WO2011142375A1

WO2011142375A1 - Sliding-type constant-velocity universal joint

Info

Publication number: WO2011142375A1
Application number: PCT/JP2011/060816
Authority: WO
Inventors: 真友上
Original assignee: Ntn株式会社
Priority date: 2010-05-13
Filing date: 2011-05-11
Publication date: 2011-11-17
Also published as: JP2011237017A

Abstract

Provided is a sliding-type constant-velocity universal joint having excellent productivity, wherein it is possible to reduce costs with regard to casting devices. Specifically, disclosed is a constant-velocity universal joint provided with: an outer joint member (11) which is formed with track grooves (16) on the inner diameter surface (15); an inner joint member (12) which is formed with track grooves (18) on the outer diameter surface (17); torque transmission balls (13) which are disposed on a torque transmission ball track formed by means of track grooves (16) of the outer joint member (11) and track grooves (18) of the inner joint member (12) corresponding to track grooves (16); and a cage (14) for holding the torque transmission balls (13). The inner diameter of a cage holding section (22) of the outer joint member (11) is set to be larger than the diameter of a circle which inscribes to a tangent line connecting the adjacent balls (13) on the side of the outer diameter of the joint along the circumferential direction. The shape of the inner diameter of the outer joint member (11) is configured by means of the arcs of the track grooves of the outer joint member (11) and the cage holding section (22) and of a tangent line connecting the arcs and cage holding section (22).

Description

Sliding type constant velocity universal joint

The present invention relates to a sliding type constant velocity universal joint applied to a drive shaft or the like used for a light vehicle, a smaller vehicle, or a special vehicle for leisure and agriculture.

等 Constant velocity universal joints are roughly classified into fixed type constant velocity universal joints and sliding type constant velocity universal joints. The fixed type constant velocity universal joint allows only angular displacement and is used on the wheel side of the drive shaft. On the other hand, the sliding type constant velocity universal joint allows angular displacement and axial displacement, and is used on the differential side of the drive shaft.

As the sliding type constant velocity universal joint, there is a double offset type as described in Patent Document 1, Patent Document 2, and the like. As shown in FIGS. 7 and 8, the double offset type constant velocity universal joint includes an outer joint member 3 in which a plurality of track grooves 2 extending in the axial direction are formed on a cylindrical inner peripheral surface 1, and a spherical outer peripheral surface 4. And an inner joint member 6 formed with a plurality of track grooves 5 extending in the axial direction, and a torque transmission ball 7 interposed between the outer joint member 3 and the inner joint member 6 for transmitting torque. The torque transmission ball 7 is held in the pocket 8 of the cage 9.

The center of curvature O1 of the spherical outer peripheral surface 9a of the cage 9 and the center of curvature O2 of the spherical inner peripheral surface 9b are offset by an equal distance in the opposite directions in the axial direction across the joint center O. In addition, a ring body (round retaining ring) 10 is attached to the inner peripheral surface opening end of the outer joint member 3 as a joint preventing part S (inner joint member 6, cage 9, ball 7, etc.). Yes.

In general, the number of torque transmission balls 7 in a double offset type constant velocity universal joint is 6 or 8, but so far, 3 to 5 which is less than 6 is available. Joints have also been proposed (Patent Documents 3 to 5).

Japanese Patent Laid-Open No. 10-73129 JP 2004-347114 A JP-A-45-2484 JP-A-48-38653 Japanese Patent Laid-Open No. 1-18297

By the way, the outer joint member in the double offset type constant velocity universal joint shown in FIG. 7 and FIG. 8 is generally provided with the outer diameter surface, the inner diameter surface and the track groove simultaneously by hot forging and cold forging. Molding. For this reason, the apparatus (forging apparatus) for shaping | molding was expensive.

The object of the present invention is to propose a sliding type constant velocity universal joint that is excellent in productivity and can achieve cost reduction of a molding apparatus.

A first sliding type constant velocity universal joint of the present invention includes an outer joint member having a track groove formed on an inner diameter surface, an inner joint member having a track groove formed on an outer diameter surface, and a track groove of the outer joint member. A constant velocity universal joint comprising a torque transmission ball disposed in a torque transmission ball track formed by cooperation with a track groove of an inner joint member corresponding to the above, and a cage for holding the torque transmission ball. The inner diameter of the cage holding portion of the outer joint member is set to be larger than the diameter of a circle inscribed in a tangent line connected on the joint outer diameter side of adjacent balls along the circumferential direction. It is constituted by an arc of a track groove of the joint member, an inner surface of the cage holding portion, and a tangent line connecting the arc and the inner surface of the cage holding portion.

