Solenoid operated oil metering pump - has oscillating piston valve intermittently connecting cylinder with metering piston to inlet and outlet

摘要

The arrangement is intended for variably supplying liquid preferably oil, for the control of e. g. an hydraulic motor. It has a control element (10) consisting of two interconnected pistons which are moved to and fro and, in the rest position, are held in a mid-position relative to an oil inlet (8). In this position, the pistons close ducts (25, 28, 26, 29) leading from the two sides of a cylinder (4) with metering piston (5) to an outlet (27). When the element moves from the rest position, one duct (25) is connected with the inlet (8) whilst the other (26) is connected with the outlet (27). On each side of the control element (10) is an inwardly acting spring (17, 18) thw two springs exerting equal pressure. The pump is operated alternately by the solenoids (21, 22).