JPH04319247A - Electric element wrapped with insulating tube and its manufacture - Google Patents

Abstract

PURPOSE:To provide an electric element wrapped with an insulating tube which can be attached to the surface of a composition able to be formed economically and having a curvature such as a heater element prepared at low manufacturing cost and in a few manufacturing processes and/or a temperature detecting device easy to be attached and able to detect temperature accurately. CONSTITUTION:A liquid-phase thermosetting silicone rubber is applied to the inside of a silicone rubber tube 1 having high thermal conductivity. A diode-type thermistor 4 is put in almost the center of the silicone rubber tube 1. The resulting body is pressed and heated by a thermal press and the inside faces of the silicone rubber tube except the part where the diode-type thermistor 4 is located are stuck closely each other.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrical element encapsulated in an electrically insulating tube and a method for manufacturing the same. More specifically, the present invention relates to an electrical element encapsulated in an insulating tube formed into a shape that can easily come into contact with a structure having a curvature on its surface, such as a fluorescent tube or general piping, and a method for manufacturing the same.

0002

2. Description of the Related Art For example, heat-retaining heaters are used in copying machines, facsimile machines, backlights of various instruments, etc. in order to stabilize the amount of light emitted from fluorescent tubes for exposure even in low-temperature environments.

FIG. 5 is a perspective view showing the state of a heat-retaining heater attached to a fluorescent tube (not shown), and FIG. 6 is a perspective view showing an example of a temperature sensor used in the heat-retaining heater of FIG. It is. This heat-retaining heater has a structure in which a cord-shaped heater 12 as a heater element is sandwiched between two aluminum foils 11, 11 having adhesive layers. This heat-retaining heater has a hole 13 in its center and is fixed to the surface of the fluorescent tube with a holder or double-sided adhesive tape. The temperature sensor is shown in Figure 6.
As shown in the figure, a temperature sensing element 15 is arranged on the surface of the silicone rubber sponge 14, and is pressed against the fluorescent lamp through the hole 13 of the heat-retaining heater and fixed with a holder so that the temperature sensing element 15 faces the fluorescent lamp. Ru.

[0004] In addition, as a heat-retaining heater, one shown in FIG. 7 is used. FIG. 7 is an exploded perspective view of another heat-retaining heater. This heat retention heater uses metal foil 1
6 is formed into a serpentine pattern by punching or etching, and a polyester resin film 1 is formed on both sides of the film.
This is a so-called laminate heater made by stacking 7 and 17 and heating them under pressure. FIG. 8 is a sectional view showing the fixing structure of the temperature sensing element of the fluorescent tube. To detect the temperature of the laminate heater, an egg-shaped temperature detection element 18 is used as shown in FIG. 8, and is fixed to the surface of the laminate heater 19 with tape or a heat shrink tube 20.

[0005]

[Problem to be Solved by the Invention] All of the above-mentioned heat-retaining heaters are sandwiched between two planar bodies such as aluminum foil or polyester resin film, and it is necessary to precisely place the planar bodies on both sides of the heater element. It is necessary to overlap and cut the misaligned parts of the mating surfaces (edges). The laminate heater shown in Figure 7 has a lower product cost and is more economical than the heat-retaining heater (see Figure 5), which has a cord-shaped heater sandwiched between aluminum foil, but because of its rigidity, it does not stick tightly to the surface of the fluorescent tube. It has drawbacks such as being difficult to use. Furthermore, the laminate heater can be shaped into a curved shape so that it comes into close contact with the surface of the fluorescent tube, but this requires a new manufacturing process.

[0006] The temperature detection of the above-mentioned heat-retaining heater depends on a small heat-sensitive part of the temperature detection element, especially as shown in FIG.
It is difficult to adjust the installation pressure for the temperature sensor shown in Figure 2. If the pressure is not pressed properly against the fluorescent tube, the heat-sensitive part may shift, and if it is pressed too hard, the heat-sensitive part may sink into the sponge, making it difficult to accurately measure the temperature. The drawback was that it could not be detected. Further, the temperature sensing element shown in FIG. 8 has an oval outer shape,
Since the mounting surface is curved, a gap is created between the temperature sensing element, the mounting surface, and the fixing tape or fixing shrink tube, resulting in poor sensitivity. Furthermore, since the egg-shaped temperature sensing element is attached to a curved surface, the installation workability is extremely poor, and it also tends to shift from a fixed position during installation or use, resulting in variations in sensitivity.

