WO2006028296A1

WO2006028296A1 - Laminated heat exchanger

Info

Publication number: WO2006028296A1
Application number: PCT/JP2005/017090
Authority: WO
Inventors: Daisuke Mori; Naohisa Higashiyama
Original assignee: Showa Denko K.K.
Priority date: 2004-09-10
Filing date: 2005-09-09
Publication date: 2006-03-16
Also published as: DE112005002189T5; CN101061365A; JP2006105581A; US20070295026A1

Abstract

An evaporator 1 implemented by a laminated heat exchanger has a refrigerant inlet header section 3, a refrigerant outlet header section 4, and a plurality of intermediate header sections 5 to 11. Among the header sections 3 to 11, the sixth intermediate header section 11 has a refrigerant channel which allows flow of refrigerant in the longitudinal direction thereof and whose downstream end with respect to the refrigerant flow direction is closed, and causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions. The refrigerant that has flown into the refrigerant inlet header section 3 from a refrigerant inlet 12 flows into the refrigerant outlet header section 4 through the refrigerant flow tube portions and through the intermediate header sections 5 to 11 and flows out from a refrigerant outlet 13. A resistive plate portion 38 is provided within the sixth intermediate header section 11 so as to block the refrigerant channel thereof extending in the longitudinal direction thereof. A resistive hole 36 is formed in the resistive plate portion 38 so as to impart resistance to refrigerant that flows through the refrigerant channel. When this laminated heat exchanger is applied to an evaporator of a vehicle air conditioner, temperature distribution of discharged air can be made uniform even when air-velocity distribution becomes nonuniform on the upstream side with respect to the air flow direction.

Description

DESCRIPTION

LAMINATED HEAT EXCHANGER

CROSS REFERENCE TO RELATED APPLICATIONS

This application is an application filed under 35 U.S.C. § lll(a) claiming the benefit pursuant to 35 U.S.C. § 119(e)(l) of the filing date of Provisional Application No. 60/609,831 filed September 15, 2004 pursuant to 35 U.S.C. § lll(b) .

TECHNICAL FIELD

The present invention relates to a laminated heat exchanger, and more particularly to a laminated heat exchanger used as an evaporator of a vehicle air conditioner, which is a refrigeration cycle on board a vehicle.

Herein and in the appended claims, the upper, lower, left-hand, and right-hand sides of FIGS. 1, 3, and 11 will be referred to as "upper," "lower," "left," and "right," respectively. The downstream side of flow (represented by arrow X in FIGS. 1 and 11) of air is referred to as the "front," and the opposite side as the "rear."

BACKGROUND ART

A laminated heat exchanger that is conventionally used widely as an evaporator of a vehicle air conditioner includes a plurality of flat, hollow members (refer to, for example. Japanese Patent Application Laid-Open (kokai) No. 2003-14392). Each of the flat, hollow members includes two vertically elongated metal plates whose perimetric edge portions are joined together. Two vertically extending bulging refrigerant flow tube portions are formed between the two metal plates while being spaced apart from each other in the air flow direction. A bulging header formation portion is connected to each of the upper and lower ends of each of the two refrigerant flow tube portions. The header formation portions of adjacent flat, hollow members arranged in a laminated condition are joined together. Clearances between the refrigerant flow tube portions of adjacent flat, hollow members serve as air-passing clearances. The header formation portions of the flat, hollow members form a refrigerant inlet header section having a refrigerant inlet, a refrigerant outlet header section having a refrigerant outlet, and a plurality of intermediate header sections.

The laminated heat exchanger described in the publication includes a refrigerant inlet header section; a refrigerant outlet header section arranged upstream of the refrigerant inlet header section with respect to the air flow direction; a first intermediate header section arranged under the refrigerant inlet header section; a second intermediate header section arranged in tandem alignment with the first intermediate header section; a third intermediate header section arranged above the second intermediate header section and in tandem alignment with the refrigerant inlet header section; a fourth intermediate header section arranged upstream of the third intermediate header section with respect to the air flow direction and in tandem alignment with the refrigerant outlet header section; a fifth intermediate header section arranged under the fourth intermediate header section; and a sixth intermediate header section arranged under the refrigerant outlet header section and in tandem alignment with the fifth intermediate header section. The refrigerant flow tube portions of the flat, hollow members establish communication between the refrigerant inlet header section and the first intermediate header section, communication between the second intermediate header section and the third intermediate header section, communication between the fourth intermediate header section and the fifth intermediate header section, and communication between the sixth intermediate header section and the refrigerant outlet header section. The third intermediate header section and the fourth intermediate header section communicate with each other via communication channels formed in the flat, hollow members. Each of the refrigerant inlet header section, the second intermediate header section, and the sixth intermediate header section serves as a refrigerant-flow-dividing header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction closed and which causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions. Each of the refrigerant outlet header section, the first intermediate header section, and the fifth intermediate header section serves as a refrigerant-flow-joining header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction open and which causes refrigerant flowing out from a plurality of refrigerant flow tube portions to join together. The refrigerant channel of the refrigerant inlet header section communicates with a refrigerant inlet; the refrigerant channel of the refrigerant outlet header section communicates with a refrigerant outlet; the refrigerant channel of the first intermediate header section communicates with that of the second intermediate header section; and the refrigerant channel of the fifth intermediate header section communicates with that of the sixth intermediate header section.

A laminated heat exchanger of this kind is designed for uniformly divided flow of refrigerant in terms of refrigerant flow into the refrigerant flow tube portions that establish communication between the refrigerant inlet header section and the first intermediate header section, refrigerant flow into the refrigerant flow tube portions that establish communication between the second intermediate header section and the third intermediate header section, refrigerant flow into the refrigerant flow tube portions that establish communication between the fourth intermediate header section and the fifth intermediate header section, and refrigerant flow into the refrigerant flow tube portions that establish communication between the sixth intermediate header section and the refrigerant outlet header section. In the laminated heat exchanger described in the above-mentioned publication, in order to disperse refrigerant, which flows into the refrigerant channel of the second intermediate header section from that of the first intermediate header section, over the entire second intermediate header, and to disperse refrigerant, which flows into the refrigerant channel of the sixth intermediate header section from that of the fifth intermediate header section, over the entire sixth intermediate header, a flat plate having a refrigerant passage hole is disposed between the first intermediate header section and the second intermediate header section and between the fifth intermediate header section and the sixth intermediate header section; and a guide is provided on the downstream surface of each of the flat plates with respect to the refrigerant flow direction for dispersing refrigerant that has passed through the relevant refrigerant passage holes, in the second intermediate header section and in the sixth intermediate header section.

However, in an evaporator of a vehicle air conditioner, air-velocity distribution may become nonuniform along the left-right direction on the upstream side with respect to the air flow direction; i.e., on the rear side, depending on the method of installation of the evaporator and the shape of casing of the evaporator. In this case, a vehicle-air- conditioner evaporator implemented by a laminated heat exchanger featuring uniformly divided flow of refrigerant into all refrigerant flow tube portions may involve a problem in that the temperature distribution of discharged air; i.e., the temperature distribution of air that has passed the evaporator, may become nonuniform along the left-right direction. In other words, the temperature of discharged air becomes relatively high in a region where air velocity becomes high on the rear side, and the temperature of discharged air becomes relatively low in a region where air velocity becomes low on the rear side. Further, in the region where air velocity becomes low on the rear side, condensed water may be frozen on the surfaces of refrigerant flow tube portions and fins.

An object of the present invention is to solve the above-mentioned problems and to provide a laminated heat exchanger which, when applied to, for example, an evaporator of a vehicle air conditioner, can provide uniform temperature distribution of discharged air even when air-velocity distribution becomes nonuniform on the upstream side with respect to the air flow direction.

DISCLOSURE OF THE INVENTION

To fulfill the above object, the present invention comprises the following modes.

