JPH099538A - Rotary machine rotor, manufacture of the rotor and magnet unit - Google Patents

Abstract

PURPOSE: To provide a rotary machine rotor in which joint strengths of the respective permanent magnets are high and joint structures of the respective permanent magnets have high reliability. CONSTITUTION: A rotary machine rotor 1 has a rotor main part 3 and a plurality of magnet units 4 attached to the outer circumference of the rotor main part 3. The respective magnet units 4 are composed of bases 13 attached to the rotor main parts 3 and permanent magnets 15 which are bonded to the bases 13 in a heating atmosphere with joint layers 14 made of solder material. By employing the joint method with solder material and employing the magnet unit, the joint states of the permanent magnets 15 can be confirmed and the required objective can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for a rotating machine, a method for manufacturing the rotor and a magnet unit. The rotating machine includes a motor and a generator.

[0002]

2. Description of the Related Art Heretofore, as this type of rotor, one in which a permanent magnet is joined to a steel rotor body using a synthetic resin adhesive is known (see, for example, Japanese Patent Publication No. 61-33339).

The reason why the synthetic resin adhesive is used in this way is that permanent magnets, especially permanent magnets containing rare earth elements, are very brittle and therefore have poor machinability and, when exposed to high temperatures, have a metallic structure. Since it changes, the magnetic properties are affected accordingly, and therefore, when attaching the permanent magnet to the steel rotor body, it is not possible to adopt attachment means such as insertion structure, screwing, welding, etc. Is.

[0004]

However, in the joining using the synthetic resin adhesive, the temperature of the rotor rises as the rotating machine operates. For example, when the rotor temperature reaches 100 ° C., the joining strength of the permanent magnets is remarkably reduced. There is a problem such as doing. Under such circumstances, it is impossible to meet the demand for high-speed rotation of the motor.

In view of the above, the present invention has a high bonding strength of each permanent magnet, does not impair the bonding strength of each permanent magnet even when the rotor temperature rises, and has a high reliability of the bonding structure of each permanent magnet. An object of the present invention is to provide a rotor for a rotating machine having high property.

Another object of the present invention is to provide the above manufacturing method capable of improving the productivity and the yield of the rotor for a rotating machine.

A further object of the present invention is to provide a magnet unit which contributes to improving the productivity of a rotor for a rotary machine and which can avoid cracking of the permanent magnet due to rise and fall of the rotor temperature.

[0008]

A rotor for a rotating machine according to the present invention comprises a rotor body and a plurality of magnet units attached to an outer peripheral portion of the rotor body, each magnet unit being attached to the rotor body. It is characterized by comprising a pedestal to be attached and a permanent magnet joined to the pedestal under heating via a joining layer made of a brazing material.

The method of manufacturing a rotor for a rotating machine according to the present invention comprises the steps of obtaining a plurality of superposed products by interposing a brazing filler metal between the permanent magnet and the pedestal, and heating the superposed products, Using a step of obtaining a plurality of magnet units in which a permanent magnet and a pedestal are joined together through a joining layer made of the brazing material, and a step of attaching each magnet unit to the outer peripheral portion of the rotor body through the pedestal Is characterized by.

The magnet unit according to the present invention comprises a pedestal formed by laminating a plurality of steel plates, and a permanent magnet joined to the pedestal under heating via a joining layer made of a brazing material. At least both ends of the pedestal in the steel plate stacking direction are characterized in that there is a gap generated between the adjacent steel plates due to heat bonding.

[0011]

In the rotor, since the joining method using the brazing material is adopted for joining the permanent magnets, the joining strength of the permanent magnets is high, and the rotor temperature is not changed by the synthetic resin adhesive when the rotating machine is operated. Decrease bonding strength, eg 10
Even if the temperature rises to 0 ° C, the bonding strength of each permanent magnet is not impaired.

Moreover, in each magnet unit, it is possible to attach each magnet unit to the rotor body after confirming the joining state of the permanent magnet to the pedestal. Highly reliable.

