JP2015017788A - Heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To early detect a rotation abnormality of a circulation fan in a heating cooker that cooks an object to be cooked by circulating hot air generated by an oven burner in a heating chamber.SOLUTION: A heating cooker comprises a circulation fan and a motor 4 for rotating the circulation fan, and is provided with a drive control unit 105 for driving the motor 4, a drive characteristic detection unit 106 for detecting a drive characteristic of the motor 4, a storage unit M for storing a threshold value of the drive characteristic of the motor 4 for determining a rotational state of the circulation fan; and a fan state determination unit 107 for determining the rotational state of the circulation fan by comparing the drive characteristic detected by the drive characteristic detection unit 106 with the threshold value of the drive characteristic.

Description

  The present invention relates to a cooking device for cooking food to be cooked by circulating hot air generated by burning an oven burner to a heating chamber using a circulation fan. In particular, the present invention relates to a cooking device that can detect rotation abnormality of a circulation fan.

  2. Description of the Related Art Conventionally, in order to bake fish or the like, there is known a heating cooker that performs grill cooking by arranging a direct heating means such as a gas combustion type grill burner or an electric heater in a heating chamber that accommodates an object to be cooked. According to the cooking device having the direct heating means, the food to be cooked can be cooked at a high temperature, so that the food to be cooked can be burnt firmly and excellent in appearance when finished. Depending on the type and size, uneven baking is likely to occur, and protrusions such as a burner are disposed in the heating chamber, so that cleaning during cleaning is difficult.

  From the above viewpoint, the present application is a heating cooker in which an oven burner that generates hot air is provided separately from the heating chamber, and the generated hot air is sent to the heating chamber by a circulation fan and circulated to perform oven cooking A person previously proposed (Patent Document 1). According to this heating cooker, compared to a case where a direct heating means such as a grill burner is provided in the heating chamber, uneven baking is less likely to occur in the cooking object, and it is possible to bake evenly into the cooking object. Further, by circulating hot air, heat can be quickly distributed throughout the heating chamber, so that cooking in a short time becomes possible. Furthermore, since no protrusion such as a grill burner is provided in the heating chamber, the heating chamber can be easily maintained.

  By the way, when to-be-cooked things, such as a fish and meat, are baked with the above-mentioned heating cooker, the salt content from the to-be-cooked object, fats and oils, etc. are contained in the hot air circulated to a heating chamber. Therefore, salt or the like contained in the hot air is attached to components such as a blade for the circulation fan or a bearing for fixing the circulation fan to the rotating shaft of the motor due to the circulation of the hot air. As a result, if corrosion of these components progresses over a long period of use, the connection between the circulation fan and the rotating shaft of the motor becomes insufficient, and rotation abnormality such as the circulation fan spinning may occur.

  In order to determine abnormal rotation of the circulation fan that circulates hot air, an oven temperature detection element that detects the temperature in the vicinity of the circulation fan and an indoor temperature detection element that detects the temperature in the heating chamber are provided, and the indoor temperature detection element outputs A heating cooker has also been proposed that outputs an abnormal signal when the temperature difference between the temperature signal and the temperature signal output from the oven temperature detection element is larger than a threshold value (Patent Document 2).

  However, an oven burner is provided in a combustion chamber different from the heating chamber, and in a heating cooker that circulates the hot air generated in the combustion chamber by the circulation fan and circulates it, rotation abnormality such as idling of the circulation fan occurs. Then, since the air volume decreases, a certain time is required until the hot air generated in the combustion chamber is sent to the vicinity of the circulation fan. Further, a temperature detection element such as a thermistor is inferior in quick response. Therefore, if the oven burner is burned for a certain period of time and the temperature in the vicinity of the circulation fan does not rise to some extent, there is a problem that the rotation abnormality of the circulation fan cannot be accurately determined. As a result, if there is a delay in the determination of the circulation fan rotation abnormality and the connection between the circulation fan and the rotating shaft of the motor is inadequate, not only noise will be generated, but the combustion performance of the oven burner will be reduced, May cause local overheating.

JP 2013-68406 A JP-A-6-221565

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a circulation fan in a cooking device for cooking an object to be cooked by sending hot air generated by an oven burner into a heating chamber and circulating it. It is to determine the rotation abnormality of the earliest.

The present invention comprises an oven burner that generates hot air by burning gas,
A heating chamber for heating the cooking object;
A circulation fan for sending and circulating hot air generated by the oven burner to the heating chamber;
A motor that rotationally drives the circulation fan;
A heating cooker having a control device capable of determining rotation abnormality of the circulation fan,
The controller is
A drive control unit for controlling the drive of the motor;
A drive characteristic detector for detecting the drive characteristic of the motor;
A storage unit that stores a threshold value of a driving characteristic of the motor for determining a rotation state of the circulation fan;
The cooking device includes a fan state determination unit that determines a rotation state of the circulation fan by comparing a drive characteristic detected by the drive characteristic detection unit with a threshold value of the drive characteristic.

