JP2020157599A - Injection molding machine - Google Patents

Abstract

To provide an injection molding machine capable of smoothly feeding a molding material to an injection device by preventing the molding materials in a hopper from adhering.SOLUTION: Heat-insulating means is interposed between a hopper 11 and an injection device 20 in an injection molding machine 1 provided with a feeding device 10 including the hopper 11 to be charged with a molding material (pellet resin) 2 from a charging port 11a, and the injection device 20 for injecting a molding material 2 from an injection opening (injection nozzle) 23 to a metal mold 30 while melting the molding material 2 fed from a discharging port 11b of the hopper 11 of the feeding device 10. The heat-insulating means is constituted by a heat-insulating material 50, an air layer 51, or a vacuum layer 52. Cooling means is interposed between the hopper 11 and the injection device 20. The cooling means is constituted by a cooling path 60 for flowing a cooling medium. In this case, the cooling medium may be air or water.SELECTED DRAWING: Figure 2

Description

The present invention relates to an injection molding machine including a supply device for supplying a molding material to be charged into a hopper to an injection device.

An injection molding machine for manufacturing a resin product or the like by injection molding includes a supply device including a hopper in which a molding material such as pellet resin is charged from an injection port, and molding supplied from the discharge port of the hopper of the supply device. It is equipped with an injection device that injects the material from the injection port into the mold while melting it. Here, a conventional example of such an injection molding machine is shown in FIG.

That is, FIG. 8 is a vertical cross-sectional view of the hopper portion of the conventional injection molding machine. As shown in the drawing, the hopper 111 is configured as a substantially cylindrical tank, and the molding material 102 is charged on the upper surface thereof. The circular hole-shaped input port 111a is open. Further, the inner wall of the lower end portion of the hopper 111 is formed in a shape narrowed downward, and a circular hole-shaped discharge port 111b penetrating in the vertical direction is formed in the center thereof. A heating cylinder 121 of the injection device 120 is arranged below the hopper 111, and a screw 122 is rotatably inserted into the heating cylinder 121. A circular hole-shaped supply port 121a is formed in the heating cylinder 121, and the supply port 121a communicates with the discharge port 111b that opens at the bottom of the hopper 111. The heating cylinder 121 has a built-in heater (not shown).

Thus, in the injection molding machine, when the molding material 102 such as pellet resin is charged into the hopper 111 from the input port 111a of the hopper 111, the molding material 102 drops in the hopper 111 due to its own weight, and the molding material 102 falls into the hopper 111. It is supplied into the heating cylinder 121 through the discharge port 111b that opens at the lower part of the hopper 111 and the supply port 121a of the heating cylinder 121 that communicates with the discharge port 111b. Here, in the heating cylinder 121, the screw 122 is rotationally driven by a drive device (not shown), and the molding material 102 supplied into the heating cylinder 121 is heated by a heater (not shown) built in the heating cylinder 121. While being melted, it is conveyed to the left side of FIG. 8 toward an injection port (injection nozzle) (not shown) by a rotating screw 122.

Then, the molded material (molten resin) 102 in the molten state is injected at a high pressure from an injection port (injection nozzle) (not shown) opened at the tip of the heating cylinder 121 into a cavity in a mold (not shown), and into the cavity. The injected molding material (molten resin) 102 is cooled and solidified in the mold, whereby a product having a desired shape (the same shape as the cavity) is manufactured.

By the way, regarding the injection molding machine, Patent Document 1 describes that in an injection molding machine for molding a polyester resin container, an opening is provided in the side wall of the resin supply part, and the resin supply part and the resin melting part are provided through the opening. A molding method has been proposed in which the production of aldehydes as by-products is suppressed by supplying a resin material in a reduced oxygen concentration atmosphere state due to a reduced pressure state or an inert gas atmosphere state.

Japanese Unexamined Patent Publication No. 2006-110815

In a conventional injection molding machine including the injection molding machine disclosed in Patent Document 1, as shown in FIG. 8, since the hopper 111 is in direct contact with the high temperature heating cylinder 121, the heat of the heating cylinder 121 is generated by the hopper. It conducts to 111, and this heat heats the molding material 102 in the hopper 111. When the molding material 102 in the hopper 111 is heated in this way, the molding materials 102 are in close contact with each other to form a bridge, which causes a problem that the supply of the molding material 102 to the heating cylinder 121 is hindered.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an injection molding machine capable of preventing adhesion between molding materials in a hopper and smoothly supplying the molding materials to an injection device. To do.

