Relief valve
1. The system pressure can not be added completely. The reasons are: the damping hole of the spool is blocked, the assembly quality is poor, and the spool is damaged by the spring. Elimination method: clean the damping hole, replace the spring.
2. The system pressure does not rise high because of spool wear and leakage. Elimination method: Replace the spool.
3. The reason for the sudden rise or fall of pressure: the spool action is not sensitive, and the spool damping hole is blocked. Elimination method: clean the valve body and damping hole.
Reversing valve fault
1. The spool cannot move causes:
1) The surface of the spool is scratched and the spool is blocked.
2) The valve core and the valve body internal hole with improper clearance, clearance large spool easy skew, spool stuck; Small clearance spool resistance is large, spool can not move.
3) The spring is too soft to push the spool; The spring is too hard to push the spool in place.
4) The electromagnet is damaged. Elimination method: restore the spool or replace the spool; Check the fit clearance; Replace the spring.
2. Electromagnet coil burns out cause: electromagnet damage; Excessive oil viscosity; Exposed external coil, short circuit burned; The voltage is too high. Elimination method: replace the electromagnet; Filter oil or replace hydraulic oil; Wrap up the external coil and replace the electromagnetic coil; Adjust the voltage.
3. Cause of external leakage: the sealing ring is damaged; The screw is loose. Elimination method: replace the sealing ring; Tighten the screws.
Hydraulic valve repair method
The significance of hydraulic valve maintenance is not only to save the cost of component acquisition, when the failed hydraulic valve has no spare parts or needs a long time to order, and the equipment may be shut down for a long time through maintenance can temporarily maintain the operation of the equipment and even the entire production line, its economic benefits are quite considerable. In the practice of hydraulic valve maintenance, the commonly used repair technology includes hydraulic valve cleaning, parts combination selection, repair size and so on.
1.The details are as follows:Hydraulic valve cleaning disassembly cleaning is the first process of hydraulic valve maintenance. For the hydraulic valve failure caused by hydraulic oil pollution or granular impurities in hydraulic oil, the fault can be eliminated by disassembly and cleaning, and the function of the hydraulic valve can be restored.
Common cleaning processes include: 1) disassembly. Although most of the parts of the hydraulic valve are bolted, the hydraulic valve is designed for non-disassembly. If there is no special equipment or professional technology, forced disassembly is likely to cause damage to the hydraulic valve. Therefore, the structure of the hydraulic valve and the connection between the parts should be mastered before disassembly, and the position relationship between the parts should be recorded during disassembly. 2) Check and clean up. Check the fouling deposition of valve body, valve core and other parts. Under the premise of not damaging the working surface, use cotton yarn, brush and non-metallic scraper to remove concentrated dirt.
3) Rough wash. Put the valve body, valve core and other parts on the tray of the cleaning box, heating and soaking. The compressed air is passed into the bottom of the cleaning tank, and the remaining dirt is cleaned by the agitation of the bubble. If possible, ultrasonic cleaning can be used.
4) Fine washing. High pressure positioning cleaning with cleaning solution, and finally dry with hot air. Qualified enterprises can use the existing cleaning agents, individual occasions can also use organic cleaning agents such as diesel, gasoline.
5) Assembly. Assemble according to the hydraulic valve assembly diagram or the parts assembly relationship recorded during disassembly. Be careful not to damage the parts during assembly. The original sealing material is easy to be damaged during disassembly and should be replaced during assembly.
2. The hydraulic valve manufacturing process, in order to improve the assembly accuracy of the selection method, that is, to a number of processed parts, such as the valve body and the valve core, according to the actual size of the selection of the most appropriate clearance with a pair of assembly, in order to ensure good valve core sliding and sealing performance. That is to say, the same type of hydraulic valve, the size of the spool and the valve body has a certain difference. For enterprises, when the number of a certain type of failed hydraulic valve is large, all the valves can be disassembled and cleaned, all the parts can be checked and measured, the parts can be classified according to the test results, and the parts can be re-combined and matched according to the following methods. If the valve core and valve body belong to uniform wear, the working surface is not seriously scratched or local serious wear, in accordance with the relevant manual, choose the valve core with appropriate clearance, valve body reassembly; If the spool, valve body wear is not uniform or the working surface is scratched. Through the above method has not been able to restore the function of the hydraulic valve, choose to meet the processing allowance requirements of a pair of interference of the valve core, the valve body (small hole size of the valve body and the outside diameter size of the valve core), the valve hole is hinged or grinding, grinding the valve core, to achieve a reasonable shape precision with precision assembly.
