JPH09192761A - Method and device for flaring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent defective flare working, and to obtain uniform brazing. SOLUTION: In this method, a pipe 6 is flared by inserting a flare punch 11 from the tip part of the pipe 6 of a heat exchanger 1 consisting of plural laminated fins 3 and the U-shaped pipe 6 piercing these fins 3. In this case, flaring must be performed by inserting the flare punch 11 while pressuring the end face of the pipe 6 on a side on which the flare punch 11 is inserted, by a pressure punch 38 in the axial direction of the pipe 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe expanding method and device for expanding pipes penetrating fins when assembling a heat exchanger of an air conditioner, for example.

[0002]

2. Description of the Related Art A fin tube heat exchanger for exchanging heat with air is provided in an indoor unit and an outdoor unit of an air conditioner or a radiator of an automobile. In this heat exchanger, a plurality of laminated fins and a pipe as a tube penetrating the fins are arranged in a meandering shape. In the air conditioner, a refrigerant such as CFC gas flows through the inside of the pipe, and in the radiator, cooling water flows.

FIGS. 4 (a) and 4 (b) show a heat exchanger 1 of an air conditioner, in which a large number of fins 3 made of aluminum or the like are provided between a pair of upper and lower end plates 2 and 2 at a predetermined interval. Overlaid. A plurality of through holes 4 are formed in the plate surface of the fin 3 including the end plate 2, and a pipe 5 made of a copper pipe penetrates the through holes 4.

The pipe 5 is a U-shaped pipe 6 having a long axis.
And a return bend pipe 7 that connects the opening 6a of the U-shaped pipe 6, and at the time of assembly, first, the long-axis U-shaped pipe 6 is inserted from one end plate 2 side to the through hole 4 of the fin 3. It is made to project from the other end plate 2 inserted in.

Next, the U-shaped pipe 6 is expanded (expanded) by means to be described later so that the U-shaped pipe 6 is finned 3.
After the pipe expanding step of closely contacting the through hole 4 of the U-shaped pipe 6, the opening 6a of the U-shaped pipe 6 is flared, and the return bend pipe 7 is inserted into the opening 6a for brazing and fixing. There is.

The pipe expanding device used in the pipe expanding step is constructed as shown in FIG. 5, and the heat exchanger 1 has a U-shaped receiving part 8 which follows the return part 6b of the U-shaped pipe 6. It is horizontally supported by a support base 9.

The pipe expanding device is equipped with a mandrel 10 which is inserted into the straight portion of the U-shaped pipe 6, and the tip of the mandrel 10 has a U-shaped pipe 6 for expanding the pipe.
A tube-shaped expansion punch 11 having a diameter larger than the inner diameter of is fixed by a screw 12. At the base end of the mandrel 10, a secondary flare processing part 1 having a diameter larger than that of the mandrel 10.
3 and a third flare processing portion 14 having a larger diameter are continuously provided in the axial direction so that the flare processing can be performed on the opening 6a.

The base end of the mandrel 10 is connected to a pressure drive mechanism (not shown) which uses a servomotor or the like as a drive source, and the mandrel 1 is connected by this pressure drive mechanism.
0 moves back and forth in the axial direction of the straight portion of the U-shaped pipe 6. In addition, in FIG. 5, one U
Although the straight part of the straight pipe 6 is expanded, the mandrel 10 corresponding to the number of straight parts of the U-shaped pipe 6 of the heat exchanger 1 is arranged in parallel, and a plurality of expansion pipes are performed simultaneously. Be seen.

