JPS5868916A - U-shaped iron core and manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce magnetic reluctance and exciting current in a U-shaped iron core having a core leg split into two and a magnetic fluid filled in the gap defined by the split two parts of the leg, by previously cutting the split surfaces into a sawtooth shape to form slight steps. CONSTITUTION:A deformed iron core leg 10 heat-treated to deform an annular laminated core into a rectangular shape is cut into a sawtooth shape and split into two to form two U-shaped cores 11, 11'. The U-shaped cores 11 and 11' are placed with the respective cut parts 1', 2' opposite to each other, and the gap defined by the cut parts 1' and 2' is filled with a magnetic fluid obtained by mixing magnetic particles having a diameter of 3 microns and an adhesive liquid having heat resistance and insulation quality at the ratio of 1:1. Moreover, films 3, 3', 4, 4' are inserted into proper parts in the magnetic fluid filling area. Thereafter, windings 5 and 5' are wound, and the cut parts are butted against and secured to each other through the magnetic fluid and the films. Thus, the area of contact between the two split surfaces is increased, so that the magnetic reluctance decreases to permit the reduction of the exciting current.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves cutting the core leg of a deformed wound core into a sawtooth shape, dividing the core leg into two parts, and applying a magnetic liquid containing magnetic fine particles and an adhesive liquid to the cut part of the two divided parts. Regarding the filled U-shaped core fζ. More specifically, in the present invention, after the annular stratified core or the annular staggered core is heat-treated to transform it into a rectangular shape, the core legs of the deformed wound core are cut into sawtooth shapes, divided into two parts, and the cut portions are formed with regular right angles. The cutting part formed by the fine steps that are integrated on the front and back has magnetic fine particles with low eddy current loss, high chemical purity, and low deterioration over time, and has heat resistance and insulation properties. A magnetic liquid obtained by mixing with an adhesive liquid is filled, a heat-resistant and insulating film is inserted into the appropriate place on the filling surface, and the required winding is wound. The present invention relates to a U-shaped core capable of fixing a cutting part.

In the U-shaped core, which is a conventional wound core divided into two parts.

Since this method of bump joining the two-part surface requires a magnetomotive force equivalent to that of this surface, the two-part surface is inclined in the winding direction of the steel strip to increase the contact area of this surface. A simmerville form may be used. however,
With the shimmar pill type two-divided surface, there is a limit to the increase in contact area, and there is also a drawback in that the method of assembling after the division is difficult, resulting in an increase in excitation current and iron loss.

In order to improve these drawbacks, the U-shaped core of the present invention has a plurality of fine steps formed by cutting the core legs into a sawtooth shape, thereby increasing the surface area of the fine steps to improve magnetic resistance and excitation. The purpose is to reduce rush current. to this end.

By reducing the surface area of the cutting part or by decreasing the number of micro-stages to increase the surface area per micro-stage, in either case, the increase rate of the surface area over the entire surface of the cutting part is constant, and the surface area of the cutting part is increased. Improve the degree of contact between both sides.

Furthermore, there is little eddy current loss between the sides of the cutting part, and the chemical purity is high.
In addition, a magnetic liquid (hereinafter referred to as magnetic liquid) obtained by mixing magnetic fine particles with low aging deterioration and a heat-resistant and insulating adhesive liquid in a ratio of 1=1 is filled, and a heat-resistant adhesive is applied to an appropriate place on the filling surface. A film with magnetic and insulating properties (hereinafter referred to as the film) is inserted and the required winding is wound, and the cut part is fixed in a good condition with minimum thickness contact through the magnetic liquid and the film. hand.

The magnetic properties of the magnetic liquid reduce the excitation current.

Therefore, the features of the U-shaped core of the present invention are that the core legs of the 9-wound core are cut into sawtooth shapes, and a fine step is formed in the cut portion divided into two parts, and magnetic fine particles and adhesive liquid are applied to the cut portion with the fine step. Fill with the magnetic liquid obtained by mixing.

The purpose is to reduce magnetic resistance and excitation current.

Embodiments of the U-shaped core of the present invention will be described based on illustrated examples.

