How do piston rings fit to the cylinder wall?
Thread Content
How do piston rings fit to the cylinder wall? It turns out that the reading said that it is like the opening of the piston ring, which makes it elastic and fits itself to the inner wall of the cylinder. Later I heard that it was due to the pressure of the medium leaking into the cylindrical surface of the piston ring, which pressed the piston against the inner wall of the cylinder. I repaired one in the past two days. There is a wave spring leaf installed under the piston ring, that is, in the piston groove, which is basically as long as the piston ring. This spring bar holds the piston ring open and close to the cylinder. Which one is scientific?
The support ring is what you call the wave spring leaf.
In principle, the piston is pressed against the inner wall of the cylinder by the pressure of the medium leaking into the cylindrical surface of the piston ring. The greater the pressure, the tighter the piston ring and the cylinder fit. However, springs and other measures are added for reliability.
The two forces you mentioned exist. The elastic force of the piston ring itself provides a preload force, and the medium pressure strengthens the force against the piston cylinder.
The piston ring itself has its own elasticity and has a certain preload force during assembly. The medium is filled between the ring and the ring groove, which enhances the sealing performance and the lubrication performance of the ring surface.
The principle is to rely on medium pressure to press the piston ring against the inner wall of the cylinder. The wave spring leaf is a strengthening measure and is safer. Just like the earliest reciprocating machines did not have oil injectors, weren't they basically added later?
The first two understandings you mentioned are both correct, but they only cover part of them. The corrugated sheets in the back are just for reinforcement, so the three together are suitable.
This post was last edited by Erdo on 2012-2-28 23:27 Piston rings generally require three forces to work: 1. The higher temperature in the compression cylinder will cause the piston ring to expand (this is why the piston ring will have a gap. Of course, the gap can also facilitate installation) 2. The air pressure difference on both sides of the piston ring seal is obvious. The high-pressure gas uses the pressure difference to "press" the piston ring from two directions. One direction is to axially press the piston ring against the piston ring groove wall, so that the piston ring is close to the groove wall on the side with less pressure. The second direction is from the inside of the piston ring (that is, the concentric inner circle side of the piston ring as a whole, that is, the "small mouth" in the "back" shape. I don't know how to say this, can you explain it clearly. ) Use the pressure difference to push the piston ring toward the cylinder wall. The pressure difference in two different directions seals the gas in the axial direction (the first direction) and the radial direction (the second direction) respectively. 3. The inner wall of the piston ring (the concentric inner circle of the entire piston ring) will have a spring to "assist" the pressure difference and thermal expansion, so that the piston ring can better fit the inner wall of the cylinder. When sealing high-pressure gases, spring assistance is often not used. When sealing at low pressure, the pressure difference is not enough to make the piston ring fit better with the cylinder wall, so spring assistance is needed. I hope it helps you. If there is anything wrong, you are welcome to exchange ideas with friends. * .