Therefore, when the mandrel 10 is advanced by the pressure driving mechanism, the pipe expanding punch 11 is inserted from the opening 6a of the U-shaped pipe 6, and the straight portion of the U-shaped pipe 6 is expanded as the mandrel 10 advances. Then, the fins 3 are closely attached to the through holes 4. When the secondary flare processing portion 13 reaches the opening 6a by expanding the pipe, the opening 6a is expanded to a larger diameter to form the secondary flare 15, and then the tertiary flare processing portion 14 arrives. Then, the third flare 16 is formed by expanding the pipe to a larger diameter. When the third flare processing section 14 reaches the opening 6a,
The straight portion of the U-shaped pipe 6 is set to be expanded over the entire length, and when the expansion is completed, the mandrel 10 is retracted by the pressure driving mechanism, and the expansion pipe punch 11 is included from the U-shaped pipe 6. The mandrel 10 is removed. At this time, since the end plate 2 of the mandrel 10 in the pulling direction contacts the stripper 17, the mandrel 10 can be smoothly pulled out.

[0010]

However, in the pipe expanding step described above, in order to press the pipe expanding punch 11 into the U-shaped pipe 6 and expand the diameter of the straight portion,
According to the law of constant volume, the straight portion contracts in the axial direction by an amount corresponding to the plastic deformation, and the projection length of the opening 6a protruding from the end plate 2 varies.

If the projection length of the opening 6a of the U-shaped pipe 6 is varied in this way, the mandrel 10 is expanded during pipe expansion.
The secondary flare processing portion 14 and the tertiary flare processing portion 15 provided at the base end portion of the pipe do not sufficiently hit the end portion of the pipe and a predetermined flare processing cannot be performed, or conversely, the secondary flare processing portion 14 and The third flare processing portion 15 may be deeply inserted into the end portion of the pipe and cracks may occur in the flare.

Even if the flare is not cracked, if the projection length of the opening 6a of the U-shaped pipe 6 varies, the return bend pipe 7 tilts when the return bend pipe 7 is inserted, and 3 When the brazing filler metal is put into the next flare 16 and brazing is performed, the height of the heating burner is constant, and thus the variation in height causes variation in heating, resulting in poor brazing and causing gas leakage. There's a problem.

The present invention has been made in view of the above circumstances. A first object of the present invention is to make the lengths of the pipes uniform and to insert the return bend pipe straight.
It is another object of the present invention to provide a tube expanding method and apparatus capable of preventing defective flare processing and uniform brazing.

It is a second object of the present invention to provide a pipe expanding method and apparatus capable of flaring the end of the pipe together with the pipe expanding and improving the productivity. A third object of the present invention is to provide a pipe expanding method and a pipe expanding method which can pressurize the pipes in a uniform length in synchronization with the pipe expanding and prevent deformation of the pipes without applying excessive force to the pipes. Especially.

[0015]

In order to achieve the above object, the present invention provides a heat exchanger comprising a plurality of laminated fins and pipes penetrating the fins, and the end of the pipe. In a pipe expanding method of inserting a pipe expanding punch from a portion, the pipe expanding punch is inserted while the end face of the pipe on the side where the pipe expanding punch is inserted is pressed in the axial direction of the pipe. And

According to a second aspect of the present invention, there is provided a pipe expanding method for expanding a pipe by inserting a pipe expanding punch from an end portion of the pipe of a heat exchanger having a plurality of laminated fins and a pipe penetrating the fins. The end face of the pipe on the side where the expansion pipe punch is inserted is expanded by inserting the expansion pipe punch while pressurizing the end face of the pipe in the axial direction of the pipe by the flare processing part, and flaring the end part of the pipe by the flare processing part. It is characterized by

According to a third aspect of the present invention, the means for pressurizing the end surface of the pipe is a pressure punch driven by a servomotor. According to a fourth aspect of the present invention, the means for pressurizing the end surface of the pipe is a pressure punch driven by a hydraulic cylinder.

According to a fifth aspect of the present invention, the means for pressurizing the end surface of the pipe is a pressure punch driven by the gravity of the weight. A pipe expanding device for expanding the pipe of a heat exchanger comprising a plurality of laminated fins and pipes penetrating the fins, wherein the pipe is inserted from the end of the pipe into the pipe. A punch, a pressure punch that abuts the end surface of the pipe on the side where the pipe expansion punch is inserted, and the pipe expansion punch and the pressure punch are advanced in synchronism to press the pipe end surface in the axial direction of the pipe. However, a pressure drive mechanism for expanding the tube by inserting the tube expansion punch is provided.

