JPH04373B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a magnetic field generator for a plastic magnet injection molding machine.

(b) Prior Art When injection molding anisotropic plastic magnets, it is necessary to apply a magnetic field during the molding process, and there are three methods for applying this magnetic field. In other words, there are two methods: incorporating a coil for generating a magnetic field inside the mold, placing the coil around the outside of the mold clamping device of an injection molding machine, and fixing the coil within the area surrounded by four tie bars. How to place
(see publication number).

(c) Problems to be solved by the invention The method of incorporating a coil inside a mold has the following drawbacks. In other words, space is required to incorporate the coil inside the mold, which increases the size of the mold, necessitating the use of a large injection molding machine, and the need for a multi-cavity mold. In some cases, the number of products taken decreased and productivity decreased.

On the other hand, the method of arranging the coil around the outer periphery of the mold clamping device has the following drawbacks. In other words, in order to prevent the magnetic flux from being shunted to other parts, it is necessary to use a special machine with non-magnetic materials other than the mold, and because of the outer circumferential coil, there is generally a large leakage of magnetic flux, and the necessary effective magnetic flux is In order to ensure this, it was necessary to increase the generated magnetic flux. For this reason, the coil has become larger and its power consumption has also increased. Another problem was that devices affected by magnetism could not be used in the vicinity of the coil due to magnetic flux leakage. In addition, it is necessary to move the coil every cycle to take out the molded product, which requires a special drive device and reduces efficiency.

The above-mentioned two drawbacks can be solved by fixing the coil in the area surrounded by four tie bars, but this method is not disclosed in Japanese Patent Application Laid-Open No. 55-84640 or Japanese Utility Model Application No. 58-7633. The method shown in the publication has the following drawbacks. That is, since the electromagnet (or coil) is not arranged so as to surround the molded product cavity, it is difficult to cause the generated magnetic field to effectively act on the molded product. In other words, a current is passed through the coil to generate a magnetic field at the magnetic pole part of the mold to magnetize the molded product, but since the coil is located away from the position surrounding the molded part, the magnetic pole of the mold After the magnetic field in the molded product cavity reaches saturation, even if the current flowing through the coil is increased, the magnetic field generated in the molded product cavity will hardly increase. For this reason,
There is a problem in that it becomes difficult to cause the generated magnetic field to effectively act on the molded product, making it impossible to improve the magnetic properties of the molded product. This is because if the coil is placed so as to cover the cavity of the molded product, the coil will get in the way when the molded product is taken out.

The object of the present invention is to solve the above-mentioned problems in the conventional magnetic field generator of a plastic magnet injection molding machine.

(d) Means for Solving the Problems The present invention provides a method for disposing a fixed plate side coil surrounding a fixed mold and a movable plate side coil surrounding a movable mold within an area surrounded by tie bars of a mold clamping device. The above problem is solved by arranging these coils and configuring them to be movable between the molding position and the mold attachment/detachment position. That is, the magnetic field generating device for the plastic magnet injection molding machine of the present invention has mold clamping devices 12 and 16 in which a movable platen 18 and a fixed platen 10 are connected by four tie bars 14. Panel side coil 32 and movable panel side coil 28
are placed within the area surrounded by four tie bars 14,
Fixed plate side coil moving device 4 attached to fixed plate 10 and connected to fixed plate side coil 32
0, a movable platen side coil moving device 36 attached to the movable platen 18 and connected to the movable platen side coil 28, a fixed platen side slide guide 34 arranged and fixed on the fixed platen 10 side, and a movable platen side coil moving device 36 attached to the movable platen side 18, and a fixed platen side slide guide 34 arranged and fixed on the fixed platen side. It has a movable platen side slide guide 30 whose arrangement is fixed, and the fixed platen side coil 32 is driven by the fixed platen side coil moving device 40 and guided by the fixed platen side slide guide 34. It is movable between a molding position that surrounds the fixed mold 26 and a mold removal position that exposes the fixed mold 26, and the movable platen side coil 28 is driven by the movable platen side coil moving device 36, and It is guided by the board-side slide guide 30 and is movable between a molding position where the movable mold 22 is surrounded and a mold removal position where the movable mold 22 is exposed. A fixed mounting plate 24 is arranged between the fixed platen 10 and the fixed mold 26 and is fixed to the fixed plate 10, and a fixed mounting plate 24 is arranged between the movable platen 18 and the movable mold 22 and attached to the movable mold 22. A fixed movable mounting plate 20 is provided so that the fixed plate side slide guide 34 is movably supported in the axial direction by the fixed plate side slide guide 3.
0 may be supported for axial movement by a movable mounting plate 20. Note that the inside brackets indicate corresponding members of the embodiment.

