JPH03203207A - Manufacture of wound iron core and its tearing - Google Patents

Abstract

PURPOSE:To prevent generation of burrs and harmful pieces by applying tensile force on a weak point part for tearing during an annealing process after winding and shaping a magnetic band. CONSTITUTION:Following a temperature rise in an annealing furness, expansion bodies 31 inside the respective expansion containers 32 in an expansion in an expansion mechanism 28 is heated and expanded. Since pressure inside the respective expansion containers 32 rises by expansion of the expansion bodies 31, the respective expansion container 32 expands so that especially their end surface parts 32 is outwardly widened to push out a cylinder 30 in the arrow A direction. Subsequently, a wedge mold 35 is pushed and moved in the same direction and this wedge mold 35 pushes expansion molds 34, 34 in the arrow B direction respectively so that expansion force acts on an equivalent part to an iron core window of a wound iron core 21 in the direction to expand these. Thereby, tensile force in the arrow B direction acts on the respective weak point parts 23a of a magnetic band 23a. Since, moreover, at this time the respective weak point parts 23a are weakened by heat, the weak point parts 23a are easily torn as desired by the tensile force.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention provides a method for manufacturing a wound core in which a one-turn cut type wound core is manufactured by tearing a magnetic band after winding it up, and Regarding the disconnection device.

(Prior art) Traditionally, the production of this kind of winding core has been carried out in the
There is one shown in Japanese Patent No. 6088.

As shown in FIG. 6, a magnetic strip (generally a silicon steel strip) 1 is stepped at predetermined positions in the winding direction using an upper blade 2 and a lower blade 3 to form thin weak points 4. After shaping and winding it around the winding shaft 5, it is removed from the winding shaft 5, formed into a rectangular shape, annealed, and then the thickness of the roll is adjusted using a supporting mold 6 and a pressing mold 7 as shown in FIG. By applying pressure in this direction, the weak point portion 4 is torn and a one-turn cut type wound core is manufactured.

(Problem to be Solved by the Invention) In the case described above, as shown in FIG.
The thickness of the plate is t. , where the film thickness of the weak point 4 is t1 and the remaining thickness of the weak point 4 is t2, it is expressed as t2+xjo-t, where t is the plate thickness of the magnetic band 1 of 12 parts of the remaining thickness of the weak point 4. The overall survival rate α is expressed by the following formula.

α-(t2/1o) It requires force, and in order to tear it under the pressure of the supporting die 6 and the pushing die 7, the survival rate α of the weak point 4 is as small as possible, especially 10
It is preferable to set the value to [%] or less.

However, if the survival rate α of the weak point portion 4 is reduced in this way, the magnetic band 1 may be torn during winding, making winding impossible.

Therefore, the survival rate α of the weak point 4 is actually 20[%]
We are trying to secure the above value.

However, if a large survival rate α of the weak point 4 is ensured, the above-mentioned clamping pressure cannot reliably tear the weak point 4, and in particular, the weak point 4 can be broken as shown in FIG. This often caused the problem that it would only deform, but not break.

Therefore, as shown in FIG. 11, a pair of expansion molds 9 are inserted into the core window equivalent portion 8 of the magnetic band 1 after forming and annealing.
A method was devised in which a wedge mold 10 is driven between the expansion molds 9 to apply a tensile force to the weak point 4 and cause it to tear.

According to this method, the force applied to the weak point 4 is greater than the method using the above-mentioned clamping pressure, and therefore the weak point 4 can be torn more reliably than the method using the clamping pressure. however,
If this method is used, although it is possible to tear the parts, as shown in FIG. During this process, the iron core detaches from the core and enters between the winding layers of the coil, causing dielectric breakdown.

The present invention has been made in view of the above-mentioned circumstances, and therefore, its purpose is to prevent the tearing of weak points after winding up a magnetic band.
It is an object of the present invention to provide a method for manufacturing a wound core and a tearing device thereof, which can be carried out in a very convenient manner without producing any harmful fragments.

