JPH04345009A - Reactor iron core with cavity and manufacture thereof - Google Patents

Abstract

PURPOSE:To facilitate the manufacture of a ring type block iron core comprising the leg part of a reactor iron core while easily and surely avoiding the short circuit due to the burs caused during the cutting off step of a magnetic body. CONSTITUTION:A thin amorphous magnetic alloy band A is spirally wound up so as to compose a ring type block iron core B. Next, a slit part SL extending along a spiral curve from the inner peripheral side to the outer peripheral side is provided in the block ion core B.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core for a core reactor with a gap and a method for manufacturing the same.

0002

[Prior art] The magnetic circuit of an air-gap iron core reactor is
Legs (rims) in which magnetic material and air gaps are repeatedly connected in series
and a yoke made only of magnetic material disposed at both ends of the leg. A single magnetic body separated by a gap in the leg is called a block core.

[0003] One block core has a thick cylindrical shape with a short axial length, and the space inside the core is used as a space for passing bolts for tightening the core.

Magnetic flux flows through the block core in the axial direction, and the three phases of magnetic flux merge at the yoke, but a radial component of the magnetic flux is generated due to fringing at the axial end of the block core. That is, at the axial ends of the block iron core, the magnetic flux near the outer periphery of the block iron core bulges toward the outer radial direction, and the magnetic flux near the inner periphery of the block iron core bulges toward the inner radial direction.

In order to suppress iron loss due to this magnetic flux fringing, the structure of the block core is such that the magnetic unit plates constituting each block core are arranged radially around the central axis with the magnetic unit plates oriented approximately in the radial direction. The mainstream configuration is A block core with such a configuration is called a radial core.

[0006] Here, the magnetic unit plate is the smallest unit of magnetic substance in a magnetic circuit, and in a radial core type block iron core, a rectangular silicon steel plate is used as the magnetic unit plate. In a radial core type block core, magnetic unit plates are assembled to form a fan-shaped sector, and a plurality of sectors are assembled to form a block core.

FIG. 8 is a partial plan view of a radial core type block iron core B1 composed of an aggregate of sectors Sr1. Each sector Sr1 is composed of a large number of magnetic unit plates U11, U12, . . . having different lengths. In FIG. 8, magnetic unit plates are illustrated for only two sectors, and illustration of magnetic unit plates for other sectors is omitted.

In FIG. 8, four types of magnetic unit plates having different dimensions are used, but in an actual air-gap iron core reactor, several dozen types of magnetic unit plates are used.

[0009] Furthermore, in an actual air-gap core type reactor, there are several thousand magnetic unit plates constituting one block core, and the reactor as a whole has tens of thousands to hundreds of thousands of magnetic unit plates. board is used.

FIG. 9 is a partial plan view showing a radial core type block core different from that shown in FIG. 8 in the same manner as in FIG. has been done. Here, if the lengths of the magnetic unit plates U21, U22,..., U2n are L21, L22,..., L2n, then L21+L
The relationship is 2n=L22+L2(n-1)=...=W.

The magnetic unit plate of the block core shown in FIG. 9 is made by cutting a material roll of width W into two in the width direction with a very gentle taper, and then cutting the material roll into two pieces in the width direction, and then cutting the material roll into two parts along the length direction of the material roll. Manufactured by cutting each length (axis length).

Next, a conventional example of the spiral core type will be described. As a spiral core type block iron core, as shown in Japanese Patent Publication No. 60-47731,
A slit is formed by cutting a wound body formed by spirally winding a silicon steel strip in the stacking direction at one point, and a wedge-shaped insulator is inserted into this slit from the outside diameter direction to the inside. has been proposed.

FIG. 10 is a plan view of the block core proposed in Japanese Patent Publication No. 60-47731.
3 is a wound body of silicon steel strip cut at one point in the circumferential direction, and a wedge-shaped insulator I3 is inserted into a slit portion SL3 created by the cutting. When the wound body of silicon steel strip is cut, both sides of the cut portion of the slit portion SL3 are parallel to each other, but by inserting the wedge-shaped insulator I3, the gap between the cut surfaces is expanded toward the outer diameter side. The shape changes. This proposal aims to eliminate short circuits within the silicon steel strips due to burrs at the cut portion by causing relative movement in the circumferential direction between adjacent silicon steel strips by inserting the wedge-shaped insulator I3.

