HEAT EXCHANGER, AND METHOD FOR MANUFACTURING HEAT EXCHANGER

TECHNICAL FIELD

The present disclosure relates to a heat exchanger and a method of fabricating a heat exchanger.

BACKGROUND ART

Some heat exchangers include partially bent headers for distributing or gathering refrigerant to or from heat transfer pipes. The partially bent headers can be readily installed in apparatuses. Such a heat exchanger is fabricated by providing heat transfer pipes and fins to linearly extending headers, and then bending these headers. The step of bending the headers may unintentionally deform the fins in this heat exchanger. To avoid deformation of the fins, heat exchangers capable of avoiding deformation of the fins have been developed.

For example, Patent Literature 1 discloses a heat exchanger including two types of fins having different depths, in the gaps between heat transfer pipes arranged adjacent to the bent sections of headers. The two types of fins are alternately arranged in the arrangement direction of the heat transfer pipes.

Patent Literature 1 describes that the two types of fins having different depths can avoid significant deformation and breakage of fins in the bending step of the process of fabricating the heat exchanger.

CITATION LIST
Patent Literature

Patent Literature 1: International Publication No. WO 2015/027680

SUMMARY OF INVENTION
Technical Problem

The bending step, however, applies a compressive force to the inner side of bending of the headers, regardless of avoidance of deformation of the fins. The bending step may thus cause deformation of the heat transfer pipes disposed adjacent to the bent sections of the headers.

The deformation of the heat transfer pipes may narrow or close the internal flow paths of the heat transfer pipes. This phenomenon may lead to a decrease in the heat exchange efficiency.

An objective of the present disclosure, which has been accomplished to solve the above problem, is to provide a heat exchanger and a method of fabricating a heat exchanger that can avoid deformation of heat transfer pipes disposed adjacent to bent sections of headers and avoid a decrease in the heat exchange efficiency.

Solution to Problem

In order to achieve the above objective, a heat exchanger according to the present disclosure includes: a first header having a first bent section; a second header having a second bent section bent in the same direction as the first bent section and opposed to the first bent section; first heat transfer pipes arranged along the first bent section and connecting the first bent section and the second bent section; and fins that are to transfer heat from the first heat transfer pipes and that are each disposed between adjacent two of the first heat transfer pipes. At least one fin of the fins has a weak portion, the weak portion of each of the at least one fin has a lower rigidity than other portions of the fin, and the weak portion is more readily deformed than the other portions in response to a change in the distance between the adjacent two of the first heat transfer pipes.

Advantageous Effects of Invention

In the heat exchanger according to the present disclosure, at least one fin of the fins has a weak portion, the weak portion of each of the at least one fin has a lower rigidity than the other portions of the fin, and the weak portion is more readily deformed than the other portions in response to a change in the distance between the adjacent two of the first heat transfer pipes. That is, when the distance between the first heat transfer pipes changes in a bending step of providing the first bent section and the second bent section to the first header and the second header, the weak portion of the fin is deformed earlier than the other portions of the fin. These features can avoid deformation of the first heat transfer pipes. The avoidance of deformation of the first heat transfer pipes leads to avoidance of a decrease in the heat exchange efficiency of the heat exchanger.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a heat exchanger according to Embodiment 1 of the present disclosure;

FIG. 2 is an enlarged perspective view of an area II illustrated in FIG. 1 when the area II is viewed from the rear side;

FIG. 3 is an enlarged perspective view of a fin fixed to heat transfer pipes coupled to bent sections of headers included in the heat exchanger according to Embodiment 1 of the present disclosure;

FIG. 4 is a sectional view of the fins vertically overlapping with the bent sections of the heat exchanger according to Embodiment 1 of the present disclosure;

FIG. 5 is a flowchart illustrating a method of fabricating a heat exchanger according to Embodiment 1 of the present disclosure;

FIG. 6 is a front view of multiple heat transfer pipes that hold fins and unprocessed fins therebetween in a step of building a semifinished heat exchanger involved in the method of fabricating a heat exchanger according to Embodiment 1 of the present disclosure;

FIG. 7 is a front view of a semifinished heat exchanger fabricated in the step of building a semifinished heat exchanger involved in the method of fabricating a heat exchanger according to Embodiment 1 of the present disclosure;

FIG. 8 is an enlarged rear view illustrating a part of a modification of the heat exchanger according to Embodiment 1 of the present disclosure, which includes warped heat transfer pipes;

FIG. 9 is an enlarged perspective view illustrating a part of heat transfer pipes and a fin included in a heat exchanger according to Embodiment 2 of the present disclosure;

FIG. 10 is an enlarged perspective view illustrating a part of a modification of the heat exchanger according to Embodiment 2 of the present disclosure;

FIG. 11 is an enlarged perspective view illustrating a part of another modification of the heat exchanger according to Embodiment 2 of the present disclosure;

FIG. 12 is an enlarged perspective view illustrating a part of heat transfer pipes and a fin included in a heat exchanger according to Embodiment 3 of the present disclosure;

FIG. 13 is an enlarged perspective view illustrating a part of a modification of the heat exchanger according to Embodiment 3 of the present disclosure;

FIG. 14 is an enlarged sectional view illustrating a part of a fin included in a heat exchanger according to Embodiment 4 of the present disclosure;

FIG. 15 is an enlarged perspective view illustrating a part of heat transfer pipes and a fin included in a heat exchanger according to Embodiment 5 of the present disclosure;

FIG. 16 is a development view of a modification of the heat exchanger according to Embodiment 1 of the present disclosure;

FIG. 17 is a development view of another modification of the heat exchanger according to Embodiment 1 of the present disclosure; and

FIG. 18 is a sectional view of fins included in still another modification of the heat exchanger according to Embodiment 1 of the present disclosure.

DESCRIPTION OF EMBODIMENTS

A heat exchanger and a method of fabricating a heat exchanger according to embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. In the drawings, the components identical or corresponding to each other are provided with the same reference symbol. The drawings are provided with an orthogonal coordinate system XYZ. In this coordinate system, the Z axis corresponds to the vertical direction in which the pipe axes of multiple heat transfer pipes included in the heat exchanger extend. The X axis corresponds to the horizontal direction in which the heat transfer pipes are arranged. The Y axis is orthogonal to the Z and X axes. The following description refers to this coordinate system as required.

Embodiment 1

A heat exchanger according to Embodiment 1 includes fins that are coupled to bent sections of headers and have weak portions, in order to avoid deformation of heat transfer pipes. The following describes a structure of the heat exchanger, focusing on an example in which this heat exchanger is applied to an outdoor unit of an air-conditioning apparatus. The entire structure of the heat exchanger is described below with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view of a heat exchanger 1A according to Embodiment 1. FIG. 2 is an enlarged perspective view of an area II illustrated in FIG. 1 when the area II is viewed from a rear side B. FIG. 1 illustrates only heat transfer pipes 20 and fins 30 located in a part of the heat exchanger 1A, without the heat transfer pipes 20 and the fins 30 located in other parts, in order to facilitate an understanding. FIG. 2 illustrates only three heat transfer pipes 20 adjacent in the horizontal direction and two fins 30 disposed therebetween.

As illustrated in FIG. 1, the heat exchanger 1A includes headers 11 and 12 for distributing and gathering refrigerant, multiple heat transfer pipes 20 that are coupled to the headers 11 and 12 and allow the refrigerant to flow therein, and multiple fins 30 fixed to the heat transfer pipes 20.

