JP2591189Y2 - Rice cooker - Google Patents

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 for electrically detecting the presence or absence of a rice cooker.

[0002]

2. Description of the Related Art Generally, a rice cooker is provided with a rice cooker detecting means for detecting the presence or absence of a rice cooker in order to prevent an accident such as an empty boil. As the rice cooker detection means according to the conventional example, for example, a sensor is provided so that a sensor can be freely inserted and removed via a coil spring from a hole provided at a central portion of the bottom surface of the inner shell for storing the rice cooker, and a rice cooker stored in the inner shell. There is a type in which the presence or absence of a rice cooker is detected by operating a microswitch disposed below the inner body by pushing down the sensor in the axial direction. Further, the sensor is formed by a pair of magnets facing each other, and the sensor is pushed down by the rice cooker housed in the inner body, so that the magnet operates a reed switch provided on the lower side of the inner body to detect the presence or absence of the rice cooker. There is something that detects

[0003]

However, any of the above-described methods is a method of mechanically detecting a signal via a movable mechanism that pushes down a sensor. Therefore, a predetermined stroke is required to operate the micro switch or the reed switch, and a movable mechanism is required.
It is difficult to reduce the size of the device, and the internal structure becomes complicated. Further, in the above-described configuration, since the sensor needs to be disposed on the bottom surface of the inner trunk, there is a problem that the degree of freedom in design is small.

In view of the above problems, an object of the present invention is to provide a small-sized rice cooker having a large degree of design freedom and a simple structure.

[0005]

Means for Solving the Problems To achieve the above object, a rice cooker according to the present invention comprises: an inner body incorporated in a rice cooker main body; and a rice cooker housed in the inner body.
The rice cooker comprises a heating means for heating the rice cooker, a first temperature detector and a second temperature detector provided with a heating element for heating, and protrudes inward from the mounting hole of the inner body to abut the rice cooker. Rice cooker detection means arranged so as to be arranged,
The difference between the detection signals of the second temperature detector is compared with a reference value. If the difference between the detection signals is larger than the reference value, it is determined that the rice cooker is not housed in the inner body, and the heating means is energized. However, when the difference between the detection signals is smaller than the reference value, it is determined that the rice cooker is housed in the inner body, and the heating means is energized.

[0006]

Therefore, according to the present invention, the difference between the detection signal and the reference value when the first and second temperature detectors of the rice cooker detecting means are in contact with the rice cooker or not. Is compared with the control means to electrically detect the presence or absence of the rice cooker.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG. As shown in FIG. 1, a rice cooker according to the present embodiment includes a rice cooker 4 in an inner body 3 disposed in a housing including a jar body 1 and a lid 2.
An induction heating coil 5 for heating the rice cooker 4 is arranged on the lower surface of the bottom of the inner shell 3, and a rice cooker detection sensor 6 is provided on a side surface near the bottom of the inner shell 3.
Is provided so as to contact the outer peripheral surface of the rice cooker 4. The induction heating coil 5 and the rice cooker detection sensor 6 are connected to a controller 7. Note that a heating plate may be provided instead of the induction heating coil 5.

As shown in FIG. 6, the rice cooker detection sensor 6 generally includes a sensor holder 10, sensor covers 17 and 18, a sensor substrate 19, and a stopper 25.
, A coil spring 29, and a sensor case 30.

The sensor holder 10 has a bulging portion 11.
Are provided with two through-holes 12 and 13 on the front surface thereof, and a pair of projections 15 and 15 projecting from the rear surface of the flange portion 14. (See FIGS. 3 and 4).

The sensor covers 17 and 18 are press-formed products made of a metal material having excellent heat conductivity such as aluminum, and the through holes 12 and 13 of the sensor holder 10 are formed.
Have a substantially hat-shaped cross-section that can be fitted to each.

