JPH0635452Y2 - High frequency transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to the structure of a small high-frequency transformer used as, for example, a power transformer of a DC-DC converter.

[Conventional technology]

The applicant previously proposed Japanese Patent Application No. 1-196092 of a high frequency transformer in which a plurality of flat conductor wires are laminated to improve the coupling coefficient.

FIG. 3 shows an embodiment thereof, and 3 is a core having a T-shaped cross section in which a winding shaft 3a is integrally formed in the center. A primary winding 1 and a secondary winding 2 which are both flat conductors are wound around a winding shaft 3a with a wide surface overlapped with each other via an insulator (not shown). The primary winding 1 and the secondary winding 2 have different numbers of turns,
Only the longer primary winding 1 is wound under the winding shaft 3a. The U-shaped second core 4 is abutted and fixed to the core 1.

[Problems to be solved by the device]

In power transformers such as DC-DC converters, it is common to provide small gaps in the magnetic circuit to avoid magnetic saturation. In the case of the transformer shown in FIG. 3, gaps are formed at points A1, A2, A3, etc.

When the numbers of turns of the primary winding 1 and the secondary winding 2 are different, there will be a portion where these windings do not overlap with each other. As shown in the figure, the end 1a of the primary winding 1 on the non-overlapping side has a gap
When located near A1 and A3, the amount of magnetic flux interlinking the leakage flux around these gaps is different between the primary winding 1 and the secondary winding 2, so the coupling coefficient as a transformer decreases. was there.

[Purpose of device]

An object of the present invention is to further improve the coupling coefficient between windings in a low-profile transformer having windings made of flat conductor wires and having primary windings, secondary windings, etc. having different numbers of turns. To do.

[Means for Solving the Problems]

According to the present invention, a first core having an E-shaped cross section having a winding shaft, a second core having an I-shaped cross section, and a wide surface being substantially perpendicular to the central axis of the winding shaft of the first core. A high frequency transformer having at least two flat conductor wires spirally wound around a winding shaft, wherein the tip end of the winding shaft of the first core is abutted against the second core with a slight gap therebetween; The number of windings of the conductor wire on the winding shaft is different, and two conductor wires are laminated on the tip end side of the winding shaft with the wide surfaces over each other with the insulating layer interposed therebetween. A feature is that only the conductive wire is continuously wound.

〔Example〕

FIG. 1 is a front sectional view showing an embodiment of a transformer according to the present invention, and FIG. 2 is a partially exploded perspective view.

A core 10 made of a magnetic material having an E-shaped cross section has a cylindrical winding shaft 12 protruding in the center. The winding shaft 12 is composed of two foil-shaped conductors 30, which are laminated via an insulating layer (not shown).
40 is spirally wound with its wide surface substantially perpendicular to the central axis E of the winding shaft 12 of the core.

The conductor wire 30 and the conductor wire 40 are wound around the winding shaft 12 different times,
Each of them constitutes a primary winding and a secondary winding of a transformer. One ends of the two conductors are stacked on top of each other with a wide surface over the insulating layer, and the longer conductor 40 is provided below the winding shaft 12.
It is only wound. The terminals 32 and 42 drawn out from the conductors 3 and 40 are wound around the end edges of the core 10 and fixed by adhesion to form surface connection type terminals.

On the core 10, a second core 20 having an I-shaped cross section is fixed to each other by means such as adhesion. Although not shown in the drawing, a small gap is formed at the joints indicated by B1, B2, and B3 in FIG. 1 by sandwiching a plastic sheet.

In order to obtain the conductors 30 and 40 wound around the core 10 so that the wide surfaces thereof are substantially perpendicular to the central axis E of the winding shaft 12 of the core, the conductors 30 and 40 coated with the insulating layer are temporarily provided. It is possible to form a winding shape by winding and winding it into a cylindrical shape, and inserting this into the winding shaft 12.

As described above, according to the present invention, in a transformer having a plurality of windings with different numbers of turns, each winding has flat conductor wires that are alternately spiraled so that the wide surface is substantially perpendicular to the central axis of the winding shaft. In addition to the winding configuration, the side where a plurality of windings are laminated is located near the gap between the two cores.

[Effect of device]

According to the present invention, there is almost no difference between the windings in the amount of magnetic flux that causes leakage flux around the gap to interlink with the windings.
This has the effect of further improving the coupling coefficient between the windings.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of a transformer according to the present invention, FIG. 2 is a partially exploded perspective view, and FIG. 3 is a front sectional view of a conventional example. 10 ・ 20 …… Core 12 …… Roller 30 ・ 40 …… Conductor wire B1, B2, B3 …… Gap

Claims (1)

[Scope of utility model registration request] 1. A first core having an E-shaped cross section having a winding axis, a second core having an I-shaped cross section, and a wide surface substantially perpendicular to the central axis of the winding axis of the first core. And at least two flat conductive wires that are spirally wound around the winding shaft.
In a high-frequency transformer in which the tip of the winding shaft of the core is abutted against the second core with a slight gap, the number of windings of the two conducting wires around the winding shaft is different, and two windings are provided on the tip side of the winding shaft. The conductors are stacked on top of each other with a wide surface over the insulating layer,
A high-frequency transformer characterized in that only the longer conductor wire is continuously wound on the other end side of the winding shaft.