The headers 11 and 12 have a shape of rectangular tube. The headers 11 and 12 define internal flow paths, which are not illustrated. The headers 11 and 12 respectively have joint sections 13 and 14 having a shape of circular pipe, which are illustrated in FIG. 1. The joint sections 13 and 14 are coupled to connecting tubes of external apparatuses, which are not illustrated, for feeding or discharging refrigerant. The headers 11 and 12, which are connected to the external apparatuses, allow refrigerant to flow in the internal flow paths.

The headers 11 and 12 are arranged apart from each other in the vertical direction, such that the pipe axes A1 and A2 extend in the horizontal direction, as illustrated in FIG. 1. The headers 11 and 12 are coupled to the heat transfer pipes 20 to allow refrigerant to circulate therebetween.

The heat transfer pipes 20 have a tubular shape in which refrigerant flows. The heat transfer pipes 20 extend in the vertical direction. The upper and lower ends of the heat transfer pipes 20 are inserted in insertion holes, which are not illustrated, on the walls of the rectangular cylinders of the headers 11 and 12. The heat transfer pipes 20 are thus coupled to the headers 11 and 12. The heat transfer pipes 20 having this structure allow the refrigerant flowing in the headers 11 and 12 to circulate in the heat transfer pipes 20.

The heat transfer pipes 20 are made of a metal having a high thermal conductivity, such as pure aluminum or aluminum alloy, so as to facilitate heat conduction of the refrigerant circulating in the heat transfer pipes 20. The heat transfer pipes 20 have a flattened circular section, which also contributes to heat conduction of the refrigerant. That is, the heat transfer pipes 20 are flat pipes. The heat transfer pipes 20 are arranged with a certain pitch along the pipe axes of the headers 11 and 12, as illustrated in FIG. 1. The heat transfer pipes 20 have gaps therebetween. These gaps accommodate the fins 30 for radiating, to the ambient air, the heat transferred to the heat transfer pipes 20.

The fins 30 are made of a metal having a high thermal conductivity, for example, the metal identical to the material of the heat transfer pipes 20, so as to facilitate heat conduction from the heat transfer pipes 20. The fins 30 have a plate shape, as illustrated in FIG. 2, which contributes to radiation of the heat to the ambient air. These plate-like fins 30 are repetitively bent into a shape of corrugation. The fins 30 are each held between adjacent heat transfer pipes 20 such that the mountain portions and the valley portions of the corrugation are oriented toward the flat surfaces of the heat transfer pipes 20. The mountain portions and the valley portions of the corrugation defined by the fin 30 are bonded to the corresponding heat transfer pipes 20. The fins 30 are thus fixed to the heat transfer pipes 20. The fins 30 having this structure radiate the heat transferred from the heat transfer pipes 20, from the surfaces of the corrugated plate to the ambient air.

Referring back to FIG. 1, the headers 11 and 12 are bent into an L-shape suitable for being accommodated in a rectangular parallelepiped housing of the outdoor unit. In detail, the headers 11 and 12 respectively have L-shaped bent sections 15 and 16 bent at a right angle, and linear sections 17 and 18 linearly extending from the bent sections 15 and 16.

The bent sections 15 and 16 are formed by, after building a semifinished heat exchanger including linearly extending headers 11 and 12, bending this semifinished heat exchanger. This bending step applies a compressive force to the inner side of bending of the semifinished heat exchanger, which may unintentionally deform the fins 30 into irregular shapes. These fins 30 having irregular shapes have different ventilation resistances, and may lead to a decrease in the heat exchange efficiency of the heat exchanger 1A.

The compressive force applied in the bending step may also deform the heat transfer pipes 20 and thus narrow or close the internal flow paths of the heat transfer pipes 20. Such deformation may lead to a decrease in the heat exchange efficiency of the heat exchanger 1A.

To avoid irregular deformation of the fins 30, and to avoid deformation of the heat transfer pipes 20 with higher propriety than that of deformation of the fins 30, the method of fabricating the heat exchanger 1A involves a step of bending the fins 30 at certain sites. Specifically, the fins 30 disposed adjacent to the bent sections 15 and 16 have weak portions at certain sites, which have a lower rigidity and are more readily deformed in response to bending than the other portions.

The following describes structures of fins 40A and weak portions, with reference to FIGS. 3 and 4. The fins 40A hereinafter indicate the fins 30 disposed adjacent to the bent sections 15 and 16, in order to facilitate an understanding.

FIG. 3 is an enlarged perspective view of a fin 40A fixed to the heat transfer pipes 20 coupled to the bent sections 15 and 16 of the headers 11 and 12. FIG. 4 is a sectional view of the fins 40A vertically overlapping with the bent sections 15 and 16 of the heat exchanger 1A. FIG. 3 is an enlarged perspective view of an area IV illustrated in FIG. 1 when the area IV is viewed from the rear side B. FIG. 4 does not illustrate the internal structures of the heat transfer pipes 20, in order to facilitate an understanding.

As illustrated in FIG. 3, the fin 40A is repetitively bent into a corrugated plate having a shape of vertically arranged waves, like the fin 30. The mountain portions 401 of the corrugation in contact with the heat transfer pipe 20 on the +X side, and valley portions 402 in contact with the heat transfer pipe 20 on the −X side. The mountain portions 401 and the valley portions 402 are connected to each other with plate segments 41. In other words, the fin 40A has multiple plate segments 41 that extend from one to the other of two adjacent heat transfer pipes 20 across the gap between the heat transfer pipes 20.

Such fins 40A are fixed to the heat transfer pipes 20 disposed adjacent to the bent sections 15 and 16 of the headers 11 and 12. The fins 40A are each provided with weak portions in the plate segments 41.

This specification defines the weak portions as portions of the plate segments 41 of the fin 40A that have a lower rigidity than the other portions of the plate segments 41. In detail, the weak portions are more readily deformed than the other portions of the plate segments 41 when any change occurs in the gap between the adjacent heat transfer pipes 20, for example, when the bending step reduces the distance between the heat transfer pipes 20 on the inner side of bending. Being more readily deformed than the other portions means being more readily bent than the other portions, in an exemplary case of the heat exchanger 1A.

In detail, the weak portions are made of fin-bent portions 42 formed by bending the plate segments 41 so as to protrude downward.

The fin-bent portions 42 are formed by bending, into a V-shape, the plate segments 41 at the center in the arrangement direction of the heat transfer pipes 20. That is, the fin-bent portions 42 are V-shaped bent portions of the plate segments 41 located at the center of the gap between the adjacent heat transfer pipes 20. These fin-bent portions 42, when the bending step of the fabrication process changes the distance between the adjacent heat transfer pipes 20, are more readily deformed or bent than the other portions of the plate segments 41. In response to a change in the distance between the heat transfer pipes 20, the fin-bent portions 42 are deformed such that the angle defined by the V-shape is increased or decreased. In other words, the fin-bent portions 42 extend or contract while maintaining the fold lines and cause the fin 40A to deform regularly, like bellows, in the bending step of the fabrication process. The fin-bent portions 42 can thus prevent the bending step from causing irregular deformation of the fin 40A and impairment of the ventilation performance. The fin-bent portions 42 can ensure the ventilation performance of the fin 40A at a sufficiently high level. In addition, the fin-bent portions 42, which extend or contract like bellows in response to a compressive force applied in a step of bending the headers 11 and 12, can prevent the compressive force from being concentrated at the heat transfer pipes 20. The fin-bent portions 42 can therefore avoid deformation of the heat transfer pipes 20.

