In order to avoid over-lubrication of the cylinders (2) in a piston compressor (1) and to reduce the amount of lubricant to a level required for operation, according to the invention, a lubricating system having a lubricating system control unit (14) is provided, in which system at least one lubricant sensor (15) is provided for detecting a lubricating film measurement variable (S) representative of a lubricating film thickness of a lubricating film (11) on the cylinder surface of the cylinder (2), the lubricating system control unit (14) being designed to operate the lubricating system at least once in a predetermined calibration operating mode during operation of the piston compressor (1) and to determine a lubricating film state value (SZ) on the basis of the lubricating film measurement variable (S) detected during execution of the calibrating operating mode and the lubricating system control unit (14) being designed, after the end of the calibration operating mode during operation of the piston compressor (1), to control the amount of lubricant to be introduced depending on the determined lubricating film state value (SZ).

A lubricating oil supply apparatus having a structure in which a valve is forced in a direction for opening a bypass hole by a centrifugal force, and a spring presses the valve in a direction in which the valve closes the bypass hole. When the above-described structure is applied to an oil pump in which an oil (lubricating oil) supply amount increases in proportion to an operation speed, it is possible to secure a sufficient oil (lubricating oil) supply amount in a low speed operation mode, and prevent oil from being supplied more than necessary in a high speed operation mode.

Some embodiments of the present disclosure provide a compressor and an air conditioner with the compressor. The compressor includes: a first compression part, a second compression part, an intermediate cavity and an intermediate passage. Refrigerant discharged from the first compression part enters the intermediate cavity. The intermediate passage communicates with the intermediate cavity and an inner cavity of the second compression part. A bottom port of the intermediate passage is located at a bottom of the intermediate cavity, and air supplement refrigerant and/or the refrigerant discharged from the first compression part are used to convey accumulated oil in the intermediate cavity to the inner cavity of the second compression part. When only the refrigerant is used to convey the accumulated to the inner cavity of the second compression part, at least a part of the intermediate passage is located outside of a housing assembly of the compressor.

A linear compressor includes a cylinder that defines a compression space of a refrigerant and has a cylindrical shape, and a piston disposed in the cylinder and reciprocating along an axis of the cylinder. The cylinder includes a supply port radially passing through the cylinder, and a recess formed on an inner circumferential surface of the cylinder and communicating with the supply port. The supply port includes a first supply port and a second supply port disposed in a rear of the first supply port, and the recess includes a first recess and a second recess disposed in a rear of the first recess. The first recess and the second recess are formed in different shapes.

A lubricating oil supply apparatus may include a rotational portion that rotates together with a rotational shaft and a fixed portion that maintains a fixed location thereof and supplies oil through a space that circles with respect to a rotational center of the rotational portion, thereby supplying oil regardless of a rotational direction of the rotational shaft.

A compressor and a refrigeration system having the same are provided. The compressor includes a crankcase, a thrust bearing and a crankshaft. The crankcase is formed with a crankshaft hole therein and provided with a mounting protrusion at an upper end thereof. The crankshaft hole runs upward through the mounting protrusion. The thrust bearing is fitted over the mounting protrusion. The crankshaft is rotatably disposed within the crankshaft hole, has a thrust part, and is formed with an oil supply passage therein. A lower end face of the thrust part is abutted against an upper end face of the thrust bearing. A cavity is defined by the mounting protrusion, the thrust bearing and the thrust part. A through hole is formed in a peripheral wall of the crankshaft for communicating the oil supply passage with the cavity.

In order to prevent working medium from accumulating in the compressor housing (2) of a piston compressor (1) in a simple manner by means of a sealing of the piston rod (7) in the form of sealing medium barrier supplied by a hydraulic unit (12), it is provided that a ventilator (32) and a sealing medium container (37), which is partially filled with sealing medium, are provided in the hydraulic unit (12), wherein the ventilator (32) suctions air from the free space of the sealing medium container (37), and the free space (45) in the sealing medium container (37) is connected via a line (15, 17) to the compressor housing (2), and an opening (16) is provided at the compressor housing (2) for connecting the interior of the compressor housing (2) to a purge gas reservoir (18).

A linear compressor is provided that may include a shell provided with a refrigerant inlet; a cylinder provided inside of the shell to form a compression space; a piston that reciprocates inside of the cylinder to compress a refrigerant in the compression space; and a motor assembly that provides a drive force to the piston and provided with a permanent magnet. The piston may include a piston body having a cylindrical outer circumferential surface and a surface-treated area, which may be processed with a material having a predetermined hardness value, and a valve support provided at an end of the piston body and having a suctioning hole be in communication with the compression space. The valve support may form a first non-surface-treated area, which is not surface-treated.

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.

A linear compressor includes a mover which linearly reciprocates, a stator generating a driving force to allow the mover to linearly reciprocate and having a cylinder space formed on an inner circumferential surface thereof, a cylinder inserted into the cylinder space of the stator and having a compression space compressing a refrigerant, a piston reciprocating in an axial direction inside the cylinder, a frame provided on one side of the stator in an axial direction and supporting the stator in the axial direction, and a cylinder support member separated from the frame, provided between an inner circumferential surface of the stator and an outer circumferential surface of the cylinder, having one end fixed to the stator and the other end fixed to the cylinder, and supporting the cylinder with respect to the stator in the axial direction.