Komatsu PC220-8M0 excavator final drive principle

The final drive consists of a travel motor and a speed reduction mechanism. There are two left and right final drives on the excavator. Direct drive of the track enables the excavator to advance, retreat and turn.

Komatsu PC220-8M0 excavator final drive working process

    1 speed reduction mechanism

    The final drive speed reduction mechanism is mainly decelerated by the secondary planetary gears.

    2 travel motor

    The traveling motor is a swash plate type axial piston motor, and the pressure of the pressure oil transmitted from the main pump is converted into the driving force of the turning motion. When the traveling motor is stopped, the traveling motor continues to rotate due to the inertia of the body. The dynamic valve (including the safety suction valve and the balancing valve) acts to stop it. In order to prevent the excavator from stopping on the inclined ground, the parking brake is provided. The brake is integrated with the hydraulic motor.

Komatsu PC220-8M0 excavator final drive principle

    . Release the brake

    When the walking lever is operated, the hydraulic oil from the control valve enters the balancing valve through the small hole in the balancing valve 19, so that the balancing valve moves upward, the pressure oil enters the cavity A of the brake piston 12 in the direction of the arrow, and the spring 11 cancels the friction plate 13 And the force of the pressure plate 14, the brake is released.

    When walking

    The pressure oil from the control valve is sent to the port PA, the pressure oil flows to the chamber SI through the orifices El, E2 in the balancing valve 19, the balancing valve 19 moves to the right in the direction of the arrow, and the pressure oil of the port PA Push open the safety suction valve 18A. It flows into the final drive motor port MA and flows out from the port MB. The drive motor rotates, and the pressure oil flowing out from the port MB flows back to the port PB in the direction of the arrow.

    Stop walking

    When the travel lever returns to the neutral position, the motor inlet port PA is cut off, the pressure in the S1 chamber drops, the balance valve returns to the neutral position, the oil passage of the oil outlet passage B1 is cut, and the friction plate 13 and the pressure plate 14 are spring-loaded. Ll pushed together to produce a brake.

    . Motor speed adjustment

    When the flow rate of the pump is constant, the motor speed can be changed by changing the angle of the motor swash plate 4.

Select the running medium speed (Mi) or low end face on the monitoring panel, push the spool of the regulator valve 9 to the left, and the main pressure oil from the control valve enters the bottom regulator through the oil passage d in the regulator valve 9. The piston 15 pushes the regulator piston to the right, the angle of the swash plate becomes smaller, the capacity of the traveling motor becomes smaller, and the rotation speed becomes faster.

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