GB1585164A

GB1585164A - Universal joint and shaft assemblies

Info

Publication number: GB1585164A
Application number: GB41458/79A
Authority: GB
Original assignee: GKN Transmissions Ltd
Current assignee: GKN Automotive Ltd
Priority date: 1976-06-24
Filing date: 1977-06-22
Publication date: 1981-02-25

Description

(54) IMPROVEMENTS RELATING TO UNIVERSAL JOINT AND SHAFT ASSEMBLIES (71) We, GKN TRANSMISSIONS LIMITED, a British Company of P.O. Box 405, 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 universal joint and shaft assemblies and methods of making same. The invention has been developed primarily for application to assemblies of this kind for use in motor road or other automotive vehicles for transmitting the drive from the prime mover to driving wheels either at the rear or at the front of the vehicle.

It is desirable to avoid or minimise vibration due to an out-of-balance mass in such an assembly, a condition which exists when the combined centre of mass of the universal joint and the shaft member is offset radially from, i.e. is eccentric with respect to, the axis about which the shaft member and the member of the universal joint to which the shaft is secured rotate.

Such eccentricity may be brought about by the following causes. Firstly, the axis about which the assembly of shaft member and the member of the universal joint connected thereto actually rotates is determined by the axis of rotation of the other member of the universal joint, and eccentricity may be produced by the dimensional tolerances in the universal joint itself and the accuracy of fit of the universal joint members with respect to each other, i.e.

the presence or absence of any radial play or lost motion. Secondly, eccentricity may be produced by reason of a lack of accuracy in the manner in which the shaft member is connected to that part of the universal joint member to which it is connected and which usually is in the form of a stub shaft or spigot (of which the geometrical axis should ideally be coaxial with the actual axis of rotation of the universal joint).

Thirdly, eccentricity may be produced by reason of the actual centre of mass of the shaft member not lying on the geometrical axis of the shaft member, i.e. being offset radially therefrom.

In many cases the universal joint and shaft assembly is required to transmit drive to the input element of a combined reduction and differential gear, the output elements of which are connected respectively to drive shafts which in turn are connected to the driving wheels of the vehicle, usually but not invariably at the rear thereof.

In such cases the shaft member which forms part of said assembly is normally termed the propeller shaft and rotates at an appreciably higher speed than does either of the drive shaft, typically three or four times as high. Consequently the elimination of eccentricity giving rise to vi bration is especially important.

Whilst continuous research and development has been directed to the elimination of the first cause of eccentricity referred to above, it is still necessary to accept that because of production tolerances a significant number of assemblies will present some eccentricity arising from the first cause but within said production tolerances.

Furthermore, although normal methods of joining the shaft member to the universal joint member to which it is required to be connected, and in particular welding methods, have been carefully designed to avoid or minimise the second cause of eccentricity, here again it has to be accepted that in mass production some of the assemblies produced will exhibit eccentricity through this second cause.

With regard to the third cause of eccentricity, minimisation of this is often somewhat beyond the control of a manufacturer of assemblies of the kind specified in that reliance has to be placed upon the adher ence to accurate tolerances by the suppliers of tubular stock from which such shaft members are made. Accuracy in this res pect is closely related to price and for the price which is acceptable, having regard to the product to be produced and its intended use, for example in mass produced motor vehicles, it is clearly necessary to tolerate some eccentricity from this third cause.

The present invention is based upon the concept that vibration arising from all three causes of eccentricity is capable of being reduced if the overall mass of the assembly, and in particular the shaft member, can be reduced.

Conventional practice is to make the shaft member and the universal joint member to which it is to be connected of a ferrous metal, such as steel or cast iron, and to join these members to each other by welding.

The use of welding technique for this purpose does represent a design constraint by reason of the fact that the metals employed for two members must then necessarily be selected to have welding compatibility. Further, the use of a ferrous metal for the manufacture of the universal joint member (or indeed the universal joint as a whole) is consequent upon the necessity in a large number of applications, such as propeller shaft in universal joint assemblies for motor vehicles, to comply with strength requirements which have to be met.

The present invention is based on the concept of reducing the overall mass of the assembly and involves the provision of a mode of securement of the shaft member to the universal joint member which overcomes the compatibility constraint.

In accordance with one aspect of the present invention there is provided a method of making an assembly of a universal joint member and a shaft formed of fibre reinforced synthetic resin material, said method including: providing a connecting member of a material capable of being welded to the universal joint member and establishing an adhesive connection between the shaft and connecting member by incorporating the connecting member in the shaft during manufacture thereof so that the synthetic resin material of the shaft adheres to the connecting member; and subsequently welding the connecting member to the universal joint member.

