Abstract: A piston assembly includes first and second pistons, a transition arm coupled to each of the pistons, and a rotating member rotating in a first direction about a first axis. The transition arm includes a drive member coupled to the rotating member off-axis of the rotating member. A first counterbalance is mounted to rotate in the first direction, and a second counterbalance is mounted to rotate in a second direction opposite the first direction. The second counterbalance rotates about a second axis offset and parallel to the first axis. Alternatively, the second counterbalance rotates about the first axis. A method of counterbalancing a piston assembly includes mounting a first counterbalance to the piston assembly to rotate in the first direction, and mounting a second counterbalance to the piston assembly to rotate in the second direction.

Abstract: According to an embodiment of the present invention, a ring groove 11 for a two-piece oil ring 10, of a piston 20, is provided that has a ring body 5 equipped with a coil expander 6, where the ring body 5 has an upper outer surface and a lower outer surface, both orthogonal to the axial direction of the piston 20. The ring groove 11 has an upper inner surface 13 and a lower inner surface 14, both orthogonal to the axial direction of the piston 20; a radially inward-most, bottom surface 12 connecting the upper and lower inner surfaces 13, 14; and oil drain holes 18 each having an opening 19 thereof located on the bottom surface 12. The ring groove 11 has an axial width slightly greater than the width of the two-piece oil ring 10.

Abstract: Swash plate type compressor including a cylinder block having cylinder bores arranged along a circle, a drive shaft aligned with the circle, a swash plate rotated with the drive shaft, and single-headed pistons each including a head portion engaging the cylinder bore, and a neck portion engaging the swash plate, and wherein each piston is reciprocated by the swash plate rotated by the drive shaft, and the head portion includes a circular body portion, and an outer sliding portion and an inner sliding portion which are disposed between the body portion and the neck portion and which slidably engage respective circumferential portions of the cylinder bore which correspond to respective radially outer and inner portions of the cylinder block. Length from the end face of the body portion to the remote end of the inner sliding portion is larger than the corresponding length of the outer sliding portion.

Abstract: The invention relates to a high-pressure piston cylinder unit, especially an injection pump or an injection valve for an internal combustion engine, and to a method for producing one such high-pressure piston cylinder unit. The high-pressure piston cylinder unit has a piston which is guided inside a cylinder bore and which is coupled to an actuating element. The piston is subjected to a high pressure differential. According to the invention, fine grooves which run very close to one another are configured in at least one part of the guiding surface of the piston. The grooves ensure hydraulic pressure compensation on the periphery of the guiding surface, thus reducing wear, and prevent leakage in a longitudinal guiding direction.

Abstract: An apparatus for moving an operating element has a guide surface along which the operating element may be guided. A drive means provides a driving pulse exerted on the operating element for the movement of the operating element along the guide surface. A gap between the guide surface and the outer surface of the operating element is filled by a layer of a material that acts as an adhesive layer when the operating element is at rest and as a lubricating layer when the operating element is in motion. The outside of the operating element may have a conical profile and the guide surface may have a cylindrical profile, with the gap between the guide surface and the outer surface of the operating element becoming progressively larger in the direction of movement of the operating element. The layer of material in the gap may be a dry or solid lubricant, comprising material such as MoS2 or polytetrafluoroethylene.

Abstract: To enable economical production of a piston for a piston pump, the piston is made from a tubular deformed part and a closure plug, which is press-fitted with a protrusion into the deformed part. The piston has the advantage that the piston can be made without metal cutting in the form of deformed parts, for instance by extrusion, and hence can be produced quickly and economically.

Abstract: A part of a piston is composed of a metal matrix composite. The metal matrix composite is composed of a matrix of a light metal alloy and reinforcements formed of metallic fibers mixed in the matrix. The reinforcements are formed of an alloy that consists mainly of Fe and Cr and contains Al and/or Si. The Cr content and the Al and/or Si content of the reinforcements range from 5 to 30% and from 3 to 10%, respectively. The fiber diameter of the reinforcements ranges from &phgr;20 &mgr;m to &phgr;100 &mgr;m. The reinforcements are formed by the melt extraction method and have irregular peripheral surfaces. Solution-treatment of the metal matrix composite is carried out within a temperature range from 470° C. to 500° C. such that formation of intermetallic compounds is restrained.

