JPH0212683Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to airtight terminals, and is particularly suitable for airtight terminals that are resistance welded to compressor cases for various types of cold machines, such as electric refrigerators, room coolers, and ice cream stockers. It is something to do.

Conventional technology In various types of cold devices such as refrigerators, room coolers, and ice cream stockers, refrigerant is compressed and liquefied and guided to an evaporator, where the evaporator removes heat from the high-temperature gas and vaporizes it, and the vaporized refrigerant is recycled again. It is cooled by a refrigeration cycle that compresses and liquefies it.

In such a cold compressor, the compression motor is housed in a sealed container, and the electrical terminals are taken out to the outside using airtight terminals.

FIG. 6 is a plan view of an airtight terminal a for a cold machine disclosed in, for example, Japanese Utility Model Publication No. 57-48064, and FIG. 7 is a sectional view taken along the line - in FIG. 6. In the figure, 1 is a metal outer ring manufactured by press-molding a plate made of iron or low carbon steel, and includes a top plate part 2, an annular part 3, and a tapered shape extending obliquely downward and outward from the lower end of the annular part 3. It has a flange portion 4 , and a plurality of (in the illustrated example, three) cylindrical portions 5 serving as through holes for glass sealing, which face inward from the top plate portion 2 . Reference numeral 6 denotes a glass such as soda barium glass or soda lime glass that is fused in each of the cylindrical parts 5, and a lead wire 7 made of iron/chromium alloy or copper core iron/chromium alloy clad is connected through the glass 6. is sealed in an airtight and insulating manner. 8 is a terminal plate welded to both ends of each lead wire 7. In order to prevent dew condensation on the upper surface of the top plate 2, silicone rubber 9 may be applied to the upper surface of the top plate 2 and along the lead wires 7, as shown by the two-dot chain line in the figure.

The above airtight terminal a is connected to a compressor case 10 consisting of a cover 11 and a main body 12 as shown in FIG.
It is used by being welded to the cover 11 of. That is,
As is clear from the enlarged cross-sectional view of the main part in FIG. By bringing a line into contact with the lower end 11b of the through hole 11a and passing a concentrated current through the line contact portion, so-called projection welding is performed to secure the wire.

Problems to be Solved by the Invention However, even if the airtight terminal a alone has extremely high airtightness, airtightness failures may occur during leak tests and pressure tests after welding the cover 11. However, the cause was unknown.

The inventors thoroughly investigated the cause of this deterioration of airtightness during welding and found the following. That is, the outer surface of the flange portion 4 is pressed by the load applied to the welding electrode during welding, and therefore stress is applied to the flange portion 4 in the X direction in FIG. The top plate portion 2 is deformed as shown by the chain line, and accordingly, the top plate portion 2 receives stress in the Y direction in the figure based on the principle of a lever, and bulges upward as shown by the two-dot chain line in the figure. On the other hand, the through hole 1 of the cover 11
When the airtight terminal a is inserted into the through hole 11a
A slight gap is formed between the inner surface of the airtight terminal a and the outer surface of the annular portion 3 of the airtight terminal a. However, the meat 13 that has softened and flowed at the lower end 11b of the through hole 11a of the cover 11 during welding fills the gap, as shown in FIG. Therefore, the heat of the meat 13 filled in the gap is conducted to the glass 6 via the annular portion 3 and the top plate portion 2. As a result, as shown in FIG. 11, due to the synergistic effect of the mechanical stress and thermal shock, cracks occur in the glass 6 from the sealing interface A between the top plate 2 and the glass 6, causing airtightness to deteriorate. It is.

The deformation caused by the mechanical stress can be solved, for example, by increasing the inner thickness of the metal outer ring 1. However, doing so not only increases material costs, but also requires a large load for press forming, making conventional presses unusable. Moreover, with respect to thermal shock, the thicker the metal outer ring 1 is, the smaller the thermal resistance of the flange part 4 and the annular part 3 becomes.
You will encounter new problems that will make you increasingly disadvantaged.

Means for solving the problem This idea is based on the following knowledge. Connect the airtight terminal a to the through hole 11a of the compressor case 11.
When fitted, the flange portion 4 of the airtight terminal a and the lower end 11b of the through hole 11a are in line contact as described above, but when current is applied to this line contact portion, the lower end of the through hole 11a 11b is melted and welded to the flange portion 4. At this time, the through hole 11a
As the lower end 11b melts and softens and flows, the meat spreads toward the outer end of the flange portion 4, so that at the end of welding, the compressor case 11 is positioned further outside the flange portion 4 than at the initial line contact position. Welded to a position close to the edge. Therefore, in order to simply prevent thermal shock caused by the softened and fluid meat, the through hole 1 of the compressor case 11 is
If the inner diameter D of 1a is made too large, the welding position is likely to deviate from the flange portion 4, resulting in poor welding. Moreover, if the inner diameter D of the through hole 11a of the compressor case 11 becomes larger than the outer diameter d of the airtight terminal a, the gap between the two becomes larger.
It becomes difficult to position it concentrically with the through hole 11a, and it becomes easy to position it eccentrically or at an angle, making welding defects more likely to occur.

Considering the above contradictory points, the airtight terminal a
The outer diameter d of the through hole 11a of the compressor case 11 and the inner diameter D of the through hole 11a are defined as the lower end 11b of the through hole 11a and the flange portion 4.
It has been found that the best welding results can be obtained when the line contact position with the annular part 3 and the flange part 4 is set to be approximately 1/3 of the total length of the flange part 4 from the boundary line between the annular part 3 and the flange part 4.