[Structure of the Invention] (Means for Solving the Problems) The method for manufacturing a wound core of the present invention involves forming a weak point at each predetermined position in the winding direction and winding the magnetic strip, and then winding the magnetic strip into a predetermined shape. By tearing the weak point after molding,
In a method of manufacturing a one-turn cut type wound core,
The magnetic band is characterized in that during the annealing step after winding and forming the magnetic band, a tensile force is applied to the weak point to cause it to tear.

As mentioned above, the device for tearing the weak point of the magnetic band during the annealing process is an expansion mechanism that expands when heated, and a device installed in the part of the magnetic band corresponding to the iron core window after forming. It is preferable that the expansion type device is configured to apply an expansion force to a portion corresponding to the iron core window in response to the expansion force from the fat expansion mechanism, thereby applying a tensile force to the weak point of the magnetic band.

(Function) The weak points of the magnetic band become brittle due to the high temperature during the annealing process.
Since a tensile force is applied to the weak point in this state, compared to applying a tensile force to the weak point at room temperature,
The weak point can be easily torn, and therefore the weak point can be torn without creating any debris.

In the device for tearing the weak point of the magnetic band, the expansion mechanism expands due to the heat during the annealing process, and in response to the expansion force, the expandable device applies an expansion force to the part of the magnetic band corresponding to the iron core window. By applying a tensile force to the weak point of the magnetic band,
With this, the weak point can be torn off in a very good manner.

(Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

First, in FIGS. 1 and 2, the wound core 21 before annealing is made of a magnetic band 22 made of, for example, a silicon steel strip, as in the conventional case (see FIG. 6), and has weak points at predetermined positions in the winding direction. A portion 23 is formed and wound up, and this is formed into a long rectangular shape, and has a core window equivalent portion 24 in the center, and the weak points 23 are positioned in a stepped manner on one short side 21a. ing.

A support plate 25 and a backing plate 26 are arranged on the inner and outer sides of the other short side 21b of the wound core 21, and these are connected by bolts 27. A fat expansion mechanism 28 is disposed approximately at the center of the core window equivalent portion 24. As shown in FIG. 3, this fat expansion mechanism 28 consists of two cylindrical cases with one end closed, and
A cylinder 30 is inserted into the case 9 from the opening side in a rotatable and axially movable state, and a cylinder 30 is disposed between the case 29 and the cylinder 30 and expands when heated inside. It is composed of a plurality of fat expansion containers 32 in which fat expansion bodies 31 are enclosed. A convex portion 29a is formed on the end surface of the case 29 on the closed side, and this convex portion 29a is fitted into a hole 25a formed in the support plate 25. A threaded portion 30a having a male thread formed on the outer peripheral surface is protruded from the tip of the cylinder 30. Also,
The expanded fat container 32 has a peripheral wall 32a with a thickness equal to that of the end surface 32.
The peripheral wall portion 32a is formed to be larger than the wall thickness b, and the peripheral wall portion 32a is configured to be difficult to deform while the end surface portion 32b is configured to be easily deformed outward when the expanded fat body 31 is expanded.

Furthermore, an expandable device 33 is disposed on one of the short sides 21a of the core window equivalent portion 24. This expandable mold device 33 is composed of a pair of expandable molds 34.34 arranged along both left and right long sides 21c and 21d, and a wedge shape 35 arranged between these expandable molds 34.34. There is. Of these, each of the expansion molds 34, 34 is connected by a bolt 37 to a clamping plate 36, 36 arranged to sandwich the corresponding long side. The wedge shape 35 has one short side 21a.
It is connected by bolts 39 to a backing plate 38 arranged to sandwich the two. Further, a screw hole 35a is formed in the center of the wedge shape 35, and the screw portion 30a of the cylinder 30 is screwed into this screw hole 35a.

Here, the fat expansion mechanism 28, expandable device 33, etc. are assembled to the wound core 21 in the following manner.

