Abstract: An electromagnetic proportional pressure control valve includes a housing, and a spool slidably received in the housing. The spool has a pair of first and second pressure receiving portions which are equal to each other in effective pressure receiving area. A primary pressure in a primary port is applied to the first pressure receiving portion, and a secondary pressure in a secondary port is applied to the second pressure receiving portion. A form due to the primary pressure acts on the spool in a direction to increase the secondary pressure, and a force due to the secondary pressure acts on the spool in a direction to decrease the secondary pressure. A force of a spring and a force of an electromagnetic actuator also act on the spool in the opposite directions. A variation in the primary pressure directly appears in the secondary pressure.

Abstract: A spool valve has a valve housing with a valve bore formed therein, a spool having a land portion slidably accommodated in the valve bore, a control port formed within the valve housing, able to communicate with the valve bore, and opened and closed by the land portion, and an annular groove open at an inner peripheral surface of the valve bore and communicating with the control port. Part of the control port is open over the inner and outer parts, as taken in the widthwise direction, of the annular groove. The degree of opening of the port is variably controlled by the displacement of the land portion.

Abstract: An electromagnetic actuator includes a housing and a pair of stators cooperating with the housing to form a magnetic circuit for a solenoid. Each of the pair of stators has a tubular portion, and the tubular portions of the pair of stators have their one ends disposed in the opposed spaced relation to each other. The solenoid is mounted around the tubular portions of the pair of stators, and an armature is received in the tubular portions of the pair of stators so as to be movable along the axis of the tubular portions. The armature is supplied with a force when an electric current is applied to the solenoid. In order to keep the magnetic resistance of the magnetic circuit to a low level, one of the pair of stators is formed integrally with one end of a tubular body of the housing so that the housing and the one stator constitute a unitary member.

Abstract: An electromagnetic proportional control valve apparatus comprises a valve body, a spool accommodated in a guide bore in the valve body, a valve seat element arranged at one end of the guide bore and facing toward the spool, a pilot valve controlling a valve bore in the valve seat element, and an electromagnetic drive unit for controlling the pilot valve. The spool has an axially extending axial bore formed in an end face opposed to the valve seat element, and a first restricting bore through which the axial bore communicates with the supply port. A projecting portion is formed on an end face of the valve seat element opposed to the spool, and is inserted in the axial bore in the spool. The projecting portion has a forward part formed therein with second restricting bores through which one end of the valve bore communicates with the axial bore. A restricting passage is defined between an outer peripheral surface of the projecting portion and an inner peripheral surface of the axial bore in the spool.

Abstract: In an electromagnetic control valve, a pair of spools are accommodated within a guide bore in a housing in coaxial relation to each other for axial movement relative to the housing. First and second flow passageways are formed in the housing. Flow of hydraulic fluid through the first flow passageway and flow of hydraulic fluid through the second flow passageway are controlled respectively by the pair of spools independently of each other. Movements of the respective spools are controlled respectively by a pair of electromagnetic drive units independently of each other. The pair of spools have their respective inner ends facing toward each other. The inner ends are spaced away from each other when the pair of spools are in their respective initial positions. Moving regions of the respective inner ends are at least partially overlapped with each other.

Abstract: An electromagnetic valve comprising a housing provided with a supply port, at least one control port and a discharge port, and a valve member accommodated movably in the housing. The housing is formed therein with first and second opposed valve seats extending perpendicularly to the axis of the valve member. The valve member has first and second abutment faces extending perpendicularly to the axis of the valve member. The first and second abutment faces are opposed respectively to the first and second valve seats. The valve member is movable between a position where the second abutment face is abutted against the second valve seat to intercept communication between the control port and the discharge port, and a position where the first abutment face is abutted against the first valve seat to intercept communication between the control port and the supply port.

Abstract: A solenoid valve in which the displacement of a spool slidably contained within a valve bore of a valve body is controlled by means of the displacement of a plunger slidably contained within a plunger chamber, one end of the valve bore communicating with the plunger chamber being blocked, the valve body being provided therein with an oil reservoir chamber communicating with the valve bore, and the oil reservoir chamber being communicated with the plunger chamber.

Abstract: A hydraulic pressure controller including a valve body having a longitudinal bore and defining an inlet port for connection to a hydraulic pump, an outlet port for connection to a hydraulically operated device, a discharge port for connection to a hydraulic fluid reservoir and a cylindrical end portion surrounding a portion of the longitudinal bore, with the ports opening transversely into the longitudinal bore. Also included is a valve spindle axially movable in the longitudinal bore between positions that provide flow passages between the inlet, outlet and discharge ports; an electromagnet having a solenoid winding, a fixed magnetic core, and a cylindrical plunger movable within the winding and axially aligned and engageable end-to-end with the valve spindle; and a cylindrical guide tube having an open ended length portion fitted over the cylindrical end portion and another length portion slidably fitted over the plunger.