JPH0443301Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a nozzle for an injection molding machine that injects a molten synthetic resin material into a mold through the nozzle.

(Prior art and its problems) Conventionally, injection nozzles for injection molding machines include a short nozzle with a short length and an extended nozzle with a long length.

Generally, the former is used by being placed in contact with a sprue opened on the side of the mold, while the latter is used by being inserted into a nozzle hole drilled in the mold, and the tip is placed in contact with a runner or sprue. It is something that will be done.

However, with conventional extension nozzles, as the length increases, unless the diameter is increased, the nozzle body or the needle provided within the body may become deflected or misaligned. It was inevitable that it would grow larger. For this reason, the diameter of the extension nozzle used for stack molds or thick molds becomes considerably large, and a large diameter nozzle insertion hole must also be drilled on the mold side, making it difficult to mold the molded product. The effective area for molding becomes smaller, resulting in larger mold dimensions and the need for a larger molding machine.

Furthermore, when the diameter of the nozzle is made small and its length is made long, the molten resin inside the nozzle is cooled, resulting in a disadvantage that the flow of the resin becomes poor.

(Purpose of the invention) This invention was made to solve the above-mentioned problems, and it prevents the needle body from bending and misaligning, provides an extension nozzle with a small diameter compared to its length, and also provides an extension nozzle with a small diameter compared to its length. The purpose is to facilitate centering of both when connecting to a mold, and to prevent the molten resin from cooling inside the nozzle.

(Means for solving the problem) The present invention is an extension nozzle that is attached to the tip of an injection device and connects the injection device and a mold. It is formed so that it comes into contact with the mold,
A needle is disposed inside the nozzle body so as to be movable by the pressure of the molten resin, and is supported by a plurality of needle support members that project from the inner peripheral surface of the nozzle body toward the center of the resin passage at intervals. It is characterized by a coil heater attached to the outer circumferential surface.

(Example) An example of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, reference numeral 1 denotes an injection device main body, and a cylinder head 2 is integrally attached to the tip of the main body 1. An extension nozzle 3 is screwed into the cylinder head 2. The nozzle 3 is comprised of a substantially cylindrical nozzle body 4, a nozzle head 5 attached to the tip of the body 4, and a needle 6 movably provided within the nozzle body 4.

Further, a lead wire 7 is provided on the outside of the nozzle body 4.
A coil heater 8 connected to the coil heater 8 is disposed over almost the entire length, and the heater 8 is arbitrarily controlled by a control device (not shown).

A heater cover 9 is attached to the outside of the coil heater 8.

A plurality of (two in this embodiment) needle support members 10a, 10b are provided on the inner peripheral surface of the nozzle body 4 at intervals in the length direction.

As shown in FIGS. 1 and 2, the needle support members 10a and 10b have a plurality of support arms 11a and 11b that are formed integrally with the nozzle body 4 and extend in the axial direction of the nozzle body, respectively. The outer peripheral surface of the needle 6 is slidably supported by support arms 11a and 11b, or the first As shown in FIGS. 3 and 3, an annular ring 10b that can be fitted into the inner peripheral surface of the nozzle body 4 is provided, and a plurality of support arms 12a and 12b extending in the axial direction of the ring 10b are connected to each arm 1.
The tips of the needles 2a and 12b are formed so as to be located on an imaginary circle that is equal to or slightly larger than the outer diameter of the needle 6, and the outer peripheral surface of the needle 6 is connected to the support arm 12.
It is slidably supported by a and 12b.

Therefore, the needle support members 10a and 10b are arranged so that the center of the virtual circle is located on the same axis as the axis of the needle 6.

The diameter of the needle 6 on the proximal end side is such that the needle 6 can be moved back by the resin pressure inside the nozzle, with the part supported by the support arms 11a and 11b formed integrally with the nozzle body 4 as a border, on the distal end side of the needle. It is larger than the diameter of.

The annular ring 10b is attached by fitting it into the inner circumferential surface of the nozzle body 4 from the opening at its tip, and then screwing the nozzle head 5, which has a flat tip surface and a hexagonal nut-shaped tip. Fixed. The extension nozzle 3 has contact members 13a and 13b provided at the tip and base ends of the mold 11 via the nozzle head 5 and the base end 4a of the nozzle body, respectively.
is supported by

Further, a desired number of small holes 14 are formed in the nozzle head 5 formed in the shape of a hexagonal nut, and a temperature sensor 16 such as a thermocouple for detecting the temperature of the resin flowing through the resin passage 15 is buried in the holes 14 as necessary. are doing.

