JP2022047552A - Temperature sensor - Google Patents

Abstract

To provide a downsized temperature sensor that ensures the stable bond strength of a thermistor element.SOLUTION: A temperature sensor has a pair of lead wires 2 with tip parts having exposed core wires 2a juxtaposed with each other, a thermistor element 3 having terminal electrodes 3a formed at both ends thereof, and a pair of metallic pipe members 4 with the core wires of the pair of the tip parts fixedly inserted thereinto. The pair of the terminal electrodes of the thermistor element are bonded to the pair of metallic pipe members with a conductive fusing agent 5. This downsizes the temperature sensor and provides a high bond strength compared to a case of directly bonding the thermistor element to the core wire of a twisted wire, as the pair of the terminal electrodes are connected to the metallic pipe member having higher strength than the twisted wire and a smooth bonding surface.SELECTED DRAWING: Figure 1

Description

The present invention relates to a temperature sensor that is easy to miniaturize and has high reliability.

Conventionally, as a temperature sensor that requires thermal responsiveness, there is one that measures the surface temperature of an automobile battery or the like.
In recent years, there has been a demand for size reduction of temperature sensors for such applications. For example, Patent Document 1 describes a temperature detection sensor in which a chip-type thermistor element is directly bonded to the core wire of a lead wire.
This temperature detection sensor is manufactured by embedding and fixing a thermistor element bonded to the core wire in a bottomed tubular outer case with an epoxy-based insulating resin.

Japanese Patent No. 3516204

The following problems remain in the above-mentioned conventional technology.
In the temperature detection sensor of Patent Document 1, the thermistor element is directly bonded to the core wire of the lead wire by soldering or the like, but since the core wire is a stranded wire, the joint surface has many irregularities and is bonded to the chip type thermistor element. There is a high possibility that the voltage will be insufficient, and there is a problem that the reliability will be lowered. Further, since the core wire is soft and easily bent, there is a possibility that the thermistor element may be peeled off from the joint surface when an external force or an impact is applied.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a temperature sensor that can be miniaturized and can obtain stable bonding strength of a thermistor element.

The present invention has adopted the following configuration in order to solve the above problems. That is, the temperature sensor according to the first invention includes a pair of lead wires having exposed core wires arranged in parallel with each other, a thermistor element having terminal electrodes formed at both ends, and a pair of the tip portions. It is provided with a pair of metal pipe members in which a core wire is inserted and fixed, and the pair of terminal electrodes of the thermistor element is joined to the pair of metal pipe members with a conductive fusion agent. It is a feature.

In this temperature sensor, a pair of terminal electrodes of the thermistor element are bonded to a pair of metal pipe members with a conductive fusion agent, so that the size can be reduced in the same way as simply mounting the thermistor element on a stranded wire. In addition, higher bonding strength can be obtained by joining to a metal pipe member that is stronger than the core wire and has a smooth joint surface, as compared to the case where the thermistor element is directly mounted on the core wire of the stranded wire. can. Further, by joining the thermistor element to a metal pipe member having a higher strength than the core wire, it is difficult to bend even if an external force is applied, and high impact resistance can be obtained. Furthermore, by joining the thermistor element to a metal pipe member with high thermal conductivity, the metal pipe member can collect the heat from the surroundings and efficiently conduct it to the thermistor element, resulting in highly accurate temperature measurement. Will be possible.

In the first invention, the temperature sensor according to the second invention includes a thermistor element and a sealing resin portion for internally sealing or accommodating the pair of the metal pipe members, and the sealing resin portion is the said. It is characterized by having a high thermal conductive resin portion formed of a resin having higher thermal conductivity than other portions by being in direct contact with the thermistor element and being partially exposed to the outside.
That is, in this temperature sensor, the encapsulating resin portion has a highly thermally conductive resin portion formed of a resin that is in direct contact with the thermistor element and is partially exposed to the outside and has higher thermal conductivity than the other portions. Therefore, by bringing the high thermal conductive resin portion of the portion exposed to the outside into contact with the object to be measured, the heat of the object to be measured can be efficiently guided to the thermistor element.

The temperature sensor according to the third invention is characterized in that, in the first or second invention, the thermistor element is installed on the outer peripheral surface of the pair of the metal pipe members.
That is, in this temperature sensor, since the thermistor element is installed on the outer peripheral surface of the pair of metal pipe members, the temperature sensor can be used when the object to be measured is arranged on the outer peripheral surface side of the metal pipe member. It is easy to get closer to the object to be measured.

The temperature sensor according to the fourth invention is characterized in that, in the first or second invention, the thermistor element is installed on the tip surface of the pair of the metal pipe members.
That is, in this temperature sensor, since the thermistor element is installed on the tip surface of the pair of metal pipe members, the whole can be formed thin and can be inserted and installed in a narrow place.

