GB2209380A

GB2209380A - Drive shaft assembly

Info

Publication number: GB2209380A
Application number: GB8820593A
Authority: GB
Inventors: Peter Schwaerzler
Original assignee: Loehr and Bromkamp GmbH
Current assignee: GKN Driveline Deutschland GmbH
Priority date: 1987-09-02
Filing date: 1988-08-31
Publication date: 1989-05-10
Anticipated expiration: 2008-08-31
Also published as: FR2619879A1; DE3729275A1; IT1225143B; JPS6474323A; GB2209380B; FR2619879B1; BR8804431A; GB8820593D0; IT8805208A0

Description

1 GMD/8612OGB1 2209380 DRIVE SHAFT ASSEMBLY This invention relates to a

drive shaft assembly wherein a universal joint is disposed adjacent to a transmission unit. The transmission unit may be a gear unit, e.g. a reduction gear or gearbox for a motor vehicle from which a universally jointed propeller shaft extends to a drive axle, or may be a differential gearing unit from which respective universally jointed half shafts extend to drivable wheels of the vehicle. In other embodiments of the invention, the transmission unit may be a supporting bearing assembly such as is provided as an intermediate support in a vehicle propeller shaft having two parts connected to one another by a universal joint, the supporting bearing assembly being provided adjacent the universal joint.

Drive shaft assemblies with a universal joint disposed adjacent a transmission unit have been proposed wherein a component of the universal joint is integrated in some way with a shaft element extending from the transmission unit. For example, AT-PS 284644 discloses a differential gearing in which output gears of the differential gearing unit form the outer members of respective constant velocity ratio universal joints, the inner members of the joints being connected to output shafts.

It is the object of the present invention to provide a drive shaft assembly with a universal joint adjacent a transmission unit, whose design is simplified and which permits easy assembly. More particularly, the object is to provide a cost effective and light weight drive shaft 2 assembly, for situations where the universal joint has to accommodate only relatively small angles of articulation.

According to the present invention, we provide a drive shaft assembly comprising a transmission unit and, adjacent thereto, a universal joint comprising inner and outer joint members and balls for transmitting torque between the joint members, wherein a shaft element extending from the transmission unit has a portion provided with ball-receiving tracks extending parallel to its axis to form the inner member of the universal joint, and the outer member of the universal joint comprises ball-receiving tracks extending parallel to its axis.

As above referred to, the transmission unit may be either a gear unit, e. g. a gear box or differential unit, or a supporting bearing assembly providing an intermediate support for a propeller shaft.

The invention provides a simple solution to the requirement for integrating a universal joint with a transmission unit. The shaft element readily has a portion provided with ball-receiving tracks to form the inner member of the universal joint. A preferred embodiment of the invention has five ball-receiving tracks in each of the inner and outer joint members. The shaft element may be provided with relatively long ball- receiving tracks, along which the balls can move in use over a distance sufficient to accommodate any required change in length in the drive shaft assembly as a result of the nature and geometry of its installation. Thus if there is another universal joint in the drive shaft assembly, such other joint may be an axially fixed (non-plunging) joint.

V 1 3 Preferably the outer joint member is provided with stops which limit movement of the balls along the ballreceiving tracks therein, so that the balls are held with their centres approximately in a single plane and thereby giving the joint substantially constant velocity ratio properties for small angles of articulation. A cage element may be provided, to hold the balls with their centres in one plane, which cage element may also assist assembly of the joint by holding the balls in the tracks in one of the joint members, to facilitate plug-in fitting of the inner and outer joint members together.

The shaft element, extending into the transmission unit may be of substantially the same diameter as the portion thereof which is provided with the ball-receiving tracks. Alternatively, a portion of a shaft element extending into the transmission unit may be of greater diameter than the portion of the shaft element having the ball-receiving tracks, to provide a locating shoulder. Where the transmission unit is a supporting bearing assembly on the shaft element, the shaft element on the opposite side of such bearing assembly from the portion of the shaft element having the ball-receiving tracks may be either of the same or greater diameter than such portion.

The joint outer member may be connected to a light weight hollow shaft member, the outer joint member being either in the form of a sleeve with open ends or a cup shaped member with one open end.

In the case of a propeller shaft assembly, the shaft element forming the inner joint member may extend beyond the portion thereof having the ball-receiving tracks. The outer joint member may extend beyond the region 4 having the ball-receiving tracks towards the transmission unit. These measures result in a better balance of the masses of the joint members on opposite sides of the ball centre plane, and thus make the propeller shaft assembly less sensitive to radial vibration. Where the shaft element has the extension, it may be tapered in order not to reduce the articulation angle obtainable in the universal joint. The intermediate supporting bearing assembly for a propeller shaft may be of conventional type, having an inner race which is received on the shaft element, and an outer race provided with a resilient suspension arrangement by which it may be suspended relative to the chassis of a motor vehicle.

In an alternative, the shaft element may itself form the inner race of the intermediate supporting bearing assembly, leading to a reduction in size and weight of the assembly.

