JPH0515750Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a positive temperature coefficient thermistor device suitable for use in a mosquito trap using an insecticidal liquid vaporization method.

<Prior art> Mosquito traps that use vaporized insecticidal liquid to emit insecticides suck up insecticidal liquid using a water-absorbing suction core made of a fibrous material such as felt, heat the suction core,
It is designed to vaporize the insecticidal liquid. As a heating means for the suction core, a positive temperature coefficient thermistor is used, which is safe and highly reliable without the risk of overheating. FIG. 12 is a diagram schematically showing the structure of a conventional mosquito repellent of this type, in which 1 is an insecticidal bottle containing an insecticidal liquid, 2 is an outer container that holds the insecticidal bottle 1, 3 is a heating element, and 4 is a It is an outer container that serves as a lid.

The upper end of the insecticidal bottle 1 projects the upper end of a suction core A made of a fibrous material such as felt whose lower end is immersed in the insecticidal liquid inside the insecticide bottle 1. A top plate portion 41 of the outer container 4 is provided with holes 42 for dispersing the vaporized insecticidal liquid.

The heating element 3 has a donut shape with a hole 31 in the center, and when the outer container 4 is connected to the upper end of the outer container 2, the suction core A is inserted into the hole 31 of the heating element 3. The suction core A is heated by the heating element 3, and the insecticidal liquid sucked up by the suction core A is vaporized and diffused.

FIG. 13 is a sectional view of a conventional heating element 3, and FIG. 14 is an exploded perspective view thereof. 3
2 is a positive temperature coefficient thermistor, 33 is a case, 34 is a case lid member, and 35 is a heat radiation cylinder made of metal such as aluminum. The positive temperature coefficient thermistor 32 has a through hole 321 penetrating in the plate thickness direction.
It has a donut shape with electrodes 322 and 323 provided on both sides with openings, and electrode plates 36 and 37 are stacked on each of the electrodes 322 and 323, respectively.

The case 33 is made of a heat-resistant plastic material that is an electrical insulator, and has an inner cylindrical portion 332 protruding approximately from the center of a bottom portion 331 . The positive temperature coefficient thermistor 32 is housed in an annular groove 334 formed between the inner cylinder part 332 and the outer wall part 333, with the through hole 321 being fitted into the inner cylinder part 332 of the case 33. The opening surface of the case 33 is covered with a case lid member 3 made of a similar heat-resistant plastic material.
It is blocked at 4.

Then, the heat dissipation cylinder 35 made of a metal material such as aluminum is penetrated through the through hole provided in the inner cylinder part 332 of the case 33 and the case lid member 34, and both ends of the heat dissipation cylinder 35 are pushed outward. It is unfolded and fixed to the lower surface of the bottom 331 of the case 33 and the upper surface of the case lid member 34 by caulking.

<Problems to be solved by the invention> However, the conventional positive temperature coefficient thermistor device has the following problems.

(a) The doughnut-shaped positive temperature coefficient thermistor 32 is difficult to form electrodes on. In forming the electrodes 322 and 323, for example, electroless Ni plating is applied to the entire surface of the positive temperature coefficient thermistor body, and after the necessary annealing heat treatment is applied, the conductive layer deposited on the inner wall surface of the through hole 321 is It must be removed by polishing or other means. This process of removing the conductive layer is extremely troublesome and requires a long time.

(b) Instead of polishing, there is also a method of removing unnecessary parts of the conductive layer by chemical etching.
In this case, the characteristics of the positive temperature coefficient thermistor body and electrodes are deteriorated due to chemicals such as etching treatment liquid.

(c) Electrodes 322 and 323 of the positive temperature coefficient thermistor 32
The directions of the heat dissipating cylinder 35 passed through the through hole 321 and the inner cylinder part 332 are different from each other by approximately 90 degrees. Because of this angle difference, the heat generated on the electrodes 322, 323 side of the PTC thermistor 32 is transmitted from the electrode plates 36, 37 to the bottom 331 of the case 33 and the lid 34, and then takes a 90 degree curved path. It becomes a heat conduction path leading to the inner cylinder part 321. For this reason, there is a problem that there is a delay in heat transfer and a lack of quick response.

