A hydraulic valve is an element used to control the pressure, flow, and direction of fluid in a hydraulic system.
First, Classification
1. According to the function, it can be divided into pressure control valve, flow control valve and directional control valve. Pressure control valves are used to control the pressure in the system, such as relief valves, pressure reducing valves, etc. Flow control valves are used to regulate the flow in the system, such as throttle valves, speed control valves, etc. Directional control valves are used to change the flow direction of fluids, such as check valves, reversing valves, etc.
2. According to the structural form, it can be divided into spool valve, pop valve, ball valve, etc.
Second, the working principle
Hydraulic valves control the flow direction, pressure, and flow of hydraulic oil by changing the relative position between the spool and the seat. When the valve core is affected by external control signals (such as electromagnets, mechanical forces, etc.), the corresponding displacement will be generated, which will change the opening and flow area of the valve port to achieve the control of the hydraulic system.
Third, the field of application
It is widely used in construction machinery, metallurgical equipment, mining machinery, injection molding machinery, ships, aerospace and other fields. For example, in construction machinery, hydraulic valves are used to control the lifting, luffing and slewing of cranes; In injection molding machinery, hydraulic valves are used to control the processes of mold clamping, injection, pressure packing, and demoulding of injection molding machines.
Fourth, features
1. High control accuracy: It can accurately control the pressure, flow and direction of the hydraulic system.
2. Fast response: It can quickly respond to the control signal and realize real-time control of the hydraulic system.
3. High reliability: It has good sealing performance and anti-pollution ability, and can operate stably for a long time in harsh working environments.
4. Compact structure: small size, light weight, easy to install and maintain.
5. Troubleshooting methods for hydraulic valves
Troubleshooting pressure control valves
1. Relief valve failure
The pressure cannot be adjusted: check whether the spring is damaged or deformed, whether the valve core is stuck, and whether the damping hole is blocked. If there is a problem with the spring, replace the spring; If the valve core is stuck, the valve core and valve body need to be cleaned; If the damping hole is blocked, clean the damping hole.
Large pressure fluctuations: It may be that the spool is not well matched with the seat or there are impurities in the oil. The spool and seat can be grinded, the hydraulic system can be cleaned and the fluid can be replaced.
Severe leakage: Check the seal for damage, and replace the seal if it is damaged.
2. Failure of the pressure reducing valve
Unstable outlet pressure: Check if the spool is stuck and if the spring is failing. The treatment method is the same as the corresponding fault of the relief valve.
Leaks: Check the seal and replace the damaged seal.
Flow control valve troubleshooting
1. Throttle valve failure
Flow regulation failure: Check whether the valve core is stuck and whether the throttle is blocked. Clean the spool and throttle.
Leaks: Check the seals and replace the damaged ones.
2. The speed control valve is faulty
Unstable speed: It may be that the gap between the spool and the valve sleeve is too large, the spool spring of the pressure reducing valve is failing, etc. Parts need to be repaired or replaced.
Directional control valve troubleshooting
1. Check valve failure
Reverse Leak: Check the seal, replace the damaged one.
No one-way action: the spool is stuck by impurities or the spring is damaged, clean the spool or replace the spring.
2. Failure of the reversing valve
Non-reversing: Check whether the solenoid is damaged, whether the valve core is stuck, and whether the control oil circuit is blocked. Repair or replace the solenoid, clean the spool and control oil circuit.
Inadequate reversing: Adjust the spool stroke or check if the spring is suitable.
types of hydraulic valves
What is a hydraulic valve