JPH0420791A - Heat exchange tube and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture a tube with the height thereof being ultra-thin structure by allowing a bent protrusion part as a reinforcing member by providing the bent protrusion part so as to protrude from a planar wall part facing vertically to an electric pipe and joinning and integrating the bent protrusion parts such that the top end of the bent protrusion part makes contact with a partition partner plane wall inner surface or with the top end of an opposite bent protrusion part. CONSTITUTION:A heat exchange tube 1 comprises a flattened oblique cross section electric tube in which upper and lower planar wall parts 2, 3 facing to each other spaced mutually by 0.8mm for example are continuously connected at their one ends via a V-shaped bent part 4, and they are welded 5 in an abutment at the other ends thereof. There are inwardly protruded bent protrusion parts of every two of the same such that they are alternately disposed widthwise of the tube 1. The bent protrusion parts 6 are brought into contact with the internal surfaces of partner plane wall parts at the top ends thereof, and are integrally joinned with the internal surfaces by brazing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to tubes for heat exchangers, particularly flat tubes used in multi-flow heat exchangers used as condensers for car coolers, and a method for manufacturing the same. .

BACKGROUND OF THE INVENTION Conventionally, a serpentine tube type heat exchanger has generally been used in a car cooler condenser. That is, a core is generally used by bending a multi-hole extruded flat tube called a harmonica tube into a serpentine shape and arranging fins between the parallel parts.

In response to this, recently, based on the demand for reducing refrigerant flow resistance, improving heat exchange efficiency, reducing weight, and reducing thickness, the use of so-called multi-flow heat exchangers as condensers has been proposed and put into practical use. It has come to be For example, as shown in Fig. 7, this multi-flow type heat exchanger connects a large number of flat tubes (23) between a pair of left and right pipe headers (21) (22), and adjacent tubes ( 2
3) By arranging a fin (24) between (23) and partitioning the inside of the headers (21) and (22) with a partition member (25) at an appropriate position in the length direction, the upper end of one header (21) A meandering refrigerant circuit is formed from the refrigerant inlet (26) of the header to the refrigerant outlet (27) at the lower end of the other header (22).

The tubes (23) used in such multi-flow heat exchangers require sufficient pressure resistance to withstand the pressure applied by the high-pressure gaseous refrigerant being handled. A perforated flat tube made of aluminum extrusion is used. That is, as shown in FIG. 8, the peripheral wall (23a) has an elliptical cross section, and has one or more partition walls (23b) continuous in the length direction of the tube to form a plurality of internal spaces. independent refrigerant passage (23c
) is used.

Problems to be Solved by the Invention However, the tube made of the extruded tube as described above (
As long as 23) is used, there are manufacturing technology constraints on reducing the tube height (H), and there are limits to improving the heat exchange efficiency. That is, in order to improve heat exchange efficiency, within the limited area of the heat exchanger core, it is necessary to reduce the flow resistance of the air flowing through the core as much as possible, and to increase the contact area with the air. Although it is effective to measure the height (H) of the tube (23), it is not possible to make the height (H) of the tube (23) sufficiently low.As a result, the tube increases air flow resistance and The number of tubes that can be installed is limited, and the heat transfer contact area with air cannot be sufficiently increased.

To solve these problems, it has recently been proposed to use an electric resistance welded tube as the tube (for example, [1, Japanese Patent Publication No. 62-207572]). In the case of this electric resistance welded tube, the tube wall is sufficiently thin, for example, 0.4 to 0.0 mm. It is possible to make it about 5 wR, and as a result, the tube height can be set to 1.5 to 1.5 wR. It is possible to form an extremely low R of about 7wR.

However, when used as a condenser, the tube made of the ultra-thin-walled electric resistance welded tube does not have the ability to withstand pressure because it handles high-pressure gaseous refrigerant sent from the compressor as mentioned above. There is a significant shortage and it cannot be put to practical use as it is.

For this reason, in the conventional proposal,
As seen in Publication No. 2, an inner fin material formed into a corrugated shape in the width direction is separately inserted into the flat ERW pipe, and by brazing and joining to the inner surface of the pipe wall, the fin material also functions as a reinforcing member. to obtain the required pressure resistance.

