Abstract: The Disclosed is a solenoid valve, in which a rod is moved by a plunger that comes into contact with and separates from a stator by electromagnetic force, causing a valve body that opens and closes a valve to move reciprocally. The valve is configured such that a first space and a second space are formed at respective sides of the plunger in the movement direction thereof, a through-hole is formed in the plunger so as to be concentric with a center axis, the rod is arranged in the first space, and a communication passage is formed between an inner surface of the plunger and an outer surface of the rod and communicates with the first space S1 and the second space.

Abstract: A suction valve of a high-pressure fuel pump for a vehicle includes a housing having an inlet through which a fuel is introduced and a pump chamber configured to press the fuel, a valve installation space arranged between the inlet and the pump chamber, and a solenoid part provided with a rod for performing a linear reciprocal motion, and further includes a valve sleeve inserted into the valve installation space and formed with a flow hole, a valve spring seated on the valve sleeve, a valve plate elastically supported by the valve spring, and moving in conjunction with the rod, and a valve sheet formed with an introduction hole opened and closed by the valve plate, in which the valve sleeve is slid and inserted into the valve installation space, and the valve sheet is fitted into and fastened to the valve installation space to support the valve sleeve.

Abstract: A drain tool assembly adapted to couple to a housing without causing fluid to flow from the housing until moved to a draining position. The drain tool assembly avoids fluid spillage by sealing a body to the housing and then engaging a plunger of the housing by moving and locking a sleeve to initiate a flow of fluid from the housing.

Abstract: When a rotating body is oriented at a default position due to the absence of a driving force, a first hook portion and a second hook portion are engaged with a fixed engagement portion and/or a movable engagement portion. When the rotating body is rotated from the default position by the driving force, the first hook portion is engaged with one of the fixed engagement portion and the movable engagement portion, and the second hook portion is engaged with the other of the fixed engagement portion and the movable engagement portion. A throttle valve device includes a pressing portion that presses the first hook portion and/or the second hook portion to apply a pressing force toward a center of a coil portion in a coil axial direction.

Abstract: An assembly and method of assembling a butterfly control valve assembly (such as a throttle body or exhaust gas recirculation valve) having a metal valve shaft with a valve. A plastic end cap is secured into an end of the metal shaft. A plastic valve gear housing is laser welded to the end cap.

Abstract: Equipment for fluid transfer includes a valve, a frame that defines a housing for the valve and an upstream passage for the fluid that leads into the housing and is fluidically connectable to a fluid source, the valve being able to move between a non-inserted position and an inserted position in which the valve is situated at least partially in the housing, a module that defines a downstream passage for the fluid that fluidically connectable to the reservoir, the module being able to move between an open position, allowing the insertion of the valve, and a closed position in which the module is fixed to the frame, and two seals that are respectively compressed substantially between the valve and the frame and between the valve and the module when the valve is in the inserted position and the module is in the closed position.

Abstract: A valve piece urging member urges a valve piece toward a valve closing side, at which an opening degree of a restriction passage is reduced by the valve piece. An actuation member exerts a drive force against the valve piece in a direction of moving the valve piece toward a valve opening side, at which the opening degree of the restriction passage is increased by the valve piece. A vibration limiting member limits vibration of the valve piece in a direction, which intersects with the axial direction, by generating an urging force for urging the valve main body at a location between the valve main body and the valve piece. When the valve piece is moved beyond a predetermined displacement position toward the valve opening side, the valve piece releases the urging force of the vibration limiting member.

Abstract: A fixing shaft portion of a valve shaft is fixed to a throttle valve at first and second locations by first and second fixing members. A first bearing includes an inner race fixed to a first rotatable shaft portion of the valve shaft, and an outer race fixed to a valve body. A second bearing includes a slidable portion axially slidably fitted to a second rotatable shaft portion of the valve shaft and a fixing portion fixed to the valve body. A linear expansion coefficient of the throttle valve and a linear expansion coefficient of the valve body are set to be larger than a linear expansion coefficient of the valve shaft in an axial direction. A first distance measured from a center point of the throttle valve to the first location is larger than a second distance measured from the center point to the second location.

