Abstract: In a solenoid valve, multiple flow-blocking portions are formed in a passage between a supply port (23) and an output port (24) and a passage between the output port (24) and a drain port (25). The flow-blocking portions, having an overlap length that corresponds to the movement amount of a spool (30), are formed by the outer peripheral faces of lands (32, 33) and the inner peripheral face of a spool case (10).

Abstract: In a solenoid valve, multiple flow-blocking portions are formed in a passage between a supply port (23) and an output port (24) and a passage between the output port (24) and a drain port (25). The flow-blocking portions, having an overlap length that corresponds to the movement amount of a spool (30), are formed by the outer peripheral faces of lands (32, 33) and the inner peripheral face of a spool case (10).

Abstract: A solenoid valve comprises a solenoid portion 10 and a valve portion 20. The solenoid portion 10 is constructed by a stator core 12, an electromagnetic coil 14 and a plunger 15. The valve portion 20 is constructed by a valve sleeve 21 and a spool 25 axially forming plural lands 26a-26c in series. The plunger 15 is axially moved by electromagnetic attraction and drives the spool 25. There are formed the same pressurized areas at the plunger 15 and the land of the spool 25 closest to the plunger 15. Therefore, the volume in an intermediate space B between the plunger 15 and the spool 25 is constant and contaminants in the oil are not sucked into the intermediate space B.

Abstract: In a solenoid valve 10, an annular oil groove 66 is formed at a portion corresponding to a spring chamber 56 on the external surface of a sleeve 19, a drain passage 68 is formed to make an upper part of the annular oil groove 66 communicate with the outside of an insertion bore 61, and a throttle hole 67 is provided at a lower part of the annular oil groove 66 for making the annular oil groove 66 communicate with the spring chamber 56. Since the annular oil groove 66 communicates with the outside of the insertion bore 61 at its upper part through the drain passage 68, it can be realized to store the operating oil to the height of the upper part of the annular oil groove 66, so that the operating oil can be reserved in the spring chamber 56 which communicates with the annular oil groove through the throttle hole 67. Further, the operating oil is supplied from a feedback port 48 next to the spring chamber 56 through a clearance between the spool valve 19 and a valve hole 18.

Abstract: In a solenoid valve 10, an annular oil groove 66 is formed at a portion corresponding to a spring chamber 56 on the external surface of a sleeve 19, a drain passage 68 is formed to make an upper part of the annular oil groove 66 communicate with the outside of an insertion bore 61, and a throttle hole 67 is provided at a lower part of the annular oil groove 66 for making the annular oil groove 66 communicate with the spring chamber 56. Since the annular oil groove 66 communicates with the outside of the insertion bore 61 at its upper part through the drain passage 68, it can be realized to store the operating oil to the height of the upper part of the annular oil groove 66, so that the operating oil can be reserved in the spring chamber 56 which communicates with the annular oil groove through the throttle hole 67. Further, the operating oil is supplied from a feedback port 48 next to the spring chamber 56 through a clearance between the spool valve 19 and a valve hole 18.

Abstract: Disclosed is a solenoid-operated valve which is capable of enhancing the responsivety of a device while an electric current applied thereto is in a low current range, and which is capable of preventing the device from vibrated by the fluid pressure fluctuation while in a high current range. A spool is received in a valve sleeve for regulating the pressure of fluid. A plunger is received in a stator that has a core provided with an annular projecting portion. A solenoid magnetizes the stator to attract the plunger so as to move the plunger into the annular projecting portion. The annular projecting portion is formed with a tapered portion and a thin cylindrical portion projecting from the rear end of the tapered portion. A step is formed on the outside of the annular projecting portion between the tapered portion and the thin cylindrical portion.

Abstract: Disclosed is a solenoid-operated valve which hardly brings a plunger into a lock and is capable of improving its responsivety. In the solenoid-operated valve, the plunger slidably guided in an inner bore formed in a yoke and a core aligned axially is moved by energizing an electromagnetic coil, and a spool in a valve section is moved through a rod portion which protrudes from an end of the plunger to pass through a center hole of the core. An electromagnetic section fluid chamber defined by a forward end surface of the plunger and the inner bore of the core communicates with an intermediate fluid chamber defined between the core and a valve sleeve, through a clearance between the center hole and rod portion. The spool is provided at one end thereof with a land portion whose end surface defines a part of the intermediate fluid chamber.

