JP7788862B2 - Method for manufacturing a heat exchanger and method for manufacturing an air conditioner - Google Patents

Description

The present disclosure relates to a method for manufacturing a heat exchanger and a method for manufacturing an air conditioner.

When a heat exchanger is used as an evaporator, the air around the fins condenses, which can result in condensed water adhering to the fin surface. Some heat exchangers are designed to discharge condensed water along the fin surface to prevent the condensed water from freezing and increasing the airflow resistance of the fins due to the condensed water adhering to the fins.

For example, Patent Document 1 discloses a heat exchanger equipped with fins formed in a corrugated shape with multiple waves made up of a series of peaks and valleys, with the peaks and valleys of the waves oriented in a direction that is inclined relative to the vertical direction. The heat exchanger described in Patent Document 1 discharges condensed water by causing the adhering condensed water droplets to flow along the inclined peaks and valleys.

Japanese Patent Application Laid-Open No. 2008-116095

In the heat exchanger described in Patent Document 1, the tube axes of the heat transfer tubes are oriented in a vertical direction. Meanwhile, the corrugated peaks and valleys of the fins are oriented in a direction that is inclined relative to the vertical direction. As a result, the corrugated peaks and valleys of the fins are inclined relative to the side surfaces of the heat transfer tubes. Therefore, when attempting to press the fins against the heat transfer tubes for brazing, the corrugated peaks and valleys of the fins may be inclined more than necessary relative to the side surfaces of the heat transfer tubes, resulting in insufficient joint strength. Furthermore, the fins may fall over from the side surfaces of the heat transfer tubes. As such, the heat exchanger described in Patent Document 1 is not easy to manufacture.

The present disclosure has been made to solve the above-mentioned problems, and aims to provide a method for manufacturing a heat exchanger and an air conditioner that are easy to manufacture and can discharge condensed water.

To achieve the above object, a method for manufacturing a heat exchanger according to the present disclosure includes a step of sandwiching a plate-like body between a pair of rollers having intermeshing corrugated blades and rotating the pair of rollers to form fins by bending the plate-like body into a corrugated shape having peaks and valleys, with multiple waves arranged in one direction in the order of peaks, first connecting portions connecting the peaks and valleys, and valleys . In the fin-forming step, one axial end of the pair of rollers processes one end of the plate-like body into a shape in which the peaks of the peaks are positioned in one direction relative to the first connecting portions .

According to the configuration of the present disclosure, the end portions of the fins in the manufactured heat exchanger , along the direction in which the peaks of the peaks and the bottoms of the valleys extend, are located in one direction relative to the first connecting portion, so that when condensed water adhering to the fins reaches the end portions along the direction in which the peaks of the peaks and the bottoms of the valleys extend, the condensed water can be collected at the peaks and discharged. Furthermore, manufacturing is easy because it is only necessary to mold the end portions along the direction in which the peaks of the peaks and the bottoms of the valleys extend into the above-mentioned shape.

FIG. 1 is a perspective view of a heat exchanger according to a first embodiment of the present disclosure; FIG. 1 is a front view of a heat exchanger according to a first embodiment of the present disclosure; 1 is a cross-sectional view of a fin included in a heat exchanger according to a first embodiment of the present disclosure; FIG. 1 is an enlarged perspective view of a portion of a heat transfer tube included in a heat exchanger according to a first embodiment of the present disclosure and a portion of a fin attached to the portion of the heat transfer tube; 4A is a cross-sectional view taken along the VA-VA cutting line shown in FIG. 4; FIG. 4B is a cross-sectional view taken along the VB-VB cutting line shown in FIG. 4; and FIG. 4C is a cross-sectional view taken along the VC-VC cutting line shown in FIG. 4. FIG. 1 is a cross-sectional view of a front end portion of a fin and a heat transfer tube included in a heat exchanger according to a first embodiment of the present disclosure. Flowchart of a method for manufacturing a heat exchanger according to a first embodiment of the present disclosure FIG. 1 is a perspective view of a fin forming device used in a fin forming step included in a method for manufacturing a heat exchanger according to a first embodiment of the present disclosure. FIG. 1A is an enlarged perspective view showing the shape of a blade at one end in the axial direction of a roller included in a fin forming device used in a fin forming step of a method for manufacturing a heat exchanger according to a first embodiment of the present disclosure; FIG. 1B is an enlarged perspective view showing the shape of a blade at the center of the roller in the axial direction; FIG. 10 is a front view of a stack of heat transfer tubes and semi-finished fins that are to be assembled to a header in a core assembly step included in the method for manufacturing a heat exchanger according to the first embodiment of the present disclosure. Front view of fins collapsed onto heat transfer tubes FIG. 10 is an enlarged perspective view of a portion of a heat exchanger according to a second embodiment of the present disclosure. 10 is a rear view of a fin included in a heat exchanger according to a second embodiment of the present disclosure. FIG. 10 is a front view of a fin included in a heat exchanger according to a second embodiment of the present disclosure. FIG. 10 is an enlarged perspective view showing the shape of a blade at one axial end of a roller included in a fin forming device used in a method for manufacturing a heat exchanger according to a second embodiment of the present disclosure. (A) A conceptual diagram of a modified example of a fin forming device used in a method for manufacturing a heat exchanger according to a second embodiment of the present disclosure; (B) A cross-sectional view of a fin formed by a fin forming roller provided in the modified example of the fin forming device; (C) A cross-sectional view of a fin processed by a pitch-narrowing roller provided in the modified example of the fin forming device; and (D) A cross-sectional view of a fin processed by a pitch-widening roller provided in the modified example of the fin forming device. Block diagram of an air conditioner according to a third embodiment of the present disclosure. 10 is a cross-sectional view of a modified example of a fin included in the heat exchanger according to the first embodiment of the present disclosure. FIG. 10 is a cross-sectional view of another modified example of the fins included in the heat exchanger according to the first embodiment of the present disclosure. FIG. 10 is a cross-sectional view of yet another modified example of the fins included in the heat exchanger according to the first embodiment of the present disclosure. FIG. 10 is a perspective view of a modified example of the heat exchanger according to the first embodiment of the present disclosure. FIG. 10 is a perspective view of another modified example of the heat exchanger according to the first embodiment of the present disclosure.

