Abstract: A flow control valve includes a valve body having a substantially cylindrical bore, and a substantially cylindrical valve element received within the cylindrical bore of the valve body to be reciprocatable. The valve body and the valve element define first and second chambers separated by the valve element. The valve body has a circumferential groove surrounding the valve element, and a plurality of radially-extending passage holes communicating with the circumferential groove. The circumferential groove and the passage holes form portions of the second chamber. The valve element has a plurality of radially-extending throttle holes for establishing communication between the circumferential groove and the first chamber. The flow rate of operation oil flowing between the first chamber and the second chamber via the throttle holes is changed through axial movement of the valve element.

Abstract: A variable-displacement vane-pump has a rotor which is rotatably supported by a pump housing in coaxial relationship therewith, and a cam ring interposed between the rotor and the pump housing in eccentric relationship with the pump housing. The rotor has radially outwardly slidable vanes on its outer peripheral surface in contact with an inner surface of the cam ring. Two side plates are disposed on both sides of the vanes, thereby defining pump chambers between every adjacent vanes. An arc-shaped intake port and an arc-shaped exhaust port are formed in one of two side plates, and respectively open into the pump chambers along one side face of the cam ring. In the other side face of the cam ring, a groove is formed except for the region corresponding to the exhaust port, and a partially cut off annular friction ring is disposed within the groove while urged by a seal ring into close contact with the other side plate.