Abstract: A two-part piston for an internal combustion engine consists of an upper part, a lower part and a circumferential, closed cooling channel radially on the outside and close to the piston crown. The channel is closed off, on its underside, by a cooling channel cover which is connected via a skirt connection with two skirt elements that lie opposite one another. In order to reduce the piston weight and nevertheless avoid secondary movements of the piston, circumferential recesses are provided in the region of the skirt elements, which are delimited by the cooling channel cover on the piston crown side and by the skirt connections on the skirt side. The skirt connections are connected with the radially inner region of the cooling channel cover on the piston crown side, and with the upper regions of the skirt elements on the skirt side.

Abstract: A piston (21; 104) to be mounted inside a cylindrical bore (46; 117) has a cylindrical surface (32; 114) provided with at least one axially extending deepening (31; 116) for accommodating a thermal distortion of the cylindrical bore (46; 117). Preferably, the piston is used in a piston valve as a valve control member or turbine as a variable nozzle control member.

Abstract: A piston for an internal combustion engine includes a piston head provided with an annular field, and a piston shaft arranged beneath the annular field. The piston shaft has shaft surfaces and a recess surface which is arranged around a bolt borehole and set back in relation to an outer diameter of the piston. At least one cavity is provided in the region of the lowest annular groove for oil flow in the direction of the recess surface during the movement of the piston and the at least one cavity is arranged outside an especially stressed region above the bolt borehole.

Abstract: Disclosed is a multipart, cooled piston for a combustion engine, comprising, in a radially outward direction, an annular cooling duct located on the bottom side that faces away from the piston head. The cooling duct is closed by a cooling duct cover which is embodied as a ring. The cooling duct cover is provided with a tongue in the radially inner zone. The tongue engages into a recess that is molded into the bottom piston part, thus preventing the cooling duct cover from rotating relative to the piston during assembly as well as during operation.

Abstract: Disclosed is a two-part piston (1) for a combustion engine comprising a combustion chamber (16) in the piston head (13). The piston (1) is composed of a basic member (5) and a top part (6) that is screwed to the basic member (5). In order for the combustion pressure to act substantially upon the basic member (5), which is provided with great mechanical stability and load-bearing capacity relative to the pressure prevailing in the combustion chamber, the bottom part of the combustion chamber (16) is molded into the basic member (5), the top part (6) is configured in an essentially annular manner, and the top part (6) enlarges the combustion chamber (16) at the piston head end while delimiting the same in a radially outward direction similar to a collar (19).

Abstract: A piston assembly is disclosed herein. The piston assembly is integrally formed and unitary and is centered on a central longitudinal axis. The piston assembly includes a head with ring belt having a plurality of ring grooves. The piston assembly also includes first and second skirts, each having a top edge and a bottom edge being radially narrower than the top edge. The skirts also include first and second side edges. The piston assembly also includes first and second pin bosses spaced radially inward from the ring belt to define a short-pin support arrangement. The pin bosses include respective first and second pin bores axially aligned on a pin bore axis perpendicular to the central longitudinal axis. The piston assembly also includes a plurality of panels, each extending between one of the pin bosses and one of the skirts.

Abstract: An engine piston is manufactured by assembling an outer shell, comprising a crown and tubular side wall in which a ring groove region and skirt are defined, with a plate-like mounting member and bonding them together by brazing or welding. The mounting member is located within the tubular side wall displaced axially from the crown and is bonded near, but displaced radially from, its centre to the crown and at its periphery to the side wall at the end of the ring groove region. The mounting member carries gudgeon pin boss means facing away from the crown. The outer shell is formed by extrusion or the like that permits minimal wall thickness and the bonded structure is of light weight but great strength and stiffness, particularly in the ring groove region. A combustion bowl formed in the crown facilitates bonding to the mounting member and defines with the mounting member an annular cooling chamber adjacent the ring groove region and crown.

Abstract: A piston for an internal combustion engine has an upper crown with a top and a bottom surface, and a lower crown with a top and a bottom surface. The upper crown and the lower crown are fixedly attached to each other using welds, with the bottom surface of the upper crown and the top surface of the lower crown forming a mating surface. The piston also has at least one centrally located air gap formed on the mating surface. The air gap is sealed to prevent substantial airflow into or out of the air gap.

