JPH08250338A - Transformr iron core - Google Patents

Abstract

PURPOSE: To obtain a transformer iron core which is lessened in no-load loss and noise and improved in magnetic characteristics by a method wherein magnetic steel plates are laminated so as to set a T joint between an iron core middle leg and a yoke both formed of magnetic steel plates smaller in step width than a corner joint between an iron outer leg and the yoke. CONSTITUTION: A core middle leg 1 is formed through such a manner that hexagonal magnetic steel plates 11 each possessed of right-angled tips at both its lengthwise ends are laminated making the magnetic steel plates 11 of the core middle leg 1 at a T joint 4 between the core middle leg 1 and a yoke 3 deviate from the magnetic steel plates 13 of the yoke 3 in step width B13 . A core outer leg 2 is formed through such a manner that trapezoidal magnetic steel plates 12 each possessed of a 45 deg.-angled tip which confronts the core middle leg 1 inward are laminated making the magnetic steel plates 12 of the core outer leg 2 at a joint corner 5 between the iron outer leg 2 and the yoke 3 deviate from the magnetic steel plates 13 of the yoke 3 in step width B23 . At this point, the step width B13 is set smaller than the step width B23 .

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a transformer core, and more particularly to a step wrap core.

[0002]

2. Description of the Related Art Generally, grain oriented silicon steel plates are used in transformer cores, and the joint ends of the silicon steel plates are cut at 45 ° so that magnetic flux can pass in the rolling direction even at the joint between the core leg and yoke. With a frame shape, the magnetic steel plate of the leg and the magnetic steel plate of the yoke part are partially overlapped to make a lap joint method to prevent vibration and noise due to the magnetic attraction force acting on the joint surface. .

Further, in recent years, as seen in Japanese Utility Model Publication No. 57-170527 and Japanese Patent Publication No. 60-30089, the outer legs of the iron core on both the left and right sides of the three-leg iron core are joined to the upper and lower yoke portions. Trapezoids cut at 45 ° on opposite sides of each other,
The iron core middle leg is hexagonal with both ends V-shaped, and the upper and lower yoke parts have 45 ° where both ends join the joint ends of the left and right iron core outer legs. A V-shaped notch with a size corresponding to the shape is provided, and these iron core legs and yokes are formed by stacking a large number of magnetic steel sheets, and the end faces of the magnetic steel sheets at the joints are stepwise arranged in the same direction. This is a so-called step-like stacked iron core formed by stacking the two in a stepwise manner, and these are joined and assembled to reduce iron loss.

[0004]

When the step wrap iron core is assembled, as shown in FIG. 7, the triangular portion where the magnetic steel plates are not joined to the inner corner of the iron core window as shown in FIG. (Provisionally referred to as a notch) a ₁ and a ₂ occur.

That is, FIG. 7 is an enlarged view for explaining a joint portion between the yoke portion 3 and the iron core outer leg 2 of the three-phase three-leg iron core, and the iron core outer leg 2 has two magnetic steel plates with a width of Center the same 12-
1, 12-2 and the step width B23 are formed so as to be shifted upward, and the yoke portion 3 has the same width center in the same manner as the outer core of the iron core according to the step width B23.
-1, 13-2 and the left side of the figure are formed so as to be shifted so that the end faces of the magnetic steel plates 12-1 and 13-1 and 12-2 and 13-2 are joined to each other.

As described above, the magnetic steel plates 12 are joined together.
At the joint between -1 and 13-1 and the joint between 12-2 and 13-2, the triangular portion a ₁ , which is not joined at the inner corner,
a ₂ will occur.

In the transformer core, the magnetic flux Φ passes through the corner portion, which is a joint portion between the core leg (outer leg) and the yoke, so as to approach the window side of the core having a small magnetic resistance. As shown in the drawing, when the step width of the magnetic steel plate is large, the notch is large, the magnetic flux Φ bulges toward the outer side of the iron core, the magnetic resistance is large, and the loss, iron loss, vibration noise, etc. are large. Figure 7
As shown in (B), when the step width of the magnetic steel sheet is small and the notch is small, the magnetic flux has a small bulge toward the outer side of the iron core, and the magnetic resistance is small as compared with FIG. 7 (A).
Loss, iron loss, vibration noise, etc. are also small.

