JP3908672B2 - Hot runner mold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a hot runner mold, and more specifically, a hot runner type having a configuration in which a resin leaking from a sliding portion between a valve stem and a valve bushing or a nozzle or a deteriorated powdery resin is easily accommodated. Regarding molds.
[0002]
[Prior art]
The hot runner mold is a mold that heats the resin, which is the molding material in the material passage to the gate to the cavity, in a fixed mold in order to increase the molding efficiency, and keeps the resin molten in multiple cavities. In order to achieve this, a manifold having a runner as a material passage formed therein is provided in a fixed mold, and this manifold has an electric heater for heating (see Patent Document 1). As such a hot runner type mold 150, as shown in FIG. 5, a cavity plate 130 and a manifold backing plate 140 are fixed to each of a front portion and a rear portion of the manifold plate 110 to which the manifold 120 is assembled. A valve stem 122 is vertically provided in a runner 121 formed on the nozzle 126, and the valve stem 122 is configured to slide on a valve bushing 123. In this type of hot runner mold 150, the sliding portion of the valve bushing 123 and the valve stem 122 is resin-lubricated, so that if this resin flows backward into the cylinder 127, a problem occurs in the push-off of the valve stem 122. . Therefore, conventionally, a drain hole 124 through which the resin leaking from the sliding portion of the valve bushing 123 and the valve stem 122 is discharged to the recessed portion 125 of the manifold plate 110 is penetrated through the valve bushing 123, and the leaked resin or deteriorated powder form The resin was stored in the recessed portion 125 of the manifold plate 110. Although not particularly shown, there is a configuration in which the valve bushing as shown in FIG. 5 is not provided and the valve stem is slid with the nozzle at the front of the manifold. The resin leaking from the moving part or the deteriorated powdery resin is configured to be stored in the recessed portion of the manifold plate.
However, when the resin is accumulated in the recessed portion 125 of the manifold plate 110, the following problem occurs.
(1) The leaked resin or the deteriorated powdery resin (becomes an oligo) may cause leakage or the like by adhering to the sheathed heater terminal and carbonizing.
(2) When the leaked resin or the deteriorated powdery resin enters the recessed portion 125 (which is also an air heat insulating portion) of the manifold plate 110, it becomes easy to cool, and problems such as poor balance and whitening may occur.
(3) Since the leaked resin or deteriorated powdery resin is accumulated in the recessed portion 125 of the manifold plate 110, the hot runner mold 150 is periodically disassembled and assembled to remove the resin. Maintenance was required.
[0003]
[Patent Document 1]
JP-A-9-272137 [0004]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problem, and does not collect resin leaked from a sliding portion between the valve stem and the valve bushing or the nozzle or deteriorated powdery resin in the recessed portion of the manifold plate. An object is to provide a hot runner mold that facilitates disposal.
[0005]
[Means for Solving the Problems]
The inventor has made various studies in order to solve the above-described problems, and has completed the present invention.
That is, according to the present invention, a cavity plate and a manifold backing plate are fixed to each of a front portion and a rear portion of a manifold plate having a recessed portion to which a manifold is assembled, and a valve bushing or a nozzle is provided in a runner formed on the manifold and the nozzle. A hot runner mold in which a valve stem that slides is vertically provided, and a notch formed in communication from the lower end edge of the manifold plate or the lower end edge of the manifold backing plate to the recessed portion, and the notch A drain notch formed by a detachable drain plate for closing the lid is formed, or a drain box whose upper end communicates with the recessed portion is attached to the lower end edge of the manifold plate or the lower end edge of the manifold backing plate. The valve stem The powdery resin obtained by the resin and deterioration that leaks from the sliding portion between the valve bushing or the nozzle, spaced from the recessed portion to a separately provided the drain notch or the drain box in addition to the recessed portion and The gist of the hot runner mold is characterized by being housed.
[0006]
According to the above configuration, the resin leaking from the sliding portion between the valve stem and the valve bushing or the nozzle or the deteriorated powdery resin can be stored in the drain notch or the drain box.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below with reference to the drawings by embodiments. 1 and 2 show the hot runner mold according to the first embodiment, and FIGS. 3 and 4 show the hot runner mold according to the second embodiment.
[0008]
[First Embodiment]
The hot runner mold 50 according to this embodiment is for manufacturing a preform for a PET bottle, and the manifold 20 is assembled to the manifold plate 10 having the recessed portions 25. As shown in FIG. 1, an L-shaped runner 21 is formed in the manifold 20 and the nozzle 26, and a valve stem 22 is provided vertically in the runner 21. The valve stem 22 can freely move back and forth, and its tip end fits into a cavity 31 provided in the cavity plate 30 when moving forward. The rear part of the valve stem 22 slides on the valve bushing 23. The sliding portion between the valve bushing 23 and the valve stem 22 is made of resin lubrication. In order to avoid the problem of push-off of the valve stem 22 caused by this resin flowing back into the cylinder 27, the valve bushing 23 and the valve stem 22 A drain hole 24 through which resin leaking from the sliding portion is discharged to the recessed portion 25 of the manifold plate 10 is provided through the valve bushing 23. Although not shown, the hot runner mold 50 includes a cavity 31, a runner 21, a valve stem 22, a nozzle 26, and a valve bushing 23 in order to simultaneously manufacture a large number of preforms for PET bottles. Many are provided.
[0009]
