Effect of atrial fibrillation on the dynamics of mitral annular area.

In a scroll type machine, such as a scroll compressor, the difference in level between the axial end surface of a wear-resistant plate (40) installed at the periphery of the end plate (17) of an orbiting scroll (16) and the axial end surface of the end plate (17) is set within 0+/-10 mu m. This difference in level ( delta ) is set to this range to prevent wear of the wear-resistant plate and the end plate of the orbiting scroll and to prevent deterioration in the performance of the scroll-type compressor so that a scroll-type compressor with high performance and high reliability can be realized.