JPS61285689A - Heatsensitive wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat-sensitive wire having a heat generation function and a temperature detection function, which is used in planar heating devices such as electric blankets and electric carpets.

Conventional technology The cord-shaped heat-sensitive wires conventionally used in electric blankets and electric carpets include two wires, a cord-shaped heating wire shown in Figure 4 and a cord-shaped detection wire shown in Figure 5, which are incorporated into a planar heating device. is used.

In the structure of the cord-shaped heating wire, 8 is a core yarn made of polyester fiber, heat-resistant polyamide, etc.; 9 is a heating wire made of copper, copper alloy, etc., spirally wound around the outer periphery of the core yarn 8; 10
is a crystalline resin that melts and softens at 150 to 190°C and has negative temperature characteristics when the temperature becomes abnormal, such as nylon 1.
1. A fuse layer 11 is a fuse layer 10 formed by extruding and covering the outer periphery of the core thread 8 and the heating wire 9 with nylon 12 or the like.
The leakage current flowing in the fuse layer 10 between the wire 9 and the heating wire 9 or the short circuit current flowing due to melting of the fuse layer 10 is detected and the safety circuit of the control circuit is activated to generate heat. 12 is a fuse layer 10 which has the function of interrupting the heating current flowing through the line 9;
and an insulating jacket made of polyvinyl chloride formed by extrusion-molding the outer periphery of the abnormality detection wire 11.

Further, as shown in FIG. 5, the cord-like detection wire is a core thread 16 made of polyester, heat-resistant polyamide, or the like.

14 is an internal detection wire made of copper, copper alloy, etc. wrapped around the outer circumference of the core thread 13; 15 is a composition having a negative temperature coefficient, such as polyvinyl chloride resin added with 1 to 5% by weight of quaternary ammonium salt; 16 is an external sensing wire made of copper, copper alloy, etc. wrapped around the outer periphery of the heat-sensitive layer 15; 17 is an external sensing wire made of copper, copper alloy, etc.; This is an insulating jacket formed by extrusion molding and covering the outer periphery of the heat sensitive layer 14 and the external sensing wire 16 with polyvinyl chloride.

The corded heating wire and the corded detection wire are meanderingly arranged and fixed in a predetermined pattern on a planar heating device such as an electric blanket or an electric carpet, and are combined with a control circuit to provide a comfortable heating temperature. It makes it seem possible.

That is, in the case of operation at a heating temperature of 30 to 60°C in normal use, the impedance of the heat sensitive layer 15 is determined by the internal detection line 14.
and the external detection line 16 to control the heating current flowing through the heating wire 9 of the cord-shaped heating wire.

Also, in the case of an abnormal condition where the temperature rises above the heating temperature due to a failure of a control circuit element or external heating.

The abnormality detection wire 11 detects the leakage current flowing through the heating layer 10 and operates the safety circuit built into the control circuit to cut off the heating current flowing through the heating wire 9 to prevent burns to the two people or burnout of the sheet heating device. prevent it from happening.

In this way, the fuse layer 10 and the heat sensitive layer 15 are divided into two types, a cord-shaped heating line and a cord-shaped detection line, and perform different roles and functions.

Problems to be Solved by the Invention However, the conventional planar heating device using a cord-shaped heating wire and a cord-shaped detection wire has the following problems, and there is a need to solve them.

Mountain Cord-shaped heating wires and cord-shaped detection wires are arranged in different meandering arrangement patterns and fixed, which not only makes workability worse, but also makes the planar heating device uneven if they are arranged overlapping each other. Otherwise, the cord may become damaged and cause a malfunction.

(2) Surface heating devices have hard cord-like materials built into the fibrous insulation material, such as blanket fabric or needle punch felt, so if multiple cord-like materials are used, foldability may be poor. , there is a strange feeling when using it.

(3) Contact reliability is ensured because the inner detection wire 14 in FIG. The temperature-dependent performance of the impedance cannot be fully exploited, and the temperature detection performance deteriorates.

(4) The thickness of the heat-sensitive layer 15 shown in Fig. 5 cannot be reduced to 0.2 mm or less due to extrusion molding technology constraints and mechanical strength. It is necessary to add a higher amount of quaternary ammonium salt than is originally required, and as a result, the added quaternary ammonium salt causes bleeding and migration phenomena, causing impedance to change over time during use. temperature detection sensitivity decreases.

(5) Materials and manufacturing man-hours for the corded heating wire and the corded sensing wire are required, making it impossible to obtain a low-cost planar heating device.

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems of the conventional art, and includes α005 to α00. A pair of detection wires, each coated with a heat-sensitive layer having a thickness of 0.5 mm and a negative temperature coefficient and a melting softening point of 140 to 180 degrees Celsius, was wrapped in a spiral in parallel in parallel to each other. 1
A fuse layer is formed by extrusion molding a crystalline resin with a melting point of 50 to 190°C, and a heating wire is spirally wound around the outer circumference of the fuse layer, and then the whole is covered with an insulating jacket made of polyvinyl chloride. It has a covered structure.

