The function is to use the joint action of hydraulic pressure and spring force to control the separation or contact of electrical contacts in the hydraulic system control, so as to convert the hydraulic signal into electrical signal, make the electrical components act, realize automatic control, and play the role of interlocking protection.
Common faults and troubleshooting of pressure relay of Kobelco excavator are as follows.
(1) Unqualified output or no output
① The microswitch is damaged. Replace.
② Electrical circuit failure. Check the cause and eliminate the fault.
③ The valve core is stuck or the damping hole is blocked. Cleaning and repair.
④ The oil inlet pipe is bent and deformed, so that the oil flow is not smooth. Replace the pipe.
⑤ The adjusting spring is too hard or the pressure is adjusted too high. Replace the appropriate spring or adjust the pressure value as required.
⑥ There is oil leakage at the pipe joint. Tighten the connector to eliminate oil leakage.
⑦ The contact connected with the microswitch is not adjusted properly. Readjust carefully to make the contact point good.
⑧ The spring and lever are poorly assembled and stuck. Reassemble to make the movement sensitive.
(2) Poor sensitivity
① The friction at the lever pin is too large, or the friction at the contact between the steel ball and the plunger is too large. Check the machining accuracy of components and reassemble them to make them sensitive.
② Microswitch contact travel is too long. Adjust the position reasonably.
③ Improper adjustment of contact screws, levers, etc. Reasonably adjust the position of screws and levers.
④ The valve core moves inflexibly or "do not force" to repair, assemble or clean again.
(3) Signal too fast
① The oil inlet damping hole is too large. Appropriately reduce the damping hole, or add a damping pipe on the control pipeline.
② The diaphragm is broken. Replace the diaphragm.
③ The impact pressure of the system is too large. Add a damping pipe on the control pipeline to reduce the impact pressure.
④ The electrical system design is wrong. Design the electrical system according to the process requirements.
