A piston, in particular, a gallery-cooled piston for an internal combustion engine has a piston bottom part and a piston upper part which are connected in a joining process to produce the piston. The piston upper part has at least one ring zone and an inner wall. The piston bottom part has a radially circumferential oblique surface at the end which faces the piston upper part. The oblique surface, interacting with the inner wall of the piston upper part, brings about a centering action during the joining process of the piston parts. A joining method for manufacturing a piston is also disclosed.

A hydraulic device includes a shaft mounted in a housing rotatable about a first axis of rotation. The shaft has a flange extending perpendicularly to the first axis. A plurality of pistons is fixed to the flange. A plurality of cylindrical sleeves cooperates with the pistons to form respective compression chambers of variable volume. The cylindrical sleeves are rotatable about a second axis of rotation which intersects the first axis of rotation by an acute angle such that upon rotating the shaft the volumes of the compression chambers change. Each piston has a piston head including a circumferential wall of which the outer side is ball-shaped and the inner side surrounds a cavity. Each of the pistons is fixed to the flange by a piston pin having a piston pin head including a circumferential outer side facing the inner side of the circumferential wall of the piston head.

The hydraulic piston with a depressurized groove is capable of translating in a cylinder and includes a fixed skirt, an axial compression face which forms with the cylinder a fluid chamber, and an axial working face which cooperates with a transmission; the piston also includes a seal, a depressurized radial groove emerging onto the surface of the fixed skirt, an axial decompression duct fitted inside the skirt which emerges in the vicinity of the axial working face, and a radial decompression duct which depressurizes the radial groove in communication with the axial decompression conduit.

A piston for an internal combustion engine includes a plurality of valve pockets formed in a piston rim, the valve pockets forming fluid flow paths through the piston rim. Each of the valve pockets includes a central step standing proud of a pocket floor to limit a fluid flow area through the pocket and slow combustion gas flow from a combustion bowl toward a cylinder liner and thereby reduce displacement of an engine oil film thereon.

A piston for a compressor includes a bearing portion having a cylindrical shape to define a suction space into which refrigerant is accommodated therein, the bearing portion being provided with a bearing surface facing an inner circumferential surface of the cylinder, a head portion coupled to a front opening of the bearing portion and provided with a plurality of suction ports which communicate with the suction space, the head portion having a compression surface configured to face a compression space to compress the refrigerant in the compression space, and a flange portion coupled to a rear opening of the bearing portion and provided with a through-passage through which the refrigerant is introduced from a muffler unit to the suction space, the flange portion being coupled to a driving portion to transmit driving force to the piston. The bearing surface is subjected to a surface treatment to improve abrasion resistance.

A piston rod includes a piston end that is removably attached to the piston rod body. A sleeve extends around the piston rod body and interfaces with a seal disposed within a pump. A ring extends from the piston end defines at least a portion of a socket formed in the piston end for connecting the piston end and the piston rod body. The ring has a cylindrical ring exterior and the sleeve rests on the cylindrical ring exterior such that the shank, the ring, and the sleeve radially overlap each other.

A system for controlling a wellbore pressure includes a body having a bore, a head coupled to the body, the head and body forming a chamber fluidly coupled to the bore, and a packer arranged in the chamber, the packer being moveable from a first position enabling flow through the floor and a second position blocking flow through the bore. The system also includes a piston positioned axially lower than the packer, the piston being moveable along an axis to drive the packer toward the second position from the first position, the piston having a removable sleeve including a sealing surface that engages at least a portion of a seal as the piston moves along the axis.

The invention relates to an actuator (1) for an automated or automatic transmission, having a cylinder housing (3), a piston unit (2), and a piston rod (13), wherein the piston unit (2) is coupled to the piston rod (13) and is arranged movably in the cylinder housing (3) along an axial longitudinal axis (4), wherein the piston unit (2) separates from each other two pressure chambers (8, 9) of variable volume in the cylinder housing (3), by means of which pressure chambers the piston unit (2) can be loaded with compressed air on both sides, wherein the two pressure chambers (8, 9) are connected to a valve unit (14) which is able to switch the pressurization or purging of each of the two pressure chambers (8, 9), and wherein an end stop damping device for damping at least one end stop of the piston unit (2) is arranged in the actuator (1). In order to improve the end stop damping device, a pneumatically and a mechanically operating damping stage are provided.

An internal combustion may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted within the cylinder. The piston may be configured to move in the cylinder in a first stroke from one end to another. The first stroke may include an expansion stroke portion and a non-expansion stroke portion. The non-expansion stroke portion may include a momentum stroke portion. The non-expansion stroke portion may include a scavenging phase. The engine may further include first and second piston rod portions extending from opposite faces of the piston. Passageways in the piston rod portions may be configured to communicate gases between a combustion chamber and other locations.

A piston for a compressor and a compressor including the same are disclosed. The piston is used in a compressor which compresses and discharges refrigerant suctioned into a cylinder. The piston includes a cylindrical slider and a head. The slider has an outer diameter corresponding to an inner diameter of the cylinder and defines a suction space in which the refrigerant suctioned in the cylinder is received. The head is coupled to the slider, in which a compression space is provided in the front and a suction space is provided in the rear, and in which a suction port communicating with the suction space and the compression space is formed, in which the head includes an inner body and an outer body surrounding the inner body, and the suction port is formed between the inner body and the outer body.