Each of the fin-bent portions 42 defines a V-shape of which the tip is oriented downward. The fin-bent portion 42 having this shape guides water drops adhering on the fin 40A to the tip of the V-shape and facilitates drainage of the water drops. The fin-bent portion 42 can therefore improve the drainage performance of the fin 40A.

The fin-bent portions 42 are located at the end faces of the plate segments 41 that face the inner side of bending, so as to achieve deformation depending on a compressive force applied in the bending step of the fabrication process.

In detail, as illustrated in FIG. 4, the bent section 16 of the header 12 is bent toward the rear side B when viewed from the right. The rear side B thus corresponds to the inner side of bending of the bent section 16. The rear side B of the bent section 16 is likely to receive a large compressive force in the bending step of the fabrication process. The fin-bent portions 42 are thus provided to the portions encompassing the end faces of the plate segments 41 on the rear side B, that is, the end faces on the rear side B and the portions therearound. The end face means a side surface of the plate segment 41 of which the main surfaces are vertically directed.

Each of the fin-bent portions 42 defines an isosceles triangular shape having the base located adjacent to the end face of the plate segment 41 on the rear side B, when the plate segment 41 is viewed in the direction orthogonal to the main surfaces. The fin-bent portion 42 is formed by bending the plate segment 41 along the equal sides, serving as mountain fold lines 421 and 422, of the isosceles triangle, and along the perpendicular line, serving as a valley fold line 424, from a vertex 423 of the isosceles triangle to the base. The fin-bent portion 42 formed by bending the plate segment 41 thus has an area expanding toward the rear side B. The bending step of the fabrication process applies a compressive force increasing from the neutral plane toward rear side. The fin-bent portion 42 having an area expanding toward the rear side B can be deformed in accordance with a compressive force. This fin-bent portion 42 is more readily deformed than the heat transfer pipes 20 by a compressive force applied in the bending step, and can suppress the compressive force in the bending step from being applied to the heat transfer pipes 20.

The fin-bent portion 42, formed by bending the plate segment 41 in the above-described manner, has a V-shape becoming deeper toward the rear side B. The fin-bent portion 42 thus defines a V-shaped groove on the upper surface of the plate segment 41, of which the depth increases toward the rear side B, as illustrated in FIG. 3. The fin-bent portion 42 having this structure can facilitate effective drainage of water drops adhering on the fin 40A to the outside of the fin 40A.

The above-mentioned fold line 424 of the fin-bent portion 42, when being extended, preferably intersects the center C1 of bending, which is illustrated in FIG. 4. This fold line 424 can achieve uniform application of a compressive force to the individual sites of the fin-bent portion 42 in the bending step of the fabrication process, which is likely to result in regular deformation of the fin-bent portion 42. This structure can thus prevent the compressive force from being concentrated at some of the heat transfer pipes 20.

The vertex 423, corresponding to the intersection of the fold lines 421 and 422, is preferably located on or near the neutral plane of the plate segment 41. This structure can effectively place the fin-bent portion 42 to the site expected to receive a compressive force in the bending step of the fabrication process.

The following describes a method of fabricating the heat exchanger 1A including such fins 40A, with reference to FIGS. 5 to 7.

FIG. 5 is a flowchart illustrating the method of fabricating the heat exchanger 1A. FIG. 6 is a front view of multiple heat transfer pipes 20 that hold fins 30 and unprocessed fins 50 therebetween in a step of building a semifinished heat exchanger 2 involved in the method of fabricating the heat exchanger 1A. FIG. 7 is a front view of the semifinished heat exchanger 2 fabricated in the step of building the semifinished heat exchanger 2 involved in the method of fabricating the heat exchanger 1A.

As illustrated in FIG. 5, the method first involves preparing linear headers, heat transfer pipes 20, and fins 30 (Step S1). The linear headers mean headers having linearly extending pipe axes without the bent sections 15 and 16, before being bent into the headers 11 and 12. Two linear headers are prepared through press working of metal plates made of the above-mentioned material, for example.

The fins 30 having the above-described shape are prepared through press working of metal plates made of the above-mentioned material, for example. Also prepared are other fins, which have a larger length from the mountain portions 401 to the valley portions 402 of the corrugation than that of the fins 30, and from which the fins 40A are yielded. The other fins are hereinafter referred to as “unprocessed fins”.

The heat transfer pipes 20 having the above-described shape are also prepared through extrusion processing of a metal member made of the above-mentioned material.

The preparation step is followed by a step of building the semifinished heat exchanger 2 with the prepared linear headers, heat transfer pipes 20, fins 30, and unprocessed fins (Step S2).

This building step first involves arranging the heat transfer pipes 20 such that the pipe axes are oriented in the same direction and the flat surfaces face each other. Each adjacent two of the heat transfer pipes 20 hold the fin 30 or the unprocessed fin such that the mountain portions 401 and the valley portions 402 of the corrugation face the flat surfaces of the heat transfer pipes 20. As illustrated in FIG. 6, unprocessed fins 50 are held between the heat transfer pipes 20 coupled to a section P1 of linear headers 21 and 22, which corresponds to the bent sections 15 and 16 to be formed in Step S3 described below. In contrast, the fins 30 are held between the heat transfer pipes 20 coupled to the other sections P2 and P3 of the linear headers 21 and 22.

One and the other ends of the heat transfer pipes 20 holding the fins or unprocessed fins therebetween are inserted into the insertion holes, which are not illustrated, of the linear headers 21 and 22, thereby building a core. The individual parts of the built core are then brazed to each other, and thus produce the semifinished heat exchanger 2 illustrated in FIG. 7.

The building step is followed by a step of forming fin-bent portions 42, as illustrated in FIG. 5 (Step S3). In detail, each of the unprocessed fins 50 of the resulting semifinished heat exchanger 2 has multiple plate segments 41 disposed between the mountain portions 401 and the valley portions 402 of the corrugated shape, as in FIG. 3. These plate segments 41 extend across the gap between the heat transfer pipes 20. After producing the semifinished heat exchanger 2, the teeth of a comb-like tool, which is not illustrated, are introduced into the gap between the heat transfer pipes 20 from the rear side B. The teeth are urged onto the individual plate segments 41, and thus bend the plate segments 41 into the above-described V-shape. This step forms fin-bent portions 42 on the rear side of the plate segments 41. The fin-bent portions 42 each define a V-shaped groove shallower than that described above with reference to FIG. 3. The angle formed between the V-shaped groove is almost 180°. The above-described steps yield the fins 40A having the fin-bent portions 42.

The resulting semifinished heat exchanger 2 is then bent, as illustrated in FIG. 5 (Step S4).

This bending step involves urging a punch, which is not illustrated, onto the section P1 illustrated in FIG. 7, which corresponds to the above-described bent sections 15 and 16, from the rear side B adjacent to the fin-bent portions 42. This step thus bends the semifinished heat exchanger 2 into an L-shape.

The fin-bent portions 42, which are located on the inner side of bending, receive a compressive force. The compressive force further bends the fin-bent portions 42, and thus deepens the V-shaped grooves defined by the fin-bent portions 42 into a depth equal to the depth illustrated in FIG. 3. The V-shaped grooves defined by the fin-bent portions 42 form a narrowed angle therebetween, which is equal to the angle illustrated in FIG. 3. The fin-bent portions 42 can thus prevent the compressive force from being concentrated at the heat transfer pipes 20 in the bending step. This structure can avoid deformation of the heat transfer pipes 20, and thus avoid a decrease in the heat exchange efficiency of the heat exchanger 1A.

