Abstract: A hydraulic pressure transformer for the conversion of an input hydraulic power to an output hydraulic power has a cam block. The cam block has a cam opening defining a pump section and a motor section. The pump section includes at least one pump inlet port and at least one pump outlet port. The motor section includes at least one motor inlet port and at least one motor outlet port. A rotor is disposed within the cam opening and is rotatable about an axis of rotation. The rotor includes a peripheral surface, a plurality of radially extending slots opening at the peripheral surface and a plurality of vanes respectively disposed in the slots. The rotor and/or cam block are movable relative to each other in at least one direction generally perpendicular to the axis of rotation.

Abstract: First and second fluid pressure chambers are formed in both sides of a movement direction of a cam ring swingably placed within a pump body. A spool of a control valve is moved due to a pressure difference between the front and back of a metering orifice. Fluid pressures of the fluid pressure chambers are controlled. The cam ring is swung. Further, a solenoid for giving thrust in an axial direction thereof to the spool of the control valve and electronic control device for controlling driving of the solenoid are provided. The electronic control device has a steering sensor and determines a steering direction based on a signal from the steering sensor and also calculates a steering speed to the steering direction and controls a driving current of the solenoid in response to this steering speed and changes a discharge flow rate of a pump.

Abstract: A variable displacement pump (28) having a combination inlet port (71) and an outlet (76) formed integrally on the rear body (32). By integrating the combination inlet port (71) and outlet (76) on the rear body (32), this invention simplifies the manufacture of the pump (28) as compared with known variable displacement pumps.

Abstract: A regulatable pump, in particular a vane pump, is provided with a rotor, with a rotor body and with at least one guide ring and with a cam ring. The eccentricity of the cam ring can be adjusted by means of a regulating piston, a journal of the cam ring lying between a spring-pretensioning means and the regulating piston. At maximum eccentricity, the cam ring bears on the outside by means of a bearing part of its circumferential wall against a bearing surface on the inside of the housing.

Abstract: A variable displacement vane-type fluid pump is provided which permits improved regulation of the pump discharge such that the pump can meet the various requirements of lubrication for internal combustion engines at all speeds with minimized use of power. Of course, the vane pump may also be utilized in a wide range of power transmission and other fluid distribution applications. The variable displacement vane pump of the invention may utilize both hydrostatic and mechanical assistance in radially positioning its vanes to ensure efficient and quiet operation of the pump and to facilitate priming of the pump. The vane pump of the invention may also use both hydrostatic and mechanical actuators to control the position of its containment ring or eccentric ring and hence, regulate the output of the pump.

Abstract: A cam ring 10 is slidably supported within a pump body 2, and a rotor 20 is rotatably disposed inside the cam ring. The cam ring is eccentric to a rotation shaft 22 of the rotor. The rotor carries a plurality of vanes 18 that can be advanced or retreated, in which a pump chamber 24 is formed in a space between the cam ring and the rotor. The cam ring is formed with the first and second fluid pressure chambers 14 and 16 on both sides thereof, and biased in a direction where the displacement of the pump chamber is at maximum by a spring 26. A control valve 28 is provided in which a differential pressure across a metering orifice is applied on both ends of a spool 32 and a spring 36 is disposed on the side of an end face where a downstream fluid pressure is applied. The fluid pressures of the fluid pressure chambers 14 and 16 are controlled by means of the control valve, whereby the cam ring is swung.

Abstract: In a variable displacement pump for a power steering device of a vehicle, the adapter ring is arranged to be easily engaged with the engagement hole at the pump casing, to improve ease of assembly. The relationship of the adapter ring with the engagement hole reduces vibration and noise.

Abstract: A variable displacement vane pump includes a pump housing having a cylindrical interior chamber, a cylindrical rotor member mounted for rotational movement within the interior chamber of the pump housing, a cam member mounted for pivotal movement within the interior chamber of the pump housing about a fulcrum aligned with the vertical centerline of the interior chamber, the cam member defining a cam body having a circular bore extending therethrough for receiving the rotor member, the cam body having lateral sealing lands formed thereon, the sealing lands having arcuate sealing surfaces defining segments of a cam arc through which the cam member pivots, and static cam seals supported within the interior chamber of the pump housing and oriented on each end of a chord of the cam arc, each cam seal biased into a continuous contact position with an adjacent sealing surface of the cam member.

