JP2008208935A - Tripod type constant velocity joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce manufacturing cost without lowering the static strength and fatigue strength of a driving shaft and a spider. <P>SOLUTION: The spider 18 and the driving shaft 14 are relatively rotated so that one end face 18a of the spider 18 is joined with one end face 14a of the driving shaft 14 with friction pressure contact. A first recessed portion 26 in an approximately circular cross section is formed in one end face 18a of the spider 18. On the other hand, a second recessed portion 28 in an approximately circular cross section is formed in the other end face 18b, and a sealed cavity portion 32 is formed between the first recessed portion 26 of the spider 18 and a third recessed portion 30 of the driving shaft 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tripod type constant velocity joint that connects one transmission shaft and the other transmission shaft, for example, in a driving force transmission section of an automobile.

  Conventionally, in a driving force transmission unit of an automobile, a constant velocity joint that connects one transmission shaft and the other transmission shaft and transmits a rotational force to each axle is used. A triport constant velocity joint capable of absorbing angular displacement and axial displacement is known as a constant velocity joint according to this type of prior art.

  In this triport type constant velocity joint, three trunnions are formed to bulge outward in the radial direction, and include a spider that is serrated (or splined) at the end of the drive shaft. The inner wall is provided so as to slide along a track groove formed along the axial direction.

  In this case, for example, in Patent Document 1, when the teeth on the shaft member side and the teeth on the outer peripheral member side arranged on the outer peripheral side of the shaft member are spline-coupled, the static strength and fatigue strength of the spline shaft are improved, respectively. Therefore, the diameter of the trough of the tooth on the shaft member side is increased to form a diameter-expanded region, and a fitting portion between the tooth on the shaft member side and the tooth on the outer peripheral member side is provided in the expanded diameter region. The idea is disclosed.

JP 2000-97244 A

  The present invention has been made in connection with the technical idea of Patent Document 1 described above, and is a tripod that can reduce the manufacturing cost without lowering the static strength and fatigue strength of the drive shaft and spider. It aims to provide a mold constant velocity joint.

In order to achieve the above-mentioned object, the present invention provides a cylindrical outer member that is provided with a plurality of guide grooves spaced apart from each other at a predetermined interval and extending along the axial direction, and is connected to one transmission shaft. ,
A spider having a plurality of trunnions bulging toward the guide groove and formed in a substantially disc shape;
A ring-shaped roller member that contacts the guide groove and is externally fitted to the trunnion;
A drive shaft coupled to the spider and serving as the other transmission shaft;
With
One end surface of the spider and one end surface of the drive shaft are joined by friction welding by relatively rotating the spider and the drive shaft,
A concave portion is formed on at least a surface to be joined of the spider to which the drive shaft is joined, of both end faces along the axial direction of the spider.

  According to the present invention, a recess is formed at least on one end surface of the spider to which the drive shaft is joined, and the one end surface of the spider and the one end surface of the drive shaft are friction-welded to each other. The spider and the drive shaft are firmly coupled with a coupling force equivalent to that of the conventional serration coupling or spline coupling.

  As a result, in the present invention, the static strength and fatigue strength of the drive shaft and spider are not reduced, and the manufacturing process is simplified because the conventional phase alignment operation is unnecessary. Cost can be reduced.

  In the present invention, a recess is formed on one end surface of the drive shaft that is joined to one end surface of the spider, and a recess formed on one end surface of the spider and a recess formed on one end surface of the drive shaft. A sealed gap is provided, and burrs generated at the time of friction welding are accommodated in the gap and are prevented from escaping to the outside.

  According to the present invention, the following effects can be obtained.

  That is, the static strength and fatigue strength of the drive shaft and spider are not lowered, and the manufacturing cost can be reduced.

  A preferred embodiment of the tripod type constant velocity joint according to the present invention will be described below and described in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 indicates a tripod type constant velocity joint according to an embodiment of the present invention.

  This triport type constant velocity joint 10 is connected to a cylindrical outer cup (outer member) 12 integrally connected to one end of a first shaft (not shown) and an opening, and one end 15 having an enlarged diameter of the drive shaft 14. The inner member is basically constituted by being joined and housed in the hole of the outer cup 12.

