JPH023043Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a microwave oven equipped with an oven function, and particularly to a microwave oven having a function of exchanging the air inside the heating chamber with outside air before heating the food.

[Technical background of the invention]

Conventionally, as a microwave oven having an oven function, there are, for example, those shown in FIG. 1 and 2.
In FIG. 1, reference numeral 1 denotes a case that houses the main body of the microwave oven, and exhaust ports 2 and 3 are provided on the wall of this case 1. A heating chamber 4 for storing the object to be heated A is provided in the case 1, and on the wall of the heating chamber 4, an engaging protrusion 5, an intake port 6, and an exhaust port 7 are provided for constructing cooking shelves in multiple stages. and is provided. Furthermore, a rotatable turntable 8 is arranged on the floor of the heating chamber 4, and a heated object A inserted through a door 9 provided on the front surface of the heating chamber 4 is placed thereon. Heat item A evenly. A microwave source 10 such as a magnetron is provided outside the heating chamber 4, and the microwaves output from the microwave source 10 are supplied into the heating chamber 4 directly or via a waveguide or the like to heat the object A. do. A cooling fan 11 is disposed near the microwave source 10, and after cooling the microwave source 10 with air blown out from the cooling fan 11, the air is discharged from the exhaust port 2. Upper heater 1 is installed on the ceiling of heating chamber 4.
2. Lower heaters 13 are provided on each floor,
It has a so-called oven function in which the object to be heated A is directly heated by these heaters 12 and 13. Further, a gas sensor 14 is provided in the blowing path of the exhaust port 7 of the heating chamber 4 . This gas sensor 14 detects gas generated when the object to be heated A is heated by microwaves, and outputs a detection signal. Then, based on this detection signal, a control device (to be described later) determines whether the cooking of the heated object A is finished, and
Stop heating. Here, before heating the object to be heated A, outside air is introduced into the heating chamber 4 from the intake port 6 using the cooling fan 11, and the air inside the heating chamber 4 is passed through the exhaust ports 7 and 3 to the outside. It has a so-called refresh function that replaces the air in the heating chamber 4 by discharging the air to the heating chamber 4.

FIG. 2 is a schematic configuration diagram of an electric circuit installed in the microwave oven of FIG. 1. In Figure 2, 20
is a power plug, and the alternating current input from this power plug 20 is switched to the 21a or 21b side by the switching relay contact 21, and is sent to the upper heater 12 and lower heater 13 connected in parallel, or to the high voltage transformer. 22 on the primary side. Here, the series loop on the 21b side of the power plug 20, the upper and lower heaters 12 and 13, and the switching relay contact 21 includes a fuse 23 for overcurrent protection, a door switch 24 that turns off and on according to the opening and closing of the door 8, 2
5. A relay switch 26 for controlling energization of the microwave source 10, a relay contact 27 for turning on the power, and a thermal switch 28 for preventing overheating are connected in series. In addition, an interior light 29 is connected in parallel between the fuse 23 and the power supply relay contact 27.
However, a drive motor 31 for the turntable 8 and a drive motor 32 for the cooling fan 11 are connected in parallel between the connection point between the door switches 24 and 25 and the thermal switch 28 via a relay contact 30, respectively. In addition, a short switch 33 is connected in parallel with the drive motors 31 and 32 and a relay contact 30, which turns off and on in conjunction with the on and off of the door switches 24 and 25, and a relay contact 34 for turning on and off the lower heater is connected in series with the lower heater 13. , are connected respectively.

On the other hand, the microwave source 10 is connected to the secondary side of the high-voltage transformer 22 via a high-voltage capacitor 40, a high-voltage rectifier 41, etc., and the alternating current on the secondary side of the high-voltage transformer 22 is smoothed by the high-voltage capacitor 40, and the high-voltage rectifier When the current is converted into direct current at 41 and applied to the microwave source 10, the microwave source 10 is activated and outputs microwaves.

