Ring set in one of the liner
In the field of valve application, bushing within the valve cover, wrapped around the valve stem, general DU oil-free bushings used ptfe or corrosion materials such as graphite, used for sealing function.

supplement

Role: protect the shaft and hole, don't send DX oil-free bushings wear;Shock absorption, noise reduction;Reduce the reduce the disassembly and maintenance;

Material: an import THORPLAS can consider;

Use: no grease, dry running;

Installation: the interference fit

Supplement: oil-free bushings, just as its name implies, need not add lubricant JDB graphite copper sleeve and grease, convenient in operation and maintenance, saving cost, time and cost;
Several points:
Now there are many in the market, there are three main types:
1, the metal substrate, copper and lead, general surface has a hole, hole add grease;By a large amount of grease inside support operation, in fact, after a long time also need to come on;
2, the composite bushing, one kind is the steel back + + PTFE teflon of copper powder, another is the steel back + copper powder + POM POM;Belongs to pressure molding;By liner wall material in work, but very thin, fragile, cannot afford when pressure;
3, non-metallic self-lubricating bushings: true self lubricating.Nylon, teflon, and acetate

No oil bushing is white copper set of improvement, at the time of design, if we will choose copper sets of light load and oil-free bushings,
Now most of the oil free bushing is steel plate, sintered spherical bronze powder, surface spraying some other substances, such as teflon (PTFE) and the mixture of lead.Small friction coefficient, good wear resistance to corrosive and oil free.More applied to various mechanical sliding parts, such as printing presses, textile machines, machines hydraulic carrier.Some collar is through special craft processing, can withstand high speed movement, but unable to bear the heavy load.
Oilless bearing when I design is commonly at low load low speed 1000 RPM