Abstract: A wrist pin cap for a piston. The wrist pin cap is configured to form an interference fit with the piston. In specific embodiments, the wrist pin cap is positioned within the piston adjacent to an end of a wrist pin. In certain specific embodiments, the wrist pin cap is configured to form an interference fit with a counterbore of the piston. Some specific embodiments include a method for shrink fitting a wrist pin cap within a piston. In more specific embodiments, the wrist pin cap is shrunk by an application of liquid nitrogen.

Abstract: A piston may include a splitting internal cooling runner, an end portion recessed inward to form a combustion chamber, and an annular internal cooling runner at least partially surrounding the combustion chamber. A wall of the annular internal cooling runner may partially protrude in a direction away from the end portion to form an annular splitting portion which divides the annular internal cooling runner into an outer half cavity and an inner half cavity.

Abstract: Various implementations include a combustion engine piston, including a skirt in a counter-part and including a first contact area of the piston in the counter-part, a head which extends transverse to a central axis, and a ring carrier which comprises at least two lands and at least two grooves for receiving the rings, including a first land adjoining the head and a second land situated between the first land and the skirt, wherein the lands include at least one contact land having a diameter greater than a minimum diameter of the skirt to form a second contact area of the piston in the counter-part, and wherein at least one contact land comprises a friction-reducing surface coating, formed at least on a radial sector covering an angle of at least 30 degrees, and up to on a single sector covering an angle of 360 degrees.

Abstract: In the specified cylinder, the heat shield film is formed on the top surface of the piston, the surface of the parachute part of the exhaust valve, and the wall surface of the exhaust port. On the other hand, in cylinder other than the specified cylinder, the heat shield film is formed only on the top surface of piston. The heat shield film is also formed on the inner wall of the exhaust manifold, the inner wall of the exhaust pipe, and the inner wall of the housing. Among the exhaust manifold, however, the heat shield film is not formed on the inner wall of the branch pipe connected to the exhaust port of the other cylinder.

Abstract: Positive displacement machines and methods therefor capable of increasing a load-carrying capacity of a piston-cylinder lubrication interface of positive displacement machines having a cylinder block, a cylindrical bore defined in the cylinder block, a piston reciprocably disposed within the cylindrical bore, and a working fluid within the piston-cylinder lubrication interface to provide a load-bearing function between the piston and the bore wall of the cylinder bore. The method includes providing at least one circumferential groove on a bore wall of the cylindrical bore within the piston-cylinder lubrication interface having an opening facing the piston and that is in fluidic communication with the piston-cylinder lubrication interface so as to contain a portion of the working fluid, and operating the positive displacement machine such that the working fluid enters the cylindrical groove and promotes hydrostatic balancing of pressure of the working fluid within the piston-cylinder lubrication interface.

Abstract: A cold trap is provided between a vacuum chamber and a vacuum pump. The cold trap includes a cold panel and a cold panel chamber that surrounds the cold panel in an exhaust passage. The cold panel includes an expansion panel outside the cold panel chamber. The expansion panel is located in the vacuum chamber.

Abstract: A hydraulic pump, in particular an adjustable axial piston pump, has at least one piston (22) movable in a reciprocating manner in a longitudinal direction within a pump housing during operation of the hydraulic pump. The piston (22) has a link head (24), a piston top (54) opposite the link head (24), and at least one hollow chamber (60) surrounded at least partially by a piston housing (62) that substantially or completely terminates each hollow chamber (60) towards the outside. A piston (22) for such hydraulic pump is also provided.

Abstract: A sliding device includes a sliding bearing, and a shaft which is rotatable and in slidable contact with the sliding bearing in presence of a lubricating oil. The sliding bearing has a surface hardness smaller than a surface hardness of the shaft. Additionally, the sliding bearing has a surface roughness Ra of not larger than 0.2 micrometer, and the shaft has a surface roughness of not larger than 0.05 micrometer.

Abstract: A refrigerant compressor comprises an electric element; a compression element; and a sealed container; wherein the compression element includes: a crankpin; a piston pin; and a connecting rod having a large hole portion into which the crankpin is inserted, a small hole portion in which the piston pin is rotatably disposed, and a coupling rod portion; wherein an oil guide hole is provided in the coupling rod portion of the connecting rod such that the large hole portion and the small hole portion are communicated with each other via the oil guide hole; a circular first groove is provided on an outer peripheral surface of the piston pin such that the first groove communicates with the oil guide hole; and a second groove extending in a center axis direction of the piston pin is provided in a first region of the small hole portion of the connecting rod.