  When the circulation fan is idling, etc., the motor load is different compared to when the circulation fan is normally driven to rotate, so a threshold for drive characteristics such as motor power that may cause rotation abnormality is set. Then, by comparing the drive characteristics of the motor that rotationally drives the circulation fan and the threshold value of the drive characteristics, the rotation abnormality of the circulation fan can be determined at an early stage.

In the heating cooker, preferably,
A temperature detection unit for detecting a temperature in the vicinity of the motor;
The storage unit stores a threshold value of the driving characteristic of the motor associated with the temperature in the vicinity of the motor.

  In a heating cooker that generates hot air using an oven burner, it is necessary to circulate high-temperature hot air, so the temperature in the vicinity of the motor installed in the appliance tends to be high. Therefore, during cooking, if the temperature in the vicinity of the motor rises higher than at the start of cooking, the drive characteristics of the motor may fluctuate even if the circulation fan is normally driven to rotate at the same rotational speed. However, according to the cooking device, since the threshold value of the driving characteristic associated with the temperature near the motor is used, it is possible to reliably determine the rotation abnormality of the circulation fan even during high temperature cooking.

In the heating cooker, preferably,
A rotation number detection unit for detecting the rotation number of the circulation fan;
The drive control unit drives the motor so that the rotational speed of the circulation fan detected by the rotational speed detection unit is maintained at a predetermined rotational speed.

  According to the above cooking device, the motor drive is controlled so that the circulation fan is driven to rotate at a predetermined number of revolutions. Therefore, if the rotation abnormality does not occur in the circulation fan, the fluctuation of the motor drive characteristics is small. Therefore, it is possible to easily set the threshold value of the drive characteristic for determining the rotation abnormality and to reliably determine the rotation abnormality.

In the heating cooker in which the circulation fan is rotationally driven at a constant rotational speed, preferably,
In the storage unit, a threshold value of the fluctuation range of the drive characteristics of the motor within a predetermined time is stored,
The fan state determination unit determines a rotation state of the circulation fan by comparing a fluctuation range of the drive characteristic within a predetermined time of the motor with a threshold value of the fluctuation range.

  If there is a partial deficiency in the connection between the circulation fan and the rotating shaft of the motor, rotation abnormality such as temporary idling of the circulation fan may occur. When the motor drive is controlled so that the circulation fan is driven to rotate at a predetermined rotation speed, when the rotation abnormality occurs in the circulation fan, the motor drive is corrected so as to recover the predetermined rotation speed. Drive characteristics such as motor power fluctuate greatly within a short time. Therefore, by setting a threshold value for the fluctuation range of the drive characteristic that may cause rotation abnormality, and comparing the fluctuation range of the drive characteristic of the motor within a predetermined time with the threshold value of the fluctuation range, Rotational abnormality can be detected early.

In the heating cooker, preferably,
The drive characteristic detection unit detects at least one drive characteristic selected from the group consisting of motor power, motor current, and motor voltage.

  When the circulation fan rotates abnormally, the load on the motor that drives the circulation fan to rotate fluctuates. Therefore, when rotating the circulation fan, the rotation abnormality of the circulation fan can be detected in a short time by detecting at least one selected from the group consisting of motor power, motor current, and motor voltage for driving the motor. can do.

In the heating cooker,
The fan state determination unit determines idling and / or sticking of the circulation fan.

  When the circulation fan is idling, the motor load is lower than when the circulation fan is rotating normally, and when the circulation fan is stuck, the circulation fan is rotating normally The load on the motor increases compared to the case. Therefore, the type of rotation abnormality can also be determined by detecting the drive characteristics of the motor.

The heating cooker is preferably
The control device further includes an operation prohibition unit that sets the appliance in an interlock state in order to prohibit cooking after the next time when the rotation abnormality is detected a predetermined number of times in the fan state determination unit.

  According to the heating cooker, when the rotation abnormality is detected a predetermined number of times, cooking after the next time becomes impossible, so that cooking in a state where the circulation fan is not sufficiently driven to rotate can be prevented.

  As described above, according to the present invention, in a heating cooker that sends and circulates hot air generated in an oven burner by a circulation fan to the heating chamber, the circulation fan is caused by salt contained in the hot air to be circulated. Rotational abnormality can be detected early. Thereby, generation | occurrence | production of a noise, the combustion failure of the oven burner resulting from the fall of an air volume, and also the local overheating of an instrument can be prevented at an early stage.

It is a schematic cross-sectional perspective view which shows an example of the heating cooker which concerns on embodiment of this invention. It is a cross-sectional principal part perspective view which shows the back part of the heating cooker which concerns on embodiment of this invention. It is a block diagram in the heating cooker which concerns on embodiment of this invention. It is a correlation diagram which shows an example of transition of the drive characteristic of a motor with the heating cooker which concerns on embodiment of this invention. It is a correlation diagram which shows another example of transition of the drive characteristic of a motor with the heating cooker which concerns on embodiment of this invention. It is a flowchart which shows a part of control operation when performing oven cooking with the heating cooker which concerns on embodiment of this invention. It is a flowchart which shows a part of control operation when performing oven cooking with the heating cooker which concerns on embodiment of this invention.