According to a seventh aspect of the present invention, the pressure punch is a flared portion. According to an eighth aspect of the present invention, the pressure driving mechanism is a servo motor. According to the present invention, since the lengths of all the pipes are made constant, the return bend pipe can be inserted straightly without any difficulty, and the flared portion is shallowly inserted or too deeply inserted during flare processing. It is possible to form a flare of a certain shape without causing the occurrence of unevenness, and it is possible to prevent heating variations during brazing.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show the first embodiment, in which the same components as those of the prior art are denoted by the same reference numerals and description thereof is omitted. FIG. 1 shows the entire structure of the pipe expanding device, and FIG. 2 shows the pipe expanding state.

Reference numeral 21 shown in FIG. 1 is a pressurizing drive mechanism, which is provided with an upwardly-facing U-shaped lifting frame 22. The left and right support columns 23 of the elevating frame 22 are provided with screwing portions 25 that are screwed into the lower end portions of the pair of left and right first screw rods 24, and the upper end portion of the first screw rod 24 has a bevel gear. It is linked to the built-in first gabox 26.

A pair of left and right first gearboxes 26 are connected by a connecting shaft 27, and a first servomotor 28 is directly connected to one end of the connecting shaft 27. Then, the rotational force of the first servomotor 28 is transmitted to the pair of left and right first gearboxes 26 via the connecting shaft 27, and to the pair of left and right first screw rods 24 via the first gearbox 26. It is being transmitted. Therefore, the forward / reverse rotation of the first screw rod 24 can raise and lower the elevating frame 22 via the screwing portion 25 that is screwed with the first screw rod 24.

A pair of left and right second screw rods 29 are provided in parallel with the first screw rod 24 between both columns 23 of the elevating frame 22. A screwing portion 31 provided on the elevating plate 30 is screwed to the pair of left and right second screw rods 29, and the elevating plate 30 is supported in a horizontal state.

The upper end portions of the pair of left and right second screw rods 29 have a second gear box 32 having a built-in bevel gear.
It is linked to. The pair of left and right second gaboxes 32 are connected by a connecting shaft 33, and a third gabox 3 having a bevel gear built therein is provided in an intermediate portion of the connecting shaft 33.
4 is interlocked with the drive shaft 35, and the drive shaft 35
A second servomotor 36 is directly connected to one end of the.

The rotational force of the second servo motor 36 is transmitted to the third gearbox 34 via the drive shaft 35, and is further transmitted to the pair of left and right second gearboxes 32 via the connecting shaft 33. It has become so. Further, it is transmitted to the pair of left and right second screw rods 29 via the second gearbox 32. Therefore, the elevating plate 30 can be moved up and down by the forward and reverse rotation of the second screw rod 29 through the screwing portion 31 that is screwed with the second screw rod 29.

A base end portion of the mandrel 10 to be inserted into the U-shaped pipe 6 is fixed to the elevating plate 30, and a pipe expanding punch 11 is provided at the tip end portion. Mandrel 1
Reference numeral 0 is slidably inserted into a guide hole 37 formed in the elevating frame 22, and is regulated so that the mandrel 10 is vertically moved.

A cylindrical pressure punch 38 is provided so as to project downward on the lower surface of the elevating frame 22 and at the peripheral portion of the guide hole 37. The pressure punch 38 is provided with the mandrel 10. They are fitted together, and the lower end surface thereof is in contact with the end surface of the opening 6 a of the U-shaped pipe 6. 1 and 2, the straight portion of one U-shaped pipe 6 is expanded, but the U of the heat exchanger 1 is shown.
The mandrel 10 corresponding to the number of straight portions of the character-shaped pipe 6 is arranged in parallel on the elevating plate 30, and a plurality of pipes are expanded at the same time.

