Patent Description:
There has been known a heat exchanger having pairs of mutually facing heat transfer tubes. In the pairs, the heat transfer tubes in a first row and the heat transfer tubes in a second row extend parallel to one another. Regarding such a heat exchanger, a bridging header into which end portions of the heat transfer tubes are inserted has flow passages. In each of the flow passages, refrigerant flows only between a pair of the heat transfer tubes. That is, in the bridging header, the refrigerant that has flowed into the bridging header from a heat transfer tube arranged in the first row does not merge with the flow of the refrigerant that has flowed into the bridging header from another heat transfer tube arranged in the first row. Patent Literature <NUM> <CIT> discloses a heat exchanger having a base into which heat transfer tubes are inserted and a bridging header constituted by a corrugated sheet that is provided on the base and that has a wavy shape in which semicircular column portions are continuously formed. Each of the semicircular column portions of the corrugated sheet covers points at which the paired heat transfer tubes are inserted and forms a flow passage between the semicircular column portion and the base.

Patent Literature <NUM> <CIT>, which is considered as the closest prior art, discloses in a heat exchanger, an outside air passage, through which outside air flows, is provided between adjacent tubes of the refrigerant tube and the coolant tubes. Disposed in the outside air passage is an outer fin joined to at least one of the refrigerant tube and the coolant tube and configured to accelerate heat transfer between the fluids. A dimension of the refrigerant tube in a flow direction of the outside air is different from a dimension of the coolant tube in the flow direction of the outside air. Hence, with respect to the outer fin joined to both of the refrigerant tube and the coolant tube, an area of a joint surface between the refrigerant tube and the outer fin is different from an area of a joint surface between the coolant tube and the outer fin.

Patent Literature <NUM> <CIT> discloses an evaporator for an air conditioning apparatus has an upper and a lower tanks and multiple tubes vertically extending and respectively connected to the tanks at upper and lower ends. A fluid passage portion is formed in the lower tank. Multiple drainage recesses are formed in the lower tank at such portions, at which the recesses do not interfere with the fluid passage portion.

However, the corrugated sheet of the heat exchanger of Patent Literature <NUM> is required to be thickened so as not to be deformed by the pressure of the refrigerant flowing through the bridging header. In most cases, a thickened corrugated sheet is likely to interfere with the inserted heat transfer tube and is likely to cover, in a hindering way, a point at which the heat transfer tube is inserted. In the heat exchanger of the Patent Literature <NUM>, because being thickened, the corrugated sheet reduces a region, in the base, into which the heat transfer tubes can be inserted. Thus, regarding the heat exchanger of Patent Literature <NUM>, for example, the number of the heat transfer tubes that are inserted into the bridging header and a space between the heat transfer tubes are limited, and design flexibility is thus decreased.

The present disclosure has been made to solve such an above-described problem and provides: a heat exchanger enabling adjustment of, for example, the number of the heat transfer tubes that are inserted into a bridging header and a space between the heat transfer tubes and thus enabling increase in design flexibility; and a method of manufacturing the heat exchanger.

A heat exchanger of one embodiment of the present disclosure has: a heat transfer tube group made up of plural heat transfer tubes each of which has, inside the heat transfer tube, a flow passage through which refrigerant flows, the plural heat transfer tubes that are arranged in a lateral direction being arranged in a longitudinal direction so as to form plural rows; a fin provided on the heat transfer tubes and facilitating heat exchange between refrigerant flowing inside the heat transfer tubes and air; and a bridging header into which end portions of the heat transfer tubes are inserted and that causes refrigerant to flow between the heat transfer tubes arranged in a lateral direction of the heat transfer tube group. The bridging header has a base having a flat plate shape and having insertion holes into which respective ones of end portions of the plurality of heat transfer tubes are inserted. The bridging header also has a corrugated sheet being a plate having a shape of a wave in which crest portions and valley portions are continuously formed, each of the crest portions being provided so as to cover a pair of the insertion holes arranged in a lateral direction, the valley portions being in contact with the base on both sides of each of the insertion holes in a longitudinal direction of the base, the corrugated sheet forming, between the corrugated sheet and the base, a header flow passage, through which refrigerant flows, for every the heat transfer tubes arranged in a lateral direction of the heat transfer tube group. The bridging header also has a covering plate covering the corrugated sheet and pressing the corrugated sheet toward the base.

A method of manufacturing a heat exchanger of another embodiment of the present disclosure includes: assembling: a heat transfer tube group made up of plural heat transfer tubes each of which has, inside the heat transfer tube, a flow passage through which refrigerant flows, the plural heat transfer tubes that are arranged in a lateral direction being arranged in a longitudinal direction so as to form plural rows; a fin provided on the heat transfer tubes and facilitating heat exchange between refrigerant flowing inside the heat transfer tubes and air; and a bridging header into which end portions of the heat transfer tubes are inserted and that causes refrigerant to flow between the heat transfer tubes arranged in a lateral direction of the heat transfer tube group. The method also includes performing brazing of the heat transfer tube group, the fin, and the bridging header. The assembling includes: fitting the corrugated sheet of the bridging header into the base, of the bridging header, having insertion holes into which respective ones of end portions of the plurality of heat transfer tubes are inserted, the fitting being performed so that, in the corrugated sheet being a plate having a shape of a wave in which crest portions and valley portions are continuously formed, each of the crest portions covers a pair of the insertion holes arranged in a lateral direction, and the valley portions are in contact with the base on both sides of each of the insertion holes in a longitudinal direction of the base; and carrying out attachment of a covering plate so that the covering plate covers the corrugated sheet.

According to an embodiment of the present disclosure, the bridging header has the covering plate that presses the corrugated sheet toward the base. Thus, the corrugated sheet is suppressed from being deformed by the pressure of the refrigerant flowing through the bridging header. That is, for suppressing the corrugated sheet from being deformed by the pressure of the refrigerant flowing through the bridging header, the corrugated sheet is not required to be thickened. Consequently, regarding the heat exchanger, for example, the number of the heat transfer tubes that are inserted into the bridging header and a space between the heat transfer tubes can be adjusted, and design flexibility can thus be increased.

