Abstract: A high pressure pump includes a housing with a chamber formed inside and a flow control valve and a discharge check valve installed in the chamber; a piston installed to operate up and down in an assembly hall formed in the housing to compress fuel in the chamber to a high pressure; a cylinder forming a gap between an inner circumferential surface and the piston and guiding reciprocation of the piston; and a support member seated on a stepped surface of the housing to surround an outside of the cylinder and configured to elastically support the housing and the cylinder, thereby reducing friction while preventing fuel leakage between the piston and the cylinder.

Abstract: A shaft connection 1 for a longitudinal shaft assembly, has at least a first shaft having a first and second ends, and a second shaft, disposed so as to be coaxial with the first shaft, having first and second ends; the shafts extending axially. The first end forms a hollow portion. The first shaft end forms a first journal having a displacement portion. The first shaft end at least in an initial position of the shaft connection extends through the hollow portion which axially by the displacement portion forms a guide portion and circumferentially forms a form-fitting first connection. In the initial position a mutual axial displacement of the first and second shafts is prevented by an axial securing feature. In a crash the axial securing feature; is releasable by an axial release force. The first shaft is axially displaceable relative to the second shaft.

Abstract: A metering device for dispensing a predetermined amount of lubricant includes a lubricant reservoir, which retains a lubricant and dispenses it under pressure via an outlet of the lubricant reservoir, and a metering apparatus, which comprises at least one microvalve. The microvalve is fluidly coupled with the outlet of the lubricant reservoir and dispenses the predetermined amount of lubricant in a defined manner. The metering apparatus is spatially separable from the lubricant reservoir.

Abstract: A compressor includes a housing; a compressor liner positioned within the housing and at least partially defining a first cylinder with an inlet and an outlet; a piston positioned within the first cylinder and configured to compress air flowing into the first cylinder through the inlet; a cylinder head at least partially defining the first cylinder; and a sealing assembly for sealing an interface between the compressor liner and the cylinder head. The sealing assembly includes a ring seal at an interface between the cylinder head and the compressor liner; a vent port on an opposite side of the ring seal from the first cylinder; and a vent tube extending between the vent port and the inlet such that air leaking through the ring seal from the first cylinder flows through the vent port, through the vent tube, and into the inlet.

Abstract: Described are embodiments of a pump having a diagnostic port that enables users and support personnel to diagnose the source of a pump leak. The diagnostic port is monitored visually or with a pressure or liquid detection sensor. In some embodiments, fluid detected at the diagnostic port corresponds to a leak around a circumference defined at an outer sealing surface of a high pressure seal. In other embodiments, fluid detected at the diagnostic port corresponds to a leak around a plunger at the inside diameter of the high pressure seal. Multiple diagnostic ports can be provided to allow separate determinations of leaks about the different portions of the high pressure seal. The embodiments may eliminate the need to disassemble the pump to determine the source of leaks. Thus the effort required to diagnose and repair the pump can be substantially reduced, and fewer misdiagnosed components are ordered or replaced.

Abstract: A fuel pump for a direct injection system comprises at least one pumping chamber, a piston slidingly mounted inside the pumping chamber to cyclically vary volume thereof, an intake duct connected to the pumping chamber and regulated by an inlet valve, a delivery duct connected to the pumping chamber and regulated by a one-way valve that allows only outgoing-fuel flow from the pumping chamber, a seat arranged below the pumping chamber around a lower portion of the piston, an annular seal housed in the seat and preventing fuel leakage along a side wall of the piston, and an annular element that delimits, on an upper side thereof, the seat housing the seal such that an axial dimension of the seat is not greater than an axial dimension of the seal to prevent the seal from axially “shaking” inside the seat as a consequence of cyclic axial movement of the piston.

Abstract: A fuel gallery has a first opening port communicated to a variable volume chamber formed at a lower side of a plunger and a second opening port communicated to a fuel pressurizing chamber formed at an upper side of the plunger. A connecting tube member is provided in the fuel gallery for communicating the first and second opening ports with each other. During a fuel amount adjusting stroke, for example, in which the plunger is moved in an upward direction, a part of excessive fuel from the fuel pressurizing chamber is supplied to the variable volume chamber through the connecting tube member and the remaining part of the excessive fuel is discharged from the connecting tube member into the fuel gallery through a communication through-hole formed in the connecting tube member.

