| 摘要 |
PROBLEM TO BE SOLVED: To extend a time until a poor full close state or the inability of full close occurs due to the clog of deposit by increasing a deposit accumulation capacity of the inside of a seal ring groove 6 while preventing a seal ring 7 from coming off from the inside of the seal ring groove 6 of a butterfly valve 4 of an EGR control valve. SOLUTION: An inner volume (capacity) of an annular space (groove clearance) formed between the groove bottom surface of the seal ring groove 6 and the seal ring inner diameter surface 34 of the seal ring 7 is increased by forming a section shape of a groove bottom surface forming part 39 forming the groove bottom surface of the seal ring groove 6 in a rectangular shape different from an inner diameter shape of the seal ring 7 and providing four first-fourth groove deep parts 51-54 by digging in the groove depth direction of the seal ring groove 6 deeper than first-fourth groove tops 41-44 (four vertexes). Also, there is no risk for the seal ring 7 to come off from the inside of the seal ring groove 6 since an inner diameter position of the seal ring 7 is positioned by the four vertexes. COPYRIGHT: (C)2008,JPO&INPIT
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