JPH0410606A - Ring magnet molding apparatus and ring magnet manufactured using same - Google Patents

Abstract

PURPOSE:To mold a ring magnet whose inner diameter is machined by right- angle punch by putting magnetic powder having appropriate grain size, a binder and the like in a dice and by pressing them by upper and lower punches with an inner-diameter machining slide die sandwiched therebetween. CONSTITUTION:A combination of upper punch 22 and a lower punch 33, both of which are made of non-magnetic ultra steel are arranged in a die 11 made of magnetic super steel, and an inner-diameter machining slide die 7 is arranged from side in the center portion thereof. Both the upper punch 22 and the lower punch 33 have top ends in the shape of a half moon via the slide die 7. Electromagnets 8, 8 for forming a magnetic field are arranged in a die 11 in such a way that the inner-diameter machining slide die 7 is positioned in the center of the magnetic field and that a magnetic field intersecting at right angles with the upper punch 22 and the lower punch 33 is generated. A sintered magnetic material 9 formed from rare-earth magnetic powder formed into an appropriate grain size, a binder or the like is put into the die 11 and magnetized. Thus, a non-sintered substance 10 of a ring magnet is obtained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to an anisotropic ring-shaped magnet forming device, and is capable of forming an anisotropic ring-shaped magnet by obtaining magnetic anisotropy perpendicular to the pressing direction. , relates to a ring-shaped magnet forming device that can achieve high performance and a ring-shaped magnet manufactured by the same device.

(Prior art) Conventional samarium-cobalt and neodymium-iron
Ring-shaped magnets made of rare earth elements such as boron are used in axial gap type motors, and the molding equipment therefor has a structure similar to that used to mold oil-impregnated bearings. That is, as shown in FIG. 5, a die 1 made of super steel made of a non-magnetic material that determines the outer diameter, an upper punch 2 made of magnetic super steel,
Similarly, the lower punch 3 is fitted with silk, a mandrel 4 that determines the inner diameter is placed at the tip of the upper punch 2, and a hole 3a into which the mandrel 4 fits is provided in the lower punch 3, so that a magnetic field is generated in the direction of movement of these punches 2.3. An external magnet 5.6 is arranged so as to be added. In such a device, the pressing direction P and the magnetic field direction M match, and a ring-shaped magnet, which is usually called parallel striking, can be produced.

(Problem to be Solved by the Invention) However, the ring-shaped magnet manufactured by such a device cannot fully demonstrate its inherent performance.

This is because the thinner the material is, the more the magnetic anisotropy is distorted due to internal stress during pressing. In order to alleviate this deterioration in performance during pressing, methods have been taken to form the block with a fairly thick cutter and slice the block to obtain thin ring-shaped magnets, but there is a limit to the improvement in performance. .

In order to solve the above-mentioned drawbacks, we purposely divided the ring-shaped magnet into four parts (magnetic number) to make the pressing direction and the magnetic field direction perpendicular to achieve the original performance. In other words, as shown in Figure 6. A structure is being considered in which the block is formed into a fan-shaped cross section and then thinly sliced. In the figure, M is the magnetic field direction and P is the press direction.

In this way, it is possible to increase the power by about 10% for parallel hitting. However, the cost increases significantly because four separate magnets are manufactured, and when these four magnets are used in a motor, the number of machining steps such as fixing them increases significantly, resulting in an expensive motor. Put it away.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a magnetic forming apparatus comprising an upper punch, a lower punch, and a die combined with these punches, in which the die is movable in a direction perpendicular to the punch. A slide mold for inner diameter processing is arranged, and an electromagnet for magnetic field shaping is arranged to apply a magnetic field in the moving direction of the slide mold. Desirably, the die is made of a magnetic material and at least one part of the slide mold is arranged. The part is made of a non-magnetic material or a weakly magnetic material. A ring-shaped magnet was manufactured using the above molding apparatus.

(Function) According to the above-mentioned forming apparatus, by putting magnetic powder and binder etc. of appropriate particle size into the die, and pressing with the upper punch and lower punch with the slide mold for inner diameter processing sandwiched therein,
A ring-shaped magnet with a machined inner diameter can be formed by punching at a right angle.

(Example) Fig. 1 is a schematic cross-sectional view of the main part of the ring-shaped magnet forming device of the present invention, viewed from the front and cut at the center, and Fig. 2 is a schematic cross-sectional view cut at the center when viewed from the direction perpendicular to the same cross-section. It is a sectional view of the main part. That is, the die 11 made of magnetic super steel
, an upper punch 22 made of non-magnetic super steel and a lower punch 33 are combined, and a slide die 7 for inner diameter machining is arranged laterally in the center. They each have half-moon-shaped tips through the mold 7, and slight chamfers a and b are formed at both ends to prevent breakage. The electromagnet 8.8 for magnetic field shaping is arranged on the die 11 so that the slide die 7 for inner diameter machining is located at the center of the magnetic field and a magnetic field perpendicular to the upper punch 22 and lower punch 33 is generated.

Now, when a sintered magnetic material 9 made of rare earth magnetic powder, a binder, etc. having an appropriate particle size is placed in the die 11 and magnetized, a ring-shaped magnet green body 10 as shown in FIG. 3 is obtained. Thereafter, the ring-shaped magnet R shown in FIG. 4 is obtained by performing necessary processing steps such as sintering, grinding the outer periphery, and slicing thinly if necessary.

[Effects of the Invention] Since the ring-shaped magnet forming apparatus of the present invention is configured as described above, it is possible to perform transverse magnetic field forming even though it is ring-shaped (with an inner diameter), and it is possible to perform transverse magnetic field forming to achieve its original performance. A molded ring-shaped magnet is obtained, and as a result, the performance of a motor using this ring-shaped magnet can be improved.Moreover, since it is in the form of one connected ring, it does not lead to an increase in the number of bonding steps, etc. It is also advantageous in terms of cost.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view of the main part of the ring-shaped magnet forming apparatus of the present invention, Fig. 2 is a schematic sectional view of the main part taken in the direction perpendicular to Fig. 1, and Fig. 3 is a ring-shaped magnet formed by the same apparatus. FIG. 4 is a perspective view of a completed ring-shaped magnet, FIG. 5 is a schematic cross-sectional view of a conventional ring-shaped magnet forming device, and FIG. 6 is a conventional molding device. FIG. 3 is a perspective view of a split magnet piece formed by transverse magnetic field forming. 11 is a die 22 is an upper punch 33 is a lower bunch 7 is a slide F type 8 is an electromagnet for magnetic field forming patent applicant Tokyo Parts Kogyo Co., Ltd. α)

Claims (3)

[Claims] (1) In a magnetic forming device consisting of an upper punch, a lower punch, and a die combined with these punches, the die is provided with a slide mold for inner diameter machining that is movable in a direction perpendicular to the punch, and the direction of movement of the slide mold is A ring-shaped magnet forming device with magnetic field forming electromagnets arranged to apply a magnetic field to the area. (2) The ring-shaped magnet molding apparatus according to claim 1, wherein the die is made of a magnetic material, and at least a part of the slide die is made of a non-magnetic material or a weakly magnetic material. (3) A ring-shaped magnet manufactured by the molding apparatus according to claim 1 or 2 above.