JPS60220918A - Manufacture of permanent megnet - Google Patents

Abstract

PURPOSE:To obtain an anisotropic permanent magnet without decrasing the extrusion capacity by a method wherein, when the resin-bonded rare earth permanent magnet made of a mixture, wherein a thermoplastic resin has been used as a bonding material, is extrusion-molded, draw-out units which synchronize with the extrusion rate, are provided at the point of the molding metal mold of the extrusion molding device. CONSTITUTION:A mixture of 65vol% of magnet powder of a rare earth intermetallic compound, whose particle size is 2-80mum, and 35vol% of nylon, which is a thermoplastic resin, is thrown in a cylinder 2 built-in with a screw 4 through a hopper 1. The mixture is mixed by the screw 4 while being heated by heaters 3 provided on the outer periphery of the cylinder 2 at about 300 deg.C and is pushed out to a tapered barrel part 5 by the turning force of the screw 4. After that, the mixture is made to pass through a magnetic circuit part 6 combined with a molding die, is made to orientate by a magnetic field, and then is cooled in a cooling part 7. After this, the mixture is made to pass through a demagnetizing circuit 8 and is pushed out after being subjected to a demagnetization. Moreover, draw-out rollers 9 with the surfaces coated with rubber are provided on the rear stage of the circuit 8 in this extrustion molding device constituted in such a way and a desired extrusion molded product 10 is obtained by making the rotation of the rolllers 9 synchronize with the extrusion rate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing a thermoplastic resin bonded rare earth permanent magnet by extrusion molding.

[Prior art]

Conventionally, thermoplastic resin bonded rare earth magnets manufactured by extrusion molding are almost isotropic regardless of their shape, so the molded part is the Taber versile part, and the magnet body extruded only with the molding die is At ffJ, it was possible to extrude without encountering resistance.

However, recently magnetic anisotropy has been added. As anisotropic permanent magnets are now being extruded, a magnetic circuit section, a degaussing circuit section, a cooling section, etc. are added to the tapered barrel section and the side of the molding die, which increases the resistance of extrusion molding. However, there was a problem in that the extrusion capacity was reduced accordingly.

〔the purpose〕

The present invention is intended to solve these problems.
The purpose is to manufacture anisotropic extrusion-molded permanent magnets without reducing extrusion capacity by installing a pull-out device that synchronizes with the extrusion speed at the tip of the molded product extrusion port of the extrusion molding device and pulling out the molded product. The purpose is to provide a method.

〔overview〕

The method for producing a permanent magnet of the present invention uses a thermoplastic resin such as nylon 6, nylon 6-6, nylon 12, polyethylene, polypropylene, pps (bolyphelene sulfide), EVA (ethylene, vinyl acetate copolymer), etc. as a binder. For example, when manufacturing a permanent magnet using an alloy with a rare earth intermetallic compound composition consisting of Y and lantonide rare earth metals and transition metals, a magnet is installed at the tip of a tapered barrel to add magnetic anisotropy. A magnetic circuit section that applies a magnetic field to add magnetic anisotropy, a cooling section that cools and solidifies the molded product, and a demagnetization circuit that demagnetizes the remaining magnetism in the molded product are added to the die section. In a manufacturing method of extrusion molding using a medium extrusion device, the tip K of the extrusion molding port is pulled out by a roller or the like at a speed synchronized with the extrusion speed of the molded product to be extruded.
A drawing device is provided to draw out the magnetically anisotropic permanent magnet which is a molded product.

