JPH04302409A - Plane inductance element - Google Patents

Abstract

PURPOSE:To increase withstand voltage of a plane inductance element and reliability to a temperature thereof and to make inductance changeable. CONSTITUTION:A plurality of plane-like coils 14a, 14b are laminated. The coils 14a, 14b are connected mutually to allow a current flowing in the coils flow in the same direction and a wiring block set is thereby constituted. A plurality of wiring block sets 1a to 2c are laminated with insulating films 13a, 13b, respectively in between.

Description

[Detailed description of the invention]

[Object of the invention]

0002

[Industrial Application Field] The present invention is applicable to power supplies, inverters,
The present invention relates to a small and thin planar inductance element suitable as an inductance element for a transmitter and the like, and particularly to a planar inductance element that is an improved planar inductance element.

0003

2. Description of the Related Art Conventional inductance elements include copper wire wound into a coil, but since the inductance is proportional to the square of the diameter and the number of turns, there is a limit to miniaturization and thinning.

[0004] Therefore, in recent years, planar coils such as inductance elements and sliced coils in which a conductor is printed in a coiled or spiral shape on a printed circuit board have been proposed.

[0005] A sliced coil is made by superimposing an insulator on a conductive thin strip having a desired width, first winding it in a spiral shape to form a spiral cylinder, and then rolling this spiral cylinder in the axial direction as required. Constructed by slicing lengths.

FIG. 7 shows a plane of an example of such a planar coil 1, in which the conductor 2 is centered on one plane.
It is wrapped in a spiral around a.

Further, this planar coil 1 has conventionally been assembled into a planar inductance element, a planar transformer 3 shown in FIG. 8, and the like.

This planar transformer 3 has, for example, a pair of upper and lower planar coils 1A and 1B stacked concentrically in the vertical direction, and the upper and lower surfaces of this stacked body are made of amorphous alloy, ferrite, etc.
It is sandwiched between a pair of upper and lower magnetic bodies 4a and 4b in the figure, such as permalloy, and is configured such that one of the pair of planar coils 1A and 1B is on the low voltage side and the other 1B is on the high voltage side.

As a method of forming the high-voltage side planar coil 1B in a spiral shape using a single coated conductor coated with an insulating film, a planar coil 1B1 shown in FIGS. 9 and 10 is used.
, 1B2.

FIG. 9 shows a longitudinal section of the planar coil 1B1 on one side from the spiral central axis Oa, with a portion omitted.
This planar coil 1B1 first includes a coated conducting wire 5a,
It is tightly wound spirally around the spiral center axis Oa, for example, from the top to the bottom in the figure at the spiral center.

[0011] Next, when it has been wound to the lower end, it moves to the next outer periphery and this time it is spirally and tightly wound from the bottom to the top, and after reaching the upper end, it continues to the outside. Then, it is again spirally and densely wound from top to bottom, and by repeating this process, a spiral planar coil 1B1 having the required diameter and thickness is formed.

However, in this planar coil 1B1, the potential difference between the potential Va at the winding start end a and the potential Vb at the next adjacent part b on the outer circumferential side is determined by the current flow between parts a and b. Since the direction is opposite as shown by the arrow in the figure,
The voltage drop increases correspondingly to the voltage drop from section a to section b of the covered conductor 5a, and since a high voltage is applied to the high voltage side winding, the insulation of the covered conductor 5a alone is insufficient.

Therefore, as shown in FIG. 11, a method can be considered to increase the dielectric strength of the coil 1B1 by wrapping an insulating tape 6 in the radial direction of the planar coil 1B1 at a predetermined pitch.

However, in this method, the planar coil 1B1
Since the overall thickness is very thin, for example, on the order of several mm or less, it is extremely difficult to wrap the insulating tape 6 around this planar coil 1B1 in terms of manufacturing.

On the other hand, a planar coil 1B2 shown in FIG.
For example, at the lower end in the figure, one coated conductor 5b is wound in a plane spiral shape from the outer circumference toward the center of the spiral, and after reaching the center, the wire is moved to the next upper stage, and this time the spiral winds. It is wound in a planar spiral shape from the center to the outer circumferential side, and by repeating this winding, multiple stages are formed in the vertical direction.