In the above manufacturing method, since the heat capacity of each pedestal is relatively small in manufacturing each magnet unit,
It is possible to raise the temperature to the heating temperature required for joining and to cool it after the heating and joining in a relatively short time, thereby shortening the time required for the joining process.

Further, since each magnet unit is attached to the rotor main body through the pedestal, there is a high degree of freedom in selecting the attachment means. For example, means such as dovetailed groove fitting, welding, screwing, caulking, etc. Can be adopted, and the mounting can be easily performed.

As a result, the productivity of the rotor can be improved.

Further, in manufacturing each magnet unit,
Since a means for heating the superposed product composed of the permanent magnet, the brazing material and the pedestal is adopted, it is possible to make the heating state of each superposed product uniform and suppress the occurrence of defective bonding as much as possible. Therefore, the yield of the rotor can be improved.

For example, if a method of directly heating and joining a plurality of permanent magnets to the outer periphery of the rotor body by using a brazing material is adopted, the heat capacity of the rotor body is relatively large, and therefore the time required for the joining process is the same. The number of permanent magnets is about twice that in the case of obtaining a magnet unit, and if one permanent magnet is cracked, the rotor is defective.
However, when the magnet unit is manufactured,
And, if it is used, the above problems can be avoided.

In the magnet unit, the magnet unit is easily attached to the rotor body via the pedestal, which contributes to the improvement of rotor productivity.

Further, as the rotor temperature rises and falls, thermal stress concentrates on both ends of the pedestal in the steel plate laminating direction. However, since there is a gap between the two adjacent steel plates on these two ends, there is a gap between them. The expansion and contraction of the steel sheet are absorbed by the gap, whereby the thermal stress on the both end sides can be relaxed and the occurrence of cracks in the permanent magnet can be avoided.

[0020]

1 and 2, a rotor 1 for a motor as a rotating machine is mounted on a cylindrical rotor body 3 formed by laminating a plurality of circular steel plates 2 and an outer peripheral portion of the rotor body 3. And a plurality of magnet units 4. The spline shaft portion 7 of the rotor shaft 6 is press-fitted into the spline hole 5 existing at the center of the rotor body 3, and both opening edge portions of the spline hole 5 are fixed to the rotor shaft 6 via welded portions 8.

The rotor body 3 comprises a boss portion 9 having a spline hole 5, a plurality of arm portions 10 extending radially from the outer peripheral surface of the boss portion 9, and a rim portion 11 connected to each arm portion 10. Become. The rim portion 11 is formed with a plurality of dovetail grooves 12 extending in the outer peripheral surface generatrix direction.

As shown in FIG. 3, each magnet unit 4 has a pedestal 13 having a cross section and a joining surface on the short parallel side of the pedestal 13 through a joining layer 14 made of a brazing material under heating. And a permanent magnet 15 joined together.

Each magnet unit 4 is attached to the rotor body 3 with its pedestal 13 fitted in the dovetail groove 12 of the rotor body 3.

In the rotor 1, since the joining method using the brazing material is adopted for joining the permanent magnets 15, the joining strength of the permanent magnets 15 is high, and the rotor temperature is kept at the synthetic resin adhesive as the motor is operated. Decrease the joint strength of
For example, even if the temperature is raised to 100 ° C., the bonding strength of each permanent magnet 15 is not impaired.

Moreover, in each magnet unit 4, after confirming the joining state of the permanent magnet 15 to the pedestal 13,
Since each magnet unit 4 can be attached to the rotor body 3, the reliability of the joint structure of each permanent magnet 15 in the rotor 1 is high.

As shown in FIG. 3, the pedestal 13 is formed by laminating a plurality of dovetail-shaped steel plates 16, and a caulking means 17 is used to join the steel plates 16.

As shown in FIG. 4, in the pedestal 13, at least both ends of the steel sheet laminating direction a, that is, in the illustrated example, over substantially the entire length in the direction a, the two steel sheets 16 adjacent to each other are formed by heat bonding. There is a gap b.

