JPH0347309Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flyback transformer that has an extremely simple structure and is configured to reduce leakage magnetic flux.

Conventionally, a coil section consisting of a low voltage coil wound around a low voltage coil bobbin and a high voltage coil wound around a high voltage coil bobbin coaxially assembled is housed in an insulating case, and consists of a pair of U-shaped core members. A flyback transformer is known in which one opposing portion of the core is located within a core insertion hole of a low-voltage coil bobbin, and the other opposing portion is assembled so as to be located outside the insulating case. Generally, in order for this type of flyback transformer to have high-order resonance, the leakage magnetic flux generated from the opposing portions of the core and the primary side resonant circuit must be balanced, but the leakage magnetic flux is conversely This causes induced voltage to be generated in other coil parts placed on the flyback transformer and in the wiring patterns formed on the printed circuit board on which the flyback transformer is installed, deteriorating the image quality of television receivers, especially monitor receivers. There is a problem.

In order to reduce the above-mentioned leakage magnetic flux, it is sufficient to cover the flyback transformer with a metal plate to form a closed circuit around the flyback transformer.A specific example of this is the structure shown in Japanese Utility Model Publication No. 58-21146. Flyback transformers are known. However, with the method of completely shielding the flyback transformer body using a shield case as shown in the same publication, the entire flyback transformer becomes large. This method has disadvantages in that it cannot meet the requirements of the conventional method, and in that it increases the manufacturing cost of the flyback transformer.

In order to improve these shortcomings, the
As shown in Publication No. 149426, in order to prevent magnetic flux from leaking from the core gap formed at the opposing portions of a pair of U-shaped core members, the outer periphery of the insulating case and the core is raised at a position corresponding to the core gap. There is also known a structure in which it is surrounded by a strip-shaped thin plate having magnetic permeability.

However, the thin plate with high magnetic permeability shown in the same publication,
Because it is a band-shaped metal material for magnetic shielding such as copper or iron,
When the band-shaped metal material is directly wrapped around the outer periphery of the insulating case, a large insulation distance between the high-voltage coil or core and the band-shaped metal material cannot be maintained, leading to dielectric breakdown of the insulating case. Furthermore, there are problems in that it is difficult to position the band-shaped metal material, and furthermore, the winding operation requires a large amount of time.

The present invention was developed in view of the problems of the prior art described above, and it reduces the insulation distance between the high-voltage coil or core and the band-shaped metal member in order to reduce the leakage magnetic flux between the opposing parts of a pair of core members. It is an object of the present invention to provide a flyback transformer that can be secured and positioned with certainty.

In order to achieve this purpose, the present invention adopts a configuration including a cylindrical insulating case made of an insulating material, a coil part consisting of a low voltage coil and a high voltage coil housed in the insulating case, and one side of the insulating case. Generated from a core consisting of a pair of U-shaped core members arranged such that the opposing part is located inside the coil part and the opposing part on the other side is located outside the insulating case, and each opposing part of the core. In order to reduce leakage magnetic flux, the flyback transformer includes the insulating case and a band-shaped metal member wrapped around the outer periphery of the core at a position corresponding to the opposing portion of the core. A step-like separating part is formed integrally with the insulating case on the outer surface of the side, and a skirt-like separating part protruding from the outer surface of the core side so as to sandwich the core is integrally formed with the insulating case. The band-shaped metal member is configured to be wound around the insulating case and core in a non-contact manner via the step-like separation part and the skirt-like separation part.

With this configuration, the metal member is wrapped in an annular manner at a position corresponding to each opposing portion of the core formed by the integral U-shaped core member, so that a magnetic and electrical closed circuit can be created. is formed, effectively reducing leakage magnetic flux. At this time, since the stepped separation part and the skirt-shaped separation part are integrally formed in the insulation case, the insulation distance between the high voltage coil and core and the band-shaped metal member is ensured, and the positioning of the band-shaped metal member is made easy. Become certain.

An embodiment of the present invention will be described below based on the drawings.

In the figure, reference numeral 1 denotes an insulating case made of an insulating material and having a substantially cylindrical cross section with both ends closed. A coil portion 2 is housed within the insulating case 1. As shown in FIG. Here, the coil portion 2 is a cylindrical low-voltage coil bobbin 2.
It consists of a low voltage coil 2B wound around A, and a high voltage coil 2D wound around a cylindrical high voltage coil bobbin 2C provided coaxially with the low voltage coil bobbin 2A, and the low voltage coil bobbin 2A has a core insertion hole 3. is formed. The coil portion 2 configured as described above is housed in the insulating case 1 and then molded with an insulating member.

4 is a core, the core 4 is composed of a pair of core members 5 and 6 each having a U-shape;
6 positions one of the parallel pieces 5A, 5B and 6A, 6B in the insertion hole 3 of the low voltage coil bobbin 2A, and the parallel pieces 5B, 6B on the other side.
are arranged outside the insulating case 1 so as to face each other. and parallel pieces 5 on each side
Opposed parts 5A', 6 of A, 6A and 5B, 6B
By providing a slight gap between A' and between 5B' and 6B', core gaps 7A and 7B are formed for adjusting the characteristics of the flyback transformer, and each core gap 7A and 7B is covered with an insulating film, etc. The thin film insulating members 8, 8 are connected to each opposing portion 5A',
It is sandwiched in close contact with 6A', 5B', and 6B'.

