JP2924632B2 - Cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooking device provided with a heating means using a resistance heating element and an induction heating means.

[0002]

2. Description of the Related Art In recent years, a heating cooker has been developed in which a heating coil for generating a high-frequency magnetic field and inductively heating a load pan and a resistance heating element for generating a current by supplying a commercial frequency current are provided in the same housing.

[0003] A conventional heating cooker will be described below. FIG. 6 shows a conventional built-in heating cooker equipped with two heating burners for induction heating, one heating burner using a normal resistance heating element, and a heating chamber equipped with a resistance heating element. . In FIG. 6, the main body is divided into an upper unit 1 and a lower unit 2. Upper unit 1
Is covered with an upper case 3 made of an iron plate and a top plate 4 made of a ceramic, in which a heating coil 5a and a heating coil 5b for induction heating and a nichrome heater for resistance heating for heating by supplying a commercial frequency current. 7 is arranged below the top plate 4 so as to face the top plate 4. The cooling fan 8 is provided on the near side of the bottom surface of the upper case 3 together with the intake port provided near the lower part thereof, and a plurality of exhaust ports 9 are provided on the rear upper surface of the upper case 3. An opening 25 is provided on the rear bottom surface of the upper case 3.

The lower unit 2 is covered with a lower case 6 made of an iron plate. A cooling fan 10 is provided inside the lower case 6 in proximity to the intake port 11, and a transistor which is a component of an inverter for supplying a high-frequency current to the heating coil 5b. Cooling fins 12 with a control board 13 on which control components are mounted
And a main board 14 on which high-current components such as a resonance capacitor and a rectifier are mainly mounted.
6 are provided.

Similarly, a cooling fin 15, which is a component of an inverter for supplying a high-frequency current to the heating coil 5a,
The control board 16 and a main board (not shown) are provided between the cooling fan 10 and the exhaust port 26. Power supply board 1
Reference numeral 7 denotes a printed wiring board on which a filter coil and a drive circuit of the cooling fan 10 are mounted.

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

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

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

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

[0010]

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

The present invention solves the above-mentioned conventional problems. A frequency conversion device such as a heating coil, a nichrome heater and an inverter, and a filter unit such as a drive unit and a filter of the nichrome heater are concentrated in an upper unit, and the lower unit is concentrated on the lower unit. In order to simplify the installation work by reducing the weight of the unit and reducing the number of upper and lower connection lines, in this case, the high frequency generated from the frequency converter leaks to the low frequency part, and the nichrome heater or heating A first object is to prevent an electronic component constituting a circuit such as a frequency conversion device from overheating due to a rise in the temperature of a storage.

A second object of the present invention is to prevent the electronic components from rising due to the residual heat of the nichrome heater or the heating chamber after the power switch is turned off, thereby preventing malfunction and destruction.

A third object of the present invention is to prevent the electronic component from rising in temperature due to the residual heat of the nichrome heater or the heating chamber to prevent malfunction and destruction by driving the cooling fan even after the power switch is turned off. Then, the cooling fan is operated for a long period of time to prevent the user from feeling uneasy or to prevent the fan noise from being generated for a long period of time.

A fourth object of the present invention is to prevent the temperature of the electronic components inside the apparatus from excessively rising due to the heat of the heating element regardless of the operation of the frequency converter or the heating element or the operation of the power switch. Is to prevent

[0015]

Means for Solving the Problems A first means of the present invention for achieving the first object includes a heating coil,
A first printed wiring board for mounting and electrically connecting components of a frequency conversion device that supplies a high-frequency current to the heating coil, filtering means for filtering high-frequency noise generated by the frequency conversion device, A heating element that generates heat by passing an electric current, a heating element control unit that controls energization of the heating element, and a conductive metal material that is disposed to face the lower side of the heating element and reflects heat radiated by the heating element. Shielding means, a cooling fan for cooling electric components, and a motor driving means for driving a motor of the cooling fan. The heating element control means, the filtering means, and the motor drive are provided below or near the shielding means. There is provided a heating cooker provided with a second printed wiring board on which the means is placed and electrically connected.

