Proportional flow valve controlled by pilot flow closed loop

Abstract

The invention relates to a proportional flow valve controlled by a pilot flow closed loop, which is provided with a flow sensor consisting of a two-position two-way cartridge valve. The control cavity of a main valve is communicated with the oil inlet of a pilot valve; the oil inlet of the flow sensor is communicated with the oil outlet of the pilot valve; the oil outlet of the flow sensor is simultaneously communicated with the springless oil cavity of the pilot valve and the oil outlet of the main valve; the oil outlet of the flow sensor is communicated with the control cavity of the flow sensor through a damping hole; the control cavity of the flow sensor is communicated with the spring oil cavity of the pilot valve; the valve core of the flow sensor, the valve core of the pilot valve and a flow sensor spring are coaxially arranged; and one end of the flow sensor spring acts on the core end of the pilot valve, while the other end acts on the valve core end of the flow sensor. The proportional flow valve can obtain seven technical schemes by changing communication relations. The proportional flow valve comprises an innovative idea that the flow of the pilot valve is detected by a minitype flow sensor, the flow of the pilot valve is controlled in the way of forming the closed loop and the flow of the main valve is amplified according to a Valvistor valve amplification principle. The proportional flow valve has the advantages of combining two control principle structures of flow closed loops and flow amplification and has the characteristics of simple structure, high flow control precision and high efficiency.

Description

technical field [0001] The invention belongs to a two-way proportional flow valve, more specifically, a two-position two-way proportional flow valve for continuous electro-hydraulic control of system flow. Background technique [0002] The two-way proportional flow valve is an element in the electro-hydraulic control system that continuously controls the flow supplied to the hydraulic actuator. According to the flow equation of the valve port, the flow through the valve is not only proportional to the opening area of ​​the valve port, but also influenced by the two ports of the valve port. The effect of the change in the terminal pressure difference. Therefore, the most commonly used two-way proportional flow valve to control the flow is to connect a pressure difference compensator in series at the inlet or outlet of the proportional throttle valve that controls the opening area of ​​the valve to keep the pressure difference at both ends of the proportional throttle valve co...

AI Technical Summary

Problems solved by technology

[0005] The present invention improves the proportional flow valve in the prior art, and the problems to be solved are: (1) under the influence of hydraulic power, the pressure difference compensator installed on the main oil circuit has low control accuracy and large throttling loss; (2) Although the flow sensor is installed on the oil circuit, the control accuracy is improved, but the structure of the valve becomes very complicated, which increases the difficulty of valve manufacturing; (3) the cost of electronic closed-loop correction of the pressure sensor is high; (4) the existing Valvistor valve, although Only a small flow pressure differential compensator is required to compensate the differential pressure of the pilot valve, which simplifies the structure of the valve, but the flow rate of the pilot valve is still open-loop control, which affects the control accuracy of the entire valve

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