JPS6135687B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing rubber magnets and magnetic rubber by mixing and molding magnets, rubber as a binder, and synthetic resin raw materials.

Conventional methods for producing rubber magnets include mixing magnet particles and binder raw materials and press-molding the mixture to form a strong bond between the magnet particles and the binder such as rubber. During press forming, a magnetic field is applied, and the magnetic particles are formed with their axes of easy magnetization aligned in the magnetic field. However, the working magnetic field is usually a steady static magnetic field, so even if a strong magnetic field is applied, the magnetization axis will not change. It was not easy to align them, and this was the reason why it was not possible to increase the magnetic properties.

The present invention is characterized in that the magnetic field is applied in a pulsed manner and the number of applied pulses is controlled to a predetermined number required for the extrusion unit length of the raw material.

To explain below, as the rubber and synthetic resin raw materials for the binder, for example, hypalon, phenol, epoxy, polyethylene, urea, natural rubber, SBR, neoprene, chloroprene, polybutadiene, silicone rubber, etc. are used. This binder raw material is preferably in the form of fine particles and can be easily mixed. In order to use it after pulverization, it is recommended to use an impact pulverizer or the like to cool the raw material at a low temperature and give it some stiffness before pulverizing it. Magnet materials include MnAl material, Sm ₁ Co ₅ series, Sm ₂ Co ₁₇ series, BaO.
Fe ₂ O ₃ based hard magnet materials, FeCrCo based, FeCuNi
semi-hard magnets, FeSiAl-based, permalloy-based, and other soft materials are used, and these magnet materials are used by producing fine powder or by grinding them into fine powder. The magnet material to be used is not limited to one type, but a mixture of hard magnets and soft materials, semi-hard magnets and soft materials, etc. can also be used.

The combined molding of the mixture of magnet powder and binder is carried out by the apparatus shown in the embodiment diagram. In the figure, a vibration (ultrasonic) punch 2 is fitted into a mold 1 to press the powder, and a die 3 at the tip molds and extrudes the powder into a desired shape. Reference numeral 4 denotes a magnetic field forming coil provided around the mold, which is excited by an impact power source 5 to form a pulsed magnetic field. 6 is a heating coil that applies high frequency heating to the molded body continuously extruded from the die 3 for vulcanization and polymerization; 7 is a high frequency power source. 9 is a vibrator that applies ultrasonic vibration to the punch 2.

The raw materials 8 filled in the mold 1 are blended in the required amount, and depending on the application of the product, a large amount of magnet powder is blended to make a rubber magnet or an elastic or flexible magnet, and a magnetic rubber or magnetic sheet is mixed. For applications such as rubber, a small amount of magnet or magnetic material powder is mixed with the rubber material.

Good results can be obtained by surface-treating the magnet powder by coating it with an adhesive or the like with good wettability in advance. In addition, appropriate amounts of additives such as a vulcanizing agent, a vulcanization accelerator, and a pigment are blended into the binder rubber and synthetic resin raw material. The magnet and binder, which have been blended in the required amount, are mixed in a mixer, and by pulverizing the binder and using it, it mixes well with the magnet particles and is uniformly mixed. The metered and filled mixture raw materials 8 are bonded and molded by the die 3 in the mold 1 under the pressure of the punch 2. The mixed magnetic powder is molded into a state in which the axis of easy magnetization is aligned by the pulsed magnetic field generated by the coil 4, and its magnetic properties are improved. The action of a pulsed magnetic field can produce a shockingly large magnetic field compared to a static magnetic field, and since the magnetic field changes rapidly and acts repeatedly in a pulsed manner, a strong magnetic driving force acts. The axes of easy magnetization of the magnet powder during molding are easily aligned, and the alignment efficiency is increased, so that the powder is molded with the axes of easy magnetization sufficiently aligned. In addition, as shown in the figure, the forming punch is pressed by vibration while applying ultrasonic vibrations, so the mixed magnet particles are pressed into a state where they can easily roll, etc., and the pulsed magnetic field acts on them, resulting in extremely high efficiency. The easy magnetization axes are aligned. Magnets formed in this way have significantly improved magnetic properties. Dice 3
The extruded molded product is sufficiently heated (crosslinked) and polymerized by heat treatment using the coil 6, resulting in a product that is firmly bonded as a whole. The bonded state of the molded product is achieved by uniformly filling and pressurizing the entire molded product using a vibrating press, molding it to a homogeneous density, and bonding it to a high bonding strength.

Next, to explain an example, as a magnet material
Sm ₂ Co ₁₇ series, i.e. Sm ₂ (Co, Fe, Cu, Zr) _17-5
Using fine powder of ~10μφ, it is approximately
92% and 8% phenol were added to this, and when they were mixed and bonded and molded, an impulse current was passed through the magnetic field forming coil to generate a pulsed magnetic field of 110 Koe, and the pulsed magnetic field was applied 10 times per 10mm length to form the material. , when extruded, the maximum energy product was about 5.6×10 ⁶ G.Oe.
Furthermore, when applying ultrasonic vibration of 28KHz and 40W to the punch, the maximum energy product was approximately 6.2×10 ⁶ G・Oe. When a conventional DC magnetic field was applied, the maximum energy product was 4.1×10 ⁶ G.Oe, and compared to this, it was found that the effects of the present invention using a pulsed magnetic field and ultrasonic pulse were remarkable. In addition, when applying a pulsed magnetic field to the raw material, the number of pulses applied per unit length of extrusion is set and controlled to an appropriate amount so that the required amount of magnetic field is applied per unit length of extrusion, so that extrusion is always carried out at the specified level. The process can be carried out in a magnetic field, the uniformity of the extruded product is improved, and it is possible to produce high-quality products with certain properties at a high yield.

As described above, according to the present invention, since a magnet with high magnetic properties can be easily obtained, it can be used as a magnet, a buffer magnet, or a shock absorbing magnet used in places where pressure or impact is applied, and also as a magnet with elasticity and flexibility. A magnet with excellent characteristics that is effective as a pressure-sensitive magnet, an elastic, flexible magnetic material, etc. can be easily obtained.

[Brief explanation of the drawing]

The figure is a configuration diagram of an embodiment of the present invention. 1 is a mold, 2 is a pressure punch, 3 is a press die, 4 is a magnetic field forming coil, 5 is an impact power source, 6 is a heating coil, 7 is a heating power source, 8 is a raw material, and 9 is a vibrator.

Claims (1)

[Claims] 1. A method for manufacturing a rubber magnet in which a raw material mixed with a binder of rubber or synthetic resin and powder particles of a magnet or magnetic material is filled into a mold, pressed, molded into a desired shape from a die at the tip, and extruded. A magnetic field generator is installed that applies a magnetic field in a pulsed manner to the raw materials inside.
A method for producing a rubber magnet, characterized in that extrusion is performed by controlling the number of pulses of the working magnetic field per unit length of extrusion of the raw material to a predetermined number.