JPH0523307Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an injection molding machine for molding a multipolar anisotropic resin magnet.

[Prior Art] Conventionally, there have been roughly two methods for manufacturing a cylindrical or cylindrical resin magnet having four or more magnetic poles on the outer periphery by injection molding.

One is to injection mold a radially oriented molded product by flowing magnetic flux radially from the center within the cavity, and then add a magnetization process using a magnetizing member and a magnetization power supply to obtain a multipolar magnetized product. It is. The other method is to incorporate a large number of excitation coils into the mold and form the desired number of magnetic poles around the outer circumference of the cavity.
This method performs multipolar magnetization at the same time as injection molding.

[Problems to be solved by the invention] In the conventional method described above in which multipolar magnetization is performed after injection molding of a radially oriented molded product, a magnetized member,
A power supply for magnetization is required, and furthermore, this magnetization process significantly reduces productivity. Further, in the method of incorporating the excitation coil into the mold, the mold becomes complicated and expensive, and a power supply device and a control device for the excitation coil are required. Furthermore, since this excitation coil requires a considerable amount of space within the mold, there is a problem in that only four to six poles can be magnetized at most.

The present invention was devised in view of the above-mentioned problems of the conventional technology, and aims to provide an injection molding machine capable of molding a multipolar anisotropic resin magnet with six or more poles in one step. .

[Means for Solving the Problems] The injection molding machine for molding multipolar anisotropic resin magnets of the present invention is provided with excitation coils on each of the fixed platen and the movable platen of the injection molding machine, and the excitation coils on the fixed platen and the movable platen. The mold to be mounted has an even number of ferromagnetic steel yokes buried at intervals in the circumferential direction on one side of a non-magnetic steel member fixed to a ferromagnetic steel plate, and a cavity in the center. one mold in which a ferromagnetic steel passage member for magnetically connecting the even number of ferromagnetic steel yokes and the ferromagnetic steel plate is embedded; A ferromagnetic steel member that magnetically connects the ferromagnetic steel plate to a ferromagnetic steel yoke to which the ferromagnetic steel passage member is not connected to a nonmagnetic steel member fixed to the ferromagnetic steel plate. and the other mold in which the molding passage member is embedded.

[Function] In the injection molding machine of the present invention, when the excitation coil generates a magnetic field, the magnetic field is transmitted to the fixed plate, the ferromagnetic steel plate, the ferromagnetic steel passage member, the ferromagnetic steel yoke, and the cavity. When the magnetic field flows through a magnetic circuit formed by a ferromagnetic steel yoke, a ferromagnetic steel passage member, a ferromagnetic steel plate, and a movable platen, and passes through the cavity, an inlet and an outlet of the magnetic field are generated on the outer periphery of the cavity. At this time, if the inlet is a north pole, the outlet becomes a south pole, and the north and south poles can be alternately oriented around the outer circumference of the cavity.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an injection molding machine for molding a multipolar anisotropic resin magnet according to the present invention, and FIG.
A cross-sectional view taken along line A, FIG. 3 is a diagram showing the path of the magnetic field flowing through the ferromagnetic steel yokes 222 to 225 forming the cylindrical cavity 200, and FIG. 4 is a diagram showing the path of the magnetic field inside the cylindrical cavity 200. be.

As shown in FIG. 1, the magnetic field injection molding machine of the present invention includes a mold clamping device 1, a movable platen 11 equipped with an excitation coil 14 for applying a magnetic field to the mold, and a stationary platen equipped with an excitation coil 15. It consists of a board 12 and tie bars 13, which are made of ferromagnetic material. Then, the movable platen 11 slides on the tie bar 13 by a known driving means (not shown),
It is configured to perform mold clamping or mold opening. Further, the mold of this embodiment is for four-pole magnetization, and is composed of a fixed mold 2 and a movable mold 3. The movable mold 3 includes a non-magnetic steel plate member 22 having one side fixed on a plate-shaped ferromagnetic steel plate 21, and as shown in FIG. A hole 230 is formed, and the mounting hole 230
has a cylindrical cavity 20 having the configuration described below.
each ferromagnetic steel yoke 222 to form a
223, 224, 225 and each non-magnetic steel yoke 2
26, 227, 228, and 229 are fitted and fixed. As shown in FIGS. 2 and 3, the cylindrical cavity 200 has four wedge-shaped ferromagnetic steel yokes 222, 223, 22.
The yokes 222, 225 made of ferromagnetic steel are fitted into the mounting hole 230 in a cross shape and fixed.
A nonmagnetic steel yoke 22 having the same shape as the space is provided in each space divided by 3, 224, and 225.
6,227,228,229 is inserted and fixed,
It is formed by a space formed in the center of these parts. Further, ferromagnetic steel passage members 220 and 221 are arranged in the non-magnetic steel member 22 to magnetically connect the heads of the ferromagnetic steel yokes 222 and 225 and the ferromagnetic steel plate 21. ing.
The fixed mold 2 includes a non-magnetic steel member 23 having one side fixed on a plate-shaped ferromagnetic steel plate 24,
The non-magnetic steel member 23 includes a ferromagnetic steel passage member that magnetically connects the heads of the ferromagnetic steel yokes 223, 224 and the ferromagnetic steel plate 24 when the mold is clamped. Mounting holes 232, 231 are provided, and the ferromagnetic steel passage members 232, 231 are disposed therein.