When the step width is increased or the number of steps is increased in the step lap joining of magnetic steel plates, the notch becomes large and the magnetic flux distribution is disturbed, which causes deterioration of the iron core characteristics such as loss. . In particular, at the T-joint, which is the joint between the iron core middle leg and the yoke, the deviation of the magnetic flux at the corner was in one direction inside the window, whereas the deviation of the magnetic flux was not in one direction but in both directions. Occurs in Therefore, when treated in the same manner as the corner portion, there is a problem that the larger the notch, the more the loss increases.

The present invention has been made in view of the above problems of the prior art, and has a small no-load loss,
An object of the present invention is to provide a transformer with good magnetic properties and low noise.

[0010]

In order to achieve the above-mentioned object, a transformer core according to the present invention has a step width of a magnetic steel sheet at a T-joint which is a joint between an intermediate leg of an iron core and a yoke portion. By making the size of the notch of the V-shaped joint smaller than the size of the notch of the corner by making it smaller than the step width of the magnetic steel plate of the corner that is the joint of the outer leg and the yoke, By stacking the layers, the disturbance of the magnetic flux at the T junction is reduced, the magnetic resistance is reduced, the excitation characteristic is improved, and the no-load loss is reduced.

Also, the T which is the joint between the core core leg and the yoke part
The step width of the magnetic steel plate at the joint is made smaller than the step width of the magnetic steel plate at the corner, which is the joint between the outer core leg and the yoke, and the number of steps of the magnetic steel plate at the T joint is set to By laminating more than the number of steps of the steel sheets to reduce the disturbance of the magnetic flux at the T-junction, the magnetic resistance is reduced, the excitation characteristic is improved, and the no-load loss is reduced.

Further, the step width of the magnetic steel sheet at the corner portion which is the joint portion between the outer core leg and the yoke portion is larger than the step width of the magnetic steel sheet at the T joint portion which is the joint portion between the core inner leg and the yoke portion. At the same time, the number of steps of each magnetic steel plate is set to the same number, and the magnetic steel plates at the corners are laminated by changing the length by a plurality of sheets, thereby reducing the disturbance of the magnetic flux at the T-junction and reducing the magnetic resistance. It improves excitation characteristics and reduces no-load loss.

[0013]

With the above-described structure, the step width of the magnetic steel sheet at the T joint, which is the joint between the core core leg and the yoke portion, is determined by the magnetic field at the corner, which is the joint between the core outer leg and the yoke portion. By stacking these magnetic steel sheets with a width smaller than the step width of the steel sheets, the size of the cutout at the T-joint is made smaller than the size of the cutout at the corner.
Disturbance of magnetic flux at the joint is reduced to reduce loss.

Further, by increasing the number of steps of the above-mentioned steel plates at the T-joint to smooth the flux passage within one block (blocks in the stacking direction for each number of steps), loss, excitation characteristics, Improves noise characteristics.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view schematically showing a three-phase three-leg iron core having upper and lower yoke portions, an iron core outer leg and an iron core middle leg of an embodiment of a transformer iron core of the present invention. On both sides of the iron core middle leg 1 in which hexagonal magnetic steel plates 11 having 90 ° angle (V-shaped) tips at both ends in the length direction are laminated,
45 ° from the tip toward the inside facing the iron core middle leg 1
And an iron core outer leg 2 on both ends of which an iron core outer leg 2 having a trapezoidal magnetic steel plate 12 having a tip end at an angle of 2 is arranged.
Has a V-shaped notch with an angle of 90 ° to be joined to the 90 ° angled end of the iron core middle leg at the center of the trapezoid having an angled 45 ° from the tip facing inward. The yoke portion 3 formed by laminating magnetic steel plates 13 joins the upper or lower portions of the iron core legs to form a magnetic path to form a three-phase three-leg iron core.

