WO2019003765A1 - Fixed-type constant-velocity universal joint - Google Patents

Abstract

A fixed-type constant-velocity universal joint, comprising: an outer-side joint member in which a plurality of track grooves extending in a longitudinal direction is formed in a spherical inner peripheral surface, and which has an open side and a recessed side separated in an axial direction; an inner-side joint member in which a plurality of track grooves extending in the longitudinal direction is formed in a spherical outer peripheral surface so as to oppose the track grooves of the outer-side joint member; torque-transmitting balls fitted in between the opposing track grooves; and a holder which holds the torque-transmitting balls, and in which are formed a spherical outer peripheral surface guided to the spherical outer peripheral surface of the outer-side joint member and a spherical inner peripheral surface guided to the spherical outer peripheral surface of the inner-side joint member; wherein the fixed-type constant-velocity universal joint is characterized in that: the track grooves 7 of the outer-side joint member 2 are configured from an arcuate first track groove part 7a disposed in the recessed side, and a linear second track groove part 7b disposed in the open side; the center of curvature of a track center line Xa of the first track groove part 7a is axially offset from a joint center O toward the recessed side; a track center line Xb of the second track groove part 7b is formed at an incline in a direction such that the distance to an axis line N-N of the joint decreases toward the open side, the track center line Xb being smoothly connected to the track center line Xa of the first track groove part 7a; and track center lines Y of the track grooves 9 of the inner-side joint member are formed in mirror symmetry with the track center lines X of the pair of track grooves 7 of the outer-side joint member, the reference being a plane P that includes the joint center O at a working angle of 0º and that is orthogonal to the axis line N-N of the joint.

Description

Fixed type constant velocity universal joint

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

A constant velocity universal joint that constitutes a power transmission system of an automobile or various industrial machines connects two shafts on the drive side and the driven side in a torque transmittable manner, and transmits rotational torque at a constant speed even when the two axes operate at an operating angle. can do. Constant velocity universal joints are roughly classified into fixed type constant velocity universal joints that allow only angular displacement, and sliding constant velocity universal joints that allow both angular displacement and axial displacement, for example, from an automobile engine For drive shafts that transmit power to the drive wheels, sliding constant velocity universal joints are used on the differential side (inboard side), and fixed constant velocity universal joints are used on the driving wheel side (outboard side) Ru.

In recent years, the fixed type constant velocity universal joint reduces the contact force between the spherical inner peripheral surface and the spherical outer peripheral surface of the cage in order to further improve the performance, and the track groove crossing type and counter track groove aiming at low heat generation. Various types of constant velocity universal joints such as types have been proposed (Patent Documents 1 to 4). These constant velocity universal joints are becoming an effective means for responding to environmental performance required for automobiles and for severe usage environments of industrial machines.

The constant velocity universal joints of the structures of Patent Document 1 and Patent Document 2 have very high functions, but require high processing accuracy and dimensional accuracy, and the conventional Zeppa type constant velocity universal joints and undercut free There is a high possibility of cost increase compared with the mold constant velocity universal joint. As means for solving these problems, a track groove as in Patent Document 3 is formed by three arcs in the longitudinal direction, and a mechanism that achieves high efficiency by balancing the forces acting on the cage at a predetermined angle is also proposed. There is.

In the fixed type constant velocity universal joint, there is a shear failure mode of the cage column due to the biting in of 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 cage strength is In order to ensure the above, it is necessary to design 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 as described in Patent Document 4.

Patent No. 5138449 gazette Japanese Patent Application Publication No. 2007-503556 Patent No. 5634777 gazette Patent No. 4133415 gazette

The fixed type constant velocity universal joint described in Patent Document 3 switches the wedge angle of the central track groove portion formed of a small radius arc by the track groove portion on the opening side and the track groove portion on the back side, and exerts a 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 accordingly, and in addition to the track groove being configured by three arcs. The effect of reversing the wedge angle of the track groove portion is determined by the connection position of the central track groove portion, the opening side track groove portion, and the back side track groove portion, and therefore, it is necessary to finish with high accuracy.