Hereinafter, a method for manufacturing a heat exchanger and a method for manufacturing an air conditioner according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In the drawings, identical or equivalent parts are designated by the same reference numerals. In the illustrated Cartesian coordinate system XYZ, the direction in which the axes of the heat transfer tubes of the heat exchanger extend is the vertical direction, and the direction in which the heat transfer tubes are arranged is the horizontal direction. The vertical direction is the Z-axis, the horizontal direction is the X-axis, and the direction perpendicular to the Z-axis and X-axis is the Y-axis. This coordinate system will be referenced as appropriate in the following description.

(Embodiment 1)
The heat exchanger according to the first embodiment has corrugated fins, each of which has a series of waves with adjacent peaks and valleys. In this heat exchanger, the peaks and valleys of the corrugated fins are oriented diagonally downward to facilitate the discharge of condensed water. First, the overall configuration of the heat exchanger will be described with reference to Figures 1 to 3.

Figure 1 is a perspective view of a heat exchanger 1A according to embodiment 1. Figure 2 is a front view of the heat exchanger 1A. Figure 3 is a cross-sectional view of the fins 30A included in the heat exchanger 1A. Note that the fins 30A are omitted from Figure 1 for ease of understanding. Also, in Figure 2, the shape of the fins 30A as viewed from the front is simplified to a zigzag shape in which a straight line bends left and right multiple times. Furthermore, Figure 3 shows a cross-sectional view of the fins 30A taken in the front-to-rear direction, i.e., at the center in the Y direction.

As shown in Figures 1 and 2, the heat exchanger 1A includes headers 11 and 12 that are connected to external equipment and through which a refrigerant is supplied and discharged, multiple heat transfer tubes 20 that are connected to the headers 11 and 12 and through which the refrigerant flows, and fins 30A attached to the heat transfer tubes 20.

As shown in Figure 1, the headers 11 and 12 are cylindrical. Although not shown, the headers 11 and 12 are provided with connecting pipes for connection to external equipment that supplies and discharges the refrigerant. Furthermore, flow paths for distributing and concentrating the refrigerant are formed inside the headers 11 and 12. As shown in Figure 1, the headers 11 and 12 are arranged spaced apart from each other in the vertical direction, with their cylindrical axes oriented left and right. A plurality of heat transfer pipes 20 are connected to the headers 11 and 12 to circulate the refrigerant between them.

Each heat transfer tube 20 is formed in a tubular shape to allow the refrigerant to flow, with its tube axis oriented vertically. The upper and lower ends of the heat transfer tubes 20 are inserted into insertion holes (not shown) in the cylindrical walls of the headers 11 and 12. As a result, when refrigerant flows through the headers 11 and 12, the refrigerant circulates inside the heat transfer tubes 20.

In order to facilitate the transfer of heat from the refrigerant flowing through the heat transfer tubes 20, each heat transfer tube 20 is made of a metal with high thermal conductivity, such as pure aluminum or an aluminum alloy. Furthermore, the heat transfer tubes 20 are formed in the shape of a flat tube with a flat pipe cross section. Since the heat exchanger 1A is designed to exchange heat with air blown in the front-to-rear direction during use, the heat transfer tubes 20 have their short axis of the flat pipe cross section oriented in the left-to-right direction and their long axis oriented in the front-to-rear direction to reduce ventilation resistance. The heat transfer tubes 20 are arranged in the left-to-right direction at regular intervals. Fins 30A are sandwiched between the heat transfer tubes 20, as shown in Figure 2.

The fins 30A have a corrugated cross-sectional shape formed by bending a plate-like body to increase the contact area with the air and improve heat exchange performance. Specifically, the fins 30A are formed from a metal plate with high thermal conductivity, for example, a metal plate made of the same material as the heat transfer tubes 20. The fins 30A are formed by bending the metal plate into a corrugated cross-sectional shape with multiple waves of peaks 31 and valleys 33 (see FIG. 3) adjacent to one another in one direction, i.e., the +Z direction. In the fins 30A, the peaks 32 of the peaks 31 are angular, inverted U-shaped, and the bottoms 34 of the valleys 33 are angular, inverted U-shaped. The peaks 31 and valleys 33 are connected by linear connecting portions 35 in cross-sectional view. The fins 30A are brazed to the heat transfer tubes 20 with the peaks 32 and bottoms 34 abutting the heat transfer tubes 20, as shown in FIG. 2.

In recent years, fins 30A with such a corrugated shape have tended to be made with a smaller pitch P between the peaks 31 or valleys 33 in order to improve the heat exchange performance of the heat exchanger 1A. However, when the pitch P is reduced, the angle θ at which the fins 30A rise, as shown in Figure 3, may become larger. In other words, when waves rise from the corrugated bottom 34, the angle θ at which the waves rise may become larger. For example, the angle θ may become close to perpendicular, or more specifically, an angle between 85° and 90°.

When the fins 30A have such a near-vertical rise angle, if the fins 30A are used with the direction in which the peaks 31 or valleys 33 are aligned vertically, i.e., in the Z direction, condensed water may adhere to the surface of the fins 30A, making it difficult to drain. When the fins 30A are used in this orientation, the plate surfaces of the connection portions 35 of the fins 30A become nearly horizontal, causing condensed water droplets to remain on the plate surfaces of the connection portions 35. In this case, the condensed water remaining on the plate surfaces of the connection portions 35 may block the spaces between the peaks 31 or valleys 33 of the fins 30A. This may increase the ventilation resistance of the fins 30A. In particular, if the condensed water freezes, the ventilation resistance increases, reducing the heat exchange performance of the heat exchanger 1A.

In order to prevent a decline in heat exchange performance, the corrugated peaks 31 and valleys 33 of the fins 30A are oriented diagonally downward at the downwind end of the fins 30A, where condensation tends to accumulate. Next, the detailed configuration of the fins 30A will be described with reference to Figures 4-6.

Figure 4 is an enlarged perspective view of a portion of a heat transfer tube 20 provided in heat exchanger 1A and a portion of a fin 30A attached to that portion of the heat transfer tube 20. Figure 5(A) is a cross-sectional view taken along the VA-VA cutting line shown in Figure 4. Figure 5(B) is a cross-sectional view taken along the VB-VB cutting line shown in Figure 4. Figure 5(C) is a cross-sectional view taken along the VC-VC cutting line shown in Figure 4. Figure 6 is a cross-sectional view of the front end of the fin 30A and the heat transfer tube 20.