1) A laminated heat exchanger comprising a plurality of flat, hollow members, each of the flat, hollow members comprising two vertically elongated metal plates having perimetric edge portions joined together, a bulging refrigerant flow tube portion being formed between the two metal plates, a bulging header formation portion being connected to each of opposite ends of the refrigerant flow tube portion, the header formation portions of adjacent flat, hollow members arranged in a laminated condition being joined together, clearances between the refrigerant flow tube portions of adjacent flat, hollow members serving as air- passing clearances, the header formation portions of the flat, hollow members forming a refrigerant inlet header section having a refrigerant inlet, a refrigerant outlet header section having a refrigerant outlet, and a plurality of intermediate header sections, at least one of all the header sections serving as a refrigerant-flow-dividing header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction closed and which causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions, refrigerant flowing into the refrigerant inlet header section from the refrigerant inlet, flowing through the refrigerant flow tube portions and through the intermediate header sections, flowing into the refrigerant outlet header section, and flowing out from the refrigerant outlet, wherein a resistive portion is provided in at least one of the refrigerant-flow-dividing header sections so as to impart resistance to refrigerant that flows through the refrigerant channel extending in a longitudinal direction of the refrigerant-flow-dividing header section.

2) A laminated heat exchanger according to par. 1), wherein the resistive portion comprises a resistive hole formed in a resistive plate portion that is provided within the refrigerant-flow-dividing header section in a manner to block the refrigerant channel thereof.

3) A laminated heat exchanger according to par. 2), wherein the resistive plate portion is a portion of a flat plate of metal sandwiched between and joined to two metal plates used to form the flat, hollow member, the portion of the flat plate being present within the refrigerant-flow- dividing header section; and a portion of the flat plate that is present in another header section having the refrigerant channel has a refrigerant passage hole formed therein and having a cross-sectional area equal to that of the refrigerant channel.

4) A laminated heat exchanger according to par. 2) , wherein a plurality of resistive plate portions are provided within at least one refrigerant-flow-dividing header section, and the resistive hole is formed in each of the resistive plate portions.

5) A laminated heat exchanger according to par. 4), wherein the resistive holes of different sizes are mixedly present. 6) A laminated heat exchanger according to par. 4), wherein the resistive holes of different vertical positions within the corresponding refrigerant channels are mixedly present.

7) A laminated heat exchanger according to par. 2), wherein at least one resistive plate portion is provided within each of a plurality of refrigerant-flow-dividing header sections, and the resistive hole is formed in the resistive plate portion.

8) A laminated heat exchanger according to par. 7), wherein the resistive holes of different sizes are mixedly present.

9) A laminated heat exchanger according to par. 7), wherein the resistive holes of different vertical positions within the corresponding refrigerant channels are mixedly present.

10) A laminated heat exchanger according to par. 2), wherein the size of the resistive hole is 1/60 to 1/10 the cross-sectional area of the refrigerant channel of the refrigerant-flow-dividing header section.

11) A laminated heat exchanger according to par. 2), wherein a guide portion is provided on a downstream-side surface of the resistive plate portion with respect to the refrigerant flow direction so as to guide refrigerant having passed through the resistive hole, toward the refrigerant flow tube portion near the resistive plate portion.

12) A laminated heat exchanger according to par. 1), wherein the flat, hollow member comprises the two vertically extending refrigerant flow tube portions spaced apart from each other in an air flow direction and the two header formation portions provided at each of the upper and lower end portions of the flat, hollow member, the two header formation portions being connected to corresponding upper ends of the two refrigerant flow tube portions and spaced apart from each other in the air flow direction, and the other two header formation portions being connected to corresponding lower ends of the two refrigerant flow tube portions and spaced apart from each other in the air flow direction.

13) A laminated heat exchanger according to par. 12) comprising a refrigerant inlet header section, a refrigerant outlet header section arranged upstream of the refrigerant inlet header section with respect to the air flow direction, a first intermediate header section arranged under the refrigerant inlet header section, a second intermediate header section arranged in tandem alignment with the first intermediate header section, a third intermediate header section arranged above the second intermediate header section and in tandem alignment with the refrigerant inlet header section, a fourth intermediate header section arranged upstream of the third intermediate header section with respect to the air flow direction and in tandem alignment with the refrigerant outlet header section, a fifth intermediate header section arranged under the fourth intermediate header section, and a sixth intermediate header section arranged under the refrigerant outlet header section and in tandem alignment with the fifth intermediate header section, wherein each of the refrigerant inlet header section, the first intermediate header section, the second intermediate header section, and the third intermediate header section comprises the header formation portions of the flat, hollow members located toward a downstream side with respect to the air flow direction; each of the refrigerant outlet header section, the fourth intermediate header section, the fifth intermediate header section, and the sixth intermediate header section comprises the header formation portions of the flat, hollow members located toward an upstream side with respect to the air flow direction; the refrigerant flow tube portions of the flat, hollow members establish communication between the refrigerant inlet header section and the first intermediate header section, communication between the second intermediate header section and the third intermediate header section, communication between the fourth intermediate header section and the fifth intermediate header section, and communication between the sixth intermediate header section and the refrigerant outlet header section; the third intermediate header section and the fourth intermediate header section communicate with each other via communication channels formed in the flat, hollow members; each of the refrigerant inlet header section, the second intermediate header section, and the sixth intermediate header section serves as a refrigerant-flow- dividing header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction closed and which causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions; each of the refrigerant outlet header section, the first intermediate header section, and the fifth intermediate header section serves as a refrigerant-flow- joining header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction open and which causes refrigerant flowing out from a plurality of refrigerant flow tube portions to join together; the refrigerant channel of the refrigerant inlet header section communicates with the refrigerant inlet; the refrigerant channel of the refrigerant outlet header section communicates with the refrigerant outlet; the refrigerant channel of the first intermediate header section communicates with that of the second intermediate header section; and the refrigerant channel of the fifth intermediate header section communicates with that of the sixth intermediate header section.

14) A laminated heat exchanger according to par. 1), wherein the flat, hollow member comprises a hairpin refrigerant flow tube portion, which comprises two vertically extending, bulging linear portions spaced apart from each other in the air flow direction and a bulging communication portion for establishing communication between the two bulging linear portions at upper ends thereof, and two header formation portions provided at the lower end portion of the flat, hollow member, the two header formation portions being connected to corresponding opposite ends of the refrigerant flow tube portion and spaced apart from each other in the air flow direction.

15) A laminated heat exchanger according to claim 14 comprising a refrigerant inlet header section, a refrigerant outlet header section arranged in tandem alignment with the refrigerant inlet header section, a first intermediate header section arranged downstream of the refrigerant inlet header section with respect to the air flow direction, and a second intermediate header section arranged downstream of the refrigerant outlet header section with respect to the air flow direction and in tandem alignment with the first intermediate header section, wherein each of the refrigerant inlet header section and the refrigerant outlet header section comprises the header formation portions of the flat, hollow members located toward an upstream side with respect to the air flow direction; each of the first intermediate header section and the second intermediate header section comprises the header formation portions of the flat, hollow members located toward a downstream side with respect to the air flow direction; the refrigerant flow tube portions of the flat, hollow members establish communication between the refrigerant inlet header section and the first intermediate header section and communication between the second intermediate header section and the refrigerant outlet header section; each of the refrigerant inlet header section and the second intermediate header section serves as a refrigerant- flow-dividing header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction closed and which causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions; each of the refrigerant outlet header section and the first intermediate header section serves as a refrigerant-flow-joining header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction open and which causes refrigerant flowing out from a plurality of refrigerant flow tube portions to join together; the refrigerant channel of the refrigerant inlet header section communicates with the refrigerant inlet; the refrigerant channel of the refrigerant outlet header section communicates with the refrigerant outlet; and the refrigerant channel of the first intermediate header section communicates with that of the second intermediate header section.

16) A refrigeration cycle comprising a compressor, a condenser, and an evaporator, the evaporator comprising a laminated heat exchanger according to any one of pars. 1) to 17) A vehicle having installed therein a refrigeration cycle according to par. 16) as a vehicle air conditioner.

According to the laminated heat exchanger of par. 1), the resistive portion is provided in at least one of the refrigerant-flow-dividing header sections so as to impart resistance to refrigerant that flows through the refrigerant channel extending in the longitudinal direction of the refrigerant-flow-dividing header section, so that there can be reduced the quantity of refrigerant that flows beyond the resistive portion in the refrigerant-flow-dividing header section. Accordingly, in the case where the laminated heat exchanger is used as an evaporator of a vehicle air conditioner, even when air-velocity distribution becomes nonuniform on the upstream side with respect to the air flow direction, and consequently air velocity drops in a region corresponding to the downstream side of the resistive portion with respect to the refrigerant flow direction in the refrigerant-flow-dividing header section, an extreme drop in the temperature of air that has passed through the region can be prevented. Thus, the temperature distribution of discharged air can be rendered uniform. Further, in the region where air velocity becomes low, freezing of condensed water on the surfaces of refrigerant flow tube portions and fins can be prevented.