The nozzle 5 is formed with a tapered surface 17a that widens from the nozzle hole 17 toward the resin passage 15. (See FIG. 4) Furthermore, a truncated conical surface 6a that decreases toward the tip is formed at the tip of the needle 6, and the conical surface 6a and the tapered surface 1 of the nozzle head 5
7a is formed equally, and the needle 6
The truncated conical end of the needle 6 and the tapered surface 17a of the nozzle head 5 are brought into contact with or separated from each other by moving the nozzle hole 17 forward and backward by an operating lever (not shown), thereby opening and closing the nozzle hole 17.

In order to escape thermal expansion of the needle 6, a slight gap is provided between the tip surface of the nozzle head 5 and the tip surface of the needle 6 at room temperature.

(Function) When the mold clamping device (not shown) is operated to close the mold and the injection device main body 1 is moved toward the mold 11 by a moving device (not shown), the nozzle head 5 and the nozzle main body base 4a are moved to the contact member 13a of the mold 11, respectively. ，
13b, the centering to the mold 11 is easily performed, and the tip surface of the nozzle head 5 is aligned with the nozzle hole 17.
A flat surface is applied so that the sprue (not shown) on the mold 11 side comes into contact with the sprue (not shown). At this time, since the rear end of the needle 6 is pushed by an operating lever (not shown), the truncated cone 6a of the needle 6 comes into contact with the tapered surface 17a of the nozzle head 5, and the nozzle hole 17 is closed. .

Then, when the injection device is activated to start injection, the resin pressure inside the nozzle increases, and the needle 6 moves back due to the difference in diameter between the tip and rear ends of the needle 6, opening the nozzle hole 17. The molten resin in the nozzle body 4 is injected into the mold 11. In this state, a control device (not shown) controls the temperature inside the mold while performing predetermined pressure holding control, and starts cooling and solidifying the resin, and at the same time, the operating lever pushes the rear end of the needle 6 and presses the truncated conical surface. 6a contacts the tapered surface 17a and closes the nozzle hole 17. On the other hand, the resin in the nozzle is heated to an appropriate temperature by the coil heater 8 and the control device.

(Effects) According to the present invention, when the extension nozzle is connected to the mold, the nozzle head and the base of the nozzle body come into contact with the contact member of the mold, so that centering with the mold can be easily performed, and the nozzle can be easily aligned with the mold. A needle that is movable by the pressure of molten resin in a resin passage provided in the main body is supported by a plurality of needle support members that protrude from the inner peripheral surface of the nozzle body toward the center of the resin passage at intervals. By doing so, it is possible to prevent needle deflection and misalignment, and also to reduce the diameter of the needle.As a result, the diameter of the extension nozzle becomes smaller, and the nozzle insertion hole drilled in the mold side also becomes smaller in diameter. It is possible to effectively utilize the area of the molding die to mold products of various shapes. Furthermore,
A coil heater is attached to the outer circumferential surface of the nozzle body, which reduces the diameter of the extension nozzle and prevents the molten resin in the nozzle from cooling and worsening the resin flow even if the length is increased, improving the quality of molded products. It is extremely effective.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of an extension nozzle for an injection molding machine showing an embodiment of the present invention, Fig. 2 is a sectional view A of Fig. 1, Fig. 3 is a sectional view B of Fig. 1, and Fig. 4 is a sectional view of an extension nozzle for an injection molding machine. is an enlarged view of section C in Figure 1. 1... Injection device main body, 2... Cylinder head,
3... Extension nozzle, 4... Nozzle body, 4a...
Base end of nozzle body, 5... Nozzle head, 6...
Needle, 6a... truncated conical part, 7... lead wire, 8... coil heater, 9... heater cover, 10... needle support ring, 10a, 10
b... Needle support member, 11... Mold, 11
a, 11b, 12a, 12b...support arm, 13
a, 13b...Abutting member, 14...Small hole, 15...
... Resin passage, 16 ... Temperature sensor, 17 ... Nozzle hole, 17a ... Tapered surface.

Claims (1)

[Scope of utility model registration request] In an extension nozzle that is attached to the tip of the injection device and connects the injection device and the mold, the extension nozzle is formed so that the nozzle head and the base of the nozzle body come into contact with the mold when the mold is connected, and the nozzle body Inside, needles are disposed movably by the pressure of the molten resin, and are supported by a plurality of needle support members projecting from the inner circumferential surface of the nozzle body toward the center of the resin passage at intervals. An extension nozzle for injection molding machines that is equipped with a coil heater.