Abstract: A piston ring has a body member for sitting in a ring groove of a piston. The body member has an inner periphery, upper wall, lower wall and an outer periphery. The outer periphery has a concavity therein for storing lubricant therein. The upper wall has an outer section proximate to the outer periphery is constructed to be resiliently flexible between a flexed and unflexed position such during a portion of a power stroke, the volume of the concavity to store the lubricant is decreased by the flexing of the upper wall to the flexed position for expelling lubricant therefrom to a wall of the cylinder. The wall resiliently returns to the unflexed position during other times to allow excess lubricant from the wall of the cylinder to pass into the concavity.

Abstract: To improve productivity and increase seizing resistance and abrasion resistance of a sliding surface of a tilt adjustment cylinder, a plurality of pistons are arranged cirumferentially in a cylinder block configured to rotate with a rotating shaft. Tip end portions of the pistons slide along the swash plate, and the pistons reciprocate. The swash plate is supported to tilt with respect to the rotating shaft. Further, a tilt adjustment driving portion is included. The tilt adjustment driving portion includes tilt adjustment large- and small-diameter cylinder chambers and tilt adjustment large- and small-diameter pistons configured to slide in the cylinder chambers to change the tilt angle of the swash plate. A sliding surface of the inner peripheral surface of each of the cylinder chambers includes a quenched portion formed by quenching using laser light, the sliding surface being a surface on which the tilt adjustment piston slides.

Abstract: A hermetic compressor includes a closed vessel for storing lubricating oil, an electric-driving element, and a compressing element driven by the electric-driving element. The compressing element includes a cylinder block forming a compression chamber, a piton that reciprocates inside the compression chamber, and an oiling device for supplying the lubricating oil to an outer circumference of the piston. A first oil groove is concavely formed on the outer circumference of the piston, and a second oil groove is concavely formed on a side opposite to the compression chamber relative to the first oil groove. The second oil groove has a spatial volume same or greater than that of the first oil groove. An expanded clearance portion is provided such that a clearance between the piston and the cylindrical hole portion broadens from a top dead point to a bottom dead point.

Abstract: A gas lubrication structure is provided with a high-temperature-side cylinder, an expansion piston lubricated relative to the high-temperature-side cylinder by gas, and a layer provided to the outer peripheral surface of the expansion piston and composed of a material flexible and having a higher linear expansion coefficient than the base material of the expansion piston. The thickness of the layer under normal temperatures is not less than the size of the clearance formed between the layer and the high-temperature-side cylinder. Also, even if the layer is thermally expanded under use conditions, the layer under normal temperatures has a thickness enabling a clearance to be formed between the layer and the high-temperature-side cylinder.

Abstract: A piston for an internal combustion engine has a piston head and a piston skirt. The piston head has a circumferential ring belt and a circumferential cooling channel. The piston skirt has a working surface assigned to its major thrust side and to its minor thrust side. A bore that proceeds from the cooling channel is provided, which ends in the working surface assigned to the major thrust side, and is disposed at an incline, in such a manner that the bore exit encloses an acute angle (?) with the center axis (M) of the piston. An opening is formed in the working surface, and a deflection surface inclined relative to the working surface is provided between the bore and the bore exit. The working surface assigned to the major thrust side has a depression which forms at least one oil capture region above the opening.

Abstract: A hydraulic system for use with a pressurized fluid includes a first cylinder and a second cylinder. A flow path links the first and second cylinders in fluid communication with each other. A first piston is disposed within the first cylinder and defines a first axis and a second piston disposed within the second cylinder. The first piston is movable along the first axis between a variety of operating positions and a rephasing position. The first piston has an exterior surface that defines a peripheral groove and several flutes. The flutes are oriented such that they are parallel to the first axis and intersect the peripheral groove, allowing the fluid to flow from the first cylinder across the flow path and into the second cylinder when the first piston is in the rephasing position thereby automatically rephasing the first and second pistons within the hydraulic system.

