TWI683642B - 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.

The following Patent Document 1 describes a heating tube-type heating cooker. The heating cooker has a double-wall structure with an enclosed space inside, and a working fluid is injected into the enclosed space. Furthermore, when the bottom of the heating cooker is heated, the working fluid boils, and vaporized vapor in the working fluid rises along the side of the closed space. Thus, the inner side wall of the heating cooker is heated by steam. Furthermore, the vapor heated by the side wall condenses and turns into a liquid as a working fluid. The working fluid that has become a liquid drops by its own weight and returns to the bottom of the enclosed space. Furthermore, by repeating the above-mentioned phase change cycle of the working fluid, the heating cooker is heated.

Existing technical literature

Refer to Patent Document 1: Japanese Patent No. 2713008

In view of this, our inventors are devoted to further research and embarked on research and development and improvement, with a better design to solve the above problems, and after continuous testing and modification, the invention came out.

Problems to be solved by the invention

However, in the above-mentioned heating cooker, there is room for improvement in the aspects shown below. That is, in the heating cooker described above, the amount of the working fluid in the closed space for efficiently heating the inner side wall of the heating cooker is not specified.

The present invention has been made in consideration of the above facts, and an object of the present invention is to provide a heating cooker that can efficiently heat the side wall inside the heating cooker.

Technical solutions for solving problems

Aspect 1: One or more embodiments of the present invention provide a heating cooker that is formed into a bottomed cylindrical shape and presents a double-wall structure with an enclosed space inside, characterized by having: a bottomed cylindrical inner side A container which constitutes the inner part of the heating cooker; a bottomed cylindrical outer container which constitutes the outer part of the heating cooker; and a working fluid which is injected into the enclosed space, the enclosed space The amount of the working fluid inside is set to an amount that does not cover the entire bottom surface of the enclosed space.

Aspect 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 of the closed 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 the height dimension of the closed space at the bottom of the heating cooker is set to the heating cooker in longitudinal section The width of the sealed space on the side of the device is greater than or equal to 2 mm.

Aspect 4: One or more embodiments of the present invention provide a heating cooker characterized by maintaining a negative pressure or vacuum of 0.01 standard atmospheric pressure (atm) or less in the enclosed space.

Aspect 5: One or more embodiments of the present invention provide a heating cooker characterized in that the working fluid is provided on the inner side wall portion of the inner container or the outer side wall portion of the outer container A plurality of tubes used when injecting into the enclosed space and when making the enclosed space into negative pressure or vacuum.

Aspect 6: One or more embodiments of the present invention provide a heating cooker characterized in that a plurality of tubes are arranged at equal intervals in the circumferential direction of the heating cooker, and the tubes are installed to cover the tubes Tube cover.

Aspect 7: One or more embodiments of the present invention provide a heating cooker, characterized in that a curvature is formed between the inner bottom wall portion and the inner side wall portion of the inner container toward the outer side of the inner container A convex inner corner, the radius of the inner corner is set to gradually decrease as it goes from the inner bottom wall to the inner side wall.

Aspect 8: One or more embodiments of the present invention provide a heating cooker characterized by implementing the surface of the inner container constituting the sealed space and the surface of the outer container constituting the sealed space Mirror processing.

Invention effect

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

Regarding the technical means of our inventors, a few preferred embodiments and drawings are described in detail below, in order to provide a deep understanding and recognition of the present invention.

(First embodiment)

Next, the inner pot 30 as the "heating cooker" of the first embodiment will be described using 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 be described first, and then the structure of the inner pot 30 will be described. In addition, the arrow UP appropriately shown in the drawing indicates the upper side of the rice cooker 10 and the inner pot 30. In addition, in the following description, when showing the up-down direction, the up-down directions of the rice cooker 10 and the inner pot 30 are 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 body 12 and a lid 24.

＜About rice cooker main body 12＞

The rice cooker body 12 has an inner pot storage portion 14 for storing an inner pot 30 described later. The inner pot accommodating portion 14 has a concave shape that opens upward, and is formed in a substantially circular shape when viewed from the top. A heating portion 16 for heating the inner pot 30 is provided below the inner pot storage portion 14. The heating unit 16 is composed of an induction coil which is wound in a substantially spiral shape under the inner pot storage unit 14.

In addition, a power supply unit 18 is provided below the heating unit 16, and a high-frequency current is added to the heating unit 16 (induction coil) through the power supply unit 18. Thus, by applying a high-frequency current to the heating unit 16 (induction coil), an eddy current is generated in the inner pot 30 described later, and the inner pot 30 starts to generate heat due to the resistance in the inner pot 30. In addition, a temperature sensor 20 is provided below the central portion of the inner pot storage portion 14. The temperature sensor 20 is configured as a sensor that measures the temperature of the bottom of the inner pot 30. Furthermore, a control unit 22 electrically connected to the power supply unit 18 and the temperature sensor 20 is provided on the upper portion of the rice cooker body 12. Furthermore, the control unit 22 controls the power supply unit 18 based on the output signal from the temperature sensor 20.

<About the lid 24>

The lid portion 24 is rotatably connected to the upper portion of the rice cooker body 12 via a hinge mechanism 26 and covers the opening of the inner pot storage portion 14. In addition, it is configured that by opening the lid portion 24 from this state, the opening of the inner pot storage portion 14 is opened and closed, so that the inner pot 30 described later can be stored in the inner pot storage portion 14.

(About inner pot 30)

As shown in FIGS. 1 to 3, the inner pot 30 is formed into a substantially bottomed cylindrical shape that opens upward, and has a double-wall structure having a sealed space 36 inside. 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. In addition, the working fluid 40 is injected into the closed space 36 of the inner pot 30. Furthermore, the inner pot 30 includes: a connection pin 42 (in a broad sense, an element grasped as a “connection part”) that connects the inner container 32 and the outer container 34, and a cover that covers the flange formed in the opening of the inner pot 30 50. Next, each structure of the inner pot 30 is demonstrated.

<About inner container 32>

The inner container 32 is composed of a magnetic body (in this embodiment, as an example, stainless steel), and is formed into a substantially bottomed cylindrical shape that opens upward. Specifically, the inner container 32 is composed of an inner bottom wall portion 32A constituting the bottom of the inner container 32, a cylindrical inner side wall portion 32B constituting the side portion of the inner container 32, and a connection between the inner bottom wall portion 32A and the inner side wall portion 32B The inner corner 32C is configured. The inner bottom wall portion 32A is formed in a substantially disc shape with the plate thickness direction in the up-down direction. In addition, in a longitudinal cross-sectional view, the inner bottom wall portion 32A gradually slopes slightly downward from the center portion toward the radially outer side. In other words, the inner bottom wall portion 32A is formed by being slightly curved so that the central portion of the inner bottom wall portion 32A is convex upward.

When viewed in a longitudinal section, the inner corner 32C bends into a substantially quarter ellipse so as to project outward of the inner container 32 (radially outward and downward to the inner container 32), and smoothly smoothes the inner bottom wall The outer peripheral end of the portion 32A is connected to the lower end of the inner side wall portion 32B. Specifically, in longitudinal section, the radius R of the inner corner 32C is set to gradually decrease from the outer peripheral end of the inner bottom wall 32A to the lower end of the inner side wall 32B. That is, the radius R1 corresponding to the outer peripheral end of the inner bottom wall portion 32A is set larger than the radius R2 corresponding to the lower end of the inner side wall portion 32B.

In the opening of the inner side wall portion 32B, a first flange 32D extending radially outward of the inner container 32 is formed, 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 opened radially inward of the inner container 32. Specifically, the first flange 32D includes an upper flange portion 32D1 formed by bending the opening end portion of the inner side wall portion 32B toward the radial outer side of the inner container 32 by approximately 90 degrees, and the upper flange portion 32D1 The front end portion of the lower flange portion 32D2 is formed by folding back approximately 180 degrees toward the radial inner side of the inner container 32. In addition, between the upper flange portion 32D1 and the lower flange portion 32D2, a second flange 34D of the outer container 34 described later is arranged, and the second flange 34D is joined to the first flange 32D.

In addition, a layer made of a heat-resistant processed fluororesin product, here 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 closed space 36) was subjected to a mirror surface treatment.

<About outer container 34>

Like the inner container 32, the outer container 34 is composed of a magnetic body (in this embodiment, as an example, stainless steel), and is formed into a substantially bottomed cylindrical shape that opens upward. Specifically, the outer container 34 is composed of an outer bottom wall portion 34A constituting the bottom of the outer container 34, a cylindrical outer side wall portion 34B constituting the side portion of the outer container 34, and an outer peripheral end portion connecting the outer bottom wall portion 34A and the outer side The outer corner 34C of the lower end of the side wall 34B is configured. In addition, in the present embodiment, the plate thicknesses of the inner container 32 and the outer container 34 are set to be the same, and the entire inner container 32 and the outer container 34 are set to a uniform (constant) plate 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 so as to be coaxial with the inner container 32 radially outward of the inner side wall portion 32B. In addition, the outer bottom wall portion 34A is formed in a circular flat plate shape whose upper and lower directions are in the plate thickness direction, and is disposed below the inner bottom wall portion 32A of the inner container 32. That is, when the inner pot 30 is stored in the inner pot storage portion 14 of the rice cooker 10, the outer bottom wall portion 34A is in close contact with the bottom surface of the inner pot storage portion 14. In addition, similar to the inner bottom wall portion 32A of the inner container 32, the outer bottom wall portion 34A may be slightly curved so that the central portion of the outer bottom wall portion 34A is convex upward.

