JP3257236B2 - Cooking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating cooker provided with a heating means using a resistance heating element such as a nichrome heater and an induction heating means.

[0002]

2. Description of the Related Art In recent years, an induction heating coil for generating a high-frequency magnetic field and inductively heating a load pan, and a resistance heating element such as a nichrome heater for generating a current by supplying a commercial frequency current to the lower portion of the same top plate, or an induction heating coil or the like. A heating cooker in which a heating chamber is provided below a heating coil and a resistance heating element such as a sheath heater is disposed therein has been developed.

[0003] A conventional heating cooker will be described below. FIG. 10 shows a conventional built-in type heating cooker equipped with two heating burners for induction heating, one heating burner using a normal resistance heating element, and a heating chamber equipped with a resistance heating element. . In FIG. 6, the main body is divided into an upper unit 1 and a lower unit 2. The upper unit 1 is covered with an upper case 3 made of an iron plate and a top plate 4 made of ceramic, in which a heating coil 5a and a heating coil 5b for induction heating and a resistance heating for heating by passing a current of a commercial frequency are supplied. Is disposed below the top plate 4 so as to face the top plate 4. The upper cooling fan 8 is provided on the near side of the bottom surface of the upper case 3 together with the intake port provided near the lower part thereof, and a plurality of exhaust ports 9 are provided on the rear upper surface of the upper case 3. An opening 2 is provided at the rear bottom surface of the upper case 3.
5 are provided.

The lower unit 2 is covered with a lower case 6 made of an iron plate. A lower cooling fan 10 is provided inside the lower case 6 near the intake port 11, and is a component of an inverter for supplying a high-frequency current to the heating coil 5b. A cooling fin 12 on which a transistor is mounted, and a control board 1 on which control components are mounted
3 and a main board 14 on which high-current components such as a resonance capacitor and a rectifier are mainly mounted are provided between the lower cooling fan 10 and the exhaust port 26.

Similarly, a cooling fin 15, which is a component of an inverter for supplying a high-frequency current to the heating coil 5a,
The control board 16 and a main board (not shown) are provided between the lower cooling fan 10 and the exhaust port 26. The power supply board 17 is a printed wiring board on which a filter coil, a drive circuit of the lower cooling fan 10 and a drive circuit of the upper cooling fan 8 are mounted.

A heating unit 18 is provided in the lower unit 2, and a sheath heater is provided in an upper portion of the heating unit 18 for heating by supplying a current of a commercial power supply frequency. The power switch 19 is provided above the operation unit 21 in which an on / off key, a heating adjustment key, and the like are arranged, along with the display unit 20. The connecting wires connecting the parts of the lower unit 2 and the upper unit 1 are collectively passed through the tube 22, and the electric wire through which the heating coil current flows is connected to the terminal block 23 when the unit is installed, and the current supply line to the nichrome heater 7 is provided. And other signal lines are connected by a connector 24 near the terminal block 23 when the unit is installed.

[0007] The operation of the heating cooker configured as described above will be described below. First, when the power switch 19 is turned on and an input key provided on the operation unit 21 is pressed to operate one of the heating units, the cooling fan 1 is turned on.
0 motor rotates. As a result, external air is sucked in from the air inlet 11 and the cooling fins 12 and 15 and the control board 1
The electronic components mounted on the components 3, 16, the inverter board 14, the power supply board 17, and the like are cooled. The exhaust air after cooling the lower unit 2 is exhausted from the exhaust port 26, and is discharged to the outside from the exhaust port 9 via the opening 25 provided on the bottom surface of the upper case 3.

In the upper unit 1, a cooling fan 8 is provided together with an intake port at the lower part thereof, so that cooling air is sent to the heating coil 5a and the heating coil 5b to be cooled, and the cooled cooling air is discharged from the exhaust port 9. Is done. The high-frequency current generated by the components of the inverter board 14 of the lower unit 2 and the heating coil 5b flows through a connection line passing through a terminal block 23 fixed to the upper part of the lower unit case 6. The same applies to the high-frequency current flowing through the heating coil 5a. The commercial frequency current supplied from the power supply board 17 and flowing to the nichrome heater 7 and other small signals flow through the connection line passing through the connector 24.

The nichrome heater 7 and the heater of the heating chamber 18 can be switched by a key operation of the operation unit 21, and this switching is performed by a relay provided on the power supply board 17.

[0010]

However, in the above-mentioned conventional configuration, a high-frequency generating section such as a cooling fin 12 for cooling the inverter board 14, the control board 13 and the transistor; a low-frequency power section such as a power board 17; Since the drive unit is arranged in the lower unit case 6, the number of connection lines for connecting the upper and lower units increases, the cost of wiring components increases, and the work of connecting a wire through which a large current flows at the terminal block 23 during installation is required. Occurs and overheating may occur if a connection failure occurs. In addition, since the electric components are concentrated on the lower unit case 6, the weight of the lower unit 2 increases, and it is necessary to provide a mounting table for mounting the lower unit. There is a problem that it is difficult to replace the heating chamber 18 which is easily contaminated, has a high degree of wear, and has a short life.

The present invention solves the above-mentioned conventional problems, in which the frequency converter and the heating element control means are provided in the same housing to reduce the size of the equipment, reduce the number of connecting wires between the upper unit and the lower unit, and perform installation work. It is an object of the present invention to provide a simple induction heating cooker. However, when the frequency converter and the heating element control means are provided in the same housing to reduce the size of the device, there arises a problem that the temperature of electronic components in the device increases due to the influence of heat generated by the resistance heating element.

A first object of the present invention is to immediately turn off the power switch or stop driving both the frequency converter and the resistance heating element, and immediately after the residual heat of the resistance heating element, the components inside the machine body overshoot in temperature. In this case, the cooling fan is operated to protect the components when there is a risk of damage.

A second object of the present invention is to further suppress the overshoot temperature more reliably than the first object and to prevent the operation time of the cooling fan from being unnecessarily long.

A third object of the present invention is to prevent a user from erroneously recognizing a protection function added when achieving the first object as a malfunction of a device.

A fourth object of the present invention, in addition to the above-mentioned second object, is to operate the frequency converter and the resistive heating element immediately after turning off the power switch or stopping both the driving of the resistance heating element to prevent a temperature rise. It is to reduce the operation time of a cooling fan as much as possible.

According to a fifth object of the present invention, in addition to the second object, immediately after the power switch is turned off or the driving of both the frequency converter and the resistance heating element is stopped, the operation is continued to prevent a temperature rise. An object of the present invention is to reduce the chance of operating a cooling fan as much as possible.

According to a sixth object of the present invention, in addition to the second object, immediately after the power switch is turned off or the driving of both the frequency converter and the resistance heating element is stopped, the operation is continued to prevent a temperature rise. The operation time of the cooling fan is to be constant.

A seventh object of the present invention, in addition to the second object, is to provide an operation opportunity of a cooling fan to be continuously operated immediately after turning off a power switch or stopping both driving of a frequency converter and a resistance heating element. Is to reduce as much as possible.

[0019]

Means for Solving the Problems In order to achieve the first object, a first means of the present invention comprises a heating coil,
A frequency converter that supplies a high-frequency current to the heating coil, a heating element that generates heat by passing a current of a commercial frequency, a heating element control unit that controls energization of the heating element, and a cooling fan that cools electrical components. A power switch that switches connection and cutoff of the frequency converter or the heating element to or from a commercial power supply, a motor of the cooling fan connected to a commercial power supply of the power switch, and depending on a temperature of the heating element. A temperature detecting means for detecting a temperature of a changing portion and outputting a predetermined signal on condition that the temperature exceeds at least a predetermined temperature, and according to a state of an output signal of the temperature detecting means at a predetermined time. A storage unit for storing and outputting a predetermined output signal, wherein at least the storage unit outputs the predetermined signal,
Alternatively, the present invention provides a heating cooker configured to drive the motor driving means of the cooling fan when any one of a state in which the frequency conversion device is driven and a state in which the heating element is driven occur.

