Patent Description:
A refrigerant cycle apparatus such as an air conditioner conventionally includes a heat exchanger provided with a heat transfer tube allowing a refrigerant to flow therein and connected to a header.

An exemplary heat exchanger described in Patent Literature <NUM> (<CIT>) includes a header constituted by a plurality of laminated plate-shaped members. The header includes bare materials provided with no brazing filler material, and clad materials having front and rear surfaces each provided with the brazing filler material, and the bare materials and the clad materials are laminated alternately and are joined by brazing.

<CIT> (which forms the basis for the preamble of claim <NUM>) discloses a bundle including a plurality of tubes, a first header box and a second header box. <CIT> discloses a heat exchanger comprising a plurality of flat heat exchange tubes, two header tanks, wherein each header tank includes a tubular tank body having a plurality of tube insertion holes.

When the plurality of members mentioned above is joined by brazing, a brazing filler material positioned far from a heat source for provision of heat is less likely to melt in comparison to a brazing filler material positioned close to the heat source, to possibly cause defective brazing.

It is an object of the present disclosure to provide a heat exchanger configured to inhibit defective brazing of a header constituted by a plurality of members, a heat pump device, and a method of manufacturing the heat exchanger.

A heat exchanger according to the invention is defined in claim <NUM>.

A brazing layer between the second member and the third member has a melt rate, at a predetermined temperature, being larger than a melt rate, at the predetermined temperature, of at least one of a brazing layer between the first member and the second member and a brazing layer between the first member and the third member.

The predetermined temperature should not be limited and, for example, may be a temperature at which a melt is generated at both a brazing layer between the second member and the third member and the brazing layer between the first member and the second member, may be a temperature at which a melt is generated at both the brazing layer between the second member and the third member and the brazing layer between the first member and the third member, or may be a temperature at which a melt is generated at all the brazing layer between the second member and the third member, the brazing layer between the first member and the second member, and the brazing layer between the first member and the third member. The temperature may be, for example, <NUM> or more, or <NUM> or more. The predetermined temperature has an upper limit that should not be limited, and the upper limit may be <NUM> or less and can be <NUM> or less. An ambient temperature in a furnace should not be limited, and may be exemplarily <NUM> or more and <NUM> or less.

Though not limited, the heat exchanger may be constructed such that the header has a vertical or horizontal longitudinal direction.

The heat exchanger can achieve an excellent joining state of brazing between the second member and the third member, even in a case where the brazing layer between the second member and the third member is lower in temperature during brazing than at least one of the brazing layer between the first member and the second member and the brazing layer between the first member and the third member.

According to the invention, the brazing layer between the second member and the third member has a silicon content larger than a silicon content of at least one of the brazing layer between the first member and the second member and the brazing layer between the first member and the third member.

The brazing layer between the second member and the third member preferably contains a silicon alloy larger in silicon content than a silicon alloy in at least one of the brazing layer between the first member and the second member and the brazing layer between the first member and the third member.

The predetermined temperature should not be limited and, for example, may be a temperature at which a melt is generated at both a brazing layer between the second member and the third member and the brazing layer between the first member and the second member, may be a temperature at which a melt is generated at both the brazing layer between the second member and the third member and the brazing layer between the first member and the third member, or may be a temperature at which a melt is generated at all the brazing layer between the second member and the third member, the brazing layer between the first member and the second member, and the brazing layer between the first member and the third member. The temperature may be, for example, <NUM> or more, or <NUM> or more. The predetermined temperature has an upper limit that should not be limited, and the upper limit may be <NUM> or less and can be <NUM> or less. Ambient temperature in a furnace should not be limited, and may be exemplarily <NUM> or more and <NUM> or less.

According to the invention, a heat exchanger is defined in which the brazing layer between the second member and the third member is disposed inside a space defined by the brazing layer between the first member and the second member and the brazing layer between the first member and the third member. The heat exchanger thus achieves an excellent joining state of brazing between the second member and the third member even in a case where the brazing layer between the second member and the third member receives less heat, during brazing, than at least one of the brazing layer between the first member and the second member and the brazing layer between the first member and the third member.

According to the invention, the first member has a first portion having a plate shape. The first portion has a plurality of first openings into which the heat transfer tubes are inserted. The third member is a plate-shaped member having a plurality of second openings into which the heat transfer tubes are inserted. The first portion and the third member are laminated in a thickness direction.

The heat exchanger achieves joining by brazing of the inserted heat transfer tubes in the first openings in the first portion of the first member. The first member and the third member are laminated in the thickness direction to secure a total thickness for improvement in strength of the header. This configuration allows the first member to be thinned while securing strength of the header, for less friction between circumferential surfaces of the heat transfer tubes and the first openings upon insertion of the heat transfer tubes.

In the heat exchanger according to the invention, in a view in an extending direction of the heat transfer tubes, each of the first openings has an outline positioned inside an outline of a corresponding one of the second openings.

In the heat exchanger, any excessive brazing filler material around ends of the heat transfer tubes during brazing can be shifted into regions outside the heat transfer tubes and inside the second openings of the third member. This inhibits the brazing filler material from blocking flow paths in the heat transfer tubes.

As an optional feature, each of the first member, the second member, and the third member contains aluminum or an aluminum alloy.

As an optional feature, each of the first member, the second member, and the third member has a thickness equal to or less than <NUM>.

Each of the first member, the second member, and the third member has a thickness equal to or less than <NUM> in the heat exchanger, and each of the members can thus be easily formed into a specific shape.

A heat pump device equipped with the heat exchanger of the invention is also defined.

A method of manufacturing a heat exchanger according to the invention is defined in claim <NUM>.

The predetermined temperature should not be limited. For example, it may be a temperature at which a melt is generated at both the clad layer of the first member and the clad layer of the third member, and may be, for example, <NUM> or more, or <NUM> or more. The predetermined temperature has an upper limit that should not be limited, and the upper limit may be <NUM> or less and can be <NUM> or less. Ambient temperature in a furnace should not be limited, and may be exemplarily <NUM> or more and <NUM> or less.

The method of manufacturing the heat exchanger can provide the heat exchanger in an excellent joining state of brazing between the second member and the third member even in a case where the clad layer of the third member is lower in temperature than the clad layer of the first member during brazing by heating the first member, the second member, and the third member.

Description will be made hereinafter to an air conditioner according to an embodiment, including a heat exchanger of the present disclosure.

An air conditioner <NUM> will be described with reference to drawings.

<FIG> is a schematic configuration diagram of the air conditioner <NUM> including, as an outdoor heat exchanger <NUM>, a heat exchanger according to an embodiment of the present disclosure.

The air conditioner <NUM> (exemplifying a heat pump device) is configured to achieve a vapor compression refrigeration cycle to cool and heat an air conditioning target space. Examples of the air conditioning target space include a space in a building such as an office building, a commercial facility, or a residence. The air conditioner merely exemplifies a refrigerant cycle apparatus. The heat exchanger according to the present disclosure may be included in a different refrigerant cycle apparatus such as a refrigerator, a freezer, a hot-water supplier, or a floor heater.

As depicted in <FIG>, the air conditioner <NUM> principally includes an outdoor unit <NUM>, an indoor unit <NUM>, a liquid-refrigerant connection pipe <NUM>, a gas-refrigerant connection pipe <NUM>, and a control unit <NUM> configured to control devices constituting the outdoor unit <NUM> and the indoor unit <NUM>. The liquid-refrigerant connection pipe <NUM> and the gas-refrigerant connection pipe <NUM> are refrigerant connection pipes connecting the outdoor unit <NUM> and the indoor unit <NUM>. The outdoor unit <NUM> and the indoor unit <NUM> are connected via the liquid-refrigerant connection pipe <NUM> and the gas-refrigerant connection pipe <NUM> to constitute a refrigerant circuit <NUM> in the air conditioner <NUM>.

