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Publication numberUS20070084589 A1
Publication typeApplication
Application numberUS 11/581,738
Publication dateApr 19, 2007
Filing dateOct 16, 2006
Priority dateOct 18, 2005
Publication number11581738, 581738, US 2007/0084589 A1, US 2007/084589 A1, US 20070084589 A1, US 20070084589A1, US 2007084589 A1, US 2007084589A1, US-A1-20070084589, US-A1-2007084589, US2007/0084589A1, US2007/084589A1, US20070084589 A1, US20070084589A1, US2007084589 A1, US2007084589A1
InventorsTatsuhiko Nishino, Norihide Kawachi
Original AssigneeDenso Corporation
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Evaporator
US 20070084589 A1
Abstract
In an evaporator, each fin is disposed between adjacent tubes in a tube stacking direction, and each of the tubes includes at least first and second tube parts lined to have a space therebetween in a flow direction of air passing between the adjacent tubes. The first tube part has therein a first refrigerant passage that is completely separately from a second refrigerant passage of the second tube part. Furthermore, the fin has at least one open portion that is opened from an end of the fin in the tube stacking direction to a predetermined portion, and the open portion is provided in the fin except for a position in the air flow direction, corresponding to the space. Therefore, the strength of the evaporator can be increased while condensed water on the evaporator can be effectively drained.
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Claims(18)
1. An evaporator comprising:
a plurality of passage members having therein refrigerant passages in which refrigerant flows, the passage members being arranged in a flow direction of air flowing outside of the passage members; and
a fin having a heat exchanging surface extending along the flow direction of air at a position adjacent to the passage members, wherein:
the fin has an open portion at a position adjacent to one of the refrigerant passages, and a bridge portion joined to the passage members; and
the passage members are connected to each other in the flow direction of air by the bridge portion.
2. The evaporator according to claim 1, wherein:
the fin includes a plurality of fin parts arranged in the flow direction of air;
the open portion is a slit opening provided between adjacent fin parts adjacent to each other in the flow direction of air;
the slip opening extends partially in the fin in a direction approximately perpendicular to the flow direction of air such that the fin has a connection portion between the fin pars; and
the bridge portion is one of the fin parts.
3. The evaporator according to claim 1, wherein:
the fin includes a plurality of fin parts arranged in the flow direction of air;
the open portion is a clearance opening that is provided between adjacent fin parts to separate the adjacent fin parts from each other in the flow direction of air; and
the bridge portion is one of the fin parts.
4. The evaporator according to claim 1, wherein:
the fin is a corrugated fin having a wave shape with ridge portions and flat surfaces;
the fin is joined to the passage members at the ridge portions; and
the open portion is opened from the ridge portions to predetermined positions of the flat surfaces.
5. The evaporator according to claim 1, wherein the bridge portion is a part of the fin, without having the open portion.
6. The evaporator according to claim 1, wherein the open portion is provided in the fin at a portion in the flow direction of air, except for an area corresponding to a space portion between the passage members in the flow direction of air.
7. The evaporator according to claim 1, wherein the open portion includes a plurality of openings provided in the fin at plural positions in the flow direction of air, except for an area corresponding to a space portion between the passage members in the flow direction of air.
8. The evaporator according to claim 1, wherein:
the open portion includes at least one of a first opening and a second opening provided in the fin;
the first opening is provided at a position separated from a most upstream end by a distance X1 in the flow direction of air;
the second opening is provided at a position separated from the most upstream end by a distance X2 in the flow direction of air; and
the distances X1 and X2 are set such that X1/D is in a range between the 0.25 and 0.5 and X2/D is in a range between 0.5 and 0.75 when an entire dimension of the fin in the flow direction of air is D.
9. The evaporator according to claim 8, wherein the distances X1 and X2 are set such that X1/D is in a range between the 0.25 and 0.35 and X2/D is in a range between 0.65 and 0.75.
10. The evaporator according to claim 1, further comprising:
a core portion including: a plurality of tubes stacked in a tube stacking direction, wherein each of the tubes includes the passage members lined in the flow direction of air; and a plurality of the fins each of which is located between adjacent tubes in the tube stacking direction; and
a tank portion extending a direction parallel to the tube stacking direction and connected to one end of each tube to communicate with each tube.
11. The evaporator according to claim 1, wherein each of the passage members has therein a plurality of refrigerant paths separated from each other, through which refrigerant flows in parallel with each other.
12. The evaporator according to claim 11, wherein the refrigerant paths of the passage member are formed by pushing.
13. The evaporator according to claim 1, wherein:
the fin is a corrugated fin having a wave shape with ridge portions and flat surface portions each of which is positioned between the ridge portions;
the fin is joined to outer surfaces of the passage members at the ridge portions;
each of the flat surface portions of the fin has a plurality of louvers; and
the open portion is opened from the ridge portions in the flat surface portions.
14. The evaporator according to claim 13, wherein:
the bridge portion is a part of the fin, without having the louvers and the open portion.
15. An evaporator comprising:
a plurality of tubes stacked in a stacking direction, wherein each of the tubes extends in a tube longitudinal direction;
a plurality of fins each of which is located between adjacent tubes in the stacking direction; and
a tank portion extending to the stacking direction to be connected to one longitudinal end of each tube, wherein:
each of the tubes includes at least first and second tube parts lined to have a space therebetween in a flow direction of air passing between the adjacent tubes, the flow direction of air being perpendicular to the stacking direction and the tube longitudinal direction;
the first tube part has therein a first refrigerant passage through which refrigerant flows;
the second tube part has therein a second refrigerant passage through which refrigerant flows, the second refrigerant passage being separate from the first refrigerant passage;
the fin extends from the first tube part to the second tube part in the flow direction of air, and has at least one open portion that is opened from an end of the fin in the stacking direction to a predetermined portion; and
the open portion is provided in the fin except for a position in the air flow direction, corresponding to the space.
16. The evaporator according to claim 15, wherein:
the fin continuously extends in the air flow direction as a single member; and
the open portion is opened from the end of the fin partially in the stacking direction.
17. The evaporator according to claim 15, wherein the open portion is opened and extends from the end of the fin to the other end of the fin in the stacking direction.
18. The evaporator according to claim 15, wherein the open portion has plural slit openings opened in the fin in areas except for the space in the flow direction of air.
Description
CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2005-303660 filed on Oct. 18, 2005, the contents of which are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an evaporator for a refrigerant cycle device.

