| 摘要 |
PURPOSE: A spool valve for automatic transmission and a manufacturing method thereof are provided to minimize a decrease in transmission due to hydraulic loss since a thermal expansion coefficient is large, so a gap to a valve body decreases. CONSTITUTION: A spool valve for automatic transmission comprises next steps. An extrusion member is made using Mg alloy whose main component is Mg, to which Al of 7.5-9.5 wt%, Mn of 0-1.15 wt%, Zn of 0~1.5 wt% and other alloy including Fe, Cu, Ni and the like. The extrusion member is processed to form a spool valve shape of a molding member. On the molding member, solution treatment is made for a given time at a temperature of 375-395°C and then oil quenching is made. Aging treatment is made on the molding member thermally treated for a given time at a temperature of 375-395°C.
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