1. Preparation
①All hydraulic components are very delicate 名媛直播, so before disassembling, you must choose a clean workplace.
② When disassembling the control valve of a modern excavator, pay attention to prevent foreign objects such as dust and sand from entering the valve body.
③ When the control valve is removed from the machine, seal all the oil ports with a cover. Before disassembling the valve, check again that these covers are all installed, and then clean the outside of the valve. Use a suitable workbench with rubber pads on it before disassembly.
④ When transporting or transferring the control valve, pay attention to lifting the support part of the valve with a crane, and do not directly lift the spool or end cover and other unstable places.
⑤When disassembling parts, you need to test these parts with hydraulic test equipment (such as testing overflow pressure, oil leakage, oil flow, etc.), do not disassemble those parts that cannot be tested and adjusted, and be prepared to clean before work Agents, grease, etc.
2. Disassembly of the main control valve
(1) Rotate the control valve on the workbench to disassemble the valve in a clean and dry working environment, taking care not to damage the sealing flange surface.
(2) Straight travel valve body Loosen the hexagon bolts and remove the straight travel valve body.
(3) Main spool
① Loosen the hexagon bolts and remove the spring cover.
②Remove the spool, spring, stop block, spring seat and spacer screw in the spool.
When removing each spool assembly from the housing, be careful not to damage the housing.
(4) Cover Loosen the hexagon bolts, and then remove the valve cover.
(5) Remove the port relief valve. Remove the port relief valve from the housing.
(6) Remove the plug (optional) Remove the plug from the housing.
(7) Locking valve Loosen the hexagon bolt and remove the locking valve
(8) Negative control relief valve
①Remove the plug
②Remove the spool, spring and rod.
(9) Rotary logic valve and check valve
① Loosen the hexagon bolts and remove the logic valve and check valve.
②Remove the plug and remove the spool and spring
(10) Boom priority valve Loosen the hexagon bolts and remove the boom priority valve.
(11) After cleaning, clean all parts with a cleaning agent and blow dry with compressed air, and then place them on clean paper or cloth for easy detection.
①Check the control valve:
A. Check all parts for roughness, scratches, dents and other damage.
b. Confirm whether the surface of the sealing groove of the housing and the housing are smooth, whether there is dust, dents, rust, etc.
C. Correct dents and damaged parts and check whether the seat is stable
D. Be careful not to leave any foreign objects in the valve housing
E. Make sure that all sliding parts can be moved manually, and that all grooves and slides are free of foreign objects.
F. If the spring is damaged or deformed, replace it with a new spring.
G. When the overflow valve does not work properly, repair the overflow valve and replace all seals and O-rings
②Check the relief valve
a. Confirm whether all the valve seats are damaged or whether they match the valve core.
B. Is it easy to slide the main spool and seat by hand.
C. Confirm that there is no scratch on the outer surface of the main spool and the inner surface of the valve seat.
D. Confirm that the spring is not damaged, deformed and fatigued.
E. Make sure that the main valve core orifice and valve seat are not blocked by foreign objects. f. Replace all O-rings.
G. Check and correct any minor damage. h. When the overflow valve is abnormal, replace it with a new one.
3. Installation of the main control valve Note the following when installing the main control valve
①Be careful not to damage the seals, and check carefully before use.
②Apply clean grease and hydraulic oil to the seal to ensure that the seal is fully lubricated before installation.
③Do not stretch the seals too much to avoid permanent deformation
④When installing the O-ring, pay attention to lay the O-ring flat and do not curl. The curled O-ring cannot play a sufficient sealing effect, resulting in leakage of internal and external oil.
⑤ Use a torque wrench to tighten the mounting bolts of each part according to the corresponding tightening torque.
Install in the reverse order of disassembly.
①Install check valve.
2 Install negative control relief valve.
③ Install the lock valve.
④ Install the main relief valve and port relief valve.
⑤ Install the main spool.
⑥Install the bonnet
⑦ Install linear travel valve, rotary logic valve and boom priority valve.
