Abstract: A servovalve has a sleeve having both a first metering aperture and a second metering aperture in fluid communication with a single port cavity defined by the servovalve. A spool oriented within the sleeve has a first land and a second land and defines a channel oriented between the first land and the second land. When the spool orients in a null position within the sleeve, the first land overlaps the first metering aperture and the second land overlaps the second metering aperture. As a low viscosity fluid within the servovalve assembly leaks across the first land and enters the channel, the overlap of the first and second lands with the first and second metering apertures minimizes flow of the fluid from the channel into the port cavity associated with the metering apertures. The configuration of the sleeve assembly, therefore, maintains a relatively large pressure gain within the servovalve assembly.

Abstract: A proportional solenoid valve or a camshaft adjusting device of motor vehicles has a valve housing and a piston movably arranged in the valve housing and provided with at least one pressure medium passage. A solenoid part is connected to the valve housing and acts on the piston. The valve housing has at least one working connector, a tank connector, and a pressure connector configured to supply a pressure medium into the piston. A leakage passage is provided that connects the pressure connector at all times to the at least one working connector.

Abstract: A seal having a body and several bands extending away from the body. The bands extend around an axial portion of the body. In some embodiments, the bands project from and are formed integral with the body. For example, the bands can be rings. Two bands can be located on the outside of the body and two additional bands can be located on the inside of the body to provide redundant sealing components between separated fluids. A vent aperture can be positioned between the two bands on each side of the body. The two inner bands can be offset from the two outer bands. The seal can be used in a surgical cutting device, among other things.

Abstract: A directional control valve for a hydraulic load has, in a piston bore of a valve housing, a control piston which can be displaced axially in opposite directions from a central position and which has first fine control grooves for opening a connection between a load chamber and a feed chamber. There are second fine control grooves for opening a connection between a load chamber and a discharge chamber of the piston bore under control. In its central position, there is a restricted relief connection from a load chamber to the discharge chamber via the control piston. The restricted relief connection is obtained via a recess in the control piston, independently of the second fine control grooves.

Abstract: A body element for a spool valve is provided that includes a body having an inner surface that defines an internal valving chamber having a longitudinal axis, and at least one transverse surface to the longitudinal axis. The transverse surface has at least one port comprising an annular flow passage, an intermediate flow passage and an outer flow passage extending outward from and in fluid communication with the inner surface of the internal valving chamber.

Abstract: A spool valve arrangement with a cylinder is fitted with a clearance fit in a cylinder bore in a housing of the spool valve arrangement. The housing has first pressure medium ports and the cylinder has second pressure medium ports. A socket is inserted through each first pressure medium port in the housing and each second pressure medium port in the cylinder. The socket has a small diameter part, which is fitted with a clearance fit in the second pressure medium port, and a large diameter part, which is engaged with a shoulder formed in the first pressure medium port. By screwing a conduit end in the first pressure medium port, the socket is held in the mounted position, thus providing a seal of the region of this port and also providing an anti-rotation effect on the cylinder relative to the housing.

Abstract: A slide spool valve has a valve body formed by synthetic resin injection molding. The valve body includes a bore and an insert integrally coupled with the bore. The insert has a hollow portion penetrated by a port, the hollow portion being connected to the bore and having the same diameter as the bore and penetrated by one of ports. A valve room having a large diameter extends from an inner circumferential surface of the hollow portion to the penetrating portion of the port. The insert is manufactured by die casting and fixed in a metallic pattern of the valve body, so that it is integrally coupled with the valve body by insertion molding.

Abstract: Disclosed is a flow force compensating spool valve having a flow force compensating protrusion ring at a supply channel of a sleeve on an outer circumference portion of a spool rod, and a hydraulic valve, a pneumatic valve, a three-way valve, and a four-way valve using the spool valve, in which the flow force can be compensated by a simple structure change of the spool without changing a structure of the sleeve.