Hereinafter, an air-conditioning apparatus <NUM> provided with a heat exchanger <NUM> according to Embodiment <NUM> will be described with reference to the drawings. In addition, the heat exchanger <NUM> may be provided for an apparatus other than the air-conditioning apparatus <NUM>. <FIG> is a circuit diagram of the air-conditioning apparatus <NUM> according to Embodiment <NUM>. As <FIG> illustrates, the air-conditioning apparatus <NUM> has an outdoor unit <NUM>, an indoor unit <NUM>, and a refrigerant pipe <NUM>. Note that, although <FIG> illustrates the single indoor unit <NUM>, the number of the indoor units <NUM> may be two or more.

The outdoor unit <NUM> includes a compressor <NUM>, a flow-switching device <NUM>, the heat exchanger <NUM>, an outdoor fan <NUM>, and an expansion unit <NUM>. The indoor unit <NUM> includes an indoor heat exchanger <NUM> and an indoor fan <NUM>. The refrigerant pipe <NUM> constitutes a refrigerant circuit by connecting the compressor <NUM>, the flow-switching device <NUM>, the heat exchanger <NUM>, the expansion unit <NUM>, and the indoor heat exchanger <NUM> to one another and by allowing refrigerant to flow inside the refrigerant pipe <NUM>.

The compressor <NUM> sucks low-temperature and low-pressure refrigerant, compresses the sucked refrigerant to bring the refrigerant into a high-temperature and high-pressure state, and discharges the refrigerant. The flow-switching device <NUM> switches flowing directions of refrigerant in the refrigerant circuit and is, for example, a four-way valve. The heat exchanger <NUM> exchanges heat between refrigerant and outdoor air. The heat exchanger <NUM> operates as a condenser during a cooling operation and operates as an evaporator during a heating operation. The outdoor fan <NUM> is a device for sending outdoor air to the heat exchanger <NUM>. The expansion unit <NUM> is a pressure-reducing valve or an expansion valve for reducing the pressure of refrigerant to expand the refrigerant.

The indoor heat exchanger <NUM> exchanges heat between indoor air and refrigerant. The indoor heat exchanger <NUM> operates as an evaporator during the cooling operation and operates as a condenser during the heating operation. The indoor fan <NUM> is a device for sending indoor air to the indoor heat exchanger <NUM>.

Here, an operation of the air-conditioning apparatus <NUM> will be described. First, the cooling operation will be described. In the cooling operation, the refrigerant sucked into the compressor <NUM> is compressed by the compressor <NUM>, and the refrigerant that has turned into a high-temperature and high-pressure gas state is discharged from the compressor <NUM>. The high-temperature and high-pressure gas state refrigerant that has been discharged from the compressor <NUM> passes through the flow-switching device <NUM> and flows into the heat exchanger <NUM> operating as a condenser. The refrigerant that has flowed into the heat exchanger <NUM> exchanges heat with the outdoor air sent by the outdoor fan <NUM> and is thus condensed to be liquefied. The refrigerant in a liquid state flows into the expansion unit <NUM> and is reduced in pressure and expanded to turn into a low-temperature and low-pressure two-phase gas-liquid state. The refrigerant in a gas-liquid two-phase state flows into the indoor heat exchanger <NUM> operating as an evaporator. The refrigerant that has flowed into the indoor heat exchanger <NUM> exchanges heat with the indoor air sent by the indoor fan <NUM> and is thus evaporated to be gasified. At this time, the indoor air is cooled and air cooling is performed in a room. Subsequently, the evaporated refrigerant in a low-temperature and low-pressure gas state passes through the flow-switching device <NUM> and is sucked into the compressor <NUM>.

Next, the heating operation will be described. In the heating operation, the refrigerant sucked into the compressor <NUM> is compressed by the compressor <NUM>, and the refrigerant that has turned into a high-temperature and high-pressure gas state is discharged from the compressor <NUM>. The high-temperature and high-pressure gas state refrigerant that has been discharged from the compressor <NUM> passes through the flow-switching device <NUM> and flows into the indoor heat exchanger <NUM> operating as a condenser. The refrigerant that has flowed into the indoor heat exchanger <NUM> exchanges heat with the indoor air sent by the indoor fan <NUM> and is thus condensed to be liquefied. At this time, the indoor air is heated and air heating is performed in the room. The refrigerant in a liquid state flows into the expansion unit <NUM> and is reduced in pressure and expanded to turn into a low-temperature and low-pressure two-phase gas-liquid state. The refrigerant in a gas-liquid two-phase state flows into the heat exchanger <NUM> operating as an evaporator. The refrigerant that has flowed into the heat exchanger <NUM> exchanges heat with the outdoor air sent by the outdoor fan <NUM> and is thus evaporated to be gasified. Subsequently, the evaporated refrigerant in a low-temperature and low-pressure gas state passes through the flow-switching device <NUM> and is sucked into the compressor <NUM>.

<FIG> is a perspective view of the heat exchanger <NUM> according to Embodiment <NUM>. Here, the configuration of the heat exchanger <NUM> will be described in detail. The heat exchanger <NUM> has a heat transfer tube group <NUM>, a fin <NUM>, a first lower header <NUM>, a bridging header <NUM>, and a second lower header <NUM>. Note that a configuration similar to the configuration of the heat exchanger <NUM> may be applied to the indoor heat exchanger <NUM>.

The heat transfer tube group <NUM> is constituted by plural heat transfer tubes <NUM>. The heat transfer tubes <NUM> arranged in the lateral direction are arranged in the longitudinal direction so as to form plural rows. The heat transfer tubes <NUM> are, for example, flat tubes and have plural flow passages (not illustrated) inside which refrigerant flows. In Embodiment <NUM>, each of the heat transfer tubes <NUM> extends in the vertical direction. Note that the heat transfer tube <NUM> may alternatively extend in a direction other than the vertical direction. In this case, other parts of the heat exchanger <NUM> are also assembled based on the direction where the heat transfer tube <NUM> extends. In addition, in Embodiment <NUM>, the heat transfer tubes <NUM> form two rows that are a first row and a second row extending parallel to one another. Note that the heat transfer tubes <NUM> may extend in three or more rows. The fin <NUM>, which is, for example, a corrugated fin, is provided on the heat transfer tubes <NUM> and facilitates heat exchange between the refrigerant flowing inside the heat transfer tubes <NUM> and air.