Such changes in the V-shaped grooves defined by the fin-bent portions 42 are mere regular deformation of the fins 40A. The fins 30 thus tend to have similar ventilation resistances, and are less likely to decrease the heat exchange efficiency of the heat exchanger 1A.

The bending of the semifinished heat exchanger 2 into an L-shape deepens the above-described V-shaped grooves defined by the fin-bent portions 42. The bending step also forms the L-shaped bent sections 15 and 16 in the linear headers. This step thus produces the heat exchanger 1A including the headers 11 and 12 having the bent sections 15 and 16. The above-described steps complete the heat exchanger 1A.

Step S2 is also called a step of building the semifinished heat exchanger 2 in the present disclosure. Step S4 is also called a step of producing the heat exchanger 1A or a bending step. The fin-bent portions 42, which are the portions of the plate segments 41 hung downward, are also called hung portions.

The linear header 21 and the linear header 22 prepared in Step S1 are examples of a first header having a first linear pipe section and a second header having a second linear pipe section in the present disclosure. The headers 11 and 12 are examples of the first header and the second header in the present disclosure. The bent sections 15 and 16 are examples of a first bent section and a second bent section in the present disclosure. The linear sections 17 and 18 are examples of the first linear section and the second linear section in the present disclosure. The fins 40A and the fins 30 are examples of first fins and second fins in the present disclosure. The heat transfer pipes 20 disposed adjacent to the bent sections 15 and 16 are examples of first heat transfer pipes in the present disclosure. The heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18 are examples of second heat transfer pipes in the present disclosure.

As described above, the heat exchanger 1A according to Embodiment 1 includes the heat transfer pipes 20 disposed adjacent to the bent sections 15 and 16, and the fins 40A fixed to the heat transfer pipes 20. These fins 40A have the fin-bent portions 42 serving as the weak portions. Since the fin-bent portions 42 have a lower rigidity than the other portions, and are more readily deformed than the other portions in response to a change in the distance between the adjacent heat transfer pipes, the fin-bent portions 42 of the fins 40A located between the heat transfer pipes 20 are deformed earlier than the other portions when the bending step of the process of fabricating the heat exchanger 1A changes the distance between the heat transfer pipes 20. These features can suppress a compressive force from being concentrated at the heat transfer pipes 20, and avoid deformation of the heat transfer pipes 20. The avoidance of deformation of the heat transfer pipes 20 leads to avoidance of a decrease in the heat exchange efficiency of the heat exchanger 1A.

The fin-bent portions 42 are located at the end faces of the plate segments 41 of the fins 40A that face the inner side of bending, and thus readily receive a compressive force in the bending step. That is, the compressive force, applied to the heat transfer pipes 20 in the bending step, is likely to be concentrated at the fin-bent portions 42 and less likely to be concentrated at the heat transfer pipes 20. The heat exchanger 1A can avoid deformation of the heat transfer pipes 20, just by providing the fin-bent portions 42 at the end faces of the plate segments 41 that face the inner side of bending. The heat exchanger 1A capable of avoiding deformation of the heat transfer pipes 20 can thus be readily fabricated.

The fin-bent portions 42 are each bent such that the plate segment 41 of the fin 40A protrudes from one of the main surfaces. The fin-bent portion 42 can adjust the amount of protrusion depending on a compressive force applied in the bending step, and thus prevent the compressive force from being concentrated at the heat transfer pipes 20.

The fin-bent portions 42 are each formed by bending the plate segment 41 of the fin 40A into a V-shape of which the tip is oriented downward. The fin-bent portion 42 can thus guide water drops adhering on the plate segment 41 to the tip of the V-shape, and facilitate highly efficient drainage of the water drops.

The fin-bent portions 42 can maintain the bent V-shapes of the plate segments 41, regardless of a compressive force applied in the bending step. The fins 40A are thus less likely to suffer from increased ventilation resistances, in comparison to the fins 30 irregularly deformed by a compressive force applied in the bending step. These fins 40A can maintain the ventilation resistance within a certain low range, and thus avoid a decrease in the heat exchange efficiency of the heat exchanger 1A.

The bending step may warp the heat transfer pipes 20. The heat transfer pipes 20 may be warped provided that the heat transfer pipes 20 are not buckled. FIG. 8 illustrates such warped heat transfer pipes 20.

FIG. 8 is an enlarged rear view illustrating a part of a modification of the heat exchanger 1A according to Embodiment 1, which includes warped heat transfer pipes 20 of the heat exchanger 1A. FIG. 8 illustrates the linear sections 17 and 18 of the headers 11 and 12 of the heat exchanger 1A after the bending step when viewed from the inner side of bending.

As illustrated in FIG. 8, the heat transfer pipes 20 coupled to the linear sections 17 and 18 of the headers 11 and 12 may be warped so as to be in a shape of the convex curves oriented toward the −X side, that is, toward the bent sections 15 and 16. The heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18 are warped because of being drawn and deformed toward the bent sections 15 and 16, when the bending step changes the distance between the heat transfer pipes 20 disposed adjacent to the bent sections 15 and 16.

This phenomenon of warpage of the heat transfer pipes 20 occurs in a uniform bending process, which involves applying a load at the center of a linear-pipe header and thus bending the linear-pipe header while holding the lateral parts on both sides of the center in the longitudinal direction. This uniform bending process may warp the heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18 on both sides of the bent sections 15 and 16. These heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18 on both sides may be warped.

In the case of a rotary draw bending process, while no warpage occurs in some heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18 located in the direction of rotation of a clamp used in this process, some warpage occurs in other heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18 located in the direction opposite to the direction of rotation of the clamp. The heat transfer pipes 20 located at such positions may be warped. The rotary draw bending process involves holding parts of the linear headers 21 and 22 between the clamp and a columnar bending die, shifting the clamp in the circumferential direction of the bending die and thus rotating the clamp about the central axis of the bending die, and thereby yielding bent sections 15 and 16.

In the case of a bending process, while warpage occurs in some heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18 located on one side of the bent sections 15 and 16, no warpage occurs in other heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18 located on the other side of the bent sections 15 and 16. The heat transfer pipes 20 may be deformed into such shapes.

This phenomenon of warpage of the heat transfer pipes 20 occurs not only in the linear sections 17 and 18 but also in the bent sections 15 and 16. The warpage of the heat transfer pipes 20 disposed adjacent to the bent sections 15 and 16 is not as large as the warpage of the heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18. That is, the warpage of the heat transfer pipes 20 disposed adjacent to the bent sections 15 and 16 may be smaller than the warpage of the heat transfer pipes 20 disposed adjacent to the linear sections 17 and 18.

Embodiment 2

In Embodiment 1, the weak portions of the plate segments 41 of the fins 40A are made of the fin-bent portions 42. These weak portions, however, are mere examples. The weak portions are only required to have a lower rigidity than the other portions of the plate segments 41, and be more readily deformed than the other portions in response to a change in the distance between the adjacent heat transfer pipes 20.

In a heat exchanger 1B according to Embodiment 2, each of the weak portions of the plate segments 41 is made of a portion encompassing a notch cut out from the end face of the plate segment 41 toward the central part. The following describes a structure of the heat exchanger 1B with reference to FIG. 9. The description of Embodiment 2 is mainly directed to the differences from Embodiment 1.

