JP2003045630A - Cooling method of electromagnetic induction heating cooker and cooling structure used for it - Google Patents

Abstract

(57) [Summary] To provide sufficient cooling without a fan by a bulky heat sink. SOLUTION: Solid portions 201a, 201b, which are thermally coupled to heat-generating electronic components 63, 64 and have a higher heat conductivity than the heat-generating electronic components 63, 64, have a heat capacity larger than the heat-generating electronic components 63, 64. The solid portions 201a and 201b have a higher thermal conductivity and a larger heat capacity than the heat-generating electronic components 63 and 64, so that heat is transferred from the heat-generating electronic components 63 and 64 while cooling. The above object is achieved by storing the heat and maintaining the cooling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cooling an electromagnetic induction heating cooker which heats a cooking device such as a pot or a cooking plate by electromagnetic induction to cook various kinds of heat such as cooked rice, boiled rice, grilled food, fried food, and fried food. For details, regarding a method for cooling an electromagnetic induction heating cooker in which heat is generated by electromagnetic induction from a work coil for heating and cooking, but heat-generating electronic components in a work coil energization / control circuit are cooled by a heat sink, and a cooling structure used therefor. It is about.

[0002]

2. Description of the Related Art Electromagnetic induction heating is performed by generating an alternating magnetic field in a work coil by a switching function of a semiconductor switching element (IGBT) and generating an eddy current in an opposing cooker by the alternating magnetic field to generate heat. On this occasion,
An exothermic electronic component that heats up due to heat generated by the IGBT and the diode bridge (DB) that controls the input of the IGBT,
If these are not kept below a predetermined temperature, it may cause malfunction such as malfunction of itself or melting of the soldered portion.

Therefore, conventionally, as shown in FIG. 7, a heat sink c made of aluminum is brought into contact with these heat-generating electronic components a and b to take heat and dissipate the heat through the fins d, thereby cooling the heat sink. The conventional example shown in FIG. 7 is an example of a case where the heat sink c has a shape which is arranged so as to avoid the cord reel e, the temperature sensor f in the center of the cooking device, and the like. On the other hand, Japanese Unexamined Patent Publication No. 08-154815 discloses a technique in which a semiconductor switching element is heat-conductively contacted with a metal portion of a body case via a heat dissipation plate having heat conductivity and is cooled without a fan and a heat sink. is doing. FIG. 8 shows another conventional example, except that a specific positional relationship between the heat sink c and the heat-generating electronic components a and b and the control board g having these heat-generating electronic components a and b is shown. There is no particular difference from the conventional example of FIG.

[0004]

In the conventional cooling method using the heat sink c with fins, if the heat sink c is forcibly cooled by blowing air with a fan, it is also effective in an electromagnetic induction heating cooker having a large heating capacity. However, if the fan is omitted in order to save energy, the cooling effect is greatly reduced, and it can be applied only to one having a small heating capacity. This is because when the heat sink c is cooled without a fan, the natural convection and flow of the surrounding air become slow and slow, and the air tends to stay between the narrow fins d, so that the cooling effect of the fin d decreases. It seems to be the cause. In order to deal with this without a fan, it is necessary to increase the number of fins d and increase the distance between the fins d, and the heat sink c becomes considerably bulky, which is not practical.

Further, in the conventional cooling method utilizing the heat coupling structure with the metal case body, the case body has a metal part even if sufficient cooling is possible without a fan. It is inconvenient because it is subject to restrictions, and the temperature of the metal part of the body case rises, which may give the user anxiety and distrust.

An object of the present invention is to provide a cooling method for an electromagnetic induction heating cooker capable of performing sufficient cooling without a fan by a heat sink that is not bulky, and a cooling structure used for the method.

[0007]

In order to achieve the above-mentioned object, the electromagnetic induction heating cooker of the present invention heats and cooks a cooker such as a pot or a cooking plate by electromagnetic induction with a work coil. In the cooling method of the electromagnetic induction heating cooker in which the heat generating electronic parts in the work coil energization / control circuit are cooled by the heat sink, the heat generating electronic parts are thermally coupled to and have higher thermal conductivity than the heat generating electronic parts. The heat sink is provided with a solid portion having a heat capacity larger than that of the heat-generating electronic component, and this solid portion has higher heat conductivity and larger heat capacity than the heat-generating electronic component, thereby transferring heat from the heat-generating electronic component. It is characterized in that the heat is accumulated while being cooled as planned to continue the cooling. Here, the thermal coupling means direct or indirect contact with each other so that heat can be transferred between them, and indirect contact may be used, for example, so as to be advantageous for heat transfer or mechanical coupling.

As described above, the solid portion of the heat sink is thermally coupled to the heat-generating electronic component, so that the solid portion of the heat sink has a higher thermal conductivity and a larger heat capacity than the heat-generating electronic component. Continuing to transfer the heat of electronic components to the solid part of the heat sink while this solid part is not thermally saturated with static heat radiation to the surroundings,
It is possible to continue to cool the heat-generating electronic components without forced movement of the air by the fan, and also to cool the heat-generating electronic components sufficiently depending on the heat capacity of the solid parts. Since the sufficient cooling can be achieved with a volume around the bulky area formed by the conventional fins provided to exert a sufficient cooling effect without a fan, the electromagnetic induction heating cooker does not become particularly large. Practicality is not impaired.

