JPH08280532A - Rice cooker - Google Patents

Abstract

PURPOSE: To accelerate the temperature rise at the time of a heating start and sufficiently improve the heating efficiency with an inexpensive structure. CONSTITUTION: An inner frame 20 is provided in a main body 12, the bottom section is closed with a glass plate 21, and a pot storage section 19 storing an aluminum pot 18 is formed. In the state where the pot 18 is stored, the upper opening section of the pot storage section 19 is closed. A heater unit 26 covered with a heater cover 27 is provided below the glass plate 21. The heater unit 26 stores a nearly circular halogen lamp heater 30 as a heating source in a shallow circular container-like heat insulating material 29. The surface of the heat insulating material 29 is formed into a reflector, and a conical projection 31 is integrally formed at the center portion. The sides of the pot storage section 19 and the heat insulating material 29 are closed so that no light is leaked to the outside.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rice cooker using a lamp heater such as a halogen lamp heater as a heating source.

[0002]

In the electric rice cooker, a sheathed heater is generally used as a heating source. However, since the sheathed heater has a large self-heat capacity and takes a long time to reach a high temperature, it has a drawback that the rice cooking time becomes long.

On the other hand, in recent years, rice cookers to which electromagnetic induction heating is applied as shown in FIG. 10 have been provided.
In this structure, a circular container-shaped inner frame 2 made of a material that allows a magnetic flux to pass therethrough, for example, a heat-resistant resin is arranged in a main body 1, and a bottom induction coil 3 is provided at the bottom of the inner frame 2 and the inner frame 2 A side induction coil 4 is provided around the lower part of the. Further, on the outside of the induction coils 3 and 4, a magnetically shielded ferrite 5 for preventing leakage of magnetic flux is arranged.

The inner frame 2 contains a pot 6 formed by press-molding a plate material obtained by joining a stainless material and an aluminum material, and receives the induction heating of the induction coils 3 and 4. As a result, the pot 6 itself generates heat to cook rice. Such an induction heating method has advantages over the one using a sheathed heater, such as good temperature distribution, delicious rice cooking, and quick rise in temperature during heating.

However, in the induction heating type rice cooker as described above, an expensive material must be used for the pot 6, and an oscillation circuit for obtaining a high frequency is required. There is a problem that it becomes expensive.
Further, there is a drawback that the energy loss such as copper loss generated in the induction coils 3 and 4 is large and the heating efficiency is low.

The present invention has been made in view of the above circumstances, and an object thereof is that the temperature rises quickly at the start of heating, the cost can be reduced, and the heating efficiency can be sufficiently improved. To provide a rice cooker.

[0007]

A rice cooker according to the present invention is provided with a pot accommodating portion having an opening at the top in a main body, and the opening is closed in a state in which the pot is accommodated in the pot accommodating portion. And a lamp heater as a heat source located below the pan housed in the pan housing section, and a reflector located below the lamp heater (claim 1). invention).

According to this structure, the pot accommodated in the pot accommodating portion is mainly heated by the heat rays from the lamp heater located below to cook rice, but the lamp heater having a rapid heating property is used as the heating source. Therefore, the temperature rises quickly at the start of heating, and the cost can be reduced as compared with the case where induction heating is adopted. When the pot is in the stowed state, the opening at the top of the pot stowage is closed by the pot, so that light and heat can be prevented from escaping from the opening of the pot stowage, and the lamp heater irradiates downward. The generated heat rays are reflected by the reflector and used for heating the pot above.

In this case, an outer reflector may be provided which is located on the outer side of the lamp heater and expands upward (invention of claim 2). According to this, the light radiated outward from the lamp heater can also be used for heating the pot by reflecting it upward.

Further, the lamp heater is accommodated in the heater accommodating portion, and the heater accommodating portion and the pan accommodating portion are
The side portion may be closed so that the light of the lamp heater does not leak to the outside (invention of claim 3). According to this, light does not leak to the outside from the heater accommodating portion and the pan accommodating portion, the heat rays emitted from the lamp heater can be efficiently used for heating the pan, and the heat rays leaking to the outside It is possible to prevent adverse effects on members and the like.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention (corresponding to claims 1 and 3) will be described below with reference to FIGS. First, the configuration of the rice cooker 11 according to the present embodiment will be described with reference to FIGS. 1 to 5.