The magnetic steel plate 11 of the iron core middle leg 1 and the magnetic steel plate of the yoke portion 3 have a predetermined step width B at the T-joint 4.
₁₃ (refer to FIG. 2), the magnetic steel plates 12 of the iron core outer leg 2 and the magnetic steel plate 1 of the yoke portion 3 are laminated while shifting the butting positions.
3 is a corner portion 5 and has a predetermined step width B ₂₃ (see FIG. 3)
Are stacked while shifting the butting position. In FIG. 1, the apex of the V-shaped cutout portion of the magnetic steel plate 13 is moved in the longitudinal direction of the yoke portion 3 at the T-joint, but when this apex is moved in the width direction of the yoke portion 3 and laminated. Therefore, the present invention includes any of the above cases.

FIG. 2 is a front view showing an example of a situation in which the core core legs of the transformer core of the present invention are stacked. In FIG. 2, the core core legs 1 are 90 ° at both ends in the longitudinal direction. A hexagonal magnetic steel plate 11 having an angled tip is used for a magnetic steel plate 11 of the iron core middle leg 1 and a magnetic steel plate 13 of the yoke part 3 at a T joint 4 which is a joint between the iron core middle leg 1 and the yoke part 3. And the step width B ₁₃ is shifted and laminated.

FIG. 3 is a front view showing an example of the laminated state of the outer core legs of the transformer core according to the present invention. In FIG. 3, the outer core leg 2 is an inner side facing the inner core leg 1. A trapezoidal magnetic steel plate 12 having a tip portion at an angle of 45 ° from the tip is a joint portion between the outer core leg 2 and the yoke portion 3 of FIG.
It is laminated by shifting the step width B ₂₃ of the magnetic steel plate 12 and the magnetic steel plates 13 of the yoke portion 3 of the core outside the leg 2 at the corner portions 5 of the.

FIG. 4 is a perspective view showing the laminated shape of the upper yoke portion of the first embodiment of the transformer iron core of the present invention. In FIG. 4, at the joint portion of the iron core middle leg 1 and the iron yoke portion 3. The step width B ₁₃ between the magnetic steel plate 11 of the iron core middle leg 1 and the magnetic steel plate 13 of the yoke part 3 in a certain T-joint 4 is determined by the iron core in the corner part 5 which is the joint between the iron core outer leg 2 and the yoke part 3. The step width B ₂₃ between the magnetic steel plate 12 of the outer leg 2 and the magnetic steel plate 13 of the yoke part 3 is set smaller than that of the magnetic steel plate 11 of the iron core middle leg 1, the magnetic steel plate 12 of the iron core outer leg 2, and the yoke part. The magnetic steel sheets 13 of No. 3 are laminated and formed.

FIG. 4 shows that the step width B ₁₃ of the T-junction portion 4 is ½ of the step width B ₂₃ of the corner portion 5.

In this case, the iron core middle leg 1 and the iron core outer leg 2
Are stacked in the state shown in FIGS. 2 and 3.

FIG. 5 is a perspective view showing the laminated shape of the upper yoke portion of the second embodiment of the transformer iron core of the present invention. In FIG. 5, at the joint portion between the iron core middle leg 1 and the yoke portion 3. The step width B ₁₃ between the magnetic steel plate 11 of the iron core middle leg 1 and the magnetic steel plate 13 of the yoke part 3 in a certain T-joint 4 is determined by the iron core in the corner part 5 which is the joint between the iron core outer leg 2 and the yoke part 3. The step width B ₂₃ between the magnetic steel plate 12 of the outer leg 2 and the magnetic steel plate 13 of the yoke portion 3 is made smaller, and the core middle leg 1 of the T core joint 1 at the joint portion 4 of the iron core middle leg 1 and the yoke portion 3 is The number of steps between the magnetic steel plate 11 and the magnetic steel plate 13 of the yoke portion 3 is set to be the same as that of the magnetic steel plate 12 of the iron core outer leg 2 and the yoke portion 3 of the corner portion 5 which is the joint portion of the iron core outer leg 2 and the yoke portion 3. The number of steps with the magnetic steel plate 13 is larger than the number of steps, and the magnetic steel plates 13 are stacked. In FIG. 5, the step width B ₁₃ of the T-joint 4 is the step width B ₁₃ of the corner portion 5.
_The number is 1/2 of ₂₃ , and the number of steps in the corner portion 5 is doubled. In this case, the iron core middle leg 1 and the iron core outer leg 2 are laminated in a state substantially the same as the state shown in FIGS. 2 and 3.

