Patent Description:
Hitherto, a refrigerant cycle device, such as an air conditioner, has used a heat exchanger constituted by connecting heat transfer tubes in which a refrigerant flows to a header.

For example, in a heat exchanger described in <CIT>, a header having a circular cylindrical internal space and a flow path for allowing a refrigerant that flows in the internal space to flow by being branched toward each flat tube is used.

Document <CIT> discloses a heat exchanger according to the preamble of claim <NUM>.

In headers known in the art, in order to ensure sufficient pressure-resistance strength, a wall portion surrounding the internal space is thick. Therefore, when an opening is to be provided in the wall portion surrounding the internal space so that the internal space and each flat tube communicate with each other, it is difficult to form the opening by a pressing operation, and it is necessary to perform cutting or the like so as to penetrate the wall portion.

According to the present invention the above objective is solved by the features of claim <NUM>.

A heat exchanger according to a first aspect includes a header and a plurality of heat transfer tubes. The header is one to which a gas-refrigerant pipe is connected. The plurality of heat transfer tubes are connected to the header. The header includes a first plate member and a second plate member. The second plate member is stacked on the first plate member in a plate-thickness direction. The first plate member includes a first opening that constitutes an internal space of the header. The second plate member includes a second opening that, together with the first opening, constitutes the internal space of the header. The internal space communicates with the plurality of heat transfer tubes. The first opening includes a portion whose width in a first direction differs from a width of the second opening in the first direction. The first direction is a direction perpendicular to both the plate-thickness direction and a direction in which the plurality of heat transfer tubes are arranged.

As a result of reducing the thickness of one plate member by stacking the first plate member having the first opening and the second plate member having the second opening, the heat exchanger allows the openings to be easily formed. Further, since the first opening includes a portion whose width in the first direction differs from the width of the second opening in the first direction, it is possible to, by dividing into small parts a wall surface on which the pressure of a refrigerant in the internal space acts, disperse stress. Therefore, it is possible to increase the pressure-resistance strength of a gas header to which a gas refrigerant is supplied from the gas-refrigerant pipe.

Further, as a result of reducing the thickness of one plate member by stacking the first plate member having the first opening and the second plate member having the second opening, the heat exchanger allows the openings to be easily formed. Further, since the first opening includes a portion whose width in the first direction differs from the width of the second opening in the first direction, it is possible to, by dividing into small parts a wall surface on which the pressure of a refrigerant in the internal space acts, disperse stress. Therefore, it is possible to increase the pressure-resistance strength of a gas header to which a gas refrigerant is supplied from the gas-refrigerant pipe.

Furthermore, when the internal space is viewed from the connection portions where the header and the heat transfer tubes are connected to each other, by reducing the size of an inner surface that is positioned on an inner side of the first opening, the heat exchanger is capable of increasing the pressure-resistance strength.

Note that, at an inner edge portion of the first opening and an inner edge portion of the second opening, the pressure-receiving surface that faces the internal space can be formed.

By providing, at the surface of the first plate member on the side where the second plate member is stacked, the pressure-receiving surface that extends to the inner side of the width of the second opening in the first direction from the outer side of the width of the first opening in the first direction, the heat exchanger is capable of increasing the pressure-resistance strength.

Note that, when viewed in the plate-thickness direction, the area of the overlapping region where the first opening and the second opening overlap each other is desirably greater than or equal to half of the area of the first opening and greater than or equal to half of the area of the second opening, and is more desirably greater than or equal to <NUM>% of the area of the first opening and greater than or equal to <NUM>% of the area of the second opening.

When viewed in the plate-thickness direction, it is desirable that two end portions of the second opening in the first direction be positioned on outer sides of two end portions of the first opening in the first direction.

The heat exchanger is capable of increasing the pressure-resistance strength of the header having the internal space that communicates with the plurality of heat transfer tubes.

A heat exchanger according to a second aspect is the heat exchanger according to the first aspect, in which the header further includes a third plate member. The third plate member includes a third opening. The third plate member is stacked on the second plate member in the plate-thickness direction. The third plate member is disposed at a position that is closer than the second plate member to the connection portions where the header and the heat transfer tubes are connected to each other. The third opening includes a portion whose width in the first direction is smaller than the width of the second opening in the first direction.

The heat exchanger makes it easy for the flow of a refrigerant to be divided toward each heat transfer tube while allowing the refrigerant to flow in the internal space.

A heat exchanger according to a third aspect is the heat exchanger according to the first aspect or the second aspect, in which, when the header is viewed from the direction in which the plurality of heat transfer tubes are arranged, the first opening and the second opening do not overlap the heat transfer tubes.

Note that it is desirable that the width of the opening in the first direction of the plate member (for example, the third plate member) positioned closest to an end portion of each heat transfer tube be smaller than the width of the heat transfer tubes in the first direction.

The heat exchanger is capable of increasing the pressure-resistance strength at a region in which a refrigerant before flowing by being branched toward each heat transfer tube flows.

A heat exchanger according to a fourth aspect is the heat exchanger according to any one of the first aspect to the third aspect, in which the header further includes an outer member. The outer member includes a plate-shaped portion to which the heat transfer tubes are connected. The outer member includes a first side surface portion and a second side surface portion that extend in the plate-thickness direction from a corresponding one of two ends of the plate-shaped portion in the first direction, and that face each other. The first side surface portion and the second side surface portion sandwich the first plate member and the second plate member. Note that it is desirable that the first side surface portion and the second side surface portion sandwich the first plate member and the second plate member in the first direction. Note that it is desirable that the first side surface portion and the second side surface portion extend toward a side where a first plate-shaped portion and a second plate-shaped portion are disposed.

The heat exchanger is capable of further increasing the pressure-resistance strength of the header.

A heat exchanger according to a fifth aspect is the heat exchanger according to any one of the first aspect to the fourth aspect, in which the first plate member and the second plate member each have a plate thickness of <NUM> or less.

The heat exchanger allows the opening of each plate member to be easily formed.

A heat exchanger according to a sixth aspect is the heat exchanger according to any one of the first aspect to the fifth aspect, in which the plurality of heat transfer tubes are arranged in a longitudinal direction of the header.

Even if the internal space is provided in the longitudinal direction of the header, the heat exchanger is capable of increasing the pressure-resistance strength of the header.

A heat exchanger according to an seventh aspect is the heat exchanger according to any one of the first aspect to the sixth aspect, in which the heat transfer tubes are flat tubes.

A heat pump device according to an eighth aspect includes the heat exchanger according to any one of the first aspect to the seventh aspect.

Since the pressure-resistance strength of the header of the heat exchanger is high, the heat pump device can be more reliable.

A heat pump device according to a ninth aspect is the heat pump device according to the eighth aspect and includes a refrigerant circuit. The refrigerant circuit includes the heat exchanger. A carbon dioxide refrigerant circulates in the refrigerant circuit.

When a refrigeration cycle is performed by circulating a carbon dioxide refrigerant in the refrigerant circuit, although the high pressure in the refrigeration cycle tends to be high, even in this case, the pressure-resistance strength of the header of the heat exchanger is high, as a result of which the heat pump device can be more reliable.

An embodiment of an air conditioner using a heat exchanger of the present invention is described below.

An air conditioner <NUM> is described with reference to the drawings.

<FIG> is a schematic structural view of the air conditioner <NUM> including a heat exchanger according to an embodiment of the present invention as an outdoor heat exchanger <NUM>.

