JPH028566B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves mixing a thermosetting resin such as unsaturated polyester with a filler such as calcium carbonate, reinforcing fibers such as glass fiber, and additives such as a catalyst, a mold release agent, and a coloring agent. This invention relates to a device for supplying a highly viscous molding material called BMC (or SMC depending on the shape) to an injection unit of an injection molding machine.

Conventionally, as a device for supplying the above BMC material to an injection unit equipped with an injection screw and a screw cylinder, a large diameter piston for pushing the material was fitted into a hopper that was connected to the material receiving port of the screw cylinder. However, a structure is known in which the piston constantly presses the entire molding material in the hopper toward the screw, so that the molding material in the hopper is gradually pushed into the screw cylinder. However, with conventional devices of this type,
Since the material is supplied under pressure from the material receiving port to the entire diameter of the screw by the piston, a large stress is applied in the direction of pushing back the material as the screw rotates, which causes the viscosity of the BMC material to decrease. If the viscosity of the material is not too high, the glass fiber etc. and the main material may easily separate, and the material may leak outward from the gap between the piston and the inner surface of the hopper. The material is not easily absorbed into the screw.

Furthermore, pressure is constantly applied to the material in the hopper, making it extremely hard, making it difficult to replace the material, and when the pushing piston is pulled up above the hopper when replenishing material, a large amount of material is deposited on the piston. This material tends to adhere to the material and fall outside by hitting a movable hopper for replenishing the material. In addition, since a large pushing pressure is applied to the material inside the hopper, the hopper cannot be made too large, and when processing a large amount of material, the number of times the material must be fed increases, making it inefficient and difficult to control the operation and control. Wiring problems in the electrical system are also more likely to occur. Furthermore, in recent years, BMC materials have come in various shapes, not only in bulk but also in plate shapes (including materials commonly called SMC). is difficult to apply, etc.
There were various shortcomings.

The present invention eliminates the drawbacks of the conventional device as described above,
The molding material can be smoothly supplied to the injection screw, the material is well fed into the screw, and the material can be efficiently supplied to the injection unit, resulting in excellent mass productivity. The purpose of this invention is to provide a material supply device that can be applied to various BMC materials such as shapes.

In other words, the device of the present invention has a material pushing casing that communicates with a material receiving port provided on the peripheral wall of the screw cylinder, which has two-thirds of the diameter of the injection screw.
A material pushing ram having the following width is arranged so that it can move forward and backward toward the screw, and the extension line of the center line of the ram is deviated from the direction toward the axis of the screw toward the direction of rotation of the screw. The material receiving port is formed to have a width comparable to or greater than the width of the ram, and a hotspa casing having a larger capacity than the material pushing casing is provided, the tip of which is connected to the material pushing casing and the material receiving casing. A hopper piston is connected to a material pushing casing near the material receiving port so as to communicate with the inlet, and a hopper piston is provided in the hopper casing so as to be movable toward the material pushing casing. are arranged at almost right angles to each other, and a ram operating device for moving the ram forward and backward, and a hopper piston operating device for urging the hopper piston toward the material pushing casing during the operation of the ram, thereby allowing the hopper piston to push the material. The molding material is divided into parts by a material pushing ram and then pushed into a screw cylinder.

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 to 4, A is an injection unit of an injection molding machine, and includes an injection screw 1 arranged approximately horizontally, and a screw cylinder 2 surrounding the screw 1. The screw cylinder 2 has an injection port (not shown) at the tip thereof to a mold clamping device, etc., and a material receiving port 3 is provided in an appropriate range of the rear peripheral wall. The screw 1 above is
It is rotated in the direction shown by arrow A in FIG. 2 when required by a drive device not shown.

B is a material pushing device, and the material receiving port 3 is
a material-pushing ram 5 fitted into the casing 4 so as to be movable toward the screw 1; and a hopper communicating with a predetermined range of the front part of the material-pushing casing 4. The hopper piston 7 is provided with a casing 6 and a hopper piston 7 fitted into the hopper casing 6 so as to be able to move forward and backward toward the material-pushing casing 4. The material pushing ram 5 and the hopper piston 7 are arranged at substantially right angles to each other, and the tip of the hopper casing 6 is located near the material receiving port 3 so that it communicates with the material pushing casing 4 and the material receiving port 3. It is connected to the material pushing casing 4. The tip of the hopper casing 6 and the front part of the material-pushing casing 4 are commonly integrated, and the ram 5 is configured to advance and retreat in a direction across the hopper casing 6 at this portion. In this embodiment, the material pushing ram 5 and the hopper piston 7 are each arranged at an angle of approximately 45 degrees with respect to the horizontal direction.
The ram 5 is moved forward and backward in the direction of arrow B by an air cylinder 8 or a hydraulic cylinder as a ram operating device, and the hopper piston 7 is moved in the direction of arrow C by an air cylinder 9 or a hydraulic cylinder as a hopper piston operating device. The ram is moved forward and backward, and is urged toward the material-pushing casing 4 during the ram operation.