41 (A) and 41 (B) respectively show core legs 10 of a deformed wound core in which an annular stratified core is heat-treated to transform it into a rectangular shape.
FIG. 2 is a plan view and a front view showing the structure of two U-shaped cores 11 and 11' which are cut into two parts by sawtooth cutting. In the figure, 11 pieces of the U-shaped core are cut into 9 pieces, for example, a magnetic liquid (hereinafter referred to as "magnetic liquid") having a magnetic permeability of 2.69%, which is obtained by mixing magnetic fine particles with a diameter of 3 microns and the above-mentioned adhesive liquid at a ratio of 1:1. ,
2.69 Fix the cutting part with magnetic forceps.

Next, FIGS. 2(A) and 2(B) respectively.

The core legs 20 of the three deformed wound cores, each of which has been heat-treated to transform the annular staggered wound core into a rectangular shape, are cut into sawtooth shapes 22, 22.
23 and 23'; FIG. In the figure, a cut portion 31 of a three-phase U-shaped core 21 is shown.
and 33, respectively, are opposed to the cut parts 31 and 32' of the three-phase U-shaped core 21', and the cut parts 33 and 34 of the three-phase U-shaped core 22 are respectively opposed to the cut parts 31 and 32' of the three-phase U-shaped core 21'. Opposed to the cutting parts 33' and 34'.

The cutting parts 35 and 36 of the three-phase U-shaped core 23 are
Each has a 3-phase U-shaped core 23'? Cutting parts 35' and 3
Opposite 6'. Within this opposing gap.

For example, fill with the above 2.69 magnetic liquid, and then fill.

Coating 37.37', 38. 38',
39.39'.

40, 40', 41.41', 42 or 42'
After inserting the common leg windings 13, 13' and 1
3" was wound, and the cut portion was abutted and fixed through the 2.69 magnetic solution and the coating.

Next, a method for forming serrated cut portions on the core legs of the modified wound core will be explained using the schematic ridge view shown in FIG. 3 and the enlarged view of the cut portion shown in FIG. 4. In the figure, serrations 53 and 53 protrude in a sawtooth shape with alternating left and right inclinations for cutting.
For example, the serrated steel strip 51 has nine serrated steel strips 51 with a central tooth 52 located between them.

Core leg 10 or 2 shown in FIG. 1 or 2
Pressure is applied from the direction shown by the arrow with respect to 0, and the saw. toothed steel strip 5
1 performs oscillating\circulating motion, cutting parts 1.1', 2
．． and 2' or 33.33', 34 and h34
′ etc. These cutting portions are relative to the center line of the serrated steel strip 51, as shown in FIG.

For example, regular right-angled steps 62 are constructed with inclination angles of 80.4° and 9.6°. The serrated steel strips 51 form a set of front and back surfaces and have, for example, 195 serrations, and if the cutting thickness corresponding to one circumference of the serrated steel strip 51 is, for example, 0.68 E. , the cutting thickness to be cut by the unit sawtooth is ('0.68+19
5=) 0.0035 mm.

Furthermore, when configuring the serrated steel strip 51 in a loop shape and doubling the speed of its circulating motion, the surface area of the cutting portion will be doubled, so even if the number of fine steps 62 is halved, it will not be the same as before. The same surface area can be maintained. In other words, the surface of the cutting part, the furnace, is obtained by multiplying the surface area of the micro-stage by the number of micro-stages, so as the individual surface area of the micro-stage increases, the number of stages decreases, and the number of stages increases. .

Furthermore, it is also possible to provide fine steps 63 and 63', which have the same inclination angle as the fine step 62 and divide it into two, in place of the fine step 62 by controlling the swinging of the serrated steel strip 51. At this time, the number of stages such as the fine stage 63 is twice the number of stages such as 62, the swinging speed is halved, and the surface area of the cutting part is maintained the same in both.

The cut portion of the U-shaped core provided as described above is filled with a magnetic liquid so as to satisfy, for example, the following requirements.

As shown in the enlarged view of the cutting part in FIG. Cutting parts 1 and 1' are fixed to each other via coatings 3 and 3'.

The composition relationship of the magnetic liquid 60 obtained by mixing magnetic fine particles and adhesive liquid at a ratio of 1:1 is illustrated in FIG. In Figure 2, if the diameter 2R of the magnetic fine particles is, for example, 3 microns, and the distance between the centers of the magnetic fine particles is aE cron, then the following equation can be obtained approximately from the mixing ratio of 1:1. .

