JP2003093233A - Electric kettle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent protruding and falling off of a thermal diffusion plate melted by an overheated heating element through the through-hole of the insulation fixture and the fixed board in case of the breakdown of the detector of the heating element and the over-temperature preventer of an electric kettle. SOLUTION: A thermal diffusion plate 23 composed of an aluminium wedged between the bottom surface of a heating element 22 and a fixed board 26 is melted by an overheated heating element and the molten part of the thermal diffusion plate 23 tends to outflow through the through-hole 27 of the fixed board 26. This outflow is prevented by providing a slight gap to the periphery of the insulation fixture 25 and covering it by a metal heat-sink 28, connecting the heat-sink 28 to the through-hole 27, and solidifying the outflow of the thermal diffusion plate by cooling it with the heat-sink 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater, and more particularly to a heating structure.

[0002]

2. Description of the Related Art Conventionally, a heat generating structure of an electric water heater of this type has generally been constructed as shown in FIGS. That is, 1 is a container for storing a liquid, and a container bottom plate 1a forming the bottom of the container 1 has a recess 1b when viewed from the outside of the bottom surface.
Are formed. A flat ring-shaped heating element 2 for heating the liquid in the container 1 by energization is housed in the recess 1b. Reference numeral 3 is a heat diffusion plate formed of aluminum or the like on the lower side of the heating element 2 and in close contact with the heating element 2. Reference numeral 4 is an electrical connection terminal connected to the heating element 2, and the electrical connection terminal 4 is insulated by an insulator 5 made of an insulating material such as earthenware and connected to a lead wire 10 for a power source. Reference numeral 6 denotes a fixing plate for sandwiching the heating element 2 sandwiched between the container bottom plate 1a and the container bottom plate 1a, and the fixing plate 6 is provided with a through hole 7 through which the insulator 5 is inserted. When the fixing plate 6 is attached to the container bottom plate 1a, if the insulating tool 5 is pressed into contact with the through hole 7, the insulating tool 5 may be damaged or the pressure contact size of the heating element 2 may change. However, the size is large. Also, 8
Is a detector such as a thermostat attached to the recess 1b for controlling the temperature inside the container 1, and 9 is a heating element 2 when abnormal heat is generated.
It is a thermal fuse that cuts off the power supply to.

Next, the operation of the electric water heater in the conventional example will be described. Normally, when water is put in the container 1 and electricity is applied, the heating element 2 generates heat to heat the water in the container via the container bottom plate 1a, and the water temperature rises. Then, as the water temperature rises, the detector 8 is also warmed, and when the water temperature reaches a predetermined temperature, the detector 8 stops energizing the heating element 2. When the detector 8 fails and the water temperature reaches a predetermined temperature and the power is further energized, the thermal fuse 9 operates and the heating element 2
To turn off the power. Further, when a failure of the thermal fuse 9 occurs, the heat diffusion plate 3 is heated by the heat of the heating element 2 and melted, and the heating element 2 is short-circuited and the current is cut off.

[0004]

However, in the above-mentioned conventional structure, the fixing plate 6 is provided with the through hole 7 through which the insulating tool 5 is inserted, with a sufficient dimension for the insulating tool 5, so that the detector 8 and the temperature There is a problem that when the fuse 9 fails, the melted heat diffusion plate 3 protrudes from the through hole 7 depending on the flow direction.

The present invention is intended to solve such a conventional problem, and it is an object of the present invention to cool a molten heat diffusion plate and prevent it from protruding from a through hole.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a gap between the outer circumference of an insulating tool and a metallic heat sink to cover the heat sink and connect the heat sink to the through hole. Thus, the heat diffusion plate melted inside the heat dissipation plate is cooled and solidified to prevent the heat diffusion plate from protruding from the through hole.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is
A container that stores a liquid, a container bottom plate that forms a bottom surface of the container, a heating element that supplies heat to the container bottom plate, a heat diffusion plate that is in contact with the heating element and diffuses heat, and is connected to the heating element. And a fixing plate for sandwiching the heating element and the heat diffusion plate with the outside of the container bottom plate, the heat diffusion plate having a lower melting point than the fixing plate. The fixing plate is provided with a through hole through which the insulating tool is passed, a gap is provided between the through hole and the outer periphery of the insulating tool, and the heat dissipation plate is connected to the through hole while maintaining the gap. It was done. Then, the heat radiating plate can cool the melted heat diffusion plate and prevent it from protruding from the through hole.

The invention according to claim 2 of the present invention is the invention according to claim 1.
In the structure described, the heat dissipation plate is formed integrally with the fixed plate. Since the heat dissipation plate is formed integrally with the fixed plate, it is not necessary to separately prepare and connect the components, and it is possible to prevent the heat diffusion plate that is inexpensive and easily melted from protruding.

The invention according to claim 3 of the present invention is the invention according to claim 1.
In the structure according to any one of 1 to 3, the insulating member is formed by enlarging the heating element side in a stepped shape and enlarging a part or all of the stepped portion with a heat sink, and inclining the root side. By increasing the size, the insulating tool can easily pass between the through hole and the heat dissipation plate during assembly, and an unreasonable force is not applied to the electrical connection terminal.