Abstract: A piston and a reciprocating expansion engine with a piston having a piston head, a piston neck, and a piston shaft are described. The piston head has at least one groove which runs in a circumferential direction suitable for receiving a piston ring, and the piston shaft has a pin boss and, at its outer circumference, a guide surface which is suitable for guiding the piston along a cylinder inner wall. An outer diameter of the piston neck is smaller than an outer diameter of the piston head and/or of the piston shaft, and the length of the piston neck approximately corresponds to the travel of the piston in the installed state.

Abstract: A control system for a reciprocating device which includes a switching valve for directing fluid supply under pressure to one of two drive lines in an alternating manner, means for alternating the switching valve, and an exhaust circuit including and exhaust outlet, a first flow restrictor disposed between one drive line and the exhaust outlet, and a second flow restrictor disposed between the other drive line and the exhaust outlet. The system may include a selection valve for alternately connecting one of two drivelines to the exhaust outlet.

Abstract: A sealing unit includes a mismatched metal-to-metal seal and an o-ring seal with a vent hole therebetween. The mismatched metal-to-metal seal may provide a sealing surface between two metals that may withstand high temperatures and pressure while avoiding leakage over many cycles. The sealing units of the present invention may provide a seal capable of withstanding pressures greater than about 5,000 psig, and typically greater than 6,000 psig, and more typically greater than 7,000 psig; and temperatures greater than about 300° F., and typically greater than about 400° F., and more typically greater than about 500° F. over a service life of more than 5,000 cycles. By providing a vent hole between the metal-to-metal seal and the o-ring seal, should either seal leak, damage to the other/good seal may be prevented by expelling the leak out of the system.

Abstract: An actuation system for a servo-assisted transmission; the actuation system is provided with: a hydraulic circuit comprising a reservoir containing a control fluid, a hydraulic accumulator containing the pressurized control fluid, and a pump which draws from the reservoir and feeds the hydraulic accumulator; at least a hydraulic actuator comprising at least one actuation chamber and a mobile piston which slides within the actuation chamber; a solenoid valve for connecting the actuation chamber of the hydraulic actuator to the hydraulic accumulator and to the reservoir; and a recirculation circuit, which departs from at least one environment bordering with the actuation chamber of the hydraulic actuator and ends in the reservoir.

Abstract: In an electrically-driven piston pump including a fluid reservoir for retaining fluid that has leaked into a cam chamber, at an edge between a side wall surface of the cam chamber and the fluid reservoir, an upper edge, which is positioned on the upper side, is arranged so as to extend downward from the electric motor side toward the side away from the electric motor. With this arrangement, the fluid that has leaked into the cam chamber from a piston bore flows from the electric motor side toward the side away from the electric motor, coursing along the upper edge due to the gravity, and is thus introduced into the fluid reservoir.

Abstract: A hydraulic linear actuating drive includes a cylinder, a movable servo piston that can be pressure-loaded and that runs inside the cylinder, at least one piston rod attached to the servo piston, and at least one piston gasket having at least two sealing elements at a distance from each other. An intermediate sealing space is defined between the at least two sealing elements, an inner wall of the cylinder and an outer edge of the servo piston. The hydraulic linear actuating drive has at least one leakage channel that can move together with the servo piston. A first end of the channel opens into the intermediate sealing space and into a leakage fluid inlet opening located there, while the other, second end of the channel opens into a leakage fluid outlet opening arranged outside of the cylinder.

