JPH0514470Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a positive temperature coefficient thermistor suitable for heating a rod-shaped object to be heated.
In a positive temperature coefficient thermistor device in which a pair of electrode terminals and a heat dissipation plate insulated and superimposed on one of the electrode terminals are supported and fixed to a case, the heat dissipation plate is provided with a protrusion that protrudes to the outside, and a heated object is attached to the protrusion. By forming a cylindrical portion to be thermally coupled, it is possible to provide a positive temperature coefficient thermistor device that can efficiently heat a rod-shaped heated object and is easy to manufacture, process, and assemble.

<Prior art> When heating a core rod in a liquid-type electric mosquito repellent, etc., in which insecticidal gas is released from the core rod by heating the outer periphery of the core rod into which an insecticidal liquid is permeated by capillary action. Conventionally, a positive temperature coefficient thermistor device has been used in which a doughnut-shaped positive temperature coefficient thermistor having a center hole is used, and a core rod is inserted into the center hole of the positive coefficient thermistor.

<Problems to be Solved by the Invention> As described above, in the conventional PTC thermistor device, it has been essential to use a doughnut-shaped PTC thermistor having a through hole. However, in donut-shaped positive temperature coefficient thermistors, the inner and outer diameters of the through holes fluctuate due to changes in shrinkage during firing, making it difficult to obtain the desired size and shape. There are problems such as having to form the electrodes so that they do not sag, which makes electrode formation troublesome, and the presence of through holes imposes restrictions on the shape and structure of the electrode terminal plate, making the electrode extraction structure complicated. There are other problems.

Therefore, an object of the present invention is to provide a positive temperature coefficient thermistor device that can efficiently heat a rod-shaped heated object and is easy to manufacture, process, and assemble.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention includes a case having a recess on one side, a positive temperature coefficient thermistor having electrodes on both sides in the thickness direction and housed in the recess, a pair of electrode terminals that are in contact with the electrodes of the PTC thermistor in the recess; a heat sink that is stacked on one of the electrode terminals with an electrically insulating plate interposed therebetween on the opening side of the recess; and the heat sink. A positive temperature coefficient thermistor device having a cover that is placed over the top and supporting and fixing the whole to a case, wherein the heat sink has a protruding portion and a cylindrical portion that serves as a thermally coupled portion of the heated body. The protrusion is formed into a flat plate shape that extends continuously from the overlapping surface with the insulating plate, and is provided to protrude outside the case, and the cylindrical part has a thickness that is greater than the thickness of the protrusion. The hole has a sufficiently long hole, the plate thickness is selected to be approximately the same as the plate thickness of the protrusion, and the outer peripheral surface is connected to the protrusion so as to be substantially continuous with the protrusion.

<Function> A case having a recess on one side, a positive temperature coefficient thermistor having electrodes on both sides in the thickness direction and housed in the recess, a pair of electrode terminals facing the electrodes of the positive temperature coefficient thermistor within the recess, and the recess. It has a heat dissipation plate that is stacked on one of the electrode terminals via an electrical insulating plate on the opening side, and a cover that is superimposed on the heat dissipation plate and supports and fixes the whole to the case.
All that is required is to use a flat positive temperature coefficient thermistor, place the positive temperature coefficient thermistor, electrode terminal plate, etc. in the recess of the case, stack a heat sink on top of it in an electrically insulated manner, and fix the whole thing with a cover. For this reason,
Manufacturing, processing and assembly become easier.

The protruding portion constituting the heat dissipation plate is formed into a flat plate shape that extends continuously from the overlapped surface with the insulating plate, and
The cylindrical part that protrudes from the outside of the case and serves as a thermally connected part to the object to be heated is connected to the protruding part, so it can be used as a liquid electric heater to heat the outer periphery of the core rod impregnated with insecticidal liquid. When forming a mosquito repellent or the like, a core rod can be inserted into the cylindrical part and heated outside the case.
The case and the electrode terminals, positive temperature coefficient thermistor, etc. incorporated therein can have a unique assembly structure that is most suitable for them, regardless of the core rod that is the object to be heated.

Since the cylindrical part has a hole that is sufficiently longer than the plate thickness of the protruding part, the plate thickness of the protruding part can be made thinner, its heat capacity can be reduced, and the heat transfer efficiency from the protruding part to the cylindrical part can be improved. A heat dissipation surface necessary for heating the object to be heated can be secured in the cylindrical portion.

The cylindrical part is selected to have a plate thickness that is almost the same as that of the protruding part, and is connected to the protruding part so that the outer peripheral surface is substantially continuous with the protruding part, so that the cylindrical part and the protruding part are Heat conduction occurs smoothly at the connecting portion between the two, improving heat conduction efficiency.

<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 perspective view, Fig. 3 is a sectional view taken along the line _A1 - _A1 in Fig. 2, and Fig. 4 is an exploded perspective view of a PTC thermistor device according to the present invention. Figure 2 A ₂
-A ₂ line sectional view, and FIG. 5 is a 3rd line A ₃ -A ₃ sectional view. In this embodiment, an elastic electrode terminal 9 made of a stainless steel plate or the like is arranged in a groove 8 of a case 7 made of a heat-resistant insulating material such as alumina, and is placed on both sides of the elastic electrode terminal 9 in the thickness direction. Electrode 11
A disk-shaped positive temperature coefficient thermistor 11 having 1,112 deposited thereon, and an electrode terminal 1 made of a stainless steel plate or the like.
2. A heat-resistant insulating plate 13 made of mica or the like, a heat sink 14 made of aluminum or the like, and a cover 15 made of stainless steel or the like are stacked one after another, and the cover 15 stacked on top of the heat sink 14 is connected to the elastic electrode terminal 9. By pressing in the direction of the case 7 while resisting the elastic force of the cover 15 and bending the mounting arms 151 to 154 provided on the cover 15 along the outer wall of the case 7, the entire structure is elastically supported and fixed. It's summery.

The heat dissipation plate 14 has a protrusion 141 that extends continuously from the overlapping surface with the insulating plate 13 to the outside of the case 7, and this protrusion 141 has a cylindrical part that becomes a thermal connection part with the heated object. 142 is formed.
The cylindrical portion 142 has a mounting hole 143 that passes through the protrusion 141 in the thickness direction. The length of the attachment hole 143 in the axial direction is sufficiently longer than the thickness of the protrusion 141 . Further, the cylindrical portion 142 has a plate thickness that is smaller than that of the protruding portion 141.
The thickness of the plate is selected to be approximately the same as that of the plate, and the outer peripheral surface is the protruding part 1.
41 and is coupled to protrusion 141 so as to be substantially continuous with protrusion 41 . The cylindrical portion 142 may be formed integrally with the protruding portion 141, or may be formed separately and attached later. Furthermore, the attachment hole 143 can be formed into an appropriate shape such as a circular shape, an elliptical shape, or a square shape, depending on the outer shape of the object to be heated.

FIG. 6 shows an example in which the positive temperature coefficient thermistor device according to the present invention is used in a liquid-type electric mosquito repellent, where 6 is a core rod through which the insecticidal liquid permeates, and 16 is a tank containing the insecticidal liquid 17. The core rod 6 is inserted into the hole 143 of the cylindrical portion 142.
At the same time, the lower end is immersed in an insecticidal liquid 17 in a tank 16.

Positive temperature coefficient thermistor 1 through electrode terminals 9 and 12
When a voltage is applied to the positive temperature coefficient thermistor 11, the positive temperature coefficient thermistor 11 performs a well-known constant temperature heating operation. Positive characteristic thermistor 1
The heat generated in the heat sink 1 is transferred to the heat sink 14 through the electrode terminal 12 and the insulating plate 13, and the core rod 6 provided in the cylindrical portion 142 of the heat sink 14 is heated, thereby dissipating the insecticidal gas.

As described above, according to the positive temperature coefficient thermistor device according to the present invention, the core rod 6 impregnated with the insecticidal liquid 17 is
It can be heated by being inserted into the cylindrical portion 142 of the heat sink 14 outside the case 7 . Therefore, the case 7, the electrode terminals 9 and 12, the positive temperature coefficient thermistor 11, and the like built into the case can have their own assembly structure independently of the core rod 6, which is the object to be heated. For example, the PTC thermistor 11 can be formed into a flat plate shape, which is easy to manufacture, instead of a donut shape. In addition, it is possible to stabilize the power supply to the PTC thermistor 11, and to stabilize the power supply from the PTC thermistor 11 to the heat sink
It is also easy to adopt a structure necessary for improving thermal conductivity and providing an overcurrent protection function to 4.

Since the cylindrical portion 142 has a hole 143 that is sufficiently longer than the plate thickness of the protruding portion 141, the plate thickness of the protruding portion 141 is made thinner and its heat capacity is lowered.
While improving the efficiency of heat transfer from the cylindrical portion to the cylindrical portion 142, a heat dissipation surface necessary for heating the object to be heated can be secured in the cylindrical portion 142.

The cylindrical portion 142 is selected to have a plate thickness that is approximately the same as that of the protruding portion 141, and is coupled to the protruding portion 141 such that the outer circumferential surface thereof is substantially continuous with the protruding portion 141. Heat conduction is performed smoothly at the connection portion between 142 and the protrusion 141, and heat conduction efficiency is improved.

Further, in this embodiment, the elastic electrode terminal 9 is configured as a leaf spring having an elastic electrode contacting portion 91 that presses into contact with the electrode 111 of the PTC thermistor 11, and a lead-out terminal portion 92 extending from the electrode contacting portion 91. It has been formed. Therefore, the positive temperature coefficient thermistor 11, electrode terminals 9, 12, insulating plate 13, and heat sink 14 are laminated in close contact with each other due to the elasticity of the electrode terminal 9, and the electrode terminals 9, 12 are stacked closely against the electrodes 111, 112 of the positive temperature coefficient thermistor 11. The electrical contact between the positive temperature coefficient thermistor 11 and the heat sink plate 14 is improved.

Next, the electrode terminal 12 connects the electrode contacting part 121 and the lead-out terminal part 122, which are in contact with the electrode 112 of the PTC thermistor 11, to a narrow part 122 formed at a distance on the side of the electrode contacting part 121. The structure is such that the narrow width portion 123 serves as an overcurrent fusing portion. If the PTC thermistor 11 deteriorates, an overcurrent will flow during thermal equilibrium, which should normally be a low current, resulting in extremely dangerous conditions such as damage to the PTC thermistor 11, abnormal heat generation, and accompanying fire. Therefore, in this embodiment, the electrode terminal 12 is provided with a narrow portion 123 that serves as an overcurrent fusing portion to provide overcurrent protection.

Furthermore, in accordance with the shape and structure of the electrode terminals 9 and 12 described above, the case 7 has a hole 71 (see FIG. 3) at the bottom through which the lead-out terminal portion 92 of the electrode terminal 9 passes.
and an open end surface 7 with a groove 8 opened therein.
2 is provided with a hole 73 through which the lead-out terminal portion 122 of the electrode terminal 12 passes, and the lead-out terminal portions 92, 122 of the electrode terminals 9, 12 are led out to the bottom side of the case 7 through the holes 71, 73.

A recess 74 is formed on the surface of the open end face 72 of the case 7 . The recessed portion 74 is formed at a position corresponding to the narrow width portion 123 of the electrode terminal 12 so as to be independent from the groove 8 . In the assembled state,
The narrow portion 123 of the electrode terminal 12 is located within the recess 74, and the narrow portion 123 of the electrode terminal 12 is closed with the insulating plate 13.
With this structure, when the narrow portion 123 is fused due to an overcurrent, the molten metal remains within the recess 74 and does not scatter into the recess 8 where the positive temperature coefficient thermistor 11 is located. Therefore, a short circuit between the electrodes 111 and 112 due to adhesion of molten metal to the outer circumferential surface of the PTC thermistor 11 can be prevented.

Further, a bent piece 124 is provided around the electrode terminal 12.
This bent piece 124 is attached to the end surface 72 of the case 7.
It is inserted and positioned within a recess 75 formed in the.
With such a structure, even if the narrow portion 123 is blown off by an overcurrent and the electrode contact portion 121 is separated from the lead-out terminal portion 122, the electrode contact portion 121 will remain in the correct position. There is no movement on the characteristic thermistor 11. Therefore, it is possible to prevent the electrode contact portion 121 from electrically contacting the fused end portion of the extraction terminal portion 122 after the overcurrent fusion occurs.

Further, a stepped portion 12 is provided above the pull-out terminal portion 122.
5, and this stepped portion 125 is connected to the case 7.
It is held between the end face 72 of and the insulating plate 13. With this structure, when an external force is applied to the pull-out terminal portion 122 in the assembled state, the external force is prevented from being transmitted to the narrow width portion 123, and the narrow width portion 123, which has weak mechanical strength, acts as the pull-out terminal. Damage due to external force applied to the portion 122 can be prevented.

FIG. 7 is a one-hour characteristic diagram of current and heat generation temperature of the PTC thermistor device according to the present invention. In the figure, curve A is a one-hour current characteristic, and curve B is a one-hour characteristic of heat generation temperature. The time axis is plotted on the horizontal axis, the current on the left vertical axis, and the heat generation temperature on the right vertical axis.
The heat generation temperature was measured by attaching a thermocouple to the approximate center of the inner surface of the cylindrical portion 142. The applied voltage was AC100V, and the ambient temperature was 23°C. Case 7, electrode terminal 9,
12. The following components were used, such as the positive temperature coefficient thermistor 11, the insulating plate 13, the heat sink 14, and the cover 15.

