JP2012202572A - Fin-and-tube heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fin-and-tube heat exchanger which secure sufficient connection between a fin and a heat transfer tube by fixing the fin and heat transfer tube by brazing, and hardly causes a variation in a distance between adjacent fins.SOLUTION: The fin-and-tube heat exchanger is constituted in such a way that collars 18 erected along the periphery of an attachment slit 16 on upper surfaces of fins 12 are inclined outward and front ends of inclined portions are brought into contact with lower surfaces of adjacent fins 12.

Description

  The present invention relates to a fin-and-tube heat exchanger, and more particularly to a fin-and-tube heat exchanger suitably used in an air conditioner such as a home air conditioner or an automobile air conditioner.

  Conventionally, heat exchangers that operate as evaporators or condensers have been used in refrigerators, heat pump water heaters, etc., in addition to air conditioning equipment such as home air conditioners, automotive air conditioners, and packaged air conditioners. In indoor air conditioners and commercial packaged air conditioners, fin-and-tube heat exchangers having a structure in which fins are assembled to heat transfer tubes are most commonly used.

  Such fin-and-tube heat exchangers generally have a structure in which heat transfer tubes are inserted perpendicularly to a plurality of fins (outer surface fins) and the plurality of fins and heat transfer tubes are joined. Has been. In the heat exchanger having such a structure, the refrigerant is circulated in the heat transfer tube, while air as a heat exchange fluid is caused to flow through the gaps between the plurality of fins in a direction perpendicular to the heat transfer tube. Thus, heat exchange is performed between the refrigerant and the air.

  And the fin which comprises such a fin and tube type heat exchanger is generally comprised from the board | plate material made from aluminum or aluminum alloy. In addition, as one of the heat transfer tubes used in the fin-and-tube heat exchanger, a flat multi-hole tube having a structure in which a flat tube interior is divided into a plurality of flow paths by a plurality of partition walls is provided. ,Are known. In this flat multi-hole tube, in general, those obtained by extrusion of a port hole from aluminum or an aluminum alloy as a material are generally used because of its ease of manufacture. As described above, since the fins and heat transfer tubes constituting the heat exchanger are all made of aluminum material, the fin-and-tube heat exchanger can be effectively reduced in size and weight. In addition, there is an advantage that the cost is lower than that of a copper material.

  By the way, as a typical joining method of the fin and the heat transfer tube in such a fin-and-tube heat exchanger, a heat transfer tube inserted into a mounting hole provided in the fin is used for mechanical expansion or hydraulic pressure. Expanding the tube by expanding the tube, etc., a method of expanding the tube so that the inner surface of the mounting hole and the outer peripheral surface of the heat transfer tube are in close contact with each other, a method called a crimping method in which the heat transfer tube is press-fitted into the mounting hole of the fin, A brazing method or the like in which the gap between the outer peripheral surface of the heat transfer tube inserted into the mounting hole and the mounting hole is filled with a brazing material is well known. Among such joining methods, in the case of a fin-and-tube heat exchanger using a flat multi-hole tube as a heat transfer tube, it is difficult to expand by a mechanical tube expansion method. Many brazing methods are used.

  For example, Japanese Patent Laid-Open No. 5-87480 (Patent Document 1) shows an example of a heat exchanger manufactured by a knuckling method. Specifically, it is a fin-and-tube heat exchanger in which a straight pipe portion of a meandering refrigerant tube (heat transfer tube) is press-fitted into both ends receiving holes of a refrigerant tube insertion long hole provided in a plate fin. When the straight tube portion of the refrigerant tube is press-fitted into the peripheral portion of the both-end receiving hole in the plate fin, it is repelled in the radial direction of the receiving hole and restored after the press-fitting to press contact with the outer periphery of the straight tube portion of the refrigerant tube. It has been clarified that a collar portion is provided. According to such a heat exchanger, the refrigerant tube can be easily pressed into the fin, and the bonding strength between the refrigerant tube and the plate fin is increased.

  However, in the heat exchanger described in Patent Document 1, since the predetermined collar portion is provided at the peripheral edge portion of the both-end receiving hole in the plate fin, the bonding strength between the refrigerant tube and the plate fin is increased. However, there is a microscopic gap between the refrigerant tube and the plate fin, so there is a risk that sufficient heat transfer, in other words, sufficient heat exchange performance cannot be exhibited. is there.