Abstract: A vane pump is disclosed for use with gas turbine engines which has pressurized fluid supplied to the undervane portion of the vane elements to balance the forces imparted thereon. The vane pump includes a pump housing, a cam member, a cylindrical rotor member and a chamber. The chamber is defined within the housing and positioned for fluid communication with the undervane portion of each vane element to provide a desired pressure thereto. The chamber is in fluid communication with a first pressure source and a second pressure source, wherein the first pressure source is associated with the discharge arc segment of the pumping cavity, and the second pressure source is associated with the inlet arc segment of the pumping cavity.

Abstract: First and second fluid pressure chambers 43 and 44 are formed on both sides of a swingable cam ring 27. A control valve 40 for controlling a swing of the cam ring is provided. To operate the control valve, a variable metering throttle 61 is provided in the middle of a discharge path. The variable metering throttle 61 is formed with a communicating channel 62 which is formed in the side surface of one side of the cam ring in the axial direction, and communicates with a discharge-side hollow 33 being formed in a pressure plate 30 which faces the side surface, and a small hole 63 which is bored in the pressure plate 30 while facing a part of the communicating channel, and of which the opening area is varied with the side edge 62a of the communicating channel of the cam ring 27 when the cam ring swings.

Abstract: A fuel metering unit including a pump having a rotor with a plurality of slots. The pump also includes a pivotally movable cam ring coaxially arranged with respect to the rotor. Vanes are slideably disposed in the slots for maintaining contact with the cam ring during movement thereof. A servovalve has a motor and nozzles operatively connected to the pump such that increased flow through the first nozzle pivots the ring of the pump toward maximum while increased flow through the second nozzle pivots the ring toward minimum. An arm extends between the nozzles for varying fluid flow therethrough. The arm couples to the motor such that the motor moves the arm. A flow meter connects to the pump and an end of the arm for applying a force against the arm to assist in maintaining position of the arm.

Abstract: A flow control valve has body (20) containing a “bucket” shaped valve element (1) that moves in a bore (2). The valve element (1) has a discharge orifice (8) through which a needle valve (9) projects. Movement of the valve element (1) within the bore (2) adjusts the annular clearance between the orifice (8) and the needle (9) thereby varying the pressure drop across the valve element (1) and the rate of the main flow through the valve. The inlet (4a) to the body (20) is located upstream of the valve element. With this arrangement, the spill flow rate is adjusted by movement of the valve element (1) within the bore (2). However, in all cases the main flow of fluid passes through the orifice (8) of the valve element (1) through the bore (2) to the outlet (10), thereby avoiding the formation of stagnant “pools” of fluid within the bore (2) of the flow control valve.

Abstract: A pump chamber 18 is formed between a cam ring 17 and a rotor 15 in a pump body 11. The cam ring is formed so as to move to direction that pump capacity of the pump chamber increases and decreases. A first and second fluid pressure chambers 33 and 34 are formed at both sides of moving direction of the cam ring 17. The pump has a spool operates to axis direction by difference in fluid pressure of upper and lower stream sides of a metering throttle 50 formed on a way of a discharge side passage 27 of the pump chamber and provides at least a control valve 30 controlling fluid pressure in the first fluid pressure chamber. An electronic driving unit applying thrust to axis direction to the spool of the control valve, for example, a solenoid 60 is provided.

Abstract: A regulatable pump, in particular a vane pump, is provided with a rotor, with a rotor body and with at least one guide ring and with a cam ring. The eccentricity of the cam ring can be adjusted by means of a regulating piston, a journal of the cam ring lying between a spring-pretensioning means and the regulating piston. At maximum eccentricity, the cam ring bears on the outside by means of a bearing part of its circumferential wall against a bearing surface on the inside of the housing.

Abstract: In a variable displacement pump, a relief valve is constituted by a pilot drive type relief valve obtained by adding a pilot valve to a main valve, a fluid pressure in a downstream side of a metering orifice provided in a pump discharge side passage is applied to the pilot valve, and the main valve is capable of opening and closing a downstream side passage of the metering orifice with respect to a drain passage.

