JPH0428207A - Manufacturing method of resin magnet - Google Patents

Abstract

PURPOSE:To obtain the compression-molded body of resin magnet having excellent magnetic characteristics, and to improve the problem arising in operation by a method wherein a magnetic field is inverted at least once. CONSTITUTION:After a magnetic field has been inverted at least once in the state wherein the mixture of magnetic powder, consisting of neodium-iron-boron material obtained using a super-quenching method, and resin is injected or filled in a molding mold, the magnetic field is applied in the direction where it is finally oriented, and after pressure-molding the above-mentioned material, it is hardened using resin as a binder. Through the above-mentioned procedures, magnetic powder moves in the molding mold, and its magnetic characteristics are improved. Also, as the above-mentioned operation is conducted in the molding mold, the problem of having poor workability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a resin magnet with excellent magnetic properties.

Conventional technology Conventionally, in order to improve the magnetic properties of this type of resin magnet, after kneading with resin before molding, or after magnetizing the powder state before kneading with a magnetic field higher than the molding magnetic field, A manufacturing method that involves molding (for example, Japanese Patent Application Laid-Open No. 58-1.57)
1.1.8) is well known and the problem to be solved by the present invention. However, since the above-mentioned conventional method for manufacturing resin magnets requires a high magnetic field for magnetization before molding, 1fI magnetization is difficult. At this time, magnet powder is placed directly in the magnetic field generating coil to magnetize it, and then injected into a molding die to perform magnetic field forming. At this time, since the pre-magnetized magnet powder aggregates, there is a problem in that it is difficult to inject into the mold and the workability is poor.

The present invention is intended to solve the above problems, and aims to provide a method for manufacturing a resin magnet with excellent magnetic properties.

Means for Solving the Problems In order to achieve the above-mentioned objects, the present invention involves injecting a mixture of a resin and a magnet powder made of a neodymium-iron-boron material obtained by an ultra-quenching method into a molding die. In this method, a magnetic field is reversed at least once in the filled state, and then a magnetic field is applied in the direction in which the final orientation is desired, and after pressure molding, the resin is cured as a binder.

Effect As in the above configuration, when a mixture of magnet powder and resin is injected or filled into a mold, a magnetic field is applied at least
By rotating the magnet powder, the magnetic powder moves in the mold, improving the magnetic properties. Furthermore, since the process is carried out in a mold, the problem of poor workability seen in conventional manufacturing methods is also improved.

Example An embodiment of the present invention will be described below.

An example will be described in which neodymium-iron-boron-based anisotropic magnet powder produced by an ultra-quenching method is used as the magnet powder. In addition, in order to improve temperature characteristics, corrosion resistance, and magnetic characteristics, it is also possible to use magnet powder to which various elements are added or substituted.

Fatty acids, silane camping agents, various surfactants, etc. were used as dispersants, and epoxy resins were used as binder components.

As the curing agent, various amines and acid anhydrides can be used.

Magnet powder, dispersant, epoxy resin, and curing agent were mixed in the following mixing ratio.

Magnet powder 100 parts by weight Dispersant 0.8 parts by weight Epoxy resin 1.0 parts by weight Curing agent 1.0 parts by weight Next, the above composition was cross-dispersed for 30 minutes using a kneader to form a compound for resin magnets. I got it.

Next, this plastic magnet compound was placed in a mold, a magnetic field of 15 KOe was applied, and a sample was prepared under the following conditions.

Sample-1 No magnetic field reversal operation Sample - Reverse the magnetic field 21 times.

Sample - Reverse the magnetic field 32 times.

Sample - Reverse the magnetic field 43 times.

Each sample was prepared based on the above conditions, and cold compression molding was performed at 6 tons/ci. 10 molded bodies
A resin magnet was obtained by curing at 0°C for 11 hours.

The results of measuring the magnetic properties and orientation of the obtained resin magnet are shown in the following table.

On the surface, the orientation is Br (/ ) / (Br (/
) +Br(±)), and Br(1)
represents the residual magnetic flux density in the direction of the magnetic field, and Br (±) represents the residual magnetic flux density perpendicular to the magnetic field direction.

The reason why this hardening of the magnetic field reversal is remarkable is that the shape of the neodymium-iron-boron anisotropic magnet powder produced by supermorphism and cooling is not spherical, as shown in the enlarged view of Figure 1. , this is thought to be due to the distortion.

In this way, according to the two-layer embodiment, the magnetic field is reversed one or more times while the mold is filled with a mixture of neodymium iron-boron magnet powder and resin.
A resin magnet with excellent magnetic properties could be obtained.

Effects of the Invention As is clear from the above examples, the present invention has the effect that by reversing the magnetic field at least once, a compressed body of a resin magnet with excellent magnetic properties can be obtained. In addition, since a magnetic field is applied in the mold, it is possible to overcome the problems encountered with conventional manufacturing methods.

[Brief explanation of drawings]

FIG. 1 is an enlarged view showing the shape of magnet powder used as a raw material.

Claims (1)

[Claims] A mixture of magnet powder made of neodymium-iron-boron material obtained by ultra-quenching method and resin is injected or filled into a mold, and the magnetic field is reversed at least once and then the final A method for manufacturing resin magnets in which a magnetic field is applied in the desired direction to orient the magnets, and after pressure molding, the resin is hardened as a binder.