To mold a pressure-reducing chamber with a resin, to increase rigidity, and further to increase an inner volume by enlarging width.
Upper and lower divided resin moldings of an outer hull member 14 are air-tightly sealed to each other. An inner volume can be enlarged without limiting the inside of the outer hull member 14 to the tapered shape from an opening, and further strength can be ensured by applying the dome shape projecting outward. As a division surface 142a is inclined to gradually decline backward to be a plane connecting the neighborhood of a rear part of a top face of the opening 140r and an approximate central section of a rear wall of the outer hull member 14 of the rear wall 140d, the strength can be ensured by ensuring a thickness 141t without thinning an upper case 141. The division surface 142a is constituted of the inclined plane, accuracy can be easily increased, and the air-tightness can be easily kept.
ASHIDA MAKOTO
ISHIZUKA MASANOBU
BETSUYAKU KENJI
| JPS5544781U | 1980-03-24 | |||
| JP2010014295A | 2010-01-21 | |||
| JPH1163806A | 1999-03-05 | |||
| JP2010038498A | 2010-02-18 | |||
| JPS5544781U | 1980-03-24 |
Yuji Toda