JP2916376B2 - Induction heating pot, method for producing the same, and induction heating cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating pot with improved thermal efficiency, a method of manufacturing the pot, and an induction heating cooker for cooking the pot by generating an induction current with an induction heating coil. About.

[0002]

BACKGROUND ART induction heating cooker, pot used for example induction heating cooker, for example, as shown in FIG. 11, a magnetic stainless steel is an excellent aluminum and magnetic material in thermal conductivity of the flat plate state The clad material is roll-pressed to obtain a clad material, and the resulting clad material is formed by drawing to form a cylindrical container having a magnetic stainless steel disposed outside. Thereby, the pot 1 is formed in a state where the outside is covered by the induction heating unit 2 and the inside is covered by the heat conduction unit 3.

[0003] In the rice cooker main body, two induction heating coils 4 and 5 are provided corresponding to the center and the peripheral portion of the bottom portion of the pot 1, respectively.
5, an induction current is generated in the induction heating portion 2 of the pan 1, and heat is generated by the resistance loss of the induction heating portion 2, and the heat is conducted through the entire heat conduction portion 4 to make the inside of the pan 1. Heat. Therefore, the water and rice stored in the pot 1 are cooked by the heat transmitted from the induction heating unit 2 to the heat conduction unit 3.

[0004]

However, the conventional pot 1 described above has the following disadvantages.
That is, first, the thermal conductivity of the magnetic stainless steel as the induction heating part 2 is 0.062 (cal / cm · sec · ° C.).
On the other hand, since the thermal conductivity of aluminum as the heat conducting part 3 is about 0.53 (cal / cm · sec · ° C.), the induction heating part 2 has a higher thermal conductivity than the heat conducting part 3. The magnitude of the conductivity is extremely low at about 1 / 8.5. Magnetic stainless steel has a specific heat of about 0.59 that of aluminum.
0.85 (cal / ° C. / cm ³ )
・ Large cm ³ ).

For this reason, the induction heating portion 2 made of magnetic stainless steel having a low thermal conductivity does not contribute substantially to the heat transfer to the heat conduction portion 3. Because it covers the whole, the volume of the bottom wall and the wall of the peripheral wall of the induction heating portion 2 becomes considerably large, and the heat capacity becomes considerably large due to the characteristics of the material having a large specific heat, such as rice and water. As a result, a large amount of heat to be given to the pan 1 is deprived of the heat conducting part 3, resulting in a large heat loss when viewed as the whole pot 1, resulting in poor thermal efficiency. Another problem is that the specific gravity of aluminum is 2.7 g / cm ³ , whereas the specific gravity of magnetic stainless steel is 7.7 g / cm ^3, which is 2.85 times that of aluminum. , Which is inconvenient to handle.

Although the induction heating section 2 has no benefit except for the induction heating as described above, since the clad material is used as a material forming the pot 1, the entire pot 1 is surrounded by the induction heating section 2 made of magnetic stainless steel. Configuration, and as a result,
Inevitably, the above-described disadvantages such as a decrease in thermal efficiency and an increase in weight occur.

In order to solve such a problem, it is conceivable that the pot has a configuration in which an induction heating portion made of a magnetic stainless steel is provided only on the outside of the bottom surface of the heat conducting portion. A pan cannot be formed by drawing using a magnetic material of aluminum and stainless steel, and a magnetic stainless steel plate is disposed on the bottom surface of the heat conducting portion to form the heat conducting portion by gravity casting of aluminum. It must be made into a container shape by so-called casting) or die casting.

However, in gravity casting, since the dimensional accuracy is low and the surface of the molded product is rough, it is necessary to cut the entire inner surface after the molding, resulting in a significant increase in cost. On the other hand, die casting can improve the dimensional accuracy than gravity manufacturing, but pressurizes the molten aluminum when pouring it into the mold.
During subsequent solidification of the molten metal, since the gate is narrow and the solidification speed is high, it is difficult to solidify the molten metal in a pressurized state, so that shrinkage cavities that adversely affect strength and thermal conductivity are likely to occur inside.

In order to solve this problem, it is conceivable to form a pot by a molten metal forging method. This molten metal forging method has been developed, for example, for molding an engine piston. By pressing the molten metal received by the lower mold with the upper mold, the molten metal is solidified during the solidification of the molten metal by 300 to 1000 kg.
It is characterized by applying pressure at a high pressure of / cm 2.
Therefore, unlike the die casting, the pot formed by the molten metal forging method has excellent characteristics such as high density, high strength, extremely high dimensional accuracy, and almost no shrinkage porosity.

However, in the molten metal forging method, since the high pressure is applied by the upper mold even during the solidification of the molten metal, the metal undergoes a large thermal shrinkage during the molding, and the metal is tightly attached to the upper mold. For this reason, it is difficult to release the pan from the mold. In particular, when the pot is a deep pan or when the bottom surface is thick, the tendency is remarkable. In this case, when the upper mold is separated from the lower mold by the end of molding, the pot is likely to bite into the upper mold,
It is anticipated that the pot will need to be released by heating and expanding the pot with a burner, making the operation extremely troublesome.

Further, when a flat plate-like magnetic material serving as an induction heating portion is laid under the bottom surface, and then the molten metal is pressed at a high pressure,
There is also a problem that the magnetic plate is deformed by heat and pressure, so that it is not possible to effectively perform induction heating.