Abstract: The present invention relates to a hydraulic piston and a process for its surface treatment in order to improve above all the wear resistance and corrosion resistance at the surface of the piston. As a favorable manufacturing process for the surface treatment of an above-mentioned hydraulic piston, a multistage process is disclosed which arranges a nitrocarburization with a subsequent oxidation and a following mechanical solidification of the oxidized surface for the piston. As a result, several superposed layers—layer of oxide, connecting layer, diffusion layer—develop at the piston surface which exhibit the desired qualities.

Abstract: In hydraulically actuated fuel injectors that utilize lubricating oil as the actuation fluid, various components within the injector body must move relatively short distances at high rates of speed in a wetted oil environment. When the oil is at a relatively low temperature, its relatively high viscosity coupled with relatively small size of these components can cause stiction problems to occur. Stiction occurs where the moveable component comes in contact with the body when it rests against its stop. The highly viscous oil can tend to cause the component to resist breaking free of its stop surface such that the fuel injector may be inhibited in performing adequately, especially during cold start conditions. These potential stiction problems are reduced by including a raised surface feature on one or both of the component and body in order to reduce the potential contact surface area.

Abstract: The object of the present invention is to propose a compressor in which rotation of a piston is prevented without affecting a big unbalanced load to the piston and the manufacture of the piston is simplified. The compressor comprises a housing having a cylinder bore therein, a drive shaft, a swash plate as a cam plate and a piston including a head portion and a neck portion. The housing and the piston are made of metal such as aluminium or an aluminium alloy. A rotation preventing member formed separately from the piston is mounted on the neck portion of the piston. The rotation preventing member is composed of a pair of rotation preventing portions, an abutting portion and a pair of caulking portions to mount to the neck portion. Those are made of metallic material such as iron series and formed in one body. The rotation preventing portion prevents the piston from rotating, cooperating with the contacting portion formed on the inner wall of the housing.

Abstract: A piston for a swash plate type compressor including a head portion which includes a cylindrical body portion whose open end is closed by a closure member, and an engaging portion which is formed integrally with the head portion on the side remote from the open end and which engages a swash plate of the compressor, wherein: the body portion includes a hollow cylindrical section whose inner circumferential surface is provided with a plurality of axially extending reinforcing projections, each of which protrudes from the inner circumferential surface in a radially inward direction of the hollow cylindrical section and which extends in a direction parallel to a centerline of the hollow cylindrical section over a substantially entire axial length thereof, the closure member being fixed to the body portion such that the closure member is held in abutting contact with an end face of each of the reinforcing projections on the side of the open end of the body portion.

Abstract: A hydraulic power assist steering system (10) for a vehicle having steerable wheels comprises a housing (14) and a rack (16). The system also comprises a fluid motor (20) for moving the rack (16). The fluid motor (20) includes a piston (10) fixedly connected to the rack (16) and a pump (36). The piston (10) has first and second opposite end faces (82, 84) against which hydraulic fluid is directed by the pump (36) to effect movement of the piston (10), and thereby the rack (16), relative to the housing (14). The piston (10) has a wall (60) including a first end portion (64) connected with the rack (16) at a first axial location along the rack, a second end portion (66) connected with the rack at a second axial location along the rack, and a central portion (62) extending between and interconnecting the first and second end portions of the wall. The central portion (62) of the wall (60) has an outer peripheral groove (70) for receiving a seal ring (86) for engagement with the housing (14).