In the rotor 1, as the rotor temperature rises and falls, thermal stress concentrates on both ends of the pedestal 13 in the steel sheet laminating direction a. According to the above-mentioned structure, since a gap b exists between the steel plates 16 adjacent to each other on both end sides, expansion and contraction of the steel plates 16 are absorbed by the gap e,
As a result, the thermal stress on both end sides can be relaxed and the occurrence of cracks in each permanent magnet 15 can be avoided.

In manufacturing the rotor 1, as shown in FIG. 5, a brazing material such as a thin plate or a foil is formed between the joint surface 18 of the permanent magnet 15 and the joint surface 19 on the short parallel side of the pedestal 13. A step of obtaining a plurality of superposed products 21 (see FIG. 7 (a)) with the interposition of the brazing material 20 and the superposition products 21 are installed in a vacuum heating furnace, and the brazing material 20 is heated to a liquid, for example, under heating. Obtaining a plurality of magnet units 4 in which a permanent magnet 15 and a pedestal 13 are joined via a joining layer 14 made of a brazing material 20 in a phase state or in a solid-liquid coexistence state in which a solid phase and a liquid phase coexist. Figure 6
Each dovetail groove 1 existing on the outer peripheral portion of the rotor body 3 as shown in FIG.
2, the step of fitting the pedestal 13 of each magnet unit 4 and attaching each magnet unit 4 to the rotor body 3 is used.

In the above manufacturing method, each magnet unit 4
In manufacturing the above, since the heat capacity of each pedestal 13 is relatively small, it is possible to raise the temperature to the heating temperature required for bonding and to cool it after heating and bonding in a relatively short time. This shortens the time required for the joining process.

Further, since each magnet unit 4 is attached to the rotor body 3 via the pedestal 13, there is a high degree of freedom in the selection of the attachment means, and the fitting with the dovetail (pedestal 13) -dovetail groove 12 as described above. In addition to the above, it is possible to adopt means such as welding, screwing, and caulking. Therefore, each magnet unit 4 is easily attached to the rotor body 3 via the pedestal 13.

As a result, the productivity of the rotor 1 can be improved. In addition, when the presence-presence groove fitting method is adopted, each pedestal 13 and the rotor body 3 are welded to each other as necessary.

Further, in manufacturing each magnet unit 4, since a means for heating the superposed product 21 including the permanent magnet 15, the brazing material 20 and the pedestal 13 is adopted, the heating state of each superposed product 21 is adopted. Can be made uniform to suppress the occurrence of defective joints as much as possible, thereby improving the yield of the magnet unit 4, and hence the rotor 1.

Next, the heating and joining mechanism in the magnet unit 4 will be described with reference to FIGS. Before the heating of FIG. 7A, the permanent magnet 15 forming the stack 21 is formed.
And the length c ₁ of the pedestal 13 are equal. During heating in FIG. 7B, the permanent magnets 15 and the pedestal 13 expand and their length becomes longer than before heating, and c ₂ > c ₁ and c ₃ >.
c ₁ (however, c ₃ > c ₂ ) is established. After cooling, as shown in FIG. 4, in the cooling step, since the steel plates 16 on the pedestal 13 having the larger coefficient of thermal expansion contract and are joined to the permanent magnets 15, both steel plates adjacent to each other on the permanent magnet 15 side. A gap b is generated between 16 and as a result, the permanent magnet 15 side of the pedestal 13 is constrained to be longer than the length c ₁ before heating, and c ₄ > c ₁ (for example, c ₄ ≈1.01 ×
c ₁ ).

As a result, the thermal stress generated in the bonding layer 14 is relaxed as compared with the case where the length c ₃ of the pedestal 13 during heating is substantially restored to the length c ₁ before heating after cooling. Even if the permanent magnet 15 is fragile, it is possible to avoid the problem that the permanent magnet 15 is cracked.

The permanent magnet 15 is an NdFeB type permanent magnet.
Those containing rare earth elements such as magnets and SmCo-based permanent magnets
Used. Such a permanent magnet 15 is used in the joining process.
When the heating temperature T becomes T> 650 ° C, its magnetic characteristics and
And the coercive force after magnetization_IH_c(Magnetization length I = 0) decreased
It becomes a tendency. However, the residual magnetic flux density Br and the coercive force _B
H_c(Magnetic flux density B = 0) is almost unchanged, so
The large magnetic energy product (BH) max is substantially constant.