Abstract: A piston ring has a body member for sitting in a ring groove of a piston. The body member has an inner periphery, upper wall, lower wall and an outer periphery. The outer periphery has a concavity therein for storing lubricant therein. The upper wall has an outer section proximate to the outer periphery is constructed to be resiliently flexible between a flexed and unflexed position such during a portion of a power stroke, the volume of the concavity to store the lubricant is decreased by the flexing of the upper wall to the flexed position for expelling lubricant therefrom to a wall of the cylinder. The wall resiliently returns to the unflexed position during other times to allow excess lubricant from the wall of the cylinder to pass into the concavity.

Abstract: A drive mechanism for a hammer drill comprises a hollow piston 558 having a cylindrical bearing that is adapted to receive a crank pin in order to cause the hollow piston 558 to reciprocate inside a spindle 548. A plurality of longitudinal ridges 559 are formed on the outer surface of the hollow piston 558 to reduce the surface area of contact between the hollow piston 558 and the spindle 548, and a plurality of grooves 561 are formed in the gaps between the ridges. The grooves 561 are adapted to retain lubricant 563 in order to reduce frictional contact between the hollow piston 558 and the spindle 548.

Abstract: There is disclosed a radial piston machine comprising a cylinder block having at least one bore in which a piston supported on an eccentric disk is movably guided via roll bodies, wherein at least one hydrostatic relieving field is provided between the piston and the roll body. According to the invention, the active surface A2 of the relieving field is equal to or larger than the active piston area A1 of the piston restricting a cylinder chamber and the relieving field is in fluid communication with the cylinder chamber via a hydraulic resistance.

Abstract: A radial piston pump having external loading. The radial piston pump has an inner eccentric which is attached to a rotatable driveshaft, a cylinder block which has positionally fixed cylinder bores aligned radially with respect to the driveshaft, and displacement pistons which are mounted in a longitudinally movable manner in the cylinder bores. The displacement pistons have a piston head with a short casing height, and are mounted with their piston base on the eccentric, in such a way that the piston head, during its longitudinal movement, pivots in a predetermined angle range (??) about the longitudinal central axis of the associated cylinder bore.

Abstract: A hydrostatic axial piston machine utilizing a swashplate design has a cylinder drum (3) that is mounted so that it can rotate around an axis of rotation (2). The cylinder drum (3) is provided with cylinder bores (4), in each of which a piston (5) is mounted so that it can be displaced longitudinally. The pistons (5) are each supported on a swashplate (7) by a sliding element (6). Between the piston (5) and the cylinder bore (4), there is at least one annular groove (20; 20a, 20b) which is located in the area of the inner half (LFi) of the guided length (LF), such as the minimum guided length (LF) of the piston (5) in the cylinder bore (4).

Abstract: A piston is equipped with a skirt that has a sliding surface provided with an oil repellent resin layer. A solid lubricating resin layer and the oil repellent resin layer are exposed on the sliding surface. On the sliding surface, the oil repellent resin layer extends at an incline with respect to the centerline of the sliding surface in a circumferential direction of the piston.

Abstract: A gas lubrication structure is provided with a high-temperature-side cylinder, an expansion piston lubricated relative to the high-temperature-side cylinder by gas, and a layer provided to the outer peripheral surface of the expansion piston and composed of a material flexible and having a higher linear expansion coefficient than the base material of the expansion piston. The thickness of the layer under normal temperatures is not less than the size of the clearance formed between the layer and the high-temperature-side cylinder. Also, even if the layer is thermally expanded under use conditions, the layer under normal temperatures has a thickness enabling a clearance to be formed between the layer and the high-temperature-side cylinder.

Abstract: A piston includes an upper crown portion and a lower crown portion with a pair of pin bosses spaced for receipt of a connecting rod. The pin bosses have pin bores aligned with one another along a pin bore axis. The upper crown portion and the lower crown portion form an outer oil gallery and a central oil gallery. The central oil gallery is formed in part by a floor extending radially inwardly from the outer oil gallery to a plateau. To facilitate cooling the central gallery, the plateau has a through opening and the floor has at least one trough depending axially therein. At least one oil flow passage extends in fluid communication between the outer oil gallery and the central oil gallery, wherein at least one oil flow passage is axially aligned with the at least one trough to provide a direct flow of oil to the trough.

