JPH04325122A - Rice cooker - Google Patents

Abstract

PURPOSE:To suppress a dewing generated on the inside surface of a cover body at the time of rice cooking by a simple circuit configuration. CONSTITUTION:At the time of rice cooking, a rice cooking heater 36 is energized and deenergized by opening and closing a relay 74, and also, a barrel heater 37 and a cover heater 38 are energized by turning on a triode AC switch 75. At the time of warming, the rice cooking heater 36 is always deenergized by opening the relay 74, and also, the barrel heater 37 and the cover heater 38 is energized and deenergized by turning on and off the triode AC switch 75. In the course of rice cooling, the cover heater 38 heats the cover body, and dewing on its inside surface is prevented. Since the rice cooking heater 36 is not energized at the time of warming, it is unnecessary to add one triode AC switch for the circuit configuration, and the circuit configuration becomes simple.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker, and more particularly to a rice cooker having a structure for suppressing dew condensation generated on the inner surface of a lid during cooking.

0002

[Prior Art] A conventional rice cooker includes a container that is removably housed in a main body, a lid that opens and closes an opening on the top of the main body, and a lid that is located below the container. a rice-cooking heater provided on the container, a body heater for side heat retention provided on the main body of the container and located on the upper side of the container, and a lid provided on the lid body located above the container. and a lid heater for keeping heat in the rice cooker, and when cooking rice, when a triac (described later) is in an off state, the input of the rice cooking heater is controlled to be energized or de-energized via a relay based on the output of a temperature sensor that detects the temperature of the container; When keeping warm, with the relay in the open state, the body,
The series circuit of the lid heater and the rice cooking heater is configured to be energized/disconnected via a triac. However, this rice cooker does not have a condensation suppressing structure and the rice cooking operation is performed by energizing only the rice cooking heater located below the container, so the temperature of the lid body may become lower than the rice temperature during the uneven operation during cooking. There is a problem in that dew condensation occurs on the inner surface of the lid due to this. In order to solve this problem, some rice cookers are conventionally known that are configured to heat the lid and suppress the occurrence of condensation by energizing at least the lid heater together with the rice cooking heater during rice cooking. Here, an example of the circuit configuration of a conventional rice cooker of this type will be explained with reference to FIG. A transformer 2 is connected between both poles of a 100V AC power supply 1, and a constant voltage circuit 3 connected to the transformer 2 is connected to a microcomputer 4, which is supplied with DC power. Further, a series circuit of a contact 5A of a relay 5 and a rice cooking heater 6 is connected between the poles of the AC power supply 1, and a series circuit of a parallel circuit of a body heater 7 and a lid heater 8 and a first triac 9 is connected. Connected. Furthermore, a second triac 10 is connected between the connection point of the contact 5A and the rice cooking heater 6 and the connection point of the shell, lid heaters 7 and 8, and the first triac 9. The coil 5B of the relay 5 is connected to the relay drive circuit 11.
The first triac 9 is connected to the microcomputer 4 via a first triac drive circuit 12, and the second triac 10 is connected to the microcomputer 4 via a first triac drive circuit 12. It is connected to the microcomputer 4 via a drive circuit 13. Furthermore, a temperature sensor 14 consisting of a thermistor is also connected to this microcomputer 4. And when cooking rice, use a second Triac 10
is always off, and based on the output of the temperature sensor 14,
The relay 5 is controlled to open and close, the rice cooking heater 6 is controlled to be energized, and the first triac 9 is controlled to be turned on and off, and the shell and lid heaters 7 and 8 are controlled to be energized and disconnected. On the other hand, when keeping warm, the relay 5 is always closed, the first triac 9 is always off, and the second triac 10 is controlled on and off, so that the rice cooking heater 6 is connected in series with the body and lid heaters 7 and 8. The circuit is energized and de-energized. Further, FIG. 8 shows another conventional example. In this conventional example, in addition to the rice cooker, body, and lid heaters 6, 7, and 8 similar to the previous conventional example, another lid heater 16 is provided on the lid body, and this lid heater 16 and a first triac 9 are provided. A series circuit with is connected between both poles of the AC power supply 1. The electrical connections among the relay 5, rice cooking heater 6, second triac 10, shell, and lid heaters 7 and 8 are the same as in the prior art example except for the connection position of the triac 10. During rice cooking, the second triac 10 is always off, and based on the output of the temperature sensor 14, the relay 5 is controlled to open and close, the rice cooking heater 6 is controlled to be energized, and the first triac 9 is controlled to be on and off. Then, the lid heater 16 is controlled to be turned on and off. On the other hand, when keeping warm, the relay 5 is always closed, and the first triac 9 is always off. The circuit is energized and de-energized.

