JPS6386382A - Manufacture of heater unit - Google Patents

Abstract

(57) [Abstract] 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 method for manufacturing a heater unit in which a cord-shaped heating element is arranged in a meandering manner for use in a heating panel or a defrosting heater for a refrigerator/freezer.

Conventional technology Conventionally, this type of heater unit was manufactured by, for example,
This method is disclosed in Japanese Patent No. 534 and Japanese Utility Model Application Publication No. 178991/1983.

That is, according to Japanese Patent Publication No. 49-7534, a cord-shaped heating element, in which a thermoplastic resin layer is applied to the outermost layer of a heating element coated with a non-softening insulating material, is pressed and heated onto a thin metal plate, and the thermoplastic resin is then heated. The layers were melted and bonded to a thin metal plate.

According to Japanese Utility Model Application Publication No. 60-178991, a metal body is coated on the insulating outer layer of a cord-shaped heating element.

This metal body was coated with a thermoplastic jacket having a melting point lower than that of the insulating jacket, and then this thermoplastic jacket was heat-welded to the planar body.

Problems to be Solved by the Invention However, the conventional heater unit
Publication No. 7534 discloses that since the contact surface between the cord-shaped heating element and the metal thin plate is 20q6 or less, the heat transfer efficiency from the cord-shaped heating element to the metal thin plate is poor, and the bonding between the cord-shaped heating element and the metal thin plate is made using a thin adhesive. Because the welding occurs in a small area between the thermoplastic resin layer and the thermoplastic resin layer, local overheating may cause the cord-shaped heating element to separate from the thin metal plate or reduce the reliability of the bonding after long-term use. Since it uses a non-softening insulator, it becomes expensive.

In addition, in Japanese Utility Model Application Publication No. 60-178991, since the cord-shaped heating element and the planar body are joined using a thermoplastic jacket and there are few joint surfaces, it is possible that the cord-shaped heating element and the sheet-shaped body may come off when abnormal overheating occurs or for a long period of time. The adhesion reliability during use is poor, and since the metal body is covered, the metal body wrapped around the bent part of the cord-shaped heating element may become embedded in the insulating layer, reducing the dielectric strength or decreasing the bending strength. These methods have disadvantages, such as reduced workability during meandering wiring, and increased cost due to the complicated structure of the cord-shaped heating element.

Means for Solving the Problems The present invention has been made to eliminate the drawbacks of the prior art.
A first step of arranging a cord-shaped heating element in an appropriate shape, the outermost part of which is provided with a heat-fusible covering.

A second step of welding the heat-fusible coating and the heat-fusible thin body by applying heat and pressure to the cord-like heating element with the heat-fusible thin body provided on at least one surface of the thin metal plate. and a third step of integrally molding the thin metal sheet around the outer periphery of the cord-shaped heating element by applying pressure to the thin metal sheet by bringing the elastic bite-shaped body into contact with the side of the thin metal sheet.

After the cord-shaped heating element is welded to the heat-sealable thin body provided on the surface of the metal thin plate, the metal thin plate is press-formed through an elastic body from the side of the metal thin plate, and the metal thin plate is shaped into a cord. By integrally surrounding the surface of the heating element, heat diffusion from the cord-shaped heating element to the metal thin plate body is greatly improved. Moreover, since the metal thin plate-like body mechanically holds the cord-shaped heating element, the cord-shaped heating element is not scratched and does not generate local heat generation.

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

FIG. 1 shows an embodiment of the heater unit of the present invention, in which a heating wire 6 is spirally wound around the outer periphery of a core thread 2, and then a heat-fusible chloride film having insulating properties is formed. Donil,
This is a cord-shaped heating element consisting of a covering body 4 made of tubing made of thermoplastic elastomer or the like by extrusion molding. 5 is a thin metal plate such as aluminum foil having a thickness of CLO3 to 0.2+m++ and has good thermal conductivity; 6 is a thin metal plate laminated on the surface of the thin metal plate 5 by lamination in advance;
It is a heat-fusible thin body having a thickness of a01 to 0.1 m and made of a material 9 that can be welded to, such as vinyl chloride, vinyl acetate, polyolefin, etc. The cord-shaped heating element 1 is arranged in a meandering manner in a first step, and the metal thin plate-shaped body 5 is placed so that the heat-fusible thin-shaped body 6 is on the cord-shaped heating element 1 side.

A second step of welding the covering body 4 and the heat-fusible thin body 6 by applying pressure at a temperature of 120 to 250°C for 1 to 10 seconds, and an elastic molded body 91, for example 5 to 20
50 to 300 with a foamed rubber sheet
By pressurizing with a pressure of /crI, the metal thin plate 5
is molded to surround the cord-shaped heating element 1.
It consists of a process.