Abstract: A pneumatic gate valve includes a valve housing made of injection-molded plastic material and having a plurality of external ports. Received in the valve housing are a plurality of valve bushings disposed in axial-spaced relationship as to define a valve bore and a plurality of pressure fluid compartments in fluid communication with the ports. A slide member for regulating a flow of compressed air between the ports is accommodated in the valve bore of the valve housing and displaceable in axial direction. The valve bushings are made of plastic material with a same melting temperature as the plastic material of the valve housing so as to realize a material union between the valve bushings and the valve housing, when plastic material is molded around the valve bushings during injection molding of the valve housing.

Abstract: An electromagnetic hydraulic valve (1), which including an electromagnet (2) with an armature (3) and of a valve housing (4) with an axial bore (5) and a piston valve (6) located therein is provided. The valve housing (4) includes several annular grooves (8, 9, 10) in which several radial openings (11, 12, 13) are located, which open into the axial bore (5), through which the hydraulic valve (1) has a fluid connection with a pressure connection (P), a tank connection (T) and two consumer connections (A, B). The piston valve (6) is acted upon by the armature (3) of electromagnet (2) and includes two ring-shaped control sections (14, 15), which connect alternatively the pressure connection (P) and the tank connection (T) with one of the consumer connections (A, B) through axial movement of piston valve (6). According to the invention, the radial openings (11, 12, 13) in valve housing (4) are provided as windows having a rectangular cross section.

Abstract: A spool-type hydraulic directional control valve having improvements to reduce cavitation when the spool is in the float position. The flow area of a first passageway on the valve spool is appropriately sized to reduce the flow hydraulic fluid flow from the head end of the hydraulic cylinder to the hydraulic fluid reservoir, such that a sufficient proportion of that hydraulic fluid instead flows internally through control valve and back to the rod end of the hydraulic cylinder to reduce cavitation when the valve spool is in the “float” position. Additionally, a second passageway on the valve spool may be blocked-off, eliminating the hydraulic fluid flow path from the hydraulic fluid reservoir to the rod end of the hydraulic cylinder when the valve spool is in the “float” position.

Abstract: The invention concerns a control device for adjusting the relative angular position of a driven shaft, particularly a camshaft of an internal combustion engine, said device comprising a drive pinion that is rotatably connected to the shaft, an adjusting element (1) for the angular adjustment of the drive pinion relative to the shaft, two chambers (2, 3) that are alternately supplied with hydraulic fluid and a control valve (6) for actuating the adjusting element (1), said control valve being connected to the chambers (2, 3) of the adjusting element (1) through pressure medium channels (4, 5). The control valve (6) comprises a valve body (7) that has two working connections A and B for the pressure medium channels (4, 5), a delivery connection P for the supply of hydraulic fluid and a discharge connection T for the discharge of hydraulic fluid, and the control valve (6) further comprises a sliding valve control piston (8) for setting different hydraulic resistances W between the individual connections.

Abstract: The invention concerns a control device for adjusting the relative angular position of a driven shaft, particularly a camshaft of an internal combustion engine, said device comprising a drive pinion that is rotatably connected to the shaft, an adjusting element (1) for the angular adjustment of the drive pinion relative to the shaft, two chambers (2, 3) that are alternately supplied with hydraulic fluid and a control valve (6) for actuating the adjusting element (1), said control valve being connected to the chambers (2, 3) of the adjusting element (1) through pressure medium channels (4, 5). The control valve (6) comprises a valve body (7) that has two working connections A and B for the pressure medium channels (4, 5), a delivery connection P for the supply of hydraulic fluid and a discharge connection T for the discharge of hydraulic fluid, and the control valve (6) further comprises a sliding valve control piston (8) for setting different hydraulic resistances W between the individual connections.

Abstract: A pneumatic valve group (10) with eased installation and maintenance, comprising in a single body (12) at least one through-duct (16) for supplying compressed air and at least one discharge duct (17) both connected to at least two further through-ducts (14), with a circular section and arranged transversally to such a through-duct (16) for supplying compressed air and at least one discharge duct (17); in at least one of these further ducts (14) spools (22) and relative ferrules or cartridges (18) are inserted, wherein the spools are able to be displaced axially to realise a desired valve function connected to the outside of the body (12) by means of usable passages (32).

