JPH07272847A - Cooking apparatus with heater - Google Patents

Abstract

PURPOSE:To suppress temp. rise of electronic components and make the apparatus small by stopping the current feed to a heat emitting body when a cooling fan is operated and a specified temp. level is exceeded while the specific position of a cooking apparatus is in the specific condition, wherein the cooking apparatus is of such a type as using induction heating and a heating with a heat emitting body. CONSTITUTION:A cooking apparatus is equipped with two heating coils 55, 56 having inverter circuits 204, 214, a nickel-chromium heater 57, and a heater 64 for a heating chamber. When the temp. of a thermistor 121 installed under the nickel-chromium heater 57 exceeds 90 deg.C, or either circuit 204, 214 is put in the current fed condition, or when either heater 57, 64 is put in the current fed condition. then a photo triode AC switch coupler 111 is turned on so that fan motors 65, 66 are started. When the temp. of the thermistor 121 exceeds 105 deg.C, current feed to the nickel-chromium heater 57 is stopped so that electronic components are certainly prevented from destruction caused by thermal affection. Thus it is made practicable to carry out a high density mounting to permit the resultant cooking apparatus to be embodied in a small size.

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 by 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 that generates a high-frequency magnetic field to inductively heat a load pan and a resistance heating element such as a nichrome heater that heats by applying a current of a commercial frequency have been installed in the lower part of the same top plate. A heating cooker has been developed in which a heating chamber is provided under a heating coil and a resistance heating element such as a sheath heater is disposed therein.

A conventional heating cooker will be described below. FIG. 10 shows a conventional built-in type cooker having two heating burners for induction heating, one heating burner for a normal resistance heating element, and a heating chamber having 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, and heating coils 5a and 5b for induction heating and resistance heating for heating by applying a current of commercial frequency are heated therein. The nichrome heater 7 is disposed below the top plate 4 so as to face the top plate 4. The upper cooling fan 8 is provided on the front side of the bottom surface of the upper case 3 together with an intake port provided near the lower portion thereof, and a plurality of exhaust ports 9 are provided on the rear upper surface of the upper case 3. In addition, the opening 2 is formed on 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 unit 6, and is a component of an inverter for supplying a high frequency current to the heating coil 5b. A cooling fin 12 to which a transistor is attached, and a control board 1 on which control components are mounted.
3, and a main board 14 on which large-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,
A 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 for the lower cooling fan 10 and an upper cooling fan 8 are mounted.

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

The operation of the heating cooker configured as described above will be described below. First, when the power switch 19 is turned on and the input key provided on the operation unit 21 is pressed to operate any heating unit, the cooling fan 1
The 0 motor rotates. As a result, the outside air is sucked in through the intake port 11 and the cooling fins 12, 15 and the control board 1
3, 16 and the inverter board 14, and further the electronic parts mounted on the power supply board 17 and the like are cooled. The exhaust air after cooling the lower unit 2 is discharged 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.

Since the upper unit 1 is provided with the cooling fan 8 together with the intake port at the lower part thereof, the cooling air is sent to the heating coils 5a and 5b to be cooled, and the cooled cooling air is discharged from the exhaust port 9. To be 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 the connection line passing through the 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 minute signals flow through the connection line passing through the connector 24.

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

[0010]

However, in the above-mentioned conventional configuration, the high frequency generator such as the cooling fin 12 for cooling the inverter board 14, the control board 13 and the transistor, the low frequency power supply such as the power board 17, and the nichrome heater. Since the drive unit is arranged in the lower unit case 6, the number of connecting wires for connecting the upper and lower units is increased, the cost of wiring components is increased, and the work of connecting an electric wire through which a large current flows at the terminal block 23 at the time of installation is required. If it occurs, poor connection may cause overheating. Further, since electric components are concentrated in the lower unit case 6, the weight of the lower unit 2 is increased, and it is necessary to provide a stand for mounting the lower unit, which causes a problem that installation work is troublesome. There has been a problem that it is difficult to replace the heating cabinet 18 that is easily soiled, has a large degree of wear, and has a short service life.

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

A first object of the present invention is to solve the above-mentioned problems, and a resistance heating element is generated when the device is downsized by providing the frequency converter and the heating element control means in the same housing. It is to suppress the temperature rise of the electronic components in the device due to the influence of heat.

A second object of the present invention is to prevent the user from erroneously recognizing the protective function added in achieving the first object as a malfunction of the device.

A third object of the present invention is that immediately after the power switch is turned off or the driving of the frequency converter and the resistance heating element are both stopped, the internal heat of the resistance heating element causes an overshoot in the temperature of parts inside the machine body. If there is a risk of damage, the cooling fan will continue to operate to protect the components.

A fourth object of the present invention is, in addition to the third object, to more reliably suppress the overshoot temperature and prevent the cooling fan from operating longer than necessary.

A fifth object of the present invention is to prevent the user from erroneously recognizing the protective function added to achieve the third object as a malfunction of the device.

A sixth object of the present invention is, in addition to the above-mentioned fourth object, immediately after the power switch is turned off or the driving of the frequency conversion device and the resistance heating element are stopped together, they are continuously operated to prevent temperature rise. It is to reduce the operating time of the cooling fan as much as possible.

A seventh object of the present invention is, in addition to the above-mentioned sixth object, immediately after the power switch is turned off or the driving of the frequency converter and the resistance heating element are stopped, they are continuously operated to prevent temperature rise. It is to reduce the operating opportunities of the cooling fan as much as possible.

An eighth object of the present invention is, in addition to the above-mentioned fourth object, immediately after the power switch is turned off or the driving of the frequency conversion device and the resistance heating element are stopped, they are continuously operated to prevent temperature rise. To keep the operating time of the cooling fan constant.

A ninth object of the present invention is, in addition to the above eighth object, an operation opportunity of a cooling fan to be operated immediately after the power switch is turned off or the driving of the frequency conversion device and the resistance heating element are stopped together. To reduce as much as possible.

[0021]

In order to achieve the first object, the first means of the present invention is to provide a heating coil,
A frequency conversion device 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 electric parts. A power switch for switching connection and disconnection of the frequency converter or the heating element to a commercial power source; a motor for the cooling fan connected to the commercial power source side of the power switch; and a temperature sensor for controlling the temperature of the heating element. Temperature detection means for detecting the temperature of a portion that changes dependently and outputting a predetermined output signal on condition that the temperature exceeds at least the first temperature, and at least the temperature detection means outputs the predetermined output signal. Any one of the state of outputting, the state of driving the frequency conversion device, and the state of driving the heating element. Occurs, the motor driving means of the cooling fan is driven, and when the temperature of the temperature sensor reaches a second temperature higher than the first temperature, the driving of the heating element is stopped, or the heat generation is stopped. A heating cooker configured to reduce the heating output of the body is provided.