In some cases, an iron-based material is adhered to the bottom surface of an aluminum pot by thermal spraying. However, since the portion functioning as the induction heating portion is formed by thermal spraying of the iron-based material, the oxidation is not performed. There is a problem that there are many iron parts, electric conductivity is low and heat generation efficiency is low, and the surface is rough and the appearance is inferior, and other equipment may be damaged, so also magnetic stainless steel and iron-based materials A pot in which an induction heating portion is formed using the above plate material is preferable.

[0013] The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide a heat-efficient, light-weight,
A second object of the present invention is to provide an induction heating pot that can minimize the biting of the mold during forging of the molten metal, can relatively easily release the mold, and can prevent deformation of the induction heating section. A third object of the present invention is to provide a method for producing an induction pot that is dense and free from the possibility of the occurrence of shrinkage cavities. An induction heating cooker is provided.

[0014]

In order to achieve the above-mentioned object, an induction heating pot according to the present invention comprises an induction heating portion formed of a magnetic material in a container shape, and an induction heating portion formed by molten forging. The induction heating portion and its inner surface so as to cover the inner surface
And a pot main part made of a heat conductive material and having a peripheral wall part extending above the upper end part of the induction heating part.

According to the method of manufacturing an induction heating pan of the present invention, there is provided a step of setting an induction heating portion formed of a magnetic material in a container shape in a lower mold, and a step of setting the induction heating portion set in the lower mold. Forming the molten metal between the lower mold and the upper mold by injecting the molten metal of the thermally conductive material and lowering the upper mold relative to the lower mold to press the molten metal in the induction heating section; Filling the filled cavity to cover the inner surface of the induction heating portion and forming a pot main portion whose peripheral wall extends upward from the upper end of the induction heating portion, and solidifying the molten metal under pressure. And taking out the induction heating pot in which the upper mold is raised and the induction heating section and the pot main part are fixedly integrated over the entire inner surface of the induction heating section .

In this method of manufacturing a pot for induction heating, the amount of molten metal injected into the induction heating section may be such that the level of the molten metal reaches substantially the upper end of the induction heating section. In this case, it is preferable to provide a basin for continuously storing the excess molten metal in the cavity.

The amount of molten metal injected into the induction heating portion is
The level of the molten metal is set lower than the upper end of the induction heating part,
While the upper mold enters the molten metal and descends to the lowest position,
It is possible to adopt a configuration in which there is a time zone in which the upper end of the induction heating portion is immersed in the molten metal stored therein.

In this case, in order to secure a time zone in which the upper end of the induction heating section is immersed in the molten metal stored therein, the upper mold is immersed in the molten metal and descends, so that the molten metal is moved to the upper end of the induction heating section. By suspending once at the time of immersion, the time zone in which the upper end of the induction heating portion is immersed in the molten metal stored therein can be secured, and thereafter, it can be configured to continuously descend to the lowest position.

The upper mold descends at a low speed from the start of infiltration into the molten metal to the lowermost position, so that the molten metal stored in the induction heating portion has a time zone in which the upper end of the induction heating portion is immersed. It is also possible to adopt a configuration that is secured.

Further, in the method for producing the induction heating pot of the present invention, there may be a step of heating the induction heating portion before setting the induction heating portion in the lower mold. Before setting in the lower mold, there may be a step of fixing a bonding layer made of the same material as the molten metal to the inner surface of the induction heating portion.

In the method of manufacturing an induction heating pot according to the present invention, the portion of the lower mold for forming the peripheral wall portion of the main portion of the pot is expanded, and induction heat is generated at the inner peripheral edge of the step portion generated by the expansion. The lower part of the induction heating part is supported by the lower part of the upper end, and the lower part of the induction heating part is raised from the inner surface of the lower mold. The upper part can be configured so as to be present in the cavity in a non-contact state with the lower mold and the upper mold when it is lowered vertically.

In the induction heating cooker of the present invention, the induction heating section formed of a magnetic material in a container shape is formed by forging molten metal.
So that the entire inner surface of the induction heating portion is
An induction heating pot provided with a pot main part made of a heat conductive material having a peripheral wall portion extending upward from the upper end of the induction heating portion and being fixedly integrated over the region ; An induction heating coil arranged at a position corresponding to the bottom of the pan,
Control means for controlling the supply of high-frequency power to the induction heating coil.

[0023]

In the induction heating pot of the present invention, since the induction heating portion is provided only on the outside of the bottom and lower portions of the whole, the volume of the meat portion is small, the heat capacity is reduced, and the weight is reduced. Is done. Also, when the main part of the pot is formed by melt forging, the pot-shaped induction heating part receives a force that tends to decrease inward due to shrinkage during solidification, thereby preventing the main part of the pot from biting into the mold. since nor induction heating unit itself is deformed, a high not <br/> stuff the finished dimensional accuracy.

In the method of manufacturing a pot for induction heating according to the present invention, when the molten metal is poured into the induction heating portion in a container shape, the molten metal is diffused and bonded to the induction heating portion and solidified to form a main portion of the pot. At this time, it is fixed and integrated with the induction heating part. The main part of the pot is formed by solidifying the molten metal under pressure.

When the molten metal is injected until the molten metal surface reaches the substantially upper end of the induction heating portion, the molten metal diffuses over the entire inner surface of the induction heating portion. When the molten metal is poured almost to the upper end of the induction heating section, the amount of the molten metal may be larger than the volume of the main part of the pot. Can be stored in

When the amount of the molten metal to be injected into the induction heating portion is determined so that the surface of the molten metal is lower than the upper end of the induction heating portion, the molten metal is exposed at the upper end portion of the induction heating portion exposed from the molten metal surface. As the upper die enters the molten metal and descends to the lowest position, there is a time zone in which the molten metal is immersed in the molten metal up to the upper end of the induction heating section. It can be diffusion-bonded to the inner surface of the portion almost completely.

If the upper mold is temporarily stopped by assuring the time period during which the molten metal is immersed in the molten metal up to the upper end of the induction heating section, the lower mold can be lowered at a rapid speed thereafter. It will be shortened. In addition, when the time zone is secured by lowering the lower die at a low speed, the control of the movement and stop of the upper die is simplified, unlike the temporary stop method of the upper die.

If the induction heating section is heated before the induction heating section is set in the lower mold, the temperature can be prevented from lowering when the molten metal is poured, and excellent diffusion can be performed. . Further, if the bonding layer made of the same material as the molten metal is fixed to the inner surface of the induction heating portion before setting the induction heating portion to the lower mold, the diffusion bonding between the molten metal and the induction heating portion is further ensured. Can be performed.

The lower part of the upper end of the induction heating part is supported by the inner peripheral edge of the step formed in the lower die, and the lower part than the supported part is raised from the inner surface of the lower die. When the upper mold is lowered relative to the lower mold and the upper part is present in the cavity in a non-contact state with the lower mold and the upper mold, the upper mold When the molten metal is pressurized due to the lowering, the inner peripheral edge of the step portion is sealed, so that the molten metal does not flow to the lower surface side of the induction heating portion. In addition, since the upper end portion of the induction heating portion is embedded in the main portion of the pot, it is difficult to peel off and the appearance is improved.

In the induction heating cooker of the present invention, cooking is performed by induction heating using an induction heating pot in which an induction heating portion is provided only in the lower portion of the main portion made of a heat conductive material.
Good thermal efficiency.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment in which the present invention is applied to an induction heating type rice cooker will be described with reference to FIGS. In FIG. 4 showing the entire configuration of the rice cooker, a resin rice cooker main body 11 is shown.
A lid 12 is provided at the upper part of the upper part so as to be openable and closable up and down by a hinge 13. Inside the rice cooker main body 11, there is provided an outer tank portion 15 capable of accommodating the induction heating pot 14, and an induction heating coil 16 is provided immediately below the bottom surface of the outer tank portion 15.
Is provided, and a ferrite 17 for forming a magnetic circuit is provided underneath. In addition, pot 1 for induction heating
4 is simply referred to as a pot 14 below. When the lid 12 is closed, the upper opening of the pot 14 housed in the outer tank 15 is closed by an inner lid 12 a provided below the lid 12. Is inner lid 1
Lid heater 18 for heating the inside of the pot 14 via the 2a
Are arranged.

In the center of the bottom of the outer tub 15, a pan 14
A temperature sensor 19 is provided so as to come into contact with the bottom surface of the pan 14 so as to detect the temperature of the pan 14. In addition, an inverter circuit section 20 for generating a high-frequency current and a cooling fan 21 are provided on the inner bottom of the rice cooker main body 11. A control circuit section 22 as a control means and an operation section 2 are provided on the front side in the rice cooker main body 11.
3 are provided. The operation unit 23 is provided with operation switches and a display so as to be exposed outside the front surface of the rice cooker main body 11. A body heater 24 for heating and keeping the pot 14 warm is provided inside the rice cooker main body 11 via a side wall of the outer tub 15.

Next, the configurations of the pot 14 and the induction heating coil 16 will be described in detail with reference to FIG. The pot 14 includes an induction heating section 25 and a pot main section 26. The induction heating section 25 is formed of a magnetic material such as a magnetic stainless steel or a steel plate, in this embodiment, a magnetic stainless steel that does not require rust prevention treatment, and is formed in a container having a relatively shallow bottom. Of the surface layer. On the other hand, pan main part 26
For example, a heat conductive material such as aluminum or an aluminum alloy, which is formed into a relatively deep bottom container by a melt forging method described later using aluminum in this embodiment, and a lower outer surface covers an inner surface of the induction heating portion 25. So that the induction heating section
25 and the entire inner surface thereof .
The pot main part 26 has a deeper shape than the induction heating part 25, and its peripheral wall is formed to extend above the induction heating part 25.

Here, the height of the induction heating section 25 is set to be higher than the upper end of the opposed induction heating coil 16 by the dimension Δh. This dimension Δh is set as a dimension slightly larger than the gap dimension g of the space G between the pot 14 and the induction heating coil 16. The reason why the height of the induction heating portion 25 of the pan 14 is set as described above is that even if a magnetic material is provided above the induction heating portion 25, it does not contribute to the induction heat generation and the expensive magnetic material is expensive. This is to reduce the amount of stainless steel used and to reduce the overall weight. Such a configuration cannot be realized by using a conventional clad material.