Note that in Figure 4, the rising angle of the fins 30A is shown more gently than the actual angle to make it easier to understand. Also, in Figure 6, the internal space of the heat transfer tube 20 is omitted.

Although not shown, a fan is installed on the rear side of the heat exchanger 1A, and heat is exchanged between the air blown by the fan and the internal refrigerant. Therefore, as shown in FIG. 4, wind W is blown onto the fins 30A from the rear side, i.e., the -Y side. As shown in FIGS. 5(A) and 5(B), the peaks 31 and valleys 33 at the rear end and the center in the front-to-rear direction of the fins 30A, i.e., the windward end and the center in the airflow direction of the fins 30A, are oriented in the -X and +X directions. In contrast, as shown in FIG. 5(C), at the front end of the fins 30A, i.e., the downwind end of the fins 30A, the peaks 31 and valleys 33 are oriented in the -X and -Z directions, and the +X and -Z directions. In other words, the peaks 31 and valleys 33 are oriented in the lower left and lower right directions.

Explaining in more detail, in the entire fin 30A, as shown in Fig. 6, the peak portion 31 has a shape in which an upper plate-like portion 311 facing upward and a lower plate-like portion 312 facing downward are connected at a peak 32. Also, the valley portion 33 has a shape in which an upper plate-like portion 331 facing upward and a lower plate-like portion 332 facing downward are connected at a bottom 34. The upper plate-like portion 311 of the peak portion 31 and the lower plate-like portion 332 of the valley portion 33 are connected by a connecting portion 36. Also, the lower plate-like portion 312 of the peak portion 31 is connected to the upper plate-like portion 331 of the adjacent valley portion 33 below by a connecting portion 35 .

The entire fin 30A has this shape, but at the downwind end of the fin 30A, the upper plate portion 311 and lower plate portion 312 of the peak portion 31 each extend diagonally downward to the left in a curved manner, more specifically, in an arc-like shape. The spacing between the upper plate portion 311 and lower plate portion 312 is constant. Furthermore, the upper plate portion 331 and lower plate portion 332 of the valley portion 33 each extend diagonally downward to the right in a curved manner, more specifically, in an arc-like shape. The spacing between the upper plate portion 331 and lower plate portion 332 is also constant. The peak portion 31 and valley portion 33 form a so-called banana shape. Because the fin 30A has this shape, the peak 32 and bottom 34 of the fin 30A are located below the connecting portions 35 and 36.

Here, the phrase "the top 32 or the bottom 34 is located below the connection portion 35" means that a portion of the top 32 or the bottom 34 is located below the connection portion 35. Specifically, this means that the end of the top 32 on the upper plate portion 311 side, more specifically, the end of the outer wall surface of the top 32 facing the outside of the corrugation, which is located on the upper plate portion 311 side, is located below the top surface of the connection portion 35. Furthermore, this means that the end of the bottom 34 on the lower plate portion 332 side, more specifically, the end of the inner wall surface of the bottom 34 facing the inside of the corrugation, which is located on the lower plate portion 332 side, is located below the top surface of the connection portion 35.
Furthermore, the expression "the top 32 or the bottom 34 is located below the connecting portion 36" means that a portion of the top 32 or the bottom 34 is located below the connecting portion 36, and more specifically, the end of the top 32 on the lower plate portion 312 side, more specifically, the end of the inner wall surface of the top 32 facing the inside of the corrugation, which is located on the lower plate portion 312 side, is located below the upper surface of the connecting portion 36. Furthermore, the expression "the end of the bottom 34 on the upper plate portion 331 side, more specifically, the end of the outer wall surface of the bottom 34 facing the outside of the corrugation, which is located on the upper plate portion 331 side" means that the end of the bottom 34 on the upper plate portion 331 side, more specifically, the end of the outer wall surface of the bottom 34 facing the outside of the corrugation, which is located below the upper surface of the connecting portion 36.

When condensed water adheres to the fins 30A, it tends to collect on the downwind side due to the wind from a fan (not shown). However, as described above, the peaks 32 and bottoms 34 at the downwind end of the fins 30A are located below the connecting portions 35 and 36. As a result, if condensed water collects on the downwind end of the fins 30A, it flows along the connecting portions 35 and 36, the peaks 31, and the valleys 33 of the fins 30A, and into the peaks 32 and bottoms 34. Meanwhile, as shown in FIG. 4, the downwind end of the fins 30A, i.e., the +Y end, protrudes further toward the +Y side than the heat transfer tubes 20. Therefore, condensed water that flows into the peaks 32 and bottoms 34 flows directly in the -Z direction, i.e., downward, without reaching the heat transfer tubes 20, i.e., without blocking the airflow path. These factors allow condensed water to be easily discharged from the fins 30A in the heat exchanger 1A. As a result, the decrease in heat exchange efficiency of heat exchanger 1A caused by condensed water can be suppressed.

The solid line L in Figure 6 indicates the plate surface at the center of the fin 30A in the fore-and-aft direction, as shown in Figure 5(B). As is clear from the position of this solid line L, the plate surface of the peaks 31 and valleys 33 becomes lower from the center of the fin 30A in the fore-and-aft direction toward the front end, i.e., the downwind end. As a result, condensed water can easily flow in.

Next, a manufacturing method for heat exchanger 1A will be described with reference to Figures 7-10.

Figure 7 is a flowchart of the manufacturing method for heat exchanger 1A. Figure 8 is a perspective view of fin forming device 40 used in the fin forming step included in the manufacturing method for heat exchanger 1A. Figure 9(A) is an enlarged perspective view showing the shape of blades 410, 420 at one end in the axial direction A of rollers 41, 42 of fin forming device 40. Figure 9(B) is an enlarged perspective view showing the shape of blades 410, 420 at the center in the axial direction A of rollers 41, 42. Figure 10 is a front view of stacked body 50 made of stacked heat transfer tubes 20 and semi-finished fins 150, which will be assembled to headers 11, 12 in the core assembly step included in the manufacturing method for heat exchanger 1A.

First, although not shown, the headers 11, 12 and heat transfer tubes 20 of the material, shape, and number described above are prepared. In parallel with the preparation of the heat transfer tubes 20, the fin forming process shown in Figure 7 is carried out to prepare the fins 30A of the material, shape, and number described above (step S1).

