JPH0244115B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a heater used for heating water in a steam generation unit of a boiler-type inhaler, and in particular to a heater using a heating element made of a positive temperature coefficient thermistor (PTC). It is related to heaters.

[Background technology] A heater that uses a positive temperature coefficient thermistor as a heating element is
It consists of this positive temperature coefficient thermistor and a pair of electrode plates, and is used by being attached to a heat sink.
Conventionally, when attaching to this heat sink, the first step was to increase the heat dissipation area of the heat sink and to increase the contact area between the heating element and the heat sink.
As shown in the figure, a recess 6 is formed in a heat dissipation plate 5, and a heat generating element 1 sandwiched between a pair of electrode plates 2 is housed in this recess 6, which serves as a protrusion protruding from the front side. . This configuration is published in Japanese Patent Publication No. 52-138261.
The heating element 1 and the pair of electrode plates 2 are further sandwiched between a pair of insulating plates 4 which are good thermal conductors, and these are press-fitted into the recess 6 of the heat sink 5. Therefore, the heating element 1 and the electrode plate 2
is fixed to the heat sink 5. However, in this case, the heating element 1, the electrode plate 2, and the insulating plate 4 are all flat and are press-fitted into the recess 6, so that the electrode plate 2 and the heating element 1. Contact between the electrode plate 2 and the insulating plate 4 as well as between the insulating plate 4 and the inner wall of the recess 6 is not sufficient, so that heat is not efficiently generated to the heating element 1 and heat is not well transmitted to the heat sink 5. In addition, the position of each member may be shifted due to a falling impact or the like.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to ensure the contact between the electrode plate and the heat generating element, and to improve the transmission from the heat generating element to the heat sink. An object of the present invention is to provide a heater that can generate heat efficiently.

[Disclosure of the Invention] The heater according to the present invention is a heater in which a heating element made of a positive temperature coefficient thermistor and a pair of electrode plates are housed in a recess formed in a heat sink, and includes:
It is characterized in that at least one electrode plate is formed in a wedge shape, and the wedge-shaped electrode plate applies contact pressure for fixing and electrical contact of the heating element and itself to the heat sink. This occurs when the device is inserted into the recess.

Next, the present invention will be described in detail based on the illustrated embodiments shown in FIG. 2 and below. The heating element 1 is composed of a disk-shaped positive temperature coefficient thermistor made of ceramic, and a voltage is applied when a pair of electrode plates 2 are brought into contact with both surfaces. Both the heating element 1 and the pair of electrode plates 2 are attached to the heat sink 5 while being held by the holding frame 3. The heat dissipation plate 5 is formed as a die-cast product of zinc or aluminum, and has two parallel groove-shaped recesses 6 formed on the bottom surface, so that the surface serving as the heat dissipation surface has two grooves.
It has ridges of stripes. Further, the recess 6 has a tapered groove shape in which the groove width becomes narrower as the depth increases. In other words, it is possible to take the draft angle of the mold during molding, making it easier to release the mold.
Also, the shape is such that it is difficult to get scratched when released from the mold.

The holding frame 3 is made of a heat-resistant synthetic resin such as polyphenylene sulfide resin.
The distal end is tapered, and recesses 30 are formed on both sides.The recesses 30 are deep on the proximal end side of the holding frame 3 and shallow on the distal end side. A portion having a uniform thickness is formed between the recesses 30 . Furthermore, a plurality of circular holes 3 are formed in the area where the wall thickness is uniform.
1 is provided, and a pair of cylindrical portions 32 are provided protruding from the central portion of the base end. The above disc-shaped heating element 1
are positioned within each hole 31 in this holding frame 3. A pair of electrode plates 2 that are in contact with both surfaces of the heating element 1 are disposed in recesses 30 on both sides of the holding frame 3. Both electrode plates 2 are made of a good thermal conductor such as copper and have the same shape, and both have a wedge-shaped cross section with an inclined outer surface and a wall thickness that becomes thinner toward the tip. By integrally providing the terminal portion 20 at the end, the reliability of connection with the electrode wire 9 formed of a heat-resistant electric wire is increased. The electrode plate 2 is arranged in each recess 30 of the holding frame 3 and is positioned by a peripheral wall surrounding the recess 30, and each terminal portion 20 to which the electrode wire 9 is caulked is placed in each recess 30 of the holding frame 3.
They are insulated from each other by being inserted into the cylindrical portion 32 at. The holding frame 3 on which the heating element 1 and the pair of electrode plates 2 are arranged is covered on both sides with a heat-resistant adhesive film 7 made of polyimide amide resin or the like, and is further covered with a highly thermally conductive material such as alumina. Double insulation is achieved by covering with an insulating sheet 8 made of a heat-resistant and thermally conductive material such as a silicone rubber sheet.