The air conditioner <NUM> depicted in <FIG> includes one indoor unit <NUM>. The air conditioner <NUM> may alternatively include a plurality of indoor units <NUM> connected parallelly to the outdoor unit <NUM> by the liquid-refrigerant connection pipe <NUM> and the gas-refrigerant connection pipe <NUM>. The air conditioner <NUM> may still alternatively include a plurality of outdoor units <NUM>. Still alternatively, the air conditioner <NUM> may be of an integral type including the outdoor unit <NUM> and the indoor unit <NUM> that are formed integrally with each other.

The outdoor unit <NUM> is disposed outside the air conditioning target space, such as on a roof of a building or adjacent to a wall surface of a building.

The outdoor unit <NUM> principally includes an accumulator <NUM>, a compressor <NUM>, a four-way switching valve <NUM>, the outdoor heat exchanger <NUM>, an expansion mechanism <NUM>, a liquid-side shutoff valve <NUM>, a gas-side shutoff valve <NUM>, and an outdoor fan <NUM> (see <FIG>).

The outdoor unit <NUM> principally includes, as a refrigerant pie connecting various devices constituting the refrigerant circuit <NUM>, a suction pipe <NUM>, a discharge pipe <NUM>, a first gas refrigerant pipe <NUM>, a liquid refrigerant pipe <NUM>, and a second gas refrigerant pipe <NUM> (see <FIG>). The suction pipe <NUM> connects the four-way switching valve <NUM> and a suction side of the compressor <NUM>. The suction pipe <NUM> is provided with the accumulator <NUM>. The discharge pipe <NUM> connects a discharge side of the compressor <NUM> and the four-way switching valve <NUM>. The first gas refrigerant pipe <NUM> connects the four-way switching valve <NUM> and a gas side of the outdoor heat exchanger <NUM>. The liquid refrigerant pipe <NUM> connects a liquid side of the outdoor heat exchanger <NUM> and the liquid-side shutoff valve <NUM>. The liquid refrigerant pipe <NUM> is provided with the expansion mechanism <NUM>. The second gas refrigerant pipe <NUM> connects the four-way switching valve <NUM> and the gas-side shutoff valve <NUM>.

The compressor <NUM> is configured to suck a low-pressure refrigerant in the refrigeration cycle from the suction pipe <NUM>, compresses the refrigerant by means of a compression mechanism (not depicted), and discharge the compressed refrigerant to the discharge pipe <NUM>.

The four-way switching valve <NUM> is a mechanism configured to switch a refrigerant flow direction to change a state of the refrigerant circuit <NUM> between a cooling operation state and a heating operation state. While the refrigerant circuit <NUM> is in the cooling operation state, the outdoor heat exchanger <NUM> functions as a refrigerant radiator (condenser) and an indoor heat exchanger <NUM> functions as a refrigerant evaporator. While the refrigerant circuit <NUM> is in the heating operation state, the outdoor heat exchanger <NUM> functions as a refrigerant evaporator and the indoor heat exchanger <NUM> functions as a refrigerant condenser. When the four-way switching valve <NUM> brings the state of the refrigerant circuit <NUM> into the cooling operation state, the four-way switching valve <NUM> causes the suction pipe <NUM> to communicate with the second gas refrigerant pipe <NUM> and causes the discharge pipe <NUM> to communicate with the first gas refrigerant pipe <NUM> (see solid lines in the four-way switching valve <NUM> in <FIG>). When the four-way switching valve <NUM> brings the state of the refrigerant circuit <NUM> into the heating operation state, the four-way switching valve <NUM> causes the suction pipe <NUM> to communicate with the first gas refrigerant pipe <NUM> and causes the discharge pipe <NUM> to communicate with the second gas refrigerant pipe <NUM> (see broken lines in the four-way switching valve <NUM> in <FIG>).

The outdoor heat exchanger <NUM> (exemplifying a heat exchanger) is configured to cause heat exchange between a refrigerant flowing inside and air (heat source air) at an installation site of the outdoor unit <NUM>. The outdoor heat exchanger <NUM> will be described in detail later.

The expansion mechanism <NUM> is disposed between the outdoor heat exchanger <NUM> and the indoor heat exchanger <NUM> on the refrigerant circuit <NUM>. The expansion mechanism <NUM> according to the present embodiment is disposed on the liquid refrigerant pipe <NUM> between the outdoor heat exchanger <NUM> and the liquid-side shutoff valve <NUM>. The expansion mechanism <NUM> is provided at the outdoor unit <NUM> in the air conditioner <NUM> according to the present embodiment. The expansion mechanism <NUM> may alternatively be provided at the indoor unit <NUM> to be described later. The expansion mechanism <NUM> is configured to adjust pressure and a flow rate of a refrigerant flowing in the liquid refrigerant pipe <NUM>. The expansion mechanism <NUM> according to the present embodiment is an electronic expansion valve having a variable opening degree. Alternatively, the expansion mechanism <NUM> may be a temperature sensitive cylinder expansion valve or a capillary tube.

The accumulator <NUM> is a vessel having a gas-liquid separation function of separating a received refrigerant into a gas refrigerant and a liquid refrigerant. The accumulator <NUM> is also a vessel having a function of reserving an excessive refrigerant generated due to operation load change or the like.

The liquid-side shutoff valve <NUM> is provided at a connecting portion between the liquid refrigerant pipe <NUM> and the liquid-refrigerant connection pipe <NUM>. The gas-side shutoff valve <NUM> is provided at a connecting portion between the second gas refrigerant pipe <NUM> and the gas-refrigerant connection pipe <NUM>. The liquid-side shutoff valve <NUM> and the gas-side shutoff valve <NUM> are opened while the air conditioner <NUM> is in operation.

The outdoor fan <NUM> is configured to suck outside heat source air into a casing (not depicted) of the outdoor unit <NUM> and supply the outdoor heat exchanger <NUM> with the heat source air, and to discharge air having exchanged heat with a refrigerant in the outdoor heat exchanger <NUM> from the casing of the outdoor unit <NUM>. Examples of the outdoor fan <NUM> include a propeller fan.

The indoor unit <NUM> is disposed in the air conditioning target space. The indoor unit <NUM> is, for example, of a ceiling embedded type. Alternatively, the indoor unit may be of a ceiling pendant type, a wall mounted type, or a floor-standing type. The indoor unit <NUM> may alternatively be disposed outside the air conditioning target space. For example, the indoor unit <NUM> may be installed in an attic space, a machine chamber, or a garage. In such a case, there is disposed an air passage for supply, from the indoor unit <NUM> to the air conditioning target space, of air having exchanged heat with a refrigerant in the indoor heat exchanger <NUM>. Examples of the air passage include a duct.

The indoor unit <NUM> principally includes the indoor heat exchanger <NUM> and an indoor fan <NUM> (see <FIG>).

The indoor heat exchanger <NUM> causes heat exchange between a refrigerant flowing in the indoor heat exchanger <NUM> and air in the air conditioning target space. The indoor heat exchanger <NUM> should not be limited in terms of its type, and is exemplarily a fin-and-tube heat exchanger including a plurality of heat transfer tubes and a plurality of fins (not depicted). The indoor heat exchanger <NUM> has a first end connected to the liquid-refrigerant connection pipe <NUM> via a refrigerant pipe. The indoor heat exchanger <NUM> has a second end connected to the gas-refrigerant connection pipe <NUM> via a refrigerant pipe.

The indoor fan <NUM> is a mechanism configured to suck air in the air conditioning target space into a casing (not depicted) of the indoor unit <NUM> and supply the indoor heat exchanger <NUM> with the air, and to blow, into the air conditioning target space, air having exchanged heat with a refrigerant in the indoor heat exchanger <NUM>. Examples of the indoor fan <NUM> include a turbo fan. The indoor fan <NUM> should not be limited to the turbo fan but may be appropriately selected in terms of its type.

The control unit <NUM> is a functional unit configured to control operation of various devices constituting the air conditioner <NUM>.

The control unit <NUM> is exemplarily constituted such that an outdoor control unit (not depicted) of the outdoor unit <NUM> and an indoor control unit (not depicted) of the indoor unit <NUM> are communicably connected via a transmission line (not depicted). Each of the outdoor control unit and the indoor control unit exemplarily includes a microcomputer, and a memory or the like storing various programs for control of the air conditioner <NUM> and executed by the microcomputer. <FIG> depicts, for convenience, the control unit <NUM> distant from the outdoor unit <NUM> and the indoor unit <NUM>.