The fin forming process uses a fin forming device 40 shown in Figure 8. This fin forming device 40 uses a pair of rollers 41, 42 having multiple corrugated teeth, i.e., multiple blades 410, 420, on their outer surfaces. The blades 410, 420 are meshed with each other. As shown in Figures 9(A) and 9(B), the blades 410, 420 are trapezoidal in cross section. As shown in Figure 9(A), at one end of the rollers 41, 42 in the axial direction A, specifically the +A end, the height H1 of the trapezoid in cross section is greater than the height H2 of the trapezoid in cross section of the blades 410, 420 at the center of the axial direction A, as shown in Figure 9(B). In other words, at the +A end of the rollers 41, 42, the distance from the top to the bottom of the blades 410, 420 is greater, while the distance between the blades 410, 420 is smaller at the center of the axial direction A.

In the fin forming process, a strip-shaped metal sheet 100, such as an aluminum sheet, which is the material for the fin 30A, is inserted between a pair of rollers 41, 42 of the fin forming device 40, and the rollers 41, 42 are rotated in opposite rotation directions R. As a result, the metal sheet 100 is formed into a corrugated shape in which the distance from crest to bottom is large at the +A end of the axial direction A of the rollers 41, 42, and the distance from crest to bottom is small in other parts of the rollers 41, 42. As a result, a corrugated fin is produced in which the distance from crest to bottom of the waves is large only at one end and smaller in other parts. Hereinafter, this fin will be referred to as a semi-finished fin.

Once the semi-finished fins are produced in the fin forming process, the core assembly process shown in Figure 7 is carried out using those semi-finished fins (step S2).

In the core assembly process, the prepared heat transfer tubes 20 are arranged with their tube axes parallel to one another and their flat surfaces facing each other. Furthermore, as shown in FIG. 10 , semi-finished fins 150 are sandwiched between the heat transfer tubes 20 with the corrugated waves oriented in the axial direction of the heat transfer tubes 20 and with the peaks 31 and valleys 33 of the corrugations facing the flat surfaces of the heat transfer tubes 20. This results in an assembly of a stack 50 in which the heat transfer tubes 20 and semi-finished fins 150 are alternately stacked. The assembled stack 50 is then compressed in the stacking direction. That is, pressure is applied from the directions indicated by arrows A1 and A2 to compress the heat transfer tubes 20 so that the gaps between them narrow. At this time, by applying a stronger compressive force to the side in the tube axis direction D1 than to the opposite side, the distance from the top to the bottom of the corrugations at one end is reduced to the same distance as the top to the bottom of the corrugations at the other end, causing the plate surface forming the corrugations at one end from the top to the bottom to be curved upward in a convex shape. This forms the fin 30A shaped as described using Figures 4-6.

Next, one end and the other end of the heat transfer tubes 20 of the laminate 50, compressed in the directions indicated by arrows A1 and A2, are inserted into the insertion holes 13 and 14 of the prepared headers 11 and 12, and the laminate 50 is assembled to the headers 11 and 12. This completes the core assembly process. Then, although not shown, the compressive force applied to the laminate 50 is adjusted, and in this state, a restraining jig is attached to the laminate 50 to maintain the compressed state of the laminate 50. This completes the core assembly process.

Following the core assembly process, the brazing process shown in Figure 7 is carried out (step S3). Although not shown in detail, the heat transfer tubes 20 and fins 30A, and the heat transfer tubes 20 and headers 11 and 12 of the stack 50 with the restraining jig attached are brazed together. After brazing, the restraining jig is removed from the stack 50. This completes the production of the heat exchanger 1A.

For example, the headers 11, 12, heat transfer tubes 20, and fins 30A described above are formed from bracing sheets whose surfaces are covered with brazing material, and the headers 11, 12, heat transfer tubes 20, and fins 30A are then used to assemble the core described above. Flux is then applied to the assembled core. For example, a non-corrosive flux is applied. The core with the applied flux is then heated to melt the flux and remove the oxide film on the core surface. The core is then further heated to melt the brazing material, which penetrates into the gaps between each part, and then allowed to cool. This completes the brazing of the core. As a result, the heat exchanger 1A is produced and completed.

As described above, in the manufacturing method for heat exchanger 1A, the laminate 50 is compressed in the core assembly process (step S2). In the heat exchanger described in Patent Document 1, the peaks and valleys of the corrugations of the corrugated fins are inclined in the same direction, so even a small compressive force can cause the fins to collapse onto the heat transfer tubes.

Figure 11 is a front view of a fin 130 that has fallen onto a heat transfer tube 120. As shown in Figure 11, for example, in the case of the heat exchanger configuration described in Patent Document 1, the peaks and valleys of the corrugations of the corrugated fin 130 may fall in the axial direction of the heat transfer tube 120. In this case, the peaks and bottoms of the corrugations of the fin 130 cannot form a sufficient contact area with the heat transfer tube 120, and a sufficiently large brazed joint cannot be formed. As a result, sufficient joint strength cannot be obtained.

In contrast, in the heat exchanger 1A, as shown in FIG. 6, the corrugated shape of the fins 30A has a wave-like shape that curves upward convexly only at the downwind end in cross section. As a result, the peaks 31 and valleys 33 of the fins 30A are less likely to collapse when compressed during the core assembly process (step S2) shown in FIG. 7. Furthermore, the peaks 32 and bottoms 34 contact the heat transfer tubes 20 over a sufficient contact area, allowing for the formation of a sufficiently large brazed joint. As a result, the fins 30A and the heat transfer tubes 20 can be joined with sufficient strength. Furthermore, the heat exchanger 1A is easily manufactured because only the downwind end of the fins 30A needs to be shaped so that the peaks 31 and valleys 33 face downward.

Note that the term "downward" or "downward direction" in embodiment 1 is an example of a direction as defined in the present disclosure. Furthermore, the upper plate portion 311 and the lower plate portion 312 of the peak portion 31 are an example of a first plate portion and a second plate portion as defined in the present disclosure. Furthermore, the upper plate portion 331 and the lower plate portion 332 of the valley portion 33 are an example of a third plate portion and a fourth plate portion as defined in the present disclosure. Furthermore, the connecting portions 35 and 36 are an example of a first connecting portion and a second connecting portion as defined in the present disclosure. Furthermore, the core assembly process is an example of a process of attaching fins 30A to a plurality of heat transfer tubes 20 as defined in the present disclosure.

