JPS61285690A - 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 the Invention The present invention relates to a heat-sensitive wire having a heat generation function and a temperature detection function used in planar heating devices such as electric blankets and electric car vents.

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, 9 is a core yarn made of polyester fiber, heat-resistant polyamide, etc.; 10 is a heating wire made of copper, copper alloy, etc., spirally wound around the outer circumference of the core yarn 9; 1
1 is a crystalline resin, such as nylon 11.1, which melts and softens at 150 to 190°C when the temperature becomes abnormal and has negative temperature characteristics. The fuse layer 12 is formed by extrusion-molding and covering the outer periphery of the core thread 9 of nylon 12 or the like and the heating wire 10. Leakage current flowing in or fuse layer 1
An abnormality detection wire 13 has a function of detecting a short circuit current flowing due to melting of the fuse layer 11 and operating a safety circuit of the control circuit to interrupt the heating current flowing through the heating wire 10; This is an insulating jacket made of polyvinyl chloride with an extrusion coating around the periphery.

Further, as shown in FIG. 5, the cord-like detection wire is a core thread 14 made of polyester, heat-resistant polyamide, or the like.

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

The corded heating wire and the corded detection wire are arranged in a meandering manner in a predetermined pattern on a planar heating device such as an electric blanket or an electric carpet, and are fixed to the same, and are combined with a control circuit to achieve a comfortable heating temperature. It's tight.

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 16 is determined by the internal detection line 15.
and external detection M17 to control the heating current flowing through the heating wire 10 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 line 12 detects the leakage current flowing through the fuse layer 11 and operates the safety circuit built into the control circuit to cut off the heating current flowing through the heating wire 10 to prevent burns to the human body or burnout of the sheet heating device. prevent it from happening.

In this way, the fuse layer 11 and the heat sensitive layer 16 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 these problems.

(1) Because the corded heating wires and corded detection wires are arranged in different meandering arrangement patterns and fixed, not only is workability poor, but if they are arranged overlapping each other, the sheet heating device will not work properly. It can become uneven or the cord can become crushed, which can easily 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 or the use of the material may be difficult. There is a sense of strangeness in time.

° (3) Since the inner detection wire 15 in FIG. The temperature-dependent performance of the current impedance cannot be fully exploited, and the temperature detection performance deteriorates.

(4) The thickness of the heat-sensitive layer 16 shown in Fig. 5 cannot be reduced to less than 0.2 mm due to extrusion molding technology constraints and mechanical strength. It is necessary to add a larger amount of quaternary ammonium salt to the leaf blade than 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. A pair of detection wires coated with a heat-sensitive layer having a negative temperature coefficient of 0.05 mm in thickness by enamel processing and an abnormality detection wire made of bare metal are wound in parallel in a spiral shape, and the outer periphery of these wires is to 15
A fuse layer is formed by extrusion molding a crystalline resin with a melting point of 0 to 190°C, and a heating wire is wound spirally around the outer circumference of the fuse layer, and then the whole is covered with an insulating jacket such as polyvinyl chloride. It has a covered structure.

Function The heat-sensitive wire structure of the present invention described above has the following functions, and its industrial utility value is considerable.

(1) A single cord-shaped heat-sensitive wire can detect normal temperature and abnormal humidity, 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) The thickness of the heat sensitive layer is α005 to 0.05++on
Because of the thin film.

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

(5) Detect the temperature between a pair of detection lines during normal times.

Abnormal temperature can be detected between the abnormality detection line and the heating line.

(6) 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 carbon fiber or polyester.

Conductive core yarn made of heat-resistant fibers such as heat-resistant polyamide or glass coated with conductive paint or nickel plating; A heat-sensitive layer made of a resin composition such as polyamide or epoxy having a negative temperature coefficient and coated with a thickness of 0.05 mm by enamel treatment; 5
6 is an abnormality detection wire made of copper, copper alloy, etc., wound in parallel with a pair of detection wires 6 and 4, and 6 is a core thread 1. 150 coated around the outer periphery of the heat sensitive layer 2 and the abnormality detection line 5 by extrusion molding.
A temperature fuse layer made of a crystalline resin having a melting point of ~190° C., such as polyamide resin, polyvinylidene fluoride resin, polyacetal resin, etc.; 7 is copper that has a heat-generating effect and is spirally wound around the outer periphery of the temperature fuse layer 6; A heating wire 8 made of copper alloy or the like is an insulating jacket made of polyvinyl chloride which is coated around the temperature fuse layer 6 and the heating wire 7 by extrusion molding.

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 when the example of the heat-sensitive wire shown in FIG. 1 and the conventional example of the cord-shaped sensing wire shown in FIG. 5 are aged at a temperature of 120°C.

