JP4046794B2 - Cord temperature fuse - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cord-like thermal fuse that reliably detects an abnormal temperature of a thermal device or the like, and more particularly to one that greatly improves strip workability during terminal processing.
[0002]
[Prior art]
The applicant has previously disclosed, for example, a cord-like temperature fuse capable of reliably detecting abnormal temperatures in various thermal equipment such as gas water heaters and petroleum fan heaters as disclosed in JP-A-5-128950 and JP-A-6-6. No. 181028, Japanese Patent Application Laid-Open No. 7-176251, Japanese Patent Application No. 7-306750, and the like. An example of the configuration is shown in FIGS.
[0003]
In the figure, there is a tensile body 31 formed by subjecting a glass cord to a silicone varnish treatment, and an elastic material 33 having a plurality of projections on the surface is extrusion coated on the outer periphery of the tensile body 31. The tensile body 31 and the elastic material 33 constitute an elastic core 35, and two conductor thin wires 37 integrated with a flux containing a specific anti-aging agent are drawn on the outer periphery of the elastic core 35. They are aligned and wound sideways with the elastic material 33 sufficiently invaded. A center member 39 is constituted by the conductor thin wire 37 and the elastic core 35, and the center member 39 is sufficiently wound into the conductor thin wire 37 so that the cross-sectional shape thereof becomes substantially circular. ing.
[0004]
A space layer 41 is formed on the outer periphery of the central member 39. The space layer 41 is formed by braiding a fiber bundle obtained by twisting alkali-free glass filaments to a desired braid density using a stringing machine. A cord-shaped thermal fuse is formed by providing an insulating coating 43 on the outer periphery of the space layer 41. The insulating coating 43 is formed by, for example, extruding and coating fluororubber with a desired thickness while cooling with water, and then performing crosslinking by irradiation with an electron beam.
[0005]
This type of cord-like temperature fuse can detect the abnormal temperature immediately by melting even if a part of the conductor thin wire is exposed to an abnormally high temperature, and can also detect the abnormal temperature reliably. It is suitable for use as a safety device that detects abnormal temperatures of various types of thermal equipment, such as gas water heaters and oil fan heaters, because it does not malfunction due to reconnection of thin conductor wires. Can do.
[0006]
[Problems to be solved by the invention]
However, in this type of cord-shaped thermal fuse, the space layer provided for the purpose of preventing the recombination of the thin conductor wires is made of a braided or laterally wound fiber material such as glass fiber or alumina fiber. Therefore, when stripping the insulation coating at the end processing, those fiber materials remain on the center material without being cut, and further removal work is required, so that the strip workability is greatly reduced. There was a problem that it was. When removing the remaining fiber material, extremely careful work is required so as not to damage the thin conductor wire. This work takes a long time and reduces the strip workability. It ended up.
[0007]
Also in the manufacturing process, there is a problem that the braiding process and the horizontal winding process that are required when forming the space layer increase the number of manufacturing processes and lower the productivity.
[0008]
The present invention has been made based on such points, and an object of the present invention is to provide a cord-shaped thermal fuse that greatly improves the strip workability during terminal processing at a low cost.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the cord-shaped thermal fuse according to the present invention has a tape-shaped molded body on the outer periphery of a fuse core formed by winding a conductor thin wire that melts at a predetermined temperature on an elastic core continuous in the longitudinal direction. In addition, the tape-shaped molded body is capable of preventing the flow of the melted conductor thin wire, and the surface has a fine uneven shape. Is. At this time, it is conceivable that the tape-shaped molded body is composed of an aggregate of fibers. Moreover, it is possible that the tape-shaped molded object is equipped with the adhesive layer in the surface on the side which contacts an insulation coating. Furthermore, it is conceivable that the tape-shaped molded body is provided with flocking on the surface in contact with the fuse core.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The elastic core is a structure in which an elastic material is coated around a central tensile body. Examples of strength members include inorganic fibers such as glass fibers, alumina fibers, and alumina / silica fibers, organic fibers such as polyester fibers, polyamide fibers, polyolefin fibers, and fluorine fibers, and metal fibers such as stainless steel fibers. Can be used. As the elastic material, any conventionally known general elastomer material such as silicone rubber or fluororubber can be used. At this time, as proposed by the applicant in Japanese Patent Laid-Open No. 7-176251, if an elastomer material containing a predetermined amount of a gas generating substance is used, the sensitivity of the cord-like thermal fuse obtained by the present invention is further increased. You can also.