Abstract: The present invention provides a piston type compressor in which vibration and noise due to interference between the piston and the cam plate can be suppressed by preventing the rotation of the piston, and at the same time, it is possible to improve the productivity and accomplish the cost down. According to the present invention, the piston type compressor comprises a housing including a crank chamber and a cylinder block. A cylinder bore is formed in the cylinder block. A piston is accommodated in the cylinder bore so as to reciprocate. The piston is operatively connected to the cam plate. The piston reciprocates accompanying with rotation of the drive shaft so that drawing and discharging of a refrigerant is performed. A rotation preventing portion is formed on the piston, and a groove facing the rotation preventing portion so as to have clearance is formed on an inner circumferential surface of the crank chamber.

Abstract: The invention relates to a piston pump, which is intended for use as a return pump for a slip-controlled hydraulic vehicle brake system. To simplify the manufacture of a piston of the piston pump, the piston includes a thin sleeve.

Abstract: A piston for a swash plate type compressor, including a head portion slidably fitted in a cylinder bore in a cylinder block of the compressor, a neck portion slidably engaging a swash plate of the compressor, and a connecting portion connecting the head and neck portions, wherein the head portion comprises a circular body portion, and an inner sliding projection extending toward the neck portion from a radially inner circumferential part of the body portion which corresponds to a radially inner portion of the cylinder block. The inner sliding projection has a sliding surface for sliding contact with an inner circumferential surface of the cylinder bore. The sliding surface is symmetrical with respect to a plane including centerlines of the piston and the cylinder block. The connecting portion connects the inner sliding projection and the neck portion.

Abstract: A simplified piston pump which is featured in that the number of components for the assembling thereof can be minimized, that the assembling thereof can be simplified, and low in manufacturing cost thereof. This simplified piston pump comprises; a cylinder having at least one protrusion formed on the inner surface of a proximal end portion of said cylinder for preventing the piston from slipping out; and a piston shaft having a structure wherein the outer surface of the piston shaft is contacted with the inner surface of the cylinder to prevent the decentering of the piston shaft and wherein a groove is formed thereon to ensure the reciprocative movement of the piston.

Abstract: A hollow head portion of the piston is provided with a bottomed cylindrical portion and a cap closing an opening of the bottomed cylindrical portion. The cap is in the form of bottomed cylinder including a bottom wall, a cylindrical large diameter portion and a cylindrical small diameter portion. An outer circumferential surface of the small diameter portion is fitted to an inner circumferential surface of the cylinder portion of the bottomed cylindrical portion so that end faces are contacted with each other, and then these end faces are connected to each other by welding. A cap length, which is an axial distance from an apex surface of the cap to the end face thereof is set to be larger than a thickness of the bottom wall so that the welded portion is located far from a boundary portion between the bottom wall and the large diameter portion.

Abstract: A hollow piston has an end wall that receives the pressure of a cylinder bore of a compressor. Several reinforcing ribs are formed on the inner end face of the end wall. The ribs extend radially from the axis of the piston. Therefore, the piston is light and strong.

Abstract: A piston for use in the cylinder block of a hydraulic power unit. The piston has an elongated cylindrical body and one end terminating in a spherical surface. The piston is composed of a body and insert which are made from different materials, preferably metallic materials, and joined together. The piston body takes the form of a solid cylinder or a hollow cylindrical tube. The spherical surface takes the form of an internal spherical socket or an external spherical ball. The insert takes an elongated or abbreviated form providing for both open cavity and closed cavity piston configurations. The piston includes a conduit which traverses the body and insert, providing a path for pressurized fluid.

Abstract: A compressor comprises a piston having a piston head and an engaging portion, said piston head being inserted into a cylinder bore, said engaging portion having a piston guide and a shoe seat in which a shoe is incorporated, wherein said shoe is engaged with a swash plate. The piston reciprocates in correspondence to rotation of the swash plate and the piston head compressing a refrigerant by the reciprocal movement. The piston guide protrudes outward from the surface of the piston head, extending over said shoe seat, being formed with dimensions exceeding the corresponding shoe seat and being caused to reciprocate along the inner wall surface of said housing in line with reciprocation of said piston.