In order to achieve the above-mentioned second object, in the second means of the present invention, in addition to the above-mentioned first means, neither the heating element nor the frequency conversion device is driven, and at least the temperature detecting means is provided. Display device when it is in a state of outputting the predetermined output signal, or the temperature of the temperature sensor reaches a second temperature higher than a first temperature and stops driving the heating element, or Provided is a heating cooker having a display device for displaying when the heating output of a heating element is reduced.

In order to achieve the third object, the third means of the present invention is to generate heat by heating a heating coil, a frequency converter for supplying a high frequency current to the heating coil, and supplying a commercial frequency current. A heating element, a heating element control means for controlling energization of the heating element, a cooling fan for cooling electric parts, and a power switch for switching connection and disconnection of the frequency conversion device or the heating element to a commercial power source, The temperature of the cooling fan motor connected to the commercial power source side of the power switch and the portion that changes depending on the temperature of the heating element is detected, and a predetermined temperature is exceeded on condition that the temperature exceeds a predetermined temperature. A memory that includes temperature detecting means for outputting a signal, and stores and outputs a predetermined output signal according to the state of the output signal of the temperature detecting means at a predetermined time point. A step, at least one of the state in which the storage means outputs the predetermined signal, the state in which the frequency conversion device is driven, or the state in which the heating element is driven occurs. A heating cooker configured to drive a motor driving means of a cooling fan.

In order to achieve the above-mentioned fourth object, the fourth means of the present invention comprises a timer means in addition to the above-mentioned third means, and a predetermined signal output from the storage means is output. A heating cooker having a period set by the timer means is provided.

In order to achieve the above fifth object, the fifth means of the present invention is, in addition to the third means, at least the frequency converter and the heating element are not driven, and the storage means has a predetermined configuration. Provided is a cooking device provided with a display device that outputs an output signal to display or notify when the cooling fan is in an operating state.

In order to achieve the sixth object, the sixth means of the present invention, in addition to the fourth means, starts integration of time in relation to the timing at which the heating element is stopped. The timer means and the 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, the motor driving means is driven based on the stored contents of the storage means, and the timer is provided. A heating cooker configured to prohibit the driving of the motor driving means based on the stored contents of the storing means when the means outputs a time-up signal after a lapse of a predetermined time after starting the integration of time.

In order to achieve the above-mentioned seventh object, the seventh means of the present invention, in addition to the above-mentioned fourth means, starts the integration of time in relation to the timing at which the driving of the heating element is stopped. A timer means and a storage means for storing the output state of the temperature detection means in relation to the timing when the heating element and the frequency conversion device are both stopped are provided, and the motor drive means is provided based on the stored contents of the storage means. A heating cooker configured to prohibit the driving of the motor driving means based on the stored contents of the storing means when driven and the time-up signal is output after a lapse of a predetermined time after the timer means starts the integration of time. provide.

In order to achieve the above-mentioned eighth object, the eighth means of the present invention is, in addition to the above-mentioned fourth means, time related to the timing at which both the heating element and the frequency converter are stopped. And a 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 driving means based on the stored contents of the storage means. A heating cooker configured to prohibit the driving of the motor driving means based on the stored contents of the storing means when driven and the time-up signal is output after a lapse of a predetermined time after the timer means starts the integration of time. provide.

In order to achieve the above-mentioned ninth object, the ninth means of the present invention is, in addition to the above-mentioned fourth means, a time related to the timing at which both the heating element and the frequency conversion device are stopped. And a 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 conversion device are driven and stopped. The motor driving means is driven on the basis of the above, and when the timer means starts integration of time and outputs a time-up signal after a lapse of a predetermined time, the driving of the motor driving means based on the stored contents of the storing means is prohibited. And a heating cooker are provided.

[0030]

When the frequency converter is driven or the heating element is driven by the first means, the motor driving means of the cooling fan is driven, so that the heating element or the heating coil is energized. When it is in the air, it inhales from the outside to cool the heating element control means or the parts of the heating coil or frequency converter, and the heat received from the heating element or the heat generated by the heating element is discharged from the inside of the housing to raise the temperature of the parts. On the other hand, even if the power switch is turned off or the power switch is turned on, the cooling fan is stopped if all the heating sources are turned off, so that the chance of moving the cooling fan can be reduced.

Further, the temperature sensor is provided with a temperature detecting means for detecting the temperature of a portion which changes depending on the temperature of the heating element and outputting a predetermined output signal on condition that the temperature exceeds at least the first temperature. , At least when the temperature detecting means outputs a predetermined output signal, it drives the motor driving means of the cooling fan connected to the commercial power source side of the power switch, so that the atmosphere or parts affected by the heat generated by the heating element When its own temperature exceeds a specified temperature, the cooling fan will continue to operate automatically even if the power switch is turned off, or if the power switch is turned on and the heating sources such as the heating element and frequency converter are all de-energized. If the heating element with a large heat capacity has a high temperature, the heating element or parts around the heating element can be Preheat the continued to exhaust to the outside of the,
It is possible to prevent thermal destruction of the electronic component due to overshoot of the temperature of the electronic component that occurs immediately after the cooling fan is stopped.

Further, when the second temperature is reached, the driving of the heating element is stopped or the heating output of the heating element is reduced, so that the temperature of the heating element causes the temperature of the parts to be excessive. Even if the temperature rises, the temperature can be quickly lowered, and at that time, since the frequency converter is not stopped or the output is not suppressed at the same time, the inconvenience that cooking cannot be performed at all can be eliminated. Further, since the second temperature is set higher than the first temperature, the temperature of the temperature sensor always exceeds the first temperature when the temperature of the temperature sensor reaches the vicinity of the second temperature. At that time, turn off the power switch or leave the power switch on to stop driving all the heating sources such as the heating element and the frequency conversion device. Even if the cooling fan is continuously driven and there is no overshoot of the internal temperature, the temperature of the temperature sensor exceeds the second temperature due to the overshoot, and immediately after that the power switch is turned on to energize the heating element, but wait for a while. Without it, it will not happen that the power cannot be turned on.

Further, since there is no overshoot as described above, it is possible to raise the set value of the second temperature to a value corresponding to the state where the temperature reaches the vicinity of the temperature limit of the component. That is, it is not necessary to correspondingly lower the second temperature in consideration of the overshoot immediately after the cooling fan motor is stopped. If the second temperature can be raised, the difference between the temperature sensor temperature in the normal state and the second temperature can be increased, and the temperature of internal parts may decrease during normal operation due to reduced cooling capacity or partial blockage of the intake port. Even if the temperature rises to some extent, the sensor temperature does not reach the second temperature, so it is possible to reduce the chances of stopping the driving of the heating element or limiting the heating output, which is an inconvenient situation in which the heating element cannot cook. Can reduce the chance that

By the second means, the cooling fan may operate in the first means even when the power switch is turned off or the heating element and the frequency converter are not driven. When the temperature of the display device or the temperature sensor displayed when the temperature detecting means is in the state of outputting the predetermined output signal reaches the second temperature higher than the first temperature, or the driving of the heating element is stopped, or A display device for displaying the heating output of the heating element is displayed, and the user can be informed of the cause and the anxiety can be eliminated. In addition, when the heating / heating element is in use and the intake / exhaust port is blocked, driving of the heating element may be stopped or the heating output of the heating element may be reduced. You can know the cause.

