| 摘要 |
PURPOSE:To prevent sealing function from deteriorating when an inner rim at an opening end of a cylinder is crushed. CONSTITUTION:A tip face 12 of a cylinder 11 and a sealing face 17 are connected to each other by a circular protruding face 18. The protruding face 18 comprises a first curve 18a having a radius of curvature Ra, a second curve 18b having a radius of curvature Rb coupling the first curve 18 to the sealing face 17 and a third curve 18c having a radius of curvature Rc coupling the first curve 18a and the tip face 12 (Ra>>Rb>Rc). The first curve 18a is placed so that its virtual extension face crosses respective virtual extension faces of the tip face 12 and the sealing face 17. The second curve 18b is formed of an arc face inscribing the sealing face 17 and the first curve 18a. The third curve 18c is formed of an arc face inscribing the tip face 12 and the first curve 18a. |