Further, in the structure of Patent Document 3, the outer joint member as described in Patent Document 4 is in the state of the same wedge angle as that of the Zeppa type constant velocity universal joint and the undercut free type constant velocity universal joint at the high operating angle. And it becomes necessary to take design in consideration of the shear failure mode of the cage column by the biting in of the spherical edge of the inner joint member.

In view of the above problems, the present invention has an object to provide a fixed type constant velocity universal joint capable of solving the problems of low heat buildup and strength at a high operating angle while having a simple structure.

As technical means for achieving the above-mentioned object, the present invention provides an outer joint member in which a plurality of track grooves extending in the longitudinal direction are formed on the spherical inner peripheral surface, and has an axially spaced opening side and back side. An inner joint member in which a plurality of track grooves extending in the longitudinal direction are formed on the spherical outer peripheral surface so as to face the track grooves of the outer joint member; a torque transmitting ball incorporated between the opposing track grooves; Fixed type comprising a spherical outer peripheral surface which holds a transmission ball and is guided to the spherical outer peripheral surface of the outer joint member and a cage having a spherical inner peripheral surface which is guided to the spherical outer peripheral surface of the inner joint member In the fast 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. Composed of The center of curvature of the track center line Xa of the first track groove 7a is axially offset toward the back with respect to the joint center O, and the track center line Xb of the second track groove 7b is , Formed so as to be inclined toward the opening side in a direction in which the distance with the axis N-N of the joint approaches and smoothly connected to the track center line Xa of the first track groove portion 7a; The track center line Y of the groove 9 has the joint center O at the operating angle of 0 ° and the track center of the track groove 7 which is the pair of outer joint members with reference to the plane P orthogonal to the joint axis NN. It is characterized in that it is formed in mirror symmetry with the line X.

According to the above configuration, it is possible to solve the problems of low heat buildup and strength at a high operating angle while having a simple structure.

Specifically, it is preferable that the inclination angle β of the track center line Xb of the second track groove portion 7b with respect to the axis N-N of the joint is 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, and low heat buildup is obtained, and the spherical edge portions of the outer joint member and the inner joint member bite into the cage It is possible to prevent strength reduction.

The inclination angle β of the track center line Xb of the second track groove 7b with respect to the axis N-N of the above joint is preferably less than 15 °. Thereby, the depth of the track groove at the open end of the outer joint member can be secured, and the strength and durability at the high operation angle can be secured.

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

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 axially opposite to each other with respect to the joint center (O). Since the wall thickness is increased, the strength at high operating angles is improved.

The eight torque transmitting balls described above, combined with the simple track groove structure, make the joint lightweight and compact.

According to the present invention, it is possible to realize a fixed type constant velocity universal joint capable of solving the problems of low heat buildup and strength at a high operating angle while having a simple structure.

FIG. 1 is a longitudinal sectional view of a fixed type constant velocity universal joint according to a first embodiment of the present invention. It is a right view of FIG. 1 a. FIG. 2 is a longitudinal cross-sectional view of the outer joint member of FIG. 1a. It is a right view of Drawing 2a. FIG. 1 b is a longitudinal cross-sectional view of the inner joint member of FIG. It is a right view of FIG. 3 a. Figure 2 is a longitudinal cross-sectional view of the cage of Figure 1a; Fig. 4b is a cross-sectional view taken along the line AA of Fig. 4a. It is a longitudinal cross-sectional view which shows the wedge angle of the state of operating angle 0 degree. It is a longitudinal cross-sectional view which shows the wedge angle in the state of a low operating angle. It is a longitudinal cross-sectional view which shows the wedge angle of the state of a middle working angle. It 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 based on FIGS. 1 to 6. FIG. 1a is a longitudinal sectional view of a fixed type constant velocity universal joint according to a first embodiment of the present invention, and FIG. 1b is a right side view of FIG. 1a. The fixed type constant velocity universal joint 1 according to this embodiment mainly includes an outer joint member 2, an inner joint member 3, a torque transmitting ball (also simply referred to as a ball) 4 and a cage 5. Eight track grooves 7 are formed on the spherical inner circumferential surface 6 of the outer joint member 2 at equal intervals in the circumferential direction and along the axial direction. On the spherical outer peripheral surface 8 of the inner joint member 3, eight track grooves 9 opposed to the track grooves 7 of the outer joint member 2 are formed along the circumferential direction at equal intervals in the circumferential 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. 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, a cage 5 for holding the balls 4 is disposed. The inner joint member 3 is provided with a spline hole 10 on the inner periphery thereof 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 a boot (not shown), and grease as a lubricant is enclosed inside the joint.

