TW201922155A - Heating cooking appliance - Google Patents

Abstract

The present invention provides a heating cooker, which can efficiently heat inner sidewall of the heating cooker. The heating cooker is shaped as a cylinder having a bottom, and has in the interior a double-layer wall structure having enclosed space, characterized in that, the heating cooker includes: an internal container of a cylindrical shape having a bottom, which constitutes an internal portion of the heating cooker; an external container of a cylindrical shape having a bottom, which constitutes an external portion of the heating cooker; and working liquid, which is injected into the enclosed space, the amount of the working liquid in the enclosed space is set as an amount not covering the entire bottom surface of the enclosed space.

Description

Heating cooker

The invention relates to a heating cooker.

Patent Document 1 listed below discloses a heating tube type heating cooker. This heating cooker exhibits a double-wall structure having a closed space inside, and a working fluid is injected into the sealed space. Further, when the bottom of the heating cooker is heated, the working fluid boils, and in the working fluid, the vaporized vapor rises along the side of the sealed space. Thereby, the side wall of the inner side of the heating cooker is heated by steam. Further, the vapor of the side wall is heated and condensed to become a liquid as a working liquid. The working fluid that has become a liquid descends by its own weight and returns to the bottom of the closed space. Further, the heating cooker is heated by repeating the above-described phase change cycle of the working fluid.

Prior art literature

Reference Patent Document 1: Japanese Patent No. 2713008

In view of this, our inventors have devote themselves to further research and have initiated research and development and improvement, with a better design to solve the above problems, and have been experimentally and modified to have the present invention.

Problem to be solved by the invention

However, in the above-described heating cooker, there is still room for improvement in the following aspects. In other words, in the above-described heating cooker, the amount of the working fluid in the sealed space for efficiently heating the side wall of the inside of the heating cooker is not defined.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a heating cooker capable of efficiently heating a side wall of an inner side of a heating cooker.

Technical solution for solving the problem

Aspect 1: One or more embodiments of the present invention provide a heating cooker which is formed in a bottomed cylindrical shape and has a double-wall structure having a closed space inside, and is characterized in that it has a bottomed cylindrical inner side. a container constituting an inner portion of the heating cooker; a bottomed cylindrical outer container constituting an outer portion of the heating cooker; and a working fluid injected into the sealed space, the closed space The amount of the working fluid in the inside is set to an amount that does not cover the entire bottom surface of the sealed space.

Morphology 2: One or more embodiments of the present invention provide a heating cooker characterized in that the volume ratio of the working liquid phase to the bottom portion of the sealed space is set to 4 vol% to 80 vol%.

Aspect 3: One or more embodiments of the present invention provide a heating cooker characterized in that, in a longitudinal section, a height dimension of the closed space of a bottom portion of the heating cooker is set to the heating cooking The closed space of the side portion of the device has a width dimension or more and is set to 2 mm or more.

Form 4: One or more embodiments of the present invention provide a heating cooker characterized in that a negative pressure or a vacuum of 0.01 standard atmosphere (atm) or less is maintained in the sealed space.

Morphology 5: One or more embodiments of the present invention provide a heating cooker characterized in that an inner side wall portion of the inner container or an outer side wall portion of the outer container is provided with the working fluid A plurality of tubes used when injected into the sealed space and when the sealed space is made into a negative pressure or a vacuum.

Aspect 6: One or more embodiments of the present invention provide a heating cooker characterized in that a plurality of tubes are disposed at equal intervals in a circumferential direction of the heating cooker, and the tube is covered with the tube The tube cover.

Aspect 7: One or more embodiments of the present invention provide a heating cooker characterized in that an outer side of the inner container is bent between an inner bottom wall portion and an inner side wall portion of the inner container. The convex inner corner portion is set such that the radius of the inner corner portion gradually decreases as going from the inner bottom wall portion to the inner side wall portion.

Aspect 8: An embodiment of one or more aspects of the present invention provides a heating cooker characterized in that a surface constituting the sealed space of the inner container and a surface of the outer container constituting the sealed space are implemented Specular processing.

Effect of the invention

According to one or more embodiments of the present invention, the side wall of the inner side of the heating cooker can be efficiently heated.

The invention will be described in detail below with reference to the drawings.

(First embodiment)

Next, the inner pot 30 as the "heating cooker" of the first embodiment will be described with reference to Figs. 1 to 8 . The inner pot 30 constitutes a part of the rice cooker 10 as a pot for cooking rice. Therefore, in the following description, the structure of the rice cooker 10 will first be described. Next, the structure of the inner pot 30 will be described. Further, an arrow UP appropriately displayed in the drawing indicates the upper side of the rice cooker 10 and the inner pot 30. In the following description, when the vertical direction is described, the vertical direction of the rice cooker 10 and the inner pot 30 is shown unless otherwise specified.

(about rice cooker 10)

As shown in Fig. 5, the rice cooker 10 is an IH (induction heating) type rice cooker, and includes a rice cooker main body 12 and a lid portion 24.

<About rice cooker main body 12>

The rice cooker main body 12 has an inner pot accommodating portion 14 for accommodating the inner pot 30 to be described later. The inner pan accommodating portion 14 has a concave shape that is open to the upper side, and is formed in a substantially circular shape when viewed from the upper side. A heating portion 16 for heating the inner pot 30 is provided on the lower side of the inner pot accommodating portion 14. The heating unit 16 is composed of an induction coil, and the induction coil is wound in a substantially spiral shape on the lower side of the inner pot accommodating portion 14.

Further, a power supply unit 18 is provided on the lower side of the heating unit 16, and a high-frequency current is applied to the heating unit 16 (induction coil) via the power supply unit 18. As a result, a high-frequency current is applied to the heating unit 16 (induction coil), an eddy current is generated in the inner pot 30 to be described later, and the inner pot 30 starts to generate heat by the electric resistance in the inner pot 30. Further, a temperature sensor 20 is provided below the central portion of the inner pot accommodating portion 14. The temperature sensor 20 is configured as a sensor that measures the temperature of the bottom of the inner pot 30. Further, a control unit 22 to which the power supply unit 18 and the temperature sensor 20 are electrically connected is provided in an upper portion of the rice cooker main body 12. Further, the control unit 22 controls the power supply unit 18 based on the output signal from the temperature sensor 20.

<About the cover 24>

The lid portion 24 is rotatably coupled to the upper portion of the rice cooker main body 12 by the hinge mechanism 26, and covers the opening portion of the inner pot storage portion 14. In addition, the opening portion of the inner pot accommodating portion 14 is opened and closed by rotating the lid portion 24 from this state, and the inner pot 30, which will be described later, can be housed in the inner pot accommodating portion 14.

(About inner pot 30)

As shown in FIGS. 1 to 3, the inner pot 30 is formed in a substantially bottomed cylindrical shape that is open to the upper side, and has a double wall structure having a sealed space 36 therein. Specifically, the inner pot 30 is composed of an inner container 32 constituting an inner portion of the inner pot 30 and an outer container 34 constituting an outer portion of the inner pot 30. Further, a working fluid 40 is injected into the sealed space 36 of the inner pot 30. Further, the inner pot 30 includes a coupling pin 42 that connects the inner container 32 and the outer container 34 (in a broad sense, an element that is grasped as a "connection portion"), and a cover that covers the flange of the inner pot 30 formed in the opening portion. 50. Next, each structure of the inner pot 30 will be described.

<About the inner container 32>

The inner container 32 is made of a magnetic material (in the present embodiment, as an example, stainless steel), and is formed in a substantially bottomed cylindrical shape that is open to the upper side. Specifically, the inner container 32 is composed of an inner bottom wall portion 32A constituting a bottom portion of the inner container 32, a cylindrical inner side wall portion 32B constituting a side portion of the inner container 32, and an inner bottom wall portion 32A and an inner side wall portion 32B. The inner corner portion 32C is formed. The inner bottom wall portion 32A is formed in a substantially disk shape in which the upper and lower directions are in the thickness direction. Further, in the longitudinal section, the inner bottom wall portion 32A is gradually inclined downward from the central portion toward the radially outer side. In other words, the inner bottom wall portion 32A is formed by bending a portion in which the central portion of the inner bottom wall portion 32A is convex upward.

In the longitudinal section, the inner corner portion 32C is curved so as to be convex toward the outer side of the inner container 32 (toward the radially outer side and the lower side of the inner container 32) to have an approximately eleventh elliptical shape, and the inner bottom wall is smoothly formed. The outer peripheral end of the portion 32A is connected to the lower end of the inner side wall portion 32B. Specifically, in the longitudinal cross-sectional view, the radius R of the inner corner portion 32C is set to gradually decrease from the outer peripheral end portion of the inner bottom wall portion 32A toward the lower end portion of the inner side wall portion 32B. That is, the radius R1 of the radius R corresponding to the outer peripheral end portion of the inner bottom wall portion 32A is set to be larger than the radius R2 of the radius R corresponding to the lower end portion of the inner side wall portion 32B.

A first flange 32D that protrudes outward in the radial direction of the inner container 32 is formed in the opening of the inner side wall portion 32B, and the first flange 32D extends over the entire circumference of the inner side wall portion 32B. The first flange 32D is formed by hemming or the like, and is bent into a substantially U shape that is open to the radially inner side of the inner container 32. Specifically, the first flange 32D is formed by an upper flange portion 32D1 that is bent at an outer side in the radial direction of the inner container 32 at an opening end portion of the inner side wall portion 32B by substantially 90 degrees, and an upper flange portion 32D1. The front end portion is formed to the lower flange portion 32D2 which is folded back substantially 180 degrees toward the radially inner side of the inner container 32. Further, between the upper flange portion 32D1 and the lower flange portion 32D2, a second flange 34D of an outer container 34 to be described later is disposed, and the second flange 34D is joined to the first flange 32D.

In addition, a layer made of a heat-resistant fluororesin processed product or a Teflon (registered trademark) is formed on the inner peripheral surface of the inner container 32. On the other hand, the outer surface of the inner container 32 (specifically, the surface constituting the sealed space 36) is mirror-finished.

<About outer container 34>

Similarly to the inner container 32, the outer container 34 is made of a magnetic material (in this embodiment, stainless steel as an example), and is formed in a substantially bottomed cylindrical shape that is open to the upper side. Specifically, the outer container 34 is composed of an outer bottom wall portion 34A constituting the bottom portion of the outer container 34, a cylindrical outer side wall portion 34B constituting a side portion of the outer container 34, and an outer peripheral end portion and an outer side connecting the outer bottom wall portion 34A. The outer corner portion 34C of the lower end portion of the side wall portion 34B is configured. Further, in the present embodiment, the thicknesses of the inner container 32 and the outer container 34 are set to be the same, and the inner container 32 and the outer container 34 are all set to have a uniform (constant) thickness.

The outer side wall portion 34B is formed in a cylindrical shape having a larger diameter than the inner side wall portion 32B of the inner container 32, and is disposed coaxially with the inner container 32 on the outer side in the radial direction of the inner side wall portion 32B. In addition, the outer bottom wall portion 34A is formed in a circular flat plate shape in the upper and lower directions in the thickness direction, and is disposed on the lower side of the inner bottom wall portion 32A of the inner container 32. In other words, when the inner pan 30 is housed in the inner pan accommodating portion 14 of the rice cooker 10, the outer bottom wall portion 34A is in close contact with the bottom surface of the inner pan accommodating portion 14. Further, similarly to the inner bottom wall portion 32A of the inner container 32, the outer bottom wall portion 34A may be curved such that the central portion of the outer bottom wall portion 34A is convex upward.