Abstract: A cam case 23 is provided which swingably supports a cam ring 34 fitted to a rotor 33 having a vane 33a to form a pump chamber 36 from the outer surface such that the cam ring 34 is swingably supported by a swingable pin 35 disposed in the axial direction as a fulcrum, the cam case 23 serving as an intermediate body. Pump bodies are disposed on the two ends of the cam case in the axial direction. Moreover, a front body 21 and a rear body 22 for rotatively supporting a rotational shaft 40 of the rotor are disposed. A low-pressure chamber 80 for introducing low-level hydraulic pressure is formed at a position between the backside of the pressure plate and the front body, the position opposing a suction-side region 36A of the pump chamber.

Abstract: A variable displacement vane pump is disclosed which includes a pump housing having a cylindrical interior chamber, a cylindrical rotor member mounted for rotational movement within the interior chamber of the pump housing, a cam member mounted for pivotal movement within the interior chamber of the pump housing about a fulcrum aligned with the vertical centerline of the interior chamber, the cam member defining a cam body having a circular bore extending therethrough for receiving the rotor member, the cam body having lateral sealing lands formed thereon, the sealing lands having arcuate sealing surfaces defining segments of a cam arc through which the cam member pivots, and static cam seals supported within the interior chamber of the pump housing and oriented on each end of a chord of the cam arc, each cam seal biased into a continuous contact position with an adjacent sealing surface of the cam member.

Abstract: A variable displacement pump includes pump bodies, a cam ring, first and second fluid pressure chambers, a rotor, a driving shaft, a pump chamber, a compression coil spring, a metering restrictor portion, and a control valve. A plunger damper is formed to incorporate the compression coil spring such that a distal end of the plunger damper abuts against a side portion of the cam ring in the second fluid pressure chamber. A small hole constituting the metering restrictor portion is formed at such a position that it is opened/closed by a slidable motion of the plunger damper during a swing motion of the cam ring, and such that it is partitioned from the second fluid pressure chamber, so that an opening area of the small hole changes in an interlocking manner to the swing motion of the cam ring.

Abstract: A pump for supplying fluid, in particular hydraulic oil, comprises a drive shaft extending into the interior of the pump housing and the shaft is mounted on at least one bearing device lubricated by a partial flow of the fluid supplied. A sealing device seals the radial gap between the housing of the pump and the drive shaft. The sealing device comprises a sealing ring of substantially U-shape cross-section. One arm of the U forms a first sealing portion resting against the drive shaft under pre-stress. The other arm of the U forms a second sealing portion resting under pre-stress against a sealing face of the housing surrounding the drive shaft. The sealing ring has a sealing area connecting the first and second sealing portions and forming the base of the U and facing the interior of the pump so that the first and second sealing portions extend from the sealing area in a direction away from the interior of the pump.

Abstract: In a variable displacement pump, a pump body has an inner surface and is formed with suction and discharge paths communicating with the inner surface. First and second fluid pressure chambers are divisionally formed between the inner surface of the pump body and an outer surface of a cam ring through a seal portion including a swing fulcrum pin. A spring biases the cam ring from the second fluid pressure chamber toward the first fluid pressure chamber. A metering restrictor is provided between the discharge paths. A control valve is connected to the discharge paths formed upstream and downstream, respectively, of the metering restrictor and to the first and second fluid pressure chambers, and is driven by fluid pressures present upstream and downstream of the metering restrictor.

Abstract: A variable displacement pump has a swingable, displaceable cam ring fitted to form a pump chamber together with the outer circumferential surface of a rotor having vanes. Notches are formed by notching to have a substantially V-letter shape in the starting end portions, in the rotating direction of the rotor, of a pump suction opening and pump discharge opening that open to the pump chamber. The notch formed in the starting end portion, in the rotor rotating direction, of the pump suction opening is constituted by a plurality of notched grooves aligned in the radial direction of the pump chamber and having different lengths in the rotating direction of the rotor. Hence, the timing at which the pump suction opening communicates with a pressure chamber formed between the vanes changes in accordance with swing and displacement of the cam ring.

