JPH1176048A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent starch from overflowing during rice cooking. SOLUTION: This rice cooker is provided with a heating means (heating coil 3) for a cooking pot 2, controller 8 for controlling the electrifying state of the heating means 3, steam cylinder 9 for discharging steam in the rice cooking pot 2, and overflow sensor 12 arranged on the steam cylinder 9. Then, the outer shell of the overflow sensor 12 is covered with synthetic resin and between metallic polar panels, a PTC thermistor is held.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a rice cooker.

[0002]

2. Description of the Related Art Conventionally, in a rice cooker of this kind, a rice cooker main body 21 has a rice cooker 22 therein, and a heating coil 23 for heating the rice cooker 22 by electromagnetic induction and a heating coil 23 thereunder. A power supply device 24 for driving and a temperature sensor 25 for detecting the temperature of the rice cooker 22 are provided. A control circuit 26 for controlling the power supply device 24 and the like in accordance with an output of the temperature sensor 25 and a built-in rice cooking sequence is further provided. A lid 27 that can be opened and closed and a steam cylinder 28 that penetrates the lid 27 and communicates the inside of the rice cooker 22 with the outside air are provided.

The operation of these conventional rice cookers will be described.
When rice and water are put into the rice cooker 22 and the operation is started, the controller 26 controls the power supply 24 according to a built-in predetermined rice cooker sequence to heat the rice cooker and cook rice. The generated steam is discharged to the outside air via the steam cylinder 28.

[0004] However, in these rice cookers, one-time spilling of oneba through the steam cylinder 28 occurs during rice cooking due to factors such as the condition of the rice and the difference in the amounts of rice and water measured. There was something to do.

[0005]

However, in this type of conventional rice cooker, there is a possibility of unexpected spills, and these spills are absolutely acceptable when considering post-cleaning and safety. It was not an event, and contradicted to more tasty cooked rice, such as not being able to put enough heat to prevent them.

[0006] In addition, when erroneous use such as mistake in water level is assumed, as described above, there is a problem that needs to be solved from the viewpoint of post-cleaning and safety.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a heating device for a rice cooker, a control device for controlling an energized state of the heating device, and discharging steam in the rice cooker. The steam spill sensor includes a steam cylinder and a spill sensor arranged in the steam cylinder. The spill sensor covers an outer shell of the steam cylinder with a synthetic resin and sandwiches a PTC thermistor between metal plates.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a heating device for a rice cooker, a control device for controlling an energized state of the heating device, a steam tube for discharging steam from the rice cooker, and a steam tube. A spill sensor disposed in a cylinder, the spill sensor covering the outer shell with a synthetic resin, and sandwiching a PTC thermistor between metal plates to provide insulation and vapor between the plates. Insulation between the inside of the cylinder and the electrode plate can be secured at the same time, a sensor with higher safety can be realized, and furthermore, it is possible to safely prevent spilling over.

According to a second aspect of the present invention, the thickness of the sensor outer shell on the sensor receiving surface of the sensor shell of the front blow-off spill sensor toward the inside of the steam cylinder is smaller than the thickness of other sensor outer shells. By doing so, it is possible to improve the sensitivity of the blow-by sensor while ensuring insulation.

According to a third aspect of the present invention, by disposing the front electrode plate on the inner wall side of the sensor receiving surface of the blow-by sensor toward the inside of the steam cylinder and the rear electrode plate on the other inner wall side,
Adhesion with the PTC thermistor on the sensing surface side can be improved, and higher sensor sensitivity can be realized.

According to a fourth aspect of the present invention, the front electrode plate is disposed on the inner wall side of the sensor sensing surface of the blow-off sensor that goes into the steam cylinder, and the rear electrode plate is disposed on the inner wall side of the other surface. By making the wall thickness smaller than that of the rear electrode plate, adhesion between the PTC thermistor and the electrode plate is ensured, and more stable performance can be obtained.

[0012] According to a fifth aspect of the present invention, the thickness of a portion of the sensor receiving surface facing the PTC thermistor in which the thickness of the sensor outer shell is provided is reduced, the thickness of the other portions is increased, and the inner surface is formed. , The sensitivity can be maintained while receiving the pressing load from the rear electrode plate.