The air conditioner <NUM> (an example of the heat pump device) is a device that cools and heats a space to be air-conditioned by performing a vapor-compression refrigeration cycle. The space to be air-conditioned is, for example, a space in buildings, such as office buildings, commercial facilities, or residences. Note that the air conditioner is merely one example of a refrigerant cycle device, and the heat exchanger of the present invention may be used in other refrigerant cycle devices, such as a refrigerator, a freezer, a water heater, or a floor heating device.

As shown in <FIG>, the air conditioner <NUM> mainly includes a refrigerant circuit <NUM>, an outdoor fan <NUM>, an indoor fan <NUM>, and a control unit <NUM> that controls devices that constitute the refrigerant circuit <NUM>, the outdoor fan <NUM>, and the indoor fan <NUM>.

The refrigerant circuit <NUM> mainly includes an accumulator <NUM>, a compressor <NUM>, a four-way switching valve <NUM>, an outdoor heat exchanger <NUM>, an expansion valve <NUM>, and an indoor heat exchanger <NUM>.

A refrigerant is sealed in the refrigerant circuit <NUM>. As the refrigerant, for example, a carbon dioxide refrigerant can be used. When a refrigeration cycle is performed by circulating a carbon dioxide refrigerant in the refrigerant circuit <NUM>, the carbon dioxide refrigerant is used so as to be temporarily in a supercritical state.

The compressor <NUM> is a device that sucks in a refrigerant having a low pressure in a refrigeration cycle, compresses the refrigerant at a compression mechanism (not shown), and discharges the compressed refrigerant.

The four-way switching valve <NUM> is a mechanism that, by switching a direction of flow of a refrigerant, changes the state of the refrigerant circuit <NUM> between a cooling operation state and a heating operation state. When the refrigerant circuit <NUM> is in the cooling operation state, the outdoor heat exchanger <NUM> functions as a heat dissipater (condenser) of a refrigerant and the indoor heat exchanger <NUM> functions as an evaporator of a refrigerant. When the refrigerant circuit <NUM> is in the heating operation state, the outdoor heat exchanger <NUM> functions as an evaporator of a refrigerant and the indoor heat exchanger <NUM> functions as a condenser of a refrigerant. When the state of the refrigerant circuit <NUM> is the cooling operation state, the four-way switching valve <NUM> is switched to a connection state shown by a solid line in the four-way switching valve <NUM> of <FIG>, and when the state of the refrigerant circuit <NUM> is the heating operation state, the four-way switching valve <NUM> is switched to a connection state shown by a broken line in the four-way switching valve <NUM> of <FIG>.

The outdoor heat exchanger <NUM> (an example of the heat exchanger) is a device that is disposed outside a space to be air-conditioned and causes a refrigerant that flows in the outdoor heat exchanger and outdoor air (heat source air) to exchange heat with each other. The outdoor heat exchanger <NUM> is described in detail below.

A gas refrigerant side of the outdoor heat exchanger <NUM> is connected to the four-way switching valve <NUM> via a gas-refrigerant pipe <NUM>, and a liquid refrigerant side of the outdoor heat exchanger <NUM> is connected to the expansion valve <NUM> via a liquid-refrigerant pipe <NUM>.

The expansion valve <NUM> is disposed between the outdoor heat exchanger <NUM> and the indoor heat exchanger <NUM> in the refrigerant circuit <NUM>. The expansion valve <NUM> adjusts the pressure and the flow rate of a refrigerant that flows in the liquid-refrigerant pipe <NUM>.

The accumulator <NUM> is a container having a gas-liquid dividing function of dividing a refrigerant that flows in into a gas refrigerant and a liquid refrigerant.

In the indoor heat exchanger <NUM>, a refrigerant that flows in the indoor heat exchanger <NUM> and air in a space to be air-conditioned exchange heat with each other. Although the type of indoor heat exchanger <NUM> is not limited, the indoor heat exchanger <NUM> is, for example, a fin-and-tube heat exchanger including a plurality of heat transfer tubes and fins that are not shown. Note that a plurality of the indoor heat exchangers <NUM> may be disposed in parallel in the refrigerant circuit <NUM>.

The outdoor fan <NUM> is a fan that supplies heat source air to the outdoor heat exchanger <NUM> and that generates an air flow for discharging air that has exchanged heat with a refrigerant in the outdoor heat exchanger <NUM>.

The indoor fan <NUM> is a fan that supplies air in a space to be air-conditioned to the indoor heat exchanger <NUM> and that generates an air flow for blowing air that has exchanged heat with a refrigerant in the indoor heat exchanger <NUM> to the space to be air-conditioned.

The control unit <NUM> is a functional part that controls the operations of various devices that constitute the air conditioner <NUM>. The control unit <NUM> is, for example, a microcomputer or a unit including, for example, a memory that stores various programs for controlling the air conditioner <NUM>, which are executable by the microcomputer.

As shown in <FIG>, the control unit <NUM> is electrically connected to various devices including the compressor <NUM>, the four-way switching valve <NUM>, the expansion valve <NUM>, the outdoor fan <NUM>, and the indoor fan <NUM>. The control unit <NUM> is electrically connected to various sensors (not shown). The control unit <NUM> is constituted to allow communication with a remote controller (not shown) that is operated by a user of the air conditioner <NUM>.

The control unit <NUM> controls the operation and stopping of the air conditioner <NUM> or the operations of the various devices that constitute the air conditioner <NUM>, based on, for example, a measurement signal of each of the various sensors or an instruction that is received from a remote controller (not shown).

A structure of the outdoor heat exchanger <NUM> is described with reference to the drawings.

<FIG> is a schematic perspective view of the outdoor heat exchanger <NUM>. <FIG> is an enlarged view of a portion of a heat exchange portion <NUM> (described below) of the outdoor heat exchanger <NUM>. <FIG> is a schematic view showing fins <NUM> (described below) mounted on flat tubes <NUM> in the heat exchange portion <NUM>. <FIG> is a schematic structural view of the outdoor heat exchanger <NUM>. The arrows in the heat exchange portion <NUM> shown in <FIG> indicate flow of a refrigerant at the time of a heating operation (when the outdoor heat exchanger <NUM> functions as an evaporator).

Note that, in the description below, for describing an orientation and a position, terms, such as "up", "down", "left", "right", "front (front side)", or "back (back side)" may be used. Unless otherwise specified, these terms are in conformity with the directions of the arrows shown in <FIG>. Note that these terms that indicate these directions and positions are used for convenience of explanation, and, unless otherwise specified, the orientation and the position of the entire outdoor heat exchanger <NUM> and the orientation and the position of each structure of the outdoor heat exchanger <NUM> are not to be determined by the orientations and the positions indicated by these terms.

The outdoor heat exchanger <NUM> is a device that causes heat to be exchanged between a refrigerant that flows therein and air.

The outdoor heat exchanger <NUM> mainly includes a distributor <NUM>, a flat tube group <NUM> including the plurality of flat tubes <NUM>, the plurality of fins <NUM>, a liquid header <NUM>, and a gas header <NUM> (an example of the header) (see <FIG> and <FIG>). In the present embodiment, the distributor <NUM>, the flat tubes <NUM>, the fins <NUM>, the liquid header <NUM>, and the gas header <NUM> are all made of aluminum or an aluminum alloy.

As described below, the flat tubes <NUM> and the fins <NUM> that are fixed to the flat tubes <NUM> form the heat exchange portion <NUM> (see <FIG> and <FIG>). The outdoor heat exchanger <NUM> is a device including the one-column heat exchange portion <NUM>, and is not a device in which the plurality of flat tubes <NUM> are arranged in an air flow direction. In the outdoor heat exchanger <NUM>, by causing air to flow in a ventilation path that is formed by the flat tubes <NUM> and the fins <NUM> of the heat exchange portion <NUM>, a refrigerant that flows in the flat tubes <NUM> exchanges heat with the air that flows in the ventilation path. The heat exchange portion <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 arranged in an up-down direction (see <FIG>).