4+rR/3='a3-. 4πR/ 3 -- (1
) By substituting 2R=3 microns into equation (1), a
=3°046 microns is obtained. That is, the gap t between the magnetic particles is t=3
．． 046-3=0°046 microns.

Therefore, the compounding ratio Q of magnetic fine particles and adhesive liquid is Q=3÷
It is given as 3°046=0.9848.

Furthermore, the gap between the fine steps 62, etc. of the cutting parts 1 and 1' is 0.2
5 mm, and the maximum Trn in this case is Tm
, -0,25x Q = 0.246 millimeters.

Number of magnetic fine particles distributed in series in the gap N = 0゜2
46 millimeters + 3 microns - 82 pieces, and the thickness Tn of the adhesive in series with the magnetic fine particles.

It is given as Tn=0°25÷at=0.00378 mm.

Also, assuming that the dielectric breakdown strength corresponding to the dielectric breakdown voltage in this case is 40 kilovolts/mm.

The dielectric breakdown voltage VB per adhesive liquid thickness T□ is ■B=40
Kip Holt x T□ = 151°2 Holt, and the same voltage VBO that can be continuously applied is, for example, VB, = V, x 15% = 22.65 volts, and the insulation resistance value over the entire adhesive liquid is 10 You can get more than kilograms.

The magnetic liquid composed of the above-mentioned magnetic fine particles and adhesive liquid maintains appropriate magnetic resistance and adhesive force, and the excitation current is reduced by the magnetic properties of the magnetic liquid without directly contacting the cutting part. In this case, the excitation current ■. (Ampere) is expressed by the following formula.

■o=to, Bm×1/i1NIX(ff/μs +21
ty'μF8)・・・・・・(2) In equation (2), 1: Proportionality constant BIn= Magnetic flux density (Gauss) N: Number of primary turns (turns) ■: Primary current (ampere) l: Magnetic path Length (cm) 4g: Thickness of adhesive liquid (cm) μS:
Iron core magnetic permeability μF8: This is the magnetic permeability of the magnetic liquid. Also, in general, the maximum value of excitation rush current ■,! 1aX(
ampere) is expressed by the following formula.

T,, aX=n(2ψ. 1ψ, −2Ak2.) /
L=r1A (2 Bo + Br-2)/L...
(3) In formula (3), n - 2 Number of excitation windings (turns), ψrn: Magnetic flux (Weber) = ABI, lA: Core cross-sectional area (square centimeters) Brn: Magnetic flux density (Gauss) ψr = Residual magnetic flux (Weber) =AB'B,: Residual magnetic flux density (Gauss) k2: Proportionality constant L: Air core impedance of excitation winding (Henry) =
0゜4πAn"/h' -11: Height of excitation winding (cm) When comparing Imax with the maximum value of excitation rush IuI!lax in the U-shaped core of the present invention,
As a result of experiments, it has been found that the maximum values Iu and nax are significantly reduced compared to the maximum value ■max. In addition, according to the present invention (?), when the cutting part is filled with a magnetic liquid mixed in an appropriate ratio, the excitation current decreases due to the magnetic properties of the magnetic liquid.
In addition, it has been confirmed from the actual results that the electrical properties of the magnetic liquid suppress interlayer short circuits and prevent dielectric breakdown at the cut portion. Although the reason for this has not been fully elucidated, it is thought to be due to the following causes.

The total surface area of the cut portion of the U-shaped core of the present invention is the surface area of a unit fine step multiplied by the number of fine steps, and the surface area and 9
．． In the 6° example, the calculation using trigonometric functions yields Sin 80.4° = 0.986 and Sin 9.
6°−〇. By obtaining 167, 0.986 + 0.167 = 1.
It becomes 153 times. In addition, in Equation 9 (3), to the magnetic flux 2 +
ψ1-2Al (2 is thought to pass through the air gap inside the excitation winding, and the saturation magnetic flux density in this case is 2Ak2, but in the cut portion of the U-shaped core of the present invention!).

The saturation magnetic flux density is 2A'2 = 2 x 1.153Ak2 = 2.3
06Ak2, and it is theorized that the excitation rush current is reduced by this.゛Figure 6 shows an example of an excitation characteristic curve when the U-shaped core of the present invention is applied to a three-phase, 50 kilovolt ampere, 60 hertz, 200 volt transformer. The axis represents the excitation current. In this example, when the content of magnetic fine particles is increased.

