JPH04291907A - Induction electromagnetic device and sealed induction electromagnetic apparatus using it - Google Patents

Abstract

PURPOSE:To enhance an effective permeability and to reduce an iron loss while the feature of a filmlike magnetic material that its eddy-current loss is small is utilized at an induction electromagnetic device such as a transformer or a choke. CONSTITUTION:At an induction electromagnetic device 1, an inside core 2 and an outside core 6 which are formed by winding a film-like magnetic material M to be cylindrical shapes are provided, windings 4, 5 are mounted on the outer circumference of said inside core 2, said outside core 6 is situated at the outside of said windings 4, 5 so as to be arranged to be concentric with said inside core 2 and terminators 7 composed of a magnetic material are installed at end parts of both cores 2, 6 so as to fill a space between the end parts. The induction electromagnetic device 1 is covered with a heat-conductive heat-dissipating cover 35, and the inside of the cover 35 is filled with an electrically insulating cooling liquid 36. Thereby, a heat-dissipating effect is enhanced.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to induction electromagnetic devices such as transformers and chokes whose cores are formed by winding a film-like magnetic material into a cylindrical shape, and enclosed type induction electromagnetic devices that house the same in a heat dissipation cover. It is related to.

0002

2. Description of the Related Art Film-like magnetic materials have the advantage of having lower eddy current loss than bulk-like magnetic materials, and are therefore suitable for cores of high-frequency transformers and chokes. Therefore, as shown in FIG. 9, a core 51 made of such a film-like magnetic material wound into a cylindrical shape is used, and a winding 52 is wound around the core 51 in a toroidal shape to form a high-frequency transformer or choke. There is something like that.

0003

However, winding the winding 52 around the cylindrical core 51 in a toroidal manner is extremely inefficient. Therefore, in order to improve workability, it is conceivable to attach a spiral winding 52 concentrically with the core 51 on the outer peripheral surface of the cylindrically wound core 51, as shown in FIG. In this way, the cylindrical core 51 becomes open at both ends and does not constitute a closed magnetic path.
Magnetism leaks to the outside of the core, resulting in a lower effective magnetic permeability. Therefore, the present invention aims to improve the effective magnetic permeability while taking advantage of the above-mentioned features of the film-like magnetic material, thereby improving energy efficiency and facilitating manufacturing.

In order to achieve the above object, the induction electromagnetic device of the present invention has an inner core and an outer core formed by winding a film-like magnetic material into a cylindrical shape, and a winding wire is attached to the outer periphery of the inner core. and the outer core is located outside the winding and is arranged concentrically with the inner core, and terminators made of a magnetic material are located at both ends of the cores and in the space between the opposing ends. is provided. The terminator may be provided only at one end of both cores,
It is also possible to omit this. Further, in the enclosed induction electromagnetic device of the present invention, the induction electromagnetic device having the above-mentioned structure is covered with a heat conductive heat dissipation cover, and the heat dissipation cover is filled with an electrically insulating cooling liquid. The heat dissipation cover is preferably electrically conductive or ferromagnetic, or has both of these characteristics.

[0005]

[Operation] In the induction electromagnetic device of the present invention, an outer core made of a film-like magnetic material is arranged outside the winding, and a terminator made of a magnetic material is provided between both cores. Since the terminator becomes part of the path of the magnetism generated by energizing the winding, leakage of the magnetism to the outside is reduced, and the effective magnetic permeability, which is the magnetic permeability of the core as a whole, is improved. Further, since both the inner core and the outer core are cylindrical and are arranged concentrically, and the winding is attached to the outer periphery of the inner core, the magnetic flux passing through these cores is aligned in a fixed direction. On the other hand, since both cores are formed by winding a film-like magnetic material into a cylindrical shape, the direction of easy magnetization can be aligned in a constant direction over the entire region of the core. Therefore, with respect to the direction of magnetic flux passing through both cores, the direction of easy magnetization can be set to the optimum direction in the entire region of the core, thereby further improving the effective magnetic permeability and reducing iron loss (hysteresis loss). can be reduced.

