| 摘要 |
PROBLEM TO BE SOLVED: To effectively prevent the damaged leaking of a bellows so as to use the bellows until its designed life by sealing a space between a linear motion shaft in the bellows and a bellows flange and disposing a through-hole for communicating the back and forth sides of sealing with each other in the linear motion shaft. SOLUTION: In a linear motion mechanism 1 used for a parallel flat type plasma CVD device or the like, a lip seal 3 is provided between the upper end flange 110 of a bellows 108 and a shaft 106 and a foreign objets floating in a vacuum chamber 100 is prevented from entering the bellow 108. However, if the lip seal 3 is used, a pressure difference occurs between the internal space of the bellows 108 and the vacuum chamber 100 and, during the forward/ backward movement of the shaft 106, pressure fluctuation may occur in the vacuum chamber 100 because of the sealing shortage of the lip seal 3, and thus a through-hole 5 is formed in the shaft 106 for preventing such a pressure change. Thus, the welding bellows 108 is used until its designed life. |