The ram 5 and material pushing casing 4 are
It is formed into a flat shape with a width corresponding to the formation range of the material receiving port 3 in the front-rear direction. As shown in FIG. 2, the width l of the ram 5 as seen in a cross section perpendicular to the axial direction of the screw 1 is 2/3 or less of the diameter D of the injection screw 1, and usually 1/2 of the screw diameter D. A ram 5 is formed with a width of approximately On the other hand, the material receiving port 3 is formed to have a width comparable to or greater than the width of the ram 5, and a scraped portion is formed on the inner surface of the screw cylinder 2 on the forward side of the material receiving port 3 in the direction of screw rotation. By providing this, a material introduction space 10 is formed between the screw 1 and the outer periphery of the screw 1. Further, an extension line of the center line of the ram 5 is set on the screw 1 so that as the ram 5 moves forward, the molding material is pushed from the material receiving port 3 toward the material introducing space 10 forward in the direction of rotation of the screw.
The ram 5 and the casing 4 are arranged offset from the center of the ram 5 and the casing 4. The depth h of the material introduction space 10 is 0.05 to 0.35 of the screw diameter D.
It is desirable that the longitudinal length s of the material receiving port 10 be approximately 2 to 4 times the screw diameter D.

Further, the hotspa casing 6 is formed into a rectangular tube shape, and its tip wall 6a is connected to the material pushing casing 4.
The inner surface of the tip wall 6a forms a material pushing guide surface 11. One side wall of the hopper casing 6 has a material input port 12, and a hopper lid 13 that also serves as a material input guide is provided in the input port 12 so as to be openable and closable. It is designed to be locked. A limit switch 15 detects the forward end position of the hopper piston 7.

This material supply device can be applied to BMC materials in various shapes such as bulk shape and plate shape, and its operation will be explained below.

First, as shown by the solid line in FIG. 4, with the hopper piston 7 retracted and the hopper lid 13 open, a bulk or plate-shaped molding material 20 is removed.
is charged into the hotspa casing 6 from the material input port 12. When the molding material 20 is in the form of a plate as shown in the figure, a large number of molding materials are put in a stacked state. Next, the hopper lid 13 is closed, the hopper piston 7 is operated in the forward direction by the air cylinder 9, and the material pushing ram 5 is repeatedly moved back and forth by the air cylinder 8. As a result, the leading portion 20a of the molding material fed into the material pushing casing 4
The material is divided as the ram 5 advances and is supplied into the screw cylinder 2 from the material receiving port 3.

In this case, the supply of the molding material to the screw 1 and the biting performance are significantly improved compared to conventional devices. In other words, in the conventional structure in which material pushing pressure is applied to the entire diameter of the injection screw using a large-diameter pushing piston, large pushing pressure is also applied in the direction opposite to the rotational direction of the screw, and as the screw rotates, the material is Since excessive stress is applied in the direction of pushing back the molding material, it is difficult to supply the molding material smoothly and the ability to bite into the screw is also poor. On the other hand, according to this device, the molding material 20 is divided into pieces with a width of 2/3 or less of the screw diameter D by the ram 5, and the molding material 20 is pushed forward in the screw rotation direction from the material receiving port 3. As the screw 1 rotates, the molding material 20
It is smoothly fed into the screw cylinder 2 as it bites into the screw cylinder 2. In this case, the material receiving port 3 is the ram 5.
Since the width is equal to or greater than the width of the material, there is no possibility that the material would be squeezed and the back pressure would increase. Moreover, even if the material pushing pressure by the ram 5 is increased, the load is distributed in the direction of the hopper piston 7, so that no excessive stress is applied to the molding material, and the separation phenomenon of glass fibers is also prevented. Furthermore, if the material introduction space 10 is provided on the inner surface of the screw cylinder 2,
The resistance during biting is reduced and the biting performance is further improved.

