| 摘要 |
PROBLEM TO BE SOLVED: To prevent the end of a bush at the side of a cylinder chamber from coming in linear contact with a blade by devising the shape of the bush.SOLUTION: A bush (61) on the low pressure side slides with the circular arc face of the bush (61) being pushed against the side of a cylinder chamber (55) in a bush groove (63) by a differential pressure between a low pressure on the side of the cylinder chamber (55) and a high pressure in a back pressure space (64) opposed to the cylinder chamber (55) across the bush (61). On a flat face (61a) of the bush (61) on the low pressure side, a crowning part (65) is provided. The crowning part (65) is a part which is subjected to crowning work in a range from a starting position nearer the back pressure space (64) than a center position (O) of rocking to the end on the side of the cylinder chamber (55). The center position (O) of rocking is a position where a clearance between a blade (62) and the bush (61) becomes constant during the eccentrically rotating motion of a piston (60).SELECTED DRAWING: Figure 3 |