  FIG. 1 is a schematic cross-sectional perspective view of a heating cooker according to the present embodiment. This cooking device is a built-in gas stove in which a stove body 11 is incorporated in a state of being dropped into an opening of a countertop 10 of a system kitchen. In the stove main body 11, a heating chamber 3a (oven box) for accommodating the food to be cooked and a combustion chamber 3b are disposed below the heating chamber 3a. In this specification, the direction in which the door 32 side and the back side of the heating chamber 3a face each other is referred to as the front-rear direction, the width direction of the heating chamber 3a is referred to as the left-right direction, and the height direction of the heating chamber 3a is referred to as the up-down direction.

  The heating chamber 3a is configured so that an object to be cooked can be taken in and out of the heating chamber 3a by opening and closing the door 32 of the front panel. Specifically, when the door 32 is rotated forward, the plate 13 can be pulled out, and after placing an object to be cooked such as fish on the pulled out plate 13, the door 32. To be cooked is accommodated in the heating chamber 3a. Although not shown, a fire extinguisher switch for cooking the oven and an operation unit that opens forward by pressing the front panel are provided on the right side of the door 32 toward the front panel. The unit is provided with a cooking menu switch for selecting fish dishes or fried food dishes, a cooking start switch for starting oven cooking, and the like.

  The heating chamber 3a has an upper wall 33 that constitutes a ceiling portion, a lower wall 34 that is disposed to face the upper wall 33, left and right side walls 35, and a rear wall 36 at the rear (back side). The door 32 is closed so as to be openable forward. In addition, a large number of exhaust outlets 33 a communicating with the exhaust port 50 through the exhaust passage 5 formed above the upper wall 33 are formed in the rear central portion of the upper wall 33 of the heating chamber 3 a.

  As shown in FIGS. 1 and 2, the rear wall 36 of the heating chamber 3a is formed with a large number of suction ports 31 for taking in the hot air in the heating chamber 3a at the center, and a large number of suction ports 31 are provided on the left and right sides thereof. Are formed. Further, a heat shield plate 38 (see FIG. 2) is attached to the rear surface of the rear wall 36 except the region where the suction port 31 between the left and right outlets 21 and 21 is formed. Has been. A hot air passage 44 for supplying hot air of the combustion exhaust gas generated in the combustion chamber 3b to the heating chamber 3a is formed behind the heat shield plate 38.

  The combustion chamber 3b is erected upward from the rear plate of the upper plate constituting the ceiling wall of the combustion chamber 3b, the bottom plate opposed to the lower side of the upper plate, the left and right side plates, and the bottom plate. And a hot air passage forming member 45 having a rear wall facing surface 45b (see FIG. 2) disposed opposite to the heat shield plate 38 attached to the rear surface of the combustion chamber 3b. A burner 43 is provided. Although not shown, an ignition electrode and a thermocouple are provided in the vicinity of the flame hole of the oven burner 43, and a gas supply pipe for supplying gas to the oven burner 43 is adjusted and cut off. For this purpose, an original gas solenoid valve, a safety valve, and a flow rate adjustment valve are provided. Further, the cooking device has an air intake port communicating with the outside on the lower front surface or the like of the stove body 11 so that when the circulation fan 6 is driven to rotate, air is taken into the combustion chamber 3b from the outside. It is configured. Therefore, the external air taken in as combustion air and the gas are mixed and burned by the oven burner 43, whereby hot air of combustion exhaust gas is generated in the combustion chamber 3b.

  Further behind the position where the oven burner 43 is disposed, the hot air passage 44 communicates with the hot air passage 44 surrounded by the heat shield plate 38 and the hot air passage forming member 45, and hot air generated in the combustion chamber 3 b enters the hot air passage 44. It is sent.

  The hot air passage forming member 45 is in close contact with the heat shield plate 38 in such a manner as to surround the upper and left sides of the suction port 31 from the rear wall facing surface 45b located behind the heat shield plate 38, and the lower part thereof is in the combustion chamber 3b. It is open. Furthermore, an opening 45 a for sucking hot air through the hot air passage 44 by the circulation fan 6 is formed at a position facing the suction port 31 of the rear wall facing surface 45 b.

  As shown in FIGS. 1 and 2, a circulation fan case 60 is disposed further rearward of the rear wall facing surface 45b of the hot air passage forming member 45 so as to surround the hot air passage 44 formed behind the heating chamber 3a. It is installed. The circulation fan case 60 is closed at the rear surface except for the insertion portion through which the rotation shaft of the motor 4 is inserted, and the front end portion of the upper surface, the bottom surface, and both side surfaces are joined to the peripheral edge of the rear wall 36 and closed. Has been. As a result, a circulation passage 61 is formed which communicates with the hot air passage 44 through the opening 45a and communicates with the outlets 21 attached to the left and right sides of the rear wall 36 of the heating chamber 3a. A circulation fan 6 for forcibly circulating hot air in the heating chamber 3a is disposed in the circulation passage 61.

