JP2537565B2 - Heating cooker - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a heating cooker that controls heating based on signals from various sensors.

[Prior art]

Conventionally, in a microwave oven having a toast function (hereinafter referred to as a toaster range), a detection circuit using various sensors is attached and heating control is performed based on a signal from the detection circuit in order to reduce the price. Was not done very well. However, since the gourmet boom in recent years, fine heating control is desired even in a toaster range for general household use, and a toaster range as shown in FIG. 8 is emerging. In the toaster range described above, the humidity sensor 1 for detecting the humidity inside the chamber due to the water vapor generated from the food during heating is installed inside the exhaust port 4 of the heating chamber 3. Then, the humidity detection circuit using the humidity sensor 1 detects the amount of water vapor when the water vapor generated from the food along with the heating of the food is discharged from the exhaust port 4 to the outside of the refrigerator. Further, the optical sensor 2 for detecting the burnt condition of the food is supported by the cylindrical support 5 and the heating chamber 3
It is installed on the side wall 3a. Then, when the heating of the food is started and the food placed on the turntable 7 is irradiated by the oven lamp 6 for the interior lighting, the reflected light from the food is received by the optical sensor 2, and the food surface The degree of scorch of food is detected by the change in illuminance. Thus, the humidity detection signal representing the humidity detected by the humidity detection circuit using the humidity sensor 1 and the illuminance detection signal representing the illuminance detected by the illuminance detection circuit using the optical sensor 2 are illustrated via the lead wires. Not sent to the microcomputer. Then, the microcomputer controls the heat treatment of the food according to the amount of water vapor released from the food and the degree of charring of the food based on the input detection signal.

[Problems to be Solved by the Invention]

By the way, no weight sensor is installed in the toaster range. Therefore, if there is no way to detect that no food is placed on the turntable 7, and if the heating process is performed without forgetting to put the food on the turntable 7, no load heating is performed. The abnormal heating state continues. In such a case, there is a problem that the toaster range is damaged or the user is burned. Further, the operation panel of the toaster range is usually provided on the front side of the toaster range main body on the right side of the oven door. Then, the magnetron 8, the oven lamp 6, and the electrical components that radiate microwaves during microwave heating are installed in the space behind the operation panel. On the contrary,
The exhaust port 4 is provided on the side wall 3b opposite to the operation panel so as not to interfere with the magnetron 8, the oven lamp 6 and electrical components. However, the above conventional humidity sensor 1 and optical sensor 2
In the toaster range equipped with, the humidity sensor 1 is installed inside the exhaust port 4. On the other hand, a microcomputer for controlling heating is usually installed near the operation panel. Therefore, the humidity sensor 1 and the microcomputer are on the opposite sides of the heating chamber 3 so that the lead wire from the humidity sensor 1 to the microcomputer becomes long. For this reason, it is necessary to consider that the lead wire does not come into contact with a high temperature portion such as the exhaust port 4 formed of metal, and there is a problem that the wiring is troublesome. Furthermore, in order to protect the detection signal from the humidity detection circuit using the humidity sensor 1 from noise, a long lead wire must be shielded, which causes a problem of high cost. Another object of the present invention is to provide a heating cooker that can detect a no-load heating state without a weight sensor, and that has a simple and inexpensive wiring for various sensors.

[Means for Solving the Problems]

In order to achieve the above object, a first invention is a heating means,
Having heating control means, light detection means and humidity detection means,
Based on the illuminance of the reflected light from the surface of the object to be heated detected by the light detection means and the humidity in the heating chamber detected by the humidity detection means, heating for executing the control of the heating means by the heating control means In the cooker, receiving an illuminance detection signal representing the illuminance of reflected light from the surface of the object to be heated detected by the light detection means and a humidity detection signal representing the humidity in the heating chamber detected by the humidity detection means, Based on the change amount of the illuminance detection signal within a predetermined time and the change amount of the humidity detection signal within a predetermined time, a no-load heating state in which a heating process is performed in a state where there is no object to be heated in the heating chamber. A no-load heating state detecting means for detecting, and a heating stopping means for stopping the heating means when the no-load heating state detecting means detects the no-load heating state. It is characterized in that was example. In a second aspect of the invention, in the heating cooker according to the first aspect of the invention, the light detecting means, the humidity detecting means, the heating control means, and the no-load heating state detecting means are arranged on the same side with respect to the heating chamber. Is characterized by.