The distributor <NUM> is a mechanism that divides a flow of a refrigerant. The distributor <NUM> is also a mechanism that merges refrigerants. The liquid-refrigerant pipe <NUM> is connected to the distributor <NUM>. The distributor <NUM> includes a plurality of distributing pipes 22a to 22e. The distributor <NUM> has the function of dividing a flow of a refrigerant that has flowed into the distributor <NUM> from the liquid-refrigerant pipe <NUM> by the plurality of distributing pipes 22a to 22e and of guiding the separated portions of the refrigerant to a plurality of spaces that are formed in the liquid header <NUM>. The distributor <NUM> also has the function of merging portions of the refrigerant that have flowed through the distributing pipes 22a to 22e from the liquid header <NUM> and of guiding the merged portions of the refrigerant to the liquid-refrigerant pipe <NUM>.

The flat tube group <NUM> is an example of a heat transfer tube group. The flat tube group <NUM> includes the plurality of flat tubes <NUM> (examples of heat transfer tubes) as a plurality of heat transfer tubes. As shown in <FIG>, the flat tubes <NUM> are flat heat transfer tubes having a flat surface 28a, which is a heat transfer surface, in the up-down direction. The plurality of flat tubes <NUM> are arranged in the up-down direction. As shown in <FIG>, the flat tubes <NUM> have a plurality of refrigerant passages 28b in which a refrigerant flows. For example, the flat tubes <NUM> are flat multi-hole tubes where many refrigerant passages 28b in which a refrigerant flows and whose passage cross-sectional area is small are formed. In the present embodiment, the plurality of refrigerant passages 28b are provided side by side in the air flow direction.

In the outdoor heat exchanger <NUM>, as shown in <FIG>, the flat tubes <NUM> extending in a horizontal direction between the liquid header <NUM> and the gas header <NUM> are arranged in the up-down direction in a plurality of stages. Note that, in the present embodiment, the flat tubes <NUM> extending between the liquid header <NUM> and the gas header <NUM> are bent at two locations, and the heat exchange portion <NUM> that is constituted by the flat tubes <NUM> is formed in a substantially U shape in plan view (see <FIG>). The flat tubes <NUM> extend in a front-back direction (an example of the first direction) at connection portions where the flat tubes <NUM> are connected to the gas header <NUM>, and extend in the front-back direction at connection portions where the flat tubes <NUM> are connected to the liquid header <NUM>. In the present embodiment, the plurality of flat tubes <NUM> are disposed apart from each other by a certain interval in the up-down direction.

The plurality of fins <NUM> are members for increasing the heat transfer area of the outdoor heat exchanger <NUM>. Each fin <NUM> is a plate-shaped member extending in a direction in which the flat tubes <NUM> are arranged in layers. The outdoor heat exchanger <NUM> is used in a mode in which the plurality of flat tubes <NUM> extending in the horizontal direction are arranged in the up-down direction. Therefore, with the outdoor heat exchanger <NUM> being installed, each fin <NUM> extends in the up-down direction.

As shown in <FIG>, a plurality of cut portions 29a extending in an insertion direction of the flat tubes <NUM> are formed in each fin <NUM> to allow the plurality of flat tubes <NUM> to be inserted therein. The cut portions 29a extend in the direction of extension of the fins <NUM> and in a direction orthogonal to a thickness direction of the fins <NUM>. With the outdoor heat exchanger <NUM> being installed, the cut portions 29a in each fin <NUM> extend in the horizontal direction. The shape of the cut portions 29a of the fins <NUM> is substantially the same as the external shape of the cross section of the flat tubes <NUM>. The cut portions 29a are formed in the fins <NUM> to be apart from each other by an interval corresponding to an arrangement interval of the flat tubes <NUM>. In the outdoor heat exchanger <NUM>, the plurality of fins <NUM> are arranged in the direction of extension of the flat tubes <NUM>. By inserting the flat tubes <NUM> into the plurality of cut portions 29a of the plurality of fins <NUM>, portions between the flat tubes <NUM> that are adjacent to each other are separated into a plurality of ventilation paths in which air flows.

Each fin <NUM> includes communication portions 29b communicating with each other in the up-down direction on an upstream side or a downstream side of the air flow direction with respect to the flat tubes <NUM>. In the present embodiment, the communication portions 29b of the fins <NUM> are positioned on a windward side with respect to the flat tubes <NUM>.

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

As shown in <FIG>, one end portion of each flat tube <NUM> is connected to the liquid header <NUM>, and the other end portion of each flat tube <NUM> is connected to the gas header <NUM>. The outdoor heat exchanger <NUM> is disposed in a casing so that longitudinal directions of the substantially quadrangular prism-shaped liquid header <NUM> and gas header <NUM> are substantially the same as a vertical direction. In the present embodiment, as shown in <FIG>, the heat exchange portion <NUM> of the outdoor heat exchanger <NUM> has a U shape in plan view. The liquid header <NUM> is disposed near a left front corner of the casing (see <FIG>). The gas header <NUM> is disposed near a right front corner of the casing (see <FIG>).

The longitudinal direction of the liquid header <NUM> is the up-down direction.

A liquid-side internal space <NUM> of the liquid header <NUM> is 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 are arranged in the up-down direction. The sub-spaces 23a to 23e do not communicate with each other in the liquid-side internal space <NUM> of the liquid header <NUM> as a result of being separated by a corresponding one or corresponding ones of the partition plates <NUM>.

The distributing pipes 22a to 22e of the distributor <NUM> are connected in a one-to-one correspondence to the respective sub-spaces 23a to 23e. Therefore, in a cooling operation state, portions of a refrigerant that have reached the respective sub-spaces 23a to 23e flow into the respective distributing pipes 22a to 22e, and merge at the distributor <NUM>. In a heating operation state, a refrigerant whose flow has been divided at the distributor <NUM> is supplied to each of the sub-spaces 23a to 23e.

The longitudinal direction of the gas header <NUM> is the up-down direction (an example of the second direction).

A single space is formed inside the gas header <NUM>. Partition plates, such as those provided at the liquid header <NUM>, that separate spaces that are arranged in the up-down direction are not provided in a gas-side internal space <NUM> of the gas header <NUM>.

A main gas-refrigerant pipe connection portion 19a and a branch gas-refrigerant pipe connection portion 19b that constitute an end portion of the gas-refrigerant pipe <NUM> on the side of the gas header <NUM> are connected to the gas header <NUM> (see <FIG>). Note that, although not limited, the outside diameter of the main gas-refrigerant pipe connection portion 19a may be, for example, greater than or equal to three times, or greater than or equal to five times the outside diameter of the branch gas-refrigerant pipe connection portion 19b.

One end of the main gas-refrigerant pipe connection portion 19a is connected to the gas header <NUM> to communicate with the gas-side internal space <NUM> at an intermediate position on the gas header <NUM> in a height direction.

