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Self-lubricating chains, also referred to as lube-free chains, are commonly found in both roller chain (ANSI Standards, British Standards, and DIN Standards) and conveyor chain varieties, with specialty self-lubricating chains also available. These chains utilize a bush made of an oil-impregnated sintered metal or plastic to provide continuous lubrication to the chain during drive, eliminating the need for further lubrication.〔so that the bearing requires no further lubrication during the whole life of the machine in which it is used, according to (【引用サイトリンク】Porous bearings )〕 == History == While some of the earliest self-lubricating bearings were developed by Chrysler〔"Chrysler engineers developed bearings that were made of metal powders forced together under high pressure and heat (a process known as sintering). The ingredients were pure virgin copper (88.5%), tin (10%), and graphite (1.5%). The sintered bearings were so impregnated with oil — with around one third of their volume being oil — that, in most cases, they needed no service attention after installation, although they were seemingly solid. The bearings were dubbed Oilite ®; Oilite bearings would be used in distributors, generators, starters, and ball joints as well as water pump and clutch pilots," according to 〕 the earliest self-lubricating chains were bushed chains, which consisted of pins, plates, and sintered bushes. The loss in strength of the bush required it to be made extra thick. This made the outer diameter so large that it did not allow enough room for a roller. These bushed chains suffer from the drawback of lower allowable load and tensile strength compared to regular roller chain, and the outer diameter of the bushes do not rotate when engaging a sprocket and may suffer faster wear and damage. While various chain manufacturers offered self-lubricating bushed chain designs based on sintered-bush technology since the 1950s, the world's first〔(【引用サイトリンク】title=Brief History of Lambda Chain )〕 self-lubricating roller chain was developed and launched by a Japanese chain manufacturer in 1988.〔(【引用サイトリンク】title=Lambda Chain )〕 After they made further improvements to the oil impregnation and sintering technologies, they received a patent for their lube-free roller chain, as evidenced by Patent #JP20070237969. In the new design, advancements in powder metal bush technology allowed engineers to design a bush that had a smaller diameter yet was stronger, which allowed room for rollers. These rollers improved performance by allowing the chain to articulate more smoothly into sprockets and protect the sintered bushes. Because of these advancements, the self-lubrication style chains achieved strength on par with regular roller chain, with the added benefit of being lube-free. Powdered metal sintered bearings (in the case of roller chain, the bushes) are self-lubricating because their porosity is impregnated with lubricants during the manufacturing process. In use, frictional heat causes the lubricant to expand and flow out of the pores, forming a film between mating parts. Low coefficients of friction, minimal maintenance and trouble-free service life, low cost, and simple installation are the chief advantages of powdered metal bearings.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Self-lubricating chain」の詳細全文を読む スポンサード リンク
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