Case 7...Alumina electrode plates 9, 12...SUS 430 0.2tm/m Positive characteristic thermistor 11 Curie temperature Tc=220
℃ φ12.0×3tm/m disc-shaped Insulating plate 13...Mica plate 0.2tm/m Heat sink 14...Al 0.5tm/m Cover 15...SUS 430 0.4tm/m As shown in Figure 7 At thermal equilibrium, the heat generation temperature is approximately 132°C and the current is 0.49A (4.6W), resulting in a positive temperature coefficient thermistor device with low power consumption and high heat generation temperature. Moreover, the rise time is only a few minutes,
A positive temperature coefficient thermistor device with good thermal response has been obtained.

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

(a) A case having a recess on one side, a positive temperature coefficient thermistor having electrodes on both sides in the thickness direction and housed in the recess, a pair of electrode terminals facing the electrodes of the positive temperature coefficient thermistor within the recess, and the recess. It has a heat dissipation plate that is stacked on one of the electrode terminals via an electrical insulating plate on the opening side of the case, and a cover that is superimposed on the heat dissipation plate and supports and fixes the whole to the case, making it easy to manufacture, process, and assemble. A simple positive temperature coefficient thermistor device can be provided.

(b) The protruding part constituting the heat dissipation plate is formed into a flat plate shape that extends continuously from the overlapped surface with the insulating plate, and is provided so as to protrude outside the case, and serves as a thermal connection part with the heated object. Since the cylindrical part is connected to the protruding part, the case and the electrode terminals, positive temperature coefficient thermistors, etc. built into the case and the inside of the case can be heated in a unique manner that is most suitable for them, regardless of the core rod that is the heated body. This makes it possible to take an assembled structure, and it is possible to provide a positive temperature coefficient thermistor device that is easy to manufacture, process, and assemble.

(c) Since the cylindrical part has holes that are sufficiently longer than the plate thickness of the protruding part, the plate thickness of the protruding part can be made thinner to lower its heat capacity and improve the heat transfer efficiency from the protruding part to the cylindrical part. It is possible to provide a positive temperature coefficient thermistor device that can secure a heat dissipation surface necessary for heating the heated object in the cylindrical part and efficiently heat the rod-shaped heated object.

(d) The cylindrical part is selected to have a plate thickness that is approximately the same as that of the protruding part, and is connected to the protruding part so that the outer peripheral surface is substantially continuous with the protruding part. Heat conduction is carried out smoothly at the connection portion between the protrusion and the positive temperature coefficient thermistor device with high heat conduction efficiency can be provided.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of a positive temperature coefficient thermistor device according to the present invention, Fig. 2 is an assembled perspective view, Fig. 3 is a sectional view taken along line A ₁ - _{A 1} of Fig. 2, and Fig. 4 is Fig. 2 A ₂
-A ₂ line sectional view, Figure 5 is Figure 3A ₃ -A ₃ line sectional view, Figure 6 is a diagram showing an example of using the positive temperature coefficient thermistor device according to the present invention in a liquid electric mosquito repellent, FIG. 7 is a one-hour characteristic diagram of current and heat generation temperature of the PTC thermistor device according to the present invention. 7...Case, 9, 12...Electrode terminal, 11...
...Positive characteristic thermistor, 13...Insulating plate, 14...
heat sink, 141... protrusion, 142... cylindrical part,
15...Cover.

Claims (1)

[Claims for Utility Model Registration] (1) A case having a recess on one side, a positive temperature coefficient thermistor having electrodes on both sides in the thickness direction and housed in the recess, and a positive temperature coefficient thermistor in the recess. a pair of electrode terminals that are in contact with the electrodes; a heat sink that is stacked on one of the electrode terminals via an electrically insulating plate on the opening side of the recess; and a heat sink that is stacked on top of the heat sink and the whole is enclosed in a case. A positive temperature coefficient thermistor device having a cover for supporting and fixing, wherein the heat sink has a protrusion and a cylindrical part that serves as a thermally coupled part for a heated object, and the protrusion is connected to the insulating plate. The cylindrical part has a hole that is sufficiently longer than the thickness of the protruding part, and the cylindrical part has a hole that is sufficiently longer than the thickness of the protruding part. A positive temperature coefficient thermistor device, wherein the thickness is selected to be approximately the same as the plate thickness of the protrusion, and the positive temperature coefficient thermistor device is coupled to the protrusion so that the outer peripheral surface is substantially continuous with the protrusion. (2) The positive temperature coefficient thermistor device according to claim 1, wherein at least one of the two electrode terminals has a narrow portion that serves as an overcurrent fusing portion.