[0011]
The cross-sectional shape of the elastic core is not particularly limited, but preferably a cross-sectional shape having a plurality of convex portions in the radial direction. This includes not only regular polygons but also star-like shapes. In addition, the star shape and the polygon are generally shapes having clear corners, but may be shapes having rounded corners. These are preferable because a conductor thin wire, which will be described later, easily bites into the elastic core as compared with the case of a circular cross section, and breaks more quickly when the conductor thin wire is melted. When the cross-sectional shape is a polygon, it is preferably a hexagon or less from the viewpoint of easy penetration of the conductor thin wire.
[0012]
A thin conductor wire is preferably wound on the elastic core at a pitch of 1.5 times or more, more preferably 2 to 15 times the wire diameter, to form a fuse core. As the conductor thin wire, a metal thin wire selected from the group consisting of a low melting point alloy and solder can be used. Examples of the low melting point alloy and the solder are those having a melting point of 300 ° C. or less, as exemplified in “Basic Manual for Chemistry, Revised 3rd Edition, published by Maruzen Co., Ltd.” on page I-509. The wire diameter of the conductor thin wire is preferably about 0.04 mm to 0.8 mm which can be wound around an elastic core by a general horizontal winding machine. As the conductor thin wire, a flux-treated one as proposed by the applicant in Japanese Patent Application Laid-Open No. 6-181028 and Japanese Patent Application No. 7-306750 may be used. The sensitivity of the cord-like thermal fuse obtained by the present invention can be further increased.
[0013]
By forming a tape-shaped molded body on the fuse core having the above structure, recombination of the conductor thin wires after the abnormal temperature detection (after melting disconnection) is prevented, or the conductor thin wires are removed from the heat during the formation of the insulation coating. It functions as a space layer for protection. Examples of the tape-shaped molded body include paper tape, polyester polymer, polyamide polymer, polyolefin polymer, fluorine polymer, or a film made of an organic polymer material in which these are mixed, or glass fiber or alumina fiber. And an aggregate of fibers made of inorganic fibers such as alumina / silica fibers, organic fibers such as polyester fibers, polyamide fibers, polyolefin fibers, and fluorine fibers. Examples of the fiber assembly include a woven fabric, a non-woven fabric, and a warp yarn assembly.
[0014]
In the present invention, any of the above tape-shaped molded products may be used, but preferably a paper tape or an aggregate of fibers, more preferably a nonwoven fabric among the aggregates of fibers. Paper tape or nonwoven fabric is conventionally because of its sufficiently low tear strength than such fibers braid which has been used as a spatial layer, when stripped of insulation, would be simultaneously cut and removed and the insulating coating, the terminal Strip workability during processing is greatly improved. Furthermore, since these surfaces have a fine irregular shape, the effect of preventing the flow of the melted conductor thin wire is great, and the recombination of the conductor thin wire after the abnormal temperature detection (after the melt disconnection) is more reliably performed. Can be prevented.
[0015]
In the present invention, a tape-shaped molded body having an adhesive layer on the surface in contact with the insulating coating may be used. Examples of the adhesive include urethane adhesives, vinyl acetate adhesives, acrylic adhesives, isocyanate adhesives, hot melt adhesives, and the like. These adhesives may be formed in advance on the tape-shaped molded body by a method such as impregnation or coating, or may be formed on the tape-shaped molded body when an insulating coating is applied. By using the tape-shaped molded body provided with the adhesive layer, the insulating coating and the tape-shaped molded body are in good contact with each other, so that the tape-shaped molded body can be cut and removed more reliably. In particular, it is preferable to use a non-woven fabric provided with an adhesive layer, because the adhesiveness of the adhesive and the anchor effect of the non-woven fabric itself can be more firmly adhered to the insulating coating.
