GB1578336A

GB1578336A - Propeller shaft assemblies incorporating universal joints

Info

Publication number: GB1578336A
Application number: GB19471/76A
Authority: GB
Original assignee: GKN Transmissions Ltd
Current assignee: GKN Automotive Ltd
Priority date: 1976-05-12
Filing date: 1976-05-12
Publication date: 1980-11-05
Also published as: ES458727A1; JPS531743A; BR7703087A; DE2721098A1; FR2351311A1; NL7705290A; SE7705510L; FR2351311B1; IT1086326B; BE854527A

Description

(54) IMPROVEMENTS RELATING TO PROPELLER SHAFT ASSEMBLIES INCORPORATING UNIVERSAL JOINTS (71) We, GKN TRANSMISSIONS LIMITED, a British Company, of Chester Road, Erdington, Birmingham B24 ORB, West Midlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to propeller shaft assemblies incorporating universal joints each universal joint (hereinafter referred to as being of the kind specified) comprising main members respectively to which and from which the driving and driven torques are transmitted when the joint is in use, and a connecting means operative between the main members for transmitting the torque therebetween whilst permitting of universal movement. The joint may be of the Hookes type in which case each of the main members is in the form of a yoke member having a pair of laterally spaced axially projecting yoke arms joined at one pair of corresponding ends by a connecting portion, and the connecting means comprises a connecting member pivotally connected to respective pairs of yoke arms about pivotal axes mutually perpendicular to each other and to a common axis of the yoke members (when the joint is in the straight or aligned position).

Another form of universal joint of the kind specified to which the invention is applicable is one wherein the main members respectively comprise inner and outer members formed respectively on their outer and inner surfaces with opposed axially extending trackways and the connecting means comprises balls each of which is received partly in a trackway of the inner member for transmitting torque between these members.

An assembly of two propeller shafts joined by a universal joint of the kind specified may be used for transmitting torque from the engine of a motor road vehicle to a rear axle via a differential gear incorporated in the rear axle assembly, and the practice heretofore has been to sup port the assembly at a position interme diate its ends by means of a bearing which in turn is supported from the body or chassis of the vehicle.

In a typical arrangement the support bearing employed has been a ball bearing having an inner raceway of annular form mounted on a specially designed terminal portion of one of the two propeller shafts.

This terminal portion has comprised a stub shaft which at one end has an axially projecting flange of the same diameter as the tubular member which comprises the major portion of the propeller shaft and such flange has been welded to this tubular member. At its other end the stub shaft has been splined externally to co-operate with an internally splined socket afforded by one of the members of the universal joint to which the propeller shaft has been required to be connected. Intermediate the axially projecting flange and the externally splined part the stub shaft has been formed with a seating of a diameter which is intermediate the external diameter of the splines and the external diameter of the axially projecting flange, such seating serving to receive the inner raceway of the ball bearing.

Additionally, the terminal portion of the propeller shaft has been provided with means for preventing its withdrawal from the internally splined socket, such means comprising either 2 screw-threaded stud which can pass through an opening in the inner end wall of the socket for receiving a securing nut on the other side of such end wall, or a groove for receiving a circlip which co-operates with a shoulder presented by the socket at the inner end of the splines.

This construction involves considerable complexities both as to the number of manufacturing operations required to produce the terminal portion of the propeller shaft and secure it to the tubular member thereof, and in assembly of the propeller shaft with the member of the universal joint concerned.

The principal object of the present invention is to provide a simplified construction which will reduce manufacturing cost.

According to the invention, we provide a universal joint and propeller shaft assembly, comprising two propeller shafts the inner ends of which are connected to a universal joint of the kind specified, wherein a support bearing is carried at or adjacent the junction between one of said propeller shaft members and one of the main members of the universal joint, the support bearing being carried on a seating provided on said one main member of the universal joint.

The seating may receive an annular member forming the inner raceway of the bearing and such may be secured in position in any suitable manner, for example by locating against an axial shoulder and being secured against axial withdrawal by a circlip or other fastening element.

Alternatively, however, the seating itself may form the inner raceway of the bearing, the latter further comprising an outer raceway and intermediary balls or rollers spaced apart circumferentially of and engaged between the raceways.

The main members of the universal joint, because of the duty which they have to perform, are ordinarily formed of a material of a higher grade, e.g. a higher carbon steel, than the material utilised for the construction of the propeller shaft, e.g.

lower carbon steel, and consequently the provision on one of the main members or the seating makes use of suitable grade material which is intrinsically present, as distinct from having to provide a terminal portion of the propeller shaft of higher grade material suitable to provide the seating for the bearing, as was formerly the case. Consequently an economy is effected in this respect. This is especially the case where the seating actually forms the raceway of the bearing but also has significant advantages in cases where the seating serves to receive a separately formed racewav.

