Excavator accessories hydraulic solenoid valve original TM68501 proportional solenoid valve

The solenoid valve on the hydraulic pump generally has two, one is the TVC solenoid valve, the other is the LS-EPC solenoid valve, the former is responsible for sensing the signal from the engine speed sensor, adjusting the engine power and the hydraulic pump power match, if damaged, either the engine is full of car, insufficient power, or the engine is difficult to start.
The latter is responsible for sensing the driver's operation and changes in the size of the external load, if damaged, it will cause weakness in digging, slow operation of the whole machine, poor micro-operation ability, and no high-speed gear. It should be noted that there is one TVC solenoid valve before and after the pump, and only one LS-EPC solenoid valve.
Hydraulic pump drive shaft can not withstand radial force and axial force, so it is not allowed to install belt wheels, gears, sprockets directly on the shaft end, usually with a coupling to connect the drive shaft and pump drive shaft.
If due to manufacturing reasons, the coaxial degree of the pump and the coupling exceeds the standard, and there is a deviation during assembly, the centrifugal force increases the deformation of the coupling with the increase of the pump speed, and the centrifugal force increases. Resulting in a vicious cycle, the result of vibration and noise, thus affecting the service life of the pump. In addition, there are other influencing factors such as coupling pin loosening and not timely tightenin

Excavator electromagnetic relief valve fault and troubleshooting method:

1. System pressure fluctuation

The main causes of pressure fluctuations are:
① The screws adjusting the pressure cause the locking nut to loosen due to vibration, resulting in pressure fluctuation;
② Hydraulic oil is not clean, there is a small dust, so that the main spool sliding is not flexible. Resulting in irregular pressure changes. Sometimes the valve will jam;
③ The main valve spool is not smooth, causing the damping hole to be blocked when it is through;
(4) The conical surface of the main valve core is not in good contact with the cone of the valve seat, and it is not well grinded;
⑤ The damping hole of the main valve core is too large and does not play a damping role;
The pilot valve adjusting spring bending, resulting in poor contact between the spool and the cone seat, uneven wear.
The solution:
① Clean the oil tank and pipeline regularly, and filter the hydraulic oil entering the oil tank and pipeline system;
(2) If there is a filter in the pipeline, the secondary filter element should be added, or the filtration accuracy of the secondary component should be replaced; Disassemble and clean the valve components and replace the clean hydraulic oil;
③ Repair or replace unqualified parts;
④ Reduce the damping aperture appropriately.

g, rubber ring wear and not timely replacement.