Travel three-speed control and maximum flow cut-off control principle, travel timing diagram (S, H mode).
1. When S mode is selected
(1) When the travel pressure switch and the upper pressure switch are in the 0N position, the controller will not output a control signal to the travel switching solenoid valve. At this time, the displacement of the main pump is the standard (mid-range) displacement, and the travel motor swash plate is at a low level. Displacement location.
(2) High-speed running state (press the switch again when in the middle-speed walking state, you can switch to the high-speed walking state). The travel switching solenoid valve is at the 0N position, while the travel motor swash plate is at the high displacement position.
(3) Low-speed running state (press the switch again when in high-speed walking state to switch to low-speed walking state).
Once the walking switch is switched, the maximum flow cut-off solenoid valve is turned ON to realize the maximum flow cut-off control. The swash plate of the travel motor is in the low displacement position, at which time the main pump realizes the maximum flow cut-off control.
When the upper pressure switch is in the ON position, the maximum flow cutoff solenoid valve is not turned on (OFF), so the maximum flow cutoff control cannot be achieved.
2. When H mode is selected
(1) When running at medium speed, the swash plate of the travel motor is in the low displacement position, and the output flow of the main pump is the standard (mid-range) flow.
(2) When running at high speed, the swash plate of the travel motor is at the high displacement position.
(3) When running at low speed, the main pump output maximum flow cutoff control is achieved, the same as in the s mode.
3. When L, F mode is selected
Walking timing chart (L, F mode).
(1) When running at medium speed, the swash plate of the travel motor is in the low displacement position, and the output flow of the main pump is the standard (mid-range) flow.
(2) When running at high speed, the swash plate of the travel motor is at the high displacement position.
(3) When running at low speed, the main pump output maximum flow cutoff control is realized.
4. When F mode is selected
When F mode is selected, the signal of the upper pressure switch can be used to achieve the maximum flow cutoff control of the main pump output.
(1) When the excavator is running at medium speed, the walking handle is operated separately, the swash plate of the walking motor is in the low displacement position, and the output flow of the main pump is the standard (mid-range) flow; when the upper working device is operated alone, the maximum flow of the main pump output is achieved Cut-off control; while the excavator is walking, the upper working device also moves, and the swash plate of the walking motor is in the low-displacement position to realize the cut-off control of the maximum flow rate of the main pump output.
(2) When the excavator is running at high speed, the walking handle is operated separately, the swash plate of the walking motor is in the low displacement position, and the output flow of the main pump is the standard (mid-range) flow; when the upper working device is operated alone, the maximum flow output of the main pump is cut off Control: While the excavator is walking, the upper working device also operates to achieve the maximum flow cut-off control of the main pump output.
(3) When the excavator is running at low speed, the walking joystick is operated separately, and the swash plate of the walking motor is at the low displacement position to realize the maximum flow cutoff control of the main pump output. When the upper working device is operated independently, the main pump output maximum flow cutoff control is realized.
While the excavator is moving, the upper working device is also operating, the swash plate of the walking motor is in the low displacement position, and the output flow of the main pump is the standard (mid-range) flow.
The relationship between the traveling speed of the excavator, the displacement of the traveling motor, and the output flow of the main pump is shown in Table 12-5.
The walking speed and power mode are independent of each other. The walking speed varies with the walking mode and the power mode.