Abstract: A compressor includes a piston reciprocating in a cylinder bore. The piston draws refrigerant into and discharges refrigerant from a compression chamber, which is formed between the piston and a valve plate. The valve plate has a discharge port connecting the compression chamber to the discharge chamber. A guide passage facilitates the flow of the refrigerant from the compression chamber to the discharge port. The guide passage is defined in the compression chamber when the piston is located at the top dead center position. This decreases pressure losses that would otherwise occur when the piston is near the top dead center position.

Abstract: A method of producing a hollow piston for a compressor, the piston including a head portion which is slidably fitted in a cylinder bore of the compressor, and an engaging portion which engages a reciprocating drive device of the compressor for reciprocating the piston, at least the head portion of the piston being hollow, the method comprising a step of preparing at least one piston blank by forging, which piston blank includes an engaging-portion-forming section which provides the engaging portion of the piston, and a head-portion-forming section which provides at least a part of the head portion of the piston, the at least one piston blank being prepared by a two-axes forging process which uses a forging die assembly including a set of two first dies which are movable relative to each other along a first axis which is one of two mutually perpendicular axes, and at least one second die which is movable along a second axis which is the other of the two mutually perpendicular axes.

Abstract: A fuel injection pump for high pressure injecting gasoline, fuel whose main component is gasoline or light oil having a sulfur content of 0.05% by weight or less by a reciprocation of a piston sliding relative to a cylinder, wherein at least a sliding surface of the piston to slide on the cylinder is made of ceramic and the surface roughness thereof, expressed in ten-point mean surface roughness Rz, is 0.05-0.4 &mgr;m in a direction perpendicular to the sliding direction and 0.2-0.6 &mgr;m in a direction parallel to the sliding direction while the surface roughness expressed in the ten-point mean surface roughness Rz of a cylinder sliding surface corresponding thereto is 0.2-0.8 &mgr;m in a direction parallel to the sliding direction. By using the above combination of piston and cylinder, the wear resistance of the piston and cylinder is improved, the durability thereof is improved and the production cost can be largely reduced.

Abstract: A piston, adapted for use in a swash plate type of air conditioning compressor including a generally cylindrical cylinder block provided with at least one cylinder bore, in which the piston is reciprocally disposed. The piston includes a cylindrical body with a head portion, a bridge portion extending from the body and having a recess, and a pair of shoe pockets formed in opposed walls defined in the recess. Each of the shoe pockets includes an entrance and an apex, and a lower edge portion of the body is positioned at an adjoining portion between the body and the bridge portion extending to a place between the entrance and the apex of the shoe pocket adjacent to the body.

Abstract: A reciprocating pump or compressor has an alignment adapter for providing a self-aligning piston rod. The alignment adapter and a clamp couple the piston rod to a crosshead extension rod. The alignment adapter provides compensation for misalignment of the longitudinal axis of the crosshead extension rod with the longitudinal axis of the piston rod. The alignment adapter has a hemispherical cavity, and the piston rod has a hemispherical projection that matingly fits within the hemispherical cavity. A split ring is received in a groove in the piston rod, and the piston rod and the split ring are received in the cavity in the alignment adapter for use in coupling the piston rod to the alignment adapter. A piston head has a hemispherical cavity for receiving a hemispherical projection on a piston rod. The piston head has a longitudinal midpoint, and the hemispherical projection has a focal point for a radius of curvature.

Abstract: This invention relates to rotary piston machines with a positive displacement principle, pressure-tight work chambers and a strong piston actuating mechanism without power transmitting bearings. A piston rotor is rotationally coupled via its pistons or plungers, which reciprocatingly move in the cylinders of a cylinder rotor. Both axial and radial machines are included having a short stroke motion, but only in a co-rotating system. No oscillating mass power exists. This new piston actuating concept is applicable for all machines having at least one rotating pair of piston and cylinder. On top of the wide variety is an axial piston machine with a self-aligning pulling piston actuating mechanism and a quasi complete hydrostatic pressure balance of all movable parts including an outgoing shaft.