  On the other hand, in Japanese Patent Application Laid-Open No. 2007-155181 (Patent Document 2), a cut-and-raised portion is provided around a fitting groove provided in a flat fin, and a plurality of such fins are stacked in parallel at a constant pitch. In the fitting groove, a fin-and-tube type constructed so that the outer periphery of the cross section in which the refrigerant flows is inserted into a heat transfer tube having a flat cross section at a substantially right angle so that the fin and the heat transfer tube are closely bonded. A heat exchanger is revealed. According to such a heat exchanger, it can be assembled without damaging the surface agent applied to the outer surface of the heat transfer tube at the edge of the fin, and the contact area between the fin and the heat transfer tube is increased by the cut and raised portion. By doing so, it is said that the heat transfer coefficient can be improved efficiently.

  In JP 2010-156525 A (Patent Document 3), plate-like fins made of an aluminum alloy are laminated at a predetermined interval, and a groove provided in the plate-like fin is along the longitudinal direction in the longitudinal direction. A flat heat transfer tube provided with a refrigerant flow path is inserted, the solder layer provided on the outer surface of the front edge of the heat transfer tube is melted, and the heat transfer tube is fixed to the plate fin by the solder. The exchanger is revealed. Therefore, it is said that such a heat exchanger is easy to manufacture, can reduce costs, and can provide a highly reliable heat exchanger.

  However, in the heat exchangers disclosed in Patent Document 2 and Patent Document 3, when the fins and the heat transfer tubes are fixed by brazing, the adjacent fins are caused by a brazing defect. The distance between them may not be the desired distance. Specifically, when producing a heat exchanger in which the distance between adjacent fins is small (narrow), when brazing is performed in a state where the distance between fins is small (narrow), the heat transfer tubes and the fins are joined. The brazing material (solder) may enter not only the gap between the heat transfer tube and the fin but also between the adjacent fins and the fins may stick to each other.

  The problem that the distance between adjacent fins does not reach the desired distance is due to an external force being applied to the fins, for example, when brazing the fins and the heat transfer tubes other than those caused by the above-mentioned poor brazing. For example, the distance between adjacent fins becomes larger (or smaller) than the target distance, and the fin is fixed in such a state. And in the heat exchanger in which the distance between adjacent fins is disturbed, there has been a problem that the ventilation resistance of air as a heat exchange medium increases and the heat exchange performance deteriorates. It is.

JP-A-5-87480 JP 2007-155181 A JP 2010-156525 A

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is a fin-and-tube heat exchanger of an air conditioner, and a fin by brazing. In addition, it is an object of the present invention to provide a fin-and-tube heat exchanger in which sufficient bonding between the fins and the heat transfer tubes can be ensured by fixing the heat transfer tubes, and the distance between adjacent fins is hardly disturbed.

  In the present invention, in order to solve such a problem, in a large number of plate-like fins made of aluminum or an alloy thereof stacked and spaced apart from each other by a predetermined distance, the corresponding peripheral edge portions are used. Fin-and-tube heat exchangers that are assembled by fitting flat multi-hole tubes made of aluminum or its alloys into the assembly slits in the shape of side openings that are provided so as to open. Then, at least the tip side portion of the collar portion erected around the assembly slit on the upper surface of the fin is inclined outward, and the tip portion of the inclined portion is brought into contact with the lower surface of the adjacent fin. A gist of a fin-and-tube heat exchanger characterized in that the distance between adjacent fins is defined by A.

  According to one of the preferred embodiments of the fin-and-tube heat exchanger according to the present invention, the collar portion is inclined outward from the base portion as a whole, and the inclined portion is Is formed.

  Moreover, according to one of the other preferable aspects of the fin and tube type heat exchanger which concerns on this invention, the said inclination part is outward in the angle of 5 degrees-45 degrees with respect to the plate | board surface of a fin. It is tilted.

  Furthermore, according to another desirable aspect of the fin-and-tube heat exchanger of the present invention, the assembly slit is formed in a U-shape.

