JPH0536203U - Microwave oven heater operation mode switching device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a low cost microwave oven operation mode switching device with a simplified control unit. [Composition] In a microwave oven with a heater, which opens and closes a ventilation opening by a damper 2 to switch the operation mode between microwave heating and heater heating, the motor 1 and the opening / closing operation of the damper 2 are controlled in conjunction with the rotation of the motor 1. A damper mechanism A including a damper cam 3 and a damper switch 4 that opens and closes when the cam 3 rotates, and an LSI to which an adjustment current is input when the damper switch 4 is opened and closed.
8 and a control unit B composed of a relay R _Y that operates by the output voltage of the LSI 8 and opens and closes a parallel circuit of the magnetron 9 and the heater 11, and is connected in series to the contact of the relay, and by the rotation of the damper cam 3. An operation mode selector switch 13 for selectively switching between the magnetron 9 and the heater 11 is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an operation mode switching device for a microwave oven that also includes a heater for heating.

[0002]

[Prior Art]

 Conventionally, when microwave-heating food in a microwave oven, in order to prevent water vapor generated from the food from condensing the interior of the oven, a ventilation port opened on the partition wall between the oven and the equipment room. The air used to cool the magnetron is sent to the inside of the store.

On the other hand, recently, some microwave ovens include a microwave oven with a heater that can heat food with a heater. When heating with a heater in this microwave oven, if the air is blown into the refrigerator, the rate of rise in temperature inside the refrigerator will decrease, and the ventilation to the refrigerator will be an obstacle. Therefore, when the heater is heated, it is customary to block the ventilation port with a damper to block the air flow into the refrigerator.

FIG. 2 shows a schematic circuit diagram of a conventional microwave oven with a heater. Reference symbol A denotes a damper mechanism, a motor 1, a damper cam 3 that rotates in conjunction with the rotation of the motor 1 and that rotates with the damper 2, a damper switch 4 that opens and closes when the damper cam 3 rotates, and It comprises a resistor 5 connected in parallel to the damper switch 4, a check switch 6 for checking whether the damper 2 opens or closes the ventilation port, and a pole changeover switch 7 for forward / reverse rotation of the motor 1.

Reference numeral B denotes a control unit, which closes the check switch 6 so that a small current flows through the resistor 5 when the damper switch 4 is OFF (damper 2 is open) and when the damper switch 4 is ON (damper). (2 is a closed state) The LSI 8 to which a large current with the resistor 5 short-circuited is input, and the magnitude of the input current is determined by this LSI 8, and the output of the small current input determines the oscillation current of the magnetron 9 for microwave heating. A microwave relay R _Y1 that closes the circuit of the high-voltage transformer primary winding 10 that is the source (the heater relay R _Y2 is OFF), and a heater that closes the circuit of the heater 11 for heating the heater by the output when a large current is input. Relay relays R _Y2 and (microwave relay R _Y1 OFF), microwave heating, heater heating operation modes CT ₁ , C The display unit 12 displays from T ₂ via the LSI 8.

Table 1 shows the operation modes described above.

[Table 1]

[0007]

[Problems to be solved by the device]

As described above, in the conventional microwave oven with a heater, the microwave heating and heater heating operation modes are performed by two separate relays R _Y1 and R _Y2 , respectively. There was a problem that the size of the car became large and the cost was high.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an operation mode switching device for a microwave oven with a heater that simplifies a control unit and is inexpensive.

[0009]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention relates to a microwave oven with a heater in which a ventilation port is opened and closed by a damper to switch the operation mode between microwave heating and heater heating. A damper mechanism consisting of a damper cam that regulates the opening / closing operation of the damper and a damper switch that opens / closes when the cam rotates, an LSI to which an adjustment current for opening / closing the damper switch is input, and the output of the LSI. Control unit consisting of a relay that operates by voltage and opens and closes the parallel circuit of the magnetron and heater, and is connected in series to the contact of the relay, and operates to selectively switch between the magnetron and heater by rotating the damper cam. And a mode changeover switch.

[0010]

[Action]

 In the microwave heating operation mode, when the damper cam is turned to open the damper, the damper switch is turned off and the operation mode switching switch is switched to the magnetron circuit side. In addition, the parallel circuit of the magnetron and the heater is turned on by the relay that is turned on by the output from the LSI to which the current from the damper switch is input, and the ventilation opening is opened to perform microwave heating.

In the heater heating operation mode, when the damper is closed by the rotation of the cam, the damper switch is turned on and the operation mode switch is switched to the heater circuit side. Moreover, the parallel circuit of the magnetron and the heater is turned on by the relay that is turned on by the output from the LSI to which the current from the damper switch is input, and the ventilation port is closed to heat the heater.

[0012]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. The same parts as those in the conventional example are designated by the same reference numerals. The present invention is reduced in number of relays by one compared with the conventional example, and is provided with an operation mode changeover switch for switching between the microwave side and the heater side by rotating the damper cam instead of the reduced relay. Since the other parts are the same, detailed description will be omitted.

The damper mechanism A includes a motor 1, a damper 2, a damper cam 3, a damper switch 4 for opening and closing a part of a resistor 5, a check switch 6, a pole conversion switch 7 and the constituent elements of the present invention. It is composed of an operating mote changeover switch 13 for selectively switching between a circuit on the side of the high voltage transformer primary winding 10 serving as an oscillation power source of the magnetron 9 and a circuit on the side of the heater 11 by the rotation of the damper cam 3. Therefore, when the damper 2 is in the state where the ventilation port is opened by the rotation of the damper cam 3, the damper switch 4 is turned off, and the switching piece of the operation mode changeover switch 13 is switched to the high voltage transformer primary winding 10 side. On the other hand, when the damper 2 closes the ventilation port, the damper switch 4 is turned on, and the switching contact piece of the changeover switch 13 is changed over to the heater 11 side.

The control unit B includes an LSI 8 to which a current accompanying opening / closing of the damper switch 4 is input, and a relay R _Y which opens / closes a parallel circuit of the high voltage transformer primary winding 10 and the heater 11 by the output of the LSI 8. .. In addition, 12 is an operation mode display.

Table 2 shows the above operation modes.

[Table 2]

[0016]

[Effect of the device]

 According to the present invention, the number of conventional relays is reduced by one, and the operating mode changeover switch, which is cheaper than the relays, is provided in the damper mechanism instead of the conventional relays, so that the control unit board can be easily and miniaturized. The cost of the microwave oven with a heater can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic circuit diagram showing an embodiment of the present invention.

FIG. 2 is a schematic circuit diagram of a conventional example.

[Explanation of symbols]

A damper mechanism 2 damper 3 damper cam 4 damper switch 13 operation mode selector switch B control unit 8 LSI _RY relay 9 magnetron 10 high voltage transformer primary winding 11 heater

Claims (1)

[Scope of utility model registration request] 1. A microwave oven with a heater that opens and closes a ventilation opening by a damper to switch between microwave heating mode and heater heating mode. A motor and a damper cam that controls the opening and closing operation of the damper in conjunction with the rotation of the motor. And a damper mechanism including a damper switch that opens and closes when the cam rotates, an LSI to which an adjustment current is input by opening and closing the damper switch, and an output voltage of the LSI to operate, and a parallel circuit of a magnetron and a heater. A control unit consisting of a relay for opening and closing the relay, and an operation mode selector switch that is connected in series to the contact of the relay and selectively switches between the magnetron and the heater by rotating the damper cam. Microwave oven operation mode switching device.