JPH04192510A - Iron core type reactor with gap - Google Patents

Abstract

PURPOSE:To reduce loss in a magnetic block itself in order to lower eddy current loss and stray loss due to leakage magnetic flux by inserting a magnetic block formed by sintering magnetic material powder to cover a winding between the end part of iron core legs and yoke iron core. CONSTITUTION:Iron core legs 3 with gap are formed by stacking a plurality of block iron cores 1 with a magnetic gap 2 and plate type magnetic blocks 9a, 9b obtained by sindering and molding magnetic material powder are sandwiched from upper and lower yoke iron cores 5a, 5b at the upper and lower ends of the iron core legs 3 to cover a winding 6 together with the right and left side legs 4. Therefore, a volume resistivity of magnetic blocks 9a, 9b is as large as 10<6> or larger and an eddy current loss can be neglected for the magnetic flux of commercial frequency range. Accordingly, overheat of the magnetic blocks 9a, 9b are not considered as a problem and sufficiently plays a role for uniformly applying the magnetic flux in the ununiform distribution from the block iron core 1 and winding 6 to the yoke iron cores 5a, 5b. Thereby, loss in magnetic block itself is reduced and eddy current loss, stray loss due to magnetic flux can be lowered.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a gapped core reactor equipped with magnetic prosters arranged at the upper and lower ends of a block core to control the flow of magnetic flux. Regarding.

(Prior Art) As a reactor used for a shunt reactor or the like, an iron core reactor with a gap has been generally used. This gapped core type reactor consists of a plurality of circular block cores formed by laminating silicon steel strips, which are stacked together via multiple magnetic gaps to form gapped core legs. A yoke core also formed by laminating silicon steel strips is disposed, and windings are wound around the core legs. A gap member made of an insulator is generally interposed in the gap portion. In such a gapped core reactor, a part of the magnetic flux flowing within the block core and between the block core and the winding enters the clamping member of the yoke core as leakage flux, causing eddy current to be generated locally. This may cause an excessive temperature rise and result in loss.

In addition, since the cross-sectional shape of the block core is approximately circular, the amount of magnetic flux that enters the yoke core of the same width from the block core in the stacking direction is maximum at the center of the yoke core in the stacking direction. The amount of incident magnetic flux decreases toward the outside in the stacking direction. Therefore, when the magnetic flux that has flowed into the yoke iron core flows through the yaw iron core and the side legs, it flows from the central silicon steel band where the magnetic flux density is high to the outer silicon steel band where the magnetic flux density is low. As the magnetic flux flows between the silicon steel strips in the direction of the strip thickness, large eddy currents are generated in the silicon steel strips, increasing loss, and causing damage between the yoke core and the side legs. There is also a possibility that current will flow locally at the contact area, causing abnormal overheating.

Therefore, when it comes to large-capacity acdles, the top of the winding,
Some have a magnetic block made of ferromagnetic material that passes through the core window at the lower end at a distance necessary for spatial insulation. As this type of magnetic block, US Pat.
Publication No. 7,025 (see Figure 3) and Utility Model Publication No. 61-112
There is one disclosed in Publication No. 625 (see Figure 4).

(Problem to be solved by the invention! III) The magnetic block 10 in the example shown in FIG. An insulator I3 is placed between the yoke core 11 and the block core I2 so that the stacking direction is horizontal.
It is sandwiched through. Due to this magnetic block, the magnetic flux directed from the block core 12 or the winding (not shown) toward the yoke core 11 flows within the magnetic block 10 so as to have a uniform magnetic flux distribution in the stacking direction of the yoke core 11. However, in the magnetic block IO having this structure, since the flat part of the silicon steel strip is located inside the core window, there is a risk of overheating due to fringing magnetic flux at the end of the winding.

Fig. 4 has been proposed for the purpose of improving the above-mentioned drawbacks, and by forming a magnetic block 21 by laminating silicon steel strips 20 cut into rectangular strips in a radial manner, This is to prevent overheating due to magnetic flux. However, in a magnetic block with this structure,
Make the magnetic flux uniform in the stacking direction of the yoke core#
It has the disadvantage that its performance is insufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gapped iron-core reactor that eliminates the above drawbacks, reduces loss in the magnetic block itself, and further reduces eddy current loss and stray loss due to leakage magnetic flux.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, in the present invention, the magnetic block is formed of ferrite obtained by sintering and molding powder magnetic material.

