JPS6149792B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat generating device used, for example, in a heater unit of a water heater.

Recently, highly safe positive temperature coefficient thermistors have been used as heat sources in various heat generating devices. However, there is a limit to the amount of heat generated by a single thermistor, so in order to obtain a large amount of heat, it is necessary to use multiple thermistors in combination, which makes the overall structure of the device complicated and difficult to assemble. There were drawbacks such as: Therefore, for products such as water heaters that require a high-output heat source, a device that uses a positive temperature coefficient thermistor as a heat source has not yet been put into practical use.

This invention was made based on the above circumstances, and its purpose is to provide a heat generating device that uses a highly safe positive temperature coefficient thermistor as a heat generating source, has a simple structure and is easy to assemble, and can provide a large output. This is what I am trying to do.

A case in which an embodiment of the present invention is applied to a heater unit for a water heater will be described below with reference to FIGS. 1 to 3.

In the figure, reference numeral 1 denotes a heating case made of stainless steel, for example. This heating case 1 has a watertight rectangular tube shape with an open end, and a flange portion 2 is formed around the opening 1a. An end plate 3 for closing the opening 1a is attached to the flange portion 2, and an end plate 3 for closing the opening 1a is attached to the flange portion 2.
is attached to the water storage tank wall surface 4, so that the heating case 1 protrudes into the water storage tank. 5, 5 are a pair of heating element blocks housed in the heating case 1 facing each other;
An elastic pressing member 6 in the form of a leaf spring is housed between the heating element blocks 5, 5 facing backwards, and this elastic pressing member 6 pushes the heating element blocks 5, 5
is pressed against the inner wall surface of the heating case 1.
A plurality of pairs of heating element blocks 5, 5 are accommodated in the heating case 1 along its longitudinal direction.

Next, the structure of each heating element block 5 will be explained based on FIG. 2. In the figure, reference numeral 10 denotes a molded holder made of a thermally insulating material, and a heating element accommodating recess 11 is formed in one side plane of this thermal insulating holder 10, and a fixing hole is formed in this heating element accommodating recess 11. 12, 12 are formed. Also, 13,
Reference numeral 13 designates a terminal fitting, and its central portion is provided with a bend-molded locking stepped portion 13a, which is press-fitted into the locking hole 12, and both bent ends of the terminal fitting 13 are inserted into the locking hole 12. By fitting the terminal fittings 13b, 13b into the recesses 14, 14 provided on both sides of the holder 10, the terminal fittings 13, 13 fit into the holder 1.
It is tied to 0. Moreover, the step part 13 for engagement
Holding parts 13c that can be expanded while being elastically deformed are formed on both sides of a, and the terminal parts 21, 21 of the heating element 20 are press-fitted into the holding parts 13c, 13c, respectively, so that the heating element 20 is held.

A positive temperature coefficient thermistor 22 as a heat generation source is housed inside the heating element 20. As shown in FIG. 3, this positive temperature coefficient thermistor 22 has electrodes 23, 23 bonded to its one side surface, and generates heat mainly on that surface, and its heating surface is made of an electrically insulating thin film such as silicone rubber. Heat conduction surface 24
covered by. Further, terminal portions 21, 21 that are electrically connected to the electrodes 23, 23 protrude from the other surface of the PTC thermistor 22, and these terminal portions 21, 21 are connected to the holding portions 13c, 13c of the terminal fittings 13, 13. It is press-fitted into the Therefore, when the heating element block 5 is assembled in the heating case 1 as shown in FIG. 1, the heating surface of the positive temperature coefficient thermistor 22 is as follows.
Due to the elastic force of the elastic pressing member 6, the heat conductive surface 24
It is brought into pressure contact with the inner wall surface of the heating case 1 via. An oil film of silicone grease is interposed between the heat conduction surface 24 and the inner wall surface of the heating case 1, so that the heat generated by the positive temperature coefficient thermistor 22 is efficiently transmitted to the heating case 1 side. .

Further, as shown in FIG. 1, on the back side of the holder 10, a recess 27 and a projection 28 are provided at positions spaced apart from each other, and these recesses 27 and projection 28 are connected to the other holder facing backward. 10 recesses 27
and a convex portion 28, thereby preventing relative displacement of the holders 10, 10 facing each other. Further, as shown in FIG. 1, the terminal fittings 13 adjacent to each other in the longitudinal direction of the heating case 1 are connected in series by lead wires 29. , 29 are connected to input terminals 30, 30 attached to this end plate 3.

In order to incorporate the heating element blocks 5 with such a configuration into the heating case 1, the heating element blocks 5 are assembled and interconnected, silicone grease is applied inside the heating case 1, and then the heating case is assembled. The heating element blocks 5 may be sequentially inserted through the openings 1a of 1. Each heating element block 5 is pressed against the inner wall surface of the heating case 1 by the elastic force of the elastic pressing member 6. The body blocks 5 are crimped and fixed at predetermined positions within the heating case 1.

The above-mentioned heat generating device assembled in this way can be operated by applying a voltage between the input terminals 30, 30, to the positive temperature coefficient thermistor 22 in the heat generating element 20...
generates a fever. More specifically, each PTC thermistor 22 mainly generates heat on one surface side to which the electrodes 23, 23 are bonded. This heat is then transferred to the heating case 1 side via the heat conduction surface 24 covering the surface of the PTC thermistor 22, thereby heating the water in the water storage tank.

According to the apparatus of the above embodiment, the heating element blocks 5 are crimped and fixed to the inner wall surface of the heating case 1 by the elastic force of the elastic pressing member 6, so that the assembly work of the heating element blocks 5 is easy. This can be done by simply inserting the . Furthermore, due to the elastic force of these elastic pressing members 6, the heat conductive surfaces 24 of the heating elements 20 are pressed against the inner wall surface of the heating case 1, and the heat conductive surfaces 24 and the inner wall surface of the heating case 1 are heated. Since they are in close contact with each other via silicone grease, which is a good conductor, the thermal resistance between them can be significantly reduced. In other words, the heat generating surface of the PTC thermistor 22 can be brought into close contact with the inner wall surface of the heating case 1 via the heat conductive surface 24 covering the heat generating surface, so that the heat generated by the PTC thermistor 22 can be efficiently transferred to the heating case 1. 1 side. Furthermore, due to the presence of the silicone grease, there is less friction when inserting the heating element blocks 5 into the heating case 1, and the insertion can be effected smoothly. Further, according to the above embodiment, the terminal parts 21, 21 of the heating element 20 are connected to the terminal fittings 13, 1.
Since the heating element 20 can be held in the holder 10 by simply press-fitting it into the holding parts 13c, 13c provided in the heating element block 3, the heating element block 5 can be assembled very easily. Moreover, the heating element blocks 5, 5 facing each other are fitted with the concave portion 27 and the convex portion 28 provided on the back surface of each holder 10, so that the heating element blocks 5, 5, etc. can be inserted easily. Since mutual displacement is prevented, the heating element blocks 5 can be smoothly inserted into the heating case 1 while maintaining correct postures. Moreover, according to the above embodiment, a large output heat generating device can be easily obtained by simply adding an arbitrary number of heat generating blocks 5.

FIG. 4 shows a first modification of the wiring structure in the above embodiment, in which the structure is simplified by using sockets 32 and lead wires 33 connected thereto instead of the terminal fittings 13, 13. The terminal portions 21, 21, . . . are electrically connected to each other.

FIG. 5 shows a second modification of the above embodiment, in which a fitting terminal piece 35 that can be expanded with elastic deformation is provided protruding from one end of each terminal fitting 13, and a fitting terminal piece 35 that can be expanded with elastic deformation is provided at the other end. An insertion terminal piece 36 is provided in a protruding manner to be removably connected to the fitting terminal piece 35 of the adjacent terminal fitting 13. In other words, by configuring the terminal fitting 13 in this manner, the electrical and mechanical connection of the heat generating blocks 5 is extremely facilitated, and any number of heat generating blocks 5 can be easily connected.

Furthermore, FIG. 6 shows another modification, in which a through hole 38 is provided in one side of the holder 10, and this through hole 38 is provided in one side of the holder 10.
A switching lead wire 39 is electrically connected within the switch 8. That is, this is carried out when a plurality of heating element blocks are connected in parallel to switch the strength of the heat generating capacity.The switching lead wire 39 can energize only some of the heating element blocks 5; The wire 39 is passed through the through hole 38 of the holder 10, which is disposed midway through the wiring until it reaches the target heating element block 5. Note that the switching lead wire 39 is connected to the through hole 3.
Instead of conducting through the inside of the holder 10, the holder 10 may be led out along sloped portions 10a provided on both sides of the holder 10, as shown in FIG.

In the above embodiments and modifications, the PTC thermistor 22 is housed inside the heating element 20, but the present invention is not limited to this, and the PTC thermistor 22 is directly housed in the holder 1.
Of course, the structure may be such that it is attached to zero. Further, the elastic pressing member 6 is not limited to a plate spring-like member as in the above embodiment, but may be any member that can press the heating element blocks 5, 5 against the inner wall surface of the heating case 1. Further, these elastic pressing members 6 may be integrally molded with the holder 10.

As detailed above, according to the present invention, a pair of heating element blocks each having a positive temperature coefficient thermistor attached to a holder that generates heat mainly on one surface are housed in a heating case via an elastic pressing member, Since the heating element block is crimped and fixed in the heating case by this elastic pressing member, each heating element block can be easily assembled into the heating case, and these heating element blocks can be added. You can easily obtain a high-output heat generating device by just going through the steps. Moreover, because the above-mentioned elastic pressing member allows the heat generating surface of the PTC thermistor to be brought into close contact with the inner wall surface of the heating case, the thermal resistance between the PTC thermistor and the heating case is reduced, and the generated heat is reduced. This has great effects, such as efficient transmission of heat to the heating case side.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, FIG. 1 is a sectional view showing the entire heating device, FIG. 2 is an exploded perspective view of the heating element block, and FIG. 3 is a perspective view of a positive temperature coefficient thermistor. FIGS. 4 to 7 each show a modification of the present invention. DESCRIPTION OF SYMBOLS 1... Heating case, 5... Heating element block, 6... Elastic pressing member, 10... Heat insulation holder, 13... Terminal fitting, 13c... Holding part, 21... Terminal part, 22... Positive temperature coefficient thermistor, 27... Recessed part, 28 ...Protrusion.

Claims (1)

[Claims] 1. A heating case and at least a pair of positive temperature coefficient thermistors that generate heat mainly on one surface are attached to a thermally insulating holder and housed in the heating case facing each other. A heat generating device characterized by comprising a heat generating block and an elastic pressing member provided between the heat generating blocks facing away from each other to press the heat generating surface of the PTC thermistor against the inner wall surface of the heating case. 2. The heat generating device according to claim 1, characterized in that silicone grease is provided between the heat generating surface of the positive temperature coefficient thermistor and the inner wall surface of the heating case. 3. The heat generating device according to claim 1, characterized in that a convex portion provided on one of the facing surfaces of the holder facing back and a recessed portion provided on the other facing surface are fitted into each other. 4. A holding part that expands by elastic deformation is formed on the terminal fitting provided on the holder, and the terminal part of the PTC thermistor is press-fitted into this holding part, so that the PTC thermistor is held in the holder. The heat generating device according to claim 1, wherein the heating device is small.