The first lower header <NUM> is a header into which an end portion on one side of each of the heat transfer tubes <NUM> arranged in the first row is inserted. The refrigerant pipe <NUM> is connected to the first lower header <NUM>. The first lower header <NUM> distributes the refrigerant that has flowed into the first lower header <NUM> from the refrigerant pipe <NUM> to the heat transfer tubes <NUM> arranged in the first row. The first lower header <NUM> also causes the refrigerant that has merged with the refrigerant flow in the first lower header <NUM> from the heat transfer tubes <NUM> arranged in the first row to flow out into the refrigerant pipe <NUM>.

The bridging header <NUM> is a header that faces the first lower header <NUM> and the second lower header <NUM> and into which an end portion on the other side of each of the heat transfer tubes <NUM> arranged in the first row and in the second row is inserted. The bridging header <NUM> distributes the refrigerant that has merged with the refrigerant flow in the bridging header <NUM> from a heat transfer tube <NUM> arranged in the first row to a heat transfer tube <NUM> arranged in the second row. The bridging header <NUM> also distributes the refrigerant that has merged with the refrigerant flow in the bridging header <NUM> from the heat transfer tube <NUM> arranged in the second row to the heat transfer tube <NUM> arranged in the first row and facing, in the lateral direction, the heat transfer tube <NUM> arranged in the second row.

<FIG> is a side view of the bridging header <NUM> according to Embodiment <NUM>. <FIG> illustrates the bridging header <NUM>, when the bridging header <NUM> is viewed in the longitudinal direction. <FIG> is a perspective view of the bridging header <NUM> according to Embodiment <NUM>. <FIG> is a perspective view of the bridging header <NUM> according to Embodiment <NUM>. Note that, in <FIG>, a covering plate <NUM> is transparent for an illustration purpose. As <FIG> illustrate, the bridging header <NUM> has a base <NUM>, a corrugated sheet <NUM>, the covering plate <NUM>, and an end plate <NUM>.

<FIG> is a perspective view of the base <NUM> according to Embodiment <NUM>. <FIG> is a perspective view of the base <NUM> according to Embodiment <NUM>. As <FIG> and <FIG> illustrate, the base <NUM> is a flat plate-shaped part into which the heat transfer tubes <NUM> are inserted. The base <NUM> is constituted by a bottom base <NUM> and a side base <NUM>. The bottom base <NUM> is a plate-shaped part constituting the bottom of the base <NUM> and having plural insertion holes <NUM> and a plate hole <NUM>. The insertion holes <NUM> are openings into which the end portions of the heat transfer tubes <NUM> are inserted. In Embodiment <NUM>, regarding the insertion holes <NUM>, two holes are arranged in the lateral direction and are paired. The insertion holes <NUM> are further arranged, in two rows, in the longitudinal direction. The plate hole <NUM> is an opening into which the end plate <NUM> is fitted. The plate hole <NUM> is opened substantially throughout the width of the bottom base <NUM> in the lateral direction. The side base <NUM> is a plate-shaped part constituting a side of the base <NUM> and extending, from an edge portion of the bottom base <NUM>, along an edge of the corrugated sheet <NUM> extending in the longitudinal direction. Two side bases <NUM> are provided in the longitudinal direction of the heat exchanger <NUM>. Each of the side bases <NUM> has plural claw portions <NUM> and plural catching protrusions <NUM>.

<FIG> illustrates the configuration of the bridging header <NUM> according to Embodiment <NUM>. <FIG> is a perspective view of the bridging header <NUM> according to Embodiment <NUM>. <FIG> illustrates the section of the bridging header <NUM> taken in the A-A direction illustrated in <FIG>. That is, <FIG> illustrates the section of the bridging header <NUM> taken in the longitudinal direction. Note that, in <FIG>, the covering plate <NUM> is transparent, and the corrugated sheet <NUM> is semitransparent. As <FIG> and <FIG> illustrate, each of the claw portions <NUM> is a claw-shaped part protruding from an upper end portion of the side base <NUM> toward the covering plate <NUM>. The claw portion <NUM> is in contact with a surface of the covering plate <NUM> facing the corrugated sheet <NUM> and presses the covering plate <NUM> toward the corrugated sheet <NUM>. As <FIG> and <FIG> illustrates, each of the catching protrusions <NUM> is a substantially hollow cylindrical part protruding from an inner wall surface of the side base <NUM>. The catching protrusions <NUM> catches upper end portions, in the lateral direction, crest portions <NUM> of the corrugated sheet <NUM>, which will be described later. Note that the side base <NUM> may have no catching protrusion <NUM>.

As <FIG> and <FIG> illustrate, the corrugated sheet <NUM> is a sheet having a shape of a wave in which the crest portions <NUM> and valley portions <NUM> are continuously formed. Each of the crest portions <NUM> forms an arch shape in an upper region of the corrugated sheet <NUM>. Each of the valley portions <NUM> forms an arch shape in a lower region of the corrugated sheet <NUM>. Each of the crest portions <NUM> covers a pair of the insertion holes <NUM> arranged in the lateral direction of the heat transfer tube group <NUM>. That is, a header flow passage <NUM> through which refrigerant flows is formed, between each of the crest portions <NUM> and the base <NUM>, for every the heat transfer tubes <NUM> arranged in the lateral direction of the heat transfer tube group <NUM>. In addition, the uppermost portion of the crest portion <NUM> is in contact with the covering plate <NUM>. In the longitudinal direction of the bridging header <NUM>, the lowermost portions of the valley portions <NUM> are in contact with the base <NUM> on both sides of each of the insertion holes <NUM>. In addition, a planar region of the corrugated sheet <NUM>, that is, a portion of the corrugated sheet, other than the rounded portion near the peak of the crest portion <NUM> and the rounded portion near the peak of the valley portion <NUM>, is referred to as a planar portion <NUM>. The corrugated sheet <NUM> has plural planar portions <NUM> separated from one another by the rounded shapes near the peaks of the crest portions <NUM> and the valley portions <NUM>.

The end plate <NUM> is a flat plate-shaped part provided beside the corrugated sheet <NUM>. The end plate <NUM> is fixed to the base <NUM> by being fitted into the plate hole <NUM> formed in the base <NUM>. The end plate <NUM> supports a side portion of the covering plate <NUM>. The end plate <NUM> has an engagement protrusion <NUM>. The engagement protrusion <NUM> protrudes upward from the upper end face of the end plate <NUM>. The engagement protrusion <NUM> is engaged with an engagement hole <NUM> of the covering plate <NUM>, which will be described later. Note that the end plate <NUM> may have no engagement protrusion <NUM>.

The covering plate <NUM> is a flat plate-shaped part covering the corrugated sheet <NUM>. The covering plate <NUM> is provided, in an upper region of the bridging header <NUM>, between two side bases <NUM>. In addition, the covering plate <NUM> presses the corrugated sheet <NUM> toward the base <NUM>. Moreover, the covering plate <NUM> forms a cover space <NUM> between the covering plate <NUM> and the corrugated sheet <NUM>. A side portion of the covering plate <NUM> has the engagement hole <NUM>. The engagement hole <NUM> is an opening into which the engagement protrusion <NUM> of the end plate <NUM> is inserted.

The second lower header <NUM> is a header that is arranged parallel to the first lower header <NUM> and into which an end portion on one side of each of the heat transfer tubes <NUM> arranged in the second row is inserted. The refrigerant pipe <NUM> is connected to the second lower header <NUM>. The second lower header <NUM> distributes the refrigerant that has flowed into the second lower header <NUM> from the refrigerant pipe <NUM> to the heat transfer tubes <NUM> arranged in the second row. The second lower header <NUM> also causes the refrigerant that has merged with the refrigerant flow in the second lower header <NUM> from the heat transfer tubes <NUM> arranged in the second row to flow out into the refrigerant pipe <NUM>. Note that, regarding the heat exchanger <NUM>, the first lower header <NUM> and the second lower header <NUM> may be formed as one body and may have, in a central portion, a partition part (not illustrated) that partitions the inner space of the first lower header <NUM> and the second lower header <NUM>.

Here, a method of manufacturing the heat exchanger <NUM> will be described. Note that each of the base <NUM> of the bridging header <NUM>, the fin <NUM>, the first lower header <NUM>, and the second lower header <NUM> is made of a clad material formed by pressure-bonding of a metal for brazing being performed. First, each of the parts of the heat exchanger <NUM> is formed into a predetermined shape. Here, for example, the corrugated sheet <NUM> is cut out as a rectangular flat plate having a predetermined size and is then processed into a wavy shape. Regarding the base <NUM>, the insertion holes <NUM> and the engagement protrusions <NUM>, for example, are formed, and the base <NUM> is then bent to have the bottom base <NUM> and the side bases <NUM>.

Next, each of the parts of the heat exchanger <NUM> is assembled. Specifically, first, the corrugated sheet <NUM> is fitted in the base <NUM> of the bridging header <NUM>. Due to such assembly, each of the crest portions <NUM> covers a pair of the insertion holes <NUM> arranged in the lateral direction, and, in the longitudinal direction of the base <NUM>, the valley portions <NUM> come into contact with the base <NUM> on both sides of each of the insertion holes <NUM>. Next, the end plate <NUM> is inserted into the plate hole <NUM> of the base <NUM>. Subsequently, the covering plate <NUM> is attached to the base <NUM> so as to cover the corrugated sheet <NUM>. At this time, the engagement protrusion <NUM> of the end plate <NUM> is inserted into the engagement hole <NUM> of the covering plate <NUM>. The claw portions <NUM> of the side bases <NUM> are bent, and the bridging header <NUM> is thus assembled.

Furthermore, the fin <NUM> is provided between each two of the plural heat transfer tubes <NUM>, and the heat transfer tubes <NUM> are inserted into the bridging header <NUM>, into the first lower header <NUM>, and into the second lower header <NUM>. Thus, the entire heat exchanger <NUM> is assembled. The assembled heat exchanger <NUM> is then placed in a brazing apparatus and is subjected to brazing. The upper limit brazing temperature may be set at a temperature that is higher than the solidus temperature of an Al-Si alloy, which is typically used as a brazing material, and at which an Al base metal is not melted, that is, for example, a temperature higher than <NUM> degrees C and lower than <NUM> degrees C. Due to such brazing, the clad material being subjected to pressure-bonding is melted, and each of the parts of the heat exchanger <NUM> is fixed. In the above-described way, the heat exchanger <NUM> is manufactured.

Note that the sequence of the processes of the above-described manufacturing method may be appropriately changed. For example, only the bridging header <NUM> may be fixed, by brazing, ahead. In addition, although the example of the base <NUM>, of the bridging header <NUM>, made of a clad material has been described, the end plate <NUM> and the covering plate <NUM>, in addition to the base <NUM>, may also be made of a clad material. Alternatively, only the corrugated sheet <NUM> may be made of a clad material. In addition to the bridging header <NUM>, in the entire heat exchanger <NUM>, the selection of which part is made of a clad material may be adjusted appropriately.

According to Embodiment <NUM>, the bridging header <NUM> has the covering plate <NUM> pressing the corrugated sheet <NUM> toward the base <NUM>. Thus, the corrugated sheet <NUM> is suppressed from being deformed by the pressure of the refrigerant flowing through the bridging header <NUM>. That is, for suppressing the corrugated sheet <NUM> from being deformed by the pressure of the refrigerant flowing through the bridging header <NUM>, the corrugated sheet <NUM> is not required to be thickened. Consequently, regarding the heat exchanger <NUM>, for example, the number of the heat transfer tubes <NUM> that are inserted into the bridging header <NUM> and a space between the heat transfer tubes <NUM> can be adjusted, and design flexibility can thus be increased.

More specifically, the covering plate <NUM> presses each of the crest portions <NUM> of the corrugated sheet <NUM>. Due to such pressing, the crest portions <NUM> are uniform in height even when tolerances on the heights of the crest portions <NUM> arise through the manufacturing of the corrugated sheet <NUM>. That is, the corrugated sheet <NUM> has, at any point thereof, a constant strength against the refrigerant flowing through each of the header flow passages <NUM>, thereby having less points at which the corrugated sheet <NUM> is likely to be broken. Thus, the heat exchanger <NUM> is hardly broken by the pressure of the refrigerant flowing through the bridging header <NUM>.

In addition, according to Embodiment <NUM>, the side base <NUM> has the claw portions <NUM>. Each of the claw portions <NUM> is in contact with a surface of the covering plate <NUM> facing the corrugated sheet <NUM> and presses the covering plate <NUM> toward the corrugated sheet <NUM>. Thus, because being further strongly pressed by the covering plate <NUM>, the corrugated sheet <NUM> is further suppressed from being deformed by the pressure of the refrigerant flowing through the bridging header <NUM>. That is, the corrugated sheet <NUM> is not required to be thickened. Consequently, regarding the heat exchanger <NUM>, for example, the number of the heat transfer tubes <NUM> that are inserted into the bridging header <NUM> and a space between the heat transfer tubes <NUM> can be adjusted, and design flexibility can thus be increased.