  The circulation fan 6 of the present embodiment is a suction-type circulation fan that is disposed downstream of the oven burner 43 in the hot air flow path. This circulation fan 6 is fixed to the tip of the rotating shaft of the motor 4 located at the rear, and corresponds to the formation area of the suction port 31 at the center of the rear wall 36 and the opening 45a of the rear wall facing surface 45b. Is installed. Therefore, when the motor 4 is energized to rotate the circulation fan 6, hot air in the heating chamber 3 a is sucked into the circulation passage 61 through the suction port 31 formed in the rear wall 36 and the lower combustion chamber. The hot air generated in 3b passes through the hot air passage 44 and is sucked into the circulation passage 61 from the opening 45a. And the sucked hot air is sent out into the heating chamber 3a from the outlets 21 and 21 located on both the left and right sides of the rear wall 36. As a result, hot air is forcibly circulated in the heating chamber 3a, the temperature in the heating chamber 3a is rapidly increased, and the temperature can be made uniform efficiently. Fish or meat contained in the heating chamber 3a Etc. can be cooked in an oven.

  A motor chamber 40 in which the DC motor 4 is accommodated is provided behind the circulation fan case 60 that constitutes the circulation passage 61. As shown in FIG. A supply cylinder 42 that opens downward is connected, and external air for cooling can be taken in via the supply cylinder 42. The motor 4 is driven and controlled by a power source supplied from the control device C. Although not shown, the motor 4 is provided with a rotation sensor (rotation number detection unit) composed of a Hall IC that detects the motor rotation speed, that is, the rotation speed of the circulation fan 6, and is detected by the rotation sensor. The signal is output to the control device C. Further, the motor chamber 40 is provided with a motor chamber temperature sensor (temperature detector) 48 that detects the temperature in the vicinity of the motor 4, and the detection signal detected by the motor chamber temperature sensor 48 is sent to the control device C. Is output.

  A cooling fan 7 is disposed between the circulation fan case 60 and the motor 4. The cooling fan 7 is fixed to an intermediate portion in the axial direction of the rotating shaft of the motor 4. Between the cooling fan 7 and the motor 4, A cooling fan case 41 having a rear surface having an opening 41a in the center for cooling the motor 4 by the rotation of the cooling fan 7 is disposed. Further, the bottom surface and both side surfaces of the cooling fan case 41 are joined and closed with the circulation fan case 60, but the upper portion of the cooling fan case 41 is opened upward to discharge the cooling air to the outside. . The rear of the upper opening portion extends beyond the motor chamber 40 and is connected to a passage member 81 that opens toward the exhaust port 50. As a result, a motor chamber 40 in which the motor 4 is accommodated at the upstream end and a cooling passage 8 that communicates with the exhaust port 50 at the downstream end and discharges the cooling air after cooling the motor 4 from the exhaust port 50 to the outside are formed. Is done.

  The cooling passage 8 communicates with the motor chamber 40 via the opening 41 a of the cooling fan case 41, but is separated from the circulation passage 61 by the circulation fan case 60 so as to be disconnected. The cooling air is configured not to be sent into the hot air passage 44. Thereby, the temperature fall of the hot air by cooling air is prevented.

  As described above, the exhaust passage 5 communicating with the exhaust outlet 33a and the exhaust port 50 is formed at the upper rear of the upper wall 33 constituting the ceiling portion of the heating chamber 3a. The exhaust passage 5 is opposed to the rear upper wall 33 with a predetermined interval and spaced apart, and further extends rearward in the horizontal direction, and is bent and extends obliquely upward toward the upper exhaust port 50; From the upper surface of the circulation fan case 60 connected to the upper peripheral edge of the rear wall 36 of the heating chamber 3a, it extends in the horizontal direction beyond the upper side of the cooling passage 8 and is bent and slanted toward the upper exhaust port 50. It is comprised from the partition plate 52 extended upwards. The upper end of the partition plate 52 forms a downstream end of the exhaust passage 5 and a downstream end of the cooling passage 8. The downstream end of the exhaust cover 51 that forms the upper portion of the exhaust passage 5 and the downstream end of the passage member 81 that forms the lower portion of the cooling passage 8 are connected to a cylindrical exhaust duct 9 that forms the exhaust port 50. . Thus, the cooling passage 8 is disposed in a state of being separated and separated from the exhaust passage 5 by the partition plate 52, and the exhaust from the exhaust passage 5 and the cooling air from the cooling passage 8 are They merge on the downstream side of the downstream ends of the passages 5 and 8 and are discharged to the outside through a single exhaust port 50.

  Accordingly, when the object to be cooked is accommodated in the heating chamber 3a and the circulation fan 6 is rotationally driven by the motor 4, external air is taken in. In this state, when the gas is supplied to the oven burner 43 and ignited, the oven burner 43 The hot air of the combustion exhaust gas generated in step 1 is sent into the heating chamber 3a, and the hot air starts to circulate in the heating chamber 3a forcibly. During oven cooking, while the circulation fan 6 is rotating, outside air is taken into the combustion chamber 3b, so that a part of the hot air in the heating chamber 3a includes oil smoke generated from the object to be cooked. As described above, the gas is discharged from the exhaust outlet 33a of the upper wall 33 to the exhaust passage 5.