The outer corner 34C, like the inner corner 32C, is curved into a substantially quarter ellipse so as to be convex toward the outside of the outer container 34 (downward and radially outward of the outer container 34) in longitudinal section. , 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 longitudinal section, the radius of the inner corner 32C is set to gradually decrease from the outer peripheral end of the outer bottom wall 34A to the lower end of the outer side wall 34B.

At the opening end of the outer side wall portion 34B, a second flange 34D protruding radially outward is formed. The second flange 34D is bent approximately 90 degrees radially outward of the outer container 34 at the opening end of the outer side wall portion 34B, and extends over the entire circumference of the outer side wall portion 34B. Furthermore, 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, is press-contacted by the first flange 32D, and is joined to both. That is, at the time of molding the first flange 32D, the first flange 32D is bent so 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. Thus, the outer container 34 is assembled to the inner container 32, and a substantially U-shaped closed space 36 that opens upward in a longitudinal section is formed between the inner container 32 and the outer container 34. In addition, the front end portion of the first flange 32D is joined to the second flange 34D by arc welding or the like. In addition to the joining of the front end portion of the first flange 32D and the second flange 34D, spot welding may be performed on the overlapping portions of the first flange 32D and the second flange 34D that overlap in the vertical direction, seamlessly Welding, laser welding, etc., and the two are joined together. As a result, the airtightness of the enclosed space 36 is ensured. Furthermore, the inner surface of the outer container 34 (the surface constituting the closed space 36) was subjected to a mirror surface treatment.

Here, the enclosed space 36 will be described.

As described above, the closed space 36 is formed into a substantially hollow U shape when viewed in longitudinal section. Furthermore, in the present embodiment, the bottom 36A of the sealed space 36 is set to a region (space) below the inner surface of the inner bottom wall portion 32A of the inner container 32 (refer to FIGS. 1 and 3). The area indicated by the two-dot chain line L1 is further down). Therefore, in the present embodiment, the inner surface of the outer container 34 constituting the bottom 36A of the enclosed space 36 is the bottom surface 36B of the enclosed space 36, and the bottom surface 36B is defined by the inner surface of the outer bottom wall portion 34A of the outer container 34 and the outer corner Part of the inner surface of the portion 34C is configured.

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

In the enclosed space 36, the height dimension H of the bottom 36A of the enclosed space 36 (the vertical dimension between the inner bottom wall portion 32A and the outer bottom wall portion 34A, see FIG. 3) is set to the side portion 36C of the enclosed 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) or more is set to 2 mm or more. In this embodiment, the height H of the bottom 36A is set to 4 mm, and the width W of the side 36C is set to 2 mm. In addition, 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 H of the bottom 36A to 10 mm or less. In addition, since the inner bottom wall portion 32A is slightly curved so that its central portion is convex upward as described above, the height dimension H changes in the radial direction of the inner pot 30. Therefore, in this embodiment, the height dimension H is set to 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 enclosed space 36 is exaggerated for convenience.

Returning to the description of the outer container 34, a circular through hole 34E is formed in the upper portion of the outer side wall portion 34B of the outer container 34 and at the position below the second flange 34D. In addition, at 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 injecting the working fluid 40 and the vacuum for the sealed space 36 into the sealed space 36 described later is provided. The tube 38 and the through hole 34E are arranged 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 tube 38 protruding from the outer side wall portion 34B to the radially outer side of the inner pot 30 connects the inside of the sealed space 36 with the outside of the inner pot 30.

Furthermore, in the present embodiment, the working fluid 40 is injected into the sealed space 36 from the tube 38. In addition, after the working fluid 40 is injected into the enclosed space 36, a vacuum pump (not shown) is installed in the tube 38, and the air in the enclosed space 36 is exhausted by the vacuum pump, and the enclosed space 36 becomes negatively maintained at less than 0.1 atm Setting of pressure (more preferably a negative pressure of 0.01 atm or less) or vacuum. In addition, the tube for injecting the working fluid 40 and the tube for vacuum evacuation do not need to be common, and may be installed separately.

A crimped portion 38A is formed at the front end of the tube 38, and the front end of the tube 38 is blocked by the crimped portion 38A. Specifically, while the air in the enclosed space 36 is discharged by a vacuum pump, the front end portion of the tube 38 is riveted, and the riveted portion 38A is formed by cutting the riveted portion. In addition, the caulking portion 38A is flattened up and down, and is formed into a substantially plate shape with the plate thickness direction up and down. Furthermore, the front end portion of the caulking portion 38A is sealed by arc welding or the like. Thus, the airtightness of the enclosed space 36 is ensured.

＜About working fluid 40＞

In this embodiment, water is used as the working fluid 40. Then, the working fluid 40 is injected into the sealed space 36 from the tube 38 described above, and stored in the bottom 36A of the sealed space 36. In addition, the volume ratio of the working fluid 40 in the closed space 36 to the bottom 36A is set to 4 vol% to 80 vol%. That is, in the storage state of the working fluid 40, the entire bottom 36A of the sealed space 36 is not immersed in water through the working fluid 40, but is above the bottom 36A of the sealed space 36 and between the working fluid 40 and the inner bottom wall portion 32A There is a gap between them. More specifically, in the present embodiment, the amount of the working fluid 40 in the sealed space 36 is set so that the working fluid 40 does not cover the entire bottom surface 36B of the bottom 36A of the sealed space 36. As a result, in a state where the working fluid 40 is disposed on the bottom surface 36B of the closed space 36, a plurality of droplet-shaped working fluid 40 are dispersedly disposed on the bottom surface 36B. In addition, in the present embodiment, as described above, the volume ratio of the working fluid 40 of the closed space 36 to the bottom 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 7vol% to 15vol%, and particularly preferably 8vol% to 12vol%.

＜About connecting pin 42＞

The connecting pin 42 is composed of a magnetic body (in this embodiment, as an example, stainless steel). The connecting pin 42 is formed in a substantially cylindrical shape with the axial direction up and down, and connects the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pot 30 together. Specifically, the connecting pin 42 includes a center pin 44 that connects the central portion of the inner bottom wall portion 32A and the central portion of the outer bottom wall portion 34A, and an outer peripheral portion that connects the outer peripheral portion of the inner bottom wall portion 32A and the outer peripheral bottom portion 34A A plurality of (in this embodiment, four) outer peripheral pins 46 are configured. Furthermore, the outer peripheral pins 46 are arranged at regular intervals (every 90 degrees) at the circumferential direction of the inner pot 30.

In addition, in the present embodiment, the upper end portion of the connecting 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 assembling the inner container 32 and the outer container 34, the lower end of the connecting pin 42 is joined to the outer bottom wall portion 34A of the outer container 34 from the outside of the outer container 34 by laser welding or the like. In addition, in the present embodiment, the connecting pin 42 is composed of the center pin 44 and the outer peripheral pin 46. However, in the connecting pin 42, the outer peripheral pin 46 may be omitted, and only the connecting pin 42 is the center pin 44.

＜About cover 50＞

As shown in FIGS. 1, 3, and 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 made of heat-resistant resin (in this embodiment, as an example, heat-resistant ABS). In addition, in a plan view, the cover 50 is divided into two, and is composed of a pair of cover members 52. The pair of cover members 52 have a semicircular shape (substantially C-shape) that opens toward the center side of the inner pot 30 in a plan view, and is formed to face the inner pot 30 in a cross-sectional view seen from the circumferential direction (longitudinal direction). A concave shape that opens radially inward. Specifically, the cover member 52 includes an outer peripheral wall 52A constituting an outer peripheral portion of the cover member 52, an upper wall 52B extending radially inward of the cover member 52 from an upper end portion of the outer peripheral wall 52A, and a lower end portion of the outer peripheral wall 52A The lower wall 52C projecting radially inward of the cover member 52 is configured. In addition, between the upper wall 52B and the lower wall 52C, there are formed a pair of upper and lower intermediate walls 52D extending radially inward from an intermediate portion in the vertical direction of the outer peripheral wall 52A, and the intermediate wall 52D is disposed to be aligned with the upper wall 52B and the lower wall 52C Parallel, extending in the circumferential direction of the cover member 52.

The upper portion inside the cover member 52 (the space between the upper intermediate wall 52D and the upper wall 52B) is the first storage portion 52E. In addition, the first flange 32D of the inner pot 30 is fitted into the first storage portion 52E, so that the cover member 52 is fixed to the inner pot 30. In other words, the cover member 52 covers the first flange 32D (including the second flange 34D) of the inner pot 30 from the outside in the radial direction. In addition, the lower portion inside the cover member 52 (the space between the lower intermediate wall 52D and the lower wall 52C) is used as the second storage portion 52F. In addition, the tube 38 of the inner pot 30 is stored in the second storage portion 52F. Thus, the tube 38 is covered by the cover member 52 from the radially outer side of the inner pot 30.

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

In addition, as the fixing of the cover member 52 to the inner pot 30, the above-mentioned buckle 52G and the engaging piece 52H may be omitted, and only a structure in which the first flange 32D is fitted into the first storage portion 52E may be adopted. In addition, the cover member 52 may be coupled and fixed to the first flange 32D with screws, rivets, or the like to fix the cover member 52 to the inner pot 30. Furthermore, the cover 50 is not limited to being divided into two, and a structure in which the cover 50 is divided into three or more may be adopted.

(Function and effect)

Next, the operation and effect of this embodiment will be described.