(E) Function During the forming operation, the coil on the fixed platen side remains at the molding position covering the outer periphery of the fixed mold, and the coil on the movable platen side moves to the mold open position and the molding position while covering the outer periphery of the movable mold. move between In the mold closed position,
The fixed plate side coil and the movable plate side coil are located at a position where their mutually facing end surfaces are in contact with each other, that is, at a forming position. In this state, a current is passed through both coils in advance to generate a magnetic field.
Molten plastic magnet material is injected into the molded part cavity. The magnetic flux generated thereby can be effectively applied to the molded product, and a molded product with a large magnetic force can be manufactured. When the mold is opened, the movable platen side coil moves to the mold opening position together with the movable mold and the movable platen. Therefore, both coils do not interfere with removing the molded product from the mold.

When replacing the mold, by operating the fixed plate side coil moving device and the movable plate side coil moving device while the mold is closed, the fixed plate side coil is moved to the mold attachment/detachment position close to the fixed plate, and the movable coil is Move the plate side coil to the mold attachment/detachment position close to the movable platen. Thereby, there is nothing on the outer periphery of the mold that will interfere with mold replacement, so that the mold can be replaced without any problem. After replacing the mold, the fixed platen side coil moving device and the movable platen side coil moving device are operated to return the fixed platen side coil and the movable platen side coil to the molding position so that they cover the outer periphery of the mold. As a result, preparations for molding using the replaced mold are completed, and a plastic magnet corresponding to the cavity shape can be molded.

(F) Embodiments Hereinafter, the present invention will be explained based on FIGS. 1 and 2 of the accompanying drawings showing embodiments thereof. First, the configuration will be explained.

The fixed platen 10 and the mold clamping cylinder 12 are connected by four tie bars 14, and the mold clamping piston 16 fitted into the mold clamping cylinder 12 is guided by the tie bars 14 and can move in the axial direction. It is connected to a movable platen 18. A movable mold 22 is attached to a movable mounting plate 20 fixed to the movable platen 18, and a fixed mold 26 is attached to a fixed mounting plate 24 fixed to the fixed platen 10. and the fixed mold 26 are arranged so as to face each other. A movable platen side coil moving cylinder 36 is attached to the movable platen 18 on the side opposite to the side on which the movable mounting plate 20 is attached. Piston rod 3 of the movable platen side coil moving cylinder 36
8 is connected to a movable platen side coil 28.
The outer periphery of the movable mounting plate 20 and the movable plate side coil 28
There is a slide guide 3 on the movable platen side between the inner peripheral part of
0 is placed. Movable plate side slide guide 3
As shown in FIG. 2, rollers 31 are arranged at right angles to each other, and are arranged at each corner of the movable mounting plate 20.
The movable platen side coil moving cylinder 36 moves in the axial direction between a molding position where the movable platen side coil 28 surrounds the illustrated movable mold 22 and a mold detachment position where the movable mold 22 on the left side of the figure is exposed. Thus, the movable platen side coil 28 can be driven. The movable platen side slide guide 30 can guide the movement of the movable platen side coil 28 in the axial direction. The amount of movement of the movable platen side slide guide 30 is half the amount of movement of the movable platen side coil 28, and supports the movable platen side coil 28 in an overhanging state. On the other hand, a fixed plate side coil moving cylinder 40 is formed on the fixed plate 10, and a piston rod 42 of this cylinder has a fixed plate side coil 32.
are connected. A fixed plate side slide guide 34 is arranged between the outer circumferential portion of the fixed mounting plate 24 and the inner circumferential portion of the fixed plate side coil 32. The fixed plate side slide guides 34 are of a type having rollers 35 like the above-described movable plate side slide guides 30, and are arranged at each corner of the fixed mounting plate 24. The fixed plate side coil moving cylinder 40 moves in the axial direction between the molding position where the fixed plate side coil 32 surrounds the illustrated fixed mold 26 and the mold removal position where the fixed mold 26 on the right side of the figure is exposed. The fixed plate side coil 32 can be driven to move. The fixed plate side slide guide 34 is connected to the fixed plate side coil 32.
can guide the axial movement of. In addition, as shown in FIG. 2, the movable platen side coil moving cylinder 36
fully extend the piston rod 38,
With the movable platen side coil 28 stopped at the position shown in the figure, by extending the piston rod 42 of the fixed platen side coil moving cylinder 40, the fixed platen side coil 32 is pressed and fixed against the movable platen side coil 28 as shown in the figure. It is possible to do so. That is,
Both coils 28, 32 can be positioned and fixed relative to both plates 18, 10. Note that the fixed platen 10 and the fixed mounting plate 24 are provided with a hole 44 and a hole 46, respectively, for receiving an injection nozzle (not shown). Further, the fixed mold 26 is provided with a sprue 48. In addition, tie bar 14
is made thicker than necessary to receive the mold clamping force generated by the mold clamping cylinder 12. By doing so, as will be described later, a closed loop is formed through the magnetic flux generated by the movable plate side coil 28 and the fixed plate side coil 32, and leakage of magnetic flux to the outside is reduced.

