JPS60177597A - High frequency heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is used in a high-frequency heating device having an electronic control circuit equipped with a microcomputer, and aims to improve safety against induced lightning and performance against noise. It is.

Configuration of the conventional example and its problems FIG. 1 is a diagram showing the conventional example.
A door 2 that can be opened and closed is provided, and a high frequency wave generated from a high frequency generator (hereinafter referred to as a magnetron') 3 is sent into a heating chamber 26 through a waveguide 4. The high frequency heating device 1 includes a power cable 5
AC-100V power is supplied by. Exchange-
Next, from one side of the 100V power line, a gear-type lightning surge absorber wrapped in a tube made of vinyl chloride, etc.
The element unit 1-8 is connected to the metal chassis 9 with screws or the like.As shown in 1, in the conventional example, an electronic control circuit equipped with a microcombi, Gap-type lightning surge absorption element 19 as a countermeasure against induced lightning surge in a high-frequency heating device equipped with a cylinder board 6
The electronic control circuit printed circuit board 6 was not placed on the same board as the printed circuit board 6, but was incorporated into the lead wire) 1-nes, etc. This is because the gap-type lightning surge absorption elements 1 and 9 are discharged due to induced lightning → nozzle voltage, etc., and the microcomputer 7 malfunctions due to the noise. In the worst case, high frequency or automatic oscillation (7. This is because if there were any combustible materials in the heating chamber 26, a fire or the like would occur, creating a very dangerous situation.

Furthermore, when the cap-type lightning surge absorption element 19 is incorporated into a 'J-do wire harness, etc., it is attached to the AC-secondary power line, so it must be insulated from the AC-secondary power line and protected against vibration shock. However, this was one of the reasons for the increase in product prices.

Purpose of the Invention The present invention solves the above-mentioned conventional drawbacks, and improves the safety of a high-frequency heating device having an electronic control circuit equipped with a microcomputer against induced lightning surge voltage and the performance of the electronic control circuit against noise. The purpose is to

Structure of the Invention In order to achieve the above object, the high frequency heating device of the present invention has an induced lightning surge absorbing element and a low voltage transformer for supplying power to a control circuit mounted on an electronically controlled printed circuit board, and a low voltage 1 AC 100cm power is supplied from the AC-secondary power line supply terminal section to the Heranshu to the low-voltage transformer-secondary input section using a copper foil pattern. The AC-order power supply terminal part to the cap type inductive lightning surge absorption element is completely separated from the supply terminal part to the above-mentioned low voltage transformer,
The terminal part is supplied with a copper foil pattern to a cap-type inductive lightning surge absorbing element. Conventionally, a cap-type lightning surge absorbing element is placed on an electronically controlled printer 1 board equipped with a microcomputer. In this case, it has the effect of completely eliminating malfunctions such as automatic oscillation and erroneous display on the display device due to noise caused by absorbing lightning surge voltage and discharging. Furthermore, since the lightning surge absorption element is placed on the printed circuit board, the printed board itself is made of an insulating material such as phenol, so there is no need to add an insulating cover, and the printed circuit board itself is made of an insulating material such as phenol. →)''-Since the shock absorbing element is attached with a handle, it also has the effect of being resistant to vibrations and drops.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In Fig. 2, the metal chassis 9 of the high frequency heating bag @1
Inside, there is a magnetron 3 that generates high frequency waves, and the high frequency output generated from the magnetron 3 is sent into the heating chamber 26 through a waveguide 4. fan motor 10
is for air cooling the magnetron 3 and the high voltage transformer 11. There is a resin operation panel 12 on the front of the high-frequency heating device 1, and a metal support plate 13 that supports the electronic control circuit printed circuit board 6 is provided on the operation panel 12.
is attached, and its metal support plate 13 is completely electrically connected to the metal chassis 9. The operation panel 12 also includes a touch-type flat keyboard switch 1.
4, and the signal obtained there is input to the connection part 15 of the electronic control circuit printed circuit board 6.

FIG. 3 is a view of the electronic component mounting surface of the electronic control circuit printed circuit board 6, and the AC-order 100V power supplied by the AC-order power supply terminal section (hereinafter referred to as connector A) 16 is connected to a low-voltage transformer. 17 to the primary input section 28 . It is supplied to the connector B20 from either one of the AC-order power lines, and is connected to the follow-current prevention resistor 18 from the gear knob type lightning surge absorption element 19.