[Action]

In the first invention, the illuminance detection signal representing the illuminance of the reflected light from the surface of the object to be heated and the humidity detection signal representing the humidity in the heating chamber are detected by the light detecting means and the humidity detecting means, and are detected. The illuminance detection signal and the humidity detection signal are input to the heating control means. Then, the heating control means controls the heating means according to the illuminance of the reflected light from the surface of the object to be heated and the humidity in the heating chamber. Further, the illuminance detection signal detected by the light detection means and the humidity detection signal detected by the humidity detection means are input to the no-load heating state detection means. Then, based on the amount of change in the illuminance detection signal within a predetermined time period and the amount of change in the humidity detection signal within a predetermined time period, the no-load heating state detection means heats the object without heating the heating chamber. The no-load heating state in which the process is executed is detected. When the no-load heating state detecting means detects the no-load heating state, the heating stopping means stops the heating means. Further, in the second invention, the light detecting means, the humidity detecting means, the heating control means and the no-load heating state detecting means in the first invention are arranged on the same side with respect to the heating chamber. The distances between the means and the heating control means, between the humidity detection means and the heating control means, between the light detection means and the no-load heating state detection means, and between the humidity detection means and the no-load heating state detection means are Short and easy to wire.

【Example】

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a cross-sectional view in which the outer shell of a toaster range which is the heating cooker of the present invention is removed. On the ceiling 12 of the heating chamber 11 formed by a box made entirely of metal, as a heating means for heating an object to be heated placed on the turntable 21 at the time of toast heating or the like. Book electric heaters 14 and 15 are installed in parallel. Further, a waveguide 18 extending rightward in the drawing and passing through the heating chamber 11 is provided above the ceiling 12 of the heating chamber 11, and a magnetron 17 as heating means is installed in the waveguide 18. To do. And, at the time of microwave heating, the microwave radiated from the magnetron 17 is
The object to be heated placed on the turntable 21 is irradiated through the waveguide 18. When the object to be heated is heated by the heating by the electric heaters 14 and 15 or the microwave, the water vapor generated from the object is discharged from the exhaust port 19 to the outside of the heating chamber 11. Below the side wall 13 on the right side of the heating chamber 11 in the drawing, an oven lamp 16 for irradiating the inside of the heating chamber 11 with visible light is installed. Further, above the oven lamp 16, an optical sensor 22 for detecting a change in illuminance of visible light emitted from the oven lamp 16 and reflected on the surface of the object to be heated as a change in the degree of burning on the surface of the object to be heated. Also, a humidity sensor 23 for detecting a change in humidity in the heating chamber 11 as a change in the amount of water vapor released from the object to be heated is installed. here,
The optical sensor 22 and the humidity sensor 23 are connected to the side wall 13 as follows.
Installed in That is, the optical sensor 22 receives only the visible light reflected by the surface of the object to be heated among the visible light emitted from the oven lamp 16 installed on the side wall 13, in order to have directivity. Cylindrical support made of resin
It is supported by the bottom of 24 and installed on the side wall 13 of the heating chamber 11 so as to face the center of the turntable 21. Thus, the optical sensor 22 is installed on the same side wall 13 as the oven lamp 16 in order to efficiently receive the reflected light from the object to be heated. On the other hand, the humidity sensor 23, as shown in FIG.
The optical sensor 22 is inserted from the outside into the hole 24a formed in the side wall of the support tool 24 attached to one end and attached. At that time, the inner surface of the support 24 and the head of the humidity sensor 23 are generally arranged so that the head of the humidity sensor 23 does not project into the support 24 and block visible light from the surface of the object to be heated toward the optical sensor 22. They are attached so that they are in the same position. In this way, by mounting the humidity sensor 23 on the resin support 24, it is possible to prevent temperature drift of the humidity sensor 23 due to heat transmitted from the metal side wall 13. The optical sensor 22 and the humidity sensor 23 installed on the side wall 13 of the heating chamber 11 as described above are connected to the control board as follows. FIG. 2 is a partial plan view of FIG. Second
