Patent GB-1147177-A (GB)
Title: Wear compensating movable joint device
IPC: F16C11/06
Filed: 1966-11-18
Abstract: 1,147,177. Ball and socket joints; wear compensating device. MOOG INDUSTRIES Inc. 18 Nov., 1966 [6 Dec., 1965], No. 51853/66. Heading E2F. A ball and socket joint for motor vehicles, of the type having a load supporting stud with an enlarged head journaled in a housing, has a wear compensating device responding to frictional forces produced by relative rotation of the stud and housing by effecting linear displacement of the bearing parts towards each other. A housing 10 has an opening 11 at one end, internally formed to provide a seat 12 for a bearing 13. A stud 14 has an enlarged part spherical, head 15 mounted on the bearing, with a shank 16 projecting, through a bore in the bearing, from the opening 11. The opposite end of the housing is closed by a cover plate 17 retained by a spun over flange 18. Between the stud head and cover is a wear compensating unit comprising a bearing element 19, a fixed ring element 20, a fixed ratchet ring 21 and ratchet fingers 22, the bearing element having a part spherical bearing surface 23 of a greater radius than that of the stud head, giving a clearance space 24 outwardly of the zone of contact surrounding the lubricant passage 25; the element also has an externally threaded surface 26, and a plurality of radial slots 27 into which are press fitted the ratchet fingers. The ratchet ring is press fitted into a counter bored part of the housing at 29 so that its internal teeth 30 surround and engage the ratchet fingers, and above it in the same counter bore is pressed the ring element, which has internal threads 31 which operably engage the external threads 26 on the bearing element. The stud head has an annular recess 33 which carries a resilient "O" ring 34 extending beyond the surface of the stud head until compressed by the axial load applied during assembly by spinning down the flange onto the cover plate. When wear of the parts produces axial clearance, the resilient ring extends beyond the head surface, and the resulting increased frictional moment on the part spherical surface 23 of the bearing element 24 causes this element to rotate in the threads 31, whereby it moves axially towards the stud head until such time as the clearance is taken up and the "O" ring again compressed. Reverse rotation and axial movement is prevented by the ratchet fingers engaging the teeth of the ratchet ring. An alternative embodiment described is one wherein the "O" ring is mounted in an annular circumferential flange on a shallow cup shaped element fitting closely over the stud head. The invention also includes a ball joint having a similar wear compensating device, but wherein the frictional force is supplied either by a magnetic part spherical segment which replaces a cutaway portion of the top of the stud head, or by an annular magnetic ring carried in a flange or cup shaped element similar to that mentioned above as carrying the "O" ring. A further ball joint is one for compression loading, in which an "O" ring or a magnet is disposed around the base of a ball headed stud bearing on the upper face of a housing, the wear compensating device being similar in principal but the bearing member being annular in shape, surrounding the ball stem, and having a single 360‹ lower cam surface riding on a similar upper surface on a ring element fixed in the base of the housing. Also disclosed is a joint suitable for an idler arm, which incorporates the inventive compensating device but is only rotatable in the housing rather than being both angularly and rotatably mounted. The various bearing parts may be made of steel, suitably surface hardened, sintered metals (e.g. iron), phenolic resins or synthetic elastomers such as nylon, the ball head preferably being of metal and the bearing element of plastics material, or vice versa.