JP2003320551A - Injection nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently prevent stringing, drooling or the like and to improve the durability of an injection nozzle. <P>SOLUTION: The injection nozzle has a tubular main body 50 and a nozzle heater heating a resin in a resin passage 50a. A heat insulating slit part 60 provided with grooves 61-63 is formed in the front end part of the main body 50. The slit part 60 is provided also with thread parts p1-p3 at prescribed places and thin-wall parts q1-q3 are formed between the thread parts p1-p3. Since the distance from the inner peripheral surface of the resin passage 50a to the outer peripheral surface of the root portion 65 is long at the thread parts p1-p3, a tensile strength can be enlarged. Since the distance from the inner peripheral surface of the resin passage 50a to the outer peripheral surface of the root portion 65 is short at the thin-wall parts q1-q3, the cooling effect of the resin in the resin passage 50a can be enhanced. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an injection nozzle.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, a resin heated and melted in a heating cylinder is injected at a high pressure to fill a cavity space of a mold device.
A molded product can be obtained by cooling and solidifying in the cavity space.

Therefore, the injection molding machine is equipped with a mold clamping device,
A mold device and an injection device, the mold clamping device includes a fixed platen and a movable platen, and the mold device includes a fixed mold attached to the fixed platen and a movable mold attached to the movable platen. A mold is provided and the mold clamping cylinder of the mold clamping device advances and retracts the movable platen to perform mold closing, mold clamping and mold opening of the mold device.

On the other hand, the injection device includes a heating cylinder for heating and melting the resin supplied from the hopper, and an injection nozzle for injecting the melted resin, and a screw is freely rotatable in the heating cylinder. And is arranged so that it can move back and forth. Then, the resin is injected from the injection nozzle by advancing the screw, and the resin is measured by rotating the screw.

By the way, the injection nozzle is retracted in the measuring process and separated from the fixed mold. At this time, if the temperature of the resin is high, stringing and nose at the front end of the injection nozzle are caused. Who will occur.

Therefore, at a predetermined position of the injection nozzle,
A heat insulating slit portion is formed to prevent heat from being transmitted from the rear to the front.

FIG. 2 is a vertical sectional view of a conventional injection nozzle, and FIG.
FIG. 6 is a cross-sectional view of a conventional injection nozzle.

In the figure, reference numeral 11 denotes a cylindrical injection nozzle. The injection nozzle 11 includes a cylindrical main body 50 and a nozzle heater 13 arranged around the main body 50. A resin flow channel 50a is formed in the nozzle, and the resin flow channel 50a is opened at a nozzle port 51 formed at the front end (left end in FIG. 2). Then, by energizing the nozzle heater 13, the resin in the resin flow path 50a is heated.

The injection nozzle 11 is attached to the front end of a heating cylinder (not shown) so that the resin flow passage in the heating cylinder and the resin flow passage 50a are communicated with each other. Then, in the injection step, the injection nozzle 11 is moved forward (moved to the left in FIG. 2), pressed against the fixed mold 15 of the mold device, and the resin melted in the heating cylinder is injected into the injection nozzle 11. And is injected into the cavity space of the mold device through the sprue 16 in the fixed mold 15.

By the way, at the front end portion (left end portion in FIG. 2) of the resin flow path 50a, the taper portion is formed by gradually decreasing the inner diameter from the rear side (right side in FIG. 2) to the front side (left side in FIG. 2). 19 is formed, and the nozzle opening 5 is formed in front of the tapered portion 19.
The reverse taper portion 20 is formed by gradually increasing the inner diameter toward 1. Therefore, the resin in the sprue 16 and the reverse taper portion 20 are cooled as the mold device is cooled.
The resin inside is solidified together with the molded product to form a sprue portion (not shown) made of a resin piece. on the other hand,
At the cutting portion S1 between the taper portion 19 and the reverse taper portion 20, the resin flow path 50a has the smallest inner diameter, so that the resin in the taper portion 19 and the resin in the reverse taper portion 20 are easily separated.

