GB2200722A

GB2200722A - Constant velocity universal joints

Info

Publication number: GB2200722A
Application number: GB08802035A
Authority: GB
Inventors: Hans-Heinrich Welschof; Friedhelm John
Original assignee: Loehr and Bromkamp GmbH
Current assignee: GKN Driveline Deutschland GmbH
Priority date: 1987-01-30
Filing date: 1988-01-29
Publication date: 1988-08-10
Anticipated expiration: 2008-01-29
Also published as: GB8802035D0; IT1220451B; GB2200722B; FR2610376A1; IT8805109A0

Abstract

A constant velocity ratio universal joint has one of its joint members connected to a shaft part by a torque transmitting connection which is also axially resilient to permit relative axial movement between the joint member and shaft part. The axially resilient connection may be provided either by one or two resilient diaphragms 14, (107a 108a), Figure 11 or by a perforated resilient sleeve (22) (Figure 6). Various forms of stop elements or guide elements may be provided to limit undesired relative articulation or other misalignment between the joint member and shaft part. The axial resilience of the connection has the effect of preventing transmission of axial vibration, particularly at high frequency, through the universal joint. <IMAGE>

Description

CCNSTANT VELOCITY UNIVERSAL JOINTS This invention relates to constant velocity ratio universal joints, comprising two joint members connected to one another for torque transmission and relative articulation therebetween Such universal joints are widely used in motor vehicle drive lines One problem in motor vehicle drive lines is that of minimising transmission of axial vibrations herein, this being important both in propeller shafts extending longitudinally of vehicles and, especially, in laterally extending drive shafts connected to drivable wheels. Transmission of such vibrations to the body of the vehicle cannot be eliminated merely by incorporating plunging universal joints or splined shaft connections, because such devices stiffen axially when they are transmitting torque.To incorporate rubber couplings or the like is not satisfactory because they are torsionally soft, and do not provide any support against relative radial movement between the parts they connect.

Transmission of axial vibrations can be reduced by utilising plunging constant velocity ratio universal joints designed to have a low resistance to plunge. This is effective particularly at lower vibration frequencies.

At higher frequencies, some vibration is still transmitted. Further, even such constant velocity ratio universal joints stiffen axially under torque transmission, so that more of the vibration can be transmitted therethrough It is the object of the present invention to provide a constant velocity ratio universal joint which has an enhanced axial flexibility for reducing transmission of vibrations According to the present invention, we provide a constant velocity ratio universal joint, comprising two joint members connected to one another for torque transmission and relative articulation therebetween, wherein one of said joint members is connected to a shaft part by resilient means permitting relative axial movement between the joint member and shaft part and providing a torque transmitting connection therebetween.

The joint may be one in which the two joint members are able to undergo relative axial movement (plunge), or may be a non-plunging joint.

Several arrangements of the resilient means are described hereafter In some embodiments, the resilient means comprises a resilient disc or diaphragm (hereinafter called a diaphragm) extending generally radially between the shaft part and joint member. The diaphragm may comprise an annulus of sheet metal, connected at its inner periphery to the shaft part and at its outer periphery to the joint member, the latter being the outer member of the joint In further preferred embodiments of the invention as described hereafter, the resilient means comprises an axially resilient sleeve connected between the shaft part and joint member The sleeve may be provided with apertures so that it is of open-work form to give it the required axial resilience In a universal joint according to the invention, the axially resilient means, of whatever form, does not transmit axial vibrations By various methods it is possible to ensure that the axially resilient means does not bend undesirably, nor suffer under torque loads Where the resilient means comprises a resilient diaphragm, the shaft part and joint member may have stop elements cooper able to limit relative movement in at least one sense therebetween.Such stop elements may limit movement in the sense of relative articulation between the shaft part and joint member, and to prevent the possibility of damage to the diaphragm in use may also prevent excessive axial or torsional movements in the diaphragm At least one resilient, e g rubber or plastics, element may be disposed between the diaphragm and a stop element, and/or between the stop elements Such a resilient element absorbs and damps shocks and impacts, and may be suitable for adjusting the damping characteristics of the constant velocity ratio universal joint In further embodiments, the shaft part and joint member are connected by two axially spaced generally radially extending diaphragms Such use of two diaphragms has the result that the shaft part and joint member are held in alignment with one another, while still having the possibility of friction free relative axial movement Preferably the two diaphragms have radially outer portions which are connected to a rigid axial extension integral with or secured to the joint member The diaphragms may have radially inner portions connected to a rigid shaft part Both diaphragms may be connected between the shaft part and joint member for torque transmission therebetween, in which case each diaphragm transmits approximately half the total torque However, it would be possible for the entire torque to be transmitted through one of the diaphragms, whilst the second diaphragm is subjected to axial and radial forces only A rigid or flexible element may be disposed between the diaphragms, to limit the range of relative axial movement between the shaft part and joint member, and, in the case of a flexible element, to damp such movement at its limits Whether one or two diaphragms are utilised in the universal joint, the or each one preferably comprises an annular element of sheet material, which may be provided with part-circumferential or radial slots to increase its axial flexibility Where radial slots are provided, they may extend to the outermost periphery so that the diaphragm is, in effect, star shaped A further possible embodiment of diaphragm comprises strips of material, e.g. sheet metal, disposed in the manner of the spokes of a wheel Half such strips are subjected to tensile loads during torque transmission Axial flexibility is achieved, combined with a high stiffness in the radial and circumferential directions.