Next, the effect will be explained. First, the movable platen 18 located at the mold opening position to the left in FIG.
moves to the right for molding, resulting in the state shown in FIG. 1 in which the movable mold 22 and the fixed mold 26 are brought into close contact. At this time, the movable platen side coil moving cylinder 36
By supplying hydraulic pressure to the oil chamber on the piston head side of the piston head and fully extending the piston rod 38, the movable plate side coil 28 is positioned at the position shown in the figure, and the oil pressure on the piston head side of the fixed plate side coil moving cylinder 40 is By supplying hydraulic pressure to the chamber and extending the piston rod 42, the stationary plate side coil 32 is pressed against the movable plate side coil 28 as shown. Adjust the extension stroke of both cylinders in advance according to the mold thickness dimensions, etc. As a result, the movable platen side coil 28 and the fixed platen side coil 32 are fixed at the molding position where the end surfaces facing each other are in contact with each other and surround the outer peripheries of both molds 22 and 26, respectively. In this state, molten resin is injected from an injection nozzle (not shown). The molten resin enters the mold through the sprue 48 and a molded product 50 is formed. When injecting molten resin, the movable plate side coil 28 and the fixed plate side coil 32
A magnetic field is generated by passing an electric current through the Movable plate side coil 28 and fixed plate side coil 32
The magnetic flux generated by this forms a closed loop as shown in FIG. One loop has a movable platen 18,
This loop passes through the movable mounting plate 20, the movable mounting plate 22, the fixed mold 26, the fixed mounting plate 24, the fixed plate 10, and the tie bar 14 in this order, and the other loop passes through the movable mounting plate 18, the movable mounting plate 20, and the movable mounting plate 20. This loop passes through the mold 22, fixed mold 26, fixed mold mounting plate 24, fixed platen 10, tie bar 14, mold clamping cylinder 12, and mold clamping piston 16 in this order. This magnetic flux acts on the molded product 50 before solidification, and the magnetization direction of the magnetic powder in the molten resin becomes constant and solidifies as it is, so that a molded product of anisotropic plastic magnet is obtained. At this time, in the conventional coil fixed to the movable platen 18 or fixed platen 10, when the magnetization of the magnetic pole parts of the movable mold 22 and the fixed mold 26 is saturated, even if the current flowing through the coil is increased, the molded product Although the magnetic field generated in the cavity part hardly increases, in the present invention, the movable platen side coil 28 and the fixed platen side coil 32
are located so as to surround the molded product cavity, so as the magnetomotive force (number of coil turns x current) increases, the magnetic field generated in the molded product cavity increases, causing a large magnetic flux to be applied to the molded product 50. It can be made to work. When the molding is completed, the movable platen 18 moves to the left in FIG.
is taken out. Since the movable platen side coil 28 also moves together with the movable mold 22 and is located at the mold open position, the movable platen side coil 28 moves when taking out the molded product 50.
There is no need to specifically move only 8. The next and subsequent molding operations are performed while continuing to supply hydraulic pressure to the oil chamber on the piston head side of the coil moving cylinder 40 on the fixed platen side, and also to the oil chamber on the piston head side of the coil moving cylinder 36 on the movable platen side. will be held.

The movable mold 22 and fixed mold 26 are removed as follows. First, with the mold closed, hydraulic pressure is supplied to the oil chamber on the rod side of the coil moving cylinder 36 to shorten the piston rod 38, thereby moving the coil 28 on the movable platen side from the molding position shown in FIG. 18 side mold attachment/detachment position (position where the movable plate side coil 28 covers the outer periphery of the movable mold mounting plate 20)
Move to. Similarly, by supplying hydraulic pressure to the oil chamber on the rod side of the fixed plate side coil moving cylinder 40 to shorten the piston rod 42, the fixed plate side coil 32 is also moved from the molding position to the mold attachment/detachment position on the fixed plate 34 side (fixed plate side). The panel side coil 32 is fixed type mounting plate 24
position) to cover the outer periphery of the Since the movable plate side coil 28 and the fixed plate side coil 32 are supported by the movable plate side slide guide 30 and the fixed plate side slide guide 34, respectively, the above movement is performed smoothly. As shown above, the movable platen side coil 2
8 and the fixed plate side coil 32 are moved, the movable mold 22 and the fixed mold 26 are supported by wires, for example, and the mounting bolts of the movable mold 22 (not shown) and the mounting bolts of the fixed mold 26 (not shown) are supported. Then, move the movable platen 18 to the left (mold opening direction) in FIG. 1, lift up the movable mold 22 and the fixed mold 26, and take them out. When installing the mold, you can perform the work in the reverse order of the above.