Abstract: A check valve comprises a valve seat element along a fluid path that is formed of a polymeric material and comprises a hole that extends from an input end of the valve seat element to an output end of the valve seat element. The valve seat element includes an inner taper that transitions the input end to the output end, the valve seat element including a sealing surface along the inner taper. A poppet body is formed of a polymeric material and configured to engage the internal tapered sealing surface of the valve seat element. The poppet body moves between a first position at which the poppet body sealingly engages the tapered sealing surface of the valve seat element and a second position at which the poppet body is separate from the inner taper of the valve seat member.

Abstract: A solenoid valve includes a housing, having an inlet and an outlet, wherein the solenoid valve also includes a valve element and a valve seat. To provide a solenoid valve to be used with high maximum operating pressure differences between inlet and outlet, the solenoid valve includes at least one progressive spring, wherein the valve element is forced by the at least one progressive spring. Thereby, the spring force acting on the valve element in the closed position of the valve may be decreased, while still retaining a large spring force in the opened position of the solenoid valve.

Abstract: An object of this invention is both to prevent contamination of a fluid passing a fluid control valve and to prevent a tilt of a valve body in a moving direction and vibration of the valve body. The fluid control valve comprises a valve body that is arranged on an inner surface of a valve chest through a predetermined space in the valve chest and that is arranged on a valve seat arranged in the valve chest in a detachable manner, an actuator that biases the valve body in a direction of opening the valve, a valve body return spring that biases the valve body in a direction of closing the valve, and a tilt restraining spring that biases the valve body in a direction of resolving a tilt of the valve body to an open/close direction.

Abstract: Methods and apparatus for changing actuator output torques are disclosed. An example method includes decoupling a first end cap from a body of an actuator. A first spring assembly is positioned within a first outer chamber defined by the first end cap and the body. A first end of the first spring assembly is positioned adjacent a surface of a first piston. A second end of the first spring assembly is positioned adjacent the first end cap when the first end cap is coupled to the body. The method includes positioning a first spacer within the first outer chamber and coupling the first end cap to the body. The first spacer changes a distance between the first and second ends of the first spring assembly when the first end cap is coupled to the body to change an output torque of the actuator.

Abstract: In one featured embodiment, a spring assembly for a valve comprises a spring, a spring seat including a cup-shaped portion for seating one end of the spring, and a ball received within a recess formed within the cup-shaped portion of the spring seat. The ball is defined by a ball diameter. A disc prevents the ball from contacting a piston. The disc is defined by an outer diameter and includes a center opening defined by an inner diameter. A ratio of the inner diameter to the ball diameter is between 0.60 and 0.65.

Abstract: A drain plug assembly that has particular application for sealing a drain hole in a high voltage battery compartment on a vehicle. The plug assembly includes a plug that inserted into the drain hole. The plug assembly further includes a return spring coupled to the plug and causing the plug to be biased into the drain hole. The plug assembly also includes at least one shape memory alloy device coupled to the plug and a support structure. The SMA device receives an electrical current that causes the device to contract and move the plug out of the drain hole against the bias of the return spring.

Abstract: The invention provides a switching valve having a valve element which is movable in a housing, an actuating apparatus acting on the valve element in a first direction and a spring apparatus charging the valve element in a second direction. According to the invention, the first and second directions are in opposition and the spring apparatus has a progressive spring characteristic.

Abstract: A technique provides a component actuation system in a space efficient form. A movable actuator member may be positioned within a corresponding housing in a manner which forms an annulus between the movable actuator member and the surrounding wall of the housing. A spring is located in the annulus and is designed such that the spring extends part way along a circumference of the actuator member to create an open annular region between circumferential ends of the spring. The open annular region provides space for a system related component without requiring additional longitudinal or radial space.

Abstract: A solenoid includes: a movable core configured to move in a first space of a main body case in an axial direction to apply a biasing force to a spool; a fixed magnetic pole portion configured to attract the movable core in the axial direction; an adjusting spring configured to apply the biasing force to the movable core; a biasing force adjusting member provided at an opening end portion of a rear case and configured to adjust an axial position thereof to adjust the biasing force; and a degassing plug provided at an opening end portion of the adjusting member and including a degassing passage that allows a second space to communicate with an outside by changing relative positions of the adjusting member and the degassing plug. A sealing portion configured to open or close communication between degassing passages is provided between the adjusting member and the degassing plug.