Abstract: A manual control mechanism for a lift unit having a lift arm and a hydraulic cylinder for lifting the lift arm up and down. The mechanism includes a control valve configured as a three-position switchover valve for selectively providing lowering, neutral and elevating conditions according to a spool position for controlling movement of the hydraulic cylinder, a lift lever for manually operating the control valve and an operational path for guiding operational displacement of the lift lever. The operational path includes an inching operational path for operating the hydraulic cylinder at a creeping speed by slightly opening a port of the control valve and a main operational path for operating the control valve over an entire stroke range thereof. An operational feel when the lift lever is operationally displaced along the inching operational path is different from an operational feel when the lift lever is operationally displaced along the main operational path.

Abstract: What is disclosed is a method for manufacturing a valve piston, as well as a valve piston, wherein flow in the fine control range is determined through control windows formed by a through opening extending through the valve body.

Abstract: A pneumatic slide valve includes a valve housing made of injection-molded plastic material and having a valve bore and a plurality of external ports. The valve housing has an outer housing portion, made of reinforced plastic and determinative for a geometric outer dimension of the valve housing, and an inner housing portion made of non-reinforced plastic and extending continuously in the valve housing. The inner housing portion defines several pressure fluid compartments in fluid communication with the ports and the valve bore at least in a region which is positioned in the area of the pressure fluid compartments, wherein the outer housing portion is molded around the inner housing portion. A slide member is accommodated in the valve bore of the valve housing for displacement in the direction of the axis, for regulating a flow of compressed air between the ports.

Abstract: A bushing for a hydraulic valve has a bushing wall having openings allowing passage of a hydraulic medium to and from an interior of the bushing. The openings have an opening wall that at least across a portion of a circumference of the opening wall is formed as a molded bevel. The molded bevel is positioned at an acute angle to a radial plane of the bushing wall. The bushing wall has outer annular channels and the openings open into the outer annular channels, respectively.

Abstract: The invention concerns a control device for adjusting the relative angular position of a driven shaft, particularly a camshaft of an internal combustion engine, said device comprising a drive pinion that is rotatably connected to the shaft, an adjusting element (1) for the angular adjustment of the drive pinion relative to the shaft, two chambers (2, 3) that are alternately supplied with hydraulic fluid and a control valve (6) for actuating the adjusting element (1), said control valve being connected to the chambers (2, 3) of the adjusting element (1) through pressure medium channels (4, 5). The control valve (6) comprises a valve body (7) that has two working connections A and B for the pressure medium channels (4, 5), a delivery connection P for the supply of hydraulic fluid and a discharge connection T for the discharge of hydraulic fluid, and the control valve (6) further comprises a sliding valve control piston (8) for setting different hydraulic resistances W between the individual connections.

Abstract: The invention concerns a control device for adjusting the relative angular position of a driven shaft, particularly a camshaft of an internal combustion engine, said device comprising a drive pinion that is rotatably connected to the shaft, an adjusting element (1) for the angular adjustment of the drive pinion relative to the shaft, two chambers (2, 3) that are alternately supplied with hydraulic fluid and a control valve (6) for actuating the adjusting element (1), said control valve being connected to the chambers (2, 3) of the adjusting element (1) through pressure medium channels (4, 5). The control valve (6) comprises a valve body (7) that has two working connections A and B for the pressure medium channels (4, 5), a delivery connection P for the supply of hydraulic fluid and a discharge connection T for the discharge of hydraulic fluid, and the control valve (6) further comprises a sliding valve control piston (8) for setting different hydraulic resistances W between the individual connections.

Abstract: A valve has a solenoid part and a valve part connected to the solenoid part. The valve part has a housing provided with connecting bores for a pressure medium, including a pressure connector and working connectors. The valve part has a piston and the solenoid part acts on the piston to alternatingly connect the working connectors to the pressure connector. The valve part has at least one groove extending alongside the valve part. At least one of the connecting bores is positioned in the at least one groove.

Abstract: A spool valve comprises a slidable spool, and through displacement of the spool a supply port of the valve is allowed to communicate with one of the load ports of the valve while the other load port is allowed to communicate with a corresponding one of return ports of the valve. The spool is provided with a portion, the outside diameter of which gradually increases, at least on the other load port side from the center of a central concave portion of the spool. The outside diameter gradually increasing portion decreases fluid force which acts against an operating force of the spool when the valve is activated.

