JPH10206053A - Tubes for heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of the joining parts of corrugated inner fins and flat tubes being unit formed with a band form metal plate. SOLUTION: This tube is formed by folding back a band form metal plate with the bending of a half circle at the end edge 1a of a trapezoidal wave part 1 and the flat outer peripheral part 2 is formed by folding back it at the start edge of the trapezoidal wave part 1 with the bending of a half circle. A rising wall part 3 being bent to L shape conforming to the inner surface 1aa of the rising part of the trapezoidal wave part 1 is formed at the edge of the flat outer peripheral part 2 and a curled edge part 4 is formed at the top of the rising wall part 3. The surface of the wall part 3 is elastically contacted to the inner surface 1aa of the rising part of the wave opposing the spring back of each bending part and each of the contacting parts are fixed as a unit by blazing or soldering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat tube for a heat exchanger having inner fins, wherein an inner fin portion and a flat tube portion are integrally formed of a band-shaped metal plate.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 52-49859 discloses a tube with an inner fin and a method of manufacturing the tube. The inner fin is formed by integrally connecting inner fins extending inward from the butt portion of a tube formed by winding a band-shaped metal plate and butting the tube. The manufacturing method is as follows. That is, first, a corrugation along the longitudinal direction is formed at a key point on one side edge of the band-shaped metal plate. Next, the corrugated end of the metal plate is bent inward, and the remaining portion of the metal plate is circularly wound to form a tube. Then, the other side edge of the metal plate is brought into contact with the start end of the wave bent portion. Next, the contact portions are joined and adhered to each other, the outer surfaces of both sides of the wave bent portion of the tube are pressed to form a flat tube, and the inner surface of the tube is pressed against the top of the wave bent portion.

[0003]

The conventional flat tube with inner fins has an inner fin portion integrally inside, so that it is difficult to improve the accuracy of the tube butt portion on the outer periphery thereof, and the butt joint portion is difficult. Had a disadvantage that it lacked reliability. Then, this invention makes it a subject to provide the tube for heat exchangers whose butt part has high reliability.

[0004]

SUMMARY OF THE INVENTION A heat exchanger tube according to the present invention comprises a trapezoidal wave portion 1 whose ridge line is located in the longitudinal direction of the tube and is formed in a trapezoidal wave shape, and a terminal 1a of the trapezoidal wave portion 1. The trapezoidal wave portion 1 is folded back and bent in a substantially semicircular shape, and the starting end 1b of the trapezoidal wave portion 1 is folded back in a substantially semicircular shape so as to surround the entire trapezoidal wave portion 1 and contact the tops and valley outer surfaces of the waves. A bent flat outer peripheral portion 2, a rising wall portion 3 whose distal end of the flat outer peripheral portion 2 is bent into an acute L-shape in a tube, and the above-mentioned L on the top of the rising wall portion 3.
A tip curl portion 4 bent at an obtuse angle to the inner corner side of the character is integrally formed with a band-shaped metal plate, and the entire rising wall portion 3 is an inner surface of a rising portion of a wave at the end 1 a of the trapezoidal wave portion 1. 1aa, and the rising wall 3 has a resilient action due to the bending thereof, and against the resilient force, raises the rising wall 3 to the rising portion of the wave. In a state where the inner surface 1aa is resiliently pressed and the tip curl portion 4 is slightly separated from the rising portion inner surface 1aa, the contact portions are integrally brazed or soldered and fixed. .

[0005]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 is a schematic cross-sectional view of a tube for a heat exchanger of the present invention, FIG. 2 is an explanatory view showing a manufacturing process thereof, FIG. 3 is an enlarged view of a main part of FIG. 1, and FIG. FIG. 2 is an enlarged cross-sectional view of a strip-shaped metal plate used for the present invention. This heat exchanger tube is formed by integrally bending a strip-shaped metal plate and forming an inner fin including a trapezoidal wave portion 1 as a continuous body of the flat outer peripheral portion 2 inside. In this example, as shown in FIG. 4, a band-shaped metal plate having a brazing material 7 clad on both sides of a core material 6 is used. And the trapezoidal wave part 1 bent in trapezoidal wave shape is formed in the strip-shaped metal plate so that a ridgeline may be located in the longitudinal direction of a tube.
Next, the trapezoidal wave portion 1 is folded back and bent in a substantially semicircular shape from the terminal end 1a so that the diameter matches the amplitude of the trapezoidal wave portion 1. Then, the trapezoidal wave portion 1 is similarly bent in a semicircular shape at the start end 1b so as to surround the entire trapezoidal wave portion 1 and bend so as to come into contact with the tops and valley outer surfaces of the wave.
Is configured.