When cooking rice using the inner pot 30 and the rice cooker 10 configured as described above, the inner pot 30 is stored in the inner pot storage portion 14 of the rice cooker 10, and the bottom of the inner pot 30 is heated by the heating portion 16 of the rice cooker 10. Specifically, by applying a high-frequency current to the heating unit 16 (induction coil), an eddy current is generated in the inner pot 30. As a result, the bottom of the inner pot 30 starts to generate heat, and the working fluid 40 in the closed 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 vaporizes. The vaporized vapor instantaneously diffuses into the enclosed space 36 to heat the inner side wall portion 32B of the inner pot 30. Then, the vapor after heating the inner side wall portion 32B of the inner pot 30 starts to condense, and changes from gas to liquid as the working fluid 40. The working fluid 40 after becoming liquid returns to the bottom 36A of the closed space 36 by its own weight. In addition, in the working fluid 40, by repeating the cycle of the phase change described above, the inner side wall portion 32B of the inner pot 30 is heated, 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 enclosed 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 kept from time to time The temperature of the inner container 32 rises while heating stagnation and substantially uniformly.

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

Moreover, as shown in the figure, it can be seen that the temperature of the inner side wall portion 32B of the inner pot 30 and the inner bottom of the inner pot 30 from the start of cooking to the start of the "rice cooking section" that starts approximately 20 minutes later The temperature of the wall portion 32A rises to 100°C equally. In addition, it can be seen that even in the "rice cooking section" and "steamed rice section" after the temperature of the inner pot 30 reaches 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.

Furthermore, it can be seen that at the beginning of the “rice cooking section”, the temperatures of the upper and lower portions of the rice increase as the temperatures of the inner side wall portion 32B and the inner bottom wall portion 32A of the inner pot 30 increase. 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 the rice can be cooked.

In addition, in the present embodiment, it has been found that even in the so-called quick rice cooking in which the "soaking section" in rice cooking is omitted and the rice is immediately cooked as the "rice cooking section" from the beginning of cooking, it can be done in a short time Proceed to cooking. That is, in the case of normal quick rice cooking, in order to prevent excessive evaporation of the rice-soaking water (hereinafter referred to as "soak water") in the quick rice cooking, the rice cooker 10 is heated during the rice cooking process The control that the output of the section 16 (induction coil) is lowered relative to the output at the start of cooking. Therefore, during the rice cooking process, the above-mentioned output is temporarily lowered, so that the time until the rice cooking is completed for the rapid rice cooking is correspondingly extended.

On the other hand, it has been found that in the case of rapid rice cooking using the inner pot 30 of the present embodiment, it is possible to suppress excessive evaporation of the soaking water in the rapid rice cooking. Therefore, it has been confirmed that even if the output to the heating portion 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 will be cooked no less than by normal cooking. The cooked rice is inferior. Thus, by setting the output to the heating portion 16 (induction coil) of the rice cooker 10 to a constant output from the beginning to the end of cooking, the time for rapid rice cooking can be further shortened.

Here, in the inner pot 30 of the present embodiment, the volume ratio of the working fluid 40 of the closed space 36 to the bottom 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 closed space 36 in a drop shape so as not to cover the entire bottom surface 36B of the closed space 36. Thus, the inner side wall portion 32B of the inner container 32 can be efficiently heated.

Next, 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 36A is changed during cooking of the inner pot 30. In each graph of FIG. 7, the horizontal axis represents the time (minutes) from the start of cooking rice, and the vertical axis represents the temperature (° C.). In addition, the solid line of each graph is the measurement data of the upper part of the inner side wall part 32B of the inner pot 30, the broken line is the measurement data of the lower part of the inner side wall part 32B, and the dotted line is the center of the inner bottom wall part 32A of the inner pot 30 The double-dot chain line is the measurement data of the outer peripheral portion of the inner bottom wall portion 32A. Furthermore, in FIG. 7 (A), the volume ratio is set to 3 vol%, in FIG. 7 (B), the volume ratio is set to 10 vol%, and in FIG. 7 (C), the volume is set to The ratio is 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, although a phase change cycle of the working fluid 40 occurs (from the liquid to vaporize to become vapor, and from the vapor to condense and Return to the liquid cycle), but the behavior of the temperature rise of the entire inner pot 30 is unstable.

In addition, 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 steam decreases, and the gap between the inner bottom wall portion 32A and the inner side wall portion 32B of the inner pot 30 As the temperature difference increases, the temperature uniformity of the entire inner pot 30 cannot be 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 performs a phase transition cycle of steam well, and the inner pot 30 is suppressed. The temperature rises in the state of the temperature difference between the inner bottom wall portion 32A and the inner side wall portion 32B, and the entire inner pot 30 is heated substantially uniformly.

As can be seen from the above, by setting the volume ratio of the working fluid 40 of the closed space 36 to the bottom 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 heated substantially uniformly 30 overall heating.

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

That is, it has been found that when the height dimension H is set to be smaller than the width dimension W and less than 2 mm, the working fluid 40 that condenses and returns to liquid during the phase transition period of the working fluid 40 flows from the side 36C of the sealed space 36 toward The return efficiency of the bottom 36A will decrease, and the effect of uniformly heating the inner pot 30 will decrease. Therefore, as described above, by setting the height dimension H to be greater than the width dimension W to 2 mm or greater, it is possible to suppress the return of the working fluid 40 that has condensed and returned to liquid from the side 36C of the sealed space 36 to the bottom 36A The efficiency is reduced, and the effect of uniformly heating the inner pot 30 can be improved. From the above, it can be seen that the inner side wall portion 32B of the inner container 32 can be heated more efficiently.

Furthermore, the inside of the enclosed space 36 may be maintained at a negative pressure of less than 0.1 atm (more preferably a negative pressure of 0.01 atm or less) or a vacuum setting. 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 steam generated in the enclosed 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 exceeding 0.1 atm is formed in the enclosed space 36, the residual air A (refer to the part indicated by the two-dot chain line) in the enclosed space 36 rises along the inner side wall portion 32B The steam is pushed toward the upper end of the sealed space 36. That is, in this case, the residual air A in the enclosed space 36 becomes a resistance layer against the steam when the steam rises, and tends to hinder the steam rise. In addition, by making the enclosed space 36 a negative pressure state of less than 0.1 atm, the resistance of the remaining air A to the steam to be raised can be reduced, and the steam can be raised to the upper end side of the enclosed space 36 to pass the steam well The inner side wall portion 32B is heated. In addition, by maintaining the negative pressure or vacuum within 0.01 atm or less in the enclosed space 36, the inner side wall portion 32B can be heated more favorably by steam. Therefore, by setting the inside of the enclosed space 36 to maintain a negative pressure of less than 0.1 atm (more preferably a negative pressure of 0.01 atm or less) or vacuum, the inner side wall portion 32B of the inner container 32 can be heated more satisfactorily.

In addition, the radius R of the inner corner portion 32C of the inner pot 30 is set so as to gradually decrease from the outer peripheral end portion of the inner bottom wall portion 32A to the lower end portion of the inner side wall portion 32B. That is, the radius R1 corresponding to the outer peripheral end of the inner bottom wall portion 32A is set larger than the radius R2 corresponding to the lower end of the inner side wall portion 32B. Thereby, it is possible to suppress the reduction in the capacity of the inner pot 30 (the amount of rice that can be cooked), and it is possible to efficiently make the steam generated in the enclosed space 36 to the inner side wall portion 32B side along the inner corner portion 32C of the inner pot 30 rise. This point will be described below.

That is, without changing the radial size of the inner pot 30, and assuming that the radius R of the inner corner portion 32C is set to the radius R1 corresponding to the outer peripheral end portion of the inner bottom wall portion 32A and set to be constant (Hereinafter, this case is referred to as a comparative example.) The lower portion of the inner corner portion 32C enters radially inner side than the present embodiment. That is, the diameter of the inner bottom wall portion 32A is reduced. Therefore, in the comparative example, the capacity of the inner pot 30 tends to decrease.

In addition, in the comparative example, the angle of inclination of the tangent line tangent to the inner corner 32C with respect to the horizontal direction gradually increases in the radial direction outward of the inner container 32 in the longitudinal section.

In contrast, in the present embodiment, the radius R of the inner corner 32C of the inner container 32 is set to gradually decrease from the outer periphery of the inner bottom wall 32A to the lower end of the inner side wall 32B. Therefore, in a longitudinal cross-sectional view, the inclination angle of the tangent to the inner corner 32C with respect to the horizontal direction increases more sharply than the comparative example as it goes radially outward of the inner container 32. In other words, the inner corner portion 32C is formed so as to rise more sharply than the comparative example. This makes it possible to reduce the resistance to the steam rising along the inner corner portion 32C of the inner pot 30 compared to the comparative example, and it is possible to efficiently raise the steam to the inner side wall portion 32B side.

In addition, in the present embodiment, the lower end portion of the inner corner portion 32C can be arranged 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 that of the comparative example.

As can be seen from the above, according to the inner pot 30 of the present embodiment, it is possible to suppress the reduction in the capacity of the inner pot 30 and efficiently make the vapor in the enclosed space 36 follow the inner corner 32C of the inner container 32 toward the inner side wall The 32B side rises.

Furthermore, the surface of the inner pot 30 that constitutes the closed space 36 is subjected to a mirror surface treatment. Therefore, in the enclosed space 36, the resistance of these walls to the steam when the steam rises along the inner corner portion 32C and the inner side wall portion 32B of the inner pot 30 can be reduced. Thus, the vapor in the sealed space 36 can be favorably raised toward 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 these walls to the working fluid 40 when the working fluid 40 that has condensed and turned into a liquid drops. This makes it possible to return the working fluid 40 to the bottom 36A of the closed space 36 satisfactorily.