As shown in the figure, an oven door 25 is installed in front of the heating chamber 11. Further, on the right side of the oven door 25 (that is, in front of the heating chamber 11 on the outside on the right side in the drawing), there are provided operation keys for inputting various heating conditions and the like, a display screen for displaying the set conditions and the like. The operation panel 26 is installed. Then, on the back surface of the operation panel 26, a microcomputer for executing various controls such as heating control, an illuminance detection circuit for incorporating an illuminance detection signal from the optical sensor 22 into the microcomputer, and a humidity from the humidity sensor 23. A control board 27 having a humidity detection circuit and the like for taking the detection signal into the microcomputer is arranged. Then, the connector 30 of the control board 27 and the connector of the optical sensor 22 are connected by the lead wire 28. Similarly, the connector 31 of the control board 27 and the connector of the humidity sensor 23 are connected by the lead wire 29. At this time, both the optical sensor 22 and the humidity sensor 23 are attached to the support tool 24, and the support tool 24 is attached to the outside of the right side wall 13 of the heating chamber 11 (that is, the control board 27).
It is installed so as to project into the space behind. Therefore,
The distance between the optical sensor 22 and the control board 27 and the distance between the humidity sensor 23 and the control board 27 are short, the length of the lead wire 28 connecting the optical sensor 22 and the control board 27, and the humidity sensor 23 and the control board 27. It is possible to shorten the length of the lead wire 29 for connecting the. Here, since the water vapor released from the object to be heated at the time of heating diffuses evenly throughout the heating chamber 11, the humidity sensor 23 is attached to the support 24 for supporting the optical sensor 22 without installing it in the exhaust port 19. However, there is no problem in detecting water vapor released from the object to be heated. In this embodiment, based on the illuminance detection signal from the illuminance detection circuit using the optical sensor 22 and the humidity detection signal from the humidity detection circuit using the humidity sensor 23, no-load heating is performed as described below. If it detects a condition,
The heat treatment is stopped. FIG. 4 is a circuit diagram of the heating control circuit. In FIG. 4, for example, a "toaster" key 41 which is one of the operation keys provided on the operation panel 26 is pressed. Then, the microcomputer formed on the control board 27
A toast heating signal is output from 42, the transistor 43 turns on, the relay coil R ₁ is excited, and the normally open contact is generated.
r ₁ turns “on”. As a result, the motor 20 for rotating the electric heaters 14 and 15 and the turntable 21 is driven, the oven lamp 16 is turned on, and the toast heating operation is started. On the other hand, for example, the "range" key 44 is pressed. Then, a range heating signal is output from the microcomputer 42, the transistor 45 is turned on, the relay coil R ₂ is excited, and the normally open contact r ₂ is turned on. As a result, the magnetron 17 and the motor 20 are driven, the oven lamp 16 is turned on, and the microwave heating operation is started. When the heating process operation is started in this manner, the microcomputer 42 executes heating control based on the detection signals input from the optical sensor 22 and the humidity sensor 23 via the lead wires 28 and 29. Further, the microcomputer 42
Based on the detection signals from the optical sensor 22 and the humidity sensor 23, the no-load heating control operation is executed as described later in detail.
That is, the microcomputer 42 constitutes the heating control means, the no-load heating state detection means, and the heating stop means. The no-load heating control operation executed by the microcomputer 42 is performed based on the following facts. That is, FIG. 5 shows the fluctuation of the output value (illuminance detection signal) output from the optical sensor 22 to the microcomputer 42 (that is, the fluctuation of the illuminance on the surface of the object to be heated). In the figure, the solid line is the output value when the object to be heated is placed on the turntable 21 and the heating process is performed, and the output is generated as the object to be heated rotates because the surface of the object to be heated is uneven. Values show periodic fluctuations. On the other hand, the broken line is the output value in the so-called no-load heating state in which the heating process is performed without placing anything on the turntable 21, and since the surface of the turntable 21 is flat, even if the turntable 21 rotates, The output value hardly changes. FIG. 6 shows a manual force value (humidity detection signal) output from the humidity sensor 23 to the microcomputer 42.
