| 摘要 |
<p>PROBLEM TO BE SOLVED: To lighten stress concentration at both ends of a bellows, and to prolong its life without increasing the size of the bellows, by making the spring constant of the central part in the direction of expansion and contraction of the bellows, smaller than those of both end parts in the direction of expansion and contraction. SOLUTION: A movable lever 35 is provided penetrating an end plate (sidewall) 3 and is formed so as to sway with a main shaft 18 being outside a container serving as a fulcrum. And a bellows 6 bridging the sidewall 3 and the movable lever 35 is provided at the penetrating part of the movable lever to seal the inside of the container from the outside. Namely, one end of the bellows 6 is fixed to the movable lever 35, and the other end is fixed to the sidewall 3. Here, the height H2 of the mountain of the bellows 6 at the central part in the direction of expansion and contraction of the bellows 6 is larger than that H1 of its mountain at its end part in the direction of expansion and contraction. In other words, the spring constant of the central part in the direction of expansion and contraction is made smaller than those of the end parts in the direction of expansion and contraction. Accordingly, the central part of the bellows 6 has a softer construction compared to the end parts, and the stress at the end parts of the bellows 6 scatters to the central part, and it becomes possible to lighten stress concentration at both ends.</p> |
