Scroll fluid machine having an orbiting radius varying mechanism and a clearance between the wrap portions

摘要

A fixed scroll member has a spiral wrap portion. An orbiting scroll member has a spiral wrap portion similar to the wrap portion of the fixed scroll member. The wrap portion of the orbiting scroll member has its wall thickness increased at the inner peripheral surface side thereof to have a larger wall thickness than that of the wrap portion of the fixed scroll member. The inner peripheral surface of the wrap portion of the orbiting scroll member contacts the outer peripheral surface of the wrap portion of the fixed scroll member at two contact points. On the other hand, a clearance is formed between the outer peripheral surface of the wrap portion of the orbiting scroll member and the inner peripheral surface of the wrap portion of the fixed scroll member over the entire length of the peripheral surfaces. The orbiting scroll member is constantly urged in a direction in which rotational torque acts, and thus allowed to orbit smoothly.