A reciprocating compressor includes a cylinder that defines an inner space, a piston that is located in the inner space of the cylinder and that defines a compression space configured to receive refrigerant, a discharge cover that is coupled to a side of the cylinder and that defines a discharge space configured to receive refrigerant discharged from the compression space, and a valve plate that is located at a side space defined at the side of the cylinder and that partitions the side space into the compression space and the discharge space. The valve plate defines a discharge hole through which the compression space and the discharge space communicate with each other, in which the discharge hole includes an inlet that faces the compression space and an outlet that faces the discharge space. The inlet and the outlet have different shapes.

A sealed refrigerant compressor (100) includes: a compression element (107) accommodated in a sealed container (101) and configured to compress a refrigerant; and an electric element (106) configured to drive the compression element (107). Lubricating oil (103) is stored in the sealed container (101). A resin member is included as a member accommodated in the sealed container (101). The amount of oligomer contained in the resin member is 2.5 wt. % or less of an entire weight of the resin member. Kinetic viscosity of the lubricating oil 103 at 40 C. falls within a range of 0.1 to 5.1 mm.sup.2/s. A flash point of the lubricating oil 103 is 110 C. or more.

An oil distributing device and a refrigeration system having the oil distributing device are disclosed. The oil distributing device is connected among at least three compressors and is configured to distribute oil among the at least three compressors. The oil distributing device includes: a first joint assembly including a plurality of passages fluidly isolated from each other; a plurality of second joint assemblies; and a plurality of connecting pipes respectively connecting the plurality of second joint assemblies to the plurality of passages of the first joint assembly in one-to-one correspondence. For example, the oil distributing device and the refrigeration system according to the embodiments of the present invention can achieve a better oil balance control.

A compressor includes a compression mechanism to compress gas and discharge compressed gas, an electric motor to drive the compression mechanism, a casing housing the compression mechanism and the electric motor, a suction pipe connected to a suction side of the compression mechanism via the casing, and a discharge pipe provided at the casing to open in a space in the casing. The space has a first space located below the motor, and a second space located above the motor. The compression mechanism is disposed in the first space. The compressor is provided with a partition plate disposed in the second space, and the having a gas passage hole. The partition plate further has an oil drain hole formed at a lower level than an open end of the gas passage hole, and located radially outside an outer peripheral surface of a rotor of the electric motor.

There is provided a technology for properly preventing an insulation member from melting during welding without reducing the efficiency of a motor. A compressor includes: a motor including a shaft, a rotor fixed to the shaft, and a stator surrounding the rotor; a compression unit that compresses a refrigerant as a result of rotation of the shaft; and a shell that houses the shaft, the motor, and the compression unit therein. The stator includes a stator core including an annular back yoke portion, a plurality of teeth portions, and slots formed between adjacent teeth portions, coils wound around the plurality of teeth portions, an insulation member that is disposed in the slots and interposed between the stator core and the coils to insulate the stator core and the coils, and at least one projection portion that forms a gap.

Provided is an air compressor which helps to attain a proper discharge air temperature and which is superior in energy saving property. There are provided an air line connecting an air compressor, an oil separator, and an after cooler; an oil circulation line connecting the air compressor, the oil separator, and an oil cooler; a bearing oil supply line connecting one end of an intermediate branching portion disposed at an intermediate point of the oil circulation line between the oil cooler and the air compressor to a bearing oil supply portion of the air compressor; an intermediate portion oil supply line connecting the other end of the intermediate branching portion to an intermediate oil supply portion of the air compressor; a branching line supplying oil to the bearing oil supply portion and the intermediate oil supply portion; a blower sending air to the oil cooler and the after cooler; a bypass line connecting one end of a bypass branching portion disposed at an intermediate point of the oil circulation line between the oil separator and the oil cooler to the downstream side of the oil cooler of the bearing oil supply line; and a control valve controlling the inflow amount of the lubricating oil to the bypass line.

A hermetic compressor (100) includes an electric element (110), a compression element (112), and a hermetic container (102). The compression element includes a shaft (118), a cylinder block (124), a piston (136), a connection section (144), and an oil supply mechanism (130). The piston has a columnar seal section (160) in sliding contact with an inner peripheral face of the cylinder, two extension sections (162) that have circular arc faces each having the same radius as a radius of the seal section and extend from the seal section to the bottom dead center side in the axial direction with a circumferential gap therebetween, and a columnar capture section (164) that extends further toward the bottom dead center side than the extension section and has a smaller radius than the radius of the seal section.

A compressor includes a casing having a cylindrical barrel, a compression mechanism, and an electric motor. The electric motor has a tubular stator, and a rotor disposed inside the stator. The stator has a back yoke forming an outer peripheral portion of the stator, a plurality of teeth extending radially inward, and slots. A fluid passage extends between an outer peripheral surface of the stator and an inner peripheral surface of the barrel. The fluid passage has a plurality of wide portions arranged in a circumferential direction of the stator, and a narrow portion provided between adjacent ones of the wide portions. The narrow portion has a smaller radial width than each of the wide portions. Each wide portion is provided in the outer peripheral surface of the stator and between a core cut having a recessed groove shape between the slots and the inner peripheral surface of the barrel.

A reciprocating compressor according to the present invention includes a stator disposed in an inner space of a shell, and having a stator core with at least one air gap, and a coil fixed to the stator core, a piston mechanically connected with a magnet, and reciprocating by magnetic energy generated in the stator and interaction with the magnet, a cylinder having the piston inserted therein and forming a compression space, a suction valve opening/closing a suction side of the compression space, a discharge valve opening/closing a discharge side of the compression space, and an electromagnetic resonance spring formed between the stator and the magnet by a restoring force generated by the magnetic energy.

A reciprocating compressor includes a cylinder that defines an inner space, a piston that is located in the inner space of the cylinder and that defines a compression space configured to receive refrigerant, a discharge cover that is coupled to a side of the cylinder and that defines a discharge space configured to receive refrigerant discharged from the compression space, and a valve plate that is located at a side space defined at the side of the cylinder and that partitions the side space into the compression space and the discharge space. The valve plate defines a discharge hole through which the compression space and the discharge space communicate with each other, in which the discharge hole includes an inlet that faces the compression space and an outlet that faces the discharge space. The inlet and the outlet have different shapes.