JPH04359656A - Rotor yoke - Google Patents

Abstract

PURPOSE:To enhance breakdown strength of magnet layer arranged on the outer periphery by extruding a metallic base material having a metallic magnet layer into a multilayer cylindrical member, subjecting the cylindrical member to predetermined shaping and magnetizing the metallic magnet layer. CONSTITUTION:A basic material 30 integrating a case 28, a core member 32 and a metallic magnet layer 23 is extruded into a cylindrical member wherein the core member 32, the metallic magnet layer 23 and the case 28 are integrated substantially in concentric. The case 28 formed on the outer periphery of the cylindrical member is then cut and the cylindrical member is subjected to predetermined shaping thus forming a rotary yoke 25 having the metallic magnet layer 23. The metallic magnet layer 23 is then magnetized in order to considerably enhance breakdown resistance.

Description

[Detailed description of the invention]

0001

[Table of Contents] The present invention will be explained in the following order. Industrial field of application Conventional technology (FIGS. 11 to 13) Problems to be solved by the invention (FIGS. 11 to 13) Means for solving the problems (FIGS. 1, 5, and 9) Effects (FIGS. 1 to 13)
, FIGS. 5 and 9) Embodiment (1) First embodiment (FIGS. 1 to 7) (2) Second embodiment (FIGS. 8 and 9) (3) Other embodiments (FIG. 10) effect

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor yoke, and is suitable for application to a rotor yoke constituting a capstan motor of, for example, a video tape recorder.

0003

[Prior Art] Conventionally, for example, video tape recorders (VT
Some capstan motors in R) have a configuration as shown in FIG.

That is, the capstan motor 1 has bearings 3 and 4 at the center of the plane of a fixed member (bracket) 2.
A rotary shaft 5 is rotatably supported via the rotary shaft 5, and a yoke plate 6 of a rotor yoke 10 is fitted and fixed to one end of the rotary shaft 5.

A driving magnet 8 is fixed to the upper side of the yoke plate 6, and a coil 7 is provided on the lower side of the fixed member 2 at a position opposite to the driving magnet 8.

[0006] Therefore, by applying a drive current to the coil 7, the rotor yoke 10 and the rotating shaft 5 can be rotated together. (2) can be rotated.

In the rotor yoke 10, a resin magnet 11 for a magnetic detection element is formed on the outer periphery of the yoke plate 6 so as to cover the outer periphery of the yoke plate 6, and the resin magnet 11 is magnetized. As a result, magnetic poles consisting of north and south poles are formed alternately along the direction of rotation.

Furthermore, a resin magnet 11 is attached to the lower surface of the fixing member 2.
A magnetic sensor 13 made of an MR element (magnetic detection element) is held by a holding member 12 at a position facing the magnetized surface of the magnetic sensor.

Therefore, when the rotor yoke 10 rotates, the resin magnet 11 rotates together with the rotor yoke 10, so that the magnetic sensor 13 outputs a frequency signal corresponding to the rotation speed of the rotor yoke 10, and the control unit (not shown) The rotation speed of the capstan motor 1 is controlled.

0010

However, in the rotor yoke 10 having such a structure, in addition to the fact that the iron-based material such as SECC, which forms the yoke plate 6, and the resin magnet 11 have different linear expansion coefficients, the resin magnet When molding the resin magnet 11, internal stress remains, which causes damage such as cracks to the resin magnet 11.

On the other hand, as shown in FIG. 12, there is a method of constructing the rotor yoke 10 by fitting an annular resin magnet 15 onto the outer circumferential surface 6B of the yoke plate 6 using an adhesive. However, even in this case, there was a problem that damage to the resin magnet 15 could not be avoided due to the difference in coefficient of linear expansion between the yoke plate 6 and the resin magnet 15.

Furthermore, as shown in FIG. 13, the rotor yoke 1
0, when the gear 11A is integrally molded on a part of the resin magnet 11 to drive an external device, the resin magnet 11 is made of a relatively fragile material.
There was a problem with 1A being damaged.

