Hydraulic equipment rapid fault diagnosis method - Database & Sql Blog Articles

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In the maintenance process of hydraulic equipment, some practical diagnostic methods are used to diagnose the failure of hydraulic equipment, which has strong operability. Therefore, it is widely used in maintenance. The following summarizes and introduces several practical troubleshooting methods.
1. Replacement method

The same components on the same type, the same structure, and the same principle of hydraulic equipment are replaced (interchangeable) at the same position to prove whether the replaced components work reliably. For example, the A component is replaced with a B-machine and turned on to observe the quality of the component. The advantage of the replacement method is that even if the repairer's technical level is low, this method can be applied to make an accurate diagnosis of the failure of the hydraulic equipment. However, the application of this method must be based on the same type, the same structure, the same hydraulic principle and the same hydraulic components of the hydraulic equipment, so this method has great limitations and certain blindness.
2, auxiliary method

Diagnose the failure of the hydraulic components of the hydraulic unit with the aid of simple auxiliary parts.

1) The oil blocking method, such as blocking the port and cylinder port of the valve component, can diagnose whether these hydraulic components leak and fail.

2) The artificial reversing method uses the ejector pin to reverse the valve components, and can diagnose whether the reversing valve has such problems as stuck and the spool is not in place.

The auxiliary method can diagnose the hydraulic component without failure, avoid excessive disassembly work, reduce the fault diagnosis time, and facilitate quick diagnosis, especially for; Good practicality

3. Experience method Repair personnel are familiar with the structure and working principle of each hydraulic component by mastering the hydraulic system of hydraulic equipment, and comprehensively analyze and compare the failures of hydraulic equipment on the basis of accumulated experience in repairing hydraulic equipment. And quickly make an accurate diagnosis. In summary, the fault locations and causes of hydraulic equipment generally can be roughly divided into the following five aspects.

(1) improper adjustment of hydraulic components, such as: oil pump, oil motor, sequence valve, directional valve, overflow world, unloading valve, balance valve pressure and flow adjustment is wrong;

(2) The sealing element is damaged or the impurities make the hydraulic component unable to work normally;

(3) The hydraulic components are worn or damaged, such as valve element sealing failure, spring failure, clearance over, etc.;

(4) Failure of the control mechanism (electrical appliance), such as: failure of the relay, poor contact or damage of the button, incorrect installation of the electromagnet, misconnection of the motor phase line, etc., causing malfunction of the hydraulic component or program error;

(5) Failure of auxiliary mechanism, such as improper adjustment or damage of limit switch position, damage of pressure gauge, damage or mis-send of pressure relay, fuel tank filtration problem, etc.

4, sensory method

Diagnose the failure of the hydraulic equipment, namely: “Q”: By asking the operator of the hydraulic equipment, what malfunctions have occurred in the hydraulic equipment, which helps the repair personnel to diagnose the fault;

“Look”: By observing the working condition of the hydraulic equipment, observing the pressure gauge and pressure relay, position sensor, etc., it is possible to diagnose whether a certain hydraulic component works reliably;

“Listening”: By listening to the sound from the hydraulic system and components when the hydraulic equipment is working, it is helpful to diagnose whether the components are working properly. For example, when the cylinder is unloaded, the vibration and noise of the hydraulic system are too large, and the steering valve is operated. When changing direction, the impact is too large, and the sound is normal when the oil pump is running;

“Touch”: By touching, it also helps to diagnose whether the component and system are working properly.

5, section division method

For more complex hydraulic systems, the hydraulic system can be functionally divided into several categories to analyze the location of the fault. The hydraulic system is divided into: pump pressure control loop; system control loop; actuator control loop and other parts. Then, according to the characteristics of the fault, it is determined that the fault occurs in that area and the fault is judged for the area.

6, analysis method

The analysis method is a fault diagnosis method based on the working mechanism of the hydraulic system. The analysis method can solve many hydraulic system failures, but the hydraulic system failure analysis personnel have higher requirements, and must fully understand and be familiar with the working principle of hydraulic components and circuits.

In the fault analysis, the following problems are worth noting: 1) In-depth analysis of the hydraulic system diagram, combined with the relevant electromagnet action table and related circuit diagrams, to figure out the complete working mechanism of the loop, and at the same time, correctly understand the design intention and ideas of the loop, Technical measures and related background. 2) Correspond to the working principle diagram and the real object to form a concrete impression. The pipeline in the hydraulic circuit often has a big difference between the schematic and the actual object. Where possible, the collusion between the valve bores on the valve plate and the blocking relationship should be clarified. These factors are closely related to the subsequent circuit inspection. 3) Refer to the relevant books and materials, find out the basis for judging the characteristics of the hydraulic device, and then judge it. 4) Refer to the relevant book and equipment instruction manual to discuss the failure mechanism and related analytical test methods.

In summary, although the fault diagnosis method has many advantages, it also has disadvantages. Therefore, while applying these methods, we should also pay attention to the modern diagnostic technology of hydraulic equipment failure, and based on modern scientific instruments, continuously improve the scientific, accurate economic and rapidity of hydraulic equipment fault diagnosis technology to ensure that hydraulic equipment can be normal. Run to better serve production.