JPS60155661A - Method for plating solder to metallic pipe - Google Patents

Abstract

PURPOSE:To prevent remaining of solder as a flash at the end of a metallic pipe by dipping the metallic pipe into the molten solder to plate the solder thereon and pulling upward the pipe from the molten solder then passing air into the metallic pipe and blowing off the air from the end of the pipe. CONSTITUTION:The end of an Al pipe 2 is dipped into the molten solder in a solder bath vessel 4 provided with a heater 3 and an ultrasonic wave is impressed to the solder by an ultrasonic oscillator 5 and an oscillating diaphragm 6 to form a uniform plating layer to the pipe 2. The pipe 2 is thereafter pulled upward from the molten solder and a large amt. of air is supplied from an air compressor 11 via a reducing valve 10, solenoid valve 9 and a joint 13, etc. into the pipe 2 and is blown off from the end. The solder sagging from the end is thus blown off and is prevented from solidifying to form a flash.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of solder plating a metal tube by immersing it in molten solder.

[Technical background of the invention]

For example, when fitting metal tubes together and joining them with solder, solder is applied to the inner and outer surfaces of both metal tubes in a pre-process. This solder attachment is generally performed by dipping the metal tube into molten solder and plating it with solder.

[Problems with back-feeding technology]

However, in the above-mentioned solder joining method, when the metal tube is pulled up from the molten solder, the solder hangs down from the bottom end of the metal tube and is rapidly cooled. There was a problem in that this hindered bonding.

(Object of the Invention) The present invention has been made in view of the above-mentioned circumstances, and its object is to provide a method for solder plating a metal tube in which solder does not remain in the form of flakes at the end of the metal tube.

[Summary of defense]

In the present invention, after the metal tube is pulled up from molten solder, air is passed through the metal tube and blown out from the end of the metal tube, and the solder hanging down from the end of the metal tube is blown away by the air.

[Embodiments of the invention]

An embodiment of the present invention will be described below based on the drawings.

This example is an ultrasonic solder plating device that applies numbered plating to the ends of the steel pipes and the refrigerant pipes of an aluminum cooler when they are fitted and joined by solder in the piping of a refrigeration cycle. It was applied to

First, FIGS. 1 and 2 show a copper tube 1 and an aluminum tube 2 (refrigerant tubes of a cooler) that are connected to each other. This copper pipe 1
The tip is tapered so that the diameter gradually decreases. On the other hand, the end of the aluminum tube 2 is expanded in diameter, and the tip of the expanded diameter portion 2a is expanded into a tapered shape so that the diameter gradually increases (X).In this case, the inner diameter dimension At of the expanded diameter portion 2a is The outer diameter dimension B of the copper tube 1 is set to be equal to or slightly smaller than this, and in this embodiment, the outer diameter dimension is set to be about 0.05 to 0.11 smaller than the B1 method.

This is because the aluminum tube 2 is eroded by the ultrasonic wave when the so-called ultrasonic wave, which will be described later, is applied to the inner peripheral surface of the aluminum tube 2 by the ultrasonic wave.
5 to 0.1m'm) and set it smaller accordingly.
It's a small thing. Moreover, the length dimension C of the enlarged diameter portion 2a is the same as that of the copper pipe 1.
The fitting length D (see FIG. 9) is set to be slightly shorter than the fitting length D (see FIG. 9) when the aluminum tube 2 and the aluminum tube 2 are fitted as described below.

Next, FIGS. 3 and 4 show an ultrasonic soldering device for attaching solder to a copper tube 1 and an aluminum tube 2, respectively. A diaphragm 6 connected to the sonic vibrator 5 is provided. Also, the copper tube 1 immersed in the molten solder 7 in the bath 4 . The aluminum pipes 2 are connected to joints 12, 13 which are connected to the air compressor 11 via solenoid valves 8, 9 and pressure reducing valves 10, 10, respectively. On the copper pipe 1 side, a pressure reducing valve 14 is connected in parallel with the solenoid valve 8. A bypass conduit 17 is provided in which a flow control valve 15 and a solenoid valve 16 are connected in series. Also, among the pipes on the aluminum pipe 2 side, the pipe 18 between the joint 13 and the solenoid valve 9 is connected to the solenoid valve 9.
When the power is cut off, the boat 9a is opened to the atmosphere. By the way, the solder 7 is Z, 1
Use 95% aluminum solder and 15% A solder, and the heating temperature of the solder 7 on the copper tube 1 side is approximately 415°C.

The temperature is adjusted to maintain approximately 440°C on the aluminum tube 2 side. Therefore, Fig. 5 shows the pipe connection device,
A pressure jig 20 for holding the copper tube 1 is provided above the holder 19 for holding the aluminum tube 2 so as to be movable up and down, and an ultrasonic vibrator 21 is further provided above the pressure jig 20. . Further, between the holder 19 and the pressurizing jig 20, a plurality of gas burners 22 and 23 for heating the ends of the copper tube 1 and the aluminum tube 2 are arranged in two upper and lower stages.