As described above, in the heat exchanger 1A according to embodiment 1, at the ends of the corrugated fins 30A in the direction in which the peaks 32 of the corrugated peaks 31 and the bottoms 34 of the corrugated valleys 33 extend, both the peaks 32 of the peaks 31 and the bottoms 34 of the valleys 33 are located below the connecting portions 35, 36 connecting the peaks 31 and the valleys 33. Therefore, even if condensed water adheres to the fins 30A at the ends of the fins 30A in the direction in which the peaks 32 of the peaks 31 and the bottoms 34 of the valleys 33 extend, the condensed water can be collected at the peaks 32 and the bottoms 34. Furthermore, because the condensed water collects at the ends of the fins 30A, it falls from the ends and can be easily discharged from the fins 30A.

Furthermore, the end of the fin 30A described above, in the direction in which the peaks 32 of the peak portions 31 and the bottoms 34 of the valley portions 33 extend, is located on the downwind side of the fin 30A. Condensed water blown by the wind tends to accumulate on the downwind side of the fin 30A. Because both the peaks 32 and bottoms 34 at the end where condensed water tends to accumulate are located below the connecting portions 35 and 36, condensed water tends to collect more easily at the peaks 32 and bottoms 34, resulting in high drainage efficiency.

In the heat exchanger 1A, condensed water can be easily drained simply by molding the downwind end of the fin 30A into a shape in which the top 32 and bottom 34 are in the positions described above. In this way, a heat exchanger 1A that easily drains condensed water can be easily manufactured.

Furthermore, in the heat exchanger 1A, the tops 32 and bottoms 34 are located below the connection portions 35 and 36 only at the downwind ends of the fins 30A, so the tops 32 and bottoms 34 can be in contact with the heat transfer tubes 20 over a sufficient area in areas other than the downwind ends of the fins 30A. As a result, the fins 30A and the heat transfer tubes 20 can be joined with sufficient strength.

(Modification)
In the first embodiment, the left side of the corrugated fin 30A waving in the left-right direction, i.e., the −X side, is defined as peak portion 31, and its −X end is defined as peak 32. The right side of the fin 30A, i.e., the +X side, is defined as valley portion 33, and its +X end is defined as bottom 34. However, this is for convenience of explanation, and peak portion 31 and valley portion 33 may be interchanged.

Furthermore, while the corrugations of the fins 30A undulate in the left-right direction, the direction in which the corrugations of the fins 30A undulate may be changed as long as the relative positional relationships of the components of the heat exchanger 1A are maintained. For example, when air is blown from the left-right direction, the corrugations of the fins 30A may undulate in the front-to-back direction.

(Embodiment 2)
In the first embodiment, the heat transfer tubes 20 are arranged in a single row. As a result of the single row of the heat transfer tubes 20, there is one set of headers 11, 12. However, in the heat exchanger 1A, the number of rows of the heat transfer tubes 20 and the number of sets of the headers 11, 12 are not limited. The number of rows of the heat transfer tubes 20 and the number of sets of the headers 11, 12 may be at least one.

The heat exchanger 1B according to the second embodiment includes heat transfer tubes 21, 22 arranged in two rows. The configuration of the heat exchanger 1B will be described below with reference to Figures 12-15. The second embodiment will be described mainly with respect to the configuration that differs from the first embodiment.

Figure 12 is an enlarged perspective view of a portion of a heat exchanger 1B according to embodiment 2. Figure 13 is a rear view of a fin 30B provided in the heat exchanger 1B. Figure 14 is a front view of the fin 30B. Figure 15 is an enlarged perspective view showing the shape of blades 410, 420 at one end in the axial direction A of rollers 41, 42 provided in a fin forming device 40 used in the manufacturing method of the heat exchanger 1B.

For ease of understanding, Figure 12 shows only two sets of heat transfer tubes 21 and 22 and the fins 30B sandwiched between the heat transfer tubes 21 and 22, out of the multiple heat transfer tubes 21 and 22 and multiple fins 30B provided in the heat exchanger 1B.

As shown in Figure 12, the heat exchanger 1B includes a plurality of heat transfer tubes 21 arranged on the front side, a plurality of heat transfer tubes 22 arranged on the rear side, and fins 30B extending in the front-to-rear direction and passing between the heat transfer tubes 21 and between the heat transfer tubes 22.

Heat transfer tubes 21 and 22 are each formed from the same material and with the same size and shape as heat transfer tube 20 described in embodiment 1. Like heat transfer tube 20, they are arranged in the left-right direction with their flat surfaces facing each other. Although not shown, headers 11 and 12 are arranged above and below each row of heat transfer tubes 21 and 22, respectively, and are connected to heat transfer tubes 21 and 22. Refrigerant can be supplied to heat transfer tubes 21 and 22 from headers 11 and 12, or refrigerant can be discharged from heat transfer tubes 21 and 22 to headers 11 and 12.

In contrast, fin 30B, like fin 30A described in embodiment 1, is formed in a corrugated shape that undulates vertically. Unlike fin 30A, the top 32 and bottom 34 of the corrugated shape of fin 30B are curved in cross section, specifically parabolic in cross section. Fin 30B is also longer in the front-to-rear direction than fin 30A and is sandwiched between both the heat transfer tubes 21 arranged on the front side and the heat transfer tubes 22 arranged on the rear side. Furthermore, multiple raised portions 37 are formed on the surface of fin 30B to facilitate airflow. Furthermore, through holes 38 are formed in three locations to facilitate condensed water discharge: (1) the center between the heat transfer tubes 21 in the left-to-right direction; (2) the center between the rows of heat transfer tubes 21 and 22 in the front-to-rear direction and the center of fin 30B in the left-to-right direction; and (3) the center between the heat transfer tubes 22 in the left-to-right direction.

Like the heat exchanger 1A of embodiment 1, the heat exchanger 1B is used in an environment where air is blown from the rear side. Therefore, to efficiently discharge condensed water that tends to collect on the downwind side, the fins 30B have corrugated peaks 31 and valleys 33 oriented left and right at the rear end (i.e., the upwind end) shown in FIG. 13 , whereas the peaks 31 and valleys 33 at the front end (i.e., the downwind end) shown in FIG. 14 are curved downward toward their tips. Furthermore, the peaks 31 and valleys 33 are tapered toward their tips. As a result, the peaks 32 and bottoms 34 of the fins 30B are positioned lower than the connecting portions 35 connecting the peaks 31 and valleys 33 at the downwind end. As a result, the fins 30B can collect and discharge condensed water at the peaks 32 and bottoms 34.

