Troubleshooting of the failure of the paver in the

2022-07-29
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Mechanical maintenance: Troubleshooting of paver failure

a TITAN423 paver produced by Shaanxi Construction in 2000 needs to be more cautious about overseas investment in injection molding machines and modified plastics in the future after starting up and witnessing the signing machine of a number of cooperation documents between the two countries and putting the accelerator at the rated speed, the toggle switch S6 at the working gear and the steering gear in the middle When the speed potentiometer is selected at 2m/min and the travel control lever is in the forward position, the following faults occur: when the emergency stop button is pressed and released (the above steps are called initial operation), the left track of the paver does not move, the right track moves forward rapidly, and the machine turns sharply to the left

the walking system of the paver is mainly composed of a walking computer, two walking pumps, two walking motors, a crawler walking mechanism and a speed sensor. The walking computer keeps the walking speed of the 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 that has no bright spot in the transfer case and acts as a brake in the marketing 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, opens the brake, and the brake of the machine is released. The following phenomena occur: the left track does not move, the right track moves forward quickly, and the machine turns sharply to the left. This phenomenon indicates that the fault is not caused by the braking system

(2) apply emergency measures. Turn the emergency change-over switch S70 behind the power distribution box of the main control console to the upward position, so that the machine is in the initial operation state. As a result, the following phenomena occur: the left track moves forward slowly, and the right track moves forward rapidly, resulting in a sharp turn to the left, and the fault is not removed. This indicates that the fault is not caused by the walking computer

(3) replace the plug of the solenoid valve coil of the left and right travel pumps to make the machine 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

(4) unplug the solenoid valve coil plug of the right travel pump to make the machine 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 upward position and make the machine in the initial operation state. As a result, the left track moves forward slowly and the right track moves forward rapidly, causing the machine to turn sharply to the left

(5) unplug the solenoid valve coil plug of the left travel pump with tensile strength>100mpa, so that the machine is in the initial operation state. As a result, the left crawler does not move, and the right crawler moves forward rapidly, resulting in the machine turning sharply to the left; Turn the switch S70 to the upward 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, causing the machine to turn sharply to the left

the above situation shows that the machine fault may be caused by the right travel pump, that is, the right travel pump always outputs large flow in one direction (forward direction)

when the switch S70 is in the normal position (i.e. pulled 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 of the travel computer, but the right travel pump has been outputting large flow in one direction, so the machine turns sharply to the left; When the emergency measures are taken (switch S70 is turned to the up position) and the machine is in the initial operation state, since the left and right travel pumps are not controlled by the travel computer, the left travel pump has a small flow output, which makes the left crawler move forward slowly. However, the single direction large flow output of the right travel pump also causes the machine to turn to the left

(6) in order to further verify the correctness of fault judgment, we performed the following operations:

when the emergency transfer 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 knob switch S6 to the working gear position, center the steering potentiometer, set the speed potentiometer to 2m/min, and push the travel control lever to the reverse position, Press the release emergency stop button. At this time, the left track does not move, the right track moves forward quickly, and the machine turns sharply to the left; Use the emergency measures (switch S70 is turned to the up position) and perform the above backward operation. At this time, the left track slowly retreats, the right track quickly moves forward, and the machine turns sharply to the left

this verification further indicates that the swashplate of the right travel pump is always at the output position of large flow in one direction (forward direction)

the possible cause that the swashplate of the right travel pump is always at the one-way high flow output position is that there is a problem with the solenoid valve (if it is not the problem with the valve, the whole right travel pump can only be removed to the test bench for inspection). Therefore, we removed the solenoid valve of the right travel pump, cleaned it and reassembled it. The fault was eliminated during commissioning

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