[0016]
Moreover, you may use the thing provided with the flock on the surface of the side which contacts a fuse core as a tape-shaped molded object. By using a tape-shaped molded body with flocking, the frictional resistance with the fuse core can be reduced, so strip work can be performed easily and the conductor thin wires that make up the fuse core are damaged. There is no need to worry. Furthermore, since a sufficient space can be maintained between the fuse core, the flow of the melted conductor thin wire can be more reliably prevented.
[0017]
The tape-shaped molded body described above is formed on the fuse core by being vertically attached or horizontally wound. Either method may be adopted, but the longitudinal addition molding is preferable because the insulating coating can be formed simultaneously with the formation of the tape-shaped molded body, and thus the productivity is greatly improved.
[0018]
Since various methods are conventionally known, the insulating coating is formed by appropriately adopting a method capable of realizing a processing temperature lower than the temperature at which the conductor thin wire melts. For example, a method in which a composition mainly composed of a thermoplastic polymer such as an ethylene-based copolymer that can be extruded at a relatively low temperature is crosslinked by a crosslinking method that can be performed at a low temperature such as electron beam crosslinking or silane crosslinking. A method of forming by using a silicone rubber that can be extruded and crosslinked at a relatively low temperature, a method of applying an insulating varnish that is braided with various fiber materials and then dried at room temperature, and the like are conceivable. Any of these methods may be employed, but preferably extrusion is employed. If the insulating coating is formed by extrusion, a tape-shaped molded body can be formed at the same time, so that productivity is improved.
[0019]
The method of using the cord-shaped thermal fuse of the present invention thus obtained is arbitrary in various applications and is not particularly limited. For example, a cord-shaped thermal fuse may be used as it is disposed around a thermal device or the like, or the applicant may use JP-A-5-128950, JP-A-6-181028, JP-A-7-176251, As proposed in Japanese Patent Application No. 7-306750, etc., a surface processed product may be disposed and used in a thermal device or the like. As a processing method when the cord-shaped thermal fuse is electrically connected to an external circuit, a conventionally known method such as the method proposed by the applicant in Japanese Patent Laid-Open No. 7-176359 may be employed as it is. .
[0020]
【Example】
Examples of the present invention will be described below together with comparative examples.
[0021]
Example 1
The cord-shaped thermal fuse shown in FIGS. 1 and 2 was manufactured. The elastic core 5 was manufactured by extrusion-coating silicone rubber as the elastic material 3 around the tensile body 1 obtained by applying a silicone varnish treatment to a glass cord having an outer diameter of about 1.8 mm, and simultaneously performing hot air vulcanization. Next, two conductor thin wires 7 made of solder wires having a melting point of 183 ° C. and an outer diameter of 0.6 mmφ, in which a flux containing an anti-aging agent is sealed in the central portion, are arranged at the corners of the elastic core 5 and pitched. A fuse core 9 was obtained by lateral winding at 8.5 mm.
[0022]
The fuse core 9 was deformed into a substantially circular cross-sectional shape due to the biting of the conductor thin wire 7. Thereafter, on the circumference of the fuse core 9, a tape-like molded body 11 made of a polyethylene terephthalate nonwoven fabric having a width of 12 mm and a thickness of 30 μm and provided with a vinyl acetate-based adhesive layer (not shown) on one side is arranged vertically with the adhesive layer facing outward. At the same time, an insulating coating 13 was formed by extrusion coating a composition mainly composed of polyethylene with an inner thickness of 0.5 mm. Finally, crosslinking was performed by irradiating with an electron beam under an irradiation dose of 650 kGy to obtain a cord-shaped thermal fuse having a finished outer diameter of 4.2 mm.
[0023]
Example 2
A tape-shaped molded body made of glass chopped strand nonwoven fabric having a width of 12 mm and a thickness of 100 μm and provided with a vinyl acetate adhesive layer not shown on one side was formed by longitudinal addition molding on the circumference of the fuse core. A cord-shaped thermal fuse having a finished outer diameter of 4.2 mm was obtained using the same material and the same construction method as in Example 1.