The second means of the present invention for achieving the second object is a heating coil, a frequency converter for supplying a high-frequency current to the heating coil, and a heater for supplying heat at a commercial frequency. A heating element, a heating element control means for controlling energization of the heating element, a power switch for switching connection to and disconnection from commercial power, a control power generation means connected to the commercial power side of the power switch, A cooling fan motor connected to the commercial power supply side of the power switch or a motor driving means for driving the cooling fan motor; and detecting a temperature of a portion which changes depending on a temperature of the heating element and detecting the temperature at least a predetermined value. A temperature detection means for outputting a predetermined output signal on condition that the temperature exceeds a predetermined temperature, and a control power supply voltage of the temperature detection means is supplied from the control power generation means. When at least one of a state in which the temperature detection unit outputs the predetermined output signal, a state in which the frequency conversion device is driven, and a state in which the heating element is driven occurs, the motor A heating cooker configured to drive a driving unit is provided.

In order to achieve the third object, a third means according to the present invention, in addition to the second means, further comprises a timing or frequency converter for stopping the power supply to the heating element control means and the heating element. Timer means for starting the accumulation of time in relation to the timing at which the energization of both is stopped, and when the timer means outputs a time-up signal after a lapse of a predetermined time after the start of the accumulation of time, the temperature detection means A heating cooker configured to prohibit driving of a motor driving unit by an output signal is provided.

According to a fourth aspect of the present invention, there is provided an induction heating cooker according to the present invention, wherein, in addition to the second means or the third means, a heating element control means in response to an output signal of a temperature detection means. Provided is a heating cooker configured to prohibit energization or reduce output.

[0019]

According to the first means, the first component for mounting and electrically connecting the components of the frequency converter for generating the high-frequency magnetic field is provided.
And the second printed wiring board for mounting and electrically connecting the heating element control means for controlling the heating element using a low frequency power supply, the filtering component and the motor driving means. Electromagnetic coupling between both printed wiring boards is reduced. Further, the shielding means provided opposite to the heating element and provided to reflect the heat radiated by the heating element is made of a conductive metal material, and has a function other than the function of shielding the radiant heat from the heating element. In addition, since the conductive metal material has a function of blocking the high-frequency magnetic field, the high-frequency magnetic field generated from the first printed wiring board is provided on the second printed wiring board provided below and below the blocking means. Suppress linkage. An operation of separating the first printed wiring board serving as the high-frequency generation source and the second printed wiring board of the low-frequency potential portion to separate the coupling of the high-frequency magnetic field to reduce the high-frequency coupling;
Due to the magnetic field blocking effect of the blocking means below the heating element, it is possible to suppress a high frequency current from being induced to the low frequency potential of the second printed wiring board and leaking to the commercial power supply. Also, the second
When the cooling fan is stopped immediately after the power is turned off, the printed wiring board may exceed the heat resistant temperature due to the overshoot of the heat due to the influence of the heat of the heating element and the heat of the heating element such as a heating chamber disposed at the lower part of the housing. However, since the second printed wiring board is provided with motor driving means for driving the motor of the cooling fan and heating element control means, these components can be connected by pattern wiring on the same printed wiring board. This makes it easy to install a device that detects the temperature effect of the heating element and drives the cooling fan motor or controls the output of the heating element according to the detection result, for example, cooling even if the power switch is turned off. Control such as driving the fan for a predetermined time can be realized on the second printed wiring board at low cost and in a small space.

