GB2165620A

GB2165620A - Sliding spline assemblies

Info

Publication number: GB2165620A
Application number: GB08425659A
Authority: GB
Inventors: Leslie George Fisher
Original assignee: BRD Co Ltd
Current assignee: BRD Co Ltd
Priority date: 1984-10-10
Filing date: 1984-10-10
Publication date: 1986-04-16
Also published as: GB8425659D0

Abstract

A sliding spine component wherein the spines have axially spaced circumferentially extending resilient projections 19 on their top surfaces, for taking up production tolerances. The splines have a coating of a low friction plastics material, and the projections are formed in such material by circumferential removal of excess coating material from the top surfaces of the spines so that the projections remain. <IMAGE>

Description

SPECIFICATION Sliding spline assemblies This invention relates to sliding spline assemblies for torque transmission. More particularly, the invention relates to the provision of means whereby production tolerances can be taken up and the possibility of misalignment occurring between the rotary axes of the male and female components of a sliding splined joint is reduced.

Various mechanical devices have been proposed for reducing the possibility of such misalignment occurring in splined joints. However, such devices are expensive and add complexity to a splined joint. It is the object of the present invention to provide a means for overcoming such tolerance problems in a simple and economical manner.

According to the invention, we provide a sliding spline component for torque transmission, comprising a plurality of axially extending splines each having a circumferentially extending top surface, wherein each of at least some of said splines is provided with axially spaced circumferentially extending resilient projections on its top surface.

It is known in a sliding splined joint that one of the components of the joint, usually the male shaft component which fits within the female component, can be provided with a low friction coating of a plastics material such as a suitable grade of nylon. Such a coating material is usually applied in the form of a powder to the component at an elevated temperature, so that the coating material meits and flows to cover the component and remain firmly adhered thereto. According to the invention, said resilient projections are preferably formed of such a coating material.

It will be appreciated that when such a coating material is applied to the component it does not naturally have a uniform thickness and thus excess material must be removed from the component so that the splined joint will operate satisfactorily. This is usually done by a broaching operation, using a broaching tool of a shape which removes excess coating material from the top surfaces and sides of the splines to give the correct dimensions.

According to the present invention, in a method of making a sliding spline component as above set forth, removal of the coating material from the top surfaces of the splines is effected by movement of a tool circumferentially relative to the component, said tool having a shape to leave said projections on the spline top surfaces. The removal of material may be effected in a grinding operation, using a grinding wheel having recesses to form the projections.

The invention will now be described by way of example with reference to the accompanying drawings, of which Figure 1 is a side view, partly in longitudinal section, of a sliding splined joint assembly according to the invention, Figure 2 is a view of the splined shaft component of the assembly of Fig. 1, Figure 3 is a section of the component, on line A-A of Fig. 2.

Figure 4 is an enlarged section of pa?t of the component, Figure 5 is a section on the line B-B of Fig.

4.

Referring firstly to Fig. 1, a splined joint assembly comprises a shaft 10 having an end portion 11 provided with circumferentially spaced axially extending splines 12. The shaft fits within a female splined component or muff 13 with circumferentially spaced axially extending internal splines 40, so that the shaft and muff are connected for torque transmission and relative axial movement. The muff 13 has at one end a yoke 15 of Hookes universal joint, and at the other end a seal 16 engaging the surface of shaft 10 to exclude dirt and retain lubricant in the splined connection. A blanking late 17 with a centrally fitted resilient closure plug 18 closes off the joint yoke end of the muff.

The splined end portion 11 of the shaft 10 is shown alone in Fig. 2, and in Fig. 3 in section of the line A-A of Fig. 2. The splines 12 each have, adjacent their axially spaced end, resilient circumferentially extending projections 19. As shown more particularly in Figs. 3 and 4, the projections 19 extend for substantially the full circumferential width of the top surface of their splines.

The end portion 11 of shaft 10 is coated with a low friction plastics material, for example an appropriate grade of nylon. This coating is indicated at 20 in Fig. 4, on the spline 12. Projection 19 is formed in such coating, so that it is resilient. The configuration of one projection 19 in coating 20 is shown in Fig. 5.

As described above, when the plastics coating has been applied to the splined end portion of the shaft 10, it is necessary for excess such coating to be removed so that the correct fit is obtained between the male and female components of the splined joint. In respect of the side faces of the splines and the valley between them, this is usually done by a broaching tool moved axially relative to the splines. In the case of the top surfaces of the splines, however, the invention provides that excess coating material is removed by a tool moving circumferentially around the splined component, such tool having a shape which leaves the projections 19 in the coating. Such removal of coating may be effected by a grinding process, using a grinding wheel of a width equal to the axial length of splines 12 and having recesses which form the projections 19.

Claims

1. A sliding spline component for torque transmission, comprising a plurality of axially extending splines each having a circumferentially extending top surface, wherein each of at least some of said splines is provided with axially spaced circumferentially extending resilient projections on its top surface.

2. A component according to Claim 1 wherein said splines have a coating of low friction plastics material, and said projections are formed of said material.

3. A component according to Claim 2 wherein said spline component is a male shaft component, adapted to fit within a correspondingly splined female component for torque transmission therewith and axial movement relative thereto.

4. A method of making a component according to Claim 3, comprising coating said plastics material onto said splines and effecting removal of a part thereof from said top surfaces to leave said projections remaining thereon, said removal being effected by movement of a tool having the required shape circumferentially relative to said component.

5. A method according to Claim 4 wherein said removal is effected by a grinding operation.

6. A sliding spline component substantially as hereinbefore described with reference to the accompanying drawings.

7. A method of making a sliding spline component, substantially as hereinbefore described.