FIG. 5 shows an electrical configuration. The control circuit section 22 as a control means includes a control circuit such as a microcomputer, in which a control program for rice cooking is stored in advance. I have. This control circuit unit 2
Reference numeral 2 is connected to receive an operation signal from the operation unit 23, and when the control program is executed, outputs a control signal to the inverter circuit unit 20 according to the operation signal from the operation unit 23. The inverter circuit section 20 supplies a high-frequency current having a predetermined frequency to the induction heating coil 16 in accordance with the supplied control signal, and causes the pan 14 to perform a heating operation.

The output terminal of the temperature sensor 19 is
3 and is connected to the control circuit unit 22 to supply a temperature detection signal of the pan 14 to the control circuit unit 22. The cooling fan 21, the lid heater 18, and the body heater 24 are each controlled to be energized by a drive control signal provided from the control circuit unit 22.

Now, a method of manufacturing the pot 14 by melt forging will be described. First, FIG. 2 shows a mold used for manufacturing the pot 14, and in FIG.
Is formed in the lower mold 27 having a shape matching the outer shape of the pot 14, and the upper mold 29 forming the male mold (pressing mold) is formed in a shape matching the inner shape of the pot 14. . Of the two molds 27 and 29, the lower mold 27 is fixed,
The upper mold 29 is moved up and down by a hydraulic cylinder (not shown). In order to push the pot 14 out of the lower mold 27 after the molding, the lower mold 27 is provided with an ejector pin 30 so as to be vertically movable.

When the upper mold 29 descends to the lowermost position, as shown in FIG.
A cavity C for molding the pot main portion 26 is formed. At this time, the large-diameter seal portion 29a formed on the upper portion of the upper mold 29 fits tightly with the seal portion 26a formed on the upper portion of the lower mold 26, whereby the inside of the cavity C is sealed and the height of the molten metal increases. It is configured to apply pressure.

In order to manufacture the pot 14 using the mold having the above structure, the upper mold 29 is raised to the uppermost position, as shown in FIG. The bottom container-shaped induction heating section 25 is shown in FIG.
The lower mold 27 is set to be in contact with the bottom in the recess 28 as shown in FIG. Next, a predetermined amount of molten aluminum H is injected into the induction heating section 25 as shown in FIG.

At this time, the injection amount of the molten metal H is
Are defined to be equal to the volume of the bottom wall portion, the peripheral wall portion, and the flesh portion of the upper end flange portion 26a. In this case, the induction heating section 2
5 is larger than the injection amount of the molten metal H,
Accordingly, the surface of the poured molten metal H is lower than the upper end of the induction heating section 25 by the dimension indicated by L in FIG. Since the molten metal H is at a high temperature, the molten metal H starts to diffuse into the inner surface layer of the induction heating section 26 under the high temperature condition. At this time, the inner surface of the upper end portion exposed from the molten metal H is excluded from the diffusion.

After the injection of the molten metal H, the lowering of the upper mold 29 is started.
The level of the molten metal H gradually rises with the decrease of the temperature. Then, as shown in FIG. 3 (d), when the molten metal surface reaches the upper end of the induction heating portion 26, the upper mold 29 temporarily stops, and at this stop, the molten metal H is discharged from the inner surface of the induction heating portion 26. The part exposed from the surface of the molten metal at the time of injection is soaked and diffused into the part.

Thereafter, as shown in FIG.
9 descends rapidly to the lowermost position, whereby the molten metal H is pressurized and filled into the cavity C formed between the lower mold 27 and the upper mold 29. Then, the state where the molten metal H is pressurized to a high pressure is maintained as it is, during which the molten metal H solidifies and is formed as a pot main part 26 fixedly integrated with the induction heating part 25 by diffusion. During this solidification, the molten metal H contracts, but the peripheral wall of the induction heating portion 25 made of magnetic stainless steel prevents the molten metal H (the main pot portion 26) from being tightly fixed to the upper mold 29 as much as possible. Thereafter, as shown in FIG.
The upper mold 29 rises to the original uppermost position while leaving the pot 14 in the lower mold 27. Next, as shown in FIG. 3 (g), the eject pin 30 rises and pushes the pot 14 out of the lower mold 27. Thus, the forming of the pan 14 is completed.

Next, the operation when rice is cooked using the pot 14 molded as described above will be described. When rice and water are stored in the pot 14 and a rice cooking start operation is performed by the operation unit 23, the control circuit unit 22 executes a rice cooking program to start a rice cooking operation, and outputs a control signal. Inverter circuit 2
When the control signal is output from the control circuit unit 22, a high frequency current of 0 is supplied to the induction heating coil 16 at a predetermined frequency.

As a result, the magnetic flux generated around the induction heating coil 16 passes through the gap G with the pot 14, the inside of the induction heating section 25, the gap G with the pot 14, and the ferrite 17. become. At this time, the position of the upper end of the induction heating unit 25 is a distance Δ from the position of the upper end of the induction heating coil 16.
h, so that the magnetic flux is prevented from passing through the pot main part 26 and the impedance of the induction heating coil 16 is reduced, and the heat generation operation in the induction heating part 25 is performed efficiently. ing.