Similarly to the inner corner portion 32C, the outer corner portion 34C is curved in a substantially eleventh elliptical shape so as to be convex toward the outer side (downward side and outward in the radial direction of the outer container 34) of the outer container 34 in the longitudinal cross-sectional view. The outer peripheral end portion of the outer bottom wall portion 34A and the lower end portion of the outer side wall portion 34B are smoothly connected. Specifically, in the longitudinal cross-sectional view, the radius of the inner corner portion 32C is set to gradually decrease from the outer peripheral end portion of the outer bottom wall portion 34A toward the lower end portion of the outer side wall portion 34B.

A second flange 34D that protrudes outward in the radial direction is formed at the opening end of the outer side wall portion 34B. The second flange 34D is bent outward in the radial direction of the outer container 34 by approximately 90 degrees at the opening end of the outer side wall portion 34B, and extends over the entire circumference of the outer side wall portion 34B in the circumferential direction. Further, the second flange 34D is disposed between the upper flange portion 32D1 and the lower flange portion 32D2 of the first flange 32D of the inner container 32, and is pressed by the first flange 32D to be joined to the both. That is, at the time of molding the first flange 32D, the first flange 32D is bent such that the upper flange portion 32D1 and the lower flange portion 32D2 of the first flange 32D press the second flange 34D up and down. forming. Thereby, the outer container 34 is assembled to the inner container 32, and a sealed space 36 having a substantially U-shape which is open upward in the longitudinal section is formed between the inner container 32 and the outer container 34. Further, the front end portion of the first flange 32D is joined to the second flange 34D by arc welding or the like. Further, in addition to the joining of the front end portion of the first flange 32D and the second flange 34D, the overlapping portions of the first flange 32D and the second flange 34D that overlap in the vertical direction may be spot-welded and seamless. Welding, laser welding, etc., and joining the two together. Thereby, it becomes a structure which ensures the airtightness of the sealing space 36. Further, the inner surface of the outer container 34 (the surface constituting the sealed space 36) is mirror-finished.

Here, the sealed space 36 will be described.

As described above, the sealed space 36 is formed in a substantially U-shape that is hollow when viewed in a longitudinal section. In the present embodiment, the bottom portion 36A of the sealed space 36 is a region (space) lower than the inner side surface of the inner bottom wall portion 32A of the inner container 32 (see FIGS. 1 and 3). The position indicated by the double-dot chain line L1 is located on the lower side of the area). Therefore, in the present embodiment, the inner side surface of the outer container 34 constituting the bottom portion 36A of the sealed space 36 is the bottom surface 36B of the sealed space 36, and the bottom surface 36B is defined by the inner side surface and the outer side angle of the outer bottom wall portion 34A of the outer container 34. A part of the inner side surface of the portion 34C is configured.

Further, as will be described later, the working fluid 40 is stored on the bottom surface 36B, and when a high-frequency current is applied to the heating portion 16 (induction coil), the outer bottom wall portion 34A of the magnetic body starts to generate heat, and the working fluid 40 is heated.

In the sealed space 36, the height H of the bottom portion 36A of the sealed space 36 (the upper and lower dimensions between the inner bottom wall portion 32A and the outer bottom wall portion 34A, see FIG. 3) is set as the side portion 36C of the sealed space 36. The width dimension W (the radial dimension of the inner pot 30 between the inner side wall portion 32B and the outer side wall portion 34B, see FIG. 3) is equal to or greater than 2 mm. In the present embodiment, the height dimension H of the bottom portion 36A is set to 4 mm, and the width dimension W of the side portion 36C is set to 2 mm. Moreover, when considering the enlargement of the inner pot 30 and the practical level of the inner pot 30 as a pot, it is preferable to set the height dimension H of the bottom part 36A to 10 mm or less. Further, since the inner bottom wall portion 32A is curved so as to be convex toward the upper side as described above, the height dimension H changes in the radial direction of the inner pot 30. Therefore, in the present embodiment, the height dimension H is the minimum value of the vertical dimension between the inner bottom wall portion 32A and the outer bottom wall portion 34A. In addition, in the drawings, the width of the side portion 36C of the sealed space 36 is exaggerated for convenience.

In the description of returning to the outer container 34, a circular through hole 34E is formed at an upper portion of the outer side wall portion 34B of the outer container 34 and at a position below the second flange 34D. In the outer side wall portion 34B of the outer container 34 and at a position corresponding to the through hole 34E, a tube 38 for evacuating the working fluid 40 and the sealed space 36 into the sealed space 36 to be described later is provided. The tube 38 and the through hole 34E are disposed coaxially, and the base end portion of the tube 38 is joined to the outer side wall portion 34B by arc welding or the like. Thereby, the inside of the sealed space 36 communicates with the outside of the inner pot 30 by the tube 38 which protrudes outward in the radial direction of the inner pot 30 from the outer side wall part 34B.

Further, in the present embodiment, the working fluid 40 is injected from the tube 38 into the sealed space 36. In addition, after the working fluid 40 is injected into the sealed space 36, a vacuum pump (not shown) is attached to the tube 38, and the air in the sealed space 36 is discharged by the vacuum pump, and the inside of the sealed space 36 is maintained at a negative temperature of less than 0.1 atm. The pressure (more preferably a negative pressure of 0.01 atm or less) or a vacuum setting. Further, the tube for injecting the working fluid 40 and the tube for vacuum evacuation are not required to be common, and may be separately provided.

A caulking portion 38A is formed at the front end portion of the tube 38, and the front end portion of the tube 38 is sealed by the caulking portion 38A. Specifically, while the air in the sealed space 36 is discharged by the vacuum pump, the front end portion of the tube 38 is swaged, and the portion after the swaging process is cut, whereby the caulking portion 38A is molded. Further, the caulking portion 38A is flattened up and down, and is formed in a substantially plate shape in which the upper and lower directions are in the thickness direction. Further, the front end portion of the caulking portion 38A is sealed by arc welding or the like. Thereby, the airtightness of the sealed space 36 is ensured.

<About working fluid 40>

In the present embodiment, water is used as the working fluid 40. Further, the working fluid 40 is injected into the sealed space 36 from the above-described tube 38, and stored in the bottom portion 36A of the sealed space 36. Further, the volume ratio of the working fluid 40 to the bottom portion 36A in the sealed space 36 is set to 4 vol% to 80 vol%. That is, in the storage state of the working fluid 40, the entire bottom portion 36A of the sealed space 36 is not immersed in water by the working fluid 40, but is in the upper portion of the bottom portion 36A of the sealed space 36 and in the working fluid 40 and the inner bottom wall portion 32A. There is a gap formed between them. More specifically, in the present embodiment, the amount of the working fluid 40 in the sealed space 36 is set such that the working fluid 40 does not cover the entire bottom surface 36B of the bottom portion 36A of the sealed space 36. Thereby, in a state in which the working fluid 40 is disposed on the bottom surface 36B of the sealed space 36, a plurality of water-like working fluids 40 are dispersedly disposed on the bottom surface 36B. Further, in the present embodiment, as described above, the volume ratio of the working fluid 40 in the sealed space 36 to the bottom portion 36A is set to 4 vol% to 80 vol%, but it is preferable to set the volume ratio to 5 vol% to 20 vol%. It is preferably set to 7 vol% to 15 vol%, and particularly preferably set to 8 vol% to 12 vol%.

<About the joint pin 42>

The connecting pin 42 is composed of a magnetic body (in the present embodiment, stainless steel as an example). The connecting pin 42 is formed in a substantially columnar shape in which the upper and lower directions are axial, and the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pot 30 are coupled together. Specifically, the coupling pin 42 includes a center pin 44 that connects the center portion of the inner bottom wall portion 32A and the center portion of the outer bottom wall portion 34A, and an outer peripheral portion that connects the inner bottom wall portion 32A and the outer peripheral portion of the outer bottom wall portion 34A. A plurality of (four in the present embodiment) outer peripheral pins 46 are formed. Further, the outer peripheral pins 46 are disposed at equal intervals (every 90 degrees) in the circumferential direction of the inner pot 30.

Further, in the present embodiment, the upper end portion of the coupling pin 42 is joined to the inner bottom wall portion 32A of the inner container 32 by arc welding or the like. On the other hand, after the inner container 32 and the outer container 34 are assembled, the lower end portion of the coupling pin 42 is joined to the outer bottom wall portion 34A of the outer container 34 by laser welding or the like from the outside of the outer container 34. Further, in the present embodiment, the coupling pin 42 is composed of the center pin 44 and the outer circumferential pin 46. However, in the coupling pin 42, the outer circumferential pin 46 may be omitted, and only the coupling pin 42 may be the center pin 44.

<About cover 50>

As shown in FIG. 1, FIG. 3, and FIG. 4, the cover 50 is formed in a circular ring shape, and covers the first flange 32D of the inner container 32 and the tube 38 from the radially outer side of the inner pot 30. The cover 50 is composed of a heat-resistant resin (in the present embodiment, as an example, a heat-resistant ABS). Further, the cover 50 is divided into two in a plan view and is constituted by a pair of cover members 52. The pair of cover members 52 have a semicircular shape (a substantially C-shape) that is open to the center side of the inner pot 30 in plan view, and is formed to the inner pot 30 when viewed from the circumferential direction (longitudinal direction). A concave shape that is open on the radially inner side. Specifically, the cover member 52 is formed by the outer peripheral wall 52A constituting the outer peripheral portion of the cover member 52, and the upper wall 52B projecting from the upper end portion of the outer peripheral wall 52A toward the radially inner side of the cover member 52, from the lower end portion of the outer peripheral wall 52A. The lower wall 52C of the cover member 52 projecting radially inward is formed. Further, between the upper wall 52B and the lower wall 52C, a pair of upper and lower intermediate walls 52D projecting radially inward from the intermediate portion in the vertical direction of the outer peripheral wall 52A are formed, and the intermediate wall 52D is disposed to be opposed to the upper wall 52B and the lower wall 52C. Parallel, extending in the circumferential direction of the cover member 52.

The upper side portion of the inside of the cover member 52 (the space between the upper intermediate wall 52D and the upper wall 52B) is referred to as a first housing portion 52E. Further, the first flange 32D of the inner pot 30 is fitted into the first housing portion 52E, and the cover member 52 is fixed to the inner pot 30. In other words, the first flange 32D (including the second flange 34D) of the inner pot 30 is covered from the radially outer side by the cover member 52. Further, the lower portion of the inside of the cover member 52 (the space between the lower intermediate wall 52D and the lower wall 52C) is referred to as a second housing portion 52F. Further, the tube 38 of the inner pot 30 is housed in the second housing portion 52F. Thereby, the tube 38 is covered from the radially outer side of the inner pot 30 by the cover member 52.

In addition, a buckle 52G that protrudes outward in the radial direction is formed on the outer peripheral wall 52A of one cover member 52 and at both end portions in the longitudinal direction (see FIG. 4). Further, in the outer peripheral wall 52A of the other cover member 52, the engaging pieces 52H projecting toward the one cover member 52 side are formed at both end portions in the longitudinal direction (see FIG. 4), and the distal end side of the engaging piece 52H is formed. In part, an engaging hole 52J that engages with the buckle 52G is formed (see FIG. 4). Thereby, the cover 50 covers the first flange 32D and the tube 38 from the radially outer side of the inner pot 30 in a state in which the pair of cover members 52 are engaged.

Further, as the cover member 52 is fixed to the inner pot 30, the above-described buckle 52G and the engagement piece 52H may be omitted, and only the first flange 32D may be fitted into the first housing portion 52E. Further, the cover member 52 may be coupled to the first flange 32D by screws, rivets or the like to fix the cover member 52 to the inner pot 30. Further, the cover 50 is not limited to being divided into two, and a configuration in which the cover 50 is divided into three or more pieces may be employed.

(action and effect)

Next, the action and effect of the present embodiment will be described.