The ball 4 is accommodated in the pocket 5 a of the retainer 5. The spherical outer peripheral surface 12 of the cage 5 slidably fits on 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 It fits freely and is guided.

The spherical inner circumferential surface 6 of the outer joint member 2 and the spherical outer circumferential surface 8 of the inner joint member 3 both have a curvature center 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 alternate long and short dashed lines.

The track groove 7 of the outer joint member 2 will be described based on FIGS. 2a and 2b. 2a is a longitudinal cross-sectional view of the outer joint member of FIG. 1a, and FIG. 2b is a right side view of FIG. 2a. As shown in FIG. 2a, the track groove 7 of the outer joint member 2 is composed of a first track groove 7a located on the back side of the outer joint member 2 and a second track groove 7b located on the opening side. . 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 axially offset (offset amount f) from the joint center O toward the back side.

An intersection point of a plane P including the joint center O at a working angle of 0 ° and orthogonal to the joint axis N-N and the orbital center line Xa of the first track groove portion 7a is D. An angle formed by a straight line connecting the intersection D and the curvature center O1 and a straight line connecting the intersection D and the joint center O is an 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 so as to approach the joint axis N-N toward the opening side of the outer joint member 2. The track center line Xa of the first track groove 7a and the track center line Xb of the second track groove 7b are smoothly connected at the connection point B.

The track groove 9 of the inner joint member 3 will be described based on FIGS. 3a and 3b. Fig. 3a is a longitudinal sectional view of the inner joint member of Fig. 1a, and Fig. 3b is a right side view of Fig. 3a. As shown in FIG. 3a, the track groove 9 of the inner joint member 3 comprises a first track groove 9a located on the opening side of the outer joint member 2 and a second track groove 9b located on the back side. . 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 axially offset (offset amount f) from the joint center O toward the opening side.

Similar to the first track groove 7a of the outer joint member 2 described above, the plane P including the joint center O at a working angle of 0 ° and the track center of the first track groove 7a orthogonal to the joint axis N-N Let E be the point of intersection of the line Xa. An angle formed by a straight line connecting the intersection point E and the curvature center O2 and a straight line connecting the intersection point E and the joint center O is an offset angle η.

The track center line Yb of the second track groove portion 9b is linear, and is inclined at an inclination angle β so as to approach the joint axis N-N toward the back side of the outer joint member 2. 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 a connection point C.

The offset amount f of the first track groove portions 7a and 9a of the outer joint member 2 and the inner joint member 3, the offset angle η, 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 強度 and the inclination angle β is as follows in order to obtain the effects of low heat buildup, strength and durability at high operating angles. It is set to.
η <β <15 °, η 5 5 °
Here, η = sin ⁻¹ (f / R).

The reason for setting the above relationship 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 lost. Further, the force acting on the cage 5 at the high operating angle is reduced, and low heat buildup is obtained, and the strength deterioration of the cage 5 due to the biting in of the spherical edges of the outer joint member 2 and the inner joint member 3 is prevented. be able to. When the inclination angle β is 15 ° or more, the track groove depth at the opening end of the second track groove portion 7b of the outer joint member 2 becomes too shallow, so that the strength and durability at the high operation angle decrease.

The cage is shown in FIGS. 4a and 4b. FIG. 4a is a longitudinal sectional view of FIG. 1a cage, and FIG. 4b is a transverse sectional view taken along line AA of 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 holder 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 pillar 5b is formed between the 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 based on FIGS. 5a to 6b. In summary, when the fixed constant velocity universal joint 1 of the present embodiment takes an operating angle twice or more the inclination angle β, the ball 4 moves to the opening side at the phase angle of 0 ° of the apex shown in FIG. The direction in which the wedge angle opens 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 direction centering on the phase angle of 0 °, so that the force pushing the ball 5 to the opening side As the number of the heads increases, the force acting on the cage 4 is balanced on the back side and the opening side, and the spherical force is reduced.