The invention will now be described by way of example with reference to the accompanying drawings, of which:- Figure 1 is a part-sectional view of one embodiment of drive shaft assembly according to the invention; Figure 2 is a part-sectional view of a further embodiment of drive shaft assembly according to the invention; Figure 3 is a part-sectional view of a further embodiment of drive shaft assembly according to the invention, including a supporting bearing assembly; 1 Figure 4 is a part-sectional view of yet a further embodiment of drive shaft assembly according to the invention including a supporting bearing assembly.

Referring firstly to Figure 1 of the drawings, this shows an assembly including a shaft element 1 which extends from and is supported within a housing 2 of a transmission unit, e.g. a gear box or differential unit. The shaft element extends through an oil seal 3. The shaft element 1 has an end portion which is of substantially the same diameter as the rest of the shaft element and is provided with ball-receiving tracks 4 whose centre lines extend parallel to the axis of the shaft element. The shaft element, in its region having the grooves 4, constitutes the inner member of a constant velocity ratio universal joint.

The universal joint further comprises an outer joint member 8, provided in its interior with ball-receiving tracks 9 whose centre liries are parallel to the axis of the outer joint member and which face the tracks 4 in the inner joint member in opposed pairs. A plurality of balls 5 are disposed one in each facing pair of tracks 4, 9 in the joint members to transmit torque therebetween. The tracks 9 in the outer joint member are relatively shorter than the tracks 4 in the inner joint member, the permissible movement of the balls 5 along the outer joint member tracks 9 being limited in one direction by stops 10 formed in the outer joint member, and in the opposite direction by stops 11 which are fitted into the outer joint member 8, the stops 11 preferably being connected to each other in an annular assembly. The joint further comprises an annular cage element 6 which constrains the balls so that their centres occupy a common plane, the cage 6 having a portion received in an annular groove 7 6 inside the outer joint member with a suitable clearance to permit the cage element 6 to move axially a small distance relative to the outer joint member.

The cage element 6 also serves to hold the balls in the tracks in the outer joint member when the joint is not assembled, i.e. when the inner joint member is not present in the outer member. Fitting of the joint members together is thus facilitated.

The outer joint member is a generally cup shaped component, having a closed end opposite the end from which the shaft element 1 extends. A light weight tubular shaft member 16 is welded to the outer joint member at such closed end. The joint is sealed by a flexible annular sealing boot 12 which is connected to the outer joint member by a sheet metal sleeve or can 13. The opposite end of the boot has an annular lip engaging an annular groove extending around the shaft element 1, being held thereto by a circumferential securing clip 15.

The lower half of Figure 1 illustrates a modification, wherein the shaft element has its portion la, which is supported within the transmission unit, of increased diameter relative to the portion of the shaft element having the tracks 4.

Referring now to Figure 2 of the drawings, this shows a drive shaft assembly of which most parts are identical to the embodiment of Figure 1. The same reference numerals are applied to such parts. This embodiment differs in that the outer joint member 8 is provided with a solid annular extension 17 at its end opposite the end at which the tubular shaft 16 is welded. The extension 17 provides the outer joint member with a 1 0 r 7 1 1 greater mass at the opposite side of the ball centre plane from the shaft 16. The balance of the outer joint member is thus improved, and hence the performance of the universal joint with regard to radial vibrations. In consequence of the provision of the extension 17, a sealing boot 12a and securing sleeve or can 13a of slightly different form from the Figure 1 embodiment are provided.

Referring now to Figure 3 of the drawings, there is shown an intermediate supporting bearing and universal joint assembly for a propeller shaft. The intermediate supporting bearing assembly, indicated generally at 118, comprises a metal sleeve 119 adapted to be held by a suitable part of the frame structure of a vehicle where it is to be used, and carrying by way of an annular elastomeric element 119a, a bearing outer race 120. A shaft element 101 has formed directly thereon a bearing inner race 121, and the bearing further comprises circumferentially spaced balls 122 running in the outer and inner races. At one side of the supporting bearing assembly, the shaft element 101 has a portion of increased diameter which is connected by welding to a tubular shaft member 124.

At the opposite side of the supporting bearing assembly 118, the shaft element 101 has a portion which constitutes the inner member of a constant velocity ratio universal joint, being formed with ball-receiving tracks 104 whose centre lines extend parallel to the rotational axis of the shaft element 101. Preferably there are provided five of such tracks 104. The universal joint further comprises an outer joint member 108 which is in the form of a relatively short annular component having circumferentially spaced internal ball-receiving tracks 8 109 which face the tracks 104 in pairs, a respective ball 105 being engaged in each facing pair of tracks 104, 109. The outer joint member 108 is held between a stop member 110, which leads into a tubular connecting part 126, and a sheet metal stop member 111, the stop members 110, 111 together serving to limit movement of the balls along the tracks 109, constraining the balls so that their centres lie more or less in a common plane and the joint has, for small angles of articulation, substantially constant velocity ratio (homokinetic) properties. The connecting part 126 with its stop member 110, and the stop member 111, with the outer joint member 108 therebetween, are held together by a sheet metal can 113 swaged onto these members. The can 113 also serves to secure one end of an annular flexible sealing boot 112 to the outer part of the universal joint, the opposite end of the boot being held to an annular groove 114 in the shaft element 101 by a securing ring 123.