According to a sixth aspect of the present invention, a rib protruding toward the sensor receiving surface side is formed on the outer peripheral portion of a thin portion of the sensor receiving surface facing the PTC thermistor in which the thickness of the sensor outer shell is provided. By disposing the seal, the strength on the sensing surface side is secured, the contact surface with the wall of the steam cylinder is increased, the sealing performance is improved, the leakage of steam and oneva is prevented, and the positioning performance during assembly is improved. I do.

According to a seventh aspect of the present invention, a rib body for supporting a PTC thermistor is formed on each of an inner surface of a sensor outer shell and a part of an electrode plate supporting member for supporting the front and rear electrode plates. Heat conduction from the PTC thermistor to other than the sensor receiving surface can be reduced as much as possible, and the sensitivity can be further secured.

[0015]

FIG. 1 is a vertical sectional view of a substantially central portion of an electric rice cooker according to an embodiment of the present invention. Reference numeral 1 denotes a bottomed substantially cylindrical rice cooker 2, a heating coil 3 for heating the rice cooker 2 from below, an outer shell 4 covering them, and a lid 5 covering the upper opening of the rice cooker 2 so as to be openable and closable. An electric rice cooker main body (hereinafter referred to as a main body).

A power supply circuit 6 for energizing the heating coil 3 and the like, a temperature sensor 7 for detecting a temperature of a substantially bottom surface of the rice cooker 2 and a heating sensor 3 based on information of the temperature sensor 7 are provided inside the main body. A control device 8 for controlling the power supply circuit 6 and controlling the rice cooking sequence is provided.

9 is a rice cooker 2 provided on a part of the lid 5.
This is a steam cylinder that discharges the steam inside. Steam cylinder 9 is rice cooker 2
And the inflow port 10, and the outside of the rice cooker body 1 through an exhaust port 11. Reference numeral 12 denotes a spill sensor provided in the steam cylinder 9 and is connected to the control device 8.

FIG. 2 is a perspective view of the spill sensor 12. As shown in FIG. 13 is a sensor receiving surface for receiving oneva or bubbles when spilling into the steam cylinder 9;
It is formed in a concave shape compared to the peripheral portion. FIG. 3 is a cross-sectional view of the spill sensor 12. 14 has a positive temperature characteristic, and P is set at a Curie point exceeding 100 ° C.
As a TC thermistor element, it is sandwiched between a substantially flat front electrode plate 16 supported by an electrode plate support member 15 and a rear electrode plate 18 having an elastic portion 17 formed in a part thereof, and is formed of a resin box. It is inserted into the sensor outer shell 19. The front electrode plate 16 is inserted so as to be substantially in contact with the back surface side of the sensor sensing surface 13, and the PTC thermistor element is moved from the elastic portion 17 of the rear electrode plate 18 via the contact surface 18 a of the rear electrode plate 18. 14, and is pressed against the back surface of the sensor receiving surface 13 of the sensor outer shell 19 via the front electrode plate 16. The sensor outer shell 19 on the sensor receiving surface 13 is formed thinner than the other sensor outer shells 19. Each of the front electrode plate 16 and the rear electrode plate 18 is connected to the control device 8 via a drive circuit 20.

In the above-described configuration, the operation will be described.
When a start switch (not shown) connected to the controller is turned on, the controller 8 operates the power supply circuit 6 to heat the rice cooker 2 in accordance with a predetermined rice cooking process, thereby executing the rice cooking process.

A spill sensor 12 provided in the steam cylinder 9
When a voltage is applied by the drive circuit 20, PT
The C thermistor element 14 generates heat and is self-controlled at a temperature exceeding the Curie point. Due to this heat generation, the sensor receiving surface 13 is also maintained at a constant temperature exceeding 100 ° C.

The operation of the main unit 1 will now be described with the above configuration.
When a start switch (not shown) connected to the controller is turned on, the control device 8 operates the power supply circuit 6 to heat the rice cooker 2 according to a predetermined rice cooking process, and the predetermined rice cooking process built in the control device 8 is started. Execute and cook rice.

When a normal rice cooking process is performed and a rice cooking operation is performed, steam discharged to the outside of the main body after a certain period of time after the start of heating passes through the steam cylinder 9, but the steam is gaseous. Even when the vapor spill sensor 12 passes through the sensor receiving surface 13 in contact with the sensor, the amount of heat deprived from the sensor receiving surface 13 of the vapor spill sensor 12 is very small because the heat capacity of the steam itself is small. Does not change the temperature.