When the frequency converter is driven or the heating element is driven by the third means, the motor driving means of the cooling fan is driven, so that the heating element or the heating coil is energized. While it is in the air, it inhales from the outside to cool the heating element control means or the electronic components of the heating coil and the frequency converter, and the heat received from the heating element and the heat generated by the heating element are discharged from the inside of the housing to remove the parts. You can suppress the temperature rise, on the other hand, not only when the power switch is turned off, even when the power switch is on,
When all of the above heating sources are turned off, the cooling fan stops, so that the opportunity to move the cooling fan can be reduced.

Further, an output at a predetermined time point of a 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 means for storing the content of the signal and outputting the signal in accordance with the stored content,
When at least the storage means outputs a predetermined output signal, the motor driving means of the cooling fan connected to the commercial power source side of the power switch is driven, so that the temperature of the portion that changes depending on the temperature of the heating element At a given time,
If the predetermined temperature is exceeded, the cooling fan can be continuously operated thereafter.

Therefore, even if the power switch is turned off, or if the power switch is turned on and the heating element and the frequency conversion device are both de-energized, 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 heating element is de-energized, the atmosphere detected by the temperature detecting means or the temperature of the component is When the temperature exceeds the predetermined temperature, the cooling fan can be continuously operated automatically until the temperature detected by the temperature detecting means becomes low. Therefore, even if the power switch is turned off when the heating element with a large heat capacity is high in temperature, or both the heating element and the frequency converter are de-energized, the residual heat from the heating element or parts around the heating element is continued to the outside. Thus, it is possible to prevent the thermal destruction of the electronic component due to the overshoot of the temperature of the electronic component which occurs immediately after the cooling fan is stopped.

Further, since the output state of the temperature detecting means at a predetermined time point is stored and the motor driving means is driven in accordance with the state, it is possible to ignore the predetermined output state of the temperature detecting means other than the predetermined time point. After the power switch is turned off, the heating element and the frequency converter are stopped, and the cooling fan is stopped, the temperature detected by the temperature detection means overshoots due to the stop of the fan motor. Temperature exceeds the predetermined temperature, the output state of the temperature detection means changes, and the cooling fan motor, which has stopped once, starts to move for a while even if the user is not doing anything, which causes an unnatural feeling to the user. You can get rid of things.

In the third means for solving the above-mentioned fourth problem, after the power switch is turned off or both the heating element and the frequency conversion device are stopped, the operation time of the cooling fan by the operation of the storage means is Since it is regulated by the timer means, it is possible to surely prevent the components from being destroyed due to the temperature overshoot due to the residual heat of the heating element, and the cooling fan does not continue to operate longer than necessary.

According to the fifth means, at least the frequency converter and the heating element are not driven, and the storage means outputs a predetermined output signal to display or give a notification when the cooling fan is in an operating state. In the third means, the cooling fan may operate even after the power switch is turned off or both the heating element and the frequency conversion device are de-energized. The cause can be known by the display device.

By the sixth means, the motor driving means is driven based on the stored contents of the storing 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. When the temperature detected by the temperature detecting means exceeds a predetermined temperature at a time set immediately before or immediately after the heating element is stopped or immediately after that, the output of the temperature detecting means is in 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 on and the heating element and the frequency conversion device are both de-energized, the cooling fan continues or is very small. Therefore, after the cooling fan has stopped, the output state of the temperature detecting means changes from "Lo" to "HI" for a while due to overshoot of the detected temperature. Then, there is no unnatural operation such that the cooling fan motor starts operating for a while (for example, 10 seconds later) after the cooling fan is stopped and the user does nothing.

When the timer means for starting the integration of time in relation to the timing at which the heating element is stopped is driven and a time-up signal is output after a lapse of a predetermined time after the start of integration of time, the contents stored in the storage means are stored. Since the driving of the motor drive means based on the above is prohibited, the power switch is turned off or the heating element and the frequency conversion device are both de-energized and continue to operate after a predetermined time elapses after the heating element is stopped. The cooling fan stops operating.

When the temperature detected by the temperature detecting means exceeds a predetermined temperature, only the heating element is stopped and the frequency converter is not stopped, the output signal of the temperature detecting means outputs a predetermined output state, for example. It becomes "Lo" and the storage means stores it and tries to drive the motor drive means, but 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 the time when the heating element is stopped or at the time when the heating element is stopped.

That is, if the frequency conversion device continues to be used 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 device is stopped. The cooling fan is continuously driven after the power switch is turned off or the frequency conversion device is stopped by the difference between and. When the operating time of the frequency conversion device after the heating element is stopped becomes longer than the time set by the timer means, the operation of the cooling fan is stopped at the same time when the frequency conversion device is stopped or the power switch is turned off.

Therefore, when the heating element is stopped first and then the power switch is turned off or the frequency converter is stopped, the time during which the cooling fan continuously operates can be shortened.

By the seventh means, the motor drive means is driven based on the stored contents of the storage means which stores the output state of the temperature detection means in relation to the timing when the heating element and the frequency conversion device are both stopped. Due to the configuration, the temperature detected by the temperature detecting means exceeds the predetermined temperature at the time when the heating element and the frequency conversion device are both stopped or immediately before, immediately after, or at a time set in relation to the time. And the output of the temperature detection means becomes a predetermined state, the storage means stores the state, and the motor drive means is driven to cool the power switch or even if the heating element and the frequency conversion device are both de-energized. The fan runs continuously or after a very short stop and then continues.

That is, unlike the sixth means, the motor driving means is controlled based on the stored contents of 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 conversion device are stopped. Since it is configured to be driven, the heating element is stopped before the frequency conversion device, and even if the output state of the temperature detection means is the state of driving the cooling fan at that time, the frequency conversion device is stopped with a delay thereafter. At that time, unless the temperature inside the machine is lowered and the output state of the temperature detection means is in a state of driving the cooling fan, the cooling fan does not continue to operate. Therefore, as compared with the sixth 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.

By the eighth means, unlike the sixth means, the timer means for starting the integration of time in relation to the timing at which both the heating element and the frequency conversion device are stopped after the start of integration of time. When a predetermined time has elapsed, a time-up signal is output to prohibit the driving of the motor drive means based on the stored contents of the storage means.
When the power switch is turned off or the power switch is turned on, the cooling fan that continues to operate after the heating element and the frequency conversion device are both de-energized stops operating.

