US20070051504A1

US20070051504A1 - Heat exchanger

Info

Publication number: US20070051504A1
Application number: US11/515,872
Authority: US
Inventors: Hideo Ohashi
Original assignee: Showa Denko KK
Current assignee: Resonac Holdings Corp
Priority date: 2005-09-06
Filing date: 2006-09-06
Publication date: 2007-03-08

Abstract

A heat exchanger used as an evaporator includes a refrigerant inlet header section and a refrigerant outlet header section. The refrigerant inlet and outlet header sections each include a header section body having opened opposite ends and two caps closing opposite end openings of the header section body. The header section body of the refrigerant inlet header section and the header section body of the refrigerant outlet header section are integral with each other. The caps are fitted into the corresponding opposite end openings of the header section bodies. Projections formed at peripheral portions of the caps are fitted into corresponding mating holes formed in tubular walls of the header section bodies. In this condition, the caps are joined to the header section bodies. This heat exchanger allows relatively easy practice of the work of preventing detachment of caps in manufacture thereof.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a heat exchanger preferably used as an evaporator of a car air conditioner, which is a refrigeration cycle to be mounted on, for example, an automobile.
Herein and in the appended claims, the left-hand and right-hand sides of FIG. 2 will be referred to as “left” and “right,” respectively.
Conventionally, a so-called laminated evaporator has been widely employed as an evaporator for use in a car air conditioner. In the laminated evaporator, a plurality of flat, hollow members, each of which includes a pair of depressed plates facing each other and brazed to each other at their peripheral edge portions, are arranged in parallel, and corrugate fins are each disposed between and brazed to the adjacent flat, hollow members.
However, in recent years, evaporators have been demanded to further reduce size and weight and to exhibit higher performance. The present applicant proposed a heat exchanger for use in an evaporator which fulfills those requirements (refer to Japanese Patent Application Laid-Open (Kokai) No. 2005-164226). The proposed heat exchanger includes a heat exchange core section, a first header section, a second header section, a third header section, and a fourth header section. The heat exchange core section includes a plurality of rows of heat exchange tube groups arranged in an air flow direction, each heat exchange tube group consisting of a plurality of heat exchange tubes arranged in a left-right direction at predetermined intervals, and a plurality of fins disposed between and joined to the adjacent heat exchange tubes. The first header section is disposed on a first-end side of the heat exchange tubes, and the heat exchange tubes of at least a single heat exchange tube group are connected thereto. The second header section is disposed on the first-end side of the heat exchange tubes and upstream of the first header section with-respect to the air flow direction, and the heat exchange tubes of the remaining heat exchange tube group(s) are connected thereto. The third header section is disposed on a second-end side of the heat exchange tubes, and the heat exchange tubes connected to the first header section are connected thereto. The fourth header section is disposed on the second-end side of the heat exchange tubes, and the heat exchange tubes connected to the second header section are connected thereto. Each of the first to fourth header sections includes a hollow header section body whose opposite ends are open, and two caps closing corresponding opposite end openings of the header section body. The header section body of the first header section and the header section body of the second header section are integral with each other, and the header section body of the third header section and the header section body of the fourth header section are integral with each other. The two caps which close the openings on one side of the header section bodies of the first header section and the second header section are integrated with each other to form a closing member, and the two caps which close the openings on the other side of the header section bodies of the first header section and the second header section are integrated with each other to form a closing member. The two caps which close the openings on one side of the header section bodies of the third header section and the fourth header section are integrated with each other to form a closing member, and the two caps which close the openings on the other side of the header section bodies of the third header section and the fourth header section are integrated with each other to form a closing member.
The heat exchanger disclosed in the above publication is manufactured through steps of assembling and provisionally joining the respective constituent members, and brazing all the constituent members together. Specifically, this heat exchanger is manufactured through steps of arranging the heat exchange tubes, the corrugate fins, and the header section bodies in an assembled condition; provisionally joining the constituent members, while the closing members each being composed of two caps integrated with each other are fitted to opposite end portions of the header section bodies of the first and second header sections and to opposite end portions of the third and fourth header sections; and simultaneously brazing the heat exchange tubes and the corrugate fins together, the heat exchange tubes and the header section bodies together, and the header section bodies and the caps together.
However, in some cases, in manufacture of the heat exchanger disclosed in the above publication, provisionally fixing the closing members; i.e., the caps, to the header section bodies in such a manner that the caps are not detached may become troublesome.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above problem and to provide a heat exchanger which allows relatively easy practice of the work of preventing detachment of caps in manufacture thereof.
To achieve the above object, the present invention comprises the following modes.
1) A heat exchanger comprising two header sections spaced apart from each other and a plurality of heat exchange tubes extending between the two header sections and arranged at predetermined intervals in a longitudinal direction of the two header sections with opposite end portions thereof connected to the two header sections, the two header sections each comprising a hollow header section body having opened opposite ends, and two caps closing opposite end openings of the header section body wherein the caps are fitted into the corresponding opposite end openings of the header section bodies; a projection is formed at a peripheral portion of each of the caps; a mating hole into which the projection of the cap is fitted is formed in a tubular wall of each of the header section bodies; and while the projections of the caps are fitted into the corresponding mating holes of the header section bodies, the caps are joined to the header section bodies.
2) A heat exchanger according to par. 1), wherein the header section bodies each comprise a first member which forms a portion of the header section body on a side toward the heat exchange tubes and to which the heat exchange tubes are connected, and a second member which forms the remaining portion of the header section body and is joined to the first member, and the mating holes into which the corresponding projections of the caps are fitted are formed in the first and second members.
3) A heat exchanger comprising:
a heat exchange core section comprising:

- a plurality of rows of heat exchange tube groups arranged in an air flow direction, each heat exchange tube group consisting of a plurality of heat exchange tubes arranged in a left-right direction at predetermined intervals; and
- a plurality of fins disposed between and joined to the adjacent heat exchange tubes;

