An Analytical Study on the Kinematics of Orbiting Scroll in Scroll Compressors

Abstract

Scroll compressors having orbital mechanisms composed of a ball coupling and an eccentric bushing are successfully used for automotive air conditioners. The mechanism is essential for high performance and high reliability of the compressor, but its ability to restrain rotational displacement of an orbiting scroll is not perfect because of some clearance that exists at the ball coupling. This paper focused on the kinematics of the orbiting scroll supported by the ball coupling and the eccentric bushing. Forces acting on members of the compressor were analyzed theoretically and the causes of the rotational displacement of the orbiting scroll were examined. The analysis revealed that periodic self-rotation of the orbiting scroll occurs within the tolerance limit of the ball coupling during one revolution of the compressor. The tendency was confirmed experimentally by monitoring rotational motion of the orbiting scroll with a high-speed video camera.