FIG. 9 is an enlarged perspective view illustrating a part of heat transfer pipes 20 and a fin 40B included in the heat exchanger 1B according to Embodiment 2. FIG. 9 illustrates the heat transfer pipes 20 coupled to the bent sections 15 and 16 of the headers 11 and 12, and the fin 40B fixed to the heat transfer pipes 20, as in FIG. 3. FIG. 9 illustrates the fin 40B having substantially no deformation, in order to facilitate an understanding, although the fin 40B is expected to be deformed by a compressive force applied in the bending step.

In the heat exchanger 1B, the weak portions are made of portions encompassing notches 43 illustrated in FIG. 9 cut out from the end faces of the plate segments 41. That is, the weak portions are made of the notches 43 and the portions of the plate segments 41 around the notches 43.

The notches 43 are each cut out from the end face of the plate segment 41 on the rear side B toward the central part of the plate segment 41. The notch 43 extends through the plate segment 41. The notch 43 has a shape of wedge of which the tip is oriented toward the central part of the plate segment 41. That is, the notch 43 has a triangular shape of which the vertex is located adjacent to the central part of the plate segment 41 and the opposite side of the vertex is located at the end face of the plate segment 41, when viewed in the direction orthogonal to the main surfaces of the plate segment 41.

In detail, the notches 43 each have a shape of isosceles triangle of which the base is oriented toward the inner side of bending of the bent sections 15 and 16 illustrated in FIG. 1, that is, toward the rear side B, when the plate segment 41 is viewed in the direction orthogonal to the main surfaces. The compressive force applied in the bending step increases from the neutral plane toward rear side B. The notches 43 having such a shape allow the fin 40B to be deformed in accordance with a compressive force. The notches 43 can thus achieve deformation by a compressive force applied in the bending step, and suppress the compressive force from being applied to the heat transfer pipes 20.

Even if the notches 43 having the above-described shape are deformed by a compressive force, the end faces of the notches 43 of the plate segments 41 are less likely to overlap with each other or protrude outward. These notches 43 are less likely to suffer from increased ventilation resistances.

The notches 43 cut the plate segments 41 into the above-described shape. That is, the notches 43 extend completely through the plate segments 41 in the thickness direction. The notches 43 can thus facilitate the fin 40B to be deformed by a compressive force applied in the bending step.

This specification defines the notch as a cut-out hole ranging from the end face toward the central part of the plate segment 41. The notches 43 are thus also called cut-out holes.

The method of fabricating the heat exchanger 1B is identical to the method of fabricating the heat exchanger 1A according to Embodiment 1, except for that: (1) the fins 40B are prepared in Step S1 described above in Embodiment 1, as in the preparation of the fins 30; (2) The notches 43 are formed through press working, for example, simultaneously with the formation of the fins 40B; and (3) Step S3 described above in Embodiment 1 is accordingly skipped. The fabrication method is thus not redundantly described. The notches 43 each have a triangular shape, which is formed by punching a hole in the plate segment 41 through press working.

The above-described notches 43 are examples of first notches in the present disclosure. The end faces of the plate segments 41 on the rear side B provided with the notches 43 are examples of one of an end face of the plate segment 41 that faces the inner side of bending of the first bent section or an end face that faces the outer side of bending of the first bent section in the present disclosure. The fins 40B are examples of first fins in the present disclosure. The shape of the notches 43 may also be called a V-shape.

As described above, in the heat exchanger 1B according to Embodiment 2, the plate segments 41 of the fins 40B have the notches 43, and the portions of the plate segments 41 encompassing the notches 43 serve as the weak portions. The portions of the plate segments 41 encompassing the notches 43 are thus deformed earlier than the other portions of the plate segments 41, when the bending step of the fabrication process applies a compressive force to the heat transfer pipes 20. These features of the heat exchanger 1B can prevent the compressive force from being concentrated at the heat transfer pipes 20. The heat exchanger 1B can also avoid deformation of the heat transfer pipes 20.

The method of fabricating the heat exchanger 1B can achieve formation of the notches 43 through press working, for example, simultaneously with the formation of the fins 40B. The heat exchanger 1B can therefore be fabricated by the same number of steps as those of a normal heat exchanger including fins without the notches 43.

Modifications

Although the heat exchanger 1B according to Embodiment 2 has the triangular notches 43, these notches 43 are mere examples. The notches 43 are only required to be designed such that the portions of the plate segments 41 encompassing the notches 43 have a lower rigidity than the other portions of the plate segments 41 and are more readily deformed than the other portions of the plate segments 41 in response to a change in the gap between the adjacent heat transfer pipes 20. The notches 43 may have any shape provided that these requirements are satisfied.

FIG. 10 is an enlarged perspective view illustrating a part of a modification of the heat exchanger 1B according to Embodiment 2. FIG. 11 is an enlarged perspective view illustrating a part of another modification of the heat exchanger 1B according to Embodiment 2. FIGS. 10 and 11 each illustrate the area of the heat exchanger 1B identical to the area illustrated in FIG. 9.

As illustrated in FIG. 10, the notches 43 may have a rectangular shape. In detail, the notches 43 may have a rectangular shape, which is cut out from the end face of the plate segment 41 on the rear side B toward the front side F and of which the longitudinal direction is oriented toward the front. In other words, the notches 43 may have an I-shape having the longitudinal direction oriented toward the front.

These notches 43 preferably have a width in the transverse direction smaller than that of the base of the isosceles triangle defined by each of the notches 43 described above in Embodiment 2. This structure can achieve a smaller cut-out area of the plate segment 41 than that in Embodiment 2, and make the heat exchange performance of the fins 40B as high as possible.

As illustrated in FIG. 11, the notches 43 may also have a semicircular shape. In detail, the notches 43 may have a semicircular shape, of which the center is located adjacent to the end face of the plate segment 41 and the convex arc is oriented toward the central part of the plate segment 41. This structure can suppress stresses from being concentrated at the inner angles of the notches 43 in the bending step, and prevent the fins 40B from being broken or deformed into an unintended shape. The arc of a semicircle may be an arc of a true circle or an arc of an ellipse.

The mode illustrated in FIG. 11 may also be applied to Embodiment 2 or the mode illustrated in FIG. 10, although this modification is not illustrated. That is, the inner angles of the triangular or rectangular notches 43 may be rounded into a semicircular shape. In this case, the arc of the semicircle preferably has a shape depending on the inner angle.

Embodiment 2 and the modes illustrated in FIGS. 10 and 11 may also be applied to Embodiment 1. That is, the fin-bent portions 42 may be provided with the notches 43.

Embodiment 3

In Embodiment 1, the weak portions of the plate segments 41 of the fins 40A are made of the fin-bent portions 42. In Embodiment 2, the weak portions are made of the portions of the plate segments 41 encompassing the notches 43. These weak portions, however, are mere examples. As described above in Embodiment 2, the weak portions are only required to have a lower rigidity than the other portions of the plate segments 41, and be more readily deformed than the other portions in response to a change in the distance between the adjacent heat transfer pipes 20.

In a heat exchanger 1C according to Embodiment 3, the plate segments 41 each have a weak portion made of a thin portion. The following describes a structure of the heat exchanger 1C with reference to FIG. 12. The description of Embodiment 3 is mainly directed to the differences from Embodiments 1 and 2.

FIG. 12 is an enlarged perspective view illustrating a part of heat transfer pipes 20 and a fin 40C included in the heat exchanger 1C according to Embodiment 3. FIG. 12 illustrates the heat transfer pipes 20 coupled to the bent sections 15 and 16 of the headers 11 and 12, and the fin 40C fixed to the heat transfer pipes 20, as in FIG. 3. FIG. 12 illustrates the fin 40C having substantially no deformation, in order to facilitate an understanding as in FIG. 9, although the fin 40C is expected to be deformed by a compressive force applied in the bending step.