a first header section which is disposed on a first-end side of the heat exchange tubes and to which the heat exchange tubes of at least a single heat exchange tube group are connected;
a second header section which is disposed on the first-end side of the heat exchange tubes and upstream of the first header section with respect to the air flow direction and to which the heat exchange tubes of the remaining heat exchange tube group(s) are connected;
a third header section which is disposed on a second-end side of the heat exchange tubes and to which the heat exchange tubes connected to the first header section are connected; and
a fourth header section which is disposed on the second-end side of the heat exchange tubes and to which the heat exchange tubes connected to the second header section are connected;
the first to fourth header sections each comprising a hollow header section body having opened opposite ends, and two caps closing opposite end openings of the header section body,
the header section body of the first header section and the header section body of the second header section being integral with each other, and the header section body of the third header section and the header section body of the fourth header section being integral with each other,
wherein the caps are fitted into the corresponding opposite end openings of the header section bodies; a projection is formed at a peripheral portion of each of the caps; a mating hole into which the projection of the cap is fitted is formed in a tubular wall of each of the header section bodies; and while the projections of the caps are fitted into the corresponding mating holes of the header section bodies, the caps are joined to the header section bodies.
4) A heat exchanger according to par. 3), wherein the header section body of the first header section and the header section body of the second header section are formed by a first member which forms portions of the header section bodies on a side toward the heat exchange tubes and to which the heat exchange tubes are connected, and a second member which forms the remaining portions of the header section bodies and is joined to the first member, and
the mating holes into which the corresponding projections of the caps are fitted are formed in the first and second members.
5) A heat exchanger according to par. 4), wherein the two caps which close one end opening of the header section body of the first header section and one end opening of the header section body of the second header section, respectively, are integral with each other, and the two caps which close the other end opening of the header section body of the first header section and the other end opening of the header section body of the second header section, respectively, are integral with each other.
6) A heat exchanger according to par. 3), wherein the header section body of the third header section and the header section body of the fourth header section are formed by a first member which forms portions of the header section bodies on a side toward the heat exchange tubes and to which the heat exchange tubes are connected, and a second member which forms the remaining portions of the header section bodies and is joined to the first member, and
the mating holes into which the corresponding projections of the caps are fitted are formed in the first and second members.
7) A heat exchanger according to par. 6), wherein the two caps which close one end opening of the header section body of the third header section and one end opening of the header section body of the fourth header section, respectively, are integral with each other, and the two caps which close the other end opening of the header section body of the third header section and the other end opening of the header section body of the fourth header section, respectively, are integral with each other.
8) A heat exchanger according to par. 3), wherein a refrigerant inlet is formed on the cap which closes one end opening of the header section body of the first header section; a refrigerant outlet is formed on the cap which closes one end opening of the header section body of the second header section located on the same side as the refrigerant inlet; and the third header section and the fourth header section communicate with each other.
The above-mentioned heat exchanger is preferably used as an evaporator in a refrigeration cycle having a compressor, a refrigerant cooler, and an evaporator. This refrigeration cycle is mounted on a vehicle in the form of, for example, an air conditioner.
In the heat exchanger of par. 1), the caps are fitted into the corresponding opposite end openings of the header section bodies; a projection is formed at a peripheral portion of each of the caps; a mating hole into which the projection of the cap is fitted is formed in a tubular wall of each of the header section bodies; and while the projections of the caps are fitted into the corresponding mating holes of the header section bodies, the caps are joined to the header section bodies. Thus, in manufacture of the heat exchanger, by practicing a relatively easy work of fitting the projections of the caps into the corresponding mating holes of the header section bodies, detachment of the caps from the header section bodies can be reliably prevented. Also, since the caps are fitted into the corresponding opposite end openings of the header section bodies, projection of peripheral portions of the caps to the exterior of the header section bodies can be prevented.
The heat exchanger of par. 2) allows the projections of the caps to be fitted into the corresponding mating holes when the first and second members are assembled together to form individual header section bodies. Thus, the work of attaching the caps to the header section bodies is facilitated.
In the heat exchanger of par. 3), the caps are fitted into the corresponding opposite end openings of the header section bodies; a projection is formed at a peripheral portion of each of the caps; a mating hole into which the projection of the cap is fitted is formed in a tubular wall of each of the header section bodies; and while the projections of the caps are fitted into the corresponding mating holes of the header section bodies, the caps are joined to the header section bodies. Thus, in manufacture of the heat exchanger, by practicing a relatively easy work of fitting the projections of the caps into the corresponding mating holes of the header section bodies, detachment of the caps from the header section bodies can be reliably prevented. Also, since the caps are fitted into the corresponding opposite end openings of the header section bodies, projection of peripheral portions of the caps to the exterior of the header section bodies can be prevented.
The heat exchanger of par. 4) allows the projections of the caps to be fitted into the corresponding mating holes when the first and second members are assembled together to form the header section bodies of the first and second header sections. Thus, the work of attaching the caps to the header section bodies is facilitated.
The heat exchanger of par. 5) implements a reduction in the number of components. In manufacture of the heat exchanger, the work of assembling together the first and second members, which form the header section bodies of the first and second header sections, and the caps, which close the opposite end openings of the two header section bodies, is facilitated.
The heat exchanger of par. 6) allows the projections of the caps to be fitted into the corresponding mating holes when the first and second members are assembled together to form the header section bodies of the third and fourth header sections. Thus, the work of attaching the caps to the header section bodies is facilitated.
The heat exchanger of par. 7) implements a reduction in the number of components. In manufacture of the heat exchanger, the work of assembling together the first and second members, which form the header section bodies of the third and fourth header sections, and the caps, which close the opposite end openings of the two header section bodies, is facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially cut-away perspective view showing the overall configuration of an evaporator of Embodiment 1 to which a heat exchanger according to the present invention is applied;
FIG. 2 is a fragmentary view in vertical section showing the evaporator of FIG. 1 with its intermediate portion omitted;
FIG. 3 is an exploded perspective view of a refrigerant inlet/outlet tank of the evaporator of FIG. 1;
FIG. 4 is an enlarged fragmentary view in section taken along line A-A of FIG. 2;
FIG. 5 is an enlarged fragmentary view in section taken along line B-B of FIG. 2;
FIG. 6 is an enlarged fragmentary view in section taken along line C-C of FIG. 2;