  The control device C according to the present embodiment is a control unit including a microcomputer including a CPU, a timer, a memory, and the like. As illustrated in FIG. Electrical wiring with switch S1, cooking start switch S2, ignition electrode P1, thermocouple P2, source gas solenoid valve V1, safety valve V2, flow rate adjustment valve V3, motor 4, motor room temperature sensor 48, rotation sensor 63, speaker S, etc. It is connected. Further, as shown in FIG. 3, the control device C is provided in a gas supply pipe that supplies gas to the oven burner 43 so that oven cooking is performed under the cooking conditions set by the cooking menu switch S1. Actuator control unit 101 that controls the supplied gas solenoid valve V1, safety valve V2, and flow rate adjustment valve V3 to adjust the gas supply amount, ignition unit 102 that causes spark discharge from the ignition electrode P1, and thermoelectromotive force of the thermocouple P2 An ignition detection unit 103 that determines whether or not a predetermined ignition detection level, a misfire detection unit 104 that determines whether or not the thermoelectromotive force of the thermocouple P2 after ignition is at a predetermined misfire detection level, and a circulation fan 6 A drive control unit 105 that drives the motor 4 to rotate at a predetermined rotational speed, and a drive that detects motor power when the circulation fan 6 is rotationally driven at a predetermined rotational speed. When the rotational speed of the circulation fan 6 stored in the memory M, which will be described later, and the motor power detected by the characteristic detection unit 106 and the drive characteristic detection unit 106 and the fluctuation range of the motor power within a predetermined time is rotated at a predetermined rotational speed A fan state determination unit 107 that determines the rotational state of the circulation fan 6 by comparing the threshold value of the motor power associated with the temperature in the vicinity of the motor 4 and the threshold value of the fluctuation range of the motor power within a predetermined time. When the determination unit 107 detects the rotation abnormality of the circulation fan 6 a predetermined number of times, the operation prohibition unit 108 that makes the appliance interlocked, and the rotation abnormality of the circulation fan 6 are detected, the fan S from the speaker S Is provided.

  In addition, the memory M stores a cooking program including setting of heating power and cooking time according to cooking conditions, and a determination program for determining rotation abnormality of the circulation fan 6. Further, in the memory M, the motor power corresponding to the set value of the thermoelectromotive force of the thermocouple P2 for determining the ignition condition and the misfire condition and the temperature in the vicinity of the motor 4 for determining the rotation state of the circulation fan 6 is stored. And a data table including a threshold value of the fluctuation range of the motor power within a predetermined time.

  FIG. 4 is a correlation diagram illustrating the relationship between the motor power and the temperature in the vicinity of the motor 4 in the cooking device of the present embodiment. In FIG. 4, the solid line indicates that the rotation speed of the circulation fan 6 detected by the rotation sensor 63 is a constant rotation speed (for example, 220 Hz) in a state where the circulation fan 6 is normally fixed to the rotation shaft of the motor 4. Thus, the transition of the motor power when the circulation fan 6 is rotationally driven is shown. As shown in the figure, when the circulation fan 6 is rotationally driven in a state where the circulation fan 6 is normally fixed to the rotation shaft of the motor 4, a constant motor power is detected. Further, since the resistance changes as the temperature in the vicinity of the motor 4 increases, the load decreases, and even if the circulation fan 6 is driven to rotate at the same rotational speed, the motor power gradually decreases as the temperature increases. On the other hand, in FIG. 4, the crosses indicate motor power when the circulation fan 6 is idling. As shown in the figure, when the circulation fan 6 is idling, the load on the rotating shaft of the motor 4 is eliminated, so that the motor power is significantly reduced. Similarly to the normal fixed state, the motor power decreases as the temperature near the motor 4 increases. For this reason, in the present embodiment, in order to determine whether or not the circulation fan 6 is idling, the threshold of the motor power associated with the temperature in the vicinity of the motor 4 indicated by the broken line in FIG. Stored in M.

  Note that a motor power threshold value for determining the rotation state of the circulation fan 6 can be set regardless of the temperature in the vicinity of the motor 4. However, as understood from FIG. 4, the motor power may fluctuate greatly depending on the temperature characteristics of the motor 4. Accordingly, if a higher motor power threshold is set to determine the rotation abnormality in the low temperature atmosphere at an early stage, even if the circulation fan 6 is normally driven to rotate in the high temperature atmosphere, the motor power is reduced. May be judged. Also, if a lower motor power threshold is set in order to determine the rotation abnormality in the high temperature atmosphere, the rotation abnormality will not occur unless the motor power when the circulating fan 6 is normally driven to rotate is greatly reduced in the low temperature atmosphere. May not be detected. Therefore, by setting a motor power threshold value corresponding to the temperature in the vicinity of the motor 4, it is possible to reliably determine the rotation abnormality of the circulation fan 6 at an early stage both at the start of cooking and during the cooking. Can do.