In order to achieve the second object, the second means of the present invention includes a timer means in addition to the first means, and outputs a predetermined signal output from the storage means. A heating cooker whose period is set by the timer means is provided.

[0021] The third aspect of the present invention in order to achieve the third object, in addition to the first means, not driven with at least frequency converter heating element together, the storage means reaches a predetermined Provided is a heating cooker provided with a display device that outputs an output signal and displays or notifies when a cooling fan is in an operating state.

In order to achieve the fourth object, the fourth means of the present invention, in addition to the second means, starts accumulating time in relation to the timing at which the driving of the heating element is stopped. Timer means, and storage means for storing the output state of the temperature detection means in relation to the timing at which the driving of the heating element is stopped, driving the motor driving means based on the storage contents of the storage means, Provided is a heating cooker configured to prohibit the driving of the motor driving means based on the contents stored in the storage means when a time-up signal is output after a predetermined time elapses after the means starts accumulating time.

In order to achieve the fifth object, the fifth means of the present invention, in addition to the second means, starts accumulating time in relation to the timing at which the driving of the heating element is stopped. Timer means, and storage means for storing the output state of the temperature detection means in relation to the timing at which both the heating element and the frequency converter are stopped driving, the motor drive means based on the storage contents of the storage means When a predetermined time has elapsed after the timer means has started to accumulate time and the timer means outputs a time-up signal, the heating cooker is configured to prohibit the driving of the motor drive means based on the contents stored in the storage means. provide.

[0024] Then the sixth sixth aspect of the present invention to achieve the purpose of, in addition to the second means, the time in relation to the timing of the heating element and the frequency converter are both driven stop Timer means for initiating the integration of, and storage means for storing the output state of the temperature detection means in relation to the timing at which the heating element is stopped, and the motor drive means based on the storage contents of the storage means. When a predetermined time has elapsed after the timer means has started to accumulate time and the timer means outputs a time-up signal, the heating cooker is configured to prohibit the driving of the motor drive means based on the contents stored in the storage means. provide.

In order to achieve the seventh object, the seventh means of the present invention is characterized in that, in addition to the second means, a time related to the timing at which both the heating element and the frequency conversion device are stopped from driving. Timer means for initiating the integration of, and storage means for storing the output state of the temperature detection means in relation to the timing at which the heating element and the frequency converter are both driven to stop, and the storage contents of the storage means And driving the motor driving means based on the contents stored in the storage means when the timer means starts to accumulate time and outputs a time-up signal after a predetermined time has elapsed. A heating cooker is provided.

[0026]

[Action] by the first means, the state the frequency converter is driven, or because the heating element drives the motor driving means of the cooling fan if the state to be driven, is energized to the heating element or heating coil When cooling, the electronic components of the heating element control means or the heating coil and the frequency converter are cooled by taking in air from the outside, and the heat received from the heating element and the heat generated by the heat generating components are discharged from the housing to the outside to remove the components. Temperature rise can be suppressed.On the other hand, even if the power switch is turned off, even if the power switch is turned on, the cooling fan stops if all of the above heating sources are turned off, so there is less opportunity to operate the cooling fan. it can.

Further, an output at a predetermined time of temperature detecting means for detecting a temperature of a portion which changes depending on the temperature of the heating element and outputting a predetermined signal on condition that the temperature exceeds at least a predetermined temperature. A storage unit for storing the content of the signal and outputting a signal in accordance with the stored content,
At least when a state in which the storage means outputs a predetermined output signal occurs, the motor drive means of the cooling fan connected to the commercial power supply side of the power switch is driven, so that the temperature of the portion that changes depending on the temperature of the heating element is changed. At a given time,
If the temperature exceeds the predetermined temperature, the cooling fan can be continuously operated thereafter.

Therefore, even if the power switch is turned off or the power switch is turned on and the power supply to both the heating element and the frequency converter is stopped, at a predetermined time,
For example, when the power switch is turned off, when the heating element and the frequency conversion device are both de-energized, or when the energization of the heating element is stopped, etc., the atmosphere or the temperature of the component detected by the temperature detecting means is not changed. If the temperature exceeds the predetermined temperature, the cooling fan can be automatically operated continuously until the temperature detected by the temperature detecting means decreases. Therefore, even if the power switch is turned off when the heating element with a large heat capacity is at a high temperature, or if both the heating element and the frequency converter are de-energized, the residual heat from the heating element or the components around the heating element continues to the outside. And exhaust, thereby preventing thermal destruction of the electronic component due to overshooting of the temperature of the electronic component, which occurs immediately after the cooling fan stops.

Further, since the output state of the temperature detecting means at a predetermined time is stored and the motor driving means is driven according to the state, it is possible to ignore the predetermined output state of the temperature detecting means at times other than the predetermined time. After the power switch is turned off, the heating element and the frequency converter are stopped, and the driving of the cooling fan is stopped, the temperature detected by the temperature detecting means overshoots due to the stoppage of the fan motor. As a result, the output state of the temperature detection means changes beyond a predetermined temperature, and the cooling fan motor once stopped starts to operate for a while while the user does nothing, causing a state giving an unnatural feeling to the user. Can be eliminated.

After the power switch is turned off or the heating element and the frequency converter are both stopped in the first means by the second means, the operation time of the cooling fan by the operation of the storage means is as follows. Since it is defined by the timer means, it is possible to reliably prevent the parts from being destroyed due to the overshoot of the temperature due to the residual heat of the heating element, and to keep the cooling fan from operating longer than necessary.

According to the third means, at least the frequency converter and the heating element are not driven at the same time, and the storage means outputs a predetermined output signal to display or inform when the cooling fan operates. In the first means, the cooling fan may operate even after the power switch is turned off or the power supply to both the heating element and the frequency conversion device is stopped in such a case. The cause can be known from the display device.

The fourth means drives the motor driving means based on the contents stored in the storage means for storing the output state of the temperature detecting means in relation to the timing at which the driving of the heating element is stopped. At the time when the heating element is stopped or immediately before, immediately after, or at a time set in relation to that time, if the temperature detected by the temperature detecting means exceeds a predetermined temperature, the output of the temperature detecting means becomes a predetermined state. ,
For example, the state is “Lo”, and the storage means
The Lo "state is stored, the motor driving means is driven, and even if the power switch is turned off or the power switch is turned on and the heating element and the frequency converter are both de-energized, the cooling fan is continuously or very little. Therefore, after the cooling fan stops, the output state of the temperature detecting means changes from "Lo" to "HI" for a while due to the overshoot of the detected temperature. Thus, there is no unnatural operation such that the cooling fan motor starts to operate for a while (for example, 10 seconds) after the cooling fan is stopped and the user does nothing.

When the timer means for starting the accumulation of time in relation to the timing when the driving of the heating element is stopped is started to output the time-up signal after a lapse of a predetermined time after the start of the accumulation of the time, the contents of the storage means are stored. Since the driving of the motor driving means based on the above is prohibited, when a predetermined time elapses after the driving of the heating element is stopped, the power switch is turned off or both the heating element and the frequency converter are stopped and the operation is continued. The operation of the cooling fan stops.

When the temperature detected by the temperature detecting means exceeds a predetermined temperature, only the heating element is stopped, and when the frequency converter is not stopped, the output signal of the temperature detecting means is changed to a predetermined output state, for example. The state becomes "Lo" and the storage means stores it, and attempts to drive the motor drive means. However, since the frequency conversion device is not stopped, the cooling fan motor is driven regardless of the output state of the storage means. On the other hand, the timer means starts the measurement at or at the time when the heating element is stopped, so that the drive of the motor driving means by the storage means is stopped after a predetermined time has elapsed.

That is, if the use of the frequency converter continues after the heating element is stopped, the time set by the timer means and the time from when the heating element is stopped until the operation of the frequency conversion apparatus is stopped. After the power switch is turned off or the frequency conversion device is stopped, the cooling fan is continuously driven. If the use time of the frequency conversion device after the stop of the heating element becomes longer than the time set by the timer means, the operation of the cooling fan stops simultaneously with the stop of the frequency conversion device or the turning off of the power switch.

