JPH01246808A - Electromagnetic device - Google Patents

Abstract

PURPOSE:To increase the variable amount of inductance by a method wherein the title electromagnetic device is constituted in such a manner that the protruding part of the external magnetic path is positioned outside the protruding part of the internal magnetic path of a pot core, and the recessed part of the external magnetic path is positioned outside the recessed part of the inner magnetic path. CONSTITUTION:Pot cores 11 and 12 are composed of inner magnetic paths 13 and 15, which are through inside of a bobbin 10, and the external magnetic paths 14 and 16 which are fitted externally. The butting surfaces 17, 18, 19 and 20 of the inner magnetic paths 13 and 15 and outer magnetic paths 14 and 16 are divided into two parts in circumferential direction of protruding parts 21, 23, 25 and 27 and recessed parts 22, 24, 26 and 28, and the protruding parts 21 and 25, and 23 and 27 and the recessed parts 22 and 26, and 24 and 28 are opposingly positioned with each other. The more the distance between magnetic materials becomes smaller, the more magnetic reluctance becomes low, and also the more the opposing area becomes wider, the more magnetic resistance becomes lower. As a result, in the state of theta=0 (protruding parts 21 and 25, and 23 and 27 are opposing with each other, the magnetic resistance becomes larger in the order of theta=90 deg. and theta=180, and inductance becomes lower. At the same time, the variable amount of the inductance increases when compared with the device manufactured in the past in which recessed and protruding parts are formed on the inner magnetic path only and also the device in which the recessed and protruding parts of the inner and the outer magnetic paths are not opposingly positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to electromagnetic devices such as high frequency transformers and chokes.

[Conventional technology]

2. Description of the Related Art Conventionally, there are electromagnetic devices such as high frequency transformers and chokes used at frequencies of 10 KHz or higher, such as telephones, electronic circuits, switching power supplies, inverter lighting circuits, and the like. The electromagnetic device consists of a winding and two cores surrounding the winding. The core used is a cylindrical pot core, which has been used for a long time because the coil has high frequency characteristics and low leakage magnetic flux, but there is a strong need for coil inductance management from a circuit standpoint. For example, when changing the resonant frequency in an LC series resonant circuit, a variable inductance must be used if there is no variable capacitor with high voltage resistance. Also, when a large amount of non-standard inductance occurs due to manufacturing variations in the core and windings,
This will need to be adjusted.

Therefore, there are variable inductance elements using a cylindrical pot core as shown in FIGS. 12 to 14. In the figure, 50 is a bobbin, and 51 and 52 are a pair of ferrite cores. A mating surface 55.5 of the inner magnetic paths 53, 54 passing through the bobbin 50 of each core 51.52
6 is divided into two parts: a convex portion 57°58 and a concave portion 59,60. The upper and lower cores 51.52 are rotated relatively around the vertical axis to change the magnetic resistance of the mating surfaces 55.56,
Change the inductance. Changes in the magnetic flux of the mating surfaces 55, 56 due to rotation will be explained using FIGS. 15 to 18. The states shown in FIGS. 15 and 16 are the convex portions 57 and 58 of the mating surfaces 55 and 56 and the concave portions 59.
, 60 face each other (rotation angle θ-〇°). In addition, the states shown in FIGS. 17 and 18 are as follows:
Compared to the state shown in FIG. 15, the cores 51 and 52 are relatively rotated by 90 degrees (θ=90 degrees), and the overlapping area of the convex portions 57 and 58 is half. The magnetic resistance decreases as the distance between the magnetic bodies becomes smaller and as the opposing area increases, so the magnetic resistance is smaller and the inductance is higher in the state shown in FIG. 15 than in the state shown in FIG. 17.

[Problem to be solved by the invention]

As mentioned above, it is desirable to have a variable inductance element that utilizes the rotation of the cores 51, 52, but the inner magnetic path 53. ．． Convex portions 57° 58 and concave portions 59 only on 54
, 60, the amount of inductance variation is small, and particularly in an electromagnetic device having a gear rough between the upper and lower cores 51 and 52, there is a problem that a predetermined amount of variation cannot be obtained.

Therefore, as shown in FIGS. 19 to 21, the mating surface 69.7 of the external passage 67.68 of the pot core 65.66 is
0 has also proposed an electromagnetic device in which convex portions 7], 72 and concave portions 73 and 74 are formed. Convex portion 71 of outer magnetic path 67,68
．． 72 is located outside the recesses 79, 80 of the inner magnetic path 75.76, and the recesses 73, 74 of the outer magnetic path 67.68 are located outside the convex portions 77.78 of the inner magnetic path 15.76. ing.