The manufacturing method of the heat exchanger 1B is the same as that of the first embodiment, except that: (1) in the fin-forming process, one end of the rollers 41, 42 in the axial direction A, i.e., the +A end shown in FIG. 8, is formed into a trapezoidal cross-section as shown in FIG. 15, and blades 410, 420, the legs of which are curved in a convex arc shape opposite the direction of rotation R, are used to form curved peaks 31 and valleys 33 at the downwind ends of the fins 30B; (2) in the core-assembly process, the heat transfer tubes 21, 22 are arranged in two rows, the fins 30B are sandwiched between the two rows of heat transfer tubes 21, 22, and headers 11, 12 are attached to each row of the heat transfer tubes 21, 22; and (3) when compressing the sandwiched fins 30B in the core-assembly process, the process of bending the plate surfaces of the downwind ends of the fins 30B convexly upward, as described in the first embodiment, is not performed. Therefore, a detailed description of the manufacturing method will be omitted.

As described above, in the heat exchanger 1B according to embodiment 2, the heat transfer tubes 21, 22 are arranged in multiple rows, and the fins 30B are sandwiched between the heat transfer tubes 21, 22 in each row. At one end of the fins 30B in the direction in which the rows are arranged, the corrugated peaks 31 and valleys 33 face diagonally downward. Therefore, when the fins 30B are positioned with one end facing downwind, condensed water that collects downwind can flow to the peaks 32 of the peaks 31 and the bottoms 34 of the valleys 33 and be discharged outside the fins 30B.

Fin 30B also has a through hole 38 in the center in the front-to-back direction between the rows of heat transfer tubes 21 and 22, making it easy to drain condensed water. Fin 30B also has a through hole 38 in the center in the left-to-right direction between the heat transfer tubes 21 or between the heat transfer tubes 22, making it easy to drain condensed water.

(Modification)
The cut-and-raised portions 37 and the through-holes 38 described in the second embodiment are optional and may be omitted. The cut-and-raised portions 37 may be cut-outs. Naturally, the cut-and-raised portions 37, the through-holes 38, and the cut-outs may be formed in the fins 30A of the heat exchanger 1A according to the first embodiment.

Furthermore, in embodiment 2, the fin molding process included in the manufacturing method of heat exchanger 1B uses blades 410, 420 formed into a trapezoidal cross section as shown in Figure 15, with the legs of the trapezoidal cross section curved in a convex arc shape facing away from the direction of rotation R. This fin molding process alone causes the peak portions 31 and valley portions 33 shown in Figure 14 to curve downward as they approach the tips. However, the shape of fin 30B can also be modified by curving the plate surface of fin 30B when fin 30B is compressed in the core assembly process described in embodiment 1.

The cross-sectional shape of the blades 410, 420 may also be changed to the cross-sectional shape of a different desired fin 30B. For example, one end of the blades 410, 420 in the axial direction A of the rollers 41, 42 may be shaped so that one end of the fin 30B is processed into a shape such that the top 32 and bottom 34 are positioned below the connecting portions 35, 36, as described in embodiment 1. As a result, one end of the molded fin 30B may be shaped so that the top 32 and bottom 34 are positioned below the connecting portions 35, 36, as in embodiment 1. Alternatively, the one end of the blades 410, 420 may be shaped so that one end of the fin 30B is processed into a shape such that only one of the top 32 and bottom 34 is positioned below the connecting portion 35.

Furthermore, semi-finished fins 151 may be formed using rollers 41, 42 equipped with blades 410, 420 having the same cross-sectional shape as the final desired fin 30B but with a different pitch, and the corrugation pitch of the formed semi-finished fin 151 may be enlarged or reduced to produce fins 30B of the desired shape. This manufacturing method makes it easier to produce fins 30B with complex shapes.

Next, with reference to Figures 16(A)-16(D), we will explain the manufacturing method for the fin 30B using a modified fin forming device 40.

Figure 16 (A) is a conceptual diagram of a modified fin forming apparatus 40 used in the heat exchanger manufacturing method according to embodiment 2. Figure 16 (B) is a cross-sectional view of a fin formed by a fin forming roller provided in the modified fin forming apparatus 40. Figure 16 (C) is a cross-sectional view of a fin processed by a pitch-narrowing roller provided in the modified fin forming apparatus 40. Figure 16 (D) is a cross-sectional view of a fin processed by a pitch-widening roller provided in the modified fin forming apparatus 40.

As shown in Figures 16(A) to 16(D), a modified example of the fin forming device 40 includes: (1) fin forming rollers 43, 44 provided with blades having a fin cross-sectional shape with a corrugation pitch larger than that of the final desired fin 30B, which form a semi-finished fin 151; (2) pitch-reducing rollers 45, 46 which rotate at a slower speed than the fin forming rollers 43, 44 and thereby reduce the corrugation pitch of the semi-finished fin 151 formed by the fin forming rollers 43, 44; and (3) a pitch-widening roller 47 whose roller axis is oriented in the direction in which the semi-finished fin 152 with reduced corrugation pitch advances, and which comes into contact with the semi-finished fin 152 to widen the corrugation pitch and form a semi-finished fin 153 with a widened corrugation pitch. Fin 30B may also be produced by supplying a strip-shaped metal plate 100 to a modified version of this fin forming device 40, passing the metal plate 100 between fin forming rollers 43, 44, pitch-reducing rollers 45, 46, in that order, and then contacting the pitch-widening roller 47.

The corrugation pitch of the semi-finished fin 151 may be adjusted by incorporating a leaf spring into a modified fin forming device 40 instead of the pitch-reducing rollers 45, 46 and the pitch-widening roller 47. Alternatively, the corrugation pitch of the semi-finished fin 151 may be adjusted by incorporating a leaf spring into a modified fin forming device 40 in addition to the pitch-reducing rollers 45, 46 and the pitch-widening roller 47. The rotational speeds of the pitch-reducing rollers 45, 46 and the pitch-widening roller 47 may be adjusted to adjust the advancing speed of the semi-finished fins 151, 152 and thereby adjust the corrugation pitch of the semi-finished fins 152, 153 to be formed.

