Claims
- 1. A method for manufacturing an outer tube of an injector, comprising the step of injecting a molten resin into a cavity defined by a metal mold comprising: a fixed mold having a hole portion having a shape along an outer shape of the injector outer tube consisting of a barrel portion, a taper portion arranged at a front end of the barrel where an injection needle is mounted, and a flange portion arranged at a rear end of the barrel, the fixed mold being provided vertical to a parting line defined by a rear end of the flange portion forming portion; a movable mold for closing the hole portion along the parting line; and a core piercing the movable mold and inserted into the hole portion,
wherein the fixed mold includes a sprue for guiding the molten resin and a runner branching from the sprue; the movable mold includes a cylindrical vacant portion arranged vertical to the parting line and communicating with a portion where the flange portion is formed, and a submarine gate communicating with the runner and connected to an intermediate portion of the cylindrical vacant portion; and the molten resin is injected from the sprue via the runner and the submarine gate into the cylindrical vacant portion and introduced via the cylindrical vacant portion into the cavity.
- 2. The method according to claim 1, wherein the metal mold includes a push pin provided slidably along an inner wall of the cylindrical vacant portion and having a tip end which can proceed up to the parting line; the molten resin is injected when the push pin is waiting at a predetermined wait position which is at opposite side of the fixed mold with respect to a connection portion of the submarine gate; and when the molten resin has become half-molten state, the push pin is made to proceed up to the parting line so as to introduce the molten resin with pressure from the cylindrical vacant portion into the cavity.
- 3. The method according to claim 2, wherein when the molten resin has become insufficient in the cavity, the wait position of the push pin is modified in a direction apart from the connection portion of the submarine gate, so as to inject the molten resin, thereby compensating the insufficient resin in the cavity.
- 4. The method according to any one of claims 1 to 3, wherein the metal mold has: a plurality of hole portions provided in the fixed mold; a plurality of cylindrical vacant portions provided in the movable mold closing the respective hole portions along the parting line and communicating with portions where the flange portions of the respective hole portions are formed; and a plurality of cavities defined by the cores piercing the movable molds and are introduced into the respective hole portions,
the fixed mold has a sprue for guiding the molten resin and a plurality of runners branching from the sprue, the movable mold has a plurality of submarine gates communicating with the respective runners and connected to an intermediate portion of the respective cylindrical vacant portions, and the molten resin is injected from the sprue via the runners and the submarine gates into the respective cylindrical vacant portions and via the cylindrical vacant portions into the respective cavities.
- 5. The method according to any one of claims 1 to 4, wherein the molten resin is one selected from a group consisting of polypropylene, polycarbonate, and polymethylpentene.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2001-202525 |
Jul 2001 |
JP |
|
Parent Case Info
[0001] This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/JP02/05833 which has an International filing date of Jun. 12, 2002, which designated the United States of America.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/JP02/05833 |
6/12/2002 |
WO |
|