Therefore, when the heating element is stopped first and then the power switch is turned off or the frequency conversion device is stopped, the time during which the cooling fan continues to operate can be shortened.

According to the fifth means, the motor driving means is driven based on the contents stored in the storage means for storing the output state of the temperature detecting means in relation to the timing when both the heating element and the frequency converter are stopped. With this configuration, the temperature detected by the temperature detecting means exceeds a predetermined temperature at a time point when the driving of both the heating element and the frequency converter is stopped or immediately before, immediately after, or at a time point set in relation to the time point. And the output of the temperature detecting means becomes a predetermined state, the storing means stores the state, and the motor driving means is driven to cool even if the power switch is turned off or the heating element and the frequency converter are both de-energized. The fan operates continuously or stops for a very short time and then continues to operate.

That is, unlike the fourth means, the motor driving means is stored in the storage means for storing the output state of the temperature detecting means in relation to the timing at which both the heating element and the frequency converter are stopped. Because of the driving configuration, the heating element is stopped before the frequency conversion device, and at that time, even if the output state of the temperature detection means is in a state of driving the cooling fan, the frequency conversion device is stopped later with a delay, At that time, the cooling fan does not operate continuously unless the temperature inside the machine body has dropped and the output state of the temperature detecting means is not in a state of driving the cooling fan. Therefore, as compared with the fourth means, it is possible to reduce the chance that the cooling fan is continuously driven after the power switch is turned off or the frequency conversion device is stopped.

According to the sixth means, unlike the fourth means, the timer means for starting the accumulation of time in relation to the timing at which both the heating element and the frequency conversion device are stopped from being driven after the start of the accumulation of time Since a time-up signal is output after a lapse of a predetermined time and the driving of the motor driving means based on the stored contents of the storage means is prohibited, when a predetermined time has elapsed since both the heating element and the frequency conversion device were stopped driving,
After the power switch is turned off or the power switch is turned on, the power supply to both the heating element and the frequency converter is stopped, and then the operation of the cooling fan that continues to operate stops.

Therefore, when the temperature detected by the temperature detecting means exceeds a predetermined temperature, only the heating element is stopped and the frequency converter continues to operate.
In the fourth means, the operation time of the cooling fan motor after the operation of the frequency conversion device is stopped differs depending on the relationship between the stop timing of the heating element and the stop timing of the frequency conversion device. Becomes

According to the seventh means, the motor driving means is driven based on the contents stored in the storage means for storing the output state of the temperature detecting means in relation to the timing when both the heating element and the frequency converter are stopped. Since the configuration is the same as that of the fifth means, the chance that the cooling fan is continuously driven after the power switch is turned off or the frequency converter is stopped is reduced as compared with the fourth means. be able to. Further, when the timer means for starting the accumulation of time in relation to the timing at which both the heating element and the frequency conversion device are stopped driving starts the accumulation of the time, and outputs a time-up signal after a predetermined time has elapsed, the time of the storage means is reduced. Since the driving of the motor driving means based on the stored contents is prohibited, the operation time of the cooling fan motor after the power switch is turned off or after the operation of the heating element and the frequency conversion device is stopped as in the sixth means. In addition, it is possible to keep the temperature constant regardless of the relationship between the stop timing of the heating element and the stop timing of the frequency converter.

[0042]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the main body is constituted by an upper unit 26 and a lower unit 27, and the upper unit 26 is mounted on an upper unit case 28 made of an iron plate.
9 is fixed by a frame-shaped top frame 30 and is formed in a box shape, and a rear cover 31 provided with a plurality of air intake / exhaust holes is placed at the rear above the air intake / exhaust port. Top plate 2
A pattern 37 and a pattern 38 corresponding to the position of the heating coil for induction heating are printed on 9, and a pattern 39 corresponding to the nichrome heater is printed on the rear. The lower unit 27 is provided with a power switch 33, an operation unit 34 in which input keys are arranged, a display unit 35, and a heating cabinet door 36 on the front surface of a lower unit case 32 made of a substantially U-shaped iron plate. A heating chamber 49 is provided on the bottom surface of the lower unit case 32.

A printed wiring board is provided on the back surfaces of the operation unit 34 and the display unit 35, and a signal line 42a connected by a connector on the wiring board is connected by a connector 40 to a signal line 42b coming out of the upper unit 26. You. The connection line 43 is connected to the power switch 33 and is connected to a connection line 44 extending from the upper unit 26 by a connector 41. On both sides of the bottom surface of the upper unit case 28, an engaging portion 45 and an engaging portion 4 are provided.
6, the upper part of the side plate of the lower unit case 32 is woven inward and provided with an engaging part 47 and an engaging part 48.

FIG. 2 shows a plan layout of the internal components of the upper unit case 26. Inverter board 50 as main component
, An inverter board 51, a power supply board 52, a cooling fan 53, and a cooling fan 54 are arranged on the bottom surface of the upper unit case with an appropriate insulation distance set as shown in the figure. A heating coil 55 shown by a broken line is provided on the upper part of the inverter board 50, a heating coil 56 shown by a broken line is provided on the upper part of the inverter board 51, and a nichrome heater 57 shown by a broken line is provided on the upper part of the power supply board 52. And
FIG. 3 shows a partial cross section taken along the line AA ′ in FIG.

In FIG. 3, a heating coil 56 is fixed on a heating coil base 56b made of resin, a nichrome heater 57 is fixed on the bottom surface of a case 57a made of an inorganic material having a heat insulating effect, and a lower portion of the case 57a is made of aluminum. A heat insulating plate 57b formed of a plate is provided, and a power supply board 52 on which components such as the filter coil 102 and the filter coil 105 are mounted is provided below and near the heat insulating plate 57b. In FIG. 2, an intake duct 58, an intake duct 59, and an exhaust duct 60 are formed on both sides on the rear side, and a plurality of intake holes or exhaust holes are provided in the partition plate 61 correspondingly.

FIG. 4 is an overall circuit block diagram. In FIG. 4, a power supply board 52, an inverter board 50, an inverter board 51, and an operation board 62 are indicated by broken lines. The commercial power supply 63 is connected to the power supply board 52, and the filter capacitor 1
01 is connected between the lines. The power switch 33 has two contacts and turns on and off the input power of the inverter board 50 and the input power of the inverter board 51 at the same time. Power supply board 5
2, the filter coil 102 and the filter capacitors 103 and 104 connected between the power supply lines and the housing are connected between the power supplies on the inverter board 50 side as viewed from the switch 33, and the inverter board 51 side as viewed from the switch 33. Are connected to the filter coil 105 and filter capacitors 106 and 107 connected between each power supply line and the housing. Between the connection point between the power switch 33 and the input terminal of the filter coil 105 and the other pole terminal of the power supply line, a series circuit of the nichrome heater 57 and the relay 109 and a series circuit of the heating chamber heater 64 and the relay 110 are connected in parallel via the triac 108. The circuit is connected.

A series circuit of a parallel circuit of the fan motor 65 and the fan motor 66 and a triac terminal of the photo triac coupler 111 are connected between the input terminals of the power switch 33. The primary winding of the transformer 113 is connected between the input terminals of the power switch 33. The secondary winding of the transformer 113 is connected to a DC power supply circuit 114, and the DC power supply circuit 114 supplies a DC voltage to a relay drive circuit 115, a relay drive circuit 116, and a fan motor drive circuit 117.

The fan motor drive circuit 117 inputs the signals of the phototransistor 118a, the phototransistor 118b, and the temperature detection circuit 122 to drive the phototriac coupler 111 and the relay drive circuit 115.
Send a signal to As shown in FIG. 2, the temperature detection circuit 122 is a thermistor 121 fixed below the nichrome heater 57 and near the triac 108 on the power supply board 52.
A signal is output to the fan motor drive circuit 117 in accordance with the signal of (1). Display circuits 119 each including a light emitting diode
a and the display circuit 119b are provided.
9a turns on the light emitting diode in response to the input signal from the fan motor drive circuit 117, and the display circuit 119b turns on the light emitting diode in response to the input signal from the temperature detection circuit 122.