When the inner pot 30 and the rice cooker 10 configured as described above are used for cooking, the inner pot 30 is housed in the inner pot accommodating portion 14 of the rice cooker 10, and the bottom portion of the inner pot 30 is heated by the heating portion 16 of the rice cooker 10. Specifically, an eddy current is generated in the inner pot 30 by applying a high-frequency current to the heating unit 16 (induction coil). Thereby, the bottom of the inner pot 30 starts to generate heat, and the working fluid 40 in the sealed space 36 is heated.

When the temperature of the heated working fluid 40 reaches the boiling point, the working fluid 40 boils and a part of the working fluid 40 is vaporized. The vaporized vapor is instantaneously diffused into the sealed space 36, and the inner side wall portion 32B of the inner pot 30 is heated. Then, the vapor after the inner side wall portion 32B of the inner pot 30 is heated starts to condense, and the liquid is changed from the gas to the liquid as the working liquid 40. The working fluid 40 that has become a liquid returns to the bottom portion 36A of the sealed space 36 by its own weight. Further, in the working fluid 40, the inner side wall portion 32B of the inner pot 30 is heated by repeating the cycle of the above-described phase change, and the cooking material (rice) in the inner pot 30 is heated. Since the vapor of the working fluid 40 brings the entire wall surfaces of the inner container 32 and the outer container 34 surrounding the sealed space 36 to the same temperature, the inner bottom wall portion 32A, the inner side wall portion 32B, and the inner corner portion 32C of the inner container 32 are time-outless. The heat is stagnation and is substantially uniformly heated while the temperature of the inner container 32 rises.

Fig. 6 is a view showing an example of temperature data of the inner pot 30 and the rice when the inner pot 30 of the present embodiment is used for cooking. In the graph, the horizontal axis represents the time (minutes) from the start of cooking, and the vertical axis represents temperature (°C). In addition, the solid line shown in FIG. 6 is measurement data of the upper portion of the inner side wall portion 32B of the inner pot 30, and the broken line is measurement data of the central portion of the inner bottom wall portion 32A of the inner pot 30, and the dotted line is the inner pot 30. The measurement data of the upper portion of the rice inside, and the two-dot chain line are measurement data of the lower portion of the rice in the inner pot 30.

Further, as shown in the figure, it is understood that the temperature of the inner side wall portion 32B of the inner pot 30 and the inner bottom portion of the inner pot 30 at the start of the "cooking section" starting from the start of cooking to approximately 20 minutes later. The temperature of the wall portion 32A was equally raised to 100 °C. In the "cooking section" and the "steamed rice section" after the temperature of the inner pot 30 has reached 100 ° C, the temperature difference between the inner side wall portion 32B and the inner bottom wall portion 32A is negligible. The inner pot 30 is also heated.

Further, it is understood that the temperature of the upper portion and the lower portion of the rice rises as the temperature of the inner side wall portion 32B and the inner bottom wall portion 32A of the inner pot 30 rises at the beginning of the "cooking section". In other words, it can be seen that the temperature difference between the inner side wall portion 32B and the inner bottom wall portion 32A of the inner pot 30 and the upper and lower portions of the rice can be reduced, and rice can be cooked.

In addition, in the present embodiment, it has been found that even in the so-called quick cooking in which the "soaking section" in the cooking rice is omitted and the rice cooking section is used as the "cooking section", the cooking can be performed in a short time. Cook rice. That is, in the case where the quick cooking is usually performed, in order to prevent excessive evaporation of water (hereinafter referred to as "soaking water") of the rice soaked in the fast cooking, heating of the rice cooker 10 is performed during the rice cooking process. The output of the portion 16 (inductive coil) is controlled relative to the output of the rice cooking start. Therefore, during the cooking process, the above output is temporarily lowered, so that the time until the end of the cooking is rapidly extended.

On the other hand, in the case of the rapid cooking using the inner pot 30 of the present embodiment, it has been found that excessive evaporation of the soaking water during rapid cooking can be suppressed. Therefore, it has been confirmed that even if the output of the heating unit 16 (induction coil) of the rice cooker 10 is set to a constant output from the start to the end of cooking, and the inner pot 30 is heated, it is cooked no more than usual cooking. The rice that was cooked was inferior to the rice. Thus, by setting the output of the heating unit 16 (induction coil) of the rice cooker 10 to a constant output from the start to the end of cooking, the time for rapid cooking can be further shortened.

Here, in the inner pot 30 of the present embodiment, the volume ratio of the working fluid 40 in the sealed space 36 to the bottom portion 36A is set to 4 vol% to 80 vol%. Specifically, the plurality of working fluids 40 are injected into the bottom surface 36B of the sealed space 36 in a drop shape so as not to cover the entire bottom surface 36B of the sealed space 36. Thereby, the inner side wall portion 32B of the inner container 32 can be efficiently heated.

Hereinafter, this point will be described using the graph shown in Fig. 7. The graph shown in Fig. 7 shows an example of data obtained by measuring the temperature of the inner pot 30 when the volume ratio of the working fluid 40 to the bottom portion 36A is changed during cooking of the inner pot 30. Further, in each graph of Fig. 7, the horizontal axis represents the time (minutes) from the start of rice cooking, and the vertical axis represents the temperature (°C). Further, the solid line of each graph is the measurement data of the upper portion of the inner side wall portion 32B of the inner pot 30, the broken line is the measurement data of the lower portion of the inner side wall portion 32B, and the dashed line is the center of the inner bottom wall portion 32A of the inner pot 30. The measurement data of the portion, the two-dot chain line, is measurement data of the outer peripheral portion of the inner bottom wall portion 32A. Further, in Fig. 7(A), the volume ratio is set to 3 vol%, and in Fig. 7(B), the volume ratio is set to 10 vol%, and in Fig. 7(C), the volume is set. The ratio was set to a value greater than 80 vol% (approximately 85 vol%).

As shown in Fig. 7(A), it has been found that when the volume ratio is set to 3 vol% or less, the phase change cycle of the working fluid 40 occurs (the vaporization starts from the liquid and becomes vapor, and the vapor starts to condense. The circulation period of the liquid is restored, but the behavior of the temperature rise of the entire inner pot 30 is unstable.

Further, as shown in Fig. 7(C), it has been found that when the volume ratio exceeds 80 vol%, the phase change cycle efficiency of the vapor is lowered, and between the inner bottom wall portion 32A and the inner side wall portion 32B of the inner pot 30. The temperature difference is increased, and the temperature uniformity of the entire inner pot 30 is not obtained.

On the other hand, as shown in Fig. 7(B), it has been found that when the volume ratio is set to 10 vol%, the entire inner pot 30 is well subjected to the vapor phase change cycle, and the inner pot 30 is suppressed. The temperature rises in a state where the temperature difference between the inner bottom wall portion 32A and the inner side wall portion 32B is increased, and the entire inner pot 30 is heated substantially uniformly.

As described above, by setting the volume ratio of the working fluid 40 in the sealed space 36 to the bottom portion 36A to 4 vol% to 80 vol%, the inner side wall portion 32B of the inner container 32 can be efficiently heated, and the inner pot can be substantially uniformly 30 overall heating.

In the inner pot 30, the height H of the bottom portion 36A of the sealed space 36 is set to be equal to or larger than the width dimension W of the side portion 36C, and is set to 2 mm or more. Therefore, the inner side wall portion 32B of the inner container 32 can be heated more efficiently.

In other words, it has been found that when the height dimension H is set to be smaller than the width dimension W and smaller than 2 mm, the working fluid 40 which is condensed and returned to the liquid during the phase change cycle of the working fluid 40 is directed from the side portion 36C of the sealed space 36. The return efficiency of the bottom 36A return is lowered, and the effect of uniformly heating the inner pot 30 is lowered. Therefore, as described above, by setting the height dimension H to the width dimension W or more and setting it to 2 mm or more, it is possible to suppress the return of the working fluid 40 which has been condensed and returned to the liquid, from the side portion 36C of the sealed space 36 to the bottom portion 36A. The efficiency is lowered and the effect of uniform heating of the inner pot 30 can be improved. As described above, the inner side wall portion 32B of the inner container 32 can be heated more efficiently.

Further, the inside of the sealed space 36 is set to maintain a negative pressure (less preferably a negative pressure of 0.01 atm or less) or a vacuum of less than 0.1 atm. Therefore, the inner side wall portion 32B of the inner container 32 can be heated more efficiently.

That is, as shown in Fig. 8, the vapor generated in the sealed space 36 rises along the inner side wall portion 32B of the inner pot 30 (refer to the arrow in Fig. 8). At this time, when a negative pressure of more than 0.1 atm is formed in the sealed space 36, the residual air A (refer to a portion indicated by a chain double-dashed line) in the sealed space 36 rises along the inner side wall portion 32B. The vapor is pushed to the upper end side of the sealed space 36. In other words, in this case, the residual air A in the sealed space 36 serves as a resistance layer against the vapor when the vapor rises, and tends to prevent the vapor from rising. In addition, by making the inside of the sealed space 36 into a negative pressure state of less than 0.1 atm, the resistance of the residual air A to the vapor to be raised can be reduced, and the vapor can be raised to the upper end side of the sealed space 36, so that the vapor can be favorably passed. The inner side wall portion 32B is heated. In addition, by maintaining the inside of the sealed space 36 at a negative pressure or a vacuum of 0.01 atm or less, the inner side wall portion 32B can be more preferably heated by steam. Therefore, by setting the inside of the sealed space 36 to a negative pressure (less preferably a negative pressure of 0.01 atm or less) or a vacuum of less than 0.1 atm, the inner side wall portion 32B of the inner container 32 can be heated more satisfactorily.

Moreover, the radius R of the inner corner portion 32C of the inner pot 30 is set to gradually decrease from the outer peripheral end portion of the inner bottom wall portion 32A toward the lower end portion of the inner side wall portion 32B. That is, the radius R1 of the radius R corresponding to the outer peripheral end portion of the inner bottom wall portion 32A is set to be larger than the radius R2 of the radius R corresponding to the lower end portion of the inner side wall portion 32B. Thereby, it is possible to reduce the capacity of the inner pot 30 (the amount of rice that can be cooked), and to efficiently cause the vapor generated in the sealed space 36 to move along the inner corner portion 32C of the inner pot 30 toward the inner side wall portion 32B side. rise. This point will be described below.

In other words, in the case where the radial direction of the inner pot 30 is not changed, and the radius R of the inner corner portion 32C is set to be constant and the radius R1 corresponding to the outer peripheral end portion of the inner bottom wall portion 32A is set to be constant, (Hereinafter, this case is referred to as a comparative example), and the lower portion of the inner corner portion 32C enters the radially inner side of the present embodiment. That is, the diameter of the inner bottom wall portion 32A is reduced. Thus, in the comparative example, the capacity of the inner pot 30 tends to decrease.

Further, in the comparative example, the inclination angle of the tangent line tangential to the inner corner portion 32C with respect to the horizontal direction gradually increases toward the radially outer side of the inner container 32 in the longitudinal section.

On the other hand, in the present embodiment, the radius R of the inner corner portion 32C of the inner container 32 is set to gradually decrease from the outer peripheral portion of the inner bottom wall portion 32A toward the lower end portion of the inner side wall portion 32B. Therefore, in the longitudinal cross-sectional view, the inclination angle of the tangent line tangential to the inner corner portion 32C with respect to the horizontal direction increases more sharply than the comparative example in the radial outer side of the inner container 32. In other words, the inner corner portion 32C is formed to rise more sharply than the comparative example. Thus, the resistance to the vapor rising along the inner corner portion 32C of the inner pot 30 can be reduced as compared with the comparative example, and the vapor can be efficiently raised toward the inner side wall portion 32B side.

Further, in the present embodiment, the lower end portion of the inner corner portion 32C can be disposed radially outward of the comparative example. That is, the diameter of the inner bottom wall portion 32A can be made larger than that of the comparative example. Thereby, the capacity of the inner pot 30 can be made larger than the comparative example.

