Projection soldering structure of power head part for thermal expansion valve

Abstract

The invention relates to a convex brazing structure of dynamic head component of thermal expansion valve. The dynamic head component is consists of a stopper and a cavity which used to accommodate the thermal-sensitive medium. The cavity has holes in its ektexine and the medium can be added into the cavity through the holes. The stopper is used to plug the holes so the medium is sealed in the cavity. Its characteristics are implementing convex brazing between the stopper and the holes to form the first part of welding line, placing brazing filler metal between the stopper and the ektexine and brazing to form the second part of welding line. The welding field is formed in one time, and at the time of the completion of the first part of seal, the solder is prevented from flowing into the cavity when the brazing filler metal is melted. The seal and the antisepsis are mainly realized by the brazing.

Description

【Technical field】 [0001] The invention relates to a thermal expansion valve suitable for an air-conditioning system, especially a structure for sealing a heat-sensitive medium in an accommodating cavity by sealing a filling hole of a power head (also called an air box head) with a plug. 【Background technique】 [0002] The existing thermal expansion valve suitable for air-conditioning systems is clearly recorded in the invention patent specification with the notification number CN 1058779C. The structure in the cavity is described in detail, and the analysis and induction of the prior art in this document are as follows: ①Project welding is performed between the edge around the hole and the conical surface of the plug, because a concave part is formed around the convex welding part, so Water accumulation (condensation water, etc.) is likely to occur in the concave part, and there is a problem of corroding the outer wall of the cover; ② The plug is tack welded by projection we...

AI Technical Summary

Problems solved by technology

However, since the projection welding is directly connected together by melting the contact parts of two connected parts through resistance heat, the smaller the contact area of ​​the two parts, the greater the resistance heat generated per unit area, and the better the welding effect. The opposite is the opposite; therefore, the above solution sacrifices the welding quality per unit area while achieving multiple welding positions, which is undesirable to seal the heat-sensitive medium in the containing chamber with a plug, unless the welding energy is increased ; Moreover, the "cavity" pointed out in the CN 1058779C No. invention patent description will be formed between multiple welding positions to cause internal corrosion problems

[0004] On a deeper level, due to the heat expansion of the sealed heat-sensitive medium during welding, the pressure increases, which is very unfavorable for the relatively small welding part (0.2-1.5mm) formed by projection welding; based on the characteristics of projection welding, It is unavoidable to form a concave part around the convex welding part, so in order to prevent the outer wall from corrosion, it is difficult to realize it in one process by covering the surrounding of the convex welding part with anti-corrosion material

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