A second sliding type constant velocity universal joint according to the present invention includes an outer joint member having a track groove formed on the inner diameter surface, an inner joint member having a track groove formed on the outer diameter surface, and a track groove of the outer joint member. A constant velocity universal joint comprising a torque transmission ball disposed in a torque transmission ball track formed by cooperation with a track groove of an inner joint member corresponding to the above, and a cage for holding the torque transmission ball. The inner diameter of the cage holding portion of the outer joint member is set to be the same as the diameter of a circle inscribed in the tangent line connecting on the joint outer diameter side of the adjacent balls along the circumferential direction. It is constituted by an arc of a track groove of the joint member, the cage holding portion, and a tangent line connecting the arc and the cage holding portion.

According to the first and second sliding type constant velocity universal joints of the present invention, the inner diameter shape of the outer joint member is constituted by a circular arc and a straight line without any step. The number of torque transmission balls is preferably 3 to 5 in the first sliding type constant velocity universal joint, and 5 in the second sliding type constant velocity universal joint.

The outer diameter shape of the outer joint member is substantially similar to the inner diameter shape of the outer joint member, and can be set so that the thickness of the outer joint member is substantially the same over the entire circumference. The outer joint member can be a molded product formed by drawing or squeezing a pipe material, or a molded product by press drawing from a steel plate. The outer joint member is preferably subjected to a thermosetting treatment at least on the inner diameter surface after forming the shape. As the thermosetting treatment, various heat treatments such as induction hardening and carburizing and quenching can be employed.

The cross-sectional shape of the track groove can be a Gothic arch shape that makes an angular contact with the ball. Further, the inner joint member and the shaft protruding from the inner joint member can be an integrally molded product.

The sliding type constant velocity universal joint of the present invention can be used for a constant velocity universal joint for a drive shaft of an automobile or a constant velocity universal joint for a propeller shaft of an automobile.

In the present invention, in the sliding type constant velocity universal joint according to the present invention, the inner diameter shape of the outer joint member is formed with a circular arc and a straight line without any step, so that it is easy to shape the inner diameter surface of the outer joint member. Therefore, it is possible to form an inner surface with high accuracy. In particular, if the thickness of the outer joint member is substantially the same over the entire circumference, it is possible to facilitate the shaping of the outer diameter surface of the outer joint member.

For this reason, if the inner diameter shape of the outer joint member is an arc and a straight line and there is no step, and the thickness of the outer joint member is substantially the same in the entire circumference, the pipe material is drawn or ironed, Alternatively, the steel sheet can be formed by press drawing of the steel sheet, forged, and the choice of manufacturing method is widened. Thereby, the cheapest manufacturing method suitable for the manufacturing region can be selected, and productivity can be improved.

By the way, the contact load between the ball and the track groove due to the torque load generates a contact surface (contact ellipse) between the ball and the track groove due to elastic deformation. In the conventional double offset type sliding type constant velocity universal joint, the track groove of the outer joint member is a finite arc (in the cross section in the radial direction), and when the contact load becomes very large, the contact ellipse becomes large and the contact part becomes It may protrude from the track groove. In this case, the stress concentrates on the end of the ball groove (the corner where the ball groove and the inner diameter are connected), which may cause problems such as peeling. On the other hand, in the present invention, since the track groove of the outer joint member and the inner diameter surface are smoothly connected by a tangent line, stress concentration due to protrusion to the contact portion can be prevented, and problems at high loads can be prevented.

The number of track grooves and cage pockets are determined according to the number of balls. For this reason, by reducing the number of balls from 3 to 5, the number of parts can be reduced, and the outer joint member, the inner joint member, and the processing location of the cage (track groove and cage window) can be reduced. Can do. For this reason, with this sliding type constant velocity universal joint, it is possible to achieve an improvement in productivity and a reduction in production cost by reducing the number of processing steps.

If the outer joint member is subjected to a thermosetting treatment after shape formation, a high-quality constant velocity universal joint can be provided that is excellent in strength. Further, by making the cross-sectional shape of the track groove a Gothic arch shape, the contact state of the ball with the track groove can be stabilized. In addition, if the inner joint member and the shaft are integrally formed, the process of assembling the shaft to the inner joint member can be omitted, and the number of processing steps can be reduced to improve the assembly workability. Moreover, by integrating the inner joint member and the shaft, the ball PCD can be made smaller and more compact.

