Actuator Control System

1) Walking automatic two-speed system The walking automatic two-speed system has this function only when the walking speed switch is in the second-speed position. At this time, its signal makes the traveling second-speed solenoid valve reverse direction; at the same time, the traveling motor is placed at the second-speed position through the second-speed servo cylinder, and the excavator can travel at high speed.

In addition, the control selector valve is also affected by the travel pressure. When the load is heavy such as uphill, the control selector valve is reversed to the side of the first speed; the second speed is unloaded by the servo control oil pressure, so that the travel motor automatically moves to the first speed. The speed position is changed, and the driving force is increased.

When the excavator is walking on flat ground or walking downhill, the walking resistance becomes smaller, the control selector valve is reversed again, and the servo cylinder is used for the second speed, and the travel motor automatically returns to the second speed position, so that the control machine Walk at high speed.

2) Rotary shake prevention mechanism of the turntable The rotational shake prevention mechanism of the turntable is a mechanism that eliminates the shaking of the excavator turntable after the rotation stops. Its working principle is:

In the process of turning the horse over and stopping, the reverse rotation prevents the two sides of the valve from being affected by the unloading pressure sensor, and the spring is compressed. Since the left and right pressures are equal, the reverse rotation prevention valve cannot be reversed.

After the rotary motor stops, the pressure on the B port side is higher than that on the A port side, which produces a reaction force on the rotary motor, and the rotary motor shakes. At this time, the pressure on the A port side is higher than that on the B port side, which generates pressure on the reverse rotation prevention valve. Due to the orifice in the valve, the time lag occurs, and the spool valve moves to the right, so that the A port and the B port are connected and the pressure is equal. Therefore, the rotary shake of the turntable is only one time.

3) Working device control system There are six actuators in the hydraulic system of the hydraulic excavator - the left and right travel motors, the rotary motor of the relay table, the boom hydraulic cylinder, the stick hydraulic cylinder, and the bucket hydraulic cylinder. In order to improve the productivity of the excavator and save energy consumption, during the excavation and loading process of the excavator, the coordinated action of the rotary motor and the three hydraulic cylinders is required, that is, the working device control system should have the following three functions:

(1) Control machine control function. The bucket moves along the horizontal plane or a straight line at a certain angle with the horizontal plane, circular arc movement; arbitrary trajectory movement.

(2) Load excavation function. Complete bucket lifting, swinging and unloading. In this process, the bucket is required to maintain the angle at the beginning of the lifting relative to the ground plane to prevent the material in the bucket from being scattered during the lifting process.

(3) Reset control function. After unloading, through the linkage of the four movements of boom, stick, bucket and rotation, the bucket is restored to the position where it started to dig.

The control forms of the above-mentioned excavator working devices are organic-liquid control and computer control.