Then, in the surface layer of the induction heating section 25, an induction current is generated due to the change of the magnetic flux Φ, and heat is generated due to the resistance loss. Since the magnetic material (magnetic stainless steel) constituting the induction heating section 25 has a low thermal conductivity, heat generated in a portion of the induction heating section 25 that performs a heating operation waits for conduction to the entire induction heating section 25. Soon,
The heat is transmitted from the heat-generating portion to the pan main portion 26, and the pan main portion 2
In 6, the heat is conducted to the entire bottom portion and the entire peripheral wall portion, and heats water and rice in the pot 14.

The rice cooking proceeds by such heating, and the control circuit 22 performs a control operation according to the temperature detected by the temperature sensor 19, and outputs a stop signal to the inverter circuit 20 when the rice cooking is completed, and the induction heating coil 16. The supply of high frequency current to is stopped. Thereafter, the control circuit unit 22 operates the lid heater 1
8. The body heater 24 is energized to start a warming operation for keeping the cooked rice warm.

As described above, according to the present embodiment, the induction heating portion 25 is provided only outside the lower portion of the entire pot 14, so that the portion that generates heat by the induction action occupies most of the portion. The required minimum shallow depth can be obtained. And even if the induction heating part 25 is made to have such a shallow bottom, the heat generated in the heating operation part is lower than that of the conventional pot formed at the deep bottom because the thermal conductivity is low due to the characteristics of the material. The function of transmitting to the pot main part 26 is not reduced, and conversely, the volume of meat on the peripheral wall of the induction heating part 25 is reduced, so that the heat capacity is reduced and the amount of heat for heating rice and water is large, As the thermal efficiency increases, the weight of the entire pot 14 is reduced. A rice cooker that cooks rice using such a pot 14 has high thermal efficiency.

In addition, when the pot main part 26 is formed by melt forging, when the molten metal H contracts under pressure, the pot main part 26 is strongly fastened to the upper mold 29 by the peripheral wall of the induction heating part 25 having a container shape. This prevents the induction heating section 25 itself from being deformed under a high temperature and a high pressure unlike a flat plate. Therefore, when the upper die 29 is raised after molding, or until the lower mold pan main portion 26 is fixed to the upper die 29 27
After that, it is not necessary to perform the troublesome work of heating the pan main part 26 by the burner and extracting it from the upper mold 29 after that.

On the other hand, in the present embodiment, since the pot main portion 26 is formed by melt forging, the molten metal H is solidified in a state of being pressurized at a high pressure and is formed as the pot main portion 26.
For this reason, the pot main part 26 is dense, has almost no occurrence of shrinkage cavities, is excellent in heat conductivity, and has excellent strength and dimensional accuracy, and is excellent in appearance without roughness on the surface. .

Since the induction heating section 25 is formed in a container shape, the molten metal H can be injected into the inside and stored therein, so that the molten metal can be prevented from adhering to the outer surface of the induction heating section 25. Therefore, unlike the case where the induction heating portion is formed in a flat shape, when the molten metal injected into the lower mold wraps around the lower side of the flat induction heating portion and is formed as a pan, aluminum is outside the induction heating portion. It is possible to effectively prevent the occurrence of a problem that the toner adheres to the bottom surface, impairs the appearance, and does not efficiently generate heat.

The induction heating part 25 and the pot main part 26 are fixed by diffusion by injecting the molten metal H into the induction heating part 25.
No special device is required for fixing the hologram. By the way, when the injection amount of the molten metal H is set to be equal to the volume of the meat of the main pot portion 26, the thickness of the main pot portion 26 is not so large. Less than. For this reason, the surface of the molten metal H is lower than the upper end of the induction heating section 25, and the molten metal H does not diffuse to the portion of the inner surface of the induction heating section 25 that is exposed from the molten metal surface.

In this regard, in this embodiment, the upper mold 29
Penetrates into the molten metal H, so that the surface of the molten metal
At the time when the upper end of the upper mold 29 is stopped,
Since the time zone in which the molten metal H immerses the inner surface of the induction heating section 25 to the upper end is ensured, when the molten metal H is diffused over the entire inner surface of the induction heating section 25 and molded as the pot main section 26. Thus, the fixation between the induction heating portion 25 and the pot main portion 26 is ensured.

By the way, even if the upper mold 29 is lowered from the uppermost position to the lowermost position at a stretch, the upper end of the induction heating portion 25 can be immersed in the molten metal H. In this case, the molten metal H The solidification is started immediately after being extruded into the entire cavity C, and the temperature is lowered. Therefore, it is impossible to guarantee sufficient diffusion at a high temperature. However, in the present embodiment, the molten metal H is stored in the induction heating part 25, and a time period in which sufficient heat can be given to the upper end portion of the induction heating part 25 can be secured. Is sufficiently diffused to the upper end.

Then, the fusing surface f is thus set to the induction heating portion 2.
In order to secure a time zone in which the molten metal H is immersed in the entire surface of the induction heating section 25 by raising the molten metal H to the upper end of the induction heating section 25, the lowering of the upper mold 29 is temporarily stopped halfway. Since the entire inner surface can be kept immersed for a certain period of time, the upper mold 29 can be immediately lowered to the lowermost position, and the time required for the entire molding can be reduced.

