Heat Exchanger

The present invention relates to a heat exchanger.

JP2016-118335A discloses a heat exchanger in which core portions are provided so as to be layered with each other. The core portions have top and bottom header tanks and heat exchange pipes through which heat transfer medium flows between the top and bottom header tanks.

Partition portions are provided in the header tanks, and by the heat exchange pipes, lower passes for allowing the heat transfer medium to flow from the top header tank towards the bottom header tank and upper passes for allowing the heat transfer medium to flow from the bottom header tank towards the top header tank are formed in the core portions.

However, with this heat exchanger, the lower passes for allowing the heat transfer medium to flow downwards and the upper passes for allowing the heat transfer medium to flow upwards are provided in an alternate manner. Therefore, when the heat exchange is to be performed by condensing the heat transfer medium in the heat exchange pipes of the core portions, the heat transfer medium having an increased density needs to be pushed up several times in the heat exchange pipes, and so, the flow of the heat transfer medium is deteriorated in efficiency.

An object of the present invention is to provide a heat exchanger capable of facilitating flow of a heat transfer medium.

According to an aspect of the present invention, a heat exchanger configured to heat air by condensing a heat transfer medium undergoing a phase change between a liquid phase and a gaseous phase, the heat exchanger includes a plurality of core portions provided such that the plurality of core portions are overlapped with each other in a flow direction of the air and such that the heat transfer medium flows continuously, the core portions each comprising: an upper header tank to which the heat transfer medium is supplied; a lower header tank arranged below the upper header tank; and a plurality of tubes configured to connect the upper header tank and the lower header tank, the plurality of tubes being configured to perform heat exchange between the heat transfer medium flowing inside the tubes and the air flowing around the tubes, and a communication passage configured to allow communication between the lower header tank of a first core portion of the core portions and the upper header tank of a second core portion of the core portions and to allow the heat transfer medium to flow from the lower header tank to the upper header tank, the second core portion being arranged so as to be overlapped with the first core portion in the flow direction of the air.

In the heat exchanger of the above aspect, a heat transfer medium that has been supplied to a first core portion flows from an upper header tank of the core portion towards the lower header tank side through tubes. The heat transfer medium in the lower header tank of the first core portion is supplied to a second core portion through a communication passage. The heat transfer medium that has been supplied to the second core portion flows from the upper header tank of the core portion towards the lower header tank through the tubes.

Therefore, it is possible to allow the heat transfer medium, whose density has been increased by being condensed as the heat transfer medium flows towards the downstream side, to flow from the upper side to the lower side in the tubes of both core portions that communicate with each other via the communication passage. With such a configuration, there is no need to cause the heat transfer medium, whose density has been increased by being condensed, to flow upward from the lower side to the upper side in the tubes of the core portions. Therefore, according to the present invention, the heat exchanger capable of facilitating the flow of the heat transfer medium.

In the following, a heat exchangeraccording to embodiments of the present invention will be described with reference to the drawings.

An overall configuration of the heat exchangerwill be described first with reference to.is a perspective view of the heat exchangeraccording to the embodiment of the present invention.

The heat exchangeris installed in a vehicle (not shown). The heat exchangerperforms a heat exchange between air that is used for air-conditioning and a heat transfer medium that is circulated in an air-conditioning device (not shown) and that undergoes a phase change between a liquid phase and a gaseous phase.

Specifically, the heat exchangeris provided in an HVAC (a Heating Ventilation and Air Conditioning) unit (not shown) through which the air used for the air-conditioning passes. The heat exchangeris a condenser that, when the air-conditioning device performs a cabin-heating operation, performs the heat exchange with the air used for the air-conditioning to heat the air by condensing the heat transfer medium.

The heat exchangerhas: an upstream-side core portionserving as a first core portion to which the heat transfer medium is supplied; a downstream-side core portionserving as a second core portion to which the heat transfer medium from the upstream-side core portionis supplied; and reinforcing membersthat are respectively provided on both side portions of the heat exchanger.

The downstream-side core portionand the upstream-side core portionare arranged so as to be overlapped with each other in the air-flow direction. The downstream-side core portionis arranged on the windward side. The upstream-side core portionis arranged on the downwind side.

In this embodiment, although a case in which the heat exchangeris configured of two core portions, the downstream-side core portionand the upstream-side core portion, will be described, this embodiment is not limited thereto. The heat exchangermay be configured of three or more core portions. In addition, the upstream-side core portionand the downstream-side core portionrepresent a first core portion and a second core portion, respectively, among a set of core portions that are arranged along the flow direction of the heat transfer medium in a consecutive manner.

The downstream-side core portionand the upstream-side core portionrespectively have upper header tanksA,B to which the heat transfer medium is supplied and lower header tanksA,B that are arranged below the upper header tanksA,B. The downstream-side core portionhas a plurality of fins (not shown) and a plurality of tubesthat connect the upper header tankA and the lower header tankA and that perform the heat exchange between the heat transfer medium that flows inside the tubesand the air that flows around the tubes. In addition, the upstream-side core portionhas a plurality of fins (not shown) and a plurality of tubesthat connect the upper header tankB and the lower header tankB and that perform the heat exchange between the heat transfer medium that flows inside the tubesand the air that flows around the tubes.