2. Description of the Related Art

In a refrigerant evaporator for a refrigerant cycle device described in U.S. Pat. No. 6,308,527 (corresponding to JP-A-2000-179988), a fin pitch is set smaller in order to obtain a predetermined heat transferring area when the size of the evaporator is made small. However, when the fin pitch is made small, condensed water generated on the evaporator easily becomes in a water film shape on the outer surface of the evaporator by the surface tension between adjacent fin surfaces, thereby increasing a water amount staying on the outer surface of the evaporator. When the water amount staying on the evaporator is increased, the condensed water flows toward a downstream air side together with an air flow. Therefore, the condensed water may fly (scatter) into a compartment due to the air flow.

To reduce the water flying amount, clearance portions may be provided between adjacent fins at a position corresponding to a space portion between tube members, in the air flow direction, as described in U.S Pat. No. 6,308,527. However, in this structure of U.S. Pat. No. 6,308,527, the strength of the evaporator is reduced at positions where the clearance portions and drain water grooves are provided. Furthermore, in this evaporator, vibration noise due to a refrigerant flow may be easily caused.

SUMMARY OF THE INVENTION

In view of the foregoing problems, it is an object of the present invention to provide an evaporator which reduces a water flying amount from the surface of an evaporator while increasing the strength of the evaporator.

According to a first example of the present invention, an evaporator includes a plurality of passage members having therein refrigerant passages in which refrigerant flows, and a fin having a heat exchanging surface extending along the flow direction of air. The passage members are arranged in a flow direction of air flowing outside of the passage members, and the fin is located adjacent to the passage members in a direction perpendicular to the flow direction of air. Furthermore, the fin has an open portion opened at a position adjacent to the one of the refrigerant passages, and a bridge portion joined to the passage members. Therefore, the passage members are connected to each other in the flow direction of air by the bridge portion. Accordingly, water draining performance can be increased, thereby reducing a water flying amount flying toward a downstream air side together with the air flow. Because the passage members are connected to each other by the bridge portion, the strength between the passage members can be increased, thereby increasing the strength of the evaporator.