FIG. 1 shows the overall structure of the rice cooker 11, in which the outer shell of the main body 12 is composed of an outer frame 13 and a bottom case 14 in the shape of a rounded rectangular container as a whole. A lid 15 is rotatably provided on the upper surface of the main body 12 via a hinge 16. In addition, an operation unit 17 having various operation keys and a display unit including an LCD is provided on a slope portion 13a of the outer frame 13 from the front surface to the top surface of the main body 12.

In the main body 12, there is provided a pan accommodating portion 19 for accommodating the pan 18 in and out. Here, the pot 18 is made of, for example, an aluminum material, and has a circular container shape with an open upper surface. The pot housing section 19
In this case, in this case, a flat glass plate 21 is arranged so as to close the bottom of the inner frame 20 having a cylindrical shape whose upper and lower surfaces are open as a whole. Has an opening for inserting and removing. When the pan 18 is housed in the pan housing portion 19, the bottom surface of the pan 18 is placed in close contact with the upper surface of the glass plate 21, and
The outer periphery of the upper end portion of the pan closes the upper end opening of the pan receiving portion 19.

In this case, the inner frame 20 is made of an iron plate plated with an alloy of zinc and aluminum having substantially the same ratio, and the surface thereof has a high light reflectance. The inner frame 20 is an upper inner frame 20a having a diameter slightly larger than the pot 18.
And a lower inner frame 20 having a diameter slightly larger than that of the upper inner frame 20a.
b, and the inner diameter of the lower portion is larger than the inner diameter of the upper portion, so that the lower inner peripheral portion of the inner frame 20 (the lower inner frame 20b) and the lower outer peripheral portion of the pan 18 are formed. A space for reflecting light is formed between and.

The inner frame 20 is fixed to the outer frame 13 by a flange portion 20c provided on the upper end thereof. Further, the flange portion 20c is provided with a sealing material 22 which tightly seals between the outer periphery of the upper end portion of the pot 18 and the inner frame 20 when the pot 18 is accommodated in the pot accommodating portion 19. . Further, on the outer peripheral portion of the upper inner frame 20a,
A body heater 23 for keeping the rice warm is provided, and an upper temperature sensor 24 and a lower temperature sensor 25 for contacting the outer peripheral surface of the pot 18 to detect the temperature of the pot 18 are provided on the lower inner frame 20b. Has been.

The glass plate 21 is fixed to the flange portion 20d at the lower end of the inner frame 20, and
A heater cover 27 that supports the heater unit 26 is fixed. The glass plate 21 is made of crystallized glass having high strength, high thermal shock resistance, and high heat ray permeability, and is fixed to the flange portion 20d so as to extend from below. At this time, as shown in FIG. 2, a plurality of through holes 2 serving as resistance to heat transfer are provided in a portion of the outer peripheral portion of the glass plate 21 which is addressed to the flange portion 20d.
1a is formed. A ring-shaped sealing material 28 having high heat resistance is provided between the upper surface of the glass plate 21 and the inner peripheral surface of the lower end of the inner frame 20.

Now, regarding the heater unit 26,
It will be described with reference to FIGS. 2 to 4. This heater unit 2
In this case, 6 is constituted by accommodating a halogen lamp heater 30 as a heat source in a heat insulating material 29 which is in the shape of a shallow bottom circular container as a whole. Therefore, the heat insulating material 29 has a function as a heater accommodating portion. The heat insulating material 29 is made of a ceramic material, and its surface (inner surface) is finished to reflect light to some extent.
It also has a function as a reflector.
The heat insulating material 29 is composed of a bottom portion 29a and a ring-shaped peripheral wall portion 29b which are separately formed, and has a diameter substantially equal to that of the inner frame 20 (lower inner frame 20b).