In any of the above conventional examples, the amount of dew condensation on the inner surface of the lid is reduced by heating the lid with the lid heaters 8 and 16 during rice cooking. However, in both of the conventional examples, the relay 5 and the relay drive circuit 11, the first triac 9 and the first triac drive circuit 12, and the second The triac 10 and the second triac drive circuit 13 are used, and one more triac is required compared to the one that does not heat the lid during rice cooking and does not have a condensation suppressing structure. Since a circuit is also required, there are problems in that the circuit configuration becomes complicated, the assembly is difficult, the circuit board becomes large, the control becomes complicated, and as a result, the reliability decreases. The reason why three energization/disconnection control means are necessary is to perform heating control by forming a series circuit between the rice cooking heater 6, the shell, and the lid heaters 7 and 8 during warming. The reason why three energization/disconnection control means are necessary will be explained in more detail as follows. Condensation is especially noticeable on rice cooker heater 6.
To prevent condensation, it is necessary to control the rice cooking heater 6 and the body and lid heaters 7 and 8 separately during cooking. Control means are required. Furthermore, if the rice cooking heater 6 is to be energized during warming, the input must be lower than that during rice cooking, so it is necessary to add at least one energization/disconnection control means.

0004

[Problems to be Solved by the Invention] As mentioned above, in the conventional rice cooker that uses a lid heater to heat the lid body even when cooking rice,
Because the rice cooking heater was used to heat the rice even when keeping it warm,
There were problems in that the circuit configuration became complicated, the ease of assembly deteriorated, and the reliability decreased. The present invention has been made in consideration of the above circumstances, and is capable of suppressing dew condensation on the inner surface of the lid body during rice cooking, as well as simplifying the circuit configuration.
The purpose is to provide a highly reliable rice cooker that can be easily assembled.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the rice cooker of the present invention includes a container 26 that is removably housed in the main body 21, and a lid that opens and closes the top opening of the main body 21. a rice cooking heater 36 located below the container 26 and provided in the container main body 21; and a side warming heater 37 located on the side of the container 26 and provided in the container main body 21. , a lid heat retention heater 38 located above the container 26 and provided on the lid 27;
a temperature sensor 39 for detecting the temperature of the temperature sensor 39; It is equipped with a heat retention control means 63 that controls the inputs of the lid and side heat retention heaters 38 and 37 based on the output.

[0006]

[Function] During rice cooking, in the rice cooker of the present invention, the inputs of the rice cooking heater 36, the lid, and the side heat retaining heaters 38, 37 are controlled based on the output of the temperature sensor 39 that detects the temperature of the container 26. Heat retention heater 37
The container 26 is heated from below and from the sides, and the lid 27 is heated by the lid heater 38. By heating the lid body 27 in this way,
During rice cooking, condensation on the inner surface of the lid 27 is suppressed. On the other hand, when keeping warm, the lid and
The inputs of the side heat retention heaters 38 and 37 are controlled, and the container 26 is heated by the side heat retention heater 37.
The lid 27 is heated by the lid heat retaining heater 38.

