JPS5856401A - Production of sintered magnet - Google Patents

Abstract

PURPOSE:To achieve assembly work efficiently in coupling a plurality of magnets with a mark clearly indicating the direction of the magnetic field by a method wherein grooves or projections used to determine the direction of the magnetic field are made in the end surfaces of moldings formed of powder and the moldings are sintered, before being magnetized. CONSTITUTION:Two magnets 1', 1' are concentrically coupled together and grooves 7, 7 are positioned in the same direction, so that their positions are made to correspond to each other. The magnets 1' and 1' are positioned in such a manner that each of the directions of the magnetic fields coincides with the other, before being coupled together. The magnets 1', 1' are arranged in a yoke ring 8 of a micromotor by inserting them therein. If position-synchronizing grooves 8a are made in an end surface of the yoke ring 8, the magnets 1', 1' will be capable of being arranged in the yoke ring 8 readily and correctly in a preset direction by making the position of the groove 7 of the magnet 1' conform to that of the groove 8a.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a columnar or annular sintered magnet.

In a method for manufacturing a sintered magnet having a cylindrical shape, for example, with a magnetic field direction in the radial direction, a transverse magnetic field (orthogonal magnetic field) molding method is generally used to mold a powder compact. This figure shows the transverse magnetic field forming of the 18th machine. In the figure, 1 is a cylindrical powder compact, and 2 is the mold frame of the press machine for compacting it. Core J, Upper Δ Anchi 4 and Lower/4
The magnet 5 is arranged between excitation coils 6 and 60 for forming this metal magnetic field. And excitation;
The powder is formed in a magnetic field along the radial direction (horizontal direction) of the powder compact 1 by the coil 6.6, and the powder is processed in this magnetic field by the upper Δinch 4 and the lower Δinch 5 to form a powder compact. 1 as I
lt shape. In order to manufacture a sintered magnet, the powder compact 1 is sintered, and during this sintering, the magnetic field of the powder compact %J is demagnetized. ), a magnetic field having nine magnetic field directions along the radial direction is applied to the sintered body *a.

For example, when manufacturing a thin-walled or long cylindrical sintered magnet used in a field magnet for a micromotor, it is possible to use a press machine to mold the whole powder into a one-piece powder compact. Since this is difficult, the entire magnet is disassembled into a plurality of cylindrical parts, and each of these cylindrical parts is molded into a powder compact, sintered, and *magnetized to produce a separate magnet. Then, the magnets forming each of the obtained cylindrical bodies are assembled together. For this reason, each magnet company is magnetized in the same magnetic field direction in the radial direction, and when assembling the magnets, the direction of the magnetic field is uniformly distributed between each magnet.
Each magnet is marked with a mark that defines the direction of winding a so that the magnets can be connected in accordance with E*. Conventionally, marks such as III are made on the surface of powder compacts using a tool such as a scriber at the powder compact stage, but marks such as these lines are thin and shallow, making them difficult to see. At the same time, it is difficult to wear, but at the same time, it is easily erased by friction, making it very useful and reliable during assembly.

The present invention has been made in view of the circumstances of the 'fIJ article, and is a method for producing a sintered magnet that has a mark indicating the direction of the magnetic field t in a clear form and allows for good assembly work of joining a plurality of magnets. t-provide.

That is, the method for manufacturing a sintered magnet according to the present invention.

When forming a columnar or annular powder compact in a magnetic field,
The powder compact is sintered in the direction of the magnetic field on the end face of the powder compact, and is characterized by magnetic leakage.

EMBODIMENT OF THE INVENTION Below, the present invention will be described with reference to the drawings.

Figures 2 to 4 show the manufacturing method of the present invention.

An embodiment is shown in which the present invention is applied to a cylindrical self-fired magnet that is used by connecting a plurality of magnets, for example, two magnets, for the field of a micromotor.

First, as shown in FIG. 2, a cylindrical powder compact 1 having a desired length and diameter is press-molded in a magnetic field as shown in FIG. Namely.

The powder put into the die 2 is pressed by the reader 4 and the lower A/chi 5 to form the powder compact 1, and the excitation coil 6.6
A magnetic field is applied to the powder compact 1 in the radial direction thereof and in the direction required for the magnet. Here, one end surface of the powder compact 1 Kid excitation coil 6.
*r' which defines the magnetic field direction of the magnetic field applied by 6 is formed. That is, this groove 1 is formed in the radial direction of the powder compact 1 and in a direction corresponding to the magnetic field direction (for example, the same direction 11 as the Fi magnetic field direction).・Specifically +13
As shown in the figure, protrusions 41 are formed on the 14 sides of the Δy edge 4, and protrusions 4a are formed in the direction of the powder compact 10 in order to press the powder t5 from the Δy edge 4. This yeast r is powder j! Death to form 1 and its existence 1! E or @II-FCjPil, and when clearly meeting the scratches on the surface of the powder compact 1, the strength is sufficient so that the In stage KtI4 will not be destroyed by 8 mm. It is formed with a depth t'. The first one is @F is 嘱l.
aw, 鑵さα5 ai t-Freeze the cross section of the middle tomoe shape 1
It is. It is preferable that @y be formed on both sides 111+1 facing toward one end of the powder compact.

