JPH08313183A - Heat exchanger and manufacture of corrugated fin therefor - Google Patents

Abstract

PURPOSE: To enable manufacturing without positioning slits with respect to valley parts of corrugated fins by arranging the corrugated fins inside or outside a tube to be bent in a corrugation with ridge parts repeated and providing the slits piercing the corrugated fins across the thickness thereof. CONSTITUTION: Two molded plates made of a metal alloy are joined as opposed to each other to form a flat tube 2 in a shape of a flat pipe and corrugated fins 3 and 10 are arranged inside or outside the flat tube 2 to be bent in a sinusoidal shape with ridge parts repeated. Rectangular slits are formed at a plurality of locations of the corrugated fin 10 as through holes piercing four ridge parts 15 and four bottom wall parts 14 in the direction of a square wave of the corrugation. This enables manufacturing without positioning slits with respect to the valley parts of the corrugated fins 3 and 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for cooling supercharged air heated by a supercharger by exchanging heat with cooling air or cooling water, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as the demand for higher output of automobiles increases, the number of automobiles equipped with a supercharger tends to increase.
In addition, in order to achieve the purpose of further increasing the engine output, the number of vehicles equipped with air-cooled heat exchangers (hereinafter referred to as intercoolers) that cool the supercharged air that has become hot by the supercharger is on the rise. is there. Under such circumstances, along with the improvement in the performance of the supercharger, there is a growing demand for higher performance of the intercooler, that is, higher heat dissipation and lower pressure loss.

It is known that the high performance of the intercooler is achieved by the effect of increasing the heat transfer area by the inner fins arranged in the tube through which the supercharged air flows. However, depending on the shape of the inner fin,
There is a problem that the pressure loss of the supercharging air increases, the supercharging pressure decreases, the intake air weight supplied to the combustion chamber of the engine decreases, and the engine performance deteriorates.

There is known an intercooler in which a high-performance inner fin is inserted in a tube in order to improve performance (conventional example: JP-A-3-45891 and JP-A-3-8).
4396). In the inner fin 100 of this intercooler, as shown in FIG. 8, a mountain portion 101 bent in a rectangular wave shape has a bottom wall portion 102 and a side wall portion 10.
3, the ceiling wall portion 104 and the side wall portion 105, and penetrates in the plate thickness direction through a slit 106 that is formed by vertically cutting the side wall portion 103 from a portion of the bottom wall portion 102 and cutting it to a portion of the ceiling wall portion 104. ing.

The conventional inner fin 100 is
As shown in FIG. 9, the slit 106 is formed in the thin metal plate 107.
(A), a corrugating step (b) of bending the metal thin plate 107 into a rectangular wave shape, and a step of cutting the rectangular metal thin plate 107 into a predetermined length to manufacture the inner fin 100. Press molding is performed one by one by a press molding machine in the order of step (c). That is, according to the conventional molding method, the slit 106 for the mountain portion 101 is formed.
Since it is necessary to align the positions of the metal thin plates 107 one by one, the metal fins 107 are sent to the next step,
0 is manufactured.

[0006]

However, in the future automobile industry, an automobile with even better performance is required, and a large amount of excellent parts constituting the automobile is required. Therefore, the productivity of inner fins is further improved. Improvement is desired. Therefore, for the purpose of improving the productivity, the metal thin plate of the inner fin 100 should not be aligned with the position of the slit 106 with respect to the ridge 101 after the slit 106 is drilled in the metal thin plate, and the metal thin plate should be rectangular wave-shaped using a high-speed press molding machine. It is possible to bend it into a shape.

In this case, as shown in FIG. 10 for the one in FIG.
The position of 6 is displaced. When the inner fin 100 shown in FIG. 10 is inserted into the tube of the intercooler, the heat radiation amount of the supercharged air does not change as compared with that of FIG. 8, but the pressure loss of the supercharged air of FIG. 1 compared to the one
It has been confirmed by experiments that the increase is 6%.

Therefore, if the thin metal plate 107 is bent into a rectangular wave shape without aligning the positions of the slits 106 with respect to the ridges 101, those shown in FIG.
0 has an inner fin shape, and the one in FIG. 10 has a pressure loss ratio of 100 to 1 compared to that in FIG.
There is a problem in that it will vary up to 16.

