Patent GB-645900-A (GB)
Title: Improved vehicle suspension
IPC: B60K17/22
Filed: 1948-03-19
Abstract: 645,900. Vehicle suspensions. GENERAL MOTORS CORPORATION. March 19,1948, No. 8181. Convention date, March 21, 1947. [Classes 108(ii) 'and 108(iii)] In a vehicle suspension, each wheel of a pair is mounted by a forwardly directed link, a transverse tie rod and a vertically disposed telescopic spring strut. The transverse tie rods may cross one another at the centre line of the vehicle, and in the case of the steerable wheels the axis of the telescopic spring strut may form the steering axis of its associated wheel. Fig. 2 shows rear driving wheels each mounted on a forwardly directed link 97, tie rod 95 and vertical telescopic strut 83; the lower end of the strut 83 is pivoted to the wheel carrier, the pivot being longitudinally disposed. The tubular casings 9, 10 and differential 6 are rigidly mounted and the ends of the links 97 and tie rods 95 are mounted by rubber bushes. The link 97 may be adjusted in length by rotating the centre portion which is screwed over end portions of left- and right-hand thread. The tie rods 95 are cranked where they cross one another. Figs. 2 and 9 show the front steering wheel. mountings, each of which comprise a transverse tie rod 16 whose inner end is secured to a frame member 2 by a rubber bush and whose outer end is secured to the wheel carrier 13 by a ball and socket joint 21 to permit of steering movements, and a forwardly directed link 15 whose rear end is attached to the outer end of the tie-rod 16 and whose forward end is secured by a rubber bush to the frame. Each telescopic spring strut includes a hydraulic shock-asborber and is fastened at its lower end to a bracket 24 fast with the wheel carrier and at its upper end to the vehicle body through a rubber bush 76. The spring strut is designed to permit relative rotation of its ends so that the wheel can be steered about the axis of the strut; the ball joint 21 is arranged approximately in line with such axis. Each link 15 comprises a rotatable centre portion threaded on to ends of left- and righthand thread whereby the length of the link may be varied to adjust the caster of its associated wheel. The spring strut and shock absorber, Fig. 3, comprises an outer tube 25 secured to the wheel carrier and which carries a collar 67 and flange 65 on which is seated the spring 64, and a relatively slidable inner tube 28 to the upper end of which is secured a flange 63 which carries a seating 62 for the upper end of spring 64, the inner tube assembly being rotatably mounted on a stud 58 by needle bearings 57 and a ball bearing 73, the stud 58 being secured to a body member by a rubber bush 76 and nut 80. In the case of the rear wheels where rotational movement of parts of the strut is not required, the needle and ball bearings are omitted. The inner tube 28 is guided in the top of the outer tube by a bearing 29, and is guided at its lower end firstly by a bearing cap 27 secured to the end of the inner tube and slidably engaging a stationary intermediate tube 26 and secondly by a piston 37 fixed to the stationary hollow piston rod 36. The space 50 beneath the piston and the space 43 beneath the bearing cap 27 are filled with oil, and the space 47 between the intermediate tube 26 and outer tube 25 acts as an oil reservoir. The piston rod is surmounted by a spring-loaded flap valve 38; the bearing cap has one set of oil ways 49 therethrough closed at the top by flap valves and another set 53 closed at the bottom; the reservoir 47 communicates with the chamber 43 through ports 46 closed by the spring-pressed valve ring 48. In operation, when the inner tube descends, the space 50 beneath the piston is enlarged and the chamber 43 is made smaller. Oil passes through the oil ways 49 into the space 50, and the excess oil (due to the diameter of the chamber 43 being greater than that of the space 50) passes through the holes 42 up the hollow piston rod and through the one-way valve 38 into the inner cylinder. When the inner tube rises, contraction of the space 50 and enlargement of the chamber 43 firstly causes oil to pass through the oil ways 53 and secondly oil passes from the reservoir 47 through one-way valve 48 and port 44 into the chamber 43. Thus continued reciprocation results in oil being withdrawn from reservoir 47 and passed to the inner tube 28 above the piston. As a result, the oil level in inner tube 28 gradually rises until it reaches the holes 55 whereby the bearing 29 is lubricated, a small amount being retained in the annular groove 56 for this purpose, and the rest of the oil either passes down between the inner and outer tubes through the perforations 32 back to the reservoir 47, or down the outside of the outer tube until it is trapped by the bottom of the bellows 59 and returns through holes 60 back to the reservoir. To preserve atmospheric pressure within the bellows 59, the enclosed space is in communication at the top through the hollow stud 58, flexible pipe 82 and an air filter (not shown) with the atmosphere. In the modified form referred to above wherein relative rotary movement of the inner and outer tubes 28, 25 for steering purposes is not required, the air filter may be mounted directly on the top of the stud 58.