Abstract: The invention relates to an apparatus and method of statically sealing a reciprocating-type fuel pump, such as a direct injection high pressure piston-type fuel pump. The first embodiment of the invention is a fuel pump comprising a pump body, a fuel reservoir within the pump body, wherein the fuel reservoir is capable of holding fuel and a bellows attached to the pump body, wherein the bellows is a stretchable membrane acting as a static seal. The second embodiment further comprises a diaphragm seal inside the pump body, and adjacent to the fuel reservoir, and a working fluid reservoir adjacent to the diaphragm seal, wherein the working fluid reservoir is capable of holding fluid. The diaphragm seal is a static seal separating the working fluid reservoir and the fuel reservoir.

Abstract: A diaphragm pump including, in a pump body, a hydraulic control chamber disposed between a piston for executing reciprocating motion and the diaphragm, the pump including elements for compensating leaks from the hydraulic chamber, the elements including a refilling duct opening out into the hydraulic chamber via a normally-closed compensation shutter that is driven into the open position by the diaphragm, wherein the above-mentioned compensation shutter being driven by the diaphragm pressing against a free end of a rod for controlling the shutter, the diaphragm being subjected to the force of a suction-assistance spring which co-operates with the above-mentioned shutter to return it to its closed position by pushing the free end of the control rod back towards the diaphragm, the spring co-operating with the shutter to form a moving assembly that is moved without being deformed by the diaphragm during suction overtravel.

Abstract: A hydraulic actuator has an armored section having concentric cylinders and an unarmored section having a cylinder with a frangible piston and a frangible upper gland nut. The hydraulic actuator may have leakage vents adapted to prevent leakage between hydraulic systems used to power the cylinders. The hydraulic actuator also may have a gland seal for sealing an end of the cylinder of the unarmored section and a sensing port adapted for allowing detection of fluid leaking due to damage of the gland seal.

Abstract: The problems can be solved by ensuring that Ga?Gb<Gc or Ga<Gb?Gc, wherein Ga denotes a clearing between the bore on the portion from the compression chamber of the high pressure pump to the cylindrical groove and the plunger, where a transverse aperture is connected with the bore through a cylindrical groove provided halfway through the bore of a cylinder; Gb a clearance closer to the cylindrical groove, out of the clearances between the bore from the cylindrical groove to the drive source side and the plunger; and Gc a clearance closer to the drive source side, out of the clearances between the bore from the cylindrical groove to the drive source side and the plunger.

Abstract: The invention demonstrates how energy saving working cylinders are loaded with fluid under pressure in order, for example, to power devices for tensioning (toggle joint tensioning apparatus), and/or compressing and/or jointing and/or stamping and/or embossing and/or punching and/or welding, if necessary, under the interposition of gearing parts such as guides, parallelogram gears, toggle joint articulations or the like, with the fluid supply being controlled in such a way during the no-load stroke (idle stroke) of the piston (4) that only the forces of inertia and/or weight and/or the forces of friction of moveable parts are overcome and pressure is not applied from the fluid until the power stroke of the piston (4).

Abstract: A reservoir chamber 33, which communicates with a vent passage 34 provided in an electric motor 11, is formed between a motor casing 20 of the electric motor 11 and a body 13 in which a drain port 59A, which communicates with the reservoir chamber 33, is provided with its external open end oriented downwardly, and a capacity of the reservoir chamber 33 below the vent passage 34 is set to become larger than a sum of a cooling contraction amount of air in the electric motor 11 and the reservoir chamber 33 which contracts in response to cooling by water covering the pump apparatus which has been warmed up under an operating environment and a pressurizing compression amount of air in the electric motor 11 and the reservoir chamber 33 which is compressed by a water pressure applied from the drain, port 59A when the pump apparatus is submerged.

Abstract: The invention concerns a fluid pump with a cylinder, piston and check valve for compressing the fluid having a high-pressure seal for precluding leakage of pressurized fluid. Any leakage from the high-pressure seal feeds back into an inlet area of the pump and recycles through the pump instead of leaking externally.

Abstract: A self-vacuum arrangement for pneumatic equipment is provided. A Venturi device having first and second ports and a central tap is provided. A first check valve having a first port operably coupled with the central tap of the Venturi device is configured to prevent pneumatic flow from the central tap through the first check valve. Optionally included is a second valve having a first port operably coupled with the first port of the Venturi device, and a second port operably coupled with the second port of the Venturi device.

