What lubricating oil is used for pneumatic cylinders? How to add lubricating oil to pneumatic cylinders?

What kind of lubricating oil is used for pneumatic cylinders? Knowledge points on selecting cylinder grease


The cylinder is also called a solenoid valve, a pneumatic valve, and a pneumatic actuator. With the development of industrial automation equipment, cylinders are used more and more widely. In the process of promoting industrial automation, cylinders play a very important role. At the same time, with the advancement of science and technology, the requirements for cylinders are also constantly increasing. Mainly reflected in speed, accuracy and lifespan.



Cylinders are divided into ordinary cylinders, typical cylinders, mechanical contact cylinders, rodless cylinders, magnetic rodless cylinders, rack and pinion swing cylinders, etc. During use, the piston inside it is constantly moving in a circular motion, constantly rubbing against the inner wall of the cylinder to generate heat. When compressing air, heat is also generated. In this case, the sealing ring on the piston must be lubricated to slow down the wear of the sealing ring and maintain the sealing performance of the sealing ring to increase the service life of the cylinder. Therefore, lubrication is crucial during the use of cylinders.





Choosing a suitable lubricant is an essential condition for making a cylinder with excellent performance. If the lubrication of the cylinder is not good, the most common problem is air leakage. Air leakage will lead to insufficient power of the cylinder or even complete failure. This problem is usually caused by the cylinder seal. So how to choose a suitable cylinder seal ring grease? We need to pay attention to the following points:



1. Rubber and plastic compatibility of grease: Sealing rings are generally made of nitrile rubber, silicone rubber, and fluorine rubber. If the grease is not selected appropriately, some chemical components in the grease may react with rubber parts, causing the sealing ring to age. , deformation, hardening, cracking, aggravating the wear of the sealing ring. For example, sulfur-containing grease should not be used for nitrile rubber sealing rings;silicone-containing grease should not be used for silicone rubber sealing rings;although fluorine rubber has good chemical inertness and is not prone to chemical reactions, it is expensive. If fluorine rubber can be used Lubrication with grease can maximize its service life and lubrication effect.



2. Low-temperature performance of grease: Because many cylinders have to work and start up in a low-temperature environment, this requires the grease to have good low-temperature performance. In a low-temperature environment, the viscosity of the grease does not change much, and it will not increase the pressure of the cylinder too much. Starting torque. It is generally required that the normal operation of the cylinder will not be affected at -40°C.



3. High-temperature performance of grease: The cylinder will generate high temperatures during operation. If the high-temperature performance is not good, the grease will easily become thinner and drain from the sealing ring or dry directly, losing the lubrication effect and aggravating the sealing ring's damage. wear and tear. Therefore, a good cylinder grease should not be easy to dry out or lose even at a high temperature of 200°C, and it should be able to provide normal lubrication.



4. Use long-life grease: It is not easy to replace the grease during use of the cylinder, especially some small cylinders that require lifelong lubrication. The temperature changes greatly when the cylinder is working, often starting at low temperature and running at high temperature. This requires that the grease must have a long service life while meeting the other conditions mentioned above, be not prone to deterioration, and ensure long-term lubrication to meet the normal operation of the cylinder for a long time.





How to add lubricating oil to pneumatic cylinder


The cylinder piston rod does not need to be lubricated (there is grease lubrication in the sealing ring around the rod).

The oil mist device (the atomizer you mentioned) installed on the pneumatic pipeline uses flowing compressed air to mix with lubricating oil to form an oil mist-like gas that is sent to the cylinder, air motor, solenoid valve, and other pneumatic components. , making its sliding parts lubricated and durable. In this case lubricating oil is beneficial to the pneumatic transmission system. Its lubricating oil materials are: turbine oil No. 1 (ISO VG32), very thin lubricating oil with a viscosity of about 7E° (equivalent to sewing machine oil 5E°~7E°);national standard No. 7 mechanical lubricating oil (viscosity about 7E°) ) is also a more convenient choice. The oil mist can be projected into the pipeline at a distance of about 2M at most for lubrication. And after the oil mist is lubricated, it will be discharged with the air valve and will not remain in the cylinder.

Many current cylinders, air valves, etc. generally have semi-solid grease (or paste grease) sealed in the sliding parts of pneumatic components in advance, which are called non-lubricating components. Therefore, there is no need to provide additional lubricator lubrication in such a pneumatic transmission (must understand this).

If oil mist lubrication is provided for pneumatic components without oil supply, not only is it meaningless, but the very thin oil mist oil slowly dilutes the sealed semi-solid grease and is lost, so refueling is unfavorable. if already provided