Pressure stop valve of hydraulic variable displacement motor

Abstract

The invention discloses a pressure stop valve of a hydraulic variable displacement motor. The pressure stop valve comprises a valve body with a valve cavity and a valve rod inserted to the valve body. One end of the valve rod is provided with a reversing spring and is communicated with an oil tank. The valve cavity is provided with a working oil opening, a high pressure opening and an oil returning opening. The working oil opening is communicated with a large cavity of a variable displacement cylinder of the hydraulic variable displacement motor. The high-pressure opening is communicated with a small cavity of the variable displacement cylinder. The oil returning opening is communicated with the low-pressure end of the valve rod. When the valve rod moves, the communication state of the working oil opening and the oil returning opening or the high-pressure opening is changed, a groove is formed in the other end of the valve rod in the periphery direction, and the groove is communicated with the high-pressure side of the hydraulic variable displacement motor through an inlet damping component and is communicated with the oil tank through a bypass damping component. Accordingly, the action area of valve rod reversing pressure is decreased, reversing impact is lowered, the valve rod can operates stably, and intermittent shaking of the hydraulic variable displacement motor caused by the fact that valve rod response is too sensitive is avoided.

Description

technical field [0001] The invention relates to the field of hydraulic technology, in particular to a pressure cut-off valve of a hydraulic variable motor. Background technique [0002] When the crane is hoisting, the weight of the heavy objects is different each time. It is usually hoped that the heavy objects can be lifted when the heavy objects are heavy. According to the requirements of the working conditions, the hoisting mechanism of the crane is generally driven by a variable motor. [0003] At present, a variable variable motor commonly used in the market is HD1D (hydraulic control, pressure cut-off) variable variable motor. When this variable variable motor is working, the motor displacement changes from large displacement to small displacement, and the working pressure of the motor increases gradually. When the set pressure is reached, the pressure needs to be cut off to increase the displacement of the motor until it matches the working pressure of the system. S...

AI Technical Summary

Problems solved by technology

[0011] The action area of ​​the pressure cut-off valve 100 for the reversing pressure is relatively large, which is the left end surface of the valve stem 102, which makes the valve stem 102 unstable during operation and has a large reversing impact; as long as the pressure at the high pressure end of the valve stem 102 fluctuates, the valve stem will 102 responds immediately and moves back and forth, which not only reduces the stability of the pressure cut-off valve 100, easily causes intermittent vibration of the variable motor, but also increases the wear of the valve stem 102, reducing the service life of the pressure cut-off valve 100

[0012] In addition, since the valve port of the pressure cut-off valve 100 is covered by the neutral zero, during the reversing process of the valve stem 102, the pressurization and pressure relief of the working oil port M are faster, especially when the valve stem 102 moves to the left When the working oil port M is connected with the high-pressure port G, because the high-pressure port G is a high-pressure point, the working oil port M is easy to form an instantaneous pressure shock, which makes the pressure in the large chamber of the variable cylinder 200 fluctuate greatly, resulting in the variable piston 201 not moving. smooth

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