The control unit <NUM> has a function that does not need to be implemented by cooperation of the outdoor control unit and the indoor control unit. For example, the function of the control unit <NUM> may be implemented by one of the outdoor control unit and the indoor control unit, or may be implemented partially or entirely by a control device (not depicted) different from the outdoor control unit and the indoor control unit.

As depicted in <FIG>, the control unit <NUM> is electrically connected to various devices of the outdoor unit <NUM> and the indoor unit <NUM>, including the compressor <NUM>, the four-way switching valve <NUM>, the expansion mechanism <NUM>, the outdoor fan <NUM>, and the indoor fan <NUM>. The control unit <NUM> is also electrically connected to various sensors (not depicted) provided at the outdoor unit <NUM> and the indoor unit <NUM>. The control unit <NUM> is configured to be communicable with a remote controller (not depicted) that is operated by a user of the air conditioner <NUM>.

The control unit <NUM> operates and stops the air conditioner <NUM>, and controls operation of the various devices constituting the air conditioner <NUM>, in accordance with measurement signals from the various sensors, a command received from the remote controller (not depicted), and the like.

The outdoor heat exchanger <NUM> will be described in terms of its configuration with reference to the drawings.

<FIG> is a schematic perspective view of the outdoor heat exchanger <NUM>. <FIG> is a partial enlarged view of a heat exchange unit <NUM> to be described later, in the outdoor heat exchanger <NUM>. <FIG> is a schematic view depicting attachment states of fins <NUM> to be described later, to flat tubes <NUM> in the heat exchange unit <NUM>. <FIG> is a schematic configuration diagram of the outdoor heat exchanger <NUM>. <FIG> includes arrows in the heat exchange unit <NUM>, indicating refrigerant flows during heating operation (when the outdoor heat exchanger <NUM> functions as an evaporator).

The following description may include expressions such as "up", "down", "left", "right", "front (before)", and "rear (behind)", for indication of directions and positions. These expressions follow directions of arrows included in <FIG>, unless otherwise specified. These expressions describing the directions and the positions are adopted for convenience of description. Unless otherwise specified, such expressions will not limit directions and positions of the entire outdoor heat exchanger <NUM> and various constituents of the outdoor heat exchanger <NUM> to the directions and the positions being described.

The outdoor heat exchanger <NUM> is configured to cause heat exchange between a refrigerant flowing inside and air.

The outdoor heat exchanger <NUM> principally includes a flow divider <NUM>, a flat tube group <NUM> including a plurality of flat tubes <NUM>, a plurality of fins <NUM>, and a liquid header <NUM> and a gas header <NUM> (exemplifying headers) (see <FIG> and <FIG>). Each one of the flow divider <NUM>, the flat tubes <NUM>, the fins <NUM>, the liquid header <NUM>, and the gas header <NUM> is made of aluminum or an aluminum alloy.

As to be described later, the flat tubes <NUM> and the fins <NUM> fixing the flat tubes <NUM> constitute the heat exchange unit <NUM> (see <FIG> and <FIG>). The outdoor heat exchanger <NUM> includes rather the heat exchange unit <NUM> in a single row than the plurality of flat tubes <NUM> aligned in an air flow direction. When air flows in air ducts constituted by the flat tubes <NUM> and the fins <NUM> of the heat exchange unit <NUM>, the outdoor heat exchanger <NUM> causes heat exchange between a refrigerant flowing in the flat tubes <NUM> and the air flowing in the air ducts. The heat exchange unit <NUM> is divided into a first heat exchange portion 27a, a second heat exchange portion 27b, a third heat exchange portion 27c, a fourth heat exchange portion 27d, and a fifth heat exchange portion 27e, which are aligned vertically (see <FIG>).

The flow divider <NUM> is a mechanism configured to distribute a refrigerant. The flow divider <NUM> is also a mechanism configured to merge refrigerants. The flow divider <NUM> is connected with the liquid refrigerant pipe <NUM>. The flow divider <NUM> includes a plurality of branching pipes 22a to 22e. The flow divider <NUM> has a function of distributing, into the plurality of branching pipes 22a to 22e, a refrigerant flowing into the flow divider <NUM> from the liquid refrigerant pipe <NUM>, and guiding the refrigerant into a plurality of spaces provided in the liquid header <NUM>. The flow divider <NUM> further has a function of merging refrigerants flowing from the liquid header <NUM> through the branching pipes 22a to 22e and guiding the refrigerants to the liquid refrigerant pipe <NUM>.

The flat tube group <NUM> exemplifies a heat transfer tube group. The flat tube group <NUM> includes, as a plurality of heat transfer tubes, the plurality of flat tubes <NUM> (exemplifying heat transfer tubes). As depicted in <FIG>, the flat tubes <NUM> are flat heat transfer tubes each having upper and lower flat surfaces 28a functioning as heat transfer surfaces. As in <FIG>, each of the flat tubes <NUM> is provided with a plurality of refrigerant passages 28b allowing refrigerants to flow. Examples of the flat tubes <NUM> include a flat porous tube provided with a large number of refrigerant passages 28b each having a small sectional area of a passage allowing a refrigerant to flow. The plurality of refrigerant passages 28b according to the present embodiment are aligned in the air flow direction. The flat tube <NUM> has a section vertical to the refrigerant passages 28b and having a maximum width that may be <NUM>% or more, or <NUM>% or more, of an outer diameter of a main gas refrigerant pipe connecting portion 19a.

As depicted in <FIG>, the outdoor heat exchanger <NUM> includes the flat tubes <NUM> that extend horizontally between the liquid header <NUM> and the gas header <NUM> and are aligned vertically to form a plurality of columns. In the present embodiment, each of the flat tubes <NUM> extending between the liquid header <NUM> and the gas header <NUM> is bent at two portions, such that the heat exchange unit <NUM> constituted by the flat tubes <NUM> has a substantially U shape in a planar view (see <FIG>). The flat tubes <NUM> extend in an anteroposterior direction (exemplifying a first direction) at portions connected to the gas header <NUM>, and extend in the anteroposterior direction at portions connected to the liquid header <NUM>. The plurality of flat tubes <NUM> according to the present embodiment is disposed to be constantly spaced apart in the vertical direction.

The plurality of fins <NUM> are members provided for increasing a heat transfer area of the outdoor heat exchanger <NUM>. The fins <NUM> are plate-shaped member extending along the columns of the flat tubes <NUM>. The outdoor heat exchanger <NUM> is used in a state where the plurality of flat tubes <NUM> extending horizontally is aligned vertically. The fins <NUM> extend vertically in a state where the outdoor heat exchanger <NUM> is installed in the outdoor unit <NUM>.

The fins <NUM> are provided with a plurality of cut-away parts 29a extending in a direction of inserting the flat tubes <NUM> as depicted in <FIG>, to receive the plurality of flat tubes <NUM>. The cut-away parts 29a extend in an extending direction of the fins <NUM>, and in a direction perpendicular to a thickness direction of the fins <NUM>. The cut-away parts 29a provided at the fins <NUM> extend horizontally in the state where the outdoor heat exchanger <NUM> is installed in the outdoor unit <NUM>. The cut-away parts 29a of the fins <NUM> substantially match an outline of the section of the flat tube <NUM>. The cut-away parts 29a are provided at the fins <NUM> so as to be spaced apart correspondingly to spaces of the aligned flat tubes <NUM>. In the outdoor heat exchanger <NUM>, the plurality of fins <NUM> is aligned in an extending direction of the flat tubes <NUM>. When the flat tubes <NUM> are inserted correspondingly to the plurality of 29a of the plurality of fins <NUM>, spaces between the flat tubes <NUM> adjacent to each other are divided into a plurality of air ducts allowing air to flow.

The fins <NUM> have connective portions 29b connected vertically and positioned upstream or downstream of the flat tubes <NUM> in the air flow direction. The connective portions 29b of the fins <NUM> are positioned upstream of the flat tubes <NUM> in the present embodiment.

