

  The relationship among the offset amount f, the offset angle η, and the inclination angle β in the fixed type constant velocity universal joint 1 of the present embodiment is the same as that of the first embodiment. Thereby, it becomes the same as the action | operation of the fixed type constant velocity universal joint of 1st Embodiment, and an effect. Therefore, the above-described content of the fixed type constant velocity universal joint according to the first embodiment is applied mutatis mutandis, and description thereof is omitted. The same applies to the embodiments described later.

  Next, a fixed type constant velocity universal joint according to a third embodiment of the present invention will be described with reference to FIG. In the fixed type constant velocity universal joint 1 of the present embodiment, the track center lines Xa of the first track groove portions 7a and 9a of the outer joint member 2 and the inner joint member 3 and the curvature centers O5 and O6 of Ya are the axis N of the joint. The difference from −N in the second embodiment is that it is offset to the opposite side in the radial direction. Other configurations are the same as those of the second embodiment.

  The track center line Xa of the first track groove portion 7a of the outer joint member 2 is offset in the axial direction (offset amount f3) toward the inner side of the outer joint member 2 with respect to the joint center O, and in the radial direction. It is formed in an arc shape having a radius of curvature R2 having a center of curvature O5 offset (offset amount f4).

  The track center line Ya of the first track groove portion 9a of the inner joint member 3 is offset in the axial direction toward the opening side of the outer joint member 2 with respect to the joint center O (offset amount f3), and in the radial direction. It is formed in an arc shape having a radius of curvature R2 having a center of curvature O6 offset (offset amount f4).

  A fixed type constant velocity universal joint according to a fourth embodiment of the present invention will be described with reference to FIG. In the fixed type constant velocity universal joint 1 of the present embodiment, the center of curvature of the spherical outer peripheral surface 12 of the cage 5 and the center of curvature of the spherical inner peripheral surface 13 are offset by an amount equal to the axially opposite side with respect to the joint center O. This is different from the first embodiment.

  The center of curvature O10 of the spherical outer peripheral surface 12 of the cage 5 is offset by a slight amount (offset amount f6) in the axial direction toward the opening side of the outer joint member 2 with respect to the joint center O. The center of curvature O9 of the spherical inner peripheral surface 13 is offset with respect to the joint center O by a slight amount (offset amount f6) in the axial direction on the back side of the outer joint member 2. Thereby, since the thickness of the inner side of the cage 5 is increased, the strength at a high operating angle is improved.

  The track center line Xa of the first track groove portion 7a of the outer joint member 2 has an arc shape with a curvature radius R3, and the curvature center O7 is offset in the axial direction from the joint center O toward the back side (offset amount f5). ing. The track center line Ya of the first track groove portion 9a of the inner joint member 3 has an arc shape with a radius of curvature R3, and the center of curvature O8 is offset in the axial direction from the joint center O toward the opening (offset amount f5). ing.

  The fixed type constant velocity universal joint 1 according to each embodiment described above has a simple structure including the arc-shaped first track groove portions 7a and 9a and the linear second track groove portions 7b and 9b, and has a high operation. It is possible to solve the problem of low heat generation and strength during cornering. Specifically, it can be manufactured with the same processing accuracy and cost as conventional Rzeppa type constant velocity universal joints and undercut-free type constant velocity universal joints. improves. Further, since the forces acting on the cage 5 at a high operating angle are balanced, the shear fracture mode of the cage column portion 5b due to the biting of the spherical edge portions of the outer joint member 2 and the inner joint member 3 does not occur, and the strength is increased. improves.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the scope of the present invention. The scope of the present invention is not limited to patents. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Fixed type constant velocity universal joint 2 Outer joint member 3 Inner joint member 4 Torque transmission ball 5 Cage 5a Pocket 6 Spherical inner peripheral surface 7 Track groove 7a First track groove portion 7b Second track groove portion 8 Spherical outer peripheral surface 9 Track Groove 9a First track groove portion 9b Second track groove portion 12 Spherical outer peripheral surface 13 Spherical inner peripheral surface N Joint axis O Joint center O1 Center of curvature O2 Center of curvature O3 Center of curvature O4 Center of curvature O5 Center of curvature O6 Center of curvature O7 Center of curvature O8 Curvature center P Plane R Curvature radius R1 Curvature radius R2 Curvature radius R3 Curvature radius X Track center line Xa Track center line Xb Track center line Y Track center line Ya Track center line Yb Track center line f Offset amount f1 Offset amount f2 Offset amount f3 Offset amount f4 Offset amount f5 Offset amount f6 Offset amount β Inclination angle δ Wedge angle η Offset Door angle θ operating angle

Claims (6)

A plurality of track grooves extending in the longitudinal direction are formed on the spherical inner peripheral surface, and an outer joint member having an opening side and a back side separated in the axial direction, and a plurality of track grooves extending in the longitudinal direction on the spherical outer peripheral surface are the outer joints. An inner joint member formed to face the track grooves of the member, a torque transmission ball incorporated between the opposed track grooves, and the torque transmission ball is held and guided to the spherical outer peripheral surface of the outer joint member. A fixed constant velocity universal joint comprising a spherical outer peripheral surface and a cage formed with a spherical inner peripheral surface guided by the spherical outer peripheral surface of the inner joint member,
The track groove (7) of the outer joint member includes an arc-shaped first track groove portion (7a) disposed on the back side and a linear second track groove portion (7b) disposed on the opening side. And consists of
The center of curvature of the track center line (Xa) of the first track groove (7a) is offset in the axial direction toward the back side with respect to the joint center (O),
The track center line (Xb) of the second track groove portion (7b) is formed so as to be inclined toward the opening side in the direction in which the distance from the joint axis (N-N) approaches. Smoothly connected to the track center line (Xa) of the groove (7a),
The track center line (Y) of the track groove (9) of the inner joint member is based on a plane (P) that includes the joint center (O) and is orthogonal to the joint axis (N-N) at an operating angle of 0 °. As described above, the fixed type constant velocity universal joint is formed so as to be mirror-symmetrical with the track center line (X) of the track groove (7) which forms a pair of the outer joint member.   The inclination angle (β) of the track center line (Xb) of the second track groove portion (7b) with respect to the joint axis (N-N) is larger than the offset angle (η). Fixed constant velocity universal joint.   The inclination angle (β) of the orbit center line (Xb) of the second track groove portion (7b) with respect to the joint axis (N-N) is less than 15 °. Fixed constant velocity universal joint described in 1.   The center of curvature of the track center line (Xa) of the first track groove (7a) is offset in the radial direction with respect to the joint axis (N-N). The fixed type constant velocity universal joint as described in any one of Claims.   The center of curvature of the spherical outer peripheral surface of the cage and the center of curvature of the spherical inner peripheral surface are offset by an equal amount on the opposite side in the axial direction with respect to the joint center (O). The fixed constant velocity universal joint according to any one of claims 4 to 4.   6. The fixed type constant velocity universal joint according to claim 1, wherein the number of the torque transmission balls is eight.