Next, the operation of the tube expanding device configured as described above will be described. First, the first of the pressure drive mechanism 21
The servo motor 28 and the second servo motor 36 are simultaneously driven, and the rotational force of the first servo motor 28 becomes
It is transmitted to the pair of left and right first gear boxes 26 via 7, and is transmitted to the pair of left and right first screw rods 24 via the first gap box 26.

Therefore, the first screw rod 24
The rotation of the lowering mechanism lowers the elevating frame 22 via a screwing portion 25 that is screwed to the pressurizing punch 3 provided on the elevating frame 22.
8 axially presses the end surface of the opening 6a of the U-shaped pipe 6. The rotational force of the second servo motor 36 is transmitted to the third gearbox 34 via the drive shaft 35, and further, the pair of left and right second gearboxes 3 is connected via the connecting shaft 33.
2 is transmitted.

Further, since it is transmitted to the pair of left and right second screw rods 29 via the second gearbox 32, it is passed through the screwing portion 31 that is screwed with the second screw rods 29 by the rotation of the second screw rods 29. The elevating plate 30 descends. The mandrel 10 advances (descends) by descending the elevating plate 30.
Then, the pipe expanding punch 11 is inserted from the opening 6a of the U-shaped pipe 6, and as the mandrel 10 advances, the straight portion of the U-shaped pipe 6 is expanded and brought into close contact with the through hole 4 of the fin 3.

Therefore, the end face of the U-shaped pipe 6 on the side where the pipe expanding punch 11 is inserted can be expanded by the pipe expanding punch 11 while axially pressing the end face of the pipe 6.
Although the straight portion of the U-shaped pipe 6 contracts in the axial direction due to the expansion, the pressurizing punch 38 advances in accordance with the amount of contraction, and thus the shortest of the plurality of U-shaped pipes 6 (end plate 2 It is possible to make the heights of the other pipes uniform based on the amount of projection of the pipe protruding from).

When the expansion of the straight portion of the U-shaped pipe 6 is completed in this way and the heights of the openings 6a are made uniform, the first servomotor 28 and the second servomotor 36 are reversed. Then, the elevating frame 22 rises to separate the pressure punch 22 from the opening 6a, and the elevating plate 30 also rises to remove the mandrel 10 from the straight portion of the U-shaped pipe 6.

The opening 6 of the U-shaped pipe 6 whose expansion has been completed
Since the heights of a are made uniform, the opening 6a is expanded to a larger diameter to form the secondary flare 15 at the time of flare processing in the post-process, and then the tertiary flare 16 is formed. Although the flare is formed, the flared portion is not inserted too shallowly or too deeply at the time of flaring, and a flare of a certain shape can be formed, so that heating variation during brazing can be prevented.

FIG. 3 shows a second embodiment. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In the present embodiment, the flared portion 40 having a pressure punch function is fitted to the base end of the mandrel 10 so as to be slidable in the axial direction. This flare processing part 4
Reference numeral 0 indicates a secondary flare processing portion 41 having a diameter larger than that of the mandrel 10 and a tertiary flare processing portion 42 having a diameter larger than that of the mandrel 10.
The tip end surface of the next flare processing portion 41 comes into contact with the end surface of the opening 6a of the U-shaped pipe 6 so that pressure can be applied in the axial direction.

Therefore, according to the present embodiment, as in the first embodiment, when the elevating frame 22 and the elevating plate 30 are lowered, the flare processing portion 40 is lowered integrally with the mandrel 10 at the time of pipe expansion and the U-shaped pipe. The pipe expanding punch 11 while pressurizing the end surface of the opening 6a of 6 by the flare processing portion 40.
Can be expanded by. After the expansion of the straight portion of the U-shaped pipe 6 is completed, only the flare processing portion 40 is further lowered by the elevating frame 22 so that the opening 6a is expanded to a large diameter by the secondary flare processing portion 41. The secondary flare 15 is formed, and then the tertiary flare processing part 42 expands the pipe to a larger diameter to form the tertiary flare 16.

Therefore, the opening 6a of the U-shaped pipe 6
The flare processing portion 40 can pressurize and make uniform the heights, and the flare processing portion 40 can form the secondary flare 15 and the tertiary flare 16 in the opening 6a.

