JPH0826997B2 - Heating cooker - Google Patents

Description

TECHNICAL FIELD The present invention relates to automatic time cooking of a heating cooker that heats using a heating heat source such as an electric oven or an oven toaster.

2. Description of the Related Art In a toaster oven or the like that puts an object to be heated such as bread in the heating chamber and energizes the heaters above and below the heating chamber, simply set the heating time in the oven toaster etc. to control the heating time Alternatively, temperature control is performed to shut off the power supply to the heater when the temperature of the bimetal type switch or the temperature inside the heating chamber reaches a predetermined temperature by using a temperature sensing element such as a thermistor.

However, in the time control according to the conventional method as described above, since the temperature in the heating chamber changes during repeated use, it is necessary to adjust the optimum heating time after each use. However, the heating can be finished when the temperature in the heating chamber is substantially constant, but a temperature sensitive element such as a bimetal type switch or thermistor for measuring the temperature is required. Therefore, there is a drawback that the cost becomes high. or,
When the temperature sensitive element is used, the cost becomes high and the temperature of the temperature sensitive element needs to be adjusted, which requires time and effort for manufacturing. Further, since the ambient temperature of the food placed in the heating chamber causes a delay time due to the heat capacity of the heater and the heating chamber, there is a problem that some correction is necessary.

Means for Solving the Problems In the present invention, therefore, in order to solve the above problems, a heater serving as a heating heat source, a heating chamber heated by the heater, a function selection switch for selecting a heating operation of the heater, and the function selection switch. Drive means for starting and ending the operation of the heater by the, a storage unit for storing the reference heating time for each heating function, a time measuring means for counting the reference pulse to measure the time, and in advance during the heating operation and the heating stop. Automatically having a calculation means for increasing or decreasing the heating time according to a predetermined calculation formula, and stopping the heating operation of the heater according to the increase or decrease of the reference heating time and the heating time obtained by the calculation means when the heating operation is started. It has a cooking means.

Action Since the temperature in the heating chamber is estimated by replacing it with the increase or decrease of the heating time, the temperature control using the temperature sensitive element can be performed in almost the same manner. In addition, the temperature of the heating chamber (due to residual heat) is always estimated based on the time when electricity was turned on and the time when it was stopped, the reference heating time is corrected, and the heating time when heating is performed again is determined. It can be cooked by heating.

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

FIG. 1 is a sectional view of an essential part of an embodiment of an oven toaster using the present invention.

In FIG. 1, a heating chamber 2 for heating and cooking an object to be heated is provided in a main body 1, and an upper heater 3 having a coil-shaped heating element inserted in a pipe is provided above the heating chamber 2.

On the bottom surface of the heating chamber 2 is provided a grill 4 on which food is placed, and on this grill 4, a bread 5 to be heated is placed. Reference numeral 6 denotes a planar heater which is attached in close contact with the bottom surface of the heating chamber 2 and is a lower heater.

With these configurations, the bread 5 placed in the heating chamber 2 can be heated and cooked by using the upper heater 3 and the lower heater 6.

FIG. 2 shows an embodiment of the electronic circuit and control circuit of the oven toaster of the embodiment of the present invention shown in FIG. In the figure, 8 is a door switch that opens and closes in conjunction with the door of the heating chamber of the outlets 9 and 10 of the power supply for the goods.

The switch 10 is input to the microcomputer 11. Reference numerals 3 and 6 are the above-mentioned upper heater and lower heater, respectively. 12 to 15 are relays whose contacts are opened and closed by the control circuit. Reference numeral 16 is a low-voltage power supply that supplies operating power for the control circuit and the relays 12 to 15.

The microcomputer 11 stores a program for executing an embodiment of a control sequence according to the present invention, which will be described later. Further, a clock signal 17 for generating a timing signal synchronized with a commercial power supply is input as an input of the microcomputer 11. In addition, the function selection switch 18 for inputting the type of heating function, for example, "toaster", "pizza", "fried food", "mochi", etc., and the setting means 19 comprising an operation switch for instructing start and forced stop of heating are connected. There is. Reference numeral 20 is a display means for displaying the type of heating function, heating time or remaining heating time that has been set. Reference numeral 21 is a driving IC for driving the relays 12 to 15.

