Abstract: The invention relates to a supply device for the supply of pressure fluid into at least one vehicle brake, into a pressure fluid reservoir or into a pressure fluid accumulator, with a pressure fluid inlet and a pressure fluid outlet as well as with the following features: a piston is movably arranged in an accommodating member and has at least two hydraulically active diameters for the supply in the direction of the pressure fluid outlet, at least one non-return valve is used for the ventilation of a working chamber into which the piston is immersed. It is the essence of the invention that the piston has a multi-part design and comprises at least two synchronously movable partial pistons, with the first partial piston exhibiting the first hydraulically active diameter, and the second partial piston exhibiting the second hydraulically active diameter.

Abstract: A piston pump having a retaining device for retaining a spring element for restoring a closing element of a valve; the retaining device includes a receiving region for receiving and bracing the spring element and an integrally formed sealing region, in order to seal off a pressure chamber from a low-pressure region of the piston pump.

Abstract: A positive displacement pump (1) for transporting a fluid with automatic adaptation to the compressibility of that fluid has a pumping chamber (15) with a variable volume (V) which is on the one hand delimited by a rigid chamber cover plate (10) and on the other hand by an elastic diaphragm (9), a suction channel (29) which is in flow connection with the pumping chamber (15) for sucking the fluid to be transported into the pumping chamber (15), an outlet channel (24) which is in flow connection with the pumping chamber (15) for discharging the fluid to be transported from the pumping chamber (15), and a drive device (29) for cyclically increasing and reducing the current volume (V) of the pumping chamber (15), with the drive device (29) being connected to the diaphragm (9) by means of a diaphragm connecting element (34; 34a; 34b) which is spring-mounted in the drive device (29) by means of a spring element (33; 33a; 33b).

Abstract: A combination compressor and vacuum pump apparatus comprising a common drive mechanism, a compressor piston-cylinder unit mechanically coupled to the drive mechanism, the compressor piston-cylinder unit comprising a hollow first piston rod connected to the drive mechanism at a first free end substantially opposite a first piston operable within a first cylinder so as to form the compressor piston-cylinder unit, and a vacuum pump piston-cylinder unit mechanically coupled to the drive mechanism, the vacuum pump piston-cylinder unit comprising a hollow second piston rod connected to the drive mechanism at a second free end substantially opposite a second piston operable within a second cylinder so as to form the vacuum pump piston-cylinder unit, whereby air is pulled into the compressor piston-cylinder unit through the first piston rod for compression therein and air is exhausted from the vacuum pump piston-cylinder unit through the second piston rod.

Abstract: A pump including a main body having a piston provided in a portion of the main body, the piston being configured to reciprocate linearly. A piston spring may be provided within the main body and configured to bias the piston toward an end of the main body. Further, a plurality of intake check valves may be positioned radially within the main body and configured to move in a direction generally perpendicular to the linearly reciprocating direction of the piston such that brake fluid is introduced into the main body. Additionally, the pump may include an exhaust check valve configured to exhaust brake fluid from an inside of the main body to an exterior of the main body by moving an exhaust check ball in the linearly reciprocating direction of the piston.

Abstract: A pressure storage structure for use in air is disclosed.

Abstract: A battery operated, handheld fluid dispenser comprises a supply container having a body portion and a narrow neck extending upwardly therefrom. A pump and discharge unit is mounted on the upper end of the neck and comprises a pump diaphragm and pump chamber for pumping liquid from the container to a discharge nozzle. A battery powered pump drive unit is mounted on the container and comprises an electric motor having an output shaft coupled with the pump diaphragm through a cam and cam follower arrangement to displace the diaphragm through a pump stroke when the motor is energized. The cam is rotatably driven by the motor, and the cam follower is attached to the diaphragm, whereby rotation of said cam axially displaces the diaphragm, and the cam and cam follower have interengaging dual cam faces for balancing lateral forces therebetween during rotation of said cam relative to said cam follower.

