JPH0768571B2 - Composite magnet and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite magnet material, in which a permanent magnet material produced by powder metallurgical means and another metal material are concentrically in close contact with each other, and particularly a magnet assembly for a magnetic sensor. The present invention relates to a composite material containing a magnet material for obtaining the same and a manufacturing method thereof.

[0002]

2. Description of the Related Art A magnetic material and a magnetic detection sensor such as a magnetic semiconductor element are attached to a part of a shaft and a structure part facing the shaft, respectively, and rotation of the shaft is detected by detecting relative movement of both. Movement is being detected. Further, it is also known that a gear-shaped soft magnetic material is attached to a shaft, and a sensor including a coil and a permanent magnet is attached to a structure portion facing the gear to detect rotation of the shaft.

[0003]

Generally, since permanent magnets are extremely brittle, it is difficult to machine such as drilling and threading, and also difficult to join such as welding and brazing. At the time of mounting, it is necessary to use a mounting member having a complicated structure or to bond the mounting member with an organic adhesive. It was hard to say that vibration resistance and impact resistance were sufficient for use in parts.

The present applicants efficiently produce a composite magnet material in which a metal material that is easily machined and bonded for attachment and a magnet alloy produced by powder metallurgical means are firmly bonded. To make an invention for
We applied for a patent as 149465.

The invention of the above-mentioned patent application is such that a magnetic material powder is contained in a metal capsule having sufficient strength and malleability,
If necessary, a rod or tube of a metal material having sufficient strength and malleability is housed, this is subjected to hot or warm extrusion processing, and this extrudate is cut into a predetermined size.
However, since the product requires a sufficient extrusion ratio at the time of extrusion, it was inconvenient to obtain a composite magnet material having a large diameter of 50 mm or more. Further, when a very thin composite magnet material is required, the magnet portion also becomes thin, which causes a problem in strength, and the ratio of cutting allowance becomes large, which is also disadvantageous in terms of yield.

Similar to the inventions of the above-mentioned patent applications, the present invention is such that a magnet material made by powder metallurgical means is firmly bonded to a metal material which is easy to machine or join for attachment. The present invention intends to efficiently manufacture a large-diameter product and a thin composite magnet material having a diameter of 50 mm or more.

[0007]

In the composite magnet material according to the present invention, a ring-shaped magnet material is held from three sides by a concentric ring-shaped metal material having good machinability and joining workability. is there. Such a composite magnet material is manufactured as follows. First, a case is prepared which is made of metal having sufficient strength and malleability, has a ring shape, and has a groove concentric therewith. Next, the groove is filled with a powder of a magnetic material, and this is subjected to hot or warm upsetting (pressing) together with the case. Then, the surface is machined to a predetermined size to obtain a product.

Here, it is desirable that the metal material for the case and the magnet material have thermal expansion coefficients as close to each other as possible, and the difference should not exceed 2.5 × 10 ⁻⁶ / ° C. This is because if the difference in the coefficient of thermal expansion between the two materials is large, the magnet material may crack during the cooling process during manufacturing, or a gap may be created between the two materials, resulting in poor adhesion.

A preferable combination of the permanent magnet material and the case material is a FeMnNi-based alloy (22.2 × 10 ^-6 / ° C) for an MnAlC-based magnet (22.6 × 10 ^-6 / ° C).
℃), brass (20.8 × 10 ^-6 / ° C), etc., nickel (13.3 × 10 ^-6 / ° C), 12Cr stainless steel for alnico magnets (11.3 × 10 ^-6 / ° C). (1
1.7 × 10 ⁻⁶ / ° C.), 18Cr stainless steel (11.
3 × 10 ⁻⁶ / ° C.) and other NdFeB magnets (4.6 × 10
^-6 / ° C.) for a 42 Permalloy (3.9 × 10 ^-6 /
℃). The coefficient of thermal expansion is shown in parentheses.

When the groove of the case does not open upward when the magnet material powder is filled, or when the case filled with the magnet material powder is loaded into the upsetting die, the magnet material powder spills from the groove. When such a posture is taken, it is preferable to add a high temperature volatile binder such as wax to the magnet material powder and then fill the case.