FIG. 7A is an exploded perspective view showing, on an enlarged scale, a portion of the refrigerant inlet/outlet tank of the evaporator of FIG. 1;
FIG. 7B is a perspective view showing, on an enlarged scale, a portion of the refrigerant inlet/outlet tank of the evaporator of FIG. 1;
FIG. 8 is an exploded perspective view of a refrigerant turn tank of the evaporator of FIG. 1;
FIG. 9A is an exploded perspective view showing, on an enlarged scale, a portion of the refrigerant turn tank of the evaporator of FIG. 1;
FIG. 9B is a perspective view showing, on an enlarged scale, a portion of the refrigerant turn tank of the evaporator of FIG. 1;
FIG. 10 is a diagram showing the flow of a refrigerant in the evaporator of FIG. 1;
FIG. 11A is an exploded perspective view showing, on an enlarged scale, a portion of a refrigerant inlet/outlet tank of an evaporator of Embodiment 2 to which a heat exchanger according to the present invention is applied;
FIG. 11B is a perspective view showing, on an enlarged scale, a portion of the refrigerant inlet/outlet tank of the evaporator of Embodiment 2;
FIG. 12A is an exploded perspective view showing, on an enlarged scale, a portion of a refrigerant turn tank of the evaporator of Embodiment 2; and
FIG. 12B is a perspective view showing, on an enlarged scale, a portion of the refrigerant turn tank of the evaporator of Embodiment 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will next be described in detail with reference to the drawings. In the drawings, like sections or components throughout the several views are denoted by like reference numerals, and repeated description thereof is omitted.
Herein, the term “aluminum” encompasses aluminum alloys in addition to pure aluminum. Also, the downstream side (a direction represented by arrow X in FIG. 1; the right side of FIG. 4) of an air flow through air passing clearances between adjacent heat exchange tubes will be referred to as,the “front,” and the opposite side as the “rear.” The upper and lower sides of FIG. 1 will be referred to as “upper” and “lower,” respectively.
Embodiment 1:
The present embodiment is shown in FIGS. 1 to 10.
FIGS. 1 and 2 show the overall configuration of an evaporator for a car air conditioner to which the present invention is applied. FIGS. 3 to 9 show the configuration of essential portions of the evaporator. FIG. 10 shows how a refrigerant flows in the evaporator.
In FIGS. 1 and 2, the evaporator 1, which is used in a car air conditioner using a chlorofluorocarbon-based refrigerant, includes a refrigerant inlet/outlet tank 2 made of aluminum and a refrigerant turn tank 3 made of aluminum, the tanks 2 and 3 being vertically spaced apart from each other, and further includes a heat exchange core section 4 provided between the tanks 2 and 3.
The refrigerant inlet/outlet tank 2 includes a refrigerant inlet header section 5 (first header section) located on a side toward the front (downstream side with respect to the air flow direction) and a refrigerant outlet header section 6 (second header section) located on a side toward the rear (upstream side with respect to the air flow direction). The refrigerant inlet header section 5 and the refrigerant outlet header section 6 are integral with each other via a connection means, which will be described later. A refrigerant inlet pipe 7 made of aluminum is connected to the refrigerant inlet header section 5 of the refrigerant inlet/outlet tank 2. A refrigerant outlet pipe 8 made of aluminum is connected to the refrigerant outlet header section 6. The refrigerant turn tank 3 includes a refrigerant inflow header section 9 (third header section) located on the side toward the front and a refrigerant outflow header section 11 (fourth header section) located on the side toward the rear. The refrigerant inflow header section 9 and the refrigerant outflow header section 11 are integral with each other via a connection means, which will be described later.
The heat exchange core section 4 is configured such that heat exchange tube groups 13 are arranged in a plurality of; herein, two, rows in the front-rear direction, each heat exchange tube group 13 consisting of a plurality of heat exchange tubes 12 arranged in parallel at predetermined intervals in the left-right direction. Corrugate fins 14 are disposed within corresponding air-passing clearances between the adjacent heat exchange tubes 12 of the heat exchange tube groups 13 and on the outer sides of the leftmost and rightmost heat exchange tubes 12 of the heat exchange tube groups 13, and are brazed to the corresponding heat exchange tubes 12. Side plates 15 made of aluminum are disposed on the outer sides of the leftmost and rightmost corrugate fins 14, and are brazed to the corresponding corrugate fins 14. The upper and lower ends of the heat exchange tubes 12 of the front heat exchange tube group 13 are connected to the refrigerant inlet header section 5 and the refrigerant inflow header section 9, respectively. The upper and lower ends of the heat exchange tubes 12 of the rear heat exchange tube group 13 are connected to the refrigerant outlet header section 6 and the refrigerant outflow header section 11, respectively.
As shown in FIGS. 3 to 7, the refrigerant inlet/outlet tank 2 includes a plate-like first member 16 which is formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof and to which the heat exchange tubes 12 are connected, and a second member 17 which is formed from a bare aluminum extrudate and covers the upper side of the first member 16.
The first member 16 has front and rear curved portions 22, whose central regions each have an arcuate cross section projecting downward and having a small curvature. Rectangular mating holes 32 into which projections 41 and 42 of caps 18 a, 18 b, 19 a, and 19 b, which will be described later, are formed at left and right end portions of the curved portions 22. A plurality of tube insertion holes 23, which are elongated in the front-rear direction, are formed in the curved portions 22 at predetermined intervals in the left-right direction. The tube insertion holes 23 of the front curved portion 22 and those of the rear curved portion 22 are identical in position in the left-right direction. A rising wall 22 a is formed integrally with each of the front edge of the front curved portion 22 and the rear edge of the rear curved portion 22, over the entire length of the front and rear edges. A flat portion 24 is formed between the two curved portions 22 of the first member 16 and-serves as means for connecting together the refrigerant inlet header section 5 and the refrigerant outlet header section 6. A plurality of through holes 25 are formed in the flat portion 24 at predetermined intervals in the left-right direction.
The second member 17 has a cross section resembling the letter m, which opens downward, and includes front and rear walls 26 extending in the left-right direction; a vertical, intermediate wall 27 provided at a central region thereof between the front and rear walls 26, extending in the left-right direction, and serving as means for connecting together the refrigerant inlet header section 5 and the refrigerant outlet header section 6; and two generally arcuate connection walls 28 projecting upward and integrally connecting the upper end of the intermediate wall 27 and the upper ends of the front and rear walls 26. Engagement portions 26 a to be engaged with the corresponding rising walls 22 a of the front and rear curved portions 22 of the first member 16 are formed at corresponding lower end portions of the front and rear walls 26. The lower end of the intermediate wall 27 projects downward beyond the lower ends of the front and rear walls 26. A plurality of projections 27 a are integrally formed on the lower end face of the intermediate wall 27 at predetermined intervals in the left-right direction in such a manner as to project downward, and are fitted into corresponding through holes 25 of the first member 16. The projections 27 a are formed by cutting off predetermined portions of the intermediate wall 27. A flow-dividing resistance plate 29 (dividing means) for dividing the interior of the refrigerant outlet header section 6 into an upper space 6 a and an lower space 6 b, integrally connects the engagement portion 26 a of the rear wall 26 of the second member 17 and a lower end portion of the intermediate wall 27 over the entire length thereof. A plurality of refrigerant passage holes 31A and 31B in a through-hole form and elongated in the left-right direction are formed in a rear region, excluding left and right end portions thereof, of the flow-dividing resistance plate 29 at predetermined intervals in the left-right direction. Rectangular mating holes 33 into which the projections 41 and 42 of the caps 18 a, 18 b, 19 a, and 19 b, which will be described later, are formed at left and right end portions of top portions of the connection walls 28.
