Hydraulic control valve classification and working principle analysis

Hydraulic control valves are components of the hydraulic system that control the direction, pressure, and flow of oil. By means of these valves, the start, stop, direction, speed, sequence of actions and the ability to overcome the load of the actuator can be controlled and adjusted so that all types of hydraulic machines can work in harmony as required.

Hydraulic valve classification

A [by application]

Hydraulic valves can be divided into directional control valves (such as check valves and directional valves), pressure control valves (such as relief valves, pressure reducing valves, and sequence valves, etc.) and flow control valves (such as throttle valves and speed control valves). ). The three types of valves can also be combined with each other to form a combination valve, such as a one-way Sichuan page sequence valve, a one-way throttle valve, an electromagnetic relief valve, etc., making it compact, simple to connect, and improving efficiency.

B [by working principle]

Hydraulic valves can be divided into on-off valves (or on-off valves), servo valves, proportional valves, and logic valves. After the on-off valve is set, it can only work in the set state. This chapter will focus on the most commonly used valves. Servo and proportional valves can continuously or proportionally control system data based on the input signal. The logic valve controls the action of the actuator according to a preprogrammed logic program.

C [by installation connection type]

According to the installation connection, hydraulic valves can be divided into:

(1) Screw type (tube type) mounting connection. The port of the valve is connected to the pipe fittings and pipes and other components and is thus fixed on the pipe. This method is suitable for simple hydraulic systems.

(2) Screw mounting connections. The oil ports of the valve are all arranged on the same mounting surface, and are screwed on the connecting plate with the corresponding oil port of the valve, and then the pipe joint and the pipe are connected with other components; or the several valves are screwed on one Integrated block

On the different sides, holes are drilled in the manifold and the valves communicate with each other. Since the disassembly of the valve does not require disassembly of other components connected thereto, this type of mounting connection is widely used.

(3) Stacked mounting connections. The upper and lower sides of the valve are connecting joint surfaces, and the oil ports are respectively on the two surfaces, and the oil outlet connection dimensions of the valves of the same specifications are the same. Each valve, in addition to its own function, also functions as an oil passage, and the valves are stacked one on another to form a circuit without the need for pipe connections. Therefore, the structure is compact and the resistance loss is small.

(4) Flange mounting connection. Similar to the screw-type connection, only the flange type replaces the screw fitting. Used for path! 32_ large flow system. Its high strength and reliable connection.

(5) Plug-in mounting connections. There is no separate valve body for this kind of valve, and the unit body consisting of the valve core, the valve sleeve and the like is inserted into the prefabricated hole of the insert block, fixed by a connecting screw or a cover plate, and each plug-in valve is passed through the internal channel of the block. The connection constitutes a loop, and the insertion block functions as a valve body and a pipeline. This is a new type of mounting connection that has been developed to accommodate the integration of hydraulic systems.