The input terminal of the inverter board 50 is connected to the output terminal of the filter coil 102 of the power supply board 52, and the primary winding of the transformer 202 is connected to the input terminal of the rectifier 203 via the fuse 201. Have been. An inverter circuit 204 that supplies a high-frequency current to the heating coil 55 is connected to an output terminal of the rectifier 203. The control circuit 205 is a circuit that drives a switching element of the inverter circuit 204 to control the output. The secondary winding of the transformer 202 is connected to a DC power supply circuit 206, and the DC power supply circuit 206
2 is supplied with a DC power supply. The control circuit 205 also controls the phototransistor 118
b.

The configuration of the inverter board 51 is the same as the configuration of the inverter board 50, and the description is omitted. Operation board 6
The output signal of the input circuit 301 is supplied to the control circuit 205, and the output signal of the input circuit 302 is supplied to the control circuit 215. The control circuit 302 includes a phototransistor 303
And an output signal to the phototransistor 304, and the output signal of the phototransistor 303 is
And the output signal of the phototransistor 304 is output to the relay drive circuit 116. The input circuit 302 is connected to the gate-T of the triac 108.
Triac coupler 12 connected between two via a resistor
0 drive signal is output.

The operation of the induction heating cooker configured as described above will be described. In FIG. 1, when the apparatus is installed on a sink or the like, first, the upper unit 26 is dropped into a rectangular hole formed in a top plate of the sink or the like. The upper unit 26 is supported on a top plate surface by a top frame 30. In this state, the lower unit 27 is inserted from the front of the hole provided on the front surface of the sink or the like into the engaging portion 4 of the upper unit 26.
5 and 46 and the engaging portions 47 and 48 of the lower unit 27 are inserted so as to mesh with each other.
7 so that the lower unit can be suspended. The connector 40 and the connector 41 can be connected in the middle of the insertion of the lower unit.

When the power switch 33 is turned on and the input key of the operation section 34 is pressed, the upper unit 26 shown in FIG.
A fan motor drive circuit provided on the power supply board 52 simultaneously drives the cooling fan 53 and the cooling fan 54. Inhale each air. The air blown from the outlets of the cooling fans 53 and 54 is supplied to the inverter board 50 and the inverter board 5.
After the heat-generating components and electronic components on each inverter board 50 are cooled by the guides provided on the respective components 1, the heat-generating components and electronic components are folded back at the center to cool the electronic components on the power supply board 52 and provided on the wall in front of the exhaust duct 60. The air is exhausted from the plurality of holes through the exhaust duct to the upper outdoor.

Inverter board 50 and inverter board 51
When the inverter circuit operates, a high-frequency current is supplied to the heating coils 55 and 56, and a high-frequency magnetic field is generated from each heating coil.
The pot placed on top generates heat. The high-frequency magnetic field generated from the heating coil 55 and the heating coil 56 is generated not only toward the pan but also around the pot, but as shown in FIG. Is provided, and this shields the magnetic field generated by the heating coil 55 and the heating coil 56, so that the magnetic field intensity at the lower part thereof is reduced.

On the other hand, the shielding plate 57b of the nichrome heater 57
Since components having a commercial power supply potential such as the filter coil 102 and the filter coil 105 are mounted on the power supply board 52 in the lower part of the figure, the intensity of the magnetic field generated by the heating coil 50 and the heating coil 51 is reduced as described above, It is possible to suppress high frequency noise from being superimposed on the commercial power supply potential and leaking to the commercial power supply side of the device.

Next, the operation of the electric circuit block will be described.
When the power switch 33 is turned on in FIG.
3 is rectified by the rectifier 203 and the inverter circuit 20
4 is supplied with a DC voltage. When an on / off key for driving the heating coil 55 (corresponding to the heating pattern 37) is pressed among the input keys of the operation unit 34 of FIG. 1, a heating signal is input from the input circuit 301 of the operation board 62 in the circuit diagram of FIG. Is output to the control circuit 205, and the control circuit 205 outputs a high-frequency drive pulse to drive the semiconductor element of the inverter circuit 204, and causes the heating coil 55 to generate a resonance current due to resonance between the resonance capacitor and the heating coil 55. The transformer 202 supplies an AC voltage to the DC power supply circuit 206,
The DC power supply circuit 206 converts this to a smoothed DC and supplies it to the control circuit 205 and the input circuit 301. However, since the primary winding of the transformer 202 is connected to the power supply switch 33 and the load side of the fuse 201, Power switch 33
Alternatively, when the fuse 201 is cut off, the supply of DC power is stopped. The same applies to the operation of the circuit block of the inverter board 51 that drives the heating coil 56 (corresponding to the heating pattern 38).

When the on / off key of the operation unit 34 (FIG. 1) for driving the nichrome heater 57 (corresponding to the heating pattern 39 in FIG. 1) is pressed, the input circuit 302 of the operation board 62 accepts this and a delay of 2 seconds. After a time, the drive signal of the relay 109 is output to the relay drive circuit 115 via the phototransistor 303 to drive the relay 109. Input circuit 30
2 outputs a drive signal of the triac coupler 120 about 50 ms after the drive signal of the relay 109 is output, and the triac 108 is turned on.

The heater 6 in the operation unit 34 (FIG. 1)
When the on / off key for driving the button 4 is pressed, the input circuit 302 of the operation board 62 receives the key and outputs a drive signal of the relay 116 to the relay drive circuit 116 via the phototransistor 304 after a delay time of 2 seconds, thereby turning the relay 110 on. Drive. The input circuit 302 outputs a drive signal of the triac coupler 120 about 50 milliseconds after the output of the drive signal of the relay 116, and the triac 108 is turned on.

When the control circuit 205 receives a drive signal for the inverter circuit 204 from the input circuit 301, the fan motor drive circuit 117 via the phototransistor 118b.
When the control circuit 215 receives a drive signal for the inverter 214, the nichrome heater 57, or the heating chamber heater 64 from the input circuit 302, the fan motor drive circuit 117 via the phototransistor 118a.
When the fan motor drive circuit 117 receives any one of these drive signals, it drives the phototriac coupler 111 to operate the fan motor 65 and the fan motor 66.

A thermistor 121 is mounted on the power supply board 52. When the temperature of the thermistor 121 rises to about 90 ° C. or more, the temperature detection circuit 122 outputs a fan motor drive signal to the fan motor drive circuit 117. Even if the power switch 33 is turned off, the fan motor 6
5 and the fan motor 66 to drive the nichrome heater 57
It is possible to prevent the electronic component from being overheated and destroyed due to the overshoot of the temperature due to the residual heat of the heating chamber heater 64 or the heating chamber 49 (FIG. 1).

The fan motor drive circuit 117 receives the fan motor drive signal output from the temperature detection circuit 122, and displays the display circuit 119a when the drive signal for the phototriac coupler 111 is not input from the phototransistor 118a or 118b. To output a drive signal. The display circuit 119a turns on the light emitting diode when the driving signal is input. Therefore, the temperature of the thermistor 121 is high immediately after the energization of all the heating means is stopped while the power switch 33 is on, or immediately after the power switch is turned off during use, and the fan motor 6
The display circuit 119 lights up when the operation of the fan motors 5 and 66 continues, so that the user can know the reason why the fan motors 65 and 66 operate even after the power switch is turned off.

When the temperature of the thermistor 121 is about 105
When the temperature rises to more than ° C., the temperature detection circuit 122 outputs a prohibition signal to the relay drive circuit 115 to stop the operation of the nichrome heater 57 and prevent the electronic components from overheating. The temperature detection circuit 122 outputs the above-mentioned prohibition signal to the relay drive circuit 115 and simultaneously outputs a drive signal to the display circuit 119b. When the display circuit circuit 119b receives this signal, the light-emitting diode is turned on. Can be found to be caused by an abnormal rise in internal temperature.