Abstract: An air compressor system includes a housing defining an inlet and an outlet, a butterfly valve coupled to the inlet and movable between a closed position and an open position, and an actuator coupled to the butterfly valve and operable to apply an actuator force to the butterfly valve to move the actuator and the butterfly valve to a desired position between the closed position and the open position. A feedback actuator is coupled to the actuator and is operable to apply a variable secondary force to the butterfly valve in opposition to the actuator force, the secondary force varying in response to the position of the butterfly valve.

Abstract: Actuator stem guide apparatus for use with fluid valve actuators are described. An example actuator stem guide apparatus includes a base having an opening to allow an actuator stem of the fluid valve actuator to tilt or lean within the base to enable a lever of the fluid valve actuator to rotate and a guide receiving area adjacent the opening of the base. A guide is coupled to the guide receiving area and the guide has a bearing surface to slidably engage the actuator stem to limit lateral movement of a diaphragm assembly relative to a longitudinal axis of the opening to prevent the diaphragm assembly from engaging an inner surface of an actuator housing as the actuator stem moves between a first position and a second position.

Abstract: A normally closed solenoid valve (100) includes a housing (10), and a valve element (21), a movable core (22), a first spring (23), a second spring (24), a coil (25), a stator core (26), and other components, which are assembled to the housing (10). The valve element (21) is arranged so as to be seatable on and unseatable from a valve seat (12c). The movable core (22) is assembled to a cylinder section (11b) of the housing (10) so as to be movable integrally with the valve element (21) in an axial direction of the movable core (22). The first spring (23) is configured to bias the valve element (21) and the movable core (22) toward the valve seat (12c). The coil (25) and the stator core (26) are configured to generate an electromagnetic force resistive to a load of the first spring (23) for the movable core (22) through energization of the coil (25).

Abstract: A rotation axis O2 of a shaft 3 is attached thereto with double-offset in the X and Y directions with respect to a center line O1 of a valve seat 2. A bevel process is implemented on the outer peripheral surface of a valve 1 such that the valve 1 and the valve seat 2 is line-sealed, and the sign of the angles of inclination is switched between plus and minus at two places of the outer peripheral surface of the valve 1 deviated from the center of the axis. Further, a section where the angle of inclination is constant is prepared in each of the sections connecting the two places, while the other sections are smoothly connected to each other.

Abstract: A pressure relief assembly may include an actuator stem having a plurality of retaining grooves. A relief plate may be operatively connected to the actuator stem and a diaphragm plate may be operatively connected to the actuator stem. A diaphragm may be least partially disposed between the relief plate and the diaphragm plate. A relief spring seat may be releasably attached to the actuator stem at one of the plurality of retaining grooves. The relief spring may be adjusted by moving the attachment point from one retaining groove to another retaining groove.

Abstract: An assembly for actuating a double-acting shift cylinder of a shift assembly of an automatic transmission of a motor vehicle includes a hydraulic fluid reservoir having a motor-driven hydraulic pump and two control valves that are each connected to a pressure supply line of the hydraulic pump and to a return line to the hydraulic fluid reservoir. The shift cylinder has two pressure chambers that are each connected to one of the control valves. The control valves each connect one pressure chamber of the shift cylinder to the pressure supply line of the hydraulic pump or to the return line to the hydraulic fluid reservoir. The actuating assembly includes at least one pressure-limiting valve that connects the pressure supply line to the return line if a hydraulic over-pressure is present. The control valves can be 3/2-directional valves having integrated pressure-limiting valves.

Abstract: An aperture-shaped variable valve which is used for a semi-active control. The variable valve includes a ring-shaped aperture frame, a plurality of aperture plates which is arranged in a ring shape by overlapping each other on the aperture frame and forms an aperture, a restoring ring which fits into the outside of an aperture surface, and a spring which is connected between the restoring ring and the aperture frame.

Abstract: A device in a valve (1) includes a valve housing (2) with at least a first (3) and a second (4) fluid port. A closure element (5) including a sealing portion (15) and diaphragm (30) is arranged in the valve housing (2). The sealing portion (15) is movable between an open position and a closed position. The closure element (5) and valve housing (2) form a flow passage (11) which communicates with the fluid ports when the sealing portion (15) leaves the closed position. A second sealing portion (14) is arranged in contact with a support portion (25) of the valve housing (2). An abutment element (16) is arranged in contact with the second sealing portion (14). The abutment element (16) transmits a force via the second sealing portion (14) toward the support portion (25) to provide a seal. The force is at least partly exerted by a spring element.