Abstract: A ported cylinder for a diesel engine includes a circular groove in the bore, located on the outside of respective port. An oil wiper ring or a group of oil wiper rings is seated in the circular groove for wiping excess lubricating oil from a piston surface. A compressing ring is disposed between the oil wiper ring or group of oil wiper rings and the floor of the circular groove to urge the oil wiper rings into contact with the piston surface. An oil wiper ring construction includes a major surface with oil-conducting channels.

Abstract: A driving mechanism for a powered hammer having a motor and a tool holder includes a ram mounted for reciprocation in a guide tube section. The ram has a radially outwardly projecting sealing portion and an outer circumferential surface that defines a helically shaped vent channel running from a front end portion of the circumferential surface to a rear end portion of the circumferential surface and being interrupted by the sealing portion. A piston is driven in reciprocating motion of the motor such that an air cushion is generated in a space between the ram and the piston to cause an impact on the tool bit by movement of the ram towards the tool bit. The space between the ram and the piston is temporarily connected with ambient air through the helical vent channel and a recess in the wall of the guide tube section after causing the impact on the tool bit.

Abstract: A piston has a pair of diametrically opposite skirt portions with convex outer surfaces. Each skirt portion has opposite side edges extending substantially parallel to a central axis of the piston to a free end. The skirt portions each have a recessed slot extending radially into the convex outer surface to a recessed surface. The recessed surface extends fully across the convex outer surface to the side edges and separates an upper band section of the convex outer surface from a lower band section of the convex outer surface.

Abstract: A compressor for an air conditioning system comprises a piston and a pin. The piston comprises an aperture forming a piston bearing surface and a lubrication port in communication with the aperture. The pin comprises a pin bearing surface and the pin is received within the aperture to form an interface between the pin bearing surface and the piston bearing surface. In another embodiment, a method of lubricating within a compressor comprises rotating a crankshaft within a crankcase, introducing lubricant into the crankcase; and contacting the lubricant with a portion of a pin disposed within a piston via a lubrication port in the piston. In yet another embodiment, a piston for a compressor comprises an aperture forming a piston bearing surface and a lubrication port in communication with the aperture.

Abstract: A piston (20) includes a piston skirt (30) extending along a longitudinal axis (L) and having a pair of convex outer surfaces (42) facing opposite one another. Each of the outer surfaces (42) include an oil reservoir (44) above the pin bore axis (P) and an oil recess (46) below the pin bore axis (P) and spaced from the oil reservoir (44) by an intervening oil spreading area (48). The oil reservoir (44) and oil recess (46) each include a bottom (50) extending over an area of the outer surface (42) and surrounded by ramped side walls (52). The oil recess (46) and oil reservoir (44) include radiused corners (54) at a transition between the outer surface (42) and at the bottoms (50), so that the oil reservoir (44), oil recess (46), and outer surface (42) are free of sharp edges.

Abstract: A piston apparatus which configures an air bearing by introducing a compressed working media into an inside of a piston, and ejecting the working media from plural holes arranged on a circumferential portion of the piston into a clearance between the piston and the cylinder, which prevents a back-flow of the working media in the piston to a working space, and which readily secures reliability and longevity is provided.

Abstract: A reciprocating compressor is disclosed. The compressor includes a piston mounted to reciprocate inside of a cylinder that draws a working fluid into an inside of the cylinder, compressing, and discharging the working fluid to an outside of the cylinder, a connecting rod connected between a crank shaft and the piston that converts a rotating movement of the crank shaft into reciprocating movement of the piston, a piston pin arranged to pass the cylinder and one end of the connecting rod at the same time, and an oil passage formed to make a clearance between an inside surface of the one end of the connecting rod and an outside surface of the piston pin in communication with an outside of the clearance.

Abstract: A hydrostatic displacement unit having pistons which are composed at least partially of a high-grade aluminum material which are made of one piece or a composite to reduce wear.

Abstract: A high-pressure pump having a rotationally driven drive shaft and at least one pump element which has a pump piston driven at least indirectly in a reciprocating motion by the drive shaft which piston is guided in a cylinder bore and with its end remote from the drive shaft defines a pump work chamber. The pump piston is braced at least indirectly on the drive shaft. Extending through the pump piston is at least one line which discharges at the circumference of the pump piston in the cylinder bore spaced apart from the end of the pump piston that defines the pump work chamber and which leads toward the drive shaft to the region where the pump piston is braced.