First, the long sides 21c and 21d of the wound core 21 are tightened and fixed by inserting the pair of expansion molds 34, 34 into the core window equivalent portion 24 and connecting them with the clamping plates 36 and bolts 37, respectively. Then, by inserting the support plate 25 into the other short side 21b of the core window equivalent portion 24 and connecting it to the backing plate 26 with bolts 27, the short side 21b is tightened and fixed.

The wedge mold 35 is then inserted between the expanded molds 34,34. Then, the fat expansion mechanism 28 is inserted into the core window equivalent part 24, and the two convex parts 29a of the case are inserted into the holes 25a of the support plate 25.
At the same time, the threaded portion 30a of the cylinder 30 is threaded into the threaded hole 35a of the wedge shape 35. At this time,
The amount of insertion of the threaded portion 29a into the threaded hole 35a is adjusted as appropriate.

In this way, the assembly of the fat expansion mechanism 28, expandable device 33, etc. to the wound core 21 is completed.

Now, the above-mentioned wound core 21. In order to perform the annealing, the wound core 21 with the fat expansion mechanism 28, the expandable device 33, etc. assembled as described above is placed in an annealing furnace (not shown) and heated. In this case, the maximum temperature during annealing is usually about 800°C.

As the temperature in the annealing furnace increases, the fat expansion bodies 31 in each fat expansion container 32 in the fat expansion mechanism 28 are heated and expanded.

Since the pressure inside each fat expansion container 32 increases due to the expansion of the fat expansion body 31, each fat expansion container 32 is particularly
The cylinder 30 expands outward as shown in FIG. 4, and the cylinder 30 is pushed out in the direction of arrow A. Along with this, the wedge shape 35 is pressed and moved in the same direction, and the wedge shape 35 pushes the expansion molds 34 and 34 in the direction of arrow B, respectively, and expands them into the core window corresponding part 24 of the wound core 21. Expansion force in the direction of

As a result, a tensile force in the direction of the arrow B acts on each weak point 23 of the magnetic band 22, and since each weak point 23 is weakened by heat at this time, the weak point 23 is affected by the tensile force. Easily torn. Figure 4 shows weak point 2.
3 shows a torn state (torn part 23a). The cracking of this weak point 23 occurs from the inner circumferential side of the wound core 21 on the side corresponding to the core window 24 and progresses to the outer circumferential side in a chain reaction, and during the annealing process, all weak points 23 rupture is completed.

In this way, according to this embodiment, tensile force is applied to the weak point 23 of the magnetic band 22 at high temperatures during the annealing process to cause the weak point 23 to rupture. Compared to the case where the weak point 23 is weakened by heat, the weak point 23 can be easily torn, and therefore the weak point 23 can be torn without creating any fragments. .

FIG. 5 shows a second embodiment of the present invention, which differs from the first embodiment described above in the following points. That is, the expansion mechanism 4
0 is constituted by a bag-shaped expansion container 42 that encloses an expansion body 41 such as air that expands when heated inside, and is disposed within the core window equivalent portion 24 of the wound core 21 .

Further, the expandable device 43 includes a pair of expandable devices 44 on both left and right sides.
．． 44, and the auxiliary 1 placed between these expansion molds 44 and 44. It consists of a wedge-shaped portion 46 having a convex portion 46a, and is disposed within the core window equivalent portion 24.

In this second embodiment as well, in order to sinter the wound core 21 in the same manner as in the first embodiment, when the assembled cores 21 are placed in an annealing furnace and heated, the expansion of the expansion body 41 causes each fat container to be heated. 42 expands, and the wedge shape 46 is pushed and moved in the direction of arrow A by the expanded fat container 42, and the wedge shape 46 pushes the expansion molds 44, 44 in the direction of arrow B, respectively, so that they correspond to the core window of the wound core 21. An expansion force acts on the portion 24 in a direction to expand it, and as a result, a tensile force acts on each weak point 23 of the magnetic band 22, and the weak point 23 is torn.