In the case of a resilient means in the form of a sleeve, the sleeve may be provided with square or diamond shaped apertures so that, in effect, the remaining material consists of intersecting helically extending webs, erg at a helix angle offorty-five degrees In a further embodiment, the sleeve may be provided with rows of circumferential slots which are offset circumferentially relative to one another Such slots permit considerable changes in the length of the sleeve It is possible to provide resilient elements of rubber or plastics between the joint member and shaft part connected by the sleeve, and in a further embodiment such a material may be provided in the apertures of the sleeve.

The joint member and/or the shaft part may be provided with rigid stop elements which prevent any bending from occurring in the region of the sleeve For example, a rigid cylindrical supporting sleeve may be disposed inside or outside the torque transmitting sleeve, connected to the joint member or the shaft part and arranged with a small clearance from a stop element on the other part.

Other forms of guiding means may be provided, operative between the joint member and shaft part to prevent undesirably destructive deformation of a diaphragm, sleeve, or whatever form of axially resilient means is utilised For example, sliding bushes, or roller guiding means could be provided. Further, axial and/or torsional stops may be provided, to prevent damage to a flexible sleeve or diaphragm A sealing device may be provided, to prevent access of dirt to the resilient means The invention will now be described by way of example with reference to the accompanying drawings, of which:: Figure 1 is a section through a constant velocity ratio universal joint, illustrating the principle of the invention as put into effect by the practical embodiments described hereafter; Figure 2 is a section through half of a first embodiment of joint according to the invention; Figure 3 is a section as Figure 2, showing a modification thereof; Figure 4 is an axial view of part of the joint of Figure 2 or Figure 3; Figure 5 shows yet a further modification of joint according to the invention; Figure 6 shows the basic principle of a second embodiment of joint according to the invention; Figures 7 and 8 show modifications of the joint of Figure 6; Figure 9 shows four possible embodiments of sleeve incorporated in the joints of Figures 6, 7 or 8; Figure 10 is a section through yet another embodiment of joint according to the invention;; Figure 11 is a section through yet a further embodiment of joint according to the invention; Figure 12 is a section through a final embodiment of joint according to the invention Referring firstly to Figure 1 of the drawings, there is shown a constant velocity ratio universal joint 1 which comprises an inner joint member 2, an outer joint member 6, and a plurality of circumferentially spaced balls 11 therebetween, each ball occupying a pair of opposed grooves in the inner and outer joint members The balls are retained in apertures in an annular cage 12 between the joint members, the arrangement being such that the balls transmit torque between the joint members while permitting relative articulation and axial movement (plunge) therebetween The inner joint member 2 has a splined central bore for receiving a splined end portion of a shaft 5 for torque transmission, the shaft being held in the inner joint member by a spring securing ring 3.

A shaft part 10 terminates in a generally frustoconical outwardly extending bell part 9, leading into a rigid supporting sleeve 8 which extends axially over part of the exterior of the outer joint member 6. A connection for torque transmission between the outer joint member and shaft part 10 is provided by axially resilient means which is illustrated as springs 7, so that the universal joint is able to absorb and not transmit axial vibrations arising in any drive line in which the joint is installed Such axial vibrations cause relative axial movement between the outer joint member 6 and shaft part 10 which is permitted by the springs 7, with a greater freedom for relative axial movement than is provided by the relative plunging movement possible between the inner and outer joint members when torque is being transmitted.