Therefore, the object of this invention is to enable the use of a flat plate-shaped PTC thermistor that is easy to manufacture and inexpensive, and to increase the degree of thermal coupling between the PTC thermistor and the heat transfer body, so that the heating surface It is an object of the present invention to provide a positive temperature coefficient thermistor device which can uniformize the temperature distribution on the inner wall surface of a cylinder over the entire circumference and improve the vaporization and diffusion efficiency of an insecticidal liquid.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides a positive temperature coefficient thermistor device including a heat transfer body, a heat dissipation cylinder, and a positive temperature coefficient thermistor, the heat transfer body comprising: It has a cylindrical part and a groove, the cylindrical part has an inner diameter hole penetrating from one side to the other side, and at least two flat parts at opposing positions on the outer circumferential surface, and the groove is on one side. is provided on the outside of the flat part, and the heat dissipation cylinder is closely inserted into the inner diameter hole of the cylinder part, and the inner wall surface is used as a heat generating surface, and the positive characteristic is At least two thermistors are provided, each of which is formed into a flat plate having electrodes on both sides in the thickness direction, and is disposed in the groove, and the electrode surface side is surface-coupled to each of the flat parts. .

<Function> The heat transfer body has an inner diameter hole penetrating from one side to the other side in the cylindrical part, and has flat parts at opposite positions on the outer circumferential surface, and a groove is provided on the outside of the flat part on the one side. Since the positive temperature coefficient thermistor is placed in the groove and the electrode side is surface-coupled to the flat part,
Heat generated on the electrode surface of the positive temperature coefficient thermistor is efficiently transferred to the cylindrical portion of the heat transfer body due to the surface coupling between the electrode surface and the flat portion provided on the heat transfer body.

Since the heat dissipation cylinder is tightly inserted into the inner diameter hole of the cylinder, the heat generated in the positive temperature coefficient thermistor is
The heat is efficiently transmitted from the cylindrical portion of the heat transfer body to the heat radiating cylinder. The inner wall surface of the heat radiation cylinder is used as a heat generating surface. Therefore, a positive temperature coefficient thermistor device with high efficiency and quick response can be obtained.

The heat transfer body has at least two flat portions at opposing positions on the outer circumferential surface of the cylindrical portion, and at least two positive temperature coefficient thermistors are provided, and the electrode surface side of each is surface-bonded to each of the flat portions.
The inner wall surface of the heat dissipating cylinder, which serves as the heat generating surface, is heated by the conductive heat so as to have a uniform temperature distribution all around.

Since a positive temperature coefficient thermistor is formed in a flat plate shape with electrodes on both sides in the thickness direction, it is different from a donut-shaped positive temperature coefficient thermistor with a through hole.
No work such as electrode removal is required. Therefore, by facilitating the manufacture, stabilizing the characteristics, and reducing the cost of the positive temperature coefficient thermistor, it is possible to obtain a positive temperature coefficient thermistor device that is easy to manufacture and assemble, has excellent characteristics, and is inexpensive.

<Example> Fig. 1 is an exploded perspective view of a positive temperature coefficient thermistor device according to the present invention, Fig. 2 is an assembled external perspective view, Fig. 3 is an enlarged sectional view, and Fig. 4 is Fig. 3 A ₁ -
It is a cross-sectional view on line _A1 . In the figure, 5,
6 is a positive temperature coefficient thermistor, 7 is a case, 8 is a metal heat dissipation cylinder, 9 and 10 are electrode terminals, 11 is a lid, and 12 is a holding metal fitting.

The positive temperature coefficient thermistors 5 and 6 have a disk shape with electrodes (51, 52) and (61, 62) provided on both sides in the thickness direction. Such flat positive temperature coefficient thermistors 5 and 6 have electrodes (51, 52) and (61, 62).
can be formed by printing, coating, baking, etc.
Unlike donut-shaped positive temperature coefficient thermistors having through holes, there is no need to remove the electrodes by polishing or chemical etching. Therefore, manufacturing is easy, and the characteristics do not deteriorate during electrode formation.

The case 7 is made of an electrical insulator with good thermal conductivity, such as alumina porcelain or heat-resistant plastic, and contains the storage case and the positive temperature coefficient thermistors 5 and 6.
It is also used as a heat transfer body to transfer the heat generated in the process. A cylindrical portion 72 having an inner diameter hole 71 penetrating in the axial direction is formed in the center of the case 7. A flat cylindrical portion 72 is formed on the outer wall of the cylindrical portion 72 so as to face each other across the cylindrical portion 72. The positive temperature coefficient thermistors 5 and 6 are surface-coupled to the flat parts 721 and 722, respectively. Furthermore, a groove 73 is provided around the cylindrical portion 72 of the case 7 to accommodate the positive temperature coefficient thermistor 5, 6, electrode terminals 9, 10, and the like. The groove 73 is closed by the lid 11.

A heat dissipating cylinder 8 made of aluminum or the like is tightly inserted into the inner diameter hole 71 of the cylindrical part 72, and the inner wall surface 81 of the heat dissipating cylinder 8 is connected to a suction core (first
(See Figure 2) is now used as a heat generating surface. Both ends of the heat dissipating cylinder 8 are fixed to the bottom surface of the case 7 and the surface of the holding fitting 12 by caulking, thereby tightening and fixing the entire body. Since the heat radiation cylinder 8 is tightly inserted into the inner diameter hole 71 of the cylinder part 72, the degree of thermal coupling between the two 72 and 8 is extremely high.

The electrode terminals 9 and 10 are made of a conductive material with high springiness, such as a thin stainless steel plate. The electrode terminal 9 has flat parts 91 and 92 facing each other, which are overlapped in surface contact with the flat parts 721 and 722 of the cylindrical part 72, and a connecting part 93 is connected between the flat parts 91 and 92.
, and a terminal portion 94 is integrally formed continuously with the connecting portion 93 . And flat part 7
21, 722 in surface contact and overlapped plane part 9
Positive temperature coefficient thermistors 5 and 6 are disposed above 1 and 92 so that electrodes 51 and 61 are in contact with each other.

On the other hand, the electrode terminal 10 has both ends curved to form contact parts 101 and 102 having spring properties, and the contact parts 101 and 102 are connected by a connecting part 103, and continuously from this connecting part 103, Terminal part 1
It has a structure derived from 04. Then, using the spring properties of the contact parts 101 and 102, the positive temperature coefficient thermistors 5 and 6 are connected to the flat parts 91 and 9 of the electrode terminals 9.
2, the flat parts 721, 722 of the cylindrical part 72 are brought into close thermal contact with the contact parts 101, 102.
Due to the springiness of the flat parts 91 and 92 of the electrode terminal 9,
The electrodes 51 and 61 of the positive temperature coefficient thermistors 5 and 6 are brought into close contact with each other to provide electrical continuity, and the contact portion 1
01 and 102 are electrodes 5 of positive temperature coefficient thermistors 5 and 6.
2 and 62 to make them electrically conductive. The terminal portions 94, 104 of the electrode terminals 9, 10 are drawn out from the bottom of the groove 73, thereby allowing connection with the outside. The groove 73 is closed by the lid 11. The joint surface between the lid and the case 7 and the drawer portions of the terminal parts 94 and 104 are sealed with adhesive to prevent the insecticidal liquid from entering the inside of the case 7.

As described above, when the PTC thermistors 5 and 6 are surface-coupled to the flat parts 721 and 722, the heat generated on the surfaces of the electrodes 51 and 61 of the PTC thermistors 5 and 6 is transferred to the flat parts 721 and 722 of the cylindrical part 72. 722 efficiently. A heat dissipating cylinder 8 having good thermal conductivity is inserted into the inner diameter hole 71 of the cylinder part 72.
The heat transferred to the cylindrical portion 72 is quickly transferred to the heat dissipation cylindrical body 8 from its inner wall surface. Moreover, since the heat dissipation cylinder 8 exhibits uniform high thermal conductivity over its entire circumference, it is heated so that the temperature distribution is uniform over the entire circumference of the inner wall surface of the heat dissipation cylinder.

The flat parts 721 and 722 are formed on the outer wall of the cylindrical part 72 so as to face each other with the cylindrical part 72 in between. Therefore, the outer periphery of the cylindrical portion 72 is heated at two points separated by an angle of 180 degrees. Therefore, the temperature distribution on the inner wall surface 81 of the heat dissipation cylinder 8 is made more uniform.

FIG. 9 shows the angle-heat generation temperature data of the positive temperature coefficient thermistor device according to the present invention. The angle θ is an angle measured along the inner circumference of the heat dissipation cylinder 8, and as shown in FIG. Measured clockwise or counterclockwise. L ₁ is the characteristic when the heat dissipation cylinder 8 is present (the present invention), and L ₂ is the characteristic when the heat dissipation cylinder 8 is not present.

FIG. 10 shows the time-temperature diagram of the positive temperature coefficient thermistor device according to the present invention. In the current data, L ₃ is the characteristic at point A, L ₄ is the characteristic at point B, which is 90 degrees away from point A.
L ₅ is the time-current characteristic.

