| 摘要 |
PURPOSE:To improve property of running of molten metal by setting cavity into a die so as to turn a frame body upside down and pouring the molten metal directing the molten metal from a head pipe side toward a rear frame and a down tube. CONSTITUTION:The casting die 50 has the cavity 88 composed of a lower die 80, upper die 82 and core assembly 190. The cavity 88 is made to the position which turns the frame body in the fitted pasture of an auto-bicycle upside down. A main sprue part 94, auxiliary sprue parts 96, 98 are arranged and a gate for the sprue part 94 for supplying the molten to the front side is made to the max. size and gates for the auxiliary sprue parts 96, 98 in the direction from the front side toward rear side are made to smaller in order. The molten metal is run from the front side in order and good balance of solidification is obtd. The heights of the sprues are made so as to become higher from front side to the rear side, and the molten metal is made to flow from the front side. The deterioration of the running as a trouble point in the low pressure casting method, is prevented. |
