JPH10296807A - Injection device for vertical injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate an unstable behavior accompanying the usage of a pellet material without inducing the increase of a cost and without making the device larger even when a pressure air driving part using pressure air is installed, and reduce a defective molding, and improve the molding quality. SOLUTION: The axial directional section of a screw 4 which passes a material feeding port 5o, is made a specified section Xs, and the height of a flight part (specified flight part) 4s in the total section or a partial section of the specified section Xs is formed to be lower than the height of a flight part (normal flight part) 4a at other than the specified section Xs, and thus, a specified gap S is provided between the specified flight part 4s and an internal surface 2i.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection device for a vertical injection molding machine in which a screw is built in a heating cylinder having a vertical axis.

[0002]

2. Description of the Related Art Conventionally, the drive system of an in-line screw type vertical injection molding machine has mainly been an electric drive system,
A hydraulic drive system and an air drive system are known.

[0003] The air drive system is easier to take fire prevention measures and contamination measures than the hydraulic drive system, and is advantageous in terms of weight reduction and cost reduction as compared to both the hydraulic drive system and the electric drive system. Therefore, it is mainly used for small vertical injection molding machines.

In a small vertical injection molding machine, a heating cylinder and a screw are also reduced in size.
The granular pellet material of about m becomes relatively large with respect to the heating cylinder and the screw, and is easily entangled between the opening edge of the material supply port provided on the inner surface of the heating cylinder and the flight part of the screw when the screw moves. As well, the adverse effects of the bite increase. That is, in the injection process, when the screw advances, a reaction force that hinders the advance of the screw acts to make the injection speed unstable, resulting in molding defects such as burrs, short shots, flow marks and the like, and a decrease in molding quality. In addition, in the measuring step, the measuring speed becomes unstable due to the disturbance of the back pressure control, and good plasticization is not performed. Streak problems also occur.

In order to cope with such unstable behavior, the electric drive system and the hydraulic drive system usually have a certain effect by improving control (servo control) and increasing driving force. This leads to an increase in cost and size.

[0006] On the other hand, in the air drive system, unstable behavior tends to be remarkable due to the use of air, and the effect cannot be expected as much as other drive systems depending on the sophistication of control and the response by increasing the driving force. After all, there is no effective countermeasure for unstable behavior in small vertical injection molding machines using the air drive system, and there is a limit to reducing molding defects and improving molding quality. Was.

The present invention has solved the above-mentioned problems in the prior art. In particular, even when a pressure air drive unit using pressure air is mounted, the cost and the size are increased. It is another object of the present invention to provide an injection device for a vertical injection molding machine that can eliminate unstable behavior due to the use of a pellet material, thereby reducing molding defects and improving molding quality.

[0008]

According to the present invention, a screw 4 that is rotated and moved forward and backward by a driving unit 3 is incorporated in a heating cylinder 2 having a longitudinal axis, and the heating cylinder 2 has a vertical axis. When configuring the injection device 1 of the vertical injection molding machine M having the material supply unit 5 for supplying the pellet material P from the material supply port 5o provided on the inner surface 2i, the axial direction of the screw 4 passing through the material supply port 5o Section to specific section X
s, and the height of the flight section (specific flight section) 4s in the entire section or a partial section of the specific section Xs is changed to the flight section (regular flight section) other than the specific section Xs.
By forming it lower than the height of 4a, a predetermined gap S is provided between the specific flight portion 4s and the inner surface 2i.

In this case, according to a preferred embodiment, the driving unit 3 uses a pressure air driving unit 3o using pressure air.
Further, the specific section Xs includes a section facing the material supply port 5o when the screw 4 moves at least from the last retreat position to the most forward position. On the other hand, the height of the specific flight portion 4s is selected such that the gap S is larger than the dimensions of the pellet materials P. Specifically, the height of the specific flight section 4s can be set to zero. At this time, a plurality of peaks 11... Or valleys 12 parallel to the axial direction are provided on the outer peripheral surface of the screw 4.
... can also be provided. Further, the specific flight section 4s is formed at a predetermined height, and at this time, the height Hs in the entire section or a partial section of the specific section Xs can be increased as going forward in the forward / backward direction Df.

[0010] Thereby, the heating cylinder 2 is connected to the material supply port 5o.
Supplied into the inside of the heating cylinder 2 can fall through the gap S in the heating cylinder 2. That is, in the horizontal injection molding machine, since the heating cylinder is arranged in the horizontal direction, the pellet material supplied from the material supply port is transferred in the horizontal direction by the screw.
Since the heating cylinder 2 has a vertical axis, the material supply port 5
The pellet material P supplied from o is reliably supplied to the regular flight section 4a by dropping in the specific section Xs. At this time, if the gap S in the specific section Xs is made larger than the dimension of the pellet material P, the pellet material P bites between the opening edge of the material supply port 5o and the specific flight portion 4s when the screw 4 moves. Adverse effects are reliably avoided and no unstable behavior occurs during injection and metering. Therefore, even when the pressure air drive unit 3o using the pressure air is mounted, the control is advanced (servo control).
The unstable behavior associated with the use of the pellet material is eliminated without increasing the driving force. In addition, specific flight section 4
If the height of s is set to zero, or the specific flight section 4s is formed at a predetermined height, and the height Hs in the entire section or a partial section of the specific section Xs is increased toward the forward and backward direction Df, Unstable behavior can be avoided more reliably and good plasticization is realized. A plurality of peaks 11... Or valleys 12 parallel to the axial direction are provided on the outer peripheral surface of the screw 4.
Are provided, the strength of the screw 4 can be increased.