In addition, in the above explanation, as a coil moving device,
Although the coil moving cylinders 36 and 40 are used, a device using a screw feeding mechanism or the like may also be used.

In addition, in the above explanation, the movable platen 18 and the movable mold 22
A movable mounting plate 20 is provided between the fixed plate 10 and the fixed mold 26, and a fixed mounting plate 24 is provided between the fixed plate 10 and the fixed mold 26, and the slide guides 30, 34 are supported by both mounting plates 20, 24. However, the mounting plates 20 and 24 are not provided, but protrusions corresponding to the mounting plates 20 and 24 are formed on the movable plate 18 and the fixed plate 10, respectively, and the slide guides 30 and 34 are formed by the outer periphery of the protrusions. may be supported.

It is clear that the present invention can also be applied to injection molding machines with mold clamping methods (direct pressure type, special direct pressure type, toggle type, etc.) other than those described in the embodiments.

(G) Effects of the Invention As described above, in the magnetic field generating device for the plastic magnet injection molding machine according to the present invention, the magnetic field generating coil can be positioned so as to surround the molded product cavity, so that a large magnetic flux can be applied to the molded product. can be made to work. Thereby, the magnetic properties of the molded article can be improved. Moreover, when the mold is opened, the magnetic field generating coil on the movable platen side moves together with the movable platen, so that it does not interfere with taking out the molded product. Further, when replacing the mold, the magnetic field generating coil can be moved to a position away from the molded product cavity, so that it does not interfere with the mold replacement.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a magnetic field generating device for a plastic magnetic injection molding machine according to the present invention, and FIG. 2 is a view taken along the line -- in FIG. 10... fixed plate, 12... mold clamping cylinder, 14
...Diver, 16...Mold clamping piston, 18...
Movable platen, 20...Movable mounting plate, 22...Movable type, 24...Fixed type mounting plate, 26...Fixed type, 2
8...Movable plate side coil (magnetic field generation coil), 3
0...Movable plate side slide guide, 31...Roller, 32...Fixed plate side coil (magnetic field generation coil), 34...Fixed plate side slide guide, 35...
...Roller, 36...Movable plate side coil moving cylinder, 38...Piston rod, 40...Fixed plate side coil moving cylinder, 42...Piston rod,
44, 46...hole, 48...sprue, 50...
Molding.

Claims (1)

[Claims] 1. A movable platen 18 and a fixed platen 10 have mold clamping devices 12 and 16 connected by four tie bars 14, and a coil 32 on the fixed platen side and a coil 28 on the movable platen side. However, in a magnetic field generating device for a plastic magnet injection molding machine, which is arranged in an area surrounded by four tie bars 14, a fixed plate provided on a fixed plate 10 and connected to a coil 32 on the fixed plate side is used. Panel side coil moving device 40
and a movable platen side coil moving device 3 provided on the movable platen 18 and connected to the movable platen side coil 28.
6, a fixed plate side slide guide 34 which is arranged on the inner circumferential side of the fixed plate side coil 32 and can guide the fixed plate side coil 32;
It has a movable platen side slide guide 30 which is arranged on the inner circumferential side of the movable platen side coil 28 and can guide it. The movable platen side coil 28 is movable between a molding position that surrounds the movable mold 22 and a mold demounting position that exposes the movable mold 22. A magnetic field generator for a plastic magnet injection molding machine. 2. A fixed mounting plate 24 disposed between the fixed platen 10 and the fixed mold 26 and fixed to the fixed plate 10, and the movable platen 18 and the movable mold 2.
2, and a movable mounting plate 20 fixed to the movable mold 22 is provided, and the fixed plate side slide guide 34 is movable in the axial direction by the fixed mounting plate 24. 2. A magnetic field generating device for a plastic magnet injection molding machine according to claim 1, wherein said movable plate side slide guide is supported movably in the axial direction by a movable mounting plate.