An object of the present invention is to solve the above-mentioned drawbacks, and to provide a heater element and/or device which is low in product cost and requires few manufacturing steps.
Another object of the present invention is to provide an electrical element covered with an insulating tube that can be economically molded and easily attached to the surface of a structure having a curvature, such as a temperature sensing element that is easy to attach and can accurately detect temperature, and a method for manufacturing the same.

[0008]

[Means for Solving the Problems] In order to achieve the above object, an insulating tube-encapsulated electric element according to the present invention includes a temperature sensing element and/or a heater element disposed as an electric element in an extruded insulating tube, and It is characterized in that the inner surfaces of the insulating tubes are in close contact with each other except for the part where the element is located. The manufacturing method is characterized in that after the electric element is placed inside the extruded insulating tube, the inner surfaces of the insulating tube are brought into close contact with each other except for the portion where the electric element is located by applying pressure and heating using a hot press.

[0009]

[Operation] According to such a configuration, the electric element is covered with an insulating tube, and the inner surfaces of the insulating tube, excluding the part where the electric element is located, are brought into close contact with each other by heat pressing to form a flat or temperature-detected surface and/or Or, since it is formed into a curved shape with approximately the same curvature as the mounting surface of the heated surface, it is particularly easy to install on a mounting surface with curvature, increasing the thermal conductivity between the electrical element and the mounting surface, and allowing the electrical element to detect temperature. When the electric element is an element, the response can be improved, and when the electric element is a heater element, the thermal efficiency can be improved. Furthermore, although the insulating tube-covered electric element of the present invention is very similar in shape to a laminate heater, it uses an extruded tube as the insulating enveloping material instead of a laminate film, resulting in a low product cost.

[0010] According to the manufacturing method as described above, the manufacturing operation is simple and the number of manufacturing steps is small, and no special manufacturing process is required even if the product is to be formed into a curved surface. Furthermore, because an extruded insulating tube is used as the insulator to enclose the electrical element, unlike the case where the electrical element is placed between two sheets, there is no need to precisely overlap the sheets, and the mating surface There will be no misalignment. Therefore, there is no need to cut the end portions, and manufacturing workability is excellent.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in more detail below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the insulating tube-covered electric element according to the present invention, FIG. 2 is a perspective view showing the manufacturing process of the insulating tube-covered electric element according to the present invention, and FIG. It is a sectional view showing the manufacturing process of the envelope electric element. In Fig. 2, the inner diameter is 20 mm and the wall thickness is 0.
Liquid thermosetting silicone rubber 2 is sufficiently applied to the inner surface of a highly thermally conductive silicone rubber tube 1 having a diameter of 4 mm and a length of 30 mm. The silicone rubber tube 1 having high thermal conductivity is made by blending silicone rubber with alumina silica, zinc oxide, a small amount of boron nitride, etc., and is made by extrusion molding.

Next, a diode type thermistor 4 is attached to the tip of the lead wires 3, 3 as a temperature detection element by caulking terminals 5, 5.
The subassemblies connected by the above are arranged approximately in the center of the tube 1. As shown in FIG. 3, such an intermediate body 6 is placed in molds 7, 7 having the same diameter as a φ32 mm fluorescent tube, and the silicone rubber tube 1 is folded by heat pressing, and the opposing inner surfaces are thermoset over the entire surface. As the silicone rubber 2 is vulcanized, it is adhered to form the insulating tube-encased electrical element shown in FIG.

[0013] Here, the molding surfaces of the molds 7, 7 have a thickness of 3 m.
m silicone rubber sponges 8, 8 are installed,
This prevents damage to the thermistor due to pressure during molding. The bonding conditions were: temperature 120℃, time 30 minutes, pressure 1kg.
f/cm2. Note that the symbols in Figure 1 refer to Figures 2 and 3.
This is the same as shown in .

In order to investigate the temperature detection performance of this example, the insulating tube-encased electric element shown in FIG. 1 was fixed on the surface of a φ32 mm aluminum tube whose temperature was precisely controlled to 40.0° C., and temperature detection was carried out. When the resistance value of the thermistor was converted into temperature, it was 39.6°C. On the other hand, when measured using the temperature detector shown in FIG. 6 under the same measurement conditions, the detected temperature was 38.5°C.

As is clear from the above description, in the insulating tube-encased electric element of this embodiment, the outer skin surrounding the temperature sensing element has high thermal conductivity and is formed into a curved shape.
It collects heat from a wide area and enables accurate temperature detection. In this embodiment, a thermistor is used as the temperature sensing element, but a thermocouple may also be used.

