Patent Description:
Conventionally, a heat exchanger is known that has a structure in which the both ends of a flat tube (heat transfer tube) having a plurality of flow path holes therein is connected to a pair of headers, and the diversion of refrigerant to a plurality of flat tubes takes place in the headers. The plurality of flat tubes are stacked in a direction perpendicular to the refrigerant flow direction. Further, a plurality of fins are arranged between the pair of headers connected to the both ends of the flat tubes, and the flat tubes are connected to the plurality of fins. In this heat exchanger, heat is exchanged by the plurality of fins, between the refrigerant that flows through the flow path holes inside the flat tubes, and air that passes between the plurality of fins.

For example, as illustrated in <FIG>, a fin 111A of a heat exchanger 5A has a flat tube insertion portion 113A which is obtained by cutting out part of a ventilation portion 112A. A flat tube <NUM> is inserted into the flat tube insertion portion 113A of the fin 111A (in the heat exchanger 5A, a plurality of fins 111A are arranged in a direction orthogonal to the paper of <FIG>). A plurality of flow path holes 10A through which refrigerant flows, are provided inside the flat tube <NUM>.

Here, a structure is known in which, in order to secure a fin pitch P1 between adjacent fins 111A, as illustrated in <FIG>, part of the fins 111A is used as a cut and raised piece 114A, and the fin pitch P1 is secured by bringing the cut and raised piece 114A into contact with an adjacent fin 111A. The cut and raised piece 114A has a raised portion 115A which is raised from the fin 111A, and a folded portion 116A which is obtained by folding back the tip of the raised portion 115A. The portion of the fin 111A that is cut out over length W1 by forming the cut and raised piece 114A, is called the cutout remainder portion C1.

By way of an example, the cut and raised piece 114A is formed in the ventilation portion 112A of the fin 111A as illustrated in <FIG>, in the area corresponding to the cutout remainder portion C1, that is, in the position for forming the cut and raised piece 114A. However, the case of this example is undesirable in terms of ventilation resistance of the air that circulates between the fins 111A and the drainage of condensate that adheres to the surface of the fins 111A. In contrast, there is an example in which the cut and raised piece 114A is formed in the flat tube insertion portion 113A of the fin 111A, as illustrated in <FIG>. In the case of this example, the cut and raised piece 114A is disposed in a position of contact with the flat tube <NUM>, along the longitudinal direction of the flat tube <NUM>, so as to not interfere with the ventilation between the fins 111A, and not reduce the drainage of condensate (see, for example, Patent Literature <NUM>). Normally, the flat tube insertion portion 113A is formed by cutting out part of the fin 111A through pressing or the like (see <FIG>, the black areas of <FIG> are removed). However, in Patent Literature <NUM>, at least part of the flat tube insertion portion 113A remains as a cutout remainder portion C1 instead of being removed, and the cutout remainder portion C1 is bent in the direction perpendicular to the ventilation portion 112A to be used as the cut and raised piece 114A (see <FIG>).

However, in the structure of Patent Literature <NUM>, the cutout remainder portion C1, that is, the length of the cut and raised piece 114A that is bent and raised relative to the ventilation portion 112A, is limited to the width range of the flat tube insertion portion 113A, which corresponds to the thickness of the flat tube <NUM>. Therefore, in Patent Literature <NUM>, when the thickness of the flat tube <NUM> is smaller than the demanded fin pitch P1, the cutout remainder portion C1 is not adequately securable, and hence there has been the problem that the cut and raised piece 114A is not reachable to the adjacent fin 111A, and the fin pitch P1 between adjacent fins 111A is not properly securable. Patent Literature <NUM> describes a heat exchanger comprising refrigerant tubes vertically spaced apart from one another and heat exchanging fins being spaced apart from another in a longitudinal direction of the refrigerant tubes while being coupled to surfaces of the refrigerant tubes. Each heat exchanging fin includes fitting slots formed at one lateral end of the heat exchanging fin and vertically arranged to receive a plurality of refrigerant tubes. Moisture guide valleys extend vertically to downwardly guide moisture on the heat exchanging fin. Each moisture guide valley includes a first moisture guide valley arranged along a virtual line extending through a boundary between a curved portion of the corresponding fitting slot and each straight portion of the fitting slot, and a second moisture guide valley to guide moisture to the first moisture guide valley.