The present invention has been made in consideration of the above points, and aims to propose a rotor yoke that can further increase the breakage resistance of the magnet layer disposed on the outer periphery.

[0014]

[Means for Solving the Problems] In order to solve the problems, in the first invention, in the rotor yoke 25 forming the rotating part of the motor, a metal core material 32 and a metal magnet are attached to the outer periphery of the core material 32. Metal matrix 30 with layer 23
Then, a multilayered columnar member 31 with the metal magnet layer 23 integrated on the outer periphery is created by extrusion processing, and the columnar member 31 is processed into a predetermined shape and the metal magnet layer 23 is attached. By magnetizing, a metal magnet 23 is integrally formed on the outer peripheral portion. In addition, in the second invention, in the rotor yoke 25 forming the rotating part of the motor, a multi-layered cylindrical metal base material 52 having a metal magnet layer 23 integrally formed on the outer periphery by precipitation processing is provided. By processing the metal magnet layer 23 into a predetermined shape and magnetizing the metal magnet layer 23, the metal magnet 23 is integrally formed on the outer periphery.

[0015]

[Operation] Magnet layer 2 provided on the outer periphery of the rotor yoke 25
3 is integrally formed with the rotor yoke 25 using a metal magnet using extrusion processing or precipitation processing,
The breakage resistance strength of the magnet layer 23 can be further improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

(1) First Embodiment In FIG. 1, in which parts corresponding to those in FIG. A metal magnet layer 23
The rotor yoke 25 has a two-layer structure in which a rotor yoke 25 is formed.

As shown in FIG. 2, this rotor yoke 25 has a cylindrical core material 32 made of iron (Fe) placed in the center of the plane of a cup-shaped case 28 made of iron (Fe). Manganese (M
n) and aluminum (Al), solidify the Mn.Al magnetic powder by pressurizing them, and then melt the Mn.Al magnetic powder by heating.

As a result, as shown in FIG. 3, the once molten Mn.Al magnetic powder layer is cooled and alloyed to form the metal magnet layer 23 around the core material 32, and the case 28, the core The material 32 and the metal magnet layer 23 are each integrated to obtain a cylindrical base material 30.

Furthermore, as shown in FIG.
Insert from the 9A side.

[0021] This first cylindrical part 29B is formed in a size that matches the diameter of the base material 30, and furthermore, the first cylindrical part 29B is
Following the cylindrical portion 29B, a tapered second cylindrical portion 29C whose diameter gradually becomes smaller is formed, and a third cylindrical portion 29D is formed following the second cylindrical portion 29C.

This third cylindrical portion 29D is similar to the first cylindrical portion 2.
The diameter of the first opening 29 is smaller than that of the opening 9B.
The base material 30 inserted from A is pushed out from an opening 29E provided in the third cylindrical portion 29D.

That is, as shown in FIG.
The base material 30 inserted through the opening 29A is heated at approximately 700 degrees.
3000~500 while heating to a temperature of about 1000 degrees
By pressing with a pressure P of about 0 [t/cm2], the base material 30 closes the opening 29 on the third cylindrical portion 29D side.
From E, the diameter is reduced and extruded.

The cylindrical member 31 obtained from the opening 29E side by such extrusion processing has a core member 32, a metal magnet layer 23 and a case 28 arranged in substantially concentric circles from the center, similar to the base material 30. is integrated into.

After the case 28 formed on the outer periphery of the cylindrical member 31 is removed by cutting, the cylindrical member 31 is removed as shown in FIG. By cutting 31 at cutting surfaces 33A, 33B, 33C, . . . perpendicular to the longitudinal direction, a disk-shaped piece member 35 as shown in FIG. 6(B) is obtained.
get.

Further, by subjecting the section member 35 to a predetermined shape processing such as hot forging and cutting, the shape shown in FIG. 6 (
As shown in C), manganese aluminum (Mn・Al
) A rotor yoke 25 having a metal magnet layer 23 made of an alloy.
can be formed.

Therefore, by magnetizing the metal magnet layer 23 made of the manganese-aluminum alloy, it can be used as a magnet layer for detecting rotational speed.