As illustrated in FIG. 12, the weak portions in the heat exchanger 1C are made of thin portions 44 having a smaller thickness than the other portions of the plate segments 41.

The thin portions 44 have a triangular shape, of which the vertex is located adjacent to the central part of the plate segment 41 and the opposite side of the vertex is located at the end face of the plate segment 41, when viewed in the direction orthogonal to the main surfaces of the plate segment 41. That is, the thin portions 44 have the same flat shape as the notches 43 described above with reference to FIG. 9. The thin portions 44 thus each have the same contour as that of the notches 43 illustrated in FIG. 9 when the plate segment 41 is viewed in the direction orthogonal to the main surfaces of the plate segment 41. The following description thus excludes a specific description of the contour of the thin portion 44. The thin portions 44 having such a shape are deformed by a compressive force applied in the bending step, and can suppress the compressive force from being applied to the heat transfer pipes 20.

The thin portions 44 have a smaller thickness than the other portions of the plate segments 41, as described above. This thickness of the thin portions 44 is constant. The thin portions 44 receive heat from the heat transfer pipes 20 and thus contribute to heat exchange, unlike the notches 43 described above in Embodiment 2. The fins 40C can therefore achieve higher heat exchange efficiency than the fins 40B described above in Embodiment 2.

The thin portions 44 may each be embossed on one of the main surfaces of the plate segment 41, although this modification is not illustrated in FIG. 12. In this case, the embossment of the thin portions 44 is preferably oriented toward the gravity direction, that is, the downward direction. Although the thin portions 44 symmetric about the X axis are adjacent to each other in the vertical direction in FIG. 12, the thin portions 44 having the identical shape may be adjacent to each other in the vertical direction.

The method of fabricating the heat exchanger 1C is identical to the method of fabricating the heat exchanger 1A according to Embodiment 1, except for that: (1) the fins 40C are prepared in Step S1 described above in Embodiment 1, as in the preparation of the fins 30, and the thin portions 44 are formed through press working, for example, simultaneously with the formation of the fins 40C; and (2) Step S3 described above in Embodiment 1 is accordingly skipped. The fabrication method is thus not redundantly described.

The above-described thin portions 44 are examples of first thin portions in the present disclosure. The end faces of the plate segments 41 on the rear side B provided with the thin portions 44 are examples of one of an end face of the plate segment 41 that faces the inner side of bending of the first bent section, or an end face that faces the outer side of bending of the first bent section in the present disclosure. The fins 40C are examples of first fins in the present disclosure.

As described above, in the heat exchanger 1C according to Embodiment 3, the fins 40C have the thin portions 44 serving as the weak portions. The thin portions 44 are thus deformed earlier than the other portions of the plate segments 41, when the bending step of the fabrication process applies a compressive force to the heat transfer pipes 20. These features can prevent the compressive force from being concentrated at the heat transfer pipes 20. The heat exchanger 1C can also avoid deformation of the heat transfer pipes 20.

The method of fabricating the heat exchanger 1C can achieve formation of the thin portions 44 through press working, for example, simultaneously with the formation of the fins 40C, as in Embodiment 2. The heat exchanger 1C can therefore be fabricated by the same number of steps as those of a normal heat exchanger including fins without the thin portions 44.

Modification

Although the heat exchanger 1C according to Embodiment 3 has the thin portions 44 having a triangular shape in a plan view, these thin portions 44 are mere examples. The thin portions 44 may have any shape provided that the requirements for weak portions are satisfied, for the same reason as that described above in Embodiment 2.

FIG. 13 is an enlarged perspective view illustrating a part of a modification of the heat exchanger 1C according to Embodiment 3. FIG. 13 illustrates the area of the heat exchanger 1C identical to the area illustrated in FIG. 12.

As illustrated in FIG. 13, the thin portions 44 may have a semicircular shape. In detail, the thin portions 44 may have a semicircular shape, of which the center is located adjacent to the end face of the plate segment 41 and the convex arc is oriented toward the central part of the plate segment 41, as in the mode illustrated in FIG. 11. This structure can suppress stresses from being concentrated in the bending step, as in the mode illustrated in FIG. 11. The arc of a semicircle in this structure may be an arc of an ellipse.

The thin portions 44 in Embodiment 3 may also be applied to the fin-bent portions 42 of the fins 40A described above in Embodiment 1. For example, the fin-bent portions 42, each having a shape of isosceles triangle of which the base is located adjacent to the end face of the plate segment 41 on the rear side B when the plate segment 41 is viewed in the direction orthogonal to the main surfaces, may be formed as the thin portions 44 having a smaller thickness than that of the other portions of the plate segments 41. The thin portions 44 can be more readily bent, and thus facilitate deformation of the fin-bent portions 42.

Embodiment 4

In Embodiment 2, the notches 43 are located at the end faces of the plate segments 41 that face the inner side of bending. This structure including the notches 43 is a mere example. Notches may also be provided to the other portions of the plate segments 41.

In a heat exchanger 1D according to Embodiment 4, each of the plate segments 41 has notches 45 and 46. The following describes a structure of the heat exchanger 1D with reference to FIG. 14. The description of Embodiment 4 is mainly directed to the differences from Embodiments 1 to 3.

FIG. 14 is an enlarged sectional view illustrating a part of a fin 40D included in the heat exchanger 1D according to Embodiment 4. The fin 40D illustrated in FIG. 14 is one of the fins to be coupled to the bent sections 15 and 16 of the headers 11 and 12 included in the heat exchanger 1D. FIG. 14 illustrates the fin 40D before being deformed in accordance with the bending of the headers 11 and 12, in order to facilitate an understanding.

As illustrated in FIG. 14, in the heat exchanger 1D, each of the plate segments 41 of the fin 40D has the notch 45 corresponding to the notch 43 in Embodiment 2, and the notch 46 disposed at a position different from the notch 45. These notches 45 and 46 both correspond to the weak portions described above in Embodiments 1 to 3.

The notches 45 are disposed at the end faces of the plate segments 41 that face the rear side B, as in Embodiment 2. The notches 45 have a rectangular shape, which is cut out from the end face of the plate segment 41 on the rear side B toward the front side F and of which the longitudinal direction is oriented toward the front, like the notches 43 according to the modification of Embodiment 2. The bottoms of the notches 45 adjacent to the front side F are rounded into a semicircular shape. The notches 45 are disposed at the end faces of the plate segments 41 that face the rear side B and have the above-described shape. The notches 45 can thus facilitate the plate segments 41 to be deformed by a compressive force applied in the bending step, and suppress the compressive force from being applied to the heat transfer pipes 20, as in Embodiment 2.

In contrast, the notches 46 are disposed at the end faces of the plate segments 41 that face the front side F. That is, the notches 46 are disposed at the end faces opposite to the end faces of the plate segments 41 provided with the notches 45. The notches 46 each have a shape defined by inverting the notch 45 into the frontward direction. In other words, the notch 46 is symmetric to the notch 45 about the line L1 representing the neutral plane.