When the solid parts of the heat sink are individually made to correspond to a plurality of heat-generating electronic parts to perform the cooling, the respective heat-generating electronic parts corresponding to the respective solid parts are accumulated with each other or correspond to each other. Stabilize the cooling performance by preventing the heat capacity of the heat generating electronic parts other than the heat generating electronic parts from inadvertently breaking the relationship of the thermal capacity with the corresponding heat generating electronic parts in each solid part. Can be achieved.

When the heat of the heat sink is taken away by the heat radiating plate thermally coupled to the heat sink to radiate the heat to continue the cooling, the heat of the heat sink is taken away by the heat radiating plate, and the solid portion of the heat sink is removed. The required heat capacity or volume is small and the heat sink is heat-coupled with the surrounding air in a wide area without taking up much space due to the spread of the surface in a shape adapted to the surrounding area. Convection and flow due to temperature difference etc. can be freely performed without restraining or staying in place to achieve efficient cooling without a fan, and the miniaturization is promoted by cooling the heat sink, thus reducing the cooling effect. The heat sink can be made smaller and lighter without the overall size becoming larger.

The cooling structure of the electromagnetic induction heating cooker which achieves the above method is such that the cooking coil such as a pot or a heating cooking plate is heated by electromagnetic induction by the work coil to perform the heating and cooking. In the cooling structure of the electromagnetic induction heating cooker that cools the heat-generating electronic components in the energization / control circuit with the heat sink, to the heat sink that is thermally coupled to the heat-generating electronic components and has higher thermal conductivity than the heat-generating electronic components,
It suffices that a solid part having a larger heat capacity than the heat-generating electronic component is provided and a heat sink is thermally coupled to this heat sink, and the heat sink is a natural introduction of outside air in the outer case of the rice cooker body. Preferably, it is located in the air passage where natural discharge takes place.

If the heat sink has a structure in which the heat coupling area with the heat radiating plate is larger than the heat coupling area with the heat generating electronic component, the heat sink takes advantage of the size of the heat sink to take the heat taken from the heat generating electronic component. Since the heat-dissipating plate having a larger size than that between the heat-generating electronic components and the heat-dissipating surface can quickly move to the heat-dissipating plate side having high cooling efficiency, the cooling effect of the heat-generating electronic components can be enhanced.

If the volume of the solid portion of the heat sink is equal to or larger than the volume of the corresponding heat-generating electronic component, even if it receives the heat of the entire heat capacity of the heat-generating electronic component, it will not be saturated including static heat radiation to the surroundings. The advantage of being able to continue cooling the heat-generating electronic components for a long time only by static heat transfer is that the remaining surface area of the solid part is larger than the heat-bonding area of the heat-generating electronic parts. The effect of sustaining cooling by heat transfer can be enhanced, and the area of thermal coupling with a heat sink or the like can be further increased.

If the heat sink has a heat capacity or volume that does not cause temperature equilibrium or temperature rise during the heating operation of the cooking process, not only the fan but also the natural convection and flow of air are generated. Since it is possible to continue cooling the heat-generating electronic components throughout the cooking process only by using pure static heat transfer, which is not used, it is easy to guarantee the required cooling performance.

In each of the above cases, the heat sink is made of an aluminum material, which is suitable for cooling and weight reduction. However, it is not limited to this.

Further, in the structure in which the circuit board having the heat generating electronic component and the heat radiating plate are connected to each other in a substantially L-shape at the heat coupling portion via the heat sink, the heat generating electronic component, the heat sink, and the heat radiation The thermal coupling through the heat sink that moves the heat in the order of the plates to cool the heat-generating electronic components is satisfied by the connection structure in which the circuit board and the heat dissipation plate are substantially L-shaped, and is formed inside the body of the electromagnetic induction heating cooker. The dead space having a substantially L-shaped cross section formed by the bottom portion and the body portion is used to facilitate the placement, and the heat dissipation plate is opened in the body without being covered with the circuit board or approaching in a substantially parallel manner.
The cooling effect is improved because the surrounding air is not restricted and flows easily.

Further objects and features of the present invention will become apparent from the following detailed description and drawings. The features of the present invention can be used alone or in combination in various combinations as much as possible.

[0018]

EXAMPLES Examples of an electromagnetic induction heating cooker according to the present invention will be described below in detail with reference to FIGS. 1 to 4 for understanding of the present invention.

The electromagnetic induction heating cooker of this embodiment is an example of the case of an electromagnetic induction rice cooker that cooks rice and keeps it warm by electromagnetic induction heating. However, it is not limited to this,
It is effective when applied to various types of electromagnetic induction heating cookers that perform various types of cooking such as cooking rice, boiled rice, grilled foods, stir-fried foods, and fried foods by making a cooking device such as a pot or a cooking plate generate heat by electromagnetic induction. It belongs to the category of invention.