  As described above, in the fin-and-tube heat exchanger according to the present invention, at least the tip side portion of the collar portion erected around the assembly slit on the upper surface of the fin is inclined outward, When the tip of the inclined portion is brought into contact with the lower surface of the adjacent fin, the distance between the adjacent fins is defined, so that when the fin and the flat multi-hole tube are brazed, Even when an unexpected external force is applied to the fins, the distance between adjacent fins is sufficiently secured, and the heat exchanger is less likely to cause a disturbance in the distance between adjacent fins. It is.

  In addition, since at least the tip side portion of the collar portion erected around the fin assembly slit is inclined outward, there is a gap between the tip side portion of the collar portion and the flat multi-hole tube. When a gap is formed and the fin and the flat multi-hole tube are brazed in such a state, the molten brazing material enters the gap. As described above, the brazing material enters the gap between the tip side portion of the collar portion and the flat multi-hole tube, so that the bonding between the fin and the flat multi-hole tube becomes sufficient, and the heat obtained The exchanger exhibits excellent heat transfer properties (heat exchange properties). In addition, even if there is a somewhat large amount of molten brazing material, it can be accepted in the gap, so the occurrence of the disturbance in the distance between adjacent fins due to the above-mentioned poor brazing is also effective. Can be suppressed.

It is a perspective explanatory view showing an example of a fin and tube type heat exchanger according to the present invention. It is a perspective explanatory view which shows the fin which comprises the fin and tube type heat exchanger shown by FIG. FIG. 3 is an explanatory cross-sectional view showing an enlargement of an assembly slit portion of the fin shown in FIG. 2. It is a perspective explanatory drawing which expands and shows the junction part of the fin of the fin and tube type heat exchanger according to this invention, and a flat multi-hole tube. It is an isometric view explanatory drawing which shows another example of the fin which comprises the fin and tube type heat exchanger according to this invention. FIG. 6 is an enlarged cross-sectional explanatory view showing an assembly slit portion of the fin shown in FIG. 5.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 schematically shows one embodiment of a fin-and-tube heat exchanger according to the present invention in a perspective view. In this case, the heat exchanger 10 is a slit in which one flat multi-hole tube 14 is provided in the fin 12 with respect to the plurality of fins 12 stacked and arranged in parallel with each other at a predetermined distance. After being inserted into the shaped assembly slit 16, it is formed by being fixed by brazing.

  More specifically, the fin 12 is formed of a metal material made of aluminum or an aluminum alloy, as in the prior art, and has a rectangular plate shape as shown in FIG. It is said to be a fin. An assembly slit 16 into which the flat multi-hole tube 14 is assembled is provided at a substantially central portion of the fin 12 and extends from the end of one side of the rectangular fin 12 toward the opposite side. It is formed as a slit. Further, a collar portion 18 standing at a predetermined height is formed integrally with the fin 12 around the assembly slit 16. The thickness (t) of the fin 12 is appropriately determined according to the size of the flat multi-hole tube 14 to be assembled, the required performance of the heat exchanger 10, and the like. Is 0.080 mm or more and 0.120 mm or less.

  The collar portion 18 formed on the peripheral edge of the assembly slit 16 has a predetermined angle outward from the base so that the distance from the flat multi-hole tube 14 gradually increases toward the tip. In addition to being inclined at θ, the height: h of the collar portion 18 is configured to be a distance (design value) between adjacent fins 12 in the heat exchanger 10. That is, as shown in an enlarged view in FIG. 3, the width: a of the upper opening of the collar portion 18 is larger (wider) than the width: b of the base portion, so that it rises from the peripheral portion of the assembly slit 16. The collar portion 18 is inclined at an angle θ with respect to the plate surface of the fin 12 toward the outer side of the assembly slit 16 toward the tip, and the height of the collar portion 18 is h. The distance between adjacent fins in the target heat exchanger 10 is the same.

