GB1312432A - Hydraulic rotary positive displacement pump - Google Patents

Abstract

1312432 Rotary positive-displacement pumps ROBERT BOSCH GmbH 11 Jan 1971 [2 April 1970] 1224/71 Heading F1F In an hydraulic pump of the outwardly-sliding- vane type a ring 16 is mounted pivotally on a fixed pin 17 so that its eccentricity can be varied and in combination with a housing member 12 and end covers 10, 11 defines a chamber 13 above throttling gaps 26, 27. Inlet and outlet recesses 28, 29 are formed in an end cover member 11. As fluid flows to a discharge port 31 from the recess 29 by way of a recess 30 and the chamber 13, the pressure differential across the gaps 26, 27 urges the ring 16 away from a stop 22 against the action of a spring 23, the flow rate at the port 31 being thus rendered substantially constant irrespective of the speed of the rotor 15. A piston 34 to which pressure is transmitted from the port 31 prevents movement of the ring 16 in response to pressure changes on the high-pressure side of the rotor. Axial pressures are balanced by provision of a recess 30'. In a modification, Fig. 3, the piston 34 is replaced by a piston 40 with a separated spring-loaded extension 43, the spring 23 being dispensed with. When open a pressure-relief valve 47 inter-connects a chamber 45 and the lowpressure side of the pump. In other embodiments, Fig. 4 to 7 (not shown), the ring is movable transversely relative to the rotor axis and an adjustable throttle is provided, in the housing member, Fig. 4; the ring has diametrically opposed pins mounted in the housing so as to be movable as in the Fig. 4 embodiment and two pressureloaded pistons prevent the ring tilting, Fig. 5; the ring has diametral slots engaging with fixed axial pins or rollers so as to be movable as in the Fig. 4 embodiment, Fig. 6; and the ring has a throttle therein and engages with sealing members in place of the gaps (26), (27), Fig. 7.