Abstract: A compressor is operable to compress refrigerant at a variable operation frequency. According to a method of controlling the compressor, the compressor starts operating, and just after that, the compressor operates at a first frequency for a first period of time. Just after that, the compressor operates at a second frequency lower than the first frequency for a second period of time longer than the first period, and after that, the compressor operates at an ordinary operation. This method does not cause the compressor to generate an abnormal noise or obstruction to lubrication.

Abstract: A hermetic compressor including a housing containing oil and a compression mechanism for compressing a refrigerant gas. In this configuration, a cylindrical piston has under cuts which do not communicate with at least a top surface at a cylinder side of the piston and are formed on an outer circumferential surface of the piston excluding a sliding surface existing in the axial direction of a piston pin and the perpendicular direction of the piston pin viewed from the axial direction of the piston, in which the under cuts communicate with space inside the housing in the vicinity of the bottom dead center. Since the sliding surface is provided in the direction parallel to and perpendicular to the axis, inclination of the piston in the vertical direction is suppressed and at the same time oil supply to the sliding portion through the under cuts is promoted. Therefore, the sealing property and lubricant property are improved, and thus high efficiency of the compressor can be realized.

Abstract: A compressor is operable to compress refrigerant at a variable operation frequency. According to a method of controlling the compressor, the compressor starts operating, and just after that, the compressor operates at a first frequency for a first period of time. Just after that, the compressor operates at a second frequency lower than the first frequency for a second period of time longer than the first period, and after that, the compressor operates at an ordinary operation. This method does not cause the compressor to generate an abnormal noise or obstruction to lubrication.

Abstract: A closed motor-driven compressor includes a closed vessel containing a lubricating oil collected in a bottom portion thereof, a compression section accommodated in the closed vessel, and a motor section accommodated in the closed vessel for driving the compression section. The compression section includes a crankshaft driven by the motor section and having a lower end submerged in the lubricating oil, and a block for rotatably supporting the crankshaft. The block has a cylinder formed therewith and having an open end. The block also has a rib formed therewith, a generally flat shoulder portion formed on one side of the cylinder, and a leg formed below the generally flat shoulder portion. The compression section also includes a cylinder head secured to the rib for covering the open end of the cylinder.

Abstract: A hermetic compressor includes a sealed casing which accommodates therein a compressing unit for compressing a refrigerant and a driving unit for driving the compressing unit. A communication passage is provided for establishing communication between the compressing unit and a discharge muffler. The discharge muffler is formed therein with a substantially annular hermetic passage for the compressed refrigerant introduced via the communication passage. In the substantially annular hermetic passage, the introduced compressed refrigerant is bifurcated in opposite directions. The substantially annular hermetic passage has an outlet in the discharge muffler. At the outlet, the bifurcated refrigerant joins and flows out of the substantially annular hermetic passage so as to reduce pressure pulsation of the compressed refrigerant by canceling pressure pulsation components contained in the bifurcated refrigerant.

Abstract: A compressor equipped with a compressing unit comprising a compressing section and a motor section which are connected to each other and Which are encased in a closed vessel, the compressing section including a crank shaft rotatable so that a piston reciprocates within a cylinder and the motor section comprising a rotor and stator and disposed at a lower side of the compressing section, the rotor being connected to the crank shaft so that the crank shaft is rotatable in response to driving of the motor section. Springs are provided between the compressing unit and the closed vessel so as to elastically support the compressing section and the motor section, and first and second balance weights are respectively provided on upper and lower portions of a rotor of the motor section.

Abstract: A hermetic compressor includes a sealed casing which accommodates therein a compressing unit for compressing a refrigerant and a driving unit for driving the compressing unit. An induction pipe is provided in the sealed casing for introducing the refrigerant into the compressing unit. The induction pipe has an outlet end communicating with the interior of the compressing unit and an inlet end which is opened to space in the sealed casing at a position corresponding to a node of a standing wave of the refrigerant in the sealed casing.