One end of the branch gas-refrigerant pipe connection portion 19b is connected to the gas header <NUM> to communicate with the gas-side internal space <NUM> near a lower end of the gas header <NUM> in the height direction. The other end of the branch gas-refrigerant pipe connection portion 19b is connected to the main gas-refrigerant pipe connection portion 19a. With the inside diameter of the branch gas-refrigerant pipe connection portion 19b being smaller than the inside diameter of the main gas-refrigerant pipe connection portion 19a and with the branch gas-refrigerant pipe connection portion 19b being connected to the gas header <NUM> at a location below the main gas-refrigerant pipe connection portion 19a, the branch gas-refrigerant pipe connection portion 19b is capable of bringing refrigerating-machine oil that is retained near the lower end of the gas header <NUM> into the main gas-refrigerant pipe connection portion 19a and returning the refrigerating-machine oil to the compressor <NUM>.

When the air conditioner <NUM> performs a heating operation and thus the outdoor heat exchanger <NUM> functions as an evaporator of a refrigerant, a refrigerant in a gas-liquid two-phase state that has reached the distributor <NUM> from the liquid-refrigerant pipe <NUM> flows through the distributing pipes 22a to 22e and flows into each of the sub-spaces 23a to 23e that constitute the liquid-side internal space <NUM> of the liquid header <NUM>. Specifically, a portion of the refrigerant that has flowed in the distributing pipe 22a flows to the sub-space 23a, a portion of the refrigerant that has flowed in the distributing pipe 22b flows to the sub-space 23b, a portion of the refrigerant that has flowed in the distributing pipe 22c flows to the sub-space 23c, a portion of the refrigerant that has flowed in the distributing pipe 22d flows to the sub-space 23d, and a portion of the refrigerant that has flowed in the distributing pipe 22e flows to the sub-space 23e. The portions of the refrigerant that have flowed into the respective sub-spaces 23a to 23e of the liquid-side internal space <NUM> flow to the corresponding flat tubes <NUM> connected to a corresponding one of the sub-spaces 23a to 23e. The portions of the refrigerant flowing in the respective flat tubes <NUM> exchange heat with air and thus evaporate and become portions of a gas-phase refrigerant, and flow into the gas-side internal space <NUM> of the gas header <NUM> to merge with each other.

When the air conditioner <NUM> performs a cooling operation or a defrost operation, the refrigerant flows in the refrigerant circuit <NUM> in a direction opposite to that when the air conditioner <NUM> performs the heating operation. Specifically, a high-temperature gas-phase refrigerant flows into the gas-side internal space <NUM> of the gas header <NUM> via the main gas-refrigerant pipe connection portion 19a and the branch gas-refrigerant pipe connection portion 19b of the gas-refrigerant pipe <NUM>. The refrigerant that has flowed into the gas-side internal space <NUM> of the gas header <NUM> is divided and flows into each flat tube <NUM>. Portions of the refrigerant that have flowed into the flat tubes <NUM> exchange heat with air and dissipate heat or are condensed, become portions of a liquid refrigerant or a gas-liquid two-phase refrigerant, and flow into a corresponding one of the sub-spaces 23a to 23e of the liquid-side internal space <NUM> of the liquid header <NUM>. The portions of the refrigerant that have flowed into the sub-spaces 23a to 23e of the liquid-side internal space <NUM> merge at the distributor <NUM> and flow out to the liquid-refrigerant pipe <NUM>.

<FIG> is a side external structural view showing a state of connection of the gas-refrigerant pipe <NUM> to the gas header <NUM>. <FIG> is a sectional perspective view in which the gas header <NUM> has been sectioned at the center in a left-right direction. <FIG> is an exploded perspective view of the gas header <NUM>. Note that, in <FIG>, alternate-long-and-two-short-dash-line arrows indicate the flow of a refrigerant when the outdoor heat exchanger <NUM> functions as a heat dissipater or a condenser of the refrigerant. <FIG> is a plan sectional view showing a state of connection of the gas-refrigerant pipe <NUM> and the flat tubes <NUM> to the gas header <NUM>.

<FIG> is a schematic view of a first member <NUM> when seen from a front side thereof (a first claw portion 71d and a second claw portion 71e are not shown). <FIG> is a schematic view of a second member <NUM> when seen from a front side thereof. <FIG> is a schematic view of a third member <NUM> when seen from a front side thereof. <FIG> is a schematic view of a fourth member <NUM> when seen from a front side thereof. <FIG> is a schematic view of a fifth member <NUM> when seen from a front side thereof. <FIG> is a schematic view of a sixth member <NUM> when seen from a front side thereof. <FIG> is a schematic view of a seventh member <NUM> when seen from a front side thereof. Note that, in each of these figures, there are portions shown by, for example, broken lines, while the relationship between the positions of openings of members that are disposed adjacent to each other is projected.

The gas header <NUM> includes a first member <NUM>, a second member <NUM>, a third member <NUM>, a fourth member <NUM>, a fifth member <NUM>, a sixth member <NUM>, and a seventh member <NUM>. The gas header <NUM> is constituted by joining the first member <NUM>, the second member <NUM>, the third member <NUM>, the fourth member <NUM>, the fifth member <NUM>, the sixth member <NUM>, and the seventh member <NUM> to each other by brazing. Note that, although not specified, in the present embodiment, for example, the first member <NUM>, the third member <NUM>, the fifth member <NUM>, and the seventh member <NUM> can each be a member in which an aluminum-alloy plate material is provided with a cladding layer including a brazing material on each of two surfaces in a plate-thickness direction; and the second member <NUM>, the fourth member <NUM>, and the sixth member <NUM> can each be an aluminum-alloy plate material. In this way, by forming a structure in which a plate material that does not include a cladding layer is sandwiched by plate materials that include a cladding layer, it is possible to sufficiently join the members to each other by brazing.

Note that, from the viewpoint that the first member <NUM>, the third member <NUM>, the fourth member <NUM>, the fifth member <NUM>, the sixth member <NUM>, and the seventh member <NUM> can easily have their openings formed by a pressing operation in a plate-thickness direction, it is desirable that these members be constituted to have plate thicknesses that are <NUM> or less. It is desirable that the first member <NUM>, the third member <NUM>, the fourth member <NUM>, the fifth member <NUM>, the sixth member <NUM>, and the seventh member <NUM> each be a member having a thickness in the plate-thickness direction that is smaller than a length in a vertical direction and that is smaller than a length in the left-right direction. The first member <NUM>, the third member <NUM>, the fourth member <NUM>, the fifth member <NUM>, the sixth member <NUM>, and the seventh member <NUM> are stacked in a stacking direction, which is the plate-thickness direction.

An external shape of the gas header <NUM> in plan view is a substantially square shape having the connection portions of the flat tubes <NUM> as one side.

The first member <NUM> is primarily a member that, together with the seventh member <NUM> described below, constitutes the periphery of the external shape of the gas header <NUM>.

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

Although not limited, the first member <NUM> of the present embodiment can be formed by bending one metal plate obtained by rolling with the longitudinal direction of the gas header <NUM> being a direction of fold. In this case, the plate thickness of each portion of the first member <NUM> is uniform.

The flat-tube connection plate 71a is a flat-shaped portion extending in the up-down direction and in the left-right direction. A plurality of flat-tube connection openings 71x arranged in the up-down direction are formed in the flat-tube connection plate 71a. Each flat-tube connection opening 71x is a penetration opening in a thickness direction of the flat-tube connection plate 71a. With the flat tubes <NUM> being inserted in the flat-tube connection openings 71x such that one end of each flat tube <NUM> extends completely through the corresponding flat-tube connection opening 71x, the flat tubes <NUM> are joined to the flat-tube connection openings 71x by brazing. Here, each flat tube <NUM> is mounted on a main surface of the flat-tube connection plate 71a with a longitudinal direction of each flat tube <NUM> being orthogonal to the main surface. In the joined state realized by brazing, the entire inner peripheral surface of each flat-tube connection opening 71x and the entire outer peripheral surface of the corresponding flat tube <NUM> are in contact with each other. Here, since the thickness of the first member <NUM> including the flat-tube connection plate 71a is relatively small, such as on the order of <NUM> or greater and <NUM> or less, the length of the inner peripheral surface of each flat-tube connection opening 71x in the plate-thickness direction can be small. Therefore, when, in a stage before the joining by brazing, the flat tubes <NUM> are inserted into the flat-tube connection openings 71x, friction that is produced between the inner peripheral surfaces of the flat-tube connection openings 71x and the outer peripheral surfaces of the flat tubes <NUM> can be kept low, and the insertion operation can be facilitated.

