JPH0540835Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention controls the power supply to the rice cooking heater using a center thermometer that uses a temperature-sensitive magnetic material whose magnetism suddenly changes as the temperature rises. Lead
This invention relates to a rice cooker that uses a temperature-sensitive switch such as a TRS switch to control power supply to a heat-retaining heater.

<Conventional technology> Traditionally, rice cookers detect the presence of a rice bowl as an object to be heated and allow electricity to be applied to the rice heater only when the rice bowl is set, thereby preventing dry cooking. Additionally, a center thermostat is provided that is in contact with the center of the bottom of the rice bowl in order to stop energizing the rice cooking heater and shift to the steaming process when the temperature of the bottom of the rice bowl reaches a predetermined value or higher.

The structure of a conventional rice cooker in the vicinity of the above-mentioned center thermostat is shown in FIG. The rice cooker consists of a main body 50 and a lid unit 51. The main body 50 houses an inner container 54 in a cylindrical outer container 53 via a heat insulating material 52, and a rice container 5 is placed inside the inner container 54.
5 is detachably accommodated. A ring-shaped rice cooking heater 57 holding a nichrome wire 56 in an embedded state is disposed on the bottom surface of the inner container 54, and a center thermostat 60 is disposed in a hollow portion at the center of the rice cooking heater 57. The rice cooker 55 includes a top plate 61 of a center thermostat 60 and a rice cooker heater 57.
It is housed in the inner container 54 with its bottom surface in close contact with the inner container 54.

A heat-retaining heater 58 is provided on the outer periphery of the side surface of the inner container 54 to keep the rice warm after cooking. This heat-retaining heater 58 is operated by a thermal reed switch (TRS) 59 that is disposed on the side of the inner container 54 at a position that is not easily affected by the heat generated by the heat-retaining heater 58 and detects the temperature of the rice bowl 55. Electricity is controlled, thereby maintaining the temperature of the rice in the rice bowl 55 at approximately 70°C. 75 is a temperature fuse.

The center thermostat 60 includes an inner case 62 to which a top plate 61 is fixed at the upper end by caulking the edges thereof, an outer case 63 that houses the inner case 62, and an outer case 63 disposed within the outer case 63. The inner case 62 is provided with a coil spring 64 that urges the inner case 62 upward. A temperature-sensitive magnetic material 65 that rapidly loses its magnetism when heated to a predetermined temperature is fixed to the surface of the top plate 61 on the inner side of the inner case 62. Inside the inner case 62, a permanent magnet piece 66 is held at a position facing the temperature-sensitive magnetic body 65, and
A holding member 68 biased downward by a coil spring 67 is housed. At the lower part of the holding member 68, an inner case 62 and an outer case 6 are provided.
A lever 69 is attached that is inserted through the bottom of each of the parts 3 and 3, and the holding member 68 can be moved up and down by this lever 69.

The tip of the operating lever 70 is rotatably connected to the tip of the lever 69 . Operation lever 7
0 is pulled out to the outside of the outer container 53,
A rice cooking switch 71 made of synthetic resin is fixed. The operating lever 70 is supported by a support shaft 72 provided near the rice cooking switch 71, and when the rice cooking switch 71 is pushed down, the tip thereof rotates upward, and the holding member 68 is rotated through the lever 69. push upward. A switch operation part 74 is provided between the support shaft 72 and the tip end of the operation lever 70 that connects the lever 69 to conduction/cutoff of a micro switch 73 for controlling electricity supply to the rice cooking heater 57. There is. As a result, when the tip of the operating lever 70 is displaced upward as shown by the solid line in FIG. When the tip of the operating lever 70 is positioned downward as shown by the two-dot chain line in the figure, the micro switch 73 is shut off and the rice cooking heater 57 is not energized.

When the rice bowl 55 is not set in the inner container 54, the top plate 61 is moved by the action of the coil spring 64.
is in a state of protruding from the ring-shaped rice cooking heater 57. In this state, the rice cooker switch 71
Even if the holding member 68 is displaced upward by pressing down, the distance between the temperature-sensitive magnetic body 65 and the permanent magnet piece 66 is relatively large, so the attractive force between the two is small, so the permanent magnet piece 66 is moved upward. It cannot be attracted to the magnetic body 65. For this reason, the rice cooker switch 71
After the operation, the operating lever 70 returns to the position indicated by the two-dot chain line in FIG. 3, and the micro switch 73 is thereby shut off. In this way, rice bowl 5
5 is not set, power supply to the rice cooking heater 57 is prohibited.

