JP2001347329A - Manufacturing method of heat exchanger of car air conditioner and the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to very efficiently mass-produce a communicating tube from a metal tube as a tube stock by a press means and to integrally form a partition wall in the tube in a heat exchanger in which the communicating tubes are connected to respective both ends of parallel train groups of flat tubes. SOLUTION: The method to mass produce the communicating tubes A by a transfer press apparatus comprises a flat face forming process to form a semi flat face 2 by crushing an exposed section of the tube which is sideways housed in a press die at the state its upper side section is exposed and a piercing process to pierce inserting hole 1 groups for inserting ends of the flat tubes. The semi flat face 2 is formed to a waved face shape corresponding to the interval of the inserting hole 1 groups, further, the neighborhoods of their respective valley parts may be locally thinned. The partition wall 4 is integrally press formed with a tube wall.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a car air conditioner or the like of a type in which communication tubes for collecting and distributing a heat transfer medium are connected to both ends of a parallel group of flat tubes through which a heat transfer medium flows. The present invention relates to a method for manufacturing a heat exchanger.

[0002]

2. Description of the Related Art The general structure of a car air conditioner heat exchanger of the above type will be described with reference to FIG. 1 as an embodiment of the present invention. Each of the two ends of the flat tube group B through which the refrigerant flows is inserted into each of a group of slit-shaped insertion holes arranged in the communication pipe A which serves to collect and distribute the heat transfer medium.
It is provided with a configuration in which each insertion portion is air-tightly brazed.

[0003] There are several ways to make this type of communicating tube with a flat tube insertion hole group. In the first conventional manufacturing method, a metal strip is used as a raw material, and first, a large number of insertion holes are formed in a longitudinal direction one by one in a progressive manner.
Thereafter, the perforated plate was rounded into a pipe shape, and the joint was laser-welded. In order to partition the inside of the communication pipe into a plurality of sections, unlike the one of the present invention shown in FIG. 1, a partition wall made separately from the communication pipe is fitted into an insertion hole formed in the pipe wall. It was assembled in the pipe in a way to insert it.

In the second conventional manufacturing method, a metal pipe as a raw material is punched to form an insertion hole group. And the partition wall was provided in the pipe similarly to the above.

[0005]

However, the method of manufacturing a communication pipe using the above-mentioned strip as a material has many disadvantages as described below, and the manufacturing cost is inevitably increased considerably. Was. (1) Laser welding requires considerable skill. (2) Therefore, it is difficult to secure quality control and skilled technicians. (3) It takes time to manufacture the partition wall as a separate part and assemble it in the communication pipe. (4) This assembling process is extremely complicated.

[0006] Also, the method of making a communicating pipe using a pipe as a raw material requires a rather complicated work process as described below, resulting in an increase in processing costs. (5) When punching out the insertion hole, extra troublesome work of inserting and removing a core metal for preventing deformation of the pipe is required. (6) That is, since the burrs protrude into the pipe at the periphery of the punched hole, even if troublesome, the cored bar must be divided into a plurality of parts and cannot be taken out after drilling. (7) It takes time to make the partition walls separately and assemble them in the pipe.

Accordingly, an object of the present invention is to provide a heat exchanger of the type in which communication tubes are respectively connected to both ends of a group of flat tubes arranged in a vertical lattice, and in a process of manufacturing the communication tubes, Production such as laser welding of plate material or insertion / removal operation of split-type core metal at the time of drilling hole in pipe material, and separate production and assembling work of partition wall required in conventional technology It is an object of the present invention to provide a method of manufacturing a heat exchanger for a car air conditioner or the like, which can reduce manufacturing costs, and achieve homogenization and quality improvement of products by eliminating various steps which cause a rise in cost.

[0008]

In order to achieve the above-mentioned object, a method for manufacturing a heat exchanger for a car air conditioner or the like according to the present invention is provided at each end of a group of flat tubes arranged in a vertical lattice.
A method of mass-producing a heat exchanger of a type in which communication pipes are connected to each other using a transfer press device from a metal pipe as a material, in a state where an upper portion thereof is exposed. A flat surface forming step of crushing the exposed portion of the pipe horizontally placed in the press mold to form a quasi-flat surface, and a quasi-flat surface of the pipe housed in the press mold with the quasi-flat surface exposed And a punching step of punching an insertion hole group for inserting an end of the flat tube by a pressing means. Then, the quasi-flat surface may be formed in a wavy shape having a pitch corresponding to the interval between the rows of the insertion holes. In addition, in order to facilitate the formation of the insertion hole, it is preferable to locally thin the vicinity of each valley of the quasi-flat surface having a wavy shape.