According to the second means, the motor of the cooling fan or the motor driving means for driving the motor of the cooling fan is connected to the commercial power supply side of the power switch. The control power supply voltage of the temperature detection means for detecting the temperature and outputting a predetermined output signal on condition that the temperature exceeds at least the predetermined temperature is supplied from the control power generation means connected to the commercial power supply side of the power switch. When the output signal of the temperature detecting means outputs the predetermined output signal, the motor driving means of the cooling fan is driven, so that the power switch is turned off or both the operation of the frequency conversion device and the operation of the heating element control means are stopped. However, immediately after that, when the temperature of the place detected by the temperature detecting means rises, the motor of the cooling fan can be operated, and the power switch can be operated. After Ji off, or immediately after the frequency converter or heating element are both stopped, the temperature of the electronic components in the residual heat, such as heating element can be prevented from increasing. Further, when at least one of a state in which the output signal of the temperature detecting means outputs the predetermined output signal, a state in which the frequency converter is driven, and a state in which the heating element is driven occurs, the motor drive is performed. Since the cooling fan is operated by driving the means, the temperature of the place detected by the temperature detecting means is low and the frequency conversion is performed regardless of whether the power switch is on or off or whether the frequency converter and the heating element are driven or not. Since the motor of the cooling fan is driven except when the operation of both the device and the heating element is stopped, it is possible to stably suppress the temperature rise of the internal electronic components.

By the third means, when the heating element is energized and the temperature detected by the temperature detecting means rises, and the output signal of the temperature detecting means outputs the predetermined output signal, the power supply is turned off or the frequency is changed. Even after both the converter and the heating element are stopped, the motor driving means is driven and the cooling fan operates, but the timer means sets the time in relation to the timing at which the energization of the heating element control means or the frequency converter is stopped. When the integration is started and a time-up signal is output after a predetermined time has elapsed, the driving of the motor driving means by the temperature detecting means is prohibited. There is no fear that the cooling fan will continue to operate for hours.

According to the fourth means, only the energization of the heating element having the greatest effect on the internal temperature is inhibited or the output is reduced in accordance with the output signal of the temperature detecting means.
Even if the cooling fan motor is driven when the temperature of the heating element is rising, the temperature of the electronic component can be effectively prevented from becoming higher than the heat-resistant temperature when the intake / exhaust port is closed, etc. be able to. In addition, since energization of the frequency conversion device is not prohibited, the inconvenience that the user cannot cook at all can be eliminated.

[0023]

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

A printed wiring board is provided on the back surfaces of the operation unit 34 and the display unit 35, and a signal line 42a connected by a connector on the wiring board is connected by a connector 40 to a signal line 42b coming out of the upper unit 26. You. The connection line 43 is connected to the power switch 33 and is connected to a connection line 44 extending from the upper unit 26 by a connector 41.

An engaging portion 45 and an engaging portion 46 are provided on both sides of a bottom surface of the upper unit case 28, and an upper portion of the side plate of the lower unit case 32 is woven and bent inward to form an engaging portion 47 and an engaging portion 48. Is provided.

FIG. 2 shows a plan layout of internal components of the upper unit case 26. Inverter board 50 as main component
, An inverter board 51, a power supply board 52, a cooling fan 53, and a cooling fan 54 are arranged on the bottom surface of the upper unit case with an appropriate insulation distance set as shown in the figure. A heating coil 55 shown by a broken line is provided on the upper part of the inverter board 50, a heating coil 56 shown by a broken line is provided on the upper part of the inverter board 51, and a nichrome heater 57 shown by a broken line is provided on the upper part of the power supply board 52. And
FIG. 3 shows a partial cross section taken along the line AA ′ in FIG. In FIG. 3, the heating coil 56 is a heating coil base 56 made of resin.
b, the nichrome heater 57 is fixed to the bottom surface of a case 57a made of an inorganic material having a heat insulating effect, and a heat insulating plate 57b formed of an aluminum plate is provided below the case 57a. A power supply board 52 on which components such as the filter coil 102 and the filter coil 105 are mounted is provided below and near the plate 57b. In FIG. 2, an intake duct 58, an intake duct 59, and an exhaust duct 60 are formed on both sides on the rear side.
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 this figure, a power supply board 52, an inverter board 50, an inverter board 51, and an operation board 62 are shown by dashed lines. The commercial power supply 63 is connected to the power supply board 52, and the filter capacitor 1
01 is connected between the lines. The power switch 33 has two contacts and turns on and off the input power of the inverter board 50 and the input power of the inverter board 51 at the same time. Power supply board 5
2, the filter coil 102 and the filter capacitors 103 and 104 connected between the power supply lines and the housing are connected between the power supplies on the inverter board 50 side as viewed from the switch 33, and the inverter board 51 side as viewed from the switch 33. Are connected to the filter coil 105 and filter capacitors 106 and 107 connected between each power supply line and the housing. Between the connection point between the power switch 33 and the input terminal of the filter coil 105 and the other pole terminal of the power supply line, a series circuit of the nichrome heater 57 and the relay 109 and a series circuit of the heating chamber heater 64 and the relay 110 are connected in parallel via the triac 108. The circuit is connected.

