JPH0229698Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention relates to a small transformer.

``Prior Art'' Conventionally proposed small transformers have a structure in which a primary winding and a secondary winding are wound around a core body having flanges on both ends and a substantially rectangular outer shape. ing. The plates that make up these flanges and cores need to be at least 0.3mm thick for molding purposes, and even if you try to make the transformer smaller by using the plates, it is difficult to make the plates any thinner. be. Therefore, in order to further reduce the size of a small transformer, it is necessary to take into consideration its basic structure and eliminate unnecessary occupied space.

``Problems to be solved by the invention'' This invention aims to solve the problems with conventional small transformers, and the basic structure of the transformer is different from that previously proposed, and it is equipped with a bobbin. Furthermore, the present invention provides a compact transformer which has a configuration in which all wasted occupied space can be eliminated, and whose overall size is reduced to a substantially cubic shape without deteriorating the operating characteristics of the transformer.

"Structure of the invention" In this invention, a substrate is formed of an insulating material into a substantially rectangular plate shape, and first and second cores are arranged on opposing edges of one surface of the substrate substantially at right angles to this surface. A receiving portion is integrally formed to protrude. A plurality of terminals are planted on the other surface of the substrate at the position of the core receiving portion.

The first and second coils are formed into a cylindrical shape as a whole, and are disposed on the substrate parallel to and coaxially with the substrate, and both end surfaces are connected to the first and second core receiving portions on the substrate. The core receiving portion is fitted between the first and second core receiving portions so as to face each other.

A cylindrical part is fitted and inserted into the first and second coils, and rectangular first and second holding parts are connected to both end surfaces of the cylindrical part. These first and second holding parts are disposed opposite to each other on the first and second core receiving parts.

The first one on the side away from the first and second core receiving parts
and the ends of the second holding part are connected to each other, the inner surfaces are in contact with the outer peripheral surfaces of the first and second coils, and the second holding part is divided into two in the arrangement direction of the first and second core receiving parts. A connection part is formed by connecting two objects. The cylindrical portion, the first and second holding portions, and the connecting portion constitute a magnetic core.

``Example'' Hereinafter, the small transformer of this invention will be described in detail based on an example using the drawings.

FIG. 1 shows the structure of a substrate and a core receiving portion used in an embodiment of this invention. A substrate 11 is formed of an insulating material into a substantially rectangular plate shape. The opposing edge portions of one surface of the substrate 11 are integrally projected at right angles to the one surface to form first and second core receiving portions 12-1 and 12-2. A plurality of terminals 13-1 to 13-6 are planted on the other surface of the substrate 11 at positions where the first and second core receiving portions 12-1 and 12-2 protrude.

First and second core receiving parts 12-1, 12-2
These terminals 13-1 to 13-
Guide recess 1 in the direction opposite to the direction in which the terminal protrudes from between 6 and 6.
4-1 to 14-4 are formed to be extended, and the ends of the extended guide recesses 14-1 to 14-4 are connected to the first and second guide recesses 14-1 to 14-4.
It reaches the inner surface of the core receiving portions 12-1 and 12-2. Further, a recess 15 having a predetermined curvature is formed in the center of one surface of the substrate 11 .

Substrate 11 and first and second core receiving parts 12-
1, 12-2 does not use a special split mold,
High-quality molded products can be easily mass-produced. Furthermore, while holding the board 11 part in the assembly process, the terminal 1 is held against the other surface of the board 11.
3-1 to 13-6 can be easily planted.

As shown in FIG. 2, the first and second coils 30 are formed substantially entirely in a cylindrical shape. This first
The second coil 30 is fitted coaxially and parallel to the substrate between the first and second core receiving parts with both end surfaces thereof facing the first and second core receiving parts. Ru. In the embodiment shown in FIG. 2, the first and second coils 30 are wound with the low voltage side primary winding 20 on the inside and the high voltage side secondary winding 25 on the outside.

As the primary winding 20, for example, a fusion wire with a diameter of 0.23 mm is used, and it is wound a predetermined number of times on a winding shaft with a predetermined diameter, and after winding, the fusion paint applied on the insulating paint is heated and fused. to secure the winding. An insulating tape 21 is fixedly wound on the winding peripheral surface of the primary winding 20. At this time, the lead wires 22 and 23 from both ends of the primary winding 20
are pulled out along the circumferential surface of the winding shaft in directions facing each other with respect to the axis. The winding shaft is pulled out from the primary winding 20 that has been completely wound to form a cylindrical first coil.

