GB1165465A - Improvements in or relating to Rotary Power Steering Pumps - Google Patents

Abstract

1,165,465. Rotary pumps. TRW Inc. June 27, 1967 [Dec. 22, 19661, No. 29664/67. Heading F1F. A rotary pump of the rocking-sliding slipper type comprises a plurality of axially aligned parts including a housing plate 20, Fig. 3, a pumping cartridge element 16, a pressure plate 17 and a cover plate 18 maintained in axial alignment with each other by bolts 21 and dowels 47, Fig. 5, and a thin sheet-form member 26 surrounding the pumping cartridge and the pressure plate to form an inlet zone I with the whole enclosed in a thin walled cap-shaped member 11 forming a reservoir R. The pumping cartridge 16 comprises a ring member 30 having an oval bore 32 abutted in two places by a rotor 32 to form a pair of diametral pumping chambers 33 and a plurality of spring- loaded slippers 40 radially and rockably movable in axially-extending peripheral notches 35 in the rotor. Hydraulic fluid from the zone I is admitted to the pumping chambers 33 through ports 34 and to the notches 35 through openings (not shown) and discharged at pressure therefrom axially through major and minor outlets 53, 54 respectively in the pressure plate 17 to a recess 57 in the cover plate 18 so that discharge pressure acts on the rear face of the pressure plate to urge the pressure plate 17 pumping cartridge 16 and housing plate 20 into sealing engagement. Pump discharge passes from the recess 57 through a port 55 in the pressure plate to an outlet chamber O and thence through an orifice 59, Fig. 2, and a passage 58, 62, 63, 64, 65 to a utilization point. Pump discharge pressure upstream and downstream of the orifice 59 acts on the opposite ends of a spring-loaded plunger 74 controlling ports 88 leading to the low pressure zone I. On rightward movement of the plunger, Fig. 3, hydraulic fluid is sucked into the zone I from the reservoir R through ports 90, 89. A spring-loaded loose ball valve 84 co-operating with a seat 85 which is a press fit in the plunger relieves excess pressure through radial ports (not shown), an annulus 87 and the ports 88.