As another means for securing a time zone in which the molten metal H stored in the induction heating section 25 immerses the entire inner surface of the induction heating section 25, the upper mold 29 is gradually moved from the uppermost position to the lowermost position. May be lowered. Even with this configuration, the molten metal H gradually overflows from the induction heating portion 25 into the cavity C after immersing the inner surface of the induction heating portion 25 to the upper end surface, but the entire inner surface of the induction heating portion 25 is molten. Since the time zone of immersion in H can be secured, the diffusion of the molten metal H is performed favorably. Further, when the lowering of the upper mold 29 is temporarily stopped, the position control for the halfway stop must be performed. However, when the upper mold 29 is gradually lowered, the upper mold 29 is moved to the lowermost position. Since only lowering to the position is sufficient, the position control configuration of the upper mold 29 is simplified.

FIGS. 6 and 7 show a second embodiment of the present invention. The same parts as those in FIG. 2 are denoted by the same reference numerals and different parts will be described. The inner diameter of the seal portion 27a of the lower mold 27 is enlarged from a position slightly above the portion where the flange 26a is formed, and the outer diameter of the seal portion 29a of the upper mold 29 is also increased according to the inner diameter of the seal portion 27a of the lower mold 27. Have been. The upper die 29 has a smaller diameter than the seal portion 29a between the seal portion 29a, the peripheral wall of the pot main portion 26, and the portion of the flange 26a that forms the corner of Sakai. When lowered to the lower position, the pool portion 31 is formed between the outer peripheral surface of the small diameter portion 29b below the seal portion 29a of the upper die 29 and the lower inner peripheral surface of the seal portion 27a of the lower die 27. It is configured to be formed.

On the other hand, in this embodiment, the injection amount of the molten metal H is set to be equal to the internal volume of the induction heating section 25. And
The internal volume of the pool portion 31 is set to be equal to the amount obtained by subtracting the volume of the meat of the bottom wall portion and the peripheral wall portion of the pot main portion 26 from the injection amount of the molten metal H.

In order to form the pot 14 in the above configuration, first, the induction heating section 25 is set in the lower mold 27, and then the molten metal H is injected into the induction heating section 25. At this time, since the injection amount of the molten metal H is determined to be equal to the internal volume of the induction heating section 25, as shown in FIG.
5 is almost the same as the upper end. For this reason, the molten metal H diffuses over the entire inner surface of the induction heating portion 25.

After the injection of the molten metal H, the upper mold 29 is immediately lowered to the lowest position at a rapid speed. Thereby, the molten metal H
Is pressurized and filled into the cavity C as shown in FIG. 7, and excess molten metal is stored in the pool 31. The molten metal H solidifies under this pressure, and the pot main part 26 integrated with the induction heating part 25 is formed.

After this molding, the upper mold 29 is raised and the pan 14
From the lower mold 27 from the ejector pin 30. Thereafter, the excess aluminum solidified in the basin 31 is removed as shown in FIG.
Is cut and removed at a position indicated by a two-dot chain line M to obtain a pot 14.

As described above, in the present embodiment, the injection amount of the molten metal H is determined to be equal to the internal volume of the induction heating section 25,
Is diffused from the beginning of the injection to the entire inner surface of the induction heating portion 25. For this reason, it is not necessary to temporarily stop the lowering during the lowering of the upper mold 29 or to gradually lower the upper mold 29 from the beginning, and it is possible to reduce the time required for forming the pan main part 26. In addition, since the basin 31 is provided above the flange 26a, the work of removing the aluminum solidified in the basin 31 becomes easier as compared with the case where the basin 31 is provided in the middle of the peripheral wall of the pan main portion 26.

FIGS. 8 and 9 show a third embodiment of the present invention. The same parts as those in FIG. 2 are denoted by the same reference numerals and different parts will be described. As shown in FIG. 8, the upper end portion of the peripheral wall portion of the induction heating portion 25 is provided with a slanting upwardly inclined portion 25a. On the other hand, the inner diameter of a portion of the lower mold 27 that forms a peripheral wall projecting upward from the induction heating portion 25 of the pot main portion 26 is enlarged. And the induction heating part 25 is the inclined part 2
The portion directly below 5a is configured to be supported by the inner peripheral edge 27c of the step 27b generated by enlarging the inner diameter of the lower mold 27. At this time, the outer surface of the induction heating portion 25 is in a state of being raised from the inner surface of the lower mold 27, and
Is lowered to the lowest position, the inclined portion 25a
It is configured to be in a non-contact state with both the 7 and the upper mold 29.

In the above configuration, in order to form the pot main portion 26, the induction heating portion 25 is supported in the lower mold 27 by a slightly lower peripheral portion of the inclined portion 25a by the inner peripheral edge 27c of the step portion 27b. Set as shown. In this state, as shown in FIG. 8, the molten metal H is injected by an amount such that the surface of the molten metal is slightly lower than the upper end of the induction heating portion 25.