[0014] Furthermore, in Utility Model Application Publication No. 1823/1983, an amorphous magnetic alloy ribbon (hereinafter also simply referred to as a ribbon) is applied to a block core, and the middle of the winding thickness of the wound body of the ribbon is A block iron core has been proposed in which a silicon steel strip is wound and inserted into a section, and a layer of thin strip is divided and then cut in the radial direction to form a slit section. This proposal aims to reduce the eddy current loss caused by short-circuiting between the ribbons due to burrs generated during slit formation by dividing the ribbon layers with silicon steel strips.

[0015]

[Problem to be Solved by the Invention] In the case of a radial core type block iron core, an extremely large number and various types of magnetic unit plates (rectangular silicon steel plates) must be manufactured and assembled, resulting in a large number of manufacturing processes. There is a problem in that it requires a lot of man-hours and costs are high.

In addition, in the case of a spiral core type block core using a silicon steel strip, the axial direction of the block core is perpendicular to the rolling direction of the silicon steel strip, so that the magnetic flux flow along the rolling direction is There was a problem in that the characteristics of general silicon steel strip, which exhibits excellent magnetic properties, could not be utilized at all. Furthermore, since the silicon steel strip has a considerably low resistivity, when a spiral core type is used, there is a problem in that a large eddy current loss occurs due to fringing of the magnetic flux.

In the case of a spiral core type block core using an amorphous magnetic alloy ribbon, the loss is lower than when using a silicon steel strip, but short circuits due to burrs between the ribbons at the cutting part can be avoided. It has been difficult to effectively eliminate the problem between adjacent ribbons. For example, suppose that the structure shown in FIG. 10 is applied to a spiral core type using thin ribbons to eliminate short circuits between the thin ribbons due to burrs at the cut portion. In this case, if the central angle of the wedge-shaped insulator (the angle formed by both tapered side surfaces) is α, the thickness of the ribbon is t, and the deviation between adjacent ribbons due to insertion of the wedge-shaped insulator is d, then d= t・tan(α
/2). If α=10 degrees and t=30μm, d=
The deviation size is 2.6 μm, which is an extremely small value. It is difficult to expect that entanglement due to burrs between the ribbons will be resolved due to such a slight deviation. If the central angle of the wedge-shaped insulator is increased, the deviation dimension d will increase, but it is difficult to significantly increase the central angle, and if you dare to increase the central angle, the space in the slit will increase and the reactor This will lead to larger size.

An object of the present invention is to easily and reliably eliminate short circuits caused by burrs during cutting of magnetic material without requiring much time and effort in manufacturing the block core, and to maintain the original characteristics of the applied magnetic material. It is an object of the present invention to provide an iron-core reactor with a gap that can be utilized effectively, and a method for manufacturing the same.

[0019]

[Means for Solving the Problems] The present invention uses a spiral core type block iron core using an amorphous magnetic alloy ribbon. The block core used in the present invention is characterized by having a slit portion extending along a spiral curve from the inner circumferential side toward the outer circumferential side.

In each block core, the amorphous magnetic alloy ribbons in the inner layer portion and the outer layer portion are both divided into three layers in the axial direction, and the amorphous magnetic alloy ribbon in the intermediate layer portion is divided into three layers along the axial length of the block core. It is also possible to form an integral structure.

The block iron core described above can be manufactured as follows.

First, an amorphous magnetic alloy thin ribbon is wound to form a ring-shaped laminate, and with one point in the circumferential direction of the ring-shaped laminate being tightened and restrained in the lamination direction, the ring-shaped laminate is formed at the restrained portion. Cut the body in the stacking direction.

Next, while maintaining the restraint state of one of the restraint parts divided into two by cutting, the restraint state of the other one is released, and the ring-shaped laminate, which has been cut and has only one end restrained, is stretched in a straight line. Make a developed laminate.