Each header tankA,B,A,B, the tubes, and the fins are made of a metal such as aluminum and are integrally joined to each other by brazing, etc.

In addition, the heat exchangerhas a communication passagethat allows communication between the lower header tankB of the upstream-side core portionand the upper header tankA of the downstream-side core portion.

The tubesprovided on each of the core portionsandrespectively connect the header tanksA,B,A,B of the respective core portionsandwith each other and perform the heat exchange between the heat transfer medium that flows inside the tubesand the air that flows around the tubes.

The respective core portionsandare provided so as to intersect with the air-flow directionsuch that the air can flow between the respective tubes. The respective core portionsandare provided so as to be overlapped with each other in the air-flow directionsuch that the air can flow through in a consecutive manner.

The plurality of tubesare arranged side by side in parallel, thereby being layered with interval gaps. The tubesare each formed to have a flat shape and are layered in the thickness direction. The fins are provided between adjacent tubes. The tubesare layered in the direction that intersects with the air-flow direction. Each of the tubesis formed with an inner flow passage through which the heat transfer medium flows.

The fins are provided between the adjacent tubes, and are layered alternately with the tubes. The fins are formed to have a wave-like shape along the longitudinal direction of the tubesand are joined to two adjacent tubes. The air supplied by a blower (not shown) of the air-conditioning device flows around the plurality of tubesand the fins. Therefore, the heat transfer medium that flows inside the tubescan undergo the heat exchange with the air via surfaces of the tubesand the fins. As described above, the fins promote the heat exchange between the heat transfer medium and the air.

The reinforcing membersare respectively provided on both side portions of the downstream-side core portionand the upstream-side core portion. The reinforcing membersare in contact with the fins that are provided on both side portions of the downstream-side core portionand the upstream-side core portion. End portions of the reinforcing membersin the longitudinal direction are respectively engaged with the header tanksA,B,A,B, thereby linking and reinforcing between pairs of header tanksA,B,A,B. When the tubesand the fins are brazed to form the downstream-side core portionand the upstream-side core portion, the reinforcing membersare integrated with the downstream-side core portionand the upstream-side core portionby being brazed to the fins.

The header tanksA,B,A, andB each has a tubular shape elongated in the arrangement direction of the tubes. The header tanksA,B,A, andB each has a closed cross-sectional shape. In a state in which the heat exchangeris attached, an upper surface of each of the upper header tanksA andB is formed to have a curved shape in which the center portion in the width direction is projected upwards. The respective end portions of the respective header tanksA,B,A, andB have substantially the same shape.

The upper header tanksA andB and the lower header tanksA andB of the respective core portionsandare arranged so as to face each other. The respective end portions of the plurality of tubesin the longitudinal direction are inserted into and joined to the upper header tanksA andB and the lower header tanksA andB that are arranged so as to face each other. Each of the header tanksA,B,A,B temporarily stores the heat transfer medium.

A first end of the upper header tankB of the upstream-side core portionforms a heat transfer medium inlet, through which the heat transfer medium enters. A supply pipethat supplies the heat transfer medium is connected to the heat transfer medium inlet. In other words, the upstream-side core portionhas the heat transfer medium inlet, through which the heat transfer medium enters, on a first-side end portion on a first-side-portion side.

A second end of the upper header tankB of the upstream-side core portionis closed. The heat transfer medium that has entered the upper header tankB of the upstream-side core portionflows to the lower header tankB through the respective tubes. The heat transfer medium performs the heat exchange with the air while flowing through the tubes.

A first end of the lower header tankB of the upstream-side core portionis closed. A second end of the lower header tankB of the upstream-side core portionforms a heat transfer medium outletthrough which the heat transfer medium flows out. The above-described communication passageis connected to the heat transfer medium outlet.

A second end of the upper header tankA of the downstream-side core portionforms a heat transfer medium inletthrough which the heat transfer medium enters. The above-described communication passageis connected to the heat transfer medium inlet.

With such a configuration, the communication passageallows the communication between the upstream-side core portionand the downstream-side core portionat a second-side end portion of the upstream-side core portionon a second-side-portion side. Specifically, the communication passageallows the heat transfer medium that flows out from a second end portion of the lower header tankB of the upstream-side core portionto flow to a second end portion of the upper header tankA of the downstream-side core portion.

A first end of the upper header tankA of the downstream-side core portionis closed. The heat transfer medium that has entered the upper header tankA of the downstream-side core portionflows to the lower header tankA through the respective tubes. The heat transfer medium performs the heat exchange with the air while flowing through the tubes.