  FIG. 5 shows motor power when the circulation fan 6 is rotationally driven at a predetermined rotational speed at a constant temperature (about 70 ° C.) after a predetermined time has elapsed since the start of the oven cooking. In FIG. 5, the solid line indicates the transition of the motor power when the circulation fan 6 is normally fixed to the rotating shaft of the motor 4. As shown in the figure, since the circulation fan 6 is driven to rotate at a predetermined rotational speed, the fluctuation of the motor power is small in a normal fixed state. On the other hand, the broken line in FIG. 5 shows the transition of the motor power when the circulation fan 6 is temporarily idle. As shown in the figure, when the circulation fan 6 is temporarily idled and the rotational speed fluctuates, the motor 4 performs correction to maintain the predetermined rotational speed, and the motor power fluctuates. Therefore, by detecting the fluctuation range of the motor power within a short time, for example, the circulation fan 6 is not in a state of dropping from the rotating shaft of the motor 4, but a partial deficiency has begun to occur in the connection between the two. Temporary rotation abnormality can be determined. For this reason, in the present embodiment, the threshold value (for example, 2 W) of the fluctuation range of the motor power within a predetermined time is stored in the memory M described above.

  Next, an example of the control operation in the case of performing oven cooking using the heating cooker of the present embodiment will be described based on the flowcharts shown in FIGS.

  To perform oven cooking, the user rotates the door 32 forward, places an object to be cooked such as fish or meat on the plate 13 taken out from the heating chamber 3a, and rotates the door 32 backward. Then, after closing the front opening part of the heating chamber 3a, when the point fire extinguishing switch 70 is pressed (step ST1), power is supplied from the power supply circuit and the control device C starts operating, and the original gas solenoid valve V1 is opened (step ST2). Then, when the user selects, for example, a fish dish from the cooking menu and turns on the cooking start switch S2 with the operation unit (step ST3), an on signal is input to the control device C to start the timer. Then, the pre-purge for driving the motor 4 and rotating the circulation fan 6 at a predetermined pre-purge rotation speed (for example, 200 Hz) is performed (step ST4).

  In this pre-purge, when driving of the motor 4 is started, it is determined whether or not the motor power Wx is equal to or greater than a predetermined motor power threshold Wp for a predetermined pre-purge time Tp (for example, 7 seconds) (steps ST5 to ST6). ). If the motor power Wx is less than the predetermined motor power threshold Wp within the predetermined pre-purge time Tp (No in step ST5), there is a possibility that rotation abnormality due to idling of the circulation fan 6 has occurred. Energization of the motor 4 is stopped (step ST17), and a fan error is notified from the speaker S or the like without igniting the oven burner 43 (step ST18). Thereby, oven cooking can be prevented from starting in a state where the circulation fan 6 does not rotate normally.

  Next, 1 is added to the fan error frequency E (step ST19), and the total fan error frequency E combined with the fan error frequency when determining the rotation abnormality of the circulation fan 6 described later is a predetermined number Ea (for example, When counted five times (Yes in step ST20), the control device C puts the appliance in an interlock state in order to disable oven cooking from the next time (step ST21).

  On the other hand, when it is detected that the motor power Wx is equal to or greater than the predetermined motor power threshold Wp within the pre-purge time Tp (Yes in step ST5), the circulating fan 6 is rotated at a predetermined cooking speed (for example, 220 Hz). ) To drive the motor 4 (step ST7).

  Next, it is determined whether or not the motor power Wx is equal to or greater than a predetermined motor power threshold Ws (step ST8), and the motor power fluctuation width Lx within the start check time Ts (for example, 5 seconds) is the fluctuation width threshold. It is determined whether or not Ls or less (step ST9).

  Whether the motor power Wx is less than the motor power threshold Ws within the predetermined start check time Ts (No in step ST8) or the motor power fluctuation width Lx within the start check time Ts is greater than the fluctuation width threshold Ls. If it becomes larger (No in step ST9), there is a possibility that a rotation abnormality has occurred in the circulation fan 6. Therefore, as in the case of the pre-purge described above, the energization to the motor 4 is stopped and the oven burner 43 is turned off. Without ignition, a fan error is notified from the speaker S or the like, and the addition of the number of fan errors and the total number of fan errors are confirmed (steps ST17 to ST21).

  On the other hand, when the motor power Wx is not less than the motor power threshold Ws and the motor power fluctuation width Lx is not more than the fluctuation width threshold Ls within a predetermined start check time Ts (Yes in steps ST8 and ST9), The safety valve V2 and the flow rate adjustment valve V3 are opened, and the ignition of the oven burner 43 is started by causing a spark discharge from the ignition electrode P1 (step ST11).

