JPS6124181Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the protection of a microcomputer board installed in a microcomputer-controlled rice cooker or electronic rice cooker that performs programmed rice cooking using a microcomputer.

Conventionally, a rice cooker using a microcomputer (hereinafter abbreviated as "microcomputer") has a water absorption process → a boiling process → a boiling maintenance process → a process of removing excess water → the first step, as shown in Figure 1.
Control of the steaming process → additional cooking process → second steaming process → warming process is automatically performed by a microcomputer program. Such conventional microcomputer-controlled rice cookers are equipped with a microcomputer board on which the electronic components that make up the microcomputer are installed, but the electronic components that make up the microcomputer may malfunction due to abnormal temperatures. There was a risk of damage.

The present invention was made to solve the above problem, and its features are that a microcomputer board is disposed through a predetermined gap on the outer bottom of a microcomputer-controlled rice cooker that performs programmed rice cooking; A safety temperature sensor for detecting abnormal temperature is attached, and means is provided for opening the power switch of the heating circuit when abnormal temperature is detected near the microcomputer board.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Figure 2 shows the microcomputer-controlled rice cooking system according to the present invention.
1 is a block diagram of an embodiment of a heat retention system; FIG.

In the figure, 1 is a rice cooking temperature detection lateral temperature sensor (hereinafter referred to as ``lateral sensor'') that detects the lateral temperature of the inner pot, and measures the internal temperature of the rice cooker. Reference numeral 2 denotes a center temperature sensor for detecting the cooking temperature (hereinafter referred to as "center sensor") disposed at the center of the inner bottom surface of the rice cooker, and measures the temperature near the rice cooking heater. 3 is a safety temperature sensor attached to a microcomputer board placed on the outer bottom of the rice cooker with a gap in between, and is used to protect the electronic components that make up the microcomputer from malfunctioning or being damaged due to abnormal temperatures. 4 is a power failure detection circuit arranged in the microcomputer board; 5
is the inner pot detection sensor installed on the side of the rice cooker.
6 is a rice cooking switch, 7 is a deep cooking switch, 8 is an abnormal temperature detection circuit 8 attached to the microcomputer board, 9 is a microcomputer, and 10 is a rice cooking display that shows that a series of rice cooking processes are in operation. be. This rice cooking display section 10 is, for example, a slow-moving display that indicates that the water absorption process is in operation.
ELD, flash display to indicate that the boiling process and boiling maintenance process are in operation.
It is composed of a plurality of display lamps for each process, such as an ELD and a first unevenness display ELD that indicates that the first unevenness process is in operation. In addition, the rice cooking display section 10
may be one indicator lamp that lights up when any of the above steps is in operation. Reference numeral 11 denotes a heat retention display section that displays that a series of heat retention processes are in operation, a deep additional cooking display ELD that indicates that a deep additional cooking process is in operation, and a deep additional cooking display ELD that indicates that a second uneven cooking process is in operation. 2nd irregularity display ELD, heat retention display to indicate that the long-term heat retention process is in operation
It consists of multiple indicator lamps that indicate that each process such as ELD is in operation.

Incidentally, the heat retention display section 11 may be a single indicator lamp that lights up when any of the above-mentioned steps is in operation. Reference numeral 12 denotes a detection buzzer, and the tone color and the sounding period or the sounding interval of the notification sound can be changed as necessary. 13
is a heating circuit for the rice cooking section and the warming section.

FIG. 3 is a diagram showing a specific example of the heating circuit 13 of the rice cooking section and warming section shown in FIG. 2, where S is a commercial AC power supply, F is a temperature fuse, SW is a power switch, and MH is a rice cooking heater. , TRIAC is a semiconductor switching element for alternating current control such as TRIAC, TRS
is a thermal reed switch, M1 is a main horizontal heater, M2 is a sub horizontal heater, and MS is a lid heater.

FIG. 4 is a diagram showing an embodiment of the mounting position of the microcomputer board and the security temperature sensor 3 of the present invention, and the rice cooking heater MH and the center sensor 2 are arranged very close to each other. , the microcomputer board 14 has a gap 16 on the outer bottom surface 15 of the rice cooker.
The microcomputer board 14 is mounted in such a way that the temperature around the microcomputer board 14 does not rise abnormally due to air convection.

Also, abnormal temperature rise due to high power (1100W) at the initial stage of rice cooking can be prevented by the abnormal temperature detection circuit using the center sensor 2, but even if the temperature is normal, if the heating time becomes long, be careful of the effect on the microcomputer board 14. Therefore, the microcomputer board 14 is provided with a security temperature sensor 3 and an abnormal temperature detection circuit.

FIG. 5 is a diagram showing the configuration of an embodiment of an abnormal temperature detection circuit for protecting electronic components constituting the microcomputer of the present invention.

In the figure, 3A is a comparator, and its "-"
A security temperature sensor 3 is connected to the input terminal,
The "+" input terminal is connected to the output of a reference voltage setting device 3B corresponding to dangerous abnormal temperatures. The reference voltage corresponding to the dangerous abnormal temperature is set, for example, to a value at which the comparator 3A operates when the output of the security temperature sensor 3 reaches 75° C. or higher.

When there is an output from the comparator 3A, the output is inputted to the microcomputer 9 via the OR circuit to open the power switch SW of the heating circuit 13 for cooking and keeping warm, and at the same time the notification buzzer 10 is activated until it is reset. It keeps ringing. In the figure, 4A is a comparator of the power failure detection circuit, and 4B is a reference voltage setter.

In the present invention, it goes without saying that the abnormal temperature detection means is not limited to the above-mentioned embodiments, and may be any known means.

As explained above, according to the present invention, the heat retention temperature sensor constantly monitors the temperature near the microcomputer board, and when an abnormal temperature occurs, the abnormal temperature detection circuit detects it and opens the power switch of the heating circuit. This makes it possible to prevent malfunctions or damage to electronic components constituting the microcomputer due to abnormal temperatures.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the conventional rice cooking and warming process.
Fig. 2 is a block diagram of an embodiment of the microcomputer-controlled rice cooking/warming system according to the present invention; Figure 4 is a diagram showing an embodiment of the mounting position of the microcomputer board and safety temperature sensor 3 of the present invention, and Figure 5 is an example of an implementation of the abnormal temperature detection circuit for protecting the electronic components that constitute the microcomputer of the present invention. FIG. 2 is a diagram showing an example configuration. 1... Side temperature sensor, 2... Center temperature sensor, 3... Security temperature sensor, 4... Power outage detection circuit, 3A, 4A... Comparator, 3B, 4
B... Reference voltage setting device, 5... Inner pot detection sensor, 6... Rice cooking switch, 7... Deep cooking switch, 8... Abnormal temperature detection circuit, 9... Microcomputer,
10... Rice cooking display section, 11... Heat retention display section, 12
...Detection buzzer, 13...Heating circuit for rice cooking section and heat retention section, 14...Microcomputer board, 15...Outer bottom part of rice cooker, 16...Gap, 17...OR circuit.

Claims (1)

[Scope of utility model registration request] A microcomputer board is disposed at a predetermined position of a microcomputer-controlled rice cooker that performs programmed rice cooking, and a safety temperature sensor for detecting abnormal temperature is provided on the microcomputer board, and an abnormal temperature is detected near the microcomputer board. 1. A microcomputer-controlled rice cooker characterized by comprising means for opening a power switch of a heating circuit when the heating circuit is turned on.