The front curved portion 22 and the flat portion 24 of the first member 16, and the front wall 26, the intermediate wall 27, and the front connection wall 28 of the second member 17 form a hollow header section body 10, whose left and right ends are opened, of the refrigerant inlet header section 5. The rear curved portion 22 and the flat portion 24 of the first member 16, and the rear wall 26, the intermediate wall 27, and the rear connection wall 28 of the second member 17 form a hollow header section body 20, whose left and right ends are opened, of the refrigerant outlet header section 6. The header section bodies 10 and 20 are integral with each other via connection means composed of the flat portion 24 and the intermediate wall 27.
As shown in FIG. 7, left and right end portions of the engagement portion 26 a of the front wall 26 of the second member 17, which partially forms the header section body 10, are each cut out by a length equal to a wall thickness of the front caps 18 a and 19 a of closing members 18 and 19, which will be described later, so as to allow the front caps 18 a and 19 a to be fitted into the left and right end openings, respectively, of the header section body 10. Reference numeral 34 denotes thus-formed cutouts. Similarly, left and right end portions of the engagement portion 26 a of the rear wall 26 of the second member 17, which partially forms the header section body 20, and left and right end portions of the flow-dividing resistance plate 29 are each cut out by a length equal to a wall thickness of the rear caps 18 b and 19 b of the closing members 18 and 19, which will be described later, so as to allow the rear caps 18 b and 19 b to be fitted into the left and right end openings, respectively, of the header section body 20. Reference numeral 35 denotes thus-formed cutouts. Furthermore, left and right end portions of the intermediate wall 27 are each cut out by a length equal to a wall thickness of connection portions 18 c and 19 c of the closing members 18 and 19, which will be described later, so as to allow the connection portions 18 c and 19 c to be fitted to the intermediate wall 27. Reference numeral 36 denotes thus-formed cutouts.
The left end openings of the header section bodies 10 and 20 are closed by the plate-like left closing member 18 which is formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof. The right end openings of the header section bodies 10 and 20 are closed by the plate-like right closing member 19 which is formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof. A plate-like pipe joint member 21 made of aluminum and elongated in the front-rear direction is brazed to the outer surface of the right closing member 19.
The left closing member 18 is configured such that the front cap 18 a to be fitted into the left end opening of the header section body 10 of the refrigerant inlet header section 5 for closing the left end opening, and the rear cap 18 b to be fitted into the left end opening of the header section body 20 of the refrigerant outlet header section 6 for closing the left end opening are integral with each other via the connection portion 18 c. The connection portion 18 c is fitted to the cutout portion 36 formed at a left end portion of the intermediate wall 27 of the second member 17. The front and rear caps 18 a and 18 b and the connection portion 18 c have the same wall thickness. The projections 41 are formed on the front and rear caps 18a and 18 b and are fitted into the corresponding mating holes 32 and 33 formed in tubular walls of the header section bodies 10 and 20; i.e., in left end portions of the first and second members 16 and 17.
The right closing member 19 has the same outline as that of the left closing member 18 and is configured such that the front cap 19 a to be fitted into the right end opening of the header section body 10 of the refrigerant inlet header section 5 for closing the right end opening, and the rear cap 19 b to be fitted into the right end opening of the header section body 20 of the refrigerant outlet header section 6 for closing the right end opening are integral with each other via the connection portion 19 c. The connection portion 19 c is fitted to the cutout portion 36 formed at a right end portion of the intermediate wall 27 of the second member 17. The front and rear caps 19 a and 19 b and the connection portion 19 c have the same wall thickness. A refrigerant inlet 37 for establishing communication between the interior and the exterior of the refrigerant inlet header section 5 is formed in the front cap 19 a. A refrigerant outlet 38 for establishing communication between the upper space 6 a and the exterior of the refrigerant outlet header section 6 is formed in the rear cap 19 b. The projections 42 are formed on the front and rear caps 19 a and 19 b and are fitted into the corresponding mating holes 32 and 33 formed in tubular walls of the header section bodies 10 and 20; i.e., in right end portions of the first and second members 16 and 17.
The pipe joint member 21 has an integrally formed short, cylindrical refrigerant inflow port 45 communicating with the refrigerant inlet 37 of the front cap 19 a of the right closing member 19, and an integrally formed short, cylindrical refrigerant outflow port 46 communicating with the refrigerant outlet 38 of the rear cap 19 b. A diameter-reduced portion 7 a formed at one end portion of the refrigerant inlet pipe 7 is inserted into and brazed to the refrigerant inflow port 45 of the pipe joint member 21. Similarly, a diameter-reduced portion 8 a formed at one end portion of the refrigerant outlet pipe 8 is inserted into and brazed to the refrigerant outflow port 46 of the pipe joint member 21. A slit 47 extending in the vertical direction is formed on the pipe joint member 21 between the refrigerant inflow port 45 and the refrigerant outflow port 46. Through holes 48 and 49 are formed at the upper and lower ends of the slit 47, respectively, such that the through holes 48 and 49 are connected with the slit 47. Further, a portion of the pipe joint member 21 located above the upper through hole 48 and a portion of the pipe joint member 21 located under the lower through hole 49 are bent such that these portions project leftward to thereby from bent portions 51. These upper and lower bent portions 51 come into engagement with the refrigerant inlet header section 5 and the refrigerant outlet header section 6 at a location therebetween; i.e., the central portions of the first and second members 16 and 17 with respect to the front-rear direction.
The first and second members 16 and 17 of the refrigerant inlet/outlet tank 2, the closing members 18 and 19, and the pipe joint member 21 are brazed together as follows. In assembly of the first and second members 16 and 17, the projections 27 a of the second member 17 are inserted into the corresponding through holes 25 of the first member 16, followed by crimping. As a result, upper end portions of the front and rear rising walls 22 a of the first member 16 come into engagement with the engagement portions 26 a at the lower end portions of the front and rear walls 26 of the second member 17. In the thus-established condition, the first and second members 16 and 17 are brazed together by utilization of the brazing material layers of the first member 16. In attachment of the closing members 18 and 19, the front caps 18 a and 19 a are fitted into the left and right end openings, respectively, of the header section body 10; the rear caps 18 b and 19 b are fitted into the left and right end openings, respectively, of the header section body 20; the connection portions 18 c and 19 c are fitted to the corresponding cutout portions 36 of the intermediate wall 27; and the projections 41 and 42 of the caps 18 a, 18 b, 19 a, and 19 b are fitted into the corresponding mating holes 32 and 33. In the thus-established condition, the closing members 18 and 19 are brazed to the first and second members 16 and 17 by utilization of the brazing material layers thereof. The pipe joint member 21 is brazed to the right closing member 19 by utilization of the brazing material layer of the right closing member 19 in the condition that the upper bent portion 51 is in engagement with the central portion of the second member 17 with respect to the front-rear direction, and the lower bent portion 51 is in engagement with the central portion of the first member 16 with respect to the front-rear direction.