Abstract: A nozzle needle of a fuel injector is driven in a controlled manner by changing back pressure applied thereto. The back pressure is controlled by a pressure control valve driven by stacked piezoelectric elements. A valve body of the pressure control valve is disposed in a valve chamber having a drain port and a high pressure port which are selectively closed. A diameter D1 of a drain seat, a diameter D2 of a high pressure seat, and a diameter D3 of a piston portion connected to the valve body are set to satisfy a relation: D1≧D2≧D3. In this manner, operation of the pressure control valve is stabilized, and thereby the fuel injector is smoothly and stably operated.

Abstract: An improved pressure regulator suitable for use with paint ball guns comprises a hollow valve body, a valve mechanism for selectively releasing gas from a gas source to an output, and an ON-OFF control. The valve body has a coupling portion, a regulator seat, an output port, an inlet opening, and sidewalls defining a transverse spool socket. The valve mechanism includes a regulator seat, a valve plug movable within a plug chamber for sealing engagement with a regulator seat, and a fluid barrier axially movable with respect to the valve body. A spool is received in the socket and movable between a first position wherein an internal passage is defined between the gas inlet opening and the regulator seat, and a second position wherein the flow of gas from the gas inlet is blocked.

Abstract: A shuttle valve assembly, comprising a valve housing containing first, second and third ports, and a cavity in the housing, a poppet shiftable in the cavity between a first position and a second position, the poppet in its first position directing flow between the first port and the second port, communication between the second port and third port then being blocked, the poppet in its second position directing flow between the third port and the second port, communication between the second port and first port then being blocked, and a friction responsive holder acting to hold the poppet in its first position until fluid pressure shifts the poppet to its second position, and to hold the poppet in its second position until fluid pressure shifts the poppet to its first position.

Abstract: A hydraulic valve assembly for selectably delivering hydraulic fluid from a supply of hydraulic fluid to one of a first hydraulic operator and a second hydraulic operator is disclosed. The assembly includes first and second supply ports which communicate with the supply and four operator ports. First and third ports communicate with the first hydraulic operator. Second and fourth ports communicate with the fourth hydraulic operator. First and second chambers are provided. The first chamber communicates with the first supply port and first and second operator ports. The second chamber communicates with the second supply port and third and fourth operator ports. Two selection valves operating in unison are each located in each chamber. The selection valves operate between a first position at a first hydraulic fluid pressure and a second position at a second hydraulic fluid pressure.

Abstract: A proportional solenoid valve or a camshaft adjusting device of motor vehicles has a valve housing and a piston movably arranged in the valve housing and provided with at least one pressure medium passage. A solenoid part is connected to the valve housing and acts on the piston. The valve housing has at least one working connector, a tank connector, and a pressure connector configured to supply a pressure medium into the piston. A leakage passage is provided that connects the pressure connector at all times to the at least one working connector.

Abstract: A spool valve includes a sleeve and a spool. The sleeve has a first communicating hole opening into the cylinder bore and a second communicating hole opening into the cylinder bore and separated from the first communicating hole in the axial direction of the cylinder bore. The spool is fluidtightly accommodated in the cylinder bore to slide and has one end portion which opens and closes the first communicating hole upon sliding operation thereof and the another end portion which opens and closes the second communicating hole upon sliding operation thereof. At least one of the end portions has an end surface extending from the outer circumference approximately at a right angle to the spool axis and an inclined surface which progressively decreases a diameter of the spool from the end surface.

Abstract: A fluid system for supplying low and high pressure fluid is provided. A first pump discharges a first pump flow. A filter receives a first portion of the first pump flow and discharges a filter flow. A first accumulator receives a first portion of the filter flow. A valve receives a second portion of the first pump flow and a second portion of the filter flow, and discharges a valve flow. The valve is movable between a first position, providing a first flow path between the second portion of the first pump flow and the valve flow, and a second position, providing a second flow path between the second portion of the filter flow and the valve flow. A second pump receives the valve flow and discharges a second pump flow. A second accumulator receives the second pump flow.

