JPS5937554B2 - Heating wire coil with terminal and its manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention is used as a component of a sheathed heater and the like.

Regarding the terminal-equipped heating wire coil (hereinafter referred to as "terminal-equipped coil") in which a terminal is connected to the heating wire coil (hereinafter referred to as "coil") and its manufacturing method, the terminal may be damaged by the tension applied in the manufacturing process of sheathed heaters, etc. The purpose is to prevent the coil from coming off or shifting. Generally, in a sheathed heater, a terminal-equipped coil with terminals at both ends is arranged in the center of a metal pipe, and an insulating material is filled between the terminal-equipped coil and the metal pipe.

A conventional terminal-equipped coil used in this sheathed heater is shown in FIG. In FIG. 1, reference numeral 1 denotes a coil as a heating wire made of nichrome wire or the like.

Metal terminals 2 are attached to both ends of the coil 1 and are made of iron, stainless steel, or the like.

The coil 1 and the terminal 2 are connected by inserting the terminal 2 into the end of the coil 1 by about 8 mm, and then welding and fixing the terminal 2 and the coil 1. In addition, 3 is terminal 2
This is the welded part between the coil 1 and the coil 1. In this way, the terminals 2 are attached to both ends of the coil 1, and a coil with terminals is completed.

In the manufacturing process of a sheathed heater, when the above-mentioned coil with a terminal is placed in the center of a metal pipe and its surroundings are filled with a heat-resistant insulating material such as magnesia, the coil 1 is strongly stretched as shown in FIG.

Therefore, the coil 1 is partially removed from the tip of the terminal 2.
Moreover, since the diameter of the metal pipe is reduced together with the coil with terminal and the heat-resistant insulating material inside the metal pipe, the metal pipe is elongated by 15 to 25%. At this time, the coil 1 is also strongly stretched at the same time as the metal pipe. Therefore, from the terminal 2 at the tip of the welded part 3 between the coil 1 and the terminal 2, the coil 1
The problem was that it came off. In addition, the coil 1 at the tip of the terminal 2 from the coil welding part 3 may shift during the manufacturing process, resulting in the electrical resistance of the completed heating wire being approximately 2 to 5% higher than the set value, which also has the disadvantage of causing variations in electrical resistance. Ta.
In order to prevent this, the welded part 3 between the terminal 2 and the coil 1 is provided near the tip of the terminal 2, so that the above-described drawback of the coil 1 coming off from the terminal 2 can be improved.
However, when the coil 1 is welded to the terminal 2, the coil 1 is deformed, so if tension is applied to the coil 1, tension is directly applied to the welded portion 3 of the coil 1. For this reason, there is a drawback that the coil 1 may break at the welded portion 3 to the terminal 2 during the manufacturing process. The present invention eliminates the drawbacks of the conventional terminal-equipped coils and prevents a portion of the coil from shifting at the connection between the terminal and the coil due to tension applied during the sheathed heater manufacturing process. Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 3, 11 is a coil, and 12 is a round bar-shaped terminal having a tapered portion at the tip. The end of the coil 11 is disposed on the outer periphery of the end of this terminal 12Q, and furthermore, this coil 11
The end of the coil 11 is covered with a metal tube 13 having a spiral groove on the inner surface and made of nickel, stainless steel, etc., and the end of the coil 11 is held between the terminal 12 and the metal tube 13. Note that 14 is a connection portion between the coil 11 and the terminal 12. A method of manufacturing this terminal-equipped coil will be explained. First, the end of the coil 11 is screwed a certain number of times into the groove of the metal tube 13, which has a spiral groove on the inner surface.
Attach the metal tube 13 to the end of the tube. After this, the terminal 12 is press-fitted into the end of the coil 11, and the tip of the terminal 12 is inserted into the coil 11.
Align it with the end of the metal tube 13 provided on the outer periphery of the metal tube 13. In this state, the heating wire used for the coil is held between the metal tube 13 and the terminal 12. After this, the metal tube 13 is welded,
The metal tube 13 and the coil 11 are welded and fixed to the terminal 12. The depth of the groove provided in the metal tube 13 is 30 mm of the diameter of the coil 11.
A good connection was achieved within the range of ~100%.

The terminal-equipped coil manufactured in this way does not allow the coil 11 to come off from the groove of the metal tube 13 even if tension is applied during the sheathed heater manufacturing process.

As is clear from the above explanation, according to the method of the present invention, it is possible to easily strengthen the connection between the coil and the terminal.
The terminal-equipped coil obtained by this method has great industrial value, as it does not shift or come off even when tension is applied during the manufacturing process of sheathed heaters.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional coil with a terminal, Fig. 2 is a sectional view of the coil with a terminal in an expanded state, and Fig. 3 is a sectional view of a coil with a terminal showing an embodiment of the present invention. FIG. 4 is a sectional view of the terminal-equipped coil in one manufacturing process. 11... Coil, 12... Terminal, 13
...Metal tube.

Claims (1)

[Claims] 1. An end of a heating wire coil is placed around the outer periphery of the end of a round bar-shaped terminal, and the end of the heating wire coil is covered with a metal tube having a spiral groove on the inner surface, and the terminal and a heating wire coil with a terminal, the end portion of the heating wire coil being clamped and fixed by the metal tube. 2. Align the end of the heating wire coil along the spiral groove provided on the inner surface of the metal tube, then press fit a round bar-shaped terminal with a tapered tip into the end of the heating wire coil, and A method for manufacturing a heating wire coil with a terminal, comprising: clamping and fixing an end portion of the heating wire coil with the metal tube.