JP2567977Y2 - Cord-shaped heating element - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicone rubber insulated cord-shaped heating element made of stainless steel braid, and more particularly, it is used for heating and keeping the temperature by being wound around a compressor of a cooling and heating / heating device and energized. It relates to a cord-like heating element.

[0002]

2. Description of the Related Art Conventionally, cord-shaped heating elements have been widely used for keeping the heat of a compressor of a cooling and heating / heating device, for keeping a vending machine, a water heater or the like or for preventing freezing.

Here, the cord-shaped heating element is constructed by extruding and coating silicone rubber on the heating wire, and after vulcanization, a stainless steel wire is further added for the purpose of protecting the silicone rubber coating, which is generally difficult in mechanical strength. In general, a cord-like heating element which is braided is connected to both ends of a silicone rubber insulation-coated lead wire via connectors, and the connectors are insulated and waterproofed by silicone rubber molding.

[0004] In addition, a silicone rubber tube is placed over the insulation of the connector, and a liquid silicone rubber is poured between the connector and the tube to provide insulation and waterproofing, or to protect the mechanical strength of the silicone rubber insulation-coated lead wire. There are a glass braid, a glass braid, a polyvinyl chloride, a polyethylene or the like covered with a tube for the purpose, and these are appropriately combined to constitute a cord-shaped heating element.

Hereinafter, a conventional example will be described in more detail with reference to the drawings. FIG. 2 is a side view showing the structure of a cord-shaped heating element according to the conventional and the present invention. FIG. 3 is a side view showing the structure of a cord-shaped heating element assembly according to the conventional and the present invention. It is a side view which shows the example of use of the assembly of a heating element in a shape.

[0006] An assembly of a cord-like heating element used for keeping the temperature of a compressor of a cooling and heating / heating device generally is as shown in FIG.
Extrusion of silicone rubber on heating element 1 as shown in 2
After the vulcanization, the stainless steel wire is braided at a braid rate (cover rate) of 82%, and a mounting member 4 is attached to the cord-shaped heating element.
a and 4b are connected to each other, and the silicone rubber insulated wire 6 is connected to both ends of the cord-shaped heating element with the connector 5 as shown in FIG. 2, and the mounting spring 4 is mounted on the mounting bracket 4a and then connected. The element 5 is formed by molding 8 of silicone rubber to provide insulation and waterproofing.

Here, the stainless steel wire braid 3 is used for the purpose of protecting the silicone rubber coating, which has a problem in mechanical strength, and it is considered that the cover rate is appropriately about 82% for the purpose.

The assembly of the cord-shaped heating element is wound around a compressor 9 as shown in FIG. 4, and the mounting spring 7 attached to the mounting bracket 4a is stretched and hung on the mounting bracket 4b to be fixed by the tension of the mounting spring 7. Is done.

In general, the assembly of the cord-like heating element used for keeping the temperature of the compressor 9 of the cooling and heating / heating device is not turned on when the compressor is in operation but turned on when the compressor is stopped to generate heat. At this time, the surface temperature of the cord-shaped heating element is set to be equal to or lower than 180 ° C.

Conventionally, the electrical insulation life of an assembly of a cord-like heating element used for keeping the temperature of a compressor of a cooling and heating / heating device determined by the heat resistance life of silicone rubber is determined by the heat resistance of silicone rubber. 10 without physical forces, direct sunlight, corrosive gases or liquids
It was said to have a life span of about a year.

[0011]

[Problems to be Solved by the Invention] However, the present state of the electrical insulation life of the assembly of the cord-like heating element used for keeping the heat of the compressor of the cooling and heating / heating device was investigated, and it was found that the normal use method was not sufficient. Regardless, the service life is less than 10 years, and the silicone rubber insulator is partially deteriorated to cause insulation failure.
Some have deteriorated over the years. This deterioration occurred frequently in the portion of the compressor and the system where the condensed water adhered, and it was estimated that the water accelerated the deterioration of the silicone rubber insulator.

In general, a cord-shaped heating element is attached to a compressor of a cooling and heating / heating device to generate heat when energized, thereby keeping the compressor warm. %, The moisture retention such as dew condensation water of the compressor and its system adheres to the surface of the cord-like heating element, so that the water retention becomes high. When water molecules trapped in the silicone rubber insulator are vaporized by heating, the silicone rubber insulator undergoes hydrolytic degradation and softens, and at the same time, thermal expansion of the silicone rubber insulator occurs due to heating.