[0011]

Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, an injection apparatus 1 according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 6 shows an example of a vertical injection molding machine M provided with the injection device 1. The vertical injection molding machine M includes an injection device 1 on a machine base 20, and further includes the heating cylinder 2 having a vertical axis in the injection device 1. And this heating cylinder 2
The screw 4 (FIG. 1) is built in the inside. Further, a pressure air driving unit 3o (driving unit 3) including an air cylinder or the like driven by pressure air supplied from the pressure air supply source 21 is provided, and the screw 4 is rotated and moved forward and backward by the pressure air driving unit 3o. On the other hand, a material supply port 5o as shown in FIG. 1 is opened on the inner surface of the heating cylinder 2, and pellet materials P are supplied from the material supply section 5. The material supply section 5 has a hopper 22 for accommodating pellet materials P... And a material supply path 23 extending from the bottom of the hopper 22 to the inside of the heating cylinder 2. The material supply path 23 is inclined and faces obliquely upward from the inside of the heating cylinder 2 as shown in FIG. The vertical injection molding machine M shown in FIG. 6 is a front surface, and the material supply unit 5 drawn on the side surface by a virtual line is usually arranged on the rear side of the vertical injection molding machine M (the injection device 1). You. Others
In FIG. 6, reference numeral 24 denotes a mold clamping device, 25 denotes a mold, 26 denotes a control panel, and 27 denotes an injection nozzle provided at the tip of the heating cylinder 2.

The screw 4 is constructed in accordance with the present invention. That is, as shown in FIG. 1, the axial section of the screw 4 passing through the material supply port 5o is defined as a specific section Xs, and the flight section (specific flight section) 4s in the specific section Xs is provided.
Is formed lower than the height of the flight section (regular flight section) 4a other than the specific section Xs. In the first embodiment, in particular, by setting the height of the specific flight section 4s to zero, the specific flight section 4s and the inner surface 2i of the heating cylinder 2 are set.
A gap S larger than the dimensions of the pellet materials P was provided between them.

In this case, the screw 4 is located in the specific section Xs.
Includes a section facing the material supply port 5o when at least moves from the last retracted position to the most advanced position. Therefore, this does not prevent the case where all the specific flight portions 4s located behind the material supply port 5o in the forward and backward directions are set to zero. In addition, as shown in FIG.
A plurality of peaks 11 and valleys 12 parallel to the axial direction can be provided. Thereby, the strength of the screw 4 in the specific section Xs can be increased. Further, FIGS. 4 and 5 show a modified example in which peaks 11... And valleys 12. In this modified example, since the peaks 11 contact the inner surface 2i of the heating cylinder 2, the pellet materials P supplied from the material supply port 5o are distributed over the entire circumference of the screw 4 so that the inner surface 2i of the heating cylinder 2 can be spread. Then, a ring-shaped concave passage 2r communicating with the material supply port 5o was formed.

According to the injection apparatus 1 according to the first embodiment, as shown in FIG. 1, the pellet materials P are supplied through the material supply path 23 in the direction of the arrow Ds, and the material supply port 5o is provided.
From the heating cylinder 2. The pellet material P supplied to the inside of the heating cylinder 2 falls through the gap S in the heating cylinder 2 and is supplied to the regular flight section 4a existing in the forward / backward direction of the specific section Xs. At this time, the gap S in the specific section Xs is larger than the size of the pellet material P.
Pellet material P ...
The harmful effects of erosion are reliably avoided, and no unstable behavior occurs during injection and metering.

Next, an injection apparatus 1 according to a second embodiment of the present invention will be described with reference to FIGS.

In the second embodiment, the specific flight section 4s in the specific section Xs is formed at a predetermined height Hs. In this case, the height Hs of the specific flight portion 4s is selected, and a gap S larger than the size of the pellet material P is provided between the specific flight portion 4s and the inner surface 2i of the heating cylinder 2. Further, all heights of the specific flight section 4s in the specific section Xs may be fixed, but as shown in FIG.
It may be gradually increased as going to f. When such a form is not adopted, a part of the regular flight part 4a and a part of the specific flight part 4s are mixed at the end of the specific section Xs as shown in FIG.

Therefore, even in the configuration of the second embodiment, a gap S larger than the size of the pellet material P is provided between the specific flight section 4s and the inner surface 2i of the heating cylinder 2 in the specific section Xs. The same operation and effect as those of the first embodiment are obtained. In FIGS. 7 to 9 showing the second embodiment,
The same components as those in FIGS. 1 to 6 showing the first embodiment are denoted by the same reference numerals to clarify the configuration, and detailed description is omitted.

