Abstract: Rack and pinion steering gear with hydraulic power assist that is reduced as the vehicle wheels approach their positive wheel stops so that hydraulic loads on the steering gear and linkage are reduced and the power steering pump is not forced to excessive operation in relief.

Abstract: A hydraulic power steering system has a vane type pump which is operable to supply fluid to a steering gear at a volumetric rate determined in part by the system pressure or system demand. The pump flow is partially bypassed through a valve member disposed in the cam ring at a position adjacent the pumping chambers. The valve is spring loaded radially inward to permit the bypass flow at low system pressure levels. Increasing system pressure levels bias the valve member radially outward thereby reducing bypass flow while simultaneously increasing pump discharge flow. At a predetermined pressure level, the valve member will reach a secondary opening position to bypass fluid flow and thereby limit the maximum system pressure.

Abstract: A hydraulic power steering system has a vane type pump which is operable to supply fluid to a power steering gear at a volumetric rate determined in part by the system pressure or system demand. The flow from the pumping chambers is partially bypassed through a bypass passage formed between the cam ring and the pump thrust plate. The bypass passage is urged to the open position by a bypass spring which urges separation between the cam ring and the thrust plate. The pressure plate of the pump responds to system pressure or demand to urge the cam ring into abutment with the thrust plate thereby reducing the opening and decreasing the bypass flow.

Abstract: A bearing and seal assembly for use in a hydraulic pump has a housing with a stepped outer diameter. The smaller diameter encloses a roller bearing and is adapted to sealingly seat in the pump housing. The larger diameter is disposed within the pump housing and encloses a seal member adapted to sealingly contact a stationary internal pump component so as to cooperate therewith in sealing against leakage of high pressure fluid from the pump. A shoulder between the stepped diameters abuts a radial inner wall of the pump housing. The high pressure fluid within the pump acts on the seal end of the assembly thereby urging the shoulder to remain in abutment and assist in sealing against fluid leakage.

Abstract: A vacuum pump having a cam actuated spring-biased pumping element and a gear for rotatably driving the cam has a torque counterbalancing spring and plunger device engaging the cam in a position out of phase with the pumping element and arranged to apply counterbalancing torques that prevent the application of torque reversals to the gear and thus avoid gear oscillation and chatter.

Abstract: Power steering gear with integral rotary valve for directing hydraulic pressure fluid to and from a hydraulically actuated rack piston nut drivingly connected to an output and in which an internal spring device effectively reduces lash in the threaded connection between the worm and rack piston nut so that the valve components will be immediately relatively rotated on stub shaft input from the handwheel for improved and quicker valve response.