In addition, a connection pin 42 is provided in the closed space 36 of the inner pot 30, and the connection pin 42 connects the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pot 30 together. In addition, when the inner pot 30 is heated, the air pressure in the enclosed space 36 rises, and the inner bottom wall portion 32A and the outer bottom wall portion 34A expand up and down. At this time, since the inner bottom wall portion 32A and the outer bottom wall portion 34A are connected by the connecting pin 42, the inner bottom wall portion 32A and the outer bottom wall portion 34A function by the connecting pin 42 so as to stretch each other. Thereby, the expansion of the inner bottom wall portion 32A upward and the outer bottom wall portion 34A downward expansion during heating of the inner pot 30 by the connecting pin 42 can be suppressed, and the deformation of the bottom of the inner pot 30 can be suppressed .

Furthermore, the connecting pin 42 is composed of a pin whose axial direction is vertical. Therefore, in the bottom portion 36A of the closed space 36, the inner bottom wall portion 32A and the outer bottom wall portion 34A can be connected by the connecting pin 42 without hindering the flow of the working fluid 40 and the vapor that becomes gas.

In addition, the connecting pin 42 has 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 of the inner pot 30 together. Therefore, the connecting pin 42 can suppress the vertical displacement of the center portions of the inner bottom wall portion 32A and the outer bottom wall portion 34A. Thereby, at the time of expansion, the displacement of the portion with the largest displacement amount can be suppressed for 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.

Furthermore, the outer side wall portion 34B of the inner pot 30 is provided with a tube 38 protruding radially outward of the inner pot 30. Furthermore, before the crimping portion 38A of the tube 38 is formed, the inside of the closed space 36 of the inner pot 30 and the outside of the inner pot 30 are communicated by the tube 38. Thus, the working fluid 40 can be easily injected into the closed space 36 using the tube 38. In addition, by installing a vacuum pump in the tube 38, the air in the sealed space 36 can be discharged from the tube 38, so that the sealed space 36 can be brought into a negative pressure or vacuum state. Therefore, the workability at the time of manufacturing the inner pot 30 can be improved.

In addition, in the inner pot 30, the first flange 32D (second flange 34D) and the tube 38 of the inner pot 30 are covered by the cover 50 from the radially outer side of the inner pot 30. Therefore, even if the tube 38 which improves the workability at the time of manufacturing the inner pot 30 is provided in the outer side wall portion 34B, the tube 38 cannot be recognized by the cover 50. In addition, the cover 50 can be utilized as a handle of the inner pot 30. As can be seen from the above, not only can the design sense of the inner pot 30 be improved, but also the user's convenience can be improved.

Furthermore, 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 second flange 34D of the outer container 34 by hemming or the like. That is, the overlapping part of the inner container 32 and the outer container 34 is closed by a so-called labyrinth structure (labyrinth structure). Thereby, the airtightness in the enclosed space 36 formed by the inner container 32 and the outer container 34 can be ensured.

In addition, in the present embodiment, as described above, the inner pot 30 has a double-wall structure having a sealed space 36 inside, and the sealed space 36 becomes 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 modified example will be described using 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 addition, in FIG. 9, parts having the same configuration as in the first embodiment are given 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 to be solid. 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. In addition, 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, with respect to the inner corner portion 32C of the inner container 32 and the outer corner portion 34C of the outer container 34, a substantially solid disc-shaped bottom plate 62 is provided radially inward of the inner pot 60. Like the inner container 32 and the outer container 34, the bottom plate 62 is composed of a magnetic body (in this case, as an example, stainless steel). 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.

Thus, 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. In addition, a part of the inner pot 60 (the part between the inner corner 32C and the outer corner 34C) constitutes the bottom 36A of the sealed space 36. In addition, in the inner pot 60, since the bottom of the inner pot 60 is constituted by the bottom plate 62, the coupling pin 42 of the inner pot 30 of the present embodiment is omitted.

Furthermore, in the inner pot 60 of the modified example, when the bottom (bottom plate 62) of the inner pot 60 is heated, the working fluid 40 injected into the closed 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 part 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 enclosed space 36 to the side portion 36C side in the enclosed space 36. Thus, the inner side wall portion 32B of the inner pot 60 is heated by steam. In addition, the vapor heated by the inner side wall portion 32B is condensed and changes from gas to liquid as the working fluid 40. Furthermore, the working fluid 40 that has become a liquid drops by its own weight and returns to the bottom 36A of the closed space 36. In addition, in the working fluid 40, by repeating the cycle of the phase change described above, the inner side wall portion 32B of the inner pot 30 is heated. As can be seen from the above, even in the inner pot 60 of the modified example, as in the first embodiment, the inner side wall portion 32B of the inner pot 60 can be efficiently heated.

In the inner pot 60 of the modification, the bottom 36A of the sealed space 36 is set in the corner of the inner pot 60. Therefore, when the working fluid 40 is vaporized into vapor, the vapor can be immediately moved (ascended) to the side 36C side of the sealed space 36 along the inner corner 32C. Therefore, it is possible to efficiently move (rise) the vaporized vapor to the side portion 36C of the sealed space 36 to heat the inner side wall portion 32B of the inner pot 60.

Further, in the inner pot 60 of the modification, the sealed space 36 of the inner pot 60 becomes a space between the inner corner 32C and the inner side wall 32B and the outer corner 34C and the outer side wall 34B, but the sealed space 36 may also be It is set as the space between the outer corner 34C and the outer side wall 34B. In other words, the sealed space 36 only needs to include at least the space between the outer corner 34C and the outer side wall 34B. In this case, the lower portion of the inner pot 60 that is closer to the two-dot chain line L2 in FIG. 9 has a solid structure.

(A 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 connection method of the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pot 30 will be described.

(Variation 1 of connection method)

Next, a modification 1 of the connection method will be described using FIG. 10(A). In Modification 1, except for the following points, the rest of the configuration is the same as the first embodiment. In addition, in FIG. 10(A), members having the same configuration as in the first embodiment are given the same reference numerals.

That is, in Modification 1, the connecting pin 42 is omitted, and a connecting plate 70 (broadly speaking, grasped as a "connecting part" is provided between the inner bottom wall portion 32A and the outer bottom wall portion 34A of the inner pot 30 Elements). The coupling plate 70 is formed in a substantially cross shape in a plan view. Specifically, the coupling plate 70 is composed of a first coupling plate 72 and a pair of second coupling plates 74. The first connection plate 72 and the second connection plate 74 are formed in a substantially elongated plate shape, and the length of the first connection plate 72 in the longitudinal direction is set to approximately twice the length of the second connection plate 74 in the longitudinal direction. In addition, the one end portion in the longitudinal direction of the second connecting plate 74 is joined to the center portion in the longitudinal direction of the first connecting plate 72, so that the second connecting plate 74 extends from the center portion in the longitudinal direction toward the thickness direction of the first connecting plate 72. Side out. As a result, the coupling plate 70 has four coupling pieces 70A, and the coupling piece 70A extends radially from the central portion of the coupling plate 70.

Further, in a plan view, the coupling plate 70 is arranged on the inner bottom wall portion 32A and the outer bottom wall portion such that the central portion of the coupling 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. In addition, 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. Thus, the inner bottom wall portion 32A and the outer bottom wall portion 34A are connected by the connecting plate 70. In this state, the bottom 36A of the closed space 36 is separated by the connecting plate 70.

Furthermore, a plurality of communication holes 70B are formed in the lower end portion of each connecting piece 70A of the connecting plate 70. Thus, the bottom 36A of the closed 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 36A can flow in the bottom 36A of the partitioned closed space 36.

Furthermore, in the first modification, as described above, the inner bottom wall portion 32A and the outer bottom wall portion 34A are connected together by the connecting plate 70. Therefore, as in 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 addition, in the first modification, the connecting piece 70A of the connecting plate 70 extends radially 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, when the inner pot 30 is heated, the heat transferred to the coupling plate 70 can be transferred across the radial direction of the inner bottom wall portion 32A through the coupling piece 70A. Thereby, in the radial direction of the inner bottom wall portion 32A, the inner bottom wall portion 32A can be heated substantially uniformly by the connecting piece 70A.

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

In addition, in Modification 1, four connection pieces 70A are formed on the connection plate 70, but the number of connection pieces 70A can be arbitrarily set.

(Variation 2 of connection method)

Next, a modification 2 of the connection method will be described using FIG. 10(B). In Modification 2, the structure is the same as that of the first embodiment except for the following points. In addition, in FIG. 10(B), members having the same configuration as in the first embodiment are given the same reference numerals.

That is, in Modification 2, a substantially disc-shaped intermediate plate 80 is provided between the coupling pin 42 and the inner bottom wall portion 32A of the inner pot 30. The intermediate plate 80 is similar to the coupling pin 42 by a magnetic body (in this modification In the example, stainless steel is used as an example. That is, in Variation 2, the intermediate plate 80 is interposed between the connecting pin 42 and the inner bottom wall portion 32A of the inner pot 30, and the intermediate plate 80 is joined to the connecting pin 42 and the inner bottom wall portion 32A. Therefore, when the inner pot 30 is heated, the heat transferred by the connecting pin 42 is dispersed by the intermediate plate 80 and transferred to the entire inner bottom wall portion 32A of the inner pot 30. Thereby, in the modification 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 using 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 following points. In addition, in FIG. 11, parts having the same configuration as in the first embodiment are given the same reference numerals. In addition, in FIG. 11, in the inner pot 90, the cover 50 is omitted from illustration.