The DC power supply circuit 114 rectifies and smoothes the output of the secondary winding of the transformer 113 and supplies DC power to the relay drive circuit 115, the relay drive circuit 116, and the fan motor drive circuit 117. Since the windings are connected to the power supply side of the power switch 33, the fuse 201, and the fuse 202, the supply of DC power is continued even if these are cut off.

As described above, according to the present embodiment, there is provided the temperature detecting circuit 122 which detects the temperature by the thermistor 121 and outputs a motor drive signal when the temperature exceeds about 90 ° C. When a motor drive signal is output, or one of the inverter circuit 204, the inverter circuit 214, the nichrome heater 57, and the overheater heater is driven, the fan motor 6
5 and the fan motor 66 are driven, so that the fan motor 65 and the fan motor 66 can be driven not only when the device is performing the heating operation but also after the device heating operation is stopped or the power switch 33 is turned off. To prevent the temperature of the electronic component from rising (overshooting) due to the residual heat of the nichrome heater 57 and the heating chamber heater 64 after the heating operation of the device is stopped or the power switch 33 is turned off. be able to.

When the temperature of the thermistor 121 is about 105
When the temperature exceeds ℃, the heating operation of the nichrome heater 57 is stopped, so that destruction of internal components due to the thermal influence of the nichrome heater 115 can be reliably prevented.

As described above, a two-step criterion is provided for the temperature detected by the thermistor 121, and the function of protecting the components against the thermal influence of the nichrome heater 57 is divided into two steps, whereby the heating of the nichrome heater 57 is prohibited by the protection circuit. It is possible to reduce the chance that a situation extremely inconvenient for the user occurs.

Further, when the nichrome heater 57, the heating chamber heater 64, the inverter circuit 204, and the inverter circuit 214 are not all driven and the temperature detection circuit 122 is in a state of outputting a drive signal to the fan motor drive circuit 117, Display circuit 119a for lighting a light emitting diode
And the display circuit 119b which is turned on when the temperature detection circuit 122 inhibits the operation of the nichrome heater 57 is provided, so that the user knows that the protection operation function by the temperature detection circuit 122 is operating. Can be
It is possible to eliminate the risk of being mistaken for a failure or giving the user an uneasy feeling.

Further, according to the structure of this embodiment, the upper unit 2
Because we were able to concentrate most of the electronic components on 6,
The lower unit 27 includes a heating chamber 49, an operation unit 34, and a display unit 3.
Since only about 5 parts are stored or placed, the weight of the lower unit 27 is reduced, and the work of suspending the lower unit 27 to the upper unit 26 during installation can be facilitated.

In the above embodiment, the fan motor 65 and the fan motor 66 are connected as an AC motor to the commercial power supply of the power switch 33 in series with the phototriac coupler 111. However, a DC motor is used instead of the AC motor. The input terminal of the DC power supply circuit of the drive circuit of the DC motor may be connected to the commercial power supply side of the power switch 33.

In the above embodiment, the temperature detection circuit 122
When the temperature of the thermistor 121 rises, a drive signal is output to the fan motor drive circuit 117. However, the present invention is not limited to this configuration. For example, when the temperature of the thermistor 121 rises and the temperature of another specific portion becomes a predetermined temperature. If the temperature exceeds the predetermined value, a driving signal is output to the fan motor driving circuit 117, or if the temperature of the thermistor 121 exceeds a predetermined temperature and continues for a predetermined time, the fan motor driving circuit 11
7 can be easily realized by using a microcomputer, and at least a nichrome heater 57 can be used.
Alternatively, the same applies if a temperature detection circuit 122 for driving the fan motor 66 is provided on condition that the temperature of the thermistor 121 for detecting the temperature of a portion that changes depending on the temperature of the heating chamber heater 64 exceeds a predetermined temperature. The effect of can be obtained.

Further, in the above embodiment, the frequency converter is 2
Although a heating cooker provided with one heater, one nichrome heater and one heating chamber heater, the same effect can be obtained with, for example, one frequency converter and one heating chamber heater, and the combination may be changed as appropriate. The same effect can be obtained as long as the heating cooker has at least one or more frequency converters and a heating element that is heated by one or more commercial frequency heating sources.

Embodiment 2 Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

In FIG. 5, the fan motor drive circuit 402 connected between the power supply terminals on the side of the AC power supply 63 as viewed from the power switch 33 includes a storage circuit 403 and a timer circuit 404.
And the output signal of the input circuit 406, the fan motor 4
12 is driven. The thermistor 400 is a heating chamber heater 41
It is attached to the wall of the heating cabinet that houses 1
The signal of the thermistor 400 is input to the temperature detection circuit 401, and the output signal of the temperature detection circuit 401 is
3 is input.

The input circuit 406 inputs a heating command or an output setting command by a tact switch or the like, and sends an output signal to the fan driving circuit 402, the relay driving circuit 405, the inverter control circuit 407, and the timer circuit 404. The input circuit 406 receives a signal from the power switch on / off detection circuit 413 and outputs a signal to the storage circuit 403. The inverter circuit 408 is controlled by the control circuit 407 and supplies a high-frequency current to the heating coil 409. The relay drive circuit 405 and the relay 410 control ON / OFF of the heating chamber heater 411.

The operation of the heating cooker configured as described above will be described below. When the power switch 33 is turned on and the heating coil 40 is
When the drive command of No. 9 or the command of the heater 411 is input, the input circuit 406 outputs a fan drive signal to the fan motor drive circuit 402, and the fan motor drive circuit 402 receives the signal and drives the fan motor 412. The input circuit 406 sends a drive signal to the control circuit 407 when a drive command for the heating coil 409 is input, oscillates the inverter circuit 408, and outputs a signal to the relay drive circuit 405 when a drive signal for the heater 411 is input. To feed power to the roaster heater.

The input circuit 406 also receives the output signal of the power switch on / off detection circuit 413,
3 is monitored, and the energization state of the heating coil 409 and the heating chamber heater 411 is monitored by a command input with the tact key. When the power switch 33 is turned off or the power switch 33 is turned on, An energization stop determination signal that can determine when both the heating coil 409 and the heating chamber heater 411 are in a non-energized state is output to the storage circuit 403.

The temperature detection circuit 401 periodically measures the temperature of the thermistor 400, and when the temperature of the
When the temperature reaches 00 ° C., an arrival signal is output to the storage circuit 403. The storage circuit 403 does not output the drive signal of the fan motor 412 to the fan motor drive circuit 402 when the non-arrival signal is input from the temperature detection circuit 401, and when the arrival signal is output, When the power supply stop determination signal is input from the input circuit 406, the arrival signal is stored and a drive signal is output to the fan motor drive circuit 402, so that the fan motor 412 is driven. That is, the storage circuit 4
03 is outputting a drive signal to the fan motor drive circuit 402, and the input signal from the temperature detection circuit 401 is
When the signal changes from the arrival signal to the non-arrival signal, the storage circuit 403
Stops outputting the drive signal to the fan motor drive circuit 402 unconditionally. On the contrary, even if the input signal from the temperature detection circuit 401 changes from the non-arrival signal to the arrival signal, the power supply from the input circuit 406 is stopped. The storage circuit 403 does not output a drive signal to the fan motor drive circuit 402 unless a determination signal is input.

The input circuit 406 outputs to the timer circuit 404 signals corresponding to the on / off state of the power switch 33 and the drive state and stop state of the heater 411. The timer circuit 404 resets the output signal and the integrated value of time when the driving state signal of the heating chamber heater 411 is input, stops the integrating operation, and inputs the OFF state signal of the power switch 33 or the stop state signal of the heating chamber heater 411. The time accumulation operation is started, and when about 10 minutes have elapsed, a time-up signal is output to the fan motor drive circuit 402. The fan motor drive circuit 402 prohibits the drive of the fan motor 412 by the drive signal of the storage circuit 403 when the timer circuit 404 outputs the time-up signal.