FIG. 6 is a perspective view showing the laminated shape of the upper yoke portion of the third embodiment of the transformer iron core of the present invention. In FIG. 6, at the joint portion between the iron core middle leg 1 and the yoke portion 3. The step width B ₁₃ between the magnetic steel plate 11 of the iron core middle leg 1 and the magnetic steel plate 13 of the yoke part 3 in a certain T-joint 4 is determined by the iron core in the corner part 5 which is the joint between the iron core outer leg 2 and the yoke part 3. The step width B ₂₃ between the magnetic steel plate 12 of the outer leg 2 and the magnetic steel plate 13 of the yoke part 3 is made smaller, and the magnetic steel plate 11 of the iron core middle leg 1 and the magnetic steel plate 13 of the yoke part 3 at the T joint 4 are used. And the number of steps of the magnetic steel plate 12 of the iron core outer leg 2 and the magnetic steel plate 13 of the yoke part 3 in the corner portion 5 which is the joint portion of the iron core outer leg 2 and the yoke portion 3 are the same. A transformer formed by laminating a plurality of magnetic steel plates 13 of the part 5 with varying lengths one by one. A heart and a method of manufacturing the same. Figure 6
Shows that the step width B ₁₃ of the T-joint portion 4 is set to 1/2 of the step width B ₂₃ of the corner portion 5 and the number of the corner portions 5 to be laminated simultaneously is two. In this case, the iron core middle leg 1 is laminated in the state of FIG. 2, and the iron core outer leg 2 is laminated in almost the same state as that shown in FIG. 3 (two sheets with the same step width).

[0025]

Since the present invention is configured as described above, the following effects can be obtained.

The step width of the magnetic steel plate at the T-joint, which is the joint between the iron core middle leg and the yoke portion, is smaller than the step width of the magnetic steel plate at the corner, which is the joint between the outer core leg and the yoke portion. Thus, by making the size of the notch of the T-joint smaller than the notch of the corner part, and laminating the magnetic steel plate of the iron core middle leg or the iron core outer leg and the magnetic steel plate of the yoke part, Since the disturbance of the magnetic flux at the T junction is reduced, the loss can be reduced.

Further, by increasing the number of steps of the magnetic steel plates at the T-joint to smooth the passage of the magnetic flux within one block (blocks in the stacking direction for each number of steps), loss, excitation characteristics, Improves noise characteristics.

[Brief description of drawings]

FIG. 1 is a front view schematically showing a three-phase three-leg iron core of an embodiment of a transformer iron core of the present invention.

FIG. 2 is a front view showing an example of a situation in which the core core legs of the transformer core of the present invention are laminated.

FIG. 3 is a front view showing an example of a situation in which the core outer legs of the transformer core of the present invention are laminated.

FIG. 4 is a perspective view showing a laminated shape of an upper yoke portion of the first embodiment of the transformer core of the present invention.

FIG. 5 is a perspective view showing a laminated shape of an upper yoke portion of the second embodiment of the transformer core of the present invention.

FIG. 6 is a perspective view showing a laminated shape of an upper yoke portion of a transformer iron core according to a third embodiment of the present invention.

FIG. 7 is a conceptual diagram for explaining a difference in magnetic flux distribution depending on a step width (or a notch) of a corner portion of a three-phase three-leg iron core.

