JPH04162931A - Method for forming beads for heat exchanging tube - Google Patents

Abstract

PURPOSE:To easily form beads and to obtain a heat exchange tube excellent in heat exchange efficiently by inserting bead forming dies into a heat exchange tube to press-form beads and then melting the bead forming dies to remove them from the heat exchange tube. CONSTITUTION:The bead forming dies 4 are inserted into prescribed positions of passages 2 of the heat exchange tube 1 and projecting parts 8 for forming the beads are positioned after each bead forming hole 6 and the press dies 10, 12 are pressurized at a prescribed force to press the heat exchange tube 1. Thereafter, the bead forming dies are heated at a prescribed temperature, melted and removed from the heat exchange tube.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming beads on a heat exchange tube used in a heat exchanger for a vehicle air conditioner.

(Prior Art) Generally, in this type of heat exchanger, one in which a heat exchange tube is constructed by joining two molded plates is well known (for example, Japanese Utility Model Application Publication No. 15498/1983) reference).

However, in the case of a structure in which two molded plates are joined as described above, for example, when water in the heat exchange medium expands, cracks may occur in the joined part due to the stress. Yes, and strength is required at the joint. Further, there were problems in that it was difficult to properly join the molded plates, and it was not easy to join them.

As a prior art for dealing with this problem, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. 1-20922. This prior art has a structure in which plates are not joined, and a heat exchange tube is formed by roll forming a cylindrical vibe member into a flat shape. Heat exchange tubes formed in such a manner have no joints, thus avoiding the problems described above.

(Problems to be Solved by the Invention) However, in the above-mentioned prior art, although it is possible to manufacture a heat exchange tube having a flat heat exchange medium passage, the heat exchange medium may protrude into the heat exchange medium passage. The problem was that beads that would cause turbulent flow could not be formed by press molding. However, the inside of the heat exchange tube is hollow, and if the bead is press-molded, other parts will also be deformed.

In view of the above-mentioned problems, the present invention provides a heat exchange tube in which a cylindrical vibe member is roll-formed into a flat shape, and a bead forming method for a heat exchange tube that is capable of forming beads on the heat exchange tube. The purpose is to provide

(Means for Solving the Problems) In order to achieve the above object, a heat exchange tube bead forming method according to the present invention includes roll forming a cylindrical vibe member into a flat shape to form a heat exchange tube. A bead molding die having a plurality of bead forming holes drilled in a staggered manner is made of a low-temperature melting material that melts at a predetermined temperature or lower, and the bead molding die is inserted into the internal passage of the heat exchange tube to form the beads. It is press-molded.

(Function) Therefore, when a bead molding die is inserted into the heat exchange tube and pressing is performed in accordance with the bead forming hole of the bead forming die, a bead is formed in the portion corresponding to the bead forming hole. . Here, the other portions where the beads are not molded do not deform because the bead molding die is interposed. After that, the bead mold is heated to melt it and removed from the heat exchange tube, thereby solving the above problem.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In this example, an example of a method of constructing a heat exchange tube having a substantially U-shaped heat exchange medium passage used in a so-called single tank structure heat exchanger and forming beads on the heat exchange tube will be described. .

FIG. 1 shows a heat exchange tube formed by roll-forming a cylindrical vibe member (not shown) into a flat shape. A passage 2 for forming a medium passage 22 is provided, and both ends in the longitudinal direction are open. The width and length of the passage 2 of this heat exchange tube 1 in the transverse direction and the longitudinal direction are A, B, and C. In order to form beads on the heat exchange tube 1, a bead mold 4 described below is used.

The bead mold 4 is made of a low-melting material (such as ice or solder).
As shown in Fig. 2, it is formed into a roughly U-shape, with a plurality of bead-forming holes 6 of a predetermined diameter formed almost all over the body. The holes are arranged in a staggered pattern. The width E of the bead mold 4 in the lateral direction and the longitudinal direction is approximately the same as the width A, B of the passage 2 of the heat exchange tube 1 in the lateral direction and the longitudinal direction, or is slightly larger than that. The length F is set to be shorter than the length C of the passage 2 of the heat exchange tube 1 by a predetermined amount. That is, this bead mold 4 is inserted into the passage 2 of the heat exchange tube 1 as described below.