As shown in FIG. 3, the halogen lamp heater 30 is formed in a substantially annular shape in which both end portions are close to each other, corresponding to the outer peripheral portion of the bottom surface of the pot 18, and the both end portions are provided with a bottom portion 29a and a peripheral wall. It is supported by the heat insulating material 29 so as to be sandwiched between it and the portion 29b. Terminal portions 30a, 30 at both ends
a is located outside the heat insulating material 29. In this embodiment, the halogen lamp heater 30 is AC100.
It uses a 1200V rated V.

In this embodiment, a conical convex portion 31 is integrally formed on the upper surface of the heat insulating material 29 (bottom portion 29a) at the central portion of the halogen lamp heater 30. , As shown in FIGS. 3 and 4,
An inclined convex portion 32 having an inclined reflection surface located between both ends of the halogen lamp heater 30 and directed to both ends of the halogen lamp heater 30 (rightward and leftward in FIGS. 3 and 4).
Are integrally formed.

Further, as shown in FIGS. 1 and 2, on the lower surface side of the heat insulating material 29, a heater mounting plate 33 having a diameter slightly larger than that of the heat insulating material 29 has a slight gap (air layer). Is stuck to. The heater unit 26 configured as described above is supported while being accommodated in the heater cover 27.

That is, the heater cover 27 has a container shape which is slightly larger than the heater unit 26, and as shown in FIG. 1, three rod-shaped guide members 34 (1) provided on the lower surface of the heater mounting plate 33. (Only one is shown) is vertically movably inserted into a hole formed in the bottom surface of the heater cover 27, and a coil spring 35 as an elastic body is provided around the outer periphery of the guide members 34. Thus, the heater unit 26 is supported inside the heater cover 27 in a state of being urged upward.

By fixing the upper end portion of the heater cover 27 to the flange portion 20d at the lower end of the inner frame 20, the halogen lamp heater 30 has the glass plate 21 with the heat insulating material 29 arranged in the lower portion. Is arranged on the lower surface side of the glass plate 21. At this time, the upper end of the heater unit 26 (heat insulating material 29) is pressed against the lower surface of the glass plate 21 by the urging force of the coil spring 35. As a result, the heat insulating material 29 as the heater accommodating portion and the pan accommodating portion 19 are closed at their side portions so as not to leak the light of the lamp heater 30 to the outside to form a closed space. .

A heat insulating plate 36 is provided on the lower surface side of the heater cover 27 so as to have an air layer. Also,
As shown in FIG. 1, a control unit 38 having a control unit 37 (see FIG. 5) including a microcomputer is provided on the front side of the main body 12 (outer frame 13).
A cord reel portion 39 for accommodating a power cord (not shown) is provided on the back side in 3). Further, a lid heater 40 is provided on the lower surface of the lid 15 to prevent dew condensation.

FIG. 5 schematically shows the electrical construction of the rice cooker 11 having the above construction. That is, the rice cooker 11 is connected to the power source 41 (AC100V) through the power cord,
An alternating current is applied to the halogen lamp heater 30 via a power control element 42 such as a thyristor.

On the other hand, a control unit 37 including a microcomputer or the like receives a setting signal by the operation of the operation keys of the operation unit 17 by the user, and the upper temperature sensor 2
4 and the detection signals of the lower temperature sensor 25 are A / D converter 43.
It is designed to be input via. In this case, the upper temperature sensor 24 detects boiling of water in the pot 18,
The lower temperature sensor 25 detects the hot water temperature and the completion of cooking. Based on these input signals, the control unit 37 performs the required display on the display unit according to the control program, and also controls the power control element 42 to be turned on and off via the phase angle varying unit 44, and the halogen lamp heater 30. The energization control is performed.

In this case, as will be described later in the explanation of the operation, the control unit 37 reduces the input power to the halogen lamp heater 30 by phase control at the beginning of the energization of the halogen lamp heater 30 when it is cold. The control for increasing the input power (100% energization) is performed after a certain period of time. In addition, DC for circuits such as the control unit 37
Power is supplied via the DC power supply unit 45. Although not shown in FIG. 5, the body heater 23 and the lid heater 40 are also controlled by the controller 37.

