A piston and cylinder assembly of an axial piston machine is disclosed which includes a cylinder having a uniform internal diameter, a cylindrical bushing press-fit against the inner surface of the cylinder and extending at least partially therein, the bushing comprising at least one circumferential groove formed on an outer surface of the bushing against the inner surface of the cylinder, a piston reciprocably disposed within the cylindrical bushing, generating a piston-bushing-interface, the piston and the bushing defining a diametrical clearance therebetween, the diametrical clearance defining a lubrication gap and a fluid-dynamic seal between the piston and the cylindrical bushing.

The invention relates to an oil-free vacuum pump for evacuating gaseous media, comprising: an electric motor which drives a shaft; a pump housing having a pump chamber, as well as an inlet and an outlet; a prismatic displacement piston which is accommodated in the pump chamber such that it is bidirectionally active and can be moved on a reciprocal working section; and at least one pressure valve which releases an outflow of a gaseous medium out of the pump chamber through the outlet and blocks an inflow into the pump chamber. The displacement piston has a slot into which a drive force of the shaft is introduced via a crankpin by means of a rolling bearing.

An engine compressor unit including at least one rotary engine; and at least one rotary compressor for compressing at least one gaseous fluid; the rotary engine including an engine housing including at least one engine ring that is rotatably supported in the engine housing about an engine axis, at least one engine cylinder that is arranged in the engine ring, wherein an engine piston is arranged in the at least one engine cylinder so that the engine piston defines a combustion chamber of the at least one engine cylinder together with a wall of the at least one engine cylinder, wherein the engine piston is supported in the at least one engine cylinder by an engine connecting rod so that the engine piston is movable in the at least one engine cylinder in a linear manner.

A compressor (20) has a case (22) and a crankshaft (38). The case has a number of cylinders (30-32). For each of the cylinders, the compressor includes a piston (34) mounted for reciprocal movement at least partially within the cylinder. A connecting rod (36) couples each piston to the crankshaft. A pin (44) couples each connecting rod to the associated piston. Each pin has first (52) and second (53) end portions mounted to first (56) and second (57) receiving portions of the associated piston and a central portion (48) engaging the associated connecting rod. For each of the pistons a pair of first and second at least partially non-metallic plugs have respective stems received in the pin first and second end portions and respective heads facing a wall surface of the associated cylinder.

A compressor (20) has a case (22) and a crankshaft (38). The case has a number of cylinders (30-32). For each of the cylinders, the compressor includes a piston (34) mounted for reciprocal movement at least partially within the cylinder. A connecting rod (36) couples each piston to the crankshaft. A pin (44) couples each connecting rod to the associated piston.

Each pin has first (52) and second (53) end portions mounted to first (56) and second (57) receiving portions of the associated piston and a central portion (48) engaging the associated connecting rod. For each of the pistons a pair of first and second at least partially non-metallic plugs have respective stems received in the pin first and second end portions and respective heads facing a wall surface of the associated cylinder.

A reciprocating type compressor may include a crank shaft that is coupled to a rotor of a motor to receive a rotational force and a connecting rod that is coupled to a pin of the crank shaft and converts a rotational force of the crank shaft into a linear motion of a piston. The connecting rod may include a first end having a tubular body that includes a pin insertion hole into which the pin of the crank shaft is inserted and a socket that projects from the tubular body, a second end coupled with the piston, and a main body that extends between the first end and the second end and having a ball that is received inside of the socket.

A sensor system for determining a condition associated with a piston rod of a reciprocating system includes an interrogator system having a first antenna. The sensor system further includes a second antenna separated from the first antenna by an air gap distance. The second antenna is configured to be coupled to the piston rod of the reciprocating system. The second antenna is a patch antenna and is configured to communicate with the first antenna through a range of translational movement relative to the first antenna. The sensor system further includes a radio frequency sensor coupled to the second antenna. The radio frequency sensor is configured to be coupled to the piston rod of the reciprocating system, measure a characteristic associated with the piston rod of the reciprocating system, and transmit data associated with the characteristic to the first antenna of the interrogator system through the second antenna.

A piston cylinder arrangement for an air compressor including a cylinder, a connecting rod having a wrist pin receiving end, a wrist pin provided in the wrist pin receiving end of the connecting rod, and a piston provided on the connecting rod via the wrist pin and positioned within the cylinder. At least one passageway may be defined in the wrist pin to permit air to flow into the wrist pin from the cylinder.

A compressor (20) has a case (22) and a crankshaft (38). The case has a number of cylinders (30 32). For each of the cylinders, the compressor includes a piston (34) mounted for reciprocal movement at least partially within the cylinder. A connecting rod (36) couples each piston to the crankshaft. A pin (44) couples each connecting rod to the associated piston. Each pin has first (52) and second (53) end portions mounted to first (56) and second (57) receiving portions of the associated piston and a central portion (48) engaging the associated connecting rod. For each of the pistons a pair of first and second at least partially non metallic plugs have respective stems received in the pin first and second end portions and respective heads facing a wall surface of the associated cylinder.

A radial piston rotary machine includes a housing, at least one opening for inlet of a medium to the machine and at least one opening for outlet of the medium from the machine, where the housing includes end caps between which a rotor is rotatably mounted. The rotor is composed of at least two plates, where a chamber for a reciprocating piston is provided in the rotor plate. The rotor plates are separated by a partition plate with an opening for a shaft of the machine. The shaft is mounted in rotary bearings in the end caps of the housing and circular cams are arranged on the shaft. The shaft is mounted eccentrically to the rotor, where the eccentricity of the axis of rotation of the shaft from the axis of the rotor is equal to the eccentricity of the axis of the circular cam from the axis of rotation of the shaft. Each piston is placed movably in reciprocation motion in the chamber for the piston in the rotor plate and rotatably on the circular cam on the shaft. The inlet and outlet of the medium to and from the piston chamber are opened and closed by valve means. The chamber for the piston is formed as a hole in the rotor plate, where at least two opposite walls of the hole are parallel for sliding arrangement of the piston. The piston is closed axially in the chamber at one side by the partition plate of the rotor plates and at the other side by an end plate of the rotor. The end plate comprises-includes an opening for the shaft and apertures for the inlet and outlet of the medium to and from the chamber. The apertures lead in the axial direction to the end cap of the housing, and are opened and closed by valve means in the form of separate arcuate slots.