In order to achieve the above object, the first invention is to melt a supply device including a hopper into which a molding material is charged from a charging port and a molding material supplied from a discharge port of the hopper of the supply device. In an injection molding machine provided with an injection device for injecting a mold from an injection port into a mold, a heat insulating means is provided between the hopper and the injection device.

Here, the heat insulating means may be composed of a heat insulating material, an air layer, or a vacuum layer.

In the second invention, a supply device including a hopper into which a molding material is charged from an injection port and a molding material supplied from the discharge port of the hopper of the supply device are melted, and the molding material is transferred from an injection port to a mold. In an injection molding machine provided with an injection device for injecting and injection, a cooling means is provided between the hopper and the injection device.

Here, the cooling means may be configured by a cooling passage through which a cooling medium flows. In this case, the cooling medium may be air or water. Further, the cooling means may be configured to inject air as the cooling medium from the inner peripheral surface of the hopper toward the inside of the hopper. In this case, a plurality of injection ports may be formed on the inner peripheral surface of the hopper in the circumferential direction, and the air ejected from these injection ports may be applied to the inner wall slope of the hopper and flow upward.

According to the first invention, since the heat insulating means is provided between the hopper and the injection device, the heat conduction from the high temperature injection device to the hopper is blocked by the heat insulating means, and the molding materials in the hopper are fused by heat. Is prevented and the molding material is smoothly supplied to the injection device.

According to the second invention, since the hopper is cooled by the cooling means interposed between the hopper and the injection device and the temperature rise thereof is suppressed, the molding materials in the hopper are prevented from being fused by heat. Therefore, the molding material is smoothly supplied to the injection device.

It is a breaking side view which shows the whole structure of the injection molding machine which concerns on Embodiment 1 of 1st invention. It is a vertical cross-sectional view of the injection molding machine main part (hopper part) which concerns on Embodiment 1 of 1st invention. It is a vertical sectional view of the injection molding machine main part (hopper part) which concerns on Embodiment 2 of 1st invention. It is a vertical cross-sectional view of the injection molding machine main part (hopper part) which concerns on Embodiment 1 of 2nd invention. FIG. 4 is a cross-sectional view taken along the line AA of FIG. It is a vertical cross-sectional view of the injection molding machine main part (hopper part) which concerns on Embodiment 2 of 2nd invention. FIG. 6 is a cross-sectional view taken along the line BB of FIG. It is a vertical sectional view of the main part (hopper part) of the conventional injection molding machine.

[First invention]
<Embodiment 1>
Embodiment 1 of the first invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a broken side view showing the overall configuration of the injection molding machine according to the first invention, FIG. 2 is a vertical sectional view of a main part (hopper part) of the injection molding machine, and the injection molding machine 1 according to the present invention is As shown in FIG. 1, a supply device 10 including a hopper 11, an injection device 20 for injecting a molding material (hereinafter referred to as “pellet resin”) 2 supplied from the hopper 11, and a cavity C are formed therein. It is configured to include a mold 30 and a mold clamping device 40 that opens and closes the mold 30 while supporting the mold 30. Although not shown, the injection molding machine 1 includes a take-out device for taking out a molded product which is a product from the mold 30, a cooling water supply device for supplying cooling water to the mold 30, and an injection molding machine 1. A control device for controlling the operation, an operation panel equipped with various switches, a display panel, and the like are provided.

Here, the hopper 11 provided in the supply device 10 is a substantially cylindrical tank that stands vertically, and a circular hole-shaped input port 11a is opened on the upper surface thereof. Further, as shown in FIG. 2, the lower inner wall of the hopper 11 is formed in a shape narrowed downward in a tapered shape, and a circular hole-shaped discharge port 11b is formed in the center thereof. There is. Here, in the present embodiment, the inlet 11a and the outlet 11b of the hopper 11 overlap each other in a plan view (see FIG. 2). Although not shown, the supply device 10 includes an automatic discharge port opening / closing device for measuring the supply amount of the pellet resin 2 from the hopper 11 to the injection device 20, and hot air to the pellet resin 2 charged into the hopper 11. A hopper dryer is provided for stirring the pellet resin 2 while feeding the pellet resin 2.

The injection device 20 is a device that conveys the pellet resin 2 supplied from the hopper 11 while melting it by heating with a heater, and injects the molten resin into the mold 30, and is a heating cylinder arranged long in the horizontal direction. A 21 and a screw 22 rotatably inserted and supported in the heating cylinder 21 are provided. Here, a heater (not shown) is built in the heating cylinder 21, and as shown in FIG. 1, the tip of the heating cylinder 21 is injected to inject the molten resin toward the mold 30 at a high pressure. A nozzle (injection port) 23 is attached. The screw 22 is rotationally driven by a drive device (not shown) using a motor or the like as a drive source, and the operation start / stop timing of the drive device is controlled by a control device (not shown).