[Example 1] FIG. 1 shows an example of the method of the present invention. First of all, the rare earth magnet powder has a general formula of 5rn (ao6, 6710uo-
am×F60.22 “?’ 0.028) 8.311
A 2-17 rare earth metal compound consisting of the following was used. This alloy was made into magnetic powder with a particle size of 2 to 80 microns using a ball mill. To 65 volumes of the powder thus produced, a thermoplastic resin, Steelon 6, was added as a 35 volume binder. The ratio of magnet powder to resin is 40~
Although it is possible to capture the resin in the range where the remaining part is resin with 85 volume chips, if the amount of powder is increased, the Suff'I x-resistance at the time of crosstalk becomes large, so 65 volume chips were used. This mixture of powder and resin was charged from hopper 1 into an extrusion molding apparatus in a magnetic field. The charged mixture enters the cylinder 2 and is heated by the heater 3 to about 3
The material is heated to 00°C, kneaded by a screw 4, extruded into a taper pearl section 5 by its rotation, oriented by an orienting magnetic field when passing through a magnetic circuit section 6 that also serves as a molding die, and passed through a cooling section 7 in that state. The molded body is then cooled and the binder nylon 6 solidifies, but since there is residual magnetism from the orientation magnetic field, a reversal magnetic field is not applied in the opposite direction to the orientation magnetic field when passing through the next degaussing circuit 8. It is demagnetized and extruded out of the mold. By this method, a tape-shaped resin-bonded rare earth magnet having a width of 20 mm, a thickness of 0.5 mm, and a length of 1500 m and having magnetic anisotropy in the thickness direction was molded. This device has a pull-out roller 9 whose surface is made of rubber.
The molded product can be pulled out at a slightly faster speed than the installation speed by rotating it in the direction of the arrow, driven by a V-belt from a power unit with a transmission attached to a separately installed synchronous motor. Adjusted and installed it. Since the withdrawal speed can be varied by adjusting the transmission and can be synchronized with the extrusion speed, the following data was obtained while conducting experiments. The assumed extrusion speed was 12%/min for isotropic molding without magnetic circuits, cooling parts, etc., but when a device for making anisotropic magnets was installed, it was 9.8971/min. Yes, and when the device according to the method of the present invention is set, 10.9 ~
The molded product was in good condition with no slippage of the rollers and no scratches or wrinkles.

[Example 2] This example shows an example of extrusion of a cylindrical radially anisotropic permanent magnet. The magnet powder used was the same as that used in Example 1, and the magnetic circuit section, cooling section, and degaussing circuit section of the magnetic field extrusion molding apparatus shown in Fig. 1 were partially changed, and the powder was made into a cylindrical shape. The core for the game was placed in the center, and the winning dice were made into a round shape.

By the same method as in Example 1, the outer diameter is 2-2jI11 and the inner diameter is 20.
Ryucho obtained a 620 tm cylindrical radially anisotropic permanent magnet. A drawing device shown in FIG. 2 was attached to this extrusion molding device. As in Example 1, the pull-out roller can be rotated in the extrusion direction by a V-belt drive from a power unit using a separate synchronous motor and transmission, and its speed can be varied by the transmission and synchronized with the extrusion speed. In addition, by rotating the outer diameter frame in the direction of the arrow, the pull-out roller, which divides the circumference into three equal parts, moves back and forth to match the outer diameter dimension, and the roller shape also has a round groove. Moreover, the front and surface are made of rubber to prevent deformation of the extruded cylindrical magnet.

Comparing the extrusion speeds as in Example 1, the magnetic circuit section,
When molding isotropically with no cooling section etc., it is 105 V min, and when it is radial anisotropic, it is 8.1 m/min. When the drawing device according to the method of the present invention is attached, 95 ~ min is applied to the molded product. -IF- It was in good condition with no occurrence of wrinkles, etc.

〔effect〕

As described above, when the drawing device according to the present invention is attached to the tip of the molding die when molding a thermoplastic resin-bonded rare earth anisotropic magnet by extrusion molding in a magnetic field, the extrusion force is increased by the resistance during extrusion. Since the magnet is pulled out with a capacity sufficient to cover the falling amount, it has the effect of being able to be molded and manufactured at an extrusion speed that is approximately the same as or similar to that used when extruding isotropic permanent magnets. Furthermore, since the structure is synchronized with the extrusion speed, there is no wrinkles in the molded product and the quality is improved.

[Brief explanation of drawings]

FIG. 1 shows this embodiment, and FIG. 2 shows the structure of the drawer device of the present invention. 1. Hopper 2.. Cylinder 6.. Heater 4.. Screw 5.. Taber barrel 6.. Magnetic circuit section 7.. Cooling section 8.. Demagnetizing circuit section 9.. Pulling roller 10.. Extrusion molded product 11 ...Outer diameter frame or more Applicant Suwa Seikosha Co., Ltd. Agent Patent attorney Tsutomu Mogami

Claims (1)

[Claims] In a manufacturing method in which a resin-bonded rare earth permanent magnet using a thermoplastic resin as a binder is extruded using an extrusion molding device, a drawing device synchronized with the extrusion speed is provided at the tip of a mold of the extrusion molding device, and the permanent magnet is Bring it out! i-
A method for manufacturing permanent magnets with % characteristics.