Next, after restraining the thin strips of the expanded laminate at a location away from the restrained end of the expanded laminate, the restraint at one end of the expanded laminate is released, and the expanded laminate is shaped into a cylindrical shape. Then, the cut surfaces at both ends of the expanded laminate in the longitudinal direction are made to face each other to form a slit portion. The shape of this slit is
It has a shape that extends along a spiral curve from the inner circumferential side toward the outer circumferential side.

[0025]

[Function] As described above, when the slit portion is formed in a shape that extends along a spiral curve from the inner circumferential side to the outer circumferential side of the ring-shaped block iron core, the individual cut surfaces of the ribbon become larger in the circumferential direction. Since they are shifted, it is possible to prevent the ribbons from being short-circuited due to burrs generated when cutting the ribbons. Therefore, the possibility of local overheating of the iron core can be eliminated, and iron loss can be reduced. Furthermore, since the slit portion becomes longer, the bonding area of the slit portion becomes larger, and the bonding strength increases. Further, since the shape of the slit portion is curved, the strength against shear stress acting on the joint portion can be increased, and the mechanical strength of the block iron core can be increased.

[0026]

[Embodiment] Fig. 1 is a plan view showing a block iron core B according to an embodiment of the present invention. This block iron core is made of a ring-shaped amorphous magnetic alloy ribbon A, and A slit portion SL extending in a spiral curve shape from the circumferential side to the outer circumferential side is formed.

This block iron core is manufactured as follows.

First, as shown in FIG. 2, a ring-shaped laminate R is manufactured by winding an amorphous magnetic alloy ribbon A. In the step of forming the ring-shaped laminate R, the ribbon A is wound around the winding frame M, and when a predetermined winding thickness T is obtained, the winding frame is stopped to obtain the ring-shaped laminate R.

After forming the ring-shaped laminate R, the winding frame is removed from the laminate, and as shown in FIG. Apply holding plates H1 and H2, respectively. Then, the space between the two holding plates is tightened using a shako vise or the like (not shown), and the thin strips are restrained from moving relative to each other at this portion. FIG. 3 is a front view of the ring-shaped laminate, showing a state in which it is suspended with retaining plates H1 and H2 upward. Amorphous magnetic alloy ribbons have extremely poor rigidity, so
When hung like this, it deforms into a drooping shape due to its own weight.

Next, the ring-shaped laminate R is cut in the stacking direction along with the holding plates at the central portions of the holding plates H1 and H2 (portion Ct indicated by the chain line in FIG. 3). By this cutting, the holding plate H1
and H2 are the halves H11, H12 and H2, respectively
1, H22. Then, while keeping one half of the cut holding plate, for example, halves H11 and H21, in a tightened state, the other half of the holding plate H12 and H22 are unfastened, and both halves H12 and H22 are Remove from laminate.

Next, the ring-shaped laminate R cut at one point in the circumferential direction is stretched linearly to form a developed laminate S as shown in FIG. The cut surface at one end of the developed laminate S, which is restrained by the holding plate, is a surface (perpendicular cut surface) Sa that is perpendicular to the longitudinal direction of the developed laminate, and the cut surface at the other end is Slanted surface (slanted cutting surface) Sb
It becomes. The angle θ that the inclined cut surface Sb makes with the longitudinal direction of the developed laminate is θ=tan-1 (1/2π)
=9 degrees.

Next, the ribbon is restrained at a location a predetermined distance E away from the perpendicular cut surface Sa of the expanded laminate S (a location away from the already restrained end). Dashed line Cp in Figure 4
indicates this constraint location. This restraint is achieved by holding plates H1, H
2 can be used to restrain the ribbon, but the holding plate (not shown) used at this time is the holding plate H.
1, H2 may be smaller.

When the inner diameter of the ring-shaped laminate is D, the maximum value of the distance E from the right-angled cut surface Sa to the constraint point Cp is πD, and the constraint point C can be placed at any position within this range.
p can be set. In the example shown in Figure 4, E=
(πD)/2. That is, the laminate is tightened and restrained at the midpoint of the upper side (short side) of the developed laminate S.

Next, one half H11, H21 of the holding plate is removed, and while the spread stack S is restrained at the restraining point Cp, the spread stack is shaped into a cylindrical shape, and the stacked surfaces at both ends are shaped. By butting them together, block iron core B is obtained.