FIG. 2 shows another example of the structure of the cord-shaped heating element 1 used in the present invention. 2 is a core thread made of fibers such as polyester or glass; 6 is a metal heating wire wrapped around the outer periphery of the core thread 2; 7 is an insulation made of vinyl chloride, silicone rubber, etc., which is extruded into tubing around the outer periphery of these wires. layer, 4
is a heat-fusible covering made of polyolefin, polyester, thermoplastic nidistomer, etc., which is formed by extrusion forming a tube around the outer periphery of the insulating layer 7. By providing the heat-fusible covering 4 around the outer periphery of the insulating layer 7, welding in the second step becomes more reliable, and the contact area with the metal thin plate 5 is increased, increasing the efficiency of heat diffusion. It is intended to improve

FIG. 6 shows the heater unit shown in FIG. 1 as a planar heating element, and 1 is a cord-shaped heating element.

4 is a heat-fusible covering provided on the outermost part of the cord-shaped heating element 1; 5 is a thin metal plate; 6 is a thin metal plate laminated in advance on the surface of the thin metal plate 5 and welded to the cover 4; Thickness 0.
01 to 0.1 mm thick heat-fusible thin body such as vinyl chloride or thermoplastic elastomer, 8 is a metal that is joined to the metal thin plate-like body 5 by melting the heat-fusible thin body 6 from the thermocompression bonding example. The thin metal plate 5 is a base material such as a plate or a synthetic resin member, and is pressure-molded before being joined to the base material 8 and is integrally enclosed around the outer periphery of the cord-shaped heating element 1 .

Next, the operation of the above configuration will be explained.

FIG. 4 shows the temperature distribution characteristics on the surface of the heater unit of the nine embodiments of the present invention and the conventional example.

The heater units of the embodiment and the conventional example have the configurations shown in Table 9-1.

The example includes a first step of arranging the cord-shaped heating elements 1 in a meandering manner so that the pitch is 30 volts, and welding the cord-shaped heating elements 1 and the thin metal plate 5 by thermocompression bonding at 180° C. for 2 seconds. A heater unit is obtained from the second step and the third step of surrounding and integrating the thin metal body 5 with the surface of the cord-shaped heating element 1 under a pressure of 2oo kg/61.

On the other hand, in the conventional example, the cord-shaped heating elements were arranged in a meandering manner so that the pitch was 30, and then the cord-shaped heating elements and the thin metal plate were welded together by thermocompression bonding at 200° C. for 2 seconds to obtain a heater unit.

In the conventional example, the temperature difference between the surface of the cord-shaped heating element and the surface of the aluminum foil between the pitches was about 20°C, whereas in the example, it was about 9°C.
temperature difference, and the temperature distribution becomes uniform.

In addition, the maximum temperature of the surface temperature of the cord-shaped heating element is lowered in the example because of better heat diffusion than in the conventional example, and the cord-shaped heating element is less prone to thermal aging when used for a long period of time. It does not easily come off from the aluminum foil.

Table 1 The cord-shaped heating element 1 and the metal thin plate body 5 are formed by welding a heat-fusible covering 4 and a heat-fusible thin body 6, and then forming the metal thin plate body 5 into a cord shape. Since it is integrated with the outer periphery of the heating element 1, the heat generated from the cord-shaped heating element 1 is efficiently diffused into the thin metal plate 5, and the temperature distribution of the thin metal plate 5 is made uniform.

Further, since the five-piece metal thin plate-like cord-like heating element 1 is mechanically included and fixed, there is no possibility that the cord-like heating element 1 will come off from the metal thin plate-like member 5 and cause local overheating.

The single cord-shaped heating element used in the present invention has an outer diameter of 18 to 3.0 in order to easily arrange it in a meandering manner in the first step and to make it easier to surround and integrate it with the thin metal plate 5 in the sixth step. The outermost heat-adhesive coating 4 has a rubber hardness of 50 to 50.
It has a hardness of 120. If the hardness of the covering body 4 exceeds 120 in terms of rubber hardness, the pressing force will concentrate when the thin metal body 5 is pressure-formed in the third step and the aluminum foil will break, whereas if the hardness is less than 50. In this case, the deformation of the covering 4 is so large that it is difficult to press-form the aluminum foil. More preferably 6
A hardness of 0 to 100 is good. The covering 4 is a tubing made of a thermoplastic elastomer made of ethylene propylene resin and ethylene propylene rubber, which has both insulation and welding properties.

In addition to providing an insulating layer 7 such as vinyl chloride, materials such as polyethylene, vinyl acetate, and thermoplastic nitrogen are suitable.

