JPS5919412Y2 - Molding mold for ring-shaped resin magnet - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a molding die for a ring-shaped resin magnet in which a cross-wire material of a magnetic material and a resin material is molded in a magnetic field so as to be magnetically oriented.

Generally, it is already known that a material made by kneading ferrite powder with strong magnetic anisotropy and thermoplastic plastic is molded in a magnetic field to obtain a magnetically oriented molded product. There are many examples of radial orientation.

The principle is to generate lines of magnetic force from the mold member that forms the inner diameter of the ring to the mold member that forms the outer diameter, and then fill the cavity with resin containing ferrite powder.

Due to this principle, the following problems occur in the general multi-cavity method.

In other words, normally multiple cavities are placed side by side on the mold parting surface, but the directions of the magnetic lines of force cancel each other out in the vicinity of the cavities, and the magnetic field becomes weak in some areas. There was a drawback that the degree of orientation was non-uniform.

That is, FIG. 1 is a diagram showing an example of this, and since the lines of magnetic force indicated by arrows face each other in the adjacent portions of core 1 and core 2, the degree of orientation in the portions of molded products 3 and 4 shown in perspective is low. There was a drawback.

In addition, if the molded products 3 and 4 are sufficiently spaced, the above-mentioned drawbacks will be alleviated, but the size of the mold will increase and the molding machine that can be used will also be larger, resulting in lower cost and workability. It also had the disadvantage of being inconvenient.

The present invention eliminates these conventional drawbacks and provides a multi-cavity mold that maintains a uniform degree of orientation in the circumferential direction.

That is, a plurality of cavities are arranged so as to be stacked on a core axis, so that there is only one core axis.

2 and 3 show an embodiment of the present invention, in which:
The movable mounting plate 25 fixes the bottom plate 26, and the magnetic bottom plate 2
6 supports a magnetic core 27 and a side plate 28 made of magnetic material.

The coil 29 is provided around the magnetic core 27 and surrounded by the side plate 28.

Non-magnetic plate 30 and non-magnetic third template 3
1 is fixed to the side plate 28, and has a protruding plate 32 made of non-magnetic material.
is incorporated in a slidable manner with respect to the magnetic core 27.

Also, a second template plate 33.33' made of magnetic material, a plate 34.34' made of non-magnetic material, and a second template plate 35.35' made of magnetic material.
are each fixed separately, and each is separately fixed to the third template 31.
It can be slid on the contact surface with the pin hole and has a pin hole.

Angular pin 36 provided in the pin hole and the fixed side
．． Holes forming cavities 37 and 38 facing the magnetic core 27 are provided in the first template 33, 33' and the second template 35, 35', which together with 36' constitute a plate opening/closing means, The plates 34 and 34' are provided with semicircular recesses and grooves 39 that slidably fit into the magnetic core 27.

The first template 33 is in contact with the side plate 28 and the second template 35 at its outer periphery.

Fixed side mounting plate 40 made of non-magnetic material and fourth template plate 4 made of non-magnetic material
1 is fixed and supports an angular pin 36°36'.

A runner groove 42 is provided in the fourth template 41 so as to connect to the cavity 38, and a sprue hole 43 connected to the runner groove 42 is provided passing through the mounting plate 40 and the fourth template 41. ing.

In the mold thus constructed, a magnetic path is formed as shown by the arrow in the figure by passing an electric current through the coil 29.

After that, the cavities 38 and 37 are filled by press-fitting a mixed wire material of molten magnetic material and resin material through the sprue hole 43, and the magnetic powder in the filled resin is oriented in the direction of the magnetic field lines. .

After the resin filled in the mold is cooled and solidified, the mold is opened as shown in FIG. - Guided by the pins 36, 36', they slide in the directions of the arrows as the mold opens, and stop sliding when the angular pins 36, 36' separate from the second mold plates 35 and 35.

The ring 44 can be released from the mold by sliding the two plates 34 and 34', and by further opening the mold, the protruding plate 32 engages with the fixed side, and by continuing to open the mold, the protruding plate 32 It slides together with the magnetic core 27 and moves relatively to the fixed side.

At this time, the rings 44 and 45 are also removed from the magnetic core 27 in conjunction with the protruding plate 32.

In this way, a molded door is obtained in which the rings 44 and 45 are connected by the gate 46, the ring 45 is connected to the runner 47, and the runner 47 is connected to the sprue 48, as shown in FIG.

Here, the sprue 48 is connected to the sprue hole 43 in FIG. 4, the runner 47 is connected to the runner groove 42, and the ring 45
is the cavity 38, the ring 44 is the cavity 37,
The runners 46 correspond to the grooves 39, respectively.

The runner of the molded door shown in FIG. 4 can then be cut to obtain a ring-shaped magnet of the desired shape, which is then magnetized using suitable magnetization means.

Such a mold has the advantage that a general-purpose molding machine can be used.

FIG. 5 shows an example of application of the present invention, in which the magnetic core 49 is a core of different diameters having a large diameter part 50 and a small diameter part 51, and a template made of a magnetic material having holes forming cavities 52 and 53, respectively. 54 and 55 are provided, the first template 54 and the second template 5
A non-magnetic plate 56 is installed between the two.

The plate 56 is provided with a hole corresponding to the small diameter part 51 and is combined with the different diameter part of the magnetic core 49.

Such a mold has the advantage that molded doors with different ring diameters can be obtained at the same time.

Here, the crosstalk material between the magnetic material and the resin material is injected using a liner.

In the above embodiments, a mold with two molds is shown, but the present invention is not limited to this, and it goes without saying that it is possible to use molds with three or more molds.

As described above, according to the present invention, a plurality of cavities are provided in the axial direction of the core axis that constitutes the magnetic circuit, so that the degree of orientation in the circumferential direction of the ring-shaped resin magnet to be molded can be made uniform, and a large number of pieces can be produced. The practical value of this method is extremely great, as it is possible to construct a mold that is possible, and the size of the mold can be made to be approximately the same size as a single-cavity mold.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional mold, FIG. 2 is a sectional view showing an embodiment of the mold of the present invention, FIG. 3 is a diagram for explaining the opening operation of the mold, and FIG. The figure is a perspective view of a molded door formed by the same mold, and FIG. 5 is a sectional view of a main part showing another example of the configuration of the mold of the present invention. 5.25...Mounting plate, 6,26...Bottom plate, 7,27°49...Magnetic core, 8,28...
...Side plate, 9,29...Coil, 31...
...Third template, 33.33'...First template, 34°34'...Plate, 35.35'
...Second template, 36°36'...Angular bottle, 40...Mounting plate, 41...
... Fourth template, 37.38 ... Cavity, chi groove, 43 ... One hole for sprue. 42...Run

Claims (1)

[Scope of utility model registration request] a magnetic core made of a magnetic material with a coil arranged at one end and the other end forming the inner diameter of a ring-shaped resin magnet;
A first template and a second template made of a magnetic material are provided facing each other at a predetermined distance to form a cavity at one end of the magnetic core, and the first template and the second template side plates and a bottom plate made of a magnetic material that magnetically connect the magnetic core at least in the mold closed state; A pair of plates of non-magnetic material that partially define the cavity and can be divided in the radial direction of the magnetic core, and are provided on both sides of the first template and the second template, respectively, in contact with the other plate surface. A molding tool for a ring-shaped resin magnet, comprising third and fourth mold plates made of non-magnetic material, and a plate opening/closing means that opens at least the two plates in a direction perpendicular to the mold opening direction by a mold opening operation. Type.