ring sleeve for cushioning
In the field of valve application, the bushing is inside the valve cover and wraps the valve stem. Generally, DU oil-free bushings use corrosion-resistant materials such as PTFE or graphite for sealing.
Function: protect the shaft, seat hole, prevent DX oil-free bushing from wear; shock absorption, noise reduction; reduce disassembly and maintenance;
Material: An imported THORPLAS can be considered;
Use: no grease, dry running;
Installation: interference fit
Supplement: oil-free bushing, as the name suggests, does not need to add lubricating oil JDB graphite copper bushing and grease, which is convenient in use and maintenance, saving cost, time and expense;
There are several types:
There are many in the market now, there are three main ones:
1. The metal matrix, usually copper and lead, have holes on the surface, and grease is added to the holes; it is supported by a large amount of grease in the holes, and in fact, it needs to be refueled for a long time;
2. Composite bushing, one is steel back + copper powder + PTFE Teflon, and the other is steel back + copper powder + POM polyoxymethylene; it belongs to pressing molding; it is realized by the inner wall material of the bushing, but it is very difficult. Thin, fragile, cannot withstand high pressure;
3. Non-metallic self-lubricating bushings: true self-lubricating; nylon, Teflon, and Cylon
The oil-free bushing is the improvement of the copper bushing. When designing, if the load is light, we will choose the copper bushing and the oil-free bushing.
Most oil-free bushings today are steel plates, with spherical bronze powder sintered in the middle, and some other substances sprayed on the surface, such as a mixture of polytetrafluoroethylene (PTFE) and lead. It has the characteristics of a small friction coefficient, good wear resistance, good corrosion resistance and oil-free lubrication. It is mostly used for sliding parts of various machinery, such as printing presses, textile machines, and fitness equipment hydraulic trucks. Some bushings are specially processed, which can withstand high-speed motion but cannot withstand heavy loads.