JPS6331930Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic field generator for a plastic magnet injection molding machine.

When injection molding an anisotropic plastic magnet, it is necessary to apply a magnetic field during the molding process, and there are two methods for applying this magnetic field. That is, there are two methods: a method in which a coil for generating a magnetic field is built into a mold, and a method in which a coil is arranged around the outer periphery of a mold clamping device of an injection molding machine.

The method of incorporating the coil inside the 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 present invention was devised by focusing on the above-mentioned problems in the magnetic field generator of conventional plastic magnet injection molding machines. The purpose is to solve the above problems by providing a coil moving device that movably guides the coil, provides a return yoke on the outside of the coil, and moves the coil to the molding position or mold removal position and stops it. There is.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. 1 to 4 of the accompanying drawings showing embodiments thereof.

First, the configuration will be explained.

As shown in FIG. 1, a rectangular cylindrical coil is attached to a rectangular parallelepiped movable mounting plate 14, which is attached to a movable platen 12 guided by tie rods 11, through four slide guides 16. 18 (first coil) is supported. Slide guide 1
6 is of a type having a large number of rollers 20 arranged so that their axes are perpendicular to each other, and is arranged at each corner of the movable mounting plate 14. Thereby, the coil 18 is reliably supported with respect to the movable mounting plate 14 and can be easily moved in the axial direction. Note that the amount of movement of the slide guide 16 is half of the amount of movement of the coil 18. Return yokes 22 (first return yokes) having an L-shaped cross section are provided on the upper, lower, left, and right outer peripheral surfaces of the coil 18, respectively. Note that the short side end surface of the return yoke 22 is in contact with the movable mounting plate 14. One return yoke 22 among the four return yokes 22
(The upper return yoke 22 in Figure 1) has the following:
A screw feed mechanism 24 that is a moving device for the coil 18
(first coil moving device) is provided. The screw feed mechanism 24 includes a stud 26 fixed to the movable platen 12, a feed nut 28 having an internal thread that meshes with the stud 26 and has worm teeth on the outer periphery, and a worm 30 (second worm) that meshes with the worm teeth of the feed nut 28. (see figure). Therefore, by rotating the worm 30, the return yoke 22 and the coil 18 can be moved and stopped at a predetermined position. During molding, the return yoke 22 and coil 18
The end face on the right side in Figure 1 is the movable mounting plate 1.
4 is stopped at a molding position that coincides with the right end surface of the movable mold 32 in FIG. 1 (that is, the mating surface of the movable mold 32).

A fixed mold 38 is attached to a fixed mold mounting plate 36 of a fixed platen 34 so as to face the movable mold 32. On the outer periphery of the fixed mounting plate 36, members having exactly the same configuration as the coil 18, return yoke 22, etc. provided on the outer periphery of the movable mounting plate 14 are provided. Since they have exactly the same configuration (however, the orientation of the arrangement is different), the reference numerals for the parts on the fixed mounting plate 36 side and those on the movable mounting plate 14 side are the same as those on the movable mounting plate 14 side. Detailed explanation will be omitted by indicating with ''. Note that the fixed mounting plate 36 is attached to the injection nozzle 40.
It has a nozzle hole 42 for receiving the
The fixed mold 38 also has a sprue 44.

Next, the effect will be explained.

First, the movable platen 12, which had been moved to the left in FIG. 1 to take out the molded product, was moved to the right for the next molding, bringing the movable mold 32 and the fixed mold 38 into close contact. The state shown in FIG. 1 is reached. At this time, the mutually facing end surfaces of the coil 18 and the coil 18' and the mutually facing end surfaces of the return yoke 22 and the return yoke 22' also come into contact. In this state, molten resin is injected from the injection nozzle 40. The molten resin enters the mold through the sprue 44 and a molded product 46 is formed. When injecting molten resin, coil 18 and coil 1
A magnetic field is generated by passing a current through 8' in advance. The magnetic flux generated by coil 18 and coil 18' forms a closed loop as shown by the arrows in FIG. One loop is the return yoke 2
2. Movable mounting plate 14, movable type 32, fixed type 3
8, a loop passing through the fixed mounting plate 36, the return yoke 22' in order, and the other loop passing through the movable platen 12, the movable mounting plate 14, the movable mold 32, the fixed mold 38, the fixed mounting plate 36, the fixed This is a loop that passes through the board 34 and the tie rod 11 in order. This magnetic flux acts on the molded product 46 before solidification, and the magnetization direction of the magnetic powder in the molten resin becomes constant, and it solidifies as it is, so that an anisotropic plastic magnet molded product is obtained. When the molding is completed, the movable platen 12 moves to the left in FIG. 1, and the molded product 46 is taken out. Since the coil 18 also moves together with the movable mold 32, there is no need to specifically move only the coil 18 when taking out the molded product 46.