Thereafter, the upper mold 29 is lowered, and when the surface of the molten metal H reaches the upper end of the induction heating section 25, the lowering of the upper mold 29 is temporarily stopped, and the molten metal H is entirely removed from the inner surface of the induction heating section 25. The time zone to spread to is secured. After this, FIG.
As shown in (2), the upper mold 29 is lowered to the lowest position at a rapid speed. At this time, the molten metal H is pressurized by the upper mold 29, and the induction heating portion 25 is pressed against the inner peripheral edge 27c of the step portion 27b by the pressure of the molten metal H. Thus, the induction heating section 25
And the inner peripheral edge of the step 27b is sealed, so that the molten metal H leaks below the step 27b on the assumption that the molten metal H overflows from the induction heating portion 25 and fills the cavity C. Will not enter.

For this reason, when molded as a pan 14,
There is no possibility that aluminum may be attached to the outer surface of the induction heating unit 25. The induction heating section 25 is finally formed so as to be in close contact with the inner surface of the lower mold 27 by the pressing force of the molten metal H.

The upper end inclined portion 25b of the induction heating portion 25
Is buried in the molten metal H filled in the cavity C, so that when formed as the pot 14, the inclined portion 25b is embedded in the pot main portion 26 so as not to be seen from the outside. The appearance is improved because it is concealed. Further, it is possible to more reliably prevent the induction heating portion 25 from peeling off from the upper end.

FIG. 10 shows a fourth embodiment of the present invention relating to a method of manufacturing the pot 14. The difference from the first embodiment is that before the induction heating section 25 is set in the lower mold 27, As shown in FIG. 10A, a molten metal J of the same material (aluminum) as the molten metal H is injected into the induction heating portion 25, and thereafter,
As shown in FIG. 10 (b), a step (pretreatment step) of discarding the molten metal J is provided. By this step, the fixed layer 32 of the same material as the molten metal H is fixed to the entire inner surface of the induction heating section 25 by diffusion. At the same time, since the induction heating section 25 is heated by the molten aluminum, when the induction heating section 25 is set in the lower mold 27 and the molten metal H is injected, the molten metal H is hardly cooled, and is diffused to the induction heating section 25. Is performed more reliably, and the fluidity of the molten metal H is ensured, so that the molten metal H has excellent run-out into the cavity C.

The present invention is not limited to the embodiment described above and shown in the drawings, but can be modified or expanded as follows. The induction heating cooker is not limited to a rice cooker, and is referred to as an electromagnetic cooker having a configuration in which a pot is placed on a flat top plate, and the pot is induced to generate heat by an induction heating coil arranged below the top plate. The pot is not limited to a rice cooker, and may be a pot for an electromagnetic cooker. The main part of the pot may be made of aluminum alloy, copper, copper alloy or the like.

[0069]

According to the first aspect of the present invention, since the induction heating portion is provided only on the bottom and outside the lower portion of the whole, the volume of the meat portion of the induction heating portion is small and the weight is reduced. And the thermal efficiency is improved.
In addition, when the main part of the pot is formed by forging the molten metal, it is possible to prevent the pot-shaped induction heating part from receiving a force that causes the main part of the pan to decrease inward during solidification of the molten metal, thereby preventing the pot from being strongly tightened to the mold. Since the induction heating portion is not deformed, the finished dimensional accuracy is high.

In the method for manufacturing an induction heating pot according to the second aspect, the induction heating section and the pot main section are fixedly integrated by diffusion when the molten metal is poured into the container-shaped induction heating section. It is possible to eliminate the need for a step for conversion. The main part of the pot is formed by a high-pressure casting method that solidifies the molten metal under pressure, so it is dense, has high strength, has extremely high dimensional accuracy, has almost no shrinkage cavities, and has a beautiful surface. Becomes In addition, since the main part of the pot does not bite into the male mold due to heat shrinkage during solidification, there is no need to heat the mold with a burner or the like when releasing the mold.

In the method for manufacturing an induction heating pot according to the third aspect, the molten metal is diffused and bonded to substantially the entire inner surface of the induction heating section by injecting the molten metal until reaching the upper end of the induction heating section. . According to the method of manufacturing a pot for induction heating according to the fourth aspect, excess molten metal larger than the volume of the meat portion of the main portion of the pot can be stored in the pool. In the method for producing an induction heating pot according to claim 5, even when the molten metal surface is below the upper end of the induction heating portion, the upper mold enters the molten metal and descends to the lowest position. On the way, there is a time zone in which the molten metal is immersed in the molten metal up to the upper end of the induction heating section, so that the molten metal can be diffusion-bonded to substantially the entire inner surface of the induction heating section.

In the method for manufacturing the induction heating pot according to the sixth aspect, the lower mold can be lowered at a rapid speed after being immersed in the molten metal up to the upper end of the induction heating section, so that the time is shortened. In the method for manufacturing the induction heating pan according to claim 7, since the lower mold is lowered at a low speed so that the upper end of the induction heating unit is immersed in the molten metal, unlike the temporary stop method of the upper mold, the movement of the upper mold, Stop control is simplified.

In the method of manufacturing an induction heating pot according to the present invention, since the induction heating portion is preheated, when the molten metal is poured, the temperature can be prevented from lowering, and excellent diffusion can be performed. In the method for manufacturing an induction heating pot according to claim 9, the bonding layer made of the same material as the molten metal is fixed to the inner surface of the induction heating portion before the induction heating portion is set in the lower mold. Diffusion bonding can be performed even better.