[Explanation of symbols]

1 ... Iron core middle leg 2 ... Iron core outer leg 3 ... Yoke part 4 ... T joint part 5 ... Corner part 11 ... Magnetic core steel plate of iron core middle leg 12 ... Magnetic steel plate of iron core outer leg 13 ... Magnetic steel plate of yoke part B ₁₃ … Step width at T junction B ₂₃ … Step width at corner

Claims (3)

[Claims] 1. On both sides of an iron core middle leg on which hexagonal magnetic steel sheets having a tip portion at an angle of 90 ° are laminated at both ends in the length direction, from the tip toward the inside facing the iron core middle leg in parallel. An iron core outer leg having a trapezoidal magnetic steel plate having a tip portion at an angle of 45 ° is arranged, and a central portion of the trapezoid having an end portion at an angle of 45 ° from the tip toward the inner side facing the iron core outer leg at both ends. A magnetic yoke is formed by laminating a magnetic steel plate having a V-shaped cutout portion at an angle of 90 ° that is joined to the tip portion at an angle of 90 ° of the iron core middle leg to the magnet portion by joining the upper or lower portion of the iron core leg. In the three-phase three-leg iron core of the transformer that formed the path,
The step width between the magnetic steel sheet of the iron core middle leg and the magnetic steel sheet of the yoke portion at the T joint, which is the joint portion of the iron core middle leg and the yoke portion, is defined as the corner portion which is the joint portion of the iron core outer leg and the yoke portion. The step width of the magnetic steel plate of the outer core of the iron core and the magnetic steel plate of the yoke part is smaller than the step width, and the magnetic steel plates of the core middle leg and the outer core of the iron core and the magnetic steel plate of the yoke part are laminated. Instrument iron core. 2. On both sides of an iron core middle leg, which is formed by laminating hexagonal magnetic steel plates each having a tip end portion with an angle of 90 ° at both ends in the length direction, 45 from the tip toward the inside facing the iron core middle leg.
And a trapezoid having an iron core outer leg formed by laminating trapezoidal magnetic steel plates having an end portion at an angle of 45 °, and an end portion at an angle of 45 ° from the tip toward the inside facing the outer core legs at both ends. A magnetic steel sheet having a V-shaped cutout portion at a 90 ° angle to be joined to the tip portion at a 90 ° angle in the central portion of the core core and joined to the upper or lower portion of the iron core leg by a yoke portion. In the three-phase three-leg iron core of the transformer with the magnetic path formed, the step width between the magnetic steel plate of the iron core middle leg and the magnetic steel plate of the yoke portion at the T joint that is the joint between the iron core middle leg and the yoke , The step width between the magnetic steel plate of the outer core of the iron core and the magnetic steel plate of the yoke part at the corner part which is the joint part of the iron core outer leg and the yoke part, and the number of steps of the magnetic steel plate of the T joint part The number of steps of the magnetic steel plate in the Transformer core, characterized in that by laminating magnetic steel plates of magnetic steel plates and yoke portion of the leg and the core outer legs. 3. An iron core middle leg having laminated hexagonal magnetic steel plates each having a tip portion at an angle of 90 ° at both ends in the lengthwise direction, on both sides of the iron core middle leg, facing inwardly parallel to the iron core middle leg. An iron core leg having an iron core outer leg formed by laminating trapezoidal magnetic steel plates having an end portion at an angle of 45 °, and an end portion at an angle of 45 ° from the tip toward the inner side facing the iron core outer leg at both ends. Joined to the upper or lower part of the core leg by a yoke part in which a magnetic steel plate having a V-shaped cutout part at an angle of 90 ° which is joined to the tip part of the core leg of the core at the central part of the trapezoid is laminated In a three-phase three-leg iron core of a transformer that has formed a magnetic path, the step width between the magnetic steel sheet of the iron core middle leg and the magnetic steel sheet of the yoke portion at the T joint, which is the joint between the iron core middle leg and the yoke portion. Is the magnetic property of the outer core of the core at the corner, which is the joint between the outer core of the core and the yoke. The step width between the plate and the magnetic steel plate of the yoke part, the number of steps between the magnetic steel plate of the middle core leg of the T-joint and the magnetic steel plate of the yoke part, and the joint part of the outer core leg and the yoke part The same number of steps as the magnetic steel plate of the outer core of the iron core and the magnetic steel plate of the yoke part in the corner part is the same number, and the magnetic steel plates of the corner part of the yoke part are laminated by changing the length by several. Characteristic transformer core.