A series circuit of a parallel circuit of the fan motor 65 and the fan motor 66 and a triac terminal of the photo triac coupler 111 are connected between the input terminals of the power switch 33. The primary winding of the transformer 113 is connected between the input terminals of the power switch 33. The secondary winding of the transformer 113 is connected to a DC power supply circuit 114, and the DC power supply circuit 114 supplies a DC voltage to a relay drive circuit 115, a relay drive circuit 116, and a fan motor drive circuit 117. The fan motor drive circuit 117 inputs the signals of the phototransistor 118, the phototransistor 119, and the temperature detection circuit 122, and drives the phototriac coupler 111. As shown in FIG. 2, the temperature detection circuit 122 outputs a signal to the fan motor drive circuit 117 in response to a signal from the thermistor 121 fixed near the triac 108 on the power supply board 52.

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. Have been. An inverter circuit 204 that supplies a high-frequency current to the heating coil 55 is connected to an output terminal of the rectifier 203. The control circuit 205 is a circuit that drives a switching element of the inverter circuit 204 to control the output. The secondary winding of the transformer 202 is connected to a DC power supply circuit 206, and the DC power supply circuit 206
2 is supplied with a DC power supply. The control circuit 205 also controls the phototransistor 119
Output the driving signal.

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

The operation of the heating cooker constructed as described above will now be described. In FIG. 1, when the apparatus is installed on a sink or the like, first, the upper unit 26 is dropped into a rectangular hole formed in a top plate of the sink or the like. The upper unit 26 is supported on a top plate surface by a top frame 30. In this state, the lower unit 27 is inserted from the front of the hole provided on the front surface of the sink or the like into the engaging portions 45, 4 of the upper unit 26.
The lower unit can be fixed so that the lower unit 27 can be suspended from the upper unit 26 by inserting the engaging units 47 and 48 of the lower unit 27 into engagement with the engaging units 47. The connector 40 and the connector 41 can be connected in the middle of the insertion of the lower unit.

When the power switch 33 is turned on and the input key of the operation unit 34 is pressed, the upper unit 26 shown in FIG.
A fan motor drive circuit provided on the power supply board 52 simultaneously drives the cooling fan 53 and the cooling fan 54, and each cooling fan passes through a plurality of holes provided in the intake duct 58 and a plurality of partition plates 61 on the front surface of the intake duct 59 to be connected to the outdoor. Inhale each air. The air blown from the outlets of the cooling fans 53 and 54 is supplied to the inverter board 50 and the inverter board 5.
After the heat-generating components and electronic components on each inverter board 50 are cooled by the guides provided on the respective components 1, the heat-generating components and electronic components are folded back at the center to cool the electronic components on the power supply board 52 and provided on the wall in front of the exhaust duct 60. The air is exhausted from the plurality of holes through the exhaust duct to the upper outdoor.

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

On the other hand, the shielding plate 57b of the nichrome heater 57
Since components having a commercial power supply potential, such as the filter coil 102 and the filter coil 105, are mounted on the power supply board 52 in the lower part, the intensity of the magnetic field generated by the heating coil 55 and the heating coil 56 decreases as described above, It is possible to suppress high frequency noise from being superimposed on the commercial power supply potential and leaking to the commercial power supply side of the device.