However, such conventional electric resistance welded tubes are difficult to manufacture, especially when the height is 1.5 to 1.5 mm.
It is quite difficult to insert the inner fin material over the entire length of the ultra-thin flat tube of 7NIR, which results in poor productivity and high costs.

This invention further solves these problems and improves heat exchange efficiency by making the height of the tube sufficiently low, has sufficient pressure resistance, and is easy to manufacture. It is an object of the present invention to provide a heat exchanger tube suitable for dexterity and a method for manufacturing the same.

Means for Solving the Problems For the above-mentioned purpose, the present invention provides a tube for a heat exchanger in which a pair of upper and lower planar walls facing each other with a predetermined interval are connected at one end via a U-shaped bent part. The tube is made of an electric resistance welded tube formed into a flat shape with an oval cross section by welding the other end in a butt shape, and the upper and lower flat wall portions are formed with an inwardly protruding feature or a plurality of bent protrusions, The top end of the bent protrusion is brought into contact with the inner surface of the opposing flat wall part or the top end of the corresponding bent protrusion protruding from the wall part, so that they are integrally joined by brazing.

Further, in the method for manufacturing a tube for a heat exchanger, one or more bent protrusions are formed on both left and right sides of a band-shaped material having a predetermined width, sandwiching the central bent part, and then the bent protrusions are formed to protrude toward one side. By bending a band-shaped material having a bent protrusion into a U-shaped cross section at the central bending part, and welding both side edges abutting, a flat surface having an oval cross section and in which the bent protrusions face each other vertically is formed. It is formed into a flat tube that protrudes inward from the wall and has its apex abutted against the inner surface of the other flat wall or the apex of a corresponding bent protrusion protruding from the surface, and then the apex of the bent protrusion is brought into contact with the inner surface of the opposite flat wall. It is characterized by brazing and joining the contact surfaces.

The bent protrusions are formed as a continuous bent double wall in the length direction of the tube, and protrude from the upper and lower side plane walls of the tube in an alternate arrangement. The internal space can be partitioned to form a plurality of independent refrigerant passages.

Further, the bent protrusions are formed in the form of a large number of dimples by partially recessing the flat wall portion of the tube, and the large number of dimple-shaped bent protrusions are scattered so that the inside of the tube is The space may also be formed into a stray refrigerant passage.

Embodiment (Embodiment 1) In the embodiment shown in FIGS. 1 and 2, the heat exchanger tubes (1) are arranged at a distance of, for example, 0°8 #lI! between them. Upper and lower planar walls (2) and (3) facing each other with an interval of lI,
It consists of an electric resistance welded tube that is continuous at one end via a U-shaped bent portion (4) and welded (5) in a butt-like manner at the other end to form a flat shape with an oval cross section.

Each of the upper and lower plane walls (2) and (3) has two bent protrusions (6) each protruding inwardly in a manner that they are arranged alternately in the width direction of the tube (1). )
is formed. This bent protrusion (6) is formed as a bent double wall in which the flat wall part (2) is folded inward into a 7-shape and both side walls are brought into close contact with each other.
It is continuous in the length direction. The respective bent protrusions (6) have their top ends abutted against the inner surfaces of the opposing flat wall portions (2) and (3), and are joined and integrated with the inner surfaces by brazing. The bent protrusion (6) itself is also integrated with its double bent walls by brazing the contact surfaces of both walls. These connections are performed by using a double-sided aluminum plating sheet having a brazing material layer on both the inner and outer surfaces as the tube material. Therefore, the joining operation 1 is also performed in conjunction with the brazing joining operation of the fin (24) and the tube (1), and the tube (1) and the header (21) (22) when assembling the heat exchanger.
It is done at the same time.

Therefore, after the brazing, the inner space of the tube (1) is divided into a plurality of independent channels (8) in the width direction using the bent protrusion (6) as a partition wall. It is considered a thing.