The brazing filler metal 20 must exhibit a bonding force at a heating temperature T that does not deteriorate the magnetic characteristics of the permanent magnet 15 containing a rare earth element as described above, that is, T ≦ 650 ° C. Further, this bonding force is exhibited due to its diffusivity when the brazing filler metal 20 is in a solid phase state under heating, and on the other hand, when the brazing filler metal 20 is in a liquid phase state or a solid-liquid coexisting state. It is necessary to be expressed by wettability.

From this point of view, as the brazing filler metal 20, a highly active one composed of a rare earth element type alloy is used.

The rare earth elements in this rare earth alloy are Y, La, Ce, Pr, Nd, Sm, Eu and G.
At least one selected from d, Tb, Dy, Ho, Er, Tm, Yb and Lu corresponds to these, and these are simple substances,
Alternatively, they are used in the form of a mixture of Mm (Misch metal) and Di (didymium). Further, the alloying element AE causes a eutectic reaction with a rare earth element, and the alloying element AE includes Cu, Al, Ga, Co, Fe, Ag, Ni and A.
u, Mn, Zn, Pd, Sn, Sb, Pb, Bi, Ge
And at least one selected from In is applicable.
The content of the alloy element AE is set to 5 atomic% ≦ AE ≦ 50 atomic%. When two or more kinds of alloying elements AE are contained, their total content is 5 atomic% ≤ AE ≤ 50 atomic%
Becomes However, if the content of the alloy element AE is AE> 50 atomic%, the activity of the rare earth element-based alloy is impaired, while
When it is <5 atomic%, it becomes difficult to secure a liquid phase in a solid-liquid coexisting state.

Table 1 shows examples of eutectic alloys in rare earth element alloys.

[0041]

[Table 1]

Sub- and hypereutectic crystals in rare earth element-based alloys
The following may be mentioned as alloys. Each chemistry
In the formula, the unit of numerical value is atomic%, which
The same. (A) Nd₆₀Cu₄₀Alloy, Nd₇₅Cu_{twenty five}Alloy, Nd₈₀
Cu₂₀Alloy, Nd₅₀Cu ₅₀Alloy: Liquid phase generation temperature 520
℃ (See Figure 8) (b) Sm₇₅Cu_{twenty five}Alloy, Sm₆₅Cu₃₅Alloy ... Liquid phase
Generation temperature 597 ° C (c) Nd₉₀Al_TenAlloy (liquid phase generation temperature 634 ° C),
Nd₈₀Co₂₀Alloy (liquid phase generation temperature 599 ℃), La₈₅G
a_FifteenAlloy (liquid phase generation temperature 550 ° C) Further, as a ternary alloy, Nd₆₅Fe_FiveCu₃₀alloy
(Liquid phase generation temperature 501 ° C) and Nd₇₀Cu_{twenty five}Al_FiveCombination
Gold (liquid phase generation temperature 474 ° C.) can be mentioned.

If the heating time h in the joining process of the magnet unit 4 is too long, it will affect the characteristics of the pedestal 13 and the permanent magnet 15, so that h ≦ 10 hours is desirable, and productivity is improved. From the viewpoint, h ≦ 1 hour.

The permanent magnets 2 are magnetized after the magnet units 4 are attached to the rotor body 3.

Hereinafter, a specific manufacturing example of the rotor 1 will be described.

As shown in FIGS. 1 and 6, the rotor body 3 is formed by laminating a plurality of circular cold-rolled steel plates 2 having a thickness of 0.4 mm, an outer diameter of 136 mm, a length of 100 mm, and a dovetail groove. The number of 12 is 12, and the opening width d of the dovetail groove 12 is d = 2.
2 mm, the bottom width e was e = 30 mm, the depth f was f = 5 mm, the length g in the generatrix direction was g = 100 mm, and the rotor shaft 6 was prepared.