Although the embodiments have been described in detail above, the present invention is not limited to such embodiments, and any configuration, shape, quantity, material, etc. of the details may be used without departing from the gist of the present invention. Can be changed to

For example, the case where the present invention is applied to the air drive system has been described, but the present invention is not necessarily limited to the air drive system and does not prevent the case where the present invention is applied to the electric drive system and the hydraulic drive system. It is desirable that the height of the specific flight portion 4s is selected so that the gap S is larger than the dimension of the pellet material P. However, in the case where the gap S is slightly smaller than the dimension of the pellet material P. However, a form in which a certain effect can be obtained is included in the gist of the present invention. Further, the section in which the specific flight section 4s is provided may be the entire section of the specific section Xs as in the embodiment, or may be a partial section. Even when applied to such a partial section, a certain effect can be expected.

[0022]

As described above, in the injection device of the vertical injection molding machine according to the present invention, the axial section of the screw passing through the material supply port is set as the specific section, and the entire section or a partial section of the specific section is used. By forming the height of the specific flight section lower than the height of the regular flight section other than the specific section, a predetermined gap is provided between the specific flight section and the inner surface of the heating cylinder. Play.

[0023] Unstable behavior due to the use of pellet material can be eliminated without performing advanced control (servo control) or increasing driving force, thereby reducing molding defects and improving molding quality. Therefore, an increase in cost and an increase in size are avoided, and it is particularly suitable for a vertical injection molding machine equipped with a pressure air drive unit using pressure air.

According to a preferred embodiment, the height of the specific flight section is set to zero, or the specific flight section is formed at a predetermined height, and the height of the entire section or a partial section of the specific section is set in the forward / backward direction. If the height is increased in the forward direction, the unstable behavior can be more reliably avoided and good plasticization can be realized.

According to a preferred embodiment, the strength of the screw can be increased by providing a plurality of peaks or valleys parallel to the axial direction on the outer peripheral surface of the screw.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a screw provided in an injection device of a vertical injection molding machine according to a first embodiment of the present invention,

FIG. 2 is a sectional view taken along the line AA in FIG. 1 according to the embodiment;

FIG. 3 is a sectional view taken along line AA in FIG. 1 according to another embodiment of the embodiment;

FIG. 4 is a configuration diagram of a screw according to a modified example provided in the injection device of the embodiment;

FIG. 5 is a sectional view taken along line BB in FIG. 4 according to the modification;

FIG. 6 is a front view of a vertical injection molding machine including the injection device according to the present invention,

FIG. 7 is a configuration diagram of a screw provided in an injection device of a vertical injection molding machine according to a second embodiment of the present invention;

FIG. 8 is an enlarged sectional view showing a part of the screw according to the embodiment;

FIG. 9 is an enlarged sectional view showing a part of a screw according to another embodiment of the embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection device 2 Heating cylinder 2i Inner surface of heating cylinder 3 Drive part 3o Pressure air drive part 4 Screw 4s Specific flight part 4a Regular flight part 5 Material supply part 5o Material supply port 11 ... Mountain part 12 ... Valley part P ... Pellet material M Vertical injection molding machine Xs Specific section S Predetermined gap Hs Height of specific flight section Df Forward and backward directions

Claims (7)

[Claims] 1. Inside a heating cylinder having a longitudinal axis,
An injection device for a vertical injection molding machine, which incorporates a screw that rotates and moves forward and backward by a driving unit, and further includes a material supply unit that supplies a pellet material from a material supply port provided on an inner surface of the heating cylinder. The axial section of the screw passing through the specific section is defined as a specific section, and the height of the flight section (specific flight section) in the entire section or a partial section of the specific section is set to the height of the flight section (regular flight section) other than the specific section. By forming lower than
An injection device for a vertical injection molding machine, wherein a predetermined gap is provided between the specific flight section and an inner surface of the heating cylinder. 2. The injection device for a vertical injection molding machine according to claim 1, wherein said driving section is a pressure air driving section using pressure air. 3. The vertical injection molding according to claim 1, wherein the specific section includes a section facing the material supply port when the screw has moved at least from a last retracted position to a most advanced position. Machine injection equipment. 4. The injection device for a vertical injection molding machine according to claim 1, wherein the height of the specific flight portion is selected so that the gap is larger than the size of the pellet material. 5. The injection device for a vertical injection molding machine according to claim 1, wherein the height of the specific flight section is set to zero. 6. The vertical type according to claim 5, wherein the specific flight portion has a height of zero, and a plurality of peaks or valleys parallel to the axial direction are provided on an outer peripheral surface of the screw. Injection equipment for injection molding machines. 7. The specific flight section is formed at a predetermined height, and the height of the entire section or a partial section of the specific section is increased toward the front in the retreating direction. An injection device of the vertical injection molding machine as described in the above.