Mixed Lubrication Analysis of Vane Sliding Surface in Rotary Compressor Mechanisms

In the compression mechanisms of a rotary compressor for air conditioners, a vane and a rolling piston are provided to separate the suction chamber and the compression chamber. The rolling piston is driven by the crank, and revolves on the axis of the shaft eccentrically, and also rotates on its own axis. The vane undergoes reciprocating motion, and its top usually comes into contact with the rolling piston by the spring force and the discharge pressure. The lubricating condition between the vane top and the rolling piston is severe because the contact pressure is high owing to the line contact of the vane top. For the prevention of scuffing, abnormal wear and so on, it is important to clarify the lubricating characteristics between the vane top and the rolling piston. Because the normal force acting on piston at vane contact is greatly influenced by the friction of vane sliding surface between the vane and the vane-slot, a mixed lubrication analysis of the vane sliding surface between the vane and the vane-slot is required to obtain the normal force acting on piston at vane contact accurately. In order to investigate the lubricating characteristics between the vane top and the rolling piston, a numerical analysis of the motion of the rolling piston and the motion of the vane considering the mixed lubrication of the vane sliding surface has been performed. The cases of different friction coefficient of the vane sliding surface at solid contact were calculated, and the results were compared. As a result, the effects of the friction of the vane sliding surface on the lubricating characteristics between the vane top and the rolling piston have been made clear