Therefore, when the temperature detected by the temperature detecting means exceeds a predetermined temperature, only the heating element is stopped and the frequency conversion device continues to operate.
In the sixth means, the operating time of the cooling fan motor after the operation of the frequency converter is stopped differs depending on the relationship between the stop timing of the heating element and the stop timing of the frequency converter, but in this case, it is constant regardless of that. Becomes

By the ninth means, the motor drive means is driven based on the stored contents of the storage means for storing the output state of the temperature detection means in relation to the timing when both the heating element and the frequency conversion device are stopped. Since the configuration is the same as the seventh means, compared to the sixth means, there is less chance that the cooling fan is continuously driven after the power switch is turned off and the frequency conversion device is stopped. be able to. Further, when the timer means for starting the integration of time in relation to the timing at which both the heating element and the frequency conversion device are stopped is driven and a predetermined time elapses after the start of integration of time, the time-up signal is output. Since the driving of the motor drive means based on the stored contents is prohibited, the operating time of the cooling fan motor after the power switch is turned off or the operation of the heating element and the frequency conversion device is stopped, as in the eighth means. It is possible to make it constant regardless of the relationship between the stop timing of the heating element and the stop timing of the frequency converter.

[0051]

【Example】

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

In FIG. 1, the main body is composed of an upper unit 26 and a lower unit 27, and the upper unit 26 has an upper unit case 28 made of an iron plate and a top plate 2 made of ceramic.
9 is fixed by a frame-shaped top frame 30 and formed in a box shape, and a rear cover 31 having a plurality of holes for intake and exhaust is provided on the upper part of the intake and exhaust ports at the rear. Top 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 part. The lower unit 27 is provided with a power switch 33, an operation section 34 in which input keys are arranged, a display section 35, and a heating door 36 on the front surface of a lower unit case 32 made of a substantially U-shaped iron plate. A heating cabinet 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 section 34 and the display section 35, and the signal line 42a connected by a connector on the wiring board is connected by the connector 40 to the signal line 42b extending from the upper unit 26. It The connection line 43 is connected to the power switch 33 and is connected to the connection line 44 extending from the upper unit 26 by the connector 41. The engaging portion 45 and the engaging portion 4 are provided on both sides of the bottom surface of the upper unit case 28.
6 is provided, and the upper side plate of the lower unit case 32 is bent inward to provide an engaging portion 47 and an engaging portion 48.

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

In FIG. 3, the heating coil 56 is fixed on the heating coil base 56b made of resin, the nichrome heater 57 is fixed on the bottom surface of the case 57a made of an inorganic material having a heat insulating effect, and the case 57a is further provided with aluminum at the bottom thereof. A heat insulating plate 57b formed of a plate is provided, and a power supply substrate 52 on which parts such as the filter coil 102 and the filter coil 105 are placed 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 at the rear part, and the partition plate 61 is provided with a plurality of intake holes or exhaust holes correspondingly.

FIG. 4 is an overall circuit block diagram, in which the power supply board 52, the inverter board 50, the inverter board 51, and the operation board 62 are surrounded 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 board 5
2, the filter coil 102 and the filter capacitors 103 and 104 connected between each power supply line and the housing are connected between the power supplies on the side of the inverter board 50 as seen from the switch 33, and the side of the inverter board 51 as seen from the switch 33. A filter coil 105, filter capacitors 106 and 107 connected between each power supply line and the case are connected between the power supplies. Between the connection point of 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, a series circuit of the heating chamber heater 64 and the relay 110 is connected in parallel via a triac 108. The circuits are connected.

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

The fan motor drive circuit 117 inputs the signals of the phototransistors 118a, 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.
The signal is output to the fan motor drive circuit 117 according to the signal of. Display circuits 119 each including a light emitting diode
a and a display circuit 119b are provided, the display circuit 11
9a lights the light emitting diode in response to the input signal from the fan motor drive circuit 117, and the display circuit 119b lights 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 terminal of the transformer 202 and the input terminal of the rectifier 203 are connected to the input terminal via the fuse 201. Has been done. An inverter circuit 204 that supplies a high frequency current to the heating coil 55 is connected to the output terminal of the rectifier 203. The control circuit 205 is a circuit that drives the switching elements of the inverter circuit 204 and controls the output. The secondary winding of the transformer 202 is connected to the DC power supply circuit 206, and the DC power supply circuit 206 includes the control circuit 205 and the operation board 6.
A DC power supply is supplied to the input circuit 301 provided in the No. 2. The control circuit 205 also includes a phototransistor 118.
The drive signal of b is output.

The structure of the inverter board 51 is the same as that of the inverter board 50, and a description thereof will be omitted. Operation board 6
The output signal of the second 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 is a phototransistor 303
And an output signal to the phototransistor 304, and the output signal from the phototransistor 303 is transmitted to the relay drive circuit 115.
The output signal of the phototransistor 304 is output to the relay drive circuit 116. The input circuit 302 is a gate-T of the triac 108.
Triac coupler 12 connected between two via a resistor
A drive signal of 0 is output.

The operation of the induction heating cooker configured as described above will be described. When the device is installed on a sink or the like in FIG. 1, 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 by the top frame 30 on the top plate surface. In that state, the lower unit 27 is attached to the engaging portion 4 of the upper unit 26 from the front of the hole provided on the front surface of the sink or the like.
5, 46 and the engaging portions 47, 48 of the lower unit 27 are inserted so as to engage with each other, and the lower unit 2 is inserted into the upper unit 26.
The lower unit can be fixed so that 7 can be suspended. The connector 40 and the connector 41 can be connected to each other during the insertion of the lower unit.

When the power switch 33 is turned on and the input key of the operation unit 34 is pressed, the inside of the upper unit 26 shown in FIG.
A fan motor drive circuit provided on the power supply board 52 drives the cooling fan 53 and the cooling fan 54 at the same time, and each cooling fan is exposed to the outside through a plurality of holes provided in the intake duct 58 and the partition plate 61 in front of the intake duct 59. Inhale each of the air. The air blown from the outlets of the cooling fan 53 and the cooling fan 54 is the inverter board 50 and the inverter board 5.
After cooling the heat-generating components and the electronic components on each inverter board 50 by the guides provided on the respective ones, it is folded back at the center to cool the electronic components on the power supply board 52 to be provided on the wall surface in front of the exhaust duct 60. The air is exhausted through the exhaust holes through the exhaust duct to the outside of the upper room.

Inverter board 50 and inverter board 51
When the inverter circuit of No. 2 operates, a high frequency current is supplied to the heating coil 55 and the heating coil 56, a high frequency magnetic field is generated from each heating coil, and the patterns 37 and 38 of FIG.
The pot placed on top of it heats up. 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 in the surroundings. However, as shown in FIG. 3, an aluminum plate is formed below the nichrome heater 57 for thermal insulation. Since the heat insulating plate 57b formed by the above is provided, and this blocks the magnetic field generated by the heating coil 55 and the heating coil 56, the magnetic field strength below it becomes small.