The liquid header <NUM> and the gas header <NUM> are hollow members.

As depicted in <FIG>, the liquid header <NUM> is connected with first ends of the flat tubes <NUM>, and the gas header <NUM> is connected with second ends of the flat tubes <NUM>. The outdoor heat exchanger <NUM> is disposed in the casing (not depicted) of the outdoor unit <NUM> such that the liquid header <NUM> and the gas header <NUM> having substantially columnar shapes have axial directions substantially matching the vertical direction. The heat exchange unit <NUM> of the outdoor heat exchanger <NUM> according to the present embodiment has the U shape in a planar view as depicted in <FIG>. The liquid header <NUM> is disposed adjacent to a front left corner of the casing (not depicted) of the outdoor unit <NUM> (see <FIG>). The gas header <NUM> is disposed adjacent to a front right corner of the casing (not depicted) of the outdoor unit <NUM> (see <FIG>).

The liquid header <NUM> has a longitudinal direction matching the vertical direction.

The liquid header <NUM> has a liquid side internal space <NUM> divided into a plurality of sub spaces 23a to 23e by a plurality of partition plates <NUM> (see <FIG>).

The plurality of sub spaces 23a to 23e is aligned vertically. The sub spaces 23a to 23e are partitioned by the partition plates <NUM> so as not to be communicable with each other in the liquid side internal space <NUM> of the liquid header <NUM>.

The sub spaces 23a to 23e are connected, one by one, with the branching pipes 22a to 22e included in the flow divider <NUM>. During cooling operation, refrigerants reaching the sub spaces 23a to 23e flow in the branching pipes 22a to 22e to be merged at the flow divider <NUM>. During heating operation, refrigerants divided by the flow divider <NUM> are supplied to the sub spaces 23a to 23e.

The gas header <NUM> has a longitudinal direction matching the vertical direction (exemplifying a second direction).

The gas header <NUM> has a single internal space. The gas header <NUM> has a gas side internal space <NUM> provided with no partition plates partitioning vertically aligned spaces as in the liquid header <NUM>.

The gas header <NUM> is connected with the main gas refrigerant pipe connecting portion 19a and a branch gas refrigerant pipe connecting portion 19b constituting ends adjacent to the gas header <NUM>, of the first gas refrigerant pipe <NUM> (see <FIG>). Though not limited, the outer diameter of the main gas refrigerant pipe connecting portion 19a may be, for example, three times or more or five times or more, of an outer diameter of the branch gas refrigerant pipe connecting portion 19b.

The main gas refrigerant pipe connecting portion 19a has a first end connected to the gas header <NUM> so as to communicate with the gas side internal space <NUM> at an intermediate position in a height direction of the gas header <NUM>.

The branch gas refrigerant pipe connecting portion 19b has a first end connected to the gas header <NUM> so as to communicate with the gas side internal space <NUM> at a position adjacent to a lower end in the height direction of the gas header <NUM>. The branch gas refrigerant pipe connecting portion 19b has a second end connected to the main gas refrigerant pipe connecting portion 19a. The branch gas refrigerant pipe connecting portion 19b is smaller in inner diameter than the main gas refrigerant pipe connecting portion 19a and connected to the gas header <NUM> below the main gas refrigerant pipe connecting portion 19a, to allow refrigerating machine oil reserved adjacent to the lower end of the gas header <NUM> to flow into the main gas refrigerant pipe connecting portion 19a and return to the compressor <NUM>.

When the air conditioner <NUM> executes heating operation and the outdoor heat exchanger <NUM> functions as a refrigerant evaporator, a refrigerant in a gas-liquid two-phase state flowing from the liquid refrigerant pipe <NUM> and reaching the flow divider <NUM> flows through the branching pipes 22a to 22e and flows into the sub spaces 23a to 23e constituting the liquid side internal space <NUM> of the liquid header <NUM>. Specifically, the refrigerant flowing in the branching pipe 22a flows into the sub space 23a, the refrigerant flowing in the branching pipe 22b flows into the sub space 23b, the refrigerant flowing in the branching pipe 22c flows into the sub space 23c, the refrigerant flowing in the branching pipe 22d flows into the sub space 23d, and the refrigerant flowing in the branching pipe 22e flows into the sub space 23e, respectively. The refrigerants flowing into the sub spaces 23a to 23e of the liquid side internal space <NUM> flow in the flat tubes <NUM> connected to the sub spaces 23a to 23e. The refrigerants flowing in the flat tubes <NUM> exchange heat with air to be evaporated and become gas-phase refrigerants, and flow into the gas side internal space <NUM> of the gas header <NUM> to be merged.

When the air conditioner <NUM> executes cooling operation or frost operation, the refrigerant flows in the refrigerant circuit <NUM> oppositely to the case of heating operation. Specifically, a gas-phase refrigerant having high temperature flows into the gas side internal space <NUM> of the gas header <NUM> through the main gas refrigerant pipe connecting portion 19a and the branch gas refrigerant pipe connecting portion 19b of the first gas refrigerant pipe <NUM>. The refrigerant flowing into the gas side internal space <NUM> of the gas header <NUM> are distributed to flow into the flat tubes <NUM>. Refrigerants flowing into the flat tubes <NUM> passes through the flat tubes <NUM> and flows into the sub spaces 23a to 23e of the liquid side internal space <NUM> of the liquid header <NUM>. The refrigerants flowing into the sub spaces 23a to 23e of the liquid side internal space <NUM> are merged by the flow divider <NUM> to be flow out to the liquid refrigerant pipe <NUM>.

<FIG> is an outer appearance configuration diagram in a side view, depicting how the main gas refrigerant pipe connecting portion 19a is connected to the gas header <NUM>. <FIG> is a planar sectional view of the gas header <NUM>. <FIG> is a planar sectional view depicting how the main gas refrigerant pipe connecting portion 19a and the flat tube <NUM> are connected to the gas header <NUM>.

<FIG> is a schematic view from behind, of a first member <NUM>. <FIG> is a schematic view from behind, of a third member <NUM>. <FIG> is a schematic view from behind, of a second member <NUM>. <FIG> is a schematic view from behind, of a fourth member <NUM>. <FIG> is a projection view depicting positional relationship of openings in a case where the first member <NUM> is viewed from behind.

<FIG> is a planar sectional view of clad layers in the first member <NUM>, the third member, and the fourth member constituting the gas header <NUM>.

The gas header <NUM> includes the first member <NUM>, the second member <NUM>, the third member <NUM>, the fourth member <NUM>, as well as a top lid member and a bottom lid member (not depicted). The gas header <NUM> is constituted such that the first member <NUM>, the second member <NUM>, the third member <NUM>, the fourth member <NUM>, the top lid member, and the bottom lid member are joined by brazing.

The gas header <NUM> has an outline in a planar view, which has a substantially quadrilateral shape provided with one side connected with the flat tubes <NUM>.

The first member <NUM> principally constitutes a periphery of the outline of the gas header <NUM>, along with the fourth member <NUM> to be described later.

The first member <NUM> has a clad layer C1 containing a brazing filler material and provided on a surface (outer surface) constituting a circumference of the gas header <NUM>, of a core material made of aluminum or an aluminum alloy. The first member <NUM> has a clad layer C2 (exemplifying a brazing layer between the first member and the second member, or exemplifying a brazing layer between the first member and the third member) containing a brazing filler material and provided on a surface (inner surface) opposite to the surface constituting the circumference of the gas header <NUM>, of the core material made of aluminum or an aluminum alloy. Though not limited, an exemplary member (the same applies hereinafter) provided with a clad layer may be manufactured while joining a plate-shaped clad layer to a core material by means of hot rolling. The first member <NUM> according to the present embodiment can be formed through bending, at a pleat line in a longitudinal direction of the gas header <NUM>, a single sheet metal obtained by rolling or the like. In this case, the first member <NUM> has a first thickness that is uniform across portions. The first thickness is preferably less than the maximum thickness of the second member <NUM> or a thickness of the fourth member <NUM>, and may be equal in thickness to the third member <NUM>. The first thickness can be exemplarily set to <NUM> or more and <NUM> or less, and is preferably <NUM>.