Moreover, since the winding wire is attached to the outer periphery of the cylindrical inner core, the workability of this attachment is good. In addition,
Since the core is made by winding a film-like magnetic material, it is much easier to work with than the case where the core is made by stacking magnetic films cut to a predetermined size one by one. Furthermore, since this film-like magnetic material has less mechanical distortion than a punched plate material, heat treatment after processing the core is not necessary. Furthermore, since both cores are made of film-like magnetic material, they still have the advantage of conventional film-like magnetic materials, such as low loss due to eddy currents.

[0007] The terminator may be provided only at one end of the core, or may be omitted. Even if the terminator is omitted, the effective magnetic permeability of the core is improved compared to the example of FIG. 10 because the outer core is part of the magnetic path. Furthermore, in the enclosed induction electromagnetic device of the present invention, the induction electromagnetic device having the above structure is covered with a heat conductive heat dissipation cover, and the heat dissipation cover is filled with an electrically insulating cooling liquid, so that the induction electromagnetic device can dissipate heat. is carried out effectively. If the heat dissipation cover is made conductive, high frequency magnetism from the induction electromagnetic device can be prevented from leaking to the outside and adversely affecting surrounding equipment. Moreover, if the heat dissipation cover is made of ferromagnetic material, it is possible to prevent a direct current magnetic field from the outside from having an adverse effect on the induction electromagnetic device inside.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 shows a high frequency transformer 1, which is a type of induction electromagnetic device, in which a primary winding 4 and a secondary winding 5 are attached to the outer periphery of an inner core 2 with an insulating layer 3 in between. Outside the windings 4 and 5, an outer core 6 is arranged concentrically with the inner core 2.

Both cores 2 and 6 are made by winding a film-like magnetic material M into a cylindrical shape, as shown in FIG. As this magnetic material M, an ultra-thin (e.g. 3 μm) amorphous film based on iron or cobalt, or a thin sheet of permalloy, iron, silicon steel plate, etc. with an insulating film formed on one or both sides is used. be done. This magnetic material M is given magnetic anisotropy, and its easy magnetization direction A is aligned in a certain direction. Techniques for aligning the easy magnetization direction A in a certain direction have been known for a long time. For example, in the case of an amorphous film, by heat-treating it in a magnetic field, the easy magnetization direction A of the film is aligned in a certain direction. In the case of thin sheets such as permalloy, iron, and silicon steel sheets, when the sheet material is rolled, the direction of easy magnetization is aligned with the rolling direction, so the sheet made from this material is By appropriately setting the cutting direction, the easy magnetization direction A of the sheet can be aligned in a desired direction.

This easy magnetization direction A is, as described later,
When cores 2 and 6 are made by winding magnetic material M, cores 2,
It is desirable to set the angle so that it has an optimum angle with respect to the direction of the magnetic flux passing through 6. Further, both the cores 2 and 6 are set to have almost the same volume so that the magnetic flux density is the same, and therefore the inner core 2, which has a smaller radius, is wound so that it is thicker than the outer core 6. ing.

Both upper and lower ends 21, 2 of the cores 2, 6
2, 61, and 62 are provided with terminators 7, 7, thereby filling the gap between both cores 2, 6. These terminators 7, 7 are made of magnetic material such as ferrite, sendust, permalloy,
It is fixed using an adhesive between one end 21 and 61 and the other end 22 and 62 of both cores 2 and 6, which face each other, and is positioned so as to fill the space between these ends. The terminator 7 has a flange 7a, and this flange 7a is used for the core 2.
, 6 are pressed against the end surfaces 8 of the two.

The terminator 7 has a donut shape as shown in FIG. 3, and is provided with a large number of axial grooves 10 and through holes 11 to allow a cooling fluid such as air or oil to flow therethrough. These grooves 10 and through holes 11 are
It is also used as an extraction hole for the windings 4 and 5. Note that if the magnetic material used to form the terminator 7 has a lower magnetic permeability than the material of the cores 2 and 6, the volume of the terminator 7 should be increased to prevent an increase in magnetic resistance in the terminator 7, thereby reducing its magnetic path area. In other words, it is preferable to increase the cross-sectional area when taken through a circle concentric with the cores 2 and 6.

