GB2083167A

GB2083167A - Universal joint

Info

Publication number: GB2083167A
Application number: GB8125507A
Authority: GB
Original assignee: Loehr and Bromkamp GmbH
Current assignee: GKN Driveline Deutschland GmbH
Priority date: 1980-08-27
Filing date: 1981-08-20
Publication date: 1982-03-17
Also published as: IT8105179A0; IT1194975B; JPS5743023A; DE3032183A1; GB2083167B; IT8107018V0; BR8104724A; FR2489452A1

Abstract

A universal joint, suitable for the steering linkage of a vehicle, has an outer joint member 1 and an inner joint member 3. Torque is transmitted between the outer joint member 1 and inner joint member 3 by means of circumferentially spaced pins 6 which protrude in a radially inward direction from the inner surface of the outer joint member 1 and are received in complementary substantially parallel sided grooves in the inner joint member. The pins 6 may alternatively be integral with outer joint member 1 and the surface of the pins may be part spherical. A method of making the outer member 1 is disclosed wherein a blank having inwardly extending pins is provided and the pins are given a part spherical surface by articulation of a tool corresponding to the shape of the inner joint member 6 (Figures 5 to 10 (not shown)). <IMAGE>

Description

SPECIFICATION Universal joint This invention relates to a universal joint incorporating means for torque transmission between an outer joint member and an inner joint member. In particular, the invention relates to a universal joint suitable for use in the steering mechanism of a motor vehicle.

The joints used in the steering mechanism of a motor vehicle are usually required to transmit a relatively small torque at a low angular velocity. If these joints are required to articulate at relatively large angles, the use of universal joints that are incapable of achieving relatively uniform angular velocity at such large angles of articulation is impractical.

In US patent specification 2910845 is shown a universal joint in which torque is transmitted between inner and outer joint members by three circumferentially spaced balls which are arranged on the inner joint member and which engage in corresponding grooves in the outer joint member. However, this joint is only capable of small angles of articulation.

It is an object of the present invention to provide joint capable of achieving angles of articulation greater than 30". It is a further object of the present invention to provide a joint capable of relatively simple manufacture, which does not require fine tolerances to be maintained and yet which operates smoothly and effectively.

According to the present invention there is provided a universal joint comprising an outer joint member, an inner joint member, and three pins connected to the outer joint member and extending inwardly therefrom to engage in grooves in the inner joint member for torque transmission between said members, wherein each of said grooves has side faces which are planar and parallel to one another, and extends parallel to the longitudinal axis of the inner joint member.

An advantage of an universal joint according to the present invention is that relatively large angles of articulation can be achieved by providing grooves on the inner joint member, even if the outer joint member is of relatively small diameter. Furthermore, since the grooves of the inner joint member extend parallel to the longitudinal axis of the inner joint member, independent axial fixing of the joint is ensured in its articulated condition; and there is therefore no requirement for providing an additional fixing means.

The torque transmitting pins may be formed integrally with the outer joint member. The advantage of this is that it is possible to produce a single-component outer part by a non-cutting forming process. Such a process can be relatively cost effective. The dimensional tolerances required in the joint are such that the forming process is sufficiently accurate.

The pins may, in the region in which they are received in the grooves in the inner joint member, be provided with part-spherical surfaces.

A process for producing the outer joint member according to the present invention comprises providing a blank comprising at least three circumferentially evenly-spaced inwardly extending pins and, by means of a tool corresponding to the shape of the inner joint member, forming a part-spherical surface on each of the pins by articulation of the tool. The articulation of the tool may be effected by rotation of the blank and tool engaged therewith, with their rotational axes inclined to one another.

An advantage of the aforementioned process is that, because of the relatively easy forming method which uses a tool in the shape of a inner joint part, the required contacting surfaces of the torque transmitting pins can be provided with an under cut in the shape of a part-spherical surface, without there being any need for relatively expensive machining operations.

An alternative process for forming the torque transmission pins into the requisite part-spherical shape may be by means of radial pressing by a suitable tool.

Two preferred embodiments of the present invention, and methods for manufacturing such, are illustrated with reference to the accompanying drawings in which: Figure 1 shows a part-sectional view of a universal joint according to the present invention.

Figure 2 shows a section along the line I-I of the joint shown in Figure 1.

Figure 3 shows a part-sectional view of a further universal joint according to the present invention in which the torque transmitting pins are integral with the outer joint member.

Figure 4 shows a sectional view along the line ll-ll of the joint shown in Figure 3.

Figure shows an unfinished blank corresponding to the outer joint member shown in Figure 3.

Figure 6 shows a section on the line Ill-Ill of Figure 5.

Figure 7shows a part-sectional view of an outer joint member shown in Figure 5 and further shows a tool for producing the shape of the torque transmitting pin.