Further, in order to form a partition wall for partitioning the inside of the communication pipe into a plurality of sections in the longitudinal direction integrally with the pipe wall, the pipe wall is formed in the vicinity of the section where the partition wall is formed, following the drilling step. It is preferable to provide a partition wall forming step in which the lower surface side of the is pressed into a substantially mountain shape and pressed against the quasi-flat surface.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a heat exchanger for a car air conditioner will be described below with reference to the drawings. The heat exchanger 100 of this embodiment includes:
As shown in FIG. 1, a pair of communication pipes A having a group of slit-shaped insertion holes arranged in a row on the pipe wall are opposed to each other at a predetermined interval, and a pair of insertion holes 1 opposed to each other. Further, a structure is provided in which a state in which both ends of the flat tube B through which the heat transfer medium flows is inserted and fitted is air-tightly fixed by brazing.

The present invention relates to a method of manufacturing a communication pipe A, which is a component of this type of heat exchanger 100.
2 to 5 show the detailed structure of the communication pipe A of this embodiment. In this case, the material of the communication pipe A is an aluminum pipe cut to a predetermined length, and its thickness is 1.2 mm.

FIG. 2 is a partial plan view of the communication pipe A and its h.
FIG. 4 is a vertical cross-sectional view along the -h line. FIG. 3 is a partial front view. FIG.
Partial bottom view and end view. FIG. 5 is a longitudinal sectional view of a portion between the line ii shown in FIG. 3 and a longitudinal sectional view along the line JJ.

As shown in FIG. 2B, the cross-sectional shape of the communication pipe A is not a perfect circle, but a quasi-flat surface 2 is formed by crushing an upper part thereof. The expression “quasi-flat surface” is not limited to a completely flat surface, but may be a curved surface or the like that is appropriately curved. The quasi-flat surface 2 is provided with a large number of insertion holes 1 for inserting the distal end of the flat tube B over a substantially entire length thereof in parallel at a predetermined interval.

As shown in FIGS. 1 and 5, the communicating pipe A whose both open ends are hermetically closed by the cap 3 has a partition wall 4 for dividing the pipe into a plurality of sections in the longitudinal direction. Then, a part of the pipe wall is formed integrally with the communication pipe A by a plastic working method. Reference numeral 5 in the figure denotes a pipe hole provided at a predetermined location on the pipe wall, and a pipe (not shown) for flowing a heat transfer medium is connected thereto. Note that the cap 3 in FIG. 1 is somewhat different from those in the other figures.

Next, a specific example of a method of manufacturing the communication pipe A will be described with reference to FIGS. Communication pipe A
Uses a single aluminum pipe 10 (see FIG. 6) having substantially the same length as its material, and mass-produces it very efficiently using a transfer press device, except for a post-process in which caps 3 are fitted to both ends. You can do it.

In each step of this series of press working,
This will be described below in order. First, in the flat surface forming step as the first stage, the lower half portion of the pipe 10 serving as the material of the communication pipe A is horizontally placed in the lower mold 21 of the press mold as shown in FIG. Further, the upper mold 22 is placed thereon. The upper die 22 is provided with a groove-shaped opening 22a having a width substantially equal to the width of the quasi-flat surface 2 of the communication pipe A and narrower by a predetermined dimension than the diameter of the pipe 10 in the longitudinal direction.

The upper portion of the pipe 10 is crushed into the groove-shaped opening 22a, and a pressing die 23 for forming the quasi-flat surface 2 is fitted as shown in FIG. The upper mold 22 is
As can be understood from FIG. 9, the pressing pressure exerted by the pressing die 23 serves to prevent deformation of the shoulders (indicated by the symbol d) of the pipe 10.

The quasi-flat surface 2 is not a mere flat surface, but has a wavy shape having a pitch corresponding to the interval between the rows of insertion holes 1 provided on this surface as shown in FIG. It is desirable to form. At this time, by making each valley portion of the waveform thinner than the other portions as shown in the drawing, it becomes easier to form the insertion hole 1 more easily and accurately in the next drilling step.

In this flat surface forming step, as shown in FIG. 9, a round bar-shaped core 24 having a diameter slightly smaller than the inner diameter of the pipe 10 may be fitted into the pipe 10. Thereby, the pipe 10 can be reliably formed into a desired cross-sectional shape. The core 24 differs from the conventional split-type core in terms of its shape and dimensions, and can be easily inserted and removed.