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 arranged substantially horizontally (along the outer container 34 along a plane orthogonal to the vertical direction) The outer bottom wall portion 34A is substantially parallel). In addition, in the inner pot 90, the connecting pin 42 of the first embodiment is omitted, and a plurality of (three in this embodiment) connecting recesses 34F (in a broad sense) are formed in the outer bottom wall portion 34A of the outer container 34 , Is an element grasped as a "connecting part"). The coupling recess 34F is formed into a substantially inverted U-shaped recess that opens downward when viewed in longitudinal section, and projects upward from the outer bottom wall portion 34A. In addition, the three coupling recesses 34F are arranged radially outward of the inner pot 90 with respect to the central portion of the outer bottom wall portion 34A, and are arranged at regular intervals (every 120 degrees) in the circumferential direction of the inner pot 90. Moreover, the top of the coupling recess 34F is arranged 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. Thus, the inner bottom wall portion 32A and the outer bottom wall portion 34A are connected together by the connecting recess 34F. In addition, as described above, in the second embodiment, the inner bottom wall portion 32A of the inner container 32 is arranged substantially horizontally along a plane orthogonal to the vertical direction, but as in the first embodiment, the inner side The bottom wall portion 32A is slightly curved upward.

In addition, 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 arranged to overlap with each other, and the front end portion of the first flange 32D and the second flange of the outer container 34 The front end portions of the flange 34D are joined together by laser welding or the like. 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, spot welding can also be performed on the overlapping portion of the first flange 32D and the second flange 34D that overlaps vertically, seamlessly Welding, laser welding, etc., and the two are joined together.

Furthermore, 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 the airtightness in the enclosed space 36.

Next, the method of manufacturing the inner pot 90 of the second embodiment will be described using 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 processing (drawing processing) (press process). In addition, in this press step, the connecting recess 34F is also formed on the outer bottom wall portion 34A of the outer container 34.

After the stamping process, as shown in FIG. 12( b ), the upper side wall portion 34B of the outer container 34 is bored to form a through hole 34E in the outer container 34 (drilling process).

After the drilling process, as shown in FIG. 12( c ), the inner container 32 is arranged inside the outer container 34. Specifically, the inner bottom wall portion 32A of the inner container 32 is placed on top of the coupling recess 34F of the outer container 34 so as 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 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, and the front end portions of both are joined (flange joining step). As a result, the inner container 32 and the outer container 34 are connected together, and a sealed space 36 is formed inside the inner pot 90.

In addition, in the flange joining step, in addition to the joining of the front end portions of the first flange 32D and the front end portions of the second flange 34D, the top and bottom of the first flange 32D and the second flange 34D may be overlapped vertically. The part is welded by spot welding, seamless welding, laser welding, etc., and the two are joined (in FIG. 12(c), an example of spot welding is shown). In addition, 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 two are joined. In this case, when considering the design sense 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, a pair of upper and lower guns for spot welding are arranged in the upper side of the inner bottom wall portion 32A of the inner container 32 and in the connecting recess 34F of the outer container 34 through Spot welding joins the inner bottom wall portion 32A and the top of the connection recess 34F (pot bottom joining step). Thus, the inner bottom wall portion 32A of the inner container 32 and the outer bottom wall portion 34A of the outer container 34 are connected together.

As shown in FIG. 12(e), after the pot 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 connected by arc welding Part bonding (vacuum suction port bonding process). Thus, the outer container 34 is provided with a tube 38, and the inside of the sealed space 36 and the outside of the inner pot 90 are communicated by the tube 38.

As shown in FIG. 12(f), after the vacuum suction port joining step, the inner peripheral surface of the inner container 32 is subjected to a fluorine coating process to form a layer made of fluororesin (Teflon), and to the outer periphery of the outer container 34 The surface is coated to form a layer made of 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. In addition, after the working fluid 40 is injected into the sealed space 36, the air in the sealed space 36 is exhausted using a vacuum sealing device, and the tube 38 is sealed using the sealing material 92. Specifically, the air in the enclosed space 36 is discharged by the vacuum pump of the vacuum sealing device, and when the air pressure in the enclosed space 36 becomes below a predetermined value, the tube 38 is filled with the sealing material 92 by the vacuum sealing device. In addition, 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 heated by induction, and the sealing material 92 is melted. Thereafter, the tube 38 is cooled to seal the tube 38 with the sealing material 92 (vacuum sealing step).

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

After the cutting step, as shown in FIG. 12(i), a 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 can be seen from the above, the manufacture of the inner pot 90 is completed.

In addition, 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 also be performed in a vacuum environment, and the stamping step shown in FIG. 12(a) and FIG. 12(b) are performed. The processes after the drilling process shown can also be performed in a vacuum environment. Thus, in the vacuum sealing process shown in FIG. 12(g), since the inner pot 90 is already in a vacuum environment, the process of evacuating can be omitted. In this case, a tube for evacuation may be omitted in the outer container 34, and a metal plate covering (closing) the through hole 34E from the outer side may be welded to the outer container 34 to perform vacuum sealing. Glass mud can also be used as a vacuum sealing material. In addition, in this case, the working fluid 40 can be thrown into the sealed space 36 from the through-hole 34E in a solid (ice) state, and therefore the tube for working fluid injection can be omitted.

This makes it possible to manufacture the inner pot 90 having no protrusions such as tubes in the inner container 32 or the outer container 34. Therefore, since the inner pot 90 has a tubeless structure, the inner pot 90 can be easily cleaned, the usability of the inner pot 90 can be made superior, and the design sense of the inner pot 90 can be further improved.

Furthermore, in the second embodiment, when the bottom of the inner pot 90 is heated, the working fluid 40 injected into the closed 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 part of the working fluid 40 vaporizes. Then, the vaporized vapor rises along the inner corner portion 32C and the inner side wall portion 32B in the enclosed space 36 to the side portion 36C side in the enclosed space 36. Thus, the inner side wall portion 32B of the inner pot 90 is heated by steam. In addition, the vapor heated by the inner side wall portion 32B is condensed and changes from gas to liquid as the working fluid 40. Furthermore, the working fluid 40 that has become a liquid drops by its own weight and returns to the bottom 36A of the closed space 36. In addition, in the working fluid 40, the inner side wall portion 32B of the inner container 32 is heated by repeating the above phase change cycle. As can be seen from the 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 to heat the entire inner pot 90 substantially uniformly.

In the inner pot 90 of the second embodiment, the outer bottom wall portion 34A of the outer container 34 is formed with a plurality of connecting recesses 34F, and the connecting recess 34F is joined to the inner bottom wall portion 32A of the inner container 32 by spot welding or the like. together. Thus, the inner bottom wall portion 32A and the outer bottom wall portion 34A can be connected with a simple structure. In addition, compared with the first embodiment, the number of parts can be reduced, and the number of manufacturing man-hours can be reduced.

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 together by laser welding or the like. Furthermore, the overlapping portions of the first flange 32D and the second flange 34D that overlap one another are joined together 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, when the inner pot 90 is heated, the deformation of the inner container 32 can be suppressed.

That is, for example, when only the front end portion of the first flange 32D and the front end portion of the second flange 34D are joined (welded) to each other, when the inner pot 90 is heated, the internal pressure of the enclosed space 36 rises, and the inner container The 32 may be deformed so as to lift up from the front end of the first flange 32D as a starting point. On the other hand, by joining the overlapping portions of the first flange 32D and the second flange 34D, the rigidity of the opening of the inner pot 90 is increased. As a result, the 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 maintained well.

In addition, in the second embodiment, the plurality of coupling recesses 34F are formed in the outer bottom wall portion 34A of the outer container 34, but one coupling recess 34F may be formed in the outer bottom wall portion 34A. In this case, the coupling recess 34F may be arranged at the center of the outer bottom wall 34A, and the top of the coupling recess 34F and the center of the inner bottom wall 32A may be joined together.

(Third embodiment)

Next, the inner pot 100 as the "heating cooker" of the third embodiment will be described using 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 following points. In addition, in FIG. 13, parts having the same configuration as in the first embodiment are given the same reference numerals. In addition, in FIG. 13, the inner pot 100 is shown with the cover 50 omitted.

In the third embodiment, the connecting pin 42 of the first embodiment is omitted on the inner pot 100. In addition, a drawn portion 32G that swells upward is formed on the inner bottom wall portion 32A of the inner container 32. The drawn portion 32G is formed in a substantially disc shape concentric with the inner bottom wall portion 32A, and the outer peripheral portion of the drawn portion 32G is smoothly curved and connected to the inner bottom wall portion 32A. In addition, as an example, the diameter of the drawn portion 32G is set to 60% of the diameter of the inner bottom wall portion 32A, and the drawn height of the drawn portion 32G is set to 3 mm.

In addition, a drawn portion 34G having the same configuration as the drawn portion 32G is formed on the outer bottom wall portion 34A of the outer container 34. That is, the drawn portion 34G is formed in a substantially disc shape concentric with the outer bottom wall portion 34A, and swells upward from the outer bottom wall portion 34A. In addition, the outer peripheral portion of the deep-drawn portion 34G is smoothly curved and connected to the outer bottom wall portion 34A. Further, as an example, the diameter of the drawn portion 34G is set to 60% of the diameter of the outer bottom wall portion 34A, and the drawn height of the drawn portion 34G is set to 3 mm.