  As shown in FIG. 1, three guide grooves 16 a to 16 c are formed on the inner wall surface of the outer cup 12. The three guide grooves 16 a to 16 c extend along the axial direction and are spaced by 120 degrees around the axis. (However, the guide grooves 16b and 16c are not shown).

  A spider 18 made of a substantially disk-shaped block body is firmly joined to one end portion 15 along the axial direction of the drive shaft 14 by friction welding (friction welding) described later. Three trunnions 20a to 20c are integrally formed at intervals of 120 degrees around the bulge axis toward the guide grooves 16a to 16c (however, trunnions 20b and 20c are not shown) is doing).

  Further, an end surface 18a that is a surface to be joined to the drive shaft 14 and extends along the axial direction of the spider 18 has a substantially circular cross section at the center of the flat end surface 18a, as shown in FIG. A first recess 26 is formed. On the other hand, a second recess 28 having a substantially circular cross section with a slightly larger diameter than the first recess 26 is formed at the center of the other end surface 18b of the spider 18 opposite to the one end surface 18a. Is formed.

  The first concave portion 26 and the second concave portion 28 formed on the both end faces 18a and 18b of the spider 18 are formed in a concave shape whose longitudinal sections are curved, respectively, and the first concave portion 26 and the second concave portion 28 are wall portions. Is formed in a non-penetrating state. Moreover, the shape of the first recess 26 and the second recess 28 is not limited to a shape having a curved longitudinal section, and may be a rectangular cross section or a composite cross section.

  The enlarged end portion 15 of the drive shaft 14 is opposed to the first recess portion 26 formed on the one end surface 18a of the spider 18 and has a third cross-section having a substantially circular shape having the same diameter as the inner diameter of the first recess portion 26. A recess 30 is formed. In this case, a sealed gap 32 is formed between the first recess 26 of the spider 18 and the third recess 30 of the drive shaft 14, and a burr is accommodated in the gap 32 as will be described later. Therefore, it is possible to reduce the weight of the entire constant velocity joint.

  As shown in FIG. 5, the end surface 14 a of the drive shaft 14 may be formed on the flat surface 33 without forming the third recess 30.

  A ring-shaped roller member 24 is fitted around the outer periphery of the trunnion 20a (20b, 20c) via a plurality of rolling elements 22. The rolling element 22 may be a rolling bearing including, for example, a needle and a roller.

  The tripart constant velocity joint 10 according to the present embodiment is basically configured as described above. Next, the operation and effects thereof will be described.

  First, the three trunnions 20a to 20c are forged and molded on the outer peripheral surface by a forging molding device (not shown), and the first recess 26 and the second recess are coaxially arranged by an upper punch and a lower punch (not shown). A substantially disc-shaped spider 18 formed with 28 and a drive shaft 14 cut to a predetermined length are prepared.

  In a state where the first recess 26 of the spider 18 and the third recess of the drive shaft 14 face each other using a positioning and holding mechanism (not shown), the one end surface 18a of the spider 18 and the one end surface 14a of the drive shaft 14 Are positioned relative to each other and held in opposition (see FIG. 2).

  Therefore, the spider 18 and the drive shaft 14 are pressurized in a direction approaching each other using a friction welding mechanism (not shown) (see FIG. 3). That is, the spider 18 and the drive shaft 14 are relatively rotated to heat the contact surfaces, and friction welding (friction welding) is performed to heat the joint surfaces by the generated frictional heat. The end surface 18a and the one end surface 14a of the drive shaft 14 are joined to each other.

  At this time, as shown in FIG. 4, a burr 34 is generated in a gap 32 formed by the first recess 26 of the spider 18 and the third recess 30 of the drive shaft 14. 18 is accommodated in a gap 32 formed by being closed at the joint between the drive shaft 14 and the drive shaft 14 and is not exposed to the outside. Therefore, the burr 34 accommodated in the gap portion 32 is reliably prevented from spreading out.