The laminated heat exchanger of par. 2) allows the resistive portion to be formed relatively easily.

15 The laminated heat exchanger of par. 3) allows the resistive plate portion having the resistive hole to be provided relatively easily. Also, leakage of refrigerant from the flat, hollow member having the flat plate can be reliably prevented. Further, the metal plates used to form the flat, hollow member having the flat plate can be identical with those used to form other flat, hollow members, so that the manufacturing cost is lowered.

The laminated heat exchanger according to any one of pars. 4) to 9) can finely control the flow rate of refrigerant flowing through individual regions thereof in accordance with the nonuniform air-velocity distribution on the upstream side with respect to the air flow direction.

The laminated heat exchanger of par. 10) can reliably reduce the flow rate of refrigerant that flows beyond the resistive portion in the refrigerant-flow-dividing header section.

The laminated heat exchanger of par. 11) enables uniformly divided flow of refrigerant into the refrigerant flow tube portions connected to a portion of the refrigerant- flow-dividing header section that is located downstream of the resistive plate portion. When the resistive plate portion is provided within the refrigerant-flow-dividing header section, the velocity of refrigerant that has passed through the resistive hole of the resistive plate portion increases. This causes difficulty for refrigerant to flow into the refrigerant flow tube portion located in the vicinity of the resistive plate portion. However, provision of the guide portion facilitates entry of refrigerant into the refrigerant flow tube portion located in the vicinity of the resistive plate portion. As a result, uniformity can be established in terms of divided flow of refrigerant into the refrigerant flow tube portions connected to a portion of the refrigerant-flow-dividing header section that is located downstream of the resistive plate portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the overall configuration of an evaporator according to Embodiment 1 to which a heater exchanger of the present invention is applied. FIG. 2 is a sectional view taken along line A—A of FIG. 1. FIG. 3 is a sectional view taken along line 13—B of FIG. 2. FIG. 4 is a cross-sectional view of a refrigerant flow tube portion of one of most flat, hollow members used in the evaporator of FIG. 1. FIG. 5 is an exploded perspective view of a first flat, hollow member used in the evaporator of FIG. 1. FIG. 6 is an exploded perspective view of a second flat, hollow member used in the evaporator of FIG. 1. FIG. 7 is an exploded perspective view showing a third flat, hollow member and a pipe joint plate used in the evaporator of FIG. 1. FIG. 8 is an exploded perspective view of a fourth flat, hollow member used in the evaporator of FIG. 1. FIG. 9 is an exploded perspective view of a fifth flat, hollow member used in the evaporator of FIG. 1. FIG. 10 is a diagram showing the flow of refrigerant in the evaporator of FIG. 1. FIG. 11 is a perspective view showing the overall configuration of an evaporator according to Embodiment 2 to which a heat exchanger of the present invention is applied. FIG. 12 is an exploded perspective view of a first flat, hollow member used in the evaporator of FIG. 11. FIG. 13 is an exploded perspective view of a third flat, hollow member used in the evaporator of FIG. 11. FIG. 14 is an exploded perspective view of a fourth flat, hollow member used in the evaporator of FIG. 11. FIG. 15 is a diagram showing the flow of refrigerant in the evaporator of FIG. 11.

BEST MODE OF CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings. The embodiments are of a laminated heat exchanger according to the present invention that is applied to an evaporator of a vehicle air conditioner.

In the following description, the term "aluminum" includes aluminum alloys in addition to pure aluminum. Embodiment 1

The present embodiment is shown in FIGS. 1 to 10.

FIGS. 1 to 3 show the overall configuration of an evaporator of Embodiment 1; FIGS. 4 to 9 show the configurations of essential portions of the evaporator; and FIG. 10 shows the flow of refrigerant in the evaporator.

Referring to FIGS. 1 to 3, the evaporator (1) is configured such that a plurality of flat, hollow members (2A), (2B), (2C), (2D), and (2E) each having a vertically elongated rectangular shape are arranged in a laminated condition in the left-right direction and joined together while their widths extend in the front-rear direction (air flow direction). The evaporator (1) includes a refrigerant inlet header section (3) extending in the left-right direction; a refrigerant outlet header section (4) provided rearward (upstream, with respect to the air flow direction) of the refrigerant inlet header section (3) and extending in the left-right direction; a first intermediate header section (5) provided under the refrigerant inlet header section (3) and extending in the left-right direction; a second intermediate header section (6) provided continuous with and leftward of the first intermediate header section (5) and extending in the left-right direction; a third intermediate header section (7) provided above the second intermediate header section (6) and continuous with and leftward of the refrigerant inlet header section (3) and extending in the left-right direction; a fourth intermediate header section (8) provided rearward of the third intermediate header section (7) and continuous with and leftward of the refrigerant outlet header section (4) and extending in the left-right direction; a fifth intermediate header section (9) provided below the fourth intermediate header section (8) and extending in the left-right direction; and a sixth intermediate header section (11) provided continuous with and rightward of the fifth intermediate header section (9) and under the refrigerant outlet header section ( 4 ) ( see FIG . 10 ) .

A refrigerant inlet (12) is formed, at the right end of the refrigerant inlet header section (3), and. a refrigerant outlet (13) is formed at the right end of the refrigerant outlet header section (4). An aluminum joint plate (14) is joined to right end portions of the refrigerant inlet and outlet header sections (3) and (4). The joint plate (14) has a refrigerant inflow port (14a) communicating with the refrigerant inlet (12), and a refrigerant outflow port (14b) communicating with the refrigerant outlet (13). A refrigerant inlet pipe (not shown) is connected to the refrigerant inflow port (14a) of the joint plate (14), and a refrigerant outlet pipe (not shown) is connected to the refrigerant outflow port (14b).

As shown in FIGS. 2 to 4, each of the flat, hollow members (2A), (2B), (2C), (2D), and (2E) includes two vertically extending rectangular aluminum plates (15A), (15B), (15C), or (15D) whose perimetric edge portions are brazed together. Each of the aluminum plates (15A), (15B), (15C), and (15D) is formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof. Two vertically extending front-side and rear-side bulging refrigerant flow tube portions (16) and (17) and bulging header formation portions (18) and (19) are provided between the two aluminum plates (15A), (15B), (15C), or (15D), which partially constitute the flat, hollow member (2A), (2B), (2C), (2D), or (2E). The bulging header formation portions (18) and (19) are connected to corresponding upper and lower end portions of the refrigerant flow tube portions (16) and (17). An aluminum corrugate inner fin (21) is disposed in each of the flat, hollow members excluding the flat, hollow members (2D) and (2E); i.e., in each of the flat, hollow members (2A), (2B), and (2C), in such a manner as to extend across the front-side and rear-side refrigerant flow tube portions (16) and (17). The corrugate inner fin (21) is brazed to the two aluminum plates (15A), (15B), or (15C). Two aluminum corrugate inner fins may be disposed separately in the corresponding refrigerant flow tube portions (16) and (17).

In the flat, hollow members (2A), (2B), (2C), (2D), and (2E), the height of the header formation portions (18) and (19) in the left-right direction is greater than that of the refrigerant flow tube portions (16) and (17). The header formation portions (18) or (19) of the adjacent flat, hollow members (2A), (2B), (2C), (2D), or (2E) are brazed together. The front-side upper and lower header formation portions (18) of the flat, hollow members (2A), (2B), (2C), (2D), and (2E) form the refrigerant inlet header section (3) and the first to third intermediate header sections (5) to (7). Similarly, the rear-side upper and lower header formation portions (19) form the refrigerant outlet header section (4) and the fourth to sixth intermediate header sections (8) to (11). Clearances between the refrigerant flow tube portions (16) and between the refrigerant flow tube portions (17) of the adjacent flat, hollow members (2A), (2B), (2C), (2D), and (2E) serve as air-passing clearances. Aluminum corrugate outer fins (22) are disposed in the corresponding air-passing clearances and brazed to the corresponding flat, hollow members (2A), (2B), (2C), (2D), and (2E). The refrigerant flow tube portions (16) and (17) and the outer fins (22) constitute a heat exchange core section.

