| 摘要 |
PURPOSE: To provide a rolling bearing device capable of withstanding a heat sterilizing treatment and withstanding ultra-high-speed rotation in a lean lubricating environment by constituting a rolling bearing holder which freely rotatably holds the shaft of a handpiece by impregnating the sintered compact of polyimide resin powder having specific ratios, by volume, of open cells with a fluorinated oil. CONSTITUTION: A turbine 5 is mounted at the shaft 4 mountable with a dental cutting tool 3 at its front end and a compressed air introducing path 6 for driving is disposed to face this turbine. The shaft 4 is freely rotatably held by the rolling bearing device 2. The holder of the rolling bearing consists of the material formed by impregnating the sintered compact of the polyimide resin powder having 5 to 20%, by volume, of the open cells with the fluroinated oil. The fluorinated oil is formed of a perfluoropolyether or perfluoroalkyl ether. As a result, the heat sterilization treatment of the rolling bearing device is made possible and the rolling bearing device withstands the ultra-high-speed rotation over a long period of time even in the lean lubricating environment. In addition, the holder mounted thereon does not melt even in the event of the run out of the lubricating oil. |