As described above, according to this embodiment, when the power switch 33 is turned off from on or when the power switch 33 is on and the heating coil 409 and the heating chamber heater 411 are both de-energized. Since the memory circuit 403 for storing the content of the output signal of the temperature detection circuit 401 in the above and outputting a signal in accordance with the stored content is provided,
When the power switch 33 is turned off from on or after the power switch 33 is on and the heating coil 409 and the heating chamber heater 411 are both de-energized, the temperature of the thermistor 400 rises and the fan motor 412
It is possible to prevent the unnatural phenomenon that the device starts operating.

The above-described effect can be obtained even when the timer circuit 403 is omitted, but the operation is continued after all the heat sources are turned off with the power switch 33 turned off or the power switch 33 is turned on. When the signal output from the temperature detection circuit 401 changes from the arrival signal to the arrival signal, the fan motor 412 that has stopped operating stops when the internal temperature decreases slowly. It can be quite long.

As shown in the above embodiment, when the timer circuit 403 is added, the power switch 33
When the heater is turned off and the heating heater 411 is de-energized, the timer circuit 403 inhibits the drive of the fan motor 412 by the storage circuit 403 when the heating heater 411 is de-energized. Shooting can be reliably prevented, and the fan motor 412 can be prevented from operating longer than necessary.

Although the above-described effect can be obtained even when the timer circuit 403 is omitted, the operation is continued after all the heat sources are turned off when the power switch 33 is turned off or the power switch 33 is turned on. When the fan motor 412 stops operating when the signal output from the temperature detection circuit 401 changes from the arrival signal to the arrival signal, the time until the operation stops varies depending on the state of the internal temperature.

Embodiment 3 Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

In FIG. 6, blocks having the same functions as those in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. The differences from FIG. 5 will be described below. The storage circuit 403 in FIG. 5 is configured by a flip-flop IC 415 in FIG.
The timer circuit 404 is constituted by a timer IC 416 in FIG. The clock input terminal (CK) of the flip-flop IC 415 and the reset input terminal (R) of the timer IC 416 are both connected to the collector terminal of the transistor 425 that drives the drive coil of the relay 410. 4, an inverter circuit 428 for supplying a high-frequency current to the heating coil 427 and its control circuit 433, and an inverter circuit 430 for supplying a high-frequency current to the heating coil 429 and its control circuit 434 are provided. Control circuit 433 via photocoupler 436
And the output signal of the control circuit 434 are input to the display circuit 437, and the display circuit 437 is also connected to the cathode of the diode input terminal of the phototriac coupler 440 for driving the fan motor 412.

A transistor 438 and a transistor 439 are connected in parallel between the cathode of the diode input terminal of the phototriac coupler 440 and the common potential, and the base of the transistor 438 and the positive terminal of the DC power supply (hereinafter referred to as VDD).
), The resistor 421, the resistor 422, and the emitter-collector of the transistor 420 are connected in series.
The base of the transistor 420 is a flip-flop IC4
15 is connected to the output terminal (Q) via a resistor 417,
The data input terminal (D) and the set input terminal (S) of the flip-flop IC 415 are both connected to the output terminal of the temperature detection circuit 401. The base of the transistor 439 is connected to the emitter terminals of the output transistors of the photocouplers 435 and 436 via the resistor 441.

The input circuit 442 drives the transistor 425 via the photocoupler 443 to drive the drive coil of the relay 410, and sends a drive signal to the control circuits 433 and 434. The input circuit 442 is the control circuit 4
A system for sending an output signal to the control circuit 334 and a system for sending an output signal to the control circuit 434 are internally separated, and operate at different potentials. VDD is supplied by rectifying and smoothing the output voltage of the transformer 444 connected to the power supply side of the power switch 33. When the power switch 33 is turned off, the input circuit 442, the control circuit 433, and the control circuit 4
34, the supply of control power to the photocoupler 44 is stopped.
3, the photocoupler 435 and the photocoupler 436 are turned off.

The display circuit 437 receives the signals of the photocouplers 435 and 436 and the cathode potential on the input side of the phototriac coupler 440, and turns on the LED according to the state of the signal.

The operation of the heating cooker configured as described above will be described below. When a heating command is sent from the input circuit 442 to the control circuit 433, the control circuit 433 drives the inverter circuit 428 and the photocoupler 435, and the transistor 439 is turned on, so that the phototriac coupler 440 is turned on and the fan motor 412 is turned on. And the fan motor 412 rotates. Similarly, even if a heating signal is output from the input circuit 442 to the control circuit 434, the fan motor 412 rotates. The input circuit 442 also outputs the drive signal to the photocoupler 443 and the control circuit 433 supplies the photocoupler 4
It is configured to output 35 drive commands. Therefore, the heating chamber heater 411 and the heating coil 4
When a heating command is output to at least one of the heating coil 27 and the heating coil 429, the fan motor 412 rotates.

If the temperature of the thermistor 400 is 100 ° C. or lower, the level of the output terminal of the temperature detection circuit 401, that is, the level of the set input terminal (S) of the flip-flop IC 415 becomes HI, and the reset input terminal (R)
Is fixed to the Lo level, the level of the output terminal (Q) becomes HI, and the PNP transistor 420 is turned off. Therefore, since the transistor 438 is off, the rotation of the fan motor 412 stops at the same time as the transistor 439 turns off.

When the temperature of the thermistor 400 exceeds 100 ° C., the output of the temperature detection circuit 401, that is, the level of the set input terminal (S) of the flip-flop IC 415 becomes Lo, so that the output terminal (Q) of the flip-flop IC 415 The level of the data input terminal (D) when the level of the clock input terminal (CK) rises is output, and the level of the clock input terminal (CK) is changed from Lo to H.
When it does not rise to I, the level of the output terminal (Q) is held as it is.

When the relay 410 is turned off from the on state and the heater 411 is turned off from the energized state, that is, when the transistor 425 is turned off from the on state, the clock input terminal (CK) of the flip-flop IC 415 Rises from Lo to HI. At this time, if the data input terminal (D) and the set input terminal (S) of the flip-flop IC 415 are Lo, the output terminal (Q) of the flip-flop IC 415 is Lo. In this case, since the transistor 420 is turned on, the transistor 438 is turned on, and the phototriac coupler 440 is driven.

In this case, even if the transistor 439 is turned off, the fan motor 412 rotates. That is, when all of the heating coil 427, the heating coil 429, and the heating heater 411 are not driven, or the power switch 33 is turned off, the fan motor 412 rotates.

When the transistor 425 is turned off, the level of the reset input terminal (R) of the timer IC 416 changes from Lo to HI, and the level of the output terminal (OUT) changes from Lo to HI. At the same time, the timer IC 416 performs the time measurement operation. The measurement operation is stopped after about 10 minutes have elapsed, and the level of the output terminal (OUT) is changed from HI to L.
It becomes o. At this time, the base of the transistor 438 is fixed to Lo via the diode 419, so that the transistor 4
Even if 20 is on, transistor 438 does not turn on.

Therefore, the phototriac coupler 440 is driven by the transistor 438 and the fan motor 412 rotates only when the temperature of the thermistor 400 becomes 1 at the time when the energization of the heater 411 is stopped.
This is a case where the temperature is higher than 00 ° C., and about 10 minutes after the energization of the heating chamber heater 411 is stopped.

The display circuit 437 is connected to the photocoupler 43
5, Lights when the input signal from the photocoupler 436 is Lo and the signal from the cathode terminal on the diode input side of the phototriac coupler 440 is Lo.

As described above, according to the present embodiment, the output state of the flip-flop IC 415 which stores the output state of the temperature detection circuit 401 at the time when the heating heater 411 changes from the energized state to the non-energized state is determined. The timer IC 416 that drives the fan motor 412 and starts the accumulation of time from the time when the heating chamber heater 411 changes from the energized state to the non-energized state. Therefore, even if the power switch 33 is turned off, the fan motor 41
2 does not stop immediately, and continues to operate for about 10 minutes, so that the temperature inside the device does not overshoot due to the effect of the residual heat of the heater 411, and the electronic components are not thermally destroyed.