The sensor substrate 19 is made of a substantially Y-shaped flexible film-shaped insulating material.
0, a thermistor 22 (negative characteristic thermistor) as a first temperature detecting unit is provided at the end of the other extended portion 21 and a thermistor 23 (negative characteristic thermistor) as a second temperature detecting unit and a heating element The resistors 24 are provided so as to be adjacent to each other. As shown in the electric circuit diagram of FIG. 2, the thermistors 22 and 23 are connected in series, and a heating resistor 24 is connected in parallel to the thermistors 22 and 23. The heating resistor 24 is located in the vicinity of the thermsitter 23. It is preferable that the thermistors 22 and 23 have the same resistance characteristics.

The retaining member 25 has a front shape that can be fitted to the bulging portion 11 of the sensor holder 10 from the rear side, and a pair of projections 26 and 27 having a substantially U-shaped cross section project from the front surface thereof. In addition, a slit 28 is provided below the projections 26 and 27 to insert the sensor substrate 19.

The coil spring 29 has a diameter that can be fitted to the pair of projections 15 of the sensor holder 10.

The sensor case 30 is a metal box housing the above-mentioned components, and includes mounting pieces 31, 31 on both sides of the front opening edge, and mounting pieces 3 on the upper edge.
Two. Each of the mounting pieces 31 and 32 is curved along the outer peripheral surface of the inner body 3.

Next, the rice cooking container detection sensor 6 is assembled as follows. That is, the sensor cover 1 is inserted into the through holes 12 and 13 of the sensor holder 10.
7 and 18, and then the extended portion 2 of the sensor substrate 19 whose lower end is inserted through the slit 28 of the stopper 25.
The ends of 0, 21 are positioned in the recesses inside the sensor covers 17, 18, respectively. And the stopper 2
5 is inserted into the inside of the bulging portion 11 of the sensor holder 10 and is locked by the locking claw 16.
At 7, the peripheral edges of the extended portions 20 and 21 of the sensor substrate 19 are pressed against and adhered to the inner surfaces of the sensor covers 17 and 18, respectively. Next, the protrusions 15 of the sensor holder 10,
After fitting the coil spring 29 to the sensor case 15 and storing it in the sensor case 30, the assembly operation is completed. However, for convenience of explanation, the stopper 2 in FIG.
5 is omitted.

As shown in FIG. 3, the sensor holder 10 is engaged with the mounting hole 8 formed in the inner body 3 and the mounting pieces 31, 32 of the sensor case 30 are integrated with the outer peripheral surface of the inner body 3. By doing so, the assembling work to the rice cooker main body 1 is completed, and the sensor holder 10 projects freely into and out of the inner trunk 3 via the coil spring 29.

Next, the operation of detecting the rice cooker 4 by the rice cooker detection sensor 6 having the above-described configuration will be described. First, when the rice cooker 4 is not stored in the inner body 3 and a power switch (not shown) is turned on by mistake, the thermistor 2
2 and 23 detect the external temperature via the sensor covers 17 and 18, respectively. However, since the thermistor 23 is heated by the heating resistor 24, the temperature is set to the thermistor 2.
2 higher than the temperature. Therefore, the voltage V ₂ of the thermistor 23 when the rice cooker 4 is not stored is lower than the voltage V _{1 of the} thermistor 22. Therefore, when the output voltages V ₁ and V _{2 of} the thermistors 22 and 23 are sent to the control unit 7, the voltage difference between them is larger than a predetermined reference value.
The control unit 7 determines that the rice cooker 4 is not stored in the inner body 3, and the control unit 7 does not energize the induction heating coil 5, thereby preventing empty heating.