Here, as shown in FIG. 2, a circular hole-shaped supply port 21a is formed in a part of the heating cylinder 21, and the supply port 21a communicates with a discharge port 11b that opens at the bottom of the hopper 11. are doing.

The mold 30 is for cooling and solidifying the molten resin injected from the injection device 20 in the cavity C to obtain a molded product (product) having a desired shape, and is a fixed mold as shown in FIG. It is composed of 31 and a movable type 32. Here, in a state where the fixed mold 31 and the movable mold 32 are closed as shown in FIG. 1, a cavity C having the same shape as the molded product (product) is formed between the fixed mold 31 and the movable mold 32. Although not shown, the mold 30 is provided with a cooler.

The mold clamping device 40 is a device that opens and closes the fixed mold 31 and the movable mold 32 of the mold 30 by hydraulic pressure, and as shown in FIG. 1, the hydraulic cylinder 41 and the hydraulic cylinder 41 in the horizontal direction (FIG. 1). A piston 42 slidably fitted in the left-right direction of the mold 30 is provided, and a movable mold 32 of the mold 30 is attached to the piston 42. An oil chamber S1 and an oil chamber S2 partitioned by the piston 42 are formed in the hydraulic cylinder 41.

Thus, when the mold 30 is closed by the mold clamping device 40 configured as described above, hydraulic pressure is supplied to one of the oil chambers S1. Then, the piston 42 slides to the right in FIG. 1 together with the movable mold 32 of the mold 30, and the mold 30 is closed as shown in order for the movable mold 32 to abut on the fixed mold 31. On the other hand, when the mold 30 is opened, hydraulic pressure is supplied to the other oil chamber S2. Then, since the piston 42 slides to the left in FIG. 1 together with the movable mold 32, the mold 30 is opened in order to separate the movable mold 32 that was in contact with the fixed mold 31 from the fixed mold 31.

By the way, in the present embodiment, as shown in FIG. 2, a ring plate-shaped heat insulating material 50 as a heat insulating means is interposed between the hopper 11 and the heating cylinder 21.

Next, the operation of the injection molding machine 1 configured as described above will be described.

When molding a resin product using the injection molding machine 1 according to the present embodiment, a predetermined amount of pellet resin 2 is charged into the hopper 11 from the charging port 11a of the hopper 11 by a feeding device (not shown). .. Then, the plurality of pellet resins 2 introduced fall into the hopper 11 due to their own weight, but in the present embodiment, as shown in FIG. 2, a heat insulating material 50 is interposed between the hopper 11 and the heating cylinder 21. As described later, the heat conduction from the high-temperature heating cylinder 21 heated by the heater (not shown) to the hopper 11 is effectively blocked by the heat insulating effect of the heat insulating material 50. Therefore, the pellet resin 2 in the hopper 11 is not melted by heat, and the pellet resin 2 is not fused to each other to form a bridge. As a result, the pellet resin 2 is smoothly supplied from the hopper 11 to the heating cylinder 21.

Thus, when the pellet resin 2 is smoothly supplied into the heating cylinder 21 of the injection device 20, these pellet resins 2 are tipped inside the heating cylinder 21 by the screw 22 which is rotationally driven (FIGS. 1 and 1). It is transported to the left side of 2), but in the process, it is heated by a heater (not shown) built in the heating cylinder 21 and melted. Then, this molten resin is injected at high pressure from the injection nozzle 23 (see FIG. 1) attached to the tip of the heating cylinder 21 into the cavity C of the mold 30 in the closed state as shown in FIG. It solidifies by being cooled inside. As a result, a resin molded product having the same shape as the cavity C is formed in the mold 30, and the movable mold 32 is moved by the mold clamping device 40 to open the mold 30 and take out a robot hand or the like (not shown). By taking out the resin molded product from the mold 30, a series of injection molding operations is completed.

As is clear from the above description, according to the present embodiment, since the heat insulating material 50 is interposed between the hopper 11 and the heating cylinder 21, heat conduction from the heating cylinder 21 to the hopper 11 is caused by the heat insulating material 50. It is blocked, and the effect that the pellet resin 2 in the hopper 11 is prevented from being fused by heat and the pellet resin 2 is smoothly supplied to the heating cylinder 21 can be obtained.

