JPH0712009B2 - Plastic magnet injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a plastic magnet (heterogeneous resin magnet).
The present invention relates to an injection molding machine for manufacturing.

[Conventional technology]

Conventionally, as a plastic magnet injection molding machine equipped with an electromagnetic coil for applying a magnetic field, basically, as shown in FIG. 5, an electromagnetic coil 27 is arranged at a position surrounding the tie bar 12, and the electromagnetic coil 27 is used. , The magnetic flux flows through the movable platen 8, the molds 13, 5, and the fixed platen 1 as shown by the arrow in the figure, and goes out of the fixed platen 1 into the air and goes around the electromagnetic coil 27 and returns to the movable platen 8 again. An injection molding machine of the type that forms a magnetic path (see Japanese Patent Application Laid-Open No. 57-105327) or, as shown in FIG.
Mounted on the outer periphery of a yoke 30 surrounded by a tie bar 29, and by this electromagnetic coil 28, magnetic flux is generated by the movable platen 8, the yoke 30, the molds 13, 5, and the fixed platen 1 as shown by the arrow in the figure. An injection molding machine of the type that forms a magnetic path that returns to the movable platen 8 via the flow tie bar 29 is known.

[Problems to be solved by the invention]

However, in the former injection molding machine, since magnetic flux is emitted into the air around the coil, magnetic efficiency is poor. Further, since the electromagnetic coil 27 and the molds 5 and 13 are widely separated and the distance between the fixed platen 1, the movable platen 8 and the mold cavity 17 is long, the total length of the magnetic path is considerably long and the movable mold In 13, since the magnetic path is bent and narrowed down by the molded product release mechanisms 16 and 18, magnetic flux easily leaks, and the magnetic efficiency decreases. Since the electromagnetic coil 27 is retracted to the plasticizer 21 side in conjunction with the opening operation of the movable mold 13, it is difficult to connect the mold temperature control wiring, piping, etc. The mechanism is required, and the safety door surrounding the outside of the electromagnetic coil 27 has a special shape, which is inevitable.

Also, in the latter injection molding machine, since a closed magnetic circuit that uses the tie bar 29 as a return yoke is configured, it has the advantage of high magnetic efficiency, but on the other hand, in order to install the electromagnetic coil 28 inside the tie bar 29, the movable mold The movable platen 8 had to be made larger in combination with 13, and the movable platen 8 had to be machined to incorporate the coil, which inevitably resulted in high equipment costs.

The present invention is made to solve the problems of the conventional injection molding machine in which the air around the coil is part of the magnetic path, and the coil moving method is stopped to provide the mold temperature control wiring,
The purpose of the invention is to facilitate the connection of pipes and the like and to improve the magnetic efficiency.

[Means for solving problems]

The plastic magnet injection molding machine of the present invention comprises a tie bar made of a non-magnetic material, a movable platen, a fixed platen and a mold made of a magnetic material, and a magnetic field in which the air around the coil is part of a magnetic path. In a plastic magnet injection molding machine provided with an electromagnetic coil for application, an annular frame portion made of a non-magnetic material that forms a die mounting portion is provided on the surface of each of the movable platen and the fixed platen so as to project.
The tie bar is penetrated through these frame parts, and the electromagnetic coils are attached to the frame parts so as to be circumscribed to the frame parts, and a mold made of a magnetic material is attached to the mold attachment part. It is characterized in that a die made of non-magnetic material is attached.

〔Example〕

Hereinafter, the present invention will be described with reference to FIG. 1 for an embodiment in which a magnetic field in the mold opening / closing direction is generated in a mold cavity.

In the figure, 1 is a fixed platen made of a magnetic material.
An annular frame portion 4 made of a non-magnetic material that forms, for example, a die mounting portion 3 that is circular in a front view is provided on the surface of the.
On the fixed platen 1, the mold mounting portion 3 is fitted,
In addition, a mold 5 made of a magnetic material, which is externally stopped by a method not shown, and a mold 6 made of a non-magnetic material, which is mounted around the tip projection of the mold 5, are attached to the platen 1. Is circumscribed on the frame 4 and the electromagnetic coil 7 is attached to the frame 4
It is mounted and fixed so as to form the same surface 2 as the above.

