How to solve the aging problem and maintenance of aging equipment

After a period of use, loaders, excavators and other machines often suffer from poor sensitivity of the control mechanism, slow movement of the working mechanism and so on.

1, phenomenon

Engine exhaust, running, sound all abnormal, difficult to start, slow down;

The oil in the hydraulic system is polluted, the hydraulic components and pipelines, the external and internal oil discharge of the joint are serious, and the hydraulic cylinder can not be locked and retracted automatically;

The driving handle of the whole machine is loose in chain and difficult to handle when operated.

2, reasons

Mainly for long hours of overload work, and in the environment does not meet the requirements of the job;

Daily maintenance is not timely, large, medium and small not up to standard requirements.

3, measures

(1) strictly manage and constantly improve the technical quality of operators, and ensure the correct use of construction machinery.

(2) strengthen the routine maintenance and inspection of equipment, and improve the rate of equipment readiness.

(3) to improve the maintenance personnel technical level and sense of responsibility, to ensure the quality of large, medium and small. Proper increase of special maintenance equipment, tools, instruments and technical data.

(4) adjust and repair the machinery

4, adjustment and repair methods

(1) adjustment of engine throttle;

For example, a diesel engine fitted with an automobile crane, after a long period of use, sometimes grows slowly and fails to reach the maximum speed and maximum power when it is operated on the car. At this point, you need to check and adjust the entire transmission chain on the pedal accelerator.

The job requires two people, one in the car to control the accelerator pedal, and the other to observe the movement of the governor lever at the injection pump. For many years, the operator in the cab has stepped the accelerator pedal to the limit position, but in fact, the speed regulating lever of the diesel injection pump can not reach the limit position sometimes.

Because the speed control rod in the whole machine in the position of the operator is not easy to observe the location, its empty stroke is often ignored, so should observe more a while, try several times.

The reason for this is the change in the dimension chain of the transmission system of the diesel engine's throttle, in which the gap between the lines is accumulated too much. Two, some fasteners on the transmission, such as the fastening screws, are loose.

At this point should be checked according to the size of the accelerator chain, when the car pedal in the end, the governor must also reach the limit. The empty course of the throttle drive chain shall be taken as required, and shall be tightened and adjusted according to the specific conditions of each device.

(2) repair of gear pump;

Gear pump wear, mainly pump shell internal surface, tooth top and tooth thickness wear. The repair method is: in the pump shell surface wear brush plating coating a layer of metal, to restore the original size; on the gear tooth top and tooth thickness of plating, restoration of tooth thickness and tooth top size; sleeve is generally not only for repair, replacement and sleeve must pay attention to the axial length, do not leave space. The same type of gear pump can be used for accurate measurement, and then choose to wear more light gear and pump body for re assembly, loading and testing on the test bench.

(3) repair of plunger pump;

Piston pump wear is mainly the plunger surface and rotor and piston matching hole.

Repair methods: according to the measured wear of plunger hole size reconstituting plunger, plunger new material, heat treatment process and the diameter size and surface roughness are in accordance with the relevant technical requirements; before the assembly, for with a new piston hole grinding.

In addition, can also be used in some of the same model used in piston pump wear lighter plunger and the plunger hole re combination with rotor. In general, the clearance between the old plunger and the hole shall not exceed 35 m, and shall be scrapped when the amount of wear reaches 45 mu m.

(4) control valve repair;

The new valve stem should be prepared according to wear stem hole size as measured by the new valve stem material, heat treatment process, the size and surface roughness to ensure compliance with relevant technical requirements; the assembly will be the best stem hole grinding on the valve stem and the new look, (the most good to car a core technology used for grinding shaft), if the condition does not have also used new stem grinding at the same time, but also on the positioning control valve spring and pressure adjusting device of the return spring for testing, to see whether it meets the requirements.

Can also be based on the degree of wear on each valve hole to determine the method of repair, if there are more than the same type of old valve, can be between several units for testing and deployment.

The repaired valve shall be tested on the test bench, or the valve shall be placed flat. The top two holes shall be filled with kerosene, and the oil leakage rate shall be measured by a stopwatch to determine the sealing degree of the valve.

(5) repair of hydraulic cylinder;

Hydraulic cylinder leakage and leakage reasons: first, piston rod (or plunger) surface wear serious or pull out groove mark, can be plated or metal brush plating method repair. Two is the guide sleeve to the inner surface of the guide sleeve wear, because of low price, are generally replaced. Three is the hydraulic cylinder itself is badly worn or out of the deep groove, or in the cylinder wall cavitation area, this can also be brush plating process for repair. Four is the piston seal rubber ring wear, at this time can change.

Internal and external leakage will cause the hydraulic cylinder to retract automatically, there are 3 kinds of inspection methods for the hydraulic cylinder installed in the car with a dial indicator, the magnetic meter base adsorbed on the piston rod of the hydraulic cylinder, the cylinder end against the on hand in the observation engine (including the following two 15min methods) before and after the change value is hydraulic cylinder shrinkage; two is the piston rod on a piece of paper with butter stick slip to the hydraulic cylinder, measuring the upper end of the distance change, namely hydraulic cylinder retraction; three is a rubber plate with a loosening and lock tight lock on the piston rod and the measurement method and the measurement method for the same disk.

The method mentioned above is also a method to judge whether the hydraulic cylinder leaks or not.

According to the liquid pressure cylinder retraction, can more accurately calculate the piston seal wear degree and equipment usage time, if the use of a very short time, it can be concluded that the seal is damaged due to improper assembly method; it is very useful for correcting errors and assembly method to determine the hydraulic cylinder the degree of relief.

(6) cleaning the hydraulic system and filtering the hydraulic oil

Hydraulic oil pollution is the main factor of engineering machinery failure, accounting for about 80% of the proportion. Therefore, the hydraulic oil must be checked regularly. When conditions are rough, 120 purpose filter screen can be used for filtration;

At the same time, regularly clean the tank and the whole hydraulic system, or change the oil regularly.

(7) adjustment and repair of operation and control device;

The operation and control device includes various handles, buttons, accelerator pedals, etc., and the handles that are easy to be loosened are inspected regularly to see their harmful size, and the locking device is readjusted or tightened;

Badly worn parts can be welded, repaired or replaced;

For the switch or button of an electric type, the contact state or replacement parts of the contact can be adjusted.