A secondary winding 25 is mounted on a winding shaft having a diameter slightly larger than the outer diameter of the first coil formed by the primary winding 20.
For example, a fused wire with a diameter of 0.04 mm is wound a predetermined number of times. After winding a predetermined number of times, the adhesive paint is fixed to the winding by heating and fusing, and an insulating tape 27 is wound on the winding peripheral surface of the secondary winding 25. One end of the secondary winding 25 is pulled out to the side at right angles to the circumferential surface of the winding shaft. Pull out the winding shaft from the completed secondary winding 25,
A cylindrical second coil is formed.

Since the diameters of the winding shafts used for winding the primary winding 20 and the secondary winding 25 are each selected to predetermined values, the first coil is placed inside the second coil wound in a cylindrical shape. The first and second coils 30 are configured by fitting them together. The length in the axial direction of the first and second coils 30 formed in a cylindrical shape is slightly smaller than the length between the opposing inner surfaces of the first and second core receiving parts 12-1 and 12-2. formed short. Further, the cylindrical radius of the first and second coils 30 and the radius of curvature of the recess 15 of the substrate 11 are set to be approximately equal.

When forming the first and second coils 30, an auxiliary winding may be wound. In this case, the fifth
As shown in the figure, for example, the diameter is
A 0.1 mm auxiliary winding 40 is wound so as to be located in the concave portion of the adjacent portion of the primary winding 20.
Insulating tape 41 is wound on the winding surface of 0. In this way, the auxiliary winding 40 can be wound without wasting occupied space.

The second coil formed as described above is fitted onto this insulating tape 41. In this case, the diameter setting of the winding shaft used for winding the primary and secondary windings 20, 25 is slightly adjusted due to the presence of the auxiliary winding 40.

The first and second coils 30 formed in a cylindrical shape in this manner have their circumferential surfaces facing the recess 15,
First and second core receiving portions 12 are provided on both end surfaces, respectively.
-1, 12-2 so that it is in contact with the inner surface,
It is held by a magnetic core and attached to the substrate 11.

As shown in FIG. 3, the magnetic core has a cylindrical portion 32,
The first and second holding parts 33 and the connecting part 31 are assembled so as to face each other at the end faces of the connecting part 31 and the cylindrical part 32.
The magnetic core having such a bisected shape is fitted and assembled into the first and second coils 30 from both ends in the axial direction at the cylindrical portions 32,
In this state, it is attached to the substrate 11.

That is, a cylindrical part 32 whose diameter is slightly smaller than the inner diameter of the first and second coils 30 is formed, and is connected to the end face of this cylindrical part 32.
A substantially rectangular holding portion 33 is formed perpendicular to the axis of the holding portion 33 . One peripheral edge of this holding part 33 is the columnar part 32
The connecting portion 31 is formed by bending and extending in the extending direction. A recessed portion 35 having a curvature equal to the diameter of the first and second coils 30 is formed on the plate surface of the connecting portion 31 facing the columnar portion 32 . End surface 31- of the cylindrical part 32 and the connecting part 31 in the protruding extension direction
P and 32-P are formed to exist on the same plane.

The other half shape is formed, which has a shape symmetrical to the one half shape shown in FIG. 3, and has end surfaces 31-P and 32-P disposed in opposition to each other. The magnetic core thus divided into two by the connecting portion 31 and the columnar portion 32 is fitted into the first and second coils 30 from both end faces in the axial direction. The cylindrical portions 32 are fitted and inserted into the first and second coils 30 from both end sides, and the end faces 31-P and 32-P are each bonded to the other end face by adhesive means. In this way, the magnetic core holding the first and second coils 30 positions the holding part 33 on the first and second core receiving parts 12-1 and 12-2, respectively, and It is fixed to the core receiving parts 12-1 and 12-2 by adhesive means, for example, and attached to the substrate 11.

In this attached state, the recess 35 of the connecting portion 31 is in contact with the outer peripheral surfaces of the first and second coils 30, and the connecting portion 31 is in contact with the first and second core receiving portions 12-1 and 12-2, respectively. It is arranged so as to cover the first and second coils 30 from the side.

As shown in FIG. 4, the shape after assembly is completed is approximately cubic, and there is no wasted occupied space, making it possible to significantly downsize the entire structure. According to the results of actual measurements by the inventors, it was possible to obtain a transformer with a smaller cubic shape of 6 x 6 mm and to have transformer characteristics equivalent to those of a conventional one with an outer size of 8 x 8 mm.

