JPS62117294A - Radio 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 Field of Industrial Application The present invention relates to an improvement in a high-frequency heating device for performing so-called induction heating such as a heavy ion microwave oven.
This invention relates to an improvement in a high-frequency heating device configured to generate high-frequency power using an inverter, boost the voltage using a step-up transformer, and pivot a magnetron.

BACKGROUND OF THE INVENTION Various configurations of high-frequency heating devices of this type have been proposed in order to reduce the size, weight, or cost of the power transformer.

FIG. 4 is a circuit diagram of a conventional high frequency heating device. In the figure, power from a commercial power supply 1 is rectified by a diode bridge 2 to form a unidirectional power supply 3. 4 is an inductor, and 5 is a capacitor, which plays the role of a filter against high-frequency switching and switching movements of the inverter.The inverter includes a resonance capacitor 6, a step-up transformer 7, a transistor 8, a diode 9, and a drive circuit 10. The transistor 8 is the electric circuit 1.
From 0 (JF: JF: switching operation is performed with a constant cycle and duty (i.e., on/off time ratio) by the supplied base-E current. As a result, high-frequency high-voltage power is generated on the output side of the step-up transformer 7. The high-frequency high-voltage rectifier is rectified by the capacitor 11 and the diode 12 and supplied between the anode and cathode of the magnetron 13, while the high-frequency low voltage is supplied to the power sword heater from the step-up transformer 7.Therefore, the magnetron 13 oscillates and heats the dielectric. In such a configuration, the core cross-sectional area of the step-up transformer 7 becomes smaller as the frequency of the supplied power increases.
When operating at a frequency of about toOKHz, the weight of the step-up transformer is lower than when boosting the voltage at the commercial power frequency.
It has the advantage that the size can be reduced from a few minutes to a few minutes, and the cost of the power supply section can be reduced. Capacitor 14°15.16 and inductance 17.
18 constitutes a filter for unnecessary radiation of the magnetron 13.

FIG. 5 shows a cross-sectional view of a conventional high-frequency heating device.

Elements corresponding to those in FIG. 4 are given the same symbols. Fifth
In the figure, the microwave generated from the magnetron 13 is fed into the oven 19 by 1.1ξ.

The cooling fan 20 serves to cool the magnetron 13 and also the step-up transformer 7. The magnetron 13, high voltage capacitor 11, diode 12, step-up transformer 7, drive circuit 10, rectifier circuit 21, etc. are connected to the power supply, and the ground potential is connected to the oven body 22.
The potential is the same as that of

Problems to be Solved by the Invention However, such conventional high frequency heating devices have the following drawbacks.

In order to make the step-up transformer smaller, 'direct source circumference l'J! j,
Since the number is converted to a high frequency, terminal noise is generated from the inverter power supply unit 23 to the commercial power supply 1, and provides noise protection to the equipment. Furthermore, there was a problem in that the single burst of the magnetron had an adverse effect on the communication system. In addition, although step-up transformers have become smaller, the number of components such as the inverter section and rectifier circuit section has increased, making it difficult to create a compact high-frequency heating device as a whole. Therefore, noise was likely to occur.

In addition, in terms of cooling, there was also a problem in that it was troublesome to efficiently cool the circuit components, the step-up transformer, the magnetron, and other separate components.

In addition, there is a problem in that the drive circuit malfunctions due to unnecessary radiated electric fields generated by the magnetron.

Means for Solving the Problems The present invention has been made to solve the drawbacks of such conventional high frequency heating devices, and is a high frequency heating device constructed by the means described below.

That is, a rectifier that converts a commercial power source into a unidirectional power source, an inverter that converts the output of the source, a step-up transformer that steps up the output of the inverter, and a magnetron energized by the step-up transformer. , 111J of the switching elements of the inverter (Iiif), the rectifier, the RFI, the inverter, the step-up transformer, and 1iii, the drive circuit and the high voltage terminal of the magnetron are placed in a case with substantially the same potential. Store and 1) II
The magnetron and the case are combined into one,
A microwave shielding means is provided between the high voltage terminal of the inI magnetron and the step-up transformer.

The function book Fan Ming has the following functions according to the L structure.

That is, the high-frequency heating device of the present invention has a configuration in which the rectifier, the inverter, the step-up transformer, the drive circuit, and the high-voltage terminal of the magnetron are housed in a case with substantially the same potential, and the magnetron and the case are integrated. , parts that were previously separated can be compactly assembled, allowing for a configuration with less troublesome assembly and wiring. Furthermore, since there are fewer wiring lines, it is possible to reduce the '1 magnetic radiation noise generated by the wiring acting as an antenna. Majko,
By inserting a microwave shielding means between the magnetron's high voltage terminal and the booster lance, it is possible to prevent malfunctions caused by noise from the magnetron due to unnecessary radiation that affects the drive circuit. Since the entire structure is integrated, it is possible to prevent radiation noise from having an adverse effect on communication systems and equipment such as televisions and radios.