Reference numeral 8 denotes a movable platen made of a magnetic material. On the surface of the platen 8, for example, an annular frame portion 11 made of a non-magnetic material that forms a mold mounting portion 10 that is circular in a front view is provided in a protruding manner. The movable platen 8 is attached to the frame portion 4, by a mold clamping device (not shown).
It is possible to move forward and backward with respect to the fixed platen 1 along a tie bar 12 made of a non-magnetic material that penetrates through the platen 11. The platen 8 is fitted into the mold mounting portion 10 and is externally attached by a method not shown. Mold 13 made of stopped magnetic material and this mold
A mold 14 made of a non-magnetic material is attached around the tip protrusion of 13 and an electromagnetic coil 15 circumscribing the frame 11 forms the same surface 9 as the frame 11 on the platen 8. It is attached and fixed so that 16 is an ejector pin, one end of which faces the inside of the mold capacity 17 and the movable mold 13
Movably inserted into the ejector plate and the other end
They are connected by 18, and can be ejected by an ejector cylinder 19 via an ejector rod 20.

Reference numeral 21 denotes a plasticizer, which is capable of injecting and filling a kneaded material of a ferromagnetic powder and a molten resin into a mold capacity 17 through a resin passage 22 of a sprue runner gate.

[Work]

When the electromagnetic coils 7 and 15 are energized so that magnetic fields in the same direction are generated, the magnetic flux is moved to the movable platen 8 as shown by the arrow in FIG.
A closed magnetic circuit that flows through the molds 13 and 5 and the fixed platen 1, flows out from the fixed platen 1 into the air, goes around the outside of the electromagnetic coils 7 and 15 and returns to the movable platen 8 is formed. Because of this, the mold cavity
A magnetic field of magnetic flux φ along the mold opening / closing direction is applied to 17.

By the way, since the molds 5 and 13 are fitted and attached to the mold mounting parts 3 and 10 provided on the fixed side and the movable side, respectively, and are arranged at the position surrounded by the electromagnetic coils 7 and 15, the magnetic path Is shortened by that much, and the narrowing of the magnetic path by the molded product release mechanisms 16 and 18 is reduced, and moreover, it is fixed from the movable platen 8 by the nonmagnetic material frames 4 and 11 inscribed in the electromagnetic coils 7 and 15. Since the leakage of the magnetic flux to the platen 1 is reduced, the magnetic field applied to the mold cavity 17 is strong.

On the other hand, since the kneaded material of the ferromagnetic powder and the molten resin is injected and filled in the mold cavity 17 by the plasticizing device 21, each particle of the ferromagnetic powder is crystallized by the magnetic field to facilitate the magnetization. Oriented so that the directions are substantially parallel to the magnetic flux,
The molded product is cooled while maintaining its position. The molded product is opened after solidification, and each operation of discharging the molded product is sequentially performed, and the molded product is discharged from the molds 13 and 14 by the ejector pin 16.

When exchanging the molds 5, 6 and 13, 14, the mold platen 1 of the fixed platen 1 and the mold platen 10 of the movable platen 8 can be attached / detached, and the fixed platen 1 and the movable platen 8 can be inserted. The mold can be easily replaced as a holder. In addition, it is cheap and can be delivered in a short delivery time because the mold can be made only by inserting the mold.

An example in which the fixed platen 1 and the movable platen 8 are extended to the side surface portions of the electromagnetic coils 7 and 15 has been described. However, as shown in FIG. 1. Even if the movable platen 8 is extended and the coil covers 1a and 8a made of a magnetic material that surround the coils 7 and 15 are formed, the same effect can be obtained.

Next, the present invention will be described with reference to FIGS. 3 and 4 for an embodiment in which a magnetic field in a direction perpendicular to the mold opening / closing direction is generated in a mold cavity. In the figure, the same parts as those of the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

Reference numeral 23 in the drawing denotes a mold made of a magnetic material, which is mounted on the mold 6. This mold 23 is sandwiched between molds 6 and 14 and mold 13
And a ring-shaped mold cavity 24 is formed from these molds 6, 13, 14, 23.