  Thus, when the flat multi-hole tube 14 is assembled to the assembly slit 16 of the fin 12 by forming the collar portion 18 so as to incline toward the outside of the assembly slit 16, the collar portion An effective gap is formed between the flat multi-hole pipe 14 and the flat multi-hole pipe 14, and when the fins 12 and the flat multi-hole pipe 14 are brazed in such a state, the molten brazing material enters the gap. . Due to the penetration of the brazing material, the bonding between the fins 12 and the flat multi-hole tube 14 is sufficiently secured, and the obtained heat exchanger 10 exhibits excellent heat transfer properties (heat exchange properties). Further, even if the molten brazing material is somewhat large, it can be accepted in the gap, so that the distance between adjacent fins due to brazing failure is in other words, that is, the brazing material is The occurrence of disturbance in the distance between the fins by entering the gap between the adjacent fins 12 and fixing the adjacent fins 12 to each other is effectively suppressed.

  Further, since the height h of the collar portion 18 is the distance (design value) between adjacent fins in the target heat exchanger 10, the fin 12 having such a collar portion 18 is Assembling with the flat multi-hole tube 14 is performed so that the front end abuts the lower surface of the adjacent fin 12 (the surface on which the collar portion 18 is not erected), and in this state the fin 12 and the flat multi-hole When the pipe 14 is brazed, even if an unexpected external force is applied to the fins during the brazing, the distance between the fins is sufficiently secured. The occurrence of turbulence is effectively suppressed.

  The inclination angle θ of the collar portion 18 is preferably in the range of 5 ° to 45 °. If θ is too small, the target distance between the fins may not be ensured when an unexpected external force is applied. On the other hand, if θ is too large, the color may be increased when an unexpected external force is applied. This is because it becomes difficult to suppress the occurrence of the disturbance of the inter-fin distance because the portion 18 further opens outward.

  Further, the height 18 of the collar portion 18 is generally about 1.2 to 3.0 mm. If the height of the collar portion 18 is too low, the effect of preventing the occurrence of a disturbance in the distance between the fins may be reduced. If the height of the collar portion 18 is too high, the color portion is formed by ironing or the like described later. This is because the thickness of 18 becomes thin and easily deforms, and it becomes difficult to suppress the occurrence of disturbance in the inter-fin distance.

  By the way, the fin 12 in which such a collar portion 18 is formed can be advantageously obtained by, for example, the following known processing method. That is, first, an aluminum plate made of predetermined aluminum or aluminum alloy is pressed to obtain the outer shape of the fin 12, and further, the assembly slit 16 corresponding to the outer surface shape of the flat multi-hole tube 14 and its assembly A material in which a collar forming portion standing at a predetermined height from the peripheral edge portion of the assembly slit 16 is integrally formed by cutting and raising the material of the attachment slit portion is prepared. Thereafter, ironing is performed on such a color forming portion, and further, pressing is performed with a predetermined conical punch from above the color forming portion, so that the tip side portion is angled outward: θ Thus, the collar portion 18 having a height of h is formed.

The ironing process for forming the collar portion 18 is performed once or so that the finally given height h of the collar portion 18 is the same as the target distance (design value) between the fins. Performed multiple times. One ironing process is preferably performed at an ironing rate of 50% or less. The ironing rate is calculated from the following equation.
[Steeling rate (%)] = {(BA) / B} × 100 (%) (formula)
However, A is the thickness of the collar part after ironing, and B is the thickness of the collar part before ironing.

  On the other hand, the flat multi-hole tube 14 is formed by using a metal material made of aluminum or an aluminum alloy and applying a known processing method such as a port hole extrusion process to the metal material. In addition, in FIG. 1, it is set as the multi-hole pipe which exhibits the flat shape by which the seven holes 20 extended in a pipe-axis direction are formed. Further, the thickness t ′ of the flat multi-hole tube 14 is generally set to about 1.0 to 4.0 mm.

  Then, using such a flat multi-hole tube 14 and the fins 12, a plurality of the fins 12 are parallel to each other and the collar portion 18 in a state where the assembly slits 16 formed on each of the fins 12 are aligned. The flat multi-hole tube 14 is fitted into the matching assembling slit 16 so that the tip of each of the fins is in contact with the lower surface of the adjacent fin 12 (the surface on which the collar portion 18 is not erected). Then, after assembling them, the target fin-and-tube heat exchanger 10 is manufactured by brazing by a method such as placing it. Although not shown here, predetermined headers are respectively connected to both ends of the flat multi-hole tube 14, and seven holes 20 of the flat multi-hole tube 14, i.e., a refrigerant extending in the tube axis direction. Seven flow paths to be circulated are combined on the refrigerant inlet side and the outlet side, respectively, to constitute a fin-and-tube heat exchanger 10.