Abstract: A stepped down groove 53 is provided around the peripheral surface of a rod portion 43 of a spool 40 which faces a third oil groove 33. Both the axial ends 53a and 53b of the stepped down groove 53 are located axially outside of both the axial ends 33a and 33b of the third oil groove 33 at least while the valve is in pressure-adjusting condition. Also, another stepped down groove 52 is provided around a land 42 which faces a first oil groove 31. Both the axial ends 52a and 52b of the stepped down groove 52 come, respectively, to the right and left sides of the axial end 31b of the first oil groove 31 to which end the spool 40 shifts to increase the opening of the oil groove at least while the valve is in pressure-adjusting condition.

Abstract: The invention is based on a directional control valve which is used for the control, in particular the load-independent control, of a hydraulic load in terms of direction and speed. A known directional control valve of this kind has, in a piston bore of a valve housing, a control piston which can be displaced axially in opposite directions from a central position and which has first fine control grooves for opening a connection between a load chamber and a feed chamber under control, and second fine control grooves for opening a connection between a load chamber and a discharge chamber of the piston bore under control. In its central position, there is a restricted relief connection from a load chamber to the discharge chamber via the control piston. The restricted relief connection is obtained in the known directional control valve by the second fine control grooves being lengthened to such an extent that they already project into the load chambers in the rest position of the control piston.

Abstract: The invention concerns a control device for adjusting the relative angular position of a driven shaft, particularly a camshaft of an internal combustion engine, said device comprising a drive pinion that is rotatably connected to the shaft, an adjusting element (1) for the angular adjustment of the drive pinion relative to the shaft, two chambers (2, 3) that are alternately supplied with hydraulic fluid and a control valve (6) for actuating the adjusting element (1), said control valve being connected to the chambers (2, 3) of the adjusting element (1) through pressure medium channels (4, 5). The control valve (6) comprises a valve body (7) that has two working connections A and B for the pressure medium channels (4, 5), a delivery connection P for the supply of hydraulic fluid and a discharge connection T for the discharge of hydraulic fluid, and the control valve (6) further comprises a sliding valve control piston (8) for setting different hydraulic resistances W between the individual connections.

Abstract: A solenoid control valve for use in actuation of a manual hydraulic clutch in a vehicle. The solenoid control valve has an electronically operated solenoid with armature and actuator rod displaced through a channel in the solenoid. A spool valve has a valve body that is coupled at one end to the solenoid. A spool is slidably disposed in the control channel. A first and second dampener chambers are located at the two ends of the spool. The dampeners function to improve the stability in the control system and balance the transient flow forces of the hydraulic fluid as it moves through the valve member. The spool also has a control portion is located between the first end and the second end of the spool. The control portion allows the control portion to communicate with a supply, control and exhaust passages in the valve body.

Abstract: A pressure control apparatus which controls a pressure of air supplied from a supply hole of a base having a plurality of holes to a supply port of a valve having a plurality of ports is interposed between the base and the valve. This pressure control apparatus comprises a pressure control section which controls a pressure of the air such that the pressure becomes equal to a set pressure, a booster section which outputs a large amount of air to the valve by controlling an output pressure by air from this pressure control section, and a signal control section which outputs a monitor signal indicative of completion of pressure setting when the pressure of air output from the booster section becomes equal to the set pressure.

Abstract: Disclosed is a flow force compensating spool valve having a flow force compensating protrusion ring at a supply channel of a sleeve on an outer circumference portion of a spool rod, and a hydraulic valve, a pneumatic valve, a three-way valve, and a four-way valve using the spool valve, in which the flow force can be compensated by a simple structure change of the spool without changing a structure of the sleeve.

Abstract: A system and method serve for optimizing the efficiency of an oil supply having at least two different oil pressure levels. The system has at least two feed devices and at least one control slide with at least two narrowed sections. Each of the narrowed sections is assigned one of the feed devices. Depending on the position of the narrowed sections in the control slide, the respective volume flows are automatically divided into the at least two pressure levels for each of the feed devices as a function of the oil requirement in the respective pressure level.

