JP3029559B2 - Injection nozzle temperature controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device for an injection nozzle.

[0002]

2. Description of the Related Art Conventionally, in an injection device of an injection molding machine, a screw is disposed in a heating cylinder so as to be rotatable and advanceable and retractable, and the screw can be rotated and advanced and retracted by driving means. It has become. Then, at the time of the measuring step, the screw is rotated backward while rotating, the resin dropped from the hopper is melted and stored in front of the screw head, and at the time of the injection step, the screw is advanced and injected from the injection nozzle.

FIG. 2 is a sectional view of a main part of a conventional injection device. In the figure, reference numeral 11 denotes a heating cylinder, and the heating cylinder 11 has an injection nozzle 1 at the tip (left side in the figure).
Has zero. A screw 12 is provided in the heating cylinder 11 so as to be rotatable and movable back and forth, and the screw 12 can be rotated and advanced and retracted by a driving means (not shown). In addition,
Usually, an injection cylinder, an electric motor or the like is used as the driving means.

[0004] The screw 12 has a screw head 21 at the tip. The screw head 21 extends rearward (to the right in the drawing) inside the heating cylinder 11,
At the rear end, it is connected to the driving means. A spiral flight 15 is formed around the screw 12, and a groove 16 is formed between the flights 15.

[0005] A resin supply port 17 is formed at a set location of the heating cylinder 11.
The hopper 13 is fixed to 7. The resin supply port 17 is
The screw 12 is formed at a position corresponding to the rear end of the groove 16 in a state where the screw 12 is located at the most forward position (left side in the drawing) in the heating cylinder 11. Therefore, when the driving means is driven to rotate backward while rotating the screw 12 at the time of the measuring step, the pellet-shaped resin 14 in the hopper 13 falls and the heating cylinder 11
And is advanced in the groove 16.

Further, a heater (not shown) is provided around the heating cylinder 11 so that the heating cylinder 11 can be heated by the heater to melt the resin 14 in the groove 16. Therefore, when the screw 12 is rotated backward by a predetermined amount, one shot of the melted resin 14 is stored in front of the screw head 21.

Next, during the injection step, when the driving means is driven to advance the screw 12, the resin 14 stored in front of the screw head 21 is discharged from the injection nozzle 1.
It is injected from 0 and is filled (balanced) in a cavity space of a mold (not shown). Next, the injection nozzle 10 will be described. FIG. 3 is a sectional view of a conventional injection nozzle.

In the drawing, 10 is an injection nozzle, 22 is a nozzle body, 23 is disposed around the nozzle body 22,
A nozzle cover forming an annular space 24, and a resin passage 25 formed in the nozzle body 22. Since the injection nozzle 10 having the above configuration needs to be brought into contact with a mold (not shown) at the time of the injection process, the diameter is formed small so that it can be inserted deeply into the mold. Then, a temperature control device (not shown) is provided so that the molten resin 14 (FIG. 2) is not easily solidified, and the injection nozzle 10 can be heated together with the heating cylinder 11 by the temperature control device. It has become.

Further, the inside of the space 24 around the nozzle body 22 is divided into a zone A on the tip side of the injection nozzle 10 and the injection nozzle 1.
0, the coil heater 27 is disposed in the zone A, the band heater 28 is disposed in the zone B, and the temperature of the injection nozzle 10 is detected by thermocouples 29 and 30. The temperature is controlled precisely.

[0010]

However, in the conventional temperature control apparatus for an injection nozzle, the band heater 28 is used as the heating means in the zone B.
When the band heater 28 is removed, a lead wire (not shown) may be cut. Therefore, it is conceivable to use a coil heater as the heating means in zone B.
Therefore, it is necessary to wind the coil heater on the zone B side so as to cross the wiring of the coil heater 27. Therefore, since the diameter of the coil heater on the zone B side is increased at a portion crossing the wiring of the coil heater 27, the diameter of the nozzle cover 23 is increased accordingly, and the injection nozzle 10 is also enlarged.

Further, one coil heater is connected to zones A and B.
It is conceivable that the heating amount between the zones A and B may be made different by disposing the coils between the zones A and B by reducing the pitch of the windings in the zone A and increasing the pitch of the windings in the zone B. If a small pitch portion and a large pitch portion are formed in the winding portion of the coil heater, the workability is deteriorated and the cost is increased.

Further, when the amount of heating in the zones A and B is changed according to the magnitude of the pitch of the windings, when the current flowing in one of the zones A and B is determined, the current flowing to the other winding is determined. Since the flowing current is determined in conjunction, the temperatures in the zones A and B cannot be controlled independently. The present invention solves the problem of the conventional injection nozzle temperature control device, can control the temperature of each zone independently and precisely, can reduce the size of the injection nozzle, and reduce the cost. It is an object of the present invention to provide a temperature control device for an injection nozzle capable of reducing the temperature.

[0013]

Therefore, in the temperature control apparatus for an injection nozzle according to the present invention, an injection nozzle in which a plurality of zones are set in order to control the temperature independently of each other, And a heating tube wound therearound.
The heating tube includes a plurality of heating means for independently controlling the temperature of each zone, and each heating means includes a heating element at a portion corresponding to the zone.