Here, in order to improve the productivity, it is considered that the metal thin plate 107 is continuously bent into a rectangular wave shape by using a gear-shaped roller. That is, the slits 106 arranged in the longitudinal direction of the thin metal plate 107 are arranged.
Is used as a pilot hole, or a pilot hole is newly provided next to the slit 106, and the pilot pin provided on the outer periphery of the roller is fitted into the pilot hole, whereby the position of the slit 106 with respect to the mountain portion 101 is increased. It is also possible to manufacture the inner fin 100 while aligning. However, since the metal thin plate 107 has a thin plate thickness of 0.08 mm, the edge portion of the pilot hole for positioning is pulled by the pilot pin and a crack is formed around the pilot hole, resulting in a defective product. There was a problem of becoming.

An object of the present invention is to provide a heat exchanger capable of being manufactured without aligning the positions of the slits with respect to the peaks of the corrugated fins, thereby further improving the productivity of the corrugated fins, and the heat exchange. It is to provide a method for manufacturing a corrugated fin for dexterity. Also,
To provide a heat exchanger capable of reducing the variation in pressure loss of the first fluid or the second fluid that flows so as to sew the corrugated fins without aligning the positions of the slits with respect to the peaks of the corrugated fins. It is in. It is another object of the present invention to provide a heat exchanger capable of suppressing the generation of defective products when manufacturing corrugated fins, and a method of manufacturing corrugated fins for heat exchangers.

[0011]

According to a first aspect of the present invention, there is provided a tube for exchanging heat between a first fluid flowing inside and a second fluid flowing outside, and a tube arranged inside or outside the tube. A heat exchanger comprising a corrugated fin that is bent in a wave shape by repeating parts and a slit that penetrates in the plate thickness direction of the corrugated fin, wherein the slit is continuous over two or more ridges. The technical means formed by

The invention according to a second aspect is characterized in that, in addition to the heat exchanger according to the first aspect, the slits are provided at a plurality of positions at predetermined intervals in the width direction of the corrugated fins. . According to the invention described in claim 3, in addition to the heat exchanger according to claim 1 or 2,
It is characterized in that the corrugated fins are provided at a plurality of positions at predetermined intervals in the longitudinal direction.

According to a fourth aspect of the present invention, in addition to the heat exchanger according to any one of the first to third aspects, the corrugated fins are arranged in the longitudinal direction of the tube or substantially in the longitudinal direction. It is characterized in that it is formed in a rectangular wave shape so as to be along the direction orthogonal to each other. According to a fifth aspect of the present invention, in addition to the heat exchanger according to any one of the first to third aspects, the corrugated fins are provided in a longitudinal direction of the tube or in a direction substantially orthogonal to the longitudinal direction. It is characterized in that it is formed in a sine wave shape so as to follow the.

According to a sixth aspect of the present invention, in the heat exchanger according to any of the first to fifth aspects, the step of making the slits in the thin plate-shaped material, the slits and the ridges. The technical means including a roller forming step in which the thin plate-shaped material is passed between a pair of gear-shaped rollers and continuously bent into a corrugated shape without performing alignment with the parts.

[0015]

According to the invention described in claim 1, since the slits are continuously formed over two or more ridges of the corrugated fin, the position of the slits relative to the ridges is temporarily determined. Even if the corrugated fins are manufactured without matching, the slit shapes of the (n-1) peaks are always the same shape. That is, 1 / (n-1)
Since only the slit shape of the crests for each piece varies, it is possible to reduce the variation in pressure loss of the first fluid or the second fluid that flows so as to sew the corrugated fins.

According to the second aspect of the present invention, the corrugated fins flow in a sewn manner by the plurality of slits and the plurality of peaks formed at a predetermined interval (pitch) in the width direction of the corrugated fins. Since the first fluid or the second fluid is forcibly disturbed, the heat exchange performance with the second fluid or the first fluid is improved.

According to the third aspect of the invention, the corrugated fins flow in a sewn manner by the plurality of slits and the plurality of peaks formed at a predetermined interval (pitch) in the longitudinal direction of the corrugated fins. Since the first fluid or the second fluid is forcibly disturbed, the heat exchange performance with the second fluid or the first fluid is improved.

According to the fourth aspect of the present invention, since the corrugated fins are formed in a rectangular wave shape, the contact area between the corrugated fins and the tube is increased. This facilitates heat transfer between the tube and the corrugated fin. Further, when the louver is provided on the corrugated fin, the louver cut length can be extended. Furthermore, since a large number of fluid passages are formed in the flow direction of the first fluid or the second fluid, the heat exchange performance with the second fluid or the first fluid is improved.

