Abstract: A compressor has stator of a motor is installed in a closed container, on two planes normal to the center axis 1a of the container. On each of the planes, the stator is welded to the container at three welding points. This mounting arrangement on two planes with three welding points on each plane minimizes the amount of movement of the stator in the direction of the center axis.

Abstract: A stator core of a motor has a plurality of oil return passages extending through one surface and the other surface of the core. On the other surface of the stator core, a hydraulic diameter of each oil return passage is 5 mm or larger, and a ratio of a total area of the oil return passages to an area of a virtual circle having a diameter equal to a maximum outer diameter of the stator core is 5 to 15%. Lubricating oil accumulated on the other surface side of the stator core is returned to an oil reservoir through the oil return passages, and shortage of oil in the oil reservoir is prevented. Furthermore, a cross sectional area of the stator core can be securely kept, and motor efficiency is maintained.

Abstract: In a scroll compressor, a sliding direction of a Oldham coupling is defined such that an acting direction of an inertia force of the Oldham coupling is substantially opposite to an acting direction of a reaction force by gas compression, and thereby a range of fluctuation of a total torque of a first rotational torque acting on an orbiting scroll by the reaction force of gas compression and a second rotational torque of sliding movement of the Oldham coupling becomes smaller than that of the first rotational torque to suppress a noise and vibration caused by fluctuation of a rotational torque of the orbiting scroll without any limited designing of an involute shape thereof.

Abstract: In a scroll compressor, a sliding direction of a Oldham coupling is defined such that an acting direction of an inertia force of the Oldham coupling is substantially opposite to an acting direction of a reaction force by gas compression, and thereby a range of fluctuation of a total torque of a first rotational torque acting on an orbiting scroll by the reaction force of gas compression and a second rotational torque of sliding movement of the Oldham coupling becomes smaller than that of the first rotational torque to suppress a noise and vibration caused by fluctuation of a rotational torque of the orbiting scroll without any limited designing of an involute shape thereof.

Abstract: A front head (23) of a cylinder (21) and a mounting plate (40) are tightly fixed to each other. The mounting plate (40) is welded to a casing (10). The mounting plate (40) is made of steel containing 2.0% or less of carbon therein. Furthermore, a stator core (34) of a compressor motor (30) is welded to the casing (10). A hermetic sealed compressor is configured in a high-pressure domed type. A supercritical fluid is used as an operating fluid.

Abstract: In a scroll type compressor (1) that includes a fixed scroll (21) fixed inside of a casing (10) and a movable scroll (22) meshed with the fixed scroll (21) and presses the movable scroll (22) against the fixed scroll (21), the pressing force of the movable scroll (22) against the fixed scroll (21) is obtained from the pressure of a high-pressure space (S2) that acts on the back face of the movable scroll (22) and the pressing force is controlled in accordance with the variation in the compression ratio with the change in the operating condition thereby preventing decrease in efficiency and mechanical loss.