Furthermore, according to Embodiment <NUM>, the side base <NUM> has the catching protrusion <NUM>. In most cases, when a corrugated sheet is long, there may be a crest portion, of the corrugated sheet, being at a position at which the crest portion does not cover an insertion hole due to tolerances, on the corrugated sheet, arising in the longitudinal direction. Here, the side base <NUM> of Embodiment <NUM> has the catching protrusion <NUM>. Thus, with the bridging header <NUM>, it is possible to determine accurately the position at which the corrugated sheet <NUM> is provided and to fix the corrugated sheet, by end portions, in the lateral direction, of the crest portion <NUM> being caught by the catching protrusions <NUM>. Accordingly, the heat exchanger <NUM> of Embodiment <NUM> can be upsized when, for example, a large number of the heat transfer tubes <NUM> are provided, and a long corrugated sheet <NUM> is thus required.

<FIG> is a perspective view of the bridging header <NUM> according to a modification of Embodiment <NUM>. As <FIG> illustrates, the bridging header <NUM> has a leg portion <NUM>. The leg portion <NUM> is a plate-shaped part extending in the vertical direction of the heat exchanger <NUM> and supporting the heat exchanger <NUM>.

<FIG> illustrates the configuration of the bridging header <NUM> according to a modification of Embodiment <NUM>. As with <FIG>, <FIG> illustrates the section of the bridging header <NUM> taken in the longitudinal direction. As <FIG> illustrates, the bridging header <NUM> has a partition plate <NUM>. The partition plate <NUM> is a flat plate-shaped part provided in the bridging header <NUM> so as to partition the bridging header <NUM> into portions in the longitudinal direction. Note that two or more partition plates <NUM> may be provided. The partition plate <NUM> separates the flow of the refrigerant on one side of the partition plate <NUM> from the flow of the refrigerant on the other side of the partition plate <NUM>. In addition, the partition plate <NUM> has a thickness large enough not to be deformed even when there is a large difference in pressure between the refrigerants on one side and on the other side of the partition plate <NUM>. Thus, in regions on both sides of the partition plate <NUM>, the heat exchanger <NUM> can cause the refrigerants having different pressures to flow without the corrugated sheet <NUM> being deformed, as with the case where plural refrigerant pipes <NUM> constituting different refrigerant circuits are connected.

<FIG> is a perspective view of a bridging header <NUM> according to Embodiment <NUM>. Note that, in <FIG>, a covering plate <NUM> is transparent for an illustration purpose. Embodiment <NUM> differs from Embodiment <NUM> in that a corrugated sheet <NUM> has a corrugated-sheet hole <NUM> as <FIG> illustrates. In Embodiment <NUM>, by the same parts as the parts of Embodiment <NUM> being denoted by the same references, the description thereof will be omitted, and differences from Embodiment <NUM> will be mainly described.

<FIG> is a perspective view of the bridging header <NUM> according to Embodiment <NUM>. <FIG> is a perspective view of the bridging header <NUM> according to Embodiment <NUM>. As <FIG> illustrate, the bridging header <NUM> has a base <NUM>, the corrugated sheet <NUM>, and the covering plate <NUM>. The bridging header <NUM> has no end plate. Note that the bridging header <NUM> may have an end plate <NUM>.

<FIG> illustrates the configuration of the bridging header <NUM> according to Embodiment <NUM>. As with <FIG> and <FIG>, <FIG> illustrates the section of the bridging header <NUM> taken in the longitudinal direction. As <FIG> and <FIG> illustrate, each of the planar portions <NUM> of the corrugated sheet <NUM> has the corrugated-sheet hole <NUM>. The corrugated-sheet hole <NUM> is an opening through which refrigerant flows between the header flow passage <NUM> and the cover space <NUM>. Thus, the cover space <NUM> is filled with the refrigerant that has flowed out from the header flow passage <NUM> through the corrugated-sheet hole <NUM>. In addition, the header flow passage <NUM> is filled with the refrigerant flowing between the heat transfer tubes <NUM> facing one another in the lateral direction. That is, with the corrugated-sheet hole <NUM>, the refrigerants in the header flow passage <NUM> and in the cover space <NUM> have uniform pressure. Note that the size of the corrugated-sheet hole <NUM> is set within a range in which the corrugated-sheet hole <NUM> is not closed by a molten metal when the fixation of a heat exchanger <NUM> is performed by brazing.

The covering plate <NUM> is constituted by an upper covering plate <NUM> and a side covering plate <NUM>. The upper covering plate <NUM> is a plate covering the upper side of the corrugated sheet <NUM>. The upper covering plate <NUM> presses the corrugated sheet <NUM> toward the base <NUM>. The side covering plate <NUM> is a plate covering a side portion of the corrugated sheet <NUM>. The side covering plate <NUM> is fixed to the base <NUM> by being fitted into the plate hole <NUM> formed in the base <NUM>. That is, the side covering plate <NUM> has a function similar to the function of the end plate <NUM> of Embodiment <NUM>. Note that the covering plate <NUM> may be constituted by only the upper covering plate <NUM> when the bridging header <NUM> has an end plate <NUM>.

<FIG> is a perspective view of the covering plate <NUM> according to Embodiment <NUM>. <FIG> is a perspective view of the bridging header <NUM> according to Embodiment <NUM>. As <FIG> and <FIG> illustrate, the covering plate <NUM> may have a shape elongated toward end portions, in the longitudinal direction, of the bridging header <NUM>. In this case, in the heat exchanger <NUM>, the base <NUM> and the covering plate <NUM> can be fixed to one another regardless of the thickness of the covering plate <NUM>.

According to Embodiment <NUM>, the corrugated sheet <NUM> has the corrugated-sheet hole <NUM>. Thus, the cover space <NUM> is filled with the refrigerant that has flowed out from the header flow passage <NUM> through the corrugated-sheet hole <NUM>. In addition, the header flow passage <NUM> is filled with the refrigerant flowing between the heat transfer tubes <NUM> facing one another in the lateral direction. That is, the refrigerants in the header flow passage <NUM> and in the cover space <NUM> have uniform pressure. Thus, the corrugated sheet <NUM> is further suppressed from being deformed by the pressure of the refrigerant flowing through the header flow passage <NUM> and is thus not required to be thickened. Consequently, regarding the heat exchanger <NUM>, for example, the number of the heat transfer tubes <NUM> that are inserted into the bridging header <NUM> and a space between the heat transfer tubes <NUM> can be adjusted, and design flexibility can thus be increased.