[0035] Since the ribbon of amorphous magnetic alloy has poor rigidity, it is easy to shape the expanded laminate S into a cylindrical shape.

When forming the block core, the short side of the developed laminate S is wound around an inner core (not shown) having approximately the same diameter as the winding frame M shown in FIG. 2, and shaped into a cylindrical shape. Then, wrap a suitable metal band (not shown) around the outer periphery to maintain its shape.

After magnetic field annealing, shaping members such as the inner core and band fittings are removed to obtain the block iron core shown in FIG. In this block core, the right-angled cut surface Sa and the inclined cut surface Sb of the expanded laminate S face each other, and the slit portion S
L is formed. A thin insulating layer is later inserted into this slit portion, and the insulating layer prevents the formation of a closed circuit in the circumferential direction of the block iron core.

The slit portion SL of the block core B has a spiral curve, and has a shape that curves and extends from the inner periphery toward the outer periphery of the core while being largely offset in the circumferential direction of the core. This means that the position of the ribbon restraint part when forming the expanded laminate S from the ring-shaped laminate R is different from the position of the ribbon restraint part when forming the block core B from the expanded laminate S. by.

If the shape of the slit portion SL is greatly deviated in the circumferential direction as shown in FIG. 1, the cut surfaces of the ribbons will be staggered from one ribbon to the next. There is no possibility that the ribbons will be short-circuited due to burrs or the like generated when cutting the R. Therefore, the core loss can be reduced compared to the case where the block core is constructed by cutting the ring-shaped laminate in the radial direction, and the risk of local overheating of the core can be eliminated. .

[0040] Here, the deviation dimension d for each ribbon is calculated as follows.

The inner diameter of the ring-shaped laminated body R is D, the laminated thickness is T, and the number of laminated ribbons is n, and these are the block iron core B.
The same shall apply. If the thickness of the ribbon is t, then T=n
It becomes t. The deviation dimension d between the kth thin ribbon and the k+1th thin ribbon from the inside is given by the following (1).

d={1−(h+k)/(h+k+1)}E
...(1) Here, h=D/(2t), and E is the distance dimension shown in FIG. As can be seen from equation (1), the deviation size decreases toward the outer layer of the block core. As a numerical example, D=12cm, T=12cm, t=30μm
, E=πD/2. Since h=2000, the deviation size d at the innermost layer of the ribbon is 94 μm, assuming k=1.

The dimension d of the outermost layer of the ribbon is k+1
=n, n= 120/0.03=4000, d=3
It becomes 1 μm.

Note that the above is the deviation dimension when E=πD/2, but the maximum possible value of E is applied (E=πD
), it is possible to obtain a displacement dimension twice the above-mentioned displacement dimension.

The deviation between the ribbons obtained by the method described above is the deviation between the ribbons obtained by inserting the wedge-shaped insulator I3 as shown in FIG. 30μm, the inclination angle of the wedge-shaped insulator is α=
It can be seen that when the angle is 10 degrees, the deviation size is much larger than 2.6 μm).

When constructing a reactor core using the above block core, an insulating layer made of kraft paper or the like is sandwiched between the slit portion SL, and a cylindrical inner frame F1 and outer frame F2 made of FRP or the like are respectively inserted. Attach to the inside and outside of the block core. Then, resin is impregnated with epoxy resin or the like in a vacuum, so that the resin is filled between the ribbons of the block core and between the insulation layer, the inner peripheral frame, the outer peripheral frame, and the ribbons. By curing this resin, as shown in FIG. 5, a block core structure Bc is formed in which the block core B, the insulating layer I, the inner frame F1, and the outer frame F2 are integrated. When the block core structure is hardened with resin in this manner, it becomes mechanically extremely strong and can withstand stress during core tightening even though the ribbon after annealing is extremely brittle.

FIG. 5 shows a longitudinal section of the block core structure Bc, and FIG. 5(a) shows the section of the block core structure along line a-a in FIG. This figure shows a cross section of . Further, FIGS. 5(b) and 5(c) are cross-sectional views including the slit portions of the block core structure taken along lines bb and cc in FIG. 1, respectively. Since the slit portion has a shape along a spiral curve, the radial position of the slit portion on the cut surface will differ if the cutting position is different.