Therefore, in this invention, the lower end 11 of the through hole 11a
This relates to an airtight terminal for resistance welding under the condition that the line contact position between b and the flange part 4 is approximately 1/3 of the total length of the flange part 4 from the boundary line with the annular part 3. The flange is characterized in that a thin wall portion is formed in a portion approximately 1/3 of the total length of the flange portion from the boundary line with the annular portion of the flange portion.

Effect: According to the above configuration, the airtight terminal can be optimally positioned with respect to the through hole of the object to be welded, such as a compressor case, by using the boundary line between the thin wall portion and the thick wall portion. . Further, even if mechanical stress is applied to the flange portion during resistance welding, this stress is absorbed and alleviated by the thin wall portion, thereby preventing deformation of the top plate portion. Furthermore, heat during resistance welding is difficult to conduct to the annular portion due to the thermal resistance of the thin wall portion, and no thermal shock is applied to the glass. In this way, it is possible to prevent cracks from occurring in the glass during resistance welding of the airtight terminal, thereby preventing airtightness from deteriorating.

Embodiment FIG. 2 shows a plan view of an airtight terminal b according to an embodiment of this invention, and FIG. 1 shows a sectional view taken along the line - in FIG. In the figure, except for the following points, the sixth
5 and 5, the same parts are given the same reference numerals and the explanation thereof will be omitted. The difference between FIG. 6 and FIG. 5 is that there is a thin-walled portion in the range of approximately 1/3 of the total length L of the flange portion 4 from the boundary line 14 between the outer surface of the flange portion 4 and the annular portion 3. 15.

According to the above configuration, as shown in FIG.
The line contact position between the flange portion 4 and the flange portion 4 is
If the length l from the boundary line 14 with the annular part 3 is set to be approximately L/3 with respect to the total length L of It can be positioned coaxially with the through hole 11c. Moreover, even if the heat during welding attempts to be conducted to the annular portion 3, it will not only be difficult to conduct due to the thermal resistance of the thin walled portion 15, but also between the airtight terminal b and the through hole 11.
Since the gap formed between glass 6 and c is larger than before, the softened and fluidized meat at the lower end 11d of the through hole 11c does not fill the gap, and no thermal shock is applied to the glass 6. Furthermore, the mechanical stress applied to the flange portion 4 during welding is absorbed and relaxed by the thin wall portion 15, so that no excessive mechanical stress is applied to the glass 6. For this reason,
The generation of cracks in the glass 6 can be prevented, and deterioration of airtightness can be prevented.

FIG. 4 shows a plan view of an airtight terminal c according to another embodiment of the invention, and FIG. 5 shows a sectional view taken along the line - in FIG. 4. The difference between this embodiment and the previous embodiment is that a cross section is formed at a position approximately 1/3 of the total length L of the flange portion 4 from the boundary line 14 between the outer surface of the flange portion 4 and the annular portion 3. The thin wall portion 16 is formed by forming a V-shaped groove. It will be easily understood that the same effects as in the previous embodiment can be obtained in this embodiment as well.

In the first and second embodiments described above, it is of course possible to apply silicone rubber 9 to the upper surface of the top plate portion 2 as shown by the two-dot chain line.

Effects of the invention As described above, this invention not only makes it possible to accurately position the airtight terminal on an object such as a compressor case by using the thin part formed in the flange part, but also provides resistance by using the thin part. Heat conduction during welding is suppressed, mechanical stress is absorbed and relaxed, and thermal shock and mechanical stress no longer act on the glass, preventing cracks from occurring in the glass and preventing airtightness from deteriorating. obtain.

[Brief explanation of the drawing]

Fig. 2 is a plan view of the airtight terminal according to the first embodiment of this invention, Fig. 1 is a sectional view taken along the - line in Fig. 2, and Fig. 3 is an assembled state of the airtight terminal before welding. FIG. 2 is a cross-sectional view showing a main part enlarged in a circle. FIG. 4 is a plan view of a second embodiment of the airtight terminal of this invention, and FIG. 5 is a sectional view taken along the line - in FIG. 4. Figure 6 is a plan view of a conventional airtight terminal;
The figure is a sectional view taken along the - line in FIG. 6. 8th
The figure is a front view of a compressor case with resistance welded airtight terminals, Fig. 9 is an enlarged cross-sectional view of main parts in the assembled state before resistance welding, and Fig. 10 is a cross-sectional view to explain the drawbacks of conventional airtight terminals. FIG. 11 is an enlarged sectional view of the main part of FIG. 10. b, c...Hermetic terminal, 1...Metal outer ring, 2...
Top plate part, 3... Annular part, 4... Flange part, 5...
...Through hole for glass sealing (cylindrical part), 6...Glass,
7...Lead wire, 11c...Through hole in compressor case, 14...Boundary line between annular part and flange part, 1
5, 16... Thin wall portion.

Claims (1)

[Claims for Utility Model Registration] A metal outer ring having a top plate portion, an annular portion, a tapered flange portion, and a glass sealing through hole formed in the top plate portion; and a lead wire sealed in an airtight and insulated manner, the airtight terminal being resistance welded to the outer surface of the flange portion with the lower end edge of the through hole of the attached body in line contact with the outer surface of the flange portion. Dimension l from the annular part of
An airtight terminal characterized in that a thin wall portion is formed at a location approximately L/3 of the total length L of the flange portion.