Referring now to Figure 2 of the drawings, there is shown a practical embodiment of how an axially resilient torque transmitting connection can be provided between the shaft part and outer joint member In this joint, parts corresponding to those in Figure 1 are indicated by the same reference numerals, whilst the outer joint member additionally has an axial cylindrical extension 13. This is connected to the shaft part 10 by an axially resilient annular diaphragm 14 of sheet metal, welded at its external periphery to the joint extension 13 and at its inner periphery to the shaft part 10, so that the diaphragm 14 can transmit torque between the outer joint member and shaft part Referring now to Figure 3, this shows a further embodiment of joint wherein, again, the same reference numerals are used for corresponding parts As for the embodiment of Figure 2, a diaphragm 14 connects shaft part 10 to a cylindrical extension 13 on the outer joint member 6. However, the shaft part 10 also has a radially extending flange 16 and an axially extending sleeve 15 which closely surrounds the extension 13 on the joint outer member The joint outer member carries a sheet metal shroud 17 (retained by swaging into a groove 18 on the exterior of the joint outer member) which itself extends axially to cover and protect the sleeve 15 attached to the shaft part 10 The sleeve 15 and extension 13 on the joint outer member together act as stop elements to ensure that close alignment is maintained between the shaft part and joint outer member, without the diaphragm 14 being subject to excessive bending.

The shroud 17 provides some protection for, and prevents penetration of dirt to, the sleeve 15 and diaphragm 14.

Figure 4 shows an axial view of an embodiment of diaphragm 14 It is of annular form, with a central aperture 19 for receiving a spigot at the end of the shaft part 10 to which it is welded It has apertures in the~ form of circumferentially extending slots 2Q arranged on different radii, for increased axial flexibility without requiring a very large overall diameter.

As possible alternative configurations, the diaphragm could be provided with radially extending slots, egZ as shown in outline at 20a Such slots may extend to the outer periphery so that the diaphragm takes on the shape of a star A further alternative is that metal strips crossed in the manner of wheel spokes could be provided (as indicated at 20b), and in this case half the total number of such strips would be under tension when torque is being transmitted. Such strips may extend between inner and outer annular parts for connection to the shaft part and joint member.

Figure 5 shows a universal joint which is very similar to that of Figure 3, and again the same reference numerals are used. In this case, two resilient annular members 21 have been provided, e.g. of rubber or plastics material. The first member 21 is disposed between the diaphragm 14 adjacent the outermost periphery thereof and the flange 16. The other member 21 is provided on the other side of flange 16, between it and a radially inwardly extending lip at the adjacent end of shroud 17.

These form stops to limit relative axial movement between the shaft part and outer joint member. In addition to preventing excessive deformation of the diaphragm, they absorb any impact at the limits of relative axial movement and prevent noise from being generated.

Referring now to Figure 6 of the drawings, this shows a universal joint in which a substantially different form of axially flexible means is provided to connect the shaft part 10 to the outer joint member 6.

In this embodiment, a sheet metal protective cap 23 is shown at the end of the joint The shaft part 10 terminates in an outwardly extending bell 9, and an axially resilient sleeve 22 is connected, by welding, between the outer joint member 6 and the outer periphery of the bell 9. The sleeve member 22 is of sheet metal, provided with diamond shaped apertures 24 to give it the necessary axial resilience. It has to be stiff enough to ensure that misalignment of the outer joint member 6 relative to the shaft part 10 is avoided, and does not lead to any damage to the sleeve member which has to transmit the entire torque between the shaft part and outer joint member.

Figure 7 shows a universal joint basically corresponding to that of Figure 6, with the additional feature that the outer joint member is provided with a rigid cylindrical supporting sleeve 36 which extends axially to closely surround the flexible sleeve 22. The sleeve 26 is fixed on the outer joint member by engaging a groove 25 on the outer surface thereof This prevents undesired relative articulation or misalignment between the outer joint member and shaft part In a possible modification of this type of joint, shown in Figure 8, the outer joint member has a cylindrical extension 13 forming an internal supporting sleeve which lies within the torque transmitting sleeve 22.Fitting closely within the sleeve 22, the extension 13 is effective to prevent relative articulation or misalignment between the outer joint member and shaft part It also is arranged to abut the bell 9, to limit axial compression of the sleeve 22.