In the third embodiment, as in the second embodiment, the lower flange portion 32D2 of the first embodiment is omitted from the first flange 32D of the inner container 32. Furthermore, the first flange 32D (upper flange portion 32D1) of the inner container 32 and the second flange 34D of the outer container 34 are arranged to overlap with each other, and the front end portion of the first flange 32D and the second flange of the outer container 34 The front end of the flange 34D is joined by laser welding or the like. In addition, the overlapping portions of the first flange 32D and the second flange 34D that overlap one another are joined by spot welding or the like.

Furthermore, in the third embodiment, when the bottom of the inner pot 100 is heated, the working fluid 40 injected into the closed space 36 is also heated, and the phase change cycle of the working fluid 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.

In the third embodiment, the deep drawing portion 32G raised upward is formed in the inner bottom wall portion 32A, and the deep drawing portion 34G raised upward is formed in the outer bottom wall portion 34A. Therefore, the deep drawing portion 32G (the deep drawing portion 34G) functions as a deep drawing for reinforcement of the inner bottom wall portion 32A (the outer bottom wall portion 34A). Thus, when the bottom of the inner pot 100 is heated, even if the internal pressure of the enclosed space 36 rises, it is possible to suppress the deflection (deformation) of the inner bottom wall portion 32A and the outer bottom wall portion 34A.

Next, for this point, when the internal pressure in the enclosed space 36 is assumed to be 5 atm, which is the maximum pressure during heating, the vertical deflection (deformation) of the inner bottom wall portion 32A and the outer bottom wall portion 34A is used. Quantity. That is, it has been found that in the pot in which the deep drawing portion 32G and the deep drawing portion 34G are omitted in the inner bottom wall portion 32A and the outer bottom wall portion 34A, when the inner pressure in the enclosed space 36 is made 5 atm, the inner bottom wall portion 32A and the outer side The amount of deflection (deformation) in the vertical direction of the bottom wall portion 34A is 2.4 mm. On the other hand, when the internal pressure in the enclosed space 36 of the pan 100 of the third embodiment is made 5 atm, the amount of vertical deflection (deformation) of the inner bottom wall portion 32A and the outer bottom wall portion 34A is 0.3mm. Thus, according to the inner pot 100 of the third embodiment, it is possible to suppress deflection (deformation) of the inner bottom wall portion 32A and the outer bottom wall portion 34A when the bottom portion is heated.

In addition, in the third embodiment, as compared with the first embodiment, the connecting pin 42 is omitted, so that the number of parts can be reduced, and the inner bottom wall portion 32A and the outer bottom wall during heating of the pan 100 can be suppressed. Deflection (deformation) of the part 34A.

(About deformation of tube 38)

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

(About deformation of tube 38 1)

As shown in FIGS. 14(A) and (B), in the modification 1 of the tube 38, a plurality of (in this modification 1, 2) tubes 38 are provided on the inner pot 90. Of the 2 tubes 38, One tube is configured to inject the working fluid 40 into the closed space 36, and the other tube 38 is configured to evacuate the closed space 36. That is, in the present modification 1, a tube 38 is provided for each manufacturing process of the inner pot 90 (injecting process of the working fluid 40, vacuuming process). Thereby, the efficiency of the process of injecting the working fluid 40 into the sealed space 36 and the process of evacuating the sealed space 36 can be achieved.

In addition, in 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 arranged in the radial direction of the inner pot 90 so as to face each other. Furthermore, as a cover for the deformation 1 of the tube 38, a pair of tube covers 110 covering only the tubes 38 are provided on the inner pot 90 instead of the cover 50. The tube cover 110 is formed in a substantially rectangular plate shape with the thickness direction in the up-down direction. In addition, the tube cover 110 is formed with a concave portion 110A that opens radially inward of the inner pot 90, and the concave portion 110A is formed into a circular shape when viewed from the radial direction of the inner pot. Furthermore, 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 covering the tube 38 can be used as a handle of the inner pot 90, and the tube 38 can be utilized as an attachment portion (core portion) of the handle (tube cover 110). Furthermore, 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 as the handle can be arranged in a well-balanced manner. Therefore, the ease of holding the inner pot 90 can be improved, and the convenience for the user can be improved.

In addition, in Modification 1, two tubes 38 are provided in the inner pot 90, but three or more tubes 38 may be provided in the inner pot 90. In this case, the working time of the tubes 38 (the working time of the working fluid 40 injection and the working time of the vacuum) may be considered to set the number of the tubes 38 provided in the inner pot 90. For example, when the working time for evacuation is longer than the injection time of the working fluid 40, the number of tubes 38 for evacuation may be greater than the number of tubes 38 for injection of the working fluid 40. As an example, the tube 38 for injecting the working fluid 40 may be one, and the tube 38 for evacuation may be two. As a result, it is possible to shorten the working time for using the tube 38 and further shorten the manufacturing time of the inner pot 90.

In addition, in the modification 1, the diameter sizes of the plurality of tubes 38 are set to be the same, but the diameter sizes of the plurality of tubes 38 may be set to different sizes. In this case, the diameter of the tube 38 provided in the inner pot 90 may be changed in consideration of the working time of the tube 38 as described above. For example, when the working time of vacuuming 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 injecting the working fluid 40. As a result, the working time can be shortened as described above.

In addition, in Modification 1, a plurality of (two) tubes 38 are arranged so as to be separated by 180 degrees 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, the plurality of tubes 38 may be arranged 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 tubes for working fluid injection and evacuation are connected to the tubes 38. In addition, for example, it is possible to suppress the dragging work of the tube connected to each tube 38 and the like, and to contribute to the reduction of the number of manufacturing hours of the inner pot 90.

(About deformation of tube 38 2)

In Modification 2, the structure is the same as Modification 1 except for the following points.

That is, as shown in FIG. 15, in Variation 2, the tube 38 is provided in the inner container 32. Specifically, the tube 38 protrudes (protrudes) radially inward of the inner pot 90 from the inner side wall portion 32B of the inner container 32. In addition, a communication hole that connects the inside of the tube 38 and the inside of the sealed space 36 is formed in the inner side wall portion 32B. Thereby, in the modification 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. In addition, since the tube 38 does not protrude radially outward of the inner pot 90, the inner pot 90 can be easily applied to a conventional rice cooker. Therefore, the versatility of the inner pot 90 can be improved. In addition, in modification 2, as in modification 1, a plurality of tubes 38 may be provided in the inner container 32.

In addition, in Variation 2, the vertical position of the tube 38 is set so that the tube 38 is positioned above the cooked rice (the rice of the maximum cooking amount of the inner pot 90). Therefore, even if the tube 38 is provided in the inner side wall portion 32B of the inner container 32, it is possible to suppress the contact between the cooked rice and the tube 38.

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

In addition, in the first to third embodiments, the height H of the bottom 36A of the enclosed space 36 is set to 4 mm, but from the viewpoint of increasing the capacity of the inner pot 30 without changing the size of the inner pot 30. When viewed, it is considered that the inner bottom wall portion 32A is lowered to further reduce the height dimension H. In addition, when the height dimension H is further reduced (for example, when it is made to be 3 mm or less), the volume ratio of the working fluid 40 of the closed space 36 to the bottom 36A is preferably set to 10 vol% to 80 vol%, particularly preferably Set to 30vol% ~ 80vol%.

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 set the working fluid 40 of the sealed space 36 relative to the bottom 36A The volume ratio is set to 5 vol% to 80 vol%, particularly preferably 8 vol% to 30 vol%.

In addition, in the inner pots 30, 60, 90, and 100 of the first embodiment (including modified examples) to the third embodiment, when the inner pots 30, 60, 90, and 100 are heated, the internal pressure of the enclosed space 36 Since it rises, a safety mechanism for preventing an abnormal increase in the internal pressure of the enclosed 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 FIGS. 16(A) and (B), a notch 32H constituting a safety mechanism is formed on the inner peripheral surface of the inner corner 32C of the inner container 32, and the notch 32H extends along The direction orthogonal to the circumferential direction is formed into a linear shape. The notch 32H is formed into a substantially V-shaped groove that opens radially inward of the inner container 32, and the portion of the inner container 32 where the notch 32H is formed is a thin portion 32I (broadly speaking, it is a "fragile portion") Elements to master). Therefore, in the inner container 32, the strength of the thin portion 32I is configured to be lower than the strength of other portions.

In addition, the shape (depth and width) of the notch 32H is set so that the thin portion 32I will break when the internal pressure of the enclosed space 36 is greater than a predetermined value. Thus, when the inner pot 90 is heated, when the internal pressure of the enclosed space 36 is greater than a predetermined value, the thin-walled portion 32I will break, and the vapor in the enclosed space 36 will pass from the broken portion to the lower portion of the inner pot 90 (details In other words, the part equipped with the meter) is sprayed. Therefore, the steam can escape from the steam tower of the lid 24 of the rice cooker 10 through the opening of the inner pot 90. Therefore, the abnormal increase in the internal pressure of the enclosed space 36 can be suppressed, and the safety of the rice cooker 10 can be improved.

In addition, in the example shown in FIGS. 16(A) and (B), the notch 32H extends linearly 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 so as to extend along the circumferential direction of the inner pot 90, or the notch 32H may be formed so as to extend obliquely with respect to the circumferential direction of the inner pot 90.

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

Furthermore, in the example shown in FIGS. 16(A) and (B), the cross-sectional shape of the notch 32H is formed into 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 semi-circular groove shape.

In addition, in the above-mentioned safety mechanism, the thin portion 32I is formed in the inner container 32, but the place where the thin portion 32I is formed can be arbitrarily set.