It is optimal for constant velocity universal joints for automobile drive shafts and constant velocity universal joints for automobile propeller shafts.

It is a cross-sectional view of the first sliding type constant velocity universal joint of the present invention. It is a longitudinal cross-sectional view of the said sliding type constant velocity universal joint. It is a cross-sectional front view of the sliding type constant velocity universal joint. It is a cross-sectional view showing a dimensional relationship between the outer joint member and the inner joint member. It is a cross-sectional view of the second sliding type constant velocity universal joint of the present invention. It is sectional drawing which shows the other shape of a track groove. It is a longitudinal cross-sectional view of a conventional double offset type sliding type constant velocity universal joint. It is a cross-sectional view of the sliding type constant velocity universal joint shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 3 show a double offset type sliding type constant velocity universal joint which is a constant velocity universal joint of the present invention. This sliding type constant velocity universal joint includes an outer joint member 11, an inner joint member 12, a torque transmission ball 13, and a cage 14 as main components.

The outer joint member 11 is formed of a cylindrical body having a substantially equal thickness T on the entire circumference, and track grooves 16 are formed on the inner diameter surface 15 at a pitch of 120 degrees along the circumferential direction. The inner joint member 12 is formed of a block body in which track grooves 18 are formed on the outer diameter surface 17 at a pitch of 120 degrees along the circumferential direction. Further, a shaft 19 is projected from the inner joint member 12 as shown by a virtual line in FIG. In this case, the inner joint member 12 and the shaft 19 are integrally formed products.

The cage 14 is provided with pockets 14c in which the balls 13 are held at a pitch of 120 degrees along the circumferential direction. The center of curvature O1 of the outer peripheral spherical surface 14a of the cage 14 and the center of curvature O2 of the inner peripheral spherical surface 14b of the cage 14 are a joint center O (a straight line passing through the ball center Ob and orthogonal to the joint axis L, and a joint axis L). Are offset by an equal distance on the opposite sides in the axial direction.

By the way, the outer joint member 11 has a shape in which the central portion of the side between the top portions 20 bulges in a convex shape in a triangular shape in which the top portion 20 has a convex round shape. For this reason, the inner diameter portion of the top portion 20 constitutes the track groove 16, and the bulging portion 21 between the top portions 20 constitutes the cage holding portion 22 that holds the outer diameter surface of the cage 14.

As shown in FIG. 4, the inner diameter D1 of the inner surface 22a of the cage holding portion 22 in the outer joint member 11 is a circle C inscribed in a tangent line L1 connecting the arcs C1 of the track grooves of

adjacent balls

13 and 13 along the circumferential direction. Is set larger than the diameter D2. That is, D1> D2. Further, the inner diameter shape of the outer joint member 11 is an arc C1 of the track groove of the outer joint member 11, an inner surface 22a of the cage holding portion 22, and a tangent L2 connecting the arc C1 and the inner surface 22a of the cage holding portion 22. It is composed.

The outer diameter shape of the outer joint member 11 is substantially similar to the inner diameter shape of the outer joint member 11. For this reason, the outer joint member 11 has substantially the same thickness T over the entire circumference. In this embodiment, a notch 30 is provided on the outer diameter surface 17 of the inner joint member 12. As a result, the contact area between the outer diameter surface 17 of the inner joint member 12 and the inner peripheral spherical surface 14b of the cage 14 is reduced, but such a notch 30 may not be provided.

By the way, the outer joint member 11 has a substantially uniform (uniform) thickness T in the radial cross section, and the inner diameter shape is a straight line with an arc and has no step. For this reason, the outer joint member 11 can be formed by drawing or ironing a pipe material or by press drawing from a steel plate. Drawing is a processing method for producing a long material having a target cross-sectional shape by passing a pipe material or wire through a tool (die) having a hole and reducing the tensile diameter while holding the tip. The ironing process is a process in which at least a part of a plate material having a predetermined thickness is squeezed with a tool to reduce the thickness of the squeezed portion. The press drawing is a method in which a metal plate material is supported on a die and the plate material is pressed by a punch while the periphery is pressed by a crease presser.