Figure 8 illustrates a torque transmitting pin formed bythetool iilustrated in Figure 7.

Figure 9 shows a sectional view along the line IV-IV of the outer joint part shown in Figure 8.

Figure 10 shows a schematic representation of a tool for forming the part-spherical surfaces on each torque transmitting pin.

Referring firstly to Figures 1 and 2 there is shown a univeral joint with an outer joint member 1 having a bore 2 for receiving a shaft (not shown). Within the outer joint member 1 is received an inner joint member 3 formed at one end of a further shaft.

Torque can be transmitted between the outer member and inner member 3 by means of inwardly extending pins 6, spaced circumferentially around the inner surface of the outer joint member 1. The ends of the pins 6 are received in complementary grooves 4, formed in the inner joint member 3. The grooves 4 are substantially parallel-sided and are parallel to the longitudinal axis 5 of the inner joint member 3.

Each torque transmitting pin 6 is received in a respective bore 7 in the outer joint member 1 and is supported against radial displacement by means of a ring 8 which may be fixed in place by deformation of an edge of the outer joint member.

Each of the torque transmitting pins 6 engage within one of the grooves 4 of the inner joint member 3 to transmit torque. In order to prevent the ingress of dust and dirt into the joint, a convolute seal 10 is fixed at one end to the inner joint member shaft and at its other end to the outer joint member by means of a retaining clip 11.

As shown in Figure 2, each of the torque transmitting pins 6 has a part-spherical outer surface 12 in the direction transverse to the longitudinal direction of the joint. The provision of such part-spherical surfaces 12 ensures a substantially constant tolerance between these pins and the inner joint member when the inner joint member is articulated with respect to the outer joint member during rotation.

In Figure 3 is shown an alternative embodiment to the joint shown in Figure 1, the difference being the provision of the pins 6 as an integral part of the outer joint member 1. In all other respects, this joint is substantially identical to that shown in Figure 1 except for the addition of a dust seal 14 which seals the bore 2 of the outer joint member 1. As can be clearly seen in Figure 4, each of the torque transmitting pins 6 is formed integrally with the outer joint member 1.

The joints described in the two embodiments shown in Figures 1 and 3 can conveniently be assembled by introducing the inner joint member 3 into the outer joint member 1 in an axial direction.

Upon articulation of the joint, the inner joint member 3 becomes locked within the outer joint member 1 and does not require further retaining means if kept in this articulated condition.

A process for the production of the outer joint member 1 is illustrated in Figures 5 to 10. In Figure 5, the outer joint member 1 is formed as a blank having rectangular pins 6 whose cross-section can be seen in Figure 6. A tool 15, shown in Figure 7 is then introduced into the outer joint member 1 and has a contour 16 corresponding to the part-spherical cross-section required of the pins 6. The contour 16 of the tool 15 corresponds substantially to the cross-section of the inner joint part 3 and the required shape of the pin 6 is obtained by a pressing operation using this tool. The final shape of the pins is shown in Figure 8 and 9.

In Figure 10 is shown schematically a production method in which a tool 19 corresponding in shape to the inner joint member is inserted within the outer joint member 1 and articulated and rotated in order to provide the part-spherical surface 12 required on each torque transmitting pin 6. The outer member is carried by a supporting bearing 17, and the tool 19 articulated to the position shown in phantom and driven by drive means 18. Thus, it will be seen that formation of the part-spherical surfaces on each of the pins 6 occurs during rotation of the outer joint member 1.

Claims

1. A universal joint comprising an outer joint member an inner joint member, and three pins connected to the outer joint member and extending inwardly therefrom to engage in grooves in the inner joint member for torque transmission between said members, wherein each of said grooves has side faces which are planar and parallel to one another; and extends parallel to the longitudinal axis of the.

inner joint member.

2. A universal joint according to Claim 1 in which said pins are integral with said outer joint member.

3. A universal joint according to Claim 1 or Claim 2 in which said pins are part-spherical in the region in which they are received in said grooves.

4. A method of producing the outer member of a universal joint according to Claim 2 or Claim 3, comprising the steps of providing a blank comprising at least three circumferentially evenly-spaced inwardly extending pins and, by means of a tool corresponding to the shape of the inner joint member, forming a part-spherical surface on each of the pins by articulation of the tool.

5. A method according to Claim 4 wherein said blank and tool engaged therewith are rotated with their rotational axes inclined to one another.

6. A method of producing an outer joint member according to Claim 2 or Claim 3 in which said torque transmitting pins are provided with a part-spherical surface by radial pressing.

7. A universal joint substantially as hereinbefore described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

8. A universal joint substantially as hereinbefore described with reference to and as shown in Figure 3 and 4 of the accompanying drawings.

9. A method of producing a universal joint, substantially as hereinbefore described with reference to and as shown in Figures 5 to 9, or Figure 10, of the accompanying drawings.