In accordance with a further aspect of the present invention there is provided an assembly of a universal joint member and a shaft formed of a fibre reinforced synthetic resin material, said assembly including a connecting member incorporated in the shaft and adhesively secured thereto by the synthetic resin material impregnating the fibres, the connecting member being welded to the universal joint member.

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 in vertical diametral section of a portion of a shaft and universal joint assembly showing the connection of the shaft member to one of the members of the universal joint and the final stage of making same; FIGURE 2 illustrates the first stage in making the assembly of Figure 1; FIGURE 3 is a fragmentary view showing respective axially interfitting parts of a shaft member and a universal joint member in diametral cross-section in accordance with a further embodiment of the invention; FIGURE 4 illustrates the third stage of performing the method of making the assembly of Figure 3; FIGURE 5 illustrates the first stage in making the assembly of Figure 3; and FIGURE 6 illustrates the second stage of making the assembly of Figure 3.

Referring firstly to Figure 1, the assembly includes a universal joint 310 and a shaft member 311. For convenience only one end portion of the shaft member is shown.

A like universal joint member may be provided at the opposite end or, according to requirements, this other end may have other means for connecting it in the drive or transmission line. The universal joint shown is of the Hookes type including yoke members 312 and 313 including respective laterally spaced axially projecting yoke arms 314, 315 connected by base parts 316, 317 and coupled together by a connecting member 318 having two pairs of radially projecting spigots engaged in openings in the yoke arms through the intermediary of bearings 319, 320 respectively, the positions of which along respective axes 319a and 321 are determined by circlips, as shown for example at 323.

All of the members of the universal joint may be formed of a ferrous metal by casting, forging or fabricating methods in order to provide the necessary strength for applications such as propeller shaft and universal joint assemblies for motor vehicles.

The shaft member 311 is formed from a synthetic resin reinforced with an inorganic fibrous material, for example glass fibres and/or carbon fibres.

A part 312a is initially structurally separate from the remainder of the joint member 312 and secured to the shaft member 311 by bonding at contiguous circumferential surfaces of it and shaft part 311a.

Thereafter a portion of the part 312a which projects from the extremity of the part 311 a is united with part 312j, namely a tubular spigot which is formed integrally with the member 312. As illustrated, the junction may be a welded junction and 335 is a welded structure and may be formed by friction welding. Work holding heads of the chuck type, one of which is driven relatively to the other, may be provided on a friction welding machine for holding the shaft member 311 and universal joint portion 312j to carry out the welding operation. Conventional welding, e.g. arc welding, could be employed if the materials are compatible.

The bonding of the contiguous surfaces of the parts 311a, 312a may be effected during formation of the shaft member and one manner of carrying this out is illustrated in Figure 2.

A plurality of metal sleeves, forming two parts 312a, being the same metal as the remainder of the member 312, are placed on a mandrel 332, the integral diameter of each such sleeve being such that it may be assembld as a close sliding fit onto the mandrel.

A covering 335a from which the shaft members are formed is produced by winding on a web 336 of reinforcing fibres, for example glass or carbon fibre. A plurality of.layers of winding in opposite directions or hands can be carried out and thereafter, when sufficient thickness has been built up to form the shaft member, longitudinal fibres may be laid over the helically wound fibres and the whole impregnated with a suitable resin such as a thermosetting epoxy resin, applied, for example, by brush 336, and which is thereafter subjected to heating to cure it.

The heat treatment may be effected by a batch process, i.e. placing a quantity of the universal joint and shaft assemblies in a chamber in which the atmospheric temperature is in the range appropriate to the adhesive and materials employed, or by passing the assemblies in succesion through the chamber in which the atmosphere is raised to appropriate temperature.

The sleeves may be each of a length equal to, or, slightly more than, twice the length of the part 312a, to be incorporated in any given shaft member, and the product illustrated in Figure 2 may be cut, for example by a saw or other dividing tool 337, in a plane midway between the ends of each sleeve. A portion of the nonmetallic shaft material is thereafter cut away adjacent to the free end (as illustrated in Figure 4 for the embodiment of Figure 3) so as to leave a portion of each part 3 12a projecting as shown in Figure 1.

The curing treatment (heating) causes the resin to become bonded to the exterior surface of each part 312a. In many cases it may be sufficient for such bonding to be established merely by close penetration of the resin into surface irregularities of the metal sleeve forming the part 312a. If desired, however, the exterior surface of the sleeve may be knurled or otherwise deformed to provide depressions or projections producing substantially positive keying between the non-metallic material of the shaft member and the part 312a.