On the other hand, the hopper piston 7 is connected to the material pushing ram 5.
As the leading portion 20a of the molding material is sequentially divided and supplied into the screw cylinder 2, the molding material 20 is gradually advanced. in this case,
Since the material pushing force into the screw 1 is applied by the ram 5, it is not necessary to apply a large pushing pressure to the entire material 20 in the hopper casing 6 by the hopper piston 7. Therefore, the molding material 20 in the hopper casing 6 is not extremely hardened, and it is also possible to increase the capacity of the hopper casing 6 in terms of pressure resistance and the like. By repeating the reciprocating motion of the ram 5 and operating the hopper piston 7, material is continuously supplied to the injection unit A. The hopper piston 7 and the material pushing ram 5 are controlled independently, so that even when the hopper piston 7 is retracted and the material is replenished into the hopper casing 6, the ram 5 operates to supply the material. It is possible to continue.

5 to 7 show another embodiment of the device according to the invention. In this embodiment as well, an injection unit A including an injection screw 21 and a screw cylinder 22 is provided with a material pushing ram 25 fitted in a material pushing casing 24 and a material pushing ram 25 fitted in a material pushing casing 24 above it as a material pushing device B. An air (or hydraulic) cylinder 28 that operates, a hopper piston 27 fitted in the hopper casing 26, and an air (or hydraulic) cylinder 29 that operates the hopper piston 27 are provided. However, the casing 24 for pushing the material
The ram 25 is arranged vertically above the material receiving port 23 of the screw cylinder 22, and the hopper casing 26 and the hopper piston 27 are arranged horizontally. The width of the ram 25 is 2/3 or less of the diameter of the screw 21, the ram 25 and the hopper piston 27 are arranged at right angles to each other, and the tip of the hopper casing 26 is connected to the material pushing casing 24. is the same as the first embodiment described above. Screw cylinder 22
The material introducing space 30 on the inner surface is formed over a predetermined range forward in the screw rotation direction from the material receiving port 23 that opens upward. Further, a shutter 33 that can be slid open and closed is provided at the material input port on the upper surface of the hopper casing 26, and a hopper guide 34 is provided above the shutter 33. The shutter 33 is opened and closed by an air cylinder 35.

According to the structure shown in this embodiment, when the molding material is in the shape of a rectangular parallelepiped or a plate in advance, this material can be efficiently introduced into the hotspa casing 26.
It has the advantage of being accommodating. That is, when the hoppa casing 6 is arranged in an inclined state as in the first embodiment, there is an advantage that the inner surface can also guide the material forward, but on the other hand, if the hopper casing 6 is arranged in a rectangular or rectangular shape, When a plate-shaped material is fed into the Hotsupa casing 6 from above, it is difficult to fit the material tightly into the Hotsupa casing 6, which tends to leave wasted space, which makes it difficult to take a large amount of material input. Additionally, there is a risk that air in the space may be mixed into the material during operation. On the other hand,
According to the structure of this embodiment, the material introduced into the hopper casing 26 from above through the hopper guide 34 is tightly accommodated in the hopper casing 26, and no wasted space is left, so that the capacity of the hopper casing 26 is reduced. It is possible to increase the amount of material input accordingly, improving the efficiency of inputting the material, and preventing air from being mixed into the material during operation. After inputting the material, the hopper piston 27 is operated in the forward direction and the ram 25 is reciprocated, thereby dividing the molding material into pieces of a certain width and sequentially pushing them into the screw cylinder 22.
This is the same as in the first embodiment.

In addition, this device can process a large number of molding materials continuously by combining it with a conveyor type material feeding device C shown in FIG. This material input device C is located at a position at a constant interval corresponding to the thickness of the material 20 with respect to the material input side end of the belt conveyor 41 that conveys the molding material 20.
Guide roller 4 having a large number of protrusions 43 on its circumferential surface
2, and above the material input space 44 between the end of the conveyor 41 and the guide roller 42,
It is equipped with a material pushing piston 45 that can move up and down and is operated by an air cylinder 46. The guide roller 42 is moved by a spring 47.
It is configured to be elastically pressed against the material fed into the material input space 44. Then, when the conveyor 41 is operated and the guide roller 42 is rotated by a motor (not shown), the conveyor 4
1 is dropped from the material input space 44 onto the hopper guide 34 of the hopper casing 26, and at this time, the protrusion 4 of the guide roller 42
3... scrapes off the corners of the molding material 20 so that the material falls smoothly, and the material falling speed is controlled by the rotational speed of the guide roller 42. Furthermore, the material is pressed by the piston 45 and accommodated in the hopper casing 26. Note that instead of the conveyor 41 and guide roller 42, as shown in FIG. 10, a conveyor 41' whose end on the material input side is inclined diagonally downward, and a conveyor 41' arranged at a predetermined distance from the conveyor 41' are provided. An elastically swingable guide conveyor 48 may also be used.

