VARIABLE DISPLACEMENT PISTON MACHINE FOR REDUCING NOISE AND VIBRATION BY REDUCING PULSATION OF DISCHARGE FLUID

摘要

A variable displacement piston machine is provided for reducing noise and vibration by reducing the pulsation of discharge oil by reducing in turn the change in volume of operation fluid flowing from a high pressure port to a low pressure port and a drain. An intermittent drain path (5) is formed in a sliding surface (1a) of a valve plate in such a manner that it does not directly communicate with a high pressure port (3a) and an oil guide groove (4). This intermittent drain path (5) does not communicate with the high pressure port (3a) and a cylinder port (54a) while there is occurring a reverse flow from the high pressure port (3a) to the cylinder port (54a) with the high pressure port (3a) communicating with the cylinder port (54a) via the oil guide groove (4a). When a cylinder block (55) rotates further from that state, the intermittent drain path (5) communicates with the high pressure port (3a) via the cylinder port (54a).