JPH11186059A - Low-loss laminated iron core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve magnetic characteristic of a laminated iron core by reducing the iron loss of the core, by only forming welds on the outer peripheries of a plurality of nonoriented silicon steel sheets laminated upon another. SOLUTION: An iron core 1 is formed by laminating a plurality of non- oriented silicon steel sheets punched in a prescribed shape upon another. At the time of fixing the laminated core 1 by welding, welds 3 are only formed on the outer periphery of the core 1 where the magnetic path becomes the maximum. It is preferable to adjust Si content of the steel sheets constituting the core 1 to set to 4-7 wt.% and to punch the steel sheets in a U-shape. Consequently, a low-loss laminated iron core having a superior magnetic characteristic can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-loss laminated core suitable for transformers and reactors.

[0002]

2. Description of the Related Art As iron cores for transformers and reactors, wound iron cores or laminated iron cores made of silicon steel sheets have been widely used mainly in the field of electric power. The wound iron core is an iron core formed by winding a single silicon steel sheet in a plurality of layers, and a directional silicon steel sheet that is advantageous in terms of iron loss characteristics is generally used because it is used by being excited in the winding direction.

On the other hand, a laminated iron core is an iron core obtained by laminating a plurality of silicon steel sheets punched into an EI type or EE type or another desired shape, and mainly uses a non-oriented silicon steel sheet. The reason is that, in the case of a grain oriented silicon steel sheet, it is disadvantageous because it is excited not only in the longitudinal direction of the silicon steel sheet coil but also in the C direction where iron loss is significantly deteriorated.

[0004] In terms of iron loss characteristics, wound iron cores are generally superior to laminated iron cores. However, wound iron cores require a large number of manufacturing steps as compared with laminated iron cores, so that the manufacturing cost is significantly increased. Further, non-oriented silicon steel sheets used for laminated iron cores are generally less expensive than oriented silicon steel sheets used for wound iron cores. Therefore, in applications requiring low cost, a laminated iron core is mainly used.

[0005]

As means for fixing a plurality of laminated silicon steel sheets in a laminated iron core made of non-oriented silicon steel sheets, a method of impregnating with resin, fixing by bolting, welding, And the like.

Among them, the method of fixing by welding is as follows.
The manufacturing process can be simplified and automated, and the manufacturing cost can be reduced. However, on the other hand, there is a problem that the magnetic characteristics are significantly deteriorated, such as an increase in iron loss of the iron core.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and reduce iron loss of an iron core when laminating iron cores made of non-oriented silicon steel sheets and fixing them by welding to form a laminated iron core. An object of the present invention is to provide a low-loss laminated core that is excellent in magnetic properties and can be manufactured at low cost and is suitable for transformers and reactors.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems and to develop a low-loss laminated core having extremely small core loss and excellent magnetic properties.
As a result, they have found that if the welding position when a plurality of laminated non-oriented silicon steel sheets are laminated and fixed by welding is only on the outer peripheral side of the iron core, iron loss of the iron core can be extremely reduced.

The present invention has been made on the basis of the above findings. According to the first aspect of the present invention, a plurality of non-oriented silicon steel sheets punched into a predetermined shape are laminated and fixed by welding. In the laminated iron core formed as described above, the position of the welded portion is characterized only on the outer peripheral side of the plurality of laminated non-oriented silicon steel sheets.

The invention according to claim 2 is characterized in that the plurality of non-oriented silicon steel sheets to be laminated are high silicon steel sheets containing 4 to 7 wt.% Of Si,
The invention described in claim 3 is characterized in that the punched shape of the plurality of non-oriented silicon steel sheets to be laminated is a U-shape.

[0011]

Next, the present invention will be described with reference to the drawings. 1 and 2 are plan views showing one embodiment of a low-noise laminated core according to the present invention. FIG.
FIG. 2 shows an EI-type iron core 1 in which a plurality of non-oriented silicon steel sheets punched in a U-shape are laminated, and FIG. 2 shows a U-shaped iron core 2 in which a plurality of non-directional silicon steel sheets punched in a U-shape are stacked. Show.

In the present invention, the laminated EI
When fixing the mold core 1 or the U-shaped iron core 2 by welding, the position of the welded portion 3 is set only on the outer peripheral side of the iron core where the magnetic path is the largest. Thus, by setting the welded portion 3 only on the outer peripheral side of the iron core, the iron loss of the iron core can be extremely reduced.

On the other hand, as shown in FIGS. 3 and 4, the positions of the welded portions 3 of the EI-type core 1 'and the U-type core 2' in which a plurality of non-oriented silicon steel sheets are laminated are defined by the outer circumference of the iron core. In the case of the inner side and the inner side, since the inner side of the iron core through which the magnetic flux easily flows becomes conductive, the iron loss increases.