[0048] In the block core according to the present invention, since the slit portion forms a spiral curve and extends for a long time, the joint state at the slit portion can be improved, and the mechanical strength of the block core structure can be increased. . this is,
In the case of a linear shape that does not deviate in the circumferential direction (in this case, the length of the slit part is the minimum), in the case of a slit part that is linear even if it deviates in the circumferential direction, and in the case of a spiral shape in the embodiment of the present invention. This will be better understood if you compare it with a curved slit section.

FIG. 6 shows a reactor core with a gap constructed using the block core structure Bc described above. In this example, the block core structure Bc is separated by a gap G maintained by arranging a spacer. The legs L are stacked up to form the legs L, and yokes Y made of delta-shaped annular iron cores are disposed at the upper and lower ends of the three-phase legs L, respectively. The yoke Y is a spiral core in which a silicon steel strip is wound, similar to the conventional reactor core with a gap. Note that in FIG. 6, only the core portion is shown, with the windings and core tightening bolts omitted.

Since the block iron core in the present invention is of the spiral core type, it is not necessary to combine a large number of magnetic unit plates as in the case of a radial core type block iron core, and the number of man-hours for manufacturing the iron core can be reduced.

When a spiral core type block iron core is constructed using an amorphous magnetic alloy ribbon as in the present invention, the electrical and magnetic characteristics of the ribbon can be well exhibited. The reasons for this will be summarized below.

In a general silicon steel strip, the iron loss when the magnetic flux is passed in the width direction of the material roll (direction perpendicular to the rolling direction) is the same as the iron loss when the magnetic flux is passed in the length direction (the rolling direction) of the material roll. It reaches about four times as much as before. However, in the case of amorphous magnetic alloy ribbon, at the material stage, there is no particular directionality in core loss when magnetic flux is passed parallel to the ribbon, and magnetic properties in any direction can be selectively changed by magnetic field annealing. can be improved. That is, the magnetic properties are selectively improved in the direction of the magnetic flux passed during magnetic field annealing. The iron loss in the specific direction improved in this way is about 1/4 of the iron loss in the rolling direction of a general silicon steel strip (based on the standard magnetic flux density).

[0053] Also in the iron core according to the present invention, it is preferable to selectively improve the magnetic properties in the axial direction of the block iron core by magnetic field annealing. As a specific example of the magnetic field annealing method, there is a method in which a block iron core is coaxially disposed within a poloidal coil and annealing is performed while the poloidal coil is energized. The iron loss of the block iron core according to the present invention obtained in this way is a fraction of the iron loss of a radial core type block iron core using silicon steel strip (1/4 according to the data standard mentioned above).
), which is about one-tenth (1/16 according to the above-mentioned standard) of the core loss of a spiral core type block core using a silicon steel strip.

In the above explanation, iron loss is compared without taking into account the effect of fringing of magnetic flux, but in reality iron loss is due to fringing of magnetic flux. That is, in the case of a spiral core type block iron core, an eddy current is generated along the plate surface of the magnetic material due to the radial component of the magnetic flux generated by fringing. However, the specific resistance of an amorphous magnetic alloy ribbon is nearly three times that of a silicon steel strip, so if an amorphous magnetic alloy ribbon is used in a spiral core type block core, it is difficult to use a silicon steel strip. This makes it more difficult for eddy currents to flow than in the conventional case, and it is possible to significantly reduce iron loss due to fringing of magnetic flux.

FIG. 7 is a cross-sectional view showing another embodiment of the present invention, and is a longitudinal cross-sectional view of a portion of the block iron core that does not cover the slit portion. In this example, the block core is
Inner layer portion (portion closer to the inner periphery) Bi, middle layer portion Bm
and an outer layer portion (a portion closer to the outer periphery) Bo, and the ribbon is divided into three parts in the axial direction in the inner layer portion Bi and the outer layer portion Bo. The intermediate layer portion Bm is not divided in the axial direction and has an integral structure over the entire length in the axial direction.

Each of the divided cores in the inner layer portion and outer layer portion, as well as the core in the intermediate layer portion, will be referred to as partial block cores.