The electromagnetic induction rice cooker of this embodiment is shown in FIG. 1 to FIG. 3 as one example and in FIG. 4 as another example. The overall configuration of them is almost the same as shown in FIGS. 1 and 4, respectively, and a pot 3, a hollow container 1 for accommodating the pot 3 in a removable manner, and a pan of this container 1 A bottom inner work coil 4 and a bottom outer work coil 10a, which are provided around the inner wall 6 forming the accommodating portion and which face the center and the outer periphery of the bottom of the pot 3, and a body heater 13 which faces the body of the pot 3. , A shoulder heater 33 provided on the shoulder portion of the body 1, and a bottom inner work coil 10b, a bottom outer work coil 10a, a body heater 13, and a shoulder heater 33 for a rice cooking step, a rice cooking amount, and rice cooking. An operation panel 43, which controls various driving states according to the difference in heat retention and has an operation switch, is provided on the front part of the body 1.
It is provided inside. Further, drive circuits 59 and 60 for the body heater 13 and the shoulder heater 33 as shown in FIG.
Further, the drive circuit 62 having a heat generating element such as the IGBT 63 and a diode bridge (BD) 64 for controlling the drive input thereof is provided on the control board 143. The body 1 is formed by connecting an outer wall 5 and an inner wall 6 made of synthetic resin with a shoulder member 7 made of synthetic resin. However, the material of the part or the whole of the body 1 is not particularly limited. The outer wall 5 uses the heat of the pan 3 and the heat of the IGBT 63, DB 64, etc. to heat the air in the body 1 to cause convection and flow. For example, air is exhausted from an exhaust port 41 provided between the bottom portion 5b and the like, and intake is made from an intake port 15 provided in the bottom portion 5b. Air is circulated in the body 1 by the exhaust air and the intake air. The air passage 14 is formed.

The lid 2 provided on the body 1 is detachably fitted to a hinge piece 20 pivotally supported by a hinge pin 101 on the rear portion of the body 1 so as to be integrated with the hinge piece 20. The upper end of the body 1 can be opened and closed by turning. A spring 102 for urging the lid 2 in the opening direction is applied to the hinge piece 20 between the hinge piece 20 and the body 1. A braking mechanism for braking the opening operation due to the biasing of the spring 102 is provided as necessary, and a locking claw 42 biased by a spring (not shown) is provided so as to lock the lid 2 in the closed position so as not to open it arbitrarily. When the lock claw 42 is rotated against the spring, the lid 2 is automatically opened by the bias of the spring 102.

The shoulder heater 33 is housed in a groove 31 formed in the upper surface of the shoulder portion of the body 1, is provided with a metal cover 32, and has a metal double inner lid 28, 34 provided inside the lid 2. The outer peripheral portion of the upper inner lid 28 comes into contact with the metal cover 32 so that the shoulder heater 33
Heat is conducted to the entire area of the opening of the pan 3 through the lower inner lid 34, and the cooked rice is heated evenly from the upper portion. A pressure regulating valve 23 is provided at the center of the lid 2 to regulate the pressure inside the pot 3 during rice cooking while allowing steam to escape to the outside properly so that delicious rice can be cooked.
The outer wall 5 and the inner wall 6 of the body 1 have shoulder members 7 at their upper ends.
Are connected and integrated to form a synthetic resin container. Synthetic resin has magnetic permeability, and it is effective if the work coils 10a, 10b and the like are provided in a range where the pan 3 is heated by electromagnetic induction, but other parts do not have such effectiveness, and other members. Can be replaced.

The lid 2 has a heat insulating structure in which a space 18 between a synthetic resin upper plate 16 and a lower plate 17 is filled with a heat insulating material 19.
A pressure regulating valve 23 provided in a central portion of an upper metallic inner lid 28 penetrates the through hole 21 in the central portion from below and is elastically engaged by an elastic bush 104 so as to be detachable. The pressure regulating valve 23 is screwed or caulked from the upper side to the inner metal lid 28 on the upper side, and the hanging pin 35 protruding from the central portion of the pressure regulating valve 23 to the lower side of the inner lid 28 is attached to the lower metal lid 34. An elastic bush 36 provided in the central portion of the above is elastically fitted so as to be detachable.

When the upper inner lid 28 is attached to the lid 2,
Seal packing 30 whose outer periphery is provided on the lid 2 side
When the lid 2 is closed, the inner lid 28 has a sealing member 29 mounted in a groove on the outer periphery of the lower surface of the pot 3a of the pot 3 when the lid 2 is closed. The pot 3 is closed by crimping to the rim and the outer periphery of the lower inner lid 34 is also crimped from the outside.

In this state, the steam generated in the pan 3 enters between the lower inner lid 34 and the pressure-bonded portion of the seal member 29 by its own pressure and enters between the upper inner lid 28 and the inner lid 28. Through the steam hole 25 of the inner lid 28, the steam inflow hole 26 of the pressure regulating valve 23, the ball valve 24 in the steam passage 22 in the pressure regulating valve 23, and the steam outlet 27 facing the outside of the pressure regulating valve 23 to the outside. Be escaped to. At this time, the ball valve 24 appropriately suppresses the escape of steam and maintains the inside of the pan 3 at a predetermined rice cooking pressure. In the discharge of steam for such pressure adjustment, oneva accompanies the steam is accumulated on the inner lid 34 and the inner lid 28, but both of them including the lid 2 can be separated independently. , Each can be washed as a whole and kept clean for a long time.

