Valve plate and hydraulic apparatus with the same

Abstract

Provided an efficient valve plate capable of keeping noise low and a hydraulic device provided with the same. A pressure release port 33 including a first and a second pressure release hole 34, 35 is formed on an upstream side of a rotary direction A20 of a cylinder block 22 in relation of an intake port 31 on the valve plate 21. The pressure release port 33 opens a cylinder port in multiple steps, and discharges working fluid in a piston chamber 37 before the piston chamber 37 is connected to the intake port 31. Consequently, jet is prevented from occurring when the piston chamber 37 is connected to the intake port 31, noise can be prevented and cavitation damage of the valve plate 21 can be prevented.

Description

technical field [0001] The present invention relates to a hydraulic device suitable as a valve plate realized by a piston pump and a piston hydraulic motor, and particularly relates to a valve plate provided in the hydraulic device. Background technique [0002] Figure 7 is a front view of the valve plate 2 of a prior art piston pump. Figure 8 From Figure 7 A cross-sectional view of a part of the piston pump obtained by observing section line S8-S8. Figure 8 The upper development represents an arc-shaped cross section extending in the circumferential direction. The piston pump includes a cylinder block 5 provided rotatably in a rotation direction A1 around an axis L1. A plurality of piston chambers 6 are formed in the cylinder block 5 , and cylinder ports 7 communicating with each of the piston chambers 6 are respectively formed. A piston 8 is fitted into each piston chamber 6 . A brake shoe is provided at one end of each piston, and each brake shoe is pressed agains...

AI Technical Summary

Problems solved by technology

In this state, when the opening area of ​​the suction port 3 is large, the efficiency of the pump decreases due to the large flow rate flowing in the reverse direction from the discharge port 4 to the suction port 3, and the pressure fluctuation rate of the piston chamber 6 is large. thus increasing the vibration

In addition, when the opening area of ​​the suction port 3 is relatively small, if the pressure difference between the cylinder port 7 and the suction port 3 is relatively large for a relatively small opening area, the flow rate of the working oil flowing in the reverse direction increases, resulting in The jet flow produces a large noise and causes damage to the valve plate 2 and the cylinder port 7

Also, in the case where the suction port 3 and the discharge port 4 are not connected by the cylinder port 7, after the discharge port 4 and the cylinder port 7 are cut off, the working oil in the piston chamber 6 is compressed by the piston 8, and the pressure of the working oil When the pressure becomes high, more noise occurs due to the connection with the suction port 3, and the valve plate 2 and the cylinder port 7 are obviously damaged.

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