Further, a control power transformer 42 is connected in parallel between the fuse 23 and the thermal switch 28, and a control voltage is applied to the control device 43 via the transformer 42. The control device 43 includes a microprocessor with calculation, storage, and control functions, a keyboard as an input device, a driver as an output device, etc., and controls the relay contacts 21, 26, 27 according to a program stored in advance in the microprocessor. , 30, etc. are turned on and off.

FIG. 3 is an explanatory diagram of the operation of FIGS. 1 and 2.

First, the object to be heated A is placed on the turntable 8 in the heating chamber 4, and then the door 9 is closed. In conjunction with this, the door switches 24 and 25 are turned on, and the exit switch 33 is turned off. Here, the shot switch 33 is provided so that when the door switches 24 and 25 are out of order,
This is to ensure the safety of the device by turning on the short switch 33 and blowing out the fuse 23.

Next, a keyboard provided on the control device 43 is used to select between microwave cooking or oven cooking using the heaters 12 and 13. Here, when microwave cooking is selected, the switching relay contact 21 enters the 21a side. To start cooking, press the cooking start key on the keyboard at T ₁ in Figure 3, and relay contacts 27 and 30 turn on.
The turntable drive motor 31 and the cooling fan drive motor 32 are energized to drive the turntable 8.
And the cooling fan 11 rotates. Note that since the relay contact 26 is in the off state, the high voltage transformer 22 is not energized, and therefore the microwave source 10 is not operating. The cooling fan 11 is driven by the control device 43 until time _T2 . and cooling fan 1
1 from the air intake port 6 to the heating chamber 4 in FIG.
Since the air inside the heating chamber 4 is discharged to the outside through the exhaust ports 7 and 3, the air inside the heating chamber 4 is replaced with fresh air (so-called refreshment).
be done. Here, the rotation time of the cooling fan 11 T ₀
(=T ₂ - _{T 1} ) is set to, for example, about 16 seconds, and when this time T ₀ has elapsed, the control device 43 turns on the relay contact 26 to energize the microwave source 10, and also drives the cooling fan. The rotation of the motor 32 is switched to the opposite direction. When the microwave source 10 is energized, microwaves are outputted from the microwave source 10 and supplied to the heating chamber 4, so that the object A is heated and cooked. At this time, the microwave source 10
is cooled by a cooling fan 11, and the cooled air is discharged to the outside through an exhaust port 2. Also,
Gas generated from the heated object A during heating comes into contact with the gas sensor 14 when being discharged to the outside via the exhaust ports 7 and 3. When the amount of gas detected by the gas sensor 14 exceeds the set value, the control device 43 turns off the relay contact 27 at time _T3 in FIG. The wave source 10, the turntable drive motor 31, and the cooling fan drive motor 32 stop, and the microwave cooking ends.

On the other hand, in order to perform oven cooking, a cooking shelf is installed on the engagement convex portion 5 of the heating chamber 4, and after placing the object to be heated A on the cooking shelf, the door 9 is closed. Next, when oven cooking is selected using the keyboard provided in the control device 43, the switching relay contact 21 enters the 21b side. Then, when you press the cooking start key on the keyboard, relay contacts 27, 26,
34 is turned on, the upper heater 12 and the lower heater 13 are energized, and the object to be heated A is cooked. If only the upper heater 12 or the lower heater 13 is used here, only the relay contact 26 or 34 may be turned on by the control device. Also, when cooking in an oven, the heaters 12 and 13 are turned on after rotating the cooling fan 11 to replace the air in the heating chamber 4 with outside air for a predetermined time T ₀ (see Figure 3) from the start of cooking. It is also possible to control it so that it is energized.

[Problems with background technology]

However, in the case of conventional microwave ovens,
The time T ₀ for exchanging the air in the heating chamber 4 after the start of cooking is about 16 seconds, and as the cooking time has been shortened, there has been a desire to shorten this time T ₀ . In order to shorten this time T ₀ , it is conceivable to increase the air volume by increasing the size of the cooling fan 11, but this has the disadvantage that the microwave oven itself becomes larger. Also, when cooking in the oven,
A cooking shelf is installed on the engagement convex portion 5 of the heating chamber 4, and the object to be heated A is placed on the cooking shelf and heated by the heaters 12 and 13, so that the cooking shelf can be arranged in multiple stages. When the object to be heated A was heated in this way, there was a drawback that uneven heating occurred.