For example, the fin includes a plurality of fin parts arranged in the flow direction of air, the open portion is a slit opening provided between adjacent fin parts adjacent to each other in the flow direction of air, and the slip opening extends partially in the fin in a direction approximately perpendicular to the flow direction of air such that the fin has a connection portion between the fin pars. In this case, the bridge portion is one of the fin parts. Alternatively, the open portion is a clearance opening that is provided between adjacent fin parts to separate the adjacent fin parts from each other in the flow direction of air. Even in this case, the bridge portion may be used as one of the fin parts. Alternatively, the bridge portion may be a part of the fin, without having the open portion.

The open portion may be provided in the fin at a portion in the flow direction of air, except for an area corresponding to a space portion between the passage members in the flow direction of air. Alternatively, the open portion may include a plurality of openings provided in the fin at plural positions in the flow direction of air, except for an area corresponding to a space portion between the passage members in the flow direction of air.

According to a second example of the present invention, an evaporator includes: a plurality of tubes stacked in a stacking direction; a plurality of fins each of which is located between adjacent tubes in the stacking direction; and a tank portion extending to the stacking direction to be connected to one longitudinal end of each tube. In the evaporator, each of the tubes includes at least first and second tube parts lined to have a space therebetween in a flow direction of air passing between the adjacent tubes. Here, the flow direction of air is perpendicular to the stacking direction and a tube longitudinal direction. The first tube part has therein a first refrigerant passage through which refrigerant flows, the second tube part has therein a second refrigerant passage through which refrigerant flows, and the second refrigerant passage is separate from the first refrigerant passage. In addition, the fin extends from the first tube part to the second tube part, the fin has at least one open portion that is opened from an end of the fin in the stacking direction to a predetermined portion, and the open portion is provided in the fin except for a position in the air flow direction, corresponding to the space between the first and second tube parts. Accordingly, the water draining performance can be increased using the open portion, and strength of the evaporator can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments when taken together with the accompanying drawings. In the drawings:

FIG. 1 is a perspective view showing an evaporator according to a first embodiment of the present invention;

FIG. 2 is a perspective view showing a part of a core portion of the evaporator according to the first embodiment;

FIG. 3 is a graph showing a condensed water amount generated in an air flow direction of the evaporator according to the first embodiment;

FIG. 4 is a schematic sectional view showing a structure of the core portion;

FIG. 5 is a graph showing an air flow limit for generating water scattering in evaporators of the first embodiment and comparative examples;

FIG. 6 is a graph showing noise levels caused in evaporators of the first embodiment and a comparative example at different frequencies;

FIG. 7 is a schematic sectional view showing a structure of a core portion of an evaporator according to a second embodiment of the present invention;

FIG. 8 is a schematic sectional view showing a structure of a core portion of an evaporator according to a third embodiment of the present invention;

FIG. 9 is a schematic sectional view showing a structure of a core portion of an evaporator according to a fourth embodiment of the present invention; and

FIG. 10 is a perspective view showing a tube of an evaporator according to a modification of the first to fourth embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

The first embodiment will be now described with reference to FIGS. 1-6. An evaporator 10 of the first embodiment is generally used in a state shown in FIG. 1, and performs heat exchange between refrigerant flowing therein and air passing therethrough.

The evaporator 10 is a part of a refrigerant cycle device that is constructed with a compressor, a refrigerant radiator, an expansion valve, etc., together with the evaporator 10. Generally, refrigerant decompressed by the expansion valve flows into the evaporator 10 from a refrigerant inlet portion 1. The refrigerant flowing into the refrigerant inlet portion 1 flows through all refrigerant paths of the evaporator 10 as in the arrows shown in FIG. 1, and then flows out of the evaporator 10 through a refrigerant outlet portion 11. Refrigerant decompressed in the expansion valve is evaporated while passing through the refrigerant paths of the core portion 13 of the evaporator 10, so that evaporated gas refrigerant flows out of the refrigerant outlet portion 11.

The evaporator 10 includes the core portion 13 and first and second header tanks 2 a, 2 b. In the arrangement state of the evaporator 10 shown in FIG. 1, the first header tank 2 a is used as an upper header tank, and the second header tank 2 b is used as a lower header tank. Components of the evaporator 10, such as the core portion 13 and the first and second header tanks 2 a, 2 b are made of aluminum or an aluminum alloy, and are bonded together by brazing after those components are assembled. The components of the evaporator 10, such as the core portion 13 and the first and second header tanks 2 a, 2 b are integrally fixed and fastened using a jig, for example.

The core portion 13 includes a plurality of tubes 5 and a plurality of fins 4 which are stacked alternately in a stacking direction (i.e., the width direction W of the core portion 13, tank longitudinal direction). Side plates 3 each of which has approximately a U-shaped cross section are located at the outer ends of the core portion 13 in the width direction W, and are used as a strengthening member for improving the strength of the core portion 13.

The tubes 5 are arranged in two layers in an air flow direction, for example. The tubes 5 are constructed of first tubes 5 a arranged at an upstream air side, and second tubes 5 b arranged at a downstream air side of the first tubes 5 a in the air flow direction. As shown in FIGS. 1 and 2, refrigerant flowing into the refrigerant inlet portion 1 firstly flows through the second tubes 5 b as in the refrigerant flow A in FIG. 2, and then flows through the first tubes 5 a as in the refrigerant flow B in FIG. 2.

Each of the tubes 5 is a flat tube extending in a tube longitudinal direction approximately perpendicular to the air flow direction and the tube stacking direction. The flat tube 5 has a cross section having a major dimension in the air flow direction. Therefore, the flat tube 5 has side surfaces extending along the air flow direction. In this embodiment, a pair of the first and second tubes 5 a and 5 b are lined in the air flow direction to have a predetermined distance (predetermined space) therebetween. Furthermore, plural pairs of the first and second tubes 5 a and 5 b are arranged in the tube stacking direction, and the fin 4 is located between the adjacent tubes 5 a, 5 b in the tube stacking direction.

The fins 4 are joined and bonded to adjacent tubes 5 so that heat transferring performance between the refrigerant flowing in the tubes 5 and air passing through the core portion 13 between adjacent tubes 5 can be increased. The fin 4 is corrugated fin formed into a wave shape having ridge portions and flat surface portions. In the fin 4, each of the flat surface portions is positioned between adjacent ridge portions. The ridge portions of the fin 4 are joined to adjacent tubes 5 in the tube stacking direction, and the flat surfaces of the fin 4 extends along the air flow direction between the adjacent tubes 5. That is, as shown in FIGS. 2 and 4, the fin 4 is located between the adjacent tubes 5 to contact the adjacent tubes 5 at the ridge portions.

The first header tank 2 a is located at one longitudinal ends of the tubes 5 to communicate with the one longitudinal ends of the tubes 5, and the second header tank 2 b is located at the other longitudinal ends of the tubes 5 to communicate with the other longitudinal ends of the tubes 5. Each of the first and second header tanks 2 a, 2 b includes a tube insertion plate 7, a tank plate 9 and side plates 8.

The tube insertion plate 7 is formed into an approximately U shape having tube insertion holes into which the tubes 5 are inserted. The tank plate 9 is formed by pressing, and is joined to the tube insertion plate 7 to form a tank space between the tank plate 9 and the tube insertion plate 7. The side plates 8 are connected to two sides of the tank plate 9 and the tube insertion plate 7 in the tank longitudinal direction.

In this embodiment, the evaporator 10 is a two-path type in which opposite refrigerant streams are formed in the core portion 13 at two refrigerant path areas. For example, in this embodiment, one path is constructed by W/2 of the width dimension W of the core portion 13. Therefore, the inner space of the first header tank 2 a is partitioned into four thank space parts, that is, a first tank space part communicating with the second tubes 5 b in the first path, a second tank space part communicating with the second tubes 5 b in the second path, a third tank space part communicating with the first tubes 5 a in the first path, and a fourth tank space part communicating with the first tubes 5 a in the second path. In contrast, the inner space of the second header tank 2 b is partitioned into two tank space parts, that is, a first tank space part communicating with all the second tubes 5 b, and a second tank space part communicating with all the first tubes 5 a. Therefore, refrigerant flowing through the tubes 5 a, 5 b can be U-turned, respectively, in the first and second tank space parts of the second header tank 2 b.

A joint member 12 for forming the refrigerant inlet portion 1 and the refrigerant outlet portion 11 are provided at one end of the first header tank 2 a. For example, the refrigerant outlet portion 11 is provided at an upper portion in the joint member 12, and the refrigerant inlet portion 1 is provided at a lower portion of the refrigerant outlet portion 11 in the joint member 12. The refrigerant outlet portion 11 is coupled to a refrigerant suction side of the compressor, and the refrigerant inlet portion 1 is coupled to the expansion valve of the refrigerant cycle device.