The first outer wall 71b is a planar-shaped portion extending toward a front side from a front surface of an end portion on a left side (side of the liquid header <NUM>) of the flat-tube connection plate 71a. The second outer wall 71c is a planar-shaped portion extending toward a front side from a front surface of an end portion on a right side (side opposite to the liquid header <NUM>) of the flat-tube connection plate 71a. The first outer wall 71b and the second outer wall 71c sandwich the second member <NUM>, the third member <NUM>, the fourth member <NUM>, the fifth member <NUM>, the sixth member <NUM>, and the seventh member <NUM> from the left-right direction.

The first claw portion 71d is a portion extending toward the right from a front end portion of the first outer wall 71b. The second claw portion 71e is a portion extending toward the left from a front end portion of the second outer wall 71c.

In a state before the second member <NUM>, the third member <NUM>, the fourth member <NUM>, the fifth member <NUM>, the sixth member <NUM>, and the seventh member <NUM> are disposed on an inner side of the first member <NUM> in plan view, the first claw portion 71d and the second claw portion 71e are each in an extended state on an extension line of a corresponding one of the first outer wall 71b and the second outer wall 71c. In a state in which the second member <NUM>, the third member <NUM>, the fourth member <NUM>, the fifth member <NUM>, the sixth member <NUM>, and the seventh member <NUM> are disposed on the inner side of the first member <NUM> in plan view, the first claw portion 71d and the second claw portion 71e are bent toward each other to crimp the second member <NUM>, the third member <NUM>, the fourth member <NUM>, the fifth member <NUM>, the sixth member <NUM>, and the seventh member <NUM> by the first member <NUM>, as a result of which they are fixed to each other. When, in this state, the brazing is performed, for example, inside a furnace, the members are joined to each other by the brazing and are completely fixed to each other.

The second member <NUM> includes a plate-shaped base portion 72a and a plurality of protrusions 72b that protrude toward the flat-tube connection plate 71a from the base portion 72a.

The base portion 72a extends parallel to the flat-tube connection plate 71a and has a plate shape in which the direction of extension of the flat tubes <NUM> from the gas header <NUM> is the plate-thickness direction. The width of the base portion 72a in the left-right direction is the same as the width of a portion of the flat-tube connection plate 71a in the left-right direction excluding two end portions. A plurality of distributing openings 72x provided side by side in the up-down direction are formed in a one-to-one correspondence with the flat tubes <NUM> at positions in the base portion 72a other than the positions where the protrusions 72b are provided. When viewed from the front, the distributing openings 72x have shapes that are substantially the same as those of the end portions of the flat tubes <NUM>.

The protrusions 72b extend in the horizontal direction up to where they come into contact with a front surface of the flat-tube connection plate 71a by extending toward the back from portions of the base portion 72a between the distributing openings 72x adjacent to each other. Therefore, there are formed insertion spaces 25b surrounded by the front surface of the flat-tube connection plate 71a of the first member <NUM>, the first outer wall 71b and the second outer wall 71c of the first member <NUM>, the protrusions 72b of the second member <NUM> that are adjacent to each other in the up-down direction, and portions of a back surface of the base portion 72a of the second member <NUM> other than the distributing openings 72x. The insertion spaces 25b are provided side by side in the longitudinal direction of the gas header <NUM>. End portions of the flat tubes <NUM> are positioned in the corresponding insertion spaces 25b, and the insertion spaces 25b function as chambers for a refrigerant that flows out toward the flat tubes <NUM>. Note that the lengths of the protrusions 72b in the front-back direction are adjusted to be larger than the plate thickness of the first member <NUM>, the third member <NUM>, the fourth member <NUM>, the fifth member <NUM>, the sixth member <NUM>, and the seventh member <NUM> that constitute the gas header <NUM>. Therefore, even if an error occurs in the amount of insertion of the flat tubes <NUM> into the gas header <NUM>, as long as the error is within a range of the lengths of the protrusions 72b in the front-back direction, problems, such as there being portions at which a flow of a refrigerant is blocked or portions at which a refrigerant has difficulty flowing when the gas header <NUM> has been completed, are less likely to occur. It is also possible to suppress a brazing material from moving due to a capillary action when the members are joined by brazing, and to thus suppress the brazing material from closing the refrigerant passages 28b of the flat tubes <NUM>.

Note that the gas-side internal space <NUM> of the gas header <NUM> includes the insertion spaces 25b, which are space portions disposed more toward the flat tubes <NUM> than the base portion 72a, and a distributing space 25a, which is a space portion disposed farther than the base portion 72a on a side opposite to the flat tubes <NUM>.

The third member <NUM> is a plate-shaped member that is stacked on a surface on a front side (side at which the gas-refrigerant pipe <NUM> and the gas header <NUM> are connected to each other) of the base portion 72a of the second member <NUM> so as to face and contact this surface.

The third member <NUM> (an example of the third member) includes a third internal plate 73a and a third internal opening 73x (an example of the third opening).

The third internal plate 73a has a flat shape extending in the up-down direction and in the left-right direction. The third internal plate 73a has a left-right width and an up-down width that are the same as those of the base portion 72a of the second member <NUM>.

The third internal opening 73x is a penetration opening in the plate-thickness direction of the third internal plate 73a. It is desirable that the third internal opening 73x be formed by punching a plate-shaped member. In the present embodiment, the third internal opening 73x is formed with a large size near the center of the third internal plate 73a in the up-down direction and in the left-right direction. A longitudinal direction of the third internal opening 73x is the up-down direction, and, when viewed from the front, is a rectangular opening. When viewed from the front, the third internal opening 73x overlaps a part of each distributing opening 72x of the second member <NUM> and communicates therewith. Note that the width of the third internal opening 73x in the left-right direction is smaller than the width of each distributing opening 72x of the second member <NUM> in the left-right direction, and that, when viewed from the front, two ends of the third internal opening 73x in the left-right direction are positioned inward of two ends of each distributing opening 72x of the second member <NUM> in the left-right direction. Therefore, a refrigerant that flows in the distributing space 25a can be made to flow by being branched toward the plurality of distributing openings 72x of the second member <NUM>, and the flow of the refrigerant can be divided with respect to each flat tube <NUM> connected to a corresponding one of the distributing openings 72x.

The third internal opening 73x includes a third upper edge surface 73u, a third lower edge surface 73d, a third left edge surface <NUM>, and a third right edge surface 73r, which serve as rims at an inner periphery of the opening.