On the other hand, when the rice bowl 55 is set in the inner container 54,
Since the top plate 61 is displaced downward, the rice cooking switch 7
By pushing down the holding member 68 and displacing the holding member 68 upward, the permanent magnet piece 66 can be attracted to the temperature-sensitive magnetic body 65 against the spring force of the coil spring 67. It is held at the position shown by the solid line in the figure. As a result, the microswitch 74 is maintained in a conductive state, allowing electricity to be supplied to the rice cooker heater 57, thereby heating the rice cooker 55.

As the rice cooker 55 is heated by the rice cooker heater 57, the temperature of the rice cooker 55 rises and reaches a predetermined temperature. The temperature-sensitive magnetic body 65 loses its magnetism, and as a result, the holding member 68 falls due to the spring force of the coil spring 67 and the gravity acting on the permanent magnet piece 66 and the like. As a result, the switch operating portion 74 of the operating lever 70 shuts off the micro switch 73. As a result, the power supply to the rice cooking heater 57 is stopped, and the process moves to the shading step.
After this, the TRS 59 controls the energization of the warming heater 58 to keep the cooked rice warm.

FIG. 4 is an electrical circuit diagram showing the electrical configuration of the rice cooker described above. The power from the commercial AC power supply 80 is supplied to the temperature fuse 75 and the micro switch 7.
3 to the rice cooking heater 57. A series circuit of a TRS 59 and a heat retention heater 58 is connected in parallel to the micro switch 73, and a heat retention lamp 81 that indicates the heat retention state is connected in parallel to this series circuit.
is connected. Further, a rice cooking lamp 82 for displaying the rice cooking status is connected in parallel to the rice cooking heater 57. Reference numeral 83 denotes a lid heater provided on the upper surface of the inner lid (not shown) to evaporate water droplets generated on the surface of the inner lid. In place of the lid heater 83, a shoulder heater (not shown) provided on the shoulder of the main body 50 (see FIG. 3) may be used, and the inner lid may be heated by heat conduction from the shoulder heater. be.

With the above configuration, when the micro switch 73 becomes conductive, the rice cooking heater 57 is energized, and this is indicated by the lighting of the rice cooking lamp 82. On the other hand, when the micro switch 73 is shut off due to the end of rice cooking, the heat retention heater 58 is turned off via the TRS 59.
energization is performed, and this is indicated by lighting of the heat retention lamp 81. The heat retention operation after this is as follows.
This is achieved by controlling the supply of electricity to the heat-retaining heater 58 by turning on/off the TRS 59.

<Problems to be Solved by the Invention> In the above configuration, the center thermometer 60 and the TRS 59, both of which detect the temperature of the rice bowl 55, are separately attached to the side and bottom of the inner container 54, respectively. For this reason, the number of man-hours required to assemble the rice cooker was large, making the assembly work complicated. Moreover,
Detection of the temperature of the rice bowl 55 by the TRS 59 is based on the air layer 85 created between the rice bowl 55 and the TRS 59.
Since the detection accuracy is not necessarily high, it has been difficult to perform the heat keeping operation with high precision.

Therefore, the purpose of the present invention is to provide a rice cooker that solves the above-mentioned technical problems, simplifies assembly work, and enables accurate temperature control during heat retention. do.

<Means for Solving the Problems> The rice cooker of the present invention to achieve the above object has a rice bowl housed in an inner container, and heats the rice bowl by magnetic change of a temperature-sensitive magnetic material. In a rice cooker that controls the power supply to the rice cooker heater and also controls the power supply to the warming heater that keeps the rice bowl warm using a temperature-sensitive switch, there is a A storage box is provided with a top plate that comes in contact with the storage box, and temperature-sensitive magnetic materials and temperature-sensitive switches are arranged horizontally along the bottom surface of the top plate inside the storage box. do.

<Function> According to the above configuration, the temperature-sensitive magnetic material that controls the energization to the rice cooking heater and the temperature-sensitive switch that controls the energization to the heat-retaining heater are housed in a common storage box. It can be formed as a single unit, simplifying wiring and facilitating assembly work.