An object of the present invention, which was conceived in view of the foregoing problem, is to provide a heat exchanger in which a desired fin pitch can be secured irrespective of the thickness of a flat tube.

Advantageous embodiments are described in the dependent claim, the following description and the drawings. The wording of claim <NUM> defines the invention.

According to the present invention, a desired fin pitch can be secured irrespective of the thickness of a flat tube.

A mode for carrying out the present invention (referred to as the "embodiment" hereinbelow) will be described in detail hereinbelow on the basis of the accompanying drawings. Note that the same reference numbers are assigned to the same elements throughout the description of the embodiment.

<FIG> illustrates a configuration of an air conditioner <NUM> to which a heat exchanger <NUM> according to the embodiment of the present invention is applied. As illustrated in <FIG>, the air conditioner <NUM> is provided with an indoor unit <NUM> and an outdoor unit <NUM>. The indoor unit <NUM> is provided with an indoor heat exchanger <NUM>. The outdoor unit <NUM> is provided with a compressor <NUM>, an expansion valve <NUM>, and a four-way valve <NUM>, and the like, in addition to the outdoor heat exchanger <NUM>.

During a heating operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor <NUM> of the outdoor unit <NUM>, flows into the indoor heat exchanger <NUM> via the four-way valve <NUM>. Refrigerant flows in the direction of the black arrow in <FIG>. During the heating operation, the indoor heat exchanger <NUM> functions as a condenser, and the refrigerant, which exchanges heat with the air, condenses and liquefies. Thereafter, the high-pressure liquid refrigerant is depressurized by passing through the expansion valve <NUM> of the outdoor unit <NUM>, becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant, and flows into the outdoor heat exchanger <NUM>. The outdoor heat exchanger <NUM> functions as an evaporator, and the refrigerant, which exchanges heat with the outside air, is gasified. The low-pressure gas refrigerant is then drawn into the compressor <NUM> via the four-way valve <NUM>.

During a cooling operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor <NUM> of the outdoor unit <NUM>, flows into the outdoor heat exchanger <NUM> via the four-way valve <NUM>. The refrigerant flows in the direction of the white arrow in <FIG>. During the cooling operation, the outdoor heat exchanger <NUM> functions as a condenser, and the refrigerant, which exchanges heat with the outside air, condenses and liquefies. Thereafter, the high-pressure liquid refrigerant is depressurized by passing through the expansion valve <NUM> of the outdoor unit <NUM>, becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant, and flows into the indoor heat exchanger <NUM>. The indoor heat exchanger <NUM> functions as an evaporator, and the refrigerant, which exchanges heat with the air, is gasified. The low-pressure gas refrigerant is then drawn into the compressor <NUM> via the four-way valve <NUM>.

Although the heat exchanger according to the present embodiment can be applied to the indoor heat exchanger <NUM> and the outdoor heat exchanger <NUM>, the following description assumes that the heat exchanger according to the embodiment, is applied to the heat exchanger <NUM> of the outdoor unit <NUM>, which functions as an evaporator during a heating operation. Note that the heat exchanger <NUM> of the outdoor unit <NUM> may be used as a flat type as illustrated in <FIG>, or may be used in <FIG> by being formed in an L-shape. Normally, the L-shaped heat exchanger <NUM> is obtained by bending the heat exchanger <NUM> formed with a flat shape. The specific manufacturing process for manufacturing the L-shaped heat exchanger <NUM>, involves an assembly process of assembling the flat-type heat exchanger <NUM> using members that are surface-coated with a brazing material, a brazing process of placing the assembled flat-type heat exchanger <NUM> in a furnace and brazing same, and a bending process of bending the brazed flat-type heat exchanger <NUM> into an L shape. The heat exchanger of the present invention is described hereinbelow as a flat-type heat exchanger <NUM>.