[Purpose of invention]

The present invention was made to eliminate the above-mentioned drawbacks of the conventional technology, and provides a microwave oven that eliminates uneven heating during oven cooking and shortens the time for replacing the air in the heating chamber at the start of cooking. The purpose is to

[Summary of the idea]

a heating chamber that stores an object to be heated; a microwave source that supplies microwaves for heating the object into the heating chamber; a cooling fan that cools the microwave source; and a cooling fan that is switched between the microwave source and the heated object. The apparatus includes a heater for heating an object, and a gas sensor that detects gas generated from the object to be heated during heating and outputs a detection signal, and determines that cooking of the object to be heated is completed based on the detection signal of the gas sensor. In the microwave oven, the heating of the object to be heated is stopped based on the judgment, a heater and a fan for hot air provided outside the heating chamber to supply hot air into the heating chamber, and for introducing outside air into the heating chamber. an air inlet that can be opened and closed, and the air inlet is opened only for a predetermined period of time from the start of cooking to drive the cooling fan and the hot air fan to replace the air in the heating chamber with outside air, and then the microwave source or the heater is heated. The invention is characterized in that it is provided with a control device that operates the control device.

[Example of idea]

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1, 2 and 5. In FIGS. 4 and 5, the same elements as those in FIGS. 1 to 3 are given the same reference numerals.

4. FIG. 4 1 is a longitudinal cross-sectional view with a part of the internal mechanism of the microwave oven omitted, and FIG. 2 is a cross-sectional view taken along the line -- in FIG. 1. The difference between this microwave oven and the one in FIG. 1 is that an intake port 50 for taking in outside air is provided on the wall of the case 1, and a damper 51 is installed between the case 1 and the heating chamber 4 corresponding to the intake port 50 for hot air. Juan 52 and
An intake port 53 is provided on the inner wall of the heating chamber 4, respectively. Then, by opening the damper 51 and rotating the hot air fan 52, outside air is taken in from the intake port 50 and passed through the intake port 53 into the heating chamber 5.
Supply inside.

FIG. 5 is a schematic diagram of an electric circuit installed in the microwave oven of FIG. 4. This electric circuit differs from the one in Figure 2 in that a series circuit consisting of a relay contact that turns on and off the hot air heater 60 is connected in parallel with the lower heater 13 and relay contact 34, and that the hot air fan is driven. A series circuit consisting of a motor 62 and a relay contact 63 that turns on and off the motor 62 is connected to the turntable drive motor 3.
1. A series circuit consisting of a damper drive motor 64 and a relay contact 65 that turns on and off the motor 64 is connected in parallel to the cooling fan drive motor 32 and the relay contact 30, and is connected to the connection point between the door switches 24 and 25. This is because it is connected between the relay contact 27 and the relay contact 27. and relay contacts 61,6
3 and 65 are turned on by the control device 43, respectively.
Controlled off. The drive motor 60 is installed near the hot air fan 52 shown in FIG.

In the above configuration, when microwave cooking is selected using the keyboard provided in the control device 43 and the cooking start key is pressed, the relay contacts 27, 30, 63, and 64 are turned on by the control device 43, and the turntable The drive motor 31, the cooling fan drive motor 32, the hot air fan drive motor 62, and the damper drive motor 64 are energized, and the damper 51 is opened to open the turntable 8 and the cooling fan 1.
1 and the hot air fan 52 rotate. Then, a cooling fan 11 and a hot air fan 5 are installed in the heating chamber 4.
2 takes in outside air and the air in the heating chamber 4 is discharged to the outside through the exhaust ports 7 and 3, so that the air in the heating chamber 4 is rapidly replaced.
Here, for example, assuming that the wind pressure of the cooling fan 11 and the wind pressure of the hot air fan 52 are equal, it is possible to replace the air in the heating chamber 4 in 1/2T ₀ time compared to the conventional one. becomes. When the air exchange is completed, the control device 43 turns off the relay contacts 63 and 65, closes the damper 52 and stops the hot air fan 62, and turns on the relay contact 26 to activate the microwave source 10. The object to be heated A is then heated. In this way, in this embodiment, the time for exchanging the air in the heating chamber 4 is shortened compared to the conventional one, so that microwave cooking can be shortened.