Further, a rising wall portion 3 is formed in the tube in which the tip of the flat outer peripheral portion 2 is bent into an acute L-shape. Further, a tip curl portion 4 bent at an obtuse angle toward the inner angle side of the L-shape is formed on the top of the rising wall portion 3. The entire rising wall portion 3 is the end 1 a of the trapezoidal wave portion 1.
So as to elastically match the inner surface 1aa of the rising portion of
Determine its angle and position. By bending the strip-shaped metal plate in this manner and forming at least a semicircular folded portion 2b at the start end 1b, the tip of the flat outer peripheral portion 2 is separated from the valley of the trapezoidal wave portion 1 by a spring as shown in FIG. Will be back. Therefore, against the springback action, the rising wall 3 is pressed from the solid line state to the dashed line state in FIG. 2 so that the rising wall section 3 and the rising section inner surface 1aa are elastically brought into surface contact. At this time, the rising portion inner surface 1aa has a sufficient rigidity, and the rising wall portion 3 is formed in an L-shape, so that the rising wall portion 3 is elastically deformed, and the two planes are in close contact with each other. At this time, the tip curl portion 4 is slightly separated from the surface of the rising portion inner surface 1aa, and the tip curl portion 4 forms a rigid portion. Then, the adhesiveness between the rising wall 3 and the inner surface 1aa of the rising portion is improved.

As described above, the entire tube is heated while the rising wall portion 3 is elastically pressed against the inner surface 1aa of the rising portion, and the brazing material on the surface is melted to form the rising wall portion 3 and the rising portion. As shown in FIG. 3, the inner surface 1aa and the inner surface 1aa are integrally brazed and fixed, and the outer surfaces of the ridges and valleys of each trapezoidal wave portion 1 and the inner surface of the flat outer peripheral portion 2 are fixed by brazing. This completes the dexterity tube.

[0008]

Operation and effect of the present invention The heat exchanger tube of the present invention
The rising wall 3 is the inner surface 1aa of the rising portion of the trapezoidal wave portion 1.
Are formed so as to be aligned with each other, and both are resiliently pressed to make surface contact using the elastic force of the tube material itself. At this time, the front end curl portion 4 forms a rigid portion at the front end of the rising wall portion 3 to form the surface contact uniformly. The tip curl portion 4 is one in which the contact portions are integrally brazed or soldered while being slightly separated from the inner surface 1aa of the rising portion. Therefore, reliable brazing or soldering is ensured. And a reliable heat exchanger tube without leakage can be provided. In addition, the tip curl portion 4 at the tip of the rising wall portion 3 is formed on the inner surface 1aa of the rising portion.
, It is possible to secure a long contact surface between the rising wall 3 and the inner surface 1aa of the rising portion without relatively high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a heat exchanger tube of the present invention.

FIG. 2 is an explanatory view showing a manufacturing process of the heat exchanger tube.

FIG. 3 is an enlarged view of a main part of FIG. 1;

FIG. 4 is an enlarged cross-sectional view of a strip-shaped metal plate used for manufacturing the heat exchanger tube.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 trapezoidal wave portion 1 a end 1 aa rising portion inner surface 1 b starting end 2 flat outer peripheral portion 2 a, 2 b folded portion 3 rising wall portion 4 tip curl portion 5 brazing filler fillet 6 core material 7 brazing material

Claims (2)

[Claims] 1. A trapezoidal wave portion 1 whose ridge line is located in the longitudinal direction of a tube and is formed in a trapezoidal wave shape. The trapezoidal wave portion 1 is folded back and bent in a substantially semicircular shape from an end 1a of the tube. A flat outer peripheral portion 2 which is formed by bending the start end 1b of the portion 1 into a substantially semicircular shape, surrounding the entire trapezoidal wave portion 1 and bending so as to come into contact with the tops and valley outer surfaces of the waves; A rising wall portion 3 whose tip is bent into an L-shape at an acute angle in the tube, and a tip curl portion 4 bent at an obtuse angle on the inner angle side of the L-shape at the top of the rising wall portion 3 , And are integrally formed of a band-shaped metal plate, and the entire rising wall 3 is the end 1 of the trapezoidal wave portion 1.
The rising wall portion 3 is formed in alignment with the inner surface 1aa of the rising portion of the wave a, and the rising wall portion 3 has a resilient action due to the bending thereof, and the rising wall portion 3 has a resilient force. 3 is resiliently pressed against the inner surface 1aa of the rising portion of the wave to make surface contact therewith, and while the tip curl portion 4 is slightly separated from the inner surface 1aa of the rising portion, the contact portions are integrally brazed or soldered. A heat exchanger tube characterized by being attached and fixed. 2. The heat-manufactured product according to claim 1, wherein the band-shaped metal plate is formed by cladding a brazing material 7 on both sides of a core material 6, melting the brazing material 7 and then solidifying the same. Tube for exchanger.