Of course, a modified version of the fin forming device 40 may include only the fin forming rollers 43 and 44. This is because the fin 30B can also be manufactured using such a device.

(Embodiment 3)
The heat exchangers 1A and 1B according to the first and second embodiments may be used in an air conditioner. The third embodiment is an air conditioner including the heat exchanger 1A according to the first embodiment.

The air conditioner according to embodiment 3 will be described below with reference to Figure 17. The description of embodiment 3 will focus on the configuration that differs from embodiments 1 and 2.

Figure 17 is a block diagram of an air conditioner 2 according to embodiment 3.

As shown in Figure 17, the air conditioner 2 includes a compressor 3, a fan 4, and a heat exchanger 1A. The compressor 3, fan 4, and heat exchanger 1A are incorporated into the outdoor unit housing 7, along with components such as an accumulator 5 and a four-way valve 6.

The compressor 3 is connected to the heat exchanger 1A, the accumulator 5, and the four-way valve 6, forming a refrigerant circuit that circulates the refrigerant.

On the other hand, fan 4 blows air to heat exchanger 1A. It is positioned on the rear side of heat exchanger 1A in the first embodiment. As a result, fan 4 blows air in a direction from the rear to the front of heat exchanger 1A. Heat exchanger 1A then exchanges heat between the refrigerant in the refrigerant circuit and the blown air. As a result, the air conditioner 2 performs air conditioning.

In this type of air conditioning, condensed water can adhere to the fins 30A of the heat exchanger 1A, increasing ventilation resistance and reducing the heat exchange performance of the heat exchanger 1A. However, as explained in embodiment 1, the heat exchanger 1A discharges condensed water with high efficiency from the downwind end of the fins 30A. As a result, the heat exchange performance of the heat exchanger 1A in the air conditioner 2 is less likely to deteriorate. This means that the air conditioning performance, i.e., heating and cooling performance, is also less likely to deteriorate.

The air conditioner 2 is manufactured by preparing various components such as the heat exchanger 1A, compressor 3, fan 4, accumulator 5, and four-way valve 6, forming a refrigerant circuit, and assembling them into the outdoor unit housing 7.

In manufacturing the air conditioner 2, it is desirable to position the fan 4 on the rear side of the fin 30A, as referred to in embodiment 1. Specifically, it is desirable to position the heat exchanger 1A and fan 4 so that the rear end of the fin 30A faces the blades of the fan 4, allowing the fan 4 to blow air from the rear of the fin 30A to the front. At the front end of the fin 30A, the corrugated peaks 31 and valleys 33 of the fin 30A face diagonally downward. This positioning allows the front end of the fin 30A to face downwind during operation, allowing condensed water to collect at the front end and to be discharged with high efficiency from the diagonally downward-facing peaks 31 and valleys 33.

As described above, the air conditioner 2 according to embodiment 3 is equipped with the heat exchanger 1A according to embodiment 1, so the heat exchange performance of the heat exchanger 1A is less likely to deteriorate, and the heating and cooling performance is also less likely to deteriorate. As a result, the air conditioner 2 can maintain high heating and cooling performance.

The manufacturing methods for the heat exchangers 1A and 1B and the air conditioner 2 according to the embodiments of the present disclosure have been described above, but the manufacturing methods for the heat exchangers 1A and 1B and the air conditioner 2 are not limited to this.

For example, in embodiments 1 and 2, at the downwind ends of the fins 30A and 30B provided in the heat exchangers 1A and 1B, both the corrugated peaks 31 and valleys 33 face diagonally downward. However, the fins 30A and 30B are not limited to this. At the end of the fins 30A and 30B in the direction in which the peaks 32 of the peaks 31 and the bottoms 34 of the valleys 33 extend, the peaks 32 need only be positioned in one direction relative to the connecting portions 35 and 36 connecting the peaks 31 and valleys 33. Alternatively, at the end of the fins 30A and 30B in the direction in which the peaks 32 of the peaks 31 and the bottoms 34 of the valleys 33 extend, the bottoms 34 need only be positioned in one direction relative to the connecting portions 35 and 36. Therefore, only one of the peaks 31 and valleys 33 may face downward, or the connecting portions 35 and 36 may be positioned upward, resulting in the peaks 31 and valleys 33 being positioned downward.

Here, it is desirable that the one direction is the direction in which gravity acts, for example, downward. Furthermore, it is desirable that the end in the direction in which the peak 32 of the peak portion 31 and the bottom 34 of the valley portion 33 extend is the end on the downwind side.

As mentioned above, the apex 32 or bottom 34 being located below the connecting portions 35, 36 means that a portion of the apex 32 or bottom 34 is located below the connecting portions 35, 36. More specifically, this means that a portion of the inner wall of the apex 32 or bottom 34 facing the inside of the corrugation is located below the connecting portions 35, 36.

Figure 18 is a cross-sectional view of a modified example of the fin 30A provided in the heat exchanger 1A according to embodiment 1. Figure 19 is a cross-sectional view of another modified example of the fin 30A. Figure 20 is a cross-sectional view of yet another modified example of the fin 30A.

As shown in Figure 18, the fin 30A may have a corrugated peak portion 31 and valley portion 33, with only the valley portion 33 facing downward, more specifically, with only the valley portion 33 tilting downward, so that of the peak portion 32 and bottom portion 34, only the bottom portion 34 is positioned lower than the connecting portions 35, 36. This is because condensed water can still be collected at the bottom portion 34 and drained.

In this case, the valley portion 33 faces downward linearly, but it may also face downward by curving. Also, although not shown, the fin 30A may have a top portion 32 and a bottom portion 34, with only the top portion 32 positioned lower than the connecting portions 35 and 36, as opposed to the configuration shown in Figure 18.

Also, as shown in Figure 19, in the fin 30A, the connecting portions 35, 36 connecting the peak portion 31 and the valley portion 33 and the adjacent portions adjacent thereto may protrude upward in a triangular shape in cross section. Furthermore, by positioning the connecting portions 35, 36 at the top, both the peak 32 and the bottom 34 may be positioned lower than the connecting portions 35, 36. Furthermore, as shown in Figure 20, the connecting portions 35, 36 and the adjacent portions adjacent thereto may protrude in a curved shape in cross section, more specifically, in an arc shape in cross section. In other words, they may protrude in a dimple shape. This is because these configurations also allow condensed water to be collected at the peak 32 and bottom 34 and drained.