A radial coil base 11 made of synthetic resin is arranged around the bottom of the inner wall 6 of the double container 1 to hold the work coils 10a and 10b from below. A ferrite core 12 is provided in a downward recess 11a formed in each radial portion of the coil base 11 to assist the work coils 10a and 10b. A temperature sensor 8 is provided at the center of the coil base 11 to penetrate the center hole 9 of the inner wall 6 and contact the bottom of the pot 3 to detect the temperature of the pot 3.

The operation panel 44 displays menus such as rice cooking and heat retention, operating states, time, and other messages.
A liquid crystal display unit 53 as shown in FIG. 3 is provided in the center, and a start key 45 for starting cooking rice around the left and right sides and a front side of the liquid crystal display unit 53, a reservation key 46 for making a rice cooking time reservation, a cancel key 47 for various inputs, Heat retention key 48 to artificially start heat retention, reheat key 49 to reheat to a temperature higher than the heat retention temperature for eating or sterilization, menu key 50 for setting menu of rice cooking and heat retention, time setting The operation keys necessary for various settings such as the key 51 and the minute key 52 are provided.

In both examples, the control circuit is shown as a representative in FIG. 3, and is mainly composed of the control board 143. Explaining this, the AC power supply 54, via the power supply fuse 55, the body heater 13 and the shoulder heater 33,
Power is supplied to the rectifier circuit 56. Power is supplied to the body heater 13 and the shoulder heater 33 through respective drive circuits 59 and 60. The rectifier circuit 56 supplies power to the drive circuit 62 having the IGBT 63 via the smoothing capacitor 57, and the work coils 10a and 10b via the resonance capacitor 58.
To generate an alternating magnetic field. At this time, the temperature of the pan 3 which generates heat due to electromagnetic induction is monitored by the sensor 8.

The sensor 8 and the start key 45 to minute key 52 on the operation panel 44 are connected to the input port of the microcomputer 61 on the control board 143, and the liquid crystal display 53 is connected to the input / output port. Each of the drive circuits 59, 60 and 62 is connected to the output section.

In each of the example shown in FIGS. 1 to 3 and the example shown in FIG. 4, the pan 3 which is an example of a cooking device is heated by electromagnetic induction by the work coils 10a and 10b on the outside of the bottom and the inside to cook. In order to perform the above, the IGB which is an example of heat generating electronic parts in the control board 143 as an energization / control circuit for the work coils 10a and 10b on the bottom outer side
Although the T63 and DB64 are cooled by the heat sink 201, they are thermally coupled to these IGBT63 and DB64 and I
The heat sink 201 having higher heat conductivity than the GB63 and DB64 is provided with the solid portions 201a and 201b having a larger heat capacity than the IGBT63 and DB64, and the solid portions 201a and 201b have higher heat conductivity and heat capacity than the IGBT63 and DB64. Is large, IG
The basic feature is that the heat from the BT 63 and the DB 64 is transferred while being cooled and the heat is accumulated to maintain the cooling.

As described above, the solid parts 201a and 201b provided on the heat sink 201 and the IGBT 63 and DB 64 are provided.
By thermally coupling the corresponding ones to each other, the solid parts 201a and 201b of the heat sink 201 become IG
Utilizing the fact that it has higher thermal conductivity and larger heat capacity than BT63 and DB64, the heat of the IGBT63 and DB64 is transferred to the solid parts 201a and 201b of the heat sink 201 by the static heat dissipation to the surrounding parts of the IGBT63 and DB64. The IGBT 63 and the DB 64 can be continuously cooled without being forcedly blown by the fan as well as the natural movement of the air 204 by continuing the transfer while not being thermally saturated. Therefore,
Depending on the heat capacity of the solid portions 201a and 201b, it can be cooled sufficiently. In particular, since it is possible to achieve the sufficient cooling with a volume around the bulky area formed by the conventional fins provided to exert a sufficient cooling effect without a fan, an electromagnetic induction heating cooker such as an electromagnetic induction rice cooker. However, there is no particular increase in size and practicality is not impaired.
In short, the solid portions 201a and 201b are formed by substituting the conventional fins, and the bulkiness of the whole does not change significantly. However, as an example, the conventional finned heat sink weighed about 200 g, but the heat sink 201 of the present embodiment in which the solid portions 201a and 201b were formed weighed about 494 g.
This difference in weight is the difference in heat capacity and volume between the two.

Further, as shown in FIG. 2 as a representative, the solid portions 201a and 201b of the heat sink 201 are adapted to individually cool the IGBTs 63 and DB64 as a plurality of heat generating electronic components, respectively. IGBT63, DB6 corresponding to each solid part 201a, 201b
In order to cool 4, the heat accumulation of each other influences each other, or the heat of the corresponding heat generating electronic components other than the IGBT 63 and DB 64,
Specifically, the solid portion 201a is a heat generating electronic component other than the IGBT 63, which is a corresponding heat generating electronic component, and is DB64.
Of the IGBT 63, which is a heat-generating electronic component other than the corresponding heat-generating electronic component DB64, does not affect the respective solid-state parts 201b, and the corresponding IGBTs in the respective solid-state parts 201a and 201b.
It is possible to prevent the relationship of the thermal capacity between 63 and DB 64 from being carelessly broken, whereby the cooling performance is stabilized as designed.