Abstract: A spool valve comprises a valve body formed with a slide hole therein, a spool slidably received in the slide hole, a supply port, two load ports and two return ports, all of which ports are formed in the slide hole. The load and return ports are disposed with the supply port being the center. The spool has a central concave portion and two land portions, and with the displacement of the spool, the supply port is allowed to communicate with one of the load ports while the other land port is allowed to communicate with a corresponding one of the return ports. The spool is provided with a portion, the outside diameter of which gradually increases, at least on the other load port side from the center of the central concave portion. The outside diameter gradually increasing portion is formed in a conical shape, a curved drum shape, a stepped columnar shape or the like.

Abstract: A pneumatic slide valve includes a valve housing made of injection-molded plastic material and having a valve bore and a plurality of external ports. The valve housing has an outer housing portion, made of reinforced plastic and determinative for a geometric outer dimension of the valve housing, and an inner housing portion made of non-reinforced plastic and extending continuously in the valve housing. The inner housing portion defines several pressure fluid compartments in fluid communication with the ports and the valve bore at least in a region which is positioned in the area of the pressure fluid compartments, wherein the outer housing portion is molded around the inner housing portion. A slide member is accommodated in the valve bore of the valve housing for displacement in the direction of the axis, for regulating a flow of compressed air between the ports.

Abstract: In a fuel injection system for internal combustion engines, including an electronically triggered control valve with an axial through bore, which is divided by two valve seats into three annular chambers, to which respectively a supply line for fuel at high pressure, a high-pressure line leading away to an injection valve, and a relief line are connected, and having a control piston, which is guided in the through bore and which has two valve sealing faces cooperating with the two valve seats, respectively, the control piston according to the invention has a further valve sealing face, which cooperates with the first valve seat and whose spacing from the first valve sealing face is at least equal to the spacing between the second valve sealing face and the second valve seat when the first sealing seat is closed. A communication between the supply line and the relief line is thus reliably prevented.

Abstract: A reverse boost valve assembly for installation within the hydraulic pump of an automatic transmission is disclosed. The present invention includes valve pistons that oscillate within close-tolerance mating valve sleeves to minimize hydraulic leakage. The present valve pistons are manufactured from aluminum material and are provided with a hard anodize coating, which produces a low coefficient of friction between the mating surfaces. The valve sleeves are provided with a compatible anodize coating or, in the alternative, are fabricated from highly wear-resistant aluminum material. The reverse boost valve assembly is provided in both standard volume and oversize embodiments, which are interchangeable to permit a predetermined rate of line pressure rise to be selected for a given transmission. The reverse boost valve assembly is also supplied with or without external O-ring seals, which function to prevent line pressure leakage at the interface of the valve sleeve and the hydraulic pump body.

Abstract: A spool valve includes a groove defined in the spool and a notch. A line A is drawn to extend through a communication zone a provided upon communication of the notch which is disposed at a distal end of the line A and defined in a step of a spool with an input port to form a 69° angle with respect to an L-axis. Fluid flowing into the groove through the communication zone a upon communication of the notch with the input port, does not collide with other portions of the spool before colliding with a bottom of the groove. Therefore, the flow of the fluid along the L-axis causes a flow force applied to the spool to be suppressed resulting in a decreased load on an actuator. The notch makes it is possible to ensure the stable operation of a spool valve, while preventing the self-induced vibration of the spool.

Abstract: In a magnetic driving device, a fixed core has a housing portion, in which a plunger is housed to reciprocatingly move, and an attracting portion toward which the plunger is attracted upon energizing a coil. The housing portion is provided with a ring portion, which is formed by machining an outer circumference wall thereof and whose thickness is thinner than that of a part of the housing portion adjacent to the ring portion to an extent that mechanical strength of the housing portion is not damaged. The ring portion is provided with a plurality of through-holes penetrating radially the wall thereof. A magnetic flux area of the ring portion is limited due to the thin wall and the through-holes so that magnetic resistance is enlarged.

