| 摘要 |
PROBLEM TO BE SOLVED: To enhance productivity and the quality of a resin molded product by preventing the generation of a leaked molding resin. SOLUTION: This valve structure of an injection molding cylinder is equipped with a cylindrical valve main body 1 having a passage 2 of a liquid molding resin C formed thereto, the nozzle orifice 3 formed to the outlet end part of the passage 2, the valve seat formed between the passage 2 and the nozzle orifice 3, the valve stem 5 loosely fitted in the passage 2 coailally, the valve disc 6 formed to the end part of the valve stem 5 to be brought into contact with the valve seat 4 under pressure, the needle part 7 protruding from the leading end part of the valve disc 6 to be inserted into the nozzle orifice 3 and the back flow groove 7a of the liquid molding resin formed to the needle part 7. In a weighing process after the injection of the liquid molding resin is completed, when the valve disc 6 is brought into contact with the valve seat 4 under pressure to cut off the resin, the liquid molding resin remaining in the nozzle orifice 3 is allowed to flow backward toward the passage 2 of the valve main body 1. |