  Next, the thermocouple P2 is burned by the combustion flame of the oven burner 43, and it is determined whether the thermoelectromotive force output from the thermocouple P2 is at a predetermined ignition detection level (step ST12), and predetermined ignition is performed. If the thermoelectromotive force reaches the ignition detection level within time Ta (for example, 7 seconds) (Yes in step ST12), the discharge from the ignition electrode P1 is stopped (step ST13). When the thermoelectromotive force is not at a predetermined ignition detection level (No in step ST12, Yes in step ST14), an ignition error is notified from the speaker S or the like, and the discharge from the ignition electrode P1 is stopped, and the original gas The solenoid valve V1, the safety valve V2, and the flow rate adjustment valve V3 are closed to stop ignition of the oven burner 43 and stop energization of the motor 4 (steps ST15 to ST16).

  When the oven burner 43 is ignited, as shown in FIG. 7, it is continuously determined during cooking whether the thermoelectromotive force detected by the thermocouple P2 is at a predetermined misfire detection level (step). ST22) When the thermoelectromotive force reaches a predetermined misfire detection level during cooking (Yes in step ST22), a misfire error is notified from the speaker S or the like, and the original gas solenoid valve V1, safety valve V2, and flow rate adjustment are performed. The valve V3 is closed, the combustion of the oven burner 43 is stopped, and the energization to the motor 4 is stopped (steps ST26 to ST27).

  When the oven burner 43 is burning during cooking, the motor 4 is driven so that the circulation fan 6 is driven to rotate at a predetermined rotational speed. Then, it is determined whether or not the motor power Wx is equal to or greater than a predetermined motor power threshold Ws based on the temperature in the vicinity of the motor 4 (step ST23), and further, the fluctuation range of the motor power within a predetermined time (for example, 30 seconds). It is determined whether or not Lx is equal to or less than the fluctuation range threshold Ls (step ST24).

  During cooking, if the motor power Wx becomes less than the motor power threshold Ws (No in step ST23), or if the motor power fluctuation width Lx within a predetermined time becomes larger than the fluctuation width threshold Ls (in step ST24, No), because there is a possibility that the rotation abnormality of the circulation fan 6 has occurred, the original gas solenoid valve V1, the safety valve V2, and the flow rate adjustment valve V3 are closed to stop the combustion of the oven burner 43, The energization to the motor 4 is stopped (step ST28). Then, as in the case of the pre-purge described above, the fan error is notified from the speaker S and the like, and the addition of the fan error count and the total fan error count are confirmed (steps ST18 to ST21).

  During cooking, when the cooking time Tb ends without detecting the rotation abnormality of the circulation fan 6 (Yes in step ST25), the original gas solenoid valve V1, the safety valve V2, and the flow rate adjustment valve V3 are closed, and the motor 4 is stopped (step ST27).

  When the circulation fan 6 is slipping off from the rotating shaft of the motor 4 and so on, the load on the motor 4 is reduced. Therefore, the driving characteristics such as motor power are normally fixed to the rotating shaft of the motor 4. It is different from that when it is. Accordingly, a temperature sensor or the like that detects the temperature in the vicinity of the circulation fan 6 by detecting the drive characteristics of the motor 4 that rotationally drives the circulation fan 6 and comparing the drive characteristics with a threshold value of the predetermined drive characteristics is used. The rotation state of the circulation fan 6 can be determined early. Thereby, generation | occurrence | production of noise, the combustion failure of the oven burner 43, and the local overheating of an instrument can be prevented.

  Further, since the drive characteristics of the motor 4 may vary depending on the temperature in the vicinity of the motor 4, the motor can be driven even when the circulating fan 6 is rotationally driven at the same rotational speed in the low temperature atmosphere at the start of cooking and the high temperature atmosphere during cooking. 4 has different driving characteristics. However, according to the heating cooker, when the rotational state of the circulation fan 6 is determined, the drive characteristic threshold value associated with the temperature in the vicinity of the motor 4 is used. Can be determined.

  Further, when the circulation fan 6 is rotationally driven at a predetermined rotational speed, the fluctuation range of the drive characteristics of the motor 4 is small if the circulation fan 6 is normally fixed to the rotation shaft of the motor 4. However, if there is a partial deficiency in the connection between the circulation fan 6 and the rotating shaft of the motor 4, the circulation fan 6 may be temporarily idle. When the drive of the motor 4 is controlled so that the circulation fan 6 is driven to rotate at a predetermined rotational speed, when the rotation abnormality occurs in the circulation fan 6, the drive of the motor 4 is corrected so as to recover the predetermined rotational speed. Therefore, drive characteristics such as motor power fluctuate greatly within a short time. Therefore, by comparing the fluctuation range of the drive characteristic within the predetermined time and the threshold value of the fluctuation range of the drive characteristic, a temporary rotation abnormality can be detected at an early stage.

  In the heating cooker, not only during cooking but also in the pre-purge before the oven burner 43 is ignited, the rotational speed is changed and rotation abnormality of the circulation fan 6 is detected. It is possible to reliably check whether or not the connection with the rotary shaft is defective, and cooking can be stopped without igniting the oven burner 43. Further, when the rotation abnormality of the circulation fan 6 is detected a predetermined number of times, the appliance is set in the interlock state, and the next cooking is prohibited, so that the cooking is started without the circulation fan 6 rotating normally. Can be prevented. Thereby, higher safety can be ensured.