However, even in this planar coil 1B2, for example, the potential Vc at the winding start end c of the covered conductor 5b,
The potential difference with the potential Vd of the portion d immediately above and adjacent to this is also because the current directions in both portions c and d are opposite, so both portions c,
d increases correspondingly to the voltage drop between d and moreover, since a high voltage is applied to the high-voltage side winding, the sheath insulation of the sheathed conductor 5b alone becomes insufficient.

[0017] Such a high potential difference is caused by e,
This also occurs in the f section, and since the central part generally has weak ventilation and poor heat dissipation, the temperature rise causes a drop in the dielectric strength of the covered conductor 5b, as shown in FIG.

[0018]

[Problems to be Solved by the Invention] As mentioned above, in the conventional planar coils 1B1 and 1B2, the covered conductor 5a
, 5b adjacent parts a and b in the radial direction or thickness direction,
The potential difference between c and d and between e and f is high, and the withstand voltage is insufficient. For this reason, the margin of withstand voltage against temperature rise is small, resulting in low reliability against temperature rise.

The present invention has been made in consideration of these circumstances, and its object is to provide a planar inductance element that not only has a high withstand voltage but also has high reliability against temperature rises. [Structure of the invention]

[0020]

[Means for Solving the Problems] In order to solve the above problems, the present invention is constructed as follows.

The invention according to claim 1 of the present application (referred to as the first invention) is a structure in which a plurality of planar windings are laminated, and the direction of current flowing through these windings is the same. The present invention is characterized in that a plurality of sets of the winding blocks are formed by stacking each block with an insulator interposed therebetween.

[0022] Furthermore, the invention according to claim 2 of the present application (second
invention), a plurality of planar windings are stacked, these windings are formed so that the direction of current flowing through these windings is the same, and at least one of these planar windings is moved. It is characterized by being freely configured.

[0023]

[Operation] <First invention> Since the current flow direction is the same between multiple planar windings that are adjacent to each other in the stacking direction, the potential difference between adjacent portions of each planar winding in the stacking direction is very small. .

Moreover, since an insulator is interposed between the winding blocks made up of a plurality of planar windings, the withstand voltage is further increased. In addition, since it has a high withstand voltage, there is a margin in the withstand voltage, and therefore, even if the dielectric withstand voltage decreases due to a temperature rise due to heat generated by energization of the planar winding, a sufficient withstand voltage can be maintained.

<Second invention> In the first invention, by moving at least one of the plurality of laminated planar windings and controlling the opposing areas of these windings, the distance between these planar windings is Inductance can be controlled by appropriately varying mutual inductance and line capacitance.

[0026]

[Embodiments] Hereinafter, embodiments of the first and second inventions of the present application will be described.

FIG. 1 is a longitudinal sectional view of an embodiment of the first invention of the present application, and in the figure, a planar inductance element 11
For example, three sets of planar winding blocks 12a, 12b, 1
2c are laminated concentrically in the vertical direction in the figure with the central axis Ob as the center, and electrical insulating films 13a and 13b are interposed between the planar winding blocks 12a to 12c, respectively.

As shown in FIG. 2, each of the planar winding blocks 12a to 12c includes, for example, two stages of upper and lower planar coils 14a.
, 14b are laminated concentrically around the central axis Ob, and their outermost peripheries are vertically connected by a connecting line 15c.

For this purpose, two stages of upper and lower planar coils 14
The direction of current flow in a and 14b becomes the same as shown by the arrows in the figure, the potential difference between mutually adjacent parts is reduced, and the withstand voltage of the insulating film of the covered conductor becomes sufficient. moreover,
Insulating films 13a and 13b are interposed between each of the planar winding blocks 12a to 12c, so that between each of the planar coils 14a and 14b, the planar winding block 1
The breakdown voltage between 2a and 12c becomes sufficiently high.