Abstract: A scroll-type machine is disclosed which is particularly well suited for use as a compressor in refrigeration and air conditioning systems and incorporates a unique arrangement for modulating the capacity thereof. In one group of embodiments the capacity of the scroll-type machine is modulated by relative axial movement between the scroll members so as to form a leakage path across the wrap tips and opposed end plates. In another group of embodiments, modulation is achieved by reducing the orbital radius of one of the scroll members to thereby form a leakage path across the flank surfaces of the wraps. In the second group, a plurality of pin members are moveable from a first and second positions. In a first position the plurality of pin members operably enable the scroll members to orbit and in a second position the pin members restrict the orbiting motion of the first scroll members.

Abstract: A cam case 23 is provided which swingably supports a cam ring 34 for forming a pump chamber 36 from a rotor in a state in which the rotor 33 having a vane 33a is moved to an eccentric position such that a swingable pin 35 axially disposed is used as a fulcrum. A pump body is formed adjacent to the two axial ends of the cam case. Moreover, a front body 21 and a rear body 22 for rotatively supporting a rotational shaft 40 of the rotor are disposed. As one of locating means for locating the two bodies and the cam case when an assembling process is performed, the swingable pin is employed. As another locating means, at least one of joining means for integrally connecting the two bodies and the cam case is a reamer bolt 45A.

Abstract: A variable displacement vane pump comprising a durable rotor member having journal ends at each side of a larger diameter central vane section comprising vane slots having well areas which slidably-engage a mating vane element. The present vane pump comprises an outer cylindrical cam enclosure or spacer loaded against ring seal elements to support the faces of the seal elements closely spaced from the cam faces and reduce the actuation force required for adjustment of the displacement capacity of the pump. The cam faces include a biased segment seal in the high pressure discharge arc area. The seal elements include first fuel inlet passages in the inlet arc segment thereof, and fuel discharge passages in the discharge arc segment thereof, both of said passages being open to the vane slot extensions and to the cam chamber for the continuous supply and pressure discharge of fuel.

Abstract: A pump comprising a pump housing (12) and a rotor (28) driven by a shaft (10), said rotor having at least two outwardly spring-biased elements (30). These lie in contact with the wall of a chamber (27) surrounding the rotor and transport, during rotation of the rotor, a gas and fluid medium from a suction port (15) to a pressure port (16) in the housing. The chamber (27) is arranged in a sliding block (18) which is displaceable inside the housing (12) in such a way that the chamber is movable between two end positions, of which one end position is concentric with, or presents a comparatively small eccentricity with respect to, the rotating shaft (10) of the rotor and which second end position presents a comparatively large eccentricity with respect to said shaft.

Abstract: A scroll-type machine is disclosed which is particularly well suited for use as a compressor in refrigeration and air conditioning systems and incorporates a unique arrangement for modulating the capacity thereof. In one group of embodiments the capacity of the scroll-type machine is modulated by relative axial movement between the scroll members so as to form a leakage path across the wrap tips and opposed end plates. In another group of embodiments, modulation is achieved by reducing the orbital radius of one of the scroll members to thereby form a leakage path across the flank surfaces of the wraps. Both types of scroll separation may be accomplished in a time pulsed manner to thereby enable a full range of modulation with the duration of the loading and unloading periods being selected to maximize the efficiency of the overall system.

Abstract: To restrain the swinging of a movable displaceable cam ring and a spool of a control valve and to suppress pulsation on the discharge side of a variable displacement pump. In the variable displacement pump, a variable metering orifice (40) is provided midway in discharge-side passages (24, 29, 43, 44, 45) extending from a pump chamber. A spool-type control valve (30) is operated with the fluid pressure on the upstream and downstream sides of the orifice to control the fluid pressure supplied to fluid-pressure chambers around the cam ring in accordance with the flow rate of the fluid discharged from the pump chamber. A single or multistage throttle portion including throttles (50, 51, 52) is provided in at least one of fluid passages (46, 47) for communicating the upstream side of the orifice to one chamber of the valve, and fluid passages (35, 19b) for communicating the one chamber to the first fluid-pressure chamber as the valve operates.