Abstract: A liquid pump includes an electronically controlled throttle inlet valve to control pump output. With each reciprocation cycle, a plunger displaces a fixed volume of fluid. When less than this fixed volume is desired as the output from the pump, the electronically controlled throttle inlet valve throttles flow past a passive inlet check valve to reduce output. As a consequence, cavitation bubbles are generated during the intake stroke. Cavitation damage to surfaces that define the inlet port passage are avoided by a specifically shaped and sized cavitation flow adjuster extending from the valve member of the passive inlet check valve. By positioning the cavitation flow adjuster in the inlet port passage, a flow pattern is formed in a way to encourage cavitation bubble collapse away from surfaces that could result in unacceptable cavitation damage to the pump.

Abstract: A pump assembly includes a cam member arranged to rotate about an axis, and a piston pump having a cylinder body with a biased piston drivingly displaceable within the cylinder body and engageable with the cam member such that rotation of the cam member corresponds to reciprocating movement of the piston. The pump assembly is arranged for use in a food cutting machine for transporting cooling fluid from a reservoir to at least one bearing arrangement provided to support a rotating shaft.

Abstract: A fuel pump for an internal combustion engine including a fuel pump housing, a cylindrical bore having a central axis and being defined by a bore wall surface, a receiving hole formed in the housing, and a tappet assembly received in the cylinder bore. The tappet assembly includes an outer peripheral surface with an elongated key slot longitudinally extending parallel to the central axis. A guide key partially received in the receiving hole is provided, the guide key including a head that extends into the cylindrical bore to engage the elongated key slot of the tappet assembly. The head has an outer dimension that is larger than a dimension of the receiving hole along the central axis. Methods for guiding a reciprocating tappet assembly in a fuel pump and assembling a fuel pump are also provided.

Abstract: A high pressure pump for preventing distortion of a sealing surface or a cylinder form. The high pressure pump has an intermediate member including a cylinder body having a pressurizing chamber communicated with a cylinder accommodating a plunger. Fluid in the pressurizing chamber is pressurized by reciprocating the plunger. The intermediate member is arranged between a cover and a flange and is clamped by clamping bolts. An electromagnetic spill valve for receiving reaction force from the pressurizing chamber when the fluid in the pressurizing chamber is pressurized is attached to the cover at a position for reducing the clamping force applied to the intermediate member by the clamping bolts.

Abstract: A piston pump for brake systems employs a pulsation-smoothing device that functions especially well in the region of the outlet valve. As a result, substantially less noise occurs, and the durability of the piston pump is substantially better. The piston pump is used essentially in traction-controlled motor vehicle brake systems.

Abstract: A high-pressure a radial piston fuel pump in which the intake valves are embodied as ball valves, which has an advantageous effect on the efficiency of the high-pressure fuel pump. Moreover, the production and assembly of the high-pressure fuel pump of the invention are simplified by the use of ball valves.

Abstract: A filter to be mounted in a valve seat member for filtering liquid is proposed which can be manufactured without a drawing step, thereby improving productivity and cost performance of a piston pump in which such a filter is mounted. The filter is a flat metal plate including a main body formed with a plurality of filter holes in a central portion thereof, and a plurality of projections integrally and radially outwardly extending from a perimeter of the main body so as to be circumferentially spaced apart from each other. The filter is pushed into a filter mounting hole formed in a valve seat member of a discharge valve in a piston pump with the projections bent toward the opening of the filter mounting hole while being pressed against the inner surface of the filter mounting hole under an elastic restoring force and fixed to the valve seat member.

Abstract: A high pressure pump for decreasing an initial axial force of a clamping bolt and preventing distortion of a sealing surface and a cylinder form. The high pressure pump has an intermediate member including a cylinder body. The cylinder body has a pressurizing chamber communicated with a cylinder accommodating a plunger. Fluid in the pressurizing chamber is pressurized by reciprocating the plunger. The intermediate member is arranged between a cover and a flange and clamped by a clamping bolt. The clamping bolt has an exposed area at its axially central area where the entire periphery of the clamping bolt is exposed from the cover and the flange. One or both of the cover and the flange clamp the intermediate member with a flexing elastic force.