Furthermore, in the insulating tube-encapsulated electrical element of this embodiment, the temperature sensing element is encapsulated in a highly flexible silicone rubber tube and has a curved outer shape. Easy to install and has superior installation workability compared to conventional temperature detectors.

In the previous example, a temperature sensing element was used as the electric element covered by the insulating tube, but when an etching heater element is used as shown in FIG. 4, a heat retaining heater with excellent thermal efficiency can be obtained. FIG. 4 is a perspective view showing another embodiment of the electric element according to the present invention, where 9 is a metal foil and 10 is a silicone rubber tube. It is also possible to arrange the temperature sensing element and the heater element within the same tube.

[0018]

Effects of the Invention As explained above, since the insulating tube-encapsulated electric element of the present invention is formed in a flat or curved shape, it can be brought into surface contact with a curved surface of a fluorescent tube, etc. As shown in the example, when the electric element is a temperature sensing element, the response is excellent and the sensitivity error due to the mounting method is extremely small. Further, when the electric element is used as a heater element, the mounting surface can be efficiently heated. The manufacturing method is a simple method of molding by hot press, and is superior in manufacturing workability and mass productivity compared to a method in which sheets are pasted together and molded into the same shape.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of an electrical element encapsulated in an insulating tube according to the present invention.

FIG. 2 is a perspective view showing the manufacturing process of the insulating tube-encapsulated electrical element according to the present invention.

FIG. 3 is a cross-sectional view illustrating a manufacturing process of an electrical element encapsulated in an insulating tube according to the present invention.

FIG. 4 is a perspective view showing another embodiment of an electrical element encapsulated in an insulating tube according to the present invention.

FIG. 5 is a perspective view showing a state of a heat-retaining heater attached to a fluorescent tube (not shown).

6 is a perspective view showing an example of a temperature sensor used in the heat-retaining heater of FIG. 5. FIG.

FIG. 7 is an exploded perspective view of another heat-retaining heater.

FIG. 8 is a sectional view showing a fixing structure of a temperature sensing element of a fluorescent tube.

[Explanation of symbols]

1 Silicone rubber tube 2 Thermosetting silicone rubber 3 Lead wire 4 Diode type thermistor 5　Caulking terminal 6 Intermediate 7 Mold 8 Silicone rubber sponge 9 Metal foil 10 Silicone rubber tube 11 Aluminum foil 12 Cord heater 13 Hole 14 Silicone rubber sponge 15 Temperature sensing element 16 Metal foil 17 Polyester resin film 18 Temperature sensing element 19 Laminate heater 20 Heat shrink tube

Claims (4)

[Claims] 1. An insulating tube-encased electrical element in which an electrical element is disposed within an insulating tube, characterized in that the inner surfaces of the insulating tube are in close contact with each other except for the portion where the electrical element is located. electric element. 2. A method for manufacturing an electrical element encapsulated in an insulating tube, in which the electrical element is arranged in an insulating tube, and after the electrical element is arranged in the insulating tube, the electrical element is heated under pressure using a heat press. A method for producing an electrical element covered with an insulating tube, characterized in that the inner surfaces of the insulating tubes are brought into close contact with each other except for the portion where the insulating tube is located. 3. In an insulating tube-encapsulated electrical element in which an electrical element is placed inside an insulating tube, an electrical element is placed inside an extruded silicone rubber insulating tube with excellent thermal conductivity and whose inner surface is coated with thermosetting silicone rubber. An insulating tube-encased electric element characterized in that a temperature sensing element and/or a heater element is arranged as the element, the inner surfaces of the insulating tube are brought into close contact with each other except for the part where the electric element is located, and the whole is formed in a curved shape. . 4. A method for producing an electrical element encapsulated in an insulating tube, in which an electrical element is disposed within an insulating tube, in which the inside of the insulating tube is extruded from silicone rubber with excellent thermal conductivity and whose inner surface is coated with thermosetting silicone rubber. After arranging a temperature sensing element and/or a heater element as an electric element, the temperature sensing element and/or the heating element are heated using a heat press machine equipped with a mold having a curvature approximately equal to the mounting surface of the temperature sensing surface and/or the heating surface. 1. A method for producing an electrical element covered with an insulating tube, characterized in that the inner surfaces of the insulating tube, except for the portion where the electrical element is located, are brought into close contact with each other by pressure heating to form a curved surface as a whole.