JP2008267405A - Tripod type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a spherical roller from coming off from a trunnion journal tip end side without increasing the number of parts. <P>SOLUTION: The tripod type constant velocity universal joint is provided with an outer ring 10 forming axially extending truck grooves 14 at equally separated positions of an inner circumference in a circumferential direction, a trunnion 20 having a trunnion journal 26 radially projecting from the equally separated positions in the circumferential direction and roller assemblies rotatably supported by the trunnion journal 26. The roller assembly consists of the spherical roller 30 of which outer circumferential surface forms a perfect sphere and a plurality of needle rollers 32 arranged between the spherical roller 30 and the trunnion journal 26, and an outer diameter A of a tip end part 28 of the trunnion journal 26 is larger than an inner diameter b of the spherical roller 30. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tripod type constant velocity universal joint, and can be used for power transmission devices such as automobiles and various industrial machines.

  A sliding type constant velocity universal joint that allows angular displacement and axial displacement is used for the drive shaft of the front wheel drive vehicle and the rear wheel drive vehicle of the independent suspension type. As shown in FIG. 4, a conventional general tripod type constant velocity universal joint includes an outer ring 10 as an outer joint member, a trunnion 20 as an inner joint member, and a roller assembly (30, 32) as a torque transmission element. Are the main components.

  The outer ring 10 includes a mouse portion 12 and a stem portion 16, and is connected to one of two shafts to be connected by a spline (or serration, the same applies hereinafter) shaft 18 of the stem portion 16 so as to be able to transmit torque. It has become. The mouse portion 12 has a cup shape opened at one end, and a track groove 14 is formed on the inner periphery, and a side wall of each track groove 14 serves as a roller guide surface.

  The trunnion 20 includes a boss portion 22 and a trunnion journal 26. The boss portion 22 has a spline hole 24 for coupling with the other of the two shafts to be coupled so as to be able to transmit torque. Although only one trunnion journal 26 is shown in FIG. 4, three trunnion journals 26 are arranged at equal intervals in the circumferential direction of the boss portion 22.

  Each trunnion journal 26 carries a roller assembly (30, 32). Each roller assembly includes a spherical roller 30 and needle rollers 32. The needle rollers 32 are interposed between the outer peripheral surface of the trunnion journal 26 and the inner peripheral surface of the spherical roller 30 so as to be able to roll. Therefore, the spherical roller 30 can rotate and move in the axial direction with respect to the trunnion journal 26.

  Conventionally, in a general tripod type constant velocity universal joint, an inner washer 34 and an outer washer 36 are disposed on both axial sides of a needle roller 32 as shown in FIG. The inner washer 34 has a ring shape and is interposed between the boss portion 22 of the trunnion 20 and the end surface of the needle roller 32. The outer washer 36 has a substantially L-shaped cross section, and includes a cylindrical portion extending in the axial direction and a disc portion extending radially inward from one end portion of the cylindrical portion. The other end of the cylindrical portion is bent outward in the radial direction, and the outer diameter of the bent portion is larger than the inner diameter of the spherical roller 30. A circumferential groove 29 is formed near the tip of the trunnion journal 26. A circular circlip 38 is attached to the circumferential groove 29 to restrict the movement of the outer washer 36 toward the front end side of the trunnion journal 26. For this purpose, the inner diameter of the disc portion of the outer washer 36 is smaller than the outer diameter of the circular circlip 38, and the outer diameter of the cylindrical portion is equal to or smaller than the circumscribed circle of the needle rollers 32. The bent portion of the outer washer 36 prevents the spherical roller 30 from falling off to the front end side of the trunnion journal 26.