Further, in the outer joint member 11, after the shape is formed as described above, at least the inner diameter surface 15 is subjected to a thermosetting treatment. As the thermosetting treatment, various heat treatments such as induction hardening and carburizing and quenching can be employed. Here, induction hardening is a hardening method that applies the principle of heating a conductive object by placing Joule heat in a coil through which high-frequency current flows, and generating Joule heat by electromagnetic induction. is there. In addition, carburizing and quenching is a method in which carbon is infiltrated / diffused from the surface of a low carbon material and then quenched.

In the present invention, the inner diameter shape of the outer joint member 11 is composed of a circular arc and a straight line without a step. The shape forming of the inner diameter surface 15 of the outer joint member 11 can be facilitated, and the inner diameter surface can be formed with high accuracy. In particular, if the wall thickness T of the outer joint member 11 is substantially the same over the entire circumference, it is possible to facilitate the shaping of the outer diameter surface of the outer joint member 11.

For this reason, if the inner diameter shape of the outer joint member 11 is an arc and a straight line and there is no step, and the wall thickness T of the outer joint member 11 is substantially the same in the entire circumference, the pipe material is drawn out. Forming can be performed by processing, ironing, or press drawing of a steel plate, and forging can be performed, so that the choice of manufacturing method is widened. Thereby, the cheapest manufacturing method suitable for the manufacturing facility can be selected, and the productivity can be improved.

Further, since the inner joint member 12 and the shaft 19 are integrally formed products, the step of assembling the shaft 19 to the inner joint member 12 can be omitted, and the number of processing steps can be reduced to improve the assembly workability. it can. In addition, by integrating the inner joint member 12 and the shaft 19, the ball PCD can be made smaller and more compact.

Next, FIG. 5 shows another embodiment. In this case, the number of balls 13 is three in the above-described embodiment, whereas the number is five. For this reason, five track grooves 16 are provided on the inner diameter surface 15 of the outer joint member 11, and five track grooves 18 are provided on the outer diameter surface 17 of the inner joint member 12.

The outer joint member 11 is formed of a square cylinder having a regular pentagonal cross section with a convex portion 20 at the top portion 20. Moreover, unlike the said embodiment, the bulging part is not formed in each edge | side between the top parts 20 adjacent to the circumferential direction, but it is made into linear form. The inner diameter portion of the top portion 20 constitutes the track groove 16.

The inner diameter D1 of the inner surface 22a of the cage holding portion 22 in the outer joint member 11 is set to be the same as the diameter D2 of the circle C inscribed in the tangent L1 connecting the arcs C1 of the track grooves of the

adjacent balls

13 and 13 along the circumferential direction. is doing. That is, D1 = D2. Also in this case, the inner diameter shape of the outer joint member 11 is constituted by a tangent L2 connecting the arc C1 of the track groove of the outer joint member 11 and the arc C1 of the adjacent track groove. Here, the tangent line L1 and the tangent line L2 are the same. Also in this case, the outer diameter shape of the outer joint member 11 is substantially similar to the inner diameter shape of the outer joint member 11. For this reason, the outer joint member 11 has substantially the same wall thickness on the entire circumference. *

Even in the sliding type constant velocity universal joint shown in FIG. 5, the inner diameter shape of the outer joint member 11 is composed of a circular arc and a straight line without a step. The wall thickness T of the outer joint member 11 is substantially the same over the entire circumference. Therefore, even the sliding type constant velocity universal joint shown in FIG. 5 has the same effects as the sliding type constant velocity universal joint shown in FIGS.

The number of track grooves 12 and the number of pockets in the cage 14 are determined according to the number of balls. For this reason, by setting the number of balls to 3 to 5, the number of parts can be reduced as compared with general 6 or 8 designs. In addition, the processing locations (track grooves and cage windows) of the outer joint member 11, the inner joint member 12, and the cage 14 can be reduced. For this reason, the improvement of productivity and reduction in production cost can be achieved by reducing the number of processing steps.

In each of the above embodiments, the track bottom shape of each

track groove

16, 18 is a simple arc, but the cross-sectional shapes of the track groove 16 of the outer joint member 11 and the track groove 18 of the inner joint member 12 are shown in FIG. As shown, the ball 13 has a Gothic arch shape that makes an angular contact. The

track grooves

16 and 18 having the Gothic arch shape have two ball contact points P and Q (ball contact angle α) that make angular contact with the ball 13. Such angular contact is preferable in that the contact state of the ball 13 with the

track grooves

16 and 18 is stabilized.