The non-oriented silicon steel sheet constituting the iron core preferably has a Si content of 4 to 7 wt.%. The purpose of using high silicon steel sheet as the material of the iron core is to reduce the iron loss at high frequency. However, if the Si content is less than 4 wt.%, The iron loss at high frequency increases significantly and the advantage of using high silicon steel sheet is high. Is not exhibited. On the other hand, when the Si content exceeds 7 wt.%, The steel sheet is easily embrittled and punching becomes difficult.

The punched shape of the laminated non-oriented silicon steel sheet is preferably U-shaped. By making the punched shape U-shaped, the effect of reducing iron loss can be further enhanced.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. [Example 1] A sheet thickness of 0.35 mm and substantially 3 wt.
Ten sets of EI-type laminated iron cores were prepared by punching out and laminating a non-oriented silicon steel sheet containing i to the FEI 40 size described in JIS C 2514. As shown in FIG. 1, 5 sets of these 10 sets of iron cores are welded only on the outer peripheral side of the iron core 1 to form a welded portion 3, and the remaining 5 sets of iron cores 1 ′ as shown in FIG. Were welded on the inner and outer peripheral sides to form a welded portion 3.

The laminated core 1 in which the welded portion 3 is formed only on the outer peripheral side and the laminated core 1 ′ in which the welded portion 3 is formed on the inner peripheral side and the outer peripheral side are subjected to a frequency 400H.
The core loss was measured when the magnetic field was excited at z and the magnetic flux density was 0.5 T. The measurement results are shown in Table 1, and the average of the five samples is shown in FIG.

[0018]

[Table 1]

As is clear from Table 1 and FIG. 5, the iron loss value in the case of the present invention in which the welded portion is only the outer peripheral side of the iron core is 9.3 to 10.8 W / Kg (average value 9.8 W). / K
g), on the other hand, the iron loss value of the comparative example in which the welded portion was the inner peripheral side and the outer peripheral side of the iron core was 12.7 to 14.7.
W / Kg (average value 13.5 W / Kg), and in the case of the present invention example in which the welded portion was only on the outer peripheral side of the iron core, the iron loss could be suppressed low. [Embodiment 2] The thickness of S is substantially 3 wt.
Ten sets of U-shaped laminated iron cores were prepared by punching out a non-oriented silicon steel sheet containing i into a U-shape so as to have the same size as CS25 size specified in the standards of the Japan Winding Core Industry Association and laminating them. As shown in FIG. 2, 5 sets of these 10 sets of cores are welded on the outer peripheral side of the core 2 to form a welded portion 3, and the remaining 5 sets are formed as shown in FIG.
Welding is performed on the inner and outer peripheral sides of the iron core 2 by welding.
And

The core loss was measured when the laminated core thus formed was excited at a frequency of 400 Hz and a magnetic flux density of 0.5 T. The measurement results are shown in Table 2, and the average of each of the five samples was calculated. As shown in FIG.

[0021]

[Table 2]

As is clear from Table 2 and FIG. 6, the iron loss value in the case of the present invention in which only the outer peripheral side of the iron core is welded is:
The iron loss value in the case of the comparative example in which the inner peripheral side and the outer peripheral side of the iron core were welded was 13.8 to 15, whereas the average value was 9.0 to 9.6 W / Kg (average value: 9.2 W / Kg). .6W / Kg
(Average value 14.5 W / Kg), and in the case of the present invention example in which the welding position was only the outer peripheral side of the iron core, the iron loss could be reduced.

FIG. 5 shows the iron loss value when the EI type laminated core of Example 1 is used, and FIG. 6 which shows the iron loss value when the U-shaped laminated core of the example of the present invention is used. As is clear from comparison, when the U-shaped laminated iron core of this example was used, the effect of reducing the iron loss value was even more remarkable. [Example 3] A high silicon steel sheet having a thickness of 0.1 mm and substantially containing 6.5 wt.% Of Si was subjected to FE described in JISC 2514.
Ten sets of EI type laminated cores punched and laminated to I40 size were prepared. As shown in FIG. 1, five sets of these ten sets of iron cores are welded on the outer peripheral side of the iron core 1 to form a welded portion 3, and the remaining five sets are formed as shown in FIG. 3.
The inner and outer peripheral sides of the iron core 1 ′ were welded to form a weld 3.

The core loss was measured when the laminated iron core thus formed was excited at a frequency of 10 KHz and a magnetic flux density of 0.1 T. The measurement results are shown in Table 3, and the average of each of the five samples was calculated. As shown in FIG.

