A piston assembly is provided for a human-powered vehicle. The piston assembly includes a main body and a primary seal. The main body is configured to be movable from a rest position to an actuated position along an actuation direction in a cylinder bore. The primary seal includes a primary seal body arranged on the main body. The primary seal body is made of a resin material. The main body includes a first part and a second part. The first part is at least partly arranged upstream of the primary seal with respect to the actuation direction. The second part is coupled to the first part to be at least partly arranged downstream of the primary seal with respect to the actuation direction. The at least one of the first part and the second part includes a support portion supporting the primary seal.

A clutch assembly for a transmission of an agricultural work vehicle. The clutch assembly includes a housing, a clutch pack located within the housing, a piston chamber located within the housing, and a multipart piston located within and slidable relative to the piston chamber. The multipart piston is operably connected to the clutch pack for engaging and disengaging the clutch pack. The multipart piston includes a lower piston extension part. The clutch assembly further includes a balance chamber that is located within the housing. The lower boundary wall of the balance chamber and the lower boundary wall of the piston chamber are radially separated from one another by a substantial distance. The lower piston extension part is located within the balance chamber for adding to a collective surface area of the balance chamber.

A piston (1) comprising a first portion (10) suitable for coupling with an actuator member (53) and a second portion (20) made of ceramic material suitable for sliding in a cylinder (51). The first portion (10) and the second portion (20) are axially connected along a longitudinal axis (L) of the piston (1). The second portion (20) has an elongated shape along the longitudinal axis (L) of the piston (1), with an interface base (21) proximal to the first portion (10) and a free base (23) distal from the first portion (10). Moreover, the free base (23) is closed and entirely defines a piston crown.

A piston (1) comprising a first portion (10) suitable for coupling with an actuator member (53) and a second portion (20) made of ceramic material suitable for sliding in a cylinder (51). The first portion (10) and the second portion (20) are axially connected along a longitudinal axis (L) of the piston (1). The second portion (20) has an elongated shape along the longitudinal axis (L) of the piston (1), with an interface base (21) proximal to the first portion (10) and a free base (23) distal from the first portion (10). Moreover, the free base (23) is closed and entirely defines a piston crown.

A structure of a combustion chamber for an engine includes a crown surface of a piston, a combustion chamber ceiling surface formed on a cylinder head, an injector and an ignition plug provided on the combustion chamber ceiling surface, and an intake opening and an exhaust opening opened in the combustion chamber ceiling surface. A side where the intake opening is opened is defined as an intake port side, and a side where the exhaust opening is opened is defined as an exhaust port side, with respect to a position, as a reference, where an ignition portion of the ignition plug is disposed in a plan view from one side in a cylinder axis direction, the injector is configured to inject fuel toward the exhaust port side, and a reverse squish flow generation portion, which draws an air-fuel mixture toward the intake port side, is provided in the combustion chamber.

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.

A piston includes: a piston head; and a piston skirt connected to the piston head, wherein the piston skirt includes wall portions protruding outward from a surface of the piston skirt, the wall portions adjacent to each other in a circumferential direction of the piston skirt are inclined in directions opposite to each other with respect to a direction of movement of the piston in a bore for the piston, and define a tapered portion, and the tapered portions are spaced away from each other in the circumferential direction of the piston skirt.

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 top surface of the piston includes a first region. A heat shielding film is formed on the first area. The top surface further includes a second region. There is no heat shielding film formed on the second region. Instead, the second area is mirror-finished. The top surface includes a central portion. A valve recess portion is formed on an intake side of the central portion. A squish portion is formed the intake side of the valve recess portion. The first area includes at least the central portion. The second area includes at least the squish portion.