Abstract: A piston for a two-cycle engine having a piston head and a piston wall in which are disposed wrist pin eyes. At least one undercut is formed between the underside of the piston head and the wrist pin eyes at a distance from the piston head. The undercut extends from the interior of the piston toward the piston wall. A respective thickened portion is provided in at least one region of the piston that is rotationally shifted about the longitudinal axis of the piston by 90° relative to one of the wrist pin eyes. The thickened portion is disposed at a distance below the piston head and extends into the interior of the piston.

Abstract: A piston assembly is described including a connecting rod and a piston head secured to the connecting rod and in operational communication with the connecting rod. The piston head has a circumferential groove extending inwardly from an exterior surface of the piston head. The piston head further has a compression mechanism aperture disposed proximate the groove. An oil ring expander is disposed generally within the groove. The expander includes a gap between a first expander end and a second expander end. The gap is proximate the compression mechanism aperture. At least one lever arm is in mechanical communication with the connecting rod. The at least one lever arm has a tab disposed between the first expander end and the second expander end.

Abstract: A number of embodiments of a piston may have a shape that provides enhanced piston guidance. In such embodiments, the piston shape may include an axial profile that is configured to provide certain thrust load characteristics.

Abstract: A number of embodiments of a piston may have a shape that provides enhanced piston guidance. In such embodiments, the piston shape may include an axial profile that is configured to provide certain thrust load characteristics.

Abstract: A compressor assembly having a piston with multiple cross sections. The compressor assembly, in one form thereof, includes a cylinder block defining a cavity. A piston is at least partially disposed in the cavity and reciprocates along a central axis of the cavity. The piston includes a first piston portion and a second piston portion. The first piston portion has a cross sectional configuration and area substantially similar to a first portion of the cavity and the second piston portion has a radially outer surface at least partially engageable with the sidewall of a second portion of the cavity. The second piston portion may also have a larger cross sectional area than the first portion of the piston which may be used to compress a refrigerant within the cavity.

Abstract: A piston for an internal combustion engine includes a crown part, a land part extending from the crown part, a skirt part adjoining the land part, and a linking boss protruding from a reverse surface of the crown part and forming a spherical joint with a small end of a connecting rod. The piston is divided into an upper piston part having the land part, and a lower piston part having the skirt part and a plurality of molded plate members formed by press-molding plates.

Abstract: A forged piston for an internal combustion engine formed from an aluminum alloy containing silicon in an amount of 6 to 25 mass %, includes an oil ring groove section (12) and a skirt section (13). The ratio (A/B) of the average size (A) of eutectic silicon grains contained in the oil ring groove section to the average size (B) of eutectic silicon grains contained in the frontal end portion (18) of the skirt section is at least 1.5. The average size (A) is at least 4 ?m. With the configuration such that the average size (B) is small and that the average size (A) is large, the skirt section exhibits excellent forgeability and the oil ring groove section exhibits reliable mechanical workability and improved wear resistance.

Abstract: By casting a preformed member composed of a fiber reinforced material into a base material of a piston, a pair of crown reinforcing portions corresponding to respective pin boss portions are formed on a crown portion, and the pair of crown reinforcing portions are connected to each other along the piston pin axis by a connecting portion. Thus, the strength of the piston is increased by the crown reinforcing portions, and also, heat distortion of the crown portion is inhibited since the crown reinforcing portions integrally connected to each other by the connecting portion are formed so as to serve as a rigid member extending along the piston pin axis.

Abstract: A combination of piston and piston ring includes a piston having a piston ring groove in which at least the groove portion of the piston is made of steel, a piston ring made of cast iron and fitted into the piston ring groove, and a hard coat film formed to at least an outer peripheral sliding surface of the piston ring.

