Regulator for engine-driven hydro-pump of variable supply volume

摘要

The regulator operates on the reversible hydro-pump (2), which is connected to the tank (9) via a suction line (8) and to a hydro-motor (not shown) via two working lines (10,11) in a closed loop, and is driven by the vehicle engine (1) with hydrostatic transmission. An auxiliary pump (18) mechanically coupled by a shaft (17) produces a volume flow directly proportional to the rotational speed of the engine. A regulator valve (19) has a measuring constriction (20) developing a pressure difference from which a speed-related control pressure (p3) is produced in a line (26) to an adjustor (4) of the pump volume. The line passes through a three-port two-position valve (21) operated by an engine-speed-dependent signal (36). An electrically operated 4/3 way valve serves as a reversible i.e direction of travel valve (5), and the hydro-pump (2) feeds a pressure medium through a working line (10) or (11) to the hydro-motor (not shown) so that the vehicle travels in a direction corresp. to the control of the reversible i.e. direction of travel valve (5).