<Embodiment 2>
Next, Embodiment 2 of the first invention will be described below with reference to FIG.

FIG. 3 is a vertical cross-sectional view of the main part (hopper part) of the injection molding apparatus according to the second embodiment of the first invention. In this figure, the same elements as those shown in FIG. 2 are designated by the same reference numerals. Therefore, the description of them again will be omitted below.

The basic configuration of the injection molding machine according to the present embodiment is the same as that shown in FIG. 1, except for the form of the heat insulating means interposed between the hopper 11 and the heating cylinder 21. That is, in the present embodiment, as shown in FIG. 3, an air layer 51 or a vacuum layer 52 is interposed between the hopper 11 and the heating cylinder 21 as a heat insulating means. Specifically, a recess 11c is formed on the bottom surface of the hopper 11, and a sealed space is formed on the bottom of the hopper 11 by covering the bottom opening of the recess 11c with a highly heat-insulating seal plate 53. Then, the closed space is made into an air layer 51 in which air having a small thermal conductivity exists, or the closed space is made into a vacuum layer 52 by evacuating the closed space.

Therefore, according to the present embodiment, since the air layer 51 or the vacuum layer 52 is interposed between the hopper 11 and the heating cylinder 21, the heat conduction from the heating cylinder 21 to the hopper 11 is the air layer 51 or the vacuum layer 52. The effect is that the pellet resin 2 in the hopper 11 is prevented from being fused due to heat and the pellet resin 2 is smoothly supplied to the heating cylinder 21 as in the first embodiment. Be done.

[Second invention]
Next, an embodiment of the second invention will be described.

<Embodiment 1>
FIG. 4 is a vertical sectional view of a main part (hopper portion) of the injection molding machine according to the second invention, and FIG. 5 is a sectional view taken along line AA of FIG. 4, which is also shown in FIG. The same elements are designated by the same reference numerals, and the description thereof will be omitted below.

The basic configuration of the injection molding machine according to the present embodiment is the same as that shown in FIG. 1, except that a cooling means is provided between the hopper 11 and the heating cylinder 21. That is, in the present embodiment, a cooling passage 60 is formed between the hopper 11 and the heating cylinder 21, and a cooling medium such as air or water is allowed to flow through the cooling passage 60.

Specifically, as shown in FIG. 4, a recess 11c is formed on the bottom surface of the hopper 11, and the bottom opening of the recess 11c is covered with a ring plate-shaped seal plate 61 having high heat insulation. A cooling passage 60 is formed at the bottom. Then, as shown in FIG. 5, a plurality of (three in the illustrated example) inflow ports 60a are opened on one side of the cooling passage 60, and a plurality of (three in the illustrated example) outlets 60b are opened on the other side. Is open. Then, when the air discharged from the air compressor (not shown) flows into the cooling passage 60 from each inflow port 60a, this air flows through the cooling passage 60 as shown by an arrow in FIG. 5, and the bottom of the hopper 11 To cool. Then, the air used for cooling the hopper 11 is discharged into the atmosphere from each discharge port 60b. By continuously repeating such an action, the lower part of the hopper 11 is cooled by air, so that the pellet resin 2 in the hopper 11 is not heated and fused to each other, and the pellet resin 2 is heated. The supply to the cylinder 21 is smooth. Here, when the pellet resin 2 in the hopper 11 dislikes moisture, it is desirable to let dry air flow through the cooling passage 60.

Alternatively, if the cooling water discharged from the water pump (not shown) flows into the cooling passage 60 from each inflow port 60a, the cooling water flows through the cooling passage 60 as shown by an arrow in FIG. 5, and the hopper 11 Cool the bottom of the. Then, the cooling water used for cooling the hopper 11 is discharged from each discharge port 60b to the outside of the cooling passage 60. By continuously repeating such an action, the bottom portion of the hopper 11 is cooled by the cooling water, so that the pellet resin 2 in the hopper 11 is not heated and fused to each other, and the pellet resin 2 is heated. The supply to the cylinder 21 is smooth.

In the present embodiment, each of the three inflow ports 60a and the discharge port 60b is opened in the cooling passage 60, but the number of these inflow ports 60a and the discharge port 60b is arbitrary.

<Embodiment 2>
Next, Embodiment 2 of the second invention will be described below with reference to FIGS. 6 and 7.

FIG. 6 is a vertical sectional view of a main part (hopper portion) of the injection molding apparatus according to the second embodiment of the second invention, and FIG. 7 is a sectional view taken along line BB of FIG. 6. Also in these views, FIG. The same elements as those shown in the above are designated by the same reference numerals, and the description thereof will be omitted below.