Next, as shown in FIG. 8, the process proceeds to a perforation step of arranging a group of insertion holes 1 on the quasi-flat surface 2. The press die used in this step is, as shown in FIGS.
A group of cutting blades 25 for perforation is assembled and placed in the groove-shaped opening 23a corresponding to each formation position of the group of insertion holes 1. Reference numeral 22 in FIG. 10 denotes a lower mold. A spring 27 is attached to the upper die 23.

Further, a punch 26 for preventing the pipe 10 and the cutting blade 25 from moving relative to each other in the drilling step.
The group is placed in the groove-shaped opening 23a in the arrangement shown in FIG. The shapes of the cutting blade 25 and the punch 26 are shown in FIGS. As shown in FIG. 8A and FIG. 2, when a group of punches 26 strongly presses a predetermined portion on the quasi-flat surface 2, a dent-shaped high-pressure spot e is formed at each portion.

In the drilling step, unlike the prior art described at the beginning, it is not necessary to insert a split-type metal core for preventing deformation, which is extremely troublesome to insert and remove, in the pipe 10 beforehand. Not at all.

The reason why the core metal is not required is that the outer peripheral surface of the pipe 10 except for the quasi-flat surface 2 is replaced with the lower mold 21 and the upper mold 2.
2 and that the quasi-flat surface 2 provided with the insertion hole 1 is formed into a wavy surface that is difficult to deform.
This is due to various countermeasures such as preliminarily reducing the thickness of each valley portion of the waveform to which the cutting blade 25 is pressed.

Next, the pipe 10 in which the group of insertion holes 1 has been formed
The partition wall forming step of forming the partition wall 4 integrally with the pipe 10 at a predetermined position in the pipe by plastic working will be described with reference to FIGS. The structure near the location where the partition wall 4 is formed is as shown in FIG.

The structure of the press die used in this step is shown in FIG.
FIG. 3 shows a schematic longitudinal sectional view. The lower mold 31 that supports the pipe 10 in which the group of insertion holes 1 has been formed has three (or more) different types of receiving molds 3 each having a different shape at the location where the partition wall 4 is formed.
There is provided a mounting hole 31a into which the 2A to 32C can be freely inserted. On the other hand, the upper die 33 is formed with a pressing surface 33a having an uneven shape corresponding to the quasi-flat surface 2 on which the insertion hole group 1 has been formed.

In order to form the partition wall 4 at a predetermined position in the pipe 10 using the above-described press die, first, as shown in FIG. 14, the pipe 10 is preformed. That is, (c) of FIG.
The receiving mold 32A shown in FIG. The left side of the figure is a front view, and the right side is a side view.

When press molding is performed using the receiving mold 32A,
The pipe 10 is, as shown in FIG.
Is formed into a curved mountain shape in the longitudinal direction of the pipe, and a substantially trapezoidal shape in the width direction.

Subsequently, the process proceeds to the intermediate forming process described in FIG. In this step, the receiving mold 32A is replaced with a receiving mold 32B having the shape shown in FIG. Receiving mold 3
2B differs from the receiving mold 32A in that a small protruding portion f is provided at the top of a curved chevron. This small protrusion f
As shown in (b), the quasi-flat surface 2 having a wavy shape is positioned so as to face one mountain portion.

Next, the process proceeds to the final forming process described in FIG. In this molding step, instead of the receiving mold 32B,
The receiving die 32C having the shape shown in FIG.
The difference from the receiving die 32B lies in that the small protrusion g is extended to a height reaching the quasi-flat surface 2 and that the shape of the pressure receiving surface matches the upper surface shape of the quasi-flat surface 2.

As described above, by dividing the partition wall forming step into a plurality of steps and performing the steps in stages, the area where the partition wall 4 is formed,
In particular, it is possible to eliminate the risk of cracks at the locations where the small protruding portions f and g at the peaks of the chevron are subjected to severe plastic deformation force. In the partition wall forming step, hot pressing may be performed. Further, the partition wall 4 can be formed at a plurality of places at once.

Finally, the communication pipe A is completed by fitting the caps 3 to both open ends of the pressed pipe 10 and brazing it airtightly.

