Abstract: When oil flows from within a seat valve along an oil path in a valve, structure is such that a negative pressure is generated to draw a ball in the direction of the seat valve. That is, the force in the direction of valve closure is actively utilized, the valve does not perform a full stroke in a certain differential pressure range, and increases in a pulsed manner in a minute-stroke state, i.e., in a state where the passage cross-sectional area of the valve is small. Therefore, effective control becomes possible without a large pressure increase.

Abstract: A hydraulic brake control system for a vehicle includes a return line for reducing a pressure built up in a wheel cylinder. The return line includes therein a switching valve for opening and blocking the return line. The return line further includes therein cylinders each having therein a piston for defining a piston chamber therein. Each piston has a first state where a brake fluid flowing from the wheel cylinder via the switching valve is allowed to flow into the piston chamber, and a second state where the brake fluid is allowed to be discharged from the piston chamber so as to be returned to a master cylinder. An operation control mechanism is provided for controlling the pistons into the first states and the second states, respectively, at different timings from each other in turn.

Abstract: A radial piston pump has a rotor provided within a cylinder chamber in such a manner that a center axis of the rotor is offset from a center axis of the cylinder chamber. The rotor has three working chambers a piston is slidably provided each of which. Each working chamber may connect with a suction groove or a discharge groove so that there exists a couple of situations, one of which is that two working chambers connect with the discharge chamber simultaneously and another one of which is that single working chamber connects with the discharge chamber. In order to make the forcing point at which total biassing force of the piston is focussed move gradually, the radial piston pump has a delay angle at a front side of the suction chamber. Namely a pressure within the working chamber is preliminary reduced before the working chamber connects to the suction groove so that the forcing point should shift gradually.

Abstract: An electromagnetic relay installed in an automobile. In this electromagnetic relay, a casing to house an electromagnetic coil therein is used as part of a magnetic circuit for reducing the size and weight of the electromagnetic relay. By doing this, there may be provided an electromagnetic relay whose construction is well adapted for use in automatic mechanical assembly of the relay.