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

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

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

When the control circuit 205 receives a drive signal of the inverter circuit 204 from the input circuit 301, it sends a drive signal to the fan motor drive circuit 117 via the phototransistor 119, and the control circuit 215 controls the inverter 214 or the nichrome heater 57 or the heating chamber. When a drive signal for the heater 64 is received, a drive signal is sent to the fan motor drive circuit 117 via the phototransistor 118. When any of these drive signals is input, the fan motor drive circuit 117 drives the phototriac coupler 111. Thus, the fan motor 65 and the fan motor 66 built in the cooling fans 53 and 54 operate.

Since the thermistor 121 is mounted on the power supply board 52, when the atmosphere rises, the temperature detection circuit 1
22 outputs a drive signal to the fan motor drive circuit 117. Therefore, even if the power switch 33 is turned off, the fan motor 65 and the fan motor 66 are driven, and the nichrome heater 57, the heating chamber heater 64, or the heating chamber 49 ( It is possible to prevent the electronic component from being overheated and destroyed due to the temperature overshoot due to the residual heat in FIG. 1).

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

As described above, according to the present embodiment, the inverter board 50 and the inverter board 51 for mounting and electrically connecting the components of the inverter for generating high frequency, the nichrome heater 57 for flowing the low frequency current, and the heating chamber A relay 109 or a relay 110 for controlling the heater 64;
02, a filter component such as a filter coil 105, and a power supply board 52 on which a motor driving means such as a phototriac coupler 111 are mounted. The power supply board 52 is provided below a nichrome heater 57. Since it is disposed under the negative plate 57b, the high frequency magnetic field generated by the heating coil 55, the heating coil 56, the inverter board 50, the inverter board 51, and the like causes the low frequency potential of the power board 52 to be applied to the commercial power supply outside the device. High-frequency noise can be suppressed from leaking out.

A photo triac coupler 111 is mounted on the power supply board 52, and a series circuit of the connector connected to the parallel circuit of the windings of the fan motor 65 and the fan motor 66 and the photo triac coupler 111 is a commercial power switch 33. A temperature detecting circuit which is pattern-wired so as to be connected to the power supply 63 side, and outputs a drive signal for the fan motor 65 and the fan motor 66 when the temperature of the power supply board 52 is detected by the thermistor 121 and the temperature exceeds a predetermined temperature and becomes abnormal. 122, a control power supply voltage of the temperature detection circuit 122 is supplied by a transformer 113 and a DC power supply circuit 114 connected to the commercial power supply side of the power switch 33, and a drive signal of the temperature detection circuit 122 is output. Or
When the inverter circuit 204, the inverter circuit 214, the nichrome heater 57, or the heating chamber heater 64 is driven, the fan motor 65 and the fan motor 66 are driven. Therefore, even when the heating source is energized, the heating source is All off or power switch 3
3 is turned off, fan motor 65 and fan motor 6
6 can be operated, and after the power switch 33 is turned off, it is possible to prevent the temperature of the electronic component from rising due to residual heat of the nichrome heater 57 and the heating chamber heater 64.

In addition to the DC power supply circuit 114, the control power supply voltages of the control circuits 205 and 215 and the input circuits 301 and 302 are supplied from the transformers 202 and 212 and the DC power supply circuits 206 and 216 connected to the load side of the power switch 33. When the power switch 33 is turned off, the supply of control DC power to the control circuits 205 and 215 and the input circuits 301 and 302 can be stopped.
3. The power consumption at the time of turning off can be saved.

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

In the above-described embodiment, the fan motor 65 and the fan motor 66 are connected to the commercial power supply side of the power switch 33 in series with the phototriac coupler 111 as AC motors, 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.

In the above embodiment, the triac 108 is provided on the power supply board 52.
8 has a large calorific value and may increase the temperature. Therefore, if the triac 108 is an insulating type,
This may be removed from the power supply substrate 52 and attached to a heat radiator such as a housing.