As a positive characteristic thermistor device, Figs.
In the structure of the diagram, each component is set as follows.

<Positive characteristic thermistor 5, 6> A disc with a diameter of 4.5 mm and a thickness of 35 mm, with a Kyrie point of 160°C and a resistance value (25°C) of 1KΩ.

<Case 7> The cylindrical portion 72 is made of alumina porcelain and has an inner diameter of 11 mm, an outer diameter of 23 mm, and a height of 10 mm.

<Heat radiation cylinder 8> Aluminum with an inner diameter of 10 mm and a wall thickness of 0.3 mm <Electrode terminals 9, 10> Stainless steel plate with a plate thickness of 0.2 mm <Cover body 11> Alumina porcelain plate <Holding bracket 12> Stainless steel plate with a plate thickness of 0.5 mm As is clear from the curve _L2 in Figure 9, when there is no heat dissipation cylinder, the temperature changes significantly from 121.7℃ at point A to 104.1℃ at point B, which is 90 degrees away from point A. In the PTC thermistor device according to the present invention in which the body 8 is inserted, the temperature is uniform at 116.6° C. over the entire circumference of the inner wall surface 81 of the heat dissipating cylinder 8 which is the heat generating surface. Therefore, according to the present invention, an insecticide liquid suction wick is inserted into the heat dissipation cylinder 8,
When vaporizing the insecticidal liquid, the suction wick can be heated uniformly from its entire circumference and vaporized efficiently.

Furthermore, as is clear from the curves L ₃ and L ₄ in FIG. 10, substantially the same time-temperature characteristics are obtained at point A, which is closest to the positive temperature coefficient thermistors 5 and 6, and point B, which is farthest.

FIG. 5 is an exploded perspective view of another embodiment of the PTC thermistor device according to the present invention, FIG. 6 is an enlarged front sectional view of the same in the assembled state, and FIG. FIG. In the figures, the same reference numerals as in FIGS. 1 to 4 indicate the same components. A feature of this embodiment is that bent pieces 911, 912, 921, 922 are provided at both ends of the flat parts 91, 92 of the electrode terminal 9, which are bent in the direction of the PTC thermistors 5, 6. The electrode terminal 9 is formed by means such as press punching, and burrs are generated at the edge portion. If there is a burr like this,
Positive temperature coefficient thermistors 5 and 6 are placed on the flat parts 91 and 92.
, the positive temperature coefficient thermistors 5 and 6 may ride on the burr, resulting in poor adhesion and poor thermal conductivity. When the bent pieces 911, 912, 921, and 922 as shown in this embodiment are provided, the burrs formed on the edges of the bent pieces 911, 921, and 922 are removed.
Since the positive temperature coefficient thermistors 5 and 6 are included in the regions 912, 921, and 922, the degree of thermal coupling can be increased by bringing the positive temperature coefficient thermistors 5 and 6 into close contact with the flat parts 91 and 92.

Another feature of this embodiment is that the electrode terminals 9,
10 terminal parts 94, 104 are drawn out from the side where the lid body 11 is located. This type of positive temperature coefficient thermistor device is used for vaporizing chemical liquids such as insecticidal liquid, and if the sealing is insufficient, the elements of the internal positive temperature coefficient thermistors 5 and 6, the electrodes 51,
This results in deterioration of the contact portions between the positive temperature coefficient thermistors 5 and 6 and the electrode terminals 9 and 10, resulting in loss of reliability. With the structure shown in the embodiment, the drawer portions of the terminal portions 94 and 104, which need to be sealed against the inside of the case 7,
Since the joints between the lid 11 and the case 7 are located on the same side, the sealing work by applying adhesive becomes easier, and at the same time sealing can be performed reliably, improving reliability. .

FIG. 8 shows a sectional view of another embodiment of the positive temperature coefficient thermistor device according to the present invention. In this embodiment, the cylindrical portion 72 is formed from a separate member independent from the case 7. Therefore, in the case of this embodiment, the cylindrical portion 72 is made of a member having better thermal conductivity than the case 7, and the thermal conductivity can be further improved.

Although not shown, the flat portion 7 provided in the cylindrical portion 72
21 and 722 are not limited to opposing positions with the cylindrical part 72 in between, but may also be provided, for example, at a collar part bent 90 degrees from the opposing position. Also,
The number of positive temperature coefficient thermistors 5 and 6 is not limited to two, but a larger number may be provided.

<Effects of the invention> As described above, according to the invention, the following effects can be obtained.