Abstract: The invention relates to a cup-shaped hydraulic piston (10) made from rolled sheet metal, which comprises an open end (12), a side wall (16) with a cylindrical outer surface (18) and an inner surface (22), as well as a piston head (14). The side wall (16) at its outer surface (18) is provided with an annular groove (20) in a portion adjoining the open end (12). To ensure a lightweight style of construction combining high stability with ease of manufacture, the part of the inner surface (22) adjoining the open end (12) and extending axially over the annular groove (20) has a cylindrical shape, and the thickness of the side wall (16) decreases monotonically from the portion (24) of the inner surface (22) up to the piston head (14).

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: A light weight piston for an internal combustion engine is disclosed that minimizes the stresses found in a transition area between the piston head and the associated piston pin bosses while maintaining a flexible soft connection between the piston skirts and the piston head. The piston includes a pair of piston skirts having tapered edges. Flared connecting walls are provided such that the distance between the connecting walls is minimized adjacent a pair of piston pin bosses and the distance between the connecting walls is maximized adjacent a portion of the tapered edges. The connecting wall flares in a generally outward direction such that at least a portion of the inner surfaces of the connecting wall has a generally convex curvature.

Abstract: An engine piston has a crown portion generated about a longitudinal piston axis and, extending axially form the crown, a pair of gudgeon pin bosses defining a pin axis and spaced apart at opposite sides of an orthogonal thrust axis. A circumferentially discontinuous skirt defines lateral thrust and non-thrust bearing regions, respectively, centered on the thrust axis, each joined by convexly bowed reinforcement ribs to the bosses. The bearing region on the non-thrust side of the piston is circumferentially shorter than thrust region, reducing piston mass to one side of the piston, and the reinforcement ribs are offset in pin axis direction where they intersect the bosses. Mass reducing recesses are formed in the underside of the crown between the unskirted periphery reinforcement ribs and bosses, the offset ribs permitting the recesses to extend further and to permit greater reduction in mass.

Abstract: A forged piston for an internal combustion engine formed from an aluminum alloy containing silicon in an amount of 6 to 25 mass %, includes an oil ring groove section (12) and a skirt section (13). The ratio (A/B) of the average size (A) of eutectic silicon grains contained in the oil ring groove section to the average size (B) of eutectic silicon grains contained in the frontal end portion (18) of the skirt section is at least 1.5. The average size (A) is at least 4 &mgr;m. With the configuration such that the average size (B) is small and that the average size (A) is large, the skirt section exhibits excellent forgeability and the oil ring groove section exhibits reliable mechanical workability and improved wear resistance.

Abstract: A piston for an internal combustion engine which comprises a piston body, and a ring element, which together form a basic piston body. When the ring element is screwed onto the piston body, it forms a ring shaped cooling channel which is closed off in a direction of the pin bosses by a projection of the basic body. The projection is structured in the form of an elastically resilient cup spring which is deformed when the ring element is screwed onto the body. This deformation and counter stress, contributes to the strength of the screw connection.

Abstract: A wrist pin for a heavy-duty piston assembly has a body with an axis of rotation and a generally cylindrical outer surface. The outer surface is adapted for pivotal connection to both a pair of laterally spaced pin bores and a small end of a connecting rod generally between the pin bores. The outer surface has a surface roughness equal to or less than 0.10 &mgr;m. The outer surface has a Kurtosis value that is inversely proportional with the surface roughness such that a product of the Kurtosis value and the surface roughness is between about 0.30 &mgr;m to 0.60 &mgr;m. The outer surface has a skewness of about −1.0 to 0.0 and a lay angle relative to the axis of about 85 to 95 degrees.

Abstract: A method of forming a low-friction, helically ridged skirt surface of an engine piston 30 (FIG. 2(a)) comprises cutting a continuous groove (40) in a piston body rotating about axis (34) so that adjacent groove turns intersect as ridges (42) and carry lubricating oil which forms a film on the ridged surface. The groove (40) is cut by way of a diamond tool tip (60) traversing along the axis (34). Whereas in a known, standard finish the ridges (42) have sharp peaks that can rupture the oil film, the tool is here modified to include a planing tip (70) fixed spatially with respect to the tip (60) so that after formation each ridge is planed flat to provide a plateau (44) between groove turns that exerts less film rupturing pressure against a cylinder wall whilst defining a uniformly flat outer surface for the piston. The cuting may vary the piston diameter towards the ends of the body to effect barreling in which the relationship between plateau width and groove depth vary.