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

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

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

In FIG. 5, the power switch 33, the nichrome heater 57, the fan motor 65, the triac 108,
The relay 109, the phototriac coupler 111, the phototransistor 118, the phototransistor 119, the phototriac coupler 120, the thermistor 121, the control circuit 205, the control circuit 215, the input circuit 302, and the phototransistor 303 are the same as those of FIG. The function is performed, and the description is omitted. Frequency converter 67
The frequency converter 68 is a circuit block constituting an induction heating cooker including a rectifier and an inverter circuit.

What differs from FIG. 4 is the configuration described below. First, a diode 417 is connected to the output of the temperature detection circuit 401.
PNP transistor 4 via a series circuit of
03 is connected to the connection point of the resistors 412 and 413 via the diode 418 at the same time. The collector of the PNP transistor 403 is a resistor 408
NPN transistor 4 via a series circuit of
Connected to 10 bases. Resistance 408 and resistance 40
A diode 407 is connected between the connection point 9 and the output terminal of the timer circuit 404. The reset circuit 405 receives the collector voltage of the NPN transistor 414 and resets the integrated time of the timer according to the level. The timer circuit 404 holds the output at HI in the reset state and until a predetermined time elapses after the reset is released.
The drive winding of the relay 109 and the NPN transistor 414 are connected in series between the DC power supply potential and the ground potential,
A resistor 412 and a resistor 4 are connected between the base of the N transistor 414 and the emitter of the phototriac coupler 303.
Thirteen series circuits are connected. The emitters of the phototriac coupler 118 and the phototriac coupler 119 are connected to each other and connected to the base of the NPN transistor 411 via the resistor 415. A parallel circuit of an NPN transistor 410 and an NPN transistor 411 and a series circuit of a diode section of the phototriac coupler 111 are connected between a DC power supply potential and a ground potential.

The operation of the heating cooker configured as described above will be described below. When the power switch 33 is turned on and at least one of the frequency converter 67, the frequency converter 68, and the nichrome heater 57 is started, a signal is output from the control circuit 205 or the control circuit 215, the NPN transistor 411 is turned on, and the phototriac coupler 111 is turned on. Are conducted, and the fan motor 65 is driven. When an input key for driving the nichrome heater 57 is pressed, the phototransistor 303 is turned on by the output signal of the input circuit 302, the NPN transistor 414 is turned on, and the contact of the relay 109 is turned on.

Frequency converter 67 and frequency converter 68
When the internal temperature rise level increases and exceeds a predetermined temperature level, the temperature detection circuit 401 sets the level of the output terminal connected to the resistor 402 to LO, so that the PNP transistor 403 is turned on. Become. Therefore, NPN transistor 410 conducts, but at this time, since NPN transistor 411 is already conducting, no change occurs in the operation of the fan motor. The temperature detection circuit 401 is a diode 41
Since the connection point between the resistor 412 and the resistor 413 is set to LO through 8, the NPN transistor 414 is turned off, the contact of the relay 109 is opened, and the power supply to the nichrome heater 57 is stopped. Therefore, the temperature rise due to the influence of the nichrome heater is eliminated, so that a thermal failure of the electronic component can be prevented.

On the other hand, in the above-mentioned state, when the internal temperature rise becomes large and the power switch 33 is turned off immediately before or almost simultaneously with the operation of the temperature detection circuit 401, the signals from the control circuits 205 and 215 disappear. Therefore, the NPN transistor 411 is turned off,
Since the NPN transistor 410 is on as described above, the fan motor 65 continues to operate. Then, when the temperature of the temperature sensor 121 falls below a predetermined level, the output signal of the temperature detection circuit 401 becomes HI.
Or when the signal of the timer circuit 404 becomes LO, N
The PN transistor 410 turns off and the operation of the fan motor 65 stops. Therefore, when the internal temperature is high,
Even if the power switch 33 is turned off, it is possible to prevent the temperature from overshooting due to the residual heat of the nichrome heater 57 and causing the internal electronic components to be thermally destroyed.