The dimensions of the tube (1) are preferably such that the tube wall thickness (1) is 0. 15-0. 5#l11 Especially, for example, 0.4 steel, the tube width (W) is 12 to 20 am, especially, for example, 16 m+, and the tube height (h) is 1.2 to 2.0
m, especially one formed in, for example, 1.6 minutes.

As shown in Figure 2 (b), the tube (1) is manufactured by first placing a band-shaped material (7) of the required width made of an aluminum plating sheet between the left and right sides of the band-shaped material (7), which is to be bent at the center in the width direction. A plurality of bending protrusions (6) are formed on both sides, each protruding toward one side. To form this bent protrusion (6), first, as shown in Fig. 2 (A), in order to correctly set the formation position of the bent protrusion (6), one side wall section is aligned perpendicularly to the plate surface. The other side wall is set at an angle of about 30 degrees (for example) with respect to the one side wall.
The deformed path V-shaped bead part (6
'), and then, as shown in FIG. 2(b), the bead part (6-) is suitably formed by applying a trimming process in which both side walls of the bead part (6-) are brought into close contact with each other and shaped into a predetermined shape, as shown in FIG. I went to Uruchino.

Next, the strip material (7) on which the bent protrusion (6) has been formed is bent into a U-shaped cross section with a predetermined radius of curvature as shown in FIG.
Both side edges (7a) (7a) are bent in a curved shape in opposite directions, and the end faces are butted and electrically welded (5) to form a flat shape with an oval cross section of predetermined dimensions (Fig. 2). ) is manufactured into a tube material as shown in the enlarged view of a portion.

FIG. 3 shows a modified example of the tube (1'), in which the bent protrusions (6a) and (6b) are vertically opposed to each other at the corresponding positions of the two hand side wall portions (2) and (3). The curved protrusion (6
a) (6b) The two pieces are abutted against each other at their top ends and integrally joined together by brazing.

The rest of the structure is the same as that of the embodiment described above, and the manufacturing thereof is also carried out according to the embodiment described above.

(Embodiment 2) FIGS. 4 to 6 show another embodiment. In this embodiment, the tube (11) has a bending protrusion (16) that protrudes inward from both the upper and lower planar wall portions (12) (+3), which partially penetrate the wall portions (12) (13). It is formed into a large number of scattered dimples by recessing it in a substantially hemispherical shape or an abbreviated shape in cross section. , and are integrally joined by brazing. Therefore, the internal space within the tube (11) is formed into a complicatedly bent stray refrigerant passage (18) by the dimple-shaped bent protrusions (16). Therefore, in the tube (+1) of this embodiment, the refrigerant passes through the refrigerant passage (18).
) is agitated by the bent protrusion (16) during the process of flowing through it, further promoting heat exchange.

The rest of the structure of this tube (II) is the same as that of Example 1, and detailed explanation will be omitted.

The tube (11) is manufactured by using a strip material (17) of a predetermined width made of an aluminum plating sheet as a starting material, as shown in FIG. 5 and FIG. After forming the bent protrusion (+6), the material is bent into a U-shaped cross section from the center in the width direction as shown by the chain line in Fig. 6, and the opposite edges are butted against each other to form an electric wire. It is the same as in the case of the first embodiment that a flat tube material is manufactured by sewing and welding (5).

Even in the case of this second embodiment, as a modification thereof, the bending protrusions (16) are formed at different positions on the upper and lower plane wall parts (12) (+3), and the top ends thereof are It may be brought into contact with the inner surface of the wall portion and integrated with the core portion by brazing.

Effects of the Invention Since the tube for a heat exchanger according to the present invention is manufactured as an electric resistance welded tube as described above, the tube wall is made sufficiently thin to make the tube height extremely low. It is possible to manufacture. Therefore, it is possible to increase the number of heat exchangers installed within a predetermined limited area of the heat exchanger core, increase the contact area with the air flowing through the core, and reduce the flow resistance of the air. Therefore, it is possible to construct a heat exchanger with even better heat exchange efficiency.

In addition, although the tube is manufactured as an electric resistance welded tube, bent protrusions are provided protruding from the upper and lower opposing plane wall parts, and the top ends of the tubes are connected to the inner surface of the opposing plane wall part or to the opposing bent protrusions. Since the bent protrusion functions as a reinforcing member, the condenser tube has excellent compressive strength and pressure resistance against internal pressure. In terms of strength, it is comparable to flat tubes made of extruded material.