Further, when oven cooking is selected using the keyboard provided in the control device 43, the relay contact 21 for switching enters the 21b side, and when the cooking start key is then pressed, the control device 43 causes the relay contacts 26, 27 to enter. , 34, 61, and 63 are turned on, and the upper and lower heaters 12, 13 are energized, and
Hot air fan drive motor 62 and heater 60
Since the heating chamber 4 is also energized, the inside of the heating chamber 4 is heated by the heat from the upper and lower heaters 12 and 13 and the hot air from the hot air heater 60 and the fan 52. Since the heat from the upper and lower heaters 12 and 13 is agitated by the hot air, the inside of the heating chamber 4 is heated uniformly, and uneven heating of the heated object A as in the conventional method can be easily prevented. It becomes possible to shorten the time. In addition, in this oven cooking as well, the heater 12,
The air in the heating chamber 4 may be controlled to be replaced before turning on the heating chambers 13 and 60.

[Effect of idea]

As explained above, according to the present invention, since the hot air heater and fan are provided, not only can heating unevenness in oven cooking be eliminated, but also the hot air fan is used together with the cooling fan before heating the object to be heated. Since the air in the heating chamber is exchanged with outside air using the air conditioner, the time for exchanging the air in the heating chamber can be shortened, and therefore the cooking time can be shortened.

[Brief explanation of the drawing]

1, 2 and 3 are explanatory diagrams of a conventional microwave oven, in which FIG. 1 is a vertical sectional view of the microwave oven, FIG.
The figure is an electric circuit diagram mounted on the microwave oven in Figure 1, Figure 3 is an explanation diagram of the operation of Figure 2, and Figure 4 is 1 and 2.
4 and 5 are explanatory diagrams of a microwave oven according to an embodiment of the present invention, in which FIG. 4 1 is a longitudinal sectional view of the microwave oven, FIG.
The figure is an electric circuit diagram mounted on the microwave oven of FIG. 4. 1... Case, 4... Heating chamber, 8... Turntable, 9... Door, 12... Upper heater, 13...
Lower heater, 10...Microwave source, 11...Cooling fan, 14...Gas sensor, 21...Switching relay contact, 22...High voltage transformer, 24, 25...
...Door switch, 26, 27, 30, 33, 3
4, 61, 63, 65...Relay contact, 31...
Turntable drive motor, 32... Cooling fan drive motor, 41... High voltage rectifier, 42... Control power supply transformer, 43... Control device, 50, 53
...Intake port, 51...Damper, 52...Hot air fan, 60...Hot air heater, 62...Hot air fan drive motor, 64...Damper drive motor.

Claims (1)

[Claims for Utility Model Registration] A heating chamber that stores an object to be heated, a microwave source that supplies microwaves for heating the object into the heating chamber, a cooling fan that cools the microwave source, and a cooling fan that cools the microwave source. A heater that is switched with a microwave source to heat the object to be heated, and a gas sensor that detects gas generated from the object to be heated during heating and outputs a detection signal, based on the detection signal of the gas sensor. In the microwave oven, the heating of the object to be heated is stopped upon determining the completion of cooking of the object to be heated, comprising: a heater and a fan for hot air provided outside the heating chamber to supply hot air into the heating chamber; an openable and closable intake port for introducing into the heating chamber;
and a control device that opens the intake port only for a predetermined period of time from the start of cooking, drives the cooling fan and the hot air fan, replaces the air in the heating chamber with outside air, and then operates the microwave source or the heater. A microwave oven characterized by: