JP3596503B2 - Electric water heater - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric water heater, particularly to a heating structure.
[0002]
[Prior art]
Conventionally, a heat generating structure of this type of electric water heater generally has a configuration as shown in FIGS. That is, reference numeral 1 denotes a container for storing the liquid, and a concave portion 1b is formed in the container bottom plate 1a forming the bottom of the container 1 when viewed from the outside of the bottom surface. A flat and ring-shaped heating element 2 for heating the liquid in the container 1 by energization is accommodated in the recess 1b. Reference numeral 3 denotes a heat diffusion plate formed of aluminum or the like which is in close contact with the heating element 2 below the heating element 2. Reference numeral 4 denotes an electric connection terminal connected to the heating element 2. The electric connection terminal 4 is insulated by an insulating member 5 formed of an insulating material such as pottery and connected to a power supply lead wire 10. Reference numeral 6 denotes a fixing plate for holding the heating element 2 sandwiched between the container bottom plate 1a and the container bottom plate 1a. The fixing plate 6 has a through hole 7 through which the insulating member 5 passes. If the insulating member 5 is pressed against the through hole 7 when the fixing plate 6 is attached to the container bottom plate 1a, the insulating member 5 may be damaged or the pressure contact dimension of the heating element 2 may be changed. It is a size that can afford. Reference numeral 8 denotes a detector such as a thermostat which is attached to the concave portion 1b and controls the temperature in the container 1. Reference numeral 9 denotes a thermal fuse which cuts off the power supply to the heating element 2 when abnormal heat is generated.
[0003]
Next, the operation of the conventional electric water heater will be described. Normally, when water is supplied into the container 1 and the power is supplied, the heating element 2 generates heat and warms the water in the container via the container bottom plate 1a, and the water temperature rises. Then, the detector 8 is warmed with the rise of the water temperature, and when the water temperature reaches a predetermined temperature, the power supply to the heating element 2 is stopped by the detector 8. If the power is further supplied after the water temperature reaches the predetermined temperature due to the failure of the detector 8, the temperature fuse 9 operates and the power supply to the heating element 2 is cut off. 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 melts, the heating element 2 is short-circuited, and the current is cut off.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, the through hole 7 for passing the insulating member 5 through the fixing plate 6 is provided with a sufficient size for the insulating member 5, so that the failure of the detector 8 and the thermal fuse 9 occurs. There is a problem that the molten heat diffusion plate 3 protrudes from the through hole 7 depending on the flow direction.
[0005]
The present invention has been made to solve such a conventional problem, and has as its object to cool a molten heat diffusion plate and prevent it from protruding from a through hole.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems, the present invention provides a heat sink, wherein the outer periphery of the insulator is covered with a metal radiator plate leaving a gap for allowing the insulator to pass through , and the radiator plate is connected to the through-hole. The molten heat diffusion plate is cooled and solidified inside 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 provides a container for storing a liquid, a container bottom plate forming a bottom surface of the container, a heating element for supplying heat to the container bottom plate, and diffusing heat in contact with the heating element. A heat diffusion plate, an electrical connection terminal connected to the heating element, an insulating member 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 is formed of a material having a lower melting point than the fixing plate, and the fixing plate is provided with a through hole for passing the insulating member, and the outer periphery of the insulating member is made of metal except for a gap enough to pass the insulating member. And the radiator plate is connected to the through hole . Then, the molten heat diffusion plate can be cooled by the heat radiating plate and can be prevented from protruding from the through hole.
[0008]
According to a second aspect of the present invention, in the configuration of the first aspect, the heat radiating plate is formed integrally with the fixing plate. Since the heat radiating plate is formed integrally with the fixing plate, it is not necessary to separately prepare and connect the components, and it is possible to prevent the inexpensive and easily melted heat diffusion plate from protruding.
[0009]
The invention according to claim 3 of the present invention is provided with a far side of the gap between the radiator plate and the insulating member from the heating element in the configuration of any one of claims 1 to 3 in parallel with the insulating member, the heat radiating plate The base side is inclined and wide open, and the base side is inclined and enlarged, so that the insulator easily passes between the through hole and the heat sink when assembling, and excessive force is applied to the electrical connection terminal. I can't call it.