Further, as shown in FIGS. 1 and 2, and as shown in FIG. 4, the heat of the heat sink 201 is transferred to the heat sink 2
The heat radiating plate 202 thermally coupled to 01 removes the heat to dissipate the heat to the periphery to continue the cooling. In this way, the heat of the heat sink 201 is absorbed by the heat radiating plate 202, so that the solid portions 201a and 201b of the heat sink 201 become small in size with small necessary heat capacity or volume, and the heat radiating plate 202 has a shape adapted to the surroundings. 1 and 4 of the surface of FIG. 4 and the surface of the surrounding air 204 does not take up much space and is thermally coupled to the surrounding air 204 in a large area, and the surrounding air 204 is not restrained or stayed and the temperature difference etc. Since the convection and the flow can be freely performed by the air conditioner to efficiently cool the heat sink 201 and to promote the miniaturization by cooling the heat sink 201, the heat sink 201 can be cooled without reducing the cooling effect or increasing the overall size. Can be made smaller and lighter.

As a cooling structure for achieving the above cooling method, in the example shown in FIGS. 1 to 3, as shown in FIGS. 1 and 2, the IGBT 63 and DB 64 on the control board 143 are connected to the solid portion of the heat sink 201. The heat sinks 201a and 201b are directly contacted with each other and thermally coupled to each other.
The thermal conductivity is higher than that of T63 and DB64, and IG
The heat on the BT63 and DB64 sides is transferred to the solid portions 201a and 201b on the heat sink 201 side, that is, heat is conducted. Further, the heat sink 201 including the solid portions 201a and 201b thereof is in direct contact with and thermally coupled to the heat dissipation plate 202. More specifically, the control board 143 and the heat dissipation plate 202 are applied to the upper and lower sides of the heat sink 201 and screwed simultaneously or individually with a screw 203 to be integrated so that the mutual thermal coupling state can be firmly maintained. There is. But such integration
It can be carried out by various methods such as sandwiching, welding, and adhesion, and various methods can be combined and employed. A mounting hole 205 is provided in the heat sink 201 for screwing.

The heat sink 201, as shown in FIG.
Two solid parts 201a on both sides avoiding the temperature sensor 8 and the cord reel 206 provided in the center of the bottom of the body 1,
By distributing 201b, a small flat space around the center of the bottom of the body 1 is provided, and the control board 143 and the heat radiating plate 202 sandwiching it from above and below effectively provide a horizontally wide space in the bottom of the body 1. 2 can be used for placement, and in particular, one solid portion 201b is shown in FIG.
As shown in (2), it is formed by branching in two directions in contact with two adjacent surfaces of the DB 64, and the heat of the DB 64 is taken away from the two directions by the two solid portions 201b so that it can be cooled earlier. In this way, if a plurality of solid parts correspond to one heat-generating electronic component and are thermally coupled, cooling can be achieved earlier. Heat generating electronic components to heat sink 2
In order to achieve a quicker heat transfer to 01 by direct contact, it is preferable to use screwing or the like to increase the degree of close contact with each other at the contact portion. However, it is also possible to indirectly fill the heat bond by filling a filler having good thermal conductivity between the contact portions.

In the example shown in FIG. 4, the IGBT 63,
The control board 143 having the DB 64 and the heat sink 202 are
Both are substantially L-shaped and connected by a heat coupling portion 207 via a heat sink 201. Specifically, for example, the heat dissipation plate 202 is provided on the downward surface 201c of the heat sink 201.
One end side of the heat sink 201 is fastened with a screw 203, and the heat radiating plate 202 extends from the heat sink 201.
The lower end of 3 is applied and screwed with a screw 203 to connect them.

In this way, the IGBT 63, the DB 64, the heat sink 201, and the heat dissipation plate 202 are transferred in this order by heat transfer to I
The thermal coupling via the heat sink 201 that cools the GBT 63 and the DB 64 is satisfied by the connection structure in which the control board 143 and the heat dissipation plate 202 are substantially L-shaped, and is formed in the body 1 of the electromagnetic induction rice cooker. A dead space having a substantially L-shaped cross section formed by the bottom and the body as shown in FIG. 4 is used to facilitate the placement. At the same time, the heat sink 202 is attached to the control board 14
3 is opened in the body 1 without covering or coming close to each other substantially in parallel, and the surrounding air 204 is not restricted and flows easily, so that the cooling effect is improved.

In any of the example shown in FIGS. 1 to 3 and the example shown in FIG. 4, the heat radiating plate 202, as shown in FIG. 1 and FIG. It is located in the air passage 14 formed between the mouth 41. As a result, the heat dissipation plate 202 is exposed to the flow of the air 204 that is naturally discharged to the outside of the body 1 and is naturally sucked into the body 1, so that the heat sink 201, and thus the IGBT 63,
The DB 64 can achieve dynamic cooling using the flow of air 204 via the heat dissipation plate 202. The air passage 14 may be formed in any route, but it is preferable that the more active convection or flow of the air 204 can be utilized.

