| 摘要 |
PURPOSE:To enable to smoothly drive a needle pin with a small driving force by a structure wherein the rear end of the needle pin is axially slidably fitted into a hole, which is provided within a valve body and communicated with the interior of a cylinder. CONSTITUTION:The rear length of a recessed part 54a, to which the fork 15a of a lever 15 arranged in the rear portion of a needle pin 54 at its both sides, is formed longer than the pin 54. In addition, the pin 54 is made so as to have the same thickness throughout the whole length. A hole is bored at the fitting center of the valve body 55 to a cylinder 7 so as to extend the pin 54 into the cylinder 7 by inserting the rear end of the pin 54 in order to reach said rear end into molten resin 6 in the cylinder 7. Due to the structure as described above, the resultant load applied to the needle pin 54 can be reduced by means of the pressure of resin at injection. Further, because consequenty the driving force of the pin can be reduced, the load on the abutting surfaces 54b and 15b or 54c and 15c of the pin and lever becomes smaller, resulting in enabling to prevent the respective abutting surfaces from damaging. |