If the magnet material powder is filled in the case and then a suitable lid is applied by welding, caulking or the like, not only can the magnet material powder be prevented from spilling out from the groove, but It is possible to prevent the magnet material powder from being oxidized during heating prior to the step.

As the magnet material powder, those produced by any method can be used, but those produced by the gas atomizing method are preferable because spherical powder particles can be obtained, and those produced by an inert argon gas are of high quality. Excellent in terms of

At the time of upsetting, there are a method of restraining one or both of the inner and outer peripheral surfaces of the case with a die and a method of not restraining the die, but either method may be adopted.

[0014]

In the manufacturing process described above, the magnet material powder filled in the case changes into a solid material when subjected to the upsetting process and completely adheres to the metal forming the case. Here, what is important is the difference in thermal expansion coefficient between the case material and the magnet material. For example, SC material (1
4.9 × 10 ⁻⁶ / ° C.), SUS 304 material (18.8)
X10 ^-6 / ° C), copper (17.0 × 10 ^-6 / ° C), etc. When a MnAlC-based magnet material with a relatively large coefficient of thermal expansion is located outside, shrinkage in the cooling process after manufacturing The outer permanent magnet material is frequently cracked due to the difference in Also,
On the other hand, when an alnico magnet having a very small thermal expansion coefficient is located outside the SUS 304 material, a gap is generated between the two after cooling. However, if the difference in the coefficient of thermal expansion between the permanent magnet material and the case material is sufficiently small, cracks or gaps do not occur.

The composite material obtained as described above is machined to a predetermined size and magnetized to a permanent magnet for use. For example, when it is used to detect the rotation of a shaft, a central hole made of the case material is machined to a size that fits the shaft, and the case material in a portion facing the magnetic sensor is removed by machining.

Therefore, according to the present invention, it is possible to efficiently manufacture the composite material in which the easily workable metal material and the magnet material are firmly bonded to each other. On the other hand, mechanical processing such as punching, cutting, and thread cutting, and joining processing such as welding and brazing can be easily performed.

[0017]

EXAMPLE A ring-shaped case 1 as shown in FIG.
Has a concentric ring-shaped groove 2 on its upper end surface.
The material of Case 1 is FeMnNi-based alloy (Mn: 15% by weight, Ni: 15% by weight, balance Fe, thermal expansion coefficient 22.2).
× 10 ⁻⁶ / ° C.), and the dimensions of each part are as follows. Outer diameter 119mm Inner diameter 85mm Height 9.0mm Groove outer diameter 116mm Groove inner diameter 105mm Groove depth 6.5mm

In the groove 1, a MnAlC type magnet alloy (Mn: 6
9.05% by weight, Al: 29.80% by weight, Ni: 0.
7% by weight, C: 0.45% by weight, thermal expansion coefficient 22.6 ×
10 ^-6 / ° C) gas atomized powder (maximum particle size 209μ
m, average particle diameter 43 μm) 3 and filled in FIG. 1 (b).
As described above, a ring-shaped lid 4 is covered and welded to form a billet 5. The material of the lid 4 is the same as that of the case 1, and the thickness is 1 m.
m.

The billet 5 is heated to 700 ° C. and the inner diameter 12
Inserted in a 0 mm die, height 5.5 mm (upset ratio 0.
55) was subjected to warm upsetting to obtain upsetting material 6 shown in FIG. The upsetting material 6 includes the metal parts 11 and 14 transferred from the case 1 and the lid 4, respectively, and the magnet material powder 3
And a solid magnet alloy portion 13 which has been transferred from the above, the magnet alloy portion 13 is in close contact with the metal portions 11 and 14 to form an alloy diffusion layer, and is completely integrally joined.

In the above-mentioned upsetting material 6, the lid portion is removed by machining to expose the magnet alloy portion 13 and the case portion is finished to a predetermined size, and a product 7 as shown in FIG. And In this product 7, the magnet alloy portions 13 are alternately magnetized into S poles and N poles at equal intervals along the circumferential direction, and then the center hole 8 is fitted to the rotating shaft 9 as shown in FIG. The magnetic sensor 10 is used by arranging it at a fixed position facing the alloy portion 13. When the shaft 9 rotates, the magnetic sensor 1
The rotational speed and angular displacement of the shaft 9 can be measured by the AC signal generated by 0.

