JPS59130409A - Laminated core - Google Patents

Abstract

PURPOSE:To obtain a laminated core which has a high rigidity and is prevented from being deteriorated in the magnetic characteristics, by laminating silicon steel sheets larger in thickness tnan thin amorphous steel sheets, and setting the proportion in sectional area of the silicon steel sheets to the entire sectional area at a specific value. CONSTITUTION:Packets 4 are fixed by being tightened at their outer peripheral portions with an insulating tape 7. The core of each packet 4 is constituted by a laminated magnetic core 5 which is formed by laminating as a main body a mlutiplicity of thin amorphous steel sheets 3 as an amorphous magnetic material. As a reinforcing magnetic core, a predetermined number of silicon steel sheets 6 larger in thickness than the thin amorphous steel sheets 3 are combined and laminated on each of side surfaces of each laminated magnetic core 5 such as to cover the whole of the corresponding side surface of the magnetic core 5. The reinforcing magnetic cores constitued by the laminated silicon steel sheets 6 are laminated such as to cover a sectional area which amounts to 10% or less of the entire sectional area of the laminated core. Thus, as a compared with a laminated core constituted only by the thin amorphous steel sheets 3, the iron loss is increased about 10%, but the core rigidity is improved about ten times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a laminated iron core formed by laminating amorphous magnetic metal plates.

[Technical background of the invention and its problems]

Generally, in order to reduce eddy current loss with respect to the main magnetic flux, a laminated iron core in which strip steel plates are laminated is often used as an iron core used in a transformer.

However, in recent years, amorphous magnetic materials with extremely low iron loss have been developed and are now being put into practical use as iron cores for electrical equipment. This amorphous magnetic material for the iron core is a thin steel plate manufactured into a strip with a thickness of about 10 to 1000 μm by rapid cooling and ultra-high speed winding, and has a hardness of Vickers hardness Hv = 100.
It is a brittle material with a high resistance value of 0. Furthermore, this amorphous magnetic material has a high strain sensitivity during rapid cooling, and if left as it is, the magnetization characteristics will be extremely poor and the iron loss will increase. For this reason, when used, heat treatment is performed in a magnetic field in a non-oxidizing atmosphere after core processing to improve core loss magnetization characteristics.

However, when thin steel sheets, which are amorphous magnetic materials, undergo heat treatment in a magnetic field, if the surface of the material oxidizes, the magnetic properties will be lost and the material will deteriorate. Even small local stresses applied to the structure can cause cracks and lead to destruction. In other words, when constructing a laminated core using amorphous thin steel sheets,
If the structure is not designed in consideration of the above phenomenon, fatigue failure may occur due to local stress applied during the core manufacturing process or electromagnetic vibration during transformer operation.

Therefore, in a laminated core constructed by laminating these amorphous thin steel plates, in addition to measures to obtain the necessary magnetic properties, measures are required to protect the core by providing it with high rigidity capable of withstanding stress.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and provides high rigidity to an amorphous thin steel plate to prevent the material from breaking due to stress, and prevents deterioration of magnetic properties while increasing the rigidity. It provides a laminated iron core.

[Summary of the invention]

The laminated core of the present invention has a laminated magnetic core formed by laminating thin steel plates made of an amorphous magnetic material, and is laminated with a thick silicon steel plate in addition to the amorphous thin steel plate to increase the rigidity. In consideration of the improvement in core rigidity and the deterioration of core loss due to lamination of steel plates, the proportion of the cross-sectional area of silicon steel plates is set within 10 inches of the total area of the core.

[Embodiments of the invention]

Embodiments of the present invention illustrated in the drawings will be described below.

FIG. 1 shows a schematic configuration of an iron core used in a single-phase transformer as an example of a laminated iron core. This laminated core is made up of two sets of yoke cores 1 and leg cores 2 which are alternately lap-bonded and assembled into a rectangular frame shape. The yoke core 1 and the leg core 2 are each manufactured by punching and forming an amorphous thin steel plate 3, which is an amorphous magnetic material, into a predetermined shape, and then stacking and fixing a large number of these amorphous steel plates 3. ing.

