Patent ID: 6681885
Filing Date: 2004-01-27
Classification: B62D

Abstract:
A rack and pinion steering apparatus for turning steerable wheels of a vehicle in response to rotation of a steering wheel, the apparatus comprising:a housing; a rack bar extending through the housing and movable relative to the housing for turning the steerable wheels of the vehicle, the rack bar having a plurality of teeth; a pinion gear located within the housing and being rotatable relative to the housing, the pinion gear including a plurality of helical teeth that meshingly engage teeth of the rack bar, engagement of the helical teeth of the pinion gear with the teeth of the rack bar during rotation of the pinion gear in a first direction resulting in an axial force acting on the pinion gear; a shaft connectable with the steering wheel of the vehicle and being rotatable relative to the housing, at least a portion of the shaft extending into the housing and connecting with the pinion gear, rotation of the shaft effecting rotation of the pinion gear; and an assembly interposed between the shaft and the housing, the assembly comprising a first snap ring that is attached to the portion of the shaft extending into the housing and a second snap ring that is attached to the housing, interposed between the first and second snap rings are only a fluid tight seal for blocking fluid leakage from the housing and a bushing for enabling rotation of the shaft relative to the housing, the bushing including a radially extending surface for engaging the first snap ring to block axial displacement of the pinion gear due to the axial force acting on the pinion gear, wherein the bushing is formed from powered metal, and a percentage of iron in the powdered metal ranges from 91.1% to 95.4%, a percentage of copper in the powdered metal ranges from 4.0% to 0.9%, and a percentage of carbon in the powdered metal ranges from 0.6% to 0.9%.