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

In addition, for example, the thin-walled portion 32I may be formed on the upper portion of the inner side wall portion 32B (preferably on the upper side of the rice of the maximum cooking volume of the inner pot 90). In this case, the thin-walled portion 32I is arranged at a position away from the bottom of the inner pot 90 (that is, the portion of the inner pot 90 that is heated). Thus, the deterioration of the thin portion 32I can be suppressed. In particular, by arranging the thin-walled portion 32I at a position above the rice of the maximum cooking amount of the inner pot 90, it is possible to suppress contact with the thin-walled portion 32I after cooking.

In addition, in the above 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 the inner container 32 . In addition, the thin portion 32I may be formed in the inner container 32 and the outer container 34. Furthermore, when the thin-walled portion 32I is formed in the inner container 32 and the outer-tank 34, for example, when the internal pressure of the enclosed space 36 rises abnormally, even when one thin-walled portion 32I is not broken, the other The thin portion 32I is broken, and the vapor escapes to the outside of the enclosed space 36. Thus, the safety of the rice cooker 10 can be further improved.

In addition, from the viewpoint of reducing the thickness of the inner container 32 to form the thin portion 32I or the like, a portion of the inner container 32 (inner side wall portion 32B) may be pressed when the inner container 32 is pressed. The flat portion 32I is formed. For example, although the illustration is omitted, a circular concave portion that is flattened inward in the plate thickness direction may be formed on the inner peripheral surface or outer peripheral surface of the inner side wall portion 32B, and the portion where the concave portion is formed may be thin部32I.

In addition, 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 the thin portion 32I. For example, although the illustration is omitted, a portion of the inner side wall portion 32B may be half-punched radially inward or radially outward, and the boundary portion of the half-punched portion may be the thin portion 32I.

Thus, the thin-walled portion 32I can be easily formed, and the inner pot 90 can be manufactured at a low cost. In addition, as described above, the concave portion or the half-punched 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-punched portion may be arbitrarily set.

In addition, from the viewpoint of allowing the vapor to escape to the outside of the enclosed space 36 when the internal pressure in the enclosed space 36 rises abnormally, a safety valve (as an example) may be provided in the inner container 32 or the outer container 34 , Spring safety valve) structure. In this case, when the internal pressure of the enclosed space 36 rises abnormally, the steam can escape to the outside of the enclosed space 36 without damaging the inner pot 90.

In addition, in the first embodiment, the inner pot 30 is provided with the connecting pin 42, and the inner bottom wall portion 32A and the outer bottom wall portion 34A are connected together by the connecting pin 42. Alternatively, as shown in FIG. 17, in the inner pot 30, the connecting pin 42 (center pin 44 and outer peripheral pin 46) may be omitted, and the inner bottom wall portion 32A and the outer bottom wall portion 34A may not be connected. .

In addition, although the illustration is omitted, in the inner pots 30, 60, 90, and 100 of the first embodiment (including modified examples) to the third embodiment, the inner side wall portion 32B of the inner container 32 and the outer container A connecting pin 42 is provided between the outer side wall portions 34B of 34, and the inner side wall portions 32B and the outer side wall portions 34B are connected by the connecting pins 42. In this case, the connecting pin 42 is arranged with the radial direction of the inner pots 30, 60, 90, 100 as the axial direction, and the inner side wall portion 32B and the outer side wall portion 34B are connected by the connecting 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, 100 can be suppressed.

Furthermore, 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 arranged at equal intervals. Thereby, the deformation of the inner side wall portion 32B and the outer side wall portion 34B during heating of the inner pots 30, 60, 90, 100 can be suppressed, and the space between the inner side wall portion 32B and the outer side wall portion 34B of the sealed space 36 can be realized Uniformity of the gap. As a result, in the circumferential direction of the inner pots 30, 60, 90, and 100, unevenness in the amount of steam 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 heated uniformly in the circumferential direction of the inner container 32.

In addition, in the first embodiment (including modification examples) 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 also be used. The structure of the cover 50 is omitted.

In addition, in the cover 50 of the first embodiment (including modification examples) to the third embodiment, portions covering the first flange 32D and the second flange 34D of the inner pots 30, 60, 90, 100 and the cover tube Both parts of 38 are formed into a ring shape. Alternatively, the cover 50 may be formed as an integral part of 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 (that is, the tube cover 110 described above) 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 unrecognizablely.

In addition, in the inner pot 30 (60) of the first embodiment (including modifications), the first flange 32D of the inner container 32 is wound around the second of the outer container 34 at the opening of the inner pot 30 (60 ). The flange 34D is folded back and forth to ensure the airtightness of the enclosed space 36, but the structure to ensure the airtightness of the enclosed space 36 is not limited to this.

For example, as shown in FIG. 18, the second flange 34D may be formed to be folded back 180 degrees radially inward of the inner pots 30, 60, and the first flange 32D of the inner container 32 is wound after being folded back Of the second flange 34D. That is, in this case, the second flange 34D assumes a superimposed structure in which the top and bottom overlap. Furthermore, the upper flange portion 32D1 and the lower flange portion 32D2 of the first flange 32D press-contact the second flange 34D that exhibits the overlapping structure up and down. Thereby, the rigidity of the opening of the inner pot 30 (60) can be improved while ensuring the airtightness of the sealed space 36.

In addition, in the first embodiment (including modification 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 (as an example, only the inner bottom wall portion 32A or only the inner side wall portion 32B) may be rough-processed, and the inner circumferential surface of the inner container 32 may be formed into a concave-convex shape . For example, the inner circumferential surface of the inner container 32 may be subjected to diamond coating treatment. In addition, for example, the inner peripheral surface of the inner container 32 may be subjected to sandblasting, and after sandblasting, Teflon processing may be performed. As a result, irregularities are formed on the inner circumferential surface of the inner container 32. Therefore, when cooking rice, relatively uneven bubbles are generated in the inner pot due to the unevenness. As a result, the generation of the bubbles can uniformly heat the rice in the inner pot.

In addition, in the first to third embodiments (including modified examples) to the third embodiment, in order to raise the vapor generated in the enclosed space 36 well, the outer surface of the inner container 32 and the inner surface of the outer container 34 are mirror-finished. Treatment, but from the viewpoint of easily generating steam in the enclosed space 36 during heating of the inner pot, rough processing may be performed on the outer surface of the inner container 32 and the inner surface of the outer container 34. 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 uneven surface of the inner side surface of the inner container 32 and the inner side surface of the outer container 34.

In addition, in the inner pots 30, 60, 90, and 100 of the first embodiment (including modifications) to the third embodiment, the plate thickness of the inner container 32 and the plate thickness of the outer container 34 are set to be the same, but the plate thickness of the outer container 34 may be the same. The plate thickness of the inner container 32 and the plate thickness of the outer container 34 are set to different plate thicknesses. For example, the plate thickness of the inner container 32 may be set to be thinner than the plate thickness of the outer container 34, so as to promote heating of the inner container 32. In addition, by setting the plate thickness of the inner container 32 to be thinner than the plate thickness of the outer container 34, the heat of the vapor of the working fluid 40 vaporized in the enclosed space 36 can be reduced in the inner pot 30, 60, 90, 100. The inner side wall portion 32B efficiently dissipates heat into the inner pots 30, 60, 90, and 100.

In addition, in the first embodiment (including 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 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 thinner than the plate 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.

In addition, in the first embodiment (including modified examples) to the third embodiment, the inner container 32 and the outer container 34 are composed of a magnetic body (stainless steel). Instead, the inner container 32 may be composed of a high thermal conductor such as copper or aluminum. In this case, also when the inner pots 30, 60, 90, 100 are heated, the inner container 32 can be efficiently heated.

Alternatively, the inner container 32 may be molded using a pre-coated steel plate pre-coated with a fluorine-based resin on the surface. Thereby, the manufacturing process of the inner pot 30, 60, 90, 100 can be shortened.

In addition, in the first embodiment (including modified examples) to the third embodiment, the inner pots 30, 60, 90, and 100 are applied to the IH type rice cooker 10, but the rice cookers using the inner pots 30, 60, 90, and 100 are not limited. Limited to this. For example, the heating part 16 of the rice cooker 10 may be changed to a heater, and the inner pot 30, 60, 90, 100 may be heated by the heater.

(Note)

As described above, the present invention has been described from the viewpoint of efficiently heating the inner side wall of the heating cooker in the heating cooker having a double-wall structure with an enclosed space inside, but from other viewpoints, it may be as follows Understand that way.

That is, in the heating cooker described in the background art, when the working fluid is injected into the enclosed space and the bottom of the heating cooker is heated, the working fluid will boil, and the vaporized gas from the working fluid follows the seal The side of the space rises. Thus, the inner side wall of the heating cooker is heated by steam. Furthermore, the vapor heated by the side wall condenses and turns into a liquid as a working fluid. The working fluid that has become a liquid drops by its own weight and returns to the bottom of the closed space. Moreover, in the working fluid, by repeating the above-mentioned phase change cycle, the side portion of the heating cooker is heated.

However, in the above-mentioned heating cooker, there is room for improvement in the aspects shown below. That is, in the above heating cooker, as described above, when the bottom of the heating cooker is heated, the vaporized from the working fluid rises along the side of the closed space. Furthermore, by continuously heating the heating cooker, the air pressure (pressure) in the enclosed space will increase. Therefore, the bottom of the enclosed space expands, and the bottom of the heating cooker may be deformed. Therefore, in a heating cooker having a sealed space inside, it is desired to have a structure capable of suppressing deformation of the heating cooker due to expansion.

