Annular seal element and dovetail groove

(57) The seal element for attaching to summary annular Mizouchi is indicated. This slot has an opening, the 1st and 2nd side walls, and a bottom wall prolonged in the direction of an axis in between that side wall. The side wall is prolonged so that it may approach mutually, as each side wall approaches the above-mentioned opening, respectively, there is, and it forms the Troy Dahl cross section of form. In above-mentioned Mizouchi, the 1st side wall is in contact with the above-mentioned bottom wall on the surface curved inside on the whole. This seal element has annular form and has the surface outside a seal which sees on the Troy Dahl cross section and possesses the 1st and 2nd arc portions and a pair of ばり点. This 1st arc portion contacted the above-mentioned side wall and the above-mentioned bottom wall, and is partially projected from the opening of the above-mentioned slot. Moreover, the 2nd arc portion is complementarily received by a part of surface curved inside the above-mentioned slot. An above-mentioned pair of 型ばり点 are located in the side opposite to the surface outside a seal, and each ばり点 is located in the portion which is separated from the sealed fluid in the surface outside a seal.