Therefore, even when these are used as the high-voltage side winding of a planar transformer and a high voltage is applied to them, sufficient withstand voltage can be obtained.

FIG. 3 is a plan view of an embodiment of the second invention of the present application, and this planar inductance element 15 has, as described above, a rectangular spiral-shaped planar structure with the same current flow direction, for example, two stages, upper and lower. The shaped coils 15a, 15b are aligned with the central axis Oc.
The upper planar coil 15a, for example, is configured to be rotatable around the central axis Oc.

According to this embodiment, the upper planar coil 15
By appropriately controlling the rotation angle of a, the opposing area between the upper and lower pair of planar coils 15a and 15b can be changed, so the mutual inductance and line capacitance between these two coils 15a and 15b can be changed as appropriate. , the inductance as a whole can be appropriately controlled.

Note that, like the planar inductance element 16 shown in FIG.
One of 6a and 16b may be configured to be able to move eccentrically, and the method of movement is not limited. Further, each of the planar coils 15a, 15b, 16a, 16b may be formed into a circular spiral 17 as shown in FIG. 5, or may be formed into a triangular spiral 18 as shown in FIG. is not limited to.

Furthermore, in the planar inductance element 11 shown in FIG. 2, a case has been described in which the spiral outer peripheries of the upper and lower two stages of planar coils 14a and 14b are connected by the connecting wire 14c, but the present invention is not limited to this. Rather, for example, the spiral inner circumferences (
The two planar coils 14a and 14b may be formed into a spiral shape using a single coated conductive wire by folding back the upper and lower connecting portions of the coils 14a and 14b.

[0035]

[Effects of the Invention] As explained above, the first invention of the present application is
Since the direction of current flowing through the plurality of stacked planar windings is the same, it is possible to reduce the potential difference between adjacent portions of the planar windings.

Moreover, since the plurality of planar windings are made into one set of winding blocks, the plurality of sets are laminated, and an insulator is interposed between each winding block, the withstand voltage against high voltage is sufficiently high. .

In addition, since the withstand voltage is sufficiently high, even if the dielectric withstand voltage slightly decreases due to the temperature rise due to heat generation in the planar winding, there is still a sufficient margin for the withstand voltage, so it is high enough to withstand temperature rises. Gain reliability.

Furthermore, in the second aspect of the invention, the inductance can be appropriately adjusted by moving at least one of the plurality of stacked planar windings and appropriately controlling the opposing areas of these windings.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the first invention of the present application.

FIG. 2 is a partially omitted enlarged view of the main part shown in FIG. 1;

FIG. 3 is a plan view of an embodiment of the second invention of the present application.

FIG. 4 is a plan view of another embodiment of the second invention of the present application.

FIG. 5 is a plan view showing a circular spiral.

FIG. 6 is a plan view showing a triangular spiral.

FIG. 7 is a plan view of a general planar coil.

8 is a longitudinal cross-sectional view of a planar transformer incorporating the planar coil shown in FIG. 7. FIG.

9 is a schematic diagram showing an example of a winding method for the high-voltage side winding shown in FIG. 8. FIG.

FIG. 10 is a schematic diagram showing another method of forming the high-voltage side winding shown in FIG. 8, with some parts omitted;

FIG. 11 is a schematic diagram showing an improved example of the planar coil shown in FIG. 9, with some parts omitted.

FIG. 12 is a graph showing the relationship between the withstand voltage and temperature of a spiral planar coil.

[Explanation of symbols]

11, 15, 16 Planar inductance element 12a~
12c Planar winding blocks 13a, 13b Insulating films 14a, 14b Pair of upper and lower planar coils 14c
contact line

Claims (2)

[Claims] Claim 1: A set of winding blocks is constructed by laminating a plurality of planar windings and forming these windings so that the direction of current flowing through these windings is the same. A planar inductance element characterized in that a plurality of sets of winding blocks are laminated with an insulator interposed between each block. 2. A plurality of planar windings are stacked, these windings are formed so that the direction of current flowing through these windings is the same, and at least one of these planar windings is moved. A planar inductance element characterized by being freely configured.