JP4473476B2 - Manufacturing method of core for low noise winding transformer - Google Patents

Description

【００１６】
［実施例２］
通常の方法で製造された板厚０．２７mmの一方向性電磁鋼板によって巻き鉄心を作り、２０kVA 三相鉄心形トランスを作製した。Ｅはラップ接合で樹脂層として厚さが４０μｍのポリエステルを用いた複層電磁鋼板を通常の電磁鋼板に挟んで積層した。樹脂層はその厚さがトランスの全層厚に対して５％となるように等間隔に挿入した。Ｅは従来の製造法と同様に鉄心に成形後、焼鈍し、鉄心をばらして巻き線を挿入してコアにした。この場合、焼鈍により樹脂層が変質して振動吸収能力が消失し、騒音は高くなった。
【００１７】
本発明の条件を満たす方法で製造したトランスＦにおいてもＥと同様な樹脂を用いた複層電磁鋼板を通常の電磁鋼板に挟んで、同様な接合法で積層した。樹脂層はその厚さがトランスの全層厚に対して５％となるように等間隔に挿入した。樹脂層がある複層電磁鋼板は焼鈍せず、樹脂層のない電磁鋼板を焼鈍し、バラシ作業後、これらを組み合わせた。これらのトランスを６０Hz １．７Ｔで励磁したときの騒音を表２に示す。本発明例のＦでは樹脂層が変質せず、騒音を約５dB低くすることが出来た。
【００１８】
【表２】