A back surface of the third internal plate 73a is in surface-contact with a front surface of the base portion 72a of the second member <NUM>. A part of a front surface of the third internal plate 73a is in surface-contact with a back surface of a fourth internal plate 74a (described below), and the other portions of the front surface of the third internal plate 73a that are not in surface-contact with the back surface of the fourth internal plate 74a are a third left exposed surface <NUM> and a third right exposed surface <NUM> that face backward. The third left exposed surface <NUM> is a surface that, at a portion of the front surface of the third internal plate 73a that is disposed more toward the left than the third left edge surface <NUM> of the third internal opening 73x, extends in the up-down direction along the third left edge surface <NUM>. The third right exposed surface <NUM> is a surface that, at a portion of the front surface of the third internal plate 73a that is disposed more toward the right than the third right edge surface 73r of the third internal opening 73x, extends in the up-down direction along the third right edge surface 73r. In the present embodiment, the width of the third left exposed surface <NUM> in the left-right direction and the width of the third right exposed surface <NUM> in the left-right direction may be the same, and are desirably <NUM>/<NUM> or greater and <NUM> times or less of the plate thickness of the third member <NUM>.

The fourth member <NUM> is a plate-shaped member that is stacked on the surface on a front side (side at which the gas-refrigerant pipe <NUM> and the gas header <NUM> are connected to each other) of the third internal plate 73a of the third member <NUM> so as to face and contact this surface.

The fourth member <NUM> (an example of the second member) includes a fourth internal plate 74a and a fourth internal opening 74x.

The fourth internal plate 74a has a flat shape extending in the up-down direction and in the left-right direction. Similarly to the third internal plate 73a, the fourth internal plate 74a has a left-right width and an up-down width that are the same as those of the base portion 72a of the second member <NUM>.

The fourth internal opening 74x is a penetration opening in the plate-thickness direction of the fourth internal plate 74a. It is desirable that the fourth internal opening 74x be formed by punching a plate-shaped member. In the present embodiment, the fourth internal opening 74x is formed with a large size near the center of the fourth internal plate 74a in the up-down direction and in the left-right direction. A longitudinal direction of the fourth internal opening 74x is the up-down direction, and, when viewed from the front, is a rectangular opening. When viewed from the front, the fourth internal opening 74x overlaps a part of the third internal opening 73x of the third member <NUM> and communicates therewith. Note that the width of the fourth internal opening 74x in the left-right direction is larger than the width of the third internal opening 73x of the third member <NUM> in the left-right direction, and that, when viewed from the front, two ends of the fourth internal opening 74x in the left-right direction are positioned outward of the two ends of the third internal opening 73x in the left-right direction.

The fourth internal opening 74x includes a fourth upper edge surface 74u, a fourth lower edge surface 74d, a fourth left edge surface <NUM>, and a fourth right edge surface 74r, which serve as rims at an inner periphery of the opening.

When viewed from the front, the fourth upper edge surface 74u overlaps the third upper edge surface 73u, and the fourth lower edge surface 74d overlaps the third lower edge surface 73d.

The back surface of the fourth internal plate 74a is in surface-contact with portions, other than the third left exposed surface <NUM> and the third right exposed surface <NUM>, of the front surface of the third internal plate 73a of the third member <NUM>. A front surface of the fourth internal plate 74a is in surface-contact with a part of a back surface of the fifth internal plate 75a (described below).

The fifth member <NUM> is a plate-shaped member that is stacked on the surface on a front side (side at which the gas-refrigerant pipe <NUM> and the gas header <NUM> are connected to each other) of the fourth internal plate 74a of the fourth member <NUM> so as to face and contact this surface.

The fifth member <NUM> (an example of the first member) includes a fifth internal plate 75a and a fifth internal opening 75x (an example of the first opening).

The fifth internal plate 75a has a flat shape extending in the up-down direction and in the left-right direction. Similarly to the third internal plate 73a and the fourth internal plate 74a, the fifth internal plate 75a has a left-right width and an up-down width that are the same as those of the base portion 72a of the second member <NUM>.

The fifth internal opening 75x is a penetration opening in the plate-thickness direction of the fifth internal plate 75a. It is desirable that the fifth internal opening 75x be formed by punching a plate-shaped member. In the present embodiment, the fifth internal opening 75x is formed with a large size near the center of the fifth internal plate 75a in the up-down direction and in the left-right direction. A longitudinal direction of the fifth internal opening 75x is the up-down direction, and, when viewed from the front, is a rectangular opening. When viewed from the front, the fifth internal opening 75x overlaps a part of the fourth internal opening 74x of the fourth member <NUM> and communicates therewith. Note that the width of the fifth internal opening 75x in the left-right direction is smaller than the width of the fourth internal opening 74x of the fourth member <NUM> in the left-right direction, and that, when viewed from the front, two ends of the fifth internal opening 75x in the left-right direction are positioned inward of the two ends of the fourth internal opening 74x in the left-right direction.

The fifth internal opening 75x includes a fifth upper edge surface 75u, a fifth lower edge surface 75d, a fifth left edge surface <NUM>, and a fifth right edge surface 75r, which serve as rims at an inner periphery of the opening.

When viewed from the front, the fifth upper edge surface 75u overlaps the fourth upper edge surface 74u, and the fifth lower edge surface 75d overlaps the fourth lower edge surface 74d.

Note that, in the present embodiment, when viewed from the front, the fifth left edge surface <NUM> overlaps the third left edge surface <NUM>, and the fifth right edge surface 75r overlaps the third right edge surface 73r.

A part of the back surface of the fifth internal plate 75a is in surface-contact with the front surface of the fourth internal plate 74a. Other portions of the back surface of the fifth internal plate 75a that are not in surface-contact with the front surface of the fourth internal plate 74a are a fifth left exposed surface <NUM> and a fifth right exposed surface <NUM> that face backward. The fifth left exposed surface <NUM> is a surface that, at a portion of the back surface of the fifth internal plate 75a that is disposed more toward the left than the fifth left edge surface <NUM> of the fifth internal opening 75x, extends in the up-down direction along the fifth left edge surface <NUM>. The fifth right exposed surface <NUM> is a surface that, at a portion of the back surface of the fifth internal plate 75a that is disposed more toward the right than the fifth right edge surface 75r of the fifth internal opening 75x, extends in the up-down direction along the fifth right edge surface 75r. In the present embodiment, the width of the fifth left exposed surface <NUM> in the left-right direction and the width of the fifth right exposed surface <NUM> in the left-right direction may be the same, and are desirably <NUM>/<NUM> or greater and <NUM> times or less of the plate thickness of the fifth member <NUM>.

Note that a front surface of the fifth internal plate 75a is in surface-contact with a part of a back surface of the sixth internal plate 76a (described below).

The sixth member <NUM> is a plate-shaped member that is stacked on the surface on a front side (side at which the gas-refrigerant pipe <NUM> and the gas header <NUM> are connected to each other) of the fifth internal plate 75a of the fifth member <NUM> so as to face and contact this surface.

The sixth member <NUM> includes a sixth internal plate 76a and a sixth internal opening 76x.

The sixth internal plate 76a has a flat shape extending in the up-down direction and in the left-right direction. Similarly to the third internal plate 73a, the fourth internal plate 74a, and the fifth internal plate 75a, the sixth internal plate 76a has a left-right width and an up-down width that are the same as those of the base portion 72a of the second member <NUM>.

The sixth internal opening 76x is a penetration opening in the plate-thickness direction of the sixth internal plate 76a. It is desirable that the sixth internal opening 76x be formed by punching a plate-shaped member. In the present embodiment, the sixth internal opening 76x is formed with a large size near the center of the sixth internal plate 76a in the up-down direction and in the left-right direction. A longitudinal direction of the sixth internal opening 76x is the up-down direction, and, when viewed from the front, is a rectangular opening. When viewed from the front, the sixth internal opening 76x overlaps a part of the fifth internal opening 75x of the fifth member <NUM> and communicates therewith. Note that the width of the sixth internal opening 76x in the left-right direction is smaller than the width of the fifth internal opening 75x of the fifth member <NUM> in the left-right direction, and that, when viewed from the front, two ends of the sixth internal opening 76x in the left-right direction are positioned inward of the two ends of the fifth internal opening 75x in the left-right direction.