FIGS. 22 to 25 show the pot core 65.degree. 66 rotated relative to each other about the vertical axis to change the magnetic resistance. The states shown in FIGS. 22 and 23 are the convex portions 71, 72, 77, . 78 and recesses 73 and 74
, 79.80 face each other (rotation angle θ=0°), magnetic resistance is minimized, and inductance is maximized. Further, in the states shown in FIGS. 24 and 25, the pot cores 65 and 66 are relatively rotated by 180 degrees (θ-180'), and the magnetic resistance is maximum and the inductance is minimum.

However, the amount of change in inductance is still small.

Therefore, it is an object of the present invention to provide an electromagnetic device with increased variable inductance.

[Means to solve the problem]

The electromagnetic device of this invention includes a bobbin wound with electric wire,
A pair of cylindrical pot cores are attached to the bobbin from both ends, and each of the mating surfaces of the inner magnetic path and the outer magnetic path is lined up in the circumferential direction and has concave and convex portions formed thereon. The convex portion of the outer magnetic path is located outside the convex portion, and the recessed portion of the outer magnetic path is located outside the recessed portion of the inner magnetic path.

(Function) According to the electromagnetic device of the present invention, the uneven portions are formed on the mating surfaces of the inner magnetic path and the outer magnetic path of the pair of pot cores so as to be lined up in the circumferential direction. Furthermore, the convex portion of the outer magnetic path is located outside the convex portion of the inner magnetic path, and the concave portion of the outer magnetic path is located outside the concave portion of the inner magnetic path.

Therefore, the amount of variation in inductance increases compared to a conventional structure in which uneven portions are formed only in the inner magnetic path, or in which the uneven portions in the inner magnetic path and outer magnetic path do not correspond to each other.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 to 9.

In FIG. 1, 10 is a bobbin around which an electric wire (not shown) is wound. Further, 11 and 12 are ferrite pot cores formed into a cylindrical shape.

Both the pot core 11 (see FIG. 2) and the pot core 12 are composed of inner magnetic paths 13 and 15 passing through the bobbin 10 and outer magnetic paths 14 and 16 that are fitted onto the bobbin 10. The mating surfaces 17.1B, 19° 20 of the inner magnetic paths 13, 15 and the outer magnetic paths 14, 16 are formed by convex portions 21, 19, 20, respectively.
It is divided into two in the circumferential direction into recesses 23, 25 and 27 and recesses 22, 24 and 26 and 28. Furthermore, the convex portions 21, 23 of the inner magnetic paths 13, 15 and the convex portions 25, 27 of the outer magnetic paths 14, 16 are located on the same side, and the concave portions 22, 24 and the concave portions 26, 28 are also located on the same side. ing.

Next, using FIGS. 4 to 8, pot core 11.
The change in the magnetic flux of the mating surfaces 17.18° and 19.20° due to the rotation of 12 will be explained. 4 and 5 show a state in which the convex portions 21.25 of the pot core 11 and the convex portions 23.27 of the pound core 12 are completely facing each other (rotation angle θ-〇).

), FIG. 6 shows the IJ state rotated by 90 degrees from the state shown in FIG. 4 (θ-90''), and FIGS. 2
8 are completely facing each other (θ-1
80°). Magnetic resistance decreases as the distance between magnetic bodies decreases and as the opposing area increases, so when θ=0'', θ
It increases in the order of -90' state and θ=180@ state. Also, inductance increases in the opposite order to magnetic resistance.

