Oil pressure drive for vehicle with hydraulic steering and engine cooling - has engine-driven variable delivery pump supplying steering servo and hydraulically impelled engine cooling fan via distributor valve

摘要

A fluid pressure drive system for a vehicle has a reservoir (12), an engine (90) driven variable delivery oil pump (11) and associated delivery control circuitry (21, 22, 26, 28, 91) defined by the rectangle (23). A distributor valve (32) divides the oil entering via the conduit (14) into the outlet channel (33) supplying the power-steering servo (36) and the channel (34) driving a hydraulic motor (38) which propels the engine (90). The oil delivery and pressure are controlled within a regime which ensures that the hydraulic drive (38) to the fan (39) is maintained in consistency with the engine (90) temp. independently of the increased demand imposed by steering requirements at standstill or low speeds. ADVANTAGE - Ensures engine is adequately cooled at all times irrespective of demands made by servo-steering system.