GB2095147A

GB2095147A - Universal joint

Info

Publication number: GB2095147A
Application number: GB8207864A
Authority: GB
Original assignee: Torrington Co
Current assignee: Timken US LLC
Priority date: 1981-03-19
Filing date: 1982-03-18
Publication date: 1982-09-29
Also published as: SE8201053L; AU8068982A; FR2502035A1; DE3209571A1; BR8201347A

Abstract

A universal joint part (26) is an integral member with a hub (28) and trunnions (30) extending from the hub. The integral member is cold- formed to provide a grain flow path in the trunnions parallel to the trunnion outside surface adapted to engage the rollers (34) of a bearing. A metal blank (58) is placed in a bore (54) of a die (50) (52) which has cavities (56) shaped so that the cold- formed integral universal joint part will have the desired configuration. Pressure is then applied against the metal blank using rams (60) (62) to extrude metal into the die cavities to form a cold-formed, integral universal joint part. <IMAGE>

Description

SPECIFICATION Universal joint This invention relates to universal joints, and more particularly, to a universal joint part having lateral trunnions to which the yokes of the joint are pivoted.

In the past, several types of universal joint hubs and trunnions for joining together two bifurcated members have been manufactured, each with its own disadvantages. There have been several structures produced by forging or casting. To ensure maximum strength in bearing life, the path of the grain flow in the trunnion should be axial and parallel to the line of contact between the bearing rollers and the trunnion. Such a grain flow is not readily producible in a forged or cast part.

Universal joint hubs and trunnions have been manufactured that eliminate the need for costly and less-than-precise machining and grinding of the forged or cast parts. In the past, universal joint parts have been produced by assembling machined and ground trunnions to a cross-drilled hub thereby eliminating the need for grinding or machining the assembled cross. The desired grain flow path is also supplied in the trunnions. These advantages have also been accomplished by welding pre-machined and ground trunnions into a hub configuration. The disadvantages of these structures are the necessity to handle a plurality of component parts, maintaining suitable tolerances of component parts so that accumulation of tolerances of the component parts will still fall within the overall tolerances of the assembled parts, and the necessity to ensure the mechanical integrity of the assembled parts.

An object of the present invention is to provide a universal joint part for interconnecting two bifurcated members, which part is of one-piece construction.

One aspect of the invention is a method of cold- forming a universal joint part in which a metal blank is placed in a bore of a die having cavities shaped so that an integral universal joint part of the desired configuration may be formed in the die and pressure is applied against the metal blank to extrude metal from the metal blank into the die cavities to form a cold-formed, integral universal joint part, said universal joint part being thereafter removed from the die.

The lateral extrusion obtained by this process provides a grain flow path which is parallel to the trunnion outside surface adapted to engage the rollers of a bearing. Therefore, when the trunnions are placed in bearings, the grain flow path is parallel to the line of contact between the rollers of the bearings and the trunnions. This provides fora 10:1 improvement in bearing life and provides maximum strength at the hub-trunnion junction.

Another aspect of the invention is a universal joint part comprising an integral member having a hub and trunnions extending from the hub, said integral member having been cold-formed to provide a grain flow path in the trunnions parallel to the trunnion outside surface adapted to engage the rollers of a bearing.

The universal joint part may be formed by placing a metal blank in a bore of a die which has cavities shaped so that the integral universal joint part will have the desired configuration. Pressure is applied against the metal blank to extrude metal from the metal blank into the die cavities to form a cold-formed integral universal joint part. The resulting universal joint part is then removed from the die.

The invention will be further described. by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view showing a preferred embodiment of universal joint part interconnecting a pair of yokes each connected to a rotatable shaft; Fig. 2 is a side view, partly in section, showing a preferred method of forming the universal joint part; Fig. 3 is a view taken along lines 3-3 of Fig. 2 and in the direction of the arrows; Fig. 4 is a side view, partly in section, of the universal joint part with two opposite trunnions placed in roller bearings; and Fig. 5 is a front view, partly in section, showing the universal joint part with all of the trunnions placed in roller bearings.

In the various figures, like parts are referred to by like numbers.

