What is the impact of hydraulic oil on seals in hydraulic CNC bending machine?

The hydraulic oil in the hydraulic CNC bending machine is used as the working medium in the hydraulic transmission system, which plays the role of energy transmission, conversion and control. At the same time, it also plays the role of lubrication, anti-corrosion, anti-rust and cooling of various parts in the hydraulic system And so on. The seals in the hydraulic system play a role in preventing fluid leakage from the joint surfaces, maintaining pressure, and maintaining energy transfer or conversion.

What is the impact of hydraulic oil on seals in CNC bending machines?

CNC bending machine

The hazards of high oil temperature in the system

1. The viscosity of hydraulic oil decreases

The viscosity of hydraulic oil changes with temperature. If the temperature is too high, the viscosity of hydraulic oil will decrease, which will cause leakage and reduce volumetric efficiency. At the same time, the lubrication performance deteriorates, which leads to increased wear and even sintering.

2. The parts of the hydraulic system expand due to overheating

Because the linear expansion coefficient, heating and heat dissipation conditions of the various components of the system are not the same, the thermal expansion of each part is not exactly the same, and the resulting deformation is also different, which is likely to destroy the original normal fit gap of the relative moving parts, resulting in Increased frictional resistance makes the spool easy to jam. At the same time, the high temperature makes the lubricating oil film thinner and the mechanical wear increases, causing the precision mating surfaces in the components to fail or even become scrap due to premature wear.

3. The oxidation stability and thermal stability of the oil are destroyed

Oxidation stability: refers to the ability of liquids to resist chemical reactions with oxygenates (especially air).

Thermal stability: It is the ability of a liquid to resist chemical reactions at high temperatures.

In the process of use, the oil is oxidized due to the influence of heat, oxygen, and metal materials, which causes the oil to deteriorate. When the temperature and pressure increase, the oxidation speed will increase, and the substances produced by oxidation will increase the corrosiveness to metals.

4. Accelerate the deterioration of seals, shorten their lifespan, and lose sealing performance, causing serious leakage of the system.

5. Impurities are easy to produce. If the oil temperature is too high, it is easy to vaporize, so that the water evaporates, and the components are easy to cause cavitation. The oil oxidizes to form colloidal deposits, which block the filter element and the damping holes in the hydraulic valve and make the system work abnormally.

2. Reasons for high oil temperature

1. The variety and viscosity grade of Anhui Yongya Oil do not meet the requirements.

Each type of hydraulic oil is suitable for working in hydraulic systems in different environments. For example: Long-running hydraulic system should use L-HM anti-wear hydraulic oil.

2. Serious pollution of hydraulic oil

Due to the objective conditions inside and outside, the longer the working time of the hydraulic system is, the longer the working time of the hydraulic system is, the more impurities and dirt will be mixed into the oil, which will damage the accuracy of the matching surface of the hydraulic components and increase leakage. , In severe cases, the component life is short. Especially when the dirt passes through the oil filter, it will be adsorbed on the filter element in the oil filter, causing the oil absorption resistance and energy consumption to increase, causing the oil temperature to rise.

3. The liquid level in the fuel tank is too low

If the amount of oil in the oil tank is too small, the hydraulic system will not have enough flow to take away the heat generated in the system, resulting in an increase in oil temperature.

4. Air is mixed into the system

In the low pressure state, the air forms many small bubbles in the oil. When it moves to the high pressure area, these small bubbles will be instantly crushed by the high pressure oil. The compressed and broken bubbles will release a lot of heat, causing the oil temperature to rise .

5. The oil filter is clogged

Precaution

1. Reasonable selection of oil grades, special hydraulic oil should be used for some equipment with special requirements. For long-term high-load operation and long oil change time, good performance anti-wear hydraulic oil should be selected. At present, the hydraulic system of this unit mostly uses L-HM type 46 hydraulic oil.

2. Periodically replace the hydraulic oil.

3. During the initial operation of the equipment, oil should be injected into the oil hole of the hydraulic pump and the coupling between the hydraulic pump and the motor should be rotated manually for a few laps, so that the pump is filled with oil, so as not to inhale air or rotate at high speed due to lack of lubrication Under the condition, heat is generated, which will increase the oil temperature and even wear the components.

4. Choose an appropriate cooler, the choice of cooler is related to power.

5. Regularly replace the filter element to ensure that the oil is clean and the oil path is unblocked.

Hydraulic technology is developing in the direction of high pressure, high frequency, fast response, guidance, etc. The requirements for media are getting higher and higher, and troubleshooting is more difficult. However, 80% of hydraulic system failures are directly related to hydraulic media. Therefore, the selection of hydraulic media and daily maintenance are very important. Only on this basis can the hydraulic system run more stably and have a longer service life.