<FIG> is a plan view to illustrate the heat exchanger <NUM> according to the embodiment. <FIG> is a front elevation view to illustrate the heat exchanger <NUM> according to the embodiment. As illustrated in <FIG>, the flat tube <NUM> has a flat shape with respect to the up-down direction, and is provided along the direction in which the refrigerant flows between the pair of headers <NUM> (along the longitudinal direction of the flat tube <NUM>), and air is circulated along the lateral direction of the flat tube <NUM>. Inside the flat tube <NUM>, a plurality of flow path holes 10A, through which the refrigerant flows along the longitudinal direction of the flat tube <NUM>, are formed in line with the air circulation direction (the lateral direction of the flat tube <NUM>). The heat exchanger <NUM> has a plurality of flat tubes <NUM> arranged in the up-down direction (perpendicular to the flow direction of the refrigerant) so that, among the sides of the flat tubes <NUM>, the sides that are wider along the longitudinal direction of the flat tubes <NUM> are opposite each other; a pair of left and right headers <NUM> connected to the both ends of the flat tubes <NUM>; and a plurality of fins <NUM> arranged in the direction intersecting the flat tubes <NUM> and joined to each of the flat tubes <NUM>. With regard to the plurality of flat tubes <NUM>, of two flat tubes <NUM> which are adjacent to each other in the up-down direction, the upper flat tube <NUM> in the drawings may be referred to as a first flat tube 11A, and the lower flat tube <NUM> in the drawings may be referred to as a second flat tube 11B. In addition to these flat tubes, the heat exchanger <NUM> has refrigerant piping connected to the header <NUM>, which connects to other elements of the air conditioner <NUM> and through which the refrigerant flows (not illustrated).

The flat tubes <NUM> are arranged in parallel in the up-down direction with a spacing S1 for air to pass through, and the both ends of the flat tubes <NUM> are connected to the pair of headers <NUM>. Specifically, in <FIG>, a plurality of flat tubes <NUM> along the left-right direction are arranged in the up-down direction with the predetermined spacing S1 through which air is circulated, and the both ends of each flat tube <NUM> are connected to the headers <NUM>.

The headers <NUM> are formed in a cylindrical shape, and a refrigerant flow path (not illustrated) is formed inside the headers <NUM> to divert the refrigerant, supplied to the heat exchanger <NUM>, into each of the plurality of flat tubes <NUM>, or to merge the refrigerant flowing out of each of the plurality of flat tubes <NUM>.

The fins <NUM> are formed in the shape of flat plates when viewed from the front of the heat exchanger <NUM>, and are arranged stacked in the longitudinal direction of the flat tubes <NUM> so as to intersect the flat tubes <NUM>. The plurality of flat tubes <NUM> are arranged in parallel with a gap S1 for air to pass through. A plurality of fins <NUM> along the up-down direction are arranged at a predetermined fin pitch P with respect to the longitudinal direction of the flat tubes <NUM> (the left-right direction in <FIG>).

Next, the main parts of the fins <NUM> of the heat exchanger <NUM> according to the present embodiment, will be described using <FIG>. Note that <FIG> provide an enlarged view of the area around flat tube insertion portions <NUM> of the fin <NUM> (described subsequently), and the flat tube <NUM> is not illustrated. A cut and raised piece <NUM> of this example has a raised portion <NUM> and a folded portion <NUM> obtained by folding back the tip of the raised portion <NUM>.