According to the above-mentioned embodiment, the pressurizing drive mechanism is provided with the servomotor to move up and down the mandrel, the pressurizing punch and the flare processing section. However, the servomotor is not limited to the hydraulic cylinder or the weight. You may make it pressurize using gravity.

Further, the U-shaped pipe of the heat exchanger is vertically supported, the opening is directed upward, and the pipe is expanded by the mandrel descending from above, but the U-shaped pipe is supported downward or sideways. You can also expand the tube.

[0039]

As described above, according to the first aspect of the present invention, since the lengths of the pipes can be made uniform, the return bend pipe can be inserted straight and the flare processing defect. It is possible to prevent the above-mentioned problem and to have the effect that the brazing can be made uniform.

According to the second aspect, it is possible to flare the end portion of the pipe together with the expansion of the pipe, and it is possible to improve the productivity. According to the third to fifth aspects, the structure is simple, and the pressurization can be performed in synchronization with the pipe expansion, and there is an effect that the deformation of the pipe can be prevented without applying an excessive force to the pipe.

According to the sixth to eighth aspects, it is possible to provide a pipe expanding device in which the lengths of the pipes are made uniform, the return bend pipes can be inserted straight, and flare processing defects can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing the overall configuration of a tube expanding device according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional front view showing a pipe expanded state of the same embodiment.

FIG. 3 is a vertical sectional front view showing a pipe expanded state according to a second embodiment of the present invention.

FIG. 4 shows a general heat exchanger, (a) is an overall perspective view, and (b) is a perspective view of a return bend pipe portion.

FIG. 5 is a vertical sectional front view showing a pipe expanding state in a conventional pipe expanding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heat exchanger 3 ... Fins 6 ... U-shaped pipe 10 ... Mandrel 11 ... Expansion punch 21 ... Pressurization drive mechanism 28, 36 ... Servo motor 38 ... Pressurization punch 40 ... Flare processing part

Claims (8)

[Claims] 1. A pipe expanding method for expanding a pipe by inserting a pipe expanding punch from an end portion of the pipe of a heat exchanger including a plurality of laminated fins and a pipe penetrating the fins, the pipe expanding punch comprising: A pipe expanding method in which the pipe expanding punch is inserted to expand the pipe while pressurizing an end surface of the pipe on the inserting side in an axial direction of the pipe. 2. A pipe expanding method for expanding a pipe by inserting a pipe expanding punch from an end portion of the pipe of a heat exchanger having a plurality of laminated fins and a pipe penetrating the fins, the pipe expanding punch comprising: The end face of the pipe on the inserting side is expanded by inserting the expansion pipe punch while pressurizing the end face of the pipe in the axial direction of the pipe by the flare process part, and flaring the end part of the pipe by the flare process part. Expansion method. 3. The pipe expanding method according to claim 1, wherein the means for pressurizing the end surface of the pipe is a pressure punch driven by a servomotor. 4. The pipe expanding method according to claim 1, wherein the means for pressurizing the end surface of the pipe is a pressure punch driven by a hydraulic cylinder. 5. The pipe expanding method according to claim 1, wherein the means for pressurizing the end surface of the pipe is a pressurizing punch driven by gravity of a weight. 6. A pipe expanding device for expanding a pipe of a heat exchanger comprising a plurality of laminated fins and pipes penetrating the fins, wherein the pipe is inserted from an end portion of the pipe into the pipe. A punch, a pressure punch that abuts the end face of the pipe on the side where the tube expansion punch is inserted, and the tube expansion punch and the pressure punch are advanced in synchronization with each other,
A pressurizing drive mechanism for inserting the pipe expanding punch and expanding the pipe while pressurizing an end face of the pipe in an axial direction of the pipe. 7. The tube expanding device according to claim 6, wherein the pressure punch is a flare processing section. 8. The tube expanding device according to claim 6, wherein the pressurizing drive mechanism is a servo motor.