Abstract: A piston (6) of a piston pump unit (2), which can be displaced in a translatory manner, is guided in a cylinder bore (7). The piston (6) is driven by a crank drive (13) comprising an eccentric element (15) which is arranged on a drive shaft (14). A stroke ring (12) is rotationally mounted on the eccentric element (15) but does not rotate therewith. A sliding surface (10) of the piston (6) is arranged on a sliding bearing surface (11) on the stroke ring (12). A discharge chamber (22) is embodied inside the piston (6) on an end opposite the stroke ring (12). Said discharge chamber is open towards the sliding bearing surface (11). The discharge chamber (22) is connected in a pressure-wise manner to a working chamber (8) by means of a passage (23) in the piston (6). A displaceable control piston (25) is guided in a longitudinal bore (24) pertaining to said passage (23).

Abstract: In a high pressure fuel supply pump, a housing is provided with a through-hole having a step. A plunger is slidably accommodated in the through-hole on an axial end side thereof. An intake valve member is positioned in the through-hole on an axially opposite side to the plunger with respect to the step so that a pump chamber is formed between the plunger and the intake valve member. A discharge valve member is positioned in the through-hole on an axially opposite side to the plunger with respect to the intake valve member. A plug is screw fastened into an inner wall of the through-hole on another axial end thereof so as to urge both of the discharge valve member and the intake valve member against the step so that the intake valve member and the discharge valve member are rigidly fixed in the through-hole.

Abstract: A medium pump for a motor includes a pump case with a pump cylinder and a pump piston positioned displacaebly in the pump cylinder in the direction of a pump axle. The pump piston rotates about the pump axle by running off an oblique control surface and realizes axial pump movements against the pressure of a first spring. A pump lift adjusting device is removably positioned in a guide placed transversely to the pump axle and fixedly connected with the pump case.

Abstract: A pump used in vehicle controlled braking systems provides a reverse direction of flow through a cylinder bore of the pump and utilizes an inlet check valve located outside of the piston at the end of the cylinder bore opposite the piston, in conjunction with an outlet check valve located in an outlet extending through a sidewall of the cylinder bore of the pump. The inlet check valve is assembled and tested as a module prior to being installed in the pump. A fluid reservoir, having a movable wall, is connected to the inlet to facilitate priming the pump module. The piston is driven by a self-supporting drive apparatus with an eccentric element affixed to a stub shaft, or by other forms of a drive apparatus having an eccentric element fixed to a motor drive shaft.

Abstract: A piston pump assembly with a rotatingly driven swashplate in driving relationship with a rocker arm and piston engaged with one end of the rocker arm. A spring urges the rocker arm and piston into contact with an annular ring carried by a bearing in the swashplate. The spring may be a separate leaf spring or may be formed integrally with the rocker arm. The rocker arm engagement with the piston uses a spherical ball-joint-like surface. The contact between each of the rocker arm and piston and the annular ring utilize spherical surfaces on the rocker arm and piston, with an elongated footprint on the rocker arm and a circular footprint on the piston. The piston is allowed a slight radial play in operation.

Abstract: A peristaltic piston pump driven by a dedicated pump cam disposed on a camshaft of an engine. A plurality of valve-opening cams are disposed along the camshaft. The pump cam has a plurality of lobes equal in number to the number of valve cams and each pump lobe is disposed at 180° from a valve cam lobe such that the camshaft valve torque and secondary oil pump camshaft torque partially cancel, reducing overall camshaft torque oscillation. The pump includes a lost-motion shuttle and spring to permit continuous response of the pump to the cam.