The partial block iron core constituting the intermediate layer portion Bm is assumed to be Bp1. Among the three partial block cores constituting the inner layer portion Bi, the two partial block cores on the axial end side are designated as Bp2, and the partial block core on the axial center portion is designated as Bp3.

Of the three partial block cores constituting the outer layer portion Bo, the partial block core on the axial end side is Bp.
4, and the partial block iron core at the center in the axial direction is Bp5.

A blind-shaped insulator I1 is provided between the partial block cores Bp2 and Bp3. Similarly, a blind-shaped insulator I1 is also provided between the partial block cores Bp4 and Bp5. The blind-shaped insulators I1 are plate-shaped insulators arranged at intervals along the circumferential direction of the block core. By arranging the interdigital insulator in this way, the resin can move between the partial block cores through the spaces of the interdigital insulator during resin impregnation, so that the resin can be infiltrated into the entire block core.

As in this embodiment, if the ribbon is divided in the axial direction in the inner layer portion Bi and outer layer portion Bo of the block core, loss due to magnetic flux fringing can be extremely reduced. The reason for this is outlined below.

Magnetic flux φ0, φ1, φ2 shown in FIG.
conceptually shows the behavior of magnetic flux in a block core. φ0 is a magnetic flux flowing through the intermediate layer portion of the block iron core, and this magnetic flux flows linearly in the axial direction. φ1 is a magnetic flux flowing through the inner layer of the block core, and this magnetic flux is bent in the inner radial direction by fringes near the axial end of the block core. Also φ2
is the magnetic flux in the outer layer portion of the block core, which is bent in the outer radial direction due to fringing near the axial end of the block core.

The radial components caused by the fringing of the magnetic fluxes φ1 and φ2 produce eddy currents within the ribbon. The direction of this eddy current is that at the axial end on the inner layer portion Bi side, the current direction at both ends is the same, and the direction of the current at both ends is the same, and the direction of the current at the outer layer portion Bo
Even at the axial end portions of the side, the direction of the current at both ends is the same. The directions of the eddy currents on the inner layer portion Bi side and the outer layer portion Bo side are opposite to each other.

[0063] Here, assuming that the ribbon is not divided in the axial direction on the inner layer portion Bi side of the block core,
Eddy currents flowing in the same direction at both ends in the axial direction change direction in the axial direction at the slit portion, merge at the center in the axial direction, and flow in a direction opposite to the direction at the ends in the axial direction. However, as shown in Fig. 7, if the block core is divided in the axial direction, the eddy current must circulate within the block core on the axial end side, so the eddy current loop becomes smaller and the eddy current The size also becomes smaller. Therefore, eddy current loss can be reduced.

The above describes the outer layer portion B of the block iron core.
The same applies to the o side. Therefore, by dividing the ribbon in the axial direction on the inner layer side and the outer layer side of the block core as shown in FIG. 7, iron loss due to fringing of magnetic flux can be significantly reduced.

[0065] It should be noted that simply dividing the ribbon does not necessarily result in the effect of reducing iron loss. For example, even if the ribbon is divided at the axial center of the block core, no iron loss reduction effect can be obtained. The key point in dividing the thin ribbon is to divide it near a portion where a radial component of the magnetic flux is generated due to fringing of the magnetic flux. In order to satisfy this condition, it is necessary to divide it into at least three parts in the axial direction. In order to reduce iron loss, increasing the number of divisions in the axial direction (for example, dividing the partial block core into two) will further increase the effect, but increasing the number of divisions will weaken the block core mechanically. , since it takes a lot of man-hours to manufacture, in practice it is difficult to use Figure 7.
It is a good idea to divide it into three parts as shown in the figure.

[0066]

[Effects of the Invention] As described above, according to the present invention, a spiral type ring-shaped block iron core made of an amorphous magnetic alloy ribbon extends along a spiral curve from the inner circumferential side to the outer circumferential side. Since the shaped slit portions are formed, the individual cut surfaces of the ribbon can be largely shifted in the circumferential direction to prevent short circuits between the ribbons due to burrs generated when cutting the ribbon. Therefore, the possibility of local overheating of the iron core can be eliminated, and iron loss can be reduced.

Further, according to the present invention, since the slit portion becomes longer, there is an advantage that the bonding area of the slit portion can be increased and the bonding strength can be increased.

