The influence of hydraulic oil on seals in Hydraulic plate bending machine

Views: 206     Author: DURMAPRESS     Publish Time: 2020-12-16      Origin: DURMAPRESS


The influence of hydraulic oil on seals in Hydraulic plate bending machine

The hydraulic oil in the Hydraulic plate 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, corrosion prevention, rust prevention and cooling of various parts in the hydraulic system. 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.

1. The harm of high oil temperature in the system

1. The viscosity of hydraulic oil decreases

The viscosity of CNC bending machine 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 Plate Bending Machine expand due to overheating

Because the linear expansion coefficient, heating and heat dissipation conditions of each component 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 matching gap of the relative moving parts, resulting in The frictional resistance increases, making the valve core easy to jam. At the same time, the high temperature thins the lubricating oil film and increases mechanical wear, 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 system leakage.

5. It is easy to produce impurities, and the oil temperature is too high, which 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 oil type and viscosity grade 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 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, causing the oil temperature to rise.

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 blocked.

3. Preventive measures

1. Reasonably select oil grades, and special hydraulic oil should be used for some equipment with special requirements. For long-time high-load operation and long oil change time, good performance anti-wear hydraulic oil should be selected. At present, most of the hydraulic system of this unit 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. Heat is generated in the state, 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, rapid response, guidance, etc. The requirements for the medium are getting higher and higher, and troubleshooting is more difficult. However, 80% of the failures of the hydraulic system are directly related to the hydraulic medium. 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.

Synchronization framework:


Synchronization framework of this machine consist of main bearing , pendulum rod ,joint bearing ,reasonable structure , Dose not need to adjust, get with guarantee higher fold curved precision.


The shelf of back gauge range

   The machine has the electrically operated back gauge range disposition, press work table's button to be possible to cause he shuttle and to note the data by counter. The machine’s hand wheel can satisfy the gauge range position. The shelf of gauge range can go high and down, first, loosen the bolt of fluctuation lead screw nut and upper fasten-nut, in order to round the upper nut, the  lead screw go high-and-down can make the back gauge range go high-and-down., after adjustment, fasten it according to the former way.

    The adjustment of slide stroke 

    The adjustment of slide stroke achieves through the control cylinder piston travel, put the   lead screw and nut of tailor-made trapeziform screw thread into the two oil cylinder, change the position to change the piston rod’s interval. Load adjusting knob in the electric appliance box, through the control in cylinder electric motor’s back and forth revolution to realize.

    Attention: The slide plate can be adjusted in the upper end-point, the data-sheep in the front of it shows, certainly cannot the over-travel adjustment avoid damaging electrical machinery.



   The top die installs on the slide, depending on pressure board to fix it. (Has the different length partition top die, according to working piece’s request to composite certain width, bend seal frame shape components for user special orders).

   The nether mould installs the worktable by adjustment bolt, use the handle (22) (23) to make packing block shuttle with the nether mould, in order to aim at the center of top die.

    The flying rings (21) used as lifting nether mould, hang in nether mould bolt or put into the toolbox.



1. Put the power supply of three-phase AC 380v,50hz and ground electrode into the inside of electric.

Adjustment and operation

1. Put the three-phase power source to the advance wire terminal of electric box, let SA3 circumvolve to “0” of the operation panel. Close the power source switch of electric box , the machine power source already put through, then closes the box gate.

2. In the operation panel operate pump electrical machine in short time, observe the electrical machinery’s change is correct or not, if need to proofread, please change power’s advance wire phase. Certainly don’t change inside connection.

3. After operating several minuets of pump electrical machine, adjust pressure holded time relay KT48 to the small position. let SA3 circumvolve to “The spot move” , step on the button “down”

Then the slide makes the movement of “quick down”. As a result of time relay’s effect, the slide shall stop after moving down a distance, make it go on moving down, need to loosen foot switch to step on again, KT48  can adjust pressure holded time , step on the foot switch“up”,the slide stop at dead center.

4. After above finished, let SA3 circumvolve to “single”, step on the foot switch“down”in series, the slide go down and keep the pressure,  after guaranting pressure time finished, the backhaul of hydraulic pressure discharge automatically, the length of guaranting pressure time adjust KT48 time relay. later loosen foot switch, the slide go back above end-point ,SA3 circumvolve to “continuous”, step on the foot switch “down”, the slide reciprocal remove high and low, step on the foot switch“up”, it stop in above end-point.

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