According to the fifth aspect of the invention, since the corrugated fin is formed in a sinusoidal shape, it is easy to manufacture. Further, the spring action of the mountain portion of the corrugated fin facilitates controlling buckling of the corrugated fin when the corrugated fin and the tube are laminated and the core is assembled. Furthermore, since a large number of fluid passages are formed in the flow direction of the first fluid or the second fluid, the heat exchange performance with the second fluid or the first fluid is improved.

According to the invention described in claim 6, after the slit is formed in the thin plate-shaped material, the thin plate-shaped material is formed into a pair of gears without aligning the slit and the mountain portion. Pass it between the rollers and bend it into a wavy shape,
Manufactures corrugated fins. Therefore, when manufacturing the corrugated fins, it is not necessary to align the positions of the slits with respect to the ridges, and therefore the molding speed of the corrugated fins can be increased, so that the productivity of the corrugated fins can be further improved. Further, it is not necessary to provide pilot pins on the pair of gear-shaped rollers, and it is not necessary to provide pilot holes on the thin plate-shaped material. As a result, the pilot pin does not cause cracks in the pilot hole, so that it is possible to prevent defective products from being produced when the corrugated fin is manufactured.

[0021]

Next, the heat exchanger according to the present invention will be described based on an embodiment applied to an air-cooling type intercooler.

[Structure of First Embodiment] FIGS. 1 to 6 show a first embodiment of the present invention. FIG. 1 is a view showing an inner fin for an intercooler, and FIG. 2 is an air-cooling type. FIG. 3 is a view showing an intercooler, and FIG. 3 is a view showing a main part of the air-cooled intercooler.

The air-cooling type intercooler 1 is mounted, for example, in front of the engine room of an automobile, and cools the supercharged air, which has become high temperature and high pressure by a supercharger, by exchanging heat with cooling air (atmosphere). Is a laminated heat exchanger. The air-cooling type intercooler 1 has a plurality of flat tubes 2 and outer fins 3 alternately laminated, which are formed in a flat tube shape by joining and facing two metal alloy molding plates mainly made of aluminum. Is configured.

The outer fin 3 is a corrugated fin having a sinusoidal shape for increasing the amount of heat released from the supercharged air supplied from the supercharger (improving heat exchange efficiency). A large number of louvers 4 are formed on the outer fin 3 in order to further improve the heat exchange efficiency.

The flat tube 2 has an inlet tank portion 5 and an outlet tank portion 6 on both end sides, and a heat exchange portion 7 connecting the inlet tank portion 5 and the outlet tank portion 6 between them. There is. The inlet tank part 5 is joined to a suction pipe 8 connected to a supercharger (not shown). The outlet tank portion 6 is joined to a discharge pipe 9 connected to an intake pipe (not shown) of the engine. In addition, the plurality of flat tubes 2, the plurality of outer fins 3, the suction pipe 8 and the discharge pipe 9 are joined by using a means such as brazing.

An inner fin 10 is provided in the heat exchange portion 7 of the flat tube 2 to increase the heat radiation amount of the supercharged air supplied from the supercharger (improve the heat exchange efficiency).
Also, the pressure loss of supercharged air is reduced. The inner fin 10 is made of a metal alloy plate mainly made of aluminum and has a plate thickness of 0.08 mm, and is provided in the heat exchange portion 7 so as to have a rectangular wave shape in a direction orthogonal to the flow direction of the supercharged air. Has been inserted.

The inner fins 10 are the corrugated fins for the heat exchanger according to the present invention, and the side walls 11 are provided in parallel.
12, a top wall portion 13 that connects one end portions (upper end portions) of the adjacent side wall portions 11 and 12 to each other, and a bottom wall portion 14 that connects the other end portions (lower end portions) of the adjacent side wall portions 11 and 12 to each other It consists of The inner fin 10 has the side wall portion 1
1, 12, the top wall portion 13 and the bottom wall portion 14 are formed in a rectangular wave shape by continuously providing a large number in the width direction of the flat tube 2. In addition, the side wall portions 11 and 1 which are adjacently provided
2 and one end portion (upper end portion) of these side wall portions 11 and 12
The inner fin 1 is formed by the top wall portion 13 connecting the inner fins to each other.
A mountain portion 15 of 0 is formed.