Abstract: A piston and piston ring assembly has a compression ring and a compression ring groove configured to allow proper mating between the two following thermal expansion. The groove is provided with a substantially horizontal lower face. The ring has a bottom surface that is contoured to provide a cross-sectional angle that substantially matches the anticipated deflection of the lower face caused by thermal expansion. Thus, when the piston expands due to temperature changes associated with operating the internal combustion engine, the lower face deflects away from the combustion chamber. The deflection is absorbed by the pre-contoured bottom surface of the ring. Thus, localized high points between the piston ring and the piston ring groove are reduced and the friction originating at such locations is also reduced. Accordingly, the ring and the groove experience reduced friction and reduced wear while the sealing function of the compression ring is enhanced.

Abstract: For locking against rotation a piston on a piston rod, the piston having a peripheral groove and at least one radial through-hole to be positioned over a notch, a locking clip with a first straight end part and a curved part has a first end part extending through the radial hole in the piston and a part of the curved part of the locking clip rests in the peripheral groove when in a piston-locking position.

Abstract: A piston-type compressor has seven cylinder bores formed in a cylinder block which is formed in a compressor housing. A piston is slidably disposed within each of the cylinder bores. Each of the pistons includes a cylindrical main body and an engaging portion axially extending from the cylindrical body. A drive shaft is rotatably supported in the cylinder block. A bearing couples the plate to each of the pistons, so that the pistons reciprocate within the cylinder bores upon rotation of the plate which is tiltably connected to the drive shaft. A recessed portion is formed in an interior of the cylindrical body of each piston so that the cylindrical body forms a C-shaped cross-section perpendicular to longitudinal axis of the piston. Therefore, the configuration obtains lightweight pistons while simultaneously maintaining the efficiency of the compressor.

Abstract: This invention relates to a piston for reciprocating and simultaneously rotating through a predetermined length of movement within a piston bore having a piston bore surface, and a method for reducing wear on a piston bore surface operatively associated with a piston which is subject to cocking forces. The piston includes a means on its extreme portion for providing continuous, tangential cooperation with the piston bore surface within the predetermined length of piston movement to reduce wear on the piston bore surface.

Abstract: A novel reciprocating pump for cryogenic fluids. The pump has a cylinder sleeve, head, intake valve, discharge valve, and a reciprocating piston including a mechanical spring energized seal having a generally U-shaped jacket and a helical spring in the bight of the U.

Abstract: A piston-cylinder unit for a hydraulic system, especially for the actuation of clutches in motor vehicles, comprises a housing with an axially stepped bore hole in which a piston fastened to a tappet is guided so as to be axially displaceable. The piston displaces a fluid in the cylinder of the housing by its front end. The cylinder includes at least one pressure line connector, a connection to a fluid chamber, and at least one cup which is sealingly arranged in the housing relative to the outer surface of the piston. Both the housing and the piston comprise assemblies made of a plurality of parts. The assemblies are constructed by inserting the plurality of parts in order into a larger part and press fitting them in place.

Abstract: A piston pump for delivering hydraulic fluid for ABS brake systems having at least one pump piston. The pump piston is driven to execute an axial stroke motion and which, with a sliding face embodied on its circumference, slides against the inner wall of a guide bore in order to assure a favorable sliding friction between the pump piston and the guide bore for the purpose of noise reduction and to achieve longer service lives for the seal. Viewed in the longitudinal section of the pump piston, the slide face is embodied as wavy, wherein wave crests and wave troughs follow one another in succession in the longitudinal direction of the pump piston.

Abstract: Disclosed is a piston having a cylindrical body made from a thermosetting molding compound. The body has a central well and a molded-on metal cap having sides that extend downward over the exterior of the body and into the well. There is insulation under and in contact with the metal cap.

Abstract: There is described a piston for an axial piston machine with which the skirt surface (12) of the piston shaft (15) has, at its forward end region (Y) which transforms into the piston end face (11) and/or at its rear end region (X) lying towards the piston head, a bevel (16; 18; 19; 21) with continuously varied radiuses of curvature.