Alternatively, the composition of the resin may be selected in relation to the metal used for the sleeves to establish a bond by molecular linking between the contiguous surface layers.

In the modified embodiment illustrated in Figure 3 wherein corresponding parts are designated by like references with the prefix 4 and to which the preceding description is to be deemed to apply, the sleeve from which the part 412a of the universal joint member is formed has an integral diameter somewhat larger than the diameter of the mandrel 432 and is applied over the latter, as seen in Figure 6, only after a first layer 434a of fibres has been wound onto the mandrel as seen in Figure 5. Such winding is continued after assembly of the sleeve to form a second layer 434b, thereby producing spaced parallel walls 411j, 411k on the shaft member between which the part 412a is received.

Curing by heating is effected after the sleeve forming the part 412a is in position and so bonding takes place between both inner and outer circumferential surfaces of the part 412a and the shaft member.

Again, some deformation may be effected such as knurling these interior and exterior surfaces of the sleeve prior to assembly onto the partly formed shaft member on the mandrel.

Division may be effected at a position midway between the ends of the sleeve by a dividing tool 437 and thereafter, as seen in Figure 4, part of the first and second layers 434a, 434b are cut away by tools 438, 439 of any suitable form.

The exposed portion of sleeve 412a securely embedded in shaft member 411a is then welded to the remaining part 412j.

Although in the foregoing description reference has been made to the formation of the universal joint members from a ferrous metal, e.g. cast iron or steel, it is to be understood that where the torque to be transmitted admits the universal joint member could itself be formed of a light weight (low density) material. This could be an aluminium alloy. The universal joint member may be formed as a casting, and the joint between the shaft member and the universal joint member could be effected as shown in any one of the preceding embodiments.

Further, the invention is of application to an assembly of a shaft with some other form of universal joint member e.g. one from a constant velocity universal joint having inner and outer members and torque transmitting rotary elements such as balls engaging in formations such as grooves in the inner and outer members.

WHAT WE CLAIM IS:- 1. A method of making an assembly of a universal joint member and a shaft formed of fibre reinforced synthetic resin material, said method including: providing a connecting member of a material capable of being welded to the universal joint member and establishing an adhesive connection between the shaft and connecting member by incorporating the connecting member in the shaft during manufacture thereof so that the synthetic resin material of the shaft adheres to the connecting member; and subsequently welding the connecting member to the universal joint member.

2. The method according to Claim 1, further including the steps of: (a) placing the connecting member on a mandrel; (b) applying reinforcing fibres to the connecting member and the mandrel to form the shaft with the connecting member set in an end thereof; (c) impregnating the reinforcing fibres with hardenable synthetic resin; (d) hardening the synthetic resin in form a solid matrix in which the fibres and the connecting member are embedded; and (e) removing the mandrel from the shaft and connecting member.

3. The method according to Claim 2; further including: (a) initially placing a plurality of connecting members on the mandrel at spaced intervals therealong; (b) subsequent to removal of the mandrel, severing the resulting assembly at positions coinciding with the connecting members to form discreet tubes of fibre reinforced synthetic resin material with connecting members incorporated in each end thereof; and (c) removing the fibre reinforced synthetic resin material immediately adjacent the ends of each tube to expose the connecting members to permit welding thereof to universal joint members.

4. The method according to Claim 3 further including applying reinforcing fibres to the mandrel prior to placing the connecting member thereon.

5. An assembly of a universal joint member and a shaft formed of a fibre reinforced synthetic resin material, said assembly including a connecting member incorporated in the shaft and adhesively secured thereto by the synthetic resin material impregnating the fibres, the connecting member being welded to the universal joint member.

6. The assembly according to Claim 5, wherein the connecting member is incorporated between inner and outer layers of said fibre reinforced synthetic resin mat- erial.

7. A method of making an assembly of a universal joint member and a shaft, substantially as described herein with reference to the accompanying drawings.

8. An assembly of a universal joint member and a shaft, substantially as described herein with reference to the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. torque transmitting rotary elements such as balls engaging in formations such as grooves in the inner and outer members. WHAT WE CLAIM IS:-

1. A method of making an assembly of a universal joint member and a shaft formed of fibre reinforced synthetic resin material, said method including: providing a connecting member of a material capable of being welded to the universal joint member and establishing an adhesive connection between the shaft and connecting member by incorporating the connecting member in the shaft during manufacture thereof so that the synthetic resin material of the shaft adheres to the connecting member; and subsequently welding the connecting member to the universal joint member.