MOTOR-OPERATED VALVE

PROBLEM TO BE SOLVED: To easily and surely execute welding work, and improve reliability of a valve by forming a copper dispersion layer on a joint part of a cover shaped member and a valve main body, joining joint parts of the valve main body and the cover member with each other by means of an inter-furnace brazed welding method, and joining joint parts of a can and the cover member with each other by means of a TiG welding method. SOLUTION: Dispersion layers of copper are formed on an inner hole 33a of a cover member 33 and an inner lower surface by means of metallize process and the like. The copper dispersion layers are formed in such a way that heating is carried out in a hydrogen atmosphere after paste copper brazing is coated on a prescribed portion. An inner hole 33a of the cover member 33 is fitted and calked to an upper annular projection piece 20a of a valve main body 20, and leading tubes 24, 25 are inserted and fitted into a side surface and lower surface of the valve main body 20. An inter-furnace brazed welding method is carried out in a non-oxide atmosphere, and brazed welding parts A1, A2, C, D are integrated by means of a silver brazed welding method. An end of an opening part 32a of a can 32 is engaged with an upper step difference shaped part 33b of the cover member 33, its circumference B is TiG-welded.