Pressure control valve for power steering mechanism

摘要

The valve is made up of an aluminium body (1) with a pump port (P), an actuator part (4a) and a secondary orifice (B). A hole (2) is provided at the centre of the aluminium body. A spool part (3) made up of aluminium is inserted into the hole. The spool consists of a relief valve with a spring (13) and a steel ball (15). A rod (8) is fitted inbetween the spring and a connector (4) forms a variable orifice (9). The oil with pressure comes to the variable orifice through a pump port reaching a pressure chamber (5) of the spool via a set of downstream passages (11-12). When the oil pressure exceeds the spring pressure of the spool, it presses a steel sleeve (18) into an inserted seat member (16) of the steel ball. This results in movement of rod and closes the variable orifice. Oil in the pressure chamber returns through the secondary idle orifice.