The heat sink 201 is composed of the IGBT 6
3, the heat coupling area (contact area in this example) with the heat dissipation plate 202 is larger than the heat coupling area (contact area in this example) with the heat-generating electronic component such as DB 64, so that the heat sink 201 The heat taken away from the heat-generating electronic components is quickly transferred to the heat-dissipating plate 202 side having high cooling efficiency through the heat coupling surface with the heat-dissipating plate 202, which is larger than that between the heat-generating electronic components by utilizing the size of the heat sink 201. Since it is transferred, the cooling effect of the heat generating electronic components such as the IGBT 63 and the DB 64 can be enhanced.

Further, the solid portion 20 of the heat sink 201
The volumes of 1a and 201b correspond to the corresponding IGBT 63, DB
Because the volume of heat-generating electronic components such as 64 is more than
Even if it receives the heat of the entire heat capacity of the heat-generating electronic component, it does not saturate including static heat radiation to the surroundings, and it has the advantage that it can continue to cool the heat-generating electronic component for a long time only by static heat transfer. By making the remaining surface area of 201a and 201b larger than the thermal coupling area with the heat-generating electronic component, the cooling continuation effect by static heat transfer can be enhanced,
It is possible to further increase the thermal coupling area with the heat dissipation plate 202 or the like.

If the heat sink 201 has a heat capacity or volume that does not cause temperature equilibrium or temperature rise during the heating operation of the cooking process, the fan 204 and the air 204 naturally. IGBT63, DB by purely static heat transfer without using any convection or flow
Since the heat generating electronic components such as 64 can be continuously cooled during the rice cooking process, that is, during the heating and cooking process, it is easy to guarantee the required cooling performance.

As described above, the heat sink 201 made of an aluminum material is suitable for cooling and weight reduction. However, the material is not limited to this, and other materials having high thermal conductivity such as a body can be used.

Here, showing an example of an experiment at an output of 530 W, the data shown in Table 1 below is 49 in this example.
It is the temperature of each electronic component etc. when the actual rice of 3 pieces of white rice is cooked in the cooling structure using the heat sink 201 of 4 g, is an example of starting the rice when the DB sensor is at room temperature, is after the rice is cooked This is an example in which rice cooking is started after the DB sensor has cooled to 59 ° C. This is because the upper limit temperature of the DB sensor for starting rice cooking is about 60 ° C.

[0044]

[Table 1] According to the data, the temperature of the DB sensor at the end of rice cooking is 61.8.
It took 4 minutes and 00 seconds for the temperature of the DB sensor to drop to 59 ° C., and after this time, actual data cooking was performed. The actual cooking rice was in the normal mode, whereas the actual cooking rice was in the quick cooking mode. Here, the above-mentioned 4 minutes and 00 seconds is a waiting time required between the previous rice cooking and the rice to be continuously cooked thereafter. Continuous cooked rice is insufficient in capacity of the electromagnetic induction cooker for the required amount of cooked rice, and it is necessary to cook rice in several batches or to use different types of rice such as white rice and cooked rice, pilaf rice, etc. , IGBT63, DB64, and other heat-generating electronic components cannot be cooled sufficiently, the waiting time in the case of continuous cooking becomes long.

The data when the output is 640 W is shown in Table 2 below.

[0046]

[Table 2] On the other hand, the data shown in Table 3 below is the output of 530 W corresponding to the case of Table 1 when the cooling structure using the conventional finned heat sink 200 g type is used.
This is the temperature of each electronic component when rice is cooked. The rice cooked in is normal mode.

[0047]

[Table 3] The temperature of the DB sensor at the end of cooking rice is 64.6 ° C, which is slightly lower than 3 ° C as compared with the case of the data in Table 1. Therefore, it takes 9 minutes and 30 seconds for the temperature of the DB sensor to drop to 59 ° C., which is more than double the waiting time for continuous rice cooking.

As is clear from the above, the heat sink 201 of this embodiment has a higher cooling effect for the heat-generating electronic components than the conventional finned heat sink, and the continuous rice cooking performance or continuous cooking performance is significantly improved.

Here, the temperature such as the temperature of the DB sensor that determines whether or not continuous rice cooking or continuous cooking is monitored is monitored, and while the temperature exceeds a predetermined value, control is performed to limit continuous cooking and cooking. If the cooking is performed on the substrate 143 or the like, it is possible to automatically prevent wrong cooking of rice. When making such a restriction, it is preferable to warn the user of that. The warning is a buzzer,
Any of onomatopoeia, character display, lamp display, etc. may be used, or a combination thereof may be used.

The heat sink 201 of this embodiment is
The solid portion 201 has a volume corresponding to the conventional fin installation area.
The fins for enhancing the cooling effect may be provided after securing them in a and 201b, and the heat radiating plate 202 and the control board 143 may be provided with ventilation holes and bent portions for enhancing the cooling. Further, as shown in FIGS. 1 and 4, the inner wall 6 of the body 1 is
In order to prevent the temperature of the heat-generating electronic components from rising, it is necessary to provide a protective wall 211 that surrounds the outer periphery of the pan to prevent the heat on the pan 3 side from reaching the control board 143 and the heat dissipation plate 202. When the protective wall 211 is made of a metal material such as a heat shield plate, a part of it can be shared with the heat dissipation plate 202, and the heat dissipation plate 202 can be thermally coupled to the protection wall 211. The protective wall 211 may be used for cooling the heat-generating electronic component.