Abstract: An electromagnetic valve comprises a case having a cylindrical portion, a yoke having a large diameter portion and a small diameter portion, and a sleeve having at least two ports and receiving a valve member therein so as to perform reciprocating motion. The large diameter portion of the yoke is fluid-tightly pressed into the inner circumferential surface of the cylindrical portion of the case, and the inner circumferential surface of the sleeve is fluid-tightly pressed onto the outer circumferential surface of the small diameter portion of the yoke.

Abstract: A spool valve is provided which has a plurality of small-diameter portions formed at predetermined spacings on a peripheral surface of a shaft, and pairs of annular ridges on peripheral surfaces of the small-diameter portions to have a larger diameter than an inner diameter of collars. The collars are closely fitted between the annular ridges to make valve bodies, and the collars include an inner wall, an outer wall and at least one connection therebetween, and an annular gap is provided between the inner wall and the outer wall.

Abstract: A spool valve which can set the relative location between the spool and the sleeve adequately and easily and which can ensure the smooth flow of the fluid includes a sleeve and a spool. The sleeve has a first communicating hole which is opened into the cylinder bore and a second communicating hole which is opened into the cylinder bore and which is separated from the first communicating hole with a predetermined distance in the axial direction of the cylinder bore. The spool is fluidtightly accommodated in the cylinder bore to slide and has one end portion which opens and closes the first communicating hole in response to the sliding operation thereof and the other end portion which opens and closes the second communicating hole is response to the sliding operation thereof.

Abstract: A manual valve of a hydraulic pressure control system for an automatic transmission of a vehicle according to the present invention comprises a valve body provided with a line pressure receiving port, a P/N range port for supplying hydraulic pressure in more than one range of parking range P and neutral range N, a plurality of hydraulic pressure supplying ports and a plurality of exhaust ports; and a valve spool slidably inserted into the valve body and having a plurality of valve lands, a first valve land of said plurality of valve lands having a exhaust groove depressed toward a neighboring land, wherein: each width of the line pressure receiving port and the P/N range port is smaller than each diameter of said plurality of valve lands, whereby a tight seal is maintained when each of the line pressure receiving port and the P/N range port is blocked by said plurality of valve lands; and each width of the plurality of hydraulic pressure supplying ports is greater than each diameter of said plurality of valv

Abstract: A hydraulic control device for a transmission of a motor vehicle has a housing with a bore hole and a valve piston that is contained in the bore hole and slidable between different axial positions. The shift levels of the transmission are determined by setting the axial position of the valve piston. Prior to installation of the control device on another part of the motor vehicle, the valve piston is secured by a safety element against axial movement. Installation of the control device causes the safety element to release the valve piston.

Abstract: An electromagnetic valve is constructed such that lengths of sealing portions, formed by a housing 8 and a spool valve 7 respectively between an input port 8a and a feed-back chamber 11 and between the feed-back chamber 11 and a core 4, are unchanged upon movement of the spool valve; and aligning grooves 15a and 15b are respectively formed between the input port 8a and the feed-back chamber 11 and between the feed-back chamber 11 and the core 4, whereby a smooth and stable pressure is constantly obtainable in response to an applied current even though a supplied pressure is high.

Abstract: A spool valve includes a pressure control portion and a pair of flow control portions. Each flow control portion is adjacent to, and on opposite sides of, the pressure control portion. A first plurality of opposed notches are formed in the pressure control portion. The first plurality of notches have a first geometry. A second plurality of opposed notches are formed in each flow control portion. The second plurality of notches include at least one notch of a second geometry, different from the first geometry, and at least one notch of a third geometry, different from the first and second geometries.

Abstract: A hydraulic neutral cold start control valve for a variable displacement hydraulic unit includes a housing with a spool bore and an intersecting signal pressure passage therein. A spool is disposed in the bore and is mechanically biased to a closed or neutral position of the valve by a pair of opposing springs. A plunger is associated with one of the springs and has a surface that usually sealingly contacts one end of the spool but extends radially therebeyond such that it is in fluid communication with the signal pressure passage. When the signal pressure exceeds a threshold value, the pressure forces the plunger to separate from the end of the spool. Then the movement of the spool becomes proportional to the signal pressure, which is desirable for normal operation and control of the hydraulic unit.