(A) composite function stack valve
Composite function stacked valve is a control spool in a control valve to achieve more than two kinds of control functions of the hydraulic valve.
1. Sequence throttle valve
Stacked sequence throttle valve is a composite valve consisting of a sequence valve and a throttle valve, with two functions of sequence valve and throttle valve. Integral structure, by the valve body 1 piece, spool 2 pieces, throttle valve adjustment lever 3 pieces, sequence valve spring 4 pieces. Sequence and throttle valves share a common spool, and a triangular grooved throttling port is set at the control edge of the sequence spool. The throttle port opens and closes with the opening and closing of the control port of the sequence valve, and the opening and closing of the throttle port depends on the size of the sequence valve control oil line pressure A. The throttle port can be opened or closed when the sequence valve control oil line pressure A is greater than that of the sequence valve. When the pressure in line A is greater than the setting value of the sequence valve, the throttle port opens; when the pressure in line A is less than this value, the throttle port closes. It can be used in hydraulic systems with centralised oil supply for multiple circuits to solve the problem of pressure interference among the actuators at work.
Taking the multi-cylinder hydraulic system as an example, when the system is working, the pressure interference between the cylinders is mainly due to the fact that any hydraulic cylinder in the working process goes from working feed to rapid descent, resulting in a sudden drop in the system oil supply pressure, which leads to insufficient feeding force for other actuators and affects the machining accuracy. However, in such a system, if a sequential throttle valve is used, when a hydraulic cylinder goes from working feed to rapid descent, at the instant of changeover of the reversing valve, and before the connection of oil lines P and B, due to the drop in pressure of oil line A, the throttle port of the sequential throttle valve closes prematurely, keeping the pressure of the high-pressure source of oil Pi constant, so that it does not interfere with the normal work of the other hydraulic cylinders.
2. Electric one-way speed control valve
The valve consists of three parts: the speed control valve part I connected by plate type, the main part I of the stacked valve, and the pilot valve part I of plate type structure. The overall structure of the valve is a combination of structures, speed control valve part I can be used in common parts of the ordinary one-way speed control valve, high versatility.
The cone valve 10 in the main valve body 9 and the pilot valve 12 are used in the circuit for fast forwarding, work feeding, stopping or then fast returning in the work cycle. Fast forward, the solenoid is energised, the pilot valve 12 left, the d chamber and e chamber cut off, connected to the e chamber and f chamber, the cone valve spring chamber b oil through the e chamber, f chamber and superimposed valves back to the oil circuit T connected and unloaded. At this time, the cone valve 10 is opened under the action of the hydraulic oil in the a cavity, and the hydraulic oil goes from Al to A through the cone valve, making the circuit fast forward. When the work is fed, the solenoid is de-energised, the pilot valve is reset, and the hydraulic oil in the oil circuit Al goes to the b chamber through the d and e chambers, and the cone valve port is closed. At this time, the hydraulic oil entering from Al can only go to A through the speed control valve part, so that the circuit is in the working feeding state. When the circuit is turned to fast back, the hydraulic oil enters the valve from A, and the cone valve can be opened automatically to realise fast back.
(ii) Single-function superimposed valve
Hydraulic system single-function superimposed valve body has P, T, A, B four channels, so each valve according to its control point can have many different combinations, and ordinary single-function hydraulic valve is very different. The working principle and structure of single-function stack valves are similar to three kinds of ordinary hydraulic valves. The structure of the various valves in the single-function stack valve can be referred to the relevant product model series.