The pair of heater blocks configured in this way are respectively installed in the two recesses 6 of the heat sink 5. At this time, each heater block is fitted with a pair of presser springs made of a heat-resistant metal such as stainless steel. 10, it is attached in a spring-biased state in the direction of insertion into the recess 6. A pair of recesses 6
A pair of presser metal fittings 13 are attached to the heat sink plate 5 with screws 12 whose tips are screwed into a pair of screw receiving bosses 11 provided between both recesses 6 on the bottom surface of the heat sink plate 5, and each heater block. The above-mentioned presser spring 10 is disposed between the base bottom surface of the holding frame 3 and the holding frame 3.
One end of the holding frame 3 is fitted into a protrusion 33 as a spring receiving part formed on the bottom surface of the base of the holding frame 3 to prevent misalignment and to stabilize the load. Each presser metal fitting 13 made of a heat-resistant metal such as the one shown in FIG.

Now, each heater block that has been inserted into the recess 6 and pushed in the insertion direction by a pair of presser springs 10 has an inclination of the inner wall of the recess 6, which is formed as a tapered groove. The outer surface of each electrode plate 2 having an inclination angle equal to the angle is in close contact with the inner surface of the recess 6 via the film 7 and the insulating sheet 8. Also, the recesses 3 on both sides of the holding frame 3
As is clear from FIGS. 8 and 9, the interval 0, that is, the wall thickness t ₁ of the portion where the hole 31 containing the heating element 1 is formed is made thinner than the thickness t ₂ of the heating element 1. In addition, each electrode plate 2 is finished as a flat surface by the component of the spring force of the presser spring 10 acting between the wedge-shaped electrode plate 2 and the inner wall of the tapered groove-shaped recess 5. The inner surface of the heating element 1 can surely contact the surface of the heating element 1 while maintaining sufficient contact pressure. Therefore, the heating element 1 efficiently generates heat, and this heat is reliably transmitted to the heat sink 5 for heating. Furthermore, from the perspective of the heating element 1, since the conditions from both sides to both inner walls of the recess 6 of the heat sink 5 are exactly the same, the amount of heat radiated from both sides of the heating element 1 is the same, and the heat generation element 1 generates heat. Since the internal temperature of the element 1 is made uniform and there is no uneven heat generation, the amount of heat generated as a whole increases. Since each heater block is provided with a plurality of heating elements 1, a large heat radiation area can be obtained compared to the area of the heating elements 1, and a high power heater can be obtained at a low cost. It is something.

Here, when the heater block is press-fitted into the recess 6 of the heat sink 5, the stress applied to the heat generating element 1 through the electrode plate 2 is high because the corners of the heat sink 5 are difficult to bend. There is a risk that the heating element 1, which has no ductility, will be destroyed. In order to prevent this, notches 15 are provided at the corners of the electrode plate 2 to prevent the electrode plate 2 from coming into contact with the corners of the heat sink 5.

[Effects of the Invention] As described above, in the present invention, the electrode plate inserted into the recess of the heat sink along with the heat generating element is wedge-shaped, and when the heat generating element and the electrode plate are inserted into the recess of the heat sink. The contact between the heating element and the electrode plate and the contact with the inner wall of the recess is ensured by the electrode plate, and the electrical contact between the heating element and the electrode plate and the contact between the heating element and the heat sink are ensured by the electrode plate. In addition, the heat generating element and the electrode plate do not shift position even if subjected to impact, and the electrode plate is wedge-shaped and other wedge-shaped members are not used. Because there are no heat sinks, the number of parts is reduced, and the number of heat transfer contact surfaces is also reduced, resulting in high thermal conductivity from the heating element to the heat sink, resulting in low thermal loss.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional example, Fig. 2 is a cutaway front view of an embodiment of the present invention, and Fig. 3 is a cutaway side view of the same.
FIG. 4 is a bottom view of the same as the above, FIG. 5 is an exploded perspective view of the same as the above, FIG. 6 is an exploded perspective view of the same as the above heater block, and FIGS. 7 to 9 are front views and A-- 1 is a heating element, 2 is an electrode plate, 5 is a heat sink,
6 indicates a recess, and 20 indicates a terminal portion.

Claims (1)

[Scope of Claims] 1. A heater in which a heating element made of a positive temperature coefficient thermistor and a pair of electrode plates are housed in a recess formed in a heat sink, where at least one electrode plate is formed in a wedge shape. A heater featuring: 2. The heater according to claim 1, wherein the electrode plate integrally has a terminal portion. 3. The heater according to claim 1, wherein the recess of the heat dissipation plate has a tapered groove shape with the groove width becoming narrower toward the back.