Next, the operation of the above configuration will be described with reference to FIGS. 6 and 7. For example, when the user wants to cook white rice, the user stores the pan 18 containing the required amount of rice and water in the pan storage portion 19 and operates the operation key to operate the menu (white rice, cook, Rice porridge, etc.) and heat (strong, normal,
(Weak, etc.) is selected, and an instruction to start the rice cooking operation or reservation setting of the cooking time is performed.

Here, as shown in the flow chart of FIG. 6, when the rice cooking operation is started, the halogen lamp heater 30 is energized.
Is started (step S1), and the power control element 42 is turned on at a phase angle of 140 ° by the phase control (step S2). Thus, as shown in FIG. 7, the waveform of the current flowing through the halogen lamp heater 30 at the beginning of the energization is (b) with respect to the waveform of the power supply voltage (a).
It becomes a small current like. Even with a small current, the filament of the halogen lamp heater 30 is instantly heated.

Then, when the value of the timer T reaches a preset predetermined time T0 (for example, 5 ms) (Yes in step S3), the power control element 42 is turned on at the phase angle of 0 ° (step S3). S4), as shown in FIG. 7C, the halogen lamp heater 30 is 100% energized. After that, the normal rice cooking operation is executed. As a result, the rush current can be suppressed, and problems such as the breaker operating can be prevented in advance. In addition, the control in step S2 is several Hz.
Since it finishes in the order of, there is no loss of fast heating.

In the halogen lamp heater 30, the filament temperature exceeds 2000 ° K when 100% energized,
Light having a distribution having a peak wavelength of 1000 nm in the infrared region is output. This light passes through the glass plate 21 and is applied to the pan 18 to heat the pan 18, and the heat generated by the halogen lamp heater 30 itself also heats the glass plate 21.
Is transmitted to the pot 18 via. The radiant heat due to light is transmitted to the pan 18 immediately after the start of energization, so that the temperature rises rapidly during heating. At this time, since the surface of the heat insulating material 29 located below the halogen lamp heater 30 functions as a reflector, the heat rays emitted downward from the halogen lamp heater 30 are reflected on the surface of the heat insulating material 29. It comes to be used for heating the upper pot 18.

The light from the halogen lamp heater 30 has a high reflectance in the space between the lower inner peripheral portion of the inner frame 20 and the lower outer peripheral portion of the pot 18 as shown by an arrow A in FIG. The pot 18 is reflected on the inner surface of the inner frame 20 and is heated by the radiant heat of the light from the lower side surface side as well so as to wrap it from below. In addition to this, the halogen lamp heater 30 is formed in an annular shape corresponding to the outer peripheral portion of the bottom surface of the pan 18, so that the pan 18
The outer peripheral side of the bottom surface of the
As indicated by arrow B, the convection of the water in the pan 18 can be made suitable for rice cooking such that the convection in the pot 18 rises outside and descends in the center, as in the case of cooking a traditional oven. You will be able to do that.

Further, since the conical convex portion 31 is integrally formed in the central portion of the upper surface of the heat insulating material 29, the halogen lamp heater 30 is caused by the reflected light (indicated by the arrow C in FIG. 2) at the conical convex portion 31. The heating on the center side of the pot 18 which is slightly away from the pan 18 can be supplemented, and at the same time, since the inclined convex portion 32 is integrally formed on the heat insulating material 29 at the portion between both ends of the halogen lamp heater 30, The light reflected by the inclined convex portion 32 can supplement the heating in the portion between both ends of the halogen lamp heater 30.

Since the halogen lamp heater 30 is surrounded by the heat insulating material 29 in its lower part and lateral sides, and the heat insulating material 29 is in close contact with the glass plate 21, the light and heat from the halogen lamp heater 30 are directed downward and to the side. It is prevented as much as possible to escape. Moreover, since the outer periphery of the upper end portion of the pan housing portion 19 (inner frame 20) and the pan 18 are closed, it is possible to prevent light and heat from escaping to the upper part through the side of the pan 18. Thus, the pot 18 can be heated extremely efficiently.

