Pre-cap ball joint
Page 61
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A reduction in wheel shimmy and an elimination of knocking or hammering of the bearing surface are among the advantages claimed by the Hitchin-based Cam Gears Group for a ball joint introduced for vehicle steering and suspension systems.
In this design the ball-pin is encapsulated in a pre-formed high-density polyethylene socket. During assembly the end plug is pressed against the socket with a determined pre-load which is maintained while the roll-closing operation is carried out.
With this design, the preloaded material expands as the socket wears with use. thus eliminating any tendency for endplay to develop. This characteristic removes the need for a separate spring and spring seat and this, coupled with the low cost of the polyethylene material, results in a reasonably priced component.
Considerable operating advantages are also claimed for the new concept, particularly over all-metal, greased and conventional spring-loaded two-piece socket types. These include greater road shock isolation properties and more constant ball-pin torque under varying load conditions.
Another point stressed by the developers is that the smaller axial socket deflection under load gives a decidedly firmer feel to the steering or suspension system.
Introduction of these pre-cap joints on current vehicles presents no special problems as interchangeability with the current range of joints is being preserved.
Development work has to date been concentrated on steering and suspension units for passenger vehicles and for light, medium and heavy trucks. Other applications are envisaged. These take in special truck axle balljoints and radius rods, wishbone pivot joints and tractor steering joints.
Made by: Cam Gears Group. Hitchin, Hertfordshire.