Abstract: A microvalve for controlling fluid flows, and a sealing device for sealing cavities in a microfluidic system, particularly in a lab-on-a-chip system, and a method for the production thereof. A sealing surface of a valve body, or a sealing element, respectively, rests on a sealing surface of a substrate and is pressed against the sealing surface of the substrate in a fluid-tight manner by means of a clamping element. The clamping element and/or the valve body, or the sealing element, respectively, are at least partially elastic.

Abstract: A valve according to an exemplary aspect of the present disclosure includes, among other things, a return spring. A latch mechanism includes a first magnet and a second magnet. One of the first and second magnets magnetically latches to the other first and second magnets in response to a control signal to minimize decompression of said return spring.

Abstract: A spring mounting cradle for an over-pressure valve assembly has integral valve-element camming surfaces provided adjacent the lower ends of a pair of the bent legs forming the cradle.

Abstract: A warming blanket is provided that includes a first sheet and a second sheet sealed at least along a common edge. An air inlet is provided on the warming blanket where the first sheet and the second sheet are not sealed. An inlet opening device is attached to the inlet opening. The inlet opening device separates the first sheet from the second sheet at the inlet opening in the absence of an opposing force. Methods of forming and using the warming blanket are also provided.

Abstract: A solenoid valve for controlling fluids includes a pole core, an armature which is connected to a closing element, and a spring element which is arranged in a working gap between the pole core and the armature. The spring element includes a shaped spring of substantially disk-shaped design. The shaped spring has a curvature with at least one flank region and one dome region, a tangent to the dome region being parallel to an end surface of the pole core.

Abstract: To provide a small motor-operated valve which can control a high flow, there is provided a motor-operated valve of which a body has an orifice, seat and a valve element provided opposite to the seat. The valve element is operated by a driver which is driven to rotate by an output gear to which the rotation of a rotor having been reduced by means of a mechanical paradox planetary gear mechanism is transmitted. To force the valve element in the direction in which the valve is opened, a coil spring is disposed in a bore formed in the upper portion of the body oppositely to a bush.

Abstract: In an electromagnetic linear valve, a resilient member urges a plunger in a direction in which the core-opposing portions move away from a core portion, and moves the plunger in a direction in which the core-opposing portions approach the core portion where an electric current is supplied to a coil. Where no electric current is supplied to the coil, an axially opposing surface area as a surface area of portions of the core-opposing portions which respectively oppose inner peripheral surfaces of recessed portions is smaller than a radially opposing surface area as a surface area of portions of the core-opposing portions which respectively oppose bottom surfaces of the recessed portions, and the axially opposing surface area becomes larger than the radially opposing surface area where an electric current is supplied to the coil and the core-opposing portions approach most to the core portion.

Abstract: A control assembly for converting a “fail-close” regulator to a “fail-open” regulator, or vice versa, without having to modify or reconfigure a casing of the regulator includes a control member, a central rod, and a spring disposed between first and second spring seats. A regulator including the control assembly includes a valve body and an actuator casing, the valve body defining a fluid flow-path. The control member is slidably disposed within the actuator casing and adapted for displacement relative to the valve body for controlling the flow of fluid through the flow-path. The spring and spring seats are disposed about the central rod, such that the spring biases the control member into a predetermined position relative to the regulator casing.

Abstract: In a magnet system for MRI imaging comprising a superconducting magnet mounted within a cryogen vessel, apparatus is provided for controlling egress of cryogen gas from the cryogen vessel. The apparatus comprises a controlled valve linking the interior of the cryogen vessel to a gas exit path; and a controller arranged to control the valve. The valve is arranged such that a gas pressure in the cryogen vessel exceeding a gas pressure in the gas exit path acts on the valve to open the valve and allow venting of cryogen gas. The valve is also arranged such that a gas pressure in the cryogen vessel inferior to a gas pressure in the gas exit path acts on the valve to urge it closed, so restricting flow of gas into the cryogen vessel.

Abstract: A low torque operator for selectively engaging a gear unit in an actuating drive stem of a valve having a collar with an axial bore and a slot through its side. The slot includes a projection directed towards an upper end of the collar and has an edge oriented oblique to the collar axis. A drive shaft inserts in the bore, and a pin mounted in the drive shaft engages the slot during low torque conditions. The operator also includes an idler gear and a bullgear. A driven shaft with two drive pins inserts into the bore on a lower side of the collar. The upper of the two pins remains in contact with a shoulder formed on a lower end of the collar during low torque conditions. The lower of the two pins engages a shoulder formed on a lower side of the bullgear during high torque conditions.