FIG. 3 is a block diagram of a control unit according to one embodiment of the present invention. This is the microcomputer of Fig. 2.
It is configured as a program in 13.

First, the setting unit 22 gives the operation command unit 23 corresponding to the heating function set by the setting means, and the operation command unit 23 starts the heating operation by the door signal, the setting contents, the heating start input, the heating time storage unit 24, etc. Instruct to suspend, end, etc. The time measuring means 25 receives a clock pulse generated from the reference pulse generating section 26 by the clock signal shown in FIG. 2 as an input and measures a fixed time, for example, 1 second or 1 minute, and the time is calculated for each block. Give a signal. The heating time calculation means 27 is a means for constantly calculating the optimum heating time when cooking again according to the procedure described in detail later, and is composed of a program and a memory in the microcomputer. The drive unit 28 receives the output from the operation command unit 23 and drives a heat source such as a heater.

An embodiment of heating and cooking according to the present invention will be described with reference to FIG. 4 in order to explain the operation of each block in detail.

It is a case where the heater is heated by a heater that burns the object to be heated by the radiant heat of a heat source such as an oven toaster, and the kind of the object to be heated, for example, when two heaters are not used yet and the room temperature is heated. If the output is a constant value (for example, 900 W) and the heat capacity determined by the size and material of the heating chamber is constant, the reference heating time for each heating function can be almost determined. However, there are two problems here. One is when there is residual heat in the heating chamber that was taken the first time and the second time,
This means that it is necessary to change the heating time depending on the amount of heat supplied with respect to the time when the previous heater is operated when the new cooking is started and the amount of heat radiated by the rest time. Another problem is when the output of the heater changes depending on the heating function. For example, "toaster" and "mochi" are baked with the upper and lower heaters as strong output to shorten the heating time and keep the internal moisture, but for "pizza", the lower heater is strong output and the upper heater is weak output. It is necessary to lightly bake the bottom of the
In the case of "fly", the output of each heater changes when the upper and lower heaters are made to have a weak output and they are slowly baked so that heat can be sufficiently transmitted to the inside. Therefore, the amount of heat supplied and the amount of heat radiated also change depending on the heating function, and it is necessary to change the heating time. The change in the heating time at Fig. 4 of heating the two aforementioned bread upper and lower heaters strong output on the x-axis, the cumulative heating time t _a to y-axis, the optimum heating time t _y z
For the axis, the stop time t _b is represented as three-dimensional coordinates. When the heater is not used yet and is heated from room temperature, the heater output is a constant value (strong output in this case), and if the size and material of the heating chamber are constant, the time required for cooking is coordinated. Since the origin is t _y0 above, the optimum heating time t _y here can be easily obtained by experiment. Similarly, the cumulative heating time t _a1 The optimum heating time t _y1 when the heating is repeated immediately after the operation is repeated exponentially decreases from the optimum heating time t _y0 when the equipment is cold, and the temperature _inside the heating chamber rises due to the heater. However, it stabilizes when it reaches an equilibrium state. In addition, the optimum heating time t _y2 when the equipment is stopped for only the accumulated heating time t _a1 and stopped for the stop time t _b1 and then heated again is the same as the optimum heating time t _y1 when restarting immediately afterwards. Exponentially increasing, and when the heating chamber returns to the cold state, the same optimum heating time as the origin
It becomes t _y0 . FIG. 5 (a) shows x-y coordinates on the origin of FIG. 4, which is a function of the optimum heating time t _{y with} respect to the cumulative heating time t _a , and is approximately t _y1 = t _y0 −At _a (t _y1 ≧ t _s ) (A is a predetermined constant, t _s is the shortest heating time) Similarly, FIG. 5 (b) shows (a) − ( B)-
(C)-(d)-(e)-(f) plane is a function of the optimum heating time t _{y with} respect to the stop time t _b , and is approximately t _y2 = t _y1 −Bt _a ( It can be obtained from t _y2 ≤ t _y0 ). (B is a predetermined constant) the optimum heating time when the heater in this manner was heated again at a optimum heating time of the cooking t _y0 and stop time after the cumulative heating time t _a t _b when during cold t _y2 can be obtained by using the above two functions. However cumulative heating time t _a when heated further again is not a simple (t _a + t _y2). This is because the heating chamber gradually cools during the stop time t _b , so it is necessary to find a new optimum heating time.

