JP3609202B2 - Heat-resistant electric wire and terminal treatment method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-resistant electric wire and a terminal treatment method thereof, and relates to a heat-resistant electric wire in which an insulating coating covering a conductive wire is formed from glass fibers such as a glass fiber bundle (glass fiber tape) and a glass fiber braid.
[0002]
[Background]
In a general electric wire using a material such as vinyl coating or rubber as a material of the insulation coating, the insulation coating is softened or deteriorated at a temperature of about 180 ° C. Also, under such temperature conditions, there is anxiety over long-term use even when an insulating coating made of a polyimide heat-resistant plastic is used. With respect to these electric wires, the electric wires that can be used stably up to a higher temperature region by changing the material of the insulation coating and the conductive wires can be called heat-resistant electric wires. As an insulating coating for such a heat-resistant electric wire, a glass fiber braid knitted with glass fiber is often used in order to maintain heat resistance. In particular, it is suitably used for a high-temperature sensor that measures the combustion temperature of exhaust gas from combustion equipment.
However, an insulating coating made of a glass fiber braid tends to break apart when the terminal is untied, and thus requires terminal processing to make it difficult to unravel.
[0003]
FIGS. 7A and 7B show a heat-resistant electric wire that has been subjected to terminal treatment by a conventional method.
In FIG. 7A, a heat-resistant electric wire 100 includes a conductive wire 101 made of nickel and a glass fiber braided insulation coating 102 formed by knitting quartz glass fibers. In this heat-resistant electric wire 100, the end portion of the insulating coating 102 is bound using the glass yarn 103, and the terminal treatment is performed by cutting and removing the insulating coating 102 at the tip from the binding portion. Here, as a method of binding the glass line 103, a method similar to the procedure for binding the fishing line to the fishing hook is used.
On the other hand, in the heat-resistant electric wire 100 shown in FIG. 7 (B), an adhesive polyimide-based heat-resistant varnish is impregnated in a portion to be a terminal of the insulating coating 102 to form a fixing portion 104 of glass fiber. The terminal treatment is performed by cutting and removing the insulating coating 102 at the tip including a part of the fixing portion 104.
That is, glass, which is the material of the insulating coating 102, is more stable chemically and thermally than the conductive wire 101. Therefore, when a chemical or heat is applied directly to the conductive wire 101, the conductive wire 101 is ahead of the insulating coating 102. May invade. For this reason, conventionally, as described above, a processing method for fixing or fixing the insulating coating 102 has been used.
[0004]
[Problems to be solved by the invention]
However, in the terminal processing method for binding with the glass yarn 103, the workability is poor because the glass yarn 103 to be bound is easily cut. In particular, when the diameter of the insulating coating 102 is reduced to, for example, 2 mm or less, workability is further deteriorated. Further, since the glass yarn 103 is fixed only by the frictional force, there is a concern that the binding force is lost if it is displaced.
Further, in the terminal treatment method in which the polyimide-based heat-resistant varnish is fixed, the polyimide-based varnish is decomposed at a temperature of 500 ° C. or higher, and the insulating property of the insulating coating 102 is deteriorated. In addition, since the adhesive strength is lost even below the decomposition temperature, the practical use upper limit temperature is considered to be in the range of 300 ° C., and use in a temperature range beyond that is difficult.
[0005]
The objective of this invention is providing the heat-resistant electric wire which can perform a terminal process rapidly and reliably, and its terminal processing method.
[0006]
[Means for Solving the Problems]
The end treatment method for a heat-resistant electric wire according to the present invention is a method for end treatment of a heat-resistant electric wire configured by covering a metal conductor with a glass fiber insulation coating, and heating the middle of the insulation coating in the longitudinal direction to form the glass After the fibers are heat-sealed to each other, a wire stripper blade is applied to the substantially center position of the heat-sealed portion to cut the insulating coating so that the conductor is not cut, and the blade is used to cut the conductor more than the cut portion. The insulating coating on the side to be exposed is removed.
In the present invention, the terminal treatment is performed by thermally fusing the glass fibers. However, the work is quickly performed by heating the necessary portion of the insulating coating for a short time such as several seconds. Further, there is no problem that the terminal can be unwound by thermally fusing the glass fiber.
[0007]
Moreover, the heat-resistant electric wire of this invention was processed by the above terminal processing method, It is characterized by the above-mentioned.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
However, for the sake of convenience, hereinafter, the same reference numerals are given to the heat-resistant electric wires before and after the terminal processing.
FIG. 1 is a side view showing a heat-resistant electric wire 10 according to the present embodiment subjected to terminal processing. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a side view showing the heat-resistant electric wire 10 after the terminal treatment.