On the other hand, an obstacle plate 57b of the nichrome heater 57
Since the components of the commercial power supply potential such as the filter coil 102 and the filter coil 105 are mounted on the power supply substrate 52 in the lower part of the above, the strength of the magnetic field generated by the heating coil 50 and the heating coil 51 becomes small as described above, It is possible to prevent high-frequency noise from being superimposed on the commercial power source potential and leaking to the commercial power source 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.
The voltage of 3 is rectified by the rectifier 203 and the inverter circuit 20
A DC voltage is supplied to 4. When the 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, 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 the resonance of the resonance capacitor and the heating coil 55. The transformer 202 supplies AC voltage to the DC power supply circuit 206,
The DC power supply circuit 206 converts this into a smoothed direct current and supplies it to the control circuit 205 and the input circuit 301. Since the primary winding of the transformer 202 is connected to the power 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 operation of the circuit block of the inverter board 51 that drives the heating coil 56 (corresponding to the heating pattern 38) is also the same.

When the ON / OFF key of the operation unit 34 (FIG. 1) for driving the nichrome heater 57 (corresponding to the heating pattern 39 of FIG. 1) is pressed, the input circuit 302 of the operation board 62 accepts this and a delay of 2 seconds. After a lapse of 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 the drive signal of the triac coupler 120 about 50 milliseconds after the drive signal of the relay 109 is output, and the triac 108 becomes conductive.

Heater heater 6 in operation unit 34 (FIG. 1)
When the ON / OFF key for driving 4 is pressed, the input circuit 302 of the operation board 62 accepts this and outputs the drive signal of the relay 116 to the relay drive circuit 116 via the phototransistor 304 after a delay time of 2 seconds, and the relay 110 is turned on. To drive. The input circuit 302 outputs the drive signal of the triac coupler 120 about 50 milliseconds after the drive signal of the relay 116 is output, and the triac 108 becomes conductive.

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 is sent 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 receives the drive signal via the phototransistor 118a.
When a drive signal is sent to the fan motor drive circuit 117 and any one of these drive signals is input, the phototriac coupler 111 is driven and the fan motor 65 and the fan motor 66 operate.

A thermistor 121 is mounted on the power supply board 52, and when the temperature of the thermistor 121 rises above about 90 ° C., 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.
Also, it is possible to prevent the electronic parts from being overheated and destroyed due to the temperature overshoot due to the residual heat of the heating chamber heater 64 or the heating chamber 49 (FIG. 1).

The fan motor drive circuit 117 inputs the fan motor drive signal output from the temperature detection circuit 122 and does not input the drive signal of the phototriac coupler 111 from the phototransistor 118a or the phototransistor 118b. The drive signal is output to. When the display circuit 119a receives this drive signal, it turns on the light emitting diode. Therefore, the temperature of the thermistor 121 is high immediately after the power switch 33 is turned on and the power supply to all the heating means is stopped, or immediately after the power switch is turned off during use, and the fan motor 6
When the circuits 5 and 66 continue to operate, the display circuit 119 lights up, and the user can know the reason why the fan motors 65 and 66 are still operating after the power switch is turned off.

The temperature of the thermistor 121 is about 105.
When the temperature rises above ° 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 parts from overheating. The temperature detection circuit 122 outputs the above-mentioned prohibition signal to the relay drive circuit 115 and at the same time outputs a drive signal to the display circuit 119b, and the display circuit circuit 119b turns on the light emitting diode when this signal is input, so that the user can use the nichrome heater 57. It can be known that the cause of the operation stop of is due to the abnormal temperature rise of the 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 winding is connected to the power supply side of the power switch 33, the fuse 201, and the fuse 202, the DC power supply is continued even if these are cut off.

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

The temperature of the thermistor 121 is about 105.
When the temperature exceeds ℃, since the heating operation of the nichrome heater 57 is stopped, it is possible to reliably prevent the destruction of the internal parts due to the heat effect of the nichrome heater 115.

As described above, the temperature detected by the thermistor 121 is provided with a two-step judgment standard, and the function of protecting the parts 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 of occurrence of a situation that is extremely inconvenient for the user, such as the above.

Further, when the nichrome heater 57, the heating heater 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. , A display circuit 119a for lighting a light emitting diode
Further, since the temperature detection circuit 122 is provided with the display circuit 119b that is turned on when the operation of the nichrome heater 57 is prohibited, the user knows that the protection operation function of the temperature detection circuit 122 is operating. Can
It is possible to eliminate the risk of being mistaken for a malfunction and giving the user a feeling of anxiety.

Further, according to the structure of this embodiment, the upper unit 2
Since I was able to concentrate most of the electronic parts 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 operation of suspending the lower unit 27 on 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 AC motors in series with the phototriac coupler 111 to the commercial power source side of the power switch 33, but 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.

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

In the above embodiment, the frequency conversion device is 2
Although the heating cooker has one piece, one nichrome heater, and one heating cabinet heater, the same effect can be obtained with, for example, one frequency converter and one heating cabinet heater, and the combination can be changed appropriately. The same effect can be obtained as long as it is a heating cooker having at least one or more frequency converters and a heating element heated by one or more commercial frequency heating sources.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

In FIG. 5, the fan motor drive circuit 402 connected between the power supply terminals on the AC power supply 63 side as viewed from the power supply switch 33 is a storage circuit 403 and a timer circuit 404.
And the output signal of the input circuit 406 are input to the fan motor 4
Drive twelve. The thermistor 400 is the heater 41
It is attached to the wall of the heating cabinet containing 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 the temperature storage circuit 40.
Input to 3.

The input circuit 406 inputs a heating command and an output setting command by a tact switch or the like, and sends an output signal to the fan drive circuit 402, the relay drive circuit 405, the inverter control circuit 407 and the timer circuit 404. The input circuit 406 inputs the signal from the power switch on / off detection circuit 413 and outputs the signal to the memory 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. Turn on the power switch 33 and use the tact key of the input circuit 406 to heat the heating coil 40.
When the drive command of No. 9 or the command of the heating 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 this 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, causes the inverter circuit 408 to oscillate, and outputs a signal to the relay drive circuit 405 when a drive signal for the heating chamber heater 411 is input. To feed electricity to the roaster heater.