Therefore, when the sprue portion is taken out together with the molded product as the mold is opened, the taper portion 1
9 and the reverse taper portion 20 are cut off.

Then, in the measuring step, when the injection nozzle 11 is retracted (moved to the right in FIG. 2) and separated from the fixed mold 15, stringing and nose at the front end of the injection nozzle 11 are performed. In order to prevent the occurrence of drooping, the cutting portion S at the front end of the main body 50
A heat insulating slit portion 55 for preventing heat from being transmitted from the rear to the front is formed at the position 1. The heat insulating slit portion 55 is provided with an annular groove having a predetermined depth from the outer peripheral surface of the main body 50 toward the inner side in the radial direction.

[0013]

However, in the conventional injection nozzle 11 described above, when it is necessary to use a resin having a low viscosity in a molten state or to increase the diameter of the nozzle port 51. Is a string puller,
It is not possible to sufficiently prevent nasal discharge and the like.

Therefore, it is conceivable to make the groove of the heat insulating slit portion 55 deep in order to enhance the cooling effect of the resin by the heat insulating slit portion 55. However, if the groove is made deep, the injection nozzle 11 is fixed to the fixed mold 15. When the nozzle touch is performed by abutting, the eccentric force is applied to the injection nozzle 11 by the reaction force from the fixed mold 15, and the eccentric force is a portion radially inward of the heat insulating slit portion 55, that is, a root portion. Since it acts as a bending force, the durability of the injection nozzle 11 is reduced.

The present invention solves the problems of the conventional injection nozzle, can sufficiently prevent the occurrence of stringing, nasal discharge, etc., and can improve the durability of the injection nozzle. It is intended to provide a nozzle.

[0016]

To this end, in the injection nozzle of the present invention, it is arranged at the front end of the heating cylinder,
It has a cylindrical main body having a resin flow path opened at the front end, and a nozzle heater that is arranged around the main body and heats the resin in the resin flow path.

A heat insulating slit portion having a groove formed radially inward from the outer peripheral surface of the main body is formed at the front end portion of the main body.

Further, the heat insulating slit portion is provided with a protruding portion at a predetermined position in the circumferential direction of the main body, and a thin wall portion is formed between the protruding portions so as to be close to the resin flow path.

In another injection nozzle of the present invention, the groove is further formed at a plurality of positions in the circumferential direction of the main body.

In still another injection nozzle of the present invention,
Further, the protruding portion is formed so as to reach the outer peripheral surface of the main body.

In still another injection nozzle of the present invention,
Further, the protruding portion is formed so as to reach near the outer peripheral surface of the main body.

In still another injection nozzle of the present invention,
Further, an odd number of the protrusions are formed.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described 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, FIG. 4 is a cross-sectional view of an essential part of an injection device according to the first embodiment of the present invention, and FIG. 5 is a view of the present invention. First
3 is a vertical cross-sectional view of the injection nozzle according to the embodiment of FIG.

In FIG. 4, reference numeral 12 is a heating cylinder as a cylinder portion, and the front end of the heating cylinder 12 (see FIG.
A cylindrical injection nozzle 11 is attached to the left end of the figure, and a nozzle heater 13 as a heating member is arranged around the injection nozzle 11. Inside the heating cylinder 12, a screw 22 as an injection member is rotatably and movably arranged. The heating cylinder 1
Both 2 and the injection nozzle 11 are formed of a metal material.

The screw 22 has a screw head 25 at the front end, extends rearward (rightward in FIG. 4) in the heating cylinder 12, and has a rear end (rightward in FIG. 4) at the first end (not shown). Is connected to a metering motor as a drive unit of the above and an injection motor as a second drive unit. Further, a spiral flight 23 is formed around the screw 22, and a groove 26 is formed along the flight 23.

