JP3889680B2 - Nozzle mechanism of injection molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a nozzle mechanism in a plastic injection molding machine.
[0002]
[Prior art]
As this type of conventional nozzle mechanism, for example, the one shown in Japanese Patent Publication No. 44-25233 exists.
Although not shown specifically, the conventional nozzle mechanism includes a cylinder head that is fixed to the heating cylinder side, a nozzle that is supported by the cylinder head so as to be movable forward and backward, and a spring that biases the nozzle in the forward direction. The nozzle is provided with a slant hole communicating with the material reservoir of the cylinder head. Normally, the nozzle is biased in the forward direction by a spring means, so that the slant hole communicates with the material reservoir. On the contrary, when the tip of the nozzle comes into contact with the mold side with the movement of the heating cylinder, the nozzle moves backward against the biasing pressure of the spring means, so that the oblique hole and the material reservoir Is configured to communicate.
[0003]
In the actual injection molding, when the tip of the nozzle comes into contact with the mold side with the movement of the heating cylinder and the slant hole communicates with the material reservoir, the molten resin passes through the slant hole from the material reservoir. When the injection is completed from the tip of the nozzle hole and the injection is completed and the heating cylinder returns to its original position, the nozzle is again advanced by the biasing force of the spring means, and the communication between the oblique hole and the material reservoir is established. Will be blocked.
[0004]
[Problems to be solved by the invention]
However, in the conventional nozzle mechanism, the nozzle-side oblique hole and the cylinder head-side material reservoir do not communicate with each other except during injection. There is no method other than forcibly retreating against the urging force of the means to make the slant hole and the material reservoir communicate with each other to secure the resin flow path or to remove the nozzle itself. Therefore, in the conventional nozzle mechanism, it has been undeniable that the work is particularly troublesome when changing the material.
[0005]
[Means for Solving the Problems]
The present invention was developed in order to effectively solve the problems of the conventional nozzle mechanism, and includes a nozzle body attached to the cylinder head side, and the nozzle body is located at the inner front end thereof. A nozzle head that retreats upon contact with the mold, a check pin that is fixed to the inner rear end, a valve body that is disposed so as to be capable of moving forward and backward between the check pin and the nozzle head, and the valve body; has a coil spring biasing provided in the direction away both between the nozzle head and a nozzle cover for restricting the advanced position of the nozzle head, said valve body is pressed by a coil spring, the valve A configuration is adopted in which the tip of the check pin comes into contact with the mouth to form a sealing surface.
[0006]
Therefore, in the present invention, when the material is changed, the valve body receiving the urging force of the coil spring is pushed by the resin pressure and moves in the nozzle body toward the nozzle head, so that the seal surface with the check pin Thus, the resin flow path is automatically secured, and the molten resin can flow out from the tip of the nozzle head. Accordingly, there is no need to forcibly retract the nozzle or to remove the nozzle itself from the cylinder head as in the prior art, so that the material change operation can be performed easily.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail on the basis of a preferred embodiment shown in the drawings. A nozzle mechanism according to this embodiment is a cylindrical shape attached to a cylinder head 2 fixed to a heating cylinder 1 as shown in the figure. The nozzle body 3 is provided with a nozzle head 4 which is located at the inner front end of the nozzle body 3 and retracts when contacting the mold, a check pin 5 fixed to the inner rear end, and the check pin 5 And a collar-shaped valve body 6 disposed in an intermediate portion between the nozzle head 4 and the nozzle head 4 so as to be movable back and forth, and provided between the valve body 6 and the nozzle head 4 in a direction of separating the four and six. The coil spring 7 to be urged and the nozzle bed cover 8 that regulates the forward position of the nozzle head 4 are provided.
[0008]
The nozzle head 4 has a slightly larger diameter at the rear end side that forms one receiving seat of the coil spring 7 and abuts the large diameter portion against the nozzle bed cover 8 so that the advance position thereof is set. When it is regulated and comes into contact with the sprue bush 9 of a mold (not shown), the nozzle body 3 is set so that it can be retracted by δ.
[0009]