Figure 9 shows four different embodiments of how the sleeve 22 may be configured to increase its axial flexibility. Figure 9a shows the sleeve with rectangular apertures 24a so that the remaining material of the sleeve comprises, in effect, helically extending intersecting webs at a helix angle of forty-five degrees Figure 9b shows the sleeve with diamond shaped apertures 24b, as shown in Figure 6 Figure 9c shows the sleeve with circumferentially extending slots 24c, adjacent rows of slots being circumferentially staggered relative to one another Such slots (24d, Figure 9d) may be filled with flexible inserts 26 of a rubber or plastics material Referring now to Figure 10 of the drawings, this shows a constant velocity ratio universal joint which in principle is similar to that of Figures 6 to 8, in that torque transmission between the shaft part 10 and outer joint member 6 is by way of a perforated axially resilient sleeve 22. The sleeve 22 closely surrounds a substantial part of the outer joint member 6 and a relatively short axial extension 13 therefrom. In this joint, however, the shaft part 10 is provided with an axial bore 28 receiving, as a sliding fit, a shank 30 provided at the radially innermost part of an internal bell member 29. The outermost part of bell member 29 has a form fitting connection within the axial extension 13 of the outer joint member, being retained therein by a retaining ring 31, such form fitting connection being effective against relative axial and angular (articulation) movements, whereas slight rotational movement and radial movement is permitted.The shank 30 is axially slidable in the bore 28 to a limited extent, the limits of such movement being determined by a pin 32 passing through the shaft part 10 and through an axially elongated bore 33 in the shank 30. To reduce frictional resistance to axial displacement of the shank 30 in the bore 28, two sliding bushes 34, 35 are provided.

This arrangement ensures that there is low resistance to axial displacement between the shaft part and outer joint member. At the same time, angular movement between these parts is prevented by the arrangement of inner bell 29 and its shank 30. Also excessive torsional displacement between the shaft part and outer joint member is limited. Axial displacement between the outer joint member 6 and shaft part 10 is limited in one sense by abutment of extension 13 with bell 9, and in the other sense by contact of the pin 32 with the boundary of the axially elongated aperture 33.

At the opposite end of the universal joint, sheet metal cap 23 fitted on the outer joint member provides an attachment for a flexible sealing boot 27 whose other end, not shown, would be connected to the shaft 5.

Referring now to Figure 11 of the drawings, this shows a universal joint 103 with an inner joint member 104, outer joint member 110, torque transmitting balls 111, and ball cage 112. The inner joint member 104 has a splined bore 105 receiving a splined end of a shaft 101, retained by a spring ring 106. A sheet metal sleeve 113 fitted on the outer joint member receives one end of a flexible sealing boot 114, whose other end is fixed to the shaft 101.

The end of the outer joint member opposite that at which the sleeve 113 is fitted is provided with a rigid hollow cylindrical axial extension 109. This is connected to a shaft part 102 by two axially spaced diaphragms 107a, 108a. The diaphragms are annuli of sheet metal, the diaphragm 107a being integral with a collar 115 fitted on the end of the shaft part 102. This diaphragm 107a is welded to the extremity of the extension 109 of the outer joint member. The diaphragm 108a is welded at its outermost periphery to the extension 109, and at its inner periphery to the end of a spigot 116 at the end of the shaft part 102.

The diaphragms 107a, 108a, have approximately the same wall thickness as each other, and partake approximately equally in torque transmission between the shaft part 102 and the outer joint member. At the same time they are relatively resilient to permit small axial displacements between the shaft part 102 and the outer joint member 110, whilst holding these parts in alignment with one another. One or both diaphragms may be slotted as above described with reference to Figure 4, to increase its axial resilience. The diaphragms also serve to seal the universal joint at its side opposite the boot 114.

Referring now to Figure 12, this shows, as for Figure 11, a constant velocity ratio universal joint of plunging type, with an inner joint member 104, an outer joint member 110, torque transmitting balls 111, and an annular cage 112. The inner joint member has a splined bore 105 receiving a splined end portion of a shaft 101, retained by a retaining clip 106. Sheet metal sleeve 113, to which boot 114 is attached, is held to the outer joint member by circumferentially spaced axially extending bolts 119 At the opposite end of the outer joint member to the sleeve 113, the bolts 119 also secure an annular part 117 to the joint member. This has an axial extension 109, whose free end interfits with the outer periphery of a diaphragm 108b.Such interfitting, which provides for torque transmission between the outer joint member and diaphragm, may be by way of radially extending fingers at the outer periphery of the diaphragm, engaging in recesses in the extension 109, the latter being, for example, generally of castellated form.

At its inner periphery, the diaphragm 108b has an axially extending sleeve 120 which is internally splined at 121, fitting on an externally splined end portion of a spigot 116. The spigot 116 has a collar 115, and is either fitted on or integral with a shaft part 102.

The annular part 117 also has fitted thereto a sheet metal sleeve 118 extending axially in the direction of the shaft part 102, terminating in an inwardly extending diaphragm portion 107b whose radially innermost periphery is received between the collar 115 and the end of the internally splined sleeve 120. Thus the arrangement is that the diaphragm 108b provides for all torque transmission between the shaft part 102 and the outer joint member 110 by way of the annular part 117. The diaphragm 107b maintains alignment between the outer joint member and shaft part 102. The diaphragms are resilient to permit relative axial displacement between the shaft part and outer joint member, and a rigid or resilient member 122 may be disposed between the two diaphragms, to limit such displacement.