Abstract: A variable capacity or displacement type pump by which a pump discharge quantity is variably controlled in accordance with the revolution number, which has simple construction to contributes easier machining and assembling, and is reliable in operation. A cam ring is movably arranged to define a pump chamber around a rotatable rotor within a pump body and is biased so that the volume of the pump chamber is made maximum. Sealing members are provided in an annular space between the cam ring and the pump body so as to define first and second hydraulic pressure chambers through which the cam ring is driven to move. A switch valve is provided to control the hydraulic pressure transmitted to the first and second chambers in accordance with the quantity of the flow discharged from the pump chamber.

Abstract: A vane pump has a casing, a controlling collar guided leaktightly in the casing and movable relative to a rotor mounted in the casing and surrounded by the controlling collar. The movement of the collar is transverse to the axial direction of the rotor. A suction region of the pump is defined by a volume increasing in the direction of rotation of the rotor, of a vane cell formed between two adjacent vanes and decreasing to the pressure region. At least one adjustment member is provided to adjust the position of the controlling collar in dependence on the prevailing pumping parameters. In order to provide a vane pump of space-saving and/or simple and cost-saving design, at least one recess is open towards the outside of the controlling collar and is provided on the controlling collar close to the pressure region to accommodate and adjustment member.

Abstract: A radial piston hydrostatic machine contained within a housing and comprising a cylinder-barrel mounted to rotate on a pintle-valve fixed to said housing. Two hydraulic-rams operatively acting on a track-ring to provide eccentric displacement relative to the pintle-valve to change the rate of fluid output from the machine. The hydraulic-rams being of unequal size and subjected to the same level of machine discharge pressure during periods when the level of discharge pressure is insufficient to cause an internally disposed pressure relief-valve to "open". A throttle-valve disposed in a fluid channel linking the cylinders of said hydraulic-rams and arranged to introduce a pressure differential across two said two cylinders during periods when the machine discharge pressure is sufficiently high to cause said pressure-relief-valve to "open".

Abstract: Methods and devices for enhancing bootstrap hydraulic systems for use in vehicular power steering systems are disclosed. Improved pressure dividing networks are provided for enabling balanced operation of supply pressure control function when valve input shaft and sleeve are in relative centered positions or for enabling a first method of providing speed sensitive control of steering assist. Control valves utilizing a combination of open-center and closed-center flow control orifices are provided for reducing parasitic pressure losses. An improved variable displacement pump is provided for enabling volumetric flow rate efficient operation of bootstrap systems. A vehicular speed dependent command signal for a servo motor powered bootstrap hydraulic system is utilized in another method of providing speed sensitive control of steering assist.

Abstract: A hydraulic apparatus for a construction machine, which is adapted to prevent the number of revolutions of an engine from increasing when the flow of the fluid discharged by a variable displacement hydraulic pump driven by the engine is cut off. The hydraulic apparatus comprises a proportional solenoid (11) connected to a fuel supply control lever (13) so as to vary the horsepower characteristics of the engine, which are set by the action of a governor (12) based on manipulated variable of the fuel supply control lever (13) when the flow of the fluid discharged by said pump is cut off, and a controller (10) for controlling the proportional solenoid (11). In this apparatus, a decrement (.DELTA.Nr) in a target number of revolutions per minute (Nr) of the engine, which can be obtained by subtracting a target number of revolutions per minute (Nrb) of the engine at the desired engine horsepower characteristics (l.sub.

Abstract: A hydraulic circuit comprising a control pump having first and second adjustment means for changing the output volume of fluid pump, and a regulating valve adapted to suppy user means with a pressurized liquid.

Abstract: A control valve for a variable displacement pump is improved so that the levelling of the pressure fluctuations of the pump is better and quicker. For this purpose an additional control piston portion on the control piston of the control valve is used. Corresponding to the deflection of the control piston the constriction cross-section set by the control piston portion between the supply connected to the pump pressure line and a passage leading to the control space of the variable pump is varied so that the pressure rise in the control space of the pump and also the pressure drop is accelerated.

Abstract: The invention relates to a hydraulic vane type pump and to a radial piston pump. The cam ring of said pumps is adapted for horizontal and vertical movement. So as to achieve stable operating conditions for the pump at least within a certain range, a single-piece support body is mounted within the vertical adjustment screw so as to avoid a change in the level of height when the cam ring is moved axially.

Abstract: The invention relates to a vane pump having input and output slot means. Either the input slot means or the output slot means are designed such that for a movement of the cam ring into a position of zero excentricity the area of overlap between the input slot means and the output slot means is increased.