The core thread 1 is the detection wire 3. Heat sensitive layer 2. 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 yarn 1, but it is also possible to use conductive particles such as carbon, nickel powder, silver powder, etc. on the surface of polyester fiber, heat-resistant polyamide fiber, glass fiber, etc. with a binder such as urethane resin, acrylic resin, or polyester resin. , Rhodium powder etc. 3~
Polyester fibers or polyester fibers made by applying a composition containing 30% by weight and drying and baking to make them conductive.

The surface of heat-resistant polyamide fibers may be nickel-plated to make them conductive, or a conductive resin may be tubed around the outer periphery of the heat-resistant fibers.

The heat-sensitive layer 2 has excellent adhesion because it is coated on the surfaces of the detection wires 6 and 4 by enamel processing, and since it is mechanically wrapped around the conductive core thread 1, the contact area between the two 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.
3) The thickness of the film formed on the surface of (4) is 0.0
05 to 0.05m, the addition amount of additives such as quaternary ammonium salts, imidacilline compounds, oxazoline compounds, etc. to improve thermistor characteristics can be sufficient to lower the impedance and increase the B constant even if the amount is around 1% by weight. As shown in FIG. 3, 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.

The reason why the change in impedance over time can be kept small in the example is that the amount of additive for improving the thermistor is small, and because the fuse layer 6, which is a crystalline resin, is on the outer periphery, it acts as a kind of shielding layer and prevents the migration of additives. This is due to the fact that it prevents

The abnormality detection wire 5 detects leakage current or short-circuit current by utilizing the property that the impedance of the temperature fuse layer B between the heating wire 7 and the heating wire 7 decreases or melts when abnormally heated, and interrupts the current flowing through the heating wire. This is a metal detection wire. For example, if an element in the temperature control circuit breaks down and normal temperature control becomes difficult.

When the heat generation amount of the heating wire 70 increases and the temperature of the heat sensitive wire reaches 100°C or more, the impedance of the temperature fuse layer B becomes significantly smaller, and the leakage current flowing between the heating wire 7 and the abnormality detection wire 5 increases. A safety circuit provided in the control circuit is operated to cut off the current flowing through the heating wire 7, thereby preventing burns to the two people's bodies and burnout of the planar heating device.

Furthermore, assuming that the planar heating device during use reaches an abnormal temperature due to external heating, the temperature fuse layer 6 is
When it melts at 190°C, the heating wire 7 and the abnormality detection wire 5 mechanically contact and short-circuit, causing a short-circuit current to flow, which is detected by the abnormal temperature detection a5 and activates the safety circuit provided in the control circuit. This prevents burns and burnout accidents by blocking the heating current flowing through the heating wire.

The reason why the melting point of the temperature fuse layer B is limited to 150 to 190°C is as follows. If the melting point is less than 150°C, it tends to reduce heat aging resistance or cause erroneous melting, and if it is more than 190°C, the planar heating device is likely to burn out, so both are undesirable, and more preferably 155 to 180°C. Suitable. The temperature fuse layer 6 is made of nylon 11, nylon 12. Although a single substance such as modified nylon 11 can perform its function, the detection sensitivity of abnormal temperatures can be improved by adding a compound that is the same or similar to the additive for improving thermistor characteristics added to the heat-sensitive layer 2. . On the other hand, since the heat-sensitive layer 2 does not need to function at abnormal temperatures, it may be either an unmelted composition or a molten composition at 150 to 190°C.

The heat-generating wire 7 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 6, whereas the detection wires 3 and 4 are shaped like heat-sensitive layer 2. In order to ensure thin and uniform coating and to ensure flexibility of the heat-sensitive wire, a round shape with an outer diameter of (11 to 0.3 mm) is preferable.

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 lines 6, 4 and the heat generating line 7, the impedance of the heat-sensitive layer 2 can be detected by applying an AC electric field between the pair of detection lines 3, 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 3 and 4, but it may be formed on only one of them.

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 pattern on a planar heating device, it has both normal temperature detection and abnormal temperature detection functions, and 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) Characteristics change little over time and have long-term reliability.

(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. 6 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. 3.4...Detection line, 5...Temperature fuse layer. 6...Heating wire, 7...Insulating jacket.

Claims (1)

[Claims] 1. A pair of detection wires (3), (4) spirally wound in parallel around the outer periphery of the core thread (1), and the detection wires (3), (
4), an abnormality detection wire (5) wound in parallel with the wire, a fuse layer (6) made of a crystalline resin having a melting point of 150 to 190° C. coated on the outer periphery of the wire, and an outer wire of the fuse layer (6). A heat-sensitive wire consisting of a heat-generating wire (7) spirally wound around the wire and an insulating jacket (8) covering the whole of the heat-sensitive wire, in which the core yarn (1) has conductivity and the detection wire (3
), (4) a heat-sensitive layer (2) having a negative temperature coefficient on the surface
A heat-sensitive wire characterized by being provided with. 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 the surfaces of the detection wires (3) and (4) by enamel varnish treatment.