The clad layer C1 constitutes the outer surface of the gas header <NUM>, and thus contains the brazing filler material as well as a sacrificial anodic material having corrosion resistance. Examples of the sacrificial anodic material include zinc or an alloy containing zinc. The clad layer C1 contains silicon having a content that can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. The clad layer C1 contains an Al-Si alloy having a content that can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. Examples of the clad layer C1 include an alloy having A4N43 as an alloy number prescribed by the Japanese Industrial Standards for aluminum.

The clad layer C2 constitutes the inner surface of the gas header <NUM>, and thus needs no corrosion resistance. The clad layer C2 contains silicon having a content that may be equal to or different from the content of the clad layer C1, and can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. The clad layer C2 contains an Al-Si alloy having a content that can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. Examples of the clad layer C2 include an alloy having A4343 as an alloy number prescribed by the Japanese Industrial Standards for aluminum.

The first member <NUM> includes a flat tube connection plate 71a, a first outer wall 71b, a second outer wall 71c, a first claw 71d, and a second claw 71e.

The flat tube connection plate 71a (exemplifying a first portion) is a flat plate portion expanding vertically and transversely. The flat tube connection plate 71a is provided with a plurality of flat tube connection openings 71x (exemplifying openings) aligned vertically. The flat tube connection openings 71x penetrate the flat tube connection plate 71a in its thickness direction. In a state where the flat tubes <NUM> are inserted to the flat tube connection openings 71x such that first ends of the flat tubes <NUM> completely pass therethrough, the flat tubes <NUM> are joined by brazing. In such a state where the flat tubes <NUM> are joined by brazing, an entire inner circumferential surface of each of the flat tube connection openings 71x is in contact with an entire outer circumferential surface of a corresponding one of the flat tubes <NUM>. The first thickness of the first member <NUM> including the flat tube connection plate 71a is set relatively small such as about <NUM> or more and <NUM> or less, and the inner circumferential surfaces of the flat tube connection openings 71x can thus have small length in a thickness direction. When the flat tubes <NUM> are inserted to the flat tube connection openings 71x prior to joining by brazing, the inner circumferential surface of each of the flat tube connection openings 71x and the outer circumferential surface of the corresponding one of the flat tubes <NUM> generate less friction for facilitated insertion.

The first outer wall 71b is a planar portion extending forward from a front surface of a left (inside the outdoor unit <NUM> and the liquid header <NUM> side) end of the flat tube connection plate 71a along a first inner wall 72b to be described later.

The second outer wall 71c is a planar portion extending forward from a front surface of a right (outside the outdoor unit <NUM> and far from the liquid header <NUM>) end of the flat tube connection plate 71a along a second inner wall 72c to be described later.

The first claw 71d extends rightward from a front end of the first outer wall 71b. The second claw 71e extends leftward from a front end of the second outer wall 71c.

The first claw 71d and the second claw 71e extend along and beyond the first outer wall 71b and the second outer wall 71c, respectively, before the second member <NUM>, the third member <NUM>, and the fourth member <NUM> are disposed inside the first member <NUM> in a planar view. In a state where the second member <NUM>, the third member <NUM>, and the fourth member <NUM> are disposed inside the first member <NUM> in a planar view, the first claw 71d and the second claw 71e are bent to be closer to each other such that the first member <NUM> caulks the second member <NUM>, the third member <NUM>, and the fourth member <NUM> so as to be fixed to each other. Brazing is executed in a furnace or the like in this state to join the members by brazing for complete fixation.

The third member <NUM> is a flat plate portion laminated to be in contact with a surface connected with the first gas refrigerant pipe <NUM>, of the flat tube connection plate 71a of the first member <NUM> and expanding vertically and transversely. The third member <NUM> is similar in transverse length to a portion excluding the both ends of the flat tube connection plate 71a of the first member <NUM>.

The third member <NUM> does not include any portion constituting the circumference of the gas header <NUM>, but constitutes an internal portion of the gas header <NUM> and is positioned inside the first member <NUM>.

The third member <NUM> has a clad layer C3 (exemplifying a brazing layer between the second member and the third member) containing a brazing filler material and provided on a surface (the second member <NUM> side surface) opposite to a surface facing the flat tube connection plate 71a of the first member <NUM>, of a core material made of aluminum or an aluminum alloy.

The third member <NUM> has uniform third thickness. The third thickness is preferably less than the maximum thickness of the second member <NUM> or the thickness of the fourth member <NUM>, and may be equal in thickness to the first member <NUM>. The third thickness can be exemplarily se to <NUM> or more and <NUM> or less, and is preferably <NUM>.

The clad layer C3 contains silicon having a content that can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. The clad layer C3 contains an Al-Si alloy having a content that can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. Examples of the clad layer C3 include an alloy having A4045 as an alloy number prescribed by the Japanese Industrial Standards for aluminum.

Though not limited, the third member <NUM> may not be provided with any clad layer on the surface opposite to the surface provided with the clad layer C3, and may be preferably provided with a flux layer for removal of a surface oxide film.

The third member <NUM> includes an inner plate 73a and a plurality of internal openings 73x.

The inner plate 73a has a flat plate shape expanding vertically and transversely.

The plurality of internal openings 73x (exemplifying second openings) is aligned vertically and penetrates the inner plate 73a in its thickness direction.

The internal openings 73x of the third member <NUM> are larger than the flat tube connection openings 71x provided in the flat tube connection plate 71a of the first member <NUM>. In the state where the third member <NUM> is laminated on the flat tube connection plate 71a of the first member <NUM>, the internal openings 73x in the third member <NUM> have outer edges positioned outside outer edges of the flat tube connection openings 71x provided in the flat tube connection plate 71a of the first member <NUM> in a lamination direction of members, more specifically, in the anteroposterior direction. This configuration inhibits the brazing filler material from shifting due to a capillary phenomenon during joining by brazing and blocking the refrigerant passages 28b of each of the flat tubes <NUM>. In view of this, the outer edges of the internal openings 73x of the third member <NUM> have upper and lower portions that may be distant by <NUM> or more from upper and lower portions of the outer edges of the flat tube connection openings 71x of the flat tube connection plate 71a, and are preferably distant by <NUM> or more.

The clad layer C3 of the third member <NUM> is positioned inside the clad layer C2 of the first member <NUM> in the gas header <NUM>.

The second member <NUM> is disposed between the flat tube connection plate 71a of the first member <NUM> and the main gas refrigerant pipe connecting portion 19a in the anteroposterior direction. The second member <NUM> has a substantially U shape in a planar view.

Inside the second member <NUM>, more specifically, in a space surrounded with the second member <NUM>, the third member <NUM>, and the ends of the flat tubes <NUM>, the gas side internal space <NUM> is provided.

The maximum thickness of the second member <NUM> is preferably more than the thickness of the first member <NUM>. The maximum thickness of the second member <NUM> may be preferably <NUM> or less and may be more preferably <NUM> in view of facilitated pressing and punching.

Though not limited, the second member <NUM> is preferably obtained through extrusion molding in an extrusion direction matching the longitudinal direction of the gas header <NUM>. Extrusion molding facilitates provision of portions varied in thickness. A thick sheet metal is relatively expensive. Provision of the thick second member <NUM> through extrusion direction leads to cost reduction. The second member <NUM> according to the present embodiment, which is obtained through extrusion direction, is not provided with any clad layer containing a brazing filler material.

The second member <NUM> includes the first inner wall 72b, the second inner wall 72c, a coupling portion 72a, a first projection 72d, a second projection 72e, a first edge 72f, and a second edge <NUM>.

The coupling portion 72a is a plate-shaped portion facing a main gas refrigerant pipe connecting portion 19a side surface, of the third member <NUM>, and expanding vertically and transversely. The coupling portion 72a is positioned in the main gas refrigerant pipe connecting portion 19a side of the gas header <NUM>. The coupling portion 72a is provided with an internal gas pipe connection opening 72x connected with an end of the main gas refrigerant pipe connecting portion 19a and penetrating the coupling portion 72a in its thickness direction. The coupling portion 72a is further provided with an opening (not depicted) connected with an end of the branch gas refrigerant pipe connecting portion 19b and penetrating the coupling portion 72a in the thickness direction.

