| 摘要 |
PURPOSE:To eliminate coupling structure between coupling tube and valve casing by inserting a coil spring made of shape-memory alloy from the small diameter step side of coupling tube then heating over martensite transformation point. CONSTITUTION:A coil spring 7 has such diameter as insertable through small diameter step section 4 of coupling tube 3 under martensite transformation point and made of unilateral shape-memory alloy to be deformed to provide large diameter at the temperature higher than martensite transformation point thus to stop a portion at the side of small diameter step section to the small diameter step section 4. When assembling, the coil spring 7 is inserted together with the valve body 5 from the small diameter step section of coupling tube 3 coupled to the valve casing 1 then heated over martensite transformation point thus to energize the valve body 5 in the closing direction. |