The side walls 11 and 12 extend in the width direction of the flat tube 2 and have a predetermined fin pitch P (for example, 1.7).
mm) are arranged alternately. The side wall portions 11 and 12
Is a vertical wall portion arranged in parallel in the height direction of the inner fin 10 at a predetermined interval, and divides the inside of the heat exchange portion 7 into a plurality of fluid passages in the width direction of the flat tube 2. In addition, in order to further improve the heat exchange performance (heat dissipation performance) by the inner fin 10, a large number of louvers may be formed on the side wall portions 11 and 12.

The top wall portion 13 and the bottom wall portion 14 are extended in the width direction of the flat tube 2, and are brought into contact with the inner side surfaces of the respective molding plates of the flat tube 2 and joined by means such as brazing. There is. In addition, the fin width B of the inner fin 10 (side wall portions 11 and 12, the top wall portion 13, and the bottom wall portion 14) is, for example, 80 mm to 120 mm.
The height H of the (side wall portions 11, 12) is, for example, 3.8 mm.

In the inner fin 10 of this embodiment, a rectangular slit (oblong hole) is formed as a through hole that penetrates the four peak portions 15 and the four bottom wall portions 14 in the rectangular wave direction in the plate thickness direction. 16, 17 are formed at a plurality of locations. That is, the slits 16 and 17 are formed such that the second to fourth peak portions 15 and the first to fourth peaks are formed from the center of the top wall portion 13 of the first peak portion 15.
Through the bottom wall portion 14 to the center of the top wall portion 13 of the fifth mountain portion 15.

As shown in FIG. 1, the slit 16 is the end of two adjacent slits 17 (slit 17).
A start end (one end in the longitudinal direction of the slit 16) 16a is provided on the same plane as the other end 17b in the longitudinal direction of the slit 16b, and the start ends of the two adjacent slits 17 (one end in the longitudinal direction of the slit 17) 17a. End on the same plane as (slit 16
16b) is provided. The slit width S of the slits 16 and 17 is, for example, 2.8.
The fin cut length L is 14 mm, for example.

[Manufacturing Apparatus of First Embodiment] Next, a fin manufacturing apparatus for manufacturing the inner fin 10 for the intercooler will be described with reference to FIG.

The fin manufacturing apparatus 20 comprises a press molding machine 2
1 and a pair of forming rollers 22, 23 and the like. The press molding machine 21 includes a fixed die 24 and a movable die 25 that moves up and down with respect to the fixed die 24.
The slits 16 and 17 are formed in the thin plate-shaped metal material 40. The outer surfaces of the pair of forming rollers 22 and 23 are gear-shaped, and the thin metal material 40 is formed into a wave shape.

[Manufacturing Method of First Embodiment] Next, a manufacturing method of the air-cooling type intercooler 1 will be briefly described with reference to FIGS. 4 to 6.

First, a method of forming the inner fin 10 will be described. A thin plate-shaped metal material (aluminum alloy plate) 40 having a plate thickness of 0.08 mm, for example, is fed into the fixed mold 24 of the press molding machine 21, and the movable mold 25 is lowered to form a hole. A plurality of slits 16 and 17 are formed at predetermined positions of the metal material 40 (step of making a hole).

Next, a thin plate-shaped metal material 40 with holes
Is sent between the pair of molding rollers 22 and 23, and the gears provided on the pair of molding rollers 22 and 23 do not align the positions of the slits 16 and 17 with the crests 15 to form a thin plate shape. The metal material 40 is formed into a wave shape (roller forming step). At this time, the fin pitch between the adjacent mountain portions 15 is, for example, 6 mm.

Next, the corrugated metal material 40 is fed between the pair of feed rollers 26 and 27, and the pair of feed rollers 2 is fed.
Further, it is sent to the friction brake 28 by 6, 27 and the corrugated metal material 40 is bent into a rectangular corrugated shape (roller molding step). At this time, as shown in FIGS. 5 and 6, the fin pitch between the adjacent mountain portions 15 is, for example, 1.7.
mm.

As described above, when forming the inner fin 10 of this embodiment, the slits 16 and 17 are not aligned with the ridges 15, so the slits 16 and 17 are not aligned with the ridges 15. The position of 17 becomes random, and when such an inner fin 10 is inserted into the flat tube 2 and assembled as the intercooler 1, the pressure loss for each product varies. However, as in this embodiment, the slits 16 and 17 of the inner fin 10 are
By making the long holes of four peaks 15 minutes, three peaks 15 minutes always have the same shape, and one peak 1
Only 5 minutes will change the beginning and end of the hole.