As illustrated in <FIG>, the fin <NUM> is provided with a ventilation portion <NUM>, a plurality of flat tube insertion portions <NUM>, and a plurality of cut and raised pieces <NUM>. The ventilation portion <NUM> is provided between the flat tube insertion portions <NUM>. The flat tube insertion portion <NUM> is formed by cutting out a part of the fin <NUM> through pressing or the like, except for the portion that forms part of the cut and raised piece <NUM> (the cutout remainder portion C1). The cut and raised piece <NUM> is configured from a portion corresponding to the cutout remainder portion C1 of the fin <NUM>, and a portion corresponding to the cutout portion C2 composed of part on the ventilation portion <NUM> side of the inner periphery opposite to the inner periphery of the flat tube insertion portion <NUM> where the cut and raised piece <NUM> is raised. The cutout portion C2 is a through portion that is contiguous with the flat tube insertion portion <NUM>. For the plurality of flat tube insertion portions <NUM>, of the two flat tube insertion portions <NUM> that are adjacent to each other in the up-down direction, the upper flat tube insertion portion <NUM> in <FIG> may be referred to as the first flat tube insertion portion 113A (corresponding to the first flat tube 11A), and a lower flat tube insertion portion <NUM> in <FIG> may be referred to as a second flat tube insertion portion 113B (corresponding to the second flat tube 11B).

The cut and raised piece <NUM> is bent at a first side <NUM> (the upper inner periphery in <FIG>) of the flat tube insertion portion <NUM>. The region C that constitutes the entire cut and raised piece <NUM> refers to the portion of the fin <NUM> that corresponds to the cutout remainder portion C1 of the flat tube insertion portion <NUM>, and to the portion that corresponds to the cutout portion C2 formed by cutting out part of the ventilation portion <NUM> on a second side <NUM> (the lower inner periphery in <FIG>) opposite the first side <NUM>. The length of the raised portion <NUM> is the length in the direction in which the raised portion <NUM> rises from the inner periphery of the flat tube insertion portion <NUM>, and is formed with the same length as the fin pitch P (see <FIG>). The length of the cutout remainder portion C1 is length W1 from the first side <NUM> to the second side <NUM>, and the length of the cutout portion C2 is length W2 up to the contour which is the greatest distance (the lower end of the arc-shaped cutout portion C2) from the second side <NUM>. In other words, the combined length of the raised portion <NUM> and the folded portion <NUM>, which constitute the whole of the cut and raised piece <NUM>, is length W, which is obtained by adding length W2 to length W1.

Note that, in <FIG>, the cut and raised piece <NUM> is provided on the first side <NUM>, which is the upper inner periphery in <FIG>, of the flat tube insertion portion <NUM>, but may of course also be provided on the second side <NUM>, which is the lower inner periphery in <FIG>. In other words, the cut and raised piece <NUM> may also be formed by being raised from the second side <NUM> of the flat tube insertion portion <NUM>.

The cross section of the cut and raised piece <NUM>, in a state where the cut and raised piece has been cut and bent from the fin <NUM>, is illustrated in <FIG> illustrates the relationship between the fin pitch P between adjacent fins <NUM> and the cut and raised piece <NUM>. The reference sign indicating the upper fin <NUM> in <FIG> is similarly applied to the lower fin <NUM> in <FIG>. Note that, in <FIG>, which illustrates the structure according to the present embodiment, the cutout portion C2 is expediently illustrated as part of the ventilation portion <NUM> for the sake of comparison with <FIG>, which illustrates a conventional structure. As illustrated in <FIG>, in a first fin 111a (the lower fin <NUM> in <FIG>), a cut and raised piece <NUM>, which has a portion corresponding to the cutout remainder portion C1 of the flat tube insertion portion <NUM> and a portion corresponding to the cutout portion C2 on the ventilation portion <NUM> side of the flat tube insertion portion <NUM>, is formed by bending the first side <NUM> of the flat tube insertion portion <NUM> (the inner periphery on the right side in <FIG>).

In the cut and raised piece 114A (see <FIG>) of the foregoing conventional structure, the region C of the fin 111A, which constitutes the cut and raised piece 114A, coincides with the portion (length W1) corresponding to the cutout remainder portion C1 of the flat tube insertion portion 113A. Hence, the fin pitch P1 in the conventional structure is limited to the area of the portion (length W1) corresponding to the cutout remainder portion C1. Therefore, the portion (length W1) corresponding to this cutout remainder portion C1 substantially corresponds to the thickness dimension of the flat tube <NUM>. Hence, if the desired fin pitch P1 is larger than the thickness dimension of the flat tube <NUM>, the length of the cut and raised piece 114A will be lacking by an amount equivalent to the portion corresponding to the cutout remainder portion C1 (length W1).