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

The temperature detection circuit 401 periodically measures the temperature of the thermistor 400, and the temperature of the thermistor 400 is about 1
When the temperature reaches 00 ° C., an arrival signal is output to the memory circuit 403, and when the temperature does not reach the temperature, a non-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 reach signal is output, When the energization stop determination signal is input from the input circuit 406, the arrival signal is stored and the drive signal is output to the fan motor drive circuit 402, so that the fan motor 412 is driven. That is, the memory circuit 4
03 is outputting a drive signal to the fan motor drive circuit 402, the input signal from the temperature detection circuit 401 is
When the arrival signal changes to the non-arrival signal, the storage circuit 403
Unconditionally stops outputting the drive signal to the fan motor drive circuit 402, but conversely, even if the input signal from the temperature detection circuit 401 changes from a non-arrival signal to a reach signal, energization is stopped from the input circuit 406. 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 ON / OFF of the power switch 33 and driving / stopping states of the heater heater 411. The timer circuit 404 resets the integrated value of the output signal and time when the driving state signal of the heating chamber heater 411 is input, and stops the cumulative operation. When the OFF state signal of the power switch 33 or the stop state signal of the heating chamber heater 411 is input. A time-up signal is output to the fan motor drive circuit 402 when about 10 minutes have elapsed after starting the time integration operation. 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, or when the power switch 33 is turned on and the heating coil 409 and the heating chamber heater 411 are both de-energized. Since the storage circuit 403 that stores the content of the output signal of the temperature detection circuit 401 in and outputs the signal in accordance with the stored content is provided,
The temperature of the thermistor 400 rises during the time when the power switch 33 is switched from on to off or after the power switch 33 is in the on state and the heating coil 409 and the heating chamber heater 411 are both de-energized.
It is possible to prevent the unnatural phenomenon of starting to work.

Even when the above timer circuit 403 is omitted, the above effect can be obtained, but it continues after the power switch 33 is turned off or all the heat sources are turned off while the power switch 33 is on. The fan motor 412 that has operated in this way stops when the signal output from the temperature detection circuit 401 changes from the arrival signal to the arrival signal, and the time until it stops is when the decrease in the internal temperature is slow. It may take a long time.

As shown in the above embodiment, when the timer circuit 403 is added, the power switch 33
When about 10 minutes elapse from the time when the heating cabinet heater 411 is turned off and the heating cabinet heater 411 is de-energized, the timer circuit 403 prohibits the fan circuit 412 from being driven by the memory circuit 403. It is possible to reliably prevent the chute, and it is possible to prevent the fan motor 412 from operating for an unnecessarily long time.

Even when the timer circuit 403 is omitted, the above effect can be obtained, but it continues after the power switch 33 is turned off or all the heat sources are turned off while the power switch 33 is on. The fan motor 412 that has operated in this way stops when the signal output from the temperature detection circuit 401 changes from the arrival signal to the arrival signal, and the time until it stops varies depending on the internal temperature state.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

In FIG. 6, blocks having the same functions as those in FIG. 5 are assigned the same numbers and their explanations are omitted. Differences from FIG. 5 will be described below. The memory circuit 403 in FIG. 5 is configured by the flip-flop IC 415 in FIG.
The timer circuit 404 is composed of 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. Similar to FIG. 4, an inverter circuit 428 for supplying a high frequency current to the heating coil 427 and its control circuit 433, an inverter circuit 430 for supplying a high frequency current to the heating coil 429 and its control circuit 434 are provided, and a photo coupler 435 is provided. Control circuit 433 via photo coupler 436
The output signal of the control circuit 434 is 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 that drives 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 electrode of the DC power supply (hereinafter referred to as VDD
(Referred to as “”), a resistor 421, a resistor 422, and an emitter-collector of the transistor 420 are connected in series.
The base of the transistor 420 is a flip-flop IC4
15 output terminal (Q) is connected via a resistor 417,
The data input terminal (D) and the set input terminal (S) of the flip-flop IC415 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 photocoupler 435 and the photocoupler 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
The system for sending the output signal to 33 and the system for sending the 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. Further, when the power switch 33 is turned off, the input circuit 442, the control circuit 433, and the control circuit 4
The control power supply of 34 is cut off, and the photocoupler 44
3, the photo coupler 435 and the photo coupler 436 are turned off.

The display circuit 437 inputs 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 signals.

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. An AC power supply voltage is applied to the fan motor 412 to rotate. Similarly, even if a heating signal is output from the input circuit 442 to the control circuit 434, the fan motor 412 rotates. In addition, the input circuit 442 outputs the drive signal to the photocoupler 443 and outputs the drive signal to the control circuit 433.
The drive command of 35 is output. Therefore, from the input circuit, the heating heater 411 and the heating coil 4 are
When a heating command is output to at least one of 27 and the heating coil 429, the fan motor 412 rotates.

When 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 IC415 becomes HI, and the reset input terminal (R).
Is fixed at 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 turned off, the rotation of the fan motor 412 is stopped at the same time when the transistor 439 is turned 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 IC415 becomes Lo, so that the output terminal (Q) of the flip-flop IC415 has The level of the data input terminal (D) is output when the level of the clock input terminal (CK) rises, and the level of the clock input terminal (CK) changes 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 heating heater 411 is turned from the energized state to the off state, that is, when the transistor 425 is turned from the on state to the off 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 IC415 are Lo, the output terminal (Q) of the flip-flop IC415 will be 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, the fan motor 412 will rotate even if the transistor 439 is turned off. That is, the fan motor 412 rotates when the heating coil 427, the heating coil 429, and the heating chamber heater 411 are not all driven, or even when the power switch 33 is turned off.

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 measures the time. After about 10 minutes have elapsed, the measurement operation is stopped and the output terminal (OUT) level changes from HI to L.
It becomes o. At this time, since the base of the transistor 438 is fixed to Lo through the diode 419, the transistor 4
Even if 20 is on, the transistor 438 does not turn on.

Therefore, the phototriac coupler 440 is driven by the transistor 438 and the fan motor 412 is rotated because the temperature of the thermistor 400 is 1 when the heating heater 411 is de-energized.
This is the case where the temperature is higher than 00 ° C., and it is about 10 minutes after the energization of the heating chamber heater 411 is stopped.

Further, the display circuit 437 is 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 this embodiment, the output state of the temperature detection circuit 401 at the time when the heating chamber heater 411 is switched from the energized state to the non-energized state is stored in accordance with the output state of the flip-flop IC 415. , The timer IC 416 that drives the fan motor 412 and starts the integration of time from the time when the heating heater 411 is switched from the energized state to the non-energized state, drives the fan motor 412 when about 10 minutes have elapsed after the start of the time accumulation. Is prohibited, 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, and the internal temperature of the equipment does not overshoot due to the residual heat of the heating chamber heater 411, so that electronic components are not thermally destroyed.

Further, since the timer IC 416 starts integrating the time almost in synchronism with the deenergization of the heating chamber heater 411, the heating coil 427 after the deceleration of the heating chamber heater 411 is energized.
If the heater coil 429 is continuously energized, the timer I
C continues the time integration 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 heating heater 411 is turned off until the power switch 33 is turned off, or the power switch 33 is turned off. The operating time from turning on to turning off all heating sources is less than about 10 minutes,
The operation time of the fan motor 412 after the power switch 33 is turned off can be shortened. In addition, the heating chamber heater 411
After the fan motor 412 is turned off 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, and the output of the temperature detection circuit 415 becomes Lo, and the fan stopped. It is possible to prevent the unnatural phenomenon that the motor 412 starts to operate again.