Also, the timer circuit 404 does not always start the time accumulation from the power-off time, but resets the accumulated time and outputs the output signal when the relay 109 for controlling the energization of the nichrome heater 57 is turned on by the reset circuit 405. The temperature is maintained at HI, and after the reset is released after the energization of the nichrome heater 57 is stopped, the driving of the fan motor 65 by the temperature detection circuit 401 is prohibited after a lapse of a certain period of time. The driving time of the fan motor 65 after the switch 33 is turned off or after the driving of all the heating burners is stopped can be automatically adjusted.

As described above, regardless of whether the power switch 33 is on or off, the temperature detection circuit 401 detects the internal temperature and drives the fan motor 65, and the timer circuit 404 sets the time in synchronization with the stop of the energization of the nichrome heater 57. After a predetermined time from the start of the integration, a time-up signal is output and the driving of the fan motor 65 by the temperature detection circuit 401 is prohibited.
5 does not rotate, the temperature of the electronic components does not overshoot, and there is no fear that the fan motor 65 will continue to operate for a long time.

The temperature detecting circuit 401 drives the fan motor 65 when the internal temperature becomes equal to or higher than a predetermined value.
Nichrome heater 57 that has the greatest temperature effect on internal components
Since the power supply to the device is stopped, when the intake and exhaust ports of the device are clogged with dirt, dust, etc., the temperature inside the device is quickly lowered to prevent the temperature of the electronic components from becoming higher than the heat resistant temperature and preventing breakdown. be able to. Further, since energization of the frequency conversion device 67 or the frequency conversion device 68 is not prohibited, the inconvenience that the user cannot cook at all can be eliminated.

In the second embodiment, the timer circuit 404 starts the time accumulation in synchronization with the interruption of the relay 109, that is, the stop of the energization of the nichrome heater 57. The same effect can be obtained by a configuration in which the integration of the timer 405 is started. In this case, the fan motor can be stopped if a predetermined time has always passed since the power switch was turned off or all the heat sources were turned off. Further, the timing of the time accumulation start of the timer 404 may be related to the timing of stopping the energization of the nichrome heater 57 or the timing of turning off all the heating sources, and there may be a slight time lag.

Further, in the second embodiment, the relay 1
In this configuration, the integration time of the timer 404 is reset in accordance with the turning on of the contact 09, for example, the transistor 41
The integration of time may be reset by driving the cooling fan motor 1 and the cooling fan motor may be driven, or the integration time may be reset under the condition that any heating source is driven.

[0061]

As described above, the first means of the present invention is arranged so as to oppose the first printed wiring board on which the components of the frequency converter are mounted and electrically connected to each other, below the heating element. A second printed wiring board for mounting and electrically connecting the heating element control means, the filtering means, and the motor driving means is provided below or near the shielding means made of a conductive metal material. It is possible to reduce the size by mounting at a high density, suppress leakage noise to the outside, and prevent thermal destruction of internal electronic components.

Further, the second means of the present invention supplies the control power supply voltage of the temperature detecting means from the control power supply means connected to the commercial power supply side of the power switch, and supplies at least the heating element measured by the temperature detecting means. The motor driving means when any one of a state in which the temperature of a portion that changes depending on the temperature exceeds a predetermined temperature, a state in which the frequency converter is driven, and a state in which the heating element is driven occurs. So that the cooling fan motor can be operated even if the power switch is turned off or the frequency converter and the heating element control means are both stopped. It is possible to prevent the temperature of the electronic component from rising due to the residual heat.

A third means of the present invention is a timer means for starting integration of time in relation to the timing at which the heating element control means is de-energized or the timing at which both the frequency converter and the heating element are de-energized. When the timer means outputs a time-up signal after a lapse of a predetermined time after the start of time accumulation, the driving of the motor driving means by the output signal of the temperature detecting means is prohibited. After both the device and the heating element control means are stopped, the cooling fan is stopped to prevent the temperature of the electronic component from rising due to the residual heat of the heating element and the like. The cooling fan continues to operate for a long time after both the heating element control unit and the heating element control unit have stopped, eliminating the risk of giving the user anxiety. Kill.