Abstract: A dispenser has a seal disk (30), a valve member (40), a plunger guide block (50), a motor (3), which rotates a cam-follower guide block (60), and an end cam (5). The seal disk (30) has communication holes (31), (32) and a sliding surface (33). The valve member has a sliding surface (41), three plunger holes (42) and three plungers (80) inserted in the plunger holes. The cam-follower guide block (60) has three guide holes (62) that receive cam followers, which each have a body (70) with a ball (75) within a recess (71). The ball (75) contacts the cam surface (5A) of the cam (5) which causes the cam followers and plungers (80) to move back and forth parallel to the dispenser axis. The coefficient of friction between the ball and the recess is less than that between the ball and the cam surface (5A).

Abstract: A piston pump for brake systems the region of the outlet valve is provided with a pressure chamber, an opposing chamber, and a flexible wall that divides the pressure chamber from the opposing chamber. The flexible wall has an elastically resilient diaphragm that is supported in an elastically flexible body.

Abstract: In a piston pump for providing high-pressure fuel in a common-rail fuel injection system including a camshaft (2), which is mounted rotatably in a pump housing (1) and which has at least one eccentric cam 93) for operating a pump piston (4, 14) in an approximately radial direction with respect to the camshaft (2), in order to reduce the wear of the piston pump, a piston-rod element (6, 16, 26, 36, 46) is arranged between each pump piston (4, 14) and the eccentric cam (3) so as to transmit the stroke movement (5) and the force from the eccentric cam of the camshaft (2) to the pump piston (4, 14) by a rolling movement.

Abstract: A method of controlling the fuel injection to a combustion chamber (4), comprises the steps of: supplying fuel to a pump (2), which has a piston (7) reciprocating in the a cylinder (6), pressurizing the fuel by applying a force onto the piston (7) by an actuator (8), so that the piston (7) is displaced from a first end position (9) towards a second end position (10), injection of fuel corresponding to a partial volume of the fuel pressurized in the cylinder (6), into the combustion chamber (4), and returning the piston (7) towards the first end position (9) by the pressurized fuel, so that the piston (7) acts with a driving force on the actuator (8). The invention also relates to a fuel injection device for carrying out the method.

Abstract: Disclosed herein is a fuel pump for an inter-cylinder direct fuel injection apparatus, in which occurrence of corrosion and attrition caused by cavitation or erosion can be suppressed, their resistance against the environment can be improved, and an excellent lifetime can be achieved in the case of the use of an aluminum material even if the temperature reaches as high as 100° C. or higher and the pressure reaches as high as 7 to 12 MPa. In the fuel pump for an inter-cylinder direct fuel injection apparatus, made of aluminum or an aluminum alloy, a coating film plated with Ni—P or a Ni—P based material is formed by electroless plating.

Abstract: A hydraulically driven diaphragm pump with a diaphragm clamped at its edge between a pump body and a pump cover separating a delivery chamber from a hydraulic chamber and pretensioned in the direction of its intake stroke by spring force. A hydraulic diaphragm drive in the form of an oscillating displacement piston is displaceable in the pump body between a reservoir chamber for the hydraulic fluid and the hydraulic chamber. The diaphragm is so strongly pretensioned by spring force that it exerts a substantial compressive force on the hydraulic fluid in the hydraulic chamber. Therefore a substantial hydrostatic pressure is built up in the hydraulic chamber relative to the delivery chamber.

Abstract: The present invention related to a piston pump, in particular for controllable brake systems such as ABS or ESP, wherein a working chamber of the pump in front of a piston is delimited by a pressure valve, and a resetting spring with its one end is supported on a valve seat carrier of the pressure valve and with its other end resets said piston into its bottom dead center position. An object is to render the assembly of the mass-produced pumps as inexpensive and simple as possible. To achieve this object, the present invention discloses that the resetting spring be adapted to be attached directly or indirectly to the valve seat carrier in addition.