Abstract: The present invention relates to a motor-pump unit for slip-controlled vehicle brake systems, including an accommodating member for hydraulically active elements comprising at least one working piston, which is arranged and guided in the accommodating member so as to be movable in a translational manner, and projects with an end into a crank space 6 for a rotationally movable driving element which is encompassed by a bearing having a bearing ring with an essentially bowl-shaped bottom, and extends over a frontal end of the driving element, and wherein the bottom is movable with an outside surface to rest against a crank space bottom. To improve friction and wear conditions, the crank space bottom includes an axial bearing element for the bottom which, starting from the accommodating member, projects in the direction of the bottom and has a contact surface with an area smaller than the area of the outside surface.

Abstract: The invention relates to a motor-pump unit for a motor vehicle brake system, comprising a motor and a pump which is provided with a shaft that is driven by said motor, with the shaft end being rotatably mounted by means of at least one bearing in an accommodating member having valves and connecting channels, said shaft driving displacement means which are disposed in a chamber that can be filled with pressure fluid. In order to improve vacuum filling of the brake system with pressure fluid, the invention discloses that the shaft end terminates into a free space, and that at least one connection is provided between the free space and the chamber.

Abstract: A device for a single-acting hydraulic cylinder (1) designed to lift or pull a load upon the existence of an oil pressure on the rod-side of a cylinder piston (7), where the cylinder bottom (15) of the hydraulic cylinder (1) is provided with a drainage outlet (27) for leakage fluid, as well as an air inlet (29).

Abstract: A hydraulic pump apparatus having an internal sump formed by a housing having an internal portion and an end cap secured to the housing. A rotatable cylinder block is located in the sump and driven by an input shaft extending into the housing. The pump apparatus also has a system of hydraulic porting in fluid communication with the cylinder block. The porting includes a pair of system ports located on a first side of the hydraulic pump apparatus, a fluid inlet on a second side of the hydraulic pump apparatus, opposite the first side, and a bypass valve positioned on the second side adjacent to the fluid inlet. A case drain may also be formed on a third side of the pump apparatus.

Abstract: A CO2 compressor for an air conditioner of a motor vehicle is suggested having a sealing device, assigned to the driveshaft of the CO2 compressor, which is implemented as a sliding ring. The CO2 compressor features a lubrication device, in which the sealing device is supplied a lubricant flow effected by centrifugal forces.

Abstract: In a variable displacement hydraulic pump having a housing with a multiplicity of interconnected surfaces, including opposed end surfaces and intermediate side surfaces, the improvement comprising the location of at least one case drain orifice in each of a plurality of differing ones of the surfaces in a manner such that at least one of the orifices is located in the vicinity of the top surface of the housing in any spatial orientation of the housing.

Abstract: A high pressure press for treatment of substances such as food includes a floating piston in a pressure chamber, with seals. The floating piston has drainage system for collecting any pressure fluid that leaks past a seal of the floating piston. The drainage system includes a pressure reducer arranged inside the floating piston. The drainage system also includes an elastometic pad which is so arranged as to supply an underpressure to a space where pressure fluid leaking past a seal may collect. Collected pressure fluid is returned to the pressure chamber later in the cycle.

Abstract: An elevator pit receptacle and float valve assembly provide for the safe displacement and collection of seeped hydraulic fluid from an elevator cylinder/piston assembly. The receptacle is elevated above the ground yet is below the cylinder seepage ring. A float valve is connected to the ring's drainage hole at one end, and a tube is connected therefrom to the receptacle. Should hydraulic fluid leak into the seepage ring, and the level of such fluid rises above the drainage hole, the fluid drains, by gravity, into the pit receptacle. In the event water intrudes into the elevator pit to a level that reaches the float, as the float rises, the valve shuts closed which prevents an unwanted commingling of water and drained fluid.