Abstract: The invention relates to an axial piston machine, in particular, an air-conditioning compressor for motor vehicles, with at least one piston, an essentially cylindrical piston shaft and an enclosure, which encloses a tilt ring or a tilt disc and a piston slipper sliding on said tilt ring or said tilt disc, whereby the enclosure has spherical recesses for housing the piston slipper.

Abstract: A piston has a piston head that is provided with a field of rings and a piston shaft which is disposed thereupon. The piston shaft is equipped with supporting shaft wall sections and rear connecting walls which interconnect the shaft wall sections, have an arched shape, and are fitted with a bolt bore. An undercut free space is provided below the annular field in the area of the bolt bore in the region of the piston head. An arched zone is disposed in the interior of the piston at the transition from the bolt bore in the direction of the shaft wall session.

Abstract: A piston has a piston body with a pair of pin bosses having pin bores aligned along a central axis. The pin bores have bearing surfaces, wherein at least one recess extends axially across at least one of the bearing surfaces. A groove extends partially about the bearing surface circumference and is arranged in fluid communication with the recess. The recess and groove provide a lubrication feature to the pin bore, while the bearing surface has an uninterrupted portion for enhanced load carrying capacity.

Abstract: A syringe for syringe pumps or like instruments is disclosed, having a modified plunger disposed with a barrel wiper for enhancing seal life of the syringe. The syringe comprises a cylindrical barrel that is slideably engaged to a plunger via a seal. The syringe barrel wiper provides for enhanced seal life by extended controlled lubrication to inhibit debris adherence and reduced seal friction by wiping the inside of the barrel to remove debris buildup and egress of debris. The wiper comprises a lubricant-permeated porous polymer material shaped as a cylindrical tubular member.

Abstract: A piston for internal combustion engine, compressor or the like, includes a piston ring, a piston skirt having a piston skirt wall. One or more lubricant channels and reservoirs are provided on an outer surface of the piston skirt. Lubricant is conducted to an outer surface of a piston skirt of a piston through the lubricant channels which are communicating an inner surface of the piston skirt with the outer surface thereof. The lubricant is able to be reserved in the lubricant reservoirs provided on the outer surface of the piston skirt to maintain lubrication between the piston skirt and cylinder wall so as to reduce a friction between the cylinder and the piston skirt, reduce loss of power due to friction and heat, improve the output power, reduce the fuel consuming, noise and exhaust, and achieve fuel saving and environment protection.

Abstract: Briefly, the invention comprises a vibrator with an on-demand start-up system, that inhibits fouling the atmosphere, with one embodiment of the invention including an integral non-fouling start-up system wherein at least one of the bearing surfaces contains a surface adhered lubricant so as to provide an on-demand static start-up system and in another embodiment the on-demand start-up system is a dynamic system that can unbalance the differential forces on the piston therein to ensure that the vibrator will begin vibrating “on-demand”. Thus, two types of start-up systems are available one an on-demand static start-up system and the other an on-demand dynamic start-up system with either of the systems can be used alone or if desired in combination to provide redundant start-up systems.

Abstract: A piston includes a cylindrical body having a neck formed on an outer periphery of the cylindrical body so as to form a first annular disk and a second annular connecting to the first annular disk via the neck, multiple through holes defined through the second annular disk to communicate with a first space among the second annular disk, the neck and the first annular disk, an annular recess defined in an outer periphery of the second annular disk and multiple slits defined through a bottom face defining the annular recess to communicate with a second space below the first annular disk after passing through the neck.

Abstract: A sample handling tool includes a body having at least one plunger associated with a channel and arranged for axial movement within the channel. A seal is provided in the channel and sealingly engaged with a contact surface. The contact surface may include a surface feature, such that when contact surface moves, the seal and surface feature come into at least partial contact with one another. The seal may include an elastomeric member, such as an O-ring or X-ring, and the contact surface may be formed from any suitable material, including ceramic. The surface feature may take on a variety of forms including any suitable texture, surface porosity or include one or more grooves, holes, recesses, indentations, bumps, protrusions, etc., or a combination thereof.

