Discussion on the fault causes of crawler crane ru

2022-10-04
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Talking about the fault causes of crawler crane running deviation

running deviation is a common fault of crawler crane. There are many reasons for running deviation, especially in the construction site, because of the lack of measuring instruments and test devices, it is difficult to analyze. The reasons and judgment methods of crawler crane deviation are introduced with examples below

the fault phenomenon of a crawler crane is that it deviates to the right when moving forward, does not deviate when moving backward, and deviates seriously when the accelerator is high

the walking system of crawler crane is mainly composed of mechanical parts (including driving wheel, guide wheel, carrier roller, roller, crawler) and hydraulic driving parts. During maintenance, the mechanical part should be analyzed first based on the principle of "easy before difficult"

the mechanical part mainly checks two aspects: one is whether the two tracks are parallel; The second is whether the center lines of the drive wheel, guide wheel, carrier sprocket and supporting roller coincide. If either of the two has problems, it will cause walking deviation, but the phenomenon should be that both forward and backward deviate, and the car only deviates when moving forward, so it can be determined that the fault is not caused by the mechanical part. At this time, the hydraulic part needs to be analyzed

when the joystick 5 is pushed, the joystick supplies pressure oil to the brake 1 and opens the brake. At the same time, the joystick supplies pressure oil to the main valve 4 and pushes the main valve spool to act. The main valve supplies pressure oil to the motor 2 and the motor operates, so as to drive the travel reducer to operate and realize the travel of the crawler crane. The brake valve plays the role of parking hydraulic braking, downhill speed limit, etc. From the perspective of the whole walking hydraulic system, any failure of the motor, brake valve, main valve, joystick and other components will cause walking deviation. According to experience, the order of failure rate from high to low is motor, joystick, main valve and brake valve, which are analyzed in turn below

Fuji economy has conducted a market survey on the world's carbon fiber composites and related products. The motor failure is mainly manifested in large internal leakage. If the internal leakage of the right madar is large and the volumetric efficiency is reduced, the speed of the right motor will be lower than that of the left motor, which will cause the forward and backward to deviate to the right. Therefore, it can be determined that it is not the motor failure. In order to confirm this judgment, open the oil drain port of the right motor and conduct the walking test. It is found that the hydraulic oil slowly overflows from the oil drain port, which proves that the internal leakage is normal, and it can be confirmed that the motor has no fault

the common fault of the joystick is that the internal leakage of the valve is large, and the pilot pressure supplied to the main valve is low, causing the main valve to not be fully opened, and the flow of hydraulic oil delivered to the motor is small, resulting in deviation. Forward and backward are controlled by two independent valve cores in the joystick, and the two oil outlets controlling forward and backward of the joystick are exchanged. If there is a phenomenon of backward deviation and no deviation when moving forward, it is reported that the global engineering plastic market is booming, it proves that the joystick is faulty. In the test after replacement, it was found that it was still running to the right when moving forward and not running to the right when moving backward, indicating that it was not the problem of the joystick

the common fault of the main valve is that the leakage in the valve is large, resulting in large flow loss; Or the hydraulic system is not clean, causing the valve core to be stuck, the valve port is not fully opened, and the procedures for correctly operating the cement pressure testing machine have small flow. Because both forward and backward are completed by the same valve core in the main valve, if the leakage in the valve is large, both forward and backward should be deviated, so it can be judged that the possibility of failure with large leakage in the main valve is very small. In order to analyze whether the valve core of the main valve is stuck, replace the pipeline, connect the oil outlet of the main valve controlling the left motor to the right motor, and connect the oil outlet of the main valve controlling the right motor to the left motor. If there is a problem with the main valve, the deviation direction will change, and the fault phenomenon will not change after the walking test, which can prove that there is no problem with the main valve

common faults of the brake valve are large leakage in the valve or inadequate action of the valve core. If there is a large amount of leakage in the valve, both forward and backward should deviate, and it is judged that the failure possibility of a large amount of leakage in the valve is very small. If the valve core is stuck by sundries or the throttle port in the valve is blocked, resulting in the valve core action is not in place, the valve port opening is small, and the hydraulic oil throughput is small, resulting in deviation. When the throttle is high, the experimental force and flow loss of a series of characteristics of the material under tensile load are large, and the deviation will be serious

for this reason, connect a manometer to the oil inlet (P port) of the left and right main valves respectively for the walking test, and it is found that the left and right pressures are basically the same when retreating. However, if the accelerator is small when moving forward, there is little difference between the left and right pressures; If the accelerator is large, the pressure on the right is several megapascals higher than that on the left, which indicates that the valve element of the brake valve controlling the forward direction is not in place and the oil is not flowing smoothly. When the throttle is small, the hydraulic oil flow is small, and the loss of pressure and flow is small. When the throttle is large, the loss of pressure and flow is large, so it causes the fault phenomenon of right deviation when moving forward, no deviation when moving backward, and serious deviation when the throttle is large

disassemble and inspect the brake valve. It is found that the throttle port controlling the forward direction is blocked by sundries, and the fault disappears immediately after cleaning

from the above analysis, it can be seen that there are many reasons for the walking deviation fault of crawler crane. Various possible factors can be considered comprehensively, and then analyzed and judged item by item, confirmed through measurement and test, and eliminated item by item to find the real reason

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