For some second-hand construction machinery and equipment that have been idle for a long time, old construction machinery and equipment. Before use, the equipment must be tested. Today, let's talk about the testing process before use.
engine
Phenomenon: the engine exhaust, operation and sound are all abnormal, it is difficult to start, and the acceleration is slow; The oil in the hydraulic system is polluted, the external and internal oil drainage of hydraulic components, pipelines and joints are serious, and the hydraulic cylinder cannot be locked and retracts automatically; The transmission chain of each control handle of the whole machine is loose, and the operation is blocked and laborious.
Cause: it is mainly caused by long-time overload work and operation in an environment that does not meet the requirements; Daily maintenance is not timely, and major, medium and minor repairs fail to meet the standard requirements.
measures
(1) Strictly manage and continuously improve the technical quality of operators to ensure the correct use of construction machinery. (2) Strengthen the daily maintenance and inspection of equipment to improve the intactness rate of equipment. (3) Improve the technical level and sense of responsibility of maintenance personnel to ensure the quality of major, medium and minor repairs. Appropriate increase of special maintenance equipment, tools, instruments and technical data.
Adjustment and repair of machinery
Adjustment and repair methods
(1) Repair of gear pump
The wear of gear pump mainly refers to the wear of inner surface of pump housing, tooth top and tooth thickness. The repair method is: brush a layer of metal coating solution on the worn part of the inner surface of the pump housing to restore its original size; For gears, the tooth top and tooth thickness can be electroplated to restore the tooth thickness and tooth top dimensions; Generally, the shaft sleeve is only replaced but not repaired. When replacing a new shaft sleeve, attention must be paid to its axial length and no space must be left. Several used gear pumps of the same model can be accurately measured, and then the gears with light wear and pump body can be re assembled and tested on the test bench.
(2) Hydraulic cylinder repair
Causes of internal and external leakage of hydraulic cylinder:
First, the piston rod (or plunger) surface is seriously worn or pulled out of the groove mark, which can be repaired by electroplating or metal brush plating.
Second, the inner surface of the guide sleeve is worn. Because the guide sleeve is cheap, it is usually replaced.
Third, the hydraulic cylinder body itself is seriously worn or pulled out of the deep groove, or there is a cavitation area on the inner wall of the cylinder body, which can also be repaired by brush plating process.
Fourth, the sealing rubber ring on the piston is worn, and it can be replaced at this time.
Both internal leakage and external leakage will make the hydraulic cylinder retract automatically. There are three inspection methods for the hydraulic cylinder installed on the vehicle:
First, use a dial indicator to adsorb the magnetic gauge base on the piston rod of the hydraulic cylinder, with the gauge needle against the end face of the cylinder barrel, and observe the change value of the gauge needle before and after the engine shuts down for 15min (including the following two methods), that is, the retraction amount of the hydraulic cylinder;
Second, stick a piece of paper on the extended piston rod with grease, and measure the change of the distance from the upper end of the paper to the end of the hydraulic cylinder, that is, the retraction of the hydraulic cylinder;
Thirdly, a rubber plate that can be loosened and locked is used to lock the piston rod. The measurement method is the same as that of using paper.
The above detection method is also a method to judge whether the hydraulic cylinder has internal leakage and its degree. According to the measured retraction of the hydraulic cylinder, the wear degree of the seal on the piston and the service time of the equipment can be accurately calculated. If the service time is very short, it can be concluded that the seal is damaged due to improper assembly methods; This is very useful for correcting the wrong assembly method and judging the internal leakage degree of the hydraulic cylinder.