In contrast, as illustrated in <FIG>, the cut and raised piece <NUM> according to the present embodiment has length W1, which is obtained by adding a portion (length W2) corresponding to the cutout portion C2 provided on the second side <NUM>, which is part on the ventilation portion <NUM> side, to the portion (length W1) wherein the region C of the first fin 111a constituting the cut and raised piece <NUM> corresponds to the cutout remainder portion C1 of the flat tube insertion portion <NUM>. Therefore, even when the desired fin pitch P is larger than the dimension of the thickness of the flat tube <NUM>, the desired fin pitch P can be secured because it is possible, when the cut and raised piece <NUM> is cut and raised, to add a distance P2 to the fin pitch P1 corresponding to the thickness of the flat tube <NUM>.

Here, the cut and raised piece <NUM> does not necessarily have to be provided with the folded portion <NUM>, but it is preferable that the cut and raised piece <NUM> make surface contact with an adjacent second fin 111b via the folded portion <NUM> in order to prevent the cut and raised piece <NUM> from being crushed and to secure the fin pitch P more reliably.

Note that <FIG> do not indicate that the entire length of the portion corresponding to the cutout portion C2 (length W2) corresponds to the folded portion <NUM>. The length W2 of the portion corresponding to the cutout portion C2 may be set appropriately depending on the desired fin pitch P and the portion corresponding to the cutout remainder portion C1 of the flat tube insertion portion <NUM> (length W1), that is, the thickness of the flat tube <NUM>, and the portion corresponding to the cutout portion C2 may constitute part of the raised portion <NUM> and the folded portion <NUM> according to the desired fin pitch P.

Furthermore, the portion corresponding to the cutout remainder portion C1 and the portion corresponding to the cutout portion C2, are not limited to the shapes illustrated, and may be other shapes.

A fin reinforcement portion <NUM> will be described with reference to <FIG>. The fin <NUM> may be further provided with a fin reinforcement portion <NUM>, as illustrated in <FIG>, when the stiffness due to same being reduced by the formation of the cutout portion C2 needs to be enhanced.

The fin reinforcement portion <NUM> is provided in the ventilation portion <NUM> on the second side <NUM> of the flat tube insertion portion <NUM>, near the cutout portion C2, which is part of the region C cut out as part of the cut and raised piece <NUM>. The fin reinforcement portion <NUM> can be, for example, any of a bulging structure with a convex arc shape, a protruding structure with a convex shape with corners, or a corrugated structure obtained by placing a plurality of such structures in a row. <FIG> illustrates a roof-type protruding structure, but does not limit the shape of the fin reinforcement portion. The fins <NUM> may be provided with a bulging structure, a protruding structure or a corrugated structure, or the like, to improve heat transfer, and these structures may also be used as the fin reinforcement portion <NUM>.

In the present embodiment, as described above, the cut and raised piece <NUM> is configured from a portion corresponding to the cutout remainder portion C1 that is cut and raised by being bent on the first side <NUM> of the flat tube insertion portion <NUM>, and from a portion corresponding to the cutout portion C2, which is part of the ventilation portion <NUM> on the second side <NUM> opposite the first side <NUM> and which is cut and raised integrally with the portion corresponding to the cutout remainder portion C1. Thus, a cut and raised piece <NUM> larger than the thickness of the flat tube <NUM> can be formed on the inner periphery of the flat tube insertion portion <NUM>, irrespective of the thickness of the flat tube <NUM>, even when the desired fin pitch P is larger than the thickness of the flat tube <NUM>. It is thus possible to provide a heat exchanger <NUM> capable of securing a desired fin pitch P that is larger than the thickness of the flat tube <NUM>.

Although a preferred embodiment of the present invention has been described in detail hereinabove, the present invention is not limited to the foregoing embodiment, and various variations and modifications are possible within the scope of the gist of the present invention as disclosed in the patent claims. Although several variations are described hereinbelow, variations are not limited to such variations, and these variations can be combined within a reasonable scope.