The temperature sensor according to the fifth aspect of the invention is characterized in that, in any one of the first to third aspects, the metal pipe member is made of Cu or a Cu alloy.
That is, in this temperature sensor, since the metal pipe member is made of Cu or Cu alloy, heat can be transferred to the thermistor element more efficiently due to its high thermal conductivity. Further, good bonding strength can be obtained in terms of bonding property with the thermistor element.

According to the present invention, the following effects are obtained.
That is, according to the temperature sensor according to the present invention, since the pair of terminal electrodes of the thermistor element are bonded to the pair of metal pipe members with a conductive fusion agent, the size can be reduced and the core wire can be used. High joint strength can be obtained by joining to a metal pipe member having high strength and a smooth joint surface.
Therefore, in the temperature sensor of the present invention, the installation space can be small, and high impact resistance and the like can be obtained due to the high bonding strength of the thermistor element.

It is a top view which shows the 1st Embodiment of the temperature sensor which concerns on this invention. FIG. 3 is a cross-sectional view taken along the line AA of FIG. In the first embodiment, it is a top view which shows the lead wire and a metal pipe member, and is partially cut away. It is a perspective view which shows the temperature sensor in 1st Embodiment. It is a top view which shows the 2nd Embodiment of the temperature sensor which concerns on this invention. In the second embodiment, it is the left side view which shows the temperature sensor. In the second embodiment, it is a perspective view which shows the temperature sensor.

Hereinafter, the first embodiment of the temperature sensor according to the present invention will be described with reference to FIGS. 1 to 4. In each drawing used in the following description, the scale is appropriately changed in order to make each member recognizable or easily recognizable.

As shown in FIGS. 1 and 2, the temperature sensor 1 of the present embodiment is a thermistor in which a pair of lead wires 2 having exposed core wires 2a arranged in parallel with each other and terminal electrodes 3a formed at both ends thereof. It includes an element 3 and a pair of metal pipe members 4 in which a pair of tip core wires 2a are inserted and fixed inside.
The pair of terminal electrodes 3a of the thermistor element 3 are joined to the pair of metal pipe members 4 with a conductive fusion agent 5.

Further, the temperature sensor 1 of the present embodiment includes a sealing resin portion 6 that internally seals or stores the thermistor element 3 and the pair of metal pipe members 4.
The sealing resin portion 6 has a high thermal conductive resin portion 7 made of a resin that is in direct contact with the thermistor element 3 and is partially exposed to the outside and has higher thermal conductivity than the other portions. That is, as shown in FIG. 4, the high thermal conductive resin portion 7 is formed in a state where a part of the high thermal conductive resin portion 7 is exposed on the outer peripheral surface of the sealing resin portion 6.
The thermistor element 3 is installed on the outer peripheral surface of a pair of metal pipe members 4.
The metal pipe member 4 is made of Cu or a Cu alloy.
The pair of metal pipe members 4 are separated from each other, and the insulating resin of the sealing resin portion 6 is interposed between the pair of metal pipe members 4.

The lead wire 2 includes a core wire 2a which is a stranded wire and an insulating covering portion 2b made of a resin or the like that covers the outer periphery of the core wire 2a.
Further, as shown in FIG. 3, the metal pipe member 4 is caulked at at least one place with the tip portion where the core wire 2a is exposed inserted inside, and the caulking portion 4a tightly fixed to the core wire 2a is formed. Has been done.
The inside of the metal pipe member 4 and the core wire 2a are solder-plated, respectively, and after the caulking, heat treatment is performed to bond the metal pipe member 4 and the core wire 2a to each other by soldering.

The thermistor element 3 is a chip thermistor in which terminal electrodes 3a are formed at both ends.
The conductive fusion agent 5 is, for example, solder or the like.
The sealing resin portion 6 is formed by sealing a pair of metal pipe members 4 on which the thermistor element 3 is mounted and insert-molding them with an epoxy resin or the like.
A molded product having a pair of holes into which the pair of metal pipe members 4 can be inserted may be used as the sealing resin portion 6.

In this case, a molded product provided with a hole for the element for the thermistor element 3 and the high heat conductive resin portion 7 and a pair of pipe holes into which the pair of metal pipe members 4 can be inserted is used as the sealing resin portion 6 in advance. Make it.
Then, a pair of metal pipe members 4 to which the core wires 2a of the lead wires 2 are joined are inserted into the pair of pipe holes, and a part of the outer peripheral surface of the pair of metal pipe members 4 is exposed in the element holes. In this state, the thermista element 3 is bonded to the outer peripheral surfaces of the pair of metal pipe members 4 with the conductive fusion agent 5.

After that, the temperature sensor 1 is manufactured by embedding the high thermal conductive resin portion 7 in the element hole and sealing the thermistor element 3.
In the case of this manufacturing method, since the pair of pipe holes are formed in the sealing resin portion 6 in advance, it is possible to prevent the pair of metal pipe members 4 from coming into contact with each other.

When the other part of the sealing resin part 6 is made of epoxy resin, the high heat conductive resin part 7 is formed of, for example, a silicone resin having higher heat conductivity than the epoxy resin, a resin containing a high heat conductive insulating filler, or the like. Has been done.

As described above, in the temperature sensor 1 of the present embodiment, since the pair of terminal electrodes 3a of the thermistor element 3 are bonded to the pair of metal pipe members 4 with the conductive fusion agent 5, the thermistor is simply attached to the stranded wire. A metal pipe member that can be miniaturized in the same way as mounting an element, and has higher strength and a smoother joint surface than the core wire 2a as compared with the case where the thermistor element 3 is directly bonded to the core wire 2a of the stranded wire. By joining to 4, high joining strength can be obtained.

Further, by joining the thermistor element 3 to the metal pipe member 4 having a higher strength than the core wire 2a, it is difficult to bend even if an external force is applied, and high impact resistance can be obtained. Further, by joining the thermistor element 3 to the metal pipe member 4 having high thermal conductivity, the metal pipe member 4 can collect the heat of the surroundings and efficiently conduct the heat to the thermistor element 3, which is high. Accurate temperature measurement is possible.
In particular, since the metal pipe member 4 is made of Cu or a Cu alloy, heat can be transferred to the thermistor element 3 more efficiently due to its high thermal conductivity. Further, good bonding strength can be obtained in terms of bondability with the thermistor element 3.

Further, since the sealing resin portion 6 has a high thermal conductive resin portion 7 formed of a resin having a direct contact with the thermistor element 3 and a part exposed to the outside and having a higher thermal conductivity than the other portions. By bringing the high thermal conductive resin portion 7 of the portion exposed to the outside into contact with the object to be measured, the heat of the object to be measured can be efficiently guided to the thermistor element 3.
Further, since the thermistor element 3 is installed on the outer peripheral surface of the pair of metal pipe members 4, it is easy to mount the temperature sensor 1 when the object to be measured is arranged on the outer peripheral surface side of the metal pipe member 4. ..

Next, a second embodiment of the temperature sensor according to the present invention will be described below with reference to FIGS. 5 to 7. In the following description of each embodiment, the same components described in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The difference between the second embodiment and the first embodiment is that in the first embodiment, the thermistor element 3 is installed on the outer peripheral surface of the pair of metal pipe members 4, whereas the temperature of the second embodiment is high. In the sensor 21, as shown in FIGS. 5 to 7, the thermistor element 3 is installed on the tip surface of the pair of metal pipe members 4.

That is, in the second embodiment, the thermistor element 3 is joined by the conductive fusion agent 5 so as to straddle the flat tip surfaces of the pair of metal pipe members 4. Therefore, the element hole formed on the upper surface of the sealing resin portion 6 of the first embodiment is formed on the tip surface of the sealing resin portion 26, and the high heat conductive resin portion 27 is also embedded on the tip surface side. ..

As described above, in the temperature sensor 21 of the second embodiment, since the thermistor element 3 is installed on the tip surface of the pair of metal pipe members 4, the whole can be formed thin and inserted in a narrow place. It will be possible to install.

The technical scope of the present invention is not limited to each of the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, in the first embodiment, the thermistor element is mounted on the outer peripheral surface (curved surface) of the pair of metal pipe members, but the mounted portion on the outer peripheral surface of the pair of metal pipe members may be processed flat. In this case, the mounting is performed on a flat surface, and more stable and strong thermistor element bonding can be obtained.

1,21 ... Temperature sensor, 2 ... Lead wire, 2a ... Core wire, 3 ... Thermistor element, 3a ... Terminal electrode, 4 ... Metal pipe member, 5 ... Conductive fusion agent, 6,26 ... Sealing resin part, 7,27 ... High thermal conductivity resin part

Claims (5)

A pair of lead wires with exposed core wires arranged in parallel with each other,
Thermistor elements with terminal electrodes formed on both ends,
It is provided with a pair of metal pipe members in which the core wire of the tip portion is inserted and fixed inside.
A temperature sensor characterized in that a pair of terminal electrodes of the thermistor element are bonded to the pair of metal pipe members with a conductive fusion agent. In the temperature sensor according to claim 1,
A sealing resin portion for internally sealing or accommodating the thermistor element and the pair of metal pipe members is provided.
The sealing resin portion is characterized by having a highly thermally conductive resin portion formed of a resin having a part exposed to the outside and having a higher thermal conductivity than the other portions while being in direct contact with the thermistor element. Temperature sensor. In the temperature sensor according to claim 1 or 2.
A temperature sensor characterized in that the thermistor element is installed on the outer peripheral surface of the pair of metal pipe members. In the temperature sensor according to claim 1 or 2.
A temperature sensor characterized in that the thermistor element is installed on the tip surfaces of the pair of metal pipe members. In the temperature sensor according to any one of claims 1 to 3.
A temperature sensor characterized in that the metal pipe member is made of Cu or a Cu alloy.

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