JPS643195Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is used to operate indicators such as automobile fuel gauges, temperature gauges, and oil pressure gauges, or to operate constant voltage devices to obtain constant voltage to be supplied to these. This invention relates to bimetal heating wires used in bimetal meters.

Conventionally, this type of heating wire has been produced by coating a high resistance heating element 2, such as a nichrome wire, with two layers of polyamideimide fibers 1, as shown in Figure 1, and coating the polyamideimide fiber 1 with polyamideimide resin paint. Impregnated with
A device with a baking layer 3 formed thereon is widely used, and a device with three layers of glass fiber 4 wound around a high resistance heating element 2 as shown in Fig. 2 is also widely used. . However, in order to prevent the fibers from coming apart, the glass fibers 4 are impregnated with a silicone paint after the outermost layer is wound, and this silicone paint is coated with impregnation from the high resistance heating element 2. When heated, a gas consisting of benzoic acid is emitted, and in order to prevent contacts and instruments from being corroded by this gas, a baking hardening process is applied, followed by a heat treatment called dry baking.

By the way, when such a heating wire 5 is wound around a bimetal 6 as shown in FIG. 3 and used as a constant voltage device, a wire as shown in the figure is attached to the tip of the bimetal 6 around which the heating wire 5 is wound. As shown, a contact 7 is provided, and when the heating wire 5 of the bimetal 6 is energized and the bimetal is heated, the bimetal vibrates and the fixed contact 8 vibrates into contact and separation, thereby obtaining a constant voltage. As a result, by increasing the number of times the contacts 7 and 8 are connected and separated, a more stable constant voltage can be obtained.

However, the bimetal 6
When automatically wound, the coating is broken at the edges of the bimetal and loses its covering power (insulating property), causing a short circuit with the bimetal 6. Also, in order to eliminate this inconvenience,
It is also possible to use aramid fiber instead of the glass fiber mentioned above, but since this aramid fiber has poor thermal conductivity, the number of oscillations of the bimetal decreases to about 80 times per minute, which causes the indicator needle to oscillate. There was a problem that caused blurring.

This invention was made in order to eliminate the above-mentioned conventional drawbacks, and the purpose is to provide a bimetal heating wire that has excellent thermal conductivity and insulation properties, and can also obtain a high number of oscillations. That is.

The present invention will be described in detail below with reference to the embodiment shown in FIG. 4 and FIG.

In Figure 4, 11 is nickel, chrome,
The high resistance heating wire 11 is made of an aluminum alloy material, and the surrounding surface of the high resistance heating wire 11 includes:
A polyamide-imide baked layer 12 is formed on the circumferential surface of the high-resistance heating wire 11 by repeatedly applying a polyamide-imide resin directly and then baking the resin. Next, glass fiber yarn is wound in three layers around the outer periphery of this baked layer 12 to form a fiber-wound layer 13.
After forming, the fiber wound layer 13 is impregnated with a polyamide-imide resin paint 14, and the paint is further baked to complete the intended bimetallic heating wire 15. The embodiment shown in FIG. 5 differs from the previous embodiment only in that the glass fiber yarn is wound in two layers, and the other constructions are the same as the previous embodiment.

The above is the configuration of the heating wire for bimetal according to the present embodiment.Next, the function and effect will be described.As mentioned above, the first point required for the heating wire for bimetal is from the heating wire 11 to the bimetal. The second point is to improve the heat conduction of the bimetal and increase the number of oscillations of the bimetal.The second point is to prevent the insulation breakdown of the bimetal heating wire when it is wound around the bimetal. In other words, in order to improve heat conduction, it is possible to make the insulation coating thinner, but if the insulation coating layer is made thinner, the insulation properties will deteriorate, and if the insulation properties are increased, the insulation coating layer will inevitably become thicker. This reduces the thermal conductivity and the number of oscillations of the bimetal, but the bimetal heating wire according to this embodiment has a lower number of oscillations and insulation compared to the conventional bimetal heating wire. It is superior in terms of gender.

The effects of the heating wire according to this example will be explained below.

Example A polyamide-imide resin paint was applied and baked around a high-resistance heating wire 11 made of an alloy of nickel, chrome, and aluminum to form a polyamide-imide baked layer 12 of about 7.5 microns. Next, two to three layers of glass fiber are wound around the circumferential surface of the baked layer 12, and the glass fiber is further impregnated with polyamideimide resin, which is then baked at a temperature of 350 to 450°C to give approximately 60% A heating wire 15 is completed by forming a micron glass fiber coating layer. As a result of repeatedly measuring the number of oscillations of the bimetal 6 around which the heating wire 15 formed in this way was wound, the average value of the number of oscillations was as high as 128.3 oscillations per minute even when a bimetal with a small curvature constant was used. The number of times was obtained. Further, the heating wire 15 according to this embodiment is
Since a painted baking layer 12 of polyamide-imide resin is formed on the circumferential surface of the high-resistance heating wire 11, this baking layer 12 and the above-mentioned glass fiber coating layer together increase the insulation strength and improve the insulation fastness. This has the effect of providing a heat generating electric wire 15 with a high temperature.

As described above, in the present invention, the high resistance heating element 11 is
A polyamide-imide resin paint or a polyimide resin paint is coated and baked to cover it with a paint-coated and baked layer 12, and a plurality of layers of glass fiber are wound thereon to form a fiber-wound layer 13, and this fiber-wound layer 13 is coated with polyamide-imide. This heating wire for bimetal is characterized by being impregnated and baked with resin paint or polyimide resin paint, so when this heating wire is wound around bimetal, it has good thermal conductivity and bimetal vibration with a high number of oscillations. is obtained. Furthermore, since the paint baking layer 12 is formed on the surface of the heating element 11, and a coating layer of glass fiber and resin paint is further formed around it, it has an excellent insulation effect.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the configuration of a conventional heating wire, FIG. 3 is a perspective view of a bimetal around which a heating wire is wound, and FIG. 4 is a cross-sectional view of a heating wire according to the present invention. FIG. 5 is a sectional view of a heating wire showing another embodiment of the present invention. 11...Resistance heating wire, 12...Baked layer, 13...
...Fiber winding layer, 14...Paint, 15...Bimetal heating wire.

Claims (1)

[Scope of utility model registration request] The high resistance heating element 11 is coated with a paint coated and baked layer 12 by applying and baking a polyamide-imide resin paint or a polyimide resin paint, and a fiber wound layer 13 is provided by winding a plurality of glass fibers thereon. A bimetal heating wire characterized in that the winding layer 13 is impregnated and baked with a polyamide-imide resin paint or a polyimide resin paint.