| 摘要 |
PURPOSE:To improve sealing performance by cutting only the part of the bottom part where a dovetail groove contacts with an O-ring, in the circumferential direction of the O-ring, so that the mark due to the cutting work coincides with the circumferential direction. CONSTITUTION:Only the part of the bottom surface 3 where a dovetail groove contacts with an O-ring is cut in the circumferential direction of the O-ring on a basic member 5, and the sectional surface is formed into rectangular form. Then, the both side surfaces 1 and 2 are cut to form a dovetail groove. Therefore, the mark of the cutting work is formed in the circumferential direction, and the mark in the direction of pressure difference is not formed. Since the mark in the finished state on the part where the dovetail groove contacts with the O-ring and securing the airtightness is necessary crosses at right angles to the direction of pressure difference, the sealing performance can be improved. |