Abstract: In a fuel injection pump, a helical gear is attached to an end of a camshaft and rotatable with the camshaft. The camshaft is biased in one axial direction thereof by a driving force that the helical gear receives from an engine crankshaft. A disk is provided in a position of the camshaft extending forward from a cam to the direction in which the camshaft is biased. An axial movement of the disk is restricted via a washer by an end of a bearing cover. The disk is formed in the same axis to a portion of the camshaft that is held by a journal bearing. An outer diameter of the disk is larger than that of the cam. An area where the disk and the washer are in sliding contact with each other is relatively large and the sliding regions thereof are constant so that hammer noises are prevented and frictional wear thereof are limited.

Abstract: A magnet pump includes a synthetic resin casing, divided into a front casing and a rear casing and configured to internally form an impeller housing chamber and a magnet can housing chamber contiguous thereto, having an inlet and an outlet for a target fluid to be transferred. The casing forms an eddy chamber at a position for dividing the front casing and the rear casing along the outer rim of the impeller housing chamber to surround the outer rim of the impeller. The eddy chamber has overhangs formed at an entry of the eddy chamber hanging over from both sides in the rotational-axis direction of the impeller.

Abstract: A hydraulic pump unit for vehicle brake control system comprising a pump housing, a cylinder received in a receiving hole formed in the pump housing. The cylinder has a bottom portion and is provided at the bottom portion with an outlet valve. A plunger is slidingly received in the cylinder and defines a pump chamber in cooperation with the cylinder. An inlet valve provided on the plunger, an inlet passage formed in the pump housing. An opening of the inlet passage is provided in the receiving hole. An outlet passage formed in the pump housing, an opening of the outlet passage is provided in the receiving hole. A plug member for closing an opening of the receiving hole, the plug member is fixed to the bottom portion of the cylinder, and an orifice plate having a passage is arranged between the bottom portion and the plug member.

Abstract: A peristaltic piston pump driven by a dedicated pump cam disposed on a camshaft of an engine. A plurality of valve-opening cams are disposed along the camshaft. The pump cam has a plurality of lobes equal in number to the number of valve cams and each pump lobe is disposed at 180° from a valve cam lobe such that the camshaft valve torque and secondary oil pump camshaft torque partially cancel, reducing overall camshaft torque oscillation. The pump includes a lost-motion shuttle and spring to permit continuous response of the pump to the cam.

Abstract: A rotation-to-linear motion transforming mechanism equipped with a safeguard is provided. The mechanism includes an eccentric cam coupled to a torque input shaft, a cam ring placed in contact of an inner wall thereof with the eccentric cam, and a plunger placed to be movable linearly following rotation of the cam ring. The safeguard is provided in the cam ring which is responsive to application of an excessive torque to the cam ring to break the cam ring, thereby interrupting transmission of torque to the plunger from the torque input shaft. This avoids breakage of the plunger or the whole of the rotation-to-linear motion transforming mechanism. A fuel injection pump equipped with such a safeguard is also provided.

Abstract: In a seal mechanism which constitutes a port switching portion in a pump mechanism of a paste ejection apparatus that ejects paste, and which prevents leakage of the paste from a seal portion between a plunger block rotating with a plunger and a fixed seal block (between a seal surface and a sliding surface), a housing portion is formed by opposing an outer surface provided for the seal block to an inner surface extending axially from the cylinder block, and a ring-shaped external seal member formed by combination of an O-ring and self-lubricant material such as PTFE is attached into the housing portion. Hereby, it is possible to prevent the paste that has leaked from the seal portion from leaking to the outside of the housing portion by the external seal member.

Abstract: In a fuel supply pump, a fuel relief path relieves a part of fuel, which is supplied through a part of fuel supply path connected between a control valve and a compressing chamber of a pump element, into a slidably contact portion between a plunger of the pump element and a plunger driving unit.