FIG. 5 shows the configuration of the first flat, hollow member (2A), which is one of the flat, hollow members used to form the refrigerant inlet header section (3), the refrigerant outlet header section (4), the first intermediate header section (5), and the sixth intermediate header section (11) and excluding the flat, hollow members (2C) disposed at the left and right ends, the flat, hollow member (2D) disposed at a central position with respect to the left-right direction, and the flat, hollow member (2E) disposed a predetermined distance away from the right end. As shown in FIG. 5, the right-hand aluminum plate (15A) used to partially constitute the first flat, hollow member (2A) includes two vertically extending, rightward bulging, front-side and rear- side tube-portion-forming bulging portions (23) and four rightward bulging, header-forming bulging portions (24) connected to the corresponding upper and lower ends of the tube-portion-forming bulging portions (23) and having a bulging height greater than that of the tube-portion-forming bulging portions (23). The top wall of each of the header- forming bulging portions (24) is punched out to thereby form a through-hole (25). The left-hand aluminum plate (15A) used to partially constitute the first flat, hollow member (2A) is a mirror image of the right-hand aluminum plate (15A), and like portions are denoted by like reference numerals . The two aluminum plates (15A) are assembled such that the openings of the tube-portion-forming and header-forming bulging portions (23) and (24) are opposed to each other while the inner fin (21) is sandwiched therebetween, followed by brazing. Thus is formed the first flat, hollow member (2A). The header formation portions (18) and (19) of the two adjacent first flat, hollow members (2A) are respectively joined together in a communicating condition such that slightly size-reduced end portions of the header-forming bulging portions (24) of one first flat, hollow member (2A) are press-fitted into and brazed to the corresponding through-holes (25) of the header-forming bulging portions (24) of the other first flat, hollow member (2A).

FIG. 6 shows the configuration of the second flat, hollow member (2B), which is one of the flat, hollow members used to form the second intermediate header section (6), the third intermediate header section (7), the fourth intermediate header section (8), and the fifth intermediate header section (9) and excluding the flat, hollow member (2C) disposed at the left end and the flat, hollow member (2D) disposed at a central position with respect to the left-right direction. As shown in FIG. 6, an outward bulging communication-channel-forming bulging portion (26) is formed on the right-hand aluminum plate (15B) of the second flat, hollow member (2B) between the two upper header-forming bulging portions (24) such that the height thereof is slightly smaller than that of the header-forming bulging portions (24). Thus, the two header-forming bulging portions (24) communicate with each other via the communication- channel-forming bulging portion (26). The left-hand aluminum plate (15B) of the second flat, hollow member (2B) is a mirror image of the right-hand aluminum plate (15B), and like portions are denoted by like reference numerals. The communication-channel-forming bulging portions (26) of the two aluminum plates (15B) form a bulging communication channel (27). Other configurational features of the second flat, hollow member (2B) are identical with those of the first flat, hollow member (2A) shown in FIG. 5. The header formation portions (18) and (19) of the two adjacent second flat, hollow members (2B) are respectively joined together in a communicating condition as in the case of joining of the adjacent first flat, hollow members (2A).

FIG. 7 shows the configuration of the third flat, hollow member (2C) disposed at the right end. As shown in FIG. 7, in the right-hand aluminum plate (15C) used to partially constitute the third flat, hollow member (2C), the bulging height of all header-forming bulging portions (24A) is equal to that of the tube-portion-forming bulging portions (23). Also, in the right-hand aluminum plate (15C), no through-hole is formed in each of the top walls of the two lower header-forming bulging portions (24A). Further, in the right-hand aluminum plate (15C), a through-hole serving as the refrigerant inlet (12) is formed in the top wall of the upper front-side header-forming bulging portion (24A), and a through-hole serving as the refrigerant outlet (13) is formed in the top wall of the upper rear-side header-forming bulging portion (24A). Rightward projecting flange portions (28) and (29) are integrally formed on the corresponding top walls of the header-forming bulging portions (24A) around the refrigerant inlet and outlet (12) and (13), respectively. Other configurational features of the third flat, hollow member (2C) are identical with those of the first flat, hollow member (2A) shown in FIG. 5. Header formation portions (18A) and (19A) of the third flat, hollow member (2C) are joined, in a communicating condition, to the header formation portions (18) and (19), respectively, of the left- hand adjacent first flat, hollow member (2A) as in the case of joining of the adjacent first flat, hollow members (2A). While the two flange portions (28) and (29) of the third flat, hollow member (2C) are inserted into the refrigerant inflow port (14a) and the refrigerant outflow port (14b), respectively, of the pipe joint plate (14), the pipe joint plate (14) is brazed to the third flat, hollow member (2C). Although detailed illustrations are omitted, the flat, hollow member (2C) disposed at the left end is identical in configuration with the third flat, hollow member (2C), except that no through-hole is formed in the top walls of all the header-forming bulging portions (24A) and that the pipe joint plate (14) is not brazed thereto. The left-end flat, hollow member (2C) is arranged in a mirror-image manner in relation to the third flat, hollow member (2C).

FIG. 8 shows the configuration of the fourth flat, hollow member (2D) disposed at a central position with respect to the left-right direction. As shown in FIG. 8, in the two aluminum plates (15D) used to partially constitute the fourth flat, hollow member (2D), a plurality of vertically extending, inward projecting ribs (31) are formed at front-rear intervals on the top walls of the tube-portion- forming bulging portions (23) by inwardly deforming the top walls. The projecting height of the ribs (31) is equal to that of the tube-portion-forming bulging portions (23). A vertically elongated rectangular flat plate (32) made of aluminum is sandwiched between the two aluminum plates (15D). Perimetric edge portions of the flat plate (32) are brazed to the two aluminum plates (15D) while been sandwiched between perimetric edge portions of the two aluminum plates (15D). Projecting end portions of the ribs (31) of the two aluminum plates (15A) are brazed to the flat plate (32). Two through- holes (33) are formed at a lower end portion of the flat plate (32) at positions corresponding to the two through- holes (25) of each of the two aluminum plates (15A) and have a diameter equal to that of the through-holes (25). An inner fin is not disposed within the fourth flat, hollow member (2D). Other configurational features of the fourth flat, hollow member (2D) are identical with those of the first flat. hollow member (2A) shown in FIG. 5. The header formation portions (18) and (19) of the fourth flat, hollow member (2D) are joined, in a communicating condition, to the header formation portions (18) and (19), respectively, of the right- hand adjacent first flat, hollow member (2A) and to the header formation portions (18) and (19), respectively, of the left-hand adjacent second flat, hollow member (2B) as in the case of joining of the adjacent first flat, hollow members (2A). The flat plate (32) separates the refrigerant inlet header section (3) and the third intermediate header section (7) from each other and the refrigerant outlet header section (4) and the fourth intermediate header section (8) from each other. The two through-holes (33) establish communication between the first intermediate header section (5) and the second intermediate header section (6) and communication between the fifth intermediate header section (9) and the sixth intermediate header section (11).

FIG. 9 shows the configuration of the fifth flat, hollow member (2E) disposed a predetermined distance away from the right end. As shown in FIG. 9, two aluminum plates (15D) similar to those used to partially constitute the fourth flat, hollow member (2D) shown in FIG. 8 are used to partially constitute the fifth flat, hollow member (2E). A vertically elongated rectangular flat plate (34) made of aluminum is sandwiched between the two aluminum plates (15D). Perimetric edge portions of the flat plate (34) are brazed to the two aluminum plates (15D) while been sandwiched between perimetric edge portions of the two aluminum plates (15D). Two through-holes (35) are formed at an upper end portion of the flat plate (34) at positions corresponding to the two through-holes (25) formed in an upper end portion of each of the two aluminum plates (15D), and one through-hole (35) is formed at a lower end portion of the flat plate (34) at a position corresponding to the front-side through-holes (25) of the two aluminum plates (15D). The through-holes (35) have a diameter equal to that of the through-holes (25). A resistive hole (36) that, in the present embodiment, assumes a circular shape is formed at the lower end portion of the flat plate (34) at a position corresponding to the rear-side through-holes (25) of the two aluminum plates (15D) and has a diameter smaller than that of the through-holes (25). A guide portion (37) that, in the present embodiment, assumes a partially spherical shape is integrally formed on the right- hand surface of the flat plate (34) at a position below the resistive hole (36) and is adapted to guide refrigerant that has passed through the resistive hole (36), toward an upward direction; i.e., toward the rear-side refrigerant flow tube portion (17) in the vicinity of the flat plate (34). Other configurational features of the fifth flat, hollow member (2E) are identical with those of the fourth flat, hollow member (2D) shown in FIG. 8. The header formation portions (18) and (19) of the fifth flat, hollow member (2E) are joined, in a communicating condition, to the header formation portions (18) and (19), respectively, of the left-hand and right-hand adjacent first flat, hollow members (2A) as in the case of joining of the adjacent first flat, hollow members (2A).

