| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an engine valve having metallic sodium enclosed therein, which allows metallic sodium to be easily enclosed inside the engine valve. <P>SOLUTION: The method is provided for manufacturing an engine valve V by sequentially subjecting a stem S having a hollow part H to drawing processing by using a series of dies D1, D2, Dx, Dx+1, and Dn so that the outer and inner diameters of the stem S are miniaturized step-by-step, and that the stem S is thereby molded to a desired size. In the processing, the stem S is subjected to the drawing processing until the inner diameter of hollow part of the stem S reaches a specific size (Steps S11 to S15); metallic sodium Na in the form of a solid block is inserted into the hollow part H of the stem S (Step S16-1); a protective agent P made of solid paraffin or naphthalene is also inserted into the hollow part H of the stem S so as to form a barrier between the metallic sodium Na and the atmosphere (Step S16-2); and the stem S is further subjected to a cold drawing processing (Step S17 and S18). <P>COPYRIGHT: (C)2012,JPO&INPIT |