Abstract: A method, system and apparatus for performing peritoneal dialysis are provided. To this end, in part, a pump for a dialysis system is provided. The pump includes a first chamber wall including a first aperture, a second chamber wall including a second aperture, a piston, at least a portion of which can move through the second aperture, the piston including a third aperture, and first and second membranes disposed between the first and second chambers walls. A vacuum can be applied through the first aperture to pull the first membrane towards the first chamber wall and can be applied through the third aperture to pull the second membrane towards the piston. The piston can thereafter move the second membrane.

Abstract: A fluid cylinder with a swivel joint which is more improved with high utility is provided. To this end, in the fluid cylinder, a flow passage (R2b) leading to a chamber (1F) at the rod side of the cylinder is provided inside a rod (3), and a pin hole (3H) in a rod front end portion (3F) and a pin (P1) fitted in the pin hole (3H) are formed into a swivel joint so that the flow passage (R2b) is always guided to an outside even if the pin hole (3H) and the pin (P1) are relatively rotated.

Abstract: An expander that converts the thermal energy and the pressure energy of a working medium into mechanical energy includes, within a casing (12, 15, 18), an operating part such as a group of axial piston cylinders operated by the working medium introduced into an operating chamber, and a hermetically sealed lubrication chamber (102) in which oil for lubricating at least the operating part resides. Breather chambers (101, 103) are provided in an upper part of the lubrication chamber (102), and a working medium discharge chamber (90) into which the working medium is discharged from the operating chamber is made to communicate with the breather chambers (101, 103) via breather passages (B1 to B4).

Abstract: The invention relates to a method and apparatus for returning the oil drained from a working pressure space of a hydraulic motor into a motor casing to an oil line, which is connected to the motor and which is in communication via a divider with intra-motor flow channels which are in communication with the working pressure spaces. The oil seeping into the casing is conveyed by means of pressure variations internal of the hydraulic motor, pulsating consistently with rotating motion, into the oil line presently at a lower pressure and connected to the motor by way of said divider. Therefor, the casing space is connected by a return conduit through a one-way valve to at least one flow channel, which lies between the divider of the motor and the working pressure space of the motor.

Abstract: In a fuel path through which fuel is supplied to a pump-cam chamber accommodating a drive shaft and a cam for lubrication, an annular throttle fuel path is formed between an inside wall of a cylindrical body and an outside wall of a sphere, when the sphere is in contact with a seat provided inside the cylindrical body. The seat is provided with cuts through which the fuel flows when the sphere is in contact with the seat. Even if foreign material mixed in fuel once blocks a part of the annular throttled path, the blockage of the foreign material is released, when the fuel flow stops and the sphere leaves the seat, so that the fuel is always supplied sufficiently to the pump-cam chamber, resulting in preventing burn-in of the drive shaft and the cam, in particular, at a high engine revolution range.

Abstract: Guide for the piston rod of a piston-cylinder assembly, especially for a vibration damper, a shock-absorbing strut, or a level-control element, where the guide body holds the cylinder tube and the outside tube and simultaneously centers the piston rod in a central bore. The guide body has two axially spaced sealing elements which rest on the outside surface of the piston rod and seal off the interior space of the piston-cylinder assembly from the atmosphere. A flow connection, starting from the area of the intermediate space between the seals, extends to the interior space and is provided with a nonreturn valve, through which a flow can proceed only in the direction of the interior space.

Abstract: The pumping set comprises an electric motor (10), the output shaft (12) of which is drivingly connected to a piston pump arrangement (14) for delivering hydraulic fluid. To prevent hydraulic fluid, which escapes at the piston pump arrangement (14) during operation, from passing into the interior (39) of the electric motor (10), a collecting region (30) is provided, which is connected to a storage chamber (36) in order to receive hydraulic fluid therein.

Abstract: In the case of an intake noise muffler for a brake booster, a gas-permeable and noise muffling filter element, which is of plastic, is provided as the filter element for the intake air and extends along the entire length of the distributor housing or of a sleeve of a control valve housing.