FIG. 4 shows the copper foil pattern portion of the electronic control circuit printed circuit board 6, and one side power supply line of the microcomputer 7 is provided as a ground pattern A27 on the outer periphery of the printed circuit board 1 to the board.

The AC-order power supply line (either one) to the gap-type lightning surge absorption element 19 and the AC-order electric gap line to the low-voltage transformer 17 are also connected to connector A16 and connector B20 at their supply terminals. Moreover, the copper foil patterns are also completely separated.

The gap type lightning surge absorption element 19 is connected to the ground pattern B21 via the resistor 18.

The ground pattern B21 is electrically connected to the metal support plate 13 by screws A22. or,
The ground pattern A27 is also provided independently of the ground pattern B21, and is electrically connected to the metal support plate 13 by being tightened by the hiss B23 and the hiss C24.

Here, an induced lightning surge voltage of several KV is applied to the power cable 5.
When the light enters the connector A16 and the connector B20 in the high-frequency heating device 1 through Because of its good responsiveness, when the voltage exceeds the discharge starting voltage of the lightning surge absorbing element 19 (generally about 2 KV), the discharge starts and falls from the metal support plate 13 to the metal chassis 9 through the ground pattern B2'1. Since the current change of the surge current containing considerable high frequency components caused by the discharge of this lightning surge absorption element 19 is large, the AC 100
If connector A16 and connector B20, which supply V, are connected and shared by a copper foil pattern, due to the surge current change, a copper foil of about 35 ti will not be able to flow enough current, and the copper foil pattern will have an impedance. , the potential fluctuates, and its influence extends to the low-voltage transformer 17,
Sometimes, the microcomputer malfunctioned, and the power relay 25 was automatically turned on, causing the mag-notrono 3 to oscillate.

The ground pattern B21 and the ground pattern A27 are separated, but this is also to prevent the microcomputer 7 from being affected by potential fluctuations caused by changes in surge current.

According to the present invention, the induced lightning surge absorption element path and the input path of the low voltage transformer 17 are completely separated and independent on the printed circuit board, so that the lightning surge voltage, the high frequency noise generated thereby, and the impedance change of the copper foil pattern are However, it has almost no effect on the low voltage 1 Herance input path, and the microcomputer does not malfunction at all.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) The terminals for supplying AC-secondary power to the low-voltage transformer on the electronic control printed circuit board and the terminals for supplying AC-secondary power to the gap-type lightning surge absorption element are separate, so induced lightning → nozzle There is no effect on the microcomputer such as high frequency noise due to current.

(2) Electronically controlled Zorin [-Since the lightning surge absorption element is mounted on the board, there is no need to perform treatments such as insulation covers compared to when it is installed on the lead wire harness, and it is also resistant to drop vibrations. It will become stronger, the quality will improve, and the cost will become cheaper.

[Brief explanation of drawings]

Figure 1 is a partial cross-sectional perspective view of a conventional high-frequency heating device;
The figure is a cross-sectional view of a high-frequency heating device showing one embodiment of the present invention, FIG. FIG. 4 is a diagram showing the copper foil pattern side of the electronic control circuit printed circuit board shown in FIG. 3; 3... High frequency generator, 6... Electronic control circuit printed circuit board on I-board... Microcomputer, 9... Metal chassis, 12... Operation Panel, 17...Low voltage transformer, 18...
- Resistor for preventing follow-on current, 19...Lightning surge absorption element. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] It is equipped with a heating chamber, a high frequency generator that supplies high frequency waves to the heating chamber, and an electronic control circuit printed circuit board equipped with a microcomputer that controls high frequency output, and on the electronic control circuit printed circuit board, an AC-order power supply line is installed. A lightning surge absorbing element inserted between the heating chamber main body metal chassis and a low voltage I-lance that creates an insulated and transformed AC secondary power source from the AC secondary power source is installed. The high-frequency heating device has a structure in which the two AC-order power supply terminals to Lanos and the AC-order power supply terminal to the lightning surge absorption element are separated.