| 摘要 |
PROBLEM TO BE SOLVED: To restrain the development of blow-holes at the forming by die casting. SOLUTION: In the method for forming, by die casting, a tubular die cast formed product 4 provided with a peripheral wall 5 formed in a cylindrical shape at the periphery of a center line 5a and an end surface wall 7 closing a chamber 6 in the peripheral wall 5 at the end side of this peripheral wall 5, a sprue forming part, a peripheral wall forming part, an end surface wall forming part and a partially pressurized head forming part projected from the end surface wall forming part are mutually and integrally formed by the die casting by pressing molten metal into a cavity through the sprue in the die. When the molten metal is formed by the die casting, after almost solidifying the spurue forming part and before completing the solidification of the peripheral wall forming part, end surface wall forming part and the partially pressurized head forming part, a pressurizing hole 9 is formed to this partially pressurized head forming part. This tubular die cast formed product 4 is used for a stock of an outer tube utilized as a shock absorber which is a component of a suspension system of a motorcycle.
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