JPH11144858A - Inverter power supply for high frequency heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure an insulation distance of an inverter power supply for a high-frequency heating device and to prevent damage to a printed circuit board, and to achieve a high-density design and a relaxation of a bending moment applied to the printed circuit board. It is. SOLUTION: To ensure insulation between a radiation fin 3 and a step-up transformer 4 and to apply a part of a load of the step-up transformer 4 to the radiation fin 3 to reduce a bending moment applied to a printed circuit board 1. In addition, the heat radiation fin 3 and the step-up transformer 4 are mechanically fitted with an electrically insulating material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter power supply for a high-frequency heating device, and more particularly to an insulating structure and a supporting structure of a radiation fin having a potential and a step-up transformer.

[0002]

2. Description of the Prior Art As shown in FIG.
It has a radiating fin 3 for radiating heat loss of the power semiconductor 2 provided thereon and a step-up transformer 4 for supplying power to a magnetron which is a high frequency generator, and a package of the power semiconductor 2 has a thermal resistance. A space for insulating the heat radiation fins 3 having a potential and the step-up transformer 4 having the grounded core 5 because the package is a non-insulating type so as to keep the temperature low. It was provided on the printed circuit board 1 by opening.

[0003]

However, in the conventional inverter power supply for a high-frequency heating device, the insulation between the radiation fin having a potential provided on a printed circuit board and the step-up transformer having a grounded core is provided. It was necessary to ensure that the distance always met the prescribed insulation distance. For this reason, there is a problem that the occupied area on the printed circuit board is inevitably increased because the design is made in consideration of the variation in the mounting, the decrease in the insulation distance due to the drop vibration generated during transportation of the finished product, and the like. .

Further, since a heavy transformer is independently provided on the printed circuit board, there is a problem that the printed circuit board is liable to be damaged by stress due to drop vibration or the like generated during transportation of a finished product. .

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention combines a radiation fin having a potential provided on a printed circuit board and a step-up transformer grounded via an electrically insulating material to form an integral unit. The configuration is such that:

Since the distance between the radiation fins and the step-up transformer can be fixed at a constant value by the above configuration, the distance can be made the minimum distance required for insulation. Further, since the stress generated by the drop vibration at the time of transportation of the finished product or the like can be dispersed to the radiation fins and the step-up transformer via the insulating material, the printed circuit board is not easily broken.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a printed circuit board, a radiation fin having a potential provided on the printed circuit board, and a step-up transformer grounded, and an insulation between the radiation fin and the step-up transformer. In order to reduce the bending moment applied to the printed circuit board by applying a part of the load of the step-up transformer to the radiation fins,
The radiation fins and the transformer are connected with an electric insulating material to be integrated.

Further, since the radiation fins and the printed circuit board are connected via an electrical insulating material to be integrated and fair, the insulation distance between the two can be minimized, and the size can be reduced. Since the stress applied to the printed circuit board during transportation or the like can be dispersed between the radiation fins and the step-up transformer, the printed circuit board can be hardly damaged.

Further, a part of a coil bobbin made of a thermoplastic resin used for a step-up transformer is used as an electric insulating material.

Since the coil bobbin of the step-up transformer is used as the electric insulating material, it can be easily obtained by a method such as integral molding at the time of molding.

Further, the coil bobbin is configured to be fitted with one or more fins of the radiation fin. By mechanically fitting one or more fin portions of the radiation fins having a potential with a part of a coil bobbin formed of a thermoplastic resin of a step-up transformer, drop vibration or the like generated during transportation of a finished product, etc. By dispersing the stresses in the step-up transformer and the radiation fins, it is possible to prevent the printed circuit board from being damaged.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

Here, the same reference numerals in the drawings as those having the same functions as those of the conventional example are used. (Example 1) FIG.
1A and 1B are a top view and a sectional view of a main part of an inverter power supply for a high-frequency heating device according to a first embodiment of the present invention.

Referring to FIG. 1, reference numeral 1 denotes a printed circuit board made of paper phenol as an inverter power supply for a high-frequency heating device. On the printed circuit board 1, a power semiconductor 2 which is an insulated gate bipolar transistor (IGBT) of a non-insulated type package is provided. It has a radiation fin 3 made of aluminum for radiating heat generated by heat loss, and a step-up transformer 4 for supplying heater power to a magnetron as a high-frequency generator, and the step-up transformer 4 is made of a thermoplastic resin such as polyethylene terephthalate. And a core 5 made of a magnetic material made of a ferrite core grounded, and a primary winding 7 and a secondary winding 8 formed of magnet wires.