Abstract: A piston for use in a compressor is disclosed. The piston has a head for compressing gas and a skirt connected to a swash plate. A first seal and a second seal, which always contact a cylinder bore, are defined on the head. An annular groove is formed between the first and second seals. Lateral forces acting on the piston are received by the first and second seals. A space is formed in the piston to open to the side of the piston between the second seal and the skirt. This reduces the weight of the piston and stabilizes the movement of the piston.

Abstract: A three-dimensional piston molding is fabricated from a mixture of chopped, carbon tow filaments of variable length, which are prepregged with carbonaceous organic resins and/or pitches and molded by conventional molding processes into a near net shape, to form a carbon-fiber reinforced organic-matrix composite part. Continuous reinforcement in the form of carbon-carbon composite tapes or pieces of fabric can be also laid in the mold before or during the charging of the mold with the chopped-fiber mixture, to enhance the strength in the crown and wrist-pin areas. The molded chopped-fiber reinforced organic-matrix composite parts are then pyrolized in an inert atmosphere, to convert the organic matrix materials to carbon. These pyrolized parts are then densified by reimpregnation with resins or pitches, which are subsequently carbonized. Densification is also accomplished by direct infiltration with carbon by vapor deposition processes.

Abstract: In space exploration, an attitude control engine or a thruster may have an extended period, such as years, of inactivity prior to being required to complete a desired mission. The fuel for this mission is contained in a fuel tank for the same extended period of time and tends to corrode elastomeric components. To isolate the fuel from elastomeric components during the storage period, the fuel tank has a metallic shear seal. When actuated, a piston ruptures the shear seal and delivers the fuel to a power plant. A shear seal that is unitary with the inner walls of the fuel tank eliminates the need for an interfacial weld that may constitute a shear seal failure site.

Abstract: A piston type compressor comprises a compressor housing enclosing a crank chamber, suction chamber, and a discharge chamber therein. A plurality of pistons are slidably disposed within each of cylinders formed in a cylinder block. Each of the pistons includes a piston head, a piston end, a main cylindrical body and an engaging portion at the piston end axially extending from the cylindrical body. A first aperture is formed in the cylindrical body of the piston, so that the first aperture is near the piston head of the piston. A second aperture is formed in the cylindrical body of the piston so that the second aperture is near the piston end of the piston. The first aperture is positioned within the cylinder bore when the piston reciprocates in the cylinder bore. As a result, the piston type compressor of the present invention has a light weight piston which simultaneously reduces abrasion between the piston and the cylinder bore and reduces noise and vibration.

Abstract: In the embodiment shown, the body is formed of cast aluminum, and is devoid of clean-out holes in the upper and bottom ends thereof. Instead, the clean-out holes are formed in the outer, annular wall, through an annular recess formed in the outer wall, To close off the clean-out holes, a steel band is nested in the recess, in circumscription of the body. Further, the steel band has grooves formed therein in which to accommodate piston rings.

Abstract: A percussion tool comprises a cylinder 3 communicated to a pressure accumulating chamber 16 storing pressurized air therein, and a piston 4 slidable in the cylinder 3 when pressurized air is introduced into the cylinder 3 from the pressure accumulating chamber 16 and pressure of the introduced air is applied on the piston 4. A circular groove 6 is recessed on a peripheral surface of the piston 4, the peripheral surface adjacently facing to an inside wall of the cylinder 3. A piston ring 10 is accommodated in the circular groove 6, so as to provide a hermetical sealing between the piston 4 and the cylinder 3. And, a ring bumper 11 made of resilient member is provided in the circular groove 6 adjacent to the piston ring 10 in a sliding direction of the piston 4.

Abstract: A piston-type compressor has at least two cylinders formed in a cylinder block which is formed in a compressor housing. A piston is slidably disposed within each of the cylinders. Each of the pistons includes a cylindrical main body and an engaging portion axially extending from the cylindrical body. A drive shaft is rotatably supported in the cylinder block. A bearing couples the plate to each of the pistons, so that the pistons reciprocate within the cylinder bores upon rotation of the plate which is tiltably connected to the drive shaft. The piston includes a first aperture formed in a periphery surface of cylindrical body thereof; a second aperture formed in an interior the cylindrical body thereof, so that the second aperture communicates with the first aperture; and a cover plate member secured to the one axial end thereof for covering the second aperture. Therefore, the configuration obtains lightweight pistons while simultaneously preventing reducing the efficiency of the compressor.