Further, the fourth means of the present invention has a structure in which the energization of the heating element control means is inhibited or the output is reduced in accordance with the output signal of the temperature detection means. In addition, it is possible to prevent the electronic component from being broken when the temperature becomes higher than the heat resistant temperature. In addition, since energization of the frequency conversion device is not prohibited, it is possible to eliminate the disadvantage that the user cannot cook at all.

[Brief description of the drawings]

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

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

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

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

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

FIG. 6 is a perspective view of a conventional heating cooker.

[Explanation of symbols]

33 Power switch 50, 51 Inverter board (first printed wiring board) 52 Power board (second printed wiring board) 53, 54 Cooling fan 55, 56 Heating coil 57 Nichrome heater (heating element) 57b Heat shield 64 Heating Storage heater (heating element) 65, 66 Fan motor 67, 68 Frequency converter 102, 105 Filter coil (filtering means) 103, 104, 106, 107 Filter capacitor (filtering means) 109, 110 Relay (heating element control means) 111 Phototriac coupler (motor driving means) 113 Transformer (control power generating means) 114 DC power supply circuit (control power generating means) 121 Thermistor (temperature detecting means) 122 Temperature detecting circuit (temperature detecting means) 204, 214 Inverter circuit (frequency conversion) Device) 205, 215 Control Road (frequency converter) 401 temperature sensing circuit (temperature detection means) 404 timer circuit (timer means)

Continuation of the front page (56) References JP-A-7-272847 (JP, A) JP-A-3-286924 (JP, A) JP-A-3-213908 (JP, A) JP-A-3-191215 (JP) JP-A-3-1483 (JP, A) JP-A-2-295092 (JP, A) JP-A-2-150700 (JP, U) JP-A-3-48894 (JP, U) JP-A-3-48894 3-71597 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05B 11/00 H05B 6/12 335

Claims (4)

(57) [Claims] 1. A heating coil, a first printed wiring board for mounting and electrically connecting a component of a frequency converter for supplying a high-frequency current to the heating coil, and a high-frequency noise generated by the frequency converter. Filtering means for filtering, a heating element for generating heat by passing a commercial frequency current, a heating element control means for controlling energization of the heating element, and radiation of the heating element disposed below and opposed to the heating element Shielding means made of a conductive metal material that reflects heat to be heated, a cooling fan for cooling electric components, and a motor driving means for driving a motor of the cooling fan, wherein the heating element control is provided below or near the shielding means. A heating cooker comprising a second printed wiring board on which the means, the filtering means, and the motor driving means are mounted and electrically connected. 2. A heating coil, a frequency conversion device for supplying a high-frequency current to the heating coil, a heating element that generates heat by flowing a commercial frequency current, and a heating element control unit that controls energization of the heating element. A power switch for switching connection to and disconnection from a commercial power supply, control power generation means connected to the commercial power supply of the power switch, and a cooling fan motor or the cooling fan connected to the commercial power supply of the power switch Motor driving means for driving the motor, and temperature detecting means for detecting a 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 a predetermined temperature. Wherein the control power supply voltage of the temperature detecting means is supplied from the control power generating means, and at least the temperature detecting means outputs the predetermined output signal. The heating cooker is configured to drive the motor driving means when any one of a state in which the frequency converter is driven, and a state in which the heating element is driven occurs. 3. A timer means for starting integration of time in relation to a timing at which the heating element control means is de-energized or a timing at which both the frequency converter and the heating element are de-energized, the timer means comprising: 3. The heating cooker according to claim 2, wherein when a predetermined time elapses after the start of time accumulation and a time-up signal is output, the driving of the motor driving means by the output signal of the temperature detecting means is prohibited. 4. The heating cooker according to claim 2, wherein the power supply to the heating element control means is inhibited or the output is reduced in accordance with an output signal of the temperature detection means.