The invention according to claim 4 of the present invention is the invention according to claim 1.
Alternatively, in the configuration described in 2, the insulator has a stepped shape on the heating element side and is enlarged, and a part or all of the stepped portion is covered with a heat dissipation plate. By covering a part or all of the stepped portion with the heat radiating plate, the flow path of the melted heat diffusion plate becomes longer, and the heat radiating area of the heat radiating plate increases, so that cooling becomes more effective.

The invention according to claim 5 of the present invention is the invention according to claim 1.
In the structure described in any one of 1 to 4, the portion of the fixed plate that covers the electrical connection terminals is pushed outward to provide a space between the heating element and the fixed plate. And by pushing the part covering the electrical connection terminal of the fixed plate to the outside to provide a space between the heating element and the fixed plate, the molten heat diffusion plate flows and accumulates in a space that easily flows in, so it seems to stick out The amount of heat radiation is reduced, and cooling by the heat sink becomes easier.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a heat generating structure of an electric water heater according to this embodiment, FIG. 2 is an enlarged view of a main part, and FIG. 3 is a bottom perspective view of the heat generating structure. 1 to 3,
Reference numeral 21 denotes a container for storing a liquid, and a container bottom plate 21a forming the bottom of the container 21 has a recess 21b when viewed from the outside of the bottom. A flat, ring-shaped heating element 22 for energizing and heating the liquid in the container 21 is housed in the recess 21b. Reference numeral 23 is a heat diffusion plate made of aluminum that is in close contact with the lower side of the heating element 22. 24 is a heating element 2
The electrical connection terminal 24 is connected to the power supply lead wire 32, which is insulated by an insulator 25 made of an insulating material such as earthenware. 26 is a container bottom plate 21a
It is a fixed plate for sandwiching the heating element 22 sandwiched between and by the container bottom plate 21a, and the fixed plate 26 is provided with a through hole 27 through which the insulator 25 is inserted. On the outer periphery of the insulating tool 25, a metal radiator plate 28 is provided with a gap (about 0.5 in this embodiment) through which the insulating tool 25 passes.
(mm or less) is provided and covers the insulating member 25. The heat dissipation plate 28 is fixedly connected to the through hole 27.

29 is attached to the recess 21b and is attached to the container 21.
Temperature detectors such as thermostats to control the temperature of 3
Reference numeral 0 denotes a temperature fuse of the overheat prevention device that cuts off the power supply to the heating element 22 when abnormal heat is generated. The detector 29 is not limited to a thermostat and may be any one that can detect the temperature of the container bottom plate 21a, and the overheat prevention device 30 is not limited to a temperature fuse and may detect abnormal heat generation and cut off the power supply to the heating element 22. Good.

Next, the operation of the heating structure of the electric water heater having the above construction will be described. Normally, when water is put in the container 21 and electricity is applied, the heating element 22 generates heat and the container bottom plate 21a
The water in the container is warmed through and the water temperature rises. Then, when the detector 29 is also warmed as the water temperature rises and the water temperature reaches a predetermined temperature, the detector 29 stops energizing the heating element 22.

If the detector 29 fails and the water temperature is further energized even after reaching a predetermined temperature, the overheat prevention device 30 operates to cut off the energization to the heating element 22. Further, when a failure of the overheat prevention device 30 occurs, the heat diffusion plate 23 is heated by the heat of the heating element 22 and melted, and the heating element 22 is short-circuited and the current is cut off. At this time, the melted heat diffusion plate 23 tries to flow out from the flow gaps if there are flow gaps in various directions. Although it tries to flow out from between the insulator 25 and the heat sink 28, the heat sink 28 is provided upright so as to cover the outer periphery of the insulator 25, so that the melted heat diffusion plate 23 is located at the heat sink 28. It cools and does not solidify and flow out.

(Embodiment 2) FIG. 4 is an enlarged cross-sectional view of an essential part of a heat generating structure of this embodiment. Since the basic configuration is the same as that of the first embodiment, the points different from the first embodiment in FIG. 4 will be described. In this embodiment, the heat dissipation plate 28 is replaced by the fixed plate 26.
Since it is not necessary to separately prepare and connect the heat dissipation plate 28 and the fixing plate 26, the same effect can be expected at low cost and easily.

(Embodiment 3) FIG. 5 is an enlarged cross-sectional view of an essential part of a heat generating structure of this embodiment. Since the basic configuration is the same as that of the first embodiment, the points different from the first embodiment in FIG. 5 will be described. In this embodiment, the heat dissipation plate 28 and the insulator 2
The gap 5 is provided in parallel with the insulating member 25 on the side far from the heating element 22, and the base side is inclined to be large, so that the insulating member 25 can easily pass between the through hole 27 and the heat dissipation plate 28 during assembly. There is no need to force 24. Also at this time, the melted heat diffusion plate 23 is cooled and solidified in the portion of the heat dissipation plate 28 parallel to the insulator 25 and does not flow out.