A second end of the lower header tankA of the downstream-side core portionis closed. A first end of the lower header tankA of the downstream-side core portionforms a heat transfer medium outletthrough which the heat transfer medium flows out. A recovery pipethat recovers the heat transfer medium is connected to the heat transfer medium outlet.

is an exploded perspective view showing the structure of the communication passage.

As shown in, the communication passageis formed of a lower connector, an upper connector, and a tube memberthat allows the communication between the lower connectorand the upper connector. The inner cross-sectional area of the tube memberis sufficiently larger than the inner cross-sectional area of the tubes.

The lower connectoris connected to the lower header tankB of the upstream-side core portionso as to be communicable. The upper connectoris connected to the upper header tankA of the downstream-side core portionso as to be communicable.

The one end of the tube memberis connected to a connection holethat is formed in the lower connectorand the other end of the tube memberis connected to a connection hole (not shown) that is formed in the upper connector. The tube memberallows the communication between the lower connectorand the upper connector.

In a state in which the lower connectoris connected to the corresponding lower header tankB and the upper connectoris connected to the corresponding upper header tankA, the connection holeof the lower connectorand the connection hole (not shown) of the upper connector, to which the tube memberis connected, face each other. In addition, the connection holeof the lower connectorand the connection hole (not shown) of the upper connectoropen in the same direction as the extending direction of the tubes(see) extending in the vertical direction.

is a sectional view taken along a line III-III in.

As shown in, the lower connectorand the upper connectorare each formed of a blockformed as the same member.

The blockforming each of the lower connectorand the upper connectorhas a flat surfacethat is arranged so as to face each of the core portionsand. In addition, the blockhas a ridge-like projected portionthat projects to the opposite side of the surface. With such a configuration, the blockis formed to have a triangular prism shape.

The surfaceof the blockhas a first insertion holeand a second insertion holeinto which the respective end portions of the upper header tanksA andB, which are arranged so as to be overlapped with each other, or the respective end portions of the lower header tanksA andB, which are arranged so as to be overlapped with each other, can be respectively inserted. The first insertion holeand the second insertion holehave substantially the same shape as the respective end portions of the respective header tanksA,B,A, andB. In addition, the first insertion holeand the second insertion holeare arranged at the same interval as the arrangement interval of the respective header tanksA,B,A,B, which are arranged so as to be overlapped with each other.

An innermost portion of the second insertion holeis closed by a closing surface. With such a configuration, the second insertion holeforms a closing portionthat closes the end portion of the header tank to be inserted.

The blockhas the above-described connection hole, which communicates with the first insertion hole, in an end surface(see) serving as an intersecting surface that extends in the direction orthogonal to the extending direction of the surface. The first insertion holehas, on the innermost side thereof, an innermost surfacethat is in parallel with the surface. An inner passagethat communicates with the connection holeis opened in the innermost surface.

The connection holeis opened perpendicularly to the end surface(see) and extends parallel to the surface. The connection holeis positioned at the midpoint between the center line Cthat extends through the center of the first insertion holeand the center line Cthat extends through the center of the second insertion hole(see). In other words, the first insertion holeand the second insertion holeare arranged at the positions symmetrical with respect to the connection hole.

With such a configuration, by arranging the end surface, in which the connection holeis opened, so as to face upwards, it is possible to utilize the blockas the lower connector. In addition, by arranging the end surface, in which the connection holeis opened, so as to face downwards, it is possible to utilize the blockas the upper connector.

As shown in, the end portion of the lower header tankB of the upstream-side core portionis inserted into the first insertion holeof the blockforming the lower connector, and thereby, the lower header tankB is made to communicate with the connection hole. In addition, the end portion of the lower header tankA of the downstream-side core portionis inserted into the second insertion hole, and thereby, the end portion of the lower header tankA is closed.

Next, the end portion of the upper header tankB of the upstream-side core portionis inserted into the second insertion holeof the blockforming the upper connector, and thereby, the end portion of the upper header tankB is closed. In addition, the end portion of the upper header tankA of the downstream-side core portionis inserted into the first insertion hole, and thereby, the upper header tankA is made to communicate with the connection hole.

The connection holeis arranged at the midpoint between the center line Cthat extends through the center of the first insertion holeand the center line Cthat extends through the center of the second insertion hole(see). Therefore, the connection holeof the lower connectorthat is formed of the block, which is arranged such that the end surfacefaces upwards, and the connection holeof the upper connectorthat is formed of the block, which is arranged such that the end surfacefaces downwards, face each other.

In addition, the connection holeis opened perpendicularly to the end surfaceand extends parallel to the surface. Therefore, the opening direction of the connection holeof the lower connectorand the opening direction of the connection holeof the upper connectorcoincide with the extending direction of the tubesextending in the vertical direction.

As shown in, the inner passagethat allows the communication between the first insertion holeand the connection holeextends linearly in the direction at an oblique angle of 40 degrees with respect to the innermost surfaceof the first insertion hole. The inner passageis formed, for example, by machining using a drill.