The sixth internal opening 76x includes a sixth upper edge surface 76u, a sixth lower edge surface 76d, a sixth left edge surface <NUM>, and a sixth right edge surface 76r, which serve as rims at an inner periphery of the opening.

When viewed from the front, the sixth upper edge surface 76u overlaps the fifth upper edge surface 75u, and the sixth lower edge surface 76d overlaps the fifth lower edge surface 75d.

A part of the back surface of the sixth internal plate 76a is in surface-contact with the front surface of the fifth internal plate 75a. Other portions of the back surface of the sixth internal plate 76a that are not in surface-contact with the front surface of the fifth internal plate 75a are a sixth left exposed surface <NUM> and a sixth right exposed surface <NUM> that face backward. The sixth left exposed surface <NUM> is a surface that, at a portion of the back surface of the sixth internal plate 76a that is disposed more toward the left than the sixth left edge surface <NUM> of the sixth internal opening 76x, extends in the up-down direction along the sixth left edge surface <NUM>. The sixth right exposed surface <NUM> is a surface that, at a portion of the back surface of the sixth internal plate 76a that is disposed more toward the right than the sixth right edge surface 76r of the sixth internal opening 76x, extends in the up-down direction along the sixth right edge surface 76r. In the present embodiment, the width of the sixth left exposed surface <NUM> in the left-right direction and the width of the sixth right exposed surface <NUM> in the left-right direction may be the same, and are desirably <NUM>/<NUM> or greater and <NUM> times or less of the plate thickness of the sixth member <NUM>.

Note that a front surface of the sixth internal plate 76a is in surface-contact with a part of a back surface of an external plate 77a (described below).

The seventh member <NUM> is a plate-shaped member that is stacked on the surface on a front side (side at which the gas-refrigerant pipe <NUM> and the gas header <NUM> are connected to each other) of the sixth internal plate 76a of the sixth member <NUM> so as to face and contact this surface.

The seventh member <NUM> includes the external plate 77a, a main gas-pipe connection opening 77x, and a branch gas-pipe connection opening 77y.

The external plate 77a has a flat shape extending in the up-down direction and in the left-right direction. Similarly to the third internal plate 73a, the fourth internal plate 74a, the fifth internal plate 75a, and the sixth internal plate 76a, the external plate 77a has a left-right width and an up-down width that are the same as those of the base portion 72a of the second member <NUM>. The external plate 77a covers from the front the distributing space 25a of the gas-side internal space <NUM> of the gas header <NUM>. The plate thickness of the external plate 77a can be the same as the plate thicknesses of internal plates, such as the third internal plate 73a, the fourth internal plate 74a, the fifth internal plate 75a, and the sixth internal plate 76a.

The main gas-pipe connection opening 77x is a penetration opening in the plate-thickness direction near the center of the external plate 77a in the up-down direction and in the left-right direction. When viewed from the front, a large portion of the main gas-pipe connection opening 77x overlaps the sixth internal opening 76x of the sixth member <NUM> and communicates therewith. Note that the branch gas-pipe connection opening 77y is provided below the main gas-pipe connection opening 77x, and, when viewed from the front, overlaps the sixth internal opening 76x of the sixth member <NUM> and communicates therewith.

The main gas-pipe connection opening 77x is a circular opening to which an end portion of the main gas-refrigerant pipe-connection portion 19a is connected. The branch gas-pipe connection opening 77y is a circular opening to which an end portion of the branch gas-refrigerant pipe connection portion 19b is connected.

Note that a front surface of the seventh member <NUM> is in contact with and crimped to the first claw portion 71d and the second claw portion 71e of the first member <NUM>.

(<NUM>-<NUM>)
In the gas header <NUM> of the outdoor heat exchanger <NUM> of the present embodiment, the distributing space 25a of the gas-side internal space <NUM> is formed by the plate-shaped third member <NUM>, the plate-shaped fourth member <NUM>, the plate-shaped fifth member <NUM>, and the plate-shaped sixth member <NUM>. The third internal opening 73x of the third member <NUM>, the fourth internal opening 74x of the fourth member <NUM>, the fifth internal opening 75x of the fifth member <NUM>, and the sixth internal opening 76x of the sixth member <NUM> are constituted to have different opening widths in the left-right direction. Therefore, portions of adjacent plate-shaped members that do not overlap each other (the third left exposed surface <NUM>, the third right exposed surface <NUM>, the fifth left exposed surface <NUM>, the fifth right exposed surface <NUM>, the sixth left exposed surface <NUM>, the sixth right exposed surface <NUM>) can be formed.

Therefore, the distributing space 25a of the gas-side internal space <NUM> has a structure that includes, as pressure-receiving surfaces that are subjected to the pressure of a refrigerant in the inside thereof, not only the third upper edge surface 73u, the third lower edge surface 73d, the third left edge surface <NUM>, and the third right edge surface 73r of the third internal opening 73x, the fourth upper edge surface 74u, the fourth lower edge surface 74d, the fourth left edge surface <NUM>, and the fourth right edge surface 74r of the fourth internal opening 74x, the fifth upper edge surface 75u, the fifth lower edge surface 75d, the fifth left edge surface <NUM>, and the fifth right edge surface 75r of the fifth internal opening 75x, and the sixth upper edge surface 76u, the sixth lower edge surface 76d, the sixth left edge surface <NUM>, and the sixth right edge surface 76r of the sixth internal opening 76x, but also the third left exposed surface <NUM>, the third right exposed surface <NUM>, the fifth left exposed surface <NUM>, the fifth right exposed surface <NUM>, the sixth left exposed surface <NUM>, and the sixth right exposed surface <NUM>. Therefore, the pressure of a refrigerant in the distributing space 25a of the gas-side internal space <NUM> can be dispersed and received at many pressure-receiving surfaces thereof, and the pressure-resistance strength can be increased by dispersing stress.

Since such a mechanism that increases the pressure-resistance strength is used in the gas header <NUM> of the outdoor heat exchanger <NUM>, even if a high-pressure gas refrigerant discharged from the compressor <NUM> is supplied, the gas header <NUM> can be more reliable.

In this way, by constituting the distributing space 25a by a layered body including the third internal plate 73a to the sixth internal plate 76a, it is possible to reduce the plate thickness per internal plate. Therefore, the third internal opening 73x to the seventh internal opening 76x of the third internal plate 73a to the sixth internal plate 76a can be easily formed by a simple pressing operation without the necessity of a cutting operation or other operations.

(<NUM>-<NUM>)
The gas header <NUM> of the outdoor heat exchanger <NUM> of the present embodiment has a structure in which the opening width in the left-right direction at the third internal opening 73x, the fourth internal opening 74x, the fifth internal opening 75x, and the sixth internal opening 76x decrease after increasing once toward the back. Therefore, it is possible to further effectively disperse stress and to increase the pressure-resistance strength. Further, by making small the left-right width of the sixth internal opening 76x, it is possible to narrow a plane of the back surface of the external plate 77a exposed to the distributing space 25a. Therefore, even if the plate thickness of the seventh member <NUM> is not large, it is possible to ensure pressure-resistance strength. Consequently, the main gas-pipe connection opening 77x and the branch gas-pipe connection opening 77y of the seventh member <NUM> can be easily formed by a simple pressing operation without the necessity of a cutting operation or other operations.