The front-side refrigerant flow tube portions (16) of the flat, hollow members (2A), (2B), (2C), (2D), and (2E) establish communication between the refrigerant inlet header section (3) and the first intermediate header section (5) and communication between the second intermediate header section (6) and the third intermediate header section (7). The rear- side refrigerant flow tube portions (17) of the flat, hollow members (2A), (2B), (2C), (2D), and (2E) establish communication between the refrigerant outlet header section (4) and the sixth intermediate header section (11) and communication between the fourth intermediate header section (8) and the fifth intermediate header section (9). The third intermediate header section (7) and the fourth intermediate header section (8) communicate with each other via the communication channels (27) formed in the second flat, hollow members (2B). Each of the refrigerant inlet header section (3), the second intermediate header section (6), and the sixth intermediate header section (11) serves as a refrigerant-flow-dividing header section. The refrigerant- flow-dividing header section has a refrigerant channel which allows flow of refrigerant in the longitudinal direction thereof and whose downstream end with respect to the refrigerant flow direction is closed, and causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions (16) and (17). Each of the refrigerant outlet header section (4), the first intermediate header section (5), and the fifth intermediate header section (9) serves as a refrigerant-flow-joining header section. The refrigerant- flow-joining header section has a refrigerant channel which allows flow of refrigerant in the longitudinal direction thereof and whose downstream end with respect to the refrigerant flow direction is open, and causes refrigerant flowing out from a plurality of refrigerant flow tube portions (16) and (17) to join together. The refrigerant channel of the refrigerant inlet header section (3) communicates with the refrigerant inlet (12); the refrigerant channel of the refrigerant outlet header section (4) communicates with the refrigerant outlet (13); the refrigerant channel of the first intermediate header section (5) communicates with that of the second intermediate header section (6) ; and the refrigerant channel of the fifth intermediate header section (9) communicates with that of the sixth intermediate header section (11). A rear-side portion of a lower end portion of the flat plate (34) of the fifth flat, hollow member (2E); i.e., a portion of the flat plate (34) that is present within the sixth intermediate header section (11), is a resistive plate portion (38) that blocks the refrigerant channel of the sixth intermediate header section (11). The resistive hole (36) formed in the resistive plate portion (38) imparts resistance to refrigerant that flows through the refrigerant channel of the sixth intermediate header section (11). Preferably, the size of the resistive hole (36) is 1/60 to 1/10 the cross- sectional area (hatched in FIG. 10) of the refrigerant channel of the sixth intermediate header section (11). It is experimentally obtained that the preferred size of the resistive hole (36) is 1/60 to 1/10 the cross-sectional area of the refrigerant channel of the sixth intermediate header section (11). When the size of the resistive hole (36) is less than 1/60 the cross-sectional area of the refrigerant channel of the sixth intermediate header section (11), the quantity of refrigerant that flows beyond the resistive plate portion (38) excessively reduces. When the size of the resistive hole (36) is greater than 1/10 the cross-sectional area, the effect of correcting the nonuniform temperature distribution of discharged air, which is caused by nonuniform air-velocity distribution on the upstream side with respect to the air flow direction, may become insufficient.

In manufacture of the evaporator (1) , component members thereof are assembled and tentatively fixed together, and the assembled component members are brazed together.

The evaporator (1) is accommodated in a casing disposed within a compartment of a vehicle; for example, an automobile, and, together with a compressor and a condenser, constitutes a refrigeration cycle, which is used as a vehicle air conditioner.

In the evaporator (1) described above, as shown in FIG. 10, two-phase refrigerant of vapor-liquid phase having passed through a compressor, a condenser, and an expansion valve (pressure-reducing means) enters the refrigerant inlet header section (3) from an inlet pipe through the refrigerant inflow port (14a) of the pipe joint plate (14) and the refrigerant inlet (12). As the refrigerant having entered the refrigerant inlet header section (3) flows leftward through the refrigerant channel, the refrigerant dividedly flows into the front-side refrigerant flow tube portions (16) connected to the refrigerant inlet header section (3); flows downward through the refrigerant flow tube portions (16); enters the first intermediate header section (5); joiningly flows leftward through the refrigerant channel of the first intermediate header section (5); and enters the second intermediate header section (6) through the through-hole (33). As the refrigerant having entered the second intermediate header section (6) flows leftward through the refrigerant channel, the refrigerant dividedly flows into the front-side refrigerant flow tube portions (16) connected to the second intermediate header section (6); flows upward through the refrigerant flow tube portions (16); and enters the third intermediate header section (7). The refrigerant having entered the third intermediate header section (7) enters the fourth intermediate header section (8) through the communication channels (27) of the second flat, hollow member (2B). As the refrigerant having entered the fourth intermediate header section (8) flows rightward through the refrigerant channel, the refrigerant dividedly flows into the rear-side refrigerant flow tube portions (17) connected to the fourth intermediate header section (8); flows downward through the refrigerant flow tube portions (17); and enters the fifth intermediate header section (9) and joins together. The refrigerant having entered the fifth intermediate header section (9) flows rightward through the refrigerant channel; and enters the sixth intermediate header section (11) through the through-hole (33). As the refrigerant having entered the sixth intermediate header section (11) flows rightward through the refrigerant channel, the refrigerant dividedly flows into the rear-side refrigerant flow tube portions (17) connected to the sixth intermediate header section (11); flows upward through the refrigerant flow tube portions (17); and enters the refrigerant outlet header section (4). The refrigerant having entered the refrigerant outlet header section (4) enters an outlet pipe through the refrigerant outlet (13) and the refrigerant outflow port (14b) of the pipe joint plate (14) and flows out from the outlet pipe. While flowing through the refrigerant flow tube portions (16) and (17) of the flat, hollow members (2A), (2B), (2C), (2D), and (2E), 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 and flows out from the evaporator (1) in a vapor phase.

Since the cross-sectional area of the refrigerant channel of the sixth intermediate header section (11) is reduced by the resistive hole (36) of the resistive plate portion (38), the quantity of refrigerant that flows through a portion of the refrigerant channel located downstream of the resistive plate portion (38) becomes relatively small, so that the quantity of refrigerant that flows through the refrigerant flow tube portions (17) connected to the portion of the refrigerant channel becomes relatively small. Accordingly, even when air-velocity distribution becomes nonuniform on the upstream side with respect to the air flow direction, and consequently air velocity drops in a region located rightward of the resistive plate portion (38), an extreme drop in the temperature of air having passed through the region can be prevented, so that the temperature distribution of discharged air can be rendered uniform. Further, in the region where air velocity becomes low, freezing of condensed water on the surfaces of refrigerant flow tube portions and fins can be prevented.

When the resistive plate portion (38) is provided within the sixth intermediate header section (11), the velocity of refrigerant having passed through the resistive hole (36) of the resistive plate portion (38) increases. This causes difficulty for refrigerant to flow into the refrigerant flow tube portion (17) located in the vicinity of the resistive plate portion (38). However, provision of the guide portion (37) facilitates entry of refrigerant into the refrigerant flow tube portion (17) located in the vicinity of the resistive plate portion (38). As a result, uniformity can be established in terms of divided flow of refrigerant into the refrigerant flow tube portions (17) connected to a portion of the sixth intermediate header section (11) that is located downstream of the resistive plate portion (38).

In Embodiment 1 described above, the resistive plate portion (38) is provided within the sixth intermediate header section (11), and the resistive hole (36) is formed in the resistive plate portion (38). However, the present invention is not limited thereto. A plurality of resistive plate portions may be provided within at least any one of refrigerant-flow-dividing header sections; i.e., at least one of the refrigerant inlet header section (3), the second intermediate header section (6) , and the sixth intermediate header section (11), while a resistive hole is formed in each of the resistive plate portions. Alternatively, at least one resistive plate portion may be provided within each of a plurality of refrigerant-flow-dividing header sections; i.e., each of at least two of the refrigerant inlet header section (3), the second intermediate header section (6), and the sixth intermediate header section (11), while a resistive hole is formed in each of the resistive plate portions. In these cases, the resistive holes of different sizes may mixedly be present. Also, the resistive holes of different vertical positions within the corresponding refrigerant channels may mixedly be present. Embodiment 2

The present embodiment is shown in FIGS. 11 to 15.