However, due to the above-mentioned requirements,
Immediately before a spill occurs, oneva or foam fills the rice cooker 2 and flows into the steam cylinder 9 as an opening from the inlet 10. At this time, the oneva and the bubbles that have flowed in contact with the sensing surface 13 of the blow-off sensor 12, and at the same time, remove heat from the sensing surface 13 to evaporate moisture. Accordingly, heat is removed from the PTC thermistor element 14 via the sensing surface 13 and the front plate 16. As described above, when the temperature of the PTC thermistor element 14 decreases, the internal resistance sharply decreases, and as a result, the current increases and attempts to return to the original temperature. The drive circuit 20 detects this change in current and sends a signal to the control device 8. The control device 8 operates the power supply circuit 6 to stop heating the rice cooker 2. Thus, the stoppage of the heating of the rice cooker 2 does not cause the spillover.

As described above, the spillover sensor 12 has the PTC thermistor element 14 sandwiched between the front electrode plate 16 and the rear electrode plate 18. The insulation between the electrode plate 16 and the rear electrode plate 18 can be ensured. In addition, as described above, the main spill sensor 12 faces the inside of the steam cylinder 9 and is exposed to steam, oneva, bubbles, and the like passing through the steam cylinder 9. It is possible to prevent a spill in a safer state.

Further, since the sensor outer shell 19 of the sensor receiving surface 13 of the blow-off sensor 12 is formed to be thinner than other portions, the portion of the sensor receiving surface 13 transmits heat most quickly. In addition to the above, by using a resin that is originally difficult to conduct heat, heat conductivity is poor in portions other than the sensor receiving surface 13.
3, which is less affected by other factors, less likely to receive disturbances, provides more stable and high-sensitivity sensor performance, and more reliably achieves prevention of blow-through.

The front electrode plate 1 is provided on the sensor receiving surface 13 side.
6, the adhesion between the electrode plate, the PTC thermistor element 14 and the front electrode plate 16 is improved by using the rear electrode plate front electrode plate 16 having an elastic portion 17 formed on a part thereof. Thereby, the sensitivity of the blow-by sensor 12 is further improved. As a result, earlier detection of a spill can be achieved, and prevention of a spill can be reliably achieved.

By making the sensor receiving surface 13 and the rear electrode 18 thinner than those, the speed of heat conduction from the sensor receiving surface 13 is improved, and the heat capacity of the front electrode 16 itself is reduced, thereby further improving sensitivity. Is what you do. As a result, earlier detection of a spill can be achieved, and prevention of a spill can be reliably achieved.

The front surface of the sensor plate 13 and the outer shell 19 of the sensor are made smoother on the back surface of the sensor receiving surface 13.
There is no useless gap or the like between them, and smoother heat conduction and accompanying rapid detection of spillage can be achieved, thereby reliably preventing spillage.

FIG. 4 is a cross-sectional view of a spillover sensor 21 according to another embodiment. The rib 22 is provided outward so as to surround the periphery of the sensor receiving surface 23 having a small thickness. On the back surface of the sensor sensing surface 23, a front electrode plate 24, a PTC thermistor element 25, and a rear electrode plate 27 having an elastic portion 26 are provided in this order.

The rear electrode plate 27 presses the PTC thermistor element 25 by its elastic portion 26, and further presses the front electrode plate 24 against the inner surface of the sensor receiving surface 23. The ribs 22 are provided around the thin sensor sensing surface 23 to protect the sensor sensing surface 23, prevent damage to the sensor sensing surface 23, improve the reliability of the spillover sensor 21, and prevent longer spillover. Performance can be achieved.

[0031]

As described above, the first aspect of the present invention provides
A heating device for the rice cooker, a control device for controlling an energized state of the heating device, a steam tube for discharging steam in the rice cooker, and a blow-off sensor disposed in the steam tube,
The spillover sensor covers the outer shell with a synthetic resin and sandwiches a PTC thermistor between metal plates, thereby simultaneously securing the insulation between the plates and the inside of the steam cylinder and between the plates. Thus, a sensor with higher safety can be realized, and thus, it is possible to safely prevent a spill.

Further, the thickness of the sensor shell of the sensor-receiving surface of the sensor shell of the front blow-off spill sensor toward the inside of the steam cylinder is compared with the thickness of the other sensor shell. By making it thin, it is possible to improve the sensitivity of the blow-by sensor while ensuring insulation.