That is, since only the shape of the ridge portion 15 of the inner fin 10 is varied, the variation in pressure loss as a whole is reduced. After that, the rectangular wave-shaped metal material 40 is cut into a predetermined length (cutting step), and thus the rectangular wave-shaped inner fin 10 as shown in FIG. 1 is manufactured.

Next, the inner fins 10 are inserted into a plurality of flat tubes 2 formed by pressing a metal alloy plate mainly made of aluminum into a predetermined shape. At this time, by using a brazing sheet whose both sides are coated with a brazing filler metal as a material of the flat tube 2, the brazing filler metal is applied to the inner surface of the flat tube 2 and the inner fin 1.
Therefore, it is possible to save the trouble of disposing the brazing filler metal between the outer wall surface of the top wall portion 13 and the outer surface of the bottom wall portion 14.

Next, a plurality of flat tubes 2 having inner fins 10 inserted therein and outer fins 3 are alternately laminated, and further the outermost flat tubes 2 arranged on the outermost side.
As shown in FIG. 2, the assembled body in which the suction pipe 8 and the discharge pipe 9 are inserted into the circular hole of FIG.
And the air-cooled intercooler 1 as shown in FIG. 3 is manufactured.

[Operation of First Embodiment] Next, the operation of the air-cooling type intercooler 1 will be briefly described with reference to FIGS. 1 to 3.

The supercharged air which has become high temperature and high pressure due to the operation of the supercharger flows from the suction pipe 8 into the heat exchanging portion 7 through the inlet tank portions 5 of the plurality of flat tubes 2, and a large number of inner fins 10 are provided. Mountain portion 15 and a plurality of slits 16, 17
Is disturbed by. The supercharged air is supplied from the side wall portions 11 and 12 of the inner fin 10 to the top wall portion 13 and the bottom wall portion 1.
4, the flat tubes 2, the outer fins 3 are radiated to the cooling air to dissipate the heat, and the cooling air is cooled and is then drawn into the intake pipe of the engine through the outlet tank portion 6 and the discharge pipe 9.

[Effects of the First Embodiment] As described above, the air-cooling type intercooler 1 is provided with the slits 16 and 17 of the inner fin 10 which are four holes 15 minutes long, thereby forming the peaks. Even if the inner fin 10 is formed without positioning the positions of the slits 16 and 17 with respect to 15, and the positions of the slits 16 and 17 are random with respect to the position of the peak portion 15, 1 / (4 peaks There is a variation in the position of only the portion 15-1).

Therefore, since the variation can be suppressed as a whole as a whole, the variation in the pressure loss of the supercharged air can be reduced. As a result, a large increase in the pressure loss of the supercharged air can be suppressed, so that the decrease in the supercharged pressure and the decrease in the intake air weight supplied to the combustion chamber of the engine can be suppressed. Can be suppressed.

Since the forming speed of the inner fin 10 can be increased, the productivity of the inner fin 10 can be improved, which can contribute to the improvement of the productivity of the air-cooling type intercooler 1 and reduce the manufacturing cost. You can
Therefore, even if the number of automobiles equipped with a supercharger increases, it becomes possible to sufficiently cope with the situation. Moreover, since the price of the air-cooled intercooler 1 can be reduced, the price of a vehicle equipped with a supercharger can be suppressed.

Further, when the inner fin 10 is formed into a rectangular wave shape, the slits 16 and 17 with respect to the peak portion 15 are formed.
Since it is not necessary to align the positions of 1 and 2, it is not necessary to provide pilot pins on the outer peripheral surfaces of the pair of forming rollers 22 and 23, and it is not necessary to provide pilot holes in the metal material 40 of the inner fin 10. As a result, the pilot pin does not cause cracks in the pilot hole, so that defective products can be suppressed when the inner fin 10 is formed into a rectangular wave shape.

[Second Embodiment] FIG. 7 shows a second embodiment of the present invention and is a view showing an inner fin for an intercooler.