As shown in FIG. 5, the pedestal 13 is formed by laminating dovetail cold-rolled steel sheets 16 having a thickness of 0.4 mm, and the short parallel side length h is h = 21.8 mm and the long parallel side. Length k
Is k = 29.8 mm, height m is m = 4.9 mm, length n is n
= 100 mm was prepared.

As the brazing material 20, a foil brazing material made of Nd ₇₀ Cu ₂₅ Al ₅ alloy and having a length of 100 mm, a width of 22 mm and a thickness of 0.1 mm was prepared.

The permanent magnet 15 has a length of 100 mm and a width of 22.
mm, 6 mm thick NdFeB-based permanent magnet (Sumitomo Special Metals Co., Ltd., trade name NEOMAX-28UH, Curie point 310)
℃) was selected.

As shown in FIGS. 5 and 7 (a), the foil-shaped brazing material 20 is superposed on the upwardly facing joining surface 19 of the pedestal 13, and the permanent magnet 15 and the joining surface 18 thereof are placed on the brazing material 20. The stack 21 was prepared by stacking the stacks facing downward, and a total of 12 stacks 21 were prepared by the same procedure. After that, the whole stack 21 is placed in a vacuum heating furnace,
A permanent magnet 15 was bonded to the pedestal 13 through the bonding layer 14 as shown in FIG. 3 by performing a bonding process of heating temperature T = 530 ° C. and heating time h = 15 minutes, followed by furnace cooling. The magnet unit 4 was obtained. In this joining process, the heating temperature T was 530 ° C.
Since the liquid phase generation temperature of 0, which is 474 ° C., is exceeded, the brazing material 20 is in a liquid phase state.

In these magnet units 4, a gap b exists between all the adjacent steel plates 16, and the average length b ₁ between the leading edges of the steel plates 16 in the gap b is about 4 μm. there were. Further, no crack was generated in the permanent magnet 15 in each magnet unit 4.

As shown in FIG. 6, the pedestal 13 of each magnet unit 4 was fitted into each dovetail groove 12 of the rotor body 3 to obtain the rotor 1.

In order to examine the heat resistance of the rotor 1, the rotor 1
Was placed in a heating furnace, heated at 150 ° C. for 1 hour and then cooled at room temperature, and no cracks were generated in each permanent magnet 15.

In the rotor 1, it is 1000
The permanent magnets 15 did not fall off from the rotor body 3 even at high speeds above 0 rpm.

Further, in order to check the yield of the rotor 1,
When 1200 magnet units 4 were manufactured so as to correspond to 100 rotors 1, defective joining occurred in the three magnet units 4.

From this, the yield R of the magnet unit 4 is
Is R = {(1200-3) / 1200} × 100≈9
It was found to be 9.8%, and thus the yield of the rotor 1 can be greatly improved.

[0057]

EFFECTS OF THE INVENTION According to the present invention, by virtue of the above construction, even if the rotor temperature rises due to the operation of the rotating machine, the bonding strength of each permanent magnet is not impaired, and each permanent magnet is It is possible to provide a rotor for a rotating machine having high reliability with respect to the joint structure of.

Further, according to the present invention, it is possible to provide a manufacturing method capable of improving the productivity and the yield of the rotor for a rotary machine by adopting the above-mentioned specific means.

Further, according to the present invention, the above-mentioned structure contributes to the improvement of the productivity of the rotor for the rotating machine, and can prevent the permanent magnet from cracking due to the rise and fall of the rotor temperature. Units can be provided.

[Brief description of drawings]

1 is a cross-sectional view showing an example of a rotor and corresponds to a cross-sectional view taken along line 1-1 of FIG.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a perspective view of a magnet unit.

FIG. 4 is a cross-sectional view illustrating the structure of a magnet unit.

FIG. 5 is a perspective view showing how to lay a permanent magnet and a brazing material on a pedestal.

FIG. 6 is a perspective view showing how to attach a magnet unit to a rotor body.

FIG. 7 is a cross-sectional view for explaining a heating and joining mechanism.