(Function) Since the magnetic block is made of ferrite formed by sintering and molding powder magnetic material, the volume resistivity of the magnetic block is extremely high, exceeding 106 of that of metal.
Eddy current losses can be ignored for magnetic flux in the commercial frequency range. Therefore, overheating of the magnetic block is not a problem at all, and the function of uniformly injecting the non-uniformly distributed magnetic flux from the block core and the windings into the yoke core can be fully achieved.

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

In FIGS. 1 and 2, a plurality of block cores 1 are stacked with magnetic gaps 2 in between to form gapped core legs 3, and powder magnetic material is sintered at the upper and lower ends of the core legs 3. Finally, place the molded plate-shaped magnetic blocks 9a and 9b on the left.
It is inserted between the yoke cores 5a and 5b from above and below so as to cover at least the winding 6 together with the right side leg 4.

Between the block iron core 1 and the magnetic block 9a and between the magnetic block 9a and the upper yoke iron core 5a, since the volume resistivity of the magnetic block 9a is extremely large, interlayer short circuits of the yoke iron core 5a and the block iron core 1 are prevented. Although an insulating plate is not necessary, a thin buffer plate may be inserted to avoid local stress concentration due to irregularities in the laminated surfaces of the silicon steel body. The same applies to the space between the lower yoke core 5b and the magnetic block 9b.

With this configuration, the magnetic flux flowing from the block iron core l to the yoke iron cores 5a, 5b fringes outward and enters the magnetic blocks 9a, 9b from any direction, reducing the volume of the magnetic blocks 9a, 9b themselves. Since the resistivity is extremely high, there is no need to worry about overheating. Also magnetic bronc 9a.

Since 9b is non-directional, it is a magnetic block 9a.

The magnetic flux incident on the magnetic blocks 9b can freely flow in any direction within the magnetic blocks 9a, 9b, and the yoke cores 5a,
The magnetic flux flowing into the magnetic blocks 9a and 9b flows in such a manner that the magnetic flux distribution flowing into the magnetic blocks 5b becomes uniform in the stacking direction. Therefore, the occurrence of loss due to the flow of magnetic flux between the laminated silicon steel bands in the yoke cores 5a, 5b, and the occurrence of overheating due to local eddy current flow at the joints between the yoke cores 5a, 5b and the side legs 4 are also suppressed. can.

In addition, conventional magnetic blocks were formed by laminating several thousand thin rectangular silicon steel strips with a thickness of about 0.3 mm and fixing them with adhesive. Although it took a lot of time, the magnetic block according to the present invention can be easily manufactured by sintering powder magnetic material and integrally molding it.

〔Effect of the invention〕

As described above, a plurality of block cores are stacked together via a magnetic gap member to form a core leg, a winding is wound around this core leg, and this core leg is connected to a yoke core from above and below along with side legs. In a sandwiched gap iron core type reactor, a magnetic block formed by sintering powder magnetic material is inserted between the end of the iron core leg and the yoke iron core so as to cover at least the winding wire. Therefore, it is possible to obtain a gapped iron-core reactor in which the loss of the magnetic block itself is reduced, and the eddy current product and stray loss due to leakage magnetic flux are further reduced.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a side view of the same, Fig. 3 is a perspective view of an axle using a conventional magnetic bronch, and Fig. 4 is a perspective view of another conventional magnetic block. FIG. DESCRIPTION OF SYMBOLS 1...Block core, 2...Gap, 3...Core legs, 5a, 5b...Yoke core, 6...Winding, 9
a, 9b...magnetic block. Applicant's agent Patent attorney Takehiko Suzue 3
5b Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A plurality of block iron cores are stacked together via a magnetic gap member to form a core leg, and a winding wire is wound around this core leg,
In a gap core type reactor in which this core leg is sandwiched between the yoke core from above and below along with the side legs, powder magnetic material is placed between the end of the core leg and the yoke core so as to cover at least the winding. An iron core reactor with a gap made by inserting a sintered and formed magnetic block.