(Embodiment 4) FIG. 6 is an enlarged cross-sectional view of a main part of the heat generating structure of this embodiment. Since the basic configuration is the same as that of the first embodiment, the points different from the first embodiment in FIG. 6 will be described. In this embodiment, a stepped portion 25a is provided in which the insulator 25 has a stepped shape and the heating element 22 side is enlarged. The stepped portion 25 a is partially or entirely covered with the heat dissipation plate 28.

In this structure, the flow path of the melted heat diffusion plate 23 becomes long, the heat dissipation area of the heat dissipation plate 28 increases, cooling becomes more effective, and the melted heat diffusion plate 23 does not stick out.

(Embodiment 5) FIGS. 7 and 8 are enlarged cross-sectional views of the essential parts of the heat generating structure of this embodiment. Since the basic configuration is the same as that of the first embodiment, the points different from the first embodiment in FIGS. 7 and 8 will be described. In this embodiment, the fixed plate 2
A portion of 6 which covers the electrical connection terminal 24 is pushed outward to provide a step pushing portion 33, and a space 31 is provided between the heating element 22 and the fixing plate 26.

In this structure, the melted heat diffusion plate 23 flows and accumulates in the space 31 where it easily flows, so that the amount of protrusion is reduced, and the cooling by the heat dissipation plate 28 is facilitated. Further, since the space 31 is provided by pushing the portion covering the electrical connection terminal 24 outward, the molten heat diffusion plate 23 is formed.
Tend to collect in the space 31, resulting in electrical connection terminals 24
It also has the effect of flowing to the side and breaking the short circuit to cut off energization.

[0023]

As described above, according to the heat generating structure of the electric water heater of the present invention, a gap is provided on the outer periphery of the insulating tool, and a metal heat radiating plate is further provided to cover the heat radiating plate with the through hole. By doing so, the heat diffusion plate melted by the heat dissipation plate can be cooled and solidified to prevent the heat diffusion plate from protruding from the through hole.

[Brief description of drawings]

FIG. 1 is a sectional view of a heating structure of an electric water heater showing a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the heat generating structure.

FIG. 3 is a bottom perspective view of the heat generating structure.

FIG. 4 is an enlarged sectional view of an essential part of a heating structure of an electric water heater showing a second embodiment of the present invention.

FIG. 5 is an enlarged sectional view of an essential part of a heating structure of an electric water heater showing a third embodiment of the present invention.

FIG. 6 is an enlarged sectional view of an essential part of a heat generating structure of an electric water heater showing a fourth embodiment of the present invention.

FIG. 7 is an enlarged sectional view of an essential part of a heat generating structure of an electric water heater showing a fifth embodiment of the present invention.

FIG. 8 is a bottom perspective view of the heating structure of FIG.

FIG. 9 is a cross-sectional view of a heating structure of an electric water heater showing a conventional example.

FIG. 10 is an enlarged cross-sectional view of an essential part of the heat generating structure.

FIG. 11 is a bottom perspective view of the same heating structure.

[Explanation of symbols]

21 containers 21a Container bottom plate 22 heating element 23 Heat diffusion plate 24 electrical connection terminals 25 insulation 25a Stepped portion 26 Fixed plate 27 through holes 28 Heat sink 31 space

Continued front page    (72) Inventor Hideaki Kobayashi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 3K092 PP13 QA05 QC02 QC21 QC43                       RF03 SS12 SS14 TT02 UA01                       UA17 UC08 VV06 VV28 VV29                 4B055 AA34 BA02 BA13 CA71 CC12                       CC13 CC45 DA02 DB02 FA20                       FB02 FC20 FD10

Claims (5)

[Claims] 1. A container for storing a liquid, a container bottom plate that forms a bottom surface of the container, a heating element that supplies heat to the container bottom plate, and a heat diffusion plate that is in contact with the heating element to diffuse heat. An electrical connection terminal connected to the heating element, an insulator for insulating the connection terminal, and a fixing plate for sandwiching the heating element and the heat diffusion plate with the outside of the container bottom plate, the heat diffusion plate being fixed The fixing plate is formed of a material having a melting point lower than that of the plate, the fixing plate is provided with a through hole for passing the insulating tool, a gap is provided between the through hole and the outer periphery of the insulating tool, and the heat dissipation plate is provided in the through hole. An electric water heater connected with a gap. 2. The electric water heater according to claim 1, wherein the heat radiating plate is formed integrally with the fixing plate. 3. The electric water heater according to claim 1 or 2, wherein a side of the heat dissipation plate far from the heating element is provided in parallel with the insulator, and the base side is inclined to be wide open. 4. The electric water heater according to claim 1, wherein the insulator has a stepped shape on the heating element side and is enlarged, and a part or all of the stepped portion is covered with a heat radiating plate. 5. The electric water heater according to any one of claims 1 to 4, wherein a portion of the fixed plate covering the electric connection terminal is pushed outward to provide a space between the heating element and the fixed plate.