Dimensional Change in Plastic Gears in Vacuum and Some Experimental Results

Because plastic gears possess sufficient self-lubricating ability, operation without lubrication is feasible. Accordingly, plastic gears seem to be most suitable for use in vacuum, where lubricating oil cannot be used. However, with plastic gears, there are also problems pertaining to heat resistance, the occurrence of dimensional change as the moisture contained in the atmosphere dehydrates in vacuum, and so on. For the purpose of applying plastic gears to practical use in vacuum, in this research, the dimensional change in vacuum of various plastic gears which were used in atmosphere was examined, a few operation tests were performed, and the results were investigated.