5 and 6 show another embodiment of the present invention,
By providing an intake port 15 on the bottom of the outer wall 5 of the body 1 and an exhaust port 41 on the upper part of the body 5b, and widening the air passage 14, the convection of air in the body 1 is activated,
The heat sink 201 is designed to be sufficiently cooled without a heat sink. In addition, the heat sink 201 applied to the lower surface of the control board 143 is extended downward by the space of the widened air passage 14 to increase the heat capacity or the contact area with the air 204 and absorb heat from the heat generating electronic components. It is easy and cool.

Other than that, the body heater is omitted, the shoulder 7a of the body 1 is integrally formed on the body 5b of the outer wall 5 to connect with the inner wall 6, and the shoulder member is omitted. There is no particular change except that the lid structure is simplified, and the same members as those in the above-described embodiment are designated by the same reference numerals, and the duplicated description will be omitted.

[0053]

According to the present invention, a cooker such as a pot or a cooking plate is heated by electromagnetic induction by a work coil to perform heating and cooking, and a heat-sink is used for a heat-generating electronic component in an energization / control circuit of the work coil. In a cooling method of an electromagnetic induction heating cooker for cooling, a heat sink that is thermally coupled to a heat-generating electronic component and has a higher thermal conductivity than the heat-generating electronic component is provided with a solid portion having a larger heat capacity than the heat-generating electronic component. Since the solid portion has higher heat conductivity and larger heat capacity than the heat-generating electronic component, the heat from the heat-generating electronic component is transferred to the cooling unit and is cooled while the heat is stored to maintain the cooling. It is characterized by that.

As described above, the solid portion provided on the heat sink and the heat-generating electronic component are thermally coupled to each other, so that the solid portion of the heat sink has a higher thermal conductivity and a larger heat capacity than the heat-generating electronic component. Continuing to transfer the heat of electronic components to the solid part of the heat sink while this solid part is not thermally saturated with static heat radiation to the surroundings,
It is possible to continue to cool the heat-generating electronic components without forced movement of the air by the fan, and also to cool the heat-generating electronic components sufficiently depending on the heat capacity of the solid parts. Since the sufficient cooling can be achieved with a volume around the bulky area formed by the conventional fins provided to exert a sufficient cooling effect without a fan, the electromagnetic induction heating cooker does not become particularly large. Practicality is not impaired.

When the solid portion of the heat sink is individually made to correspond to a plurality of heat-generating electronic components to perform the cooling, the heat-generating electronic components corresponding to the respective solid portions are accumulated with each other or correspond to each other. Stabilize the cooling performance by preventing the heat capacity of the heat generating electronic parts other than the heat generating electronic parts from inadvertently breaking the relationship of the thermal capacity with the corresponding heat generating electronic parts in each solid part. Can be achieved.

When heat of the heat sink is taken away by the heat radiating plate thermally coupled to the heat sink to radiate the heat to continue the cooling, the heat of the heat sink is taken away by the heat radiating plate, and the solid portion of the heat sink is removed. The required heat capacity or volume is small and the heat sink is heat-coupled with the surrounding air in a wide area without taking up much space due to the spread of the surface in a shape adapted to the surrounding area. Convection and flow due to temperature difference etc. can be freely performed without restraining or staying in place to achieve efficient cooling without a fan, and the miniaturization is promoted by cooling the heat sink, thus reducing the cooling effect. The heat sink can be made smaller and lighter without the overall size becoming larger.

The cooling structure of the electromagnetic induction heating cooker which achieves the above-mentioned method is such that the cooking coil such as a pot or a heating cooker is heated by electromagnetic induction by the work coil to perform heating and cooking. In the cooling structure of the electromagnetic induction heating cooker that cools the heat-generating electronic components in the energization / control circuit with the heat sink, to the heat sink that is thermally coupled to the heat-generating electronic components and has higher thermal conductivity than the heat-generating electronic components,
It suffices that a solid part having a larger heat capacity than the heat-generating electronic component is provided and a heat sink is thermally coupled to this heat sink, and the heat sink is a natural introduction of outside air in the outer case of the rice cooker body. Preferably, it is located in the air passage where natural discharge takes place.

When the heat sink has a structure in which the heat coupling area with the heat radiating plate is larger than the heat coupling area with the heat generating electronic component, the heat sink takes advantage of the size of the heat sink to take the heat taken from the heat generating electronic component. Since the heat-dissipating plate having a larger size than that between the heat-generating electronic components and the heat-dissipating surface can quickly move to the heat-dissipating plate side having high cooling efficiency, the cooling effect of the heat-generating electronic components can be enhanced.

When the volume of the solid portion of the heat sink is equal to or larger than the volume of the corresponding heat-generating electronic component, even if the heat of the total heat capacity of the heat-generating electronic component is received, it does not saturate including static heat radiation to the surroundings. The advantage of being able to continue cooling the heat-generating electronic components for a long time only by static heat transfer is that the remaining surface area of the solid part is larger than the heat-bonding area of the heat-generating electronic parts. The effect of sustaining cooling by heat transfer can be enhanced, and the area of thermal coupling with a heat sink or the like can be further increased.

