Abstract: Aimed at the problem of tangential leakage caused by kinematic pair clearance in scroll compressor with autorotation prevention mechanism of crankshaft pin and based on the parallel four-bar linkage model simplified with principle of mechanism, a mechanism with clearance in itself is converted into one with multiple components, multiple degrees of freedom and no gap, and analyzed there after, so that the influence of the clearance magnitude at anti-rotation crank pin on the autorotation angle and tangential leakage gap is determined with the help of Matlab numerical analysis software. The results show that the autorotation of the movable scroll disk will make the magnitude of leakage gap to change periodically with the rotation angle of the spindle and increase with the increase of the gap magnitude. The amount of change of the negative gap caused by the reverse rotation will make the wear of the movable and static scroll teeth increased. Therefore in the design stage of the compressor, the fitting tolerances should be strictly selected to reduce the adverse effect of the fitting clearance.

Key words: scroll compressor, kinematic pair, clearance, parallel four-bar linkage