Beads are formed on the heat exchange tube 1 using this bead mold 4.

The procedure is, first, as shown in FIG. 3, a bead mold 4 is inserted into a predetermined position within the passage 2 of the heat exchange tube 1. Next, as shown in FIG. 4, the bead forming protrusions 8 of the press mold 10.12 for performing bead forming are positioned in line with the respective bead forming holes 6 of the bead forming mold 4, and the press The heat exchange tube 1 is pressed by pressing the mold 10° 12 with a predetermined force. In addition to the bead forming protrusion 8, the press mold 10.12 is provided with a partition forming protrusion 14 and a folded part forming protrusion (not shown), and the press forms a plurality of beads. A heat exchange tube 1'' having a heat exchanger tube 16, a partition portion 18, a folded portion 20, and a substantially U-shaped heat exchange medium passage 22 is formed as shown in FIG.

During this press molding, parts other than the bead 16, partition part 18, and folded part 20 are not deformed because the bead mold 4 is interposed inside. Thereafter, the bead mold 4 is heated at a predetermined temperature to melt it and removed from the heat exchange tube 1'.

Here, to explain a little more about the above procedure, for example, if the bead mold 4 is formed of ice, the bead molding is performed in a cold room where the ice does not melt. Also,
If the bead mold 4 is made of solder, it is melted by heating to about 120-130''C, for example.

The beads of the heat exchange tube formed in this manner serve to create turbulence in the heat exchange medium flowing in the heat exchange medium passage, thereby improving the heat exchange efficiency of the heat exchanger.

In this heat exchange tube bead forming method, a bead mold is inserted into the heat exchange tube to press-form the bead, and then the bead mold is melted and removed from the heat exchange tube. Therefore, beads can be easily formed without deforming other parts of the heat exchange tube, and a heat exchange tube with high pressure resistance and good heat exchange efficiency can be provided.

Another embodiment of a heat exchange tube constructed by the bead forming method according to the present invention is shown in FIG.

In the heat exchange tube 30 shown in FIG. 6, a partition 32 is press-molded in the center, and heat exchange medium passages 34, 36 are provided on both sides of the partition 32.
A bead of 3 days was press-molded on the entire surface of the 36-mm. In order to form this heat exchange tube 30, two bead molds 40 shown in FIG. 7 are used.

The bead molding mold 40 has a substantially rectangular shape, and is made of a low-temperature melting material such as ice or solder as described above, and has a plurality of bead molding holes 42 of a predetermined diameter arranged in a staggered manner over almost its entirety. It has been drilled.

However, these 402 sets of bead forming molds were inserted into the heat exchange tube 1 shown in the first example, and the bead forming protrusions and partition forming protrusions were formed by the same procedure as in the first embodiment described above. By pressing using a press mold (not shown) provided with a bead 38, the heat exchange tube 30 described above can be formed.

(Effects of the Invention) As described above, according to the present invention, a bead mold is inserted into a heat exchange tube to press-form the bead, and then the bead mold is melted and removed from the heat exchange tube. Therefore, beads can be easily formed without deforming other parts of the heat exchange tube, and a heat exchange tube with high pressure resistance and good heat exchange efficiency can be provided.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the heat exchange tube before forming beads, FIG. 2 is a perspective view of a bead molding die according to the first embodiment of the present invention, and FIG. FIG. 4 is a diagram illustrating press molding, FIG. 5 is a perspective view of a heat exchange tube with beads formed therein, and FIG. 6 is a diagram showing a second embodiment of the present invention. A perspective view of such a heat exchange tube, and FIG. 7 is a perspective view of a bead mold for constructing the heat exchange tube of FIG. 6. 1.1", 30...heat exchange tube, 4,40...
Bead mold, 6.42... Hole for bead molding, 16.
38... Bead. Figure 1 Figure 2 Figure 6 Figure 7

Claims (1)

[Claims] A heat exchange tube is formed by roll-forming a cylindrical pipe member into a flat shape, and a bead molding die having a plurality of bead-forming holes drilled in a staggered manner is melted at a predetermined temperature or lower. 1. A method of forming beads for a heat exchange tube, the method comprising: forming beads using a low-temperature melting material; and inserting the bead mold into an internal passageway of the heat exchange tube to press-form the beads.