[0025]

[Table 3]

As is clear from Table 3 and FIG. 7, the iron loss value in the case of the present invention in which only the outer peripheral side of the iron core is welded is:
The iron loss value in the case of the comparative example in which the inner peripheral side and the outer peripheral side of the iron core were welded was 16.7 to 18, whereas the average value was 9.1 to 10.1 W / Kg (average value: 9.6 W / Kg). .3W / Kg
(Average value of 17.5 W / Kg), and in the case of the present invention example in which the welding position was only the outer peripheral side of the iron core, the iron loss could be suppressed low.

FIG. 5 shows iron loss values when the EI type laminated core made of the non-oriented silicon steel sheet of Example 1 is used.
As is apparent from a comparison between FIG. 7 showing the iron loss value when the EI type laminated core made of the high silicon steel sheet of the present invention is used, the laminated core made of the high silicon steel sheet of this example is used. In this case, the effect of reducing the iron loss value was even more remarkable. [Example 4] A high silicon steel sheet having a thickness of 0.1 mm and substantially containing 6.5 wt.% Of Si was made to have the same dimensions as the CS25 size specified in the standards of the Japan Core Industry Association. The U-shaped laminated iron core punched and laminated into a U-shape
A set was prepared. Five of these 10 iron cores are
As shown in FIG. 4, only the outer peripheral side of the iron core 2 is welded to form a welded portion 3, and the remaining five sets are welded on the inner peripheral side and the outer peripheral side of the iron core 2 'as shown in FIG. 3

The core loss when the laminated core thus formed was excited at a frequency of 10 KHz and a magnetic flux density of 0.1 T was measured. The measurement results are shown in Table 4, and the average of the five samples was calculated. As shown in FIG.

[0029]

[Table 4]

As is apparent from Table 4 and FIG. 8, the iron loss value in the case of the present invention in which only the outer peripheral side of the iron core is welded is:
In contrast to 8.6 to 9.2 W / Kg (average value of 8.9 W / Kg), the iron loss value of the comparative example in which the inner and outer peripheries of the iron core were welded was 18.8 to 21.5 W / Kg. (Average value 19.5
W / Kg), and in the case of the present invention example in which the welding position was only the outer peripheral side of the iron core, the iron loss was able to be suppressed low.

The EI made of the high silicon steel sheet of Example 3
FIG. 7 showing the iron loss value when using the laminated iron core of the present invention and FIG. 8 showing the iron loss value when using the laminated U-shaped iron core made of the high silicon steel sheet of the present invention are apparent. In addition, when the U-shaped laminated core made of the high silicon steel sheet of this example was used, the effect of reducing the iron loss value was even more remarkable.

[0032]

As described above, according to the present invention,
When cores made of non-oriented silicon steel sheets are laminated and fixed by welding to form a laminated core, iron loss of the core is small,
An industrially useful effect of obtaining a low-loss laminated iron core having excellent magnetic properties, having excellent iron loss characteristics, low noise, excellent mass productivity, and low cost can be produced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an example of a laminated iron core of the present invention in which a plurality of non-oriented silicon steel sheets punched into an EI shape are laminated, and only the outer peripheral side is welded.

FIG. 2 is a schematic plan view showing another example of the laminated core of the present invention in which a plurality of non-oriented silicon steel sheets punched in a U-shape are laminated, and only the outer peripheral side is welded.

FIG. 3 is a schematic plan view showing a comparative example of a laminated core obtained by laminating a plurality of non-oriented silicon steel sheets punched into an EI shape and welding the inner and outer peripheral sides thereof.

FIG. 4 is a schematic plan view showing a comparative example of a laminated core obtained by laminating a plurality of non-oriented silicon steel sheets punched in a U-shape and welding inner and outer peripheral sides thereof.

FIG. 5 is a graph showing an iron loss value when the laminated core of Example 1 is excited, in comparison with a comparative example.

FIG. 6 is a graph showing an iron loss value when the laminated core of Example 2 is excited, in comparison with a comparative example.

FIG. 7 is a graph showing an iron loss value when the laminated core of Example 3 is excited, in comparison with a comparative example.

FIG. 8 is a graph showing an iron loss value when the laminated core of Example 4 is excited, in comparison with a comparative example.

[Explanation of symbols]

 Reference Signs List 1 EI type laminated core 2 U type laminated core 3 Welded part

Claims (3)

[Claims] In a laminated iron core formed by laminating a plurality of non-oriented silicon steel sheets punched into a predetermined shape and fixing them by welding, the position of a welded part is determined by the plurality of laminated non-oriented silicon steel sheets. A low-loss laminated iron core characterized by being provided only on the outer peripheral side of a grain-oriented silicon steel sheet. 2. The plurality of non-oriented silicon steel sheets to be laminated are high silicon steel sheets containing 4 to 7 wt.% Si.
The low-loss laminated core according to claim 1. 3. The punched shape of the plurality of non-oriented silicon steel sheets to be stacked is a U-shape.
The low-loss laminated iron core according to 1.