Abstract: An automatic transmission, for a vehicle with an engine, includes a hydraulic fluid pump which supplies pressurized hydraulic fluid. The engine load is detected, and the pump output is controlled so as to increase with increase of the load on the engine. If the pump is one whose output per one revolution of its input member is variable, then its output may be thus controlled by increasing its output per one revolution along with increase in engine load. And, if the pump is a variable capacity type vane type hydraulic fluid pump the output of which per one revolution of its input member is controlled by varying the eccentric position of a controlling member thereof, then its output per one revolution may be thus controlled by detecting the eccentric position of the controlling member using a sensor, and by varying this eccentric position in a feedback manner to achieve a target eccentric position which is determined to give a pump output per one revolution varying as an increasing function of engine load.

Abstract: An adjusting arrangement for a vane or radial piston pump in which the forces applied outwardly to the cam ring are compensated by the application of hydraulic pressure to each of a plurality of sections about the ring. System pressure is applied to one section and a regulating pressure to another. A spring or hydraulic arrangement absorb any force differential.

Abstract: A control valve for a variable displacement pump is improved so that the levelling of the pressure fluctuations of the pump is better and quicker. For this purpose an additional control piston portion on the control piston of the control valve is used. Corresponding to the deflection of the control piston the constriction cross-section set by the control piston portion between the supply connected to the pump pressure line and a passage leading to the control space of the variable pump is varied so that the pressure rise in the control space of the pump and also the pressure drop is accelerated.

Abstract: In order to stabilize the line pressure developed by a line pressure regulator valve and simultaneously control the operation of a variable capacity pump in a manner that the latter exhibits the desired degree of response to changes in the line pressure, a flow restriction is defined in the bore of the valve itself. This flow restriction is defined between the wall of the bore in which the spool is disposed and a portion of the spool which extends between two adjacent lands and which has a diameter which is slightly smaller than that of the bore.

Abstract: The radial plunger pump has a rotor in which a plurality of plungers are radially slidingly received and have their outer ends in engagement with a guide ring which is provided so as to be eccentric from the rotor, so that the plungers reciprocate in their cylinders as the rotor rotates. The eccentric amount is controlled by the movement of a controlling piston, and the movement of the controlling piston is controlled by a pilot valve. The pilot valve which has a sleeve and a shaft member, switches the pressure in a chamber formed behind the controlling piston in order to control the movement of the controlling piston. The position of the shaft member of the pilot valve is further controlled by an electrical control, so that the critical point at which the pilot valve switches the pressure is controlled by the electrical control.

Abstract: A reversible flow vane pump having a pump case with a pump chamber in which a rotor is mounted. The rotor has outwardly-opening slots which carry vanes which engage a cam ring and with fluid chambers between vanes. The cam ring can be adjusted to positions at either side of a neutral position to provide reversible flow operation between a pair of ports, with variable volume control. The ports are arranged to increase the length of time in which a port communicates with an intervane fluid chamber which is of decreasing volume for increased utilization of fluid being pressurized. A port which functions as an inlet port in a predominant mode of operation of the pump has an extension effective to increase the length of time in which an intervane fluid chamber of increasing volume can be filled with fluid.

Abstract: A pump has a stator formed with intake and output ports connected to the lubricating system of an internal-combustion engine of an automotive vehicle for flow therethrough, a rotor in the stator positively driven by the engine output, an adjustment element operatively connected to the stator and rotor and displaceable between one end position corresponding to relatively great flow through the pump when the rotor is rotated by the output and an opposite end position corresponding to substantially no flow through the pump when the rotor is rotated by the engine output, and a biasing unit for urging the adjustment element toward the one end position with a fixed force. An abutment unit is connected to the adjustment element of the pump for limiting displacement of same from an intermediate position between its end positions into the opposite end position corresponding to no flow through the pump.