Abstract: An engine piston (10) has a crown portion (12) generated about a longitudinal piston axis (14) and, extending axially from the crown, a pair of gudgeon pin bosses (26, 28) defining a pin axis (30) and spaced apart at opposite sides of an orthogonal thrust axis (40). A circumferentially discontinuous skirt defines lateral thrust and non-thrust bearing regions (34, 36), respectively, centered on the thrust axis, each joined by convexly bowed reinforcement ribs (62, 64, 66, 68) to the bosses. The bearing region (36) on the nun-thrust side of the piston is circumferentially shorter than thrust region (34), reducing piston mass to one side of the piston, and the reinforcement ribs are offset in pin axis direction where thy intersect the bosses. Mass reducing recesses (106, 108) are formed in the underside of the crown between the unskirted periphery (37), reinforcement ribs and bosses, the offset ribs (66, 68) permitting the recesses to extend further as at (110) and permit greater reduction in mass.

Abstract: A light weight piston for an internal combustion engine is disclosed that minimizes the stresses found in a transition area between the piston head and the associated piston pin bosses while maintaining a flexible soft connection between the piston skirts and the piston head. The piston includes a pair of piston skirts having tapered edges. Flared connecting walls are provided such that the distance between the connecting walls is minimized adjacent a pair of piston pin bosses and the distance between the connecting walls is maximized adjacent a portion of the tapered edges. The connecting wall flares in a generally outward direction such that at least a portion of the inner surfaces of the connecting wall has a generally convex curvature.

Abstract: The present invention relates to a piston for a hydraulic pressure chamber, especially a piston bore of a spot-type disc brake, wherein the piston is configured as a bowl-shaped hollow cylinder that is open on one side and made from a metal blank of a constant wall thickness in a forming operation. The piston has a bottom to which hydraulic pressure is applicable and a piston wall which, at its open end, passes over into a rim that has a circular abutment surface. Especially in view of conventional cast pistons, an object of the present invention is related to providing a piston which permits being manufactured by means of a simple forming operation, which can be configured as light as possible and with low expenditure in material, without limiting the stress capacity of the piston.

Abstract: An engine piston (10) comprising a crown (12) and a tubular body portion (30) containing gudgeon pin bosses (46) and force transmitting regions (66) has the body portion forged, preferably of steel, as two or more circumferentially incomplete segments (1001, 1002) which extend about a longitudinal piston axis (14) and are joined into the tubular form by welding or the like. The segments are forged in a direction perpendicularly to the piston axis which permits the formation of regions of differing wall thickness along the tubular body length and mass saving recesses (70) between force transmitting struts (661) and (662) that are not possible with forging a unitary tubular body from one end.

Abstract: The invention relates to a built-up piston, comprising central screwing and a central cooling chamber. The aim of the invention is to reduce the flow resistance in the oil delivery area. To this end, means for transferring oil from the piston rod to the central cooling chamber are provided in the area of the screw head of the central screw connection.

Abstract: A mechanism for sealing gaps between a piston assembly and a cylinder for an internal combustion engine is provided. A sealing member inserted into an upper wall of a groove holding the oil ring to block a gap between them. The oil ring has two rails on its outer periphery. The upper rail is radially bigger than the lower rail and conforms better to the shape of the cylinder. The oil ring has a recess on its inner periphery to hold a pressing member that forces the oil ring against the cylinder. The recess is extended beyond the pressing member to provide a larger contact area between the oil ring and the groove.

Abstract: An internal combustion engine for enhancing a heat radiation property of combustion gas, can sufficiently secure strength thereof relative to combustion gas, and a weight reduction thereof can be realized. A piston for an internal combustion engine is constituted of a head part, a cylindrical skirt part extending from a lower part of the head part. A pair of pin boss parts are formed on both opposing side walls to each other of the skirt part. A plurality of recessed parts, the cross sections thereof being presented as smooth circular arcs, are formed on a surface on an opposing side to a surface facing to a combustion chamber of the head part, that is, to a reverse face.

