GB2249818A

GB2249818A - Hookes universal joints

Info

Publication number: GB2249818A
Application number: GB9123897A
Authority: GB
Inventors: Harald Papke; Wilfried Gille; Ditmar Klischat; Dieter Heier; Gregor Patzulla; Gerd Sehlbach
Original assignee: GKN Cardantec International GmbH
Current assignee: GKN Driveline International GmbH
Priority date: 1990-11-16
Filing date: 1991-11-11
Publication date: 1992-05-20
Also published as: ITMI912954A0; GB9123897D0; IT1251737B; FR2669696A1; ITMI912954A1

Abstract

A Hookes universal joint has at least one of the arms (7) of its cross-member (6) supported in a bearing bush (14) by radial bearing means (11) and axial bearing means (19), the axial bearing means having associated therewith a supporting ring (24) which is resilient in order to adjust itself automatically under load and improve the load distribution in the axial bearing means. The supporting ring preferably defines an internal chamber (25) filled with an incompressible medium such as oil or grease, the quantity of such medium in the chamber being variable in order to adjust the axial bearing means. <IMAGE>

Description

Title: HOOKES UNIVERSAL JOINTS Description of Invention This invention relates to a Hookes universal joint comprising a crossmember whose four arms, each extending at right angles to the adjacent arms, are supported in respective bearing bushes by radial bearing means and axial bearing means, the bearing bushes of two arms with a common axis being held by respective arms of one drive member and the bearing bushes of the other two arms being held by respective arms of another drive member. When we refer to "radial" and "axial" bearing means, these terms relate to orientations relative to the longitudinal axis of the arm in question, rather than to an axis or axes about which the joint transmits torque in use.

It is known in Hookes universal joints of the kind above set forth to arrange the axial bearing means for each arm of the cross-member either directly between the end face of the arm and the base of the bearing bush, or between a collar of the bearing bush and a shoulder of the cross-member at the root end of the arm. When the joint is transmitting torque, the arms of the drive member are subject to elastic deformation, the bore in each arm of the drive member is subject to deformation, and the arms of the cross-member bend. Such influences, and unavoidable play in the bearing means, cause the contact surface of the crossmember for the axial bearing means to tilt, and in consequence lead to an uneven distribution of load in the axial bearing means.

It is the object of the present invention to provide a Hookes universal joint in which the load distribution in the axial bearing means is rendered as uniform as possible.

In accordance with the invention, the above object is achieved in that the axial bearing means of at least one of the arms of the cross-member has associated therewith a supporting ring which is resilient, to adjust itself automatically under load.

The advantage of the invention is that the supporting ring, by virtue of being able to deform resiliently, can adapt to load conditions in the axial bearing means and thus achieve a more uniform load distribution in the axial bearing means.

Preferably the axial bearing means of two arms of the cross member, at right angles to one another, have said resilient supporting rings, and it is preferred for the bearing means of all four arms to have such rings.

Preferably the supporting ring, which axially supports the axial bearing means, is elastically deformable under pressure and defines a continuous hollow chamber containing an incompressible medium.

In this way it is possible for the supporting ring to be able to withstand high axial forces but nevertheless adapt to load conditions to ensure an even load distribution in the axial bearing means.

A further advantage of this construction is that the supporting ring may itself be adjustable, e.g. in order to change its thickness, by changing the quantity of incompressible medium contained in the chamber it defines. Such adjustment of the supporting ring may also be used to achieve the required axial position of the cross-member relative to the bearing bush and thus, for example, eliminate any out-of-balance in the joint as a whole. Further, adjustment of the supporting ring may be used to eliminate backlash, and ensure accurate centering of the joint when all four arms of the cross-member have such supporting rings.

The supporting ring may, in the region of contact surfaces thereof, be provided with walls thinner than the rest of the supporting ring. This measure improves the ability of the supporting ring to adapt itself to prevailing conditions in the bearing.

For simple production of the supporting ring, it may be divided in a plane extending radially of it, into two parts, the two parts being joined together at such plane by welding, especially laser or electron-beam welding.

A high degree of deformability of the supporting ring may be achieved if the walls of the hollow chamber which form the contact surfaces of the ring each include, both radially inwardly and outwardly of such contact surfaces, highly flexible wall portions, e.g. corrugated wall portions.

There are two main alternative arrangements for the disposition of the axial bearing means and supporting ring. In a first alternative, the axial bearing means may be disposed between an annular face of a collar provided on the bearing bush and, with the supporting ring interposed, a shoulder provided on the arm of the cross-member.

In a second alternative, the axial bearing means, comprising a bearing race and the supporting ring, may be disposed between an end face of the arm and the base of the bearing bush.