In the above configuration, the rotor yoke 25 is
The yoke plate 22 is formed of iron material, and
The yoke plate 22 has a two-layer structure in which a metal magnet layer 23 made of a manganese-aluminum alloy magnet is integrally formed on the outer periphery of the yoke plate 22 by extrusion processing, and both the yoke plate 22 and the metal magnet layer 23 are made of metal materials. It is formed by

Therefore, the breakage resistance can be further increased compared to the conventional case in which resin magnets are formed on the outer periphery of the yoke plate using methods such as molding or adhesion.

According to the above structure, in the rotor yoke 25, the metal magnet layer 23 for rotational speed detection made of a manganese-aluminum alloy magnet is integrally formed on the outer periphery of the yoke plate 22 by extrusion. It is possible to avoid damage to the rotational speed detection magnet section.

By the way, by forming the metal magnet layer 23 (manganese-aluminum alloy magnet layer) for speed detection by extrusion processing, it is possible to achieve a much simpler method without using complicated methods such as conventional molding or gluing. The rotor yoke 25 can be manufactured by the method.

[0032] In the above-described embodiment, a case was described in which the rotor yoke 25 was formed of the core material 32 and the metal magnet layer 23, but the present invention is not limited to this.
An intermediate layer may be provided between the metal magnet layer 23 and the metal magnet layer 23.

That is, FIG. 7 shows the cut member 45 before the formation of the rotor yoke provided with the intermediate layer 46, and between the core material 32 made of iron (Fe) and the metal magnet layer 23 made of manganese aluminum (Mn.Al) alloy. For example, manganese aluminum (Mn・A
By providing an intermediate layer 46 having a linear expansion coefficient between those of iron (Fe) and manganese aluminum (Mn/Al) alloy, such as iron (Fe) alloy, It is possible to avoid cracking of the metal magnet layer 23 due to a difference in linear expansion coefficient when the section member 45 is cooled.

Further, in the above embodiment, iron (Fe)
Manganese aluminum (Mn・Al) on the surface of the core material 32 made of
Although the case has been described in which the metal magnet layer 23 is formed of an alloy, the present invention is not limited to this, and metal magnet layers may be formed of various other metals.

(2) Second Embodiment FIG. 8 shows a rotor yoke processing method according to a second embodiment of the present invention.
Aluminum (Al), manganese (Mn), and iron (Fe) are prepared by placing powders of n) and iron (Fe) in a cylindrical mold and heating them to a temperature higher than the melting points of the three metals.
) A uniform alloy base material 51 is obtained.

Here, aluminum (Al), manganese (
The respective melting points of Mn) and iron (Fe) increase in the order of aluminum (Al), manganese (Mn), and iron (Fe).

Therefore, the alloy base material 51 is further made of aluminum (Al) and manganese (Mn) having melting points or higher and iron (Fe).
), only aluminum (Al) and manganese (Mn) become the alloy base material 5.
A so-called precipitation process is applied to the outer periphery of 1.

By cooling in this state and cutting the upper and lower surfaces of the cylindrical shape, a core material 32 made of iron (Fe) is formed in the center as shown in FIG. Manganese aluminum (Mn/Al) on the outer periphery of 32
A metal magnet layer 23 made of an alloy is integrally formed.

The base material 52 formed in this way is shown in FIG.
A rotor yoke 2 having a metal magnet layer 23 on the outer periphery is manufactured using a method similar to that described above.
5 (FIG. 6(C)).

In the above configuration, the rotor yoke 25 is
The yoke plate 22 is made of iron (Fe), and the metal magnet layer 23 made of a manganese-aluminum (Mn-Al) alloy is integrally formed on the outer periphery of the yoke plate 22 by precipitation processing. , yoke plate 2
2 and metal magnet layer 23 are both formed of metal materials.

[0041] Therefore, the breakage resistance can be further increased compared to the conventional case in which resin magnets are formed on the outer periphery of the yoke plate using methods such as molding or adhesion.

