Inspection method of Kobelco excavator hydraulic system
1. Pilot control pressure check of main control valve
Install a T-shaped joint between the pilot oil pipe and the main control valve control oil, install a 4900kPa pressure gauge on the T-shaped joint, and operate the corresponding hydraulic pilot control valve handle, then the pressure gauge will show the control port. Pilot pressure.
2. Check the leakage of the rotary motor casing (models with rotary latch)
Check the leakage of the rotary motor housing is to check the performance of the rotary motor, as follows:
(1) Remove the drain pipe from the T-joint of the rotary motor
(2) Install a screw plug (3/4”-16) at the open end of the drain pipe and a nut (3/4”-16) at the opening of the T-shaped joint
(3) Remove the drain pipe from the center rotary joint and install a nut (3/4”-16).
(4) Put one end of the drain pipe into a suitable metering container.
(5) Insert the rotary latch into the locked position and operate the rotary control valve for lmin. (6) Measure the leakage of the rotary motor casing. When the set pressure of the rotary safety valve is (24000±490) kPa, the maximum value of the rotary motor casing leakage is : 201/mi (new motor), 231./min (motor after overhaul).
3. Check the leakage of the rotary motor casing (models without rotary barrel pin)
(1) Stop the engine and release the oil pressure in the hydraulic system
(2) Remove the drain pipe from the T-joint of the rotary motor
(3) Block the open end of the discharge pipe with a screw (3/4″-16), and plug the oil port of the T-shaped joint with a butterfly mother (3/4”-16)
(4) Remove the drain pipe from the central rotary joint and install a nut (3/4”-16).
(5) Put one end of the drain pipe into a suitable metering container.
(6) Remove the brake and release the pilot oil pipe, so that the interrogation brake is in the braking position.
(7) Start the engine, the power mode selection switch is in position Ⅲ, the engine throttle knob is in position 10. The engine runs at high speed without load, and the engine speed is (1860±50) r/min
(8) Let the hydraulic oil temperature reach (55±5)℃.
(9) Operate the rotary control valve for 1min to measure the leakage of the rotary Naida casing
10) Stop the engine, release the oil in the hydraulic system, release the swing parking brake to restart the engine, operate the swing control valve, and turn the swing motor to a new position.
Repeat the above steps and measure 3 times
When the set pressure of the rotary safety valve is (24000±490) kPa, the maximum leakage of the rotary motor housing is (new motor), 23L/min (motor after overhaul).
1. Leakage inspection of walking motor housing
(1) Remove the drain pipe of Naida, and plug the-end of the drain pipe with a screw plug.
(2) Connect a plastic hose to the oil drain, put the other end of the plastic hose into a suitable metering container
(3) Clamp the track with a track pin to prevent rotation and operate the travel control valve for 1min
(4) Measure the leakage of the travel motor housing.
(5) Remove the track latch and start the excavator walking motor to another position.
(6) Repeat the above steps.
When the set pressure of the travel safety valve is (34300±490)kPa, the maximum leakage of the travel motor housing is: 15Lmin (new motor), 18L/min (motor after overhaul).
2. Main pump exhaust
When the excavator repairs the main pump or after replacing the hydraulic oil, the air in the hydraulic system must be exhausted. The exhaust steps are as follows:
(1) Stop the engine, remove the bleed plug from the top of the main pump, wait a few minutes until the main pump is filled with hydraulic oil, and then install the bleed plug. Start the engine at a low speed and raise the starting arm to maintain the raised position of the boom.
(2) Turn off the engine and slowly lower the boom until the bucket falls to the ground. This will pressurize the hydraulic tank.
(3) Slowly loosen the bleed screw to exhaust the air until the hydraulic oil flows out, which indicates that the air in the main pump has been exhausted
(4) Tighten the bleed screw.
3. Relief of hydraulic system pressure
Before the hydraulic oil pipes or components are disconnected or disassembled, the pressure of the hydraulic system must be released. The method of releasing is as follows:
(1) Retract all the piston rods of the stick cylinder.
(2) Adjust the position of the bucket so that the bucket is placed flat on the ground when the movers descend.
(3) Lower the boom until the bucket is flat on the ground
(4) Turn off the engine, operate the joystick of the hydraulic control valve back and forth to release the pressure existing in the pilot system.
(5) Slowly loosen the bleed screw on the hydraulic tank to release the pressure.
(6) Tighten the bleed butterfly plug on the hydraulic oil tank.
(7) After the pressure of the hydraulic system is released, the hydraulic tubing and components can be removed.