【００１９】
【発明の効果】
以上説明したように、本発明によれば鋼板面に垂直な振動を抑える樹脂中間層が最終歪み取り焼鈍で変質することを防ぎ、低騒音化を効果的に実現する、優れた低騒音巻きトランス製造法が容易に提供でき、電機機器の低騒音化が図られ、産業上の利益は極めて大きい。
【図面の簡単な説明】
【図１】巻きトランス鉄心の製造工程を示したものである。
【図２】本発明技術である工程を示したものである。[0001]
[Field of the Invention]
The present invention relates to a core for a wound transformer and a method for manufacturing the same, and more particularly to a method for manufacturing a core for a low-noise wound transformer that generates less vibration.
[0002]
[Prior art]
In magnetic materials widely used in electrical and electronic equipment, the degree of change in length when a magnetic field is applied (called magnetostriction) causes transformer noise, and is therefore an important evaluation item in quality control. It has become. In recent years, noise from electric appliances is becoming more restrictive along with a demand for comfortable living environment. For this reason, research on noise reduction by reducing magnetostriction has been actively conducted.
[0003]
With regard to the unidirectional electrical steel sheet used for the iron core of the transformer, great progress has been made and there is a technique for reducing magnetostriction by reducing the reflux magnetic domain. The reflux magnetic domain referred to here is a region having magnetization that is oriented at right angles to the magnetic field application direction. Magnetostriction occurs when this magnetization moves in the direction parallel to the magnetic field by the applied magnetic field. Therefore, the smaller the reflux magnetic domain amount, the smaller the magnetostriction. The following are known as main methods for reducing magnetostriction.
(1) A method in which the <001> direction of the crystal grains is aligned with the rolling direction and a reflux magnetic domain that causes a shape change by magnetization rotation is not created (T. Nozawa et al, “Relationship Between Total Losses under Tensile Stress in 3 Percent Si- (Fe Single Crystals and Their Orientations near (110) [001] ”, IEEE Trans. On Mag., Vol. MAG-14, No. 4, 1978.)
(2) A method of erasing the reflux magnetic domain by releasing plastic strain (Japanese Patent Laid-Open No. 7-305115, [Development of a directional silicon steel orient core / hibey: OHM1972.2),
(3) A method of erasing the reflux domain by applying film tension to the steel sheet (T. Nozawa et al, “Relationship Between Total Losses under Tensile Stress in 3 Percent Si-Fe Single Crystals and Their Orientations near (110) [001] ] ”, IEEE Trans. On Mag., Vol. MAG-14, No.4, 1978.)
[0004]
On the other hand, not only the reduction of the magnetostriction of the steel sheet, that is, the core sheet, but also the method of suppressing the vibration generated by the core is aimed at reducing the noise. As a method of reducing noise by suppressing the vibration generated by the core, for example, a method of providing an air space or silicone rubber to cut off the propagation of vibration (Japanese Patent Laid-Open No. 5-251246), a damping material and a sound absorbing material are attached to the core leg. A method of reducing noise by placing it outside (JP-A-8-45751, JP-A-2000-82622, JP-A-2000-124044), and a method of fixing the gap portion of the reactor with an adhesive that can suppress vibration (JP-A-8-85). 111322), and a method using a magnetic steel sheet having a resin intermediate layer (Japanese Patent Laid-Open No. 8-250339).
Mainly by these methods, the magnetostriction of the core sheet or the vibration of the core has been reduced to reduce the noise of the electrical equipment.
[0005]
[Problems to be solved by the invention]
There is a strong demand for further noise reduction of electrical equipment, and more advanced technology is required to achieve the purpose. The conventional research on noise reduction has been mainly aimed at reducing the magnetostriction of the core sheet by the disappearance of the reflux magnetic domain. However, when a time-varying magnetic field is applied, when the transformer core is assembled, the expansion and contraction of the core sheet changes to vibration perpendicular to the core sheet surface because the core sheet is not necessarily flat. This vibration creates a dense wave of air and spreads as sound. Until now, in order to reduce this vibration, the above-mentioned sharpening of crystal orientation, release of plastic strain, application of tension, etc. have been established so as to reduce the magnetostriction of the core sheet. In addition, there is a measure to provide an anti-vibration structure that does not propagate vibration to the outside. However, in order to cope with the demand for further noise reduction, it is a problem to suppress the surface vibration of the core sheet that causes air particle vibration.
[0006]
For such a problem, a core composed of a multilayered electrical steel sheet having a resin intermediate layer has already been proposed in a stacking transformer. However, in a winding transformer, it is necessary to anneal the core at 800 ° C. in the final process for distortion removal. In this case, the resin intermediate layer is altered, and the target iron core cannot be manufactured.
[0007]
The object of the present invention is to have a resin intermediate layer that suppresses vibration perpendicular to the core sheet surface, find conditions for avoiding alteration of the resin intermediate layer after final strain relief annealing, and effectively realize low noise generation. It is to provide a manufacturing method of a core for a low noise winding transformer with a small amount of noise.
[0008]
[Means for Solving the Problems]
Specific means of the present invention are as follows.
(1) Using a normal electromagnetic steel sheet as a core sheet, forming into a core and annealing step A,
Step B, in which a multilayer electromagnetic steel sheet having a resin intermediate layer having a thickness of 10 to 100 μm between two magnetic steel sheets laminated as a part of the core sheet is formed into a core and is not subjected to strain relief annealing , and
After separating the core of the step A, the core sheet formed in step B is mixed to form a core, and the step C includes inserting a winding.
Low noise winding method for manufacturing a transformer core, wherein the weight ratio of the core sheet of the step B to the core sheet of the A step is 3-10.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
As already mentioned, the main method of noise reduction up to now has been to reduce the magnetostriction of the core sheet and reduce the surface vibration. Moreover, the vibration-proof structure which did not propagate the vibration of a core outside was taken. However, in the method of inserting a viscoelastic body layer having both viscosity and elasticity between core sheet laminations in the core of the transformer, the present inventors have adopted a technique for reducing the surface vibration of the core sheet and reducing noise in the winding transformer. In order to realize it effectively, we conducted intensive research. This will be described below based on experiments.
[0010]
FIG. 1 shows a general manufacturing process of a core of a winding transformer. First, the coil is slit to a required width, a core sheet sheared to a predetermined length is wound, and pressed from four sides using a jig to form a rectangular sheet. At this time, an iron mold is sandwiched so that the inside diameter is not crushed and molding is performed. Next, the molded core is subjected to strain relief annealing at 800 ° C., the core is separated to insert the winding wire into the iron core, and the core is opened in a U shape. After inserting the winding, combine the core sheets again. In this step, the resin between the core sheets is altered during the core distortion removal annealing, and the vibration absorption effect cannot be enjoyed.
[0011]
In order to solve the above problems, a process that satisfies both the advantages of strain relief by annealing and the prevention of alteration of the resin intermediate layer was investigated. FIG. 2 shows a process according to the present invention. In step A, a normal electromagnetic steel sheet is used as the core sheet, which is formed into a core and annealed. In step B, a multilayer electromagnetic steel sheet having a resin intermediate layer is used as a core sheet, and the core sheet is molded into a core and not annealed. In the present invention, after the core of Step A is released, the core sheet formed in Step B is mixed to form a core, and the winding is inserted (Step C). Here, by setting the weight ratio of the core sheet of the process A and the process B to about 3 to 10, the core vibration can be absorbed, that is, the transformer noise can be reduced while preventing a large increase in iron loss due to distortion.
[0012]
Next, the reasons for limiting the present invention will be described.
First, if the thickness of the resin layer between the laminations of the electrical steel sheets forming the core is less than 10 μm, the vibration absorption capacity becomes insufficient, and if it exceeds 100 μm, the number of non-magnetic layers increases, so the magnetic flux density in the electrical steel sheet increases. And, since the effect of low noise cannot be obtained, it is limited to 10 to 100 μm. Moreover, the reason why a plurality of resin layers are provided in the core is that the effect of low noise was not observed in the case of only one location in the experiment.
The reason why the resin layer is provided at a plurality of locations until the thickness becomes 1% or more of the core thickness is that noise reduction does not appear remarkably at a resin layer thickness less than this.
Furthermore, the reason why the multilayer electromagnetic steel sheet having the resin layer is used without being subjected to strain relief annealing is to avoid the loss of the vibration absorbing ability due to the alteration of the resin layer at a high temperature. As the resin, polyisobutylene, polyester, nitrile rubber, or the like is used. However, any resin having vibration absorption ability may be used, and these types are not specified. In the following, description will be given based on examples.
[0013]
【Example】
[Example 1]
A wound iron core was made from a unidirectional electrical steel sheet with a thickness of 0.23 mm manufactured by a conventional method, and a 16 kVA three-phase core transformer was produced. A is a lap joint and nitrile rubber is used as a resin layer, D is a butt joint and polyester is used as a resin layer. The thickness of the resin layer used here is 50 μm. The resin layers were inserted at equal intervals so that the thickness was 5% with respect to the total thickness of the transformer. A and D were formed into an iron core in the same manner as in the conventional manufacturing method, and then annealed, and the core was separated and a winding was inserted into a core. In this case, the resin layer was altered by annealing, the vibration absorbing ability was lost, and the noise increased.
[0014]
In the transformer manufactured by the method satisfying the conditions of the present invention, B is a lap joint and a nitrile rubber is used as a resin layer, and C is a butt joint and a multilayer electrical steel sheet using polyester as a resin layer is sandwiched between ordinary electrical steel sheets. . The resin layers were inserted at equal intervals so that the thickness was 5% with respect to the total thickness of the transformer. The multilayer electrical steel sheet with the resin layer was not annealed, the electrical steel sheet without the resin layer was annealed, and these were combined after the brushing operation. Table 1 shows the results of excitation of these transformers at 50 Hz 1.65 T and measurement of noise. B and C existed without deterioration of the resin layer, and the noise was about 5 dB lower than that of the comparative example.
[0015]
[Table 1]