Abstract: In diaphragm compressors diaphragm heads with oil spaces of high energy content (pressure×volume) have a strongly negative influence on the operating response of the oil overflow valve. The reaction of the valve leads to undesirably long open times causing more oil to flow out than brought in by an oil compensation pump, and causing many strokes to occur during which the diaphragm is no longer moved to its dead point. Accordingly not all compressed gas is pushed out of the compressor, which is connected with a rapid lowering of the suction efficiency. This problem is solved by the invention in that a throttle mechanism is arranged inside or outside of the oil space which lowers the oil pressure inside of the conductor to the oil overflow valve during the process in question and creates a constant differential pressure within the viscosity band of the oil.

Abstract: The invention depicts and describes a clamping device for securing a draw-in bolt (12) on a machine table, a baseplate, or the like, having a piston (6) that is arranged movably in a cylinder bore (4) to form a pressure chamber (5), a cover (9) that closes off the cylinder bore (4) on the side opposite the pressure chamber (5), a receptacle (11) which is configured in the piston (6) and/or the cover (9) and into which a draw-in bolt (12) can be inserted, and a clamping mechanism in order to secure a draw-in bolt (12) in the receptacle (11), the clamping mechanism being actuable by displacement of the piston (6) between a clamped position into which it is pushed by spring elements (10) that are arranged in a spring chamber (2) provided between the piston (6) and cover (9), and a released position into which it can be brought by impingement of a hydraulic medium on the pressure chamber (5), which is characterized in that the spring chamber (2) is connected to the receptacle (11) by at least one runoff duct (19)

Abstract: A symmetric pump having a symmetric end cap attached to a symmetric housing is disclosed. The end cap is attachable in a first position or a second position wherein the second position is rotated relative to the housing. A trunnion arm extends in a first direction and a system port opens in a first orientation when the housing is connected to the end cap in a first position, The end cap includes structure such that the housing may be connected in a second position so that the trunnion arm extends in a second direction while maintaining the system port opening in the first orientation. The end cap may be provided with a symmetric porting system. A control device for affecting movement of the swashplate is disclosed. Methods of locking the swashplate into a predetermined position are also taught.

Abstract: The invention relates to a hydraulic unit for a hydraulic control and/or regulating device, in particular for anti-blocking and/or anti-slipping brake systems, comprising control and regulating electronics arranged in a control housing as well as a valve block connected to said control housing, whereby at least one driving means is provided for at least one pressure-generating element. A cavity associated with the pressure-generating element receives leakage fluid from the pressure-generating element and a discharge channel that is connected to the cavity is provided in the valve block. According to the present invention, a means is associated with the discharge channel, and said means prevents fluid from entering into the discharge channel.

Abstract: A rotary vane pump for delivering a fluid, having a delivery device accommodated in a casing (2), a casing cover (3) arranged on one end face, and optionally with a bearing flange (4) adjoining the casing (2) on the side opposite to the casing cover (3). A seal (5,6) is arranged between the casing (2) and the casing cover (3) and optionally between the casing (2) and the bearing flange (4), and the seal (5,6) is inserted into a groove (8,9) formed in the casing cover (3), and optionally in the bearing flange (4), and/or in the respective end face (7) of casing (2). Also a leakage path (13) for the fluid extends between a delivery side (11) and suction side (12). The leakage path (13) extends on the inner side (14) of the seal at least in sections parallel to the seal (5,6).

Abstract: A pump assembly flows pressurized engine oil to HEUI fuel injectors in a diesel engine. The assembly includes an inlet throttle valve which controls the volume of oil flowed to the pump dependent upon the difference between the pump outlet pressure and a desired outlet pressure determined by an electronic control module for the diesel engine. The assembly also includes a crank shaft with an interior drain passage.

Abstract: A pump assembly having a piston pump, which is driven by an eccentric element. To prevent leakage brake fluid from reaching an eccentric element chamber, a groove surrounds the pump piston in the pump housing and a seal and a porous metal sintered ring is inserted into the groove. A drain which extends obliquely downwardly from the groove drains leakage fluid from the sintered ring.