When an auxiliary winding 40 is provided as shown in FIG. 5, it is possible to use this auxiliary winding 40 to configure, for example, a transistor or an inverter circuit.

FIG. 6 shows an example of a circuit, in which one end of the auxiliary winding 40 is connected to the base of a transistor 51, and the other end is connected to one end of the primary winding 20 via resistors 52 and 53. The other end of primary winding 20 is connected to the collector of transistor 51. A DC power supply 54 and a switch S are connected in series between the connection point between the resistor 53 and the primary winding 20 and the emitter of the transistor 51. Furthermore, a capacitor 55 and a resistor 56 are connected in parallel between the emitter of the transistor 51 and the connection point between the resistors 52 and 53.

Assuming that the capacitance of the capacitor 55 is C ₁ and the resistance value of the resistor 56 is R ₁ , the time constant C ₁ R ₁ determines the cut-off time of the transistor 51 during one cycle of the circuit shown in FIG. Output is taken out between output terminals t ₁ t ₂ of 25. Pass this output through a diode,
It is possible to construct the known flash tube light emitting circuit with storage in a capacitor.

The compact transformer of this invention does not require a bobbin due to its structure, and the space required for the thick part of the conventional bobbin can be used for the primary and secondary windings and the magnetic core, making the overall shape significantly smaller. Miniaturized. Since the terminals are mounted on one side of the board 11 in a concentrated manner, mounting on the printed circuit board is easy.

Cylindrical part 32 and holding part 33 that constitute the magnetic core
and a connecting portion 31 are integrally formed, and the first and second connecting portions are integrally formed.
The magnetic cores are assembled to the first and second coils 30 from both ends in the axial direction of the coil 30, and the magnetic cores are attached to the first and second core receiving portions 12-1, 12 of the substrate 11.
Since the holding portion 33 is positioned on the substrate 11 and fixed to the substrate 11, the entire assembly can be performed easily and efficiently. In addition, it is possible to have a compact overall configuration with an approximately cubic shape without using a special case.

In the embodiment, the first and second coils 30 are wound with the primary winding on the inside and the secondary winding on the outside.
However, as long as conditions are set to satisfy insulation, the first and second coils 30 can be wound by winding the secondary winding on the inside and the primary winding on the outside.
It is also possible to implement the following configuration.

"Effects of the Invention" As explained in detail above, according to this invention, it is possible to provide a compact transformer that is easy to assemble and manufacture, is significantly miniaturized as a whole, and has excellent transformer characteristics.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the structure of the substrate and core receiving part of the embodiment of this invention, FIG. 2 is a perspective view showing the shapes of the first and second coils used in the embodiment of this invention, Fig. 3 is a perspective view showing the configuration of the magnetic core in the embodiment of this invention, Fig. 4 is a perspective view showing the structure of the embodiment of this invention, and Fig. 5 shows the structure of the first and second coils. FIG. 6, a diagram showing an example of the configuration, is a circuit diagram when the small transformer of this invention is used in a transistor and an inverter circuit. 11: Board, 12-1, 12-2: Core receiving part, 13-1 to 13-6: Terminal, 14-1 to 14
-4: Guide recess, 15: Recess, 20: Primary winding,
21: Insulating tape, 22, 23: Leader line, 25:
Secondary winding, 27: Insulating tape, 30: First and second coils, 31: Connecting portion, 32: Cylindrical portion, 3
3: Holding part, 35: Recessed part, 31-P, 32-P:
End face.

Claims (1)

[Claims for Utility Model Registration] A substantially rectangular plate-shaped substrate made of an insulating material, and a first plate integrally formed on opposing edges of one surface of the substrate and projecting substantially at right angles to the one surface. and a second core receiving part; and a plurality of terminals planted on the other surface of the substrate at the positions of these core receiving parts; The first and second core receiving parts are arranged to face the second core receiving part and fit between the first and second core receiving parts, and are arranged parallel to and coaxially with the substrate. a coil, a cylindrical part fitted and inserted into the first and second coils, and a cylindrical part formed continuously on both end faces of the cylindrical part, and said first and second core receivers. substantially rectangular first and second holding parts disposed facing each other on the part, and ends of the first and second holding parts remote from the first and second core receiving parts are mutually arranged. a connecting portion formed by connecting two pieces of the first and second core receiving portions that are connected to each other in the arrangement direction of the first and second core receiving portions, the inner surfaces of which are in contact with the outer circumferential surfaces of the first and second coils; A small transformer characterized by having a magnetic core composed of.