Durchfluss-Regeleinrichtung für eine Servolenkung

摘要

In a power steering system which has a fluid pump and a hydraulic actuator, there is used a flow control device (100) which comprises a spool unit (50) slidably received in a spool receiving bore (5) in a manner to partition the bore into first (15) and second (16) pressure chambers. The spool unit (50) comprises a hollow cylindrical outer spool (52) slidably received in the spool receiving bore. The outer spool (52) has a bottom portion (52b) exposed to the second pressure chamber. The bottom portion has an aperture formed therethrough. A cylindrical inner spool (51) is incorporated with the outer spool. The inner spool includes a larger diameter portion (51a) slidably received in a major part of the outer spool and a smaller diameter portion slidably received in the aperture of the bottom portion (52b) of the outer spool. The inner spool is engaged with a control spring (17) to be biased toward the first pressure chamber. A spring member (61) is employed for biasing the outer and inner spools toward the second and first pressure chambers respectively.