Furthermore, the operations of the material feeding device C and the material pushing device B can be automatically controlled using a limit switch or the like as shown in FIG.
That is, when the material feeding device C is stopped and the slide shutter 33 is closed by the air cylinder 35 after material feeding, the limit switch 51 is actuated in response to this, and the air cylinder 29 is actuated to open the hopper piston. 27 moves forward, and the material pushing ram 25 reciprocates to automatically feed material to the injection unit. When the hopper piston 27 advances to a predetermined position, the limit switch 53 operates accordingly, the operation of the air cylinder 29 is switched, and the hopper piston 27 moves backward. Next, hoppa piston 2
7 reaches the rear end position, the limit switch 54 operates, which operates the air cylinder 35 and opens the slide shutter 33. In addition, the limit switch 52 operates accordingly, thereby opening the drive device of the conveyor 41 and the guide rollers. The drive motor 42 operates, and the molding material is transferred to the hopper guide 3.
Dropped on 4th. After dropping the molding material, the conveyor 41 and guide rollers 42 are stopped by a counter (not shown) installed on the conveyor 41, and then the air supply circuit 55 to the actuating cylinder 46 of the material pushing piston 45 is opened. The piston 45 is moved downward and the molding material is forced into the hopper casing 26. When the piston 45 descends, the limit switch 57 operates to switch the solenoid valve 56 of the air supply circuit 55 to raise the piston 45. piston 45
When it reaches the rising end, the limit switch 58 operates to stop the piston 45 and close the slide shutter 33. By repeating this operation, the material is automatically transported, loaded,
The injection unit will be continuously supplied. Of course, it is also possible to perform these operations by operating a means switch.

As explained above, the molding material supply device of the present invention includes a material pushing ram and a hopper piston arranged at right angles to each other, and the molding material fed by the hopper piston is transferred by the ram to 2/3 or less of the diameter of the injection screw. Since the material is divided into widths of 1 and 2 and pushed forward in the direction of rotation of the screw inside the screw casing, the ability to feed and feed the material to the screw is improved. On top of that,
The material receiving port of the screw cylinder is made as wide as or wider than the width of the ram to prevent back pressure from increasing, and furthermore, the pressure applied to the material can be appropriately absorbed by the hopper piston. Because of the structure, these effects and the above-mentioned effects such as improving the penetration ability by the ram prevent excessive pressure from being applied to the entire material, and also prevent separation and loss of glass fibers, etc. . In addition, while the material is being fed from the large-capacity hotspa casing to the material pushing casing, the material can be sequentially fed in fixed amounts to the screw cylinder by the reciprocating operation of the ram. This method has many excellent effects, such as being able to process materials continuously, making it highly suitable for mass production, and being able to be applied to plate-shaped or large block-shaped materials.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the device of the present invention;
Fig. 2 is an enlarged sectional view of the part where material is pushed into the injection unit, Fig. 3 is a vertical sectional side view of the injection screw and screw cylinder, Fig. 4 is a sectional view of the device in use, and Fig. 5 is a diagram of the device of the present invention. 6 is a sectional view taken along the line - of FIG. 5, FIG. 7 is a view corresponding to FIG. FIG. 9 is an overall schematic diagram in the case of automation, and FIG. 10 is a schematic diagram showing another example of the material input device. A... Injection unit, 1... Screw for injection, 2... Screw cylinder, 3... Material receiving port, B... Material pushing device, 4... Casing for pushing material, 5... Ram for pushing material, 6... Hotupa casing, 7... Hotupa piston.

Claims (1)

[Claims] 1 A device that supplies a highly viscous molding material made by mixing a thermosetting resin with appropriate filling materials, reinforcing materials, etc., to an injection unit equipped with an injection screw and a screw cylinder, which A material-pushing ram having a width of 2/3 or less of the diameter of the screw is provided in a material-pushing casing that communicates with a material receiving port provided on the peripheral wall so as to be movable toward the screw and the center of the ram. The extension line of the line is arranged so as to be deviated from the direction toward the axis of the screw toward the direction of rotation of the screw, and the material receiving port is formed to have a width comparable to or greater than the width of the ram. A hopper casing with a larger capacity than the material pushing casing is connected to the material pushing casing near the material receiving port so that its tip communicates with the material pushing casing and the material receiving port, and A hopper piston is equipped to move forward and backward toward the material-pushing casing, and the material-pushing ram and the hopper piston are arranged substantially at right angles to each other, and a ram operating device that moves the ram forward and backward; By providing a hopper piston actuating device that urges the hopper piston toward the material-pushing casing, the molding material pushed by the hopper piston and sent to the material-pushing casing is divided by the material-pushing ram into the width of the ram. 1. A molding material supply device for an injection molding machine, characterized in that it is configured to be pushed into a screw cylinder while