The embodiment shown in FIG. 3 uses a case 31, a magnet material powder 33, and a lid 34 made of the same material as the embodiment shown in FIG. 1, but differs in that the thickness of the lid 34 is large. . If the billet 35 is warm upset as in the first embodiment and the outer peripheral wall portion 36 is removed by machining, a product having the magnet alloy portion 43 exposed on the outer peripheral surface as shown in FIG. 4 can be obtained. it can. After magnetizing this product,
As shown in FIG. 4, it fits on the shaft 9 and the magnet alloy part 4
The magnetic sensor 10 is installed facing the No. 3 and used.

FIG. 5 shows a different manufacturing method for obtaining the product shown in FIG. 4, wherein the case 51 has a groove 52 on the outer peripheral surface, and wax is added to the groove 52 as a binder. The magnet alloy powder 53 is filled. The upsetting is performed by loading the cold billet 55 into the heated die and waiting for the temperature of the billet 55 to rise. The wax added to the magnet alloy powder is volatilized by the temperature rise in the die. In the upsetting material thus obtained, the magnet alloy portion 43 is exposed on the outer peripheral surface as shown in FIG. 4, even if the outer peripheral surface is not machined.

FIG. 6 shows a further different process for obtaining the product shown in FIG. The groove 52 of the case 51 is filled with the wax-added magnet alloy powder 53 by the method described with reference to FIG. 5, and the billet 55 shown in FIG.
After the same state as described above, a thin-walled cylindrical sleeve 54 is fitted on the outer side, and the sleeve 54 is fixed by welding or caulking to obtain a billet 56. This billet is warmed and warm upset in the same manner as the embodiment of FIG. 1 or FIG. 3 to obtain an upset material. By lightly machining the outer peripheral surface of this upsetting material, the magnet alloy portion 43 can be exposed on the outer peripheral surface as shown in FIG.

[0024]

As described above, according to the present invention,
A composite magnet material in which a ring-shaped magnet alloy is firmly bonded to a ring-shaped easily workable metal material can be efficiently manufactured regardless of its diameter.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a manufacturing process of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a usage state of a product obtained by the example shown in FIG.

FIG. 3 is a sectional view of a billet according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a usage state of a product manufactured using the billet shown in FIG.

5 is a sectional view of a billet in another embodiment for obtaining the product shown in FIG.

FIG. 6 is a sectional view of a billet in yet another embodiment for obtaining the product shown in FIG.

[Explanation of symbols]

 1 case 2 groove 3 magnet material powder 4 lid 5 billet 6 upsetting material 7 product 31 case 32 groove 33 magnet material powder 51 case 52 groove 53 magnet material powder 54 sleeve 55 billet 56 billet

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Kazuhiko Hiraoka Inventor Kazuhiko 3007 Nakajima, Himeji, Himeji, Nakajima, 1300, Sanyo Special Steel Co., Ltd. (72) Inventor Ichiro Takasu 3007 Nakashima, Himeji, Himeji, Sanyo, Sanyo Special Steel Co., Ltd. (72) Inventor Yoshikazu Tanaka 3007 Nakajima, Shikoma-ku, Himeji, Hyogo Prefecture Sanyo Special Steel Co., Ltd. (72) Inventor Nobuyuki Kato 1006, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-4-354803 (JP, A)

Claims (3)

[Claims] 1. A case in which one or a plurality of grooves are concentrically provided in a ring-shaped metal material having sufficient strength and malleability is used, and the grooves are filled with magnet material powder to form a billet. A method for producing a composite magnet material, comprising hot or warm upsetting of the billet. 2. A billet is prepared by using a case in which one or a plurality of grooves are concentrically provided in a ring-shaped material made of an FeMnNi-based alloy, and the grooves are filled with a powder material of an MnAlC-based magnet alloy by a gas atomizing method. M, and this billet is hot or warm upset processed.
Method for manufacturing nAlC-based composite magnet material. 3. A peripheral surface or an edge having sufficient strength and malleability.
Ring-shaped gold having one or a plurality of concentric grooves on the surface
The metal material and the metal material located in the groove and firmly bonded to the metal material.
It consists of a ring-shaped permanent magnet material that is
The permanent magnet material is characterized by a void-free powder sintered structure
And a composite magnet.