The movable mold 32 and fixed mold 38 are removed as follows. First, by rotating the feed nut 28, the return yoke 22 and the coil 18 are moved toward the movable platen 12, that is, to the mold attachment/detachment position where the movable mold is exposed. Similarly, the return yoke 22' and the coil 18' are also moved to the mold attachment/detachment position on the stationary platen 34 side. coil 18
and the coil 18' are respectively connected to the slide guide 16.
Since it is supported by the slide guide 16' and the slide guide 16', the above movement is performed smoothly. FIG. 3 shows a state in which the coils 18 and 18' are moved as described above. In this state, the movable type 3
2 and the fixed mold 38 with wires, for example, remove the mounting bolts 33 of the movable mold 32 and the mounting bolts 39 of the fixed mold 38, then move the movable platen 12 to the left in FIG. Fixed type 38
Lift it up and take it outside. When installing the mold, the steps can be performed in the reverse order. As mentioned above, the screw feeding mechanism 24 and the screw feeding mechanism 24' are used to move the coil 18 and the coil 18' when the mold is attached or detached. Note that the screw feeding mechanism 24 and the screw feeding mechanism 24' may be devices using hydraulic cylinders, air cylinders, or the like.

As mentioned above, in the magnetic field generator of the plastic magnet injection molding machine according to the present invention, since the coil is provided outside the mold, it is possible to use a mold with a general structure, and the molded product When taking out the coil, the coil moves in tandem with the movable mold, so there is no need for time to move the coil, resulting in high productivity. Furthermore, the mold can be easily attached and detached by simply moving the coil. Furthermore, since a closed loop is formed to prevent magnetic flux from leaking, sufficient magnetic flux efficiency can be obtained even if the coil is downsized and power consumption is reduced.
Furthermore, there is no need to use a magnetic material in the mold clamping device. Moreover, according to the present invention, an ordinary injection molding machine can be easily modified to become an injection molding machine for plastic magnets. Further, the coil etc. can be removed when unnecessary.

As explained above, according to the present invention, the first coil (coil 18 in the embodiment) is supported on the outer periphery of the movable mounting plate via the slide guide. It is movable between a molding position that surrounds the outer periphery of the movable mold attached to the mounting plate and a mold removal position that exposes the movable mold, and a first return yoke 22 is attached to the outside of the first coil. A first coil moving device (screw feeding mechanism 24) capable of moving and stopping the coil to the molding position or mold attachment/detachment position is provided, and a slide guide is provided around the outer periphery of the fixed mold mounting plate facing the movable mold mounting plate. By supporting the second coil 18' through the mold, the second coil moves between a molding position where it surrounds the outer periphery of the fixed mold attached to the fixed mold mounting plate and a mold removal position where the fixed mold is exposed. A second return yoke 22' is attached to the outside of the second coil, and a second coil moving device (screw feeding mechanism 24') capable of moving and stopping the second coil to the molding position or mold removal position is provided. During molding in which the movable mold and the fixed mold are in close contact with each other, the first coil and the second coil and the first return yoke and the second return yoke at the molding position are in close contact with each other, and the first coil and the second coil are in close contact with each other. Since the magnetic flux thus generated is arranged to form a closed loop, it is possible to obtain a magnetic field generating device for a plastic magnet injection molding machine with high productivity and little leakage of magnetic flux.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a magnetic field generator for a plastic magnet injection molding machine according to the present invention, FIG. 2 is a perspective view of a magnetic field generator for a plastic magnet injection molding machine according to the present invention, and FIG. FIG. 4 is a diagram showing a state in which the coil of the magnetic field generator of the magnetic injection molding machine has been moved, and is a view taken along the - line in FIG. 3. 11...Tie rod, 12...Movable plate, 14...
...Movable mounting plate, 16,16'...Slide guide, 18,18'...Coil, 20,20'...Roller, 22,22'...Return yoke, 24,
24'...screw feeding mechanism (coil moving device), 2
6, 26'... Stud, 28, 28'... Feed nut, 30, 30'... Worm, 32... Movable type, 34... Fixed plate, 36... Fixed type mounting plate, 3
8... Fixed type, 40... Injection nozzle, 42... Nozzle hole, 44... Sprue, 46... Molded product.

Claims (1)

[Scope of utility model registration request] By supporting the first coil against the outer periphery of the movable mold mounting plate via a slide guide, the first coil surrounds the outer periphery of the movable mold attached to the movable mold mounting plate, and the molding position and the movable mold are exposed. A first coil moving device that is movable between a mold attachment/detachment position and a mold attachment/detachment position, a first return yoke is attached to the outside of the first coil, and is capable of moving the first coil to a molding position or a mold attachment/detachment position and then stopped. and the second coil is attached to the fixed type mounting plate by supporting the second coil via a slide guide to the outer periphery of the fixed type mounting plate facing the movable type mounting plate. A second return yoke is attached to the outside of the second coil, and a second return yoke is attached to the outside of the second coil.
A second coil moving device capable of moving and stopping the second coil to a molding position or a mold attachment/detachment position is provided, and during molding in which the movable mold and the fixed mold are in close contact, the first coil and the second coil in the molding position, and a magnetic field generating device for a plastic magnet injection molding machine, in which the first return yoke and the second return yoke are in close contact with each other, and the magnetic fluxes generated by the first coil and the second coil form a closed loop.