CA-3153414-C - WOUND CORE

Abstract

A wound core equipped with a laminated body including plural electrical steel sheets stacked in a ring shape in side view. The laminated body includes plural bent portions, and plural block-shaped portions at positions between adjacent bent portions. At least one bent portion among the plural bent portions is a high stacking factor bent portion, wherein a stacking factor of the electrical steel sheets at the high stacking bent portion is higher than an average stacking factor of the steel sheets at the plural block-shaped portions.

Inventors

• Hisashi Mogi
• Takahito MIZUMURA
• Teruyuki Tamaki
• Hiroshi Fujimura
• Ryu Hirayama

Assignees

• NIPPON STEEL CORPORATION

Dates

Publication Date

20260505

Application Date

20200903

Priority Date

20190910

Claims (10)

1. CLAIMS 1. A wound core comprising: a laminated body including a plurality of electrical steel sheets stacked in a ring shape in side view; and a compression means, wherein: the laminated body includes a plurality of bent portions, and a plurality ofblockshaped portions at positions between adjacent bent portions; at least one bent portion among the plurality of bent portions is a high stacking factor bent portion, wherein a stacking factor of the electrical steel sheets at the high stacking bent portion is higher than an average stacking factor of the electrical steel sheets at the plurality of block-shaped portions; the compression means is configured to compress the plurality of electrical steel sheets at the high stacking factor bent portion in a stacking direction of the electrical steel sheets; and the high stacking factor bent portion is compressed at a pressure of from 0.2 MPa to 4.0MPa.
2. 2. The wound core of claim 1, wherein an average stacking factor A of the electrical steel sheets at the plurality of bent portions is (B - 4.0) % or greater, wherein Bis the average stacking factor(%) of the electrical steel sheets at the plurality of block-shaped portions.
3. 3. The wound core of claim 1 or 2, wherein the compression means includes: a first fixture disposed at an outer peripheral side of the high stacking factor bent portion and configured to abut the high stacking factor bent portion; a second fixture disposed at an inner peripheral side of the high stacking factor bent portion and configured to abut the high stacking factor bent portion; and a coupling part configured to couple the first fixture and the second fixture together, wherein the first fixture and the second fixture receive constraining force from the coupling part, and the plurality of electrical steel sheets at the high stacking factor bent portion are compressed in the electrical steel sheet stacking direction.
4. 4. The wound core of claim 3, wherein the first fixture and the second fixture are formed by a non-magnetic material, or the coupling part is formed by a non-magnetic material. 21 Date Rei;ue/Date Received 2024-04-12
5. 5. The wound core of claim 1 or 2, wherein: the wound core includes a pair of facing bent portions that face each other across a center of the laminated body, in side view; the facing bent portions are each high stacking factor bent portions; and the compression means includes a compression member configured to compress the facing bent portions across the center of the laminated body in side view.
6. 6. The wound core of claim 5, wherein: the compression member is a rod-shaped beam capable of extension-contraction adjustment that is disposed at an inner side of the laminated body and on a straight line connecting internal comer portions of the respective high stacking factor bent portions facing each other in side view, and, in an extended state, the compression member compresses the plurality of electrical steel sheets at the facing high stacking factor bent portions in the electrical steel sheet stacking direction.
7. 7. The wound core of claim 5 or 6, wherein the compression member is formed by a nonmagnetic material.
8. 8. The wound core of any one of claims 1 to 7, wherein a stacking factor C of the electrical steel sheets at the high stacking factor bent portion is greater than B% and less than or equal to (B+l)%, wherein Bis the average stacking factor(%) of the electrical steel sheets at the plurality of block-shaped portions.
9. 9. The wound core of claim 1, wherein all of the bent portions are high stacking factor bent portions.
10. 10. The wound core of any one of claims 1 to 9, wherein a shape of the laminated body when viewed from a side face is an octagonal shape including four of the block-shaped portions and four of the bent portions. 22 Date Rei;ue/Date Received 2024-04-12

