JPH01140590A - High frequency heating device - Google Patents

Abstract

PURPOSE:To reduce the cost of a structure and improve its reliability by using a commercial power source voltage-reduced by a resistance and a diode, and inserting a door switch for interruption of a high frequency generator. CONSTITUTION:If power is applied to a high voltage transformer 5, a high voltage is applied to a magnetron 12 to generate a high frequency output. A controller 20 uses the ground side of a commercial power source 1 as a common line to obtain a DC voltage of +5V by means of a resistance 22, a diode 23, etc. In the meanwhile, a DC voltage of about 24V is obtained by means of a resistance 27, a constant voltage diode 28, and an electrolytic capacitor 29. For putting a power relay 18 on, a door switch 14 interlocked with a latch switch 2 to get on-off shall be closed, and a contact 18a shall be closed based on a start signal from a keyboard. If a door 16 is opened, the contact 18a gets off. If this constitution, the power source for the device 20 includes no transformer, thereby the number of parts is reduced, and reliability is improved. Safety is high.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high frequency heating device having a control device such as a microcomputer.

2. Description of the Related Art As shown in FIG. 4, a conventional high-frequency heating device has one line connected to a commercial power source 1 with a latch switch 2 that turns ON and OFF in conjunction with the opening and closing of a door provided at the front of the high-frequency heating device. It is supplied to a lamp 3 that illuminates the interior of the high-frequency heating device, a fan motor 4 for cooling the magnetron 12 that is a source for supplying radio waves to the interior of the high-frequency heating device, and a high-voltage transformer 5 that generates high voltage. There is.

The other line passes through fuse 6 to low voltage transformer 8 in control block 7, and relay 9 to intermittent high frequency heating.
It is supplied to the high voltage transformer 5 through the contact 9a.

When power is applied to the high voltage transformer 5, the high voltage capacitor 1
The voltage is doubled and rectified by the 01 high-voltage diode 11, and a high voltage is supplied to the magnetron 12, which oscillates.

The control block 7 has a control circuit including a microcomputer, and a low voltage transformer 8 supplies low voltage power to the control circuit. The lamp 3 and fan motor 4 are switched on and off by a relay 13. Further, in conjunction with the launch switch 2, a signal from the door switch 14 is input to the control circuit to recognize the opening/closing status of the door.

Problems to be Solved by the Invention However, with the conventional configuration as described above, the commercial power supply side and the secondary side (low voltage side) of the low voltage transformer must be completely separated, so there is no possibility of interruptions on the commercial power supply side. For control, it is necessary to use an OC voltage-driven relay or a triac via a foot coupler, which increases the number of parts, reduces reliability, and becomes a major factor in increasing costs, which significantly increases the unit price of the product. /was.

The present invention solves these conventional problems and provides a high-frequency heating device that has a simple configuration, is inexpensive, and has high reliability.

Means for Solving the Problems The high-frequency heating device of the present invention utilizes a commercial power supply that has been lowered in voltage by direct resistors and diodes as a power source for a control device that performs intermittent heating control, and also uses a magnetron intermittent relay drive coil. A door switch is used to open and close the door.

Further, a triac, which is a semiconductor switching element, is used as a disconnection device for disconnecting and disconnecting the fan motor.

Operation: Therefore, although the high frequency disconnection device of the present invention is a control device having a transformerless configuration, the door switch is interposed in the control of the magnetron disconnection relay, and the control is performed using a plurality of signals, so that the safety is extremely high.

Because it is transformerless, the control device and the commercial power supply side share one power line, so semiconductor switching elements such as triacs can be directly controlled by signals from the control unit without the need for isolation elements such as photo couplers. This makes it possible to have a very simple circuit configuration, improve reliability due to the small number of parts, and provide an inexpensive high-frequency heating device.

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

FIG. 1 is a circuit configuration diagram of the present invention, FIG. 2 is a block diagram of a control device having the same circuit configuration, and FIG. 3 is an external view of the high-frequency heating device in the direction of arrows.

In FIGS. 1 to 3, the power line on one side of the commercial power source 1 is connected to a door 16 provided in the front of the high-frequency heating device 15.
A latch switch 2 that turns ON and OFF in conjunction with the opening and closing of 5.

The other power line is supplied to the high voltage transformer 5 through the fuse 6 and the cathode side of a triac 17, which is a semiconductor switching means that connects and connects the lamp 3 and fan motor 4, and the contact point 18m of a power relay 18 that connects and connects the high frequency. .

When power is applied to the high voltage transformer 5, the high voltage capacitor 1
0. The voltage is doubled and rectified by the high voltage diode 11, and a high voltage is applied to the magnetron 12 to generate a high frequency output.