FIG. 11 shows the overall configuration of an evaporator of Embodiment 2; FIGS. 12 to 14 show the configurations of essential portions of the evaporator; and FIG. 15 shows the flow of refrigerant in the evaporator.

Referring to FIG. 11, the evaporator (40) is configured such that a plurality of flat, hollow members (41A), (41B), (41C), and (41D) each having a vertically elongated rectangular shape are arranged in a laminated condition in the left-right direction and joined together while their widths extend in the front-rear direction (air flow direction). The evaporator (40) includes a refrigerant inlet header section (42) extending in the left-right direction; a refrigerant outlet header section (43) provided continuous with and rightward of the refrigerant inlet header section (42) and extending in the left-right direction; a first intermediate header section (44) provided frontward (downstream, with respect to the air flow direction) of the refrigerant inlet header section (42) and extending in the left-right direction; and a second intermediate header section (45) provided continuous with and rightward of the first intermediate header section (44) and frontward of the refrigerant outlet header section (43) (see FIG. 15).

A refrigerant inlet (46) is formed at the left end of the refrigerant inlet header section (42), and a refrigerant outlet (47) is formed at the right end of the refrigerant outlet header section (43). Although unillustrated, by use of appropriate means, a refrigerant inlet pipe (not shown) is connected to the refrigerant inlet (46), and a refrigerant outlet pipe (not shown) is connected to the refrigerant outlet (47).

As shown in FIGS. 11 to 14, each of the flat, hollow members (41A), (41B), (41C), and (41D) includes two vertically extending rectangular aluminum plates (48A), (48B), or (48C) whose perimetric edge portions are brazed together. Each of the aluminum plates (48A), (48B), and (48C) is formed from an aluminum brazing sheet having a brazing material layer on each of opposite sides thereof. A hairpin refrigerant flow tube portion (50) and two bulging header formation portions (53) and (54) are provided between the two aluminum plates (48A), (48B), or (48C), which partially constitute the flat, hollow member (41A), (41B), (41C), or (41D). The hairpin refrigerant flow tube portion (50) includes two vertically extending, bulging linear portions (51) and a bulging communication portion (52) for establishing communication between the two bulging linear portions (51) at upper ends thereof. The two bulging header formation portions (53) and (54) are connected to corresponding lower end portions of the two bulging linear portions (51) of the refrigerant flow tube portion (50). An aluminum corrugate inner fin (55) is disposed in each of the flat, hollow members excluding the flat, hollow members (41C) and (41D); i.e., in each of the flat, hollow members (41A) and (41B), in such a manner as to extend across the two bulging linear portions (51) of the refrigerant flow tube portion (50). The corrugate inner fin (55) is brazed to the two aluminum plates (48A). Two aluminum corrugate inner fins may be disposed separately in the corresponding bulging linear portions (51) of the refrigerant flow tube portion (50).

In the flat, hollow members (41A), (41B), (41C), and (41D), the height of the header formation portions (53) and (54) in the left-right direction is greater than that of the refrigerant flow tube portion (50). The header formation portions (53) or (54) of the adjacent flat, hollow members (41A), (41B), (41C), or (41D) are brazed together. The rear- side header formation portions (53) of the flat, hollow members (41A), (41B), (41C), and (41D) form the refrigerant inlet header section (42) and the refrigerant outlet header section (43). Similarly, the front-side header formation portions (54) form the first and second intermediate header sections (44) and (45). Clearances between the refrigerant flow tube portions (50) of the adjacent flat, hollow members (41A), (41B), (41C), and (41D) serve as air-passing clearances. Aluminum corrugate outer fins (56) are disposed in the corresponding air-passing clearances and brazed to the corresponding flat, hollow members (41A), (41B), (41C), and (41D). The refrigerant flow tube portions (50) and the outer fins (56) constitute a heat exchange core section.

FIG. 12 shows the configuration of the first flat, hollow member (41A), which is one of the flat, hollow members excluding the flat, hollow members (41B) disposed at the left and right ends, the flat, hollow member (41C) disposed at a central position with respect to the left-right direction, and the flat, hollow member (41D) disposed a predetermined distance away from the right end. As shown in FIG. 12, the right-hand aluminum plate (48A) used to partially constitute the first flat, hollow member (41A) includes two vertically extending, rightward bulging, front-side and rear-side linear-portion-forming bulging portions (57); a rightward bulging, communication-portion-forming bulging portion (58) adapted to establish communication between upper end portions of the linear-portion-forming bulging portions (57) and having a bulging height equal to that of the linear-portion- forming bulging portions (57); and two rightward bulging, header-forming bulging portions (59) connected to the corresponding lower ends of the linear-portion-forming bulging portions (57) and having a bulging height greater than that of the linear-portion-forming and communication- portion-forming bulging portions (57) and (58). A plurality of inward projecting arcuate ribs (61) are formed at certain intervals on the top wall of the communication-portion- forming bulging portion (58) by inwardly deforming the top wall. The ribs (61) have a bulging height equal to that of the linear-portion-forming bulging portions (57). The top wall of each of the header-forming bulging portions (59) is punched out to thereby form a through-hole (60). The left- hand aluminum plate (48A) used to partially constitute the first flat, hollow member (41A) is a mirror image of the right-hand aluminum plate (48A), and like portions are denoted by like reference numerals. The two aluminum plates (48A) are assembled such that the openings of the linear- portion-forming, communication-portion-forming, and header- forming bulging portions (57), (58), and (59) are opposed to each other while the inner fin (55) is sandwiched therebetween, followed by brazing. Thus is formed the first flat, hollow member (41A). The header formation portions (53) and (54) of the two adjacent first flat, hollow members (41A) are respectively joined together in a communicating condition such that slightly size-reduced end portions of the header-forming bulging portions (59) of one first flat, hollow member (41A) are press-fitted into and brazed to the corresponding through-holes (60) of the header-forming bulging portions (59) of the other first flat, hollow member (41A).

As shown in FIG. 11, in the right-hand aluminum plate (48B) used to partially constitute the second flat, hollow member (41B) disposed at the right end, the bulging height of two header-forming bulging portions (59A) is equal to that of the linear-portion-forming bulging portions (57). Also, in the right-hand aluminum plate (48B), no through-hole is formed in each of the top walls of the two lower header- forming bulging portions (59A), whereas the refrigerant outlet (47) is formed in the top wall of the lower rear-side header-forming bulging portion (59A). Other configurational features of the second flat, hollow member (41B) are identical with those of the first flat, hollow member (41A) shown in FIG. 12. The header formation portions (53) and. (54) of the second flat, hollow member (41B) are joined, in a communicating condition, to the header formation portions (53) and (54), respectively, of the left-hand adjacent first flat, hollow member (41A) as in the case of joining of the adjacent first flat, hollow members (41A).

Although unillustrated, the flat, hollow member (41B) disposed at the left end is arranged in a mirror-image manner in relation to the second flat, hollow member (41B) disposed at the right end and is identical in configuration with the second flat, hollow member (41B), except that, in place of the refrigerant outlet (47), the refrigerant inlet (46) is formed in the rear-side header-forming bulging portion (59A) of the aluminum plate (48B).

FIG. 13 shows the configuration of the third flat, hollow member (41C) disposed at a central position with respect to the left-right direction. As shown in FIG. 13, in the two aluminum plates (48C) used to partially constitute the third flat, hollow member (41C), a plurality of vertically extending, inward projecting ribs (62) are formed at front-rear intervals on the top walls of the linear- portion-forming bulging portions (57) by inwardly deforming the top walls. The projecting height of the ribs (62) is equal to that of the linear-portion-forming bulging portions (57). A vertically elongated rectangular flat plate (63) made of aluminum is sandwiched between the two aluminum plates (48C). Perimetric edge portions of the flat plate (63) are brazed to the two aluminum plates (48C) while been sandwiched between perimetric edge portions of the two aluminum plates (48C). Projecting end portions of the ribs (62) of the two aluminum plates (48C) are brazed to the flat plate (63). A through-hole (64) is formed at a lower end portion of the flat plate (63) at a position corresponding to the front-side through-hole (60) of each of the two aluminum plates (48C) and has a diameter equal to that of the through- hole (60). An inner fin is not disposed within the third flat, hollow member (41C). Other configurational features of the third flat, hollow member (41C) are identical with those of the first flat, hollow member (41A) shown in FIG. 12. The header formation portions (53) and (54) of the third flat, hollow member (41C) are joined, in a communicating condition, to the header formation portions (53) and (54), respectively, of the left-hand and right-hand adjacent first flat, hollow members (41A) as in the case of joining of the adjacent first flat, hollow members (41A). The flat plate (63) separates the refrigerant inlet header section (42) and the refrigerant outlet header section (43) from each other. The through-hole

(64) establishes communication between the first intermediate header section (44) and the second intermediate header section (45) .

