Control function of Hitachi excavator hydraulic pump controller. According to the stroke of the joystick, the displacement of the pressure pump is controlled to reduce the median loss and fine control loss. The stick half-flow mode set by .I for the white motion provides a fine control function. The cut-off function and cut-off function cancellation together with the 2-level overflow function provide a guarantee for reducing the overflow loss and increasing the digging power.
1. Flow control function
When the control lever is in the neutral position, the electric signal is sent to the hydraulic pump excavator through the hydraulic switch of the pilot control valve.After processing by the microcomputer in the controller, the driving signal is sent to the hydraulic pump system to make the hydraulic pump catch. The quantity is controlled to the minimum, reducing the power loss when the control valve is in the neutral position. When the joystick is pulled, the oil pressure switch delivers the electrical signal of the corresponding flow command to the hydraulic pump controller according to the stroke of the joystick. The microcomputer in the controller processes the corresponding drive signal and sends it to the hydraulic pump system to obtain the corresponding response from the surface. The performance of fine excavation of hydraulic pump displacement is improved and power loss is reduced.
2. Cut-off (C0) function
When the load increases during operation, the outlet pressure of the hydraulic pump rises.When the pressure is close to the overflow pressure, the oil pressure sensor at the outlet sends a corresponding electrical signal to the controller and the microcomputer processes the corresponding drive signal to the hydraulic pump system. The cut-off (CO) valve performs the cut-off function, which reduces the displacement of the hydraulic pump and reduces the overflow loss.
3. Cut-off (CO) cancellation function
The opening or canceling of the cut-off function is automatically determined by the three switches or one of the maximum power switch, walking joystick and swing lock switch.When the maximum power switch is in the on position (the working mode switch must be in (HO) or GO), when the walking operation lever is in the operating position and the four-turn lock switch is in the on position, their signal current is sent to the hydraulic pump controller.After being buried at the machine, the corresponding driving signal is sent to the hydraulic pump system to make Cut-off (CO) cancellation The solenoid valve cut-off function is cancelled. When the load increases during operation, the outlet pressure of the hydraulic pump increases and approaches the overflow pressure, and the discharge of the hydraulic pump will not decrease. This can not only ensure the flow rate, but also prevent the speed drop.
4. Stick half flow control function
When the working mode switch is in (FO or (L0), the electric signal of the working mode switch of the monitor panel is sent to the hydraulic pump controller, and after processing by the microcomputer, the corresponding driving signal is sent to the half-flow solenoid valve of the stick to make the main operation The operation of the "stick-high-speed" operation valve of the quadruple directional valve in the valve is stopped, and the stick cylinder is only supplied with a single pump at this time, which improves the precision of fine control and finishing operations. This action is limited to the simultaneous action of the boom and the stick, and when the stick is extended and the bucket is operated at the same time, the half-flow control function does not work.
5.2-level overflow control function
When the maximum power switch is pushed to the open position (only when the working mode switch is in (HO) or [GO), or the walking joystick is in the operating position, or the rotary lock switch is in the open position, their electrical signals are sent to the hydraulic pump for control After processing by the microcomputer, the drive signal is input to the 2-stage overflow.C0 cancels the solenoid valve.At this time, the solenoid valve is opened, the cut-off function is canceled, and the pilot pressure oil from the pilot pump flows into the main relief valve. The pressure is increased from 32.5MPa to 34MPa, increasing the digging power and walking force.
6. TVC standby switch is the control function when it is turned on
If the controller or sensor is abnormal, DC power flows from the beryllium battery to the torsion control valve. At this time, the displacement of the hydraulic pump is controlled according to the pressure of the hydraulic pump outlet. This function can be used to control the driving torque of the hydraulic pump.
7. Swing lock and spin brake control function
When the rotary lock switch is in the OHF position, the rotary brake acts after the rotary joystick is placed in the neutral position.The rotary brake is released when the rotary joystick is operated, and the turntable can freely rotate when the rotary lock switch is ON When in position, the turntable is braked by the swing brake. Even if the joystick is operated, the swing brake will not be eliminated, so the turntable cannot turn, preventing hydraulic drift after stopping the swing.
When the hydraulic pump controller is abnormal and the rotary brake function is abnormal, the rotary lock standby switch cancels the rotary brake well to perform the rotary operation. Rotary lock standby switch Rotary lock switch and rotary brake operation table as shown in Table 2-5
When the rotary lock switch is turned to the ON position, the cut-off (CO) function is cancelled. In this case, if the hydraulic system of the working device is in an overflow state, the temperature of the hydraulic oil rises rapidly to reduce the warm-up time.