According to the above structure, the metal magnet layer 23 for detecting the rotational speed made of a manganese aluminum alloy magnet is integrally formed on the outer circumference of the yoke plate 22 by precipitation processing, so that the rotational speed cannot be detected as in the conventional case. Damage to the detection magnet portion can be avoided, and the rotor yoke 25 can be manufactured by a simpler method without using complicated methods such as conventional molding or bonding.

[0043] In the above embodiment, manganese (
Mn) Alloy base material 5 made of aluminum (Al) and iron (Fe)
Although the case has been described in which the metal magnet layer 23 made of a manganese-aluminum alloy is formed by performing precipitation processing on 1, the present invention is not limited to this, and various other metal materials may be used. .

(3) Other Embodiments In the above embodiments, a case was described in which only the metal magnet layer 23 for speed detection was formed on the outer periphery of the rotor yoke 25, but the present invention is not limited to this. It is also possible to provide a gear for this purpose.

In this case, as shown in FIG. 10, a gear 61 made of a predetermined resin material is molded onto the upper end of the metal magnet layer 23 formed on the outer periphery of the yoke plate 22 by extrusion or precipitation. It may be provided depending on the situation.

[0046] In this way, the material of the gear 61 can be arbitrarily selected to have high strength, and the gear 61 can be made of a material with high strength.
The strength can be further improved.

Furthermore, in the above-described embodiments, the metal magnet layer 23 is used for detecting rotational speed, but the present invention is not limited to this. It can be used as a variety of magnets, such as as a magnet.

Further, in the above-described embodiment, the present invention was applied to the rotor yoke constituting a capstan motor, but the present invention is not limited to this, and can be applied to the rotor yoke of various other motors. .

[0049]

As described above, according to the present invention, the magnet layer provided on the outer periphery of the rotor yoke is formed by extrusion processing or precipitation processing, so that the magnet layer can be formed by metal magnets. can. In this way, it is possible to realize a rotor yoke in which the damage resistance of the magnet layer can be further improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a capstan motor using a rotor yoke according to the present invention.

FIG. 2 is a perspective view showing a method of forming a base material used in extrusion processing.

FIG. 3 is a sectional view showing the structure of a base material used in extrusion processing.

FIG. 4 is a cross-sectional view showing extrusion processing.

FIG. 5 is a cross-sectional view for explaining the formation of a cylindrical member by extrusion.

FIG. 6 is a cross-sectional view for explaining the process of forming a rotor yoke from a cylindrical member formed by extrusion.

FIG. 7 is a cross-sectional view showing an example in which an intermediate layer is provided between the core material and the metal magnet layer.

FIG. 8 is a perspective view showing an alloy base material according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view showing an alloy base material on which a metal magnet layer is formed by precipitation processing.

FIG. 10 is a perspective view showing another embodiment.

FIG. 11 is a sectional view showing a capstan motor using a conventional rotor yoke.

FIG. 12 is a sectional view showing a rotor yoke using a conventional annular magnet.

FIG. 13 is a perspective view showing a conventional rotor yoke with gears.

[Explanation of symbols]

1, 20... Capstan motor, 6, 22... Yoke plate, 10, 25... Rotor yoke, 11... Resin magnet, 23... Metal magnet layer, 28... Case, 30...
Base material, 31... Cylindrical member, 35, 45... Section member, 5
1...Alloy base material.

Claims (2)

[Claims] [Claim 1] In a rotor yoke that forms a rotating part of a motor, extrusion processing is performed on a metal base material having a metal core material and a metal magnet layer on the outer periphery of the core material, so that the outer periphery has the above-mentioned properties. A cylindrical member having a multilayer structure with an integrated metal magnet layer was created, and the cylindrical member was processed into a predetermined shape and the metal magnet layer was magnetized to integrally form a metal magnet on the outer periphery. A rotor yoke characterized by: [Claim 2] In a rotor yoke forming a rotating part of a motor, a predetermined shape processing is performed on a cylindrical metal base material with a multilayer structure in which a metal magnet layer is integrally formed on the outer periphery by precipitation processing. A rotor yoke characterized in that a metal magnet is integrally formed on an outer peripheral portion by magnetizing the metal magnet layer.