The high frequency output generated from the magnetron 12 is transmitted through the waveguide 19.
is guided into the heating chamber to heat and cook the object to be heated. The control device 20 uses the ground side of the commercial power supply 1 (the side opposite to the fuse 6) as a common line. A lightning surge absorbing element 21 is attached to the input of the commercial power supply to protect the control device 20. Resistor RA22, diode 23, and resistor R
A DC voltage of +5V is obtained by B24, a constant voltage diode 25, and an electrolytic capacitor 26.

On the other hand, an OC voltage of approximately 24V is obtained by the resistor RC27, voltage regulator diode 828, and electrolytic capacitor 29.

The +5V OC voltage is supplied as a power source to the control unit 30. A microcomputer 31 is disposed in the control unit 30, and displays the time etc. on the liquid crystal display tube 33 according to input information from the keyboard 32, and displays the time etc. on the power relay 18. 0N-OFF
It outputs signals 34 and 35 to cause the

Furthermore, an output signal is also output to a transistor 36 that controls the on/off of the triac 17.

In order to turn on the power relay 18, the door switch 1 is turned 0N-OFF in conjunction with the launch switch 2.
4 is in the closed state, and a start signal is input from the keyboard 32, and based on that signal, the output signal 34 is
, the contact 18g closes only when the signals 835 and 835 are output together (
ON).

If the door 16 is opened or at least one of the signals 34 and 35 is turned OFF, the contact will surely open (
OFF) state. In addition, the intermittent control of the triac 17 is possible because one side of the commercial power supply 1 and one side of the control device 2o have a common power supply line, so the transistor 36 directly controls ON-OF.
Since F control is possible, a circuit with a simple configuration and low cost can be assembled.

If the display of the control device 20 is performed by the liquid crystal display tube 33, the intermittent control of the fan motor 4 and the lamp 3 is performed by the triac 17, and the microcomputer 31 is configured by C-MOS, the power consumption can be extremely reduced.
22. RB24. The power consumption of the RC27 can be suppressed, a small and inexpensive resistor with low power dissipation can be used, and the reliability is also improved since less heat is generated.

Furthermore, the power relay 18 is used to control the insulation of the magnetron 12.
A mechanical relay is used instead of a semiconductor switching element, and the power relay 18 is controlled only by the door switch 14 and a plurality of signals, so it uses a high frequency relay that is extremely safe and reliable. A heating device can be provided.

Effects of the invention (1) The power source for the high-frequency heating device is obtained directly from the commercial power source using resistance diodes, constant voltage diodes, etc., and it has a transformer-less configuration and triac control can be directly controlled, resulting in fewer parts and higher reliability. It is possible to realize an inexpensive circuit configuration.

(2) The control of the power relay uses a mechanical coil relay instead of a semiconductor switching element, and its intermittent control is turned on only by multiple signals from the door switch and microcomputer, ensuring safety and reliability. Extremely sensitive.

(3) Since triacs are used to control lamps and fan motors, the current consumption is lower than when using coil relays, so the power consumption of resistors, diodes, etc. that require low voltage can be suppressed, and the rated power can be reduced. Small elements can be used, and the heat generated by each element can be minimized.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram of the present invention, and FIG. 2 is a circuit configuration diagram of the same circuit thermal device. 1... Commercial power supply, 2... Latch switch, 3... Lamp, 4... Fan motor, 5... High voltage transformer, 6 ... Fuse, 7 ... Control block, 8 ... Low voltage transformer, 9 ... Relay, 1o ... High voltage condenser +)', 11. ...High voltage diode, 1
2... Magnetron, 14... Door switch, 17... Triac, 18...
...Power relay, 20...Control device, 30
...Control unit, al...Microcomputer. Name of agent: Patent attorney Toshio Nakao and 1 other person
2 mouths Figure 4

Claims (1)

[Claims] A heating chamber for storing an object to be heated, a high-frequency oscillation device for heating the object to be heated, a door provided at a front opening of the heating chamber, a door switch means that is turned on and off as the door is opened and closed, and the high-frequency oscillation device It consists of a fan motor that cools the device, a control device that intermittently controls the high-frequency oscillation device, the fan motor, etc., and the control device is a low-voltage section that performs half-wave rectification of the commercial power source and then processes the low voltage through a resistor. One of the low voltage sections is input to a control section powered by the low voltage section, and the other is connected to the high frequency oscillator intermittent relay coil section via the door switch means,
The high-frequency heating device is configured such that the intermittent relay coil is turned on and off by a plurality of signals output from the control section, and a semiconductor switching means is used as the fan motor intermittent means.