The configurations shown in Figures 19 and 20 may be combined with embodiments 1 and 2 and the configuration shown in Figure 18.

Furthermore, in the configurations shown in Figures 19 and 20, it is advisable to provide a water-repellent layer on the upper surface of the upwardly protruding portion. This water-repellent layer may be achieved by applying flux and heating in the brazing process described in embodiment 1. By providing such a water-repellent layer, even if condensed water adheres to the upwardly protruding portion, the condensed water can be allowed to flow downward and be discharged from both the top 32 and the bottom 34. Naturally, it is also advisable to provide a water-repellent layer on the upper surface side of the fins 30A and 30B in embodiments 1 and 2.

Note that the configuration in which the connection portion 35 and its adjacent portion protrude upward as shown in Figures 19 and 20 is an example of the first protrusion defined in this disclosure. Furthermore, the configuration in which the connection portion 36 and its adjacent portion protrude upward is an example of the second protrusion defined in this disclosure.

Furthermore, only at the downwind ends of the fins 30A, 30B provided in the heat exchangers 1A, 1B, both the corrugated peaks 31 and valleys 33 face diagonally downward. However, the fins 30A, 30B are not limited to this. The shapes of the corrugated peaks 31 and valleys 33 need only be formed at the ends in the direction in which the peaks 32 of the peaks 31 and the bottoms 34 of the valleys 33 extend, and preferably at the ends located on the downwind side. Therefore, the above shapes may be formed at both the ends located on the downwind side and the ends located on the windward side.

Note that the term "end" refers to the portion including the end face, for example, the portion extending from the end face to approximately a few percent of the width of the fins 30A and 30B in the ventilation direction.

In embodiments 1 and 2, the front-to-rear width of the fins 30A, 30B is greater than the front-to-rear width of the heat transfer tube 20, and as a result, the fins 30A, 30B protrude further forward, i.e., downwind, than the heat transfer tubes 20, 21. However, the arrangement of the fins 30A, 30B is not limited to this. In the heat exchangers 1A, 1B, the relative positional relationship of the fins 30A, 30B to the heat transfer tubes 20, 21 is arbitrary.

Figure 21 is a perspective view of a modified example of heat exchanger 1A according to embodiment 1. Figure 22 is a perspective view of another modified example of heat exchanger 1A.

As shown in FIG. 21, the front-to-rear width of the fin 30A, i.e., its width in the Y direction, may be the same as the width of the heat transfer tube 20 in the Y direction, and the +Y face of the fin 30A may be aligned with the +Y face of the heat transfer tube 20 in the Y direction. Alternatively, as shown in FIG. 22, the Y direction width of the fin 30A may be smaller than the Y direction width of the heat transfer tube 20, and the +Y face of the fin 30A may be located on the -Y side of the +Y face of the heat transfer tube 20. Even in this configuration, condensed water can be discharged from the +Y end of the fin 30A, i.e., the downwind end.

1A, 1B Heat exchanger, 2 Air conditioner, 3 Compressor, 4 Fan, 5 Accumulator, 6 Four-way valve, 7 Housing, 11, 12 Header, 13, 14 Insertion hole, 20-22 Heat transfer tube, 30A, 30B Fin, 31 Peak portion, 32 Crest, 33 Valley portion, 34 Bottom, 35, 36 Connection portion, 37 Cut-out, 38 Through hole, 40 Fin forming device, 41, 42 Roller, 43, 44 Fin forming roller, 45, 46 Pitch narrowing roller, 47 Pitch widening roller, 50 Laminate, 100 Metal plate, 120 Heat transfer tube, 130 Fin, 150-153 Semi-finished fin, 311 Upper plate-shaped portion, 312 Lower plate-shaped portion, 331 Upper plate-shaped portion, 332 Lower plate portion, 410, 420 blade, A axial direction, A1, A2 arrows, D1 pipe axis direction, H1, H2 height, L solid line, P pitch, R rotation direction, W wind, θ angle.

Claims (4)

a step of sandwiching a plate-like body between a pair of rollers having intermeshing corrugated blades, and rotating the pair of rollers to bend the plate-like body into a corrugated shape having peaks and valleys, with a plurality of waves arranged in one direction in the order of the peaks, first connecting portions connecting the peaks and valleys, and the valleys, thereby forming a fin;
In the fin forming step, one end side of the pair of rollers in the axial direction processes one end of the plate-like body into a shape in which a top of the mountain portion is positioned in the one direction relative to the first connection portion.
A method for manufacturing a heat exchanger. a step of sandwiching a plate-like body between a pair of rollers having intermeshing corrugated blades, and rotating the pair of rollers to bend the plate-like body into a corrugated shape having peaks and valleys, with a plurality of waves arranged in one direction in the order of the peaks, first connecting portions connecting the peaks and valleys, and the valleys, thereby forming a fin;
a step of attaching the fins, which are oriented in the one direction, to a plurality of heat transfer tubes whose tube axes are oriented parallel to one another, by sandwiching the fins between the plurality of heat transfer tubes whose tube axes extend;
Equipped with
In the step of forming the fin, the engagement of one end of the pair of rollers is made deeper than the engagement of the other end, so that the distance from the top of the peak to the bottom of the valley at one end of the fin, which is in the direction in which the tops of the peaks and the bottoms of the valleys extend, is greater than the distance from the top to the bottom at the other end,
In the step of attaching the fins to the heat transfer tubes, the fins sandwiched between the heat transfer tubes are compressed in a direction in which the tube axes of the heat transfer tubes approach each other, thereby bending the one end of the fin more than the other end, and positioning the apex of the one end in the one direction relative to the first connection portion.
A method for manufacturing a heat exchanger. After the step of forming the fin, a step of enlarging or reducing the wave pitch of the formed fin is included.
A method for manufacturing the heat exchanger according to claim 1 or 2 . a step of assembling the heat exchanger manufactured by the method for manufacturing a heat exchanger according to claim 2 and a fan for blowing air to the heat exchanger into a housing,
In the step of assembling the heat exchanger and the fan to the housing, the blades of the fan are arranged to face the other end of the fins, so that the fan can blow air from the other end of the fins to the one end.
A method for manufacturing an air conditioner.