Furthermore, as shown in FIG. 4, the easy magnetization direction A of the magnetic material M shown in FIG.
It is possible to set the optimum angle with respect to the direction No. 3. The reason is as follows. That is, since both the inner core 2 and the outer core 6 are cylindrical and are arranged concentrically, and the windings 4 and 5 are attached to the outer periphery of the inner core 2 and the outer core 6, the magnetic flux 13 passing through these cores is directed in a fixed direction. Align. On the other hand, since both cores 2 and 6 are formed by winding a film-like magnetic material M into a cylindrical shape, the direction of easy magnetization A thereof can be aligned in a constant direction over the entire area of the cores 2 and 6. Therefore, the easy magnetization direction A can be set at any angle in the entire area of the cores 2 and 6 with respect to the direction of the magnetic flux 13 passing through both the cores 2 and 6.

The optimum angle of the easy magnetization direction A with respect to the magnetic flux 13 differs depending on the frequency of the current flowing through the windings 4 and 5. For example, when the magnetic material M is a cobalt-based amorphous film, as shown in FIG. are almost parallel, and in a high frequency region of 1 MHz or higher, as shown in FIG. 4(b), the directions are 90 degrees, that is, both directions are perpendicular to each other. The reason why the optimum angles are different in this way is that the magnetization of the cores 2 and 6 due to the alternating magnetic field occurs due to domain wall movement in the low frequency range, and occurs due to rotational magnetization in the high frequency range. The frequency band in which this domain wall movement occurs and the frequency band in which rotational magnetization occurs differ depending on the material of the core.

In the above configuration, the magnetic flux 13 generated by energizing the primary winding 4 passes through a magnetic path formed by the inner core 2, terminator 7, and outer core 6 made of magnetic material. Therefore, the overall magnetic permeability,
In other words, the effective magnetic permeability is improved.

Furthermore, since the easy magnetization direction A of the magnetic material M shown in FIG. 2 is set at an arbitrary angle with respect to the direction of the magnetic flux 13 passing through the cores 2 and 6, as described above, Effective magnetic permeability can be improved and iron loss can be minimized.

Furthermore, since the winding wire is attached to the outer periphery of the cylindrical inner core, the workability of this attachment is good. In addition,
Since the core is made by winding a film-like magnetic material, it is much easier to work with than the case where the core is made by stacking magnetic films cut to a predetermined size one by one. Furthermore, since this film-like magnetic material has less mechanical distortion than a punched plate material, it does not require heat treatment after processing the core, making it easier to manufacture. Furthermore, the inner core 2 in FIG.
Since both the outer core 6 and the outer core 6 are wound with a film-like magnetic material M having an insulating film on the surface, eddy current loss is small.

Further, since cooling fluid, such as air, enters and exits the space 12 between the cores 2 and 6 through the large number of flow grooves 10 and through holes 11 provided in the terminator 7, the winding 4, 5 and the cores 2, 6 are effectively radiated. Note that if the terminator 7 is made of the same material as the film-like magnetic material M or compressed powder made of high-frequency ferrite, etc., eddy current loss will increase and the damage between the terminator 7 and the cores 2 and 6 will increase. There is a concern that magnetic resistance will increase on the connection surface. However, if the magnetic passage area of the terminator 7 is set larger than the passage area (cross-sectional area) of the cores 2 and 6, the terminator 7
In addition to lowering the magnetic flux density within, the increased contact area also reduces magnetic resistance, so that energy loss due to the terminator 7 can be sufficiently suppressed.

Next, a second embodiment of the present invention will be explained. In FIG. 5, the outer periphery of the terminator 7 and the outer core 6
A gap 25 is provided between them. Thereby, the magnetic resistance is increased and a large current transformer 1 is obtained. Note that since the windings 4 and 5 are wound around an electrically insulating bobbin 20 and attached to the inner core 2, the insulating film 3 in FIG. 1 is omitted.

Here, as shown in FIG. 6, the gap 26
can also be provided between the inner peripheral part of the terminator 7 and the inner core 2. However, when doing this, the inner core 2
Gap 2 with large magnetic resistance between and terminator 7
6 exists, a part of the magnetic flux 13 generated by the current in the primary winding 4 does not pass through the gap 26,
Enter terminator 7 diagonally as shown by arrow D. As a result, less magnetic flux passes through the secondary winding 5, so
The coupling coefficient between the primary winding 4 and the secondary winding 5 becomes smaller. Therefore, it is preferable to provide the gap on the outer peripheral side of the terminator 7, as in the second embodiment shown in FIG.