Abstract: A method is disclosed for controlling a valve having a spring with a spring force, an actuator with an actuator force opposing the spring force, and a pin that is actuated by the actuator, a seal element that can be coupled with the pin, and a seal seat, the valve being closed when the seal element sits against the seal seat. The method includes determining an expected natural opening time when the seal element is lifted off the seal seat based on a pressure difference in front and behind the valve, impressing a specified current on the actuator at a point in time within a specified interval prior to the natural opening time, the seal element sitting against the seal seat at the point in time such that the pin contacts the seal element and the actuator force matches the spring force, which is reduced by a specified value.

Abstract: Plungers and plunger assemblies for a diaphragm-sealed valve are provided. Each plunger is adapted to be received in a passage of the valve body and includes a base member and an upper member having a longitudinal play in this passage with respect to the base member. A resilient middle element is provided between the upper and base member. The base member is connected to a plunger actuating mechanism within the valve body. Optionally, the upper member may be self-aligning within the passage. The plunger can be used to compensate for temperature variations experienced by the valve in use.

Abstract: A damping valve arrangement for a vibration damper includes a damping valve body, which has at least one through-flow opening for the damping medium, and at least one valve disk which at least partly covers the through-flow openings under the influence of a closing force. The damping valve arrangement includes at least one spring element which has at least one supporting portion axially supported at another structural component part of the damping valve arrangement, and at least one spring portion disposed at a distance from the supporting portion and which introduces a spring force into the valve disk at least indirectly, wherein the spring force of the spring element is directed counter to the closing force acting on the valve disk, and wherein the spring force of the spring element is less than the closing force of the valve disk.

Abstract: Provided is a configuration in which: a spool driven by an electromagnetic proportional solenoid is urged by a spool-returning spring configured to exert urging force in an opposite direction to a driving direction of the electromagnetic proportional solenoid; a mechanical stopper is disposed at the stroke end of the spool; current dither causes a control current to micro-vibrate, the control current driving the electromagnetic proportional solenoid; and the mechanical stopper includes a stopper-urging spring configured to allow the spool to vibrate owing to the current dither even when the spool is in contact with the mechanical stopper. A proportional solenoid control valve with this configuration is capable of reducing hysteresis at the stroke end of the spool by means of the current dither, and controlling the spool in a stable manner over the entire control range including the stroke end of the spool.

Abstract: A smart drain valve comprises a support plate, a bolt passing through a center of the support plate, an outer plate connected to a first end of the bolt, an inner plate connected to a second end of the bolt, and a spring positioned between the inner plate and the support plate. The spring is made of a shape memory material.

Abstract: The invention relates to a pressure regulator (1) in a shock absorber valve. The pressure regulator (1) comprises an axially movable first valve part (4) and a first seat (3), which are arranged in a valve housing (2) in such a way that an adjustable flow opening is created between the parts (3, 4). The flow opening is arranged to restrict a damping medium flow (q) and its flow opening size (s) is determined by a force balance on the first valve part (4). The force balance is principally or partially created by the sum of an actuating force (F) and the force (Fs) from a spring arrangement counter to the action of a counter holding regulator force (R). The spring arrangement comprises a first spring (5) having a first spring constant (k1) and a second spring (6) having a second spring constant (k2).

Abstract: The invention relates to a valve module for influencing a fluid supply of a fluid-operated load, comprising a valve housing (4) which defines a valve chamber (17) with a fluidically communicating connection to an inlet port (18) and an outlet port (19), and further comprising a valve member (5) which is movably accommodated in the valve chamber (17) and which is adjustable along a movement axis (21) between a blocking position and a release position in order to influence a free flow cross-section between the inlet port (18) and the outlet port (19), and further comprising a spring mechanism (20) designed to apply a presettable preloading force to the valve member (5) in order to determine a preferred position of the valve member (5) in the valve chamber (17), characterised in that the spring mechanism (20) is supported, with an end region thereof which is remote from the valve member (5), on a supporting means (45) which can be located, within an adjustment range, in a freely selectable adjustment position re

Abstract: A valve assembly for use in a fuel pump comprises a body member with a valve aperture, a valve member movable within the body member and adapted to close the valve aperture, and a biasing arrangement having a first part fixed with respect to one of the body member and the valve member and a second part fixed with respect to the other of the body member and the valve member. The biasing arrangement is adapted to bias the valve member to close the valve aperture. The biasing arrangement comprises a helical spring with a first diameter at the first part and a second diameter at the second part. The first diameter of the helical spring is different from the second diameter of the spring. The helical spring is at its first part retained by an interference fit against the member with respect to which it is fixed.

