In the hydraulic control system, the servo valve is a key component, and its performance directly affects the response speed, control accuracy and stability of the whole system. As a special hydraulic servo control element, jet tube servo valve has been widely used in aerospace, industrial automation and other fields because of its simple structure, strong anti-pollution ability and fast response speed. Among them, “frictionless” operation is an important characteristic of jet tube servo valve, which is of great significance to improve the performance of the system.
First, the basic structure and working principle of jet tube servo valve
Jet tube servo valve is mainly composed of nozzle, jet tube (control nozzle), receiving cavity and main valve core. Its working principle is to drive the main spool to move by changing the jet direction and controlling the pressure difference between the two sides of the receiving cavity, thus realizing the adjustment of the flow and pressure of the hydraulic system.
Compared with the traditional spool servo valve, the jet tube servo valve has no direct mechanical contact with the transmission parts, and the movement of the main spool is completely driven by hydraulic pressure. This structural design essentially avoids the occurrence of mechanical friction, thus realizing the “frictionless” operation characteristics.
Second, the key design of frictionless operation
1. Contactless signal transmission
The input signal of jet tube servo valve is transmitted by changing the direction of jet. This signal transmission mode does not need mechanical connecting parts, which avoids the friction caused by the contact between guide rod, slide valve and other parts in traditional valves.
2. Suspension design of main valve core
Under the action of the jet pipe, the main valve core realizes differential control through hydraulic pressure, and it is basically in a “suspended” state during its movement, maintaining a small gap with the valve body without direct contact, thus reducing mechanical friction.
3. Application of materials and surface treatment technology
Modern jet tube servo valves are made of materials with high hardness and wear resistance, such as ceramics and stainless steel, and the surface roughness is reduced by precision machining and surface coating technology, which further reduces the possible friction influence.
Third, the advantages of no friction
-Fast response: Friction-free design reduces the resistance when the spool moves, making the system respond more quickly.
-High positioning accuracy: the disappearance of friction improves the control accuracy, especially when small signals are input.
-Long service life and high reliability: no mechanical wear reduces the failure rate and prolongs the service life of the servo valve.
-Strong anti-pollution ability: simple structure, no precise sliding mating surface, so that it can still run stably in harsh working environment.
IV. Matters needing attention in practical application
Although the jet tube servo valve has the advantage of no friction, it is still necessary to pay attention to the cleanliness of hydraulic oil, temperature control and system pressure fluctuation during use to ensure its long-term stable performance.
tag
Through non-contact control mode and reasonable structural design, the jet tube servo valve effectively realizes “frictionless” operation, which provides a reliable guarantee for the efficient and accurate operation of the hydraulic control system. With the continuous progress of material science and fluid control technology, this kind of servo valve will play a more important role in the application field of high precision and high dynamic response in the future.