As shown in FIGS. 1 and 2, a manifold backing plate 40 is fixed to the rear part of the manifold plate 10, and a cavity plate 30 is fixed to the front part of the manifold plate 10. The manifold plate 10 is formed to project downward from the lower ends of the manifold backing plate 40 and the cavity plate 30. The notch 11 is formed in communication with the recessed portion 25 from the lower end edge of the manifold plate 10. Further, the notch 11 is closed with a drain plate 12 having an L-shaped lid. The drain plate 12 is detachably attached to the bottom and sides of the manifold plate 10 with screws 14. As described above, the drain cutout portion 13 includes the cutout 11 and the drain plate 12.
[0010]
In the hot runner mold 50 of the present embodiment configured as described above, the resin discharged from the drain hole 24 falls and accumulates in the drain notch 13, so that the inside of the recessed portion 25 of the manifold plate 10. There is no accumulation in. Further, when a predetermined amount of resin has accumulated in the drain notch 13, the resin accommodated in the drain notch 13 can be easily discarded by removing the screws 14 for fixing the drain plate 12.
[0011]
The hot runner mold 50 of this embodiment in which the drain notch 13 is formed is suitable for a configuration in which the lower end of the manifold plate 10 is below the lower end of the manifold backing plate 40.
[0012]
[Second Embodiment]
Since the runner 21 and the valve stem 22 of the hot runner mold 90 of the present embodiment are the same as those of the first embodiment, overlapping descriptions will be omitted and different points will be described below. In addition, the same code | symbol is used for the component same as 1st Embodiment.
[0013]
As shown in FIG. 3, the manifold backing plate 40 is fixed to the rear part of the manifold plate 10, and the cavity plate 30 is fixed to the front part of the manifold plate 10. The lower end of the manifold plate 10 and the lower end of the manifold backing plate 40 are formed flush with each other. As shown in FIGS. 3 and 4, a drain box 60 is attached to the lower end edge of the manifold plate 10 with screws 61.
[0014]
The manifold plate 10 is formed with a notch 70 whose upper edge communicates with the recessed portion 25 and whose lower edge communicates with the upper edge of the drain box 60.
[0015]
In the hot runner mold 90 of the present embodiment configured as described above, the resin discharged from the drain hole 24 accumulates in the drain box 60 through the notch 70, so that it is in the recessed portion 25 of the manifold plate 10. There is no accumulation. Further, when a predetermined amount of resin is accumulated in the drain box 60, the stored resin can be easily discarded by removing the screw 61 for fixing the drain box 60.
The hot runner mold 90 of the present embodiment provided with the drain box 60 is suitable for a configuration in which the lower end of the manifold plate 10 is flush with or above the lower end of the manifold backing plate 40.
[0017]
The present invention is not limited to the above-described embodiment, and can be embodied by changing various forms.
(1) The drain notch 13 or the drain box 60 may be provided on the manifold backing plate 40.
(2) The hot runner molds 50 and 90 of the present invention are not limited to the manufacture of preforms for PET bottles, and can be applied to the manufacture of various molded products.
(3) In the above embodiment, the hot runner type mold in which the drain hole is formed has been described. However, the resin leaked from the sliding portion of the valve bushing and the valve stem without forming the drain hole, or deteriorated powder It is also possible to use a configuration in which the resin is stored in the recessed portion.
[0018]
【The invention's effect】
Since this invention is comprised as mentioned above, there exist the following effects.
The hot runner mold according to the present invention can store a resin leaked from a sliding portion between a valve stem and a valve bushing or a nozzle or a deteriorated powdery resin in a drain notch or a drain box. For this reason, it is possible to prevent these resins from accumulating in the recessed portions of the manifold plate, so that it is possible to prevent leakage caused by the resin adhering to the sheathed heater terminals and carbonizing, and improving the maintainability of the hot runner mold. Can do.
In addition, since the resin is prevented from entering the recessed portion (air heat insulating portion) in the manifold, problems such as poor balance and whitening are hardly caused, and the yield of molded products can be increased.
In addition, since the resin can be stored in the drain notch or drain box, the resin can be easily discarded, and it is not necessary to disassemble and assemble the hot runner mold to remove the resin, simplifying maintenance. Can be planned.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a lower portion of a hot runner mold according to a first embodiment.
FIG. 2 is a rear view schematically showing a lower part of the hot runner mold according to the first embodiment.
FIG. 3 is a cross-sectional view schematically showing a lower part of a hot runner mold according to a second embodiment.
FIG. 4 is a rear view schematically showing a lower part of a hot runner mold according to a second embodiment.
FIG. 5 is a cross-sectional view schematically showing a lower portion of a conventional hot runner mold.
[Explanation of symbols]
10 Manifold plate 11 Notch 12 Drain plate 13 Drain notch 20 Manifold 21 Runner 22 Valve stem 23 Valve bushing 24 Drain hole 25 Recessed part 26 Nozzle 30 Cavity plate 40 Manifold backing plate 60 Drain box 70 Notch 50, 90 Hot runner Mold

Claims (1)

A cavity plate and a manifold backing plate are fixed to each of a front portion and a rear portion of a manifold plate having a recessed portion to which a manifold is assembled, and a valve stem that slides with a valve bushing or a nozzle in a runner formed on the manifold and the nozzle. A hot runner mold that is vertically installed, and is detachably configured to close a notch formed in communication with the recess from the lower end edge of the manifold plate or the lower end edge of the manifold backing plate A drain notch formed from a drain plate is formed, or a drain box whose upper end communicates with the recessed portion is attached to a lower end edge of the manifold plate or a lower end edge of the manifold backing plate, and the valve stem The valve bush The grayed or resin or degraded powdered resin that leaks from the sliding portion between the nozzle accommodated spaced apart from the recessed portion to separate the drain notch or the drain box is provided in addition to the recess Hot runner mold characterized by that.

Images