| 摘要 |
PROBLEM TO BE SOLVED: To reduce a clearance between a peripheral part of a valve element 4 and a tube wall of an exhaust gas passage, while preventing a contact of the valve element 4 with the tube wall of the exhaust gas passage due to thermal expansion, in an exhaust valve throttle valve provided with a rotary center shaft 12 of a valve shaft 5 set in a position displaced from the center axis of the exhaust gas passage. SOLUTION: Two recessed parts 11 are symmetrically formed by cutting a surface of the valve element 4 in a position on the passage center axis side than the rotary center shaft 12 and wherein a peripheral part of the valve element 4 faces to an edge part 9, in which an insert hole 8 of the valve shaft 5 is opened in the exhaust gas passage. In this position, a distance between the peripheral part of the valve element 4 and the edge part 9 becomes the minimum, and clearance between the peripheral part of the valve element 4 and the tube wall of the exhaust gas passage 2 when closing the exhaust throttle valve can be reduced, while preventing a contact of the valve element 4 with the edge part 9 due to thermal expansion, by providing the recessed parts 11 to increase the clearance in this position. COPYRIGHT: (C)2006,JPO&NCIPI
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