Here, the step-up transformer 4 of the radiation fin 3
This configuration is such that the fins 9 on the side and the ribs 10 of the coil bobbin 6 on the primary winding 7 side of the step-up transformer 4 are in mechanical contact.

Next, the operation will be described. Even if the positional relationship between the radiating fin 3 and the step-up transformer 4 is displaced due to a variation in the mounting of the radiating fin or the step-up transformer, or a drop vibration generated during transportation of the finished product, the position of the radiating fin 3 is increased.
The fins 9 and the ribs 10 of the coil bobbin 6 of the step-up transformer 4 regulate the displacement. Therefore, the radiation fins 3 having the potential generated by the power semiconductor 2 of the non-insulating type package and the grounded core of the step-up transformer 4 are formed. 5 can always be kept constant. Therefore, the distance between the radiating fins 3 and the step-up transformer 4 can be disregarded due to variations in mounting and the effects of drop vibrations generated during transportation of finished products, and the insulation distance between the radiating fins and the step-up transformer can be minimized. can do.

(Embodiment 2) FIG. 2 is a sectional view of a main part of an inverter power supply for a high-frequency heating apparatus according to Embodiment 2 of the present invention.

The difference from the first embodiment is that a hole 12 is provided in the fin 11 of the heat radiation fin 3 on the side of the step-up transformer 4, and the coil bobbin 6 on the primary winding 7 side of the step-up transformer 4 is provided.
Is that the ribs 13 have claws 14.

The components having the same reference numerals as in the first embodiment have the same structure, and the description is omitted. Next, the operation will be described. In addition to the effect of the first embodiment, the rib 13 of the step-up transformer 4 is fitted to the fin 11 of the heat radiation fin 3, and the rib 13 is fitted to the hole 12 provided in the fin 11. By fitting the provided claws 14, with respect to the figure,
Moment in the vertical and horizontal directions due to drop vibration and the like generated during transportation of the finished product is divided by both the radiation fins 3 and the step-up transformer 4, and the printed circuit board 1 is a heavy transformer.
Can be reduced.

It is needless to say that the same effect can be obtained with respect to the configuration of the first embodiment as to the moment in the vertical direction with respect to the drawing.

[0021]

As described above, according to the present invention, the insulation distance between the radiation fin and the step-up transformer is defined by keeping the insulation distance between the radiation fin having a potential and the grounded metal part of the step-up transformer constant. Since the distance can be minimized, the inverter power supply circuit can be downsized.

Also, by mechanically fitting one or more fin portions of the radiation fins having a potential with a part of a coil bobbin formed of a thermoplastic resin of a step-up transformer, a finished product can be transported. By dispersing the stress caused by the dropping vibration and the like to the step-up transformer and the radiating fins, it is possible to prevent the printed circuit board from being damaged.

[Brief description of the drawings]

FIG. 1A is a top view of an inverter power supply for a high-frequency heating device according to a first embodiment of the present invention. FIG.

FIG. 2 is a sectional view of a main part of an inverter power supply for a high-frequency heating device according to a second embodiment of the present invention.

FIG. 3 is a top view of a conventional inverter power supply for a high-frequency heating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed circuit board 3 Heat dissipation fin 4 Step-up transformer 6 Coil bobbin 9 Fin

Claims (3)

[Claims] 1. A printed circuit board, comprising: a radiation fin having a potential provided on the printed circuit board; and a step-up transformer grounded, ensuring insulation between the radiation fin and the step-up transformer, and In order to apply a part of the load of the step-up transformer to the radiating fins and reduce a bending moment applied to the printed circuit board, the radiating fins and the transformer are joined by an electrically insulating material to be integrated with each other. Inverter power supply for high frequency heating equipment. 2. The inverter power supply for a high-frequency heating apparatus according to claim 1, wherein a part of a coil bobbin made of a thermoplastic resin used for a step-up transformer is used as an electric insulating material. 3. The inverter power supply for a high-frequency heating device according to claim 1, wherein the coil bobbin has a configuration in which one or more fins of the radiation fins are fitted.