The higher the coverage of the stainless steel braid of the cord-shaped heating element, the greater the penetration of the stainless steel braid into the silicone rubber insulator during the above-mentioned thermal expansion, and cracks are generated by repeating this. It was considered that this would lead to insulation deterioration.

An object of the present invention is to solve the above-mentioned problems, and to provide a cord-shaped heating element having the original electrical insulation life of silicone rubber.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a silicone braided silicone rubber insulated cord-like heating element used for keeping the heat of a compressor of a cooling and heating / heating device. The braid ratio of the braid is set to 60 to 76%.

[0016]

The present invention reduces the water retention of the condensed water and the like by setting the stainless steel braid coverage of the cord-shaped heating element used for keeping the heat of the compressor of the cooling and heating / heating device to 60 to 76%. Further, by suppressing the stainless braid from biting into the silicone rubber insulator during the thermal expansion, the deterioration of the silicone rubber insulator of the cord-shaped heating element is suppressed.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As a test for accelerating the deterioration of the silicone rubber insulator of the cord-shaped heating element used for keeping the temperature of the compressor of the cooling and heating / heating equipment, the stainless steel braid coverage was set to 60-8.
Between 2% (Below 60% because the protection of silicone rubber coating is weak, and the stainless steel braid tends to come off in the processing process)
A voltage of 220 volts was applied to the variously changed cord-shaped heating elements in tap water at 80 to 90 ° C., and a continuous current of 2000
FIG. 1 shows the silicone rubber content obtained by thermogravimetric analysis of each silicone rubber after a lapse of time.

From this test result, it can be seen that when the stainless steel braid coverage of the cord-shaped heating element is 78% or more, the deterioration of the silicone rubber insulator is promoted, and the optimum braid coverage is 60 to 76%. It turned out to be.

Similarly, as a test for accelerating the deterioration of the silicone rubber insulator of the cord-shaped heating element used for keeping the temperature of the compressor of the cooling and heating / heating device, a stainless steel braided covering rate of the cord-shaped heating element is 82% and 74% compared with the conventional product. And 60% of the present invention in an autoclave at 132 ° C., 70% humidity, 2 atm, applying a voltage of 220 volts, conducting electricity for 22 hours, and taking out the surface of the cord-shaped heating element from which the stainless steel braid was removed. The state was observed, and the stainless steel braid mark was deeply carved on the surface of the silicone rubber insulator in the conventional product having a stainless steel braid coverage of 82%.

However, the stainless steel braid cover ratio 74
%, And 60% of the traces of the stainless steel braid of the product of the present invention were the same as before the test, and it was confirmed that there was almost no deterioration of the silicone rubber insulator.

[0022]

As described above, the present invention provides a stainless steel braided silicone rubber insulated cord-like heating element used for keeping the heat of a compressor of a cooling and heating / cooling device, and the braid ratio of the stainless steel braid is 60 to 76. % Of the cord-shaped heating element is used to keep the heat of the compressor of the cooling and heating / heating equipment, so that even if dew condensation water of the compressor and its system adheres, the electrical insulation life is maintained for the long term inherent in silicone rubber. can do.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing a deterioration promotion test result of an assembly of a cord-like heating element according to the present invention.

FIG. 2 is a side view showing the structure of a cord-shaped heating element according to the related art and the present invention.

FIG. 3 is a side view showing the structure of a cord-like heating element assembly according to the related art and the present invention.

FIG. 4 is a side view showing an example of use of a cord-like heating element assembly according to the related art and the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating element 2 Silicone rubber insulator 3 Stainless steel braid 4a, 4b Mounting bracket 5 Connector 6 Silicone rubber covered electric wire 7 Mounting spring 8 Silicone rubber mold 9 Compressor

Continuing on the front page (72) Shoichi Tobi 3-22, Takaidahondori, Higashiosaka-shi, Osaka Matsushita Refrigeration Machinery Co., Ltd. ) Inventor Miki Suzuki 4830 Takatsuka-cho, Hamamatsu-shi, Shizuoka Pref. Kurabe Co., Ltd.

Claims (1)

(57) [Scope of request for utility model registration] 1. A cord-shaped heating element in which a stainless steel braided silicone rubber insulated cord-shaped heating element used for keeping the temperature of a compressor of a cooling and heating / cooling device is 60 to 76%.