In FIG. 1 and FIG. 2, the heat-resistant electric wire 10 includes, for example, a conductive wire 11 made of nickel, a glass fiber braid 13 made by knitting glass fiber 12 made of quartz glass, and a conductive wire 11 between the conductive wire 11 and the insulating coating 15. The glass fiber tape 14 wound so as to be entangled with each other, and the glass fiber braid 13 and the glass fiber tape 14 constitute an insulating coating 15.
In addition, although illustration is abbreviate | omitted, the glass fiber tape 14 is made by bundling a predetermined amount of fibers similar to the glass fiber 12.
[0010]
In FIG. 3, the end part of the insulation coating 15 of the heat-resistant electric wire 10 is a fusion part 16 formed by heating. The fused portion 16 is obtained by integrally fusing the glass fibers 12 of the glass fiber braid 13 and the glass fibers of the glass fiber tape 14, and has a gloss appearance in comparison with the braided portion of the other insulating coating 15. In addition, it is mechanically cured.
From the fused portion 16, a cut end portion of the conducting wire 11 is exposed, and this exposed portion is connected to a device such as a high-temperature pressure sensor.
[0011]
Next, a terminal processing method for the heat-resistant electric wire 10 will be described with reference to FIG.
First, in FIG. 4 (A), the heat-resistant electric wire 10 is cut out from a reel or the like for a required length, and an intermediate position in the longitudinal direction of the extracted heat-resistant electric wire 10, that is, a position close to the tip of the heat-resistant electric wire 10 is insulated. In order to make the terminal, the insulating coating 15 is heated by the hydrogen flame 20 for a short time, for example, for several seconds, to form the fused portion 16. At this time, the temperature of the hydrogen flame 20 is adjusted to a temperature near the softening point of the glass fiber 12 or the like forming the insulating coating 15.
Thereafter, as shown in FIG. 4B, the right side portion in FIG. 4 is sandwiched by the sandwiching side 21 </ b> A constituting the wire stripper with respect to the fusion portion 16, and the blade 21 </ b> B is located at a substantially central position of the fusion portion 16. The insulation coating 15 on the tip side of the fusion part 16 is cut and removed by the blade 21B.
As described above, the end-treated heat-resistant electric wire 10 shown in FIG. 3 is obtained.
[0012]
According to this embodiment, there are the following effects.
That is, the end treatment of the heat-resistant electric wire 10 is performed by partially heat-sealing the insulating coating 15, and in the fusion, it is only necessary to heat the position desired as the terminal for a short time such as several seconds, Work time can be significantly reduced and terminal processing can be performed quickly.
[0013]
For this reason, it becomes possible to perform the terminal process of many heat-resistant electric wires 10 continuously, and can improve work efficiency markedly compared with the terminal process bundled with a glass thread.
In particular, when the diameter of the insulating coating 15 is as small as 2 mm or less, for example, the heating time becomes shorter, so that workability is further improved.
[0014]
Further, since the terminal processing is performed by fusing the glass fibers 12 and the like, the conventional binding portion is not displaced and the binding force is not lost, and the reliability can be improved.
And since polymer materials, such as a varnish, are not used, the high heat resistance of each member which comprises the heat-resistant electric wire 10 can be utilized effectively, and the practical use upper limit temperature of the heat-resistant electric wire 10 can be expanded.
[0015]
FIG. 5 is a process chart for explaining the second embodiment, and another method for obtaining the heat-resistant electric wire 10 will be explained based on this figure. The contents of the present embodiment are not included in the scope of the right of the present invention, but will be described for reference in understanding the present invention.
In the present embodiment, as shown in FIG. 5 (A), in the heat-resistant electric wire 10 that has not been subjected to the terminal treatment, the portion on the tip side from the position to be used as the terminal of the insulating coating 15 is cut and removed in advance with the blade 21B. Thereafter, as shown in FIG. 5B, the cut portion 37 of the insulating coating 15 is heated by the hydrogen flame 20 to form the fused portion 16.
[0016]
According to this embodiment, it is possible to obtain substantially the same effect as that of the above-described embodiment.
By the way, when the heating of the cutting part 37 is performed not only so that the glass fibers 12 are fused to each other but also to the extent that the glass fibers 12 are also fused to the conductive wire 11, the excess insulation coating 15 is also fixed to the conductive wire 11 and removed. May be difficult to do. However, in the present embodiment, since the excess insulating coating 15 is removed before being heated, the glass fiber 12 can be sufficiently heated. Therefore, the required insulating coating 15 is securely fixed to the conducting wire 11, and the displacement of the insulating coating 15 with respect to the conducting wire 11 can be more effectively prevented.
[0017]
The present invention is not limited to the above-described embodiments, and includes other configurations that can achieve the object of the present invention, and includes the following modifications and the like.
For example, in the above-described embodiments, the conductive wire 11 is made of nickel. However, other materials may be stainless steel, silver, or the like, and may be a material generally used as a conductive wire.
[0018]
In each of the above embodiments, the glass fiber braid 13 and the glass fiber 12 forming the glass fiber tape 14 are made of quartz glass. However, the glass fiber used in the present invention is made of quartz. In addition to glass, for example, non-alkali glass may be used.
[0019]
And as these glass fiber braiding and glass fiber tape, it is not limited to what is formed only from glass fiber. In particular, the glass fiber braid may be manufactured by impregnating a small amount of polyimide resin so that the glass fiber is not easily broken and the entire braid is not easily unwound.
In short, glass fiber may be a main material, and the present invention can be applied even if a material other than glass is included.
Further, the glass fiber tape is not limited to a bundle of a predetermined amount of glass fiber, and may be, for example, a glass thread wound spirally around a conductor.
[0020]
Furthermore, in each said embodiment, although the insulation coating 15 was comprised from the glass fiber braid 13 and the glass fiber tape 14, it is not limited to this, For example, among glass fiber braids and glass fiber tapes Even in the case where the insulating coating is constituted by only one of the above, it is included in the present invention.
[0021]
Further, in each of the above embodiments, the hydrogen flame 20 is used as a heating means. However, the hydrogen flame 20 is not limited to the hydrogen flame 20, and is not limited to an electric heater or an acetylene / oxygen flame using a hydrocarbon gas, butane gas. In short, any heating means capable of heating, melting, and cooling a part of the insulating coating 15 for a predetermined time may be used.
However, if a hydrogen flame is used as in the present embodiment, the gas component does not contain carbon atoms, and soot due to unburned gas does not occur during heating. Accordingly, it is possible to eliminate the anxiety that the soot adheres to the insulating coating 15 and causes deterioration of the insulating property. The hydrogen flame also has an advantage that the temperature control of the combustion flame is easy.
Further, as a means for heating for a predetermined time, an apparatus that can be automatically separated from the flame after a predetermined time may be used.
[0022]
Furthermore, in each of the above-described embodiments, the wire stripper having the same configuration is used as a method for cutting and removing the insulating coating 15. However, as the wire stripper used in the second embodiment, the insulating coating 15 is used. A function of clamping the cut end portion may be provided in order to prevent the cut end portion from being unraveled even when the predetermined portion is cut. Alternatively, in addition to the wire stripper, a dedicated jig that preliminarily holds a portion to be a cut end may be provided, and the jig may be removed after heat fusion is performed.
However, it is not necessary to use a wire stripper for cutting the insulating coating 15, and other methods may be used as long as the insulating coating 15 is cut without damaging the conductive wire 11.
[0023]
In each of the above embodiments, the insulating coating 15 on the distal end side of the insulated wire 10 is removed after being cut, but such an extra insulating coating may be simply shifted to the distal end side. .
In such a case, it is desirable that both ends of the shifted insulation coating are also heat-sealed, and this can prevent the insulation coating from being unwound. Moreover, such an electric wire may be used by cutting the exposed conductor or without cutting it.
[0024]
Further, in each of the above embodiments, the conductive wire 11 is exposed from the end portion of the fused portion 16, but the conductive wire 11 is particularly used when the tip of the heat-resistant electric wire is left unconnected to a device or the like for a long period of time. When it is not necessary to expose the wire, it may be heat-sealed so that the insulation coating at the tip of the heat-resistant electric wire is not broken.
In other words, in the present invention, whether or not the conductive wire is exposed after the insulation coating is cut or the like may be appropriately determined in the implementation. In short, it is only necessary that the end portion of the insulating coating is heat-sealed.
[0025]
By the way, in the said 1st Embodiment, since a part of hardened fusion | fusion part 16 is crushed by contact | abutting of the blade 21B, glass powder arises in that case and this glass powder is the circumference | surroundings of the cutting part 17. It may scatter and adhere. This in itself does not hinder the function as the heat-resistant electric wire 10, but the adhered glass powder may become a dust generating material from the heat-resistant electric wire 10 by detaching from the adhesion portion due to vibration or the like.
Therefore, when glass powder is generated, as shown in FIG. 6 as the next operation of FIG. 4 (B), the cut portion 17 is reheated with a hydrogen flame 20 for several seconds, for example, and the adhered glass powder 18 is removed. It may be refused. By doing so, the broken and adhered glass powder 18 is re-fused, so that dust generation from the heat-resistant electric wire 10 can be reliably prevented.
If a dust absorber or the like is used at the time of cutting the fusion part 16, it is possible to effectively prevent the glass powder from being scattered at the time of cutting, and the adhesion of the glass powder to the heat-resistant electric wire 10 can be suppressed.