When the axial bearing means and supporting ring is provided at a collar of the bearing bush, the supporting ring may be used to provide further functions. Thus, the supporting ring and/or a seal carrier provided for a main lubricant seal for the bearing means could be provided with annular grooves which, together, form a labyrinth type of secondary seal.

The hollow chamber of the supporting ring may be connected to at least one conduit closed by a valve, for the admission of the incompressible medium to the chamber of the supporting member. The incompressible medium is preferably oil or grease.

The invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 is an elevation, partly sectioned, of a propeller shaft having Hookes universal joints which may be joints according to the invention; Figure 2 is a section on the line A-A of Figure 1, through one of the Hookes universal joints; Figure 3 is a section through a bearing assembly of a Hookes universal joint, according to a first embodiment of the invention; Figure 4 shows an alternative embodiment of the invention; Figure 5 shows yet a further embodiment of the invention.

Referring firstly to Figure 1 of the drawings, this shows a propeller shaft assembly indicated generally at 1, comprising two Hookes universal joints 2 and a length-adjustable shaft part 3 therebetween. The shaft assembly 1 may be used in the drive line of a machine or of vehicles, but the present invention is particularly, although not exclusively, applicable to the Hookes universal joints of heavy propeller shaft assemblies such as are used in heavy engineering, for example in rolling mill drives.

Each of the Hookes universal joints 2 comprises two yokes or drive members 4, one of which is flanged and the other of which has a spigot for connection to the respective part of the length-adjustable connecting part 3 of the shaft assembly. In each joint, the two drive members 4 are connected to one another by a cross-member 6 which has four arms 7 at right angles to one another, one pair of arms with a common axis 8 and the other pair with a common axis 9. The arms 7 are received in bearing assemblies, to be described in more detail hereafter, in bores 13 of arms 5 of the drive members, the arms having detachable end caps to enable the bearing bushes to be fitted therein.

Thus the two drive members 4 of each joint are connected together for torque transmission and articulation relative to one another.

Figure 3 shows the bearing assembly by which one of the arms 7 of the cross-member 6 of the joint is supported in an arm 5 of a drive member 4 of a joint. The axis 8 or 9 of the visible arm 7 of the cross-member and its aligned opposite arm (not shown) is indicated by a chain-dotted line. The arm 7 is received in a bearing bush 14 which in turn is received in aperture 13 in the arm 5, with the interposition of radial bearing means 11 comprising a number of bearing rollers 12 which run on the external cylindrical surface 10 of the arm 7 and engage the internal cylindrical surface of the bearing bush. Axial bearing means indicated generally at 19 is also provided to withstand axial loads between the arm 7 and bearing bush 14. Different embodiments of axial bearing means are shown in Figures 3, 4 and 5 of the drawings.

In Figure 3, the bearing bush 14 has a collar 15 with an abutment surface 16 supported on a support surface 18 of the drive member arm 5. An intermediate contact disc could, if required, be interposed between the surfaces 16, 18. The oppositely facing surface 17 of the collar 15 provides a running surface for a plurality of bearing members comprising rollers 21 which are located in respective apertures in a cage and, opposite the surface 17, are supported on a bearing surface 22 of a bearing ring 20. The bearing ring 20, in turn, is axially supported on one of two oppositely facing contact surfaces 27 of a supporting ring 24. The other contact surface of the supporting ring engages a shoulder 32 provided on the cross-member 6 at the root of the arm 7.

The supporting ring 24 comprises two ring parts 24a, 24b contacting one another in a plane R extending radially of the ring. The two parts 24a, 24b are connected to one another by laser or electron-beam welding. Between the two parts of the supporting ring, a hollow chamber 25 is defined, the chamber 25 extending throughout the supporting ring around the arm 7. Radially inwardly and outwardly of the contact faces 27 of the supporting ring, the walls 28 thereof are relatively thin so as to be resilient and deflectable, and are formed as corrugations, defined by annular grooves 30 at the exterior of the supporting ring and annular indentations 31 in its interior adjoining the hollow chamber 25. The hollow chamber is connected by a conduit 33 to a filling valve 34, the hollow chamber being filled with an incompressible medium for example oil or grease which may be under pressure.

When pressure is applied to the hollow chamber 25, the contact faces 27 of the supporting ring move apart so that the cross-member 9 of the joint, by way of its shoulder 32, is supported on the arm of the driving member 4 with the intermediary of the axial bearing means 19 and the shoulder 15 of the bearing bush 14.When the universal joint is transmitting torque, the load in the axial bearing means 19 is uniformly distributed around the circumference of the bearing means, as a result of the possibility of automatic adjustment of the orientation of the bearing ring 20 due to the resilience of the supporting ring 24. Furthermore, by increasing the pressure of the medium in the hollow chamber of the supporting ring, it is possible to achieve change in overall thickness of the supporting ring to adjust the play in the axial bearing means 19 or to centre the position of the cross-member 6 relative to the drive member of the joint.

The supporting ring 24 has further functions. It has a radially outwardly extending portion 37 defining an annular groove 35 to form a labyrinth seal with a seal carrier member 36 of complementary annular projection and groove shape, so as to provide a secondary seal or pre-seal for the bearing means 19 and 11. The seal carrier 36 carries a main seal 38 for the bearing means.

Referring now to Figure 4 of the drawings, this shows a bearing assembly which is somewhat similar to that of Figure 3 and the same reference numerals are applied to corresponding parts thereof. In Figure 4, however, the supporting ring 24 is of somewhat different configuration from the supporting ring in Figure 3 and rests directly on the collar 15 of the bearing bush 14. The axial bearing means 19 is provided adjacent the shoulder 32 of the arm 7.

Furthermore, the seal carrier 36 is associated with the arm 7 and carries a seal 38a engaging the supporting ring 24; the bearing ring 20 carries a further seal 38b engaging the seal carrier 36. The supporting ring 24 and seal carrier 36 are shaped to define together a labyrinth seal in region 37a adjacent the seal 38a.

The supporting ring has a part 24b which centres it relative to the collar 15 of the bearing bush 14.

Referring now to Figure 5 of the drawings, this shows an embodiment wherein the axial bearing means is disposed between an end face 39 of the arm 7 and a base portion 40 of the bearing bush 14. Otherwise, however, the general construction of the bearing assembly is analogous to that above described and the same reference numerals are used for corresponding parts. In comparison with the construction of Figure 3, with reference to the axis 8 of the arm 7, the supporting ring 24 comprises a radially inwardly extending filling conduit 33 which communicates with a filling valve 34 extending axially through a central aperture in the base portion 40 of the bearing bush 14. Otherwise, the design of the hollow chamber 25 and its walls 28, 29; the adjoining wall portions and cavity portions 29, 30, 31, correspond to the construction described with reference to Figure 3 of the drawings. At the open end of the bearing bush 14, the shoulder 15 thereof has an annular protrusion 37c which holds a seal 38 engaging a ring 41 at the root of the arm 7; the protrusion 37c also enters a groove 35 in the ring 41 to form a labyrinth seal as a pre-seal to protect seal 38.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

ClAIMS

1. A Hookes universal joint comprising a cross-member having four arms supported in respective bearing bushes by radial bearing means and axial bearing means, the bearing bushes being held respectively by arms of drive members of the joint, wherein the axial bearing means of at least one of the arms of crossmember has associated therewith a supporting ring which is resilient, to adjust itself automatically under load.

2. A joint according to Claim 1 wherein the supporting ring, which axially supports the axial bearing means, is elastically deformable under pressure and defines a continuous hollow chamber containing an incompressible medium.

3. A joint according to Claim 2 wherein the supporting ring, in the region of contact surfaces thereof, has walls thinner than in remaining regions of the supporting ring.

4. A joint according to Claim 2 or Claim 3 wherein the supporting ring is divided in a radially extending plane into two parts which are connected to one another by welding.

5. A joint according to any one of Claims 2 to 4 wherein, radially inwardly and outwardly of the contact surfaces thereof, the walls of the hollow chamber are followed by flexible wall portions.

6. A joint according to Claim 5 wherein the flexible wall portions are corrugated.

7. A joint according to any one of the preceding claims wherein the axial bearing means is disposed between an annular face of a collar provided on the bearing bush and a shoulder provided on the arm of the cross-member, with the supporting ring interposed between the bearing means and shoulder.

8. A joint according to any one of Claims 1 to 6 wherein the axial bearing means is disposed between an end face of the arm and a base portion of the bearing bush, with the supporting ring interposed between the bearing means and bush base portion.

9. A joint according to Claim 7 wherein the supporting ring and a seal carrier element cooperate to provide a labyrinth seal.

10. A joint according to Claim 2 or any claim appendant thereto wherein the hollow chamber is connected to a filling conduit closed by a filling valve.

11. A joint according to any one of the preceding claims wherein the incompressible medium comprises oil or grease.

12. A joint according to any one of the preceding claims wherein the axial bearing means of two of the arms of the cross-member, at right angles to one another, have said resilient supporting rings.

13. A joint according to any one of Claims 1 to 11 wherein the axial bearing means of all the arms of the cross-member have said resilient supporting rings.

14. A joint substantially as hereinbefore described with reference to Figure 3, Figure 4 or Figure 5 of the accompanying drawings.

15. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.