Abstract: A power steering system includes a housing and a first member supported by the housing for movement relative to the housing. A second member is supported by the housing for movement relative to the housing and the first member. Steerable vehicle wheels are moved in response to relative movement between the first and second members. A power steering resistance control system resists relative movement between the first and second members with a force which varies as a function of variations in vehicle speed. Material is located in a chamber circumscribing the first member. The material has a viscosity which varies as a function of the magnitude of an energy field acting thereon to vary the resistance to relative movement between the first and second members. The energy field is applied to act on the material with a magnitude that varies as a function of the vehicle speed.

Abstract: An improved power steering motor seal performs three functions. The seal engages a tubular motor cylinder wall to prevent leakage of fluid between the wall and a housing. The seal also engages a rack bar to prevent fluid leakage between the rack bar and the housing. In addition, the seal blocks exposure of the housing, which is fluid pervious, to the fluid pressure in a motor chamber. The seal includes an annular body section which is disposed in a cavity in one end of the housing and engages the rack bar. The seal has a flange section which extends across the outer end of the housing into sealing engagement with the motor cylinder wall. A metal reinforcing member is provided to hold elastomeric sealing material in the flange section in sealing engagement with the inner surface of the motor cylinder wall.