Provided is a variable displacement compressor that is directed to cost reduction and productivity enhancement of a second control valve that adjusts an opening degree of a discharge passage for discharging a refrigerant in a controlled pressure chamber to a suction chamber. The variable displacement compressor includes the second control valve (400) configured to decrease an opening degree of the discharge passage to a minimum value when a first end surface (421a) of a valve body (420) accommodated in a valve chamber (410) comes into contact with a first end wall surface (411) of the valve chamber (410) to close a second port (432) and a third port (433), and configured to increase the opening degree of the discharge passage to a maximum value when the first end surface (421a) of the valve body (420) separates from the first end wall surface (411) of the valve chamber (410) to open the second port (432) and the third port (433). The valve body (420) is supported movably in a direction perpendicular to the first end wall surface (411) without contact with a peripheral wall surface (413) of the valve chamber (410), by a guide shaft portion (415a) being slidably inserted into a receiving portion (423) formed at a radially center portion of the valve body (420).

An axial piston pump having several pistons has a magnetic encoder (5), which is arranged on a swash plate, and a magnetic field sensor, which is arranged in such a way that it faces towards the magnetic encoder (5). The magnetic encoder (5) has at least two permanent magnets (2, 3) and a plate (4) which consists of a ferromagnetic material. The permanent magnets (2, 3) are arranged on the plate (4) in such a way that they each faces a magnetic pole towards the plate (4), and this pole is at least partially covered by the plate (4) in each case.

In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter. The control device performs a control whereby compressed gas having a prescribed pressure is generated/maintained by increasing/decreasing the frequency, and when the frequency that generates the compressed gas having the prescribed pressure includes a specific frequency, the inverter's output frequency is increased or decreased when the pressure detected by the pressure detection means reaches a pressure corresponding to a frequency that has a more constant pressure width than the prescribed pressure and does not include the specific frequency.

In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter. The control device performs a control whereby compressed gas having a prescribed pressure is generated/maintained by increasing/decreasing the frequency, and when the frequency that generates the compressed gas having the prescribed pressure includes a specific frequency, the inverter's output frequency is increased or decreased when the pressure detected by the pressure detection means reaches a pressure corresponding to a frequency that has a more constant pressure width than the prescribed pressure and does not include the specific frequency.

There is provided a shoe capable of suppressing deformation of a member on which the shoe slides. The shoe includes: a first sliding surface which slides on a concave surface of a piston (first movable member); and a second sliding surface which bulges toward a side opposite to the first sliding surface and slides on a flat surface of a swash plate (second movable member). The second sliding surface includes: a curved outer peripheral portion which is provided along an outer periphery of the second sliding surface; and a central portion which is provided at a center of the second sliding surface so as to be continuous with the curved outer peripheral portion and has a radius of curvature greater than a radius of curvature of the curved outer peripheral portion.

A cam driven compressor includes a cam coupled to a plurality of cylinder and piston assemblies. Each cylinder and piston assembly comprises a piston located and movable within a respective cylinder. Each cylinder has a cylinder head. The compressor comprises a housing defining a cavity configured to receive a portion of a source gas from one or more of the cylinders in order to maintain a positive gas pressure within the cavity.

A compressor includes a shaft, a motor unit that causes the shaft to rotate, a compressor unit that compresses a refrigerant according to rotation of the shaft, and a housing that stores therein the shaft, the motor unit, and the compressor unit, wherein the housing and the motor unit are joined by welding in a plurality of welding areas, the motor unit includes a rotor that is fixed to the shaft, and a stator core that surrounds the rotor, a plurality of core sheets are superimposed in the stator core and the stator core includes a plurality of teeth around which a coil is wounded and a plurality of swaging fixing areas where swaging areas fix the core sheets mutually, and the welding areas are formed in only positions corresponding to the swaging fixing areas.

Disclosed is a suction damping case. A refrigerant introduced into the suction damping case flows for a predetermined period of time at reduced pressure and speed, and then is discharged to the outside of the body, so that a damping function can be made. When the suction damping case is coupled to a rear housing, a hook and an embossing prevents the suction damping case from being separated.

A piston pump includes a rotor member with a bore therein. The bore is defined by an inner surface. The piston pump also includes a piston supported for reciprocating movement in an axial direction within the bore to change a volume of a pump chamber that is cooperatively defined by the piston and the rotor member. The piston has an outer surface that faces the inner surface with a leakage interface defined therebetween. The leakage interface is configured to receive a passive leakage flow of a fluid from the pump chamber through the leakage interface to provide cooling. Moreover, the outer surface includes a relief feature that is recessed into the outer surface to define, with the inner surface, a cooling pocket of the leakage interface. The cooling pocket moves in the axial direction relative to the inner surface with the reciprocating movement of the piston.

A linear compressor and a method for manufacturing a linear compressor are provided. A piston of a linear compressor may include a surface treatment body made of aluminum or an aluminum alloy; a first surface treatment provided on an outer surface of the surface treatment body by a first vacuum deposition process; and a second surface treatment provided on an outer surface of the first surface treatment by a second vacuum deposition process.