SPOOL STRUCTURE OF PRESSURE CONTROLLING VALVE FOR VEHICLE HYDRAULIC STEERING SERVOMECHANISM

摘要

PURPOSE: A spool structure of a pressure controlling valve for a vehicle hydraulic steering servomechanism makes the flow of hydraulic pressure slow and reduces various noises by making a small diameter portion on the middle thereof and flattening the edges thereof. CONSTITUTION: A pressure controlling valve is operated according to vehicle speed when a left/right steering servo force is applied by a rotary valve(10) on running. Then, a spool(21) in a space portion is longitudinally moved and controls the flow rate from an inlet to an outlet. Then, the flow passes through the periphery of a filter material(7) wound around a small diameter portion(21a), or a coil spring(7a). Thus, no vortex flow is generated though the flow is passed with a large incidence angle. Therefore, the generation of noises is prevented.