(<NUM>-<NUM>)
In the gas header <NUM> of the outdoor heat exchanger <NUM> of the present embodiment, the structure of increasing the pressure-resistance strength by using different opening widths as described above is applied not to the small insertion spaces 25b, which are separated for the respective flat tubes <NUM>, of the gas-side internal space <NUM> of the gas header <NUM>, but to the distributing space 25a, in which a large amount of refrigerant flows and which is a wider space. In this way, in the wide space, the pressure-receiving surfaces for partitioning the wide space tend to be widened and the pressure-resistance strength tends to be required. However, in the present embodiment, since the structure that increases the pressure-resistance strength above is used at locations where the pressure-resistance strength is further required, the effects of increasing the pressure-resistance strength can be sufficiently provided.

(<NUM>-<NUM>)
In the gas header <NUM> of the outdoor heat exchanger <NUM> of the present embodiment, the second member <NUM> to the seventh member <NUM> are brought together by the first member <NUM> as a result of being surrounded by the first member <NUM>, and are joined to each other by brazing. Therefore, it is possible to further increase the pressure-resistance strength as the gas header <NUM>.

(<NUM>-<NUM>)
In the gas header <NUM> of the outdoor heat exchanger <NUM> of the present embodiment, the third internal opening 73x to the sixth internal opening 76x are formed near the center in the left-right direction and the up-down direction. Therefore, it is possible to sufficiently ensure the portions around the openings of the third member <NUM> to the sixth member <NUM>. Consequently, even from this point, it is possible to further increase the pressure-resistance strength of the gas header <NUM>.

(<NUM>-<NUM>)
In the air conditioner <NUM> of the present embodiment, carbon dioxide used as a refrigerant is used so as to be temporarily in a supercritical state in a refrigeration cycle. In this way, even when used with the refrigerant pressure in the refrigerant circuit <NUM> being in a high state, since the pressure-resistance strength of the gas header <NUM> is increased as described above, the air conditioner <NUM> can be more reliable.

(<NUM>-<NUM>)
In cylindrical gas headers known in the art, when flat tubes, which are flat heat transfer tubes, are to be inserted, the flat tubes need to be inserted by a large amount into the gas header so that the entire end portion of each flat tube is positioned inside the cylindrical gas header. Therefore, in the inside of cylindrical gas headers, useless space where a refrigerant is retained is formed above and below the end portions of the flat tubes. This tendency becomes noticeable with increasing width of the flat tubes.

In contrast, in the gas header <NUM> of the outdoor heat exchanger <NUM> of the present embodiment, the flat-tube-connection plate 71a of the first member <NUM> has a plate shape, and the flat tubes <NUM> are inserted perpendicularly to the flat-tube-connection plate 71a.

Therefore, since the gas header <NUM> of the outdoor heat exchanger <NUM> of the present embodiment has a structure that is established as long as even if an end of each flat tube <NUM> is inserted slightly beyond the flat-tube-connection plate 71a of the first member <NUM>, useless space where a refrigerant is retained can be small around the end portion of each flat tube <NUM>.

(<NUM>-<NUM>)
In the gas header <NUM> of the outdoor heat exchanger <NUM> of the present embodiment, the first member <NUM> including the flat-tube-connection plate 71a is relatively thin. Therefore, when, in a stage before the joining by brazing, the flat tubes <NUM> are inserted into the flat-tube connection openings 71x, friction that is produced between the inner peripheral surfaces of the flat-tube connection openings 71x and the outer peripheral surfaces of the flat tubes <NUM> can be kept low, and the insertion operation can be facilitated.

Even if the first member <NUM> including the flat-tube-connection plate 71a is thin, since the gas-side internal space <NUM> of the gas header <NUM> is constituted by stacking the plate-shaped members <NUM> to <NUM>, it is possible to increase the pressure-resistance strength of the gas header <NUM>.

In the embodiment above, an example in which the third internal opening 73x to the sixth internal opening 76x of the gas header <NUM> are formed near the center in the left-right direction has been given and described.

In contrast, the third internal opening 73x to the sixth internal opening 76x may be formed, for example, to be disposed toward an upstream side of a flow of air that is supplied to a heat exchanger. In this case, since a larger amount of refrigerant can be supplied to a windward side where the temperature difference between a refrigerant and air is considerable, it is possible to increase heat exchange efficiency.

In the embodiment above, an example in which carbon dioxide is used as a refrigerant has been given and described.

In contrast, the refrigerant is not limited thereto, and, for example, a refrigerant, such as R32 or 410A, may be used.

In the embodiment above, an example in which the edge portions of the opening of each internal plate each face a corresponding one of the upward direction, the downward direction, the rightward direction, and the leftward direction, and are planes parallel to the plate-thickness direction has been given and described.

In contrast, the edge portions of the opening of each internal plate may be planes that are not parallel to the plate-thickness direction, or may not constitute planes as a result of, for example, being curved.

In the embodiment above, an example of a structure in which, when viewed from the front, the third internal opening 73x and the fifth internal opening 75x are completely disposed within the fourth internal opening 74x has been given and described.

In contrast, the relationship between each internal opening is not limited thereto, and, for example, when viewed from the front, the third internal opening 73x and the fifth internal opening 75x may each have a portion that does not overlap the fourth internal opening 74x, and the fourth internal opening 74x may also have a portion that does not overlap the third internal opening 73x and the fifth internal opening 75x.

In the embodiment above, an example in which, when viewed from the front, the third internal opening 73x to the sixth internal opening 76x have rectangular shapes has been given and described.

Claim 1:
A heat exchanger (<NUM>) comprising:
a header (<NUM>) to which a gas-refrigerant pipe (<NUM>) is connected; and
a plurality of heat transfer tubes (<NUM>) that are connected to the header,
wherein the header (<NUM>) includes a first plate member (<NUM>) and a second plate member (<NUM>, <NUM>) that is stacked on the first plate member (<NUM>) in a plate-thickness direction,
wherein the first plate member (<NUM>) includes a first opening (75x) that constitutes an internal space (<NUM>) of the header (<NUM>),
wherein the second plate member (<NUM>, <NUM>) includes a second opening (74x, 176x) that, together with the first opening (75x), constitutes the internal space (<NUM>) of the header (<NUM>),
wherein the internal space (<NUM>) communicates with the plurality of heat transfer tubes (<NUM>), and
wherein the first opening (75x) includes a portion whose width in a first direction perpendicular to both the plate-thickness direction and a direction in which the plurality of heat transfer tubes (<NUM>) are arranged differs from a width of the second opening (74x) in the first direction,
wherein the second plate member (<NUM>, <NUM>) is disposed at a position that is closer than the first plate member (<NUM>) to connection portions where the header (<NUM>) and the heat transfer tubes (<NUM>) are connected to each other, and
wherein the second opening (74x) includes a portion whose width in the first direction is larger than the width of the first opening (75x) in the first direction, and,
wherein the first plate member (<NUM>) includes, at a surface on a side at which the second plate member (<NUM>, <NUM>) is stacked, a pressure-receiving surface that extends to an inner side of the width of the second opening (74x) in the first direction from an outer side of the width of the first opening (75x) in the first direction, and that faces the internal space (<NUM>),
characterized in that, when viewed in the plate-thickness direction, an overlapping region of the first opening (75x) and the second opening (74x) overlaps a cross section of each connection portion of two or more of the heat transfer tubes (<NUM>) connecting to the header (<NUM>) at each connection portion.