How to solve the problem that paver can't walk

Paver is one of the most important machines in pavement construction. How to remove the faults in application quickly should be considered from three aspects: mechanical system, hydraulic system and electrical system.

For example, when starting the engine and setting the throttle at the rated speed, turning the button switch S6 to the working position, turning the potentiometer in the middle, selecting the speed potentiometer at 2m / min, and driving the control lever in the forward position, the following faults occur: when pressing the release emergency stop button (the above several) Step operation is called initial operation). The paver will not move the left track, the right track will move forward rapidly, and the machine will turn sharply to the left.

The traveling system of paver is mainly composed of traveling computer, two traveling pumps, two traveling motors, crawler traveling mechanism and speed sensor. Among them, the traveling computer keeps the traveling speed of paver constant, so as to meet the construction requirements. In order to find out the cause of the fault, we carry out the following fault diagnosis according to the structure and working principle of the walking system.

(1) Release the brake. First, push the black knob of the two position four-way valve on the transfer case and turn it clockwise to make the paver in the initial operation state. At this time, the pressure oil of the right travel pump reaches the brake cylinder and the brake is opened. The brake of the machine is released. The following phenomena occur: the left track is not moving, the right track is moving forward rapidly, and the machine is turning sharply to the left. This phenomenon indicates that the fault is not caused by the brake system.

(2) Use emergency measures. Turn the emergency change-over switch S70 behind the power distribution box of the main control console to the up position, so that the machine is in the initial operation state, and the following phenomena occur as a result: the left track is slowly moving forward, and the right track is fast moving forward, resulting in a sharp turn to the left, and the fault has not been removed. This shows that the fault is not caused by the walking computer.

(3) Change the plug of solenoid valve coil of left and right propel pump to make the machine in initial operation state. At this time, the left track does not move, and the right track moves forward rapidly, causing the machine to turn sharply to the left.

(4) Unplug the coil plug of the solenoid valve of the right propel pump, so that the machine is in the initial operation state. At this time, the left track does not move and the right track moves forward rapidly, causing the machine to turn sharply to the left; turn the switch S70 to the up position and make the machine in the initial operation state, resulting in the left track moving slowly and the right track moving rapidly, causing the machine to turn sharply to the left.

(5) Pull off the plug of the solenoid valve coil of the left travel pump to make the machine in the initial operation state. As a result, the left track does not move and the right track moves forward rapidly, resulting in a sharp turn of the machine to the left. Turn the switch S70 to the up position and make the machine in the initial operation state. At this time, the left track does not move and the right track moves forward rapidly, resulting in a sharp turn of the machine to the left.

The above situation shows that the failure of the machine may be caused by the right propel pump, that is, the right propel pump has been outputting large flow in one direction (forward direction).

When the switch S70 is in the normal position (i.e. to the down position) and the machine is in the initial operation state, the left travel pump has no flow output due to the protection function of the travel computer, but the right travel pump has been in the output of large flow in one direction, so that the machine turns sharply to the left; when emergency measures (switch S70 to the up position) are used and the machine is in the initial operation state In the state, since both the left and right propelling pumps are not controlled by the propelling computer, the left propelling pump has a small flow output, which makes the left track move forward slowly. However, due to the output of large flow in one direction of the right propelling pump, the machine also turns to the left.

(6) In order to further verify the correctness of fault judgment, we have carried out the following operations:

When the emergency change-over switch is placed in the normal position (switch S70 is turned to the down position), start the engine and adjust the throttle to the rated speed, turn the button switch S6 to the working position, the steering potentiometer is in the middle, the speed potentiometer is set at 2m / min, the travel control lever is pushed to the backward position, and the release emergency stop button is pressed. At this time, the left track fails to move and the right track appears The side track moves forward rapidly, and the machine turns sharply to the left; use emergency measures (switch S70 to the up position), and perform the above backward operation. At this time, the left track moves backward slowly, the right track moves forward rapidly, and the machine turns sharply to the left.

The verification further shows that the swashplate of the right propel pump is always at the output position of large flow in one direction (forward direction).

The possible reason that the swashplate of the right propel pump has been in the single direction large flow output position is that there is a problem with the solenoid valve (if it is not a problem with the valve, only the whole right propel pump is removed to the test bench for inspection). Therefore, we remove the solenoid valve of the right travel pump, install it after cleaning, and the fault has been eliminated during the test.