[0010]
According to a fourth aspect of the present invention, in the configuration according to the first or second aspect, the insulating member has a stepped shape on the side of the heating element and is enlarged, and a part or all of the stepped portion is covered with a heat radiating plate. The path through which the air flows . By covering a part or the entirety of the stepped portion with the heat radiating plate, the flow path of the molten heat diffusion plate becomes longer, and the heat radiating area of the heat radiating plate is increased, whereby cooling becomes more effective.
[0011]
According to a fifth aspect of the present invention, in the configuration according to any one of the first to fourth aspects, the fixing plate is stepped outward with respect to a portion of the electric connection terminal connected to the heating element to expand. A space is provided between the heating element and the fixing plate. Then, the part covering the electrical connection terminals of the fixed plate is stepped outward to provide a space between the heating element and the fixed plate, so that the molten heat diffusion plate flows into the space where it easily flows and accumulates. And the cooling by the heat sink becomes easy.
[0012]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
(Example 1)
FIG. 1 is a cross-sectional view of a heat generating structure of the electric water heater of the present 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 concave portion 21b is formed in a container bottom plate 21a forming the bottom of the container 21 when viewed from outside the bottom. A flat ring-shaped heating element 22 for energizing and heating the liquid in the container 21 is accommodated in the recess 21b. Reference numeral 23 denotes a heat diffusion plate formed of aluminum and adhered to the lower side of the heating element 22. Reference numeral 24 denotes an electrical connection terminal connected to the heating element 22. The electrical connection terminal 24 is insulated by an insulating member 25 made of an insulating material such as ceramics and connected to a power supply lead wire 32. Reference numeral 26 denotes a fixing plate for holding the heating element 22 sandwiched between the container bottom plate 21a and the container bottom plate 21a. The fixing plate 26 has a through hole 27 through which the insulating member 25 passes. A metal heat radiating plate 28 is provided on the outer periphery of the insulating member 25 leaving a gap (about 0.5 mm or less in this embodiment) through which the insulating member 25 passes, and covers the insulating member 25. The heat sink 28 is connected and fixed to the through hole 27.
[0014]
Reference numeral 29 denotes a temperature detector such as a thermostat which is attached to the concave portion 21b and controls the temperature of the container 21, and reference numeral 30 denotes a temperature fuse of an overheating prevention device which cuts off the power supply to the heating element 22 when abnormal heat is generated. The detector 29 is not limited to the thermostat, and may be any device capable of detecting the temperature of the container bottom plate 21a. The overheat prevention device 30 is not limited to the temperature fuse, and may detect abnormal heat generation and cut off the power supply to the heating element 22. Just fine.
[0015]
Next, the operation of the heat generating structure of the electric water heater having the above configuration will be described. Normally, when water is supplied into the container 21 and energized, the heating element 22 generates heat and warms the water in the container via the container bottom plate 21a, and the water temperature rises. Then, the detector 29 is also heated as the water temperature rises, and when the water temperature reaches a predetermined temperature, the power supply to the heating element 22 is stopped by the detector 29.
[0016]
Further, when the power is further supplied even after the water temperature reaches the predetermined temperature due to the failure of the detector 29, the excessive temperature rise prevention device 30 operates to cut off the power supply to the heating element 22. Further, when a failure of the over-temperature rise prevention device 30 occurs, the heat diffusion plate 23 is heated by the heat of the heating element 22 and melts, the heating element 22 is short-circuited, and the current is cut off. At this time, the melted heat diffusion plate 23 tends to flow out of the gap if there is a gap in various directions. Although it tends to flow out from between the insulating member 25 and the heat radiating plate 28, since the heat radiating plate 28 is provided upright so as to cover the outer periphery of the insulating member 25, the melted heat diffusion plate 23 is formed at the heat radiating plate 28. It is cooled and does not flow out.
[0017]
(Example 2)
FIG. 4 is an enlarged sectional view of a main part of the heat generating structure of the present embodiment. Since the basic configuration is the same as that of the first embodiment, differences from the first embodiment will be described with reference to FIG. In the present embodiment, the heat radiating plate 28 is formed integrally with the fixing plate 26, and it is not necessary to separately prepare and connect the heat radiating plate 28 and the fixing plate 26, and similar effects can be expected at low cost and easily.