(That is, fluctuations in the amount of water vapor released from the object to be heated). In the figure, the solid line is the output value in the heat treatment state in which there is an object to be heated, and the output value rises as steam is released from the object to be heated. On the other hand, the broken line is the output value in the no-load heating state, and since the steam is not generated, the output value hardly changes. Therefore, the microcomputer 42 sets the maximum value Vmax of the output value from the optical sensor 22 from the start of the heating process to the elapse of the predetermined time T and the minimum value Vmin from the elapse of the predetermined time T to the further elapse of the predetermined time ΔT. Difference value and the initial value V ₀ from the humidity sensor 23 at the start of the heat treatment and the output value V after the elapse of a predetermined time T.
Based on the value of the difference from T, it is determined whether or not there is a no-load heating state. FIG. 7 is a flowchart of the no-load heating control operation executed by the microcomputer 42. Hereinafter, the no-load heating control operation will be described in detail with reference to FIG. The maximum value Vmax, the minimum value Vmin, the initial value V _0, and the output value VT in a memory (not shown) that holds the illuminance detection value based on the optical sensor 22 and the humidity detection value based on the humidity sensor 23 are initialized to _zero. The load heating control processing operation starts. In step S1, the initial value (output value at the start of the heating process) V ₀ of the output value from the humidity sensor 23 is read and stored in the memory (not shown). In step S2, the output value from the optical sensor 22 is read. Then, the read output value and the maximum value Vmax of the output value from the optical sensor 22 stored in the memory are compared, and if the maximum value Vmax is smaller, the content of the maximum value Vmax is read. Updated by value. In step S3, a predetermined time T has elapsed since the heat treatment was started.
Is determined. If the result has passed, the process proceeds to step S4, and if not, the process returns to step S2 to read the output value from the optical sensor 22 and set the maximum value Vmax.
Will continue to be updated. That is, the maximum value Vmax of the output value from the optical sensor 22 within the predetermined time T from the start of the heating process is obtained and stored in the memory. In step S4, the output value VT from the humidity sensor 23 is read and stored in the memory. In step S5, the output value from the optical sensor 22 is read. Then, the read output value and the minimum value Vmin of the output value from the optical sensor 22 stored in the memory are compared, and if the minimum value Vmin is larger, the content of the minimum value Vmin is read. Value is updated. In step S6, it is determined whether or not a predetermined time (T + ΔT) has elapsed since the heating process was started. If the result has passed, the process proceeds to step S7, and if not, the process returns to step S5 and the reading of the output value from the optical sensor 22 and the updating of the minimum value Vmin accompanying it are continued. That is, the minimum value Vmin of the output values from the optical sensor 22 at the predetermined time ΔT is obtained and stored in the memory. At step S7, the initial value V ₀ of the output value from the humidity sensor 23 stored at step S1 and the output value VT stored at step S4 are read from the memory, and the following equation is satisfied? It is determined whether or not. VT <T ₀ + α If the result is satisfied, the process proceeds to step S8, and if not, the process proceeds to step S10. In step S8, the maximum value Vmax from the optical sensor 22 stored in step S2 and the minimum value Vmin stored in step S5 are read from the memory,
It is determined whether or not the following expression holds. Vmax−Vmin <β If the result is satisfied, the process proceeds to step S9, and if not, the process proceeds to step S10. In step S9, the value of the difference between the maximum value Vmax and the minimum value Vmin of the output value of the optical sensor 22 is smaller than the predetermined value β,
Moreover, since the difference value between the output value VT and the initial value V ₀ in the humidity sensor 23 is smaller than the predetermined value α, it is determined that nothing is placed on the turntable 21. That is, in this case, since the heating process is in the no-load heating state, the toast heating signal or the range heating signal is stopped and the transistor 43 or the transistor is turned off.
45 turns “off”. In this way, the heat treatment operation is stopped, and the no-load heating control operation is ended. In step S10, the difference between the maximum value Vmax and the minimum value Vmin of the output value of the optical sensor 22 is not less than the predetermined value β, and the output value VT of the humidity sensor 23 and the initial value V ₀