Further, since the timer IC 416 starts to accumulate the time almost in synchronization with the stop of the energization of the heating chamber heater 411, the heating coil 427 after the energization of the heating chamber heater 411 is stopped.
If the heater coil 429 is continuously energized, the timer I
C continues the time accumulation operation. Therefore, when the power switch 33 is turned off next time, the fan motor 412 does not operate for about 10 minutes, but the time from when the heater 411 is turned off until the power switch 33 is turned off, or when the power switch 33 is turned off. Is less than the above-mentioned about 10 minutes, by the operating time until all the heat sources are turned on and
The operation time of the fan motor 412 after the power switch 33 is turned off can be shortened. Also, the heating chamber heater 411
After the fan motor 412 is stopped from the energized state to the non-energized state, the temperature of the thermistor 400 rises for a while due to the residual heat of the internal high-temperature components, the output of the temperature detection circuit 415 becomes Lo, and the fan An unnatural phenomenon that the motor 412 starts operating again can be prevented.

Embodiment 4 Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. 7 is different from FIG. 6 in that a resistor 446 and a transistor 4 connected between VDD and a common potential are connected.
47, a collector-emitter series connection circuit, and a resistor 4 connected between the base of the transistor 447 and the emitter terminals of the output transistors of the photocouplers 435 and 436.
48, and connects the clock input terminal (CK) of the flip-flop IC 415 to the collector of the transistor 447. Components or circuit blocks denoted by the same reference numerals as in FIG. 6 perform the same function.

The operation of the cooking device configured as described above will be described below. With the above configuration, the output terminal (Q) of the flip-flop IC 415 becomes Lo because the data terminal (D) and the set input terminal (S) of the flip-flop IC 415 become Lo and the photocouplers 435 and 436 This is the time when the emitter of the output transistor changes from HI to Lo.

Therefore, as described in the third embodiment, the power switch 33 is turned off or the heating coil 427 is turned off.
When either the heating coil 429 or the heating chamber heater 411 is energized, and all become non-energized, the transistor 439 is turned off and the driving of the fan motor 412 is stopped, but the transistor 447 is turned on from off. Therefore, if the temperature of the thermistor 400 exceeds 100 ° C. at that time, the output terminal (Q) of the flip-flop IC becomes Lo, and the transistor 438 is turned on, so that the driving of the fan motor 412 is continued. Thereafter, the time during which the fan motor 412 operates is determined by the timer IC 416, as in the third embodiment, and operates for about 10 minutes after the driving of the heating chamber heater 411 is stopped.

As described above, according to this embodiment, the temperature detection circuit 401 at the time when the driving of the heating chamber heater 411, the inverter 428, and the inverter 429 are all stopped.
The fan motor 412 is driven by the output signal of the flip-flop IC 415 that stores the output state of the timer 416. The timer IC 416 starts time integration from the time when the driving of the heating chamber heater 411 is stopped.
Since C416 is configured to prohibit driving of the fan motor 412 by the output signal of the flip-flop IC 415, the same effect as that of the third embodiment can be obtained.
There are the following advantages as compared with the third embodiment.

That is, in the third embodiment, the heating chamber heater 41
Since the fan motor 412 was driven by storing the output state of the temperature detection circuit 401 at the time when the power supply to the heater 1 was stopped, when the heater 411 was stopped before the inverter 428 or 429, When the power switch 33 is turned off, the temperature of the thermistor 400 is low, and the output of the temperature detection circuit 401 is HI.
, The fan motor 412 may be driven continuously, but this does not occur in the configuration of the present embodiment. Therefore, the chance that the fan motor 412 operates continuously after the power switch 33 is turned off can be reduced.

Embodiment 5 Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. 8 is different from FIG. 6 in that a resistor 450 and a transistor 4 connected between VDD and a common potential are connected.
49, a collector-emitter series connection circuit, and a resistor 4 connected between the base of the transistor 449 and the emitter terminals of the output transistors of the photocouplers 435, 436.
51, the reset input terminal (R) of the timer IC 416 and the collector of the transistor 449 are connected. Components or circuit blocks denoted by the same reference numerals as in FIG. 6 perform the same function.

The operation of the heating cooker configured as described above will be described below. With the above structure, the timer IC 416 starts accumulating time when the transistor 449 is turned off from the on state.
Therefore, the heating chamber heater 411 or the inverter 4
When the output terminal (Q) of the flip-flop IC 415 is Lo when at least one of the inverters 28 or 430 is turned on and all of them are turned off, the timer IC 4
The operation of the fan motor 412 continues for about 10 minutes until the output terminal (OUT) becomes Lo at the time when 16 is timed out.

As described above, according to the present embodiment, the flip-flop IC 4 for storing the output state of the temperature detecting circuit 401 at the time when the driving of the heating chamber heater 411 is stopped.
The fan motor 412 is driven by the 15 output signals,
Heating chamber heater 411, inverter 428, and inverter 4
The timer IC 416 starts to accumulate time from the time point when the driving of all the ICs 29 is stopped.
Since the configuration is such that driving of the fan motor 412 by the output signal of the output signal 415 is prohibited, the same effect as that of the third embodiment is obtained, and the following advantages are obtained as compared with the third embodiment.

That is, in the third embodiment, the heater 41
In the case where the power supply stop time of 1 precedes the stop time of the other heating source or the power switch off time, the subsequent operation time of the fan motor 412 varies depending on the preceding time. However, in the configuration of the present embodiment, such a phenomenon does not occur, and the time from the reset release of the timer to the time up can be kept constant at about 10 minutes.

Embodiment 6 Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings. 9 differs from FIG. 8 in that the clock input terminal (CK) of the flip-flop IC 415 is connected to the collector of the transistor 449. Components or circuit blocks denoted by the same reference numerals as in FIG. 8 perform the same function.

The operation of the heating cooker configured as described above will be described below. With the above configuration, the output terminal (Q) of the flip-flop IC 415 becomes Lo when the transistor 449 changes from on to off while the temperature of the thermistor 400 exceeds about 100 ° C. The operation of the fan motor 412 continues for about 10 minutes until the time of the IC 416 is up and the output terminal (OUT) becomes Lo.

As described above, according to the present embodiment, the temperature detecting circuit 401 at the time when the driving of the heating chamber heater 411, the inverter 428, and the inverter 429 are all stopped.
The fan motor 412 is driven by the output signal of the flip-flop IC 415 that stores the output state of the timer I.
C416 starts time accumulation, and when about 10 minutes have elapsed, the timer IC 416 is configured to prohibit the driving of the fan motor 412 by the output signal of the flip-flop IC 415, so that the same effect as that of FIG. There are the following advantages as compared with FIG.

That is, in FIG. 8, when the power supply to the heating chamber heater 411 is stopped, it is determined whether or not to drive the fan motor 412 after turning off the power switch 33 or after stopping all the heating sources. If the power supply stop time of 411 precedes the stop time of another heating source or the power switch 33 off time, the temperature of the thermistor 400 decreases at the power switch 33 off time or the power supply stop time of all heating sources. Even if it is, it may drive continuously. However, in the configuration of the present embodiment, the temperature of the thermistor 400 is detected at the time when the power switch 33 is turned off or when the power supply to all the heating sources is stopped, and it is determined whether to continuously drive the fan motor 412. The opportunity to continuously operate the fan motor 412 can be reduced as compared with FIG.

[0111]

As described above, the first means of the present invention comprises storage means for storing the content of the output signal of the temperature detecting means at a predetermined time and outputting a signal in accordance with the stored content. A state in which the storage means outputs a predetermined signal,
Alternatively, when any one of the states in which the frequency conversion device is driven or the heating element is driven occurs, the motor driving means of the cooling fan is driven.
After turning off the power switch or turning off all heating sources, even if the cooling fan normally stops operating, the cooling fan can be driven and the power switch can be turned off from the energized state. Alternatively, it is possible to eliminate an unnatural operation in which, after turning off all the heating sources and once stopping the cooling fan, the cooling fan starts operating after a while, without doing anything.