[0007]

[Example] The following is an example of the rice cooker of the present invention.
This will be explained with reference to FIG. FIG. 4 is a sectional view of the rice cooker. In the figure, reference numeral 21 denotes a container main body with an open top surface, and this container main body 21 consists of an inner case 22 and an outer case 23.
A heat insulating material 24 is provided between the three. Inner case 22
An aluminum reflective plate 25 is provided at the lowest part of the interior. The inner case 2 is located on this reflector plate 25.
A container 26 with an open top is removably housed in the container 2 . 27 is a lid body, and this lid body 27 includes an outer lid 28 that opens and closes the top opening of the main body 21, a lid frame 29 provided on the lower side of this outer lid 28, and a lower side of this lid frame 29. The container 26 is provided with an inner lid 30 that opens and closes the top opening of the container 26, and a heat insulating material 31 is provided between the outer lid 28 and the inner lid 30. The lid body 27 is rotatably supported on the container body 21 by a hinge 32 located on the right side in the drawing, and a spring 33 provided at the hinge 32 portion.
is always biased in the open direction. One device body 21
A clamp 34 that engages with and disengages from the lid body 27 and holds the lid body 27 in a closed state against the bias of a spring 33 is pivotally attached to the left side in the figure. Note that the lid body 27 is provided with a steam port 35 that communicates the inside of the container 24 with the outside. A rice cooking heater 36 is provided below the container 26 and above the reflector 25. Inner case 22
A body heater 37, which is a side heat-retaining heater, is installed on the outer surface around the
is provided. This body heater 37 is located on the side of the container 26, and is disposed over the range from the top to the bottom of the container 26. Furthermore, a lid heater 38 serving as a lid heat retention heater is provided on the inner lid 30 and located above the container 26. The rice cooking heater 36 that heats the container 26 from below is energized at 650W, and the body heater 37 that heats the container 26 from the side is energized at 47W, and is a lid heater that mainly heats the inner lid 30, that is, the inner surface of the lid body 27. 38 is energized at 16W. Further, a temperature sensor 39 made of a thermistor or the like and detecting the temperature of the container 26 is provided at the lowest part of the inner case 12 so as to be movable up and down. This temperature sensor 39 is always urged upward by a coil spring 40 so as to come into pressure contact with the lower surface of the container 26. At the same time, a container switch 41 is provided at the bottom of the inner case 12 to mechanically interlock with the temperature sensor 39 and detect that the container 26 is attached. Further, a cord reel 44 is provided on the lower surface of the outer case 23 for rotating a power cord 43 having a plug 42 connected to its tip. Furthermore, a circuit board 45 is provided on the side of the container body 21, located between the inner case 22 and the outer case 23, and a power supply unit 46 is mounted on this circuit board 45. An operating unit 47 is provided near the power supply unit 46 at the upper part of the outer surface of the outer case 23. Furthermore, a fuse 4 is installed at the top of the outer surface of the inner case 22.
8 is provided. FIG. 2 is a block diagram showing the electrical configuration. In the figure, 51 is a microcomputer, and this microcomputer 51 includes a CPU 52,
It has a clock means 53, a memory 54, an input circuit 55, and an output circuit 56. The input circuit 55 is connected to an operating means 57 such as a push button switch provided on the operating unit 47, and the temperature sensor 39 is also connected via an A/D converter 58. The output circuit 56 also includes the heaters 36, 37, 38.
are connected to each other via a heater drive means 59, and a display means 60 consisting of a light emitting diode, a liquid crystal display, etc. provided in the operation unit 47 is connected to the display drive means 6.
1. As shown in FIG. 1, the microcomputer 51 has, as software functions, a rice cooking control means 62 that controls the inputs of the rice cooking heater 36 and the body and lid heaters 37 and 38 based on the output signal of the temperature sensor 39, and a temperature sensor. It has a heat retention control means 63 for controlling the inputs of the shell and lid heaters 37 and 38 based on the output signal of the heater 39. FIG. 3 is a circuit diagram of the power supply section and heater drive section. In the same figure, 71 is 10
A transformer 72 is connected to this AC power source 71, which is a 0V AC power source, and this transformer 72 is connected to the microcomputer 51 via a constant voltage circuit 73. In this way, this microcomputer 51 is supplied with DC power. Additionally, a rice cooking heater 36 is connected between both poles of the AC power supply 71.
A series circuit of the contact point 74A of the relay 74 is connected, and a parallel circuit of the body heater 37 and the lid heater 38 is connected to a series circuit of the triac 75. The coil 74B of the relay 74 is the relay drive circuit 7.
The gate of the triac 75 is connected to the microcomputer 51 via a triac drive circuit 77. Therefore, only when the coil 74B is energized by the output signal from the microcomputer 51 via the relay drive circuit 76, the contact 74A is closed and the rice cooking heater 36 is energized. Only when the triac 75 is turned on by being triggered by the triac 77, the body heater 37 and the lid heater 38 are energized.