The heat exchanger 1D is fabricated through Steps S1, S2, and S4 except for Step S3 described above in Embodiment 2. The fabrication method in Embodiment 2 requires alignment of the end faces of the fins 40B provided with the notches 43 to one side before holding the fins 40B between the heat transfer pipes 20 in Step S2. In contrast, the method of fabricating the heat exchanger 1D according to Embodiment 4 does not require alignment of the end faces of the fins 40D provided with the notches 45 to one side in Step S2, because the opposite end surfaces of each plate segment 41 both have the notches 45 and 46. That is, the end faces provided with the notches 45 and the end faces provided with the notches 46 may exist on the same side. The method of fabricating the heat exchanger 1D can thus achieve improved efficiency.

When the semifinished heat exchanger 2 is bent in Step S4 of the method of fabricating the heat exchanger 1D, while the end faces of the plate segments 41 that face the inner side of bending receive a compressive force, the end faces of the plate segments 41 on the outer side of bending receive a tensile force. In the heat exchanger 1D, while the end faces of the plate segments 41 that face the inner side of bending have the notches 45, the end faces of the plate segments 41 on the outer side of bending have the notches 46. When the semifinished heat exchanger 2 is bent in Step S4, the plate segments 41 are deformed such that the notches 45 are compressed and the notches 46 are stretched. The method of fabricating the heat exchanger 1D is thus less likely to apply a compressive force and a tensile force to the heat transfer pipes 20. These features can avoid deformation of the heat transfer pipes 20, and avoid a decrease in the heat exchange efficiency of the heat exchanger 1D.

The above-described notches 45 and 46 are examples of first notches and second notches in the present disclosure. The end faces of the plate segments 41 that face the rear side B and are provided with the notches 45 are examples of one of an end face of the plate segment 41 that faces the inner side of bending of the first bent section, or an end face that faces the outer side of bending of the first bent section in the present disclosure. The end faces of the plate segments 41 that face the front side F and are provided with the notches 46 are examples of the other of the end face of the plate segment 41 that faces the inner side of bending of the first bent section, or the end face that faces the outer side of bending of the first bent section in the present disclosure.

As described above, in the heat exchanger 1D according to Embodiment 4, each of the plate segments 41 of the fins 40D has the notch 45 and the notch 46 having a shape and a position symmetric to the notch 45. Such fins 40D may be inversed in the step of building the heat exchanger 1D with the fins 40D. The method of fabricating the heat exchanger 1D can thus exclude the alignment of the fins 40D to one side, and can therefore achieve improved efficiency of the building step.

The heat exchanger 1D can also avoid deformation of the heat transfer pipes 20, as in Embodiment 2.

Modifications

In Embodiment 4, the notches 45 and 46 have a rectangular shape. The notches 45 and 46, however, may have another shape. The notches 45 and 46 may have any shape provided that the requirements for weak portions are satisfied for the same reason as that described above in Embodiment 2. The shapes of the notches 45 and 46 are only required to be symmetric about the neutral plane. For example, the notches 45 and 46 may have a triangular shape or semicircular shape described above in Embodiment 2 and the modification of Embodiment 2.

Although Embodiment 4 is applied to the case of the weak portions made of the notches 45 and 46, Embodiment 4 can also be applied to the case of the weak portions made of the thin portions 44. In detail, the notches 45 may be replaced with the thin portions 44, and the notches 46 may be replaced with thin portions 44 symmetric to the original thin portions 44 about the neutral plane. The thin portions 44 symmetric about the neutral plane in this case are examples of second thin portions in the present disclosure.

Embodiment 4 may also be applied to the case of the weak portions made of the fin-bent portions 42. In detail, the notches 45 may be replaced with the fin-bent portions 42, and the notches 46 may be replaced with fin-bent portions 42 symmetric to the original fin-bent portions 42 about the neutral plane.

Embodiment 5

In Embodiment 1, the weak portions of the plate segments 41 of the fins 40A are made of the fin-bent portions 42. In Embodiment 2, the weak portions are made of the portions of the plate segments 41 encompassing the notches 43. In Embodiment 3, the weak portions are made of the thin portions 44. These weak portions, however, are mere examples. The weak portions are only required to have a lower rigidity than the other portions of the plate segments 41, and be more readily deformed than the other portions in response to a change in the distance between the adjacent heat transfer pipes 20, as described above.

In a heat exchanger 1E according to Embodiment 5, each of the plate segments 41 has a weak portion made of a warped portion 47. The following describes a structure of the heat exchanger 1E with reference to FIG. 15. The description of Embodiment 5 is mainly directed to the differences from Embodiments 1 to 4.

FIG. 15 is an enlarged perspective view illustrating a part of heat transfer pipes 20 and a fin 40E included in the heat exchanger 1E according to Embodiment 5. FIG. 15 illustrates the heat transfer pipes 20 coupled to the bent sections 15 and 16 of the headers 11 and 12, and the fin 40E fixed to the heat transfer pipes 20, as in FIG. 3. FIG. 15 illustrates the fin 40E having no deformation in the bending step, in order to facilitate an understanding as in FIGS. 9 and 12, although the fin 40E is expected to be deformed by a compressive force applied in the bending step.

As illustrated in FIG. 15, the weak portions in the heat exchanger 1E are made of the warped portions 47 having a larger amount of warpage than the other portions of the plate segments 41.

The mountain portions 401 and the valley portions 402 of the corrugated shape defined by each fin 40E are brazed to the heat transfer pipes 20. Each of the mountain portions 401 and the valley portions 402 has two warped portions 47 on both sides of the site to be brazed of the mountain portion 401 or the valley portion 402. The warped portions 47 located at these positions make the widths W1 and W2 of the mountain portions 401 and the valley portions 402 of the corrugated shape, larger than the half of the wavelength L2 of the corrugated shape. Although FIG. 15 illustrates the warped portions 47 on the rear side B, the warped portions 47 extend from the rear side B to the front side F, which is not illustrated. The warped portions 47 having this shape and positions are deformed by a compressive force and a tensile force applied in the bending step, and can prevent the fins 40E themselves from being broken. The warped portions 47 can also suppress a compressive force and a tensile force from being applied to the heat transfer pipes 20.

The method of fabricating the heat exchanger 1E is identical to the method of fabricating the heat exchanger 1A according to Embodiment 1, except for that: (1) the fins 40E having the warped portions 47 are prepared in Step S1 described above in Embodiment 1; and (2) Step S3 described above in Embodiment 1 is accordingly skipped. The fabrication method is thus not redundantly described.

As described above, in the heat exchanger 1E according to Embodiment 5, the fins 40E have the warped portions 47 serving as the weak portions. The warped portions 47 are deformed earlier than the other portions of the plate segments 41, when the bending step of the fabrication process applies a compressive force or a tensile force to the heat transfer pipes 20. These features can prevent the compressive force or tensile force from being concentrated at the heat transfer pipes 20. The features can thus avoid deformation of the heat transfer pipes 20.

In particular, a plate segment 41 may be broken by being stretched by a tensile force exceeding the tolerance. The warped portions 47 of the heat exchanger 1E have larger rooms to be stretched and can thus prevent the fins 40E themselves from being broken.

The above-described heat exchangers 1A to 1E and the methods of fabricating the heat exchangers 1A to 1E according to the embodiments of the present disclosure are mere examples.

In Embodiments 1 to 5, the fins 40A to 40E having the weak portions are fixed to each of the heat transfer pipes 20 coupled to the bent sections 15 and 16 of the headers 11 and 12. In other words, the fins 40A to 40E are fixed to all of the heat transfer pipes 20 disposed adjacent to the bent sections 15 and 16. These heat exchangers 1A to 1E, however, are mere examples. In the heat exchangers 1A to 1E, the weak portions are only required to be provided to at least one of the fins fixed to the heat transfer pipes 20 coupled to the bent sections 15 and 16. In short, the fins 40A to 40E correspond to at least one of the fins.