FIG. 2 shows a cross section of a laminated core shown in FIG. 1 having a stepped laminated structure as an embodiment of the present invention. Here, numerals 4 in the figure are packets stacked in a stepwise manner with the width dimension gradually decreasing, and these packets 4 are fixed by tightening the outer periphery with an insulating tape 7. 74 in the center
Taking the case 4 as an example, the core structure of Shibakerat will be described. In the figure, 5 is a laminated magnetic core formed by laminating a large number of amorphous thin steel plates 3, which are amorphous magnetic materials, as a main body.

In the figure, reference numeral 6 denotes a silicon steel plate which is not made of a normal melted material and has a thickness greater than that of the amorphous thin steel plate 3. A predetermined number of silicon steel plates 6 are placed on both side surfaces of the laminated magnetic core 5 as reinforcing magnetic cores. are laminated in combination to cover both sides of the laminated magnetic core 5. Other packets 4 are constructed in the same manner.

In such an iron core structure, the core rigidity of the laminated magnetic core 5 in which the amorphous thin steel plates 3 are laminated is improved by laminating the silicon steel plates 6, which are thicker than the amorphous thin steel plates 3. That is, the rigidity F of the iron core composed of the laminated magnetic core 5 and the silicon steel plate 6 is
is expressed as the product of the longitudinal elastic modulus E and the moment of inertia of the material constituting the core. That is, F=E, I
Engineering + E2I2.

However, El: Modulus of longitudinal elasticity of the laminated magnetic core 5 1: Moment of inertia of area of the laminated magnetic core 5 E2 = Coefficient of longitudinal elasticity of the silicon steel plate 6 2: Moment of inertia of area of the silicon steel plate 6.

The longitudinal section coefficients EllE2 of the laminated magnetic core 5 and the silicon steel plate 6 are approximately the same value (1.5 x 10' = 9/m2).

Therefore, the rigidity of the core can be calculated from the ratio of the moment of inertia of each section of the laminated magnetic core 5 and the silicon steel plate 6 to the total cross-sectional area of the core, that is, the ratio of the size of each section. The individual moment of inertia of each non-magnetic thin steel plate 3 of the laminated magnetic core 5 and the moment of inertia of each silicon steel plate 6 are proportional to the cube of the plate thickness t, where plate width b1 plate thickness t. So I=bt
Since it is expressed as 3/12, the number of amorphous thin steel plates 3'k
nt and the number of silicon steel plates 6 is n2, the rigidity F of the iron core is approximated by:

However, tl is the plate thickness of the amorphous thin steel plate 3, and t2 is the plate thickness of the silicon steel plate 6. For example, the thickness tl of the amorphous thin steel plate 3 is 30 μm1
The plate thickness t2 of the plain steel plate 6 is 300 mm.

Here, the ratio of the cross-sectional area of the silicon steel plate 6 to the total cross-sectional area of the iron core is n2'''t2 ''nl, tl+.2..2X100 (chi) ---
----------- Song (2).

Figure 3 is a diagram showing the relationship between the stiffness F of the iron core and the ratio y of the cross-sectional area of the silicon steel fracture 6 to the total cross-sectional area of the iron core, according to equations (1) and (2). The core stiffness F is set to 1 when an amorphous thin steel plate is used. Figure 3: Ratio of the cross-sectional area of silicon steel plate 6 to the total cross-sectional area of the iron core i10
%, it can be seen that the core rigidity increases approximately 10 times.

By laminating a small number of bare steel plates 6 on the laminated magnetic core 5 in this manner, the core rigidity is significantly improved.

Next, changes in iron loss in the core due to lamination of the silicon steel plates 6 on the laminated magnetic core 5 will be explained. In general, amorphous thin steel sheets have a low saturation magnetic flux density of about 1.6T, so the iron core is used with a rated magnetic flux density of about 1.3T.

