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Your location: Home > Related Articles > Interpretation of some vane pump failure problems-

Interpretation of some vane pump failure problems-

Author:QINSUN Released in:2023-05 Click:118

The causes of vane pump failure usually result in: loud noise, pressure swing, system pressure drop, no pressure and high oil temperature in the system.

A. The main reasons for vane pump noise are as follows:

1. When the vane pump is working, it sucks in air (air enters the pump body)

First check if there are a lot of air bubbles coming out of the oil tank. If so, you can confirm that the vane pump sucks air when it works, check whether the hydraulic oil is sufficient, the filter is deformed, or the amount of oil is not sufficient (the direct method is to clean the hydraulic oil. If there is no problem, temporarily remove the filter screen to see if the fault can be eliminated); then check if there is a problem with the gasket of the oil inlet pipeTHE. Check if the seal is aged and damaged. If this is a new pump, after the above problems are eliminated, the pump body casting may have some holes.

Second, the pump core parts can wear out. Check the pump core parts to see where the problem is. Generally, it is the upper and lower oil distribution plates, rotor, stator wear, blade breakage and other phenomena.

1. The reasons for upper and lower oil distribution plates and rotor wear are as follows:

A. Pump oil absorption vane pump is insufficient (the oil suction height of the oil pump is too high: generally not more than 500mm, when first started The pump body is not filled with hydraulic oil, and the pipe oil inlet is seriously sucked);

B. Hydraulic oil is seriousment polluted, forming large chemical particles, the filter screen is broken, and foreign matter enters the pump body, causing wear.

C. The mounting space between the oil distribution plate and the rotor and blades is too small. Since the pump core parts materials are inconsistent for different purposes, the coefficient of thermal deformation are also different. The higher the temperature, the greater the difference. This can cause direct friction between parts (this phenomenon manifests itself in the short period of time when the vane pump is first used).

D. The output shaft between the vane pump output shaft and the motor is not concentric or resists, which will cause the core rotor to beat and eccentricity of the pump during operation. This situation results in unilateral wear of the distributor plates.upper and lower oil tion.

2. The reasons for stator wear and blade fracture are as follows:

A. System oil temperature is too high (usually controlled under 60 degrees Celsius), which causes the friction surface between the stator and the blade The protective oil film cannot form, and the direct friction between the blade and the stator (high pressure area) is easy to cause wear during operation (the phenomenon is that there are wavy wear marks in the high pressure area of ​​the stator).

B. The hydraulic oil is seriously polluted, forming large chemical particles. The filter screen is broken and foreign bodies enter the pump body, which leads to partial rupture of the vanes and wear of the stator (not only in the high pressure area).

C. The hydraulic oil is too viscous and the blades are not smooth when cutting.work, that is, they cannot be thrown in time, resulting in uneven force on some blades and fractures.

D. Improper material selection and heat treatment of stator and vanes. If the heat treatment of the blades is too harsh, they will lack toughness. When the working pressure difference of the vane pump is too large, the vanes may not resist breakage due to the impact of pressure (mainly reflected in the vane pump with the same specification and large displacement, because the larger the displacement, the larger the working force area of ​​the blade), the broken fragments will directly damage the stator, and because the blade is too big hard and cause early wear in the high pressure area of ​​the stator.

3. The bearing is loose and the shaft seal is leaking for the following reasons:

A. The vane pump output shaft is not concentric.e with the motor output shaft when installing (the motor output shaft is deformed, the coupling Non-concentric, the positioning gap of the vane pump is too large, the screws of installation and fixing are not tight, etc.) or support each other, the radial force is too large or jumps (rough running) when the vane pump is running, and the bearing and shaft seal are damaged, if there is is not handled in time, the pump core parts will be worn out and scrapped.

B. Worn motor bearing. This phenomenon cannot be judged when the vane pump has no load. It is normal when there is no load. Swing and damage bearings and shaft seals.

C. Incorrect assembly, because the vane pump rotates at high speed when it is working, if it is assembled incorrectly (not installed in place or the shaft package is off), it will easily cause damage.

B. Pressure swing means that when the vane pump is working, the system pressure is unstable. As long as the oil pump does not make abnormal noise, it should be the problem of the total pressure valve (relief valve), which should be checked whether the total pressure valve spool is worn, and whether the cushioning is blocked by a foreign body; If the pressure fluctuates due to wear of the pump core parts, there will be abnormal noise when the oil pump is working.

C. The system pressure drop means that the vane pump can reach the predetermined pressure when it works, and the pressure will gradually drop when it works, which will cause the system to not work normally. If this phenomenon occurs in the newly installed pump, it must be caused by a leak in the system control valve or by too high an oil temperature. If the problem above isproduct after a period of use, check whether the upper and lower oil distribution plates are worn (very flat wear), whether the gap between the upper and lower oil distribution plates is too large, the temperature of the oil is too high (the mucous membrane can not form self-sealing oil), and the control valve leakage will cause the system pressure drop.

D. No pressure means that there is no pressure in the system when the vane pump is running. First check whether the hydraulic oil is drained from the vane pump. If not, check if the running direction of the oil pump is correct. The motor and the vane pump If the connection between the couplings is normal, if the positioning screws of the shaft are tight and working, if the vanes cannot be ejected due to the high viscosity of the hydraulic oil and can\'t workoperate normally; check whether the pump core impeller and blades are burnt and cannot be discarded for normal operation, loosen the oil outlet pipe joint to see if there is hydraulic oil coming out. If so, this proves that the pump is basically in good condition. The problem should be that the control valve is seriously leaking and the total pressure valve (relief valve) is invalid.

D. The reason for the high temperature of the system oil must be that the system pipes are too small, the pressure is too high, the hydraulic oil cannot be discharged in time, and the cooling system does not meet the requirements, resulting in the phenomenon of oil trapping in the vane pump, which results in The oil temperature of the pump body and the system is too high. According to the actual situation, increase the system pipeline or reduce the pump displacement.

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