FIG. 8 shows a main part of an Nd—Cu phase diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotor 3 rotor body 4 magnet unit 13 pedestal 14 joining layer 15 permanent magnet 16 steel plate 20 brazing material 21 superposed product a steel plate laminating direction b gap

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 22, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

In the rotor 1, as the rotor temperature rises and falls, thermal stress concentrates on both ends of the pedestal 13 in the steel sheet laminating direction a. According to the above-mentioned structure, since the gap b exists between the steel plates 16 adjacent to each other on the both end sides, expansion and contraction of the steel plates 16 are absorbed by the gap b ,
As a result, the thermal stress on both end sides can be relaxed and the occurrence of cracks in each permanent magnet 15 can be avoided.

Claims (14)

[Claims] 1. A rotor body (3) and a plurality of magnet units (4) attached to the outer periphery of the rotor body (3), each magnet unit (4) being the rotor body (3). And a permanent magnet (15) joined to the pedestal (13) under heating via a joining layer (14) made of a brazing filler metal (20). A characteristic rotor for rotating machines. 2. The rotor for a rotating machine according to claim 1, wherein the brazing material (20) is made of a rare earth element alloy. 3. The brazing material (20) comprises Cu, Al, Ga, Co, Fe, Ag, Ni and A as alloy elements AE.
u, Mn, Zn, Pd, Sn, Sb, Pb, Bi, Ge
And at least one selected from In and 5 atomic% ≦
The rotor for a rotary machine according to claim 2, wherein the rotor contains AE ≦ 50 atomic%. 4. The rotor for a rotating machine according to claim 1, wherein the permanent magnet (15) is a permanent magnet containing a rare earth element. 5. The pedestal (13) comprises a plurality of steel plates (16).
The rotor for a rotating machine according to claim 1, 2, 3 or 4, wherein the rotor is laminated. 6. A plurality of superposed products (2) with a brazing material (20) interposed between a permanent magnet (15) and a pedestal (13).
1) and the heating of the superposed product (21) to join the permanent magnet (15) and the pedestal (13) through the joining layer (14) made of the brazing material (20). A rotating machine comprising: a step of obtaining a plurality of magnet units (4); and a step of attaching each magnet unit (4) to an outer peripheral portion of a rotor body (3) via its pedestal (13). Rotor manufacturing method. 7. The method of manufacturing a rotor for a rotating machine according to claim 6, wherein the brazing filler metal (20) is made of a rare earth element-based alloy. 8. The brazing material (20) comprises Cu, Al, Ga, Co, Fe, Ag, Ni and A as alloy elements AE.
u, Mn, Zn, Pd, Sn, Sb, Pb, Bi, Ge
And at least one selected from In and 5 atomic% ≦
The method for manufacturing a rotor for a rotating machine according to claim 7, wherein AE ≦ 50 atomic% is contained. 9. The method for manufacturing a rotor for a rotating machine according to claim 6, 7 or 8, wherein the permanent magnet (15) is a permanent magnet containing a rare earth element. 10. The pedestal (13) comprises a plurality of steel plates (1).
The method for manufacturing a rotor for a rotating machine according to claim 6, 7, 8 or 9, which is formed by stacking 6). 11. A pedestal (13) formed by laminating a plurality of steel plates (16) and joined to the pedestal (13) under heating through a joining layer (14) made of a brazing material (20). A permanent magnet (15), and a gap (b) generated by heating and joining between adjacent steel plates (16) at least on both ends of the pedestal (13) in the steel plate laminating direction (a).
There is a magnet unit. 12. The magnet unit according to claim 11, wherein the brazing material (20) is made of a rare earth element-based alloy. 13. The brazing material (20) is made of an alloy element AE.
As Cu, Al, Ga, Co, Fe, Ag, Ni, A
u, Mn, Zn, Pd, Sn, Sb, Pb, Bi, Ge
And at least one selected from In and 5 atomic% ≦
The magnet unit according to claim 12, containing AE ≤ 50 atomic%. 14. The permanent magnet (15) according to claim 11, 12 or 1, wherein the permanent magnet (15) is a permanent magnet containing a rare earth element.
3. The magnet unit described in 3.