The refrigerant inlet/outlet tank 2 is thus formed. A portion of the refrigerant inlet/outlet tank 2 located forward of the flat portion 24 of the first member 16 and the intermediate wall 27 of the second member 17 serves as the refrigerant inlet header section 5. A portion of the refrigerant inlet/outlet tank 2 located backward of the flat portion 24 of the first member 16 and the intermediate wall 27 of the second member 17 serves as the refrigerant outlet header section 6. The refrigerant inlet header section 5 and the refrigerant outlet header section 6 are integrated with each other. The flow-dividing resistance plate 29 divides the refrigerant outlet header section 6 into the upper and lower spaces 6 a and 6 b. The spaces 6 a and 6 b communicate with each other through the refrigerant passage holes 31A and 31B.
As shown in FIGS. 4, 5, 8, and 9, the refrigerant turn tank 3 includes a plate-like first member 70 which is formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof and to which heat exchange tubes 12 are connected, and a second member 71 which is formed from a bare aluminum extrudate and covers the lower side of the first member 70.
A top face 3 a of the refrigerant turn tank 3 has such an arcuate transverse cross section that a central portion thereof with respect to the front-rear direction serves as a top portion 73 and that the height gradually decreases from the top portion 73 toward the front and rear sides. A plurality of grooves 74 are formed on front and rear portions of the refrigerant turn tank 3 at predetermined intervals along the left-right direction such that they extend from the front and rear sides of the top portion 73 of the top face 3 a to front and rear side surfaces 3 b.
The first member 70 has an arcuate transverse cross section such that a central portion thereof with respect to the front-rear direction projects upward. Downwardly extending walls 70 a are formed integrally with front and rear edges of the first member 70 over the entire length thereof. The upper surface of the first member 70 serves as the top face 3 a of the refrigerant turn tank 3. The outer surfaces of the downwardly extending walls 70 a serve as the front and rear side surfaces 3 b of the refrigerant turn tank 3. A plurality of the grooves 74 are formed at predetermined intervals in the left-right direction on the front and rear portions of the first member 70 in such a manner as to extend from the top portion 73 located at the center with respect to the front-rear direction to the lower ends of the downwardly extending walls 70 a. Tube insertion holes 75 elongated in the front-rear direction are formed in the first member 70 excepting the top portion 73; i.e., in front and rear portions of the first member 70, such that the tube insertion holes 75 are located between the adjacent grooves 74. The front tube insertion holes 75 and the rear tube insertion holes 75 are identical in position in the left-right direction. A plurality of through holes 76 are formed in the top portion 73 of the first member 70 at predetermined intervals in the left-right direction. Rectangular mating holes 60 are formed in left and right end portions of the first member 70 on the front and rear sides of the top portion 73. Projections 63 of the caps 72 a and 72 b, which will be described later, are fitted into the corresponding mating holes 60.
The second member 71 has a transverse cross section-resembling the letter w, which opens upward, and includes front and rear walls 77 curved upward and toward the outside with respect to the front-rear direction and extending in the left-right direction; a vertical intermediate wall 78 provided at a central portion of the second member 71 between the front and rear walls 77, extending in the left-right direction, and serving as connection means for connecting together the refrigerant inflow header section 9 and the refrigerant outflow header section 11; and two connection walls 79 integrally connecting the lower ends of the front and rear walls 77 and the lower end of the intermediate wall 78. The upper end of the intermediate wall 78 projects upward beyond the upper ends of the front and rear walls 77. A plurality of projections 78 a projecting upward and to be fitted into the corresponding through holes 76 of the first member 70 are formed integrally with the upper end of the intermediate wall 78 at predetermined intervals in the left-right direction. Refrigerant passage cutouts 78 b are formed between the adjacent projections 78 a of the intermediate wall 78 in such a manner as to extend from its upper edges. The projections 78 a and the cutouts 78 b are formed by cutting out predetermined portions of the intermediate wall 78. Left and right end portions of the intermediate wall 78 are each cut out by a length equal to a wall thickness of connection portions 72 c of closing members 72, which will be described later, so as to allow the connection portions 72 c to be fitted to the intermediate wall 78. Reference numeral 62 denotes thus-formed cutouts. Rectangular mating holes 61 are formed at left and right end portions of the connection walls 79. The projections 63 of the caps 72 a and 72 b, which will be described later, are fitted into the corresponding mating holes 61.
A front half portion of the first member 70, the front wall 77 of the second member 71, the intermediate wall 78, and the front connection wall 79 form a header section body 55, whose left and right ends are opened, of the refrigerant inflow header section 9. A rear half portion of the first member 70, a rear wall 77 of the second member 71, the intermediate wall 78, and the rear connection wall 79 form a header section body 56, whose left and right ends are opened, of the refrigerant outflow header section 11. The header section bodies 55 and 56 are integral with each other via connection means composed of the top portion 73 and the intermediate wall 78.
The opposite end openings of the header section bodies 55 and 56 are closed by the plate-like closing members 72 formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof. The closing members 72 are each configured such that the front cap 72 a to be fitted into the left/right end opening of the header section body 55 of the refrigerant inflow header section 9 for closing the left/right end opening, and the rear cap 72 b to be fitted into the left/right end opening of the header section body 56 of the refrigerant outflow header section 11 for closing the left/right end opening are integral with each other via the connection portion 72 c. The connection portion 72 c is fitted to the cutout portion 62 formed at a left/right end portion of the intermediate wall 78 of the second member 71. The front and rear caps 72 a and 72 b and the connection portion 72 c have the same wall thickness. The projections 63 are formed on the front and rear caps 72 a and 72 b and are fitted into the corresponding mating holes 60 and 61 formed in tubular walls of the header section bodies 55 and 56; i.e., in left/right end portions of the first and second members 70 and 71.
The first and second members 70 and 71 of the refrigerant return tank 3 and the two closing members 72 are brazed together as follows. In assembly of the first and second members 70 and 71, the projections 78 a of the second member 71 are inserted into the corresponding through holes 76, followed by crimping. As a result, lower end portions of the front and rear downwardly extending walls 70 a of the first member 70 are fitted to corresponding upper end portions of the front and rear walls 77 of the second member 71. In the thus-established condition, the first and second members 70 and 71 are brazed together by utilization of the brazing material layers of the first member 70. In attachment of the two closing members 72, the front caps 72 a are fitted into the left and right end openings of the header section body 55; the rear caps 72 b are fitted into the left and right end openings of the header section body 56; the connection portions 72 c are fitted to the corresponding cutout portions 62; and the projections 63 of the front and rear caps 72 a and 72 b are fitted into the corresponding mating holes 60 and 61. In the thus-established condition, the two closing members 72 are brazed to the first and second members 70 and 71 by utilization of the brazing material layers thereof. The upper end openings of the cutouts 78 b of the intermediate wall 78 of the second member 71 are closed by the first member 70 to thereby form refrigerant passage holes 80.
The refrigerant turn tank 3 is thus formed. A portion of the refrigerant turn tank 3 located forward of the intermediate wall 78 of the second member 71 serves as the refrigerant inflow header section 9. A portion of the refrigerant turn tank 3 located backward of the intermediate wall 78 serves as the refrigerant outflow header section 11. The refrigerant inflow header section 9 and the refrigerant outflow header section 11 communicate with each other via the refrigerant passage holes 80.
Each of the heat exchange tubes 12 which constitute the front and rear heat exchange tube groups 13 of the heat exchange core section 4 is formed from an aluminum extrudate and assumes a flat form having a wide width in the front-rear direction. In the heat exchange tube 12, a plurality of refrigerant channels 12 a extending in the longitudinal direction thereof are formed in parallel therein (see FIG. 6). Upper end portions of the heat exchange tubes 12 are inserted into the corresponding tube insertion holes 23 of the first member 16 of the refrigerant inlet/outlet tank 2 and brazed to the first member 16 by utilization of the brazing material layers of the first member 16. Lower end portions of the heat exchange tubes 12 are inserted into the corresponding tube insertion holes 75 of the first member 70 of the refrigerant turn tank 3 and brazed to the first member 70 by utilization of the brazing material layers of the first member 70.
Preferably, the thickness of the heat exchange tube 12 as measured in the left-right direction; i.e., a tube height, is 0.75 mm to 1.5 mm; the width of the heat exchange tube 12 as measured in the front-rear direction is 12 mm to 18 mm; the wall thickness of the heat exchange tube 12 is 0.175 mm to 0.275 mm; the thickness of a intermediate wall separating the refrigerant channels from each other is 0.175 mm to 0.275 mm; the pitch of the intermediate walls is 0.5 mm to 3.0 mm; and the front and rear end walls each have a radius of curvature of 0.35 mm to 0.75 mm as measured on the outer surface thereof.
In place of use of the heat exchange tube 12 formed from an aluminum extrudate, a heat exchange tube to be used may be formed such that an inner fin is inserted into a seam welded pipe of aluminum so as to form a plurality of refrigerant channels therein. Alternatively, a heat exchange tube to be used may be formed as follows. An aluminum brazing sheet having a brazing material layer on one side thereof is subjected to a rolling process performed on the side where the brazing material is present, so as to form a plate that includes two flat-wall-forming portions connected together via a connection portion; side-wall-forming portions, which are formed, in a bulging condition, integrally with the corresponding flat-wall-forming portions at their side edges located in opposition to the connection portion; and a plurality of partition-wall-forming portions, which are formed integrally with the flat-wall-forming portions in such a manner as to project from the flat-wall-forming portions and to be arranged at predetermined intervals in the width direction of the flat-wall-forming portions. The thus-prepared plate is bent at the connection portion into a hairpin form such that the side-wall-forming portions abut each other, followed by brazing. The partition-wall-forming portions become intermediate walls.
Each of the corrugated fins 14 is made in a wavy form from an aluminum brazing sheet having a brazing material layer over opposite surfaces thereof. The corrugate fin 14 includes wave crest portions, wave trough portions, and connection portions each connecting together the wave crest portion and the wave trough portion. A plurality of louvers are formed at the connection portions in such a manner as to be juxtaposed in the front-rear direction. The front and rear heat exchange tube groups 13 share the corrugate fin 14. The width of the corrugate fin 14 as measured in the front-rear direction is approximately equal to the span between the front edges of the heat exchange tubes 12 of the front heat exchange group 13 and the rear edges of the rear heat exchange tubes 12 of the rear heat exchange tube group 13. The fin height of the corrugate fin 14 means a direct distance between the wave crest portion and the wave through portion, and is preferably 7.0 mm to 10.0 mm. The fin pitch of the corrugate fin 14 means half the distance between the centers in the vertical direction of adjacent wave crest portions or wave through portions, and is preferably 1.3 mm to 1.8 mm. Instead of a single corrugate fin being shared between the front and rear heat exchange tube groups 13, a corrugate fin may be disposed between the adjacent heat exchange tubes 12 of each of the front and rear heat exchange tube groups 13.
In manufacture of the evaporator 1, constituent members thereof excluding the refrigerant inlet pipe 7 and the refrigerant outlet pipe 8 are assembled and provisionally fixed together, and then all the constituent members are brazed together. In assembly of the first and second members 16 and 17 of the refrigerant inlet/outlet tank 2, the closing members 18 and 19 are disposed between the first and second members 16 and 17 such that the projections 41 and 42 of the front and rear caps 18 a, 18 b, 19 a, and 19 b are fitted into the corresponding mating holes 32 and 33. In assembly of the first and second members 70 and 71 of the refrigerant turn tank 3, the two closing members 72 are disposed between the first and second members 70 and 71 such that the projections 63 of the front and rear caps 72 a and 72 b are fitted into the corresponding mating holes 60 and 61. This prevents detachment of the closing members 18, 19, and 72; i.e., detachment of the front and rear caps 18 a, 18 b, 19 a, 19 b, 72 a, and 72 b, which could otherwise result during brazing.
The evaporator 1, together with a compressor, a condenser (refrigerant cooler), and an expansion valve (pressure-reducing device), constitutes a refrigeration cycle which uses a chlorofluorocarbon-based refrigerant. This refrigeration cycle is installed in a vehicle, such as an automobile, as a car air conditioner.
In the evaporator 1 described above, as shown in FIG. 10, a two-phase refrigerant of vapor-liquid phase having passed through a compressor, a condenser, and an expansion valve (pressure-reducing device) enters the refrigerant inlet header section 5 from the refrigerant inlet pipe 7 through the refrigerant inflow port 45 of the pipe joint member 21 and the refrigerant inlet 37 of the right closing member 19. Then, the refrigerant dividedly flows into the refrigerant channels 12 a of all the heat exchange tubes 12 of the front heat exchange tube group 13.
The refrigerant having entered the refrigerant channels 12 a of all the heat exchange tubes 12 flows downward through the refrigerant channels 12 a and enters the refrigerant inflow header section 9 of the refrigerant turn tank 3. The refrigerant having entered the refrigerant inflow header section 9 passes through the refrigerant passage holes 85 of the intermediate wall 78 and enters the refrigerant outflow header section 11.
The refrigerant having entered the refrigerant outflow header section 11 dividedly flows into the refrigerant cannels 12 a of all the heat exchange tubes 12 of the rear heat exchange tube group 13; flows upward, in opposition to the previous flow direction, through the refrigerant channels 12 a; and enters the lower space 6 b of the refrigerant outlet header section 6. Since the flow-dividing resistance plate 29 imparts resistance to the flow of the refrigerant, the divided flow from the refrigerant outflow header section 11 to all the heat exchange tubes 12 of the rear heat exchange tube group 13 becomes uniform, and the divided flow from the refrigerant inlet header section 5 to all the heat exchange tubes 12 of the front heat exchange tube group 13 becomes uniform to a greater extent. As a result, the refrigerant flow rate becomes uniform among all the heat exchange tubes 12 of the two heat exchange tube groups 13.
Then, the refrigerant passes through the refrigerant passage holes 31A and 31B of the flow-dividing resistance plate 29 and enters the upper space 6 a of the refrigerant outlet header section 6. Subsequently, the refrigerant flows out to the refrigerant outlet pipe 8 through the refrigerant outlet 38 of the right closing member 19 and the refrigerant outflow port 46 of the pipe joint member 21. While flowing through the refrigerant channels 12 a of the heat exchange tubes 12 of the front heat exchange tube group 13 and through the refrigerant channels 12 a of the heat exchange tubes 12 of the rear heat exchange tube group 13, the refrigerant is subjected to heat exchange with the air flowing through the air-passing clearances in the direction of arrow X shown in FIGS. 1 and 10 flows out from the evaporator 1 in a vapor phase.
During the heat exchange, condensed water is generated on the surface of the corrugate fins 14. The condensed water flows downward onto the top face 3 a of the refrigerant turn tank 3. Then, the condensed water, by the capillary effect, enters the grooves 74; flows through the grooves 74; and drops downward below the refrigerant turn tank 3 from front and rear end portions of the grooves 74. This mechanism prevents freezing of condensed water which could otherwise result from stagnation of condensed water in a large amount in the region between the top face 3 a of the refrigerant turn tank 3 and the lower ends of the corrugate fins 14. As a result, a drop in performance of the evaporator 1 is prevented.
Embodiment 2:
The present embodiment is shown in FIGS. 11 and 12.
In FIG. 11, mutually independent plate- like caps 90 a and 90 b respectively close the right end opening of the header section body 10 of the refrigerant inlet header section 5 of the refrigerant inlet/outlet tank 2 and the right end opening of the header section body 20 of the refrigerant outlet header section 6 of the refrigerant inlet/outlet tank 2. The caps 90 a and 90 b are each formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof and are fitted into the right end openings of the header section bodies 10 and 20, respectively. The refrigerant inlet 37 for establishing communication between the interior and the exterior of the refrigerant inlet header section 5 is formed in the front cap 90 a. The refrigerant outlet 38 for establishing communication between the upper space 6 a and the exterior of the refrigerant outlet header section 6 is formed in the rear cap 90 b. The projections 42 are formed on the caps 90 a and 90 b and are fitted into the corresponding mating holes 32 and 33 formed in tubular walls of the header section bodies 10 and 20; i.e., in right end portions of the first and second members 16 and 17. That is, the caps 90 a and 90 b are configured similarly to the front cap 19 a and the rear cap 19 b, which result from eliminating the connection portion 19 c from the right closing member 19 of Embodiment 1. Since a connection portion is absent between the caps 90 a and 90 b, a cutout portion is not formed at a right end portion of the intermediate wall 27 of the second member 17 of the refrigerant inlet/outlet tank 2.
Although unillustrated, mutually independent two plate-like caps respectively close the left end opening of the header section body 10 of the refrigerant inlet header section 5 of the refrigerant inlet/outlet tank 2 and the left end opening of the header section body 20 of the refrigerant outlet header section 6 of the refrigerant inlet/outlet tank 2. The two caps are each formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof and are fitted into the left end openings of the header section bodies 10 and 20, respectively. Projections are formed on the two caps and are fitted into the corresponding mating holes 32 and 33 formed in tubular walls of the header section bodies 10 and 20; i.e., in left end portions of the first and second members 16 and 17. That is, the two caps are configured similarly to the front cap 18 a and the rear cap 18 b, which result from eliminating the connection portion 18 c from the left closing member 18 of Embodiment 1. Since a connection portion is absent between the two caps, a cutout portion is not formed at a left end portion of the intermediate wall 27 of the second member 17 of the refrigerant inlet/outlet tank 2.
These caps 90 a and 90 b and unillustrated caps are brazed to the first and second members 16 and 17 by utilization of the brazing material layers thereof in the following condition: the front cap 90 a and the unillustrated front cap are fitted into the corresponding opposite end openings of the header section body 10; the rear cap 90 b and the unillustrated rear cap are fitted into the corresponding opposite end openings of the header section body 20; and the projections 42 of the caps 90 a and 90 b and the unillustrated caps are fitted into the corresponding mating holes 32 and 33.
In FIG. 12, mutually independent plate- like caps 91 a and 91 b respectively close the right end opening of the header section body 55 of the refrigerant inflow header section 9 of the refrigerant turn tank 3 and the right end opening of the header section body 56 of the refrigerant outflow header section 11 of the refrigerant turn tank 3. The caps 91 a and 91 b are each formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof and are fitted into the right end openings of the header section bodies 55 and 56, respectively. The projections 63 are formed on the caps 91 a and 91 b and are fitted into the corresponding mating holes 60 and 61 formed in tubular walls of the header section bodies 55 and 56; i.e., in right end portions of the first and second members 70 and 71. That is, the caps 91 a and 91 b are configured similarly to the front cap 72 a and the rear cap 72 b, which result from eliminating the connection portion 72 c from the right closing member 72 of Embodiment 1. Since a connection portion is absent between the caps 91 a and 91 b, a cutout portion is not formed at a right end portion of the intermediate wall 78 of the second member 17 of the refrigerant turn tank 3.
Although unillustrated, the mutually independent plate- like caps 91 a and 91 b respectively close the left end opening of the header section body 55 of the refrigerant inflow header section 9 of the refrigerant turn tank 3 and the left end opening of the header section body 56 of the refrigerant outflow header section 11 of the refrigerant turn tank 3. The caps 91 a and 91 b are each formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof and are fitted into the left end openings of the header section bodies 55 and 56, respectively. The projections 63 are formed on the caps 91 a and 91 b and are fitted into the corresponding mating holes 60 and 61 formed in tubular walls of the header section bodies 55 and 56; i.e., in left end portions of the first and second members 70 and 71. That is, the caps 91 a and 91 b are configured similarly to the front cap 72 a and the rear cap 72 b, which result from eliminating the connection portion 72 c from the left closing member 72 of Embodiment 1. Since a connection portion is absent between the caps 91 a and 91 b, a cutout portion is not formed at a left end portion of the intermediate wall 78 of the second member 71 of the refrigerant turn tank 3.
These caps 91 a and 91 b are brazed to the first and second members 70 and 71 by utilization of the brazing material layers thereof in the following condition: the front caps 91 a are fitted into the corresponding opposite end openings of the header section body 55; the rear caps 91 b are fitted into the corresponding opposite end openings of the header section body 56; and the projections 63 of the caps 91 a and 91 b are fitted into the corresponding mating holes 60 and 61.
Other configurational features are similar to those of the evaporator 1 of Embodiment 1.
In the above-described two embodiments, the mating holes 32, 33, 60, and 61, which are formed in the tubular walls of the header section bodies 10, 20, 55, and 56; i.e., in the first and second members 16, 17, 70, and 71 and into which the projections 41, 42, and 63 are fitted, are through holes. However, the present invention is not limited thereto. The mating holes 32, 33, 60, and 61 may be closed-bottomed holes.
In the above-described two embodiments, a single heat exchange tube group 13 is provided between the refrigerant inlet header section 5 and the refrigerant inflow header section 9 of the tanks 2 and 3, respectively, and a single heat exchange tube group 13 is provided between the refrigerant outlet header section 6 and the refrigerant outflow header section 11 of the tanks 2 and 3, respectively. However, the present invention is not limited thereto. For example, the following configuration may be employed: one or more heat exchange groups 13 are provided between the refrigerant inlet header section 5 and the refrigerant inflow header section 9 of the tanks 2 and 3, respectively; and one or more heat exchange groups 13 are provided between the refrigerant outlet header section 6 and the refrigerant outflow header section 11 of the tanks 2 and 3, respectively. Also, the refrigerant turn tank may be located above the refrigerant inlet/outlet tank.
The above two embodiments are described while mentioning the heat exchanger applied to an evaporator of a car air conditioner which uses a chlorofluorocarbon-based refrigerant. However, the present invention is not limited thereto. The heat exchanger of the present invention may be used as an evaporator of a car air conditioner used in a vehicle, for example, an automobile, the car air conditioner including a compressor, a gas cooler (refrigerant cooler), an intermediate heat exchanger, an expansion valve (pressure-reducing device), and an evaporator and using a CO₂refrigerant.
In the above-described two embodiments, in order to enhance drainage performance, the refrigerant turn tank 3 has the grooves 74 formed in regions between the adjacent heat exchange tubes 12. However, the present invention is not limited thereto. Grooves for enhancing drainage performance may be formed at positions corresponding to the heat exchange tubes 12. In this case, in a region of the refrigerant turn tank 3 extending from the top face 3 a to the front and rear side surfaces 3 b, grooves for enhancing drainage performance are formed to extend from the outer ends of the tube insertion holes 75 with respect to the front-rear direction.