[0024]
Comparative example A fiber bundle made by twisting a non-alkali glass filament having a single fiber diameter of about 9 μm on the circumference of the fuse core to be about 70th was knitted at a braid density of 17 stitches / 25 mm using a 16-placing machine. A cord-shaped thermal fuse having a finished outer diameter of 4.2 mm was obtained by the same material and the same construction method as in Example 1 except that braiding and subsequent insulation coating were formed.
[0025]
Here, in order to evaluate the end workability (strip workability) of the above three types of cord-shaped thermal fuses, about 6 mm of the insulation coating of the end portion was stripped with a wire stripper, and the surface state of the fuse core was confirmed.
[0026]
As a result, both of the cord-shaped thermal fuses according to the present embodiment can remove the tape-shaped molded body at the same time when stripping the insulation coating, and there is no abnormality in the conductor thin wire constituting the fuse core. Was also not recognized. In contrast, the conventional cord-type thermal fuse prepared as a comparative example was able to strip the insulation coating, but the braided material remained on the fuse core without being cut, and further removal work is required. It has become.
[0027]
In this example, the sensitivity and recombination of the above three types of cord-shaped thermal fuses were also evaluated. Regarding sensitivity, hot air of 250 ° C. was applied to the cord-shaped thermal fuse, and the time until the conductor thin wire was disconnected was measured. Regarding recombination, a light bulb was connected in series to a cord-shaped thermal fuse in which a conductor thin wire was disconnected, and this was shaken up and down and left and right with hot air of 250 ° C. to observe the presence or absence of chattering of the light bulb.
[0028]
As a result, in this example and the comparative example, the conductor fine wire was disconnected in about 45 seconds, and good sensitivity was shown. In addition, no chattering was observed.
[0029]
As described above, it has been demonstrated that the cord-like thermal fuse according to the present embodiment can greatly improve the strip workability at the time of terminal processing while maintaining the same sensitivity and safety as the conventional one.
[0030]
【The invention's effect】
As described above in detail, according to the present invention, by forming the tape-shaped molded body between the fuse core and the insulation coating, the strip work at the end processing becomes extremely easy, and the workability is greatly improved. . In addition, in the manufacturing process, an insulating coating can be simultaneously formed while longitudinally forming a tape-shaped molded body on the periphery of the fuse core, so that mass production with excellent productivity is possible. Accordingly, it is possible to provide a cord-like thermal fuse that can detect an abnormal temperature reliably by exposing a part of the conductor thin wire immediately to an abnormally high temperature so that an abnormal temperature can be detected at low cost.
[Brief description of the drawings]
FIG. 1 is a partially cutaway side view of a cord-shaped thermal fuse showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an elastic core constituting a cord-like thermal fuse in a diagram showing an embodiment of the present invention.
FIG. 3 is a partially cutaway side view of a cord-shaped thermal fuse showing a conventional example.
FIG. 4 is a cross-sectional view of an elastic core constituting a cord-shaped thermal fuse in a diagram showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Resistant body 3 ... Elastic material 5 ... Elastic core 7 ... Conductor thin wire 9 ... Fuse core 11 ... Tape-shaped molded object 13 ... Insulation coating

Claims (4)

A tape-shaped molded body is formed on the outer periphery of a fuse core formed by winding a conductor thin wire that melts at a predetermined temperature on an elastic core continuous in the longitudinal direction so as to be in contact with the fuse core , and the tape-shaped molded body A cord-shaped thermal fuse in which an insulating coating is formed on the outer periphery of the tape, wherein the tape-shaped molded body is capable of preventing the flow of the melted conductor thin wire, and is insulated when the insulating coating is stripped. A cord-like thermal fuse characterized by having a tear strength that can be cut and removed at the same time and having a fine uneven surface.   2. The cord-shaped thermal fuse according to claim 1, wherein the tape-shaped molded body is made of an aggregate of fibers.   3. The cord-shaped thermal fuse according to claim 1, wherein the tape-shaped molded body includes an adhesive layer on a surface on a side in contact with the insulating coating.   The cord-shaped thermal fuse according to claim 1, 2, or 3, wherein the tape-shaped molded body has a flocked surface on a surface in contact with the fuse core.

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