For example, the fin reinforcement portion <NUM> of the fin <NUM> of the heat exchanger <NUM>, may also be formed as per the variations illustrated in <FIG> and <FIG>. <FIG> illustrates an example in which the fin reinforcement portion <NUM> is formed to follow the shape of the cutout portion C2. The mechanical strength of the fin <NUM> can be improved by providing the fin reinforcement portion <NUM> around the cutout portion C2 where the mechanical strength is reduced. It is noted that the arc-shaped fin reinforcement portion <NUM> here is formed along the semicircular cutout portion C2, but as described subsequently, the shape of the fin reinforcement portion <NUM> may be formed in any desired shape according to the shape of the cutout portion C2.

<FIG> illustrates an example in which an opposing surface 117a of the fin reinforcement portion <NUM> facing the cutout portion C2, is formed so as to be inclined in one direction relative to the up-down direction. Condensate readily accumulates in the cutout portion C2, where a gap arises adjacent to the flat tube <NUM> inserted into the flat tube insertion portion <NUM>. However, when condensate adheres over the cutout portion C2 and the fin reinforcement portion <NUM>, because the opposing surface 117a of the fin reinforcement portion <NUM> is inclined, condensate readily flows along the opposing surface 117a, thereby improving the drainage of condensate from the fin <NUM>.

Next, the cutout portion C2 of the fin <NUM> of the heat exchanger <NUM> may also be formed as per the variations illustrated in <FIG> and <FIG>. <FIG> illustrates an example in which the inner periphery of the cutout portion C2 is cut out so as to have an acute angle portion θ. The acute angle portion θ is formed, for example, by a vertical side along the up-down direction and an inclined side that is inclined relative to the up-down direction. By forming the cutout portion C2 into a shape with the acute angle portion θ, condensate accumulated in the cutout portion C2 concentrates at the acute angle portion θ, thereby facilitating drainage of the condensate from the acute angle portion θ and improving the drainage of condensate from the fin <NUM>. Furthermore, in this example, since the angle between the inclined side of the cutout portion C2 and the second side <NUM> is smaller, the cutout portion C2 also acts as a guide when inserting the flat tube <NUM> into the flat tube insertion portion <NUM>, thus improving the assemblability of the heat exchanger <NUM>.

Claim 1:
A heat exchanger (<NUM>), comprising:
a plurality of flat tubes (<NUM>) that are stacked in a direction perpendicular to a refrigerant flow direction; and
a plurality of fins (<NUM>) that have a first flat tube insertion portion (113A) into which a first flat tube (11A) among the plurality of flat tubes (<NUM>) is inserted, and a second flat tube insertion portion (113B) into which a second flat tube (11B) adjacent to the first flat tube (11A) is inserted,
wherein a first fin (111a) among the plurality of fins (<NUM>) comprises: an inner periphery of the first flat tube insertion portion (113A) where the first flat tube (11A) comes into contact with the first fin (111a); and comprises a cut and raised piece (<NUM>) for spacing a fin pitch (P) between the first fin (111a) and an adjacent second fin (111b), the cut and raised piece (<NUM>) being formed on a first inner periphery (<NUM>) located at either side in a thickness direction of the first flat tube (11A) in the inner periphery of the first flat tube insertion portion (113A); the heat exchanger being characterized by a cutout portion (C2) obtained by cutting out a second inner periphery (<NUM>) in the thickness direction, the cutout portion (C2) being formed on the second inner periphery (<NUM>) opposing the first inner periphery (<NUM>) of the first flat tube insertion portion (113A),
wherein the cut and raised piece (<NUM>) is formed to have a length extending from the first inner periphery (<NUM>) to the cutout portion (C2), and is formed to extend from the first inner periphery (<NUM>) to the second fin (111b), thereby having a raised portion (<NUM>) of the same length as the fin pitch (P), and a folded portion (<NUM>) that is folded back at the tip of the raised portion (<NUM>) and that is in contact with the second fin (111b).