(Fourth Embodiment) A fourth embodiment of the present invention will be described below with reference to the drawings. 7 is different from FIG. 6 in that the resistor 446 connected between VDD and the common potential, the collector-emitter series connection circuit of the transistor 447, the base of the transistor 447, and the output side transistors of the photocouplers 435 and 436 are connected. A resistor 448 connected between the emitter terminals is provided to connect the clock input terminal (CK) of the flip-flop IC415 and the collector of the transistor 447. Components or circuit blocks designated by the same reference numerals as those in FIG. 6 have similar functions.

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 because the data terminal (D) and the set input terminal (S) of the flip-flop IC 415 are Lo and the photo couplers 435, 436 have This is the time when the emitter of the output side transistor changes from HI to Lo.

Therefore, as in the third embodiment, the power switch 33 is turned off or the heating coil 427 is used.
When any one of the heating coil 429 and the heating chamber heater 411 is energized to be in a non-energized state, the transistor 439 is turned off to stop the driving of the fan motor 412, but the transistor 447 is turned from on to 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 to continue driving the fan motor 412. After that, the time when the fan motor 412 operates is determined by the timer IC 416 as in the third embodiment, and the fan motor 412 operates for about 10 minutes after the driving of the heating chamber heater 411 is stopped.

As described above, according to the present embodiment, the temperature detection circuit 401 at the time when the heating heater 411, the inverter 428, and the inverter 429 are all stopped driving.
The fan motor 412 is driven by the output signal of the flip-flop IC 415 that stores the output state of the timer IC 416, and the timer IC 416 starts time integration from the time when the heating heater 411 stops driving, and when about 10 minutes elapse, the timer I
Since C416 is configured to prohibit the driving of the fan motor 412 by the output signal of the flip-flop IC415, the same effect as that of the third embodiment can be obtained, and
Compared with the third embodiment, there are the following advantages.

That is, in the third embodiment, the heating chamber heater 41 is used.
Since the fan motor 412 was driven by storing the output state of the temperature detection circuit 401 at the time point 1 when the energization was stopped, if the heating heater 411 is deenergized by the inverter 428 or the inverter 429 before, When the power switch 33 is turned off, the temperature of the thermistor 400 has dropped, and the output of the temperature detection circuit 401 is HI.
However, the fan motor 412 may be continuously driven, but such a situation does not occur in the configuration of the present embodiment. Therefore, it is possible to reduce the chances of the fan motor 412 continuously operating after the power switch 33 is turned off.

(Embodiment 5) A fifth embodiment of the present invention will be described below with reference to the drawings. 8 is different from FIG. 6 in that the resistor 450 connected between VDD and the common potential, the collector-emitter series connection circuit of the transistor 449, the base of the transistor 449, and the output side transistors of the photocouplers 435 and 436 are connected. A resistor 451 connected between the emitter terminals is provided for the timer IC 4
The sixteen reset input terminals (R) are connected to the collector of the transistor 449. Components or circuit blocks designated by the same reference numerals as those in FIG. 6 have similar functions.

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

As described above, according to this embodiment, the flip-flop IC 4 which stores the output state of the temperature detection circuit 401 at the time when the heating heater 411 is stopped driving.
The output signal of 15 drives the fan motor 412,
Heater heater 411, inverter 428, and inverter 4
The timer IC 416 starts time integration from the time when all 29 drive stop is made, and after about 10 minutes, the timer IC 416 causes the above flip-flop IC to be integrated.
Since the configuration is such that the drive of the fan motor 412 by the output signal of 415 is prohibited, the same effect as that of the third embodiment can be obtained, and there are the following advantages over the third embodiment.

That is, in the third embodiment, the heating chamber heater 41 is used.
When the power supply stop time of 1 precedes the stop time of another heating source or the time of turning off the power switch, the operation time of the fan motor 412 after that varies depending on the preceding time. However, in the configuration of the present embodiment, such a situation does not occur, and the time from the reset release of the timer to the time up can be kept constant for about 10 minutes.

(Embodiment 6) A sixth embodiment of the present invention will be described below with reference to the drawings. 9 is different 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. Parts or circuit blocks designated by the same reference numerals as those in FIG. 8 have similar functions.

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 temperature of the thermistor 400 exceeds about 100 ° C. when the transistor 449 changes from on to off, and thereafter the timer The operation of the fan motor 412 continues for about 10 minutes until the IC 416 times out and the output terminal (OUT) becomes Lo.

As described above, according to the present embodiment, the temperature detection circuit 401 at the time when the heating chamber heater 411, the inverter 428, and the inverter 429 are all stopped driving.
The output signal of the flip-flop IC 415 which stores the output state of the fan I drives the fan motor 412, and the heater I 411, the inverter 428, and the inverter 429 are all driven and stopped by the timer I.
The timer IC 416 is configured to prohibit the drive of the fan motor 412 by the output signal of the flip-flop IC 415 after about 10 minutes have elapsed since the C 416 started to integrate the time. Therefore, the same effect as in FIG. 8 is obtained, and Compared with FIG. 8, there are the following advantages.

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

[0120]

As described above, the first means of the present invention detects the temperature of a portion that changes depending on the temperature of the heat generating element, and the predetermined temperature is set at least when the temperature exceeds the first temperature. At least one of a state in which a temperature detection unit that outputs an output signal is provided and at least the temperature detection unit outputs a predetermined output signal, a state in which the frequency conversion device is driven, or a state in which the heating element is driven Occurs, the motor driving means of the cooling fan is driven and the temperature of the temperature sensor is higher than the first temperature.
When the temperature of the heating element is reached, the driving of the heating element is stopped or the heating output of the heating element is reduced. It is possible to prevent the parts from failing due to the temperature rise. In addition, in order to prevent the temperature from rising, the opportunity or degree of suppressing the energization of the heating element or the frequency conversion device or suppressing the output is reduced,
The chance of inconvenience of not being able to cook can be reduced.

The second means of the present invention is a display device for displaying when the heating element and the frequency conversion device are not driven, and at least the temperature detection device is in a state of outputting a predetermined output signal, Alternatively, since the temperature sensor reaches a second temperature higher than the first temperature to stop the driving of the heating element or to reduce the heating output of the heating element, a display device for displaying is provided. When the function is activated, it is possible to prevent the user from erroneously determining it as a failure.

The third means of the present invention further comprises storage means for storing the content of the output signal of the temperature detecting means at a predetermined time point and outputting a signal in accordance with the stored content, at least the storage means having a predetermined value. When any one of the state of outputting a signal, the state of driving the frequency converter, and the state of driving the heating element occurs, the motor driving means of the cooling fan is driven, so turn off the power switch. After that, or even if all the heat sources are turned off and the cooling fan normally stops operating, the cooling fan can be driven and
Turn off the power switch or turn off all the heat sources from the power-on state, and once the cooling fan has stopped, eliminate the unnatural operation of starting the cooling fan after a while without doing anything. be able to.