Further, in the present invention, since the shape of the slit portion is curved, the strength against shear stress acting on the joint portion can be increased, and the mechanical strength of the block iron core can be increased.

Furthermore, in the present invention, since the ribbon of amorphous magnetic alloy is used, the magnetic properties in the direction of passing magnetic flux can be selectively improved during magnetic field annealing, and the block iron core can be improved during magnetic field annealing. By selectively improving the axial magnetic properties of the amorphous magnetic alloy,
A low-loss iron core can be obtained.

Furthermore, in the method of the present invention, a block iron core is formed from the developed laminate by using a new ribbon constraint at a location different from the constraint part of the ribbon when forming the developed laminate from the ring-shaped laminate. Therefore, a block core having a long curved slit portion can be easily manufactured, and the number of man-hours required for manufacturing the core can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a block iron core in an embodiment of the present invention.

FIG. 2 is an explanatory view showing a step of manufacturing a ring-shaped laminate by winding an amorphous magnetic alloy ribbon in the manufacturing method of the present invention.

FIG. 3 is a front view showing a state in which a part of the ring-shaped laminate is restrained in the manufacturing method of the present invention.

FIG. 4 is a front view of a developed laminate formed in an example of the manufacturing method of the present invention.

[Fig. 5] (a), (b), and (c) show the block core structures used in the embodiments of the present invention at the a-a line, the bb line, and the c-c line of the block iron core in Fig. 1, respectively. FIG.

FIG. 6 is a perspective view showing the appearance of a main part of a reactor core according to an embodiment of the present invention.

FIG. 7 is a longitudinal cross-sectional view of a main part of a block core structure used in another embodiment of the present invention.

FIG. 8 is a plan view showing a part of a conventional radial core type block iron core.

FIG. 9 is a plan view of main parts showing another example of a conventional radial core type block iron core.

FIG. 10 is a plan view of a main part showing a conventional spiral core type block iron core.

[Explanation of symbols]

A... Amorphous magnetic alloy ribbon, R... Ring-shaped laminate, S... Expanded laminate, B... Block core, Bc... Block core structure, Bi... Inner layer portion, Bm... Intermediate layer portion, Bo...
Outer layer part, Bp1 to Bp5...partial block iron core, SL
, SL3...Slit portion, F1...Inner peripheral frame, F2...Outer peripheral frame, I...Insulating layer, I1...Blind-shaped insulator, I3...Wedge-shaped insulator, L...Leg part, Y...Yoke, G...Gap, Sr1,
Sr2...sector, U11, U12,..., U21, U2
2...Magnetic unit plate.

Claims (3)

[Claims] 1. A reactor core with a gap, in which a plurality of ring-shaped block cores made of wound bodies of amorphous magnetic alloy thin strips are stacked in the axial direction to form legs, wherein the block core has an inner periphery. A reactor core with a gap characterized by having a slit portion extending along a spiral curve from the side toward the outer circumference. [Claim 2] Both the amorphous magnetic alloy ribbons of the inner layer portion and the outer layer portion of each block core are divided into three in the axial direction,
2. The reactor core with a gap according to claim 1, wherein the amorphous magnetic alloy ribbon in the intermediate layer portion is integrally formed over the entire length of the block core in the axial direction. 3. A ring-shaped laminate is formed by winding an amorphous magnetic alloy ribbon, and the ring-shaped laminate is tightened and restrained in the lamination direction at one point in the circumferential direction of the ring-shaped laminate. The ring-shaped laminate is cut in the stacking direction, and one of the restrained parts divided into two by the cutting is released from the restrained state while maintaining the restrained state of the other, and the ring-shaped body is cut and only one end is restrained. The laminate is stretched linearly to form a developed laminate, and after restraining the thin strips of the developed laminate at a location away from the restrained end of the developed laminate, the restrained state of one end of the developed laminate is The expanded laminate is released, shaped into a cylindrical shape, and the cut surfaces at both ends of the expanded laminate in the longitudinal direction are opposed to each other to form a slit, thereby creating a spiral shape from the inner circumferential side to the outer circumferential side. A method for producing a reactor core with a gap, the method comprising obtaining a block core having a slit extending along a curve.