A pair of detection wires coated with an active heat-sensitive layer are spirally wound in parallel around the outer periphery of a conductive core thread, and then the heating wire of the heating layer 1 and the insulating jacket are each coated with gold around the outer periphery of the heat-sensitive wire. By doing so, it has the functions described below and has great industrial utility value.

(1) A single cord-shaped heat-sensitive wire can detect normal temperature and abnormal temperature, and the workability of incorporating it into a one-sided heating device can be improved.

(2) Structurally, it has better flexibility, which improves the foldability of the planar heating device and reduces discomfort when using it.

(3) Since the heat-sensitive layer is uniformly coated on the surface of the detection wire and wound around the conductive core yarn, contact reliability with the heat-sensitive layer is ensured, and temperature detection sensitivity is high.

(4) Because the heat-sensitive layer is a thin film with a thickness of 0.005 to 0.051 m.

It has excellent temperature detection sensitivity without adding additives to improve therminuta more than necessary, and can suppress changes in impedance over time.

(5) A low-cost planar heating device can be obtained because the heat-sensitive wire uses less material and the number of manufacturing steps is less, resulting in high efficiency.

Example An embodiment of the present invention will be described below in detail with reference to the drawings.

Figure 1 shows the structure of a heat-sensitive wire according to an embodiment of the present invention, in which 1 is made of carbon fiber, polyester, heat-resistant polyamide,
2 is a conductive core yarn made of conductive paint or nickel plating applied to the surface of heat-resistant fibers such as glass, and 0.00.
A thermosensitive layer made of, for example, a polyamide resin having a negative temperature coefficient and a melting softening point in a temperature range of 140 to 180° C., coated to a thickness of 05 to α05+mn, 5 is the outer side of the core yarn 1 and the thermosensitive layer 2 A temperature fuse layer 6 is made of a crystalline resin having a melting point of 150 to 1°90°C, such as polyamide resin, copolymerized polyester resin, polypropylene resin, polyvinylidene fluoride resin, polyacetal resin, etc., and is coated on the outer periphery by extrusion molding. A heating wire made of copper, copper alloy, etc. that has a heating effect is spirally wound around the outer periphery of the temperature fuse layer 5, and 7 is a polyester coated by extrusion molding around the outer periphery of the temperature fuse layer 5 and the heating wire 6. It is an insulating jacket made of vinyl chloride.

The operation of the above configuration will be explained next.

FIG. 2 shows the temperature dependence characteristics of the impedance of the embodiment of the heat-sensitive wire shown in FIG. 1 and the conventional example of the cord-shaped sensing wire shown in FIG.

FIG. 3 shows the impedance change characteristics over time of the embodiment of the heat-sensitive wire shown in FIG. 1, the conventional example of the cord-shaped sensing wire shown in FIG. 5, and aging at a temperature of 120°C.

The core thread 1 is the detection wire 3. Sensitive to heat82. Core yarn 1. Since it is necessary to form an electrical circuit with the loop of the heat-sensitive layer 2 and the detection wire 4, it must have conductive properties and mechanical strength as a core material. Carbon fiber is suitable for the conductive core thread 1, but conductive particles such as carbon, nickel powder, silver powder, etc. can be used as a total binder on the surface of polyester fiber, heat-resistant polyamide fiber, glass fiber, etc., such as urethane resin, acrylic resin, polyester resin, etc. 6 to 90 gium powder etc.
A composition containing 30% by weight is coated and dried and baked to make it conductive, or a polyester fiber or heat-resistant polyamide fiber is made conductive by nickel plating on its surface, or a conductive resin is tubed around the outside of the heat-resistant fiber. It may be something you have done.

The heat-sensitive layer 2 has excellent adhesion because it is coated on the surface of the detection wires 3 and 4 by enamel treatment, and since it is mechanically wrapped around the conductive core thread 1, the contact area is large and reliable. As shown in FIG. 2, the temperature dependence of impedance is greater than in the conventional example shown in FIG. 5, and the temperature detection sensitivity is excellent. In addition, the heat-sensitive layer 2 is formed by dissolving the resin with a solvent and adjusting its viscosity to form the detection line 6.
．． The thickness of the film formed on the surface of 4 is 0.005 to 0.0.
5mr+, the addition amount of additives such as quaternary ammonium salts, imidacillin compounds, oxazoline compounds, etc. to improve therminuta characteristics can sufficiently lower the impedance and increase the B constant even if the amount is around 1% by weight.
As shown in FIG. 6, when the heat-sensitive wire is left at a high temperature of 120° C., the change in impedance over time can be significantly smaller than in the conventional example.

In the examples, the reason why the change in impedance over time f is kept small is because the amount of additive for improving thermistor characteristics is small, and because the heating layer 5, which is a crystalline resin, is on the outer periphery, it acts as a kind of shielding layer and prevents the additive from entering. By preventing migration.