The first inner wall 72b is a planar portion extending backward toward the extending flat tubes <NUM>, from a left (inside the outdoor unit <NUM> and the liquid header <NUM> side) end of the coupling portion 72a. The first inner wall 72b has a left surface in surface contact with a right surface of the first outer wall 71b of the first member <NUM>.

The second inner wall 72c is a planar portion extending backward toward the extending flat tubes <NUM>, from a right (outside the outdoor unit <NUM> and far from the liquid header <NUM>) end of the coupling portion 72a. The second inner wall 72c has a right surface in surface contact with a left surface of the second outer wall 71c of the first member <NUM>.

The first inner wall 72b and the second inner wall 72c face each other. Specifically, a front end of the first inner wall 72b and a front end of the second inner wall 72c also face each other.

The coupling portion 72a, the first inner wall 72b, and the second inner wall 72c are thicker than the first member <NUM>, and may be thicker by <NUM> times or more and are preferably thicker by <NUM> times or more.

Though not limited, the first inner wall 72b and the second inner wall 72c have length in an extending direction (anteroposterior direction) of the flat tubes <NUM>, which may be larger by three times or more and is preferably larger by five times or more than length of the coupling portion 72a in the extending direction (anteroposterior direction) of the flat tubes <NUM>.

The coupling portion 72a couples the first inner wall 72b and the second inner wall 72c. Specifically, the coupling portion 72a couples the front end (the main gas refrigerant pipe connecting portion 19a side end) of the first inner wall 72b and the front end (the main gas refrigerant pipe connecting portion 19a side end) of the second inner wall 72c. The coupling portion 72a extends transversely (exemplifying a third direction that is preferably perpendicular to both the first direction and the second direction, and the first direction, the second direction, and the third direction are more preferably perpendicular to one another) in a planar view of the gas header <NUM>.

The second member <NUM> can increase the gas side internal space <NUM> by simply extending the first inner wall 72b and the second inner wall 72c without adding any other member. This configuration allows a gas refrigerant to be unlikely to have pressure loss while passing through the gas side internal space <NUM>. Although the first inner wall 72b and the second inner wall 72c extend in the extending direction of the flat tubes <NUM> for increasing the gas side internal space <NUM>, the first inner wall 72b and the second inner wall 72c are coupled via the coupling portion 72a to integrate the coupling portion 72a, the first inner wall 72b, and the second inner wall 72c. This configuration can improve strength of the second member <NUM> and improve compressive strength of the gas header <NUM>.

The first edge 72f is provided behind (the flat tubes <NUM> side) the first inner wall 72b. The first edge 72f has a left surface provided flush with the left surface of the first inner wall 72b, and is in surface contact with the right surface of the first outer wall 71b of the first member <NUM>. The first edge 72f has a rear end in contact with a front surface of the third member <NUM>. The first edge 72f has a thickness (transverse width) less than thickness (transverse width) of the first inner wall 72b. The first edge 72f and the front surface of the third member <NUM> are in contact with each other at a position displaced leftward from the flat tubes <NUM> and displaced leftward from left ends of the internal openings 73x of the third member <NUM>.

The second edge <NUM> is provided behind (the flat tubes <NUM> side) the second inner wall 72c. The second edge <NUM> has a right surface provided flush with the right surface of the second inner wall 72c, and is in surface contact with the left surface of the second outer wall 71c of the first member <NUM>. The second edge <NUM> has a rear end in contact with the front surface of the third member <NUM>. The second edge <NUM> has a thickness (transverse width) less than a thickness (transverse width) of the second inner wall 72c. The second edge <NUM> and the front surface of the third member <NUM> are in contact with each other at a position displaced rightward from the flat tubes <NUM> and displaced rightward from right ends of the internal openings 73x of the third member <NUM>.

In a planar view, the first edge 72f and the second edge <NUM> are distant from each other by length that is larger than width of the flat tubes <NUM>, is larger than width of the flat tube connection openings 71x of the first member <NUM>, and is larger than width of the internal openings 73x of the third member <NUM>. Each of the first edge 72f and the second edge <NUM> extends from an upper end to a lower end of the gas header <NUM>.

The first projection 72d extends rightward (toward the second inner wall 72c) from a portion in front of the first edge 72f at a rear end of the first inner wall 72b. The first projection 72d extends from the upper end to the lower end of the gas header <NUM>. The first projection 72d has a right end displaced rightward from the left ends of the internal openings 73x of the third member <NUM> and displaced rightward from left ends of the flat tubes <NUM>. The first projection 72d is positioned closer to the flat tubes <NUM> than an anteroposterior center of the second member <NUM>.

The second projection 72e extends leftward (toward the first inner wall 72b) from a portion in front of the second edge <NUM> at a rear end of the second inner wall 72c. The second projection 72e extends from the upper end to the lower end of the gas header <NUM>. The second projection 72e has a left end displaced leftward from the right ends of the internal openings 73x of the third member <NUM> and displaced leftward from right ends of the flat tubes <NUM>. The second projection 72e is positioned closer to the flat tubes <NUM> than the anteroposterior center of the second member <NUM>.

The first projection 72d and the second projection 72e have a minimum distance (transverse distance) smaller than the maximum width on the section vertical to the refrigerant passages 28b of each of the flat tubes <NUM>. When the flat tubes <NUM> are inserted to the gas header <NUM>, the first projection 72d and the second projection 72e can thus set how deep the flat tubes <NUM> are inserted. This configuration inhibits reduction of the gas side internal space <NUM> due to excessive insertion of the flat tubes <NUM>. Furthermore, the first projection 72d and the second projection 72e can align the ends of the plurality of flat tubes <NUM> in the gas header <NUM>.

The fourth member <NUM> is a flat plate portion laminated to be in contact with a front surface of the coupling portion 72a of the second member <NUM> and expanding vertically and transversely. The fourth member <NUM> is similar in transverse length to the third member <NUM>, and is similar in transverse length to the portion excluding the both ends of the flat tube connection plate 71a of the first member <NUM>.

The fourth member <NUM> is provided with a clad layer C4 having a surface (outer surface) constituting the circumference of the gas header <NUM> and containing a brazing filler material. The fourth member <NUM> has a clad layer C5 containing a brazing filler material and provided on a surface (inner surface) opposite to a surface constituting the circumference of the gas header <NUM>, of a core material made of aluminum or an aluminum alloy.

The fourth member <NUM> has a uniform fourth thickness. The fourth thickness is preferably more than the first thickness and the third thickness, and may be equal in thickness to the first member <NUM>. The fourth thickness is preferably <NUM> or less in view of facilitated pressing and punching, is preferably <NUM> or more in view of improvement in compressive strength, and may be more preferably <NUM>.

The clad layer C4 constitutes the outer surface of the gas header <NUM>, and thus contains the brazing filler material as well as a sacrificial anodic material having corrosion resistance. Examples of the sacrificial anodic material include zinc or an alloy containing zinc. The clad layer C4 contains silicon having a content that can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. The clad layer C4 contains an Al-Si alloy having a content that can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. Examples of the clad layer C4 include an alloy having A4N43 as an alloy number prescribed by the Japanese Industrial Standards for aluminum.

The clad layer C5 constitutes the inner surface of the gas header <NUM>, and thus needs no corrosion resistance. The clad layer C5 contains silicon having a content that may be equal to or different from the content of the clad layer C4, and can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. The clad layer C5 contains an Al-Si alloy having a content that can be exemplarily set to <NUM> percent by weight or more and <NUM> percent by weight or less. Examples of the clad layer C5 include an alloy having A4343 as an alloy number prescribed by the Japanese Industrial Standards for aluminum.