Although in the above embodiments the universal joints are plunging joints able to accommodate relative axial movement between the inner and outer joint members, the invention is also applicable to axially fixed joints.

Claims

1. A constant velocity ratio universal joint, comprising two joint members connected to one another for torque transmission and relative articulation therebetween, wherein one of said joint members is connected to a shaft part by resilient means permitting relative axial movement between the joint member and shaft part and providing a torque transmitting connection therebetween.

2. A universal joint according to Claim 1 wherein said resilient means comprises a resilient diaphragm extending generally radially between said shaft part and joint member.

3. A universal joint according to Claim 2 wherein the shaft part and joint member have stop elements cooper able to limit relative movement in at least one sense therebetween

4. A universal joint according to Claim 2 or Claim 3 wherein the diaphragm is provided with apertures in the form of slots extending generally circumferentially therein.

5. A universal joint according to Claim 2 or Claim 3 wherein the diaphragm is provided with apertures in the form of slots extending generally radially therein.

6. A universal joint according to Claim 3 or Claim 4 or 5 as appendant there-to wherein at least one resilient element is provided in association with the stop elements and diaphragm.

7. A universal joint according to any one of Claims 2 to 6 wherein said shaft part and joint member are connected by two axially spaced generally radially extending resilient diaphragms.

8. A universal joint according to Claim 7 wherein said two diaphragms have radially outer portions connected to a rigid axial extension of the outer joint member.

9. A universal joint according to Claim 7 or Claim 8 wherein the two diaphragms have radially inner portions connected to a rigid shaft part.

10. A universal joint according to any one of Claims 7 to 9 wherein one of said diaphragms is connected for torque transmission between the shaft part and joint member, and the other is connected therebetween to provide radial and axial support only.

11. A universal joint according to any one of Claims 7 to 9 wherein both of said diaphragms are connected for torque transmission between the shaft part and joint member.

12. A universal joint according to any one of Claims 7 to 11 wherein at least one of said diaphragms is provided with slots to increase its axial flexibility.

13. A universal joint according to any one of Claims 7 to 12 wherein a rigid stop element is disposed between the diaphragms, spaced by a small axial distance therefrom.

14. A universal joint according to any one of Claims 7 to 12 wherein a flexible element is disposed between the diaphragms.

15. A universal joint according to any one of Claims 2 to 14 wherein the diaphragm or at least one of the two diaphragms comprises strips of material extending in the manner of spokes of a wheel.

16. A universal joint according to Claim 1 wherein the resilient means comprises an axially resilient sleeve connected at its one end to the shaft part and at its other end to the joint member.

17. A universal joint according to Claim 16 further comprising a supporting sleeve closely surrounding the axially resilient sleeve and rigidly connected to one of the shaft part and the outer joint member.

18. A universal joint according to Claim 16 further comprising a supporting sleeve disposed within the axially resilient sleeve and rigidly connected to one of the universal joint member and shaft part.

19. A universal joint according to any one of Claims 16 to 18 wherein the resilient sleeve comprises apertures and helically extending intersecting webs of material therebetween.

20. A universal joint according to any one of Claims 16 to 18 wherein the resilient sleeve comprises apertures in the form of a number of rows of circumferentially extending slots, circumferentially staggered relative to one another.

21. A universal joint according to Claim 19 or Claim 20 comprising elements of flexible material in said apertures.

22. A universal joint according to any one of the preceding claims wherein said one joint member comprises an outer joint member, and there is provided supporting means connected on the one hand to said outer joint member and on the other hand to the shaft part, to prevent relative angular movement therebetween.

23. A universal joint according to any one of the preceding claims wherein said one joint member comprises an outer joint member, and there is provided stop means connected on the one hand to said outer joint member and on the other hand to the shaft part, to limit relative axial movement therebetween.

24. A universal joint according to Claim 23 as appendant to Claim 22, wherein said supporting means and stop means comprise a bell member connected to the outer joint member by a connection preventing angular movement and axial m-ovement therebetween, and having a shank portion received in a bore in the shaft part for limited axial movement- therein.

25. A universal joint according to Claim 24 wherein the connection between said bell member and joint outer member permits some relative radial movement therebetween

26. A universal joint according to any one of the preceding claims wherein the joint members are able to accommodate relative axial movement therebetween.

27 A universal joint substantially as hereinbefore described with reference to any one of Figures 2 - 11 of the accompanying drawings.