EXAMPLE Hereinafter, an example of the high frequency heating device of the present invention will be described with reference to the drawings.

FIG. 2 is a circuit diagram of the high frequency heating device of the present invention, and the fourth
Components corresponding to those in the figures are given the same reference numerals and explanations will be omitted.

In FIG. 2, power from a commercial power supply 1 is sent to a unidirectional power supply (full-wave rectification source) 3 and supplied to an inverter 23. This is to supply high-voltage power to the magnetron 13.

The currents flowing through the transistor 8, the primary winding 23 of the transformer, the resonant capacitor 6, and the magnetron 13 are as shown in FIGS.
dl, and the anode voltage V of the magnetron 13
AK becomes like La(e). This is because the line to the primary and secondary line of the step-up transformer 7 (the quality is as shown in the figure, and the step-up E) - the lance 7 is of leakage type.
This is because the high voltage capacitor 10 is connected in parallel to the magnetron 13. Capacitors 25a, 25b, 25 in FIG.
c, 25d, and choke coils 28a and 26b constitute a power filter section 27, which connects the quotient m' from the inverter 23 to the terminal ([prevents the generation of sound and prevents unnecessary / lQa radiation from flowing through the wiring]. The purpose is to prevent

FIG. 1 shows a cross-sectional view of a high-frequency heating device according to an embodiment of the present invention. Components opposite to those in FIG. 4 are given the same reference numerals. In FIG. 1, a step-up transformer 7, a drive circuit 10, a rectifier circuit 29, and a high-voltage terminal 30 of the magnetron are housed inside a case 28 that is integrated with the magnetron 13, and the potential of the case 28 is at the ground level. There is. By integrating in this manner, a compact high-frequency heating device with fewer wirings is realized, and the structure is such that leakage of +H (T magnetic waves) and fs is prevented.

Punched holes 31°32 for cooling on the wall of the case 28
A noise filter 27 is provided at the Ichihara cord lead-out section to prevent Hl:sound generated through the power cord. The high voltage terminal section 30 of the magnetron has an inductance of 17°18 and a capacitor 1.
A Neussoff router consisting of 4, 15 and 18 is provided to prevent malfunction of the circuit due to electromagnetic waves. Magnetron 17. Heat-generating components such as the step-up transformer 7 are configured to be cooled by a cooling fan 20. In this way, it constitutes a compact high-frequency heating device with less negative effects from electromagnetic noise.
You may also use means to suppress the occurrence by using materials, etc.

Child of invention 1! : As stated above*, according to the invention, the following effects can be obtained.

(1) The structure integrates -L essential parts such as the magnetron and A-voltage transformer, making it a compact high-pressure [J].
Wave heating equipment fi! can provide t.

(2) Since the heat-generating parts are integrated, the cooling configuration is easy, and high-frequency heating/waiting 1L' has high cooling efficiency. can be provided.

(3) Prevent leakage of mixed magnetic waves with an integrated case? Therefore, it is possible to provide a high-frequency heating device that has a large leakage prevention effect and is less likely to generate noise.

(4) Integration reduces wiring and wires, making assembly and wiring easier, and reduces noise generated when the wires act as antennas, making it possible to provide an inexpensive and highly reliable high-frequency heating device.

(5) Since the microwave shielding means is provided between the magnetron and the step-up transformer, it is possible to provide a highly reliable high-frequency heating device fiR with less circuit malfunction due to noise.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a high-frequency heating device in an embodiment of 4-, π-light, Fig. 2 is a circuit diagram of the same device, 3L is a current/'11 dead pressure waveform diagram of each part of the circuit, and Fig. 2 is a circuit diagram of the same device. Figure 4 is the conventional (')
FIG. 5 is a cross-sectional view of the high-frequency heating device. 1...Commercial power supply, 3...Signal Ii direction power supply, 7...
- Step-up transformer, 8... Switching element (transistor), 10... Drive circuit, 23... - Inverter, 27... Noise filter, 28... Case,
30...High voltage terminal. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 7 Me 3 Magne + Ron 3 Theta word hill Sai 1 child / 9 / 415. /〆Haku 2 Figure 3 Figure '7KV

Claims (2)

[Claims] (1) a rectifier that converts a commercial power source into a unidirectional power source; an inverter that converts the output of the unidirectional power source; a step-up transformer that steps up the output of the inverter; and a magnetron energized by the step-up transformer; The rectifying means, the inverter, the step-up transformer, the drive circuit, and the high-voltage terminal of the magnetron are housed in a case having substantially the same potential, and the magnetron and the case are integrated. A high-frequency heating device having a configuration in which microwave shielding means is provided between a high-voltage terminal of the magnetron and the step-up transformer. (2) The high-frequency heating device according to claim 1, wherein a noise filter is provided between the commercial power source and the rectifying means.