The fourth member <NUM> is a plate-shaped member and can thus be easily provided on the surface with a clad layer containing a brazing filler material. Even in a case where the second member <NUM> is not provided with any clad layer containing a brazing filler material as in an exemplary case where the second member <NUM> is obtained through extrusion, the second member <NUM> can be joined by brazing to any other member with use of the brazing filler material provided on the fourth member <NUM>.

The fourth member <NUM> includes an outer plate 74a and an external gas pipe connection opening 74x.

The outer plate 74a has a flat plate shape expanding vertically and transversely.

The external gas pipe connection opening 74x is connected with the end of the main gas refrigerant pipe connecting portion 19a and penetrates the outer plate 74a in its thickness direction.

The outer plate 74a is further provided, in a lower portion, with an opening (not depicted) connected with the end of the branch gas refrigerant pipe connecting portion 19b and penetrating the outer plate 74a in the thickness direction.

The main gas refrigerant pipe connecting portion 19a and the branch gas refrigerant pipe connecting portion 19b thus communicate with an inner surface of the flat tube connection plate 71a of the first member <NUM> via the external gas pipe connection opening 74x, the internal gas pipe connection opening 72x, and the gas side internal space <NUM> interposed between the first inner wall 72b and the second inner wall 72c.

The fourth member <NUM> has a front surface caulked while being in contact with the first claw 71d and the second claw 71e of the first member <NUM>.

The outdoor heat exchanger <NUM> is heated in a furnace to be brazed in a state where the plurality of flat tubes <NUM>, the flow divider <NUM>, the first gas refrigerant pipe <NUM>, and the like are temporarily assembled to the liquid header <NUM> and the gas header <NUM>.

When the gas header <NUM> is temporarily assembled, a portion of the clad layer C2 provided on the flat tube connection plate 71a of the first member <NUM> is made in contact with a portion of the third member <NUM> where the clad layer C3 is not provided, and portions of the clad layer C2 provided inside the first outer wall 71b and the second outer wall 71c of the first member <NUM> are made in contact with the first inner wall 72b and the second inner wall 72c of the second member <NUM>. The clad layer C3 of the third member <NUM> is made in contact with rear surfaces of the first edge 72f and the second edge <NUM> of the second member <NUM>. The fourth member <NUM> has a portion provided with the clad layer C5, the portion being made in contact with the front surface of the coupling portion 72a of the second member <NUM>, and has both left and right ends of a portion provided with the clad layer C4, the ends being caulked by the first claw 71d and the second claw 71e to be made in contact with rear surfaces of the first claw 71d and the second claw 71e.

The outdoor heat exchanger <NUM> thus temporarily assembled is heated in a furnace to melt the clad layers C1 to C5 to braze the first member <NUM>, the second member <NUM>, the third member <NUM>, and the fourth member <NUM> each other. The outdoor heat exchanger <NUM> placed in a furnace has ambient temperature being exemplarily <NUM> or more and <NUM> or less.

(<NUM>-<NUM>)
In the gas header <NUM> of the outdoor heat exchanger <NUM> according to the present embodiment, the clad layer C3 on the third member <NUM> positioned inside the first member <NUM> is larger in silicon content than the clad layer C1 and the clad layer C2 on the first member <NUM> positioned at the circumference.

When the members constituting the gas header <NUM> are brazed in a furnace or the like, even if the third member <NUM> at an inner position is not higher in temperature than the first member <NUM> at an outer position, the brazing filler material contained in the clad layer C3 on the third member <NUM> can generate more melt in comparison to a case where the clad layer C3 on the third member <NUM> is equal in silicon content to the clad layer C1 and the clad layer C2 on the first member <NUM>.

This configuration achieves excellent joining by brazing of a member positioned inside the gas header <NUM>. This configuration also achieves an excellent joining state of brazing with use of a clad layer positioned inside the gas header <NUM>.

Specifically when the gas side internal space <NUM> of the gas header <NUM> is increased to have a larger capacity, a problem in which an inner member and an inner clad layer have more difficulty in receiving heat during heating for brazing becomes evident. Even in such a case, joining by brazing can be excellently achieved with an increase in a melt rate by increasing silicon content of the member and the inner clad layer that have more difficulty in receiving heat.

(<NUM>-<NUM>)
When the flat tubes which are flat heat transfer tubes are inserted to a conventional gas header having a cylindrical shape, the flat tubes need to be inserted deeply to the gas header such that the entire ends of the flat tubes are positioned inside the gas header having the cylindrical shape. In the gas header having the cylindrical shape, the ends of the flat tubes are accordingly provided thereabove and therebelow with useless spaces allowing a refrigerant to be reserved. Such a tendency is more significant as the flat tubes have larger width.

In contrast, in the gas header <NUM> of the outdoor heat exchanger <NUM> according to the present embodiment, the flat tube connection plate 71a of the first member <NUM> and the third member <NUM> have the plate shapes. Furthermore, the flat tubes <NUM> are inserted vertically to the flat tube connection plate 71a of the first member <NUM> and the third member <NUM>. The first outer wall 71b and the second outer wall 71c extend vertically from both the left and right ends of the flat tube connection plate 71a of the first member <NUM>, and the first inner wall 72b and the second inner wall 72c of the second member <NUM> are joined vertically to both the left and right ends of the third member <NUM>.

The gas header <NUM> of the outdoor heat exchanger <NUM> according to the present embodiment can thus decrease the useless spaces allowing a refrigerant to be reserved, around the ends of the flat tubes <NUM>. This achieves reduction in pressure loss of a gas refrigerant flowing in the gas header <NUM>.

(<NUM>-<NUM>)
In the gas header <NUM> of the outdoor heat exchanger <NUM> according to the present embodiment, the first member <NUM> including the flat tube connection plate 71a is relatively thinned. When the flat tubes <NUM> are inserted to the flat tube connection openings 71x prior to joining by brazing, the inner circumferential surface of each of the flat tube connection openings 71x and the outer circumferential surface of the corresponding one of the flat tubes <NUM> generate less friction for facilitated insertion.

Even when the first member <NUM> including the flat tube connection plate 71a is relatively thinned, the flat tube connection plate 71a further has the third member <NUM> laminated in the thickness direction. This configuration can thus improve compressive strength of the gas header <NUM> at the portion connected with the flat tubes <NUM>.

Furthermore, the outer edges of the internal openings 73x of the third member <NUM> are positioned outside the outer edges of the flat tube connection openings 71x provided in the flat tube connection plate 71a of the first member <NUM>. Even when the brazing filler material interposed between the flat tube connection openings 71x of the flat tube connection plate 71a and the flat tubes <NUM> leaks toward the ends of the flat tubes <NUM> during brazing, the brazing filler material having leaked is sent outside the flat tubes <NUM>, into spaces in the internal openings 73x of the third member <NUM>. This inhibits the refrigerant passages 28b of each of the flat tubes <NUM> from being filled with the brazing filler material.

(<NUM>-<NUM>)
In the gas header <NUM> of the outdoor heat exchanger <NUM> according to the present embodiment, the first projection 72d and the second projection 72e of the second member <NUM> have the minimum distance (transverse distance) smaller than the maximum width on the section vertical to the refrigerant passages 28b of each of the flat tubes <NUM>. This configuration can thus set how deep the flat tubes <NUM> are inserted to the gas header <NUM>.

The first projection 72d and the second projection 72e that define how deep the flat tubes <NUM> are inserted are both positioned closer to the flat tubes <NUM> than the anteroposterior center of the second member <NUM>. This makes it possible to sufficiently increase the gas side internal space <NUM>.

The embodiment described above exemplifies the case where the coupling portion 72a couples the end of the first inner wall 72b and the end of the second inner wall 72c in the second member <NUM> included in the gas header <NUM> of the outdoor heat exchanger <NUM>.

The second member included in the gas header <NUM> of the outdoor heat exchanger <NUM> may alternatively be replaced with a second member <NUM> depicted in <FIG> and <FIG>.

<FIG> is a planar sectional view depicting how the main gas refrigerant pipe connecting portion 19a and the flat tube <NUM> are connected to the gas header <NUM>. <FIG> is a projection view depicting positional relationship of openings in a case where the second member <NUM> is viewed from behind.