A specific description will be given based on FIGS. 5a to 6b. FIG. 5a shows the 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 0 ° and 180 ° open toward the back side of the outer joint member 2. Therefore, all the forces of the ball 4 pushing the retainer 5 are directed to the back side. A large spherical force is generated.

FIG. 5b shows the state of a low operating angle θ1 (for example, about 8 °). The wedge angles δ of all the track grooves 7 and 9 including the phase angles 0 ° and 180 ° open toward the back side of the outer joint member 2 even in the state of the low operating angle θ1. Therefore, all the forces of the ball 4 pushing the retainer 5 are directed to the back side. Here, since the track grooves 7 and 9 and the ball 4 are in contact with each other at a contact angle, the contact point is located on the side surfaces of the track grooves 7 and 9 slightly away from the groove bottoms of the track grooves 7 and 9, In FIGS. 5 a-6 b, the wedge angle δ is illustrated using the groove bottoms of the track grooves 7, 9 for the sake of simplicity. Although the actual wedge angle at the contact point and the illustrated wedge angle δ slightly differ in the size of the angle, the reversal behavior of the opening direction of the wedge angle is the same for both.

FIG. 6a shows the state of the middle operating angle θ2 (for example, about 20 °). The wedge angle δ of all the track grooves 7 and 9 including the phase angles 0 ° and 180 ° open toward the back side of the outer joint member 2 in the state of the middle operation angle θ2 where the operation angle is increased, 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 to the opening side.

FIG. 6b shows the state of 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 of the phase angle 0 ° is reversed and directed to the opening side. Then, when the operating angle is further increased, the direction in which the wedge angle δ of the track grooves 7 and 9 near the phase angle of 0 ° opens is also reversed and directed to the opening side, resulting in the state of the high operating angle in FIG. In this state, the opening direction of the wedge angle of the ball 4 is reversed to the opening side in the circumferential direction range centered on the phase angle of 0 °, so the number of forces by which the ball 4 pushes the retainer 5 toward the opening side is As a result, the force acting on the cage 4 is balanced on the back side and the opening side, and the spherical force is reduced.

The analysis result of the spherical force between the holder | retainer 5 of the fixed constant velocity universal joint 1 of this embodiment and the inner joint member 3 is shown in FIG. The offset angle η of the fixed type constant velocity universal joint 1 according to this embodiment is 5 °, and the inclination angle β is 8 °. The conventional product is an 8-ball Zeppa type constant velocity universal joint. As apparent 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 according to this embodiment has a value in the high operating angle range of the low operating angle range. This value is smaller than the value and is significantly reduced compared to the value of the high operating angle range of the conventional product. Thereby, the heat generation at the high operating angle is suppressed.

As described above, the fixed type constant velocity universal joint 1 according to 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. It can solve the problem of low heat buildup and strength at high operating angles. Specifically, it can be manufactured with the same processing accuracy and cost as conventional Zeppa type constant velocity universal joints and undercut free type constant velocity universal joints, and since the heat generation is reduced at a high operating angle, the life of the joint is improves. In addition, since the force acting on the cage 5 is balanced at the high operating angle, the shear failure mode of the cage column 5b due to the biting of the spherical edge portion of the outer joint member 2 and the inner joint member 3 does not occur, and the strength is improved. improves.

Next, a fixed type constant velocity universal joint according to a second embodiment of the present invention will be described based on 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 center lines 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 first. It differs from the embodiment. The other configuration is the same as that of the first embodiment. The parts having the same functions are given 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 7a of the outer joint member 2 is axially offset (offset amount f1) toward the back side of the outer joint member 2 with respect to the joint center O, and the axis of the joint It is formed in an arc shape with a curvature radius R1 having a curvature center O3 offset in the radial direction (offset amount f2) with respect to N-N.

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

The relationship between 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 in the first embodiment. This becomes the same as the operation and effect of the fixed type constant velocity universal joint of the first embodiment. Therefore, the contents described above for the fixed type constant velocity universal joint of the first embodiment apply mutatis mutandis, and the description will be 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 based on FIG. In the fixed type constant velocity universal joint 1 of the present embodiment, the track center lines 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 center of curvature O5 and O6 of the joint, respectively. The second embodiment differs from the second embodiment in that it is offset to the radially opposite side with respect to -N. The other configuration is the same as that of the second embodiment.