Description

DESCRIPTION WOUND CORE Technical Field [0001] The present disclosure relates to a wound core. Background Art [0002] A wound core is employed as a magnetic core of a transformer, a reactor, a noise filter, and the like. Hitherto in transformers, the reduction of an iron loss has become an important issue from the perspective of high efficiency, and the reduction of an iron loss is researched from various perspectives. [0003] Moreover, transformers or the like employing wound cores are widely applicable to electrical and electronic devices. However, a wound core generates noise when a magnetic field is applied due to magnetostriction therefore noise reduction is actively being researched by reducing magnetostrtion. [0004] For example, a low noise winding transformer is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2017-84889. In this low noise winding transformer, an outer periphery of an iron core made from steel sheets in a coil shape, a circumferential direction band is wound in the steel sheet winding direction. A stacking band having a vibration loss coefficient of ri > 0.01 is arranged at the surface side of the circumferential band, between the core and a wound coil around the core. SUMMARY OF INVENTION Technical Problem [0005] Technology to reduce the iron loss of a wound core is known in which a wound core is made with plural electrical steel sheets. However, noise is liable to be generated due to magnetostriction to use the electrical steel sheets. Recently there are demands for even greater reductions in noise for wound cores by reduced magnetostriction. There is room for improvement in reducing wound core noise. [0006] An object of the present disclosure is to provide a wound core with reduced iron loss and the noise. Solution to Problem [0007] The authors of the present disclosure have researched diligent into reducing the wound core noise of, and have focused on gaps between stacked electrical steel sheets. When an alternative magnetic field is applied to a wound transformer core, electrical steel sheets vibrate in the stacking direction due to magnetostriction generated in the electrical steel sheets. An acoustic wave is generated by the vibration from the gaps between the electrical 1 Date Re9ue/Date Received 2022-03-04 steel sheets. This acoustic wave is perceived as a sound. The authors of the present disclosure have discovered that the bent portions make the gaps larger between the electrical steel sheets in the wound core, and the gaps at these bent portions have a large influence of the transformer noise. They have discovered that the smaller gaps at the bent portions are made, the lower the noise becomes, and as a result of further research have arrived at the present disclosure. [0008] The gist of an aspect of the present disclosure based on the above discoveries is described below. A wound core of an aspect of the present disclosure is equipped with a laminated body including plural electrical steel sheets stacked in a ring shape in side view. The laminated body includes plural bent portions, and plural edge portions at positions between adjacent bent portions. At least one bent portion among the plural bent portions possesses a high stacking factor, wherein the highest stacking factor of the electrical steel sheets at the bent portion is higher than an average stacking factor of the electrical steel sheets at the plural block-shaped portions. Advantageous Effects of Invention [0009] The present disclosure enables provision of a wound core with reduced iron loss and the noise. BRIEF DESCRIPTION OF DRAWINGS [0010] Fig. 1 is a side view illustrating an example of a wound core according to a first exemplary embodiment of the present disclosure. Fig. 2 is an exploded perspective view of a portion X in Fig. 1, and is a diagram illustrating an example of a compression means provided to a wound core according to a first exemplary embodiment. Fig. 3 is a schematic diagram illustrating a bent portion before and after application of a compression means. Fig. 4 is a side view illustrating an example of a wound core according to a second exemplary embodiment of the present disclosure. Fig. 5 is a graph illustrating a relationship between sound pressure and an average stacking factor of the electrical steel sheets at four bent portions of a Test Example. Fig. 6 is a graph illustrating a relationship between sound pressure and an average stacking factor of the electrical steel sheets at four bent portions in a Test Example. DESCRIPTION OF EMBODIMENTS 2 Date Re9ue/Date Received 2022-03-04 [0011] Detailed description follows regarding exemplary embodiments of the present disclosure, with reference to the appended drawings. Note that configuration elements having essentially the same functional configuration are appended with the same reference numerals in the present specification and drawings, and duplicate explanation thereof will be omitted. Moreover, the proportions and dimensions