In the present embodiment, the cooling means is configured to inject air as a cooling medium from the inner peripheral surface of the hopper 11 toward the inside of the hopper 11. Specifically, as shown in FIGS. 6 and 7, a ring channel-shaped flow path member 70 is fitted on the outer periphery of the bottom of the hopper 11, and the flow path member 70 is fitted on the bottom of the hopper 11. A plurality of linear (eight in the illustrated example) air passages 71 that communicate the inside and the inside of the hopper 11 are formed horizontally and radially (see FIG. 7). Therefore, on the inner wall slope 11d at the bottom of the hopper 11, a plurality of ends (eight in the illustrated example) of the air passages 71 are opened at equal intervals in the circumferential direction as injection ports 71a. An inflow port 70a is opened in a part of the outer circumference of the flow path member 70.

Thus, when air (compressed air) discharged from an air compressor (not shown) flows into the flow path member 70 from the inflow port 70a, this air flows into the plurality of air passages 71 formed at the bottom of the hopper 11. The air flows through the inside toward the center of the hopper 11 and is horizontally injected from each injection port 71a that opens to the inner wall slope 11d at the bottom of the hopper 11. Then, as shown by an arrow in FIG. 6, the air injected from each injection port 71a hits the inner wall slope 11a at the bottom of the hopper 11 and the flow direction is changed upward, and in the process of flowing upward, the air inside the hopper 11 The pellet resin (not shown in FIG. 7) is cooled. Therefore, the pellet resins in the hopper 11 are not heated and fused to each other, and the pellet resins are smoothly supplied to the heating cylinder 21. Here, in order to allow air to flow upward in the hopper 11, it is desirable that the inclination angle of the inner wall slope 11d of the hopper 11 is 45 °. When the pellet resin in the hopper 11 dislikes moisture, it is desirable to use dry air as the air to be jetted into the hopper 11.

The number of air passages 71 formed in the hopper 11 and the inflow ports 70a formed in the flow path member 70 is arbitrary, and is not limited to the number shown in the present embodiment.

Further, the first and second inventions are not limited to the embodiments described above, and various modifications can be made within the scope of claims and the technical ideas described in the specification and drawings. Of course it is possible.

1 Injection molding machine 2 Pellet resin (molding material)
10 Supply device 11 Hopper 11a Hopper inlet 11b Hopper discharge port 11c Hopper recess 11d Hopper inner wall slope 20 Injection device 21 Heating cylinder 21a Heating cylinder supply port 22 Screw 23 Injection nozzle (injection port)
30 Mold 31 Fixed mold 32 Movable mold 40 Mold clamping device 41 Hydraulic cylinder of mold clamping device 42 Piston of mold clamping device 50 Insulation material (insulation means)
51 Air layer (insulation means)
52 Vacuum layer (insulation means)
53 Seal plate 60 Cooling passage (cooling means)
60a Cooling passage inflow port 60b Cooling passage outlet 61 Seal plate 70 Flow path member 70a Flow path member inflow port 71 Air passage 71a Air passage injection port C Cavity S1, S2 Oil chamber

Claims (8)

A supply device including a hopper in which a molding material is charged from a charging port, and an injection device that injects the molding material from an injection port into a mold while melting the molding material supplied from the discharge port of the hopper of the supply device. In an injection molding machine equipped with
An injection molding machine characterized in that a heat insulating means is interposed between the hopper and the injection device. The injection molding machine according to claim 1, wherein the heat insulating means is made of a heat insulating material. The injection molding machine according to claim 1, wherein the heat insulating means is composed of an air layer or a vacuum layer. A supply device including a hopper in which a molding material is charged from an injection port, and an injection device that injects the molding material from an injection port into a mold while melting the molding material supplied from the discharge port of the hopper of the supply device. In an injection molding machine equipped with
An injection molding machine characterized in that a cooling means is interposed between the hopper and the injection device. The injection molding machine according to claim 4, wherein the cooling means is composed of a cooling passage through which a cooling medium flows. The injection molding machine according to claim 5, wherein the cooling medium is air or water. The injection molding machine according to claim 5, wherein the cooling means is configured to inject air from the inner peripheral surface of the hopper toward the inside of the hopper. The seventh aspect of claim 7 is characterized in that a plurality of injection ports are formed on the inner peripheral surface of the hopper in the circumferential direction, and the air ejected from these injection ports is applied to the inner wall slope of the hopper and flows upward. The injection molding machine described.

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