Further, since the heater mounting plate 33, the heater cover 27, the heat insulating plate 36, etc. are provided to form an air layer outside the heater unit 26, the heat can be shielded downward and sideward from the heater unit 26. Well done,
The inside of the outer frame 13 and the bottom case 14 are not exposed to high temperatures. Further, since the glass plate 21 is arranged on the bottom of the pot housing portion 19, when spilled juice etc. from the pot 18, the dirt adheres to the flat and smooth glass plate 21 and is easily wiped off. Therefore, the sealing material 28 prevents the simmered liquid from leaking to the outside.

As described above, according to the present embodiment, since the halogen lamp heater 30 is used as the heating source, unlike the conventional sheath heater, the temperature rise at the start of heating can be accelerated and the rice cooked. The time can be shortened. Further, compared to the one shown in FIG. 10 which uses induction heating, a complicated oscillation circuit, expensive induction coils 3, 4 and pot 6 are not used, so that a significant cost reduction can be achieved. Since the heat insulating material 29 functioning as a reflector is provided below the halogen lamp heater 30 and there is no copper loss in the induction coils 3 and 4, a sufficiently high heating efficiency can be obtained.

Moreover, in this embodiment, the upper end opening of the pan containing portion 19 is closed by the pan 18, and the pan containing portion 19 and the heat insulating material 29 (heater unit 2) are used.
Since it is configured so that light and heat do not leak to the side from 6),
The heating efficiency can be further improved, and at the same time, adverse effects due to high temperature of external members and the like can be prevented in advance.

Further, particularly in the present embodiment, various measures such as integrally providing the heat insulating material 29 with the conical convex portion 31 and the inclined convex portion 32, and forming the inner surface of the inner frame 20 from a material having a high reflectance, etc. As a result, the heating efficiency can be further improved, and the temperature distribution of the pan 18 can be improved so that delicious rice can be cooked. In addition, since the glass plate 21 is arranged at the bottom of the pot housing portion 19, it is possible to improve the cleaning performance and also to obtain the advantage of excellent usability.

FIG. 8 shows a second embodiment of the present invention (claim 2).
The difference from the first embodiment lies in the configuration of the heater unit 51. That is, the heater unit 51 is configured such that the ring-shaped halogen lamp heater 30 is supported by the heat insulating material 52 that is in the shape of a shallow-bottom circular container as a whole. Instead of the conical convex portion 31, a separate conical reflector 53 is provided, and further, on the inner peripheral wall portion of the heat insulating material 52,
A ring-shaped reflector 54 serving as a tapered outer reflector is provided so as to surround the outer circumference of the halogen lamp heater 30 and expand upward. The conical reflector 53 and the ring reflector 54 are made of a metal plate, for example, a stainless steel plate plated with chromium, and have high heat resistance and high light reflectance.

According to this structure, as in the first embodiment, the light reflected by the conical reflector 53 can compensate for the heating of the center of the pot 18 slightly away from the halogen lamp heater 30. In addition to this, the light output laterally (outer peripheral direction) from the halogen lamp heater 30 is reflected upward by the ring-shaped reflector 54, so that the heating efficiency can be further improved. .

FIG. 9 shows a third embodiment of the present invention. In the heater unit 61 of the present embodiment, a reflector made of a metal plate (for example, a chrome-plated stainless plate) is provided between the ring-shaped halogen lamp heater 30 and the heat insulating material 62 having a shallow circular container shape. The reflector 63 is provided.

The reflection plate 63 has a conical convex portion 63 located at the central portion and corresponding to the conical reflector 53.
a is integrally formed, and a tapered inclined surface portion 63b located at the outer peripheral portion and corresponding to the ring-shaped reflector (outer reflector) 54 is integrally formed. Even in such a configuration, it is possible to further improve the heating efficiency and optimize the temperature distribution by the reflected light from each part of the reflection plate 63.