Abstract: A tappet turning prevention structure for a fuel supply apparatus includes a piston defining a fuel pressurizing chamber within the housing. A tappet disposed at one end of the piston has accommodated in it a roller driven by a cam of an engine and a roller supporting pin for transmitting a force from the cam to the piston. The tappet is housed by a bracket which has one or two grooves in an inner surface of it for supporting the roller supporting pin at one or both ends. The number of parts can be decreased because the turning prevention pin for the tappet and the roller supporting pin is a single common pin, and therefore the need of controlling of the press-fit loads is eliminated because no process for thrusting the tappet turning prevention pin into the outer circumference of the tappet is involved.

Abstract: A pump used in vehicle controlled braking systems provides a reverse direction of flow through a cylinder bore of the pump and utilizes an inlet check valve located outside of the piston at the end of the cylinder bore opposite the piston, in conjunction with an outlet check valve located in an outlet extending through a sidewall of the cylinder bore of the pump. The inlet check valve is assembled and tested as a module prior to being installed in the pump. A fluid reservoir, having a movable wall, is connected to the inlet to facilitate priming the pump module. The piston is driven by a self-supporting drive apparatus with an eccentric element affixed to a stub shaft, or by other forms of a drive apparatus having an eccentric element fixed to a motor drive shaft.

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: In piston pumps for brake systems used until now, there were often noise problems, from pressure pulsations.

Abstract: A high pressure feed pump which includes a cylinder 12 which has a central bore which mounts a delivery piston 14 for reciprocation. The delivery piston is reciprocated by a rotating drive shaft 28 which has an eccentric journal 36 formed thereon, and a rolling ring 40 is rotatably mounted on the eccentric journal. A plate-like spring element 62 is positioned between the front end of the delivery piston and the rolling ring. Also, either the front end of the delivery piston or the side of the spring element which faces the delivery piston, is a concave configuration, so that at maximum pressure loading, the spring element is deformed into the concave region.

Abstract: The invention relates to a hydraulic pump unit having a plurality of pump elements, disposed in one plane, each of which has one pump cylinder and one pump piston longitudinally displaceable in the pump cylinder, and whose longitudinal axes intersect at a common intersection point, and having a cam drive with cams, which upon a rotation of the cam drive relative to the pump elements act upon the pump pistons with an actuating motion. To enable a uniform pumping of the hydraulic fluid and to make a high degree of smoothness of the hydraulic pump unit possible, it is proposed that the number and the angular spacing of the cams is adapted to the number and angular spacing of the pump elements in such a way that when a certain number of pump pistons are located at top dead center, the same number of pump pistons are at bottom dead center.

Abstract: A piston pump comprises cylinder attached within a cavity of a pump housing. An outlet check valve seat is defined about an outlet of the cylinder. A piston is slidably received in a bore of the cylinder and has a first passageway formed therein. A cylinder head encloses the outlet of the cylinder and defines a second passageway therein. The first passageway has an inlet in fluid communication with the cavity of the pump housing, and an outlet in fluid communication with a pumping chamber defined in the pump housing. A first spring retains the piston to the cylinder. A first check valve member is a ball retained near a valve seat formed in the first passageway of the piston by a disk spring, and allows fluid to flow only from the inlet to the outlet of the piston.

Abstract: A high pressure fuel pump for an internal combustion engine having a cylinder, a plunger slidably fitted in the cylinder and a seal mechanism for blocking fuel leakage from an end of a sliding portion between the cylinder and the plunger and also for preventing an lubricant for a driving mechanism of the plunger from entering into the cylinder from the end of the sliding portion of the cylinder and the plunger. A holder surrounding the end of the sliding portion of the cylinder and the plunger is provided. The seal mechanism comprises two mutually independent seal devices mounted with a specific spacing in a longitudinal direction from the end of the sliding portion of the cylinder and the plunger along a circumference of the plunger. The two seal devices are held on the circumference of the plunger by the holder surrounding the end of the sliding portion of the cylinder and the plunger while keeping the specific spacing.