A resin supply port 29 is formed at a predetermined position of the heating cylinder 12, and a hopper 30 is attached to the resin supply port 29. The resin supply port 29 is
The screw 22 is formed at a position corresponding to the rear end portion (the right end portion in FIG. 4) of the groove 26 in a state where the screw 22 is placed at the most forward position (left side in FIG. 4) in the heating cylinder 12.

In the measuring step, when the screw 22 is rotated by driving the measuring motor, the pellet-shaped resin 33 in the hopper 30 drops and enters the heating cylinder 12, and the groove 26 Is moved forward (moved to the left in FIG. 4). Along with that, the screw 22 is retracted (moved to the right in FIG. 4).

Further, around the heating cylinder 12,
A cylinder heater (not shown) is provided, the heating cylinder 12 is heated by the cylinder heater, and the resin in the heating cylinder 12 can be melted. Therefore, the screw 22 is retracted by a predetermined amount by the resin pressure generated by rotating the screw 22, and the screw head 25
The molten resin for one shot is stored in front of.

Subsequently, in the injection step, when the screw 22 is moved forward by driving the injection motor, the resin stored in front of the screw head 25 is injected from the injection nozzle 11 and is not shown. The cavity space of the mold device is filled.

Next, the injection nozzle 11 will be described.

In FIG. 5, 11 is an injection nozzle,
The injection nozzle 11 includes a cylindrical main body 50, and the main body 50.
Is provided with a nozzle heater 13 and a resin flow channel 50a is formed in the main body 50.
a is a nozzle port 5 formed at the front end (left end in FIG. 5)
Opened at 1. And the heater 1 for the nozzle
By energizing 3, the resin in the resin channel 50a is heated and the molten state is maintained. In addition, a temperature sensor (not shown) is embedded in the main body 50, the temperature of the resin is detected by the temperature sensor, and the energization of the nozzle heater 13 is controlled based on the detected temperature.

The injection nozzle 11 includes a heating cylinder 12
It is attached to the front end of (FIG. 4), and the resin flow path in the heating cylinder 12 and the resin flow path 50a are communicated with each other.
Then, in the injection step, the injection nozzle 11 is moved forward (moved to the left in FIG. 5) and pressed against the fixed mold 15 of the mold device, and drives the injection motor as described above. By the screw 2
When 2 is moved forward, the resin accumulated in front of the screw 22 is injected from the injection nozzle 11, and the fixed mold 15
The cavity space is filled through the inner sprue 16.

After that, when the mold device is cooled, the resin filled in the cavity space is cooled to form a molded product, and the mold device is opened to take out the molded product.

The front end portion of the resin flow path 50a (see FIG. 5)
At the left end portion thereof, a tapered portion 19 is formed by gradually decreasing the inner diameter from the rear (right side in FIG. 5) to the front (left side in FIG. 5).
In front of the taper portion 19, the reverse taper portion 20 is formed by gradually increasing the inner diameter toward the nozzle port 51.
Is formed. Therefore, as the mold device cools,
The resin 33 in the sprue 16 and the resin 33 in the reverse taper portion 20 are integrally solidified with the molded product to form a sprue portion (not shown) made of a resin piece. On the other hand, in the cutting portion S1 between the tapered portion 19 and the reverse tapered portion 20,
Since the inner diameter of the resin flow path 50a is the smallest, the resin 33 in the taper portion 19 and the resin 33 in the reverse taper portion 20 are easily separated.

Therefore, when the sprue portion is taken out together with the molded product, the gap between the taper portion 19 and the reverse taper portion 20 is cut. The inner diameter of the sprue portion becomes smaller as it gets closer to the cutting portion S1, and the sprue portion has a shape that can be easily taken out from the mold device and the injection nozzle 11.