<FIG> is a perspective view of a corrugated sheet <NUM> according to Embodiment <NUM>. Embodiment <NUM> differs from Embodiment <NUM> in that a corrugated-sheet hole <NUM> is formed in an end portion, in the lateral direction, of the corrugated sheet <NUM> as <FIG> illustrates. In Embodiment <NUM>, by the same parts as the parts of Embodiment <NUM> being denoted by the same references, the description thereof will be omitted, and differences from Embodiment <NUM> will be mainly described.

The corrugated-sheet hole <NUM> has a semicircular shape and is formed at each of both the end portions of the corrugated sheet <NUM> in the lateral direction. Thus, for example, a portion of the refrigerant flowing through the header flow passage <NUM> flows out from the corrugated-sheet hole <NUM> positioned on one side and flows into the cover space <NUM>, and a portion of the refrigerant flowing through the cover space <NUM> flows out from the corrugated-sheet hole <NUM> positioned on the other side and flows into the header flow passage <NUM>. That is, the refrigerant circulates between the header flow passage <NUM> and the cover space <NUM>. Thus, the refrigerants in the header flow passage <NUM> and in the cover space <NUM> have further uniform pressure.

<FIG> illustrates a method of manufacturing a heat exchanger <NUM> according to Embodiment <NUM>. <FIG> illustrates a bridging header <NUM> when the bridging header <NUM> is viewed in the longitudinal direction. In addition, <FIG> illustrates, for simple description, only the bottom base <NUM>, the side base <NUM>, and the corrugated sheet <NUM> are illustrated. The base <NUM> is a clad material, and a brazing material is pressure-bonded to an inner surface of the side base <NUM>, that is, a surface to be in contact with the corrugated sheet <NUM>. In Embodiment <NUM>, as <FIG> illustrates, the bridging header <NUM> is disposed so that the side bases <NUM> are positioned above and below across the corrugated sheet <NUM>, and brazing is performed.

In addition, a corrugated-sheet hole <NUM> before brazing is referred to as a before-heating hole. That is, the corrugated-sheet hole <NUM> is a hole into which the before-heating hole is deformed by the brazing of the bridging header <NUM>. Hereinafter, a preferable dimension of the before-heating hole that is applicable in Embodiment <NUM> will be described. The before-heating hole is processed, for example, at the same time as uniformization of the length, in the lateral direction, of the corrugated sheet <NUM>. The before-heating hole is formed in each of the upper region and the lower region of the corrugated sheet <NUM> and has a semicircular shape. When a distinction between the before-heating hole on the upper side and the before-heating hole on the lower side is required to be made, in the description, different references denote the before-heating holes, that is, the lower hole is referred to as a before-heating hole 280d, and the upper hole is referred to as a before-heating hole 280u. The width of the lower before-heating hole 280d, that is, the width of a region in which the corrugated sheet <NUM> and the side base <NUM> on the lower side are not in contact with one another is referred to as a width Wd. Because the before-heating hole 280d has a semicircular shape, the distance from the side base <NUM> on the lower side to the outer edge of the lower before-heating hole 280d reaches a maximum distance of Wd/<NUM> at a central portion Cd of the outer edge. Similarly, the width of the upper before-heating hole 280u, that is, the width of a region in which the corrugated sheet <NUM> and the side base <NUM> on the upper side are not in contact with one another is referred to as a width Wu. Because the before-heating hole 280u has a semicircular shape, the distance from the side base <NUM> on the upper side to the outer edge of the upper before-heating hole 280u reaches a maximum distance of Wu/<NUM> at a central portion Cu of the outer edge.

Here, the presence or absence of closure of the before-heating hole caused by brazing will be described. Typically, in brazing, a molten brazing material flows into and fill the before-heating hole, and the before-heating hole may thereby be closed. <FIG> illustrates the presence or absence of closure of the before-heating hole 280d on the lower side caused by brazing according to Embodiment <NUM>, for each of the widths Wd of the before-heating holes and for each of the peak temperatures. Similarly, <FIG> illustrates the presence or absence of closure of the before-heating hole 280u on the upper side caused by brazing according to Embodiment <NUM>, for each of the widths Wu of the before-heating holes and for each of the peak temperatures. In <FIG> and <FIG>, as <FIG> illustrates, the presence or absence of closure of the before-heating hole when brazing is performed with the side bases <NUM> of clad material being positioned above and below the corrugated sheet <NUM> is verified for each of the widths of the before-heating holes and for each of the peak temperatures, and the presence or absence of closure of the before-heating hole is plotted. <FIG> illustrates the case of the lower before-heating hole 280d, and <FIG> illustrates the case of the upper before-heating hole 280u.

As <FIG> and <FIG> illustrate, it has been found that even a before-heating hole whose width W is larger is closed as the peak temperature of brazing is increased. It has also been found that there is a difference in a width with which an opening is closed, between the upper before-heating hole and the lower before-heating hole. Specifically, when heating is performed at the same peak temperature, in the case of the lower before-heating hole 280d, closure occurs in a before-heating hole whose width Wd is larger, compared with the case of the upper before-heating hole 280u. The difference between the cases is caused by an incident in which, when the molten clad material flowing, by gravitation, along the corrugated sheet <NUM>, the molten clad material flows into the lower before-heating hole 280d formed at a position below the upper before-heating hole 280u.

<FIG> is a side view of the corrugated sheet <NUM> after brazing according to Embodiment <NUM>. <FIG> illustrates the corrugated sheet <NUM> when the corrugated sheet <NUM> is viewed in the longitudinal direction. The broken line represents a before-heating hole. As <FIG> illustrates, even when before-heating holes having the same width are formed in two end portions, in the lateral direction, of the corrugated sheet <NUM> before brazing, the corrugated-sheet holes <NUM> after brazing have different widths depending on the orientation of the bridging header <NUM> during brazing. That is, viewing such a matter from a different angle, the before-heating hole 280u positioned on the upper side during brazing is hardly closed even when having a width Wu smaller than the width of the before-heating hole 280d positioned on the lower side. Specifically, as <FIG> and <FIG> illustrate, regarding the upper before-heating hole 280u, the width Wu has room for reduction by <NUM> to reach a width with which closure is caused, compared with the lower before-heating hole 280d that is brazed at the same peak temperature. Thus, for example, the width Wu of the before-heating hole 280u positioned on the upper side may be <NUM> smaller than the width of the before-heating hole 280d positioned on the lower side.

