Plunger tip, injection device, and injection method

Abstract

A plunger tip includes a main body of the plunger tip. A first cooling chamber is provided at a central region of a tip end of the main body of the plunger tip inside the main body of the plunger tip. A second cooling chamber is provided along an outer peripheral surface of the tip end inside the main body of the plunger tip. The second cooling chamber is configured such that a cooling medium is caused to flow in the second cooling chamber in priority to the first cooling chamber.

What is claimed is: 
     
         1 . A plunger tip, comprising
 a main body of the plunger tip, wherein:   a first cooling chamber is provided at a central region of a tip end of the main body of the plunger tip inside the main body of the plunger tip; and   a second cooling chamber is provided inside the main body of the plunger tip along an outer peripheral surface of the tip end, the second cooling chamber being configured such that a cooling medium flows in the second cooling chamber in priority to the first cooling chamber.   
     
     
         2 . The plunger tip according to  claim 1 , wherein the second cooling chamber is configured such that the cooling medium flows at a timing earlier than a timing of the first cooling chamber. 
     
     
         3 . The plunger tip according to  claim 1 , wherein the second cooling chamber is configured independently of the first cooling chamber and configured such that the cooling medium different from a cooling medium flowing in the first cooling chamber flows in the second cooling chamber. 
     
     
         4 . The plunger tip according to  claim 3 , wherein the cooling medium to flow in the second cooling chamber of the plunger tip is liquid nitrogen. 
     
     
         5 . The plunger tip according to  claim 1 , wherein the outer peripheral surface of the tip end of the plunger tip includes a stepped shape. 
     
     
         6 . An injection device, comprising:
 a plunger sleeve having a cylindrical shape;   the plunger tip according to  claim 1 , the plunger tip being configured so as to be slidable in a cylinder of the plunger sleeve; and   a plunger rod that causes the plunger tip to slide in the cylinder of the plunger sleeve.   
     
     
         7 . The injection device according to  claim 6 , wherein the plunger tip is configured so as to be rotatable about an axial direction as a rotation axis. 
     
     
         8 . An injection method of an injection device including a plunger sleeve having a cylindrical shape, a plunger tip configured to be slidable in a cylinder of the plunger sleeve and including a main body of the plunger tip, and a plunger rod causing the plunger tip to slide in the cylinder of the plunger sleeve, wherein a first cooling chamber being provided in a central region of a tip end of the main body of the plunger tip and a second cooling chamber being provided along an outer peripheral surface of the tip end inside the main body of the plunger tip, the injection method comprising:
 causing a cooling medium to flow in the second cooling chamber in priority to the first cooling chamber;   supplying molten metal into the cylinder of the plunger sleeve; and   injecting the molten metal by causing the plunger tip to slide using the plunger rod while the cooling medium is caused to flow in the first cooling chamber.   
     
     
         9 . The injection method according to  claim 8 , wherein the cooling medium is caused to flow in the second cooling chamber before the molten metal is supplied into the cylinder of the plunger sleeve.