The sliding type constant velocity universal joint configured as described above is most suitable for a constant velocity universal joint for a drive shaft of an automobile and a constant velocity universal joint for a propeller shaft of an automobile.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, in the constant velocity universal joint shown in FIG. 5, D1 = D2. However, D1> D2 may be sufficient. Further, the number of balls 13 may be four. As shown in FIG. 1 and the like, when D1> D2, the difference between D1 and D2 can be set by the outer diameter of the outer joint member 11, the ball diameter, the outer diameter of the inner joint member 12, and the like. The thickness of the outer joint member 11 can be variously changed according to the strength, the material to be used, the outer diameter of the outer joint member 11, the part to be used, and the like.

In the above-described embodiment, the inner joint member 12 and the shaft 19 are integrally formed, but the inner joint member 12 and the shaft 19 may be formed separately and then assembled. Further, when the outer joint member 11 is subjected to thermosetting treatment, the outer diameter surface may be subjected to thermosetting treatment in addition to the inner diameter surface 17. Furthermore, a heat curing process may be performed from the inner diameter surface 17 to the outer diameter surface.

This is a sliding type constant velocity universal joint that allows not only angular displacement but also axial displacement. A ball is used for the torque transmission member. The number of balls is 3 to 5. Optimal for sliding type constant velocity universal joints used for drive shafts and propeller shafts.

11 outer joint member 12 inner joint member 13 torque transmission ball 14 cage 15 inner diameter surface 16 track groove 17 outer diameter surface 18 track groove 19 shaft 22 cage holding portion

Claims

The outer joint member having a track groove formed on the inner diameter surface, the inner joint member having a track groove formed on the outer diameter surface, the track groove of the outer joint member, and the track groove of the corresponding inner joint member cooperated. A sliding type constant velocity universal joint provided with a torque transmission ball disposed on a formed torque transmission ball track, and a cage for holding the torque transmission ball,
The inner diameter of the cage holding portion of the outer joint member is set to be larger than the diameter of a circle inscribed in a tangent line connecting on the joint outer diameter side of adjacent balls along the circumferential direction. A sliding type constant velocity universal joint comprising an arc of a track groove of a member, an inner surface of the cage holding portion, and a tangent line connecting the arc and the cage holding portion.
The outer joint member having a track groove formed on the inner diameter surface, the inner joint member having a track groove formed on the outer diameter surface, the track groove of the outer joint member, and the track groove of the corresponding inner joint member cooperated. A sliding type constant velocity universal joint provided with a torque transmission ball disposed on a formed torque transmission ball track, and a cage for holding the torque transmission ball,
The inner diameter of the cage holding portion of the outer joint member is set to be the same as the diameter of a circle inscribed in a tangent line connecting on the joint outer diameter side of adjacent balls along the circumferential direction. A sliding type constant velocity universal joint comprising an arc of a track groove of a member, an inner surface of the cage holding portion, and a tangent line connecting the arc and the inner surface of the cage holding portion.
The sliding type constant velocity universal joint according to claim 1, wherein the number of the torque transmission balls is any one of three to five.
The sliding type constant velocity universal joint according to claim 2, wherein the number of torque transmission balls is five.
5. The outer joint member according to claim 1, wherein an outer diameter shape of the outer joint member is substantially similar to an inner diameter shape of the outer joint member, and a wall thickness of the outer joint member is substantially the same in the entire circumference. The sliding type constant velocity universal joint according to any one of the above.
The sliding type constant velocity universal joint according to any one of claims 1 to 5, wherein the outer joint member is a molded product formed by drawing or ironing a pipe material.
The sliding type constant velocity universal joint according to any one of claims 1 to 5, wherein the outer joint member is a molded product formed by press drawing from a steel plate.
The sliding type constant velocity universal joint according to any one of claims 1 to 7, wherein the outer joint member is heat-cured on at least an inner diameter surface after forming the shape.
The sliding type constant velocity universal joint according to any one of claims 1 to 8, wherein a cross-sectional shape of the track groove is a Gothic arch shape that makes an angular contact with the ball.
The sliding type constant velocity universal joint according to any one of claims 1 to 9, wherein the inner joint member and a shaft protruding from the inner joint member are integrally formed.
The sliding type constant velocity universal joint according to any one of claims 1 to 10, which is used for a constant velocity universal joint for a drive shaft of an automobile.
The sliding type constant velocity universal joint according to any one of claims 1 to 10, which is used for a constant velocity universal joint for a propeller shaft of an automobile.