In addition, the valve body 6 has a valve opening 6a on the rear end side that forms the other receiving seat of the coil spring 7, and the tip of the check pin 5 is brought into contact with the valve opening 6a of the valve body 6. Thus, the seal surface is set so as to be formed between the valve port 6 a of the valve body 6 and the tip of the check pin 5. In the figure, reference numeral 10 denotes a sealing material provided at the attachment location of the nozzle body 3 and the cylinder head 2.
[0010]
Therefore, under the nozzle mechanism according to the present embodiment, at the time of injection, when the tip of the nozzle head 4 comes into contact with the sprue bush 9 on the mold side as the heating cylinder 1 moves, the nozzle head 4 However, in this state, the molten resin pressure in the material reservoir on the cylinder head 2 side is reduced by the amount of the molten resin pressure of the coil spring 7 against the biasing force of the coil spring 7. As shown in FIG. 1, the valve body 6 is pushed in the direction of the nozzle head 4 against the urging force of the coil spring 7 so as to overcome the urging pressure. Open the face. Accordingly, since a resin flow path is secured by this, the molten resin passes through the inside of the valve body 6 and is injected from the nozzle hole 4a of the nozzle head 4 into the mold.
[0011]
When the injection is completed and the heating cylinder 1 returns to the original position, as shown in FIG. 2, the nozzle head 4 is now pushed to the forward position regulated by the urging force of the coil spring 7. At the same time, the valve body 6 is also pushed in the direction of the check pin 5 by the urging force of the coil spring 7, and its own valve port 6a is brought into contact with the tip of the check pin 5 to completely block the resin flow path.
[0012]
In this case, since the operation region in which the nozzle head 4 moves forward by δ is set, when the inner diameter of the nozzle body 3 is D, the internal volume on the front end side of the nozzle body 3 is πD. ^2/4 × with up by δ min, by down the internal pressure of the front end portion of the nozzle body 3, it becomes possible to absorb the thermal expansion amount of the resin, even the resin leakage from the nozzle head 4 side effective Can be prevented.
[0013]
In addition, when changing the material, as shown in FIG. 3, the nozzle head 4 itself is pushed to the advanced position regulated by the urging force of the coil spring 7 as in the weighing, but as in the injection, Since the molten resin pressure in the material pool on the cylinder head 2 side overcomes the biasing pressure of the coil spring 7, the valve body 6 is also pushed toward the nozzle head 4 against the biasing force of the coil spring 7, and the check pin The sealing surface formed between the 5 tip portions is opened.
[0014]
Accordingly, since the resin flow path is secured by this, the molten resin passes through the inside of the valve body 6 and automatically flows out from the nozzle hole 4a of the nozzle head 4, and new resin is heated to the heating cylinder. 1 will flow into. As a result, in the present embodiment, there is no need to forcibly retract the nozzle or remove the nozzle itself from the cylinder head as in the prior art, so that the material changing operation can be performed easily. It becomes.
[0015]
【The invention's effect】
As described above, according to the present invention, when the material is changed, the valve body receiving the urging force of the coil spring is pushed by the resin pressure and moves in the nozzle body toward the nozzle head by adopting the above configuration. Since the sealing surface with the check pin is opened, the resin flow path is automatically secured, and the molten resin can flow out from the tip of the nozzle head. Accordingly, there is no need to forcibly retract the nozzle or to remove the nozzle itself from the cylinder head as in the prior art, so that the material change operation can be performed easily.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part showing a state of an injection of a nozzle mechanism according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part showing a state during the measurement.
FIG. 3 is a cross-sectional view of a principal part showing a state when the material is changed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heating cylinder 2 Cylinder head 3 Nozzle main body 4 Nozzle head 4a Nozzle hole 5 Check pin 6 Valve body 6a Valve port 7 Coil spring 8 Nozzle head cover 9 Sprue bush 10 Sealing material

Claims (1)

A nozzle body mounted on the cylinder head side, the nozzle body positioned at the front end of the nozzle and retracted when contacting the mold; a check pin fixed to the inner rear end; and the check pin A valve body disposed in an intermediate portion between the nozzle heads so as to be capable of moving back and forth; a coil spring provided between the valve body and the nozzle head and biasing them away; and advancement of the nozzle head A nozzle head cover for regulating a position, wherein the valve body is pressed by a coil spring, and a tip end of a check pin comes into contact with the valve port to form a seal surface, the nozzle of an injection molding machine mechanism.

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