| 摘要 |
PROBLEM TO BE SOLVED: To improve corrosion resistance and wear resistance of the valve stem and the bearing of an exhaust brake device and to decrease the occurrence of friction between the valve stem and the bearing. SOLUTION: An exhaust brake device 1 comprises a valve body 3 arranged in the exhaust pipe of an engine and forming a part of its exhaust gas passage 2; a valve stem 5 which is disposed at the internal part of the valve body 3 and on which a valve element 4 to open and close the exhaust gas passage 2 is mounted; and bearings 6 and 7 arranged at the valve body ;3 to rotatably support the valve stem 5. Elements, such as Cr, B, V, and Nb, are diffused and penetrate the whole of the surface of the valve stem 5 and the whole of a surface containing the inner surfaces of the bearing holes of the bearings 6 and 7 through a high temperature salt bath diffusion treatment method and a cured layer formed of an inorganic material, such as a carbide, a boride, and an oxide, is formed.
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