By the way, in the measuring step, the injection nozzle 11 is moved backward (moved to the right in FIG. 5) and separated from the fixed mold 15. At this time, the resin 33 in front of the cutting portion S1 is removed. When the temperature is high, stringing, dripping, etc. occur at the front end of the injection nozzle 11. Therefore, in the injection nozzle 11 formed of a metal material having a high thermal conductivity, in order to prevent heat from being transferred from the rear to the front, a predetermined position in the axial direction of the front end portion of the main body 50, for example, A heat insulating slit portion 60 is formed at the position of the cutting portion S1 as a heat conduction preventing means.
As shown in FIG. 1, the heat insulating slit portion 60 is formed from the outer peripheral surface of the main body 50 inward in the radial direction and has a plurality of grooves 61 to 63 having flat bottoms.

In this embodiment, each of the grooves 61 to 63 is
Has three arcuate shapes formed at equal pitch angles in the circumferential direction of the main body 50. Therefore, the main body 5
At 0, the shape of the cross section of the root portion 65 as a heat shield is triangular. The root portion 65 is provided with ridges p1 to p3 extending to the outer peripheral surface of the main body 50 at a plurality of points in the circumferential direction of the main body 50, in the present embodiment, at three points. Thin portions q1 to q3 are formed between the ridges p1 to p3 in close proximity to the resin flow path 50a.

In the ridges p1 to p3, since the distance from the inner peripheral surface of the resin flow path 50a to the outer peripheral surface of the root portion 65 is long, the tensile strength can be increased. Further, in the thin portions q1 to q3, the resin flow channel 50a
Since the distance from the inner peripheral surface to the outer peripheral surface of the root portion 65 is short, the effect of cooling the resin in the resin flow channel 50a can be enhanced. Further, the grooves 61 to 63 are deepened to increase the tensile strength of the protrusions p1 to p3, and the distance from the inner peripheral surface of the resin flow channel 50a to the outer peripheral surface of the root portion 65 is shortened. As a result, the effect of cooling the resin in the resin flow channel 50a can be further enhanced.

Since it is possible to enhance the cooling effect of the resin in the thin portions q1 to q3, it is necessary to use a resin having a low viscosity in the molten state or to increase the diameter of the nozzle port 51. Even in the case of dripping, it is possible to sufficiently prevent the occurrence of stringing, dripping, etc.

Further, when the injection nozzle 11 is brought into contact with the fixed mold 15 and a nozzle touch is performed, if an eccentric force is applied to the injection nozzle 11 by the reaction force from the fixed mold 15, the eccentric force is The tensile force acts on the portion 65 as a bending force, and a tensile force is generated at a point 180 [°] away from the point at which the bending force acts, but since the strength of the protrusions p1 to p3 is increased, Even if a force and a bending stress accompanied therewith act on the protrusions p1 to p3, the injection nozzle 11 is not deformed, and the durability of the injection nozzle 11 can be improved.

In the present embodiment, the main body 50
A plurality of grooves 61 to 63 are formed in each of the ridges p1 to p3
Although it is formed so as to reach the outer peripheral surface of the main body 50, it can be formed so as to reach the vicinity of the outer peripheral surface of the main body 50. In that case, one annular groove is formed in the main body 50 and communicates with each other.

In the present embodiment, all of the tops of the protrusions p1 to p3 are placed on the outer peripheral surface of the main body 50, but the tops are placed slightly inside the outer peripheral surface. You can also

By the way, when a bending force is applied to the root portion 65, the maximum compressive force is applied at a predetermined point in the circumferential direction of the root portion 65, and 180 degrees from the point.
The maximum tensile force is applied at points [°] apart.

For example, when the maximum compressive force is applied to the point where the ridges p1 to p3 are formed, 1 from the point where the compressive force acts.
The maximum tensile force is about to be applied at a point 80 [°] apart, but since the compressive force is received by the protruding portions p1 to p3, the tensile force does not act at the point 180 [°] apart.
Further, when the maximum compressive force is applied to the point separated by 180 °, the maximum tensile force acts on the ridges p1 to p3, but the ridges p1 to p3 extend to the outer peripheral surface of the main body 50. Since it is formed to extend, it can withstand the tensile force. Therefore, the root portion 65 is not damaged.

