The speed control valve is composed of three parts: a hydraulic reversing valve, a simple throttle valve and a fixed differential pressure reducing valve. When the oil cylinder stops running, there is no oil flowing through the speed control valve, the pressure reducing valve is in a fully open state, and the hydraulic reversing valve is in a closed state. When restarting, the hydraulic oil must first open the hydraulic directional valve. At the same time, because the oil pressure in the spring chamber of the pressure reducing valve is very low, the pressure reducing valve is lifted, the valve port is closed, and the flow through is small. When the oil pressure of the oil cylinder is established, the pressure of the upper and lower chambers of the pressure reducing valve core gradually reaches a balance to maintain an appropriate opening, which plays a role of speed regulation together with the throttle valve at the back. Therefore, there is no forward rush phenomenon.

Application and principle of speed control valve

It consists of a fixed differential pressure reducing valve, an electromagnetic reversing valve and two simple throttle valves. When the reversing valve is turned on at the upper position, the passing flow is adjusted by the valve, and when the reversing valve is turned on at the lower position, the passing flow is adjusted by the valve. The two work advance speeds can be adjusted separately. When one type of work advance is transferred to another type of work advance, when the pressure reducing valve is always in a decompression state, the cylinder will not appear forward. And the speed adjustment of this loop is flexible and convenient. The circuit has less heat and high efficiency.

The structure of the new speed control valve is that two throttle valves share a fixed differential pressure reducing valve, and a reversing valve is embedded between the fixed differential pressure reducing valve and the two throttle valves. Compared with a speed switching circuit composed of a reversing valve, it greatly reduces the occupied space and simplifies the circuit. The speed control performance is the same as the ordinary speed control valve, but the speed changeover performance is significantly improved. This new type of speed control valve is especially suitable for occasions where the integrated size of the wave pressure system is restricted. The new speed control valve and the new speed control valve overcome the shortcomings of the previous speed control valve throttling speed control circuit and I feed speed switching circuit, and have broad development prospects in hydraulic machine tools.