Claims

1. A heat exchanger comprising two header sections spaced apart from each other and a plurality of heat exchange tubes extending between the two header sections and arranged at predetermined intervals in a longitudinal direction of the two header sections with opposite end portions thereof connected to the two header sections, the two header sections each comprising a hollow header section body having opened opposite ends, and two caps closing opposite end openings of the header section body,

wherein the caps are fitted into the corresponding opposite end openings of the header section bodies; a projection is formed at a peripheral portion of each of the caps; a mating hole into which the projection of the cap is fitted is formed in a tubular wall of each of the header section bodies; and while the projections of the caps are fitted into the corresponding mating holes of the header section bodies, the caps are joined to the header section bodies.

2. A heat exchanger according to claim 1, wherein the header section bodies each comprise a first member which forms a portion of the header section body on a side toward the heat exchange tubes and to which the heat exchange tubes are connected, and a second member which forms the remaining portion of the header section body and is joined to the first member, and

the mating holes into which the corresponding projections of the caps are fitted are formed in the first and second members.

3. A heat exchanger comprising:

a heat exchange core section comprising:

a plurality of rows of heat exchange tube groups arranged in an air flow direction, each heat exchange tube group consisting of a plurality of heat exchange tubes arranged in a left-right direction at predetermined intervals; and

a plurality of fins disposed between and joined to the adjacent heat exchange tubes;

a first header section which is disposed on a first-end side of the heat exchange tubes and to which the heat exchange tubes of at least a single heat exchange tube group are connected;

a second header section which is disposed on the first-end side of the heat exchange tubes and upstream of the first header section with respect to the air flow direction and to which the heat exchange tubes of the remaining heat exchange tube group(s) are connected;

a third header section which is disposed on a second-end side of the heat exchange tubes and to which the heat exchange tubes connected to the first header section are connected; and

a fourth header section which is disposed on the second-end side of the heat exchange tubes and to which the heat exchange tubes connected to the second header section are connected;

the first to fourth header sections each comprising a hollow header section body having opened opposite ends, and two caps closing opposite end openings of the header section body,

the header section body of the first header section and the header section body of the second header section being integral with each other, and the header section body of the third header section and the header section body of the fourth header section being integral with each other,

4. A heat exchanger according to claim 3, wherein the header section body of the first header section and the header section body of the second header section are formed by a first member which forms portions of the header section bodies on a side toward the heat exchange tubes and to which the heat exchange tubes are connected, and a second member which forms the remaining portions of the header section bodies and is joined to the first member, and

5. A heat exchanger according to claim 4, wherein the two caps which close one end opening of the header section body of the first header section and one end opening of the header section body of the second header section, respectively, are integral with each other, and the two caps which close the other end opening of the header section body of the first header section and the other end opening of the header section body of the second header section, respectively, are integral with each other.

6. A heat exchanger according to claim 3, wherein the header section body of the third header section and the header section body of the fourth header section are formed by a first member which forms portions of the header section bodies on a side toward the heat exchange tubes and to which the heat exchange tubes are connected, and a second member which forms the remaining portions of the header section bodies and is joined to the first member, and

7. A heat exchanger according to claim 6, wherein the two caps which close one end opening of the header section body of the third header section and one end opening of the header section body of the fourth header section, respectively, are integral with each other, and the two caps which close the other end opening of the header section body of the third header section and the other end opening of the header section body of the fourth header section, respectively, are integral with each other.

8. A heat exchanger according to claim 3, wherein a refrigerant inlet is formed on the cap which closes one end opening of the header section body of the first header section; a refrigerant outlet is formed on the cap which closes one end opening of the header section body of the second header section located on the same side as the refrigerant inlet; and the third header section and the fourth header section communicate with each other.