Abstract: A scroll fluid machine requiring no crank shaft to orbitably support an orbiting scroll member and capable of being reduced in overall size in the axial direction. In a casing, two fixed scroll members are provided on the axis of the casing, and an electric motor is provided between the fixed scroll members. Eccentric bearings each having an outer ring, an intermediate ring and an inner ring are provided between the electric motor and the fixed scroll members. The inner periphery of each intermediate ring is formed with an axis eccentric with respect to the axis of the casing. Orbiting scroll members are integrated with the inner rings through an orbiting shaft. The orbiting shaft is caused to orbit by rotating a rotating shaft with the electric motor, thereby causing the orbiting scroll members to orbit relative to the fixed scroll members.

Abstract: A screw compressor having a recess formed in the high-pressure end surface of the casing. This recess receives the fluid from a closed working space which has just been isolated from the discharge port and closed in the compression step. Consequently, the abnormal pressure rise in the closed working space, which is caused due to the compression of the fluid confined, is completely eliminated. The recess has a configuration involving a curve conforming with the leading flank of the female rotor at the instant at which the working space is isolated from the discharge port and closed.