Troubleshooting Of Crawler Crane

- Dec 26, 2017-

Crawler crane walking walking the cause of the problem analysis of running deviation is a common fault of crawler crane, the cause of walking wandering many walking crawler crane, especially at the site, due to lack of measuring instrument and test device, analysis more difficult. This paper introduces the reasons and the method of the deviation of crawler crane.

The fault phenomenon of a crawler crane is to move to the right when moving forward, not to run off when backward, and to be serious when the throttle is high.

The walking system of crawler crane consists mainly of mechanical part (including driving wheel, guide wheel, supporting wheel, supporting wheel, track) and hydraulic drive part. In maintenance, the mechanical part should be analyzed first in the principle of first easy to be difficult.

The mechanical part mainly examines two aspects, one is whether the two tracks are parallel; The center line of driving wheel, guide wheel, supporting wheel and supporting wheel is in line. Any one party has a problem, the two will cause walking wandering, but running deviation phenomenon should be forward and backward, and the car just forward running deviation, it can determine the fault is not caused by mechanical parts. The hydraulic part should be analyzed at this time.

At 5 when push the control handle, the control handle to provide pressure oil to brake 1, open the brake, at the same time, the control handle to provide pressure oil to the main valve 4, promote the main valve valve core movement, the main valve to provide pressure oil to the motor 2, the motor running, walking and thus drive reducer, realizes the crawler crane. The brake valve ACTS as the stop hydraulic brake and the downhill speed limit. From the entire walking hydraulic system, any of the motors, the brake valve, the main valve and the control handle can cause the failure of any one of the components. According to the experience, the failure rate is the motor, the control handle, the main valve and the brake valve in the order of high to low.

Motor fault mainly for the discharge of large, if it is on the right side of the motor in the discharge of large, volumetric efficiency is reduced, will cause the right side of the motor rotation speed is lower than the left side of the motor, and this kind of situation will cause forward back all right running deviation, thus can judge is not the fault motor. To confirm this decision, open the drain opening of the right motor and do the walking test, and find that the hydraulic oil is slowly overflowing from the drain, and the internal leakage is proved to be normal, but the motor has no failure.

The common failure of the control handle is the internal discharge volume of the valve. The pilot pressure provided to the main valve is low, so that the main valve is not fully opened, and the hydraulic fluid flow to the motor is small and causes the running deviation. Forward and backward by the control handle in two separate control valve core, the control lever control forward, backward of two oil outlet switch, if appear when running deviation, forward backward without the phenomenon of running deviation, control handle is proved that there are faults. After transposition experiment, it is found that it is still moving forward to the right, backward without deviation, indicating that it is not the control handle.

The common failure of main valve is large leakage in the valve, resulting in large flow loss; Or the hydraulic system is not clean, causing the valve core lag, the valve opening is not complete, the flow is small. As both advance and back are completed by the same valve core in the main valve, if the leakage in the valve is large, the forward and backward should be biased, so it is very unlikely that the leakage in the main valve can be found. Whether binding for the analysis of the main valve valve core, a change of line, will control the main valve oil outlet left motor received right motor, motor control right of the main valve oil outlet received left motor, if the main valve has a problem, running deviation direction will change, to walk after test failure phenomenon did not change, to prove that the main valve is no problem.

The common failure of the brake valve is large leakage in the valve or not in the valve core movement. If the leakage in the valve is large, the forward and backward should run off, and the probability of failure is very small. If the valve core is sundry binding or throttling mouth blockage in the valve action does not reach the designated position, lead to valve core valve opening a small mouth, small amount of hydraulic oil through and running deviation, caused by pressure and flow down when the loss is big, running deviation will be serious.

For this reason, the inlet port (P port) of the main valve of the left and right main valve is used to carry out the walking test, and it is found that the left and right pressure are basically the same. But if the accelerator is moving forward, the pressure on the left and right side is different. If the accelerator is on the right side, the pressure on the right side is a few gigabytes higher than the left side, indicating that the control movement of the brake valve is not in place and the oil is not smooth. Small throttle hydraulic oil flow rate, pressure and flow loss is small, large gas pressure and flow of the loss is bigger, so cause forward to run right slant, back when not running deviation, and down when the wandering serious fault phenomenon.

Check the brake valve and find that the choke hole that controls the forward direction is blocked by debris, and the failure of cleaning after cleaning is disappeared.

Analysis by above knowable, after walking for a crawler crane running deviation fault, for many reasons, can fully consider all possible factors, and then determine the item by item analysis, and identified by measurement and test, item by item, ruled out, in order to find the real reason.

Elephant Group 

Add:InTime Center,No.1600, Kejiguan Road,Binjiang District,Hangzhou, Zhejiang province, China.