GB1304723A - - Google Patents

Abstract

1304723 Rotary pumps EATON CORP 4 Sept 1970 [5 Sept 1969] 42444/70 Heading F1F In a hydraulic pump assembly 20 comprising roller vaines 74 acting against a substantially elliptical cam ring 54, intake passages 58, 60, which feed fluid to diametrically opposite portions of the pump via openings 111, 112 in cheek plates 114, 116, Fig. 8, have progressively increasing cross-sections in the direction of fluid flow. Fluid is fed to the inlet ports 96, 98 of the intake passages 58, 60 from a reservoir (28) Fig.1-3 (not shown) adjustably mounted on the pump assembly 20, and is delivered via openings 128, 130 in cheek plates 114, 116 to an annular discharge duct 134, and thence via passages 138, 142, Fig. 13, to a line 22 leading to a main load circuit e.g. a power-steering assembly, or, when the latter is shut off, via a relief valve (214) Figs.14, 15 (not shown) to a line 24, Fig.4 leading to a coder unit, the fluid returning to the reservoir via a filter assembly (32) Fig. 2 (not shown). The pump output is maintained substantially constant throughout its range by a flow control valve 148, which comprises a spool (162) subjected on one side to the output pressure in passage 138, and acted upon the other side by a spring 158 and the pressure of fluid supplied to space 160 by bores 200, 202 from the throat portion 192 of a convergent-divergent nozzle 188 mounted in passage 142. The fluid pressure in the throat portion 192 drops as the flow increases until the pressure of fluid in passage 138 overcomes the effect of spring 158 and the fluid pressure in space 160, and spool 162 moves to connect discharge passage 138 to intake passages 58, 60 via openings 170, 172, Fig.4. In order to operate with both clockwise and anti-clockwise drive assemblies, the cheek plates 114, 116, the cam ring 54 and the rotor assembly 66 may be removed from the housing and their positions on the drive shaft 68 reversed. To this end, a securing ring 260, Fig. 8, may be unscrewed and an end plate 146 removed. Leakage from the outlet openings 111, 112 in cheek plates 114, 116 is prevented by seals 144 which also serve to define pressure loading areas for the cheek plates. Rotation of the cheek plates 114, 116 and the cam ring 54 is prevented by a pin 240 Fig.4 engaging notches in the peripheries thereof and fixed at its ends in the pump housing and the end plate 146.