Abstract: A variable output vane pump for use with an automotive automatic transmission. At least one pressure chamber is formed between the circular bore of a housing and the outer circumference of a ring by means of at least one seal pin which is fitted in the axial groove formed in the ring circumference and which is opened in the housing bore. The ring is urged by the action of a spring, which is fitted in the housing, in a direction opposite to the pressure to be built up by the pressure chamber. An elastic member is fitted in the bottom of the axial groove to urge the seal pin both toward the housing bore and at the same time toward one of the side walls of the axial groove. The urging direction of the elastic member and a tangential line, on which the seal pin is tangential to the housing bore, are angularly positioned at an acute angle with respect to each other.

Abstract: There is provided a control device for a vane type variable displacement pump. The control device eliminates the need of a hydraulic cylinder to control the eccentricity of a cam ring of the vane pump. A pressure difference between a second chamber and a high pressure side of the pump first chamber on a low-pressure side of the vane pump is utilized to determine the eccentricity of the cam ring. A regulator valve is connected to the first chamber and with the second chamber in order to allow or prevent communication between the two chambers. A spring is also provided to always force the cam ring in a direction so as to make the eccentricity of the cam ring larger.

Abstract: A variable displacement rotary piston pump has a rotor splined to a driven shaft, a plurality of radially directed cylinders, each having a slidable piston fitted therein, a pumping ring surrounding the rotor and mounted eccentrically of the axis of the rotor with which the pistons maintain contact and are caused to move within the cylinders, a piston return ring engageable with notches formed on the pistons and an eccentric mounted for rotation to which the pumping ring is secured having an actuator pin whose movement determines the position of the pumping ring with respect to the rotor, thereby regulating the flow rate of the pump. The pump destrokes above the idle speed of the engine from which it is driven and limits the flow rate of the pump. A venturi orifice establishes a differential pressure which is applied across a flow control valve, which directs hydraulic fluid at discharge pressure to one or the other of two control pistons thereby adjusting the eccentric position.

Abstract: A precise pressure regulator includes a housing defining a bore having pressure and relief zones, a pressure port communicating with the pressure zone, a relief port communicating with the relief zone, and a control port. A follower is slidable and a spool is rotatable in the bore. The spool defines a first passage for communicating the pressure zone with the control port and a second passage for communicating the control port with the relief zone. A spring biases the follower in one direction tending to block the first passage. Pressure in the pressure zone biases the follower in the opposite direction tending to block the second passage. A step motor rotates the spool in discrete steps to precisely control its position, which position determines the level at which pressure is regulated.

Abstract: A power regulating device for a hydrostatic pump with at least one pressure-loaded piston which adjusts a stroke-varying member and is controlled by a valve with two springs acting upon one side of the valve and a gauge piston loaded by the delivery pressure and a lever through which a force proportional to the delivery pressure acts upon the other side of the valve, is provided with an additional spring which acts upon the gauge piston via an intermediate member in the same direction in which the delivery pressure acts, and with a second pressure medium source arranged to act with a variable control pressure upon the intermediate member against the additional spring.

Abstract: A vane type pump with a variable capacity for power steering devices is provided with a movable ring received and radially movable in a closed cylindrical bore of a pump housing. A spring acts on the movable ring to deflect the axis of the movable ring from the axis of a rotor, which is rotated to move vanes along an internal bore of the movable ring. A sealing pin and a valve element are provided at diametrically opposite sides of the movable ring and define first and second pressure chambers around the movable ring. The first pressure chamber receives pressurized fluid from a part of the internal bore of the movable ring and conducts the pressurized fluid into the second pressure chamber through a throttle, which is defined by the valve element and a part of a circumferential external surface of the movable ring. The throttle generates a pressure difference between the first and second pressure chambers, and the pressure difference acts on the movable ring to move the same against the force of the spring.

Abstract: A control system for maintaining the product of the lifting pressure and lifting volume times flow constant in an adjustable pump having a regulating member acted upon by two pressure-controlled pistons. The device includes a control valve which is operatively connected with a spring with a linear characteristic, which spring is through the control valve operatively connected to an adjusting lever having an arm which is varied proportionally to the working pressure of the pump. The moment is produced by the force of that spring and that variable lever arm. A counter moment is generated by a force of a second spring and a second arm of the adjusting lever. Upon creating the force equilibrium on the adjusting lever the control valve is so controlled that the product of the pumping pressure and pumping volume times flow remains constant. The control valve controls one of the two pressure-controlled pistons which adjusts the stroke of the regulating member.