With the above configuration, this injection molding machine forms a magnetic circuit between the mold clamping device 1 and the mold.

Next, the magnetic field path of this embodiment will be explained.

When the movable side and fixed side excitation coils 14 and 15 are energized in the same direction, the generated magnetic field is
→ Fixed mold 2 → Movable mold 3 → Movable platen 11 → Tie bar 13 → Fixed platen 12. In the fixed mold 2 and the movable mold 3, the magnetic field passing through the ferromagnetic steel plate 24 is
As shown in the figure, it reaches ferromagnetic steel yokes 224 and 223 via ferromagnetic steel passage members 231 and 232 of the nonmagnetic steel member 23. Subsequently, it passes through the cylindrical cavity 200, passes through the ferromagnetic steel yokes 222, 225 of the non-magnetic steel member 22, and the ferromagnetic steel passage members 220, 221, and reaches the ferromagnetic steel plate 21. As a result, the magnetic field passes through the path shown in FIG. 4 within the cylindrical cavity 200, and four magnetic field entrances and four exits are formed.
At this time, four magnetic poles are formed around the outer periphery of the cylindrical cavity 200, with the inlet being the north pole and the outlet being the south pole.

In addition, in this embodiment, non-magnetic steel yokes 226, 227, 228, 229 forming the cavity are used.
Although the and non-magnetic steel member 22 are made into separate bodies, it is also possible to process them as one piece. Furthermore, when attaching the fixed mold 2 and the movable mold 3 to the mold clamping device 1, contrary to this embodiment, the fixed mold 2 is placed on the movable platen 11 side, and the movable mold 3 is placed on the fixed platen 11 side.
Even when attached to the side, the same magnetic field as above is generated.

[Effect of the invention] Since the invention of the present application is configured as described above,
This has the following effects.

The cylindrical cavity is constructed by alternately arranging ferromagnetic steel yokes and non-magnetic steel yokes, and by forming a magnetic field path between the mold clamping device and the mold, N and S poles are created on the outer periphery of the cylindrical cavity. can be oriented alternately. Therefore, if molten resin containing anisotropic magnetic powder is injected into the cavity, magnetic orientation and magnetization will occur at the same time, and if the molded product is removed after cooling, a multipolar magnetized resin magnet will be obtained. . Also,
By using the mold of this invention, there is no need for a post-magnetization process or an excitation coil inside the mold, and by increasing the number of ferromagnetic steel yokes that make up the cavity, it is easy to magnetize four or more poles. Become something. Furthermore, the non-magnetic steel yoke that forms the cavity together with the ferromagnetic steel yoke fixed to the non-magnetic steel member of one of the molds is fixed separately from the non-magnetic steel member. Machining of non-magnetic steel members of molds becomes easier.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an injection molding machine for molding a multipolar anisotropic resin magnet according to the present invention, and FIG.
A cross-sectional view taken along line A, FIG. 3 is a diagram showing the path of the magnetic field flowing through the ferromagnetic steel yokes 222 to 225 forming the cylindrical cavity 200, and FIG. 4 is a diagram showing the path of the magnetic field inside the cylindrical cavity 200. be. 1...mold clamping device, 2...fixed mold, 3...movable mold, 11...movable platen, 12...fixed platen, 13...
...Tie bar, 14...Movable side excitation coil, 15...
...Fixed side excitation coil, 21, 24...Ferromagnetic steel plate, 22, 23...Nonmagnetic steel member, 20
0...Cylindrical cavity, 220, 221, 23
1,232...Ferromagnetic steel passage member, 222-2
25...Ferromagnetic steel yoke, 226-229...
Non-magnetic steel yoke.

Claims (1)

[Claims for Utility Model Registration] Excitation coils 15 and 14 are provided on the fixed platen 12 and the movable platen 11 of the injection molding machine, respectively, and the mold attached to the fixed platen 12 and the movable platen 11 has a ferromagnetic steel plate 21. An even number of ferromagnetic steel yokes 222, 223, 224, 225 are buried at intervals in the circumferential direction on one side of the non-magnetic steel member 22 fixed to the non-magnetic steel member 22.
0 and magnetically connects the even number of ferromagnetic steel yokes 222, 225 and the ferromagnetic steel plate 21.
20 and 221 are embedded, and a ferromagnetic steel plate 24 that pairs with the above mold.
The ferromagnetic steel yokes 223, 224 to which the ferromagnetic steel passage members 220, 221 are not connected and the ferromagnetic steel plate 24 are magnetically connected to the non-magnetic steel member 23 fixed to the ferromagnetic steel plate 24. An injection molding machine for molding a multipolar anisotropic resin magnet, which is constructed from the other mold in which ferromagnetic steel passage members 232 and 231 are embedded.