Abstract: In a rotary vane-type compressor the rotor, the housing and the side plates are made of the same kind of material as one another. A plurality of vane grooves the length of each of which is as long as the thickness of the rotor is provided on the rotor. A set of vanes which is made of a different material than the rotor, more particularly a material the coefficient of thermal expansion of which is larger than that of the rotor, is received in the vane grooves in such manner that the end faces thereof face against the side plate. And the width of the vanes longitudinally of the rotor is determined as follows. The width is slightly less than the thickness of the rotor when the temperature there of is less than normal, but when the temperature becomes high the vane width becomes slightly greater than the thickness of the rotor because of the difference of the coefficients of thermal expansion.

Abstract: A rotor cover is disposed at one end surface of a rotor which has a ring-shaped locking ridge on the end surface thereof. The locking ridge has an outer peripheral surface fitted in a locking groove in the rotor cover. A holder is held against an inner peripheral surface of the locking ridge. With this arrangement, the diameter of the rotor is kept constant at all times, and so is the gap between the rotor and the housing, thus preventing scuffing of the rotor and the housing.