Functions of the support ring and piston ring and their materials
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My understanding is that the main function of piston rings is sealing, while the main function of support rings is guidance (do they also serve to reduce friction?) ). I’m not sure if it’s correct or comprehensive; I hope experts can give me some guidance. Also, is there any difference in the materials of the piston rings and the support rings? (Because their functions are different, I personally feel that the material of the support ring is more inclined to be an anti-friction material.) I hope everyone can share their opinions
Why are so many people looking at it with no one replying? ? ?
This post was last edited by 565026033 on 2012-2-7 at 16:55. We use the same materials; both require wear resistance
Piston rings are components used to seal the gap between the cylinder wall and the piston; they also serve to distribute oil and conduct heat. The basic requirements for piston rings are reliable sealing performance and wear resistance. Support rings, on the other hand, are responsible for bearing the weight of the piston and piston rod, ensuring that the piston does not come into contact with the cylinder during its movement. The same materials are required for both types of rings, materials with good wear resistance. However, since the gap between the piston and the cylinder is relatively small, the effective wear amount of support rings is much less than that of piston rings. Therefore, design requirements dictate that support rings must have even greater wear resistance, and the way to achieve this is by increasing the width of the support rings and reducing their specific pressure.
I agree with what was said on the fourth floor, but piston support rings are also made of beryllium copper and copper
Piston rings primarily serve a sealing function, while support rings mainly serve to support the piston as it moves within the cylinder. The materials of the piston rings and the support rings are usually the same (*this is generally the case, but exceptions exist as well, taking thermal expansion into account). It has now become standard practice to use self-lubricating materials for piston rings and support rings; new machines rarely use cast-iron piston rings or piston rings lined with babbitt. In my opinion, friction always exists between the piston rings and support rings and the cylinder liner; therefore, over time, one of them will definitely get worn out. It just depends on which one is easier to replace. . . The self-lubricating materials used for piston rings and backup rings are mainly filled polytetrafluoroethylene (PTFE). Filled PTFE has a very low coefficient of friction, making it the most widely used material; however, its drawback is that it cannot withstand high temperatures and pressures. Polyether ether ketone (PEEK) is used under high pressure; however, PEEK tends to wear down the cylinder surface more easily, and its elasticity is lower than that of PTFE. Therefore, an elastic ring must be added when using PEEK to make piston rings. Polyimide is a new and relatively ideal material, but it is not widely available at present; its quality is unstable and its price is quite high.
“But since the clearance between the piston and the cylinder is relatively small, the effective wear amount of the support ring is much less than that of the piston ring. What does this mean?
The gap between the piston body and the cylinder is generally quite small, with the unilateral gap being around 2.5 mm. As a result, the effective wear amount of the support ring is less than 2.5 mm. If this wear amount is exceeded, the piston body will start to wear down the cylinder bore. Piston rings, on the other hand, are designed to be much thicker than the support rings; moreover, they do not need to bear the weight of the piston. Therefore, under the influence of gas pressure, they can continuously compensate for wear, which leads to an increase in the clearance between them and a gradual rise in leakage.