The second member <NUM> includes a coupling portion 172a in place of the coupling portion 72a of the second member <NUM> according to the above embodiment. The coupling portion 172a couples a portion between the both ends in the anteroposterior direction (the extending direction of the flat tubes <NUM>) of the first inner wall 72b and a portion between the both ends in the anteroposterior direction (the extending direction of the flat tubes <NUM>) of the second inner wall 72c. The coupling portion 172a couples the portions other than the ends, of the first inner wall 72b and the second inner wall 72c to achieve improvement in structural strength of the second member <NUM>.

The coupling portion 172a is a plate-shaped portion expanding vertically and transversely. The coupling portion 172a has a plurality of internal gas pipe connection openings 172x aligned vertically. The internal gas pipe connection openings 172x are provided correspondingly to the flat tubes <NUM>. The internal gas pipe connection openings 172x are larger in vertical size than the flat tubes <NUM> and the flat tube connection openings 71x of the first member <NUM>, but are smaller in size in a width direction (transverse direction) than the flat tubes <NUM> and the flat tube connection openings 71x of the first member <NUM>. This configuration can thus set how deep the flat tubes <NUM> are inserted. The internal gas pipe connection openings 172x have edges that can set how deep the flat tubes <NUM> are inserted, and there is thus no need to provide the first projection 72d or the second projection 72e of the second member <NUM> according to the above embodiment.

The above embodiment exemplifies the case where the gas header <NUM> includes the third member <NUM> and the fourth member <NUM>.

As exemplarily depicted in <FIG>, the gas header <NUM> may alternatively exclude at least one of the third member <NUM> and the fourth member <NUM> according to the above embodiment.

In this case, the flat tube connection plate 71a of the first member <NUM> is made thicker to secure compressive strength.

The above embodiment exemplifies the case where the clad layer C3 on the third member <NUM> positioned inside the gas header <NUM> is larger in silicon content than the clad layer C1 and the clad layer C2 on the first member <NUM> positioned outside the gas header <NUM>.

Alternatively, in an example not falling under the scope of the claims, at least one of the gas header and the liquid header in the heat exchanger may be replaced with, for example, a header <NUM> obtained through joining by brazing members as depicted in <FIG>.

The header <NUM> includes a first outer member <NUM>, a first inner member <NUM>, a second inner member <NUM>, a third inner member <NUM>, and a second outer member <NUM>.

All of the first outer member <NUM>, the first inner member <NUM>, the second inner member <NUM>, the third inner member <NUM>, and the second outer member <NUM> are plate-shaped members. The first outer member <NUM>, the first inner member <NUM>, the second inner member <NUM>, the third inner member <NUM>, and the second outer member <NUM> are aligned in the mentioned order and are joined to each other by brazing.

The first outer member <NUM> (exemplifying a first member or exemplifying a fifth member) has a plurality of heat transfer tube connection openings 271x connected with a plurality of heat transfer tubes such as the flat tubes <NUM> described in the above embodiment. The heat transfer tube connection openings 271x penetrate in the thickness direction. The plurality of heat transfer tube connection openings 271x is aligned in a longitudinal direction of the first outer member <NUM>.

The first inner member <NUM> (exemplifying a third member or exemplifying a seventh member) is joined by brazing to the first outer member <NUM>. The first inner member <NUM> has a first internal opening 272x to be communicable with the plurality of heat transfer tube connection openings 271x.

The second inner member <NUM> (exemplifying a second member or exemplifying a sixth member) has a first surface joined by brazing to the first inner member <NUM> and a second surface joined by brazing to the third inner member <NUM>. The second inner member <NUM> has a second internal opening 273x similar in size to the first internal opening 272x of the first inner member <NUM>.

The third inner member <NUM> (exemplifying the third member or exemplifying the seventh member) is joined by brazing to the second outer member <NUM>. The third inner member <NUM> has a third internal opening 274x similar in size to the second internal opening 273x of the second inner member <NUM>.

The second outer member <NUM> (exemplifying the first member or exemplifying the fifth member) has an external refrigerant pipe connection opening 275x connected with the main gas refrigerant pipe connecting portion 19a or the like described in the above embodiment or a refrigerant pipe as a liquid refrigerant pipe. The external refrigerant pipe connection opening 275x penetrates in the thickness direction. The external refrigerant pipe connection opening 275x communicates with the third internal opening 274x of the third inner member <NUM>.

In the configuration described above, a clad layer is provided on each surface of at least both surfaces of the first inner member <NUM> and both surfaces of the third inner member <NUM>. Specifically, a clad layer C6 (exemplifying a brazing layer between the first member and the second member, exemplifying a brazing layer between the first member and the third member, or exemplifying a first clad layer) is provided on the first outer member <NUM> side surface of the first inner member <NUM>. A clad layer C7 (exemplifying a brazing layer between the second member and the third member, or exemplifying a second clad layer) is provided on the second inner member <NUM> side surface of the first inner member <NUM>. A clad layer C8 (exemplifying the brazing layer between the first member and the second member, exemplifying the brazing layer between the first member and the third member, or exemplifying the first clad layer) is provided on the second outer member <NUM> side surface of the third inner member <NUM>. A clad layer C9 (exemplifying the brazing layer between the second member and the third member, or exemplifying the second clad layer) is provided on the second inner member <NUM> side surface of the third inner member <NUM>.

Each of the clad layers C6 to C9 contains silicon, and contains an Al-Si alloy or the like. The clad layer C7 is larger in silicon content than the clad layer C6. The clad layer C9 is larger in silicon content than the clad layer C8.

In the configuration described above, it is difficult for the second inner member <NUM> to receive heat in a case of joining by brazing while the first outer member <NUM>, the first inner member <NUM>, the second inner member <NUM>, the third inner member <NUM>, and the second outer member <NUM> are laminated and a heat source is disposed at least one of the first outer member <NUM> side and the second outer member <NUM> side. However, the clad layer C7 is larger in silicon content than the clad layer C6 and the clad layer C9 is larger in silicon content than the clad layer C8. Thus, the clad layer C7 and the clad layer C9 far from the heat source can also achieve an increase in a melt rate for excellent joining by brazing.

The above embodiment and the modification examples exemplify the case where, in two clad layers joining members, the clad layer far from the heat source is larger in silicon content than the clad layer close to the heat source to achieve an increase in a melt rate for excellent joining by brazing.

Alternatively, there may be provided three or more clad layers joining members varied in distance from the heat source and the clad layers are aligned such that a clad layer further from the heat source has a larger silicon content, to achieve an increase in the melt rate for excellent joining by brazing.

Claim 1:
A heat exchanger (<NUM>) comprising a header (<NUM>, <NUM>) and a plurality of heat transfer tubes (<NUM>) connected to the header, wherein
the header has a plurality of members including a first member (<NUM>, <NUM>, <NUM>), a second member (<NUM>, <NUM>), and a third member (<NUM>, <NUM>, <NUM>) which are brazed,
wherein
the first member has a first portion (71a), the first portion having a plate shape and a plurality of first openings (71x) into which the heat transfer tubes are inserted,
the third member is a plate-shaped member having a plurality of second openings (73x) into which the heat transfer tubes are inserted,
the first portion and the third member are laminated in a thickness direction,
in a view along an extending direction of the heat transfer tubes, each of the first openings has an outline positioned inside an outline of a corresponding one of the second openings, and characterised in that a brazing layer (C3, C7, C9) between the second member and the third member has a melt rate, at a predetermined temperature, being larger than a melt rate, at the predetermined temperature, of at least one of a brazing layer (C2, C6, C8) between the first member and the second member and a brazing layer (C2) between the first member and the third member, wherein
the brazing layer (C3) between the second member and the third member is disposed inside a space defined by the brazing layer (C2) between the first member and the second member and the brazing layer (C2) between the first member and the third member, and in that
the brazing layer (C3, C7, C9) between the second member and the third member has a silicon content larger than a silicon content of at least one of a brazing layer (C2, C6, C8) between the first member and the second member and a brazing layer (C2) between the first member and the third member.