In addition to the above-described general tripod type constant velocity universal joint, Patent Document 1 discloses a tripod type in which a trunnion journal is provided with a collar surface for receiving the end face of a needle roller, and an inner washer, an outer washer, and a round circlip are eliminated. A constant velocity universal joint is described. That is, as shown in FIG. 5B, the outer peripheral surface of the trunnion journal 26 becomes a track for the needle rollers 32, but collar surfaces 26a and 26b are formed on both sides in the axial direction of the track. The axial movement of the needle roller 32 is restricted by the flange surfaces 26a and 26b. In this case, when the spherical roller 30 moves to the tip of the trunnion journal 26, it is structured to fall off (FIG. 5C). That is, the outer diameter of the tip 28 of the trunnion journal 26 is smaller than the circumscribed circle of the needle rollers 32 and smaller than the inner peripheral surface of the spherical roller 30.
JP 2004-68968 A

  5B, when the unit including the trunnion 20 and the roller assembly (30, 32), that is, the tripod kit is removed from the outer ring 10, the trunnion 20, the spherical roller 30, the needle roller 32 is removed. May break apart. That is, in the conventional structure shown in FIG. 5A, the outer washer 36 does not disassemble because it interferes with the spherical roller 30 even if the spherical roller 30 slides upward in the figure. In the type in which there is no outer washer as shown in FIG. 5B and the collar surfaces 26a and 26b are provided on the trunnion journal 26 to prevent the needle rollers 32 from falling off, the spherical roller 30 is shown in FIG. When sliding upward, the trunnion journal 26 falls off, and each component is disassembled.

  An object of the present invention is to prevent the tripod kit from being disassembled even if the tripod kit is dropped from the outer ring without increasing the number of parts.

  A tripod type constant velocity universal joint according to the present invention has an outer joint member in which a track extending in the axial direction is formed at a circumferentially equal position on the inner circumference, and a trunnion journal projecting radially from the circumferentially equal position. An inner joint member and a roller assembly rotatably supported on each trunnion journal, and the roller assembly is a plurality of spherical rollers having an outer circumferential surface arranged between the trunnion journal and the spherical roller. The outer diameter a of the front end portion of the trunnion journal is larger than the inner diameter b of the spherical roller.

  The front end portion of the trunnion journal may have a perfect circle shape (Claim 2) or a non-circular shape (Claim 3).

  According to this invention, since the spherical roller does not fall off from the front end side of the trunnion journal, the tripod kit will not be disassembled even if the tripod kit falls off the outer ring. Further, in the implementation, it is only necessary to set the dimensional relationship between the outer diameter of the trunnion journal tip and the inner diameter of the spherical roller, so that the number of parts is not increased.

  Embodiments of the present invention will be described below with reference to the drawings. Here, the basic structure of the tripod-type constant velocity universal joint, particularly the outer joint member, is substantially the same as the conventional one already described with reference to FIGS. In the following, the tripod kit will be described exclusively.

  The tripod kit shown in FIG. 1 includes a trunnion 20 as an inner joint member and a roller assembly (30, 32) as a torque transmission element. The trunnion 20 includes a boss portion 22 and a trunnion journal 26, and is coupled to a shaft or the like so as to transmit torque by a spline hole 24 formed in the boss portion 22. The trunnion journal 26 protrudes in the radial direction from the circumferentially divided position of the boss portion 22. The outer peripheral surface of the trunnion journal 26 becomes a cylindrical track for the needle rollers 32 to roll. Wall surfaces on both sides in the axial direction of the track serve as flange surfaces 26a and 26b for receiving the end surfaces of the needle rollers 32 disposed on the track.

  Each roller assembly includes a spherical roller 30 and a plurality of needle rollers 32. The spherical roller 30 has a cylindrical inner peripheral surface and a spherical outer peripheral surface. The needle rollers 32 are cylindrical and are arranged between the outer peripheral surface (track) of the trunnion journal 26 and the inner peripheral surface of the spherical roller 30 so as to be able to roll. A so-called full roller bearing without a cage is configured in which the outer peripheral surface (track) of the trunnion journal 26 is an inner race and the inner peripheral surface of the spherical roller 30 is an outer race. Therefore, the spherical roller 30 can rotate and move in the axial direction with respect to the trunnion journal 26. The outer peripheral surface of the spherical roller 30 is in contact with the roller guide surface of the outer ring 10.