Moreover, as <FIG> illustrates, even the lower before-heating hole 280d that is likely to be closed is suppressed from being closed when a width of <NUM> is ensured. In addition, the before-heating hole is formed in the planar portion <NUM> so as not to extend over a rounded portion of the corrugated sheet <NUM>. Thus, where L is a dimension, in the lateral direction, of the planar portion <NUM> of the corrugated sheet <NUM>, the before-heating hole can be within the range from <NUM> to L - processing tolerance mm. The processing tolerance is, for example, <NUM>.

According to Embodiment <NUM>, the corrugated-sheet holes <NUM> are formed in both the end portions, in the lateral direction, of the corrugated sheet <NUM>. Thus, for example, a portion of the refrigerant flowing through the header flow passage <NUM> flows out from the corrugated-sheet hole <NUM> positioned on one side and flows into the cover space <NUM>, and a portion of the refrigerant flowing through the cover space <NUM> flows out from the corrugated-sheet hole <NUM> positioned on the other side and flows into the header flow passage <NUM>. That is, the refrigerant circulates between the header flow passage <NUM> and the cover space <NUM>, and the pressure of the refrigerant is further maintained uniform. Thus, the corrugated sheet <NUM> is further suppressed from being deformed by the pressure of the refrigerant flowing through the header flow passage <NUM> and is thus not required to be thickened. Consequently, regarding the heat exchanger <NUM>, for example, the number of the heat transfer tubes <NUM> that are inserted into the bridging header <NUM> and a space between the heat transfer tubes <NUM> can be adjusted, and design flexibility can thus be increased.

In addition, the corrugated-sheet hole <NUM> may be processed at the same time as the processing performed when the length, in the lateral direction, of the corrugated sheet <NUM> is uniformized. In this case, regarding the heat exchanger <NUM>, the time and effort for processing can be reduced.

According to the method of manufacturing the heat exchanger <NUM> of Embodiment <NUM>, the width Wu of the before-heating hole 280u positioned on the upper side during brazing is smaller than the width Wd of the before-heating hole 280d positioned on the lower side during brazing. Thus, while the before-heating holes can be suppressed from being closed after brazing, the bonding area between the corrugated sheet <NUM> and the side base <NUM> can be ensured, and the bonding strength between the corrugated sheet <NUM> and the base <NUM> can thus be suppressed from being decreased.

In addition, according to the method of manufacturing the heat exchanger <NUM> of Embodiment <NUM>, the before-heating hole can be formed within the range from <NUM> to L - processing tolerance mm. Thus, while the before-heating holes can be suppressed from being closed after brazing, the bonding area between the corrugated sheet <NUM> and the side base <NUM> can be ensured, and the bonding strength between the corrugated sheet <NUM> and the base <NUM> can thus be suppressed from being decreased.

<FIG> illustrates a method of manufacturing a heat exchanger <NUM> according to Embodiment <NUM>. <FIG> illustrates a bridging header <NUM> when the bridging header <NUM> is viewed in the longitudinal direction. The method of manufacturing the heat exchanger <NUM> of Embodiment <NUM> differs from the method of manufacturing the heat exchanger of Embodiment <NUM> in that a corrugated sheet <NUM> has a before-heating hole <NUM> having a rectangular shape as <FIG> illustrates. In Embodiment <NUM>, by the same parts as the parts of Embodiment <NUM> being denoted by the same references, the description thereof will be omitted, and differences from Embodiment <NUM> will be mainly described.

As <FIG> illustrates, in Embodiment <NUM>, the before-heating hole <NUM> has a rectangular shape. Note that, although, in <FIG>, the bridging header <NUM> is disposed so that the side bases <NUM> are positioned above and below across the corrugated sheet <NUM>, the orientation of the bridging header <NUM> is not limited during brazing in the method of manufacturing the heat exchanger <NUM> of Embodiment <NUM>. In most cases, in brazing, a molten brazing material forms a fillet along the outer edge of the before-heating hole <NUM> so as to fill the before-heating hole <NUM> with a contact point between the outer edge of the before-heating hole <NUM> and the side base <NUM> being a starting point. Typically, when a molten metal flows into a space between different parts, the smaller the space therebetween is, the more easily the molten metal fills the space due to capillary force. Similarly, the narrower the space between the outer edge of the before-heating hole <NUM> and the side base <NUM> is, the more the brazing material fills the before-heating hole <NUM>; thus, the before-heating hole <NUM> is likely to be closed.

For example, as the broken line in <FIG> illustrates, when the before-heating hole has a semicircular shape, the space between the outer edge of the before-heating hole <NUM> and the side base <NUM> reaches a maximum size only at a central portion C of the outer edge of the before-heating hole <NUM>. In contrast thereto, as in Embodiment <NUM>, when the before-heating hole <NUM> has a rectangular shape, the space between the outer edge of the before-heating hole <NUM> and the side base <NUM> reaches a maximum size at any point along a side F, of the outer edge of the before-heating hole <NUM>, facing the inner surface of the side base <NUM>. Thus, regarding the case of the rectangular before-heating hole <NUM>, the space between the before-heating hole <NUM> and the side base <NUM> can be widened as a whole compared with the case of the semicircular before-heating hole when the width of the before-heating hole <NUM> is the same in both the cases, and the maximum space between the before-heating hole <NUM> and the side base <NUM> is the same between both the cases.

Note that, where L is a dimension of the planar portion <NUM> of the corrugated sheet <NUM>, the width W of the rectangular before-heating hole <NUM> can be within the range from <NUM> to L - processing tolerance mm, as with the diameter of the semicircular before-heating hole <NUM> in Embodiment <NUM>. The processing tolerance is, for example, <NUM>.