Reference numerals 9A and 9B denote a pair of step-shaped separation parts located on opposite sides of the core 4 and formed in steps on the outer surface of the insulating case 1 from the outer center to the lower end and having a substantially U-shaped cross section; Concave grooves 10A and 10B are formed on the arcuate outer surfaces of the separation parts 9A and 9B, into which a band-shaped metal member 12, which will be described later, is fitted and positioned. Reference numerals 11A and 11B indicate skirt-like separation parts that protrude from the center of the outside of the insulating case 1 on both sides of the core 4 so as to sandwich the core 4;
A, 11B and a stepped separation part 9A formed in a U-shape,
9B is integrally formed in the insulating case 1 at positions corresponding to the core gaps 7A and 7B.

12 denotes each of the separating parts 9A, 9B and 11A,
A highly conductive band-shaped metal member is wound so as to surround the core gap 7A, 7B in a non-contact state with respect to the insulating case 1 and the core 4 via the insulation case 11B.
The band-shaped metal member 12 is made of a material that has a low specific electrical resistance, allows easy flow of eddy currents generated by leakage magnetic flux, and generates less heat due to eddy current loss;
For example, it is preferable to use a copper plate having a thickness of about 0.1 to 0.3 mm formed into a belt shape and connected at both ends to form an annular shape.

Note that 13, 13, . . . are pin-shaped terminals of the low voltage coil 2B, and 14 is an anode lead wire for connecting the high voltage coil 2D to the television receiver.

According to this embodiment configured as described above, by winding the band-shaped metal member 12 annularly around the insulating case 1 in which the coil portion 2 is housed and a portion of the outer side of the core 4, the wires are removed from the core gap 7A, 7B. The leaking magnetic flux can be shielded in the same way as in the prior art. Moreover, core gap 7A, 7
By wrapping the band-shaped metal member 12 around B, the leakage magnetic flux can be reduced by about 80%. Further, according to this embodiment, the band-shaped metal member 1
2 is a stepped separation part 9 for the insulation case 1 part.
A, 9B are wound in a non-contact state, and the insulation distance between the band-shaped metal member 12 and the high voltage coil 2D is maintained, so that the withstand voltage of the insulation case 1 can be maintained. Dielectric breakdown can be prevented.

Further, according to the present embodiment, each of the separating parts 9A, 9B and 11A, which are integrally formed with the insulating case 1,
Since the configuration is such that the band-shaped metal member 12 is simply wound around the metal member 11B, the number of parts is reduced, and the wrapping can be easily performed using an automatic binding device, etc., which significantly improves manufacturing efficiency. You can make better plans.

Furthermore, in this embodiment, the core gap 7A,
7B, thin film-like insulating members 8, 8 are connected to each opposing portion 5A',
6A', 5B', and 6B', the band-shaped metal member 12 according to this embodiment can also be used in a flyback transformer in which the core gap is formed wider. Since the wide core gap can be effectively covered, the insulating case 1 and the band-shaped metal member 12 can be standardized.

Note that in this embodiment, the band-shaped metal member 12
are grooves 10A formed in stepped separation parts 9A and 9B,
10B, but the grooves 10A and 10B may not be formed and the band-shaped metal member 12 may be fixed to the stepped separation parts 9A and 9B with an adhesive for positioning. . Further, in the embodiment, the band-shaped metal member 12 is provided so as to surround the core gap, but the band-shaped metal member 12 may be provided near the core gap at a position that receives leakage magnetic flux from the core gap.

According to the present invention configured as detailed above,
On the outside of the insulating case, a step-like separating part is integrally formed on the side opposite to the core, and a skirt-like separating part is integrally formed on the core side so as to sandwich the core, and the band-shaped metal member covers each of these separating parts. Since the structure is such that the insulating case and core are wound in a non-contact manner through the insulating case, it is possible to maintain the insulation distance between the high voltage coil and the core and the high voltage coil, increasing the withstand voltage of the insulating case and preventing dielectric breakdown. can be prevented. In addition, the band-shaped metal member only needs to be wound around each separated portion, and it is possible to reliably position the metal member and to perform automatic winding using an automatic binding device. Furthermore, since the step-like separation part and the skirt-like separation part can be resin-molded integrally with the case, the number of parts can be reduced, manufacturing costs can be reduced, and the flyback transformer can be made smaller. It has a great effect.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a flyback transformer according to an embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view of the flyback transformer showing the position at which a band-shaped metal member is wound. 1...Insulation case, 2...Coil part, 2B...
Low voltage coil, 2D...high voltage coil, 4...core,
5, 6... Core member, 5A', 5B', 6A', 6
B'...Opposing part, 9A, 9B, 11A, 11B...
...Separation part, 12... Band-shaped metal member.

Claims (1)

[Scope of utility model registration request] A coil section consisting of a cylindrical insulating case made of an insulating material, a low voltage coil and a high voltage coil housed in the insulating case, an opposing section on one side located within the coil section, and an opposing section on the other side. A core consisting of a pair of U-shaped core members arranged so that the core members are located outside the insulating case, and a core that corresponds to the opposing portions of the core in order to reduce leakage magnetic flux generated from each opposing portion of the core. In a flyback transformer comprising the insulating case and a band-shaped metal member wrapped around the outer periphery of the core, the insulating case has a step-like separation part integrally formed with the insulating case on the side opposite to the core. Further, the insulating case is integrally formed with a skirt-shaped separation part protruding from the outer surface on the core side so as to sandwich the core, and the band-shaped metal member is connected to the stepped separation part and the skirt. A flyback transformer characterized in that the flyback transformer is configured to be wound around the insulating case and the core in a non-contact manner via a spaced part.