The iron loss at a magnetic flux density of 1.3T is approximately 0.20WA. When the silicon steel plate 6 is excited with the magnetizing force to obtain this magnetic flux density of 1.3 T 'i, the magnetic flux density of the silicon steel plate 6 is approximately 1.5 T, and the iron loss is 0.45 w/kI? It is. Figure 3 shows the iron loss value W calculated using the above value from the cross-sectional area ratio y of the silicon steel plate 6 to the total cross-sectional area of the core.
is also listed. As shown in Figure 3, even if the cross-sectional area of the silicon steel plates 6 in the total area of the core is 10 mm, the iron loss is only about 1.1 times at most, which is small. Characteristics are put to good use. Moreover, this value is the degree of variation in magnetic properties due to differences in heat treatment conditions.

In this way, in the core configuration according to the present invention, the amorphous thin steel plate 3
When a laminated magnetic core is constructed only from amorphous thin steel plates 3 by laminating a reinforcing magnetic core made by laminating silicon steel plates 6 on a laminated magnetic core 5 with a cross-sectional area within 10% of the total cross-sectional area of the core. The iron loss increases by about 1096, but the core rigidity improves by about 10 times. Therefore, it is possible to obtain a laminated core that has sufficient strength against stress during core assembly and electromagnetic vibration during transformer operation.

Furthermore, in the embodiment shown in FIG. 2, each step (the stepped portion 8 of the kerato 4 receives stress concentration due to the tightening force, but this portion is protected by the silicon steel plate 6). Therefore, stress concentration on the laminated magnetic core 5 is alleviated.

This makes the core highly reliable in terms of strength. Furthermore, when the entire packets of each stage are bound with the insulation chip f7 around the outer periphery, there is a concern that cracks may occur at the ends of the laminated magnetic core 5 due to the tightening force, but in this configuration, all of these contact parts are made of silicon. Since it is protected by the steel plate 6, this effect is reduced.

FIG. 4 shows a cross section of a laminated core in another embodiment of the present invention. In this case, the core cross section is rectangular. In this embodiment, silicon steel plates 6 are dispersed and laminated as reinforcing magnetic cores on both side surfaces and inside the entire laminated magnetic core 5. The ratio of the cross-sectional area of the reinforcing magnetic core formed by laminating the single-layer steel plates 6 to the total core area is within 10%.

Also in this embodiment, the core rigidity can be significantly improved without impairing the core loss characteristics.

〔Effect of the invention〕

As explained above, the laminated core of the present invention can significantly improve the core rigidity without completely impairing the core loss characteristics of the core made by laminating amorphous thin steel plates, and the core can be damaged by external stress during core processing or use. can be prevented.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an example of a laminated core, Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1, and Fig. 3 is a cross-sectional view showing an embodiment of the present invention. FIG. 4 shows another embodiment of the present invention, and is a cross-sectional view taken along line A-A in FIG. 1. DESCRIPTION OF SYMBOLS 1... Yoke core, 2... Leg core, 3... Amorphous thin steel plate, 4... Packet, 5... Laminated magnetic core, 6... Silicon steel plate, 7... Insulation tape. Applicant's representative Patent attorney Takehiko Suzue 1 Figure 3 Figure 2 183 Figure Y ('/11) 1B4 Figure 58.19 Showa year month - Chief of the Japan Patent Office Kazuo Wakasugi 1, Patent application for indication of the case No. 58-5469 No. 2, Name of the invention Laminated core 3, Relationship with the case of the person making the amendment Patent applicant (307) Toshibaura Electric Co., Ltd. 4, Attorney's specification, drawings --m- 7, Contents of the amendment 2% fil On page 6, line 9 of the specification, the statement was corrected to ``about 1.2 times,'' and on line 15 of the same page, it was changed to ``approximately 1.2 times.''
About 10%] Correct it to ``about 20%.''

Claims (1)

[Claims] A thicker silicon steel plate than the amorphous magnetic thin steel plate is laminated on a laminated magnetic core formed by laminating amorphous magnetic thin steel plates, and the ratio of the cross-sectional area of the laminated silicon steel plate to the entire core is 10 of cross-sectional area
A laminated iron core characterized by being set within %.