Abstract: To reduce an excessively high vane back pressure to an appropriate pressure to thereby relieve operational load, and to improve the vane projectability at the start and during low speed operation to thereby prevent chattering; There are provided back pressure spaces including the bottom portion of vane grooves and attaining a middle pressure between suction pressure and discharge pressure during normal operation of the compressor main body, a first high pressure oil passage establishing communication between an oil sump and the vane groove bottom portions when the vanes are in their discharge stroke positions, second high pressure oil passages establishing communication between the oil sump and the back pressure spaces, and an opening/closing valve for opening and closing the second high pressure oil passages.

Abstract: A gas compressor has a cylinder in which a refrigerant gas is compressed and a side block mounted to an end surface of the cylinder. The side block has suction holes each having a first end opening to an outer surface of the side block and a second end opening into the cylinder. A front head has a suction port, an inner surface, and a hollow portion disposed in the inner surface. The front head is disposed on an outer surface of the side block so that the hollow portion and the outer surface of the side block form suction passages extending from the suction port to respective suction holes of the side block. Each of the suction passages form a main flow passage along which refrigerant gas flows from the suction port to a corresponding one of the suction holes of the side block. The hollow portion has a generally flat wall surface at a region corresponding to each of the main flow passages.

Abstract: A rotary vane gas compressor has a cylinder, a rotor in the cylinder, and vanes slidably disposed in radial vane grooves in the rotor to define compression chambers for intaking, compressing and discharging compressed gas during rotation of the rotor. A flat groove communicates with bottom portions of the vane grooves during intaking and compression of the gas in the compression chambers, and a high pressure supplying hole communicates with the bottom portions of the vane grooves during end stage compression of the gas at times when the bottom portions of the vane grooves are not in communication with the flat groove. A communication passage establishes communication between the flat groove and the high pressure supplying hole at the start of operation of the gas compressor to supply high pressure gas to the vane groove bottom portions during start-up to quickly urge the vanes into contact with the cylinder.

Abstract: To reduce an excessively high vane back pressure to an appropriate pressure to thereby relieve operational load, and to improve the vane projectability at the start and during low speed operation to thereby prevent chattering; There are provided back pressure spaces including the bottom portion of vane grooves and attaining a middle pressure between suction pressure and discharge pressure during normal operation of the compressor main body, a first high pressure oil passage establishing communication between an oil sump and the vane groove bottom portions when the vanes are in their discharge stroke positions, second high pressure oil passages establishing communication between the oil sump and the back pressure spaces, and an opening/closing valve for opening and closing the second high pressure oil passages.

Abstract: To provide a gas compressor improved in terms of the vane projectability at the start of the compressor. To achieve the above object, there is provided a communication passage establishing communication between a high pressure supplying hole and a flat groove at the start of the compressor, and high pressure refrigerant gas discharged into the high pressure supplying hole at the start of the compressor is supplied to the flat groove, whereby high pressure refrigerant gas is supplied to vane groove bottom portions, making it possible to improve the projectability of vanes.

Abstract: To provide a gas compressor which is small-sized and suitable for achieving an improvement in terms of cooling capacity. There is formed in the inner surface of a front head a passage-like hollow portion branching off from a suction port of the front head and extending toward two side block suction holes, and a suction passage is formed for each side block suction hole by the passage-like hollow portion in the inner surface of the front head and an outer surface of a side block. A Low-pressure refrigerant gas compressed in a cylinder is conveyed from the suction port of the front head through the bifurcated suction passages to be sucked into the cylinder through the side block suction holes.

Abstract: A composite-type electromagnet for a radial magnetic bearing has four composite-type electromagnet parts. Each part has four electromagnet cores formed of a magnetic material. The cores each have two protruding poles. A control coil is wound around each of the protruding poles and a biasing permanent magnet is disposed between each of the cores. The electromagnet cores and the biasing permanent magnets are in direct contact such that only a minute gap exists at a junction therebetween. A viscous material, adhesive material, or a magnetic fluid such as grease, having therein a material having high permeability and high saturation magnetic flux density is disposed in the minute gap so as to minimize magnetic flux leakage at the junction.

Abstract: A device for detecting a bending magnitude of a rotary shaft comprises a first pair of coils spaced from and facing the outer surface of a shaft and having an inductance value, and a second pair of coils spaced from and facing the outer surface of the shaft and connected in series to the first pair of coils at respective nodal points. The second pair of coils has an inductance value different from the inductance value of the first pair of coils. A pair of high frequency oscillators applies a high frequency voltage across the first and second pairs of coils to generate at each of the nodal points an output signal corresponding to a bending magnitude of the shaft, each output signal having a constant linearity characteristic resulting from the difference in inductance value between the first and second pairs of coils. An amplifier is connected to each of the nodal points for amplifying the output signals from the nodal points.