[0032]

As is apparent from the above description, according to the method of manufacturing a heat exchanger for a car air conditioner or the like according to the present invention, a metal strip having a flat tube insertion hole previously formed into a pipe shape. In comparison with the conventional manufacturing method in which an insertion hole is punched and formed in a pipe in which a rounded or welded or a split type core metal for deformation prevention is inserted, excellent effects as listed below are obtained,
In general, the production cost of the heat exchanger can be remarkably reduced, and the homogenization and high quality of the product can be achieved. (A) Most of the production process of the communication pipe can depend on the transfer press device, so that productivity is extremely high. (B) Laser welding is not required, requiring considerable skill. (C) Therefore, quality control becomes easy, and a skilled technician becomes unnecessary. (D) When punching and forming the insertion hole of the flat tube, a split-type core metal for preventing pipe deformation is inserted and removed.
Extremely cumbersome extra work can be saved. (E) By forming the quasi-flat surface in a wavy shape with a pitch corresponding to the interval between the rows of insertion holes, deformation of the pipe during drilling can be prevented. (F) Further, if the vicinity of each valley of the wavy shape is locally thinned, the insertion hole can be formed more easily and accurately. (G) Since the partition wall can be press-formed integrally with the tube wall,
An extremely complicated process of manufacturing the partition wall as a separate part and assembling it in the communication pipe can be omitted.

[Brief description of the drawings]

FIG. 1 shows one embodiment of the present invention, and is a partially broken front view of a heat exchanger.

FIG. 2 is a partial plan view and a vertical cross-sectional view of the communication pipe according to the first embodiment;

FIG. 3 is a partial front view of the communication pipe;

FIG. 4 is a partial bottom view and an end view of the communication pipe;

FIG. 5 is a vertical sectional view taken along line ii of FIG. 3 and a vertical sectional view taken along line JJ of FIG. 3;

FIG. 6 is a longitudinal sectional view of a pipe as a material of the communication pipe in a cylinder circumferential direction and a cylinder length direction.

FIG. 7 is a diagram corresponding to FIG. 6, showing a pipe having undergone a flat surface forming step.

FIG. 8 is a diagram corresponding to FIG. 6 of the pipe after the drilling step.

FIG. 9 is a schematic longitudinal sectional view of a press die used in the flat surface forming step.

FIG. 10 is a schematic longitudinal sectional view of a press die used in the punching step.

FIG. 11 is a front view and a side view of the cutting blade.

FIG. 12 is a front view and a side view of the punch.

FIG. 13 shows the press mold used in the partition wall forming step.
FIG. 3 is a schematic longitudinal sectional view.

14 is a diagram corresponding to FIG. 6 and a front view and a side view of a receiving mold, illustrating a preliminary processing step of a partition wall forming step.

FIG. 15 is a diagram corresponding to FIG. 14, illustrating an intermediate processing step of the partition wall forming step.

FIG. 16 is a view corresponding to FIG. 14, illustrating a final processing step of the partition wall forming step.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 heat exchanger A communication tube B flat tube 1 insertion hole 2 semi-flat surface 3 cap 4 partition wall 5 pipe hole 10 pipe 21 lower mold 22 upper mold 22a grooved opening 23 press mold 24 core metal 25 cutting blade 26 punch 27 Spring 31 Lower die 31a Mounting hole 32A-32C Receiving die 33 Upper die 33a Pressing surface d Both shoulders e High pressure spot f, g Small protrusion

Claims (4)

[Claims] 1. A heat exchanger of the type in which communication tubes are respectively connected to both ends of a group of flat tubes arranged in a vertical lattice, and the communication tubes are formed from a metal pipe as a material by a transfer press. A method of mass-producing using a device, comprising: a flat surface forming step of forming a quasi-flat surface by crushing an exposed portion of a pipe housed laterally in a press mold with an upper portion thereof being exposed; A piercing step of piercing a group of insertion holes for inserting the end of a flat tube into a quasi-flat surface of a pipe housed in a press mold with a flat surface exposed by a pressing means. A method of manufacturing a heat exchanger for a car air conditioner or the like. 2. The heat exchanger for a car air conditioner or the like according to claim 1, wherein the quasi-flat surface is formed in a wavy shape having a pitch corresponding to an interval between the insertion holes. Method. 3. A quasi-flat surface having a wavy shape, in which the vicinity of each valley is locally thinned to facilitate piercing of the insertion hole. A method for producing a heat exchanger for a car air conditioner or the like as described in the above. 4. In order to form a partition wall for partitioning the interior of the communication pipe into a plurality of sections in the longitudinal direction integrally with the pipe wall, following the drilling step, in the vicinity of the location where the partition wall is formed,
4. The heat exchanger for a car air conditioner or the like according to claim 1, wherein a partition wall forming step is provided, wherein a lower surface side of the pipe wall is pressed into a substantially mountain shape and pressed against a quasi-flat surface. Production method.