As described above, according to the inner pot 30 of the present embodiment, it is possible to efficiently reduce the vapor in the sealed space 36 to the inner side wall portion along the inner corner portion 32C of the inner container 32 while reducing the capacity of the inner pot 30. The 32B side rises.

Further, the surface of the inner pot 30 constituting the sealed space 36 is mirror-finished. Therefore, in the sealed space 36, the resistance against the vapor when the vapor rises along the inner corner portion 32C and the inner side wall portion 32B of the inner pot 30 can be reduced. Thereby, the vapor of the sealed space 36 can be favorably raised to the upper end side of the sealed space 36. As a result, the entire inner container 32 can be efficiently heated.

In addition, it is possible to reduce the resistance of the walls to the working fluid 40 when the working fluid 40 that has become condensed and becomes liquid is lowered. Thereby, the working fluid 40 can be satisfactorily returned to the bottom portion 36A of the sealed space 36.

Further, a coupling pin 42 is provided in the sealed space 36 of the inner pot 30, and the coupling pin 42 connects the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pan 30 together. Further, during the heating of the inner pot 30, the air pressure in the sealed space 36 rises, and the inner bottom wall portion 32A and the outer bottom wall portion 34A are vertically expanded. At this time, since the inner bottom wall portion 32A and the outer bottom wall portion 34A are coupled by the joint pin 42, the inner bottom wall portion 32A and the outer bottom wall portion 34A function to be mutually stretched by the joint pin 42. With this, the expansion of the inner bottom wall portion 32A and the expansion of the outer bottom wall portion 34A to the lower side when the inner pan 30 is heated can be suppressed, and the deformation of the bottom portion of the inner pan 30 can be suppressed. .

Further, the coupling pin 42 is constituted by a pin whose upper and lower directions are the axial direction. Therefore, in the bottom portion 36A of the sealed space 36, the flow of the working fluid 40 and the vapor which is a gas is not inhibited, and the inner bottom wall portion 32A and the outer bottom wall portion 34A can be coupled by the joint pin 42.

Further, the coupling pin 42 has a center pin 44 that connects the central portion of the inner bottom wall portion 32A of the inner pot 30 and the central portion of the outer bottom wall portion 34A. Therefore, the vertical displacement of the central portion of each of the inner bottom wall portion 32A and the outer bottom wall portion 34A can be suppressed by the joint pin 42. Thereby, at the time of expansion, the displacement of the portion where the displacement amount is the largest can be suppressed to the inner bottom wall portion 32A and the outer bottom wall portion 34A. Therefore, the expansion of the inner bottom wall portion 32A and the outer bottom wall portion 34A can be effectively suppressed.

Further, a tube 38 that protrudes outward in the radial direction of the inner pot 30 is provided on the outer side wall portion 34B of the inner pot 30. Further, before the caulking portion 38A of the tube 38 is formed, the inside of the sealed space 36 of the inner pot 30 and the outside of the inner pot 30 communicate with each other through the tube 38. Thereby, the working fluid 40 can be easily injected into the sealed space 36 by the tube 38. Further, by installing a vacuum pump in the tube 38, the air in the sealed space 36 can be discharged from the tube 38, and the inside of the sealed space 36 can be made into a negative pressure or a vacuum state. Therefore, workability at the time of production of the inner pot 30 can be improved.

Further, in the inner pot 30, the first flange 32D (second flange 34D) of the inner pot 30 and the tube 38 are covered from the radially outer side of the inner pot 30 by the cover 50. Therefore, even if the tube 38 which improves the workability at the time of manufacture of the inner pot 30 is provided in the outer side wall part 34B, the tube 38 cannot be recognized by the cover 50. In addition, the cover 50 can be flexibly used as the handle of the inner pot 30. As described above, it is possible to improve the design of the inner pan 30 and improve the convenience of the user.

Further, in the inner pot 30, the first flange 32D of the inner container 32 is crimped to the second flange 34D so as to be wound around the upper and lower sides of the second flange 34D of the outer container 34 by hemming or the like. That is, the overlapping portion of the inner container 32 and the outer container 34 is closed by a so-called labyrinth structure (maze structure). Thereby, the airtightness in the sealed space 36 formed by the inner container 32 and the outer container 34 can be ensured.

Further, in the present embodiment, as described above, the inner pot 30 has a double wall structure having a sealed space 36 therein, and the inside of the sealed space 36 is in a negative pressure or a vacuum state. Therefore, the heat retention of the inner pot 30 after cooking can be improved.

(Modification of inner pot 30)

Next, the inner pot 60 of the modification will be described with reference to Fig. 9.

The inner pot 60 of the modification is the same as the inner pot 30 of the first embodiment except for the following points. In the ninth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals.

That is, in the inner pot 60 of the modification, a part of the bottom of the inner pot 60 is formed in a solid shape. Specifically, in the inner container 32, the inner bottom wall portion 32A is omitted, and the inner container 32 is formed in a substantially cylindrical shape. Further, in the outer container 34, the outer bottom wall portion 34A is omitted, and the outer container 34 is formed in a substantially cylindrical shape. Further, a bottom plate 62 having a substantially solid disk shape is provided on the inner side in the radial direction of the inner pot 60 with respect to the inner corner portion 32C of the inner container 32 and the outer corner portion 34C of the outer container 34. Similarly to the inner container 32 and the outer container 34, the bottom plate 62 is made of a magnetic material (in this case, stainless steel as an example). Further, the outer peripheral portion of the bottom plate 62 is joined to the inner corner portion 32C and the outer corner portion 34C by arc welding or the like.

Thereby, in the inner pot 60, the sealed space 36 becomes a space between the inner corner portion 32C and the inner side wall portion 32B, and the outer corner portion 34C and the outer side wall portion 34B. Further, a part of the inside of the corner portion of the inner pot 60 (portion between the inner corner portion 32C and the outer corner portion 34C) constitutes the bottom portion 36A of the sealed space 36. Further, in the inner pot 60, since the bottom of the inner pot 60 is constituted by the bottom plate 62, the joint pin 42 of the inner pot 30 of the present embodiment is omitted.

Further, in the inner pot 60 of the modification, when the bottom portion (the bottom plate 62) of the inner pot 60 is heated, the working liquid 40 injected into the sealed space 36 is also heated. When the temperature of the heated working fluid 40 reaches the boiling point, the working fluid 40 boils and a portion of the working fluid 40 begins to vaporize. Then, the vaporized vapor rises along the inner corner portion 32C and the inner side wall portion 32B in the sealed space 36 toward the side portion 36C side in the sealed space 36. Thereby, the inner side wall portion 32B of the inner pot 60 is heated by the steam. Further, the vapor of the inner side wall portion 32B is heated and condensed, and the liquid is changed from the gas to the liquid as the working fluid 40. Further, the working fluid 40 that has become a liquid is lowered by its own weight, and returns to the bottom portion 36A of the sealed space 36. Further, in the working fluid 40, the inner side wall portion 32B of the inner pot 30 is heated by repeating the cycle of the above phase change. As described above, even in the inner pot 60 of the modified example, the inner side wall portion 32B of the inner pot 60 can be efficiently heated as in the first embodiment.

Further, in the inner pot 60 of the modified example, the bottom portion 36A of the sealed space 36 is set in the corner portion of the inner pot 60. Therefore, when the working fluid 40 is vaporized into steam, the vapor can be immediately moved (raised) toward the side portion 36C side of the sealed space 36 along the inner corner portion 32C. Therefore, the vaporized vapor can be efficiently moved (raised) to the side portion 36C of the sealed space 36, and the inner side wall portion 32B of the inner pot 60 can be heated.

Further, in the inner pot 60 of the modified example, the sealed space 36 of the inner pot 60 becomes a space between the inner corner portion 32C and the inner side wall portion 32B and the outer corner portion 34C and the outer side wall portion 34B, but the closed space 36 may be used. The space between the outer corner portion 34C and the outer side wall portion 34B is set. In other words, the sealed space 36 only needs to include at least a space between the outer corner portion 34C and the outer side wall portion 34B. In this case, the lower portion of the inner pot 60 is formed in a solid shape than the lower two-dot chain line L2 of FIG.

(Modification of the method of connecting the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pot 30)

Next, two modifications of the method of connecting the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pot 30 will be described.

(Modification 1 of the connection method)

Next, a modification 1 of the connection method will be described using FIG. 10(A). In the first modification, the rest of the configuration is the same as that of the first embodiment except for the aspects shown below. In addition, in FIG. 10(A), the same components as those of the first embodiment are denoted by the same reference numerals.

In other words, in the first modification, the connecting pin 42 is omitted, and the connecting plate 70 is provided between the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pot 30 (in a broad sense, it is a "connecting portion". Element). The connecting plate 70 is formed in a substantially cross shape in plan view. Specifically, the connecting plate 70 is composed of a first connecting plate 72 and a pair of second connecting plates 74. The first connecting plate 72 and the second connecting plate 74 are formed in a substantially elongated plate shape, and the length of the first connecting plate 72 in the longitudinal direction is set to be substantially twice the length of the second connecting plate 74 in the longitudinal direction. Further, one end portion of the second connecting plate 74 in the longitudinal direction is joined to the central portion in the longitudinal direction of the first connecting plate 72, and the second connecting plate 74 is formed in the thickness direction of the first connecting plate 72 from the central portion in the longitudinal direction. Side extension. Thereby, four connection pieces 70A are formed in the connection plate 70, and the connection piece 70A radially protrudes from the center part of the connection plate 70.

In the plan view, the connecting plate 70 is disposed on the inner bottom wall portion 32A and the outer bottom wall portion such that the central portion of the connecting plate 70 overlaps the central portion of the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pot 30. Between 34A. Further, the upper end portion of the coupling plate 70 is joined to the inner bottom wall portion 32A, and the lower end portion of the coupling plate 70 is joined to the outer bottom wall portion 34A. Thereby, the inner bottom wall portion 32A and the outer bottom wall portion 34A are coupled by the connecting plate 70. Further, in this state, the bottom portion 36A of the sealed space 36 is in a state of being separated by the connecting plate 70.

Further, a plurality of communication holes 70B are formed in the lower end portion of each of the coupling pieces 70A of the coupling plate 70. Thereby, the bottom portion 36A of the sealed space 36 partitioned by the coupling plate 70 is configured to communicate through the communication hole 70B, and the working fluid 40 in the bottom portion 36A can flow in the bottom portion 36A of the partitioned space 36.

Further, in the first modification, as described above, the inner bottom wall portion 32A and the outer bottom wall portion 34A are coupled by the connecting plate 70. Therefore, similarly to the present embodiment, it is possible to suppress the expansion of the inner bottom wall portion 32A and the outer bottom wall portion 34A when the inner pot 30 is heated.

In the first modification, the connecting piece 70A of the connecting plate 70 radially protrudes from the central portion of the inner bottom wall portion 32A and the outer bottom wall portion 34A, and connects the inner bottom wall portion 32A and the outer bottom wall portion 34A. Together. Therefore, at the time of heating of the inner pot 30, the heat transmitted to the connecting plate 70 can be transmitted in the radial direction across the inner bottom wall portion 32A by the connecting piece 70A. Thereby, the inner bottom wall portion 32A can be heated substantially uniformly by the connecting piece 70A in the radial direction of the inner bottom wall portion 32A.

Further, a plurality of communication holes 70B are formed in the lower end portion of each of the coupling pieces 70A of the coupling plate 70. Therefore, even if the connecting plate 70 is disposed to partition the bottom portion 36A of the sealed space 36, the working fluid 40 in the bottom portion 36A can flow in the bottom portion 36A of the sealed space 36 partitioned by the connecting plate 70.

Further, in the first modification, four connection pieces 70A are formed on the coupling plate 70, but the number of the connection pieces 70A can be arbitrarily set.