Further, since the temperature-sensitive magnetic bodies and the temperature-sensitive switches are arranged horizontally along the lower surface of the top plate, the temperature-sensitive magnetic bodies and the temperature-sensitive switches sense the temperature of the same top plate. Then, the power supply to the rice cooking heater is controlled by the magnetic change of the temperature-sensitive magnetic material that detects the temperature of the top plate, and the rice is switched from cooking to keeping the rice warm, but when keeping the rice warm, it detects the same temperature of the top plate as the temperature-sensitive magnetic material. The temperature-sensitive switch works. Therefore, the temperature detected by the temperature-sensitive magnetic material and the temperature-sensitive switch is the temperature of the top plate that the rice bowl has contacted.
Since the temperature at the same location is detected, after the rice cooking state is switched from the rice cooking state to the warming state due to a change in the magnetic properties of the temperature sensitive magnetic material, the power supply control to the warming heater based on the temperature detection by the temperature sensing switch is reliably started.

<Examples> Examples will be described in detail below with reference to the accompanying drawings showing examples.

FIG. 1 is a longitudinal sectional view showing the structure of a center thermostat used in a rice cooker according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof. This center thermostat is fixed by a cylindrical outer case 1 to the center of the bottom of an inner container (not shown) that removably accommodates a rice bowl in a rice cooker. A cylindrical inner case 2 serving as a storage box is attached to the outer case 1 by hooking a locking portion 2a formed at its lower end onto the edge of a locking hole 3 formed at the bottom of the outer case 1. It is being At the top of the inner case 2, there is a temperature-sensitive magnetic material 4 in the shape of a disk with a part removed.
and TRS (thermal lead), which is a temperature-sensitive switch.
The temperature-sensitive magnetic body 4 and TRS 5 are attached by caulking the edge 7a of the top plate 7 using a mounting bracket 6 to which the switch) 5 is fixed. The mounting fitting 6 has a through hole 10 formed in the area where the temperature sensitive magnetic body 4 is located, and is provided with a J-shaped holding portion 11 for holding the TRS 5. Both the top plate 7 and the mounting bracket 6 are
For example, it is made of a material with good thermal conductivity, such as aluminum.

Therefore, in the inner case 2 serving as a storage box, the temperature-sensitive magnetic body 4 and the TRS 5, which is a temperature-sensitive switch, are arranged horizontally along the lower surface of the top plate 7. Therefore, both the temperature-sensitive magnetic body 4 and the TRS 5 are configured to be able to accurately detect the temperature of the top plate 7.

One end of a coil spring 12, which is disposed so as to cover the inner case 2, is in contact with the edge 7a of the top plate 7. The other end of this coil spring 12 is in contact with the bottom surface of the outer case 1, and urges the inner case 2 upward. When a rice bowl (not shown) is not set, upward displacement of the inner case 2 is restricted by the locking portion 2a. The lead wire 17 connected to the TRS 5 is connected to a hole 18 formed at the bottom of the inner case 2 and a hole 19 formed at the bottom of the outer case 1.
and is guided to a wiring board (not shown).

Inside the inner case 2, there is a holding member 14 that holds the permanent magnet piece 13 at a position facing the temperature-sensitive magnetic body 4.
is stored. This holding member 14 is regulated from downward displacement by a support portion 2b formed by bending the lower end of the inner case 2 inward, and is controlled by a coil spring 15 provided inside the inner case 2. upward displacement is regulated.

A lever 16 extending downward is attached to the holding member 14, and an operation lever (not shown) connected to this lever 16 allows the holding member 14 to be moved by the spring force of the coil spring 15 from outside the rice cooker. It can be displaced upwardly against the resistance. The operation lever is used to conduct/cut off a micro switch (not shown) that controls electricity supply to a rice cooking heater (not shown), and when the holding member 14 is displaced upward, the micro switch is turned on/off. In the state shown in FIG. 1 in which the holding member 14 is displaced downward, the microswitch is in the cutoff state.

In the state where the rice cooker is not set (the state shown in FIG. 1), the distance between the temperature-sensitive magnetic body 4 and the permanent magnet piece 13 is sufficiently large, so that the permanent magnet piece 1
3 will not be attracted to the temperature-sensitive magnetic body against the spring force of the coil spring 15. In addition, even if the holding member 14 is displaced upward by operating the operating lever in this state, the permanent magnet piece 13 is held by operating the operating lever so that the permanent magnet piece 13 is not attracted to the temperature-sensitive magnetic body 4. The amount of upward displacement of member 14 is limited. Therefore, when the rice cooker is not set, even if the operating lever is operated, the holding member 14 will not be held in an upwardly displaced state, thereby prohibiting power supply to the rice cooking heater. This prevents empty cooking.