The arrangement enables the zone of support provided by the support bearing to be positioned nearer to the centre of the universal joint about which relative articulation of the two main members take place than was formerly the case when a speci allv designed terminal portion of the propeller shaft provided the seating. Certain forms of universal joint, for example a Hookes type universal joint, do not afford a constant velocity ratio for all positions of rotation when the main members of the joint are not in the "straight" position, and this characteristic results in the generation of radial forces during torque transmission. The support bearing is better able to minimise vibrations and other undesirable effects resulting from these radial forces when it is placed as near as possible to the centre of the universal joint.

The invention will now be described, by way of example, with reference to the accompanying drawings wherein: - FIGURE 1 is a view in side elevation and partly in vertical cross-section through the axis of one embodiment of universal joint in accordance with the invention incorporated in a universal joint and propeller shaft assembly; FIGURE 2 is a view similar to Figure 1 showing a second embodiment.

Referring to Figure 1, the universal joint therein shown is of the Hookes type and includes two main members 10 and 11 which are in the form of yoke members incorporating arms 12, 13 respectively, and connecting portions 14, 15 respectively.

When aligned the main members rotate about a common axis 16 but are movable universally about mutually perpendicular axes 17 and 18 which are coincident with respective oppositely projecting pairs of trunnions of a connecting member 19 engaging in apertures in the yoke arms and carrying bearings providing for the universal movement.

One of the connecting portions of the main members, namely the connecting portion 14 of the yoke member 10, includes an axially projecting portion 20 which has a machined surface 21 extending along the dimension a as marked and which serves as the inner raceway for a support bearing 22. The yoke members are connected to respective propeller shafts 23 and24, for example b) welded joints 23a and 24a the former of which is spaced axially from the machined surface 21.

The support bearing may be of the roller type as illustrated and comprises a cage 25 carrying rollers 26 engaging in a shallow annular groove in an outer race way member 27. The latter is enclosed in a sheet metal housing 28 which is stepped inwardly at each end 29 of the outer raceway member and provided with extensions 30 which in conjunction with the outer raceway member form channels containing lubricant seals 31, one of which engages the cylindrical surface of the connecting portion 14 to the right of the shoulder against which rage 25 locates, and the other of which engages an inner ring 32 which is secured by being a force fit, or in some other suitable manner, on the machined surface 21.

The housing 28 is supported by being bonded or otherwise secured to a member 33 of rubber or other suitable resilient material which in turn is bonded to attachment member such as plate 34 and is made of a cross-sectional shape such as to provide the required degree of constraint against vertical, ]ateral and torsional movements with respect to the axis 16. The plate 34 may project beyond the rubber member and be provided with fixing elements such as studs or bolts or apertures therefor. Member 35 is a tubular metal insert providing a gauging point for measurement of out-of-balance forces.

In the second embodiment parts corresponding to those already described are designated by like references and the preceding description is to be deemed to apply, reference being made to the differences.

The universal joint in this case is of the type wherein one of the main members is a generally cylindrical outer member 40 of cup-shape affording an interior bore in which is disposed a generally cylindrical inner member 41, these members being formed with longitudinally extending trackways 42, 43 respectively in which engage a plurality of circumferentially spaced balls 44 spaced apart and retained in respective apertures in a cage 45. The cage 45 has an inner part-spherical surface 46 contacting the complementary partspherical surface on the inner member 43 and has an outer part-spherical surface 47 which engages the lands of the outer member in between the tracks 42, the centres of the two part-spherical surfaces 46, 47 being off set axially on opposite sides of the centre 18 about which universal movement of the two main members can take place, thereby ensuring that the joint has constant velocity ratio characteristics. The outer member 40 has an extension 20 part of which is machined to provide a surface 21 extending as before along the dimension a and a support bearing 22 is mounted on this surface 21 in the manner previously described for the embodiment shown in Figure 1.

Both members of the joint are connected to respective propeller shafts 23 and 24, the latter, however, in this case having an extension 24b which plugs into the interior bore afforded by the inner member 41. The extension 24b has external splines engaging with the spaces between internal splines in the internal bore of the member 41.

The joint incorporates a sealing member 48 of rubber or other resilient material closing the annular mouth of the space defined between the inner and outer members.

One of the advantages of utilising the machined seating surface 21 as the inner raceway of the bearing is that it enables reduction to be effected in the overall diameter of the support bearing. This is advantageous in many cases where the invention is applied to propeller shafts running in tunnels or near the underside of the floor of automotive vehicles.