  Further, when the joint surface between the spider 18 and the drive shaft 14 is heated and friction welded, the circumferential width (joint) of the joint surface between the one end surface 18a of the spider 18 and the one end surface 14a of the drive shaft 14 is increased. The surface pressure at the time of friction welding can be easily controlled by setting the surface (between the outer diameter and inner diameter) to be substantially constant.

  As described above, in the present embodiment, the first concave portion 26 and the second concave portion 28 are respectively formed on both end surfaces 18a and 18b of the spider 18 formed in a substantially disc shape, and the one end surface 14a of the drive shaft 14 is formed. A third recess 30 corresponding to the first recess 26 is formed, and the one end surface 18a of the spider 18 and the one end surface 14a of the drive shaft 14 are friction-welded to each other, thereby being equivalent to a conventional serration coupling or spline coupling. The spider 18 and the drive shaft 14 are firmly coupled with each other.

  As a result, in the present embodiment, the static strength and fatigue strength of the drive shaft 14 and the spider 18 are not reduced, and the phase adjustment work and the like as in the conventional method are not required, and the manufacturing process is simplified. Therefore, the manufacturing cost can be reduced.

  In the present embodiment, the first concave portion 26 and the second concave portion 28 are formed on both end surfaces 18a and 18b along the axial direction of the spider 18, but the second concave portion 28 of the other end surface 18b of the spider 18 is formed. The entire other end surface 18b may be a flat surface.

  Next, the operation of the tripart type constant velocity joint 10 will be described.

  When a first shaft (not shown) rotates, the rotational force is transmitted to the inner member via the outer cup 12, and the drive shaft 14 joined to the spider 18 through the trunnions 20a to 20c rotates in a predetermined direction.

  That is, the rotational force of the outer cup 12 is applied to the trunnions 20a to 20c via the roller member 24 that is in surface contact with the guide groove 16a (16b, 16c) and the plurality of rolling elements 22 held in the inner diameter portion of the roller member 24. , The drive shaft 14 rotates via the spider 18.

It is a longitudinal cross-sectional view along the axial direction of the tripart type | mold constant velocity joint which concerns on embodiment of this invention. FIG. 5 is a partial longitudinal sectional view showing a state in which the first recess of the spider and the third recess of the drive shaft are opposed to each other in the manufacturing process of the constant velocity joint shown in FIG. 1. FIG. 2 is a partial longitudinal sectional view showing a state in which the spider and the drive shaft are friction-welded in a state where the spider and the drive shaft are relatively rotated in the manufacturing process of the constant velocity joint shown in FIG. 1. FIG. 2 is a partial longitudinal sectional view showing a state in which burrs are generated when the spider and the drive shaft are friction-welded in the manufacturing process of the constant velocity joint shown in FIG. 1. It is a fragmentary longitudinal cross-section which shows the state which carried out the friction welding of the drive shaft which concerns on the modification with which the one end surface was formed flat, and the said spider.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Triport type constant velocity joint 12 ... Outer cup 14 ... Drive shaft 14a ... One end surface 16a-16c ... Guide groove 18 ... Spider 18a, 18b ... End surface 20a-20c ... Trunnion 22 ... Rolling element 24 ... Roller member 26, 28, 30 ... Recess 32 ... Cavity 34 ... Burr

Claims (2)

A cylindrical outer member that is provided on the inner peripheral surface with a plurality of guide grooves that are spaced apart by a predetermined distance and extend along the axial direction, and is connected to one transmission shaft;
A spider having a plurality of trunnions bulging toward the guide groove and formed in a substantially disc shape;
A ring-shaped roller member that contacts the guide groove and is externally fitted to the trunnion;
A drive shaft coupled to the spider and serving as the other transmission shaft;
With
One end surface of the spider and one end surface of the drive shaft are joined by friction welding by relatively rotating the spider and the drive shaft,
A tripod type constant velocity joint, wherein a recess is formed in at least a surface to be joined of the spider to which the drive shaft is joined, of both end faces along the axial direction of the spider. The constant velocity joint according to claim 1,
A tripod type constant velocity joint, wherein a recess is formed in one end surface of the drive shaft joined to one end surface of the spider.

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