Abstract: A drip ring for use with a hydraulic cylinder is provided. The drip ring is prefabricated from a flexible material. To size the prefabricated drip ring, the drip ring is cut and wrapped around the hydraulic cylinder that is to be fitted. The amount of excess drip ring material is measured and removed. The properly sized drip ring is then placed around the cylinder such that the two cut edges are positioned within a bonding fixture that has been pre-filled with a bonding compound. The inner flange of the drip ring is secured against the hydraulic cylinder with an adjustable, metal restraining strap. If desired, a drain fixture coupled to a drain pipe is attached to the fitted drip ring.

Abstract: The invention depicts and describes a clamping device for securing a draw-in bolt (12) on a machine table, a baseplate, or the like, having a piston (6) that is arranged movably in a cylinder bore (4) to form a pressure chamber (5), a cover (9) that closes off the cylinder bore (4) on the side opposite the pressure chamber (5), a receptacle (11) which is configured in the piston (6) and/or the cover (9) and into which a draw-in bolt (12) can be inserted, and a clamping mechanism in order to secure a draw-in bolt (12) in the receptacle (11), the clamping mechanism being actuable by displacement of the piston (6) between a clamped position into which it is pushed by spring elements (10) that are arranged in a spring chamber (2) provided between the piston (6) and cover (9), and a released position into which it can be brought by impingement of a hydraulic medium on the pressure chamber (5), which is characterized in that the spring chamber (2) is connected to the receptacle (11) by at least one runoff duct (19)

Abstract: The invention relates to a clamping cylinder for operating, for instance, a chuck by means of a pull pipe or pull rod installed preferably in a turning machine. The clamping cylinder has a cylinder casing (4) comprising a screwed-on cover plate (5), an axially displaceable piston (12) in the work chamber (11) of the cylinder casing (4) to produce the clamping force and a distributor (2) fixed onto one of the cylinder casing faces with ports and pressure lines for supplying and discharging a pressure oil to and from the work chamber of the piston. According to the invention, the cylinder casing (4), its lid (5) and the distributor casing are made of a light metal in order to reduce inertia moments and wear and to improve lubrication and heat dissipation. The walls of the locating bores for the piston (12) and/or its piston rods (13, 22) are hard coated. The piston and its two piston rods are made in a single piece from a tool steel and their respective contact surfaces are hard chrome coated.

Abstract: There is provided a high pressure fuel pump which includes a reliable fuel seal having a long durability and which can be produced at a relatively low cost. When a rotating shaft 4 is rotated to rotate a swash plate 7, such rotation is transmitted to a piston shoe guide plate 8 through a thrust ball bearing 9. Since the plate 8 is supported by a spherical portion 16 of a rod 14 mounted to a body 12, the plate 8 performs a precession to recurrently operate a plurality of fuel pumps 21 to 25 disposed around the rod 14. Each of the fuel pumps 21 to 25 includes a bellows provided between an outer end of the piston and the body 12, and the bellows completely seals a fuel leaked from a sliding clearance between the piston and the cylinder. Since the leaked fuel is introduced into a return passage 19 through a groove formed in an outer wall of the cylinder, a large internal pressure is not applied to the bellows and therefore, the bellows can be made of a low-priced material such as Teflon.

Abstract: A communication path (32) for communicating a hermetically closed space (S) with an inlet port (20) is formed within a casing (1). An oil reservoir (30) having an inside capacity much greater than an inside capacity of the communication path (32) is formed in an intermediate part of the communication path (32).

Abstract: A positive displacement pump includes a deformable hollow member for delivering a subject liquid by a cycle of contraction and restoration of its volume, a casing which contains the hollow member, and a pressurizing device for supplying and evacuating a hydraulic liquid in an annular space between the casing and the hollow member. The supplying of hydraulic fluid causes the contraction of the hollow member, and the evacuating of the hydraulic fluid causes the restoration (expansion) of the hollow member. A guide structure contacts and deforms the outer circumferential portions of the hollow member as the hollow member continues to expand to determine an initial contraction position of the hollow member. That is, a particular direction of contraction of the hollow member is set by the guide structure. Drive means periodically vary the circumferential position of the guide means relative to the hollow member to vary the initial contraction position of the hollow member.