FIG. 14 shows the configuration of the fourth flat, hollow member (41D) disposed a predetermined distance away from the right end. As shown in FIG. 14, two aluminum plates (48C) similar to those used to partially constitute the third flat, hollow member (41C) shown in FIG. 13 are used to partially constitute the fourth flat, hollow member (41D). A vertically elongated rectangular flat plate (65) made of aluminum is sandwiched between the two aluminum plates (48C). Perimetric edge portions of the flat plate (65) are brazed to the two aluminum plates (48C) while been sandwiched between perimetric edge portions of the two aluminum plates (48C). A through-hole (66) is formed at a lower end portion of the flat plate (65) at a position corresponding to the rear-side through-holes (60) of the two aluminum plates (48C). The through-hole (66) has a diameter equal to that of the through-hole (60). A resistive hole (67) that, in the present embodiment, assumes a circular shape is formed at the lower end portion of the flat plate (65) at a position corresponding to the front-side through-holes (60) of the two aluminum plates (48C) and has a diameter smaller than that of the through-holes (60). A guide portion (68) that, in the present embodiment, assumes a partially spherical shape is integrally formed on the right-hand surface of the flat plate (65) at a position below the resistive hole (67) and is adapted to guide refrigerant having passed through the resistive hole (67), toward an upward direction; i.e., toward the front-side, bulging linear portion (51) of the refrigerant flow tube portion (50) in the vicinity of the flat plate (65). Other configurational features of the fourth flat, hollow member (41D) are identical with those of the third flat, hollow member (41C) shown in FIG. 13. The header formation portions (53) and (54) of the fourth flat, hollow member (41D) are joined, in a communicating condition, to the header formation portions (53) and (54), respectively, of the left-hand and right-hand adjacent first flat, hollow members (41A) as in the case of joining of the adjacent first flat, hollow members (41A).

The refrigerant flow tube portions (50) of the flat, hollow members (41A), (41B), (41C), and (41D) establish communication between the refrigerant inlet header section (42) and the first intermediate header section (44) and communication between the second intermediate header section (45) and the refrigerant outlet header section (43). Each of the refrigerant inlet header section (42) and the second intermediate header section (45) serves as a refrigerant- flow-dividing header section. The refrigerant-flow-dividing header section has a refrigerant channel which allows flow of refrigerant in the longitudinal direction thereof and whose downstream end with respect to the refrigerant flow direction is closed, and causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions (50). Each of the first intermediate header section (44) and the refrigerant outlet header section (43) serves as a refrigerant-flow-joining header section. The refrigerant- flow-joining header section has a refrigerant channel which allows flow of refrigerant in the longitudinal direction thereof and whose downstream end with respect to the refrigerant flow direction is open, and causes refrigerant flowing out from a plurality of refrigerant flow tube portions (50) to join together. The refrigerant channel of the refrigerant inlet header section (42) communicates with the refrigerant inlet (46); the refrigerant channel of the refrigerant outlet header section (43) communicates with the refrigerant outlet (47); and the refrigerant channel of the first intermediate header section (44) communicates with that of the second intermediate header section (45) via the through-hole (64). A front-side portion of a lower end portion of the flat plate (65) of the fourth flat, hollow member (41D); i.e., a portion of the flat plate (65) that is present within the second intermediate header section (45), is a resistive plate portion (69) that blocks the refrigerant channel of the second intermediate header section (45). The resistive hole (67) formed in the resistive plate portion (69) reduces the cross-sectional area of the refrigerant channel of the second intermediate header section (45). Preferably, the size of the resistive hole (67) is 1/60 to 1/10 the cross-sectional area (hatched in FIG. 15) of the refrigerant channel of the second intermediate header section (45). The reason for this is similar to that of Embodiment 1.

In manufacture of the evaporator (40), component members thereof are assembled and tentatively fixed together, and the assembled component members are brazed together.

The evaporator (40) is accommodated in a casing disposed within a compartment of a vehicle; for example, an automobile, and, together with a compressor and a condenser, constitutes a refrigeration cycle, which is used as a vehicle air conditioner.

In the evaporator (40) described above, as shown in FIG. 15, two-phase refrigerant of vapor-liquid phase having passed through a compressor, a condenser, and an expansion valve (pressure-reducing means) enters the refrigerant inlet header section (42) from an inlet pipe through the refrigerant inlet (46). As the refrigerant having entered the refrigerant inlet header section (42) flows rightward through the refrigerant channel, the refrigerant dividedly flows into the refrigerant flow tube portions (50) connected to the refrigerant inlet header section (42); flows through the refrigerant flow tube portions (50); enters the first intermediate header section (44); joiningly flows rightward through the refrigerant channel of the first intermediate header section (44); and enters the second intermediate header section (45) through the through-hole (64). As the refrigerant having entered the second intermediate header section (45) flows rightward through the refrigerant channel, the refrigerant dividedly flows into the refrigerant flow tube portions (50) connected to the second intermediate header section (45); flows through the refrigerant flow tube portions (50); and enters the refrigerant outlet header section (43). The refrigerant having entered the refrigerant outlet header section (43) enters an outlet pipe through the refrigerant outlet (47) and flows out from the outlet pipe. While flowing through the refrigerant flow tube portions (50) of the flat, hollow members (41A), (41B), (41C), and (41D), 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. 11 and 15 and flows out from the evaporator (40) in a vapor phase.

Since the cross-sectional area of the refrigerant channel of the second intermediate header section (45) is reduced by the resistive hole (67) of the resistive plate portion (69), the quantity of refrigerant that flows through a portion of the refrigerant channel located downstream of the resistive plate portion (69) becomes relatively small, so that the quantity of refrigerant that flows through the refrigerant flow tube portions (50) connected to the portion of the refrigerant channel becomes relatively small. Accordingly, even when air-velocity distribution becomes nonuniform on the upstream side with respect to the air flow direction, and consequently air velocity drops in a region located rightward of the resistive plate portion (69), an extreme drop in the temperature of air having passed through the region can be prevented. Further, in the region where air velocity becomes low, freezing of condensed water on the surfaces of refrigerant flow tube portions and fins can be prevented.

When the resistive plate portion (69) is provided within the second intermediate header section (45), the velocity of refrigerant having passed through the resistive hole (67) of the resistive plate portion (69) increases. This causes difficulty for refrigerant to flow into the refrigerant flow tube portion (50) located in the vicinity of the resistive plate portion (69). However, provision of the guide portion (68) facilitates entry of refrigerant into the refrigerant flow tube portion (50) located in the vicinity of the resistive plate portion (69). As a result, uniformity can be established in terms of divided flow of refrigerant into the refrigerant flow tube portions (50) connected to a portion of the second intermediate header section (45) that is located downstream of the resistive plate portion (69). In Embodiment 2 described above, the resistive plate portion (69) is provided within the second intermediate header section (45), and the resistive hole (67) is formed in the resistive plate portion (69). However, the present invention is not limited thereto. A plurality of resistive plate portions may be provided within at least any one of refrigerant-flow-dividing header sections; i.e., at least one of the refrigerant inlet header section (42) and the second intermediate header section (45), while a resistive hole is formed in each of the resistive plate portions. Alternatively, at least one resistive plate portion may be provided within each of a plurality of refrigerant-flow- dividing header sections; i.e., each of the refrigerant inlet header section (42) and the second intermediate header section (45), while a resistive hole is formed in each of the resistive plate portions. In these cases, the resistive holes of different sizes may mixedly be present. Also, the resistive holes of different vertical positions within the corresponding refrigerant channels may mixedly be present.

INDUSTRIAL APPLICABILITY

The laminated heat exchanger according to the present invention is preferably used as, for example, an evaporator of a vehicle air conditioner, which is a refrigeration cycle on board a vehicle.