Therefore, the optimum heating time (t _y2 ) found when heating again
_Is replaced with t _y1 in Fig. 5 (a) and the cumulative heating time (t _a ) is inversely calculated from the value of t _y2 , and the heating and stopping times up to that point are taken as the cumulative heating time (t _a ′). Remember. In this case, the inverse operation is t _a ′ = (t _y0 −t _y2 ) / A, and the cumulative heating time t _a in the case of reheating again is
It becomes t _a ′ + t _y2 , and the optimum heating time t _y for the nth time can be calculated by the cumulative heating time t _a ′ and the stop time t _b .

Further, in order to correspond to the output of the heater vary with the heating function may be able to have a respectively different values by each cooking function constants A and t _s a function of the optimum heating time t _y with respect to the cumulative heating time t _a as described above. In this case, the optimum heating time t _y0 in the cold state is different from each other, but A and t _y0 can be experimentally determined.

Optimal heating for most affected foregoing downtime by opening and closing state of the door is different degree of heating chamber heat is dissipated to the compartment out depending is closed or the door of the heating chamber is open as a large factor t _b respect downtime t _b The constant B of the function at time t _y may be different.

Furthermore, the optimum heating time t _y calculated by the above-mentioned conditions
It is also possible to adopt a finishing adjustment function (constant times t _y ) in which the degree of heating is appropriately changed according to the user's preference, with the standard as.

Effects of the Invention With the above configuration, the present application can obtain the following effects.

(1) Since the amount of heat remaining in the heating chamber due to past cooking is always estimated and the heating time is calculated again, it is possible to expect a regular and constant finished state.

(2) Since a temperature sensitive element such as a thermistor is not used and only time measurement and a simple arithmetic expression are required, the structure is simple and the cost can be reduced.

(3) Since the calculation formula for calculating the optimum heating time is changed by the heating and cooking function, more accurate control can be performed.

(4) Since the calculation formula for calculating the optimum heating time for cooking again is changed depending on the opening / closing state of the door when the heating cooker is stopped, more detailed control can be performed.

(5) Since it is not necessary to set the heating time each time only by selecting the heating and cooking function, the operation is easy and the usability is good.

[Brief description of drawings]

FIG. 1 is a sectional view of a main portion of an oven toaster according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a control unit of an oven toaster according to an embodiment of the present invention, and FIG. 3 is a block of a control unit of the oven toaster. FIGS. 4 and 5 are explanatory views showing the time calculated by the calculating means of the optimum heating time of the oven toaster, and FIGS. 5 (a) and 5 (b) are explanatory views of the calculating means. 1 ... Main body, 2 ... Heating chamber, 3 ... Upper heater, 6 ...
Lower heater, 9,10 ... Door switch, 11 ... Microcomputer, 22 ... Setting section, 23 ... Operation command section, 24 ...
… Heating time storage unit, 25 …… Time measuring means, 26 …… Reference pulse generating unit, 27 …… Heating time calculation unit, t _y0 …… Cold optimum heating time, t _a …… Cumulative heating time, t _b … …Stop time.

Claims (4)

[Claims] 1. A heating chamber for accommodating an object to be heated in a main body, a heat source for heating an object to be heated in the heating chamber, a function selection switch for selecting a heating operation of the heat source, and a signal from the function selection switch. The operation command section that starts and ends the heating operation by the memory, the storage section that stores the reference heating time that is preset for each function, the time measuring means that counts the reference pulse and measures the time, and the preset during the heating operation. It has a calculation means for reducing the heating time at regular time intervals according to the calculation formula and a calculation means for increasing the heating time at constant time intervals according to a predetermined calculation formula while the heating is stopped. A heating cooker, characterized in that the heating operation of the heat source is stopped according to the increase and decrease of the heating time and the heating time obtained by the calculating means. 2. The heating cooker according to claim 1, further comprising inverse calculation means for replacing the increase / decrease value of the heating time obtained by the calculation means with the cumulative heating time. 3. The heating cooker according to claim 1, wherein the output of the heat source is changed by the function selection switch, and the calculation formula for reducing the heating time at regular time intervals during heating is different. 4. An arithmetic expression for increasing a heating time at a constant time is provided in accordance with the open / closed state of the door, with a switch for detecting the open / closed state of the door of the heating chamber provided. Item 2. A heating cooker according to item 1.