In addition, according to the second embodiment, after the cutting portion 37 is formed in advance, the cured portion 16 is cut in order to thermally bond the cutting portion 37 to the first embodiment. Unlikely, there is no worry that the glass powder 18 is generated at the time of cutting.
[0026]
Furthermore, this invention can be used as an electric wire of not only what is used for the temperature sensor for high temperature but other various apparatuses.
[0027]
【Example】
[First embodiment]
Here, the specific conditions of the terminal processing method were as follows, and the heat-resistant electric wire 10 was manufactured based on the first embodiment.
(1) Conductor 11 ... φ300μm nickel, melting point: 1455 ° C (material data)
(2) Insulation coating 15 ... softening point temperature: 1300-1600 ° C (material data)
・ Glass fiber braid 13 (quartz glass fiber 12)
・ Glass fiber tape 14 (quartz glass fiber)
(3) Temperature of the hydrogen flame: around 1500 ° C. (measured using a 0.1 mm platinum / platinum 13% rhodium bare wire thermocouple)
(4) Heating time: 2 seconds According to this example, it was confirmed that the terminal treatment can be performed quickly and reliably, and the heat-resistant electric wire 10 that can withstand use at high temperatures can be produced.
[0028]
By the way, since the melting point of the conducting wire 11 is 1455 ° C., the softening temperature of the insulating coating 15 is as wide as 1300 to 1600 ° C. Therefore, when the insulating coating 15 having a softening temperature higher than 1455 ° C. is used, the heating process is performed. In this case, the conductive wire 11 may be melted before the insulating coating 15. However, in the present embodiment, the insulating coating 15 becomes a softening point before the conductive wire 11 reaches the melting point for the following reasons (a) and (b). It has been found that the adjacent glass fibers 12 are always fused together without melting first. Thus, it was confirmed that the practical heat-resistant electric wire 10 can be reliably manufactured even when the insulating coating 15 having a high softening temperature is used.
(A) Since the glass fiber 12 or the like forming the insulating coating 15 has a thickness of several μm, the surface area {(surface area) / (volume)} per unit volume is several tens compared to the conductor 11 having a diameter of 300 μm. It is twice as large, and the temperature quickly rises due to the heat received from the hydrogen flame 20.
(B) Since the conductive wire 11 is protected by the insulating coating 15 and heat from the hydrogen flame 20 is difficult to be transmitted, the transmitted heat flows to the non-heated region due to the good thermal conductivity of the metal. The temperature of the conducting wire 11 does not reach the melting point.
[0029]
[Second Embodiment]
Next, as a second example, after a trace amount of polyimide resin was impregnated into a heat-resistant electric wire that had not been subjected to terminal treatment, terminal treatment was performed under the same conditions as in the first example.
As a result, it was confirmed that it was possible to produce a heat-resistant electric wire in which the glass fiber was difficult to cut in the finished product and the entire glass braid was not easily unwound.
In addition, when such an insulation coating is heated, a black region carbonized with polyimide resin is formed at the boundary between the heated portion and the non-heated portion of the insulation coating. As a result, a value of 100 MΩ or more / 500 VDC was obtained, and it was confirmed that it was practical.
[0030]
【The invention's effect】
As described above, according to the present invention, the end treatment of the heat-resistant electric wire is performed by heat-sealing the insulating coating made of glass fiber, so that the processing operation can be performed quickly and reliably. There is.
[Brief description of the drawings]
FIG. 1 is a side view showing a heat-resistant electric wire according to a first embodiment of the present invention that is subjected to terminal processing.
FIG. 2 is a cross-sectional view taken along line II-II in FIG.
FIG. 3 is a side view showing the heat-resistant electric wire subjected to terminal treatment.
FIG. 4 is a process diagram for explaining a terminal processing method in the embodiment.
FIG. 5 is a process chart for explaining a second embodiment of the present invention.
FIG. 6 is a side view showing a modification of the present invention.
FIG. 7 is a side view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Heat-resistant electric wire 11 Conductor 12 Glass fiber 15 Insulation coating 17 Cutting part

Claims (2)

A heat-resistant electric wire terminal treatment method configured by covering a metal conductive wire with a glass fiber insulating coating, and heating the glass fiber in the longitudinal direction of the insulating coating to thermally bond the glass fibers to each other. A wire stripper blade is applied to a substantially central position of the fused part to cut the insulating coating so that the conductive wire is not cut, and this blade removes the insulating coating on the side where the conductive wire is to be exposed from the cut portion. A method for treating the end of a heat-resistant electric wire. A heat-resistant electric wire processed by the terminal processing method according to claim 1.

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