When the heat sink has a heat capacity or volume that does not cause temperature equilibrium or temperature rise during the heating operation of the cooking process, not only the fan but also the natural convection and flow of air are generated. Since it is possible to continue cooling the heat-generating electronic components throughout the cooking process only by using pure static heat transfer, which is not used, it is easy to guarantee the required cooling performance.

The heat sink in each case is preferably made of an aluminum material for cooling and weight reduction. However, it is not limited to this.

Further, in the structure in which the circuit board having the heat generating electronic component and the heat radiating plate are connected to each other in a substantially L-shape at the heat coupling portion via the heat sink, the heat generating electronic component, the heat sink, and the heat radiation The thermal coupling through the heat sink that moves the heat in the order of the plates to cool the heat-generating electronic components is satisfied by the connection structure in which the circuit board and the heat dissipation plate are substantially L-shaped, and is formed inside the body of the electromagnetic induction heating cooker. The dead space having a substantially L-shaped cross section formed by the bottom portion and the body portion is used to facilitate the placement, and the heat dissipation plate is opened in the body without being covered with the circuit board or approaching in a substantially parallel manner.
The cooling effect is improved because the surrounding air is not restricted and flows easily.

[Brief description of drawings]

FIG. 1 is a sectional view of an electromagnetic induction rice cooker showing one embodiment of the present invention.

FIG. 2 is a plan view of an essential part showing a cooling structure part of the rice cooker of FIG.

3 is a control circuit diagram of the rice cooker of FIG. 1. FIG.

FIG. 4 is a sectional view of an electromagnetic induction rice cooker showing another embodiment of the present invention.

FIG. 5 is a sectional view of an electromagnetic induction rice cooker showing another embodiment of the present invention.

FIG. 6 is a cross-sectional view of the electromagnetic induction rice cooker of FIG. 5 viewed from another direction.

FIG. 7 is a plan view of essential parts showing a cooling structure using a conventional heat sink with fins.

FIG. 8 is a cross-sectional bottom view of an electromagnetic induction rice cooker showing another conventional example.

[Explanation of symbols]

1 body 3 pots 10a, 10b Work coil 14 air passages 143 control board 63 IGBT 64 DB 201 heat sink 201a, 201b Solid part 202 heat sink 203 screws 204 air

Claims (12)

[Claims] 1. An electromagnetic induction heating cooker for cooling a heating device such as a pot or a cooking plate by electromagnetic induction with a work coil to heat the electronic parts in a current-carrying / control circuit of the work coil with a heat sink. In a cooling method for a container, a heat sink that is thermally coupled to a heat-generating electronic component and has a higher thermal conductivity than the heat-generating electronic component is provided with a solid portion having a larger heat capacity than the heat-generating electronic component. An electromagnetic wave characterized by having a higher thermal conductivity and a larger heat capacity than a component so that the heat from the heat-generating electronic component is transferred and cooled while accumulating the heat to maintain the cooling. Cooling method of induction heating cooker. 2. The cooling method for an electromagnetic induction heating cooker according to claim 1, wherein the solid portion is individually cooled to correspond to a plurality of heat-generating electronic components. 3. The cooling of the electromagnetic induction heating cooker according to claim 1, wherein the heat of the heat sink is taken away by a heat radiating plate thermally coupled to the heat sink and the cooling is continued. Method. 4. A cooking device such as a pan or a cooking plate is heated by electromagnetic induction with a work coil for cooking.
In the cooling structure of the electromagnetic induction heating cooker that cools the heat-generating electronic components in the work coil energization / control circuit with the heat sink, the heat generation is performed on the heat sink that is thermally coupled to the heat-generating electronic components and has higher thermal conductivity than the heat-generating electronic components A cooling structure for an electromagnetic induction heating cooker, characterized in that a solid portion having a larger heat capacity than electronic parts is provided and a heat sink is thermally coupled to this heat sink. 5. The cooling structure for an electromagnetic induction heating cooker according to claim 4, wherein the heat radiating plate is located in an air passage through which natural introduction and natural discharge of outside air in the outer case of the rice cooker body is performed. 6. The cooling structure for an electromagnetic induction heating cooker according to claim 4, wherein the heat sink has a larger heat coupling area with the heat radiating plate than a heat coupling area with the heat-generating electronic component. . 7. The cooling structure for an electromagnetic induction heating cooker according to claim 4, wherein the solid portion is provided corresponding to each of the plurality of heat-generating electronic components. 8. The cooling structure for an electromagnetic induction heating cooker according to claim 4, wherein the volume of the solid portion is equal to or larger than the volume of the corresponding heat-generating electronic component. 9. The cooling structure for an electromagnetic induction heating cooker according to claim 4, wherein the remaining surface area of the solid portion is larger than the area of thermal coupling with the heat-generating electronic component. 10. The heat sink according to claim 4, wherein the heat sink has a heat capacity or volume that does not cause temperature equilibrium or temperature rise during the heating operation of the cooking step. Cooling structure of electromagnetic induction heating cooker. 11. The cooling structure for an electromagnetic induction heating cooker according to claim 4, wherein the heat sink is made of an aluminum material. 12. The circuit board having the heat-generating electronic component and the heat dissipation plate are connected to each other in a substantially L-shape at a heat coupling portion via a heat sink. The cooling structure for the electromagnetic induction heating cooker according to 1.