FIG. 16 is a development view of a modification of the heat exchanger 1A according to Embodiment 1. FIG. 17 is a development view of another modification of the heat exchanger 1A according to Embodiment 1. FIGS. 16 and 17 each illustrate the heat exchanger 1A in which the bent sections 15 and 16 of the modification or the other modification of the heat exchanger 1A are developed into a linear shape. The section corresponding to the bent sections 15 and 16 developed into a linear shape is provided with a reference symbol P4.

As illustrated in FIG. 16, in the section P4 corresponding to the bent sections 15 and 16 of the headers 11 and 12, the fins 40A having weak portions and the fins 30 having no weak portions are alternately arranged in the arrangement direction of the heat transfer pipes 20. That is, the fins 30, which are less likely to be deformed than the fins 40A in the bending step and can thus readily maintain the ventilation performance, are disposed adjacent to the bent sections 15 and 16, and can therefore improve the ventilation performance of the heat exchanger 1A.

Alternatively, as illustrated in FIG. 17, in the section P4 corresponding to the bent sections 15 and 16 of the headers 11 and 12, the fins 30 having no weak portions may constitute fin arrays successively aligned in the arrangement direction of the heat transfer pipes 20. The fins 40A may each be disposed between adjacent two of the fin arrays. The fins 30 are less likely to be deformed than the fins 40A in the bending step and can thus readily maintain the ventilation performance, as described above. This modification can therefore achieve higher ventilation performance of the heat exchanger 1A than that in Embodiment 1.

That is, the bent sections 15 and 16 are only required to be provided with at least one of the fins 40A to 40E. The heat exchangers 1A to 1E satisfying this requirement can avoid deformation of the heat transfer pipes 20 and avoid a decrease in the heat exchange efficiency.

In Embodiments 1 to 4, the weak portions are provided to the end faces of the plate segments 41 of the fins 40A that face the inner side of bending. These positions of the weak portions, however, are mere examples. The weak portions are each only required to be provided to at least one of the end face of the plate segment 41 that faces the inner side of bending of the bent section 15, or the end face that faces the outer side of bending of the bent section 15. The weak portions disposed at these positions are deformed with higher priority, when the bending step of the process of fabricating the heat exchangers 1A to 1D changes the distance between the heat transfer pipes 20, for example, when the bending step narrows or widens the distance between the heat transfer pipes 20. The weak portions can thus prevent a compressive force or a tensile force from being concentrated at the heat transfer pipes 20.

In Embodiments 1 to 5, the fins 40A to 40E do not protrude further than the heat transfer pipes 20 toward the rear side B, or further than the heat transfer pipes 20 toward the front side F. These shapes of the fins 40A to 40E, however, are mere examples. The fins 40A to 40E may protrude further than the heat transfer pipes 20 toward the rear side B. Alternatively, the fins 40A to 40E may protrude further than the heat transfer pipes 20 toward the front side F.

FIG. 18 is a sectional view of the fins 40A included in still another modification of the heat exchanger 1A according to Embodiment 1. FIG. 18 illustrates sections of the heat transfer pipes 20 and the modified fins 40A vertically overlapping with the bent sections 15 and 16. FIG. 18 illustrates the components without hatching, in order to facilitate an understanding.

As illustrated in FIG. 18, the fins 40A may protrude further toward the front side F, than the distal ends of the flat-shaped sections of the heat transfer pipes 20 on the front side F. That is, the fins 40A may protrude toward the outer side of bending of the bent sections 15 and 16. The front side F of the fins 40A illustrated in FIG. 18 corresponds to the outer side of bending, into which the ambient air is introduced during a heating operation of the outdoor unit. The parts of the fins 40A adjacent to the front side F are readily subject to frost adhering thereon. The fins 40A, which protrude further than the heat transfer pipes 20 toward the front side F, can expand the area of the parts readily subject to frost, and thus avoid a decrease in the heat exchange performance. The fins 40A having such a shape can expand the heat transfer area, and thus improve the heat exchange performance.

As illustrated in FIG. 18, the fins 40A may protrude further toward the rear side B, than the proximal ends of the flat-shaped sections of the heat transfer pipes 20 on the rear side B. That is, the fins 40A may protrude toward the inner side of bending of the bent sections 15 and 16. The fins 40A protrude by a distance D1, which may be equal to the distance D2 of protrusion of the fins 40A toward the front side F, or shorter than the distance D2, for example. The fins 40A having such a shape can expand the area of the parts readily subject to frost, and avoid a decrease in the heat exchange performance. The fins 40A can also expand the heat transfer area, and improve the heat exchange performance.

Although the fins 40A protrude toward both of the inner and outer sides of bending of the bent sections 15 and 16 in the mode illustrated in FIG. 18, the fins 40A may protrude toward at least one of the inner and outer sides of bending of the bent sections 15 and 16.

Although the fins 30 and 40A to 40E have a corrugated shape in Embodiments 1 to 5, these fins 30 and 40A to 40E are mere examples. The fins 30 and 40A to 40E are only required to be disposed between the adjacent heat transfer pipes 20 and transfer heat from the heat transfer pipes 20.

Although the heat transfer pipes 20 are flat pipes in Embodiments 1 to 5, these heat transfer pipes 20 are mere examples. The heat transfer pipes 20 are only required to at least connect the bent sections 15 and 16 to each other. The heat transfer pipes 20 may also be circular pipes, for example.

Although the heat exchangers 1A to 1E are each installed in the outdoor unit of the air-conditioning apparatus in the examples described above in Embodiments 1 to 5, these heat exchangers 1A to 1E are mere examples. The heat exchangers 1A to 1E may also be applied to general apparatuses and machines that require heat exchange. For example, the heat exchanger 1A may also be installed in an indoor unit of an air-conditioning apparatus.

The above descriptions of Embodiments 1 to 5 refer to the directions of the heat exchangers 1A to 1E, such as vertical direction and horizontal direction, which are provided for descriptive purposes as a matter of convenience. These directions may be varied provided that the components of the heat exchangers 1A to 1E have the same positional relationship.

The foregoing describes some example embodiments for explanatory purposes. Although the foregoing discussion has presented specific embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of the invention is defined only by the included claims, along with the full range of equivalents to which such claims are entitled.

This application claims the benefit of Japanese Patent Application No. 2022-42358, filed on Mar. 17, 2022, the entire disclosure of which is incorporated by reference herein.

Reference Signs List

- 1A, 1B, 1C, 1D, 1E Heat exchanger
- 2 Semifinished heat exchanger
- 11, 12 Header
- 13, 14 Joint section
- 15, 16 Bent section
- 17, 18 Linear section
- 20 Heat transfer pipe
- 21, 22 Linear header
- 30 Fin
- 40A, 40B, 40C, 40D, 40E Fin
- 41 Plate segment
- 42 fin-bent portion
- 43 Notch
- 44 Thin portion
- 45, 46 Notch
- 47 Warped portion
- 50 Unprocessed fin
- 401 Mountain portion
- 402 Valley portion
- 421, 422, 424 Fold line
- 423 Vertex
- A1, A2 Pipe axis
- B Rear side
- C1 Center
- D1, D2 Distance
- F Front side
- L1 Line
- L2 Wavelength
- P1, P2, P3, P4 Section
- W1, W2 Width

HEAT EXCHANGER, AND METHOD FOR MANUFACTURING HEAT EXCHANGER

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CPC

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