Abstract: An electro-valve for discharging a common rail while maintaining a minimum pressure, comprising an electro-magnetic coil inside which is arranged a movable plunger, controlling the displacements of a movable axis engaging a ball valve, said movable plunger being urged in the closing position of the ball valve by a spring housed inside a bearing cap, wherein a bottom wall of the bearing cap surrounds an external surface of the movable plunger, wherein a clearance between the external surface of the plunger and an internal wall of the bearing cap is filled with a film of fuel, the opening movement of the plunger causing the fuel to flow from a room situated on top of the plunger to a bore in which the axis is arranged, wherein a sleeve of a controlled thickness is arranged around the plunger within the clearance to set the thickness of said film of fuel.

Abstract: A gas oven having a gas supplying passage to supply gas to a burner is provided. The gas oven includes an ON/OFF valve to open/close the gas supplying passage, and a flow rate modulating valve connected to the ON/OFF valve in series so as to change the cross-sectional area of a passage, thereby supplying a proper amount of gas to a cooking cavity in response to the change of a cooking area. When a cooking cavity is divided into individual cooking cavities while a divider is mounted, the flow rate modulating valve is open/closed at a smaller opening degree than the maximum operating degree, and thus may be able to prevent a cooking substance from being carbonized in the individual cooking cavities.

Abstract: A control assembly for a fluid flow control device includes a control element, a load spring, and a spring clip. The control element can be movably disposed for controlling fluid flow, and the load spring biases the control element into a predetermined position. The spring clip contacts the load spring at a plurality of points to dampen vibrations experienced by the load spring, thereby reducing and./or eliminating resonance. The spring clip includes a body plate and first and second opposing arm plates extending away from the body plate. Each arm plate includes a proximal end adjacent the body plate, a distal end spaced away from the body plate, and a finger extending upwardly away from the distal end. A corner at an intersection between the finger and the distal end includes a contoured edge for facilitating attachment of the load spring to the spring clip.

Abstract: A spring retaining sleeve includes a cylinder press-fit connection surface which has a press-fit diameter and a press-fit length. To enable cost-effective production of a stable press-fit assembly, at least one end of the cylinder press-fit connection surface, an optimized insertion chamfer for long press-fit assemblies is provided with a ratio of press-fit diameter to press-fit length of greater than thirty five percent.

Abstract: A pressure-actuated valve fit to a tubing string for alternately closing to communicate fluids from a wellbore to the tubing string and opening to communicate fluids from a wellbore annulus to the tubing string. The valve is particularly useful for lifting liquids which accumulate in the tubing string when the reservoir has a diminished pressure. In this case, gas is accumulated in the wellbore annulus and when the valve is opened the gas enters the valve and is directed to the tubing string for lifting the liquids. The valve is closed by a spring and has a closing-assist which applies an additional force to the spring to ensure the valve is fully closed.

Abstract: An electromagnetic pressure-regulating valve includes a housing comprising a first, a second and a third port, a valve seat, a valve closure member, an electromagnetic drive, and a biasing device. The electromagnetic drive comprises a coil wound on a coil carrier, an armature, a core, and an electromagnetic return-path device. The armature moves between a first and second end position and acts on the valve closure member. The biasing device is configured so that, when a current does not flow, the armature, and thereby the valve closure member, is positioned in a fail-safe setting on the valve seat so that a connection from the third port to each of the first and second ports is closed. The valve seat is connected via a fluid channel to the first and second ports. The armature is steplessly adjustable between the first and second end positions in every setting.

Abstract: A seat block capable of maintaining a well-fitted state of a seat portion in a simple and reliable manner regardless of use conditions. A seat portion base body (43) is provided in a housing (67) provided with a valve passage (66) and allows a piston (28) for opening and closing a valve passage (66) to be pressed on the seat portion base body (43). A spring member (23) applies an elastic force to the seat portion base body (43) such that the elastic mechanism (23) cooperates with the housing (67) to retain the seat portion base body (43).