Next, the heat-sealable thin body 6 fixed to the cord-shaped heating element 1 and the metal thin plate body 5 is melted and welded to the covering body 4 by thermocompression bonding in a second step. For example, if the covering 4 is made of vinyl chloride, the heat-fusible thin material 6 is made of vinyl chloride-based or polyester-based material, and if the covering 4 is an olefin-based thermoplastic elastomer, the heat-fusible thin material 6 is made of vinyl chloride-based or polyester-based material. Suitable materials include polyethylene, polypropylene, vinyl acetate, etc. Also.

If it is necessary to bond again to the substrate 8 such as a metal plate or synthetic resin by heat-pressing, a resin component containing polyester, olefin, etc. having a crystalline resin component is suitable.

Furthermore, the heat-sealable thin body 6 has a thickness of Q, 01 to α1 to ensure bonding strength between the metal thin plate body 5 and the substrate 8.

The metal thin plate-like body 5 is made of soft aluminum foil in order to surround and integrate the cord-shaped heating element 1 by pressure forming with a thickness of 50 to 300μ in the sixth step, and is made of soft aluminum foil with a thickness of 0.03 to Q, 2m. Good thickness. When the thickness is thinner than [103], it becomes easy to break during pressure molding and the heat diffusion properties are deteriorated, and when the thickness is thicker than a2■, it becomes difficult to pressure mold and cannot be integrated. More preferably 0.05~
A thickness of 0.1 m is suitable.

When the thin metal plate 5 is integrated with the surface of the cord-shaped heating element 1 in the sixth step, if pressure molding is performed while heating, the covering 4 or the insulation layer 7 will be thermally deformed and the insulation layer 7 will be thermally deformed. Since proof strength cannot be ensured, pressure molding is performed at a temperature that does not cause thermal deformation. The pressure applied to the thin metal body 5 through the elastic molded body 9 varies depending on the thickness and hardness of the cord-shaped heating element 1, the thickness of the thin metal body 5, etc., and is in the range of 9/i from 50 to 300. Select the optimal value. When performing pressure molding, when the cord-shaped heating element 1 side is set as a hard surface and the metal thin plate-shaped body 5 side is pressurized via the elastic molded body 9, the metal thin plate-shaped body 5 becomes the cord-shaped heating element 1.
Extends along the outer circumferential surface of the Elastic molded body 9 used at this time
Rubber with a foaming rate of 5 to 20 times is suitable.

Furthermore, when joining the thin metal body 5 and the base material 8 by thermocompression bonding again, the heater unit may be placed in a jig that does not apply significant pressure to the cord-shaped heating element 1.

Effects of the Invention The first step is to meander the cord-shaped heating element provided with the heat-fusible covering on the outermost part, and the cord-shaped heat-fusible thin body provided on the surface of the thin metal body. The second step is to place it facing the heating element and weld it by thermocompression bonding.

The primary heating unit is manufactured by manufacturing a heater unit from the sixth step of molding the metal thin plate body by applying pressure from the metal thin plate body side through the elastic molded body 9 and surrounding and integrating it with the surface of the cord-shaped heating element. The desired effect can be expected.

(1) Since heat diffusion from the cord-shaped heating element to the metal thin plate-shaped body is improved, the temperature distribution becomes uniform.

(2) Since the metal thin plate-like body mechanically holds the cord-shaped heating element and the cord-shaped heating element does not come off and cause local overheating, durability and reliability are improved.

(3) Since the cord-shaped heating element structurally does not reduce dielectric strength or flexibility, it has good wiring properties when manufacturing the heater unit, and can be manufactured at low cost.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the configuration of a manufacturing method of a heater unit according to an embodiment of the present invention, Fig. 2 is a side view of a cord-shaped heating element of the same place, and Fig. 3 is a surface shape to which the same heater unit is applied. FIG. 3 is a perspective view of the configuration of a heating element. FIG. 4 shows temperature distribution characteristics on the surface of the heater unit of the embodiment and the conventional example. 1... Cord-shaped heating element, 4... Covering body. 5...Metal thin plate body, 6...Heat-fusible thin body. 9... Elastic molded body.

Claims (1)

[Claims] A first step of arranging a cord-shaped heating element (1) having a heat-fusible covering (4) on the outermost part in an appropriate shape; The heat-fusible coating (4) and the heat-fusible thin body (6) are placed in contact with each other by heat-pressing the heat-fusible thin body (6) provided on at least one surface of (5). A second step of welding and pressing the elastic molded body (9) against the metal thin plate body (5) side causes the metal thin plate body (5) to be attached to the outer periphery of the cord-shaped heating element (1). A method for manufacturing a heater unit, comprising a third step of integrally molding the heater unit.