| 摘要 |
<p>The flow control device or valve used in a power steering system of an automotive vehicle. A housing (1), an axially extending hole (H) in which a spool valve (14) is movable. A first pressure chamber (15) is defined in the hole, with one end of the spool valve. A drain passage (19) is opened to the first pressure chamber and closable with the spool valve. A second pressure chamber (16) is defined in the hole, with the other end of the spool valve. A restricting orifice (9) communicates with the first pressure chamber (15). An introduction passage (20) communicates through the orifice (9) with a discharge passage (8) and is opened to the first pressure chamber (15). The pressure in the discharge passage (18) is introduced via communication passages (21,25) to the second pressure chamber (16). A first spring (17) is disposed in the second pressure chamber (16) to bias the spool valve in a direction to close the drain passage (19). A spring holding member (37) movably and coaxially disposed in the hole (H) has a first end face (40) defining the second pressure chamber (16) and a second end face (41) which is larger in pressure-receiving area. The first spring (17) is disposed between the spool valve and the first end face (40). The second end face (41) defines a pressure control chamber (36) communicated with the second pressure chamber (16). Additionally, a second spring (48) is provided to bias the spring holding member (37) in a direction to reduce the volume of the pressure control chamber (36). <IMAGE></p> |
