Created on:2021-06-03 10:14

Fault types of hydraulic pump and hydraulic motor, general steps and precautions of fault diagnosis

Fault types of hydraulic pump and hydraulic motor, general steps and precautions of fault diagnosis

(l) Fault type is an important part of the hydraulic system. The event or phenomenon that the hydraulic pump and hydraulic motor lose the specified function or reduce its function in the specified time and conditions is called hydraulic fault, also known as failure. The common faults of hydraulic pump include no oil delivery, insufficient oil output, insufficient pressure or pressure rise, abnormal pressure or flow, high noise, abnormal heat, oil leakage of shaft seal, etc. the common faults of hydraulic motor include abnormal speed and torque (too small or too large), large leakage, high noise, etc.

(2) Fault diagnosis and its implementation after the hydraulic pump and hydraulic motor failure, will cause the hydraulic system and even the main equipment of a technical, economic indicators deviate from the normal value or normal state, affect the normal operation and productivity. Therefore, the fault must be diagnosed and eliminated in time. Fault diagnosis is to judge the fault and its causes, the severity of the parts one by one, put forward the repair plan, and make the pump and motor return to normal work by adjusting and replacing, repairing the failed parts and other measures (the pump and motor that cannot be repaired should be returned to the production and sales manufacturers for repair). Obviously, this work needs to be carried out by professional operation and maintenance personnel and technical personnel.

The fault diagnosis of hydraulic pump and hydraulic motor is a professional and technical work. Whether it can be accurate and timely depends on the knowledge level and experience of users and relevant personnel. To do this job well, the relevant personnel are usually required to have certain theoretical knowledge (such as the basic knowledge of hydraulic working medium and fluid mechanics, the structure and working characteristics of pumps and motors), rich practical experience, and understand and master the structure and function of the main engine and the working principle and characteristics of the hydraulic system [such as the form of oil source (the number, quantity or variable of pumps), and the capacity (performance) of the system And the reasonable working pressure of the system.

(3) General steps and precautions for troubleshooting when it is confirmed that the hydraulic pump (or motor) is faulty, the general steps for troubleshooting are as follows.

① Make preparations for fault diagnosis. Through reading the product samples, operation instructions and relevant archives of hydraulic pump or motor, we can master the following information: the structural principle and performance of hydraulic pump (or motor); source and reputation, manufacturing date, main technical performance; operation, original records, faults occurred during use and handling methods, etc. Because the same fault may be caused by many different reasons, and the same fault caused by these different reasons has certain differences, so when dealing with the fault, we should first find out the fault phenomenon, carefully observe, fully grasp its characteristics, understand the operation condition before and after the fault, find out the fault under what conditions, and clarify the relationship with the fault All the factors that affect it.

② Analysis and judgment. On the basis of on-site inspection, the possible causes of the fault are preliminarily analyzed and judged, and the possible causes are preliminarily listed. The matters needing attention in analysis and judgment are as follows.

a. Fully consider the impact of external factors on the system, in the case of finding out that it is not the cause of the fault, and then focus on the internal system to find the cause.

b. When analyzing and judging, we must consider the mechanical, electrical, hydraulic and pneumatic aspects together. We must not consider the hydraulic alone.

c. Distinguish the fault is accidental or inevitable. For the inevitable failure, we should carefully analyze the cause of the failure and thoroughly eliminate it; for the accidental failure, we only need to find out the cause of the failure and deal with it accordingly.

③ Adjustment test. After the above analysis and judgment, the causes of the faults of the hydraulic pump (or motor) that can still be operated are tested by adjusting the pressure, flow rate and action cycle, so as to eliminate the false and retain the true, further confirm and find out the more likely causes of the faults. The adjustment test can be carried out one by one according to the listed fault causes and in the order of first easy and then difficult; if the grasp is not enough, the larger suspected parts can be tested directly, and sometimes the fault can be eliminated by adjustment.

④ Disassembly inspection. Open and check the fault parts which are further identified after adjustment test. When disassembling, attention should be paid to: record the disassembly sequence and draw a sketch, keep the original state of the part, carefully check the relevant parts, and do not touch and wipe the relevant parts with dirty hands or cloth, so as to avoid dirt sticking to the part.

⑤ Deal with the fault. Adjust, repair or replace the corresponding parts of the fault location, do not rush to deal with.

⑥ Retrying and effect testing. According to the requirements of technical specification, handle the fault carefully. After the fault treatment, the test and test shall be conducted again. Pay attention to observe the effect and compare with the original fault phenomenon. If the fault has been eliminated, it is confirmed that the analysis, judgment and treatment of the fault are correct; if the fault has not been eliminated, it is necessary to carry out the same treatment on other suspected parts until the fault disappears.

⑦ Analysis and summary. After troubleshooting, we should make a serious qualitative and quantitative analysis and summary of the fault, so as to draw a correct conclusion on the causes and laws of the fault, so as to improve the ability to deal with the fault and prevent the recurrence of similar faults.

⑧ In the process of fault diagnosis and repair, special attention should be paid to safety, cleanliness and work order.

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