On the other hand, when the rice bowl is set, the inner case 2 is displaced downward against the spring force of the coil spring 12 due to the weight of the rice bowl and its contents. In this state, the temperature-sensitive magnetic body 4 is at a sufficiently lower position, so the distance between the holding member 14 and the permanent magnet piece 13 is sufficiently shortened by operating the operation lever, so that both It is attracted against the spring force of the coil spring 15. Therefore, the above-mentioned microswitch is maintained in a conductive state, thereby allowing power to be supplied to the rice cooking heater, and the rice cooking operation is performed.

Furthermore, when the contents of the rice cooker are heated by energizing the rice cooker and the temperature of the bottom of the rice cooker reaches a predetermined temperature (approximately 140 to 150°C), the temperature-sensitive magnetic body 4 turns off its magnetism. lose. As a result, the attraction of the permanent magnet piece 13 to the temperature-sensitive magnetic body 4 is released, and the holding member 14 is displaced downward by the biasing force of the coil spring 15. Therefore, the above-mentioned operating lever shuts off the microswitch, thereby stopping power supply to the rice cooking heater.

After rice is cooked, the TRS 5 controls the power supply to a heat-retaining heater (not shown), thereby keeping the temperature of the contents in the rice bowl constant. Since the TRS 5 is fixed to the mounting bracket 6 that is in direct contact with the top plate 7,
It can accurately detect the temperature at the bottom of the rice bowl.
This allows the above-mentioned heat retention operation to be performed satisfactorily.

In the rice cooker of this embodiment using the center thermo as described above, the temperature-sensitive magnetic material 4 and the TRS 5 are arranged horizontally in contact with the bottom surface of the top plate that contacts the rice cooker. , the temperature-sensitive magnetic body 4 and the TRS 5 are attached by a common attachment fitting 6. Therefore, fewer mounting members are required, the mounting is easy, and the assembly work can be significantly simplified.

Furthermore, since the temperature-sensitive magnetic bodies 4 and TRS 5 are arranged horizontally along the lower surface of the top plate 7, both the temperature-sensitive magnetic bodies 4 and TRS 5 can detect the temperature of the top plate 7 with high accuracy. Therefore, the temperature-sensitive magnetic material 4
After the switching control from rice cooking to keeping warm is performed due to the magnetic change, the temperature of the top plate 7 is subsequently detected by the TRS 5, and the keeping warm control is performed satisfactorily.

<Effects of the invention> As described above, according to the rice cooker of the invention, the temperature-sensitive magnetic material that controls the electricity supply to the rice-cooking heater and the temperature-sensitive switch that controls the electricity supply to the heat-retaining heater are housed in a common storage box. Because they can be housed in one unit and configured as a single unit, wiring for both is easy.
Moreover, the assembly work of the rice cooker can be simplified.

Further, since the temperature-sensitive magnetic material and the temperature-sensitive switch are arranged horizontally along the lower surface of the top plate in the storage box, both can accurately detect the temperature of the top plate. As a result, the temperature-sensitive magnetic body detects the temperature of the top plate and its magnetism changes, and after the control is switched from cooking to keeping rice warm, the temperature-sensitive switch also accurately detects the temperature of the top plate and maintains good heat. Control takes place. In this way, after switching from cooking to keeping warm, the keeping-warm control is performed smoothly.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the configuration of a center thermometer used in a rice cooking jar according to an embodiment of the present invention, Fig. 2 is an exploded perspective view thereof, and Fig. 3 shows the configuration of a conventionally used rice cooking jar. FIG. 4 is a partially cutaway side view and an electric circuit diagram showing its electrical configuration. 2... Inner case (storage box), 4... Temperature-sensitive magnetic material, 5... TRS (temperature-sensitive switch), 6... Mounting bracket, 7... Top plate, 13... Permanent magnet piece, 2
2...Inner case (storage box), 24...Temperature-sensitive magnetic material, 25...Permanent magnet piece, 26...Lid, 3
0... Aluminum block, 31... Top plate, 33...
TRS (temperature sensitive switch).

Claims (1)

[Scope of Claim for Utility Model Registration] It has a rice cooker housed in an inner container, and controls power supply to a rice cooker that heats the rice cooker by changing the magnetic properties of a temperature-sensitive magnetic material. In a rice cooker that controls the power supply to a heat-retaining heater that keeps the rice bowl warm, a storage box is provided at the bottom of the inner container in which the rice bowl is stored, and has a top plate that comes into contact with the outer bottom surface of the rice bowl. The rice cooker is characterized in that temperature-sensitive magnetic bodies and temperature-sensitive switches are arranged horizontally along the lower surface of the top plate.