From this, the thin-walled portions q1 to q are formed at points 180 [°] away from the points where the protrusions p1 to p3 are formed.
3 to form the protrusions p1 to p3 and the thin portion q1.
It is preferable to form an odd number of ~ q3.

Next, a second embodiment of the present invention will be described.

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

In the figure, 50 is a main body, and the main body 5
A heat insulating slit portion 60 as a heat conduction preventing means is formed at a predetermined position in the axial direction of the front end portion of 0, for example, a position of the cut portion S1 (FIG. 5). The heat insulating slit portion 60 is
A plurality of grooves 61 to 63, which are formed from the outer peripheral surface of the main body 50 toward the inner side in the radial direction and whose bottoms are curved in a concave shape, are provided.

In the present embodiment, each groove 61-63.
Has three substantially elliptical shapes formed at equal pitch angles in the circumferential direction of the main body 50. Therefore, in the main body 50, the root portion 65 as a heat shield portion is provided.
The cross-sectional shape of is made substantially triangular. Then, the root portion 65 has three protrusions p1 to p1 extending to the outer peripheral surface of the main body 50 in three circumferential regions of the main body 50.
3, each ridge p1 in the circumferential direction of the main body 50
Between the p3, the thin wall portions q1 to q are brought close to the resin flow channel 50a.
3 is formed.

Next, a third embodiment of the present invention will be described.

FIG. 7 is a cross-sectional view of an injection nozzle according to the third embodiment of the present invention.

In the figure, 50 is a main body, and the main body 5
A heat insulating slit portion 60 as a heat conduction preventing means is formed at a predetermined position in the axial direction of the front end portion of 0, for example, a position of the cut portion S1 (FIG. 5). The heat insulating slit portion 60 is
A plurality of grooves 71 to 74 formed radially inward from the outer peripheral surface of the main body 50 are provided.

In the present embodiment, each groove 71-74
Has four substantially triangular shapes formed at equal pitch angles in the circumferential direction of the main body 50. Therefore,
In the main body 50, the shape of the cross section of the root portion 65 as the heat shield portion is substantially a cross shape. Then, the root portion 65 has four ridge portions p11 to the outer peripheral surface of the main body 50 in four regions in the circumferential direction of the main body 50.
p14, each ridge p in the circumferential direction of the main body 50
Thin portions q11 to q14 are formed between 11 to p14 so as to be close to the resin flow path 50a.

Next, a fourth embodiment of the present invention will be described.

FIG. 8 is a cross sectional view of an injection nozzle according to the fourth embodiment of the present invention.

In the figure, 50 is a main body, and the main body 5
A heat insulating slit portion 60 as a heat conduction preventing means is formed at a predetermined position in the axial direction of the front end portion of 0, for example, a position of the cut portion S1 (FIG. 5). The heat insulating slit portion 60 is
The main body 50 includes a plurality of grooves 81 to 85 formed radially inward from the outer peripheral surface thereof.

In this embodiment, each groove 81 to 85 is formed.
Has five substantially triangular shapes formed at equal pitch angles in the circumferential direction of the main body 50. Then, the root portion 65 has a ridge portion p21 extending to the outer peripheral surface of the main body 50 in five regions in the circumferential direction of the main body 50.
To p25, thin portions q21 to q25 are formed between the projecting streaks p21 to p25 in the circumferential direction of the main body 50 in close proximity to the resin flow path 50a.

Next explained is the fifth embodiment of the invention.

FIG. 9 is a cross sectional view of an injection nozzle according to the fifth embodiment of the present invention.

In the figure, 50 is a main body, and the main body 5
A heat insulating slit portion 60 as a heat conduction preventing means is formed at a predetermined position in the axial direction of the front end portion of 0, for example, a position of the cut portion S1 (FIG. 5). The heat insulating slit portion 60 is
The main body 50 is provided with a plurality of grooves 91 to 94 formed radially inward from the outer peripheral surface and having a convexly curved bottom.