In another temperature control device for an injection nozzle according to the present invention, each heating means further includes a heating element in a portion corresponding to the zone and a non-heating element in a portion not corresponding to the zone.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an injection nozzle according to the first embodiment of the present invention, and FIG. 4 is a cross-sectional view of a heating tube according to the first embodiment of the present invention. In the drawing, 10 is an injection nozzle, 22 is a nozzle body, 23 is a nozzle cover which is disposed around the nozzle body 22 and forms an annular space 24, and 25 is a nozzle body 2
2 is a resin flow path formed inside.

Since the injection nozzle 10 having the above-described structure needs to be brought into contact with a mold (not shown) at the time of the injection step, the diameter is formed small so that it can be inserted deeply into the mold. A temperature controller (not shown) is provided so that the molten resin 14 (see FIG. 2) is not easily solidified.
At the same time, the injection nozzle 10 can be heated.

A heating tube 35 is spirally wound in the space 24 around the nozzle body 22. further,
The interior of the space 24 is divided into a zone A on the front end side of the injection nozzle 10 and a zone B on the rear end side of the injection nozzle 10.
The temperature of the injection nozzle 10 is detected by 9 and 30, and the temperatures of the zones A and B can be controlled independently and precisely.

To this end, the heating pipe 35 is provided with a hollow pipe 36, a first heating means 37 provided for controlling the temperature of the zone A, and a heating pipe 35 for controlling the temperature of the zone B. It is formed by the second heating means 38 provided. The first heating means 37 includes a heating element P1 formed at a portion corresponding to the zone A, and a non-heating element P1 formed at a portion corresponding to the zone B for supplying current to the heating element P1. It consists of a heating element P2. In addition, the second
The heating means 38 comprises a heating element portion P3 formed at a portion corresponding to the zone B.

Therefore, different currents are supplied to the heating elements P1 and P3, and the first heating means 37 and the second heating means 38 are operated independently of each other. The temperature can be controlled independently and precisely. Further, since the heating element P1 of the first heating means 37 and the heating element P3 of the second heating means 38 are formed in different zones,
It does not interfere with each other.

Further, since the two coil heaters do not cross on the zone B side, the diameter of the nozzle cover 23 can be reduced, and the size of the injection nozzle 10 can be reduced. And since the temperature of two zones A and B can be controlled by one heating pipe 35, not only can the workability be improved, but also the cost can be reduced.

Next, a second embodiment of the present invention will be described. FIG. 5 is a sectional view of a heating tube according to the second embodiment of the present invention. In addition, about the part which has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol. In this case, the second heating means 48 includes the non-heating element portion P4 formed in the portion corresponding to the zone A and the heating element portion P5 formed in the portion corresponding to the zone B. Will be evenly filled.

Accordingly, the heating element P1 is not biased in the heating tube 35, and it is possible to prevent the occurrence of temperature variation. Next, a third embodiment of the present invention will be described. FIG. 6 is a sectional view of an injection nozzle according to the third embodiment of the present invention. In addition, about the part which has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol.

In this case, the pitch of the winding portion of the heating tube 35 in the zone A is small, and the heating tube 35 in the zone B is small.
The pitch of the winding portion is increased. Therefore, the heating amount in the zone A and the heating amount in the zone B can be further different. It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0024]

As described above in detail, according to the present invention, in a temperature control device for an injection nozzle, in order to control the temperature independently of each other, an injection nozzle having a plurality of zones is set. And a heating tube wound around the injection nozzle. The heating tube includes a plurality of heating means for independently controlling the temperature of each zone, and each heating means includes a heating element at a portion corresponding to the zone.

In this case, by supplying different currents to the respective heating elements and operating the respective heating means independently, the temperatures in the respective zones can be controlled independently and precisely. Further, since the two coil heaters do not cross, the injection nozzle can be downsized.

Since the temperatures of the two zones can be controlled by one heating tube, not only can the workability be improved, but also the cost can be reduced. In another injection nozzle temperature control device of the present invention,
Further, each heating means includes a heating element in a portion corresponding to the zone and a non-heating element in a portion not corresponding to the zone.

In this case, since the heating elements of the respective heating means are formed in different zones, the heating elements do not interfere with each other.

[Brief description of the drawings]

FIG. 1 is a sectional view of an injection nozzle according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a conventional injection device.

FIG. 3 is a sectional view of a conventional injection nozzle.

FIG. 4 is a sectional view of the heating tube according to the first embodiment of the present invention.

FIG. 5 is a sectional view of a heating tube according to a second embodiment of the present invention.

FIG. 6 is a sectional view of an injection nozzle according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Injection nozzle 35 Heating pipe 37 First heating means 38, 48 Second heating means A, B Zones P1, P3, P5 Heating elements P2, P4 Non-heating elements

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 45/72-45/74 B29C 45/20 B29C 45/78 H05B 3/00-3/18

Claims (2)

(57) [Claims] (A) an injection nozzle in which a plurality of zones are set in order to perform temperature control independently of each other;
(B) a heating pipe wound around the injection nozzle; and (c) the heating pipe includes a plurality of heating means for controlling the temperature of each zone independently, and each heating means has a zone. A temperature control device for an injection nozzle, comprising a heating element in a portion corresponding to (1). 2. The injection nozzle temperature control device according to claim 1, wherein each heating means includes a heating element in a portion corresponding to the zone and a non-heating element in a portion not corresponding to the zone.