According to the method of manufacturing the heat exchanger <NUM> of Embodiment <NUM>, the space between the before-heating hole <NUM> and the side base <NUM> can be widened as a whole by the before-heating hole <NUM> being formed into a rectangular shape. Thus, while the before-heating hole <NUM> can be suppressed from being closed after brazing, the bonding area between the corrugated sheet <NUM> and the side base <NUM> can be ensured, and the bonding strength between the corrugated sheet <NUM> and the base <NUM> can thus be suppressed from being decreased.

<FIG> is a perspective view of a bridging header <NUM> according to Embodiment <NUM>. <FIG> is a perspective view of the bridging header <NUM> according to Embodiment <NUM>. Note that, in <FIG>, a covering plate <NUM> is transparent, and the corrugated sheet <NUM> is semitransparent. <FIG> is a perspective view of a base <NUM> according to Embodiment <NUM>. Embodiment <NUM> differs from Embodiment <NUM> in that the base <NUM> has a cutout <NUM> as <FIG> illustrate. In Embodiment <NUM>, by the same parts as the parts of Embodiment <NUM> being denoted by the same references, the description thereof will be omitted, and differences from Embodiment <NUM> will be mainly described.

A heat exchanger <NUM> of Embodiment <NUM> is provided in the outdoor unit <NUM> so that, for example, a bottom base <NUM> serves as the lower side of the base <NUM>. As <FIG> illustrate, a side base <NUM> of Embodiment <NUM> has the cutouts <NUM> having a semicircular shape on both sides of each of the claw portions <NUM>. The depth of each of the cutouts <NUM> is adjusted so that a lower end portion of the cutout <NUM> is positioned below the upper surface of the covering plate <NUM>.

In most cases, during brazing, when the upper surface of the covering plate <NUM> is provided at a position below the upper end face of the side base <NUM>, rainwater, for example, that has showered down on the upper surface of the covering plate <NUM> is obstructed by the side base <NUM>, thereby not being drained; thus, such rainwater may remain thereon to be accumulated. In this case, the water retained on the upper surface of the covering plate <NUM> may corrode the bridging header <NUM>. In contrast thereto, in Embodiment <NUM>, the provided cutouts <NUM> help to remove the retained water and suppress the bridging header <NUM> from being corroded.

Alternatively, when the side base <NUM> is provided at a position lower than the upper surface of the covering plate <NUM> throughout the length of the side base <NUM> for placing priority on drainage, the contact surface between the base <NUM> and the covering plate <NUM> cannot be sufficiently ensured, and insufficient brazing may be caused. In this case, the pressure resistance of the bridging header <NUM> may be decreased. In contrast thereto, in Embodiment <NUM>, the cutouts <NUM> are provided only beside both sides of the claw portion <NUM>, and the pressure resistance and the drainage properties of the bridging header <NUM> can thereby be compatible with one another.

Furthermore, each of the plural claw portions <NUM> of the side base <NUM> is bent at the base thereof for pressing the covering plate <NUM> toward the corrugated sheet <NUM>. At this point, the bending workability of the claw portion <NUM> is improved by the cutouts <NUM> being provided beside both sides of the claw portions <NUM>.

In addition, the side base <NUM> has plural plate-catching portions <NUM>. On both end portions, in the longitudinal direction, of the side base <NUM>, two plate-catching portions <NUM> are provided per end portion and protrude from the inner wall surface of the side base <NUM>. In addition, the bottom base <NUM> has no plate hole into which an end plate <NUM> is fitted. In Embodiment <NUM>, the end plate <NUM> is fixed by an end of the end plate <NUM> being held between the two plate-catching portions <NUM>. In this case also, regarding the bridging header <NUM>, the end plate <NUM> can be fixed while a pressure resistance on per with the pressure resistance when the end plate <NUM> is fitted into the plate hole <NUM> of Embodiment <NUM> is ensured.

The above-described embodiments and modifications may be appropriately combined with one another without departing from the spirit of the present disclosure. For example, the plate-catching portion <NUM> of Embodiment <NUM> may be provided for the base <NUM> of Embodiment <NUM> as a substitute for a part of the base <NUM> or as an additional part to the base <NUM>. In addition, the cutout <NUM> of Embodiment <NUM> may be formed in the base of any one of Embodiments <NUM> to <NUM>.

Claim 1:
A heat exchanger (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) comprising:
a heat transfer tube group (<NUM>) made up of a plurality of heat transfer tubes (<NUM>) each of which has, inside the heat transfer tube, a flow passage through which refrigerant flows, the plurality of heat transfer tubes (<NUM>) that are arranged in a lateral direction being arranged in a longitudinal direction so as to form a plurality of rows;
a fin (<NUM>) provided on the heat transfer tubes (<NUM>) and facilitating heat exchange between refrigerant flowing inside the heat transfer tubes (<NUM>) and air; and
a bridging header (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) into which end portions of the heat transfer tubes (<NUM>) are inserted and that causes refrigerant to flow between the heat transfer tubes (<NUM>) arranged in a lateral direction of the heat transfer tube group (<NUM>),
wherein the bridging header (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) has:
a base (<NUM>,<NUM>,<NUM>) having a flat plate shape and having insertion holes (<NUM>), into which respective ones of end portions of the plurality of heat transfer tubes (<NUM>) are inserted;
a corrugated sheet (<NUM>,<NUM>,<NUM>,<NUM>) being a plate having a shape of a wave in which crest portions (<NUM>) and valley portions (<NUM>) are continuously formed, characterised by each of the crest portions (<NUM>) being provided so as to cover a pair of the insertion holes (<NUM>) arranged in a lateral direction, the valley portions (<NUM>) being in contact with the base (<NUM>,<NUM>,<NUM>) on both sides of each of the insertion holes (<NUM>) in a longitudinal direction of the base (<NUM>,<NUM>,<NUM>), the corrugated sheet (<NUM>,<NUM>,<NUM>,<NUM>) forming, between the corrugated sheet (<NUM>,<NUM>,<NUM>,<NUM>) and the base (<NUM>,<NUM>,<NUM>), a header flow passage (<NUM>), through which refrigerant flows, for every the heat transfer tubes (<NUM>) arranged in a lateral direction of the heat transfer tube group (<NUM>); and further characterised by
a covering plate (<NUM>,<NUM>) covering the corrugated sheet (<NUM>,<NUM>,<NUM>,<NUM>) and pressing the corrugated sheet (<NUM>,<NUM>,<NUM>,<NUM>) toward the base (<NUM>,<NUM>,<NUM>).