(Deformation 2 of the connection method)

Next, a modification 2 of the connection method will be described using FIG. 10(B). In the modification 2, the rest of the configuration is the same as that of the first embodiment except for the aspects shown below. In addition, in FIG. 10(B), the same components as those of the first embodiment are denoted by the same reference numerals.

In other words, in the deformation 2, a substantially disk-shaped intermediate plate 80 is provided between the coupling pin 42 and the inner bottom wall portion 32A of the inner pan 30, and the intermediate plate 80 is made of a magnetic body similarly to the coupling pin 42. In the example, it is a stainless steel) as an example. That is, in the deformation 2, the intermediate plate 80 is interposed between the coupling pin 42 and the inner bottom wall portion 32A of the inner pot 30, and the intermediate plate 80 is joined to the coupling pin 42 and the inner bottom wall portion 32A. Therefore, at the time of heating of the inner pot 30, the heat transferred by the joint pin 42 is dispersed by the intermediate plate 80, and is transmitted to the entire inner bottom wall portion 32A of the inner pot 30. Thus, in the deformation 2, the inner bottom wall portion 32A of the inner pot 30 can be uniformly heated in the radial direction, and the expansion of the inner bottom wall portion 32A and the outer bottom wall portion 34A during heating can be suppressed.

(Second embodiment)

Next, the inner pot 90 as the "heating cooker" of the second embodiment will be described with reference to Figs. 11 and 12 .

The inner pot 90 of the second embodiment is the same as the inner pot 30 of the first embodiment except for the aspects described below. In the eleventh embodiment, the same components as those in the first embodiment are denoted by the same reference numerals. Further, in Fig. 11, in the inner pot 90, the cover 50 is omitted.

As shown in FIGS. 11(A) and (B), in the inner pot 90, the inner bottom wall portion 32A of the inner container 32 is disposed substantially horizontally along the surface orthogonal to the vertical direction (with the outer container 34). The outer bottom wall portions 34A are substantially parallel). In the inner pot 90, the joint pin 42 of the first embodiment is omitted, and a plurality of (in the present embodiment, three places) connection recesses 34F are formed in the outer bottom wall portion 34A of the outer container 34 (broadly speaking It is an element that is grasped as a "connection". The connecting recessed portion 34F is formed in a substantially inverted U-shaped concave shape that is open to the lower side in the longitudinal cross-sectional view, and protrudes upward from the outer bottom wall portion 34A. In addition, the three connection recessed portions 34F are disposed on the outer side in the radial direction of the inner pot 90 with respect to the central portion of the outer bottom wall portion 34A, and are disposed at equal intervals (every 120 degrees) in the circumferential direction of the inner pot 90. Further, the top of the coupling recess 34F is disposed adjacent to the lower surface of the inner bottom wall portion 32A of the inner container 32, and is joined to the inner bottom wall portion 32A by spot welding. Thereby, the inner bottom wall portion 32A and the outer bottom wall portion 34A are coupled together by the connection concave portion 34F. Further, as described above, in the second embodiment, the inner bottom wall portion 32A of the inner container 32 is disposed substantially horizontally along the surface orthogonal to the vertical direction, but the inner side may be the same as in the first embodiment. The bottom wall portion 32A is curved a certain amount in a convex manner toward the upper side.

Further, in the first flange 32D of the inner container 32, the lower flange portion 32D2 of the first embodiment is omitted. Further, the first flange 32D (upper flange portion 32D1) of the inner container 32 and the second flange 34D of the outer container 34 are disposed to overlap each other, and the front end portion of the first flange 32D and the second outer container 34 are disposed. The front end portions of the flanges 34D are joined together by laser welding or the like. Further, in addition to the joining of the front end portion of the first flange 32D and the front end portion of the second flange 34D, the overlapping portions of the first flange 32D and the second flange 34D which are vertically overlapped may be spot-welded and seamless. Welding, laser welding, etc., and joining the two together.

Further, in the inner pot 90, a sealing material 92 containing glass mud is provided inside the front end portion of the tube 38, and the opening of the tube 38 is sealed by the sealing material 92 to ensure airtightness in the sealed space 36.

Next, a method of manufacturing the inner pot 90 of the second embodiment will be described with reference to Fig. 12 .

As shown in Fig. 12(a), in the method of manufacturing the inner pot 90, first, the inner container 32 and the outer container 34 are formed by press working (draw processing) (pressing step). Moreover, in this press process, the connection recessed part 34F is also formed in the outer side bottom wall part 34A of the outer side container 34.

After the pressing step, as shown in Fig. 12(b), the upper portion of the outer side wall portion 34B of the outer container 34 is subjected to hole processing, and the outer container 34 is formed with a through hole 34E (drilling step).

After the drilling process, as shown in Fig. 12(c), the inner container 32 is disposed inside the outer container 34. Specifically, the inner bottom wall portion 32A of the inner container 32 is placed on the top of the coupling recess 34F of the outer container 34 to overlap the first flange 32D of the inner container 32 on the upper side of the second flange 34D of the outer container 34. Way of configuration. Then, the front end portion of the first flange 32D of the inner container 32 and the front end portion of the second flange 34D of the outer container 34 are laser welded to join the front end portions of the both sides (flange joining step). Thereby, the inner container 32 and the outer container 34 are coupled together, and a sealed space 36 is formed inside the inner pot 90.

Further, in the flange joining step, in addition to the joining of the front end portion of the first flange 32D and the front end portion of the second flange 34D, the vertical overlap of the first flange 32D and the second flange 34D may be overlapped. The part is joined to spot welding, seamless welding, laser welding, etc., and the two are joined (in the case of Fig. 12(c), an example of spot welding is shown). Further, in the case of laser welding, laser welding is performed from the upper side of the first flange 32D or the lower side of the second flange 34D, and the both are joined. In this case, when considering the design feeling of the inner pot 90, it is preferable to perform laser welding from the lower side of the second flange 34D.

As shown in Fig. 12(d), after the flange joining step, the upper and lower pair of guns for spot welding are placed in the upper side of the inner bottom wall portion 32A of the inner container 32 and the connecting recess 34F of the outer container 34, and passed through Spot welding joins the inner bottom wall portion 32A and the top portion of the coupling recess portion 34F (pot bottom joining step). Thereby, the inner bottom wall portion 32A of the inner container 32 and the outer bottom wall portion 34A of the outer container 34 are coupled together.

As shown in Fig. 12(e), after the pan-and-bottom joining step, the base end portion of the tube 38 is inserted into the through hole 34E of the outer container 34, and the base end portion of the tube 38 and the edge of the through hole 34E are arc-welded. Part joining (vacuum suction joining process). Thereby, the tube 38 is provided in the outer container 34, and the inside of the sealed space 36 and the outside of the inner pot 90 are connected by the tube 38.

As shown in Fig. 12(f), after the vacuum suction joining step, the inner peripheral surface of the inner container 32 is subjected to fluorine coating treatment to form a layer made of a fluororesin (Teflon), and the outer periphery of the outer container 34 is formed. The surface is subjected to a coating treatment to form a layer composed of a heat resistant paint (surface treatment step).

As shown in Fig. 12(g), after the surface treatment step, the working fluid 40 is injected into the sealed space 36 from the tube 38. Further, after the working fluid 40 is injected into the sealed space 36, the air in the sealed space 36 is discharged using a vacuum sealing device, and the sealing material 92 is used to seal the tube 38. Specifically, the air in the sealed space 36 is discharged by the vacuum pump of the vacuum sealing device, and when the air pressure in the sealed space 36 becomes equal to or lower than a predetermined value, the sealing material 92 is filled into the tube 38 by the vacuum sealing device. Further, the vacuum sealing device has a spiral-shaped induction coil, and the tube 38 is inserted into the induction coil. Then, by applying a high-frequency current to the induction coil, the tube 38 is locally inductively heated to melt the sealing material 92. Thereafter, the tube 38 is cooled to seal the tube 38 by the sealing material 92 (vacuum sealing process).

As shown in Fig. 12 (h), after the vacuum sealing step, the intermediate portion in the longitudinal direction of the tube 38 is cut (cutting step).

After the cutting step, as shown in Fig. 12(i), the pair of cover members 52 (cover 50) are assembled to the first flange 32D of the inner container 32 and the second flange 34D of the outer container 34 (cover assembly) Process).

As apparent from the above, the manufacture of the inner pot 90 is completed.

Further, the manufacturing process of the inner pot 90 may be performed in a vacuum environment state (vacuum chamber) after evacuation by a vacuum device. In this case, all the steps shown in Figs. 12(a) to (i) can be performed in a vacuum environment, and the pressing step shown in Fig. 12(a) and Fig. 12(b) are performed. The steps after the drilling process shown can also be carried out in a vacuum environment. Thereby, in the vacuum sealing process shown in Fig. 12(g), since the inner pot 90 is already in a vacuum environment, the step of evacuating can be omitted. In this case, the tube for vacuuming may be omitted in the outer container 34, and the metal plate material that covers (closes) the through hole 34E from the outside may be welded to the outer container 34 to perform vacuum sealing. Glass mud can also be used as a vacuum sealing material. Further, in this case, the working fluid 40 can be introduced into the sealed space 36 from the through hole 34E in a solid (ice) state. Therefore, the pipe for injecting the working fluid can be omitted.

Thereby, it is possible to manufacture the inner pot 90 which has no protrusions, such as a tube, in the inner container 32 or the outer container 34. Therefore, since the inner pot 90 has a structure without a tube, the inner pot 90 can be easily cleaned, the ease of use of the inner pot 90 can be further improved, and the design feeling of the inner pot 90 can be further improved.

Further, in the second embodiment, when the bottom of the inner pot 90 is heated, the working fluid 40 injected into the sealed space 36 is also heated. When the temperature of the heated working fluid 40 reaches the boiling point, the working fluid 40 is boiled, and a part of the working fluid 40 is vaporized. Then, the vaporized vapor rises along the inner corner portion 32C and the inner side wall portion 32B in the sealed space 36 toward the side portion 36C side in the sealed space 36. Thereby, the inner side wall portion 32B of the inner pot 90 is heated by the steam. Further, the vapor of the inner side wall portion 32B is heated and condensed, and the liquid is changed from the gas to the liquid as the working fluid 40. Further, the working fluid 40 that has become a liquid is lowered by its own weight, and returns to the bottom portion 36A of the sealed space 36. Further, in the working fluid 40, the inner side wall portion 32B of the inner container 32 is heated by repeating the above-described phase change cycle. As described above, in the inner pot 90 of the second embodiment, as in the first embodiment, the inner side wall portion 32B of the inner pot 90 can be efficiently heated, and the entire inner pot 90 can be heated substantially uniformly.

Further, in the inner pot 90 of the second embodiment, the plurality of connection concave portions 34F are formed in the outer bottom wall portion 34A of the outer container 34, and the connection concave portion 34F is joined to the inner bottom wall portion 32A of the inner container 32 by spot welding or the like. together. Thereby, the inner bottom wall portion 32A and the outer bottom wall portion 34A can be connected with a simple configuration. Further, compared with the first embodiment, the number of components can be reduced, and the number of manufacturing man-hours can be reduced.

Further, in the inner pot 90 of the second embodiment, the front end portion of the first flange 32D of the inner container 32 and the front end portion of the second flange 34D of the outer container 34 are joined by laser welding or the like. Further, the overlapping portions of the first flange 32D and the second flange 34D that are vertically overlapped are joined by spot welding, seamless welding, laser welding, or the like. Thereby, the joint strength of the first flange 32D and the second flange 34D can be improved, and the rigidity of the opening of the inner pot 90 can be improved. As a result, deformation of the inner container 32 can be suppressed during heating of the inner pot 90.

In other words, for example, in the joining (melting) of only the front end portion of the first flange 32D and the front end portion of the second flange 34D, the internal pressure of the sealed space 36 rises during heating of the inner pot 90, and the inner container It is possible that the 32 is deformed so as to be lifted from the front end portion of the first flange 32D. On the other hand, by joining the overlapping portions of the first flange 32D and the second flange 34D, the rigidity of the opening portion of the inner pot 90 is increased. As a result, deformation of the inner container 32 during heating of the inner pot 90 can be suppressed, and the joined state of the first flange 32D and the second flange 34D can be favorably maintained.

Further, in the second embodiment, the plurality of connection concave portions 34F are formed in the outer bottom wall portion 34A of the outer container 34. However, the one connection concave portion 34F may be formed in the outer bottom wall portion 34A. In this case, the connection concave portion 34F may be disposed at the center portion of the outer bottom wall portion 34A, and the top portion of the connection concave portion 34F and the central portion of the inner bottom wall portion 32A may be joined together.

(Third embodiment)

Next, an inner pot 100 as a "heating cooker" of the third embodiment will be described with reference to Fig. 13.

The inner pot 100 of the third embodiment is the same as the inner pot 30 of the first embodiment except for the aspects described below. In addition, in the thirteenth embodiment, the same components as those of the first embodiment are denoted by the same reference numerals. Further, in Fig. 13, the cover 50 is omitted from illustration in the inner pot 100.

In the third embodiment, the joint pin 42 of the first embodiment is omitted from the inner pot 100. Further, a deep drawing portion 32G that is raised upward is formed in the inner bottom wall portion 32A of the inner container 32. The deep portion 32G is formed in a substantially disk shape concentric with the inner bottom wall portion 32A, and the outer peripheral portion of the deep portion 32G is smoothly curved and connected to the inner bottom wall portion 32A. Further, as an example, the diameter of the deep drawing portion 32G is set to 60% of the diameter of the inner bottom wall portion 32A, and the drawing height of the deep portion 32G is set to 3 mm.

Further, a drawing portion 34G having the same configuration as the drawing portion 32G is formed in the outer bottom wall portion 34A of the outer container 34. In other words, the deep drawing portion 34G is formed in a substantially disk shape that is concentric with the outer bottom wall portion 34A, and is raised upward from the outer bottom wall portion 34A. Further, the outer peripheral portion of the deep drawing portion 34G is smoothly curved and connected to the outer bottom wall portion 34A. Further, as an example, the diameter of the deep drawing portion 34G is set to 60% of the diameter of the outer bottom wall portion 34A, and the drawing height of the deep portion 34G is set to 3 mm.

Further, in the third embodiment, as in the second embodiment, the lower flange portion 32D2 of the first embodiment is omitted in the first flange 32D of the inner container 32. Further, the first flange 32D (upper flange portion 32D1) of the inner container 32 and the second flange 34D of the outer container 34 are disposed to overlap each other, and the front end portion of the first flange 32D and the second outer container 34 are disposed. The front end portion of the flange 34D is joined by laser welding or the like. Further, the overlapping portions of the first flange 32D and the second flange 34D that are vertically overlapped are joined by spot welding or the like.

Further, in the third embodiment, when the bottom portion of the inner pot 100 is heated, the working liquid 40 injected into the sealed space 36 is also heated, and the phase change period of the working liquid 40 is repeated. Thus, in the inner pot 100 of the third embodiment, as in the first embodiment, the inner side wall portion 32B of the inner pot 100 can be efficiently heated, and the entire inner pot 100 can be heated substantially uniformly.

Further, in the third embodiment, the deep-drawn portion 32G that is raised upward is formed in the inner bottom wall portion 32A, and the deep-drawn portion 34G that is raised upward is formed in the outer bottom wall portion 34A. Therefore, the deep drawing portion 32G (draw portion 34G) functions as a reinforcing deep drawing of the inner bottom wall portion 32A (outer bottom wall portion 34A). Thus, when the bottom of the inner pot 100 is heated, the inner bottom wall portion 32A and the outer bottom wall portion 34A can be prevented from being bent (deformed) even if the internal pressure of the sealed space 36 is increased.

In this case, in the vertical direction, the inner bottom wall portion 32A and the outer bottom wall portion 34A are deflected (deformed) in the vertical direction when the inner portion of the sealed space 36 is pressed to 5 atm, which is assumed to be the maximum pressure during heating. The amount is explained. In other words, in the pot in which the deep bottom portion 32A and the outer bottom wall portion 34A are omitted, the deep bottom portion 32A and the deep bottom portion 34G are formed, and when the inner portion of the sealed space 36 is pressed to 5 atm, the inner bottom wall portion 32A and the outer side are formed. The amount of deflection (deformation) of the bottom wall portion 34A in the vertical direction was 2.4 mm. On the other hand, when the inner portion of the sealed space 36 of the pot 100 of the third embodiment is pressed to 5 atm, the amount of deflection (deformation) in the vertical direction of the inner bottom wall portion 32A and the outer bottom wall portion 34A is determined. 0.3mm. Thus, according to the inner pot 100 of the third embodiment, it is possible to suppress the deflection (deformation) of the inner bottom wall portion 32A and the outer bottom wall portion 34A when the bottom portion is heated.

Further, in the third embodiment, since the coupling pin 42 is omitted as compared with the first embodiment, the number of components can be reduced, and the inner bottom wall portion 32A and the outer bottom wall can be suppressed during heating of the pan 100. The deflection (deformation) of the portion 34A.

(About the deformation of the tube 38)

Next, the deformation of the tube 38 used in the inner pots 30, 60, 90, and 100 of the first embodiment (including the modified examples) to the third embodiment will be described using the inner pot 90 of the second embodiment.

(About the deformation of the tube 38)

As shown in Fig. 14 (A) and (B), in the deformation 1 of the tube 38, a plurality of (two in the present modification, two) tubes 38 are provided in the inner pot 90. In the two tubes 38 One pipe is configured to inject the working fluid 40 into the sealed space 36, and the other pipe 38 is configured as a pipe for evacuating the sealed space 36. In other words, in the first modification, the tube 38 for each manufacturing process of the inner pot 90 (injection process of the working fluid 40, vacuuming process) is provided. Thereby, the process of injecting the working fluid 40 into the sealed space 36 and the efficiency of the process of evacuating the sealed space 36 can be achieved.

Further, in the modification 1, the two tubes 38 are arranged at equal intervals (180 degrees apart) in the circumferential direction of the inner pot 90. That is, the two tubes 38 are disposed opposite to each other in the radial direction of the inner pot 90. Further, as a cover for the deformation 1 of the tube 38, a pair of tube covers 110 covering only the respective tubes 38 are provided in the inner pot 90 instead of the cover 50. The tube cover 110 is formed in a substantially rectangular plate shape in which the upper and lower directions are in the thickness direction. Further, the tube cover 110 is formed with a concave portion 110A that is open to the radially inner side of the inner pot 90, and the concave portion 110A is formed in a circular shape when viewed from the radial direction of the inner pot. Further, the tube 38 is fitted into the recess 110A, and the tube cover 110 is attached to the inner pot 90. Thereby, the tube cover 110 of the cover tube 38 can be utilized as a handle of the inner pot 90, and the tube 38 can be utilized as a mounting part (core part) of a handle (tube cover 110). Further, as described above, by arranging the two tubes 38 at equal intervals in the circumferential direction of the inner pot 90, the tube cover 110, which is a handle, can be disposed in a well-balanced manner. Therefore, the easy grip of the inner pot 90 can be improved, and the convenience for the user can be improved.

Further, in the modification 1, the two tubes 38 are provided in the inner pot 90, but three or more tubes 38 may be provided in the inner pot 90. Further, in this case, the number of the tubes 38 provided in the inner pot 90 may be set in consideration of the working time of the tube 38 (the injection working time of the working fluid 40 and the working time for vacuuming). For example, when the working time for vacuuming is longer than the injection time of the working fluid 40, the number of tubes 38 for vacuuming may be larger than the number of tubes 38 for injecting the working fluid 40. As an example, the number of the tubes 38 for injecting the working fluid 40 may be one, and the number of tubes 38 for vacuuming may be two. Thereby, the work time of using the tube 38 can be shortened, and the manufacturing time of the inner pot 90 can be shortened.

Further, in the modification 1, the diameters of the plurality of tubes 38 are set to be the same, but the diameters of the plurality of tubes 38 may be set to different sizes. In this case, similarly to the above, the diameter of the tube 38 provided in the inner pot 90 can be changed in consideration of the working time of the tube 38. For example, when the working time for evacuation is longer than the injection time of the working fluid 40, the diameter of the tube 38 for vacuuming may be larger than the diameter of the tube 38 for injection of the working fluid 40. Thereby, as in the above, the work time can be shortened.

Further, in the first modification, the plurality of (two) tubes 38 are disposed 180 degrees apart in the circumferential direction of the inner pot 90, but the positions of the plurality of tubes 38 in the circumferential direction of the inner pot 90 can be arbitrarily set. For example, a plurality of tubes 38 may be disposed at adjacent positions in the circumferential direction of the inner pot 90. Thereby, for example, it is possible to reduce the size of the working space when the respective tubes for injecting the working fluid and the vacuum are connected to the tube 38. Further, for example, it is possible to suppress the drag operation of the tube connected to each of the tubes 38, and the like, and it is possible to contribute to the reduction in the number of manufacturing man-hours of the inner pot 90.

(About the deformation of tube 38)

In the modification 2, the rest of the configuration is the same as the above-described modification 1 except for the aspects described below.

That is, as shown in Fig. 15, in the modification 2, the tube 38 is provided in the inner container 32. Specifically, the tube 38 projects (projects) from the inner side wall portion 32B of the inner container 32 toward the radially inner side of the inner pot 90. Further, a communication hole that communicates the inside of the tube 38 and the inside of the sealed space 36 is formed in the inner side wall portion 32B. Thus, in the deformation 2, since the tube 38 does not protrude outward in the radial direction of the inner pot 90, it is possible to suppress a decrease in the design feeling of the appearance of the inner pot 90. Further, since the tube 38 does not protrude outward in the radial direction of the inner pot 90, the inner pot 90 can be easily applied to the existing rice cooker. Therefore, the versatility of the inner pot 90 can be improved. Further, in the modification 2, similarly to the modification 1, a plurality of tubes 38 may be provided in the inner container 32.

Further, in the second modification, the position of the tube 38 in the vertical direction is set such that the tube 38 is located above the cooked rice (meter of the maximum rice cooking amount of the inner pot 90). Therefore, even if the tube 38 is configured to be disposed on the inner side wall portion 32B of the inner container 32, the contact between the cooked rice and the tube 38 can be suppressed.

In the inner pots 30, 60, 90, and 100 of the first embodiment (including the modified examples) to the third embodiment, water is used as the working fluid 40, but the type of the working fluid 40 injected into the sealed space 36 is used. Not limited to this. For example, the working fluid 40 may be ethylene glycol, eucalyptus oil, propylene glycol or the like.

In the first embodiment to the third embodiment, the height H of the bottom portion 36A of the sealed space 36 is set to 4 mm, but the size of the inner pot 30 is not changed, and the capacity of the inner pot 30 is increased. In view of this, it is considered that the inner bottom wall portion 32A is lowered to further lower the height dimension H. Further, when the height dimension H is further lowered (for example, when it is made 3 mm or less), it is preferable to set the volume ratio of the working fluid 40 of the sealed space 36 to the bottom portion 36A to 10 vol% to 80 vol%, and particularly preferably It is set to 30 vol% to 80 vol%.

On the other hand, in order to heat the inner side wall portion 32B of the inner pot 30 more efficiently, when the height dimension H is higher than 4 mm of the present embodiment, it is preferable to make the working fluid 40 of the sealed space 36 with respect to the bottom portion 36A. The volume ratio is set to 5 vol% to 80 vol%, and particularly preferably set to 8 vol% to 30 vol%.

Further, in the inner pots 30, 60, 90, 100 of the first embodiment (including the modified examples) to the third embodiment, since the inner pots 30, 60, 90, 100 are heated, the internal pressure of the sealed space 36 Since it is raised, a safety mechanism for preventing an abnormal rise in the internal pressure of the sealed space 36 may be provided in the inner pots 30, 60, 90, and 100. Next, this point will be described using the inner pot 90 of the second embodiment in Fig. 16.

As shown in Fig. 16 (A) and (B), a notch 32H constituting a safety mechanism is formed on the inner peripheral surface of the inner corner portion 32C of the inner container 32, and the notch 32H is along the inner container 32. The direction orthogonal to the circumferential direction is formed in a straight line shape. The notch 32H is formed in a substantially V-shaped groove shape that is open to the inside in the radial direction of the inner container 32, and the portion of the inner container 32 where the notch 32H is formed is the thin portion 32I (in a broad sense, it is a "fragile portion"). The elements of mastery). Therefore, in the inner container 32, the strength of the thin portion 32I is configured to be lower than the strength of the other portions.

In addition, the shape (depth and width) of the notch 32H is set such that the thin portion 32I is broken when the internal pressure of the sealed space 36 is larger than a predetermined value. Therefore, when the internal pressure of the sealed space 36 is larger than a predetermined value during heating of the inner pot 90, the thin portion 32I is broken, and the vapor in the sealed space 36 is directed from the broken portion to the lower portion of the inner pot 90 (detailed Say, configure the part of the meter) to spray. Therefore, the vapor can escape from the vapor tower of the lid portion 24 of the rice cooker 10 through the opening of the inner pot 90. Therefore, it is possible to suppress an abnormal rise in the internal pressure of the sealed space 36, and it is possible to improve the safety of the rice cooker 10.

Further, in the example shown in FIGS. 16(A) and 16(B), the notch 32H linearly extends in a direction orthogonal to the circumferential direction of the inner pot 90, but the extending direction of the notch 32H can be arbitrarily set. For example, the notch 32H may be formed to extend in the circumferential direction of the inner pot 90, and the notch 32H may be formed to extend obliquely with respect to the circumferential direction of the inner pot 90.

Further, in the example shown in FIGS. 16(A) and (B), one notch 32H is formed in the inner pot 90, but the number of the notches 32H may be plural.

Further, in the example shown in FIGS. 16(A) and 16(B), the cross-sectional shape of the notch 32H is formed in a substantially V-shaped groove shape, but the cross-sectional shape of the notch 32H can be appropriately changed. For example, the cross-sectional shape of the notch 32H may be formed into a substantially semicircular groove shape.

Further, in the above-described safety mechanism, the thin portion 32I is formed in the inner container 32, but the location where the thin portion 32I is formed can be arbitrarily set.

For example, a notch 32H may be formed in the tube 38, and a thin portion 32I may be formed on the tube 38. That is, as shown in Fig. 16(C), a single or a plurality of (two in the example shown in Fig. 16(C)) notches 32H may be formed on the outer peripheral portion of the tube 38, and on the tube 38. A thin portion 32I is formed.

Further, for example, the thin portion 32I may be formed on the upper portion of the inner side wall portion 32B (preferably above the rice of the maximum cooking amount of the inner pot 90). In this case, the thin portion 32I is disposed at a position away from the bottom portion of the inner pot 90 (i.e., the heated portion in the inner pot 90). Thereby, deterioration of the thin portion 32I can be suppressed. In particular, by arranging the thin portion 32I at a position above the rice of the maximum cooking amount of the inner pot 90, contact with the thin portion 32I after rice cooking can be suppressed.

Further, in the above-described safety mechanism, the thin portion 32I is formed in the inner container 32 (inner side wall portion 32B), but the thin portion 32I may be formed in the outer container 34 (outer side wall portion 34B) instead of being formed in the inner container 32. . Further, the thin portion 32I may be formed in the inner container 32 and the outer container 34. Further, when the thin portion 32I is formed in the inner container 32 and the outer container 34, for example, when the internal pressure of the sealed space 36 rises abnormally, even when one thin portion 32I is not broken, the other can be made The thin portion 32I is broken to allow the vapor to escape to the outside of the sealed space 36. Thereby, the safety of the rice cooker 10 can be further improved.

In addition, when the thin portion 32I is formed from the thickness of the inner container 32, a part of the inner container 32 (the inner side wall portion 32B) may be pressed during the press working of the inner container 32. It is flat and forms a thin portion 32I. For example, although the illustration is omitted, a circular recess that is flattened toward the inner side in the thickness direction may be formed on the inner peripheral surface or the outer peripheral surface of the inner side wall portion 32B, and the portion in which the recess is formed may be thin. Department 32I.

Further, at the time of press working of the inner container 32, a part of the inner container 32 (inner side wall portion 32B) may be half-punched to form a thin portion 32I. For example, although not shown in the drawings, a part of the inner side wall portion 32B may be half-punched to the radially inner side or the radially outer side, and the boundary portion of the half-punched portion may be the thin portion 32I.

Thereby, the thin portion 32I can be easily formed, and the inner pot 90 can be produced inexpensively. Further, similarly to the above, the concave portion or the half-cut portion may be formed in at least one of the inner container 32 and the outer container 34, and the position of the concave portion or the half-cut portion may be arbitrarily set.

In addition, when the internal pressure of the sealed space 36 rises abnormally and the vapor escapes to the outside of the sealed space 36, a safety valve may be provided in the inner container 32 or the outer container 34 (as an example). , the structure of the spring type safety valve). In this case, when the internal pressure of the sealed space 36 rises abnormally, the vapor can escape to the outside of the sealed space 36 without damaging the inner pot 90.

Further, in the first embodiment, the inner pot 30 is provided with a coupling pin 42, and the inner bottom wall portion 32A and the outer bottom wall portion 34A are coupled by the joint pin 42. Alternatively, as shown in Fig. 17, in the inner pot 30, the joint pin 42 (the center pin 44 and the outer peripheral pin 46) is omitted, and the inner bottom wall portion 32A and the outer bottom wall portion 34A are not connected to each other. .

In addition, in the inner pots 30, 60, 90, and 100 of the first embodiment (including the modified examples) to the third embodiment, the inner side wall portion 32B and the outer side container of the inner container 32 may be omitted. A coupling pin 42 is provided between the outer side wall portions 34B of 34, and the inner side wall portion 32B and the outer side wall portion 34B are coupled by a coupling pin 42. In this case, the joint pin 42 is disposed in the radial direction of the inner pots 30, 60, 90, and 100 in the axial direction, and the inner side wall portion 32B and the outer side wall portion 34B are coupled by the joint pin 42. Thereby, deformation of the inner side wall portion 32B and the outer side wall portion 34B during heating of the inner pots 30, 60, 90, and 100 can be suppressed.

Further, in this case, a plurality of coupling pins 42 may be provided between the inner side wall portion 32B of the inner container 32 and the outer side wall portion 34B of the outer container 34, and the inner pots 30, 60, 90, 100 The circumferential direction is configured at equal intervals. Thereby, deformation of the inner side wall portion 32B and the outer side wall portion 34B during heating of the inner pans 30, 60, 90, and 100 can be suppressed, and between the inner side wall portion 32B and the outer side wall portion 34B of the sealed space 36 can be realized. Homogenization of the gap. As a result, in the circumferential direction of the inner pots 30, 60, 90, and 100, unevenness in the amount of vapor rising between the inner side wall portion 32B and the outer side wall portion 34B can be suppressed. Therefore, the inner side wall portion 32B can be uniformly heated in the circumferential direction of the inner container 32.

Further, in the first embodiment (including modifications) to the third embodiment, the inner pots 30, 60, 90, and 100 include the cover 50, but the inner pots 30, 60, 90, and 100 may be used. The structure of the cover 50 is omitted.

Further, in the cover 50 of the first embodiment (including the modified example) to the third embodiment, the portion covering the first flange 32D and the second flange 34D of the inner pots 30, 60, 90, 100 and the covering tube Part of the 38 is formed into a ring shape. Alternatively, the cover 50 may be formed to be integrally formed by an annular portion covering the entire circumference of the first flange 32D and the second flange 34D and a portion covering only the tube 38 (i.e., the above-described tube cover 110). Into the shape. In this case, the welded portion of the first flange 32D and the second flange 34D and the tube 38 can be covered in an unrecognizable manner.

Further, in the inner pot 30 (60) of the first embodiment (including the modified example), the first flange 32D of the inner container 32 is wound around the outer container 34 in the opening portion of the inner pot 30 (60). The flange 34D is folded back and forth to ensure the airtightness of the sealed space 36. However, the structure for ensuring the airtightness of the sealed space 36 is not limited thereto.

For example, as shown in Fig. 18, the second flange 34D may be formed to be folded back 180 degrees toward the radially inner side of the inner pots 30, 60, and the first flange 32D of the inner container 32 is wound after folding. The second flange 34D is constructed in a manner. That is, in this case, the second flange 34D has a superposed structure in which the upper and lower sides are overlapped. Further, the upper flange portion 32D1 and the lower flange portion 32D2 of the first flange 32D press the second flange 34D having the overlapping structure up and down. Thereby, the airtightness of the sealed space 36 can be ensured, and the rigidity of the opening of the inner pot 30 (60) can be improved.

Further, in the first embodiment (including the modified examples) to the third embodiment, the inner peripheral surface of the inner container 32 is subjected to Teflon processing, but the surface treatment of the inner peripheral surface of the inner container 32 is not limited to this. . For example, all or a part of the inner circumferential surface of the inner container 32 (for example, only the inner bottom wall portion 32A or only the inner side wall portion 32B) may be roughened, and the inner circumferential surface of the inner container 32 may be formed in a concavo-convex shape. . For example, the inner peripheral surface of the inner container 32 may be subjected to a diamond coating treatment. Further, for example, the inner peripheral surface of the inner container 32 may be subjected to sandblasting, and after the sandblasting, Teflon processing may be performed. Thereby, irregularities are formed on the inner circumferential surface of the inner container 32. Therefore, when the rice is cooked, relatively fine bubbles are generated in the inner pot by the unevenness. As a result, the rice in the inner pot can be uniformly heated by the generation of the bubbles.

Further, in the first embodiment (including the modified example) to the third embodiment, in order to raise the vapor generated in the sealed space 36 well, the outer surface of the inner container 32 and the inner surface of the outer container 34 are mirror-finished. Although the treatment is performed, it is also possible to roughen the outer side surface of the inner container 32 and the inner side surface of the outer container 34 from the viewpoint of easily generating vapor in the sealed space 36 during heating of the inner pot. For example, the outer side surface of the inner container 32 and the inner side surface of the outer container 34 may be sandblasted to form the outer side surface of the inner container 32 and the inner side surface of the outer container 34 in an uneven shape.

Further, in the inner pots 30, 60, 90, and 100 of the first embodiment (including the modified examples) to the third embodiment, the thickness of the inner container 32 and the thickness of the outer container 34 are set to be the same, but The thickness of the inner container 32 and the thickness of the outer container 34 are set to be different. For example, the thickness of the inner container 32 may be set to be smaller than the thickness of the outer container 34, and may be configured to promote heating of the inner container 32. Further, by setting the thickness of the inner container 32 to be smaller than the thickness of the outer container 34, the heat of the vapor vaporized by the working fluid 40 in the sealed space 36 can be made to the inner pots 30, 60, 90, 100. The inner side wall portion 32B efficiently dissipates heat to the inside of the inner pots 30, 60, 90, 100.

Further, in the first embodiment (including the modified examples) to the third embodiment, the thicknesses of the inner container 32 and the outer container 34 are set to be uniform (constant) as a whole, but the inner container 32 and the outer container 34 may be provided. The plate thickness is set to be uneven. For example, in the inner container 32, the thickness of the inner side wall portion 32B may be set to be smaller than the thickness of the inner bottom wall portion 32A to promote heating of the inner side wall portion 32B. In this case, the thickness of the inner corner portion 32C of the inner container 32 may be set to gradually become thinner from the inner bottom wall portion 32A toward the inner side wall portion 32B.

Further, in the first embodiment (including the modified examples) to the third embodiment, the inner container 32 and the outer container 34 are made of a magnetic material (stainless steel). Alternatively, the inner container 32 may be made of a high thermal conductor such as copper or aluminum. In this case as well, when the inner pans 30, 60, 90, and 100 are heated, the inner container 32 can be efficiently heated.

Further, the inner container 32 may be molded by using a precoated steel sheet or the like whose surface is precoated with a fluorine resin. Thereby, the manufacturing process of the inner pots 30, 60, 90, and 100 can be shortened.

Further, in the first embodiment (including modifications) to the third embodiment, the inner pots 30, 60, 90, 100 are applied to the IH type rice cooker 10, but the rice cookers 30, 60, 90, 100 are not used. Limited to this. For example, the heating unit 16 of the rice cooker 10 may be changed to a heater, and the inner pots 30, 60, 90, and 100 may be heated by the heater.

(note)

As described above, the present invention has been described in terms of efficiently heating the side wall of the heating cooker in a heating cooker having a double-wall structure having a closed space therein, but from another viewpoint, it may be as follows I understand that.

In other words, in the heating cooker described in the background art, when the working fluid is injected into the sealed space and the bottom of the heating cooker is heated, the working fluid boils, and the vapor vaporized from the working fluid is sealed. The side of the space rises. Thereby, the side wall of the inner side of the heating cooker is heated by steam. Further, the vapor of the side wall is heated and condensed to become a liquid as a working fluid, and the working fluid which becomes a liquid falls by its own weight, and returns to the bottom of the sealed space. Further, in the working fluid, the side portion of the heating cooker is heated by repeating the above-described phase change cycle.

However, in the above-described heating cooker, there is still room for improvement in the following aspects. In other words, in the above-described heating cooker, as described above, when the bottom of the heating cooker is heated, the vapor vaporized from the working fluid rises along the side portion of the sealed space. Further, by continuously heating the heating cooker, the air pressure (pressure) in the sealed space rises. Therefore, the bottom portion in the closed space expands, and the bottom of the heating cooker may be deformed. Therefore, in a heating cooker having a sealed space therein, it is desirable to have a structure capable of suppressing deformation of the heating cooker due to expansion.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a heating cooker capable of suppressing expansion at the time of heating.

A first aspect of the present invention provides a heating cooker which is formed in a bottomed cylindrical shape and has a double-wall structure having a sealed space therein, and includes a bottomed cylindrical inner container constituting the heating cooker An inner side portion; a bottomed cylindrical outer container constituting an outer portion of the heating cooker; a working fluid injected into the sealed space; and a connecting portion disposed in the sealed space to allow the inner container The inner bottom wall portion is coupled to the outer bottom wall portion of the outer container.

According to a second aspect of the invention, in the heating cooker according to the first aspect, the connecting portion is formed by a connecting pin extending in an axial direction of the heating cooker.

According to a third aspect of the present invention, in the heating cooker according to the second aspect, the connecting pin is disposed at a center portion of the heating cooker in a plan view as seen from an opening side of the heating cooker.

According to a fourth aspect of the invention, in the heating cooker according to the first aspect of the invention, the connecting portion radially protrudes from a center of the heating cooker when viewed in a plan view from an opening side of the heating cooker.

According to a fifth aspect of the present invention, in the heating cooker according to the fourth aspect of the present invention, a communication hole that allows the sealed space partitioned by the connecting portion to communicate with each other is formed at a lower end portion of the connecting portion.

In summary, the technical means disclosed by the present invention can effectively solve the problems of the prior knowledge, achieve the intended purpose and efficacy, and are not found in the publication before publication, have not been publicly used, and have long-term progress, The invention referred to in the Patent Law is correct, and the application is filed according to law, and the company is invited to give a detailed examination and grant a patent for invention.

The above is only the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, that is, the equivalent changes and modifications made by the scope of the invention and the contents of the invention are all It should remain within the scope of this invention.

〔this invention〕

10‧‧‧Electric rice cooker

12‧‧‧ rice cooker main body

14‧‧‧Inner pot storage

16‧‧‧ heating department

18‧‧‧Power Supply Department

20‧‧‧ Temperature sensor

22‧‧‧Control Department

24‧‧‧ 盖部

26‧‧‧Hinged mechanism

30‧‧‧Inner pot (heating cooker)

32‧‧‧ inside container

32A‧‧‧Inside bottom wall

32B‧‧‧Inside side wall

32C‧‧‧ inside corner

32D‧‧‧First flange

32D1‧‧‧Upper flange

32D2‧‧‧ lower flange

32G‧‧‧Drawing Department

32H‧‧‧ gap

32I‧‧‧ Thin wall

34‧‧‧Outside container

34A‧‧‧Outer bottom wall

34B‧‧‧Outside side wall

34C‧‧‧Outer corner

34D‧‧‧second flange

34E‧‧‧through hole

34F‧‧‧ Connection recess

34G‧‧‧Drawing Department

36‧‧‧Confined space

36A‧‧‧ bottom

36B‧‧‧ bottom

36C‧‧‧ side

38‧‧‧ tube

38A‧‧‧Riveting

40‧‧‧ working fluid

42‧‧‧Links

44‧‧‧Center Sales

46‧‧‧Weekly sales

50‧‧ hood

52‧‧‧ Cover parts

52A‧‧‧peripheral wall

52B‧‧‧Upper wall

52C‧‧‧Bottom wall

52D‧‧‧Intermediate wall

52E‧‧‧First Storage Department

52F‧‧‧Second Storage Department

52G‧‧‧ buckle

52H‧‧‧Clocks

52J‧‧‧ snap hole

60‧‧‧ inner pot (heating cooker)

62‧‧‧floor

70‧‧‧Link board

70A‧‧‧Links

70B‧‧‧Connected holes

72‧‧‧First link board

74‧‧‧Second link board

80‧‧‧Intermediate board

90‧‧‧ inner pot (heating cooker)

92‧‧‧ Sealing material

100‧‧‧ inner pot (heating cooker)

110‧‧‧ tube cover

110A‧‧‧ recess

H‧‧‧ Height dimensions at the bottom of confined spaces

R‧‧‧ Radius of the inside corner

W‧‧‧width dimensions of confined spaces

Fig. 1 is a longitudinal sectional view of the inner pot of the first embodiment (an enlarged cross-sectional view taken along line 1-1 of Fig. 2).

Fig. 2 is a plan view of the inner pot of the first embodiment as seen from the upper side.

Fig. 3 is an enlarged cross-sectional view showing, in an enlarged manner, a half of the inner pot shown in Fig. 1.

Fig. 4 is a partially cutaway plan view showing the cover shown in Fig. 1 as seen from the upper side.

Fig. 5 is a longitudinal sectional view showing a rice cooker to which the inner pot shown in Fig. 1 is applied.

Fig. 6 is a graph showing temperature data of the inner pot and the rice when the rice is cooked using the inner pot shown in Fig. 1.

Fig. 7 is a graph showing temperature data of the inner bottom wall portion and the outer side wall portion of the inner pot when the inner pot is cooked using the inner pot shown in Fig. 1, and the working liquid phase in the closed space is made to the bottom. The graph represented by the case when the volume ratio has changed. Fig. 7(A) shows a case where the volume ratio of the working fluid is set to 3 vol%, Fig. 7(B) shows a case where the volume ratio of the working fluid is set to 10 vol%, and Fig. 7(C) shows the working fluid. The volume ratio was set to 85 vol%.

Fig. 8 is an explanatory view for explaining the rise of the vapor in the side portion of the sealed space when the inner pot shown in Fig. 1 is heated.

Fig. 9 is a vertical cross-sectional view corresponding to Fig. 1 showing a modification of the inner pot shown in Fig. 1.

Fig. 10(A) is a perspective view showing an example of deformation of the connection between the inner bottom wall portion and the outer bottom wall portion shown in Fig. 1, and Fig. 10(B) is a view showing the inner bottom wall portion and the outer bottom wall portion. A perspective view of another variant of the link.

Fig. 11(A) is a longitudinal sectional view of the inner pot of the second embodiment (a cross-sectional view taken along line 11A-11A of Fig. 11(B)), and Fig. 11(B) is a view of Fig. 11(A). Bottom view of the inner pot.

Fig. 12 is an explanatory view for explaining a method of manufacturing the inner pot shown in Fig. 11.

Fig. 13 is a longitudinal sectional view showing the inner pot of the third embodiment.

Fig. 14(A) is a longitudinal sectional view of the inner pot for explaining the deformation 1 of the tube shown in Fig. 11 (cross-sectional view taken along line 14A-14A of Fig. 14(B)), Fig. 14 (B) ) is a bottom view of the inner pot shown in Fig. 14(A).

Fig. 15 is a longitudinal sectional view of the inner pot for explaining the deformation 2 of the tube shown in Fig. 11.

Fig. 16(A) is a longitudinal sectional view showing an example in which a notch is formed in the inner pot shown in Fig. 11, and Fig. 16(B) is an enlarged cross-sectional view showing the notch shown in Fig. 16(A) ( Figure 16 (A) is an enlarged sectional view of line 16B-16B). Fig. 16(C) is a partial longitudinal sectional view showing an example in which the notch of Fig. 16(A) is formed in a tube.

Fig. 17 is a vertical cross-sectional view corresponding to Fig. 1 in another modification in which the connecting pin is omitted in the inner pot shown in Fig. 1.

Fig. 18 is a partial longitudinal sectional view showing a modification of the first flange of the inner container and the second flange of the outer container shown in Fig. 1.

Claims (8)

A heating cooker is formed in a bottomed cylindrical shape and has a double-wall structure having a closed space inside, and is characterized by comprising: a bottomed cylindrical inner container constituting an inner portion of the heating cooker; a bottomed cylindrical outer container constituting an outer portion of the heating cooker; a working fluid that is injected into the confined space, The amount of the working fluid in the sealed space is set to an amount that does not cover the entire bottom surface of the sealed space. The heating cooker according to claim 1, wherein The volume ratio of the working liquid phase to the bottom portion of the closed space is set to 4 vol% to 80 vol%. The heating cooker according to claim 1 or 2, wherein In the longitudinal section, the height of the sealed space at the bottom of the heating cooker is set to be equal to or larger than the width dimension of the closed space of the side portion of the heating cooker, and is set to 2 mm or more. The heating cooker according to claim 1 or 2, wherein The negative pressure or vacuum of 0.01 standard atmospheric pressure or less is maintained in the sealed space. The heating cooker according to claim 4, wherein Provided in an inner side wall portion of the inner container or an outer side wall portion of the outer container, when the working fluid is injected into the sealed space and when the sealed space is made into a negative pressure or a vacuum Multiple tubes. The heating cooker according to claim 5, wherein A plurality of tubes are disposed at equal intervals in the circumferential direction of the heating cooker, and a tube cover covering the tubes is attached to the tubes. The heating cooker according to claim 1 or 2, wherein An inner corner portion that is curved toward the outer side of the inner container is formed between the inner bottom wall portion and the inner side wall portion of the inner container, The radius of the inner corner portion is set to gradually decrease as going from the inner bottom wall portion to the inner side wall portion. The heating cooker according to claim 1 or 2, wherein The surface of the inner container that constitutes the sealed space and the surface of the outer container that constitutes the sealed space are mirror-finished.