Since the value of the difference between and is greater than or equal to the predetermined value α, it is determined that the heating process is not in the no-load heating state. Therefore, the heat treatment operation is continued to end the no-load heating control operation. As described above, in the present embodiment, when the difference value between the maximum value Vmax and the minimum value Vmin of the output value of the optical sensor 22 is smaller than the predetermined value β, the output value VT and the initial value of the humidity sensor 23 are set. By determining the no-load heating state only when both the case where the value of the difference from V ₀ is smaller than the predetermined value α are compatible, the malfunction described below is prevented. That is, when determining the no-load heating state based only on the humidity detection signal from the humidity sensor 23, if the object to be heated is, for example, a frozen pan, the time generated from the steam from the object to be heated is more than that of a normal bread. Since it is late, the solid line in FIG. 6 is closer to the broken line. Therefore, it may be determined in step S7 that the vehicle is in the no-load heating state even though it is not in the no-load heating state. On the other hand, when determining the no-load heating state based only on the illuminance detection signal from the optical sensor 22, if the object to be heated is, for example, a blackish bread, the amount of light reflected from the object to be heated is small The solid line in FIG. 5 is closer to the broken line. Therefore, it may be determined in step S8 that the vehicle is in the no-load heating state even though it is not in the no-load heating state. From the above, malfunction is prevented by determining the no-load heating state based on both the illuminance detection signal from the optical sensor 22 and the humidity detection signal from the humidity sensor 23. As described above, in the present embodiment, the optical sensor 22 is installed on the side wall 13 of the heating chamber 11 on the side of the control substrate 27 while being supported by the tubular support member 24 made of resin. Further, the humidity sensor 23 is provided in the hole 24a formed in the side wall of the support tool 24.
Insert and install. That is, both the optical sensor 22 and the humidity sensor 23 are installed on the same side as the control board 27 with respect to the heating chamber 11. By doing so, the distance between the connector of the optical sensor 22 and the connector 30 of the control board 27 and the distance between the connector of the humidity sensor 23 and the connector 31 of the control board 27 become closer,
The lead wire 28 connecting the optical sensor 22 and the control board 27 and the lead wire 29 connecting the humidity sensor 23 and the control board 27 can be shortened. Therefore, both sensors 22,23
Since there is no high-temperature part such as the exhaust port 19 on the way from the control board 27 to the control board 27, the wiring can be simplified and the cost due to the shield or the like can be reduced, and the cost can be reduced. Further, as described above, the humidity sensor 23 is supported by the resin support tool 24, and the metal side wall 13
It is designed to be thermally insulated against. Therefore,
The temperature drift characteristic of the humidity sensor 23 is improved. Further, in the present embodiment, the maximum value Vmax of the output value from the optical sensor 22 within the predetermined time T from the start of the heat treatment and the minimum value Vm within the predetermined time ΔT following the predetermined time T.
The value of the difference from in is smaller than the predetermined value β, and the difference between the initial value V ₀ of the output value from the humidity tensor 23 at the start of the heat treatment and the output value VT at the elapse of a predetermined time T from the start of the heat treatment. When the value is smaller than the predetermined value α, it is determined that the heating process is in the no-load heating state. By doing so, it is possible to detect the no-load heating state by using the optical sensor 22 and the humidity sensor 23 that have been conventionally used for performing heating control without newly providing a gravity sensor. Therefore, it is possible to inexpensively provide a safe toaster range that is free from damage due to an abnormal heating state and user's burns. In the above embodiment, the humidity sensor 23 is attached to the side wall 13 by the same support 24 as the optical sensor 22, but the present invention is not limited to this, and the humidity sensor 23 and the optical sensor 22 are separately provided. It may be attached to the side wall 13. The point is that the distance between the optical sensor 22 and the control board 27 and the distance between the humidity sensor 23 and the control board 27 are short. The configuration of the heating control circuit in the present invention is not limited to the configuration of the circuit diagram in the above embodiment. The algorithm of the no-load heating control operation in the present invention is not limited to the algorithm of the no-load heating control operation in the above embodiment.

