| 摘要 |
PURPOSE: To reduce noises generated from a fluid pressure actuated device, mainly those caused by a secondary piston frequency, by providing cylinder ports with leading edges disposed randomly relative to the imaginary axes of cylinders. CONSTITUTION: Each cylinder port 47 is provided with a leading edge in a certain position in the instantaneous direction of rotation of a cylinder block 25 and the leading edge is disposed at a different distance from the imaginary axis (a) of a cylinder 27 corresponding to its respective cylinder port 47 than leading edges provided at the circumferentially adjacent cylinder ports 47. Kidney ports 47a-47i, for example, are not located in the same circumferential position relative to the respective cylinders 27a-27i; that is, the kidney port 47a is in an almost 0-lap condition relative to the corresponding cylinder 27a, while the following kidney port 47b has its leading edge advanced from the corresponding cylinder 27b in the direction of rotation of the cylindrical block 25. |
