The working environment of the pneumatic cylinder tube is very bad, and there are many reasons for the wear. Normal wear is usually allowed for structural reasons, but improper use and repair can cause abnormal wear.
1. Wear caused by construction reasons
(1) The lubrication condition is not good, so that the upper part of the cylinder liner is seriously worn. The upper part of the cylinder liner is adjacent to the combustion chamber, the temperature is high, and the lubrication condition is very poor. The flushing and dilution of fresh air and unvaporized fuel exacerbate the deterioration of the upper condition, causing the cylinder to be in a dry or semi-dry friction state, which is the cause of severe wear on the upper part of the cylinder.
(2) The upper part is subjected to a large pressure, so that the cylinder wear is heavy and light. The piston ring is pressed against the cylinder wall under the action of its own elastic force and back pressure. The greater the positive pressure, the more difficult it is to form and maintain the lubricating oil film, and the mechanical wear is intensified. In the power stroke, as the piston descends, the positive pressure gradually decreases, and the cylinder wear is lighter and lighter.
(3) Mineral acid and organic acid cause corrosion of the cylinder surface. After combustion of the combustible mixture in the cylinder, water vapor and acid oxide are generated. They are dissolved in water to form mineral acid, and the organic acid formed in the combustion causes corrosion on the cylinder surface. The corrosive material is gradually scraped by the piston ring during friction. Dropped, causing deformation of the cylinder liner.
(4) Entering mechanical impurities to increase the wear in the middle of the cylinder. Dust in the air, impurities in the lubricating oil, etc., enter the piston and the cylinder wall to cause abrasive wear. Dust or impurities as the piston reciprocates in the cylinder, the wear of the middle portion of the cylinder is exacerbated by the maximum speed of movement in the middle of the cylinder.