According to the electromagnetic device configured in this way, the pot core 1
Convex portions 21, 23,
Since the concave portions 22, 24° and 26.28 are formed, the amount of change in inductance is larger than in the conventional example in which concave and convex portions are formed only in the inner magnetic path. Furthermore, compared to an electromagnetic device in which the concave and convex portions of the inner magnetic path and the outer magnetic path are located oppositely, as shown in FIG. 19, the amount of change in inductance is large (i.e. As shown in Figures 1 to 3, if the horizontal axis represents the relative rotation angle θ of the pot core, and the vertical axis represents the inductance change rate ΔL/L, the inner magnetic paths 13 and 15 and the outer magnetic paths as shown in Figures 1 to 3 are Convex portions 21, 2 of magnetic path 14.16
3, 25.27 and recesses 22, 24, 26.2
8 are located on the same side, as shown by the solid line A, and the convex portions 77, 78 and concave portions 79, 80 of the internal magnetic path 75° 76 as shown in FIGS. 19 to 21 are located on the outside. Concave portions 73, 74 and convex portions 71. of the magnetic paths 67, 68.
An electromagnetic device compatible with 72 is shown by a broken line B. As you can see from this graph, the internal magnetic IPI is 13.15.
The convex portions 21, 23 and concave portions 22, 24 of the outer magnetic path 14.
The amount of change in inductance becomes larger when the convex portions 25 and 27 and the concave portions 26 and 2B of No. 16 are made to correspond to each other. From the above, it is possible to realize a variable inductance element whose inductance can be varied over a wide range, and it is possible to absorb variations in components caused by inductance manufacturing. Furthermore, variations in other components (for example, capacitors, transistors, etc.) connected to the inductance element can also be corrected by varying the inductance. Furthermore, it is possible to manage a wide range of frequency characteristics in the LC resonant circuit.

Other embodiments of the invention are shown in FIGS. 10 and 11. In the pot core 30 of the example shown in FIG. 10, the mating surface 33 of the inner magnetic path 31 is divided into four to form convex portions 34 and recessed portions 35 alternately, and the mating surface 36 of the outer EfHIR 39 is also divided into four parts.
The convex portions 37 and concave portions 38 are formed alternately by dividing the convex portion 37 of the outer magnetic path 39 to the outside of the convex portion 34 of the inner magnetic path 31, and the convex portion 37 of the outer magnetic path 39 is located outside the convex portion 34 of the inner magnetic path 31. A recess 38 of the outer magnetic path 39 is located on the outside.

Further, in the pot core 40 of the example shown in FIG. 11, the mating surfaces of the inner magnetic path 41 and the outer magnetic path 44 are each divided into six parts, and convex parts 42.45 and four parts 43.46 are formed alternately. The convex portions 42, 45 and the concave portions 43, 46 correspond to each other.

〔Effect of the invention〕

According to the electromagnetic device of the present invention, the uneven portions are formed on the mating surfaces of the inner magnetic path and the outer magnetic path of the pair of pot cores, respectively, in line with the circumferential direction. Moreover, the convex portion of the outer magnetic path is located outside the convex portion of the inner (n path), and the concave portion of the outer magnetic path is located outside the concave portion of the inner magnetic path.

Therefore, the effect of increasing the variable amount of inductance is obtained compared to the conventional case in which unevenness is formed only in the inner magnetic path, or in which the unevenness in the inner magnetic path and outer magnetic path do not correspond to each other. It will be done.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of an embodiment of the present invention, Fig. 2 is a perspective view of its pond core, Fig. 3 is a sectional view of its pot core, and Figs. 4 to 8 show the pot cores relative to each other. FIG. 9 is a graph showing the relationship between the rotation angle of the pot core and the rate of change in inductance. FIG. 10 is a perspective view of a pot core according to another embodiment of the present invention. FIG. FIG. 12 is a perspective view of a conventional example, and FIG.
Figure 14 is a perspective view of the pot core, Figure 14 is a sectional view of the pot core, Figures 15 to 18 are illustrations of the pot cores rotated relative to each other, and Figure 19 is an exploded perspective view of the proposed example. , FIG. 20 is a perspective view of the pot core, FIG. 21 is a cross-sectional view of the bond core, and FIGS. 22 to 25 are illustrations of the pound cores rotated relative to each other. 10...Bobbin, 11.12...Pot core, 13
゜15...Inner magnetic path, 14.16...Outer magnetic path, 17,
18°19.20... mating surface, 21, 23, 25.
27... Convex portion, 22, 24, 26. 28... Concave portion Patent applicant Matsushita Electric Works Co., Ltd. Fig. 1 Fig. 6 Fig. 7 Fig. 80 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 14 Figure 15 Figure 19 Figure 20 Figure 21 Figure 22 Figure 24 Figure 23 Figure 25

Claims (1)

[Claims] It is equipped with a bobbin around which electric wire is wound, and a pair of cylindrical pot cores that are attached to the bobbin from both ends and have concavities and convexities aligned in the circumferential direction on the mating surfaces of the inner magnetic path and the outer magnetic path, respectively. In the electromagnetic device, a convex portion of the outer magnetic path is located outside a convex portion of the inner magnetic path, and a concave portion of the outer magnetic path is located outside a concave portion of the internal magnetic path. Features an electromagnetic device.