  In determining the rotation state of the circulation fan 6, the motor power threshold Wp in the pre-purge and the motor power threshold Ws in the start check are repeatedly heated by using a set value associated with the temperature in the vicinity of the motor 4. Even when cooking is performed using the chamber 3a, the rotation abnormality of the circulation fan 6 can be reliably detected.

(Other embodiments)
(1) In the above embodiment, the motor drive is controlled so that the rotation speed of the circulation fan detected by the rotation sensor becomes a predetermined rotation speed. However, the rotation speed and motor of the circulation fan in a normal fixed state are controlled. The motor may be driven without detecting the rotational speed of the circulation fan by obtaining the relationship with the drive characteristic in advance.

(2) In the above embodiment, the motor is driven so that the circulation fan is rotated at a predetermined rotation number during cooking in the oven. However, even if the rotation number of the circulation fan is changed depending on the cooking time and cooking temperature. Good. For example, the circulation fan may be rotationally driven at a high rotational speed at the beginning of cooking, and the circulation fan may be rotationally driven at a low rotational speed at the end of cooking. In this case, the memory stores the threshold value of the drive characteristic and the threshold value of the fluctuation range corresponding to each rotation speed.

(3) In the above embodiment, the circulation fan is always driven to rotate during the cooking of the oven. However, when the oven burner is extinguished and the temperature is controlled, the circulation fan is stopped when the oven burner is extinguished. You may keep it.

(4) In the above embodiment, the motor power is used as the motor drive characteristic to determine the rotation state of the circulation fan. However, the drive characteristic varies depending on the motor load as with the motor power. Any of current and motor voltage, or a combination of these may be used.

(5) In the above embodiment, the rotation abnormality of the circulation fan is determined on the basis of the drive characteristics when the circulation fan idles with respect to the rotation shaft of the motor. The rotation abnormality of the circulation fan may be determined on the basis of the drive characteristics in the case where the temperature decreases or does not rotate. In this case, since the motor load increases compared to when the circulation fan is rotating normally, the rotation of the circulation fan is determined based on whether the motor power exceeds a predetermined motor power threshold, contrary to the case of idling. The state can be determined.

(6) In the above embodiment, a suction-type circulation fan is used. However, a push-type circulation fan may be used.

3a Heating chamber 43 Oven burner 4 Motor 6 Circulating fan 48 Motor chamber temperature sensor (temperature detector)
63 Rotation sensor (Rotation speed detector)
105 drive control unit 106 drive characteristic detection unit 107 fan state determination unit 108 operation prohibition unit C control unit M memory (storage unit)

Claims (7)

An oven burner that generates hot air by burning gas,
A heating chamber for heating the cooking object;
A circulation fan for sending and circulating hot air generated by the oven burner to the heating chamber;
A motor that rotationally drives the circulation fan;
A heating cooker having a control device capable of determining rotation abnormality of the circulation fan,
The controller is
A drive control unit for controlling the drive of the motor;
A drive characteristic detector for detecting the drive characteristic of the motor;
A storage unit that stores a threshold value of a driving characteristic of the motor for determining a rotation state of the circulation fan;
A heating cooker having a fan state determination unit that determines a rotation state of the circulation fan by comparing the drive characteristic detected by the drive characteristic detection unit with a threshold value of the drive characteristic. The heating cooker according to claim 1, wherein
A temperature detection unit for detecting a temperature in the vicinity of the motor;
The cooking device in which the storage unit stores a threshold value of driving characteristics of the motor associated with a temperature in the vicinity of the motor. The heating cooker according to claim 1 or 2,
A rotation number detection unit for detecting the rotation number of the circulation fan;
The said drive control part is a heating cooker which controls the drive of the said motor so that the rotation speed of the said circulation fan detected by the said rotation speed detection part is maintained by predetermined rotation speed. The cooking device according to claim 3,
In the storage unit, a threshold value of the fluctuation range of the drive characteristics of the motor within a predetermined time is stored,
The said fan state determination part is a heating cooker which determines the rotation state of the said circulation fan by contrasting the fluctuation range of the drive characteristic of the said motor within the predetermined time, and the threshold value of the said fluctuation range. In the heating cooker according to any one of claims 1 to 4,
The drive characteristic detector is a cooking device that detects at least one drive characteristic selected from the group consisting of motor power, motor current, and motor voltage. In the cooking-by-heating machine of any one of Claims 1-5,
The fan state determination unit is a heating cooker that determines idling and / or sticking of the circulation fan. In the heating cooker according to any one of claims 1 to 6,
The control device further includes an operation prohibition unit that sets the appliance in an interlock state in order to prohibit cooking after the next time when the rotation abnormality of the circulation fan is detected a predetermined number of times in the fan state determination unit. Cooking device.

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