Abstract: The present invention intends to provide a slide member with increasing an abrasion resistance and an adherence, a friction coefficient is further decreased. A part of the base member surface of the slide member is provided with a streak so that a surface roughness thereof by a ten-point height of roughness profile is 8 to 18 ?mRz. A dry coat lubricant has polyamideimide resin, at least one kind of a layer improve agent selected from epoxysilane and epoxy resin, and at least one kind of hard particles selected from a silicon nitride and an alumina. Such construction can not only increase the abrasion resistance and the adherence of the slide member, but can decrease friction coefficient of the slide member.

Abstract: A method of forming a low-friction, helically ridged skirt surface of an engine piston comprises cutting a continuous groove in a piston body rotating about axis so that adjacent groove turns intersect as ridges and carry lubricating oil which forms a film on the ridged surface. The groove is cut by way of a diamond tool tip traversing along the axis. Whereas in a known, standard finish, the ridges have sharp peaks that can rupture the oil film, the tool is here modified to include a planing tip fixed spatially with respect to the tip so that after formation each ridge is planed flat to provide a plateau between groove turns that exerts less film rupturing pressure against a cylinder wall while defining a uniformly flat outer surface for the piston. The cutting may vary the piston diameter toward the ends of the body to effect barreling in which the relationship between plateau width and groove depth vary.

Abstract: Disclosed is a closed cavity piston made from a metal injection molding process. The piston has an elongated cylindrical body with a first end that is adapted to receive a slipper. The piston also has at least one hollow compartment and a hollow stem that transports hydraulic fluid. After the metal injection molding process an end cap having a central opening is sinterbonded to the second end of the body. The central opening aligns with the hollow stem to provide a fluid outlet.

Abstract: A piston for a compressor for use in hermetically encapsulated small-type refrigerating machines, with a cylinder-jacket-like sealing and guide surface section (1a, 2) as well as at least two substantially bridge- and cylinder-jacket-sector-like sealing and guide surface sections (6) of the piston skirt allowing the guidance of the piston in the cylinder as well as sealing the crankcase relative to the sealing or compression chamber and other sections of the piston skirt comprising a recess (3, 7).

Abstract: The invention relates to a radial piston pump for generating high fuel pressure in fuel injection systems of internal combustion engines, in particular in a common rail injection system, having a driveshaft, supported in a housing, that has an eccentrically embodied shaft portion which cooperates with preferably a plurality of pistons capable of reciprocating radially, relative to the driveshaft, in a respective element bore, in order to aspirate fuel and subject it to high pressure in a high-pressure region. In order to increase the efficiency and lengthen the service life, in the outer jacket face (3) of the pistons and/or the inner jacket face of the element bore, a structure in the ?m range is formed.

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: A sliding structure for a reciprocating internal combustion engine, including sliding elements relatively slidable via lubricating oil therebetween, the sliding elements including sliding surfaces opposed to each other and lubricated with a laminar flow of the lubricating oil. The sliding surfaces each have base surfaces and microscopic dimples or grooves which are so constructed as to prevent reduction of flow resistance to the lubricating oil passing through a clearance between the sliding surfaces and assure a lubricating oil film thickness required for reducing friction loss between the sliding elements.

Abstract: A piston for a compressor for use in hermetically encapsulated small-type refrigerating machines, with a cylinder-jacket-like sealing and guide surface section (1a, 2) as well as at least two substantially bridge- and cylinder-jacket-sector-like sealing and guide surface sections (6) of the piston skirt allowing the guidance of the piston in the cylinder as well as sealing the crankcase relative to the sealing or compression chamber and other sections of the piston skirt comprising a recess (3,7).

Abstract: The outer diameter &PHgr;d1 of a top face-side end portion 35 of pistons 7 is made slightly smaller than the outer diameter &PHgr;d0 of a hollow cylindrical portion 36 of the pistons 7 other than the top face-side end portion 35. Thus, the tilt load of a top face-side portion of the piston 7 is divided and distributed, and at the same time, lubricating oil is held at the top face-side end portion 35 of the piston 7.

Abstract: A method of manufacturing male bimetal slippers includes the steps of forming a stem having opposite first and second ends; rigidly affixing a ball on the first end of the stem to form a male slipper body; and capacitance discharge welding a wear pad to the second end of the stem. To manufacture female bimetal slippers the method includes forming a slipper body of a first material, the body having opposite first and second ends, the first end having a ball socket formed therein; and capacitance discharge welding a wear pad of a second material to the second end of the body.