In the inner fin 10 of this embodiment, an elliptic slit 16 and an elliptic slit 17 are lapped (overlapped), and the slits 16, 1
The starting ends 16a and 17a and the ending ends 16b and 17b of No. 7 are semicircular holes. That is, the slits 16, 1
No. 7 is the fifth from the one end of the top wall portion 13 of the first mountain portion 15 through the second to fourth mountain portions 15 and the first to fourth bottom wall portions 14.
It is open to the other end of the top wall portion 13 of the mountain portion 15. The slit 16 is provided with a starting end 16a at an intermediate portion between a starting end 17a and a terminating end 17b of two adjacent slits 17, and an ending end 16b at an intermediate portion between an terminating end 17b and a starting end 17a of the two adjacent slits 17. Is provided.

[Modification] In this embodiment, a laminated heat exchanger was used as the heat exchanger, but a round tube / plate fin type heat exchanger or a deformed tube / corrugated fin type heat exchanger was used as the heat exchanger. You may use a container. Further, the present invention may be applied to other heat exchangers such as an oil cooler, an evaporator, a condenser, a radiator or a heater core. Further, the air-cooled intercooler 1 may be replaced with a water-cooled heat exchanger.

Although the present invention is applied to the inner fin 10 in this embodiment, the present invention may be applied to the outer fin. Further, in this embodiment, the rectangular fin-shaped inner fin 10 is used as the heat exchanger corrugated fin, but a sinusoidal, arcuate, or corrugated corrugated fin may be used as the heat exchanger corrugated fin. . Further, the shape of the slit is not limited to a rectangular shape or an elliptical shape, but may be a circular shape, an elliptical shape, an egg shape, a triangular shape, a square shape, a trapezoidal shape, a polygonal shape, or the like.

[Brief description of drawings]

FIG. 1 is an enlarged partial perspective view of an inner fin (first embodiment).

FIG. 2 is a perspective view showing an air-cooled intercooler (first embodiment).

FIG. 3 is an enlarged sectional view of a main part of an air-cooled intercooler (first embodiment).

FIG. 4 is a schematic view showing a fin manufacturing apparatus (first embodiment).

FIG. 5 is a plan view showing the manufacturing process of the inner fin (first embodiment).

FIG. 6 is a sectional view taken along line AA of FIG. 5 (first embodiment).

FIG. 7 is an enlarged partial perspective view of an inner fin (second embodiment).

FIG. 8 is an enlarged partial perspective view of an inner fin (conventional example).

FIG. 9 is a perspective view showing a manufacturing process of an inner fin (conventional example).

FIG. 10 is an enlarged partial perspective view of an inner fin (conventional example).

[Explanation of symbols]

 1 Air-cooled intercooler (heat exchanger) 2 Flat tube 10 Inner fin (corrugated fin for heat exchanger) 15 Mountain part 16 Slit 17 Slit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masakazu Hyodo 1-1, Showa-cho, Kariya city, Aichi Prefecture Nihondenso Co., Ltd.

Claims (6)

[Claims] 1. A first fluid flowing inside and a second fluid flowing outside.
Heat provided with a tube for exchanging heat with the fluid, a corrugated fin arranged inside or outside of the tube and bent in a wavy shape by repeating peaks, and a slit penetrating in the plate thickness direction of the corrugated fin. It is an exchanger, Comprising: The said slit was continuously formed over two or more peak parts, The heat exchanger characterized by the above-mentioned. 2. The heat exchanger according to claim 1, wherein the slits are provided at a plurality of positions at predetermined intervals in the width direction of the corrugated fin. 3. The heat exchanger according to claim 1 or 2, wherein the slits are provided at a plurality of positions at predetermined intervals in the longitudinal direction of the corrugated fins. 4. The heat exchanger according to claim 1, wherein the corrugated fins extend in the longitudinal direction of the tube.
Alternatively, the heat exchanger is formed in a rectangular wave shape along a direction substantially orthogonal to the longitudinal direction. 5. The heat exchanger according to claim 1, wherein the corrugated fins extend in the longitudinal direction of the tube.
Alternatively, the heat exchanger is formed in a sine wave shape along a direction substantially orthogonal to the longitudinal direction. 6. The heat exchanger according to any one of claims 1 to 5, wherein (a) a step of making the slit in a thin plate-shaped material, and (b) the slit and the mountain portion. A corrugate for a heat exchanger, which comprises a roller forming step in which the thin plate-shaped material is passed between a pair of gear-shaped rollers and continuously bent into a wavy shape without performing alignment with Fin manufacturing method.