In the case of the second embodiment, in addition to producing the same effects as the first embodiment, there is an advantage that the amount of expansion of the fat expansion container 42 is large and the amount of expansion of the expandable device 44 can be increased.

2. In each of the above embodiments, air is used as an example of the expandable body 31, 41, but air may be used as long as it expands when heated, or other gases with relatively low melting points and fat expansion coefficients such as lead or zinc can be used. A large metal may also be used.

[Effects of the Invention] The present invention is as described above, and has the following effects.

In the method for manufacturing a wound core according to claim 1, the magnetic band is wound with weak points formed at each predetermined position in the winding direction, and after the bottom of the magnetic band is shaped into a predetermined shape, the weak points are torn. Therefore, in the method of manufacturing one-turn cut type wound core, tensile force is applied to the weak point of the magnetic band during the annealing process after forming the magnetic band to cause it to tear. It is possible to carry out the tearing in a very convenient manner without producing any harmful fragments, etc. (b), thereby preventing problems such as dielectric breakdown of built-in equipment such as transformers due to the fragments.

In the wound core tearing device according to claim 2, in order to tear the weak point of the magnetic band as described above, an expansion mechanism that expands when heated, and a portion of the magnetic band corresponding to the core window after molding are provided. This structure includes an expandable device which is disposed in the magnetic band and receives the expansion force from the expansion mechanism and applies an expansion force to the portion corresponding to the iron core window, thereby applying a tensile force to the weak point of the magnetic band. , the weak point can be ruptured reliably and efficiently.

[Brief explanation of drawings]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a plan view showing the main part in section, FIG. 2 is a perspective view, and FIG. 3 is an enlarged view of the expansion mechanism. The cutaway perspective view, FIG. 4, is a view corresponding to FIG. 1 for explaining the operation. Further, FIG. 5 is a diagram corresponding to FIG. 1 showing a second embodiment of the present invention. Fig. 6 is a vertical cross-sectional view showing the magnetic band being wound up, Fig. 7 is a longitudinal cross-sectional view of a conventional device for tearing the magnetic band, and Fig. 8 is an enlarged vertical cross-section of the weak point of the magnetic band. Figure 9 is a diagram showing the relationship between the survival rate of the weak point and the load required to tear the weak point.
Figure 10 is an enlarged vertical sectional view of the weak point that failed to tear, Figure 11 is a partial perspective view of another conventional device for tearing the magnetic band, and Figure 12 is the same device that tears the weak point. FIG. 3 is a partial plan view of the magnetic band showing the state after it has been removed. In the drawing, 21 is the wound core before annealing, 22 is the magnetic band, 23 is the weak point, 24 is the core window equivalent, 28 is the expansion mechanism, 30 is the cylinder, 31 is the expansion body, 32 is the expansion container, and 33 is the expansion. 34 is an expansion type, 35 is a wedge type, 40 is an expansion mechanism, 41 is an expansion body, 42 is an expansion container, 43 is an expansion type device, 44 is an expansion type, 45 is an auxiliary expansion type, 46 is a wedge type. shows.

Claims (2)

[Claims] 1. A method of manufacturing a one-turn cut type wound core by forming a weak point at each predetermined position in the winding direction and winding a magnetic strip, forming the magnetic strip into a predetermined shape, and then tearing the weak point. A method for manufacturing a wound iron core, characterized in that during an annealing step after winding and forming the magnetic band, a tensile force is applied to the weak point to cause it to tear. 2. An expansion mechanism that expands when heated, and an expansion mechanism that is disposed on a portion of the magnetic band after molding that corresponds to the core window, and that receives the expansion force from the expansion mechanism and applies an expansion force to the portion that corresponds to the core window, thereby expanding the magnetic band. A wound iron core tearing device comprising an expandable device that applies a tensile force to a weak point.