The track center line Xa of the first track groove portion 7a of the outer joint member 2 is axially offset (offset amount f3) toward the back 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 of a curvature radius R2 having a curvature center O5 offset (offset amount f4).

The track center line Ya of the first track groove 9a of the inner joint member 3 is axially offset (offset amount f3) toward the opening 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 of a curvature radius R2 having a curvature center O6 offset (offset amount f4).

A fixed type constant velocity universal joint according to a fourth embodiment of the present invention will be described based on 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 It differs from the first embodiment in that it is performed.

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

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

The fixed type constant velocity universal joint 1 according to each of the embodiments 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 while having high operation. It can solve the problem of low heat buildup and strength at the corner. Specifically, it can be manufactured with the same processing accuracy and cost as conventional Zeppa type constant velocity universal joints and undercut free type constant velocity universal joints, and since the heat generation is reduced at a high operating angle, the life of the joint is improves. In addition, since the force acting on the cage 5 is balanced at the high operating angle, the shear failure mode of the cage column 5b due to the biting of the spherical edge portion of the outer joint member 2 and the inner joint member 3 does not occur, and the strength is improved. improves.

It goes without saying that the present invention is not limited to the embodiment described above, and can be practiced in various forms without departing from the scope of the present invention, and the scope of the present invention And the meaning of equivalents described in the claims, and all changes within the range.

Reference Signs List 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 circumferential surface 7 track groove 7a first track groove 7b second track groove 8 spherical outer circumferential surface 9 track Groove 9a First track groove 9b Second track groove 12 Spherical outer peripheral surface 13 Spherical inner peripheral surface N Joint axis O Joint center O1 Joint center O1 Center of curvature O2 Center of curvature O3 Center of curvature O4 Center of curvature O5 Center of curvature O5 Center of curvature O6 Center of curvature O7 center of curvature O8 Curvature center P Plane R Curvature radius R2 Curvature radius R3 Curvature center Xa Orbital centerline Xb Orbital centerline Y Orbital centerline Ya Orbital centerline Yb Orbital centerline f Offset amount f1 Offset amount f2 Offset amount f Offset f4 offset amount f5 offset amount f6 offset amount β inclination angle δ wedge angle η offset angle θ operating angle

Claims (6)

1. 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 The inner joint member formed opposite to the track grooves of the members, the torque transmitting ball incorporated between the opposing track grooves, and the torque transmitting ball are held and guided by the spherical outer peripheral surface of the outer joint member A fixed type constant velocity universal joint comprising a spherical outer peripheral surface and a cage having a spherical inner peripheral surface guided on 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 (7a) disposed on the back side, and a linear second track groove (7b) disposed on the opening side. And consists of
   The center of curvature of the track center line (Xa) of the first track groove portion (7a) is axially offset toward the back with respect to the joint center (O),
   The track center line (Xb) of the second track groove portion (7b) is formed to be inclined in a direction in which the distance to the axis (N-N) of the joint approaches toward the opening side, and the first track 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) including the joint center (O) at an operating angle of 0 ° and orthogonal to the joint axis (N-N) The fixed type constant velocity universal joint is characterized in that it is formed in mirror symmetry with the track center line (X) of the track groove (7) as a pair of the outer joint members.
2. The inclination angle (β) of the track center line (Xb) of the second track groove (7b) with respect to the axis (N-N) of the joint is characterized in that it is larger than the offset angle ()). Fixed type constant velocity universal joint.
3. The inclination angle (β) of the track center line (Xb) of the second track groove (7b) with respect to the axis (N-N) of the joint is less than 15 °. Fixed type constant velocity universal joint as described in.
4. 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 constant velocity universal joint according to any one of the preceding claims.
5. 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 equal amounts on opposite sides in the axial direction with respect to the joint center (O). The fixed constant velocity universal joint according to any one of 4.
6. The fixed type constant velocity universal joint according to any one of claims 1 to 5, wherein the number of the torque transmitting balls is eight.

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