JP2897384B2 - Electromagnetic device and method of manufacturing electromagnetic device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electromagnetic device such as a transformer, a method for manufacturing the same, and a resin material.

2. Description of the Related Art Conventional electromagnetic devices, such as transformers, have a method of preventing noise by applying paint to the end surface of an iron core or incorporating an iron core, and then taping a part where a coil is not wound to form a magnetic tape. Or a fastening member is used instead of the taping.

Hereinafter, a conventional method for preventing noise of a transformer will be described with reference to the drawings. FIG. 2 (a) is a schematic front view of a three-phase wound iron core main body portion, and FIG. 2 (b) is an enlarged view of a portion where electromagnetic steel plates are butted, that is, a portion A in FIG. 2 (a).

The magnetic steel sheet 21 is wound around a core and then formed to form inner iron cores 23 and 24. Similarly, an outer iron core 25 is formed, housed in a frame, and annealed by heating to a high temperature in an inert gas atmosphere. I do. After cooling it, the iron core is disassembled, this electromagnetic steel sheet is inserted into the concentrically arranged high-voltage coil and low-voltage coil, and iron core tightening brackets and coil fixing parts are attached to form a transformer. . As shown in FIG. 2 (b), the iron core manufactured in this manner has a gap 22 at the butted portion of the electromagnetic steel plates 21. The noise of the electromagnetic equipment is caused by the magnetostrictive vibration of the electromagnetic rope plate caused by the excitation and the electromagnetic vibration caused by the AC magnetic field as the vibration source. Conventional noise prevention methods include taping and tightening the yoke (the part where the electromagnetic coil is not wound) or using a tightening member, and applying paint to the end face to double as rust prevention. Noise was prevented by preventing vibration by such means. However, no consideration was given to the magnetic properties of the applied paint.

However, in the above-described conventional noise prevention method, although the noise can be reduced by 7 to 8 dB as compared with the case of no processing, the noise of the transformer is as high as 63 to 64 dB.

The present invention further seeks to provide arrangements, methods and materials that significantly reduce noise.

Means for Solving the Problems In order to achieve the above object, in an electromagnetic device according to the present invention, a resin mixed with magnetic particles is impregnated in a gap between a butt portion and a yoke portion of an electromagnetic iron core and cured. Further, the resin is cured in a magnetic field.

Action As described above, the resin containing the magnetic particles is impregnated into the gaps of the magnetic steel sheets and hardened to fix and integrate the magnetic steel sheets with each other, so that the vibration of the iron core is suppressed and the noise is significantly reduced. Further, by hardening the resin in a magnetic field, the magnetic particles mixed in the resin are oriented, and the magnetic resistance in the gap is reduced to reduce the loss.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a schematic front view of an electromagnetic iron core according to the present invention,
FIG. 2B is an enlarged view of a portion where the electromagnetic steel sheets are butted, that is, a portion A of FIG. 1A.

In the figure, reference numeral 1 denotes an electromagnetic steel sheet, and when low loss is required, a directional silicon steel sheet or the like is used. Reference numeral 2 denotes a resin mixed with magnetic particles such as ferrite and iron powder filled in the gap. As the magnetic particles, those having a particle size of 0.5 μm or less are excellent in consideration of the dispersibility with the resin and the like.
The mixing ratio is suitably about 1 to 60% by weight. This is a condition for selecting a resin that has sufficient heat resistance under the rated conditions of the transformer.
Since the temperature is around 100 ° C., those using an aliphatic amine as a curing agent with an epoxy resin can also be used. Magnetic steel sheet 1
In order to accelerate the impregnation between the layers, it is better to select a resin with a low viscosity.However, those with excellent impregnating properties are easy to flow out. It is good to cure in. Reference numerals 3 and 4 denote inner iron cores, 5 denotes an outer iron core, and 6 denotes a gap between the inner iron cores 3, 4 and the outer iron core 5. Numerals 7 and 8 are tapes wound for the purpose of noise reduction. If the gap between the magnetic steel sheets 1 is sufficiently filled with resin, the tapes 7 and 8 are unnecessary.

A prototype in which the iron core portion has been subjected to the noise prevention treatment of the present invention,
In the case of a three-phase 100 KVA dry transformer, the noise was 53 dB, showing a significant reduction effect.

(Reference) Resin: Cold-cured epoxy resin Iron powder mixed: 0.1 micron diameter Mixing ratio: 20% by weight (cured in a magnetic field) In the examples, the iron core of a three-phase transformer was described. The present invention is also applicable to electromagnetic devices having other electromagnetic iron cores.

Effect of the Invention As described above, the electromagnetic device of the present invention impregnates and cures the resin mixed with magnetic particles in the gaps of the electromagnetic steel sheets forming the electromagnetic iron core, and thus reduces the magnetic resistance of the gaps of the electromagnetic steel sheets. In addition, since they are integrated with resin, vibration is suppressed and noise is reduced. Further, after the resin is impregnated and cured in a DC magnetic field, there is no resin leakage from the gap, and the magnetic resistance of the gap is further reduced by the orientation of the magnetic particles, and the vibration energy is reduced. descend.

With the above effects, the noise level of the dry transformer can be significantly improved.

[Brief description of the drawings]

1 (a) and 1 (b) are schematic front views and enlarged views of main parts of an electromagnetic device according to the present invention, and FIGS. 2 (a) and 2 (b) are schematic front views of main parts of a conventional electromagnetic device. It is a figure and the principal part enlarged view. 1 ... Electromagnetic steel sheet, 2 ... Resin mixed with magnetic particles.

Claims (2)

(57) [Claims] 1. An electromagnetic device in which a synthetic resin containing magnetic particles is impregnated and fixed to at least an end face of a portion of an electromagnetic iron core on which electromagnetic steel sheets are laminated, where an electromagnetic coil is not wound. 2. An end face of at least a portion of an electromagnetic iron core on which an electromagnetic steel sheet is laminated, on which an electromagnetic coil is not wound, is coated and impregnated with a synthetic resin mixed with magnetic particles, and cured in a magnetic field. Manufacturing method of electromagnetic equipment.