The present invention has been made in consideration of the above facts, and its object is to provide a heating cooker capable of suppressing expansion during heating.

A first form for solving the above-mentioned problem is to provide a heating cooker which is formed in a bottomed cylindrical shape and presents a double-walled structure having an enclosed space inside, and includes a bottomed cylindrical inner container which constitutes the heating cooker The inner part of the bottom; a cylindrical outer container with a bottom, which constitutes the outer part of the heating cooker; a working fluid, which is injected into the enclosed space; a connecting portion, which is provided in the enclosed space, the inner container The inner bottom wall portion is connected to the outer bottom wall portion of the outer container.

The second aspect for solving the above-mentioned problem is the heating cooker of the first aspect, wherein the connecting portion is formed by a connecting pin extending in the axial direction of the heating cooker.

The third aspect for solving the above-mentioned problem is the heating cooker of the second aspect, in which the coupling pin is arranged at the center of the heating cooker in a plan view from the opening side of the heating cooker.

The fourth aspect for solving the above-mentioned problem is the heating cooker of the first aspect, in which the coupling portion extends radially from the center of the heating cooker when viewed from the opening side of the heating cooker.

The fifth aspect for solving the above-mentioned problem is the heating cooker according to the fourth aspect, and a communication hole for communicating the sealed space defined by the connecting portion is formed at the lower end portion of the connecting portion.

In summary, the technical methods disclosed in the present invention can effectively solve the problems of conventional knowledge, etc., and achieve the expected purpose and effect, and have not been published in the publication before the application, have not been publicly used, and have long-term progress. The invention mentioned in the Patent Law is correct, so I filed an application in accordance with the law, and sincerely prayed for the detailed examination and granted the invention patent to Zhi Dexin.

However, the above are only a few preferred embodiments of the present invention, which should not be used to limit the scope of the present invention, that is, any equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the description of the invention It should still fall within the scope of this invention patent.

〔this invention〕 10‧‧‧ rice cooker 12‧‧‧Rice cooker main body 14‧‧‧Inner pot storage 16‧‧‧Heating 18‧‧‧Power Department 20‧‧‧Temperature sensor 22‧‧‧Control Department 24‧‧‧ Cover 26‧‧‧Hinge mechanism 30‧‧‧Inner pot (heating cooker) 32‧‧‧Inner container 32A‧‧‧Inner bottom wall 32B‧‧‧Inner side wall 32C‧‧‧Inner corner 32D‧‧‧First flange 32D1‧‧‧Upper flange 32D2‧‧‧Lower flange 32G‧‧‧Deep drawing 32H‧‧‧Notch 32I‧‧‧Thin Wall Department 34‧‧‧Outside container 34A‧‧‧Outside bottom wall 34B‧‧‧Outside side wall 34C‧‧‧Outer corner 34D‧‧‧Second flange 34E‧‧‧Through hole 34F‧‧‧Link recess 34G‧‧‧Deep drawing 36‧‧‧Confined space 36A‧‧‧Bottom 36B‧‧‧Bottom 36C‧‧‧Side 38‧‧‧ tube 38A‧‧‧Riveting Department 40‧‧‧working fluid 42‧‧‧Link pin 44‧‧‧ Center pin 46‧‧‧Peripheral pin 50‧‧‧ cover 52‧‧‧Hood parts 52A‧‧‧Outer wall 52B‧‧‧Upper wall 52C‧‧‧lower wall 52D‧‧‧middle wall 52E‧‧‧First Storage Department 52F‧‧‧Second storage 52G‧‧‧buckle 52H‧‧‧Card clip 52J‧‧‧Snap hole 60‧‧‧Inner pot (heating cooker) 62‧‧‧Bottom plate 70‧‧‧Link board 70A‧‧‧Link 70B‧‧‧Connecting hole 72‧‧‧The first link board 74‧‧‧Second link board 80‧‧‧Middle board 90‧‧‧Inner pot (heating cooker) 92‧‧‧Sealing material 100‧‧‧Inner pot (heating cooker) 110‧‧‧tube cover 110A‧‧‧recess H‧‧‧The height dimension of the bottom of the enclosed space R‧‧‧Inner corner radius W‧‧‧Width of closed space

FIG. 1 is a longitudinal cross-sectional view of the inner pot of the first embodiment (an enlarged cross-sectional view taken along line 1-1 in FIG. 2 ). Fig. 2 is a plan view of the inner pot of the first embodiment viewed from above. Fig. 3 is an enlarged cross-sectional view showing an enlarged half of the inner pot shown in Fig. 1. Fig. 4 is a plan view of the cover shown in Fig. 1 after being partially cut away as seen from above. 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 rice when the inner pot shown in Fig. 1 is used for cooking rice. FIG. 7 is a graph showing the temperature data of the inner bottom wall portion and the outer side wall portion of the inner pot when the rice is cooked using the inner pot shown in FIG. When the volume ratio changes, the graphs are shown in different cases. Figure 7 (A) shows the case where the volume ratio of the working fluid is set to 3 vol%, Figure 7 (B) shows the case where the volume ratio of the working fluid is set to 10 vol%, and Figure 7 (C) shows the case where the working fluid is When the volume ratio is set to 85 vol%. FIG. 8 is an explanatory diagram for explaining the rise of vapor in the side portion of the enclosed space when the inner pot shown in FIG. 1 is heated. Fig. 9 is a longitudinal 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 a modification 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 diagram showing the inner bottom wall portion and the outer bottom wall portion. Linked perspective view of another variant. FIG. 11(A) is a longitudinal sectional view of the inner pot of the second embodiment (a sectional view taken on line 11A-11A of FIG. 11(B)), and FIG. 11(B) is shown in FIG. 11(A) Bottom view of the inner pot. Fig. 12 is an explanatory diagram for explaining the method of manufacturing the inner pot shown in Fig. 11. Fig. 13 is a longitudinal cross-sectional view of the inner pot of the third embodiment. FIG. 14(A) is a longitudinal cross-sectional view of the inner pot for explaining the modification 1 of the tube shown in FIG. 11 (cross-sectional view taken on line 14A-14A of FIG. 14(B)), and FIG. 14(B ) Is a bottom view of the inner pot shown in FIG. 14(A). Fig. 15 is a longitudinal cross-sectional view of an inner pot for explaining a modification 2 of the tube shown in Fig. 11. FIG. 16(A) is a longitudinal cross-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 of the notch shown in FIG. 16(A) ( (Enlarged cross-sectional view of line 16B-16B in Figure 16(A)). FIG. 16(C) is a partial longitudinal cross-sectional view of an example in which the notch of FIG. 16(A) is formed in the tube. FIG. 17 is a longitudinal cross-sectional view corresponding to FIG. 1 of another modification example 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.

30‧‧‧Inner pot (heating cooker)

32‧‧‧Inner container

32A‧‧‧Inner bottom wall

32B‧‧‧Inner side wall

32C‧‧‧Inner corner

32D‧‧‧First flange

32D1‧‧‧Upper flange

32D2‧‧‧Lower flange

34‧‧‧Outside container

34A‧‧‧Outside bottom wall

34B‧‧‧Outside side wall

34C‧‧‧Outer corner

34D‧‧‧Second flange

34E‧‧‧Through hole

36‧‧‧Confined space

36A‧‧‧Bottom

36B‧‧‧Bottom

36C‧‧‧Side

38‧‧‧ tube

38A‧‧‧Riveting Department

40‧‧‧working fluid

42‧‧‧Link pin

44‧‧‧ Center pin

46‧‧‧Peripheral pin

50‧‧‧ cover

52‧‧‧Hood parts

52A‧‧‧Outer wall

52B‧‧‧Upper wall

52C‧‧‧lower wall

52D‧‧‧middle wall

52E‧‧‧First Storage Department

52F‧‧‧Second storage

Claims (8)

A heating cooker is formed in a bottomed cylindrical shape and presents a double-wall structure with an enclosed space inside, characterized by comprising: a bottomed cylindrical inner container that constitutes the inner portion of the heating cooker; A bottom cylindrical outer container that constitutes the outer portion of the heating cooker; and a working fluid that is injected into the closed space in an amount that does not cover the entire bottom surface of the closed space, the heating cooker is provided There is a cover covering the overlapping portion, the overlapping portion is a first flange extending over the entire circumference of the opening of the inner container and a second protrusion extending over the entire circumference of the opening of the outer container The overlapping portion where the edges overlap in the vertical direction. The heating cooker according to item 1 of the scope of the patent application, wherein the volume ratio of the working liquid phase to the bottom of the closed space is set at 4 vol% to 80 vol%. The heating cooker according to item 1 or 2 of the patent application range, wherein the height dimension of the closed space at the bottom of the heating cooker is set to the side of the heating cooker when viewed in longitudinal section The closed space has a width or more and is set to 2 mm or more. The heating cooker as described in item 1 or 2 of the patent application range, wherein the enclosed space is maintained at a negative pressure or vacuum below 0.01 standard atmospheric pressure. The heating cooker according to item 4 of the patent application scope, wherein the inner side wall portion of the inner container or the outer side wall portion of the outer container is provided when the working fluid is injected into the enclosed space And a plurality of tubes used when the enclosed space is made into negative pressure or vacuum. The heating cooker as described in item 5 of the patent application scope, wherein, A plurality of tubes are arranged 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 item 1 or 2 of the patent application range, wherein an inner corner that is convex 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 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 configures the sealed space are mirror-finished.

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