According to a third aspect of the present invention, the front electrode plate is disposed on the inner wall side of the sensor-receiving surface facing the inside of the steam cylinder of the blow-off sensor, and the rear electrode plate is disposed on the inner wall side of the other surface. Adhesion with the PTC thermistor on the sensing surface side can be improved, and higher sensor sensitivity can be realized.

According to a fourth aspect of the present invention, the front electrode plate is disposed on the inner wall side of the sensor-receiving surface of the blow-off sensor which goes into the steam cylinder, and the rear electrode plate is disposed on the inner wall side of the other surface. By making the thickness of the plate thinner than that of the rear electrode, the adhesion between the PTC thermistor and the electrode can be ensured, and more stable performance can be obtained.

According to a fifth aspect of the present invention, the thickness of a portion of the sensor receiving surface opposite to the PTC thermistor in which the thickness of the sensor outer shell is provided is reduced, and the thickness of the other portions is increased. In addition, by smoothing the inner surface, the sensitivity can be maintained while receiving the pressing force from the rear electrode plate.

According to a sixth aspect of the present invention, the outer peripheral portion of the thinner portion of the sensor-receiving surface facing the PTC thermistor in which the thickness of the sensor outer shell is provided protrudes toward the sensor-receiving surface. By placing the ribs, the strength on the sensing surface side is secured, the contact surface with the wall of the steam cylinder is increased, the sealing performance is improved, the leakage of steam and oneva is prevented, and the positioning at the time of assembly is performed. To improve.

According to a seventh aspect of the present invention, a rib body for supporting a PTC thermistor is formed on an inner surface of a sensor outer shell and a part of an electrode plate supporting member for supporting the front and rear electrode plates. Accordingly, heat conduction from the PTC thermistor to a portion other than the sensor receiving surface can be reduced as much as possible, and the sensitivity can be further secured.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a rice cooker according to one embodiment of the present invention.

FIG. 2 is a perspective view of the blow-over sensor of the rice cooker.

FIG. 3 is a cross-sectional view of the spillover sensor of the rice cooker.

FIG. 4 is a cross-sectional view of another spillover sensor of the rice cooker.

FIG. 5 is a sectional view of a main part of a conventional rice cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rice cooker main body 2 Cooking pot 3 Heating coil 4 Outer shell 5 Lid 6 Power supply circuit 7 Temperature sensor 8 Control device 9 Steam cylinder 10 Inflow port 11 Exhaust port 12 Spillover sensor 13 Sensor sensing surface 14 PTC thermistor element 15 Pole plate support Member 16 Front electrode plate 17 Elastic portion 18 Rear electrode plate 18a Contact surface 19 Sensor outer shell 20 Drive circuit 21 Spill-over sensor 22 Rib 23 Sensor sensing surface 24 Front electrode plate 25 PTC thermistor element 26 Elastic portion 27 Rear electrode plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Nakae 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] 1. A heating device for a rice cooker, a control device for controlling an energized state of the heating device, a steam tube for discharging steam in the rice cooker, and a spill sensor disposed in the steam tube. A rice cooker in which the blow-off sensor has an outer shell covered with a synthetic resin and a PTC thermistor sandwiched between front and rear metal plates. 2. The rice cooker according to claim 1, wherein the spillover sensor has a thinner outer shell on the sensor receiving surface on the steam cylinder side than the others. 3. The rice cooker according to claim 1, wherein the spillover sensor has a front electrode plate on the inner wall side of the sensor receiving surface facing the inside of the steam cylinder and a rear electrode plate on the other inner wall side. 4. The rice cooker according to claim 3, wherein the thickness of the front electrode plate is smaller than that of the rear electrode plate. 5. The sensor receiving surface according to claim 1, wherein the thickness of a portion facing the PTC thermistor containing the thickness of the sensor outer shell is reduced, the thickness of the other portion is increased, and the inner surface is smoothed. Item 4. The rice cooker according to Item 1. 6. The rice cooker according to claim 5, wherein a rib protruding toward the sensor receiving surface side is arranged on an outer peripheral portion of a thin portion facing the PTC thermistor. 7. The rice cooker according to claim 1, wherein a rib body for supporting a PTC thermistor is formed on a part of an electrode plate supporting member for supporting an inner surface of a sensor outer shell, a front electrode plate, and a rear electrode plate.