A compressor includes a compression mechanism that compresses refrigerant; a main shaft that transmits a rotational driving force to the compression mechanism; a balance weight provided below the compression mechanism and integrated with the main shaft, the balance weight having a cylindrical outer peripheral surface centered at the main shaft; and an oil sump portion provided below the balance weight and stores lubricating oil to be supplied to the compression mechanism. The balance weight has an annular oil-receiving recessed portion in an upper surface, the oil-receiving recessed portion being centered at the main shaft and integrated with the balance weight. The balance weight has a hollow portion in a lower surface, the hollow portion extending in part of the lower surface in a peripheral direction around the main shaft and being integrated with the balance weight. The oil-receiving recessed portion communicates with at least part of the hollow portion.

Inside a sealed container (101) of a refrigerant compressor (100), lubricating oil (103) having a kinematic viscosity at 40 C. of 0.1 mm.sup.2/S to 5.1 mm.sup.2/S is stored, and an electric element (106) and a compression element (107) are accommodated. The compression element (107) is provided with, as a shaft part, a crankshaft (108) comprising a main shaft (109) and an eccentric shaft (110), and as bearing parts, a main bearing (114) that axially supports the main shaft (109) and an eccentric bearing (119) that axially supports the eccentric shaft (110). At least one surface of the main shaft (109) and the eccentric shaft (110) is subjected to a surface treatment, e.g., formation of an oxide film, having a hardness equal to or greater than that of a bearing part (the main bearing (114) or the eccentric bearing (119)). Satisfactory reliability in sliding parts can thereby be achieved even if lubricating oil having lower viscosity is used.

A compressor may include a hermetic case to store oil in a lower portion thereof, a compression mechanism part to compress a refrigerant, a power train part to generate a driving force, a rotational shaft to transmit the driving force generated from the power train part to the compression mechanism part and including a hollow portion and a female screw part formed at the hollow portion, and an oil pumping member inserted into the hollow portion of the rotational shaft and including an oil pumping part which moves the oil stored in the lower portion of the hermetic case up and a male screw part which is coupled to the female screw part of the rotational shaft. Since the oil pumping member and the rotational shaft are firmly coupled to each other, the reliability of the oil supplying is improved.

Disclosed is a trochoid lubricant supply device that is configured to connect to a rotational shaft. A connector of the lubricant supply device is configured to reduce an oil leakage amount of lubricant, and is configured to insert to a lower portion of a rotational shaft. The connector includes: a rotator mounting member inserted into and fixed to the rotator of the lubricant supply device; a penetrating member that penetrates a fixer of the lubricant supply device; an enlarged diameter extending radially outwards from the penetrating member outside the fixer; and a rotational shaft mounting member extending axially in the diameter enlarged member and is fastened to the rotational shaft. Further, the lubricant supply device of the present disclosure can supply the oil regardless of a rotation direction of the rotational shaft by supplying the oil by a space pivoting about the rotational center of the rotator.

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 hermetic compressor includes an electric motor element driving a compression element that includes a crankshaft including a main shaft, an eccentric shaft, and a flange, a cylinder block having a cylinder bore, and a piston configured to reciprocate in the cylinder bore. The crankshaft further includes a communicating oil supply passage provided in the flange, a main shaft oil supply passage, and an eccentric shaft oil supply passage.

Disclosed herein is a compressor having an improved oil supply structure. The compressor includes: a case; a stator, accommodated in the case, and including a stator core; a rotor rotatably disposed in an inside of the stator core; a bracket coupled to a lower portion of the stator core; a rotation shaft configured to rotate together with the rotor, and having a cavity for raising oil stored in the case; a pickup shaft accommodated in the cavity; and a support member connected to the pickup shaft to support the pickup shaft, and coupled to the bracket.

The arrangement of the present invention is applied to a compressor which comprises a bearing hub housing a crankshaft and presenting at least a first and a second bearing portion, spaced apart by a circumferential recess. The crankshaft presents at least a first and a second support portion, spaced apart by a circumferential recess, which is offset from the circumferential recess of the bearing hub. At least one of the bearing portions and support portions has an axial extension superior to that required for radially bearing the crankshaft, the first and second bearing portions defining, with the first and second support portions, respectively, a first and a second radial bearing regions having the axial extensions required for a radial bearing for the crankshaft, presenting lower loss by viscous friction.

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.

A compressor includes a closed container housing a compression element driven by the shaft of a motor. The compression element includes a first and second bearings supporting first and second shaft portions, and at least one cylinder having at least one cylinder chamber disposed between the first and second bearings. At least one roller is fitted to the shaft in the at least one cylinder chamber. The first bearing is disposed closer to the motor than the second bearing. The first and second bearings have first and second annular grooves opened to the at least one cylinder chamber and first and second elastic portions provided in first and second opposing surfaces, respectively. A diameter of the second shaft portion is smaller than a diameter of the first shaft portion. A rigidity of the second elastic portion is smaller than a rigidity of the first elastic portion.