Abstract: Apparatus and method for joining a piston in a precise leak proof junction on a rod utilizes an axial longitudinally elongated reservoir (A) in a bore within the piston which serves as a receptacle for a bonding agent (B), an annular groove (C) in the piston rod serves to position an O-ring member (D) serving as a support for the piston and as a closure on one end of the reservoir.

Abstract: In an inner cam type injection pump, the side surface of the protruding portion of each of the plungers facing the compression space is formed in a projecting shape in the area where the plunger changes from the base end side into the front end. Specific forms of the projection include a structure constituted with slanted surfaces over a plurality of stages with different inclinations relative to the axis of the plunger, an arc form and a structure provided with a overhanging portion formed on the side surface of the protruding portion, which does not overhang the base end, projecting out from the side surface. This will prevent collision at the shoulder portion of the plunger and, consequently, prevent the deformation at the shoulder portion and ensures that plungers will not have sliding failures or become seized. Even when plungers collide, the sliding of the plungers will not be affected, ensuring that plungers do not have sliding failures or become seized.

Abstract: An improved fluid section for piston type paint pumps having the piston made from unplated stainless steel and wherein the seal is a multiple lip type formed of ultra-high molecular weight polyethylene and the seal further includes one or more U-shaped internal stainless steel springs.

Abstract: A wobble piston usable in a cylinder comprising one or both of the confronting surfaces of wobble piston head or valve plate being convexly curved in the plane of the wobble motion and being straight in a plane that is transverse to the plane of the wobble motion.

Abstract: This invention relates to a piston and a method of manufacturing the same. The piston includes a substantially cylindrical member having a first end and a second end. The cylindrical member includes an open cavity extending axially from the second end to adjacent the first end such that the second end has an inner annular surface defined by an inner diameter. The piston further includes a disk having a radially outer surface defined by an outer diameter fixedly secured to the second end of the cylindrical member. The outer diameter of the disk is substantially equal to the inner diameter of the inner annular surface of the second end of the cylindrical member. A circumferentially extending recessed area for receiving particles produced while fixedly securing the disk to the second end of the cylindrical member is provided on either the radially outer surface of the disk or the inner annular surface of the second end of the cylindrical member.

Abstract: A swash plate piston (20) of integral, one piece design has outer surface portions in contact with much of the total available inner surface of the cylinder bore (18), but with a basically hollow design that can be easily manufactured. Outer (36) and inner (38) semi cylindrical segments of the piston (20) extend axially back from a cylindrical head (32), but leave the center of the piston body entirely open and empty. A slanted wing member (40) extends out and down from the inner segment (38), into the outer segment (36), creating a four sided, frame like structure of superior strength. All of the outboard outer surfaces of the piston (20) lie on the same cylindrical envelope as the cylinder bore (18) itself, giving good, even support. However, none of the outer surfaces, outboard or inboard, present any concavities that would jeopardize the ability to form the piston (20) with only two forming elements that part in a straight line.

Abstract: A disc brake having a plurality of pistons with the same outer diameter fitted in a cylinder portion of a caliper on at least one side of a disc so that the pistons cause a pad to press against the disc. At least one of the pistons has a relatively large wall thickness so that it is different from the other pistons in pad pressing area, and its natural frequency falls outside the range of from 20 Hz to 20 kHz, thereby suppressing the generation of brake noise.

Abstract: A substantially flat abutting surface 20a is provided on an outer side of a carriage member 6 which is axially movable along the outer periphery of a cylinder tube 2, while a rail 4 with a substantially flat guide surface 4a is mounted between a pair of end covers closing the opposite axial ends of the cylinder tube. Rotational movements of the carriage member 6 are restricted by the rail 4 which is located on the outer side of the carriage 6.