Referring to the drawing, and more particularly to Fig. 1,yoke 10 having arms 12 and 14 connected to a rotatable shaft 1 6 is coupled to a yoke 18 having arms 20 and 22 connected to a rotatable shaft 24 by a universal joint part 26.

Referring to Figs. 1, 4 and 5, the integral universal joint part 26 includes a generallycylindrical hub 28 and a plurality of trunnions 30 extending outwardly from the hub 28. There are preferably four 900 circumferentially-spaced trunnions 30. A bearing 32 is placed over the end of each trunnion 30. The ends of the trunnions 30 are in engagement with rollers 34 (see Figs. 4 and 5) of the bearings 32. The bearings 32 are fitted into bores contained in the arms of the yokes connected to the shafts 1 6 and 24 (see Fig. 1).

The integral universal joint part 26 is made by cold-forming in a manner to provide a grain flow path 40 (see Figs. 4 and 5) in the trunnions 30 parallel to the trunnion outside surface 42 which is adapted to engage the rollers 34 of the bearings 32. Thus, the grain flow paths 40 are established parallel to the line of contact between the trunnion 30 and the bearing rollers 34, ensuring maximum bearing life, and are oriented at the juncture of the trunnion 30 and the hub 28 to ensure maximum strength.

The desired grain flow paths formed by coldforming and the finished, accurateiy, dimensionally-controlled part can be obtained by the method shown in Figs. 2 and 3. Referring to these figures, tooling comprises a split die arrangement consisting of two halves 50 and 52.

Each die half 50 and 52 has a central bore so that when the die halves 50 and 52 are in contact, a bore 54 extends through the combined dies 50 and 52. Each die half 50 and 52 also has four substantially semi-cylindrical cavities 53 (see Fig.

3) 900 spaced apart so that when the die halves 50 and 52 are in contact with one another with the semkcylindrical cavities aligned, there are provided four substantially cylindrical cavities 56 (see Fig.2) which are circumferentially 900 spaced apart.

The cavities 53 conform to a section of the finished universal joint part produced by a plane, perpendicular to the axis of the metal blank 58, and located at the centre line of the trunnions 30.

The bore 54 is provided through both die sections 50 and 52 for positioning the blank 58 and axiallypositioning and supporting the two pressure rams 60and62.

In operation the two die sections 50 and 52 are moved into contact with one another and are maintained fixed by suitable means (not shown).

The metal blank 58 is placed in the bore 54. The pressure rams 60 and 62 are advanced under reduced pressure to a predetermined location to position the metal blank 58 with its axially, perpendicular centre line plane coincident with the mating surfaces of the die sections 50 and 52. The pressure rams 60 and 62 then advance uniformly, exerting sufficient force on the blank 58 to cause the metal of the blank 58 to extrude laterally into the cylindrical cavities 56. The rams 62 and 60 are then retracted, the die sections 50 and 52 separated, and the cold-formed, laterallyextruded universal joint part 26 is removed.

Claims

1. A method of cold-forming a universal joint part in which a metal blank is placed in a bore of a die having cavities shaped so that an integral universal joint part of the desired configuration may be formed in the die and pressure is applied against the metal blank to extrude metal from the metal blank into the die cavities to form a coldformed, integral universal joint part, said universal joint part being thereafter removed from the die.

2. A method as claimed in claim 1 wherein the die comprises a spiit die arrangement of two halves with each half having a bore and four substantially semi-cylindrical cavities 900 spaced apart with the bores and the semi-cylindrical cavities of the two halves aligned to provide four substantially cylindrical cavities and a bore through the combined two halves; and a pressure ram is placed in each die half bore and against the metal blank to extrude the metal into the cylindrical cavities.

3. A universal joint part comprising an integral member having a hub and trunnions extending from the hub, said integral member having been cold-formed to provide a grain flow path in the trunnions parallel to the trunnion outside surface adapted to engage the rollers of a bearing.

4. A universal joint part as claimed in claim 3, wherein the hub is generally cylindrical and there are four 900 circumferentially spaced apart trunnions extending from said hub.

5. A method of cold-forming a universal joint part substantially as herein described with reference to Figs. 2 to 5 of the accompanying drawings.

6. A universal joint part constructed substantially as herein described with reference to and as illustrated in Figs.1,4 and 5 of the accompanying drawings.