Furthermore, in terms of manufacturing, predetermined bent protrusions are formed in advance on a flat strip-shaped material, and then the manufacturing process is carried out using conventional electric resistance welding tube manufacturing technology, so there are no manufacturing difficulties. It is easy to use, has excellent productivity, and can be manufactured and provided at low cost.

In addition, when forming the bent protrusion as a continuous part in the length direction of the tube as in claims (2) and (5),
The pressure resistance strength and the bending resistance in the longitudinal direction of the tube can be further improved, and when the bending protrusion is formed as a dimple shape as in claims (3) and (6), The refrigerant flowing through the internal refrigerant passage can be stirred to improve heat exchange efficiency.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a perspective view of a tube, and FIGS.
C) and D are cross-sectional views showing the manufacturing process, and FIG. 3 is a cross-sectional view of a modified tube. Figures 4 to 6 are
This shows an example, and Fig. 4 is a cross-sectional view of the tube, and Fig. 5 is a cross-sectional view of the tube.
The figure is a plan view showing the processing state of the strip-shaped material for its manufacture, and FIG. 6 is a sectional view taken along the line VI--VI in FIG. FIG. 7 is a front view showing an example of a heat exchanger in which the tube according to the present invention is used, and FIG. 8 is a sectional view of a conventional flat tube made of extruded material. (1) (++)...tube, (2) (3)
(12) (13)...Flat wall part, (4)...Bending part, (5) Welding part, (6) (16)...Bending protrusion,
(7) (17)...Band-shaped material, (8) (+8
)...Refrigerant passage. Figure 8

Claims (6)

[Claims] (1) A pair of upper and lower planar walls facing each other with a predetermined interval are connected at one end through a U-shaped bent part, and the other end is welded in a butt-like manner to form a flat shape with an oval cross section. consisting of a sewn tube, one or more bent protrusions projecting inward are formed on the upper and lower planar walls, and the top ends of the bent protrusions protrude from the inner surface of the opposing planar wall or from the wall. A tube for a heat exchanger, characterized in that the tube is brought into contact with the top end of a corresponding bending protrusion and is integrally joined by brazing. (2) The bent protrusions are arranged alternately from both planar walls and are formed as a continuous bent double wall in the length direction of the tube, and the inner space of the tube is divided into a plurality of inner spaces by the bent protrusions. The claim (
1) The heat exchanger tube described above. (3) The bent protrusions are formed in the shape of dimples by partially recessing the flat wall portion inward, and the internal space inside the tube is formed into a stray shape due to the large number of dimple-shaped bent protrusions scattered about. The heat exchanger tube according to claim 1, wherein the tube is formed in a refrigerant passage. (4) One or more bent protrusions protruding to one side are formed on both left and right sides of a strip-shaped material having a predetermined width, sandwiching the central bent portion, and then the strip-shaped material having the bent protrusions is By bending into a U-shaped cross section at the central bending part and welding both side edges abutting,
A flat surface having an oval cross-section and in which the bent protrusion protrudes inward from vertically opposing flat wall parts, and its apex abuts the inner surface of the opposing flat wall part or the apex of a corresponding bent protrusion that protrudes from the surface. A method of manufacturing a tube for a heat exchanger, characterized in that the tube is formed into a tube, and then the top end of the bent protrusion is brazed to the contact surface thereof. (5) The bent protrusions are formed as a continuous bent double wall in the length direction of the strip material, and the bent protrusions protruding from both the upper and lower planar walls are arranged alternately in the width direction of the tube. 5. The method of manufacturing a heat exchanger tube according to claim 4, wherein the inner space of the tube is divided into a plurality of independent refrigerant passages. (6) The bent protrusions are formed in the shape of a large number of dimples scattered on the strip-shaped material, and the internal space within the tube is formed into a stray refrigerant passage by the dotted dimple-shaped bent protrusions. A method of manufacturing a tube for a heat exchanger, characterized in that: