GB1298394A - Rotary positive-displacement pump - Google Patents

Abstract

1298394 Rotary positive-displacement pumps TOYODA KOKI KK 19 March 1970 [1 April 1969] 13266/70 Heading F1F An hydraulic pump has spring-loaded abutments 23 slidingly engaging with a cam ring 20 fixed to a rotary shaft 18, which is provided with suction and delivery channels 27, 29 that communicate with recesses 26, 28 in said ring. Notches 23a give the working fluid access to the outer sides of the abutments; and grooves 31, 32 at the leading edges of the recesses minimize pressure pulsations. The working fluid is stored in a reservoir 34. Discs 14, 15 are loaded by pressure transmitted from the channel 29. The out-going fluid is directed from the channel 29 to a delivery port 41 by way of a passage 39 and the throat 47 of a Venturi passage formed in a spring-loaded valvemember 44, the pressure at said throat being transmitted to a chamber 44a through passages 48, 49. In accordance with the pressure differential between its ends the member 44 allows a proportion of the fluid to return to the reservoir by way of a port 51 and thus renders the flow through the port 41 substantially constant. When a pilot pressure-relief valve comprising a spring- loaded ball 53 opens the member 44 is displaced so as to increase the flow through the port 51. A second embodiment, Figs.4 and 5 (not shown), differs mainly in that the Venturi passage is located apart from the valve member. A third embodiment, Figs.8 to 10 (not shown), differs chiefly in that a reservoir for the fluid is either mounted on top of the housing 10 or situated separately from the remainder of the pump and the fluid flows from the reservoir to the channel 27 by way of the port 51, the valve member being generally similar to that shown in Figs.2 and 3.