As shown in FIG. 2, plural refrigerant passages are provided in each of tubes 5 (tubes 5 a, 5 b) to extend in the tube longitudinal direction. The fins 4 having the wave shapes are formed on both sides of each tube 5 in the tube stacking direction to be positioned from the tube insertion plate 7 of the first header tank 2 a to the tube insertion plate 7 of the second header tank 2 b. The fin 4 on one side of a pair of the tubes 5 a, 5 b in the tube stacking direction is separated into a first fin part 4 a, a second fin part 4 b and a third fin part 4 b in the air flow direction (core depth direction D in FIG. 1). As shown in FIG. 2, the first fin part 4 a is connected to the second fin part 4 b by a connection portion 18 having slits 18 a, 18 b, and the second fin part 4 b is connected to the third fin part 4 c by a connection portion 19 having slits 19 a, 19 b.

In this embodiment, a pair of the first tube 5 a and the second tube 5 b are lined in the air flow direction to have the predetermined space therebetween. Furthermore, the connection portion 18 having the slits 18 a, 18 b is located at a position outside of the first tube 5 a, and the connection portion 19 having the slits 19 a, 19 b is located at a position outside of the second tube 5 b. That is, the connection portions 18, 19 are provided at positions in the air flow direction, where the first and second tubes 5 a, 5 b are positioned. Therefore, the connection portions 18, 19 are not plated at the position adjacent to the predetermined space between the first and second tubes 5 a, 5 b, in the air flow direction. The slits 18 a, 19 a are opened from the ridge portions of the corrugated fin 4 to the connection portions 18, 19 in the flat surface portions of the corrugated fin 4, at one end side adjacent to a pair of the tubes 5 a, 5 b. The slits 18 b, 19 b are opened from the ridge portions of the corrugated fin 4 to the connection portions 18, 19 in the flat surface portions, at the other end side opposite to the slits 18 a, 18 b in the tube stacking direction.

As shown in FIG. 2, the second fin part 4 b is positioned at the predetermined space portion between the first and second tubes 5 a, 5 b in the air flow direction, to extend from the first tube 5 a to the second tube 5 b in the air flow direction. This fin structure can be provided in both the fins 4 at two sides of the tubes 5 a, 5 b in the tube stacking direction.

Because the first and second tubes 5 a, 5 b arranged in the air flow direction are connected by the second fin part 4 b, the strength between the first and second tubes 5 a, 5 b can be increased, thereby increasing the strength of the core portion 13 and the evaporator 10. Therefore, the second fin part 4 b functions as a bridge portion for connecting plural tubes (e.g., two tubes 5 a, 5b in this embodiment) in the air flow direction.

Plural louvers 17 are provided in each of the first to third fin parts 4 a, 4 b, 4 c. As shown in FIG. 2, the louvers can be partially not provided in an area of the second fin part 4 b, corresponding to the space portion between the first and second tubes 5 a, 5 b in the air flow direction. In this case, the strength for connecting the first and second tubes 5 a, 5 b using the second fin part 4 b can be further improved. However, the louvers 17 may be uniformly provided in the second fin part 4 b, similarly to the first and third fin parts 4 a, 4 c.

Each of the first to third fins 4 a, 4 b, 4 c is formed into the wave shape extending from the first tank 2 a to the second tank 2 b in the tube longitudinal direction.

The evaporator 10 may be arranged such that the tubes 5 (5 a, 5 b) extend approximately in a vertical direction, as shown in FIG. 1 and the major dimension of cross section of each tube 5 approximately corresponds to the air flow direction. Furthermore, an inner space of each tube 5 may be partitioned into plural passages extending in the tube longitudinal direction by pushing, or using a partition plate.

Next, the arrangement positions of the connection portions 18, 19 in the evaporator 10 will be described with reference to FIGS. 3 and 4. FIG. 3 shows a condensed water amount generated on the evaporator 10 at different positions in the air flow direction. In FIG. 3, X/D shows a relative position (distance) from the most upstream position of the fin 4 (core portion 13), when the most upstream position of the fin 4 in the air flow direction is 0, and the length from the most upstream position to the most downstream position of the fin 4 in the air flow direction is D as shown in FIG. 4. Therefore, X1, X2 in FIG. 3 correspond to the positions X1, X2 of the fin 4 in FIG. 4. