The composition of Doosan excavator final drive
The final drive consists of a hydraulic motor, a genuine gearbox, a brake valve, a parking brake, etc.
1) The role of the hydraulic motor The hydraulic motor is a swash plate type axial piston motor, which converts the hydraulic pressure of the hydraulic oil from the main pump into the rotational torque of the rotary motion
2) The role of the brake valve (the brake includes a safety suction valve and a balance valve) when the main valve spool returns to the neutral position, the walking motor continues to rotate due to the inertia of the car body, and the motor acts as a pump to make the return The high pressure back pressure on the oil side forces the motor to stop and brakes.
3) The function of the parking brake The parking brake is a friction disc brake mechanism, which is integrated with the hydraulic motor.
When the excavator is parked on the sloping ground, avoid the phenomenon of rolling and slipping.
(3) Three working processes of final drive
work process 1
1) Release the brake:
Operate the walking joystick
The hydraulic oil from the control valve enters the balance valve (19) through the small hole on the balance valve (19). The balance valve (19) moves upward and the pressure oil enters the cavity A of the brake piston (12) in the direction of the arrow. The spring (11) pair The force of the friction plate is eliminated and the brake is released
(4) Speed conversion of traveling motor
When the flow rate of the pump is constant, the speed of the motor rotation can be changed by changing the angle of the motor swash plate (4) ① When the walking speed is selected at low speed (L), the solenoid valve is not energized. The pilot oil from the pilot pump cannot flow to the throttle. The end face of the device reading (9). The travel motor swash plate (4) angle is at the maximum position. The travel motor has a large capacity and low speed. When the travel speed is selected at high speed, the electromagnetic read energizes, the angle of the swash plate becomes smaller, and the travel motor capacity becomes smaller and the speed becomes faster.