FIG. 7 shows an encapsulated induction electromagnetic device 31 according to a third embodiment of the present invention. This enclosed induction electromagnetic device 3
1 houses the transformer 1 having the structure shown in FIG. 1 above. The terminator 7 on the lower side of the transformer 1 has a sealing plate 32 made of metal or resin on its lower surface.
is attached, while the terminal 3 connected to the windings 4, 5
3 passes through the through hole 11 of the terminator 7, and further,
It passes through an insertion hole 34 provided in the sealing plate 32 and is drawn out to the outside. The transformer 1 is covered with a heat transfer cover 35 made of a ferromagnetic material with excellent heat conductivity and conductivity such as permalloy, and the lower end of the heat transfer cover 35 is
It is fixed to the lower terminator 7 and the sealing plate 32. Further, the heat transfer cover 35 is filled with an electrically insulating cooling liquid 36, such as a mixed oil containing alkylbenzene as a main component.

In this third embodiment, mainly the winding 4
, 5, the coolant 36 is heated by the heat dissipated from the terminator 7 and the through hole 1 by natural convection.
1 and flows as indicated by the arrow. Therefore, in addition to cooling the cores 2 and 6, the windings 4 and 5 located in the space 12 between the cores 2 and 6 are also cooled, and then the heat is radiated through the heat transfer cover 35. This effectively radiates heat from the transformer 1, resulting in a compact and large-capacity transformer. Furthermore, since the heat transfer cover 35 is conductive, it is possible to prevent high frequency magnetism from the transformer 1 from leaking to the outside and adversely affecting surrounding equipment. Further, since the heat dissipation cover 35 is ferromagnetic, it can prevent a direct current magnetic field from the outside from having an adverse effect on the internal transformer 1, and is effective in preventing noise in the transformer 1.

Note that if cooling fins are attached to the outer periphery of the heat transfer cover 35, the heat dissipation ability will be improved. Furthermore, if there is no need to consider the adverse effects of the magnetic field leaking from the transformer 1 to the outside, the heat dissipation cover 35 may not be electrically conductive. On the other hand, if there is no need to consider the adverse effects of external magnetic fields on the transformer 1, the heat transfer cover 35 may not be ferromagnetic, and in this case, the heat transfer cover 35 may be made of a material with excellent heat transfer and electrical conductivity. For example, it can be made of copper or aluminum. If there is no need to consider the magnetic field leaking from the transformer 1 to the outside or the magnetic field entering the transformer 1 from the outside, the heat transfer cover 35 may be made of a material that is neither conductive nor ferromagnetic, such as resin. It is. Further, when the power of the transformer 1 is sufficiently small, in which heat generation is small and the heat is sufficiently dissipated by natural air cooling, a structure as shown in FIGS. 1 and 5 without the heat transfer cover 35 may be used.

In the first to third embodiments described above, the terminator 7 is connected to both ends 21, 22 of the cores 2, 6,
Although it is provided at 61 and 62, it may be provided only at one end portion 21 and 61. Further, as in the fourth embodiment shown in FIG. 8, the terminator may be omitted. Even in this case, magnetic leakage is reduced due to the presence of the outer core 6, so the effective magnetic permeability is improved accordingly compared to the example of FIG. here,
The wide space between the cores 2 and 6 acts as a kind of gap. It goes without saying that the present invention can be applied not only to the transformer 1 but also to chokes.

[0025]

[Effects of the Invention] In the induction electromagnetic device of the present invention, in addition to the inner core, the outer core and the terminator become part of the magnetic path generated by energizing the winding, so that the magnetic field is not transmitted to the outside. Leakage is reduced and the effective magnetic permeability, which is the magnetic permeability of the entire core, is improved. As a result, energy loss in the induction electromagnetic device is reduced and efficiency is improved. In addition, the direction of easy magnetization of the core can be set to the optimum direction in the entire region of the core with respect to the direction of magnetic flux passing through the inner and outer cores, thereby reducing iron loss (hysteresis loss). can. Such improvement in effective magnetic permeability and reduction in iron loss reduces energy loss in the induction electromagnetic device and improves efficiency.

