JPS59832A - Manufacture of heater - Google Patents

Abstract

PURPOSE:To decrease deformation, ununiformity, etc. in a heater leg part and obtain a heater of high quality under a stable condition of welding, by processing a primary coil, in which a heating wire is wound to a core wire, to form a secondary coil, forming an insulating film to the secondary coil, securing said secondary coil to a supporting body, and then immersing the coil in a solution to dissolve the core wire. CONSTITUTION:For instance, an Mo wire of 5.0MG and a W wire of 8.0MG containing 0.3 Re are used for a core wire to form a closely pitched part, and a rough pitched part is formed to both ends of the closely pitched part, then a primary coil is formed. Then the primary coil is processed to form a secondary coil having a main heating part 1a and a leg part 1b. While alumina powder containing a binding agent is coated from a heater point end by the method of spraying or the like, and alumina is heated and sintered in hydrogen at increased temperature. Then the leg part 1b is welded to a supporting body 2 of stainless steel or the like, and the coil welding a heater main unit to a heater supporting body is immersed in mixed acid then the Mo core wire is dissolved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Part 1 of the Invention) The present invention relates to a method for manufacturing a heater, and particularly to an improvement in a method for manufacturing a heater suitable for ultra-small energy-saving cathode ray tubes.

(Technical background of the invention and its problems) H-1-1 used in ultra-small energy-saving cathode ray tubes
An example is shown in FIG. The conventional method for manufacturing such heaters is to use a heating wire (such as tungsten or rhenium-containing tungsten).
1c) is wound around a core wire (1d) such as a molybdenum wire, and the primary coil is further wound into a coil shape to form a secondary coil. This is a so-called coiled double helical heater, which is coated with an insulating film (1e) such as Alcina. After sintering, the heater body (1) is obtained by immersing it in a mixed acid of sulfuric acid, nitric acid, and water, and dissolving and removing only the core wire. Next, the heater body (1) was shaped as necessary and resistance welded to the heater support (2) to form a heater.

Recently, there has been a demand for energy-saving cathodes for C-CRTs. In order to satisfy this requirement, the cathode structures are becoming smaller in size. The heater used for this has a smaller secondary coil diameter (φt), a smaller primary coil diameter (φj), and a thinner heating wire (1c) to make the heater shape smaller.
In order to improve thermal efficiency, the primary coil disposed near the main heat generating part (1a) is formed with a close pitch, and the leg part (1b) is formed with a coarse pitch primary coil. However,
Because the heating wire (IC) is thin, the heater is often deformed during the insulation film sintering process and the core wire melting process, especially the heater legs (1b) are not aligned. The heater legs were shaped if necessary before resistance welding to the support (2). The personnel costs for this are enormous. In particular, if the heater legs (1b) are uneven, if they are welded directly to the heater support, the position of the welding point will fluctuate, increasing the variation in heater current, and resulting in insufficient welding.

When a heater support and a heater body are automatically supplied and welded using an automatic welding machine, irregularities in the legs are fatal.

On the other hand, in the resistance welding method shown in Figure 2 where the pitch of the weld is coarse and the diameter of the heating wire is small, the welding is performed by applying a load to the electrode (4), which may cause the coil to collapse at the weld, resulting in failure of the cathode. The incidence of heater disconnection, which is the most serious of these, increases. Therefore, by welding by reducing the load applied to the electrode (4), the coil collapse will disappear, but the welding will become unstable (sparks will occur).
Unfortunately, the quality of the product deteriorates.

(Object of the Invention) The present invention has been made in view of the above circumstances, and it is possible to reduce the deformation and irregularity of the heater legs before welding them to the heater support, thereby eliminating the need for shaping the legs and creating a stable Welding shape (condition)
To provide a method for manufacturing a heater with high quality.

(Summary of the invention) The present invention includes a process of forming a primary coil by winding a heating wire around a core wire, a process of processing this primary coil to form a secondary coil, and forming an insulating film on this secondary coil. a step of shaping the shape of the heater main body as necessary; a step of fixing the heater main body to a heater support; and a step of fixing the heater main body to the heater support. 1. A method for producing a heating element, comprising the step of dissolving the core wire in a core wire dissolving solution.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described in detail with reference to FIG. MG (weight per length 200i + sc, unit ■) molybdenum wire of 5.0 and MO 8.0 3% rhenium-containing palm tungsten wire, wound 8III times at a pitch of 0.06s + i to form a dense pitch part. Then, a primary coil is made by winding the coil on both sides in five orders of length with a pitch of 0.2 to form a coarse pitch part. Next, this primary coil was cut into a total length of 18 mm centering on the dense pitch part, and the outer diameter φ was 0.
A secondary coil having a main heating part (1a) with a length of 6 m, a length of 1.0 mm, and a number of turns of IJ metal x2 and a leg part (1b) with a length of 5.8 ysm is formed. Next, 425 from the heater tip
The trench was coated with alumina powder containing a binder to a thickness of 90 μm using a spray method, and the alumina was sintered by heating to 1700° C. in humidified hydrogen. Next, if there is any heater deformation, shape it as necessary. Next, the leg portion (1b) is welded to the heater support (2) made of stainless steel with a thickness of 0.17 mm using an automatic welding machine. Next, when the heater body welded to the heater support is immersed in mixed acid for 4 hours, only the sulfide wire is dissolved and the heater is completed. The above is 3% as a heating wire.
A rhenium-free tungsten wire as shown in the example of the rhenium-containing palm tungsten wire may also be used.

(Effects of the Invention) According to the present invention, since the heater body is welded to the heater support while the core wire is not melted, deformation and irregularity of the leg portions before welding are extremely small and only a slight adjustment is required. Can be welded using an automatic welding machine. Therefore, the labor cost for correcting the deformation, which was conventionally necessary, can be significantly reduced. In addition, since the heater body and heater support are welded with the core wire unmelted, there is no need to worry about the coil being crushed even if the welding part has a rough pitch because the core wire is still there. A stable solution shape (state) can be obtained, and a heater with good product quality can be obtained.

The coil pitch of the rope welding part is not just a coarse pitch υ, but even a regular pitch can produce the same effect as a coarse pitch.

[Brief explanation of the drawing]

Figure 1 (a) is a plan view showing an example of a heater used in an ultra-compact energy-saving cathode ray tube, (b) and (C) are sectional views of essential parts, and Figure 2 shows a conventional manufacturing method. Explanatory diagram, 3rd
The figure is an explanatory diagram showing the manufacturing method of the present invention.

Claims (2)

[Claims] (1) A process of winding a heating wire around a core wire to form a primary coil, a process of further winding this primary coil into a coil shape to form a secondary coil, and forming an insulating film on this secondary coil. A process of obtaining a heater body, a process of shaping the shape of the heater body as needed, a process of fixing the heater body to a heater support, and a process of fixing the heater body to the heater support with a core wire. A method for manufacturing a heater, comprising the step of immersing the core wire in a solution to dissolve the core wire. (2) The method for manufacturing a heater according to claim 1, wherein the core wire is made of molybdenum, the heating wire is made of tungsten or rhenium-containing tungsten, and the heater support is made of stainless steel.