Although not shown, on the upper surface of the heat insulating material,
Instead of the inclined convex portion 32 in the first embodiment, a metal plate-shaped reflector having inclined reflection surfaces facing both ends of the halogen lamp heater 30 may be provided. Further, in each of the above-mentioned embodiments, the glass plate 21 is provided at the bottom of the pan containing portion 19, but the glass plate 21 may be omitted. In this case, the flange portion at the upper portion of the pan 18 is provided in the pan containing portion 19. It can be configured to be supported on the peripheral portion of the (inner frame 20). A through hole may be provided in the glass plate 21.

Further, in each of the above embodiments, the heat insulating materials 29, 52 and 62 are provided below the halogen lamp heater 30, but the necessary heat insulating property (heat shielding property) is obtained by providing an air layer or the like. It may be configured as follows. In this case, the inside of the heater accommodating portion does not necessarily have to be a closed space as a whole, and a through hole may be formed in a part of the bottom of the heater accommodating portion. In addition, the present invention can be implemented by appropriately changing the present invention within the scope not departing from the gist such that a straight tube type halogen lamp heater may be used.

[0044]

As is apparent from the above description, according to the rice cooker of the first aspect of the present invention, the lamp heater having a rapid heating property is used as the heating source, and the light is emitted from the opening of the pot housing part. Since it is designed to prevent escape and to use the heat rays radiated downward from the lamp heater by the reflector to heat the pot, the temperature rises quickly at the start of heating, and an inexpensive configuration is sufficient. In addition to the above, it has an excellent practical effect that the heating efficiency can be sufficiently increased.

In this case, the heating efficiency can be further improved by providing an outer reflector located on the outer side of the lamp heater and expanding upward (rice cooker according to claim 2). Further, if the light from the lamp heater is prevented from leaking outward from the heater housing portion and the pan housing portion housing the lamp heater (rice cooker according to claim 3), the heating efficiency is further improved. In addition, it is possible to prevent adverse effects on external members and the like due to leakage of heat rays.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention, and is a vertical sectional side view of the whole.

FIG. 2 is a vertical sectional side view of a main part.

FIG. 3 is a plan view of a heater unit.

FIG. 4 is a vertical cross-sectional view of the heater unit taken along line IV-IV in FIG.

FIG. 5 is a block diagram showing an electrical configuration.

FIG. 6 is a flowchart showing a control procedure at the beginning of energization.

FIG. 7 is a diagram showing a current waveform flowing through a halogen lamp heater.

FIG. 8 is a diagram corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 9 is a vertical sectional side view of a heater unit showing a third embodiment of the present invention.

FIG. 10 is a view corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

In the drawing, 11 is a rice cooker, 12 is a main body, 13 is an outer frame, and 17
Is an operating unit, 18 is a pan, 19 is a pan containing portion, 20 is an inner frame, 20a is an upper inner frame, 20b is a lower inner frame, and 20c, 2
0d is a flange portion, 21 is a glass plate, 21a is a through hole, 2
2 is a sealing material, 26, 51, 61 are heater units, 2
7 is a heater cover, 29, 52 and 62 are heat insulating materials, 30 is a halogen lamp heater (lamp heater), 31 is a conical convex portion, 32 is an inclined convex portion, 35 is a coil spring, 37 is a control portion, and 42 is electric power. A control element, 53 is a conical reflector, 54 is a ring reflector (outer reflector), and 63 is a reflector (reflector).

Claims (3)

[Claims] 1. A pot accommodating portion having an opening at an upper portion is provided in the main body, and the opening is closed in a state where the pot is accommodated in the pot accommodating portion and is accommodated in the pot accommodating portion. A rice cooker provided with a lamp heater as a heat source located below the cooked pot and a reflector located below the lamp heater. 2. The rice cooker according to claim 1, further comprising an outer reflector that is located outside the lamp heater and that spreads upward. 3. The lamp heater is housed in a heater housing part, and the heater housing part and the pan housing part are
The rice cooker according to claim 1 or 2, wherein a side portion is closed so that light of the lamp heater does not leak outward.