Next, the operation of the above structure will be explained. First, the outline of the operation will be explained with reference to the flowchart of FIG. For example, rice cooking is started when the user operates the rice cooking switch on the operation unit 47, and a deep cooking operation and a regular rice cooking operation are performed (step 1).
. Then, the temperature detected by the temperature sensor 39 is 12
It is determined whether the temperature is 0°C or higher (step 2),
If the temperature is less than 120°C, return to step 1. That is, the main rice cooking operation continues until the temperature detected by the temperature sensor 39 reaches 120°C. When the temperature detected by the temperature sensor 39 reaches 120° C. or higher, the uneven operation is performed (step 3). 15 from the start of uneven movement
It is determined whether the minute has elapsed (step 4), and if the time has not elapsed, the process returns to step 3. That is, the uneven rice cooking operation is performed for 15 minutes after the end of the main rice cooking operation. After 15 minutes have elapsed, the rice cooking ends and the warming operation starts (step 5). In the soaking operation, main rice cooking operation, and uneven rice cooking operation, the relay 74 is controlled to open and close, and the rice cooking heater 36 is controlled to be energized, but the triac 75 is always on, and the body and lid heaters 37 and 38 are always energized. ing. On the other hand, during the heat retention operation, the triac 75 is controlled on and off to control the body and lid heaters 37 and 38.
is controlled to be on/off, but the relay 74 is always open and the rice cooking heater 36 is always off. To explain in more detail the heating control during the heat retention operation, if the temperature detected by the temperature sensor 39 is 71°C or higher, the triac 75 is turned off, the body and lid heaters 37 and 38 are cut off, and the 7
If the temperature is less than 1° C., the triac 75 is turned on and the body and lid heaters 37 and 38 are energized. Here, each heater 36,
The timing of energization/disconnection of 37 and 38 and the temporal change in temperature detected by the temperature sensor 39 will be explained in detail with reference to the graph of FIG. In the figure, the upper graph shows the temperature change detected by the temperature sensor 39, and the lower two graphs show the temperature changes for each heater 36, 37.
, 38 are shown. When rice cooking starts, the rice cooking heater 36 is turned on and off at a preset timing, and first, the rice is boiled. After a predetermined period of time has elapsed from the start of rice cooking, the main rice cooking operation starts, the rice cooking heater 36 is continuously energized, and the temperature increases. Further, after a predetermined period of time has elapsed since the boiling state is detected after the continuous energization of the rice cooking heater 36 starts, the rice cooking heater 36 is energized intermittently, and the temperature rise becomes slower. When the temperature reaches 120° C., the rice cooker shifts to uneven operation, and during this uneven operation, the rice cooking heater 36 is temporarily energized for a short time. Furthermore, when 15 minutes have passed since the start of steaming, the rice cooking operation ends and the rice keeping operation starts. During this warming operation, the rice cooking heater 36 is always cut off. On the other hand, the barrel and lid heaters 37 and 38 are continuously energized from the start of rice cooking until the end of cooking, but they are temporarily cut off when keeping warm, and then are energized intermittently so that the temperature detected by the temperature sensor 39 is maintained at 71°C. do.