Abstract: A steel monobloc piston for diesel engines is formed with a relatively short piston skirt whose lower edge resides below the axis of the pin bores of the piston, but located at or above a lowest tangent point of the pin bores. The piston body preferably has a closed oil cooling gallery and the skirt is preferably joined at its upper end to an outer wall of the piston in which a plurality of ring grooves are formed.

Abstract: A heavy duty diesel piston includes upper and lower portions joined across a friction weld and internally contoured to provide a dual gallery structure including an outer annular gallery and a central gallery joined by passages for communicating cooling oil therebetween. The dual-gallery structure allows oil to enter from the outer gallery, which is formed by the circumferential annular recess in the crown and crown bottom, into the central gallery to cool the piston and particularly the central crown region exposed to hot combustion gases. The friction weld provides high structural integrity and minimizes the number of manufacturing steps needed to attach the crown to the crown bottom.

Abstract: The aim of the invention is to provide an easy fastening of a tubular supply or a vertical pipe in a bottom covering of a cooling chamber for pistons of internal combustion engines, e.g. in a circular covering of a cooling channel of an articulated-skirt piston. To this end, the vertical tube or the tubular supply is clipped into the bottom covering or is fastened thereto by a detent connection.

Abstract: To lighten and miniaturize a piston and form a piston for a high-speed revolution. A top ring groove and an oil ring groove are formed on the periphery of a crown and a lubricator is provided inside the oil ring groove. A pair of piston pin bosses are provided continuously under the crown in opposite positions and a skirt is provided apart by 90°. The lower end of the skirt is located on the upside of the lower end of the piston pin boss and a lubricator is provided in an upper part of the skirt, under and in the vicinity of the oil ring groove.

Abstract: A piston ring includes a first radial flank; a second radial flank; and an outer rounded circumferential surface constituting a contact face of the piston ring. The rounded face has a circumferential crest line situated at a distance from the first radial flank which is more than one half of the axial piston ring height. The piston ring further has facing end surfaces defining a ring gap; and a circumferential groove provided in the outer rounded circumferential surface and extending axially from the second radial flank to the crest. The circumferential groove terminates adjacent each end surface at a distance therefrom.

Abstract: Methods are described, with which by expansion of metal foam it is possible in particular to manufacture pistons for brakes. This enables pistons of a very low wall thickness and high strength.

Abstract: A piston and compression ring combination with a piston having a generally cylindrical configuration for mounting in a cylinder of an internal combustion engine, an annular groove adjacent the top of the piston; and a piston ring having an upper inwardly directed flange adapted to rest on top of the piston, the ring having a lower inwardly retaining foot adapted for fitting into the ring groove in the piston. Such combination for the purpose of diminishing ring crevice volume, improving performance and reducing engine emissions.

Abstract: An object of the present invention is to effectively achieve the reduction in piston slap sound in both of an expansion stroke and a compression stroke in consideration of a difference between the behaviors of a piston in the expansion stroke and the compression stroke. For this purpose, in a piston P having a skirt 12 formed into an intermediately bulged barrel type, the axis L2 of a piston pin is offset with respect to the cylinder axis L1, and the decrement in radius of a lower skirt portion 20 is set to be large on a thrust side and small in an anti-thrust side. In the expansion stroke, the piston is positively swung, while the skirt 12 is put into abutment against a wall surface of a cylinder bore, thereby reducing the piston slap sound.

Abstract: An internal combustion engine for enhancing a heat radiation property of combustion gas, can sufficiently secure strength thereof relative to combustion gas, and a weight reduction thereof can be realized. A piston for an internal combustion engine is constituted of a head part, a cylindrical skirt part extending from a lower part of the head part. A pair of pin boss parts are formed on both opposing side walls to each other of the skirt part. A plurality of recessed parts, the cross sections thereof being presented as smooth circular arcs, are formed on a surface on an opposing side to a surface facing to a combustion chamber of the head part, that is, to a reverse face.

Abstract: An improved two-piece assembly having a piston skirt and piston crown made from two different materials. The piston assembly attaching to a piston rod without the use of an external bore in the piston skirt.