[0018]
(Example 3)
FIG. 5 is an enlarged sectional view of a main part of the heat generating structure of the present embodiment. Since the basic configuration is the same as that of the first embodiment, differences from the first embodiment will be described with reference to FIG. In this embodiment, the gap between the heat radiating plate 28 and the insulating member 25 is made larger by providing the side farther from the heating element 22 in parallel with the insulating member 25 and inclining the base side. It is easy to pass between the heat radiating plates 28, and no excessive force is applied to the electric connection terminals 24. Also at this time, the melted heat diffusion plate 23 is cooled and solidified at a portion of the heat radiation plate 28 parallel to the insulating member 25 and does not flow out.
[0019]
(Example 4)
FIG. 6 is an enlarged sectional view of a main part of the heat generating structure of the present embodiment. Since the basic configuration is the same as that of the first embodiment, differences from the first embodiment will be described with reference to FIG. In this embodiment, a stepped portion 25a is provided in which the insulating member 25 has a stepped shape and the heating element 22 side is enlarged. The stepped portion 25a is partially or entirely covered with a heat sink 28.
[0020]
In this configuration, the flow path of the melted heat diffusion plate 23 becomes longer, the heat radiation area of the heat dissipation plate 28 increases, and cooling becomes more effective, so that the melted heat diffusion plate 23 does not protrude.
[0021]
(Example 5)
7 and 8 are enlarged sectional views of a main part of the heat generating structure of the present embodiment. Since the basic configuration is the same as that of the first embodiment, points different from the first embodiment in FIGS. 7 and 8 will be described. In this embodiment, a portion of the fixed plate 26 covering the electrical connection terminals 24 is stepped outward to provide a stepped portion 33, and a space 31 is provided between the heating element 22 and the fixed plate 26.
[0022]
In this configuration, since the melted heat diffusion plate 23 flows and accumulates in the space 31 into which the melted heat diffusion plate 23 easily flows, the amount of the heat diffusion plate 23 which tends to protrude is reduced, and cooling by the heat radiation plate 28 is facilitated. Further, since the space 31 is provided by stepping the portion covering the electric connection terminal 24 outward, the melted heat diffusion plate 23 tends to accumulate in the space 31, and as a result, flows toward the electric connection terminal 24 and short-circuits. There is also an effect of cutting off the current.
[0023]
【The invention's effect】
As described above, according to the heat generating structure of the electric water heater of the present invention, the outer periphery of the insulating member is covered with a metal heat radiating plate leaving a gap enough to pass the insulating member , and the heat radiating plate is connected to the through hole. Thus, the heat diffusion plate melted by the heat radiating plate can be cooled and solidified to prevent the heat diffusion plate from protruding from the through hole.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a heat generating structure of an electric water heater showing a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a main part of the heat generating structure. FIG. 4 is an enlarged cross-sectional view of a main part of a heat generating structure of an electric water heater according to a second embodiment of the present invention. FIG. 5 is an enlarged cross-sectional view of a main part of a heat generating structure of an electric water heater according to a third embodiment of the present invention. 6 is an enlarged sectional view of a main part of a heat generating structure of an electric water heater according to a fourth embodiment of the present invention. FIG. 7 is an enlarged cross-sectional view of a main part of a heat generating structure of an electric water heater according to a fifth embodiment of the present invention. 8 is a bottom perspective view of the heating structure. 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 a main part of the heating structure. Bottom perspective view of heat generating structure [Explanation of symbols]
21 Container 21a Container bottom plate 22 Heating element 23 Heat diffusion plate 24 Electric connection terminal 25 Insulator 25a Stepped portion 26 Fixed plate 27 Through hole 28 Heat sink 31 Space

Claims (5)

A container that stores the 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 contacts and diffuses heat with the heating element, and is connected to the heating element. Electrical connection terminal, an insulating member 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, wherein the heat diffusion plate has a lower melting point than the fixing plate. formed of a material, the the fixed plate provided with a through hole through which the insulating member, the outer periphery of the insulating member is covered with a heat radiating plate made of metal, leaving a gap of only passing the insulating member, wherein said heat radiating plate Electric water heater connected to the through hole . 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 , wherein a gap between the heat radiating plate and the insulating member is provided on a side farther from the heating element in parallel with the insulating member, and a base side of the heat radiating plate is inclined and widely opened. The electric water heater according to claim 1 or 2, wherein the heating element 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 to lengthen a flow path of the heat diffusion plate . 3. The electric water heater according to claim 1 , wherein the fixing plate is stepped outward to expand the portion of the electric connection terminal connected to the heating element, and a space is provided between the heating element and the fixing plate.

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