| 摘要 |
PURPOSE:To prevent damages such as galling and prolong the life of the injection part by energizing the plunger tip head part in the injection direction by elastic material and forming a filling part of lubricant between the tip head part and tip body front end part. CONSTITUTION:Molten metal is poured through a pouring port 5 and is injected. The injection is accomplished as the cylinder rod 14, plunger tip body 11 and tip head 12 advance to force-feed the molten metal. At this time, a coil spring 15 is gradually compressed by the resistance that it receives from the molten metal 24, along with which the volume of the filling part 17 also gradually decreases and therefore the lubricant 16 in the filling part 17 is subsequently filled into the spacing a between the plunger tip head part 12 and injection aleeve 10 as well as into the spacing b between the plunger tip body 11 and injection sleeve 10. Further, when the molten metal 24 is filled in a die cavity 25, the tip head part 12 receives its final boosting and the filling part 17 is compressed and annihilates. Hence, the lubricant 16 having existed in the filling part 17 is discharged and filled into the spacings a and b to prevent the back flow of the molten metal 24, whereby even lubrication is accomplished. |