Sinter the powder LL shape 1 shaped like a grain.

Next, a magnetic field is applied to the obtained sintered body in the direction of the magnetic field necessary for the magnet (i.e., the same magnetic field as the magnetic field applied during molding of the S powder compact 10, and the same magnetic field t' as the magnetic field t'). 44) 6. In other words, the direction of the magnetic field in the S, ##vFi magnet is defined.

Therefore, when assembling the magnet, a! If you say as shown in Figure 4, it will be 21i! The magnets 1' and 1' are coaxially connected, and the grooves 1°rVt formed in each magnet 1.1' are positioned in the same direction so that the positions of the two coincide. For this reason, magnet 1' and magnet 2' are positioned and connected so that the directions of their respective magnetic fields coincide. In this case, groove 7
, 7 are clearly formed during molding of the powder compact 1, and 67t
In order to do so, follow the instructions while looking at the yeast r t vt.
, J/ positioning 1: Can be done easily and accurately. Then, the magnets 11 and '41 are inserted and arranged inside the yoke ring 8 of the micromotor. For example, if a groove am is formed at the end of the yoke ring 8, the magnet If, 11 can be attached to the yoke ring by matching the position t-@1m of the groove 7 of the magnet 1'. 8
16] 1 inside! It can be easily and accurately placed.

Note that only one end face of the magnet 1' is missing 1°' in the groove r, +1:
+ May be formed on the end face.

jl! Figure 5 shows another embodiment, in which a groove "r" is formed at one end of the magnet 1' and a projection 9t is formed at the other end. 1′
It is formed at the same position as the groove r along the radial direction of the groove r. As shown in FIG. 6, this magnet is produced by magnetically forming a powder compact 1 using an upper punch 4 having a protrusion 4a toward the lower end and a lower punch 5 having #15& on the f4A surface. Forming grooves 1 and protrusions 9 on the end surface of the molded body 1,
Next, the powder compact is manufactured by sintering and magnetizing it. When assembling the magnet 1', the protrusion 9 of one magnet 1' and the groove 7 of the other magnet 1' are engaged with each other.
By connecting the tubes p and 1', the magnets J/ and 1'l can be easily and accurately positioned so that the directions of their respective magnetic fields coincide. Moreover, the mutual rotation of the magnets J/ and J/ can be prevented by the engagement between the protrusion 9 and the tar. The protrusion is groove 7
The magnets 11 and 1/ can be connected without any gaps, and this is particularly effective when three or more magnets 1' are connected.

Note that the manner in which the grooves and projections are formed is not limited to the embodiments described above, and for example, only the projections may be formed on one end surface or both end surfaces of the magnet.

The directions of the grooves and protrusions are not limited to being the same as the direction of the magnetic field in the magnet, but the direction of the magnetic field can be regulated so that the directions of the respective magnetic fields can be matched when magnets are connected. Anything that adds up is good. The shape of the magnet is limited to cylindrical.

It may be cylindrical or annular, and further may be a regular square prism or a regular square ring.

As explained above, in the method for producing a sintered magnet of the present invention, the grooves and protrusions that correspond to the direction of the magnet's magnetic field are formed clearly and precisely during the magnetic field forming of the powder compact, so that a plurality of magnets can be formed into the same shape. When connecting the magnets with the same magnetic field direction, the magnets can be easily and accurately aligned.

[Brief explanation of drawings]

The first reason is an explanatory diagram showing a process S for magnetic field compacting of a powder compact,
Figures 2 to 1I41￥1 show an embodiment of the method of the present invention, in which Figure 2 is a perspective view showing a powder compact, FIG. 3 is an explanatory diagram showing the molding M'lr of the powder compact, and Fig. 4 is a perspective view showing the assembled state of the magnet wAt, Fig. 5 and Fig. 6 show other embodiments, Fig. 5 is a perspective view showing the assembled state of the magnet at, and Fig. 6 is a perspective view showing the assembled state of the magnet. It is an explanatory view showing the shape of the body. 1...Powder compact, 1'...Magnet,! -Gui, 4
゜5...Sunchi, 6...J excitation coil, 1...Groove,
t...Protrusion.

Claims (1)

[Claims] When a columnar or annular powder compact is subjected to magnetic field compaction,
Grooves and/or protrusions defining the direction of the magnetic field are formed on the end face of the powder compact. A method for manufacturing a sintered magnet, which comprises subsequently sintering and magnetizing the m-distributed powder compact.