Claims

1. A laminated heat exchanger comprising a plurality of flat, hollow members, each of the flat, hollow members comprising two vertically elongated metal plates having perimetric edge portions joined together, a bulging refrigerant flow tube portion being formed between the two metal plates, a bulging header formation portion being connected to each of opposite ends of the refrigerant flow tube portion, the header formation portions of adjacent flat, hollow members arranged in a laminated condition being joined together, clearances between the refrigerant flow tube portions of adjacent flat, hollow members serving as air-passing clearances, the header formation portions of the flat, hollow members forming a refrigerant inlet header section having a refrigerant inlet, a refrigerant outlet header section having a refrigerant outlet, and a plurality of intermediate header sections, at least one of all the header sections serving as a refrigerant-flow-dividing header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction closed and which causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions, refrigerant flowing into the refrigerant inlet header section from the refrigerant inlet, flowing through the refrigerant flow tube portions and through the intermediate header sections, flowing into the refrigerant outlet header section, and. flowing out from the refrigerant outlet, wherein a resistive portion is provided in at least one of the refrigerant-flow-dividing header sections so as to impart resistance to refrigerant that flows through the refrigerant channel extending in a longitudinal direction of the refrigerant-flow-dividing header section.

2. A laminated heat exchanger according to claim 1, wherein the resistive portion comprises a resistive hole formed in a resistive plate portion that is provided within the refrigerant-flow-dividing header section in a manner to block the refrigerant channel thereof.

3. A laminated heat exchanger according to claim 2, wherein the resistive plate portion is a portion of a flat plate of metal sandwiched between and joined to two metal plates used to form the flat, hollow member, the portion of the flat plate being present within the refrigerant-flow-dividing header section; and a portion of the flat plate that is present in another header section having the refrigerant channel has a refrigerant passage hole formed therein and having a cross-sectional area equal to that of the refrigerant channel.

4. A laminated heat exchanger according to claim 2 or 3, wherein a plurality of resistive plate portions are provided within at least one refrigerant-flow-dividing header section, and the resistive hole is formed in each of the resistive plate portions.

5. A laminated heat exchanger according to claim 4, wherein the resistive holes of different sizes are mixedly present.

6. A laminated heat exchanger according to claim 4, wherein the resistive holes of different vertical positions within the corresponding refrigerant channels are mixedly present .

7. A laminated heat exchanger according to claim 2, wherein at least one resistive plate portion is provided within each of a plurality of refrigerant-flow-dividing header sections, and the resistive hole is formed in the resistive plate portion.

8. A laminated heat exchanger according to claim 7, wherein the resistive holes of different sizes are mixedly present .

9. A laminated heat exchanger according to claim 7, wherein the resistive holes of different vertical positions within the corresponding refrigerant channels are mixedly present .

10. A laminated heat exchanger according to Claim 2, wherein the size of the resistive hole is 1/60 to 1/10 the cross- sectional area of the refrigerant channel of the refrigerant- flow-dividing header section.

11. A laminated heat exchanger according to claim 2, wherein a guide portion is provided on a downstream-side surface of the resistive plate portion with respect to the refrigerant flow direction so as to guide refrigerant having passed through the resistive hole, toward the refrigerant flow tube portion near the resistive plate portion.

12. A laminated heat exchanger according to claim 1, wherein the flat, hollow member comprises the two vertically extending refrigerant flow tube portions spaced apart from each other in an air flow direction and the two header formation portions provided at each of the upper and lower end portions of the flat, hollow member, the two header formation portions being connected to corresponding upper ends of the two refrigerant flow tube portions and spaced apart from each other in the air flow direction, and the other two header formation portions being connected to corresponding lower ends of the two refrigerant flow tube portions and spaced apart from each other in the air flow direction.

13. A laminated heat exchanger according to claim 12 comprising a refrigerant inlet header section, a refrigerant outlet header section arranged upstream of the refrigerant inlet header section with respect to the air flow direction, a first intermediate header section arranged under the refrigerant inlet header section, a second intermediate header section arranged in tandem alignment with the first intermediate header section, a third intermediate header section arranged above the second intermediate header section and in tandem alignment with the refrigerant inlet header section, a fourth intermediate header section arranged upstream of the third intermediate header section with respect to the air flow direction and in tandem alignment with the refrigerant outlet header section, a fifth intermediate header section arranged under the fourth intermediate header section, and a sixth intermediate header section arranged under the refrigerant outlet header section and in tandem alignment with the fifth intermediate header section, wherein each of the refrigerant inlet header section, the first intermediate header section, the second intermediate header section, and the third intermediate header section comprises the header formation portions of the flat, hollow members located toward a downstream side with respect to the air flow direction; each of the refrigerant outlet header section, the fourth intermediate header section, the fifth intermediate header section, and the sixth intermediate header section comprises the header formation portions of the flat, hollow members located toward an upstream side with respect to the air flow direction; the refrigerant flow tube portions of the flat, hollow members establish communication between the refrigerant inlet header section and the first intermediate header section, communication between the second intermediate header section and the third intermediate header section, communication between the fourth intermediate header section and the fifth intermediate header section, and communication between the sixth intermediate header section and the refrigerant outlet header section; the third intermediate header section and the fourth intermediate header section communicate with each other via communication channels formed in the flat, hollow members; each of the refrigerant inlet header section, the second intermediate header section, and the sixth intermediate header section serves as a refrigerant-flow- dividing header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction closed and which causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions; each of the refrigerant outlet header section, the first intermediate header section, and the fifth intermediate header section serves as a refrigerant-flow- joining header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction open and which causes refrigerant flowing out from a plurality of refrigerant flow tube portions to join together; the refrigerant channel of the refrigerant inlet header section communicates with the refrigerant inlet; the refrigerant channel of the refrigerant outlet header section communicates with the refrigerant outlet; the refrigerant channel of the first intermediate header section communicates with that of the second intermediate header section; and the refrigerant channel of the fifth intermediate header section communicates with that of the sixth intermediate header section.

14. A laminated heat exchanger according to claim 1, wherein the flat, hollow member comprises a hairpin refrigerant flow tube portion, which comprises two vertically extending, bulging linear portions spaced apart from each other in the air flow direction and a bulging communication portion for establishing communication between the two bulging linear portions at upper ends thereof, and two header formation portions provided at the lower end portion of the flat, hollow member, the two header formation portions being connected to corresponding opposite ends of the refrigerant flow tube portion and spaced apart from each other in the air flow direction.

15. A laminated heat exchanger according to claim 14 comprising a refrigerant inlet header section, a refrigerant outlet header section arranged in tandem alignment with the refrigerant inlet header section, a first intermediate header section arranged downstream of the refrigerant inlet header section with respect to the air flow direction, and a second intermediate header section arranged downstream of the refrigerant outlet header section with respect to the air flow direction and in tandem alignment with the first intermediate header section, wherein each of the refrigerant inlet header section and the refrigerant outlet header section comprises the header formation portions of the flat, hollow members located toward an upstream side with respect to the air flow direction; each of the first intermediate header section and the second intermediate header section comprises the header formation portions of the flat, hollow members located toward a downstream side with respect to the air flow direction; the refrigerant flow tube portions of the flat, hollow members establish communication between the refrigerant inlet header section and the first intermediate header section and communication between the second intermediate header section and the refrigerant outlet header section; each of the refrigerant inlet header section and the second intermediate header section serves as a refrigerant- flow-dividing header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction closed and which causes refrigerant to dividedly flow into a plurality of refrigerant flow tube portions; each of. the refrigerant outlet header section and the first intermediate header section serves as a refrigerant-flow-joining header section which has a refrigerant channel allowing flow of refrigerant in the longitudinal direction thereof and having a downstream end with respect to the refrigerant flow direction open and which causes refrigerant flowing out from a plurality of refrigerant flow tube portions to join together; the refrigerant channel of the refrigerant inlet header section communicates with the refrigerant inlet; the refrigerant channel of the refrigerant outlet header section communicates with the refrigerant outlet; and the refrigerant channel of the first intermediate header section communicates with that of the second intermediate header section.

16. A refrigeration cycle comprising a compressor, a condenser, and an evaporator, the evaporator comprising a laminated heat exchanger according to any one of claims 1 to 15.

17. A vehicle having installed therein a refrigeration cycle according to claim 16 as a vehicle air conditioner.