  When the relationship between the outer diameter a of the tip portion 18 of the trunnion journal 26 and the inner diameter b of the spherical roller 30 is a <b, the spherical roller 30 is dropped and the tripod kit (20, 30, 32) is disassembled. Resulting in. Therefore, in order to prevent the tripod kit (20, 30, 32) from being disassembled, a slight interference margin is provided (a> b). If an example is given, let it be interference of about several micrometers to several tens of micrometers. With this setting, even if the spherical roller 30 tries to move to the front end side of the trunnion journal 26, it cannot interfere with the front end portion 18 and move outward, so that disassembly can be prevented.

  In order to assemble the spherical roller 30 to the trunnion journal 26, elastic deformation due to the external force of the spherical roller 30 is used. More specifically, as shown in FIG. 2, the spherical roller 30 is set above the trunnion journal 26, and the needle roller 32 is arranged on the outer periphery of the trunnion journal 26, and the spherical roller 30 is moved to the trunnion journal 26. Assemble the tip portion 28 of the plate. At this time, as shown in FIG. 3B, when an external force is applied to the spherical roller 30 in the direction indicated by the white arrow, the spherical roller 30 swells in the direction indicated by the black arrow, and the tip portion 28 of the trunnion journal 26 The relationship between the outer diameter a and the inner diameter b of the spherical roller 30 is a relationship represented by a ≦ b. In this way, by instantaneously creating the relationship of a <b by elastic deformation, the spherical roller 30 can pass through the tip portion 28 of the trunnion journal 26.

  Here, the cross-sectional shape of the tip portion 28 of the trunnion journal 26 can be assembled even if it is a perfect circle. However, as shown in FIG. It can be carried out. That is, by making the cross-sectional shape of the distal end portion 28 of the trunnion journal 26 into a non-circular shape, for example, an elliptical shape, it is possible to provide a long diameter portion and a short diameter portion. As a result, the external force applied during assembly can be reduced.

  When the cross-sectional shape of the tip portion 28 of the trunnion journal 26 is a non-circular shape, an external force in the direction of the white arrow is applied to the spherical roller 30 as shown in FIG. By elastically deforming the trunnion journal 26, the trunnion journal 26 is elastically deformed in the direction of the black arrow, so that the spherical roller 30 can pass through the tip portion 28 of the trunnion journal 26 and be assembled.

It is sectional drawing of the tripod kit which shows embodiment of this invention. It is sectional drawing of the tripod kit which shows an assembly | attachment process. FIG. 3 is an end view of FIG. 2, (A) shows an assembling process after assembling, and (B) shows an assembling process. It is a longitudinal cross-sectional view of a tripod type constant velocity universal joint. (A) is sectional drawing of the tripod kit which shows a prior art, (B) (C) is sectional drawing of the tripod kit which shows another prior art.

Explanation of symbols

10 outer ring 12 mouse part 14 track groove 16 stem part 18 spline shaft 20 trunnion 22 boss part 24 spline hole 26 trunnion journal 26a, 26b collar face 28 tip part 30 spherical roller 32 needle roller

Claims (3)

  An outer joint member in which a track extending in the axial direction is formed at the circumferentially equally divided position of the inner periphery, an inner joint member having a trunnion journal protruding radially from the circumferentially equally divided position, and each trunnion journal is rotatable. The roller assembly comprises a spherical roller having a spherical outer peripheral surface, and a plurality of needle rollers arranged between the trunnion journal and the spherical roller. Tripod type constant velocity universal joint whose outer diameter at the tip is larger than the inner diameter of the spherical roller.   The tripod type constant velocity universal joint according to claim 1, wherein a cross-sectional shape of the tip portion is a perfect circle.   The tripod type constant velocity universal joint according to claim 1, wherein a cross-sectional shape of the collar portion is a non-circular shape.

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