Abstract: A high-pressure fuel pump of a simple construction is capable of distributing the position of contact between a tappet and a cam so as to improve durability of the tappet without causing seizure of a piston. A cylinder is arranged in a housing, and the piston is received in the cylinder for sliding reciprocation so that fuel is sucked into the cylinder and pressurized by the piston. The tappet is arranged inside one end of the housing for reciprocation, and contacts the cam, which rotates with a camshaft of an engine, so as transmit a driving force of the engine to the piston. A sleeve is arranged between the tappet and the housing, and clearance fitted to an outer peripheral surface of the tappet and an inner peripheral surface of the housing. The tappet is caused to rotate on its own axis by a frictional force generated between the cam and the tappet.

Abstract: A high pressure fuel pump having a variable fuel injection rate, including a pump body, a pump cylinder formed in the pump body and a piston reciprocable within the pump cylinder, which defines a pressurization chamber. The pump piston has a reduced diameter portion which provides a primary piston. A piston annulus is slidably mounted thereon and provides a secondary piston. An annular actuation chamber adjoins the secondary piston opposite the pressurization chamber. An actuation passage is provided between a return fuel drain and the actuation chamber, which is selectively open or closed passively by pump piston movement and/or dynamically by operation of an actuation solenoid valve. If the actuation chamber passage is open, then during the pressurization stroke the secondary piston will remain stationary relative to the pump body, but if it is closed then the secondary piston must stroke in unison with the primary piston.

Abstract: In a fuel injection pump, fuel pressurized by a feed pump is supplied to an accommodation chamber via a communication path having an orifice. An end of the communication chamber on a side of the accommodation chamber is positioned to face an axial end of a minute space between sliding contact portions of a cam and a bush when the cam is at a given angular position. The fuel fed from the feed pump is injected from the end of the communication path axially deep into the minute space between the sliding contact portions so that oil film for lubrication is formed on the sliding contact portions, resulting in suppressing frictional seizure of the sliding contact portions.

Abstract: A piston pump (20), in particular a high-pressure pump for a fuel system of an internal combustion engine, includes a housing (72). In addition, a piston (94) is provided, which defines a working chamber 100. A drive shaft (78) is supported in the housing (72) by means of at least one shaft bearing and has at least one crank section (86). A piston bearing supports the piston (94) at least indirectly against the crank section (86) of the drive shaft (78). At least one of the bearings between parts that move in relation to one another is a hydrostatic bearing (62). This hydrostatic bearing is connected to the working chamber (100) by means of a fluid connection. In order to increase the efficiency of the piston pump (20), the invention proposes that the fluid connection between the working chamber (100) and the hydrostatic bearing (62) be provided with a device (56; 118) that can intermittently interrupt the fluid connection.

Abstract: The present invention provides a piston type small discharge pump capable of reducing a dead volume and effects of unbalanced load to the piston shaft, and being self-priming. The fluid taken through a inlet port is introduced into a cylinder portion via a flat type check valve, and discharged into a discharge port through a discharge hole and a check valve as a piston moves up and down. A flat type check valve is provided in the vicinity of a bottom dead center of the piston and a spring for biasing the piston upwardly is provided outside the cylinder portion, thus reducing the dead volume.

Abstract: The invention relates to a piston pump for increasing pressure for liquids, in particular for the camshaft phase adjustment of reciprocating internal combustion engines, said piston pump advantageously being integrated into the housing of the cylinder head. The piston pump for increasing pressure is defined in that it increases an existing fluid pressure to a required fluid pressure and keeps this pressure virtually constant. The piston pump for increasing pressure is advantageously pre-assembled in a sleeve.

Abstract: In order to provide a fuel pump in which a piston spring arrangement can be made of inexpensive material, knocking noises of a piston are reduced, and components related to the piston are protected against breakdown, a piston-following spring is provided between a fuel pump body and the piston to lower the piston in response to the rotation of an eccentric cam. A pumping member-moving spring is provided between the fuel pump body and a pin connected to a pumping member, and lowers the pumping member when the piston is moved down. The downward movements of the piston and the pumping member are caused by the springs, so that these springs can be made of inexpensive materials, and enable the piston to reliably follow the eccentric cam.