In the method of manufacturing a pot for induction heating cooking according to the tenth aspect, when the molten metal is pressurized by lowering the upper mold, the molten metal does not flow to the lower surface side of the induction heating portion. In addition, since the upper end portion of the induction heating portion is embedded in the main portion of the pot, it is difficult to peel off and the appearance is improved. In the induction heating cooker according to the eleventh aspect, since cooking is performed by induction heating using an induction heating pot in which an induction heating portion is provided only in a lower portion of a main portion made of a heat conductive material, heat efficiency is improved. Is good.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a pot and an induction heating coil portion showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a mold configuration for melt forging.

FIG. 3 is a longitudinal sectional view showing a pot manufacturing process in order.

FIG. 4 is a longitudinal side view of a rice cooker.

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

FIG. 6 is a longitudinal sectional side view showing a second embodiment of the present invention in a state when molten metal is poured;

FIG. 7 is a longitudinal sectional side view showing a solidified state of a molten metal.

FIG. 8 is a view corresponding to FIG. 6, showing a third embodiment of the present invention.

FIG. 9 is a diagram corresponding to FIG. 8;

FIG. 10 is a schematic diagram of a preliminary process showing a fourth embodiment of the present invention.

FIG. 11 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

11 is a rice cooker main body, 14 is an induction heating pot, 16 is an induction heating coil, 20 is an inverter control unit, 21 is a control circuit unit (control means), 25 is an induction heating unit, 26 is a pot main unit, 27
Denotes a lower mold, 29 denotes an upper mold, and 31 denotes a basin.

Claims (11)

(57) [Claims] 1. An induction heating portion formed of a magnetic material in a container shape, and formed by molten metal forging and fixedly integrated with the induction heating portion so as to cover the inner surface of the induction heating portion over the entire inner surface thereof . A pot for induction heating, comprising: a pot main portion made of a heat conductive material having a peripheral wall portion extending upward from an upper end portion of the induction heating portion. 2. A step of setting an induction heating portion formed of a magnetic material in a container shape in a lower mold, and a step of injecting a molten metal of a thermally conductive material into the induction heating portion set in the lower mold. By lowering the upper mold relative to the lower mold and pressurizing the molten metal in the induction heating section, the molten metal is filled into a cavity formed between the lower mold and the upper mold, and the induced heat is generated. Forming a pot main part that covers the inner surface of the part and the peripheral wall part extends upward from the upper end part of the induction heating part; a step of solidifying the molten metal in a pressurized state; Induction heating part and main part of pot are induction
Taking out the induction heating pot fixed and integrated over the entire inner surface of the heat generating portion . 3. The method for producing a pot for induction heating according to claim 2, wherein the amount of the molten metal injected into the induction heating section is an amount such that the surface of the molten metal reaches a substantially upper end of the induction heating section. 4. The method for producing an induction heating pot according to claim 3, wherein a basin for continuously storing excess molten metal is provided in the cavity. 5. The amount of molten metal to be injected into the induction heating section is determined such that its surface is lower than the upper end of the induction heating section.
While the upper mold enters the molten metal and descends to the lowest position,
3. The method for producing an induction heating pot according to claim 2, wherein there is a time zone in which the upper end of the induction heating section is immersed in the molten metal stored therein. 6. In order to secure a time zone in which the upper end of the induction heating section is immersed in the molten metal stored therein, the upper mold is penetrated into the molten metal and descends so that the upper end of the induction heating section raises the upper end of the induction heating section. 6. The method for producing an induction heating pot according to claim 5, wherein the method stops once at the time of immersion, and then continuously descends to a lowermost position. 7. The upper mold descends at a low speed from the start of infiltration into the molten metal to a lowermost position, so that the molten metal stored in the induction heating part has a time zone in which the upper end of the induction heating part is immersed. The method for producing a pot for induction heating according to claim 5, wherein the temperature is secured. 8. Before setting the induction heating portion in the lower mold,
The method for producing an induction heating pot according to any one of claims 2 to 7, further comprising a step of heating the induction heating portion. 9. Before setting the induction heating portion in the lower mold,
9. The method according to claim 2, further comprising the step of fixing a bonding layer of the same material as the molten metal to the inner surface of the induction heating portion. 10. A portion of the lower mold for forming the peripheral wall portion of the pan main portion is expanded in diameter, and the induction heating portion is supported at a lower portion of the upper end by an inner peripheral edge of the step portion generated by the diameter expansion. The induction heating part is in a state where the lower part than the part supported by the inner peripheral edge of the step is raised from the inner surface of the lower mold, and when the upper mold is lowered relatively to the lower mold, the upper part is 10. The apparatus according to claim 2, wherein the lower mold and the upper mold are configured to exist in the cavity in a non-contact state.
The method for producing the induction heating pot according to any one of the above. 11. An induction heating portion formed of a magnetic material in a container shape, which is formed by melt forging and is fixed and integrated over the entire inner surface of the induction heating portion so as to cover the inner surface of the induction heating portion. Sa
An induction heating pot provided with a pot main part made of a heat conductive material having a peripheral wall portion extending upward from an upper end of the induction heating section, and a position corresponding to a bottom portion of the induction heating pot An induction heating cooker comprising: an induction heating coil arranged in a heating device; and control means for controlling supply of high-frequency power to the induction heating coil.