(a) The heat transfer body has an inner diameter hole passing through the cylinder from one side to the other side, and has a flat part on the outer peripheral surface, and a groove is provided on the outside of the flat part on the one side, The heat dissipation cylinder is tightly inserted into the inner diameter hole of the cylinder part, and the inner wall surface is used as a heat generation surface, and the positive temperature coefficient thermistor is placed in the groove, and the electrode surface side is surface-coupled to the flat part. Therefore, the heat generated on the electrode surface of the PTC thermistor is efficiently transferred to the cylindrical portion of the heat transfer body due to the surface coupling between the electrode surface and the flat part provided on the heat transfer body, and the heat transfer is Heat is efficiently transmitted from the cylindrical portion of the body to the radiating cylindrical body, and a positive temperature coefficient thermistor device with high efficiency and quick response can be obtained.

(b) The cylindrical part of the heat transfer body has at least two flat parts at opposing positions on the outer peripheral surface, and at least two positive temperature coefficient thermistors are provided, each electrode surface side being surface-coupled to each of the flat parts. Therefore, it is possible to provide a positive temperature coefficient thermistor device that can heat the inner wall surface of the heat dissipating cylinder, which is the heat generating surface, so as to have a uniform temperature distribution over its entire circumference.
When used in a mosquito trap using an insecticidal liquid vaporization type, a positive temperature coefficient thermistor device that can promote the efficiency of insecticidal liquid vaporization and emission can be provided.

(c) Since a positive temperature coefficient thermistor is formed into a flat plate with electrodes on both sides in the thickness direction, it is easy to manufacture and assemble the positive temperature coefficient thermistor, stabilizing its characteristics, and reducing costs. An inexpensive positive temperature coefficient thermistor device with excellent cost can be obtained.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of a PTC thermistor device according to the present invention, Fig. 2 is an assembled external perspective view, Fig. 3 is an enlarged sectional view, and Fig. 4 is Fig. 3 A ₁ -
₅ is an exploded perspective view of another embodiment of the PTC thermistor device according to the present invention, FIG. 6 is an enlarged front sectional view of the same in the assembled state, and FIG. 7 is the same as the lid body. 8 is a sectional view of another embodiment of the PTC thermistor device according to the present invention, and FIG. 9 is a diagram of the angle-heat generation temperature characteristic of the PTC thermistor device according to the present invention. , FIG. 10 shows the time-temperature graph of the positive temperature coefficient thermistor device according to the present invention. Current characteristic diagram, Figure 11 is a diagram showing the measurement conditions of Figures 9 and 10, Figure 12
The figure is a diagram schematically showing the structure of a conventional mosquito repellent.
FIG. 3 is a sectional view of a conventional positive temperature coefficient thermistor device used in a mosquito repellent, and FIG. 14 is an exploded perspective view thereof. 5, 6...Positive characteristic thermistor, 7...Case,
72... Cylindrical part, 721, 722... Flat part, 8...
...heat dissipation cylinder.

Claims (1)

[Claims for Utility Model Registration] (1) A positive temperature coefficient thermistor device including a heat transfer body, a heat radiation cylinder, and a positive temperature coefficient thermistor, wherein the heat transfer body has a cylinder portion and a groove. , the cylindrical part has an inner diameter hole penetrating from one side to the other side, and at least two flat parts at opposing positions on the outer peripheral surface, and the groove is provided on the outside of the flat part on the one side. The heat dissipating cylinder is tightly inserted into the inner diameter hole of the cylinder part, and the inner wall surface is used as a heat generating surface, and at least two positive temperature coefficient thermistors are provided, A positive temperature coefficient thermistor device, each of which is formed in a flat plate shape having electrodes on both sides in the thickness direction, and is disposed in the groove, and the electrode surface side is surface-coupled to each of the flat parts. (2) the positive temperature coefficient thermistor includes an electrode terminal;
The positive temperature coefficient thermistor device according to claim 1, wherein the electrode terminal is brought into pressure contact with the flat portion of the heat transfer body by a spring pressure of the electrode terminal. (3) The PTC thermistor device according to claim 1 or 2, wherein the heat transfer body includes a lid, and the lid closes the groove. (4) The positive temperature coefficient thermistor device according to claim 3, wherein the terminal portion of the electrode terminal is drawn out from the bottom of the groove. (5) The positive temperature coefficient thermistor device according to claim 3, wherein the terminal portion of the electrode terminal is drawn out from the lid side.