JPH0113357Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a sheathed heater equipped with a welded metal fitting joined by plasma welding.

Conventional structure and problems Conventionally, spot welding has been used to weld the terminals of this type of sheathed heater, but with this method, the sealing of the sheathed heater is caused by mechanical impact from above during welding. Loads were applied to the parts, which could easily cause the glass sealing material to crack, causing insulation deterioration. As shown in FIG. 1, a welding fitting 3 is spot-welded to a terminal 2 that constitutes a part of a sheathed heater 1, and the end of a lead wire 6 is fastened with a fitting 5, and then a round screw 4 is attached to the terminal 2. The conventional configuration was one in which the welding fitting 3 was screwed into the screw hole 7. Here, the method of spot welding the terminal 2 and the welding fitting 3 in FIG. 1 will be explained in detail in FIG. 2.
The tip of the terminal 2 is placed against the side surface 8 on the terminal side of the punched hole of the welding fitting 3, and spot welding is performed with the terminal 2 in contact with the projection 9.
The contact part is melted and joined. However, at this time, a mechanical shock is applied to the terminal 2, and the shock is also transmitted to the sealing part of the sheathed heater.
The glass sealing material could crack, which could easily cause insulation deterioration. In contrast to these welding methods, plasma welding, which can melt the contact area by blowing an arc without applying mechanical impact, is well known, but this conventional metal fittings require plasma welding. It is difficult and unstable to control the position, and in projection, the arc is difficult to fly, resulting in a lack of welding strength.

Purpose of the invention The present invention was made to solve the above-mentioned conventional problems, and its object is to provide a sheathed heater that can firmly and accurately weld a welding fitting to a terminal.

Structure of the Invention In order to achieve the above object, the sheathed heater of the present invention has a welding metal fitting provided with a protrusion facing the terminal tip and slits provided on both sides of the protrusion. By plasma welding the terminal, the welding fitting can be accurately positioned and firmly attached to the terminal of the sheathed heater.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 to 5.

In FIG. 3, members that are the same as those in the prior art are given the same reference numerals and their explanations will be omitted. 10 is a welding metal fitting 11
This is a protruding part formed by cutting and raising the flesh of the protruding part upward, and slit parts 12 are punched out on both sides of the protruding part. 13 is a punched hole provided to facilitate plasma welding by providing this protrusion 10; 14 is a recess provided along the central axis of the welding fitting 11; contact along the recess 14, the tip of the terminal 2 stops against the tip side surface 15 of the protrusion 10, and at the same time an arc is ejected to this contact portion to perform welding. Reference numeral 16 denotes a screw hole into which a lead wire or the like for wiring is screwed. As shown in FIG. 5, the terminal 2 coming out from the sheathed heater 1 is
The plasma-welded contact area 17 on the side surface of the tip of the protrusion 10 is melted and joined.
At this time, since the slit part 12 is provided, the heat of the welding part is not conducted to the entire welding fitting 11, and the heat of the welding part is not conducted to the terminal 2.
A good heat balance can be obtained and reliable plasma welding can be performed.

In this way, in this embodiment, the side surface of the terminal 2 is formed into a recess 1.
4 and the tip of the terminal 2 is brought into contact with the tip side surface 15 of the protrusion 10, so that the welding fitting 11 can be accurately and firmly welded to the terminal 2. Further, since the welding fitting 11 has the recess 14 and the protrusion 10 connected to the punched hole 13 through the slit 12, the recess 14 can be easily formed, and the welding fitting 11 as a whole can be easily formed. Further, when the width S of the slit portion 12 is within the range of tS2t, where t is the thickness of the welding fitting 11, welding strength is large and efficient.

In the above embodiment, the tip of the terminal 2 is brought into contact with the tip side surface 15 of the protrusion 10 and plasma welded between them. Even if the tip of the terminal 2 is brought into contact with the rising side surface of the terminal 2 and the two are plasma welded, the same effects as in the above embodiment can be obtained.

Effects of the Invention As is clear from the above embodiments, the sheathed heater of the present invention enables plasma welding that improves the performance and quality of the main body, and can maintain constant welding strength. Further, by providing the slit portions on both sides of the protruding portion, the efficiency of plasma welding can be increased.

[Brief explanation of drawings]

FIG. 1a is a plan view showing the connection state of a conventional sheathed heater, FIG. 1b is a side view of the same, FIG. 2 is a perspective view of the same welding fittings, and FIG. FIG. 4 is an enlarged perspective view of the slit portion, and FIG. 5 is a perspective view of the sheathed heater. 2...Terminal, 10...Protrusion part, 11...Welding fitting, 12...Slit part.

Claims (1)

[Claims for Utility Model Registration] (1) A welding fitting having a protrusion facing the tip of the terminal and slits provided on both sides of the protrusion is plasma welded to the terminal on the surface of the protrusion. A sheathed heater. (2) The sheathed heater according to claim 1, wherein the width S of the slit portion is tS2t with respect to the thickness t of the welding fitting.