Moreover, since the winding wire is attached to the outer periphery of the cylindrical inner core, the workability of this attachment is good. In addition,
Since the core is made by winding a film-like magnetic material, it is much easier to work with than the case where the core is made by stacking magnetic films cut to a predetermined size one by one. In addition, the thinner the film-like magnetic material is, the less mechanical distortion there is compared to a punched plate material, so there is no need for heat treatment after processing the core, which also improves workability. Furthermore, since both cores are made of film-like magnetic material, they still have the advantage of conventional film-like magnetic materials, such as low loss due to eddy currents.

Even if the terminator is provided only at one end of the core or is omitted, at least the outer core becomes a part of the magnetic path, so the effective magnetic permeability of the core is improved accordingly.

[0028] Furthermore, the enclosed induction electromagnetic device of the present invention includes:
Since the induction electromagnetic device having the above structure is covered with a heat conductive heat dissipation cover and the heat dissipation cover is filled with an electrically insulating coolant, heat of the induction electromagnetic device is effectively radiated. If the heat dissipation cover is made conductive, high frequency magnetism from the induction electromagnetic device can be prevented from leaking to the outside and adversely affecting surrounding equipment. Furthermore, if the heat dissipation cover is made of ferromagnetic material, it is possible to prevent a direct current magnetic field from the outside from having an adverse effect on the internal induction electromagnetic device, which is effective in preventing noise in the induction electromagnetic device.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a transformer according to a first embodiment of the invention.

FIG. 2 is a perspective view showing a film-like magnetic material forming the core of the transformer in FIG. 1;

FIG. 3 is a perspective view showing an upper terminator of the transformer in FIG. 1;

4 is a perspective view showing the relationship between the direction of easy magnetization and the direction of magnetic flux in the core of the transformer shown in FIG. 1. FIG.

FIG. 5 is a longitudinal sectional view showing a transformer according to a second embodiment of the invention.

FIG. 6 is a vertical cross-sectional view of essential parts showing a modification of the transformer shown in FIG. 6;

FIG. 7 is a longitudinal sectional view showing an enclosed transformer according to a third embodiment of the invention.

FIG. 8 is a longitudinal sectional view showing a transformer according to a fourth embodiment of the invention.

FIG. 9 is a perspective view showing a conventional transformer using a core formed by winding a film-like magnetic material.

FIG. 10 is a perspective view showing one possible example of a transformer using a core formed by winding a film-like magnetic material.

[Explanation of symbols]

1...Transformer (induction electromagnetic device), 2...Inner core, 4...Primary winding, 5...Secondary winding, 6...Outer core, 7...Terminator, 21, 22...Both ends of inner core, 31...Enclosed type Induction electromagnetic device, 35... Heat radiation cover, 36... Coolant, 61, 62
...both ends of the outer core, A...direction of easy magnetization, M...film-like magnetic material.

Claims (5)

[Claims] 1. An inner core 2 and an outer core 6 each formed by winding a film-like magnetic material M into a cylindrical shape, windings 4 and 5 are attached to the outer periphery of the inner core 2, and the outer core 6 is A terminator 7 made of a magnetic material is provided at both ends 21, 22, 61, 62 of the cores 2, 6, and is located outside the windings 4, 5 and concentrically with the inner core 2. An induction electromagnetic device characterized in that it is located in a space between its opposing ends 21-61 and 22-62. 2. An inner core 2 and an outer core 6 each formed by winding a film-like magnetic material M into a cylindrical shape, windings 4 and 5 are attached to the outer periphery of the inner core 2, and the outer core 6 is A terminator 7 made of a magnetic material is disposed outside the windings 4 and 5 and concentrically with the inner core 2, and is provided at one end portions 21 and 61 (22 and 62) of both the cores 2 and 6. and its opposite ends 21-61 (22-62
) An induction electromagnetic device characterized by being located in the space between 3. It has an inner core 2 and an outer core 6 made of a film-like magnetic material M wound into a cylindrical shape, windings 4 and 5 are attached to the outer periphery of the inner core 2, and the outer core 6 is An induction electromagnetic device characterized in that it is arranged outside the windings 4 and 5 and concentrically with the inner core 2. 4. The induction electromagnetic device according to claim 1, wherein the induction electromagnetic device is covered with a heat conductive heat dissipation cover, and the heat dissipation cover is filled with an electrically insulating cooling liquid. Enclosed type induction electromagnetic device. 5. The enclosed induction electromagnetic device according to claim 4, wherein the heat dissipation cover has at least one of conductivity and ferromagnetism.