Further, the fourth means of the present invention is provided with a timer means, and since the period during which the predetermined signal outputted from the storage means is outputted is set by the timer means, 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 turning off the heating source can be set to the required time.

The fifth means of the present invention is a display or notification 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 device is provided, it is possible to prevent the user from deciding that the cooling fan is operating as a malfunction even after the power is turned off or all the heating sources are de-energized.

The sixth means of the present invention drives the motor driving means on the basis of the stored contents of 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, thereby generating heat. When the timer means for starting the integration of time in relation to the timing at which the body is stopped being driven outputs a time-up signal after a lapse of a predetermined time after starting the integration of time, the motor drive means based on the stored contents of 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 seventh means of the present invention is to drive the motor drive means on the basis of the stored contents of the 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 conversion device are stopped. When the timer means that starts the integration of time in relation to the timing at which the heating element is stopped is started and the time-up signal is output after a predetermined time has elapsed after the start of integration of time, the stored content of the storage means is changed. Since the drive of the motor drive means based on the prohibition is prohibited, it is possible to reduce the chance that the cooling fan continuously operates after the power switch is turned off or after all the heating sources are de-energized without deteriorating the cooling performance. it can.

The eighth means of the present invention drives the motor driving means on the basis of the stored contents of the storing means for storing the output state of the temperature detecting means in relation to the timing at which the heating element is stopped driving, thereby generating heat. When the timer means that starts the integration of time in relation to the timing at which both the body and the frequency conversion device are stopped is driven and a time-up signal is output after a predetermined time has elapsed, the contents stored in the storage means Since the drive of the motor drive means based on the above 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 have been de-energized can be made constant.

The ninth means of the present invention is the motor driving means based on the stored contents of the storing 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 conversion device are stopped. When the timer means that starts the integration of time in relation to the timing at which both the heating element and the frequency conversion device are stopped is driven and a time-up signal is output after a predetermined time has elapsed,
Since the driving of the motor drive means based on the stored contents of the storage means is prohibited, the chances of the cooling fan continuing to operate after the power switch is turned off or after all heating sources have been de-energized are reduced, and the operating time Can be constant.

[Brief description of drawings]

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

FIG. 2 is an internal plan view of the heating cooker.

FIG. 3 is a cross-sectional view of the main parts of the heating cooker.

FIG. 4 is a circuit block diagram of the heating cooker.

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 heating cooker 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 heating cooker according to a fifth embodiment of the present invention.

FIG. 9 is a circuit block diagram of a heating cooker 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)

Claims (9)

[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 means for controlling energization of the heating element. A cooling fan for cooling electric parts, a power switch for switching connection and disconnection of the frequency converter or the heating element to a commercial power source, and a motor for the cooling fan connected to a commercial power source side of the power switch, The temperature sensor includes a temperature detection unit that detects a temperature of a portion that changes depending on the temperature of the heating element and outputs a predetermined output signal on condition that the temperature exceeds at least a first temperature. A state in which the detection means outputs the predetermined output signal, a state in which the frequency conversion device is driven, or a state in which the heating element is driven. When any one of the states occurs, the motor driving means of the cooling fan is driven, and when the temperature of the temperature sensor reaches a second temperature higher than the first temperature, A heating cooker configured to stop driving or reduce the heating output of the heating element. 2. A display device for displaying when both the heating element and the frequency conversion device are not driven, and at least the temperature detection means is in a state of outputting the predetermined output signal,
Alternatively, it has a display device for displaying when the temperature of the temperature sensor reaches a second temperature higher than the first temperature to stop the driving of the heating element or to reduce the heating output of the heating element. The cooker described. 3. A heating coil, a frequency conversion device for supplying a high-frequency current to the heating coil, a heating element that generates heat when a current of a commercial frequency is passed, and a heating element control means for controlling energization of the heating element. A cooling fan for cooling electric parts, a power switch for switching connection and disconnection of the frequency converter or the heating element to a commercial power source, and a motor for the cooling fan connected to a commercial power source side of the power switch, The temperature detection means detects a temperature of a portion that changes depending on the temperature of the heating element and outputs a predetermined signal on condition that the temperature exceeds at least a predetermined temperature, and detects the temperature at a predetermined time point. Storage means for storing and outputting a predetermined output signal according to the state of the output signal of the means, and at least the storage means outputs the predetermined signal A heating cooker configured to drive a motor driving means of the cooling fan when any one of a state in which the frequency conversion device is driven, a state in which the frequency conversion device is driven, and a state in which the heating element is driven occurs. 4. The heating cooker according to claim 3, further comprising a timer means, wherein a period during which a predetermined signal output from the storage means is output is set by the timer means. 5. The display device for displaying or notifying that at least the frequency conversion device and the heating element are not driven, and the storage means outputs a predetermined output signal to bring the cooling fan into an operating state. Cooking device. 6. A timer means for starting the integration of time in relation to the timing at which the heating element is stopped and a memory for storing the output state of the temperature detection means in relation to the timing at which the heating element is stopped. Means for driving the motor drive means based on the stored content of the storage means, and when the timer means outputs a time-up signal after a lapse of a predetermined time after starting integration of time, the stored content of the storage means The cooking device according to claim 4, wherein the driving of the motor drive means based on the above is prohibited. 7. A timer means for starting the integration of time in relation to the timing at which the heating element is stopped and an output of the temperature detection means in relation to the timing at which both the heating element and the frequency conversion device are stopped. When the motor driving means is driven based on the stored contents of the storing means, and the timer means starts the integration of time, and outputs a time-up signal after a predetermined time has passed,
The heating cooker according to claim 4, wherein the driving of the motor drive means based on the stored contents of the storage means is prohibited. 8. A timer means for starting the integration of time in relation to the timing when the heating element and the frequency conversion device are both stopped, and an output of the temperature detection means in relation to the timing when the heating element is stopped. When the motor driving means is driven based on the stored contents of the storing means, and the timer means starts the integration of time, and outputs a time-up signal after a predetermined time has passed,
The heating cooker according to claim 4, wherein the driving of the motor drive means based on the stored contents of the storage means is prohibited. 9. A timer means for starting the integration of time in relation to the timing when the heating element and the frequency conversion device are both stopped, and a timing when the heating element and the frequency conversion device are both stopped. Storage means for storing the output state of the temperature detecting means, the motor driving means is driven based on the stored contents of the storing means, and after the timer means starts the integration of time, the time elapses after a predetermined time elapses. The heating cooker according to claim 4, wherein when the signal is output, the driving of the motor drive means based on the stored contents of the storage means is prohibited.