【The invention's effect】

As is clear from the above, the heating cooker according to the first aspect of the present invention can change the amount of change in the illuminance detection signal from the light detecting means within a predetermined time and the amount of change in the humidity detection signal from the humidity detecting means within the predetermined time. Based on this, the no-load heating state detecting means detects the no-load heating state, and when the no-load heating state is detected, the heating stopping means stops the heating means. It is possible to prevent a no-load heating state without providing the sensor. Therefore, according to the present invention, it is possible to inexpensively provide a heating cooker capable of detecting a no-load heating state. Further, in the heating cooker of the second invention, the light detecting means, the humidity detecting means, the heating control means and the no-load heating detecting means in the first invention are arranged on the same side with respect to the heating chamber. Distances between the detection means and the heating control means, between the humidity detection means and the heating control means, between the light detection means and the no-load heating state detection means, and between the humidity detection means and the no-load heating state detection means Can be shortened, and the wiring related to the light detecting means and the humidity detecting means can be made simple and inexpensive. Therefore, according to the present invention, the heating cooker capable of detecting the no-load heating state can be provided at a lower cost.

[Brief description of drawings]

1 is a sectional view of an embodiment of a toaster range according to the present invention, FIG. 2 is a partial plan view of FIG. 1, and FIG. 3 is a vertical sectional view of a support 24 in FIGS. 1 and 2. FIG. 4 is a circuit diagram of a heating control circuit, FIG. 5 is a diagram showing an example of output values from an optical sensor, FIG. 6 is a diagram showing an example of output values from a humidity sensor, and FIG. 7 is no-load heating. FIG. 8 is a sectional view of a conventional toaster range, which is a flow chart of the control operation. 11 ... Heating chamber, 13 ... Side wall, 14, 15 ... Electric heater, 16 ... Oven lamp, 17 ... Magnetron, 21 ... Turntable, 22 ... Optical sensor, 23 ... Humidity sensor, 24 ... … Supporting device, 26… Operation panel, 27… Control board, 28, 29… Lead wire, 42… Microcomputer.

Claims (2)

(57) [Claims] 1. A heating means, a heating control means, a light detecting means, and a humidity detecting means, and the illuminance of the reflected light from the surface of the object to be heated detected by the light detecting means and the humidity detecting means. In a heating cooker that controls the heating means by the heating control means based on the humidity in the heating chamber, an illuminance detection signal representing the illuminance of the reflected light from the surface of the object to be heated detected by the light detecting means. Receiving a humidity detection signal representing the humidity in the heating chamber detected by the humidity detection means, based on the change amount of the illuminance detection signal within a predetermined time and the change amount of the humidity detection signal within a predetermined time. A no-load heating state detecting means for detecting a no-load heating state in which a heating process is performed in a state where there is no object to be heated in the heating chamber, and the no-load heating state detecting means. Cooker, characterized in that no-load heating condition with a heating stopping means for stopping the heating means when it is detected Te. 2. The cooking device according to claim 1, wherein the light detecting means, the humidity detecting means, the heating control means and the no-load heating state detecting means are arranged on the same side with respect to the heating chamber. And cooker.