In the present embodiment, each groove 91-94.
Has four substantially fan-shaped shapes formed at equal pitch angles in the circumferential direction of the main body 50. Then, the root portion 65 has four protrusions p31 to p31 extending to the outer peripheral surface of the main body 50 in four regions in the circumferential direction of the main body 50.
p34 and each ridge p in the circumferential direction of the main body 50
Thin portions q31 to q34 are formed between 31 to p34 in proximity to the resin flow channel 50a.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0064]

As described above in detail, according to the present invention, in the injection nozzle, the cylindrical main body is provided at the front end of the heating cylinder, and has the resin flow path opened at the front end. The nozzle heater is provided around the main body and heats the resin in the resin flow path.

A heat insulating slit portion having a groove formed radially inward from the outer peripheral surface of the main body is formed at the front end of the main body.

Further, the heat insulating slit portion is provided with a protruding portion at a predetermined position in the circumferential direction of the main body, and a thin portion is formed between the protruding portions so as to be close to the resin flow path.

In this case, since the distance from the inner peripheral surface of the resin flow path to the outer peripheral surface of the root portion is long in the protruding portion, the tensile strength can be increased. Further, in the thin portion, since the distance from the inner peripheral surface of the resin flow path to the outer peripheral surface of the root portion is short, the effect of cooling the resin in the resin flow path can be enhanced.

Since it is possible to enhance the cooling effect of the resin in the thin portion, even when it is necessary to use a resin having a low viscosity in a molten state or to increase the diameter of the nozzle port. It is possible to sufficiently prevent stringing, dripping and the like from occurring.

Further, when an eccentric force is applied to the injection nozzle by a reaction force from the mold device when the injection nozzle is brought into contact with the mold device and a nozzle touch is performed, the eccentric force bends at the root portion. The tensile force is generated at a point 180 [°] away from the point where the bending force acts, but since the tensile strength of the ridge portion is increased, the tensile force and the bending stress accompanying it are generated. Even if the above acts on the protrusion, the injection nozzle is not deformed, and the durability of the injection nozzle can be improved.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view of a conventional injection nozzle.

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

FIG. 4 is a cross-sectional view of main parts of the injection device according to the first embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of an injection nozzle according to the first embodiment of the present invention.

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

FIG. 7 is a transverse sectional view of an injection nozzle according to a third embodiment of the present invention.

FIG. 8 is a transverse sectional view of an injection nozzle according to a fourth embodiment of the present invention.

FIG. 9 is a cross-sectional view of an injection nozzle according to a fifth embodiment of the present invention.

[Explanation of symbols]

11 Injection Nozzle 12 Heating Cylinder 13 Nozzle Heater 33 Resin 50 Main Body 50a Resin Flow Path 60 Adiabatic Slits 61-63, 71-74, 81-85, 91-94
Grooves p1 to p3, p11 to p14, p21 to p25, p31
To p34 ridges q1 to q3, q11 to q14, q21 to q25, q31
~ Q34 Thin part

Claims (5)

[Claims] 1. (a) disposed at the front end of the heating cylinder,
A cylindrical main body having a resin flow path opened at the front end, and (b) a nozzle heater that is arranged around the main body and heats the resin in the resin flow path,
(C) A heat insulating slit portion having a groove formed radially inward from an outer peripheral surface of the main body is formed at a front end portion of the main body, and (d) the heat insulating slit portion is formed in a circumferential direction of the main body. A ridge portion at a predetermined position in, between the ridge portions,
An injection nozzle characterized in that a thin portion is formed close to the resin flow path. 2. The injection nozzle according to claim 1, wherein the groove is formed at a plurality of positions in a circumferential direction of the main body. 3. The injection nozzle according to claim 1, wherein the protrusion is formed so as to reach the outer peripheral surface of the main body. 4. The injection nozzle according to claim 1, wherein the protruding portion is formed so as to reach near the outer peripheral surface of the main body. 5. The injection nozzle according to claim 1, wherein an odd number of the protrusions are formed.