It is to be understood, however, that in both embodiments a separate raceway member could be provided as part of the support bearing, e.g. an extension of member 32, which would then be a force fit or otherwise secured on the extension 20 of the main member of the universal joint.

Further, it will be understood that the invention is not confined to universal joints of the Hookes type or the constant velocity type having inner nad outer members formed with opposing trackways for receiving balls as described above. It may be applied to other forms of universal joint such as those known as bi-pode or tri-pode joints in which a generally cupshaped outer main member has internal grooves or recesses for receiving rollers carried on radially projecting stubs of an inner main member of the joint.

WHAT WE CLAIM IS:- 1. A universal joint and propeller shaft assembly, comprising two propeller shafts, the inner ends of which are connected by a universal joint of the kind specified, wherein a support bearing is carried at or adjacent the junction between one of said propeller shaft members and one of the main members of the universal joint, the support bearing being carried on a seating provided on said one main member of the universal joint.

2. An assembly according to claim 1 wherein the seating receives an annular member forming an inner raceway of the bearing, and there is provided means for securing such inner raceway in position.

3. An assembly according to claim 1 wherein the seating itself constitutes an inner raceway of the bearing, the bearing further comprising an outer raceway and intermediate balls or rollers spaced apart circumferentially of/and engaged between the raceways.

4. An assembly substantially as herein before described with reference to and as shown in figure 1, or figure 2, or figure 3 of the drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. other of which engages an inner ring 32 which is secured by being a force fit, or in some other suitable manner, on the machined surface 21. The housing 28 is supported by being bonded or otherwise secured to a member 33 of rubber or other suitable resilient material which in turn is bonded to attachment member such as plate 34 and is made of a cross-sectional shape such as to provide the required degree of constraint against vertical, ]ateral and torsional movements with respect to the axis 16. The plate 34 may project beyond the rubber member and be provided with fixing elements such as studs or bolts or apertures therefor. Member 35 is a tubular metal insert providing a gauging point for measurement of out-of-balance forces. In the second embodiment parts corresponding to those already described are designated by like references and the preceding description is to be deemed to apply, reference being made to the differences. The universal joint in this case is of the type wherein one of the main members is a generally cylindrical outer member 40 of cup-shape affording an interior bore in which is disposed a generally cylindrical inner member 41, these members being formed with longitudinally extending trackways 42, 43 respectively in which engage a plurality of circumferentially spaced balls 44 spaced apart and retained in respective apertures in a cage 45. The cage 45 has an inner part-spherical surface 46 contacting the complementary partspherical surface on the inner member 43 and has an outer part-spherical surface 47 which engages the lands of the outer member in between the tracks 42, the centres of the two part-spherical surfaces 46, 47 being off set axially on opposite sides of the centre 18 about which universal movement of the two main members can take place, thereby ensuring that the joint has constant velocity ratio characteristics. The outer member 40 has an extension 20 part of which is machined to provide a surface 21 extending as before along the dimension a and a support bearing 22 is mounted on this surface 21 in the manner previously described for the embodiment shown in Figure 1. Both members of the joint are connected to respective propeller shafts 23 and 24, the latter, however, in this case having an extension 24b which plugs into the interior bore afforded by the inner member 41. The extension 24b has external splines engaging with the spaces between internal splines in the internal bore of the member 41. The joint incorporates a sealing member 48 of rubber or other resilient material closing the annular mouth of the space defined between the inner and outer members. One of the advantages of utilising the machined seating surface 21 as the inner raceway of the bearing is that it enables reduction to be effected in the overall diameter of the support bearing. This is advantageous in many cases where the invention is applied to propeller shafts running in tunnels or near the underside of the floor of automotive vehicles. It is to be understood, however, that in both embodiments a separate raceway member could be provided as part of the support bearing, e.g. an extension of member 32, which would then be a force fit or otherwise secured on the extension 20 of the main member of the universal joint. Further, it will be understood that the invention is not confined to universal joints of the Hookes type or the constant velocity type having inner nad outer members formed with opposing trackways for receiving balls as described above. It may be applied to other forms of universal joint such as those known as bi-pode or tri-pode joints in which a generally cupshaped outer main member has internal grooves or recesses for receiving rollers carried on radially projecting stubs of an inner main member of the joint. WHAT WE CLAIM IS:-

1. A universal joint and propeller shaft assembly, comprising two propeller shafts, the inner ends of which are connected by a universal joint of the kind specified, wherein a support bearing is carried at or adjacent the junction between one of said propeller shaft members and one of the main members of the universal joint, the support bearing being carried on a seating provided on said one main member of the universal joint.