Abstract: The piston is provided with a hollow space in which a head member for a piston rod is mounted. A disc is provided within the piston for seating of the head member via mating concave/convex surfaces and a separate support ring is disposed under a flange of the head member with mating concave/convex surfaces therebetween. An annular clamping member serves to secure the disc ring and head member together and also abuts against an internal shoulder within the piston. Eccentric loadings on the piston are compensated by tilting movements between the head member and piston in a self-adjusting manner.

Abstract: It is frequently important for the piston of a hydraulic piston-and-cylinder assembly, in particular the brake piston of a disc brake, which is slidably arranged within a cylinder bore to ensure a true-to-size mounting position of the piston inside the cylinder bore. Especially in the case of brake pistons of a disc brake, this determines the efficiency of provisions on the brake piston for reducing the occurrence of brake noises. According to the present invention, a key-type accommodation is provided on the piston which permits engagement by a matingly configured mounting means or mounting tool and, thus, renders possible the defined positioning of the piston within a cylinder bore.

Abstract: A piston is formed with one or more recesses or depressions on its underside as it is cast, molded or forged. The recesses are located adjacent the outer cylindrical wall of the piston head so that when a groove such as an oil ring groove is subsequently machined into the outer wall, the groove intersects and cuts into each recess. In this manner, oil drain ports are formed in the oil ring groove without the need for additional boring or cutting operations.

Abstract: A piston (10) comprises a piston shaft (16) and an essentially cylindrical upper region (14). The piston shaft (16) essentially comprises two opposite shaft wall portions (16) relative to the pin axis. Two pin hubs (24) are also set back relative to the piston axis in the direction of the diameter of the piston shaft (16). On the piston are formed two communicating walls (18) which connect the shaft wall portions (16), which are also set back, which extend as far as the lower edge of the essentially cylindrical region (14) and in which the pin hubs (24) are located. According to the invention, the shaft wall portions (16) are provided in a largely concurrent manner with a dimension in the circumferential direction, this dimension varying in the direction of the piston axis. The communicating walls (18) also follow the thereby determined course of the edges of the two shaft wall portions (16), with these edges extending in the direction of the piston axis.

Abstract: A mushroom-type pin retainer for a pin having a central bore and which connects a piston and a piston rod of an internal combustion engine. The pin retainer is comprised of a mushroom head connected to a shaft. The shaft has a section of larger diameter for insertion into the bore of the pin. This section is no longer than 2 mm in an axial direction and is located remote from the mushroom head, so that the pin retainer may swing by a limited angle during mounting in the bore. This configuration makes the assembly simple to mount, even if it is manufactured by an imprecise manufacturing process such as injection molding.

Abstract: A piston pin for connecting a piston to a connecting rod especially but not exclusively of an internal combustion engine is made from a sleeve formed by a non-cutting rolling procedure at formation of a longitudinal slot. The longitudinal slot of the sleeve may extend in a plane defined by the longitudinal axis of the sleeve, or may have a wave-like configuration, or may be formed between longitudinal edges interlocking in the form of a tongue and groove. The outer surface of the piston pin is cylindrical while the interior thereof is formed with a central cylindrical section which terminates on both sides in sloped sections.

Abstract: A cast light metal piston of box-type construction for a two-stroke engine, comprising a piston blank having a gudgeon pin boss molded on a bottom section of the piston blank and a piston shaft having an open end and being connected to the gudgeon pin boss via approximately straight wall sections. There is only one lug disposed on only one side of the piston shaft. The wall section connecting the piston shaft with the gudgeon pin boss near the lug has a window-like recess. The wall section connecting the piston shaft with the gudgeon pin boss remote from the lug is closed and is raised upwardly with respect to the length of the shaft beginning from the open end of the shaft.

Abstract: A piston and connecting rod arrangement for internal combustion engines, including an upper piston part, a lower piston part and a connecting rod with a spherical connecting rod end. The spherical connecting rod end defines an upper spherical segment and a lower spherical segment, and a recess having a snoutlike cross section. The spherical connecting rod end is slidingly supported with the upper spherical segment in the spherical segmental indentation, and the recess is situated between the upper spherical segment and the lower spherical segment.