Further, the second means of the present invention includes timer means, and the period during which the predetermined signal output from the storage means is output is set by the timer means, so that the internal temperature rises above the set temperature. In this case, the time for continuously operating the cooling fan after turning off the power switch or the heating source can be set to a necessary time.

Further, the third means of the present invention provides a display or notifying that at least the frequency converter and the heating element are not driven and the storage means outputs a predetermined output signal to drive the cooling fan. Since the apparatus is provided, even if the power supply is turned off or all the heating sources are de-energized, it is possible to prevent the user from erroneously determining that the cooling fan is operating as a malfunction.

The fourth means of the present invention drives the motor driving means based on the contents stored in the storage means for storing the output state of the temperature detecting means in relation to the timing at which the driving of the heating element is stopped. After the timer means for starting the accumulation of the time in relation to the timing at which the body is stopped driving starts the accumulation of the time, and outputs a time-up signal after a lapse of a predetermined time, the motor driving means based on the contents stored in the storage means. Since the driving is prohibited, the time during which the cooling fan continues to operate after the power switch is turned off or after all the heating sources are de-energized can be shortened without deteriorating the cooling performance.

The fifth means of the present invention is a motor driving means based on the contents of the storage means for storing the output state of the temperature detecting means in relation to the timing when both the heating element and the frequency converter are stopped. When the timer means for starting the integration of the time in relation to the timing at which the heating element is stopped driving starts the integration of the time and outputs a time-up signal after a lapse of a predetermined time, the content of the storage means is stored. Since the driving of the motor driving means is prohibited, it is possible to reduce the chance of the cooling fan continuing to operate without deteriorating the cooling performance after the power switch is turned off or after all the heating sources are de-energized. it can.

The sixth means of the present invention drives the motor driving means based on the contents stored in the storage means for storing the output state of the temperature detecting means in relation to the timing at which the driving of the heating element is stopped. After the timer means for starting the accumulation of time in relation to the timing when both the body and the frequency converter are stopped driving starts the accumulation of the time, and outputs a time-up signal after a predetermined time has elapsed, the contents of the storage means are stored. Since the driving of the motor driving means is prohibited, the operation time when the cooling fan continues to operate after the power switch is turned off or after all the heating sources are de-energized can be kept constant.

Further, the seventh means of the present invention is a motor driving means based on the contents stored in the storage means for storing the output state of the temperature detecting means in relation to the timing when both the heating element and the frequency converter are stopped. When the timer means for starting the accumulation of time in relation to the timing at which both the heating element and the frequency conversion device are stopped driving starts the accumulation of time, and outputs a time-up signal after a lapse of a predetermined time,
Since the driving of the motor driving means based on the storage contents of the storage means is prohibited, the opportunity for the cooling fan to continuously operate after the power switch is turned off or after all the heating sources are de-energized is reduced, and the operation time is reduced. Can be constant.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a cooking device according to a first embodiment of the present invention.

FIG. 2 is an internal plan view of the cooking device.

FIG. 3 is a sectional view of a main part of the cooking device.

FIG. 4 is a circuit block diagram of the cooking device;

FIG. 5 is a circuit block diagram of a heating cooker according to a second embodiment of the present invention.

FIG. 6 is a circuit block diagram of a cooking device according to a third embodiment of the present invention.

FIG. 7 is a circuit block diagram of a heating cooker according to a fourth embodiment of the present invention.

FIG. 8 is a circuit block diagram of a cooking device according to a fifth embodiment of the present invention.

FIG. 9 is a circuit block diagram of a cooking device according to a sixth embodiment of the present invention.

FIG. 10 is a perspective view of a conventional heating cooker.

[Explanation of symbols]

 33 Power switch 53,54 Cooling fan 55,56 Heating coil 57 Nichrome heater (heating element) 64 Heating chamber heater (heating element) 65,66 Fan motor (cooling fan) 67,68 Frequency converter 108 Triac (heating element control means) 109, 110 Relay (heating element control means) 111 Phototriac coupler (motor driving means) 119a, 119b Display circuit (display device) 121 Thermistor (temperature detection means) 122 Temperature detection circuit (temperature detection means) 204, 214 Inverter circuit (Frequency conversion device) 205, 215 Control circuit (Frequency conversion device) 400 Thermistor (Temperature detection means) 401 Temperature detection circuit (Temperature detection means) 403 Storage circuit (Storage means) 404 Timer IC (Timer means) 405 Relay drive circuit ( Heating element control Stage) 407 control circuit (frequency converter) 408 inverter circuit (frequency converter)

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-263784 (JP, A) JP-A-3-233224 (JP, A) JP-A-4-137389 (JP, A) JP-A-3-263 213908 (JP, A) JP-A-4-64820 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05B 11/00 H05B 6/12

Claims (7)

(57) [Claims] 1. A heating coil, a frequency conversion device for supplying a high-frequency current to the heating coil, a heating element that generates heat by passing a current of a commercial frequency, and a heating element control unit that controls energization of the heating element. A cooling fan that cools electrical components, a power switch that switches connection and disconnection of the frequency converter or the heating element to and from commercial power, and a motor of the cooling fan that is connected to the commercial power side of the power switch. Temperature detecting means for detecting a temperature of a portion which changes depending on the temperature of the heating element and outputting a predetermined signal on condition that the temperature exceeds at least a predetermined temperature; and detecting the temperature at a predetermined time. Storage means for storing and outputting a predetermined output signal according to the state of the output signal of the means, wherein at least the storage means outputs the predetermined signal The heating cooker is configured to drive the motor driving means of the cooling fan when any one of a state, a state in which the frequency converter is driven, and a state in which the heating element is driven occurs. 2. A comprising a timer means, the heating cooker of claim 1, wherein the period of output of a predetermined signal outputted from the storage means is set by said timer means. 3. A not least the frequency converter and the heating element are both driven, the storage means according to claim 1, wherein provided a display device for displaying or notifying the cooling fan and outputs a predetermined output signal is a state of operation Heating cooker. 4. A timer means for starting integration of time in relation to a timing at which the heating element is stopped, and a storage for storing an output state of the temperature detection means in relation to the timing at which the heating element is stopped. Means for driving a motor driving means based on the contents stored in the storage means, and outputting a time-up signal after a lapse of a predetermined time after the timer means starts accumulating time. 3. The cooking device according to claim 2, wherein the driving of the motor driving means based on the control is prohibited. 5. An output of a timer means for starting integration of time in relation to a timing at which the heating element is stopped, and an output of a temperature detecting means in relation to a timing at which both the heating element and the frequency converter are stopped. It comprises a storage unit for storing a state, drives a motor drive unit based on the storage content of the storage unit, and after the timer unit starts accumulating time, outputs a time-up signal after a lapse of a predetermined time,
3. The cooking device according to claim 2, wherein the driving of the motor driving means based on the contents stored in the storage means is prohibited. 6. A timer means for starting integration of time in relation to a timing at which both the heating element and the frequency converter are stopped, and an output of a temperature detection means in relation to the timing at which the heating element is stopped. It comprises a storage unit for storing a state, drives a motor drive unit based on the storage content of the storage unit, and after the timer unit starts accumulating time, outputs a time-up signal after a lapse of a predetermined time,
3. The cooking device according to claim 2, wherein the driving of the motor driving means based on the contents stored in the storage means is prohibited. 7. A timer means for starting integration of time in relation to a timing at which both the heating element and the frequency converter are stopped, and a timer means to start time integration of both the heating element and the frequency converter. Storage means for storing the output state of the temperature detection means, and driving the motor drive means based on the storage contents of the storage means, and after the timer means starts to accumulate time, a predetermined time has elapsed and the time is up. 3. The cooking device according to claim 2 , wherein when the signal is output, the driving of the motor driving unit based on the stored contents of the storage unit is prohibited.