| 摘要 |
<p>The inside of a housing (3) is partitioned into a first pressure chamber (A) on the upper side and a second pressure chamber (B) on the lower side by a rubber diaphragm (6), and a disc-shaped plate (7) is attached to an upper surface (6C) of the diaphragm (6) to form the first pressure chamber (A). Pairs of through-holes (7F) are drilled into a flat pressure-receiving part (7A) of the plate (7) in four locations in a circular direction surrounding the center. When negative pressure is introduced into the first pressure chamber (A), the negative pressure operates between a lower surface of the pressure-receiving part (7A) of the plate (7) and the upper surface (6C) of the diaphragm (6) via the through-holes (7F, 7F) in the plate (7). Consequently, the lower surface of the pressure-receiving part (7A) of the plate (7) and the upper surface (6C) of the diaphragm (6) adhere to each other strongly due to the negative pressure to form a desirable seal between the two members. The seal between the plate (7) and the diaphragm (6) can be improved.</p> |