Reference numeral 25 denotes a radial yoke made of a magnetic material, which is formed to have substantially the same thickness as the fixed-side die 23, and a circular opening 26 is provided at a substantially central portion of the yoke 25. This radial york
25 is mounted and fixed on the tie bar 12 between the fixed platen 1 and the movable platen 8, and is arranged around the fixed side mold 23 with a minute gap g.

[Action]

When the electromagnetic coils 7 and 15 are energized so that magnetic fields in the opposite directions are generated, the stationary platen 1 and the mold 5 as shown by the arrows in FIG.
After the magnetic flux flows through the movable platen 8 and the mold 13 in opposite directions, both magnetic fluxes change their direction by 90 ° at the tip of the movable mold 13 that constitutes the mold cavity 24, and the fixed mold 23, the radial York 2
Flows in the same direction as 5, and splits around the outer circumference of the radial yoke 25, returns around the outside of the electromagnetic coils 7 and 15 to the fixed platen 1 and the movable platen 8 to form respective closed magnetic paths. Therefore, the magnetic flux φ along the mold opening / closing direction and the direction perpendicular to the mold cavity 24 is
Since the magnetic field is applied, the magnetic field causes each particle of the ferromagnetic material in the filling material in the mold cavity 24 to be oriented so that the crystal axis direction of easy magnetization is radially aligned with the magnetic flux,
The molded product is solidified while maintaining its position. This molded product is used as a rotor of a motor after being magnetized into multiple poles by a magnetizer, for example.

〔The invention's effect〕

As described above, according to the present invention, the molds are detachably mounted in the mold mounting portions provided on the surfaces of the fixed platen and the movable platen via the frame part made of the non-magnetic material, and these molds are Since the magnetic path is arranged at a position surrounded by the electromagnetic coils that are circumscribed on the frame portion, the total length of the magnetic path is shortened by that much, and the narrowing down of the magnetic path by the molded product release mechanism is reduced. The frame portion made of a non-magnetic material inscribed in reduces the leakage of magnetic flux in the magnetic path from the movable platen to the fixed platen. Therefore, the magnetic efficiency is improved, and in combination with the combined use of the nesting method, it is possible to apply a uniform and strong magnetic field to each mold cavity with high power efficiency, and the running cost can be reduced.

In addition, the fixed platen and the movable platen can be used as an insert holder to easily replace the mold, and the mold can be manufactured only by inserting the mold, which is cheap and can be performed with a short delivery time.

Further, since the electromagnetic coils are mounted on the fixed platen side and the movable platen side respectively, the conventional coil interlocking movement mechanism is not required, and the mold temperature adjustment wiring, the piping, etc. can be easily connected.

[Brief description of drawings]

FIG. 1 is a plan sectional view showing a first embodiment of the present invention, and FIG. 2 is a plan sectional view showing a second embodiment obtained by partially modifying the same embodiment.
3 and 4 are plan sectional views showing a third embodiment of the present invention, I
Sectional views taken along the line V, FIG. 5, and FIG. 6 are plan sectional views showing a conventional example. 1 …… Fixed platen, 3,10 …… Mold mounting part, 5,6,23 ……
Fixed side mold, 7,15 …… electromagnetic coil, 8 …… movable platen, 12 …… tie bar, 13,14 …… movable side mold, 17,24 ……
Mold cavity, 25 …… radial yoke, 26 …… opening.

Claims (1)

[Claims] 1. An electromagnetic coil for applying a magnetic field, wherein the tie bar is made of a non-magnetic material, and the movable platen, the fixed platen and the die are made of a magnetic material, and the air around the coil is part of a magnetic path. In the plastic magnet injection molding machine provided with, the movable platen, an annular frame portion made of a non-magnetic material forming a mold mounting portion is provided on each surface of the fixed platen,
The tie bar is penetrated through these frame parts, and the electromagnetic coils are attached to the frame parts so as to be circumscribed to the frame parts, and a mold made of a magnetic material is attached to the mold attachment part. A plastic magnet injection molding machine, which is equipped with a mold made of non-magnetic material.