[0016]
[Example 2]
A wound iron core was made from a unidirectional electrical steel sheet with a thickness of 0.27 mm manufactured by a normal method to produce a 20 kVA three-phase iron core transformer. E was laminated by sandwiching a multilayered electrical steel sheet using polyester having a thickness of 40 μm as a resin layer by lap joining with a normal electrical steel sheet. The resin layers were inserted at equal intervals so that the thickness was 5% with respect to the total thickness of the transformer. In the same manner as in the conventional manufacturing method, E was formed into an iron core and then annealed, and the core was released to insert a winding into a core. In this case, the resin layer was altered by annealing, the vibration absorbing ability was lost, and the noise increased.
[0017]
In the transformer F manufactured by the method satisfying the conditions of the present invention, a multilayer electromagnetic steel sheet using the same resin as E was sandwiched between ordinary electromagnetic steel sheets and laminated by the same joining method. The resin layers were inserted at equal intervals so that the thickness was 5% with respect to the total thickness of the transformer. The multilayer electrical steel sheet with the resin layer was not annealed, the electrical steel sheet without the resin layer was annealed, and these were combined after the brushing operation. Table 2 shows the noise when these transformers are excited at 60 Hz 1.7 T. In F of the present invention example, the resin layer did not change and the noise could be reduced by about 5 dB.
[0018]
[Table 2]

[0019]
【The invention's effect】
As described above, according to the present invention, the resin intermediate layer that suppresses vibration perpendicular to the steel plate surface is prevented from being deteriorated by final strain relief annealing, and an excellent low noise winding transformer that effectively realizes low noise. The manufacturing method can be provided easily, the noise of the electrical equipment can be reduced, and the industrial profit is extremely large.
[Brief description of the drawings]
FIG. 1 shows a manufacturing process of a wound transformer core.
FIG. 2 shows a process which is a technique of the present invention.

Claims (1)

Using a normal electromagnetic steel sheet as a core sheet, forming into a core and annealing step A,
Step B, in which a multilayer electromagnetic steel sheet having a resin intermediate layer having a thickness of 10 to 100 μm between two magnetic steel sheets laminated as a part of the core sheet is formed into a core and is not subjected to strain relief annealing , and
After separating the core of the step A, the core sheet formed in step B is mixed to form a core, and the step C includes inserting a winding.
Low noise winding method for manufacturing a transformer core, wherein the weight ratio of the core sheet of the step B to the core sheet of the A step is 3-10.

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