The connecting part 126 is welded to a light weight tubular shaft part 116. A closure cap 127 pressed into the connecting part 126 seals the universal joint adjacent the connection of the tubular shaft part 116.

Figure 4 shows an intermediate bearing and universal joint assembly of a propeller shaft, whose main parts are the same as those of Figure 3 and are indicated by the same reference numerals. This embodiment differs from Figure 3 in that the shaft element 101, in its portion provided with the ball-receiving tracks 104, has a long extension 125 beyond the length of the tracks 104 which is normally contacted by the balls 105 in use. The extension 125 tapers towards its end. The connection part 126a is correspondingly elongated to accommodate the extension 125. The provision of the extension 125 9 facilitates a plug-in type of assembly of the shaft element 101 constituting the inner joint member into the outer joint member, and the fact that the extension 125 is tapered means that the angle to which the universal joint can articulate is not unduly restricted. Figure 4 also shows the cross-section of the portion of the shaft element 101 having the ball- receiving tracks 104.

Universal joints of the type shown in the above embodiments are the subject of our British patent application 8807625 (2 203 220).

Claims

A drive shaft assembly comprising: a transmission unit; a universal joint adjacent the transmission unit; a shaft element projecting from the transmission unit; the shaft element having a portion provided with ball-receiving tracks extending parallel to its axis to constitute an inner member of the universal joint; the universal joint further comprising an outer joint member having ball-receiving tracks extending parallel to its axis.
2. A drive shaft assembly according to Claim 1 wherein said transmission unit comprises a gear unit.
3. A drive shaft assembly according to Claim 1 wherein said transmission unit comprises a supporting bearing assembly.
4. A drive shaft assembly according to any one of the preceding claims wherein said shaft element comprises a portion supported within the transmission unit and of the same diameter as said portion of the shaft element having said tracks.
5. A drive shaft assembly according to any one of Claims 1 to 3 wherein said shaft element comprises a portion supported within the transmission unit and of a greater diameter than said portion of the shaft element having said tracks.
6. A drive shaft assembly according to Claim 3 wherein said shaft element comprises a portion of increased i 11 1'1 0 1 diameter disposed on the opposite side of the supporting bearing assembly from said portion of the shaft element having said tracks.
7. A drive shaft assembly according to any one of the preceding claims wherein the outer joint member comprises axially spaced stops and the ball-receiving tracks of the outer joint member extend between said stops with a length less than the length of the tracks in said portion of the shaft element.
8. A drive shaft assembly according to Claim 7 wherein the outer joint member comprises a plurality of parts secured together.
9. A drive shaft assembly according to Claim 7 or Claim 8 wherein at least one of said stops comprises a separate member inserted into the outer joint member.
10. A drive shaft assembly according to any one of the preceding claims further comprising a tubular shaft member welded to the outer joint member.
11. A drive shaft according to any one of the.preceding claims wherein the shaft element comprises a further portion extending beyond said portion thereof having the ball-receiving tracks.
12. A drive shaft assembly according to Claim 11 wherein said further portion of the shaft element is tapered.
13. A drive shaft assembly according to any one of the preceding claims wherein said outer joint member comprises a portion extending beyond said ball-receiving tracks thereof, towards the transmission unit.

12
14. A drive shaft assembly according to any one of the preceding claims further comprising a cage element for holding balls in the tracks in one of the joint members.
15. A drive shaft assembly according to Claim 3 or any claim appendant thereto wherein the supporting bearing assembly comprises an inner race provided directly on said shaft element.
16. A drive shaft assembly comprising a gearing unit; a universal joint adjacent the gearing unit, the universal joint comprising inner and outer joint members and a plurality of balls for transmitting torque between the joint members; and a shaft element supported by and projecting from the gearing unit, wherein the shaft element has a portion provided with ball-receiving tracks extending parallel to its axis, to constitute the inner member of the universal joint, and the outer joint member comprises ball receiving tracks extending parallel to its axis.
17. A propeller shaft assembly comprising: an intermediate supporting bearing assembly; a universal joint adjacent the bearing assembly, the universal joint comprising inner and outer joint members and a plurality of balls for transmitting torque between the joint members; and a shaft element supported by the bearing assembly wherein the shaft element has a portion provided with ball-receiving tracks extending parallel to its axis, to constitute the inner member of the universal joint, and the outer joint member comprises ball receiving tracks 30 extending parallel to its axis.

1 C 13
18. A drive shaft assembly substantially as hereinbefore described with reference to Figure 1, or Figure 2, or Figure 3, or Figure 4 of the accompanying drawings.

publ,She:! 198B at The Patent OffICC. SWP House 66 1g 1 be obtained frcr., The Patent Office.

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