  According to the fin-and-tube heat exchanger 10 configured according to the present invention, the collar portion 18 is placed on the lower surface of the adjacent fin 12 (the surface on the side where the collar portion 18 is not erected). Since the distance between the fins is regulated by the contact, an unexpected external force is applied to the fin when brazing the fin and the flat multi-hole tube. However, the distance between the fins is sufficiently secured, and the occurrence of the disturbance in the distance between the fins is effectively suppressed.

  Further, since the collar portion 18 is inclined outwardly at an angle: θ, a gap is formed between the collar portion 18 and the flat multi-hole tube. In such a state, the fins and the flat multi-holes are formed. When the tube is brazed, the molten brazing material penetrates into the gap. As described above, the brazing material enters the gap between the tip side portion of the collar portion and the flat multi-hole tube, so that the bonding between the fin and the flat multi-hole tube becomes sufficient, and the heat obtained The exchanger exhibits excellent heat transfer properties (heat exchange properties). In addition, even if the molten brazing material is somewhat large, since it can be accepted in the gap, occurrence of disturbance in the inter-fin distance due to poor brazing can be effectively suppressed. It is.

  As described above, one of the representative embodiments of the present invention has been described in detail. However, this is merely an example, and the present invention is not limited in any way by the specific description according to such an embodiment. It should be understood that this is not to be construed as a matter of course.

  For example, in the above-described embodiment, the collar portion 18 is inclined outward from the base portion. However, in the present invention, at least the tip side portion of the collar portion is inclined outward. That is enough. Specifically, as shown in FIG. 5 and FIG. 6, the collar portion 22 is composed of an upright portion 24 standing upright from a plate surface of the fin 28 and a tip portion 26 inclined outward. Even if it exists, it can employ | adopt in the heat exchanger of this invention.

  Further, in the above-described embodiment, the U-shaped assembling slit 16 is illustrated as the side opening void-shaped assembling slit. However, in addition to such a shape, for example, a U-shaped It is also possible to adopt an assembling slit shape having a shape corresponding to the thickness or outer surface shape of the flat multi-hole tube 14 to be assembled, such as a V shape or a V shape.

  Furthermore, as a method of brazing the fins 12 and the flat multi-hole tube 14, a brazing method by placing brazing was illustrated, but in addition to such a method, for example, a brazing material is previously clad on the surface of an aluminum plate. Various known brazing methods such as forming the fins 12 using a brazed sheet, and brazing the fins 12 and the flat multi-hole tube 14 can be employed. Even in the brazing method, the effect of the present invention is advantageously exhibited.

  In addition, although not listed one by one, the present invention is implemented in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 10 Heat exchanger 12 Fin 14 Flat multi-hole tube 16 Assembling slit 18 Collar part 20 Hole 22 Collar part 24 Upright part 26 Tip part 28 Fin

Claims (4)

Assembling slits in the shape of side openings are provided in a large number of plate-like fins made of aluminum or an alloy thereof laminated at a predetermined distance from each other so as to open at their corresponding peripheral edges. On the other hand, a flat multi-hole tube made of aluminum or an alloy thereof is fitted into a fin-and-tube heat exchanger assembled,
By adhering at least the tip side portion of the collar portion erected on the upper surface of the fin around the assembly slit to the outside and bringing the tip portion of the inclined portion into contact with the lower surface of the adjacent fin, A fin-and-tube heat exchanger characterized in that the distance between the fins is defined.   The fin-and-tube heat exchanger according to claim 1, wherein the collar portion is inclined outward from the base portion as a whole to form the inclined portion.   The fin-and-tube heat exchanger according to claim 1 or 2, wherein the inclined portion is inclined outward at an angle of 5 ° to 45 ° with respect to the plate surface of the fin. The fin-and-tube heat exchanger according to any one of claims 1 to 3, wherein the assembly slit is formed in a U-shape.

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