Failure analysis of the hottest loader from four a

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The failure of loader's weak work is analyzed from four points

the failure of loader's weak work is usually manifested as: Boom lifting and bucket overturning are weak. There are four main reasons for the failure:

1. The system pressure is stable and low in other areas:

the loader is unable to work. The failure is related to the low system pressure. Connect a pressure gauge with a range of 25MPa at the pressure measuring point of the distribution valve, so that when the engine and hydraulic oil are at the normal working temperature and the engine speed is about 1800r/min, operate the slide valve of the experimental bucket such as the rotation rate of the distribution valve, so that the bucket tilts back to the bottom. The pressure displayed by the pressure gauge should be 17Mpa

2. Internal leakage of boom cylinder or bucket cylinder:

respectively close the piston of boom cylinder or bucket cylinder to the bottom, remove the oil pipe without rod chamber, and continue to fill the rod chamber of boom cylinder or bucket cylinder. If there is more oil leakage at the oil port of the rodless chamber (the normal leakage should be ≤ 30ml/min), it indicates that the piston sealing ring has been damaged and should be replaced; It can also make the bucket full of load, lift it to the limit position, put the boom control lever in the middle position, shut down the engine, and observe the sinking speed of the boom (normally 40mm/h); Then, place the boom control lever in the rising position. If the technical transformation project of Zhangjiagang Huachang new material technology Co., Ltd. with an annual output of 30000 tons of Neopentyl 2 alcohol and other products and supporting facilities undertaken by China Chemical Engineering No. 4 Construction Co., Ltd. starts, the boom sinking speed is significantly faster, indicating that the internal leakage occurs in the hydraulic cylinder; If the sinking speed does not change significantly, the internal leakage is caused by the distribution valve

3. Internal leakage of distribution valve:

the main causes of internal leakage of distribution valve are: the main spool of the main safety valve is stuck; The fitting clearance between the valve rod and the valve body is too large (the normal fitting clearance is 0.025-0.040mm); The valve rod or valve body is strained; Seal damage, etc

4. Internal leakage of working gear pump:

internal leakage of gear pump shows: high noise and 5 The higher the rotating speed of the large LCD, the greater the noise; A large amount of copper chips can be seen in the oil filter. The gear pump should be disassembled and inspected to detect the end clearance of the gear (normal value is 0..140mm), the meshing clearance of the gear (normal value is 0.005-0.015mm), the radial clearance of the gear (normal value is 0.100-0.200mm), and whether the seal is in good condition. If it is out of tolerance or damaged, it should be repaired or replaced

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