Abstract: A solenoid valve comprises a solenoid portion 10 and a valve portion 20. The solenoid portion 10 is constructed by a stator core 12, an electromagnetic coil 14 and a plunger 15. The valve portion 20 is constructed by a valve sleeve 21 and a spool 25 axially forming plural lands 26a-26c in series. The plunger 15 is axially moved by electromagnetic attraction and drives the spool 25. There are formed the same pressurized areas at the plunger 15 and the land of the spool 25 closest to the plunger 15. Therefore, the volume in an intermediate space B between the plunger 15 and the spool 25 is constant and contaminants in the oil are not sucked into the intermediate space B.

Abstract: An electromagnetic drive device for lineally reciprocatilvely moving an operating member like a spool of a spool valve is reduced in the manufacturing cost without being degraded in its operational performance. In the electromagnetic drive device, a stator body is excited by an electromagnetic coil to axially move a plunger guided in an inner bore of the stator body, against the resilient force of a spring. The stator body is constituted by arranging a plurality of core portion annular plate elements made of a magnetic material, a plurality of yoke portion annular plate elements made of a magnetic material and a plurality of non-magnetic portion annular plate elements made of a non-magnetic material and placed between the core portion annular plate elements and the yoke portion annular plate elements and by piling up and bodily joining these annular plate elements in axial alignment with one another.

Abstract: Disclosed is a solenoid-operated valve which hardly brings a plunger into a lock and is capable of improving its responsivety. In the solenoid-operated valve, the plunger slidably guided in an inner bore formed in a yoke and a core aligned axially is moved by energizing an electromagnetic coil, and a spool in a valve section is moved through a rod portion which protrudes from an end of the plunger to pass through a center hole of the core. An electromagnetic section fluid chamber defined by a forward end surface of the plunger and the inner bore of the core communicates with an intermediate fluid chamber defined between the core and a valve sleeve, through a clearance between the center hole and rod portion. The spool is provided at one end thereof with a land portion whose end surface defines a part of the intermediate fluid chamber.

Abstract: An electromagnetic drive device for lineally reciprocatilvely moving an operating member like a spool of a spool valve is reduced in the manufacturing cost without being degraded in its operational performance. In the electromagnetic drive device, a stator body is excited by an electromagnetic coil to axially move a plunger guided in an inner bore of the stator body, against the resilient force of a spring. The stator body is constituted by arranging a plurality of core portion annular plate elements made of a magnetic material, a plurality of yoke portion annular plate elements made of a magnetic material and a plurality of non-magnetic portion annular plate elements made of a non-magnetic material and placed between the core portion annular plate elements and the yoke portion annular plate elements and by piling up and bodily joining these annular plate elements in axial alignment with one another.

Abstract: Disclosed is a solenoid-operated valve which hardly brings a plunger into a lock and is capable of improving its responsivety. In the solenoid-operated valve, the plunger slidably guided in an inner bore formed in a yoke and a core aligned axially is moved by energizing an electromagnetic coil, and a spool in a valve section is moved through a rod portion which protrudes from an end of the plunger to pass through a center hole of the core. An electromagnetic section fluid chamber defined by a forward end surface of the plunger and the inner bore of the core communicates with an intermediate fluid chamber defined between the core and a valve sleeve, through a clearance between the center hole and rod portion. The spool is provided at one end thereof with a land portion whose end surface defines a part of the intermediate fluid chamber.

Abstract: A pressure switch includes a switch housing which has an accommodation bore extending inward from one end of the switch housing, and a slide bore extending between the accommodation bore and the other end of the switch housing. A piston is slidably disposed within the slide bore and is adapted to receive a pressure. A terminal serving as one electric contact is fixed to the accommodation bore via a holding ring made of an insulating material. A disk spring serving as the other electric contact is disposed between the piston and the terminal. The disk spring deforms due to a pressing force of the piston and comes in contact with the terminal. The pressure switch further comprises an annular elastic ring placed on the outer end of the holding ring. An end portion of the switch housing is deformed inward so as to elastically deform the elastic ring, thereby sealing the opening portion of the accommodation bore.