Next, the procedure for connecting the copper tube 1 and the aluminum tube 2 will be explained. To do this, first, at the ends of both pipes 1 and 2, /V
This involves connecting the copper pipe 1 and the aluminum pipe 2 to the joints 12 and 13, respectively, and then energizing the solenoid valve 16 to connect the other solenoid valves 8,
This is done by immersing the ends of both tubes 1 and 2 in molten solder 7, as shown in FIGS. . Then, the pressure reducing valve 14 is inserted into the copper pipe 1 through the bypass pipe line 17.
Since low-pressure compressed air is supplied, the internal pressure of the copper tube 1 will not increase and the molten solder 7 will not infiltrate into the interior of the copper tube 1. On the other hand, the air inside the aluminum tube 2 passes through the tube 18 to the solenoid valve 9. In order to escape from the tube 1-98 into the atmosphere, the melted (read 7)
As a result, the molten solder 7 penetrates into the inside of the copper tube 1, and the molten solder 7 ends up on the outer peripheral surface of the end of the copper tube 1. However, as for the aluminum tube 2, the molten solder 7 adheres to both inner peripheral surfaces A of the end portion. At this time, the vibration plate 6 is attached to the molten solder 7.
Ultrasonic waves (approximately 18 Kl-IZ) are recorded by this method! As a result, so-called cavitation occurs and countless small vacuum nuclei are generated in the molten solder 7, and when these nuclei disappear, the instantaneous force removes dirt and oxide films on the surfaces of the copper tube 1 and aluminum tube 2. In addition to forming a uniform plating layer, the ultrasonic waves increase the fluidity of the molten II ('li) solder 7, promoting wetting and improving plating properties.

After this immersion, both pipes 1 and 2 are pulled up from the molten solder 7, and immediately after this pulling up, the solenoid valve 8.
energize.

Then, a large amount of compressed air is supplied into both pipes 1.2 through the solenoid valve 8°9, and the air is supplied to the copper pipes 1.2. It flows through the aluminum tube 2 and blows out from its end. As a result, the solder hanging down like "drops" from the ends of both tubes 1 and 2 is blown away by the compressed air, and the solder is prevented from solidifying into "drops" and remaining as flakes. In addition, in order to secure the solder necessary for joining, the copper tube 1 is dipped into the molten solder 7 described above once again (the second immersion depth is slightly shallower than the first time). Regarding the aluminum tube 2, it is preferable to perform the above-mentioned air blowing twice in order to equalize the thickness of solder adhesion on the inner circumferential surface.

Now, as described above, the thin solder layers 24 and 2 are applied to the ends.
As shown in FIG. 5, the copper tube 1 and the aluminum tube 2 to which No. 5 is attached are held in a pressure jig 20 and a boulder 19, respectively, so as to face each other vertically, and then the pressure jig 20 is lowered to form the sixth As shown in the figure, the lower end of the copper tube 1 is butted against the upper end of the aluminum tube 2 with a weak pressure. Next, in this abutted state, the ends of both tubes 1 and 2 are heated by gas burners 22 and 23 as shown in FIG.
5 is melted. Note that if the pressure applied to the copper tR1 at this time is too large, the copper tube 1 will be pushed into the aluminum tube 2 when one of the solder layers 24 or 25 is melted, and a good bonding state will not be obtained. The pressure is extremely weak, but it's still bothering me. Then, both solder layers 24
When the copper tube 1 and 25 are melted, the pressure jig 20 is used to press down the copper tube 1 with strong pressure while driving the ultrasonic vibrator 21. Fit it inside the end of 2. At this time, the pressing distance of the copper tube 1 is slightly larger than the length C of the enlarged diameter part 2a of the aluminum tube 2. 2 by pushing out the lower part of the enlarged diameter part 2a.

The expansion of the diameter of the aluminum tube 2 by the copper tube 1 brings the two tubes 1 and 2 into strong contact. Even if the aluminum tube 2 is eroded during ultrasonic solder plating, the tubes 1 and 2 are tightly fitted with an extremely small clearance, so that the ultrasonic wave is not applied from the ultrasonic vibrator 21 to the copper tube 1. The ultrasonic vibrations are effectively transmitted to the aluminum tube 2, and this ultrasonic vibration increases the wettability of the molten solder on both solder layers 24 and 25.
The entire clearance between both tubes 1 and 2 is completely filled. After this, application of ultrasonic vibration and gas burner 24, 25
The heating is stopped, and the solder is allowed to cool naturally to solidify, thereby joining the copper tube 1 and the aluminum tube 2 as shown in FIG.

〔Effect of the invention〕

As explained above, in the present invention, after the metal tube is pulled up from the molten solder, air is passed through the metal tube and blown out from the end thereof, so that the solder hanging down from the end of the metal tube is not blown away by the air. This has an excellent effect in that there is no risk of the solder becoming flaky and remaining.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a front view of a steel pipe and an aluminum pipe, Fig. 2 is an enlarged longitudinal cross-sectional view of the same end, and Figs. 3 and 4 are ultrasonic waves. FIG. 5 is a vertical cross-sectional view of the pipe connecting device, and FIGS. 6 to 9 are vertical cross-sectional views sequentially showing the connection process. In the figure, 1 is a steel pipe, 2 is an aluminum pipe, 4 is a solder bath, 5 is an ultrasonic vibrator, 7 is molten solder, and 11 is a near compressor. Applicant Tokyo Shibaura Electric Co., Ltd. No. 1 No. 2 Fig. 3 Fig. 4 5 times 11/- No. 7 M Fig. 9

Claims (1)

[Claims] 1. In the method of solder plating by immersing a metal tube in a molten solder, after pulling the metal tube out of the molten solder,
A method for solder plating a metal tube, characterized in that air is passed through the metal tube and blown out from the end thereof.