According to the configuration of the above-mentioned embodiment, by heating the inner surface of the lid body 27 especially by the lid heater 38 during rice cooking, dew condensation occurring on the inner surface of the lid body 27 can be suppressed. Also, when cooking rice, the rice cooking heater 36, the body, the lid heater 37,
38 are controlled separately, but since the configuration is such that only the body and lid heaters 37 and 38 are used to heat the heaters 36, 37, and 38 during heat retention, the power supply/disconnection control means for the heaters 36, 37, and 38 is controlled by one relay 74 and one relay drive. Only the circuit 76, one triac 75, and one triac drive circuit 77 are required. In this way, the circuit configuration is as simple as that of a conventional rice cooker that does not use a lid heater to heat rice during cooking, and there are no additional parts for heating control compared to this conventional rice cooker, so it is easy to assemble and the circuit The substrate 45 does not become large, the control does not become complicated, and a decrease in reliability can be prevented. By the way, in this embodiment, the container 26 is
Since there is no heating by the lower rice cooking heater 36, if the body heater 37 were arranged only above the vertical center of the container 26 as in the past, the bottom of the container 26 would be insufficiently heated during keeping warm. Therefore, there is a possibility that the temperature of the rice in the container 26 may become uneven. However, in this embodiment, since the body heater 37 is also disposed at a position corresponding to the lower part of the container 26, insufficient heating of the bottom of the container 26 during heat retention is prevented, and the container 26 is heated similarly to the conventional rice cooker.
You can heat the rice evenly and evenly and get delicious rice.

[0010] The present invention is not limited to the above-mentioned embodiments, and various modifications are possible. For example, in the embodiment described above, the body and lid heaters 37 and 38 are constantly energized during rice cooking, but in order to obtain an appropriate amount of heating, the body and lid heaters 37 and 38 may be appropriately turned off during rice cooking.

[0011]

[Effects of the Invention] According to the present invention, by heating the lid body with the lid heat retention heater when cooking rice, dew condensation that forms on the inner surface of the lid body can be suppressed, and when keeping rice warm, heating is performed only by the lid and side heat retention heaters. By doing this, the circuit configuration for controlling the rice cooking heater, the lid, and the side heat retaining heater can be simplified, and the ease of assembly and reliability can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a rice cooker of the present invention.

FIG. 2 is a block diagram showing the electrical configuration of the same as above.

FIG. 3 is a circuit diagram of the same as above.

FIG. 4 is an overall sectional view of the same as above.

FIG. 5 is a flowchart showing an outline of the same operation as above.

FIG. 6 is a graph showing timing of energization/disconnection of the same heater and temperature changes.

FIG. 7 is a circuit diagram showing an example of a conventional rice cooker.

FIG. 8 is a circuit diagram showing another example of a conventional rice cooker.

[Explanation of symbols]

21 Main body 26 Container 27 Lid 36 Rice cooking heater 37 Body heater (side heat retention heater) 38 Lid heater (lid heat retention heater) 62 Rice cooking control means 63 Heat retention control means

Claims (1)

[Claims] 1. A container that is removably inserted into a container body, a lid that opens and closes a top opening of the container body, and a rice cooking heater that is located below the container and is provided in the container body. , a side heat-retaining heater located on the side of the container and provided on the container body; a lid heat-retaining heater located above the container and provided on the lid body; and detecting the temperature of the container. a temperature sensor for controlling the temperature sensor; a rice cooking control means for controlling the inputs of the rice cooking heater, the lid, and the side heat-retaining heater based on the output of the temperature sensor; A rice cooker characterized by comprising a heat retention control means for controlling the heat retention.