Next, when the rice cooker 4 is stored in the inner body 3,
As shown in FIGS. 3 to 5, the outer peripheral surface of the rice cooker 4 comes into contact with the sensor covers 17 and 18 and pushes the sensor holder 10 against the spring force of the coil spring 29. Press in contact with 18. Then, when the lid 2 is closed and a power switch (not shown) is turned on, the heating resistor 24 heats the thermistor 23. Then, while the thermistor 22 detects the temperature of the rice cooker 4 via the sensor cover 17, the thermistor 23
As before, it is heated by the heating resistor 24, so loses heat energy to the cooking vessel 4 via the sensor cover 18, lower the temperature of the thermistor 23 than in the previous case, a high output voltage V ₂ . As a result, thermistor 2
When the output voltages V ₁ and V _{2 of 2} , 23 are sent to the control unit 7,
Since the voltage difference between the two is smaller than the predetermined reference value, the control unit 7 determines that the rice cooker 4 is housed in the inner body 3, and the control unit 7 supplies power to the induction heating coil 5 to start cooking rice. I do. The thermistor 22 used in the present embodiment not only detects the presence of the rice cooking container 4 but also functions as a normal temperature sensor, and detects, for example, the completion of rice cooking.

Next, when the rice cooker 4 is taken out of the inner shell 3 during cooking or keeping the temperature, the external temperature of the thermistor 22, which has lost the heat source, drops rapidly. On the other hand, the thermistor 23, like the thermistor 22, has a lower external temperature, but does not drop sharply unlike the thermistor 22 because it is heated by the heating resistor 24. For this reason, when the output voltages V ₁ and V _{2 of} the thermistors 22 and 23 are sent to the control unit 7, the rice cooker 4 is not stored in the inner body 3 because the voltage difference between the two is greater than a predetermined reference value. And the control unit 7 determines that the power supply to the dielectric coil 5 is stopped, thereby preventing an empty firing or the like.

[0020]

As is apparent from the above description, according to the rice cooker according to the present invention, the first and second temperature detectors of the rice cooker detecting means attached to the inner body come into contact with the rice cooker and become heated. And the control means determines the presence or absence of the rice cooker based on the difference between the obtained detection signals. For this reason, since a movable mechanism and a predetermined stroke are not required unlike the conventional example, the structure is simplified, the space can be saved, and the apparatus can be downsized. Moreover,
The rice cooker detection means does not necessarily need to be provided at the center of the bottom surface of the inner body, and can be attached to an arbitrary position on the inner body, so that the degree of freedom in design is increased.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of a rice cooker according to the present invention.

FIG. 2 is a circuit diagram of a rice cooker detection sensor attached to the inner body of the rice cooker according to the present invention.

FIG. 3 is a partial cross-sectional view of a rice cooker detection sensor attached to the inner body of the rice cooker according to the present invention.

FIG. 4 is a rear sectional view of the rice cooker detection sensor attached to the inner body of the rice cooker according to the present invention.

FIG. 5 is a schematic plan view showing a contact state of a rice cooker detection sensor attached to the rice cooker according to the present invention.

FIG. 6 is an exploded perspective view of a rice cooker detection sensor attached to the inner body of the rice cooker according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rice cooking jar main body, 3 ... Inner body, 4 ... Rice cooking container, 5 ... Induction heating coil, 6 ... Rice cooking container detection sensor, 7 ... Control part, 8 ... Mounting holes, 17, 18 ... Sensor cover, 19 ...
Sensor board, 22, 23 ... Thermistor, heating resistor ...
24.

Claims (1)

(57) [Scope of request for utility model registration] 1. An inner body incorporated in a rice cooker body, a rice cooker stored in the inner body, a heating means for heating the rice cooker, a first temperature detecting unit and a heating element for heating. A rice-cooking container detecting means, which comprises a second temperature detecting portion provided in the inner portion, protrudes inward from the mounting hole of the inner body, and is disposed so as to be able to abut on the rice-cooking container; and detection of the first and second temperature detecting portions. The difference between the signals is compared with a reference value, and if the difference between the detection signals is larger than the reference value, it is determined that the rice cooker is not housed in the inner body and the heating means is not energized, and the difference between the detection signals is smaller. A rice cooker comprising: a control unit that determines that the rice cooker is stored in the inner body when the value is smaller than the reference value, and energizes the heating unit.