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 metal seal can be crushed evenly without forming wrinkles and scratches due to sliding against first and second flat surfaces. The seal comprises a first/second end surface arranged to face the first/second flat surface, respectively. The first end surface comprises a first convex part having a curved or flat surface that contacts the first flat surface, and a first projection that is formed shifted in a radial direction from the first convex part and has a ridge line that contacts the first flat surface. Prior to deformation, when the second end surface contacts the second flat surface and the first flat surface is separated from the first end surface, a point where a vertical distance between the first convex part and the second flat surface is the greatest and the ridge line are located on the same surface that is parallel to the first flat surface.

A metal seal can be crushed evenly without forming wrinkles and scratches due to sliding against first and second flat surfaces. The seal comprises a first/second end surface arranged to face the first/second flat surface, respectively. The first end surface comprises a first convex part having a curved or flat surface that contacts the first flat surface, and a first projection that is formed shifted in a radial direction from the first convex part and has a ridge line that contacts the first flat surface. Prior to deformation, when the second end surface contacts the second flat surface and the first flat surface is separated from the first end surface, a point where a vertical distance between the first convex part and the second flat surface is the greatest and the ridge line are located on the same surface that is parallel to the first flat surface.

A syringe system, piston seal systems, stopper systems, and methods for assembling and using the syringe systems. The piston seal system including a piston seal member and a piston head member. The injection system including a container, a piston seal system positioned within the container, and a stopper system coupled to an end of the container. The method of assembling an injection system, the method includes obtaining a container, a piston seal system, and a stopper system. The method also includes inserting the piston seal system into a cavity within the container. The method further includes securing the stopper system at an end of the container in an opening of the cavity. Methods of using the syringe system, piston seal systems, and stopper systems are also disclosed.

A hydraulic fluid cylinder is equipped with a cylinder tube, a piston unit, and a piston rod. The piston unit has a piston body comprising a plurality of members and provided with a gasket-mounting groove. The piston body has a first piston member and a second piston member which are layered in the axial direction. The gasket-mounting groove is formed from a combination of at least two members. A thin section exhibiting depth in the axial direction is provided in the first piston member and/or the second piston member.

A hydraulic device includes a cylinder, a piston that is able to move in the cylinder, and a segment which is interposed between the cylinder and the piston and which includes at least one leakage duct that is configured to generate a hydraulic film, between the segment and the piston, reducing friction and to orient a hydraulic flow leaving the leakage duct which causes the segment to rotate about the piston.

There is provided an engine piston including a piston main body and a piston pin. The piston main body includes a piston head that has a crown surface forming a part of a wall of a combustion chamber and a pair of pin bosses that are connected to a side of the piston head opposite to the crown surface, arranged with a distance between the pin bosses in a first direction included in a radial direction of the piston head, and respectively have pin holes for the piston pin, the pin holes penetrating in the first direction. The piston head includes a pair of hollow parts extending in a second direction orthogonal to both the axial direction and the first direction at a position between the crown surface and each of the pin holes in the axial direction and a particulate filler filled in the pair of hollow parts.

A high pressure fuel pump includes a pumping head and a plunger slidably adjusted in a bore. The plunger is provided with a blind bore defining a chamber open in the head end of the plunger and in fluid communication with the compression chamber, the end face of the plunger being limited to a peripheral annular face surrounding the opening, the bore further defining a peripheral cylindrical wall and a bottom face. A filler member is arranged inside the chamber.

A power cylinder system for a reciprocating engine includes a piston configured to move within a cylinder of the reciprocating engine. The system also includes a groove extending circumferentially about the piston and configured to support a ring. An axially-facing surface of the groove has circumferential undulations at ambient temperatures that are configured to compensate for distortions to the groove caused by operation of the reciprocating engine.