It turns out that the excitation characteristic curve tends to rise more orthogonally and that the excitation current required to produce the required magnetic flux density decreases.

Figures 7 and 8 both show the compounding relationship between magnetic fine particles and adhesive liquid. The vertical axis in Figure 7 represents the applied voltage, the horizontal axis represents the excitation current, and the vertical axis in Figure 8 represents the applied voltage. The magnetic permeability of the magnetic liquid is
The horizontal axis represents the content of magnetic fine particles. Both figures show that as the content of magnetic fine particles increases, the excitation current decreases, and thus the magnetic permeability of the magnetic liquid increases.

゛When a single-phase or three-phase U-shaped iron R6 type transformer using the U-shaped core of the present invention is connected to a thyristor circuit or the secondary i of an inverter, its excitation characteristics are even better and technical In addition, an economically superior U-shaped core can be obtained. ``9 Therefore, in the U-shaped core of the present invention, the excitation current is reduced due to the magnetic properties of the magnetic liquid, and the electrical properties of the magnetic liquid suppress interlayer short circuits and prevent dielectric breakdown at the cut portion. This was achieved by combining many years of technical experience with original creativity, and resulted in an economically superior U-shaped core.

[Brief explanation of drawings]

Figure 1 and (13) each represent 9 U of the present invention.
FIG. 2 is a plan view and a front view showing the structure of a shaped iron core. FIG. 2(A) and FIG. 2(B) respectively show 9 three-phase U of the present invention.
FIG. 2 is a plan view and a front view showing the structure of a shaped iron core. FIG. 3 and FIG. 4 are a schematic view and an enlarged view, respectively, illustrating a method of forming sawtooth-like cutting portions in a V-shaped core according to the present invention. FIG. 5 is an enlarged explanatory view showing the magnetic liquid filled in the cutting part shown in FIG. 4. FIG. FIG. 6 shows an example of an excitation characteristic curve to which the U-shaped core of the present invention is applied. FIGS. 7 and 8 are characteristic curves showing the blending relationship between magnetic fine particles and adhesive liquid. 9 is a schematic diagram showing the positional relationship between the magnetic fine particles and the adhesive liquid. 1, 1', 2.2', 31.31', 32.32
', 33.33'. 34, 34', 35.35', 36.36'...
・Cutting part. 3, 3', 4.4', 37.37', 38.38
', 39.39', 40.41'. 42, 42'... Coating, No. 5, 5', 13.13', 13"... Winding wire. 10, 20... Iron core leg. 11, 11', 21.21', 22., 22',
23.23'...U-shaped iron core. 51... Serrated steel strip. 53.53'...Sawtooth. 60...Magnetic liquid. 62,, 63, 63'...Minor patent issuer: Tokuden Co., Ltd. Agent: Patent attorney (6695) Keiji Kato LIJ)
Tail 2 figure (8) Tail 3 figure Ke 4 figure Hou 5 Oot figure Issuke Nagi Shinryu 4 Ke 7 figure Tail 8 [2] -p/Jm electric;
One layer a-sexual I (including string 3) i "(ni) hair map

Claims (1)

[Scope of Claims] (1) A U-shaped core characterized in that a core leg of a modified wound core is cut into two parts, and a sawtooth-like step is formed in the cut part. (2. A U-shaped iron core according to claim 1, characterized in that a magnetic liquid containing a mixture of magnetic fine particles and an adhesive liquid is filled between the fine steps of the cut portion. (3) The U-shaped iron core according to claim 2, wherein the monomagnetic liquid is obtained by mixing the magnetic fine particles and the adhesive liquid at a mixing ratio of 1:1. Characteristic U-shaped core. (4) The core legs of the deformed wound core are made by the oscillating circulation movement of a serrated copper band having serrated teeth that protrude at an angle alternately on the left and right sides and a central tooth located in the middle. A method for manufacturing a U-shaped core, the method comprising: cutting to form sawtooth-like fine steps in the cut portion. (5) A method for manufacturing a U-shaped core according to claim 4, comprising: , manufacturing a U-shaped iron core characterized in that the speed of the oscillating circulation movement of the serrated copper strip is changed and the total area of the fine steps formed in the cutting part is maintained at a constant value. Method.