The temperature fuse layer 5 has a function of cutting off the current flowing to the heating wire B when the heat-sensitive wire reaches an abnormal temperature state. For example, if an element in the temperature control circuit breaks down and normal temperature control becomes difficult, the amount of heat generated by the heat-sensitive wire 2 increases, and the heat-sensitive wire 1
When the temperature exceeds 00°C, the heat sensitive layer 2 and the temperature fuse layer 5 have a negative temperature coefficient, so the impedance becomes extremely small, and the leakage current flowing between the detection wires 6, 4 and the heating wire 6 increases, thereby controlling the temperature. A safety circuit provided in the circuit is operated to interrupt the current flowing through the heating wire 6, thereby preventing burns to the two human bodies and burnout of the planar heating device.

In addition, assuming that the temperature of the sheet heating device during use reaches an abnormal temperature due to external heating, the temperature of the heat-sensitive layer 2 will be 140 to 180℃.
The temperature fuse layer 5 also has a property of melting and softening at 150°C.
Since it melts at ~190°C, the detection wire 6.4 and the heating wire 6 cause a contact short circuit, causing an excessive short circuit current to flow, which activates the safety circuit and interrupts the current flowing to the heating element B. .

The reason why the melting point of the temperature fuse layer 5 is limited to 150 to 190°C is as follows. If the melting point is less than 150° C., the heat aging resistance and bending strength will be reduced, or erroneous melting will occur, and if it is more than j9Lit, the planar heating device will easily burn out, which is not preferable.

The reason why the melting and softening point of the heat sensitive layer 2 is set to 140 to 180°C is that if the temperature fuse layer 5 is also about 10°C lower, the detection wires 6, 4 and the heating wire 6 are more likely to short-circuit in the event of an abnormal temperature. This is to make it happen.

Since the heat sensitive layer 2 and the temperature fuse layer 5 have similar physical properties as described above, abnormal temperature conditions can be detected and burns and burnouts can be prevented. The temperature fuse layer 5 is made of nylon 11. Although a single material such as nylon 12 or modified nylon 11 can perform its function, the thermistor properties added to the heat-sensitive layer 2.

The detection sensitivity of abnormal temperatures can be improved by adding a compound of the same quality or type as the improving additive.

The heat-generating wire 6 is suitably shaped in foil because it is necessary to keep the outer diameter of the heat-sensitive wire small and to increase the contact surface with the temperature fuse layer 5, whereas the detection wires 3 and 4 are shaped like heat-sensitive layer 2. A round shape with an outer diameter of 0.1 to 0.3 rrrm is preferable in order to ensure a thin and uniform coating and to ensure flexibility of the heat-sensitive wire.

As is clear from the structure shown in Figure 1, it is a heat-sensitive wire that uses a single cord-like object to generate heat and detect both normal temperature and abnormal temperature. A low-cost planar heating device can be obtained with fewer manufacturing steps. Furthermore, since a temperature control circuit can be constructed separately for the pair of detection wires 6, 4 and the heating wire 6, the impedance of the heat-sensitive layer 2 can be detected by applying an alternating current electric field between the pair of detection wires 6, 4. .

Therefore, even if an ionic additive is added to the heat-sensitive layer 2, no polarization phenomenon occurs and the characteristics do not change. Further, in this embodiment, the heat-sensitive layer 2 was formed on both of the detection lines 5 and 4, but it may be formed on only one side.

Effects of the Invention As detailed above, the present invention can be expected to have the following effects, and therefore has great industrial utility value.

(1) Just by arranging one heat-sensitive wire in a meandering manner on a planar heating device, it has both normal temperature detection and abnormal temperature detection functions, and the installation workability can be significantly improved.

(2) Flexibility as a planar heating device is ensured, and foldability is improved and discomfort during heating can be reduced.

(3) A structure with high temperature detection sensitivity can be obtained.

(4) Long-term reliability with small changes in characteristics over time.

(5) Manufacturing costs are lower.

[Brief explanation of the drawing]

Figure 1 is a structural diagram of a heat-sensitive wire showing an embodiment of the present invention, Figure 2
The figure is a temperature characteristic diagram of impedance between an embodiment of the present invention and a conventional example, FIG. 3 is a characteristic diagram of impedance change rate during heat aging between an embodiment of the present invention and a conventional example, and FIGS.
Each figure shows a structural diagram of a heat-sensitive wire showing a conventional example. 1... Core yarn, 2... Heat sensitive layer. 6.4...Detection line, 5...Temperature fuse layer. 6...Heating wire, 7...Insulating jacket.

Claims (1)

[Claims] 1. A pair of detection wires (3) and (4) spirally wound in parallel around the outer periphery of the core thread (1), and a 150-190° C. A fuse layer (5) made of a crystalline resin having a melting point of ), in which the core thread (1) has conductivity and the sensing wire (3), (
4) A heat-sensitive wire characterized in that a heat-sensitive layer (2) having a negative temperature coefficient is provided on at least one surface of the heat-sensitive wire. 2. The heat-sensitive wire according to claim 1, wherein the core yarn (1) is carbon fiber or a heat-resistant fiber whose surface is coated with a conductive film. 3. The heat-sensitive wire according to claim 1, wherein the heat-sensitive layer (2) is coated on at least one surface of the detection wires (3) and (4) by enamel varnish treatment.