Variable capacity piston machine with reduced noise and vibration by reducing pulsation of discharged fluid

摘要

Provided is a variable displacement piston machine capable of reducing fluctuations in the amount of hydraulic fluid flowing out from a high-pressure port to a low-pressure port and a drain to reduce pulsation of discharged fluid, thereby reducing noise and vibration. The intermittent drain passage 5 is provided on the sliding surface 1a of the valve plate 1 so as not to directly communicate with the high pressure port 3a and the oil groove 4. The intermittent drain passage 5 communicates with the high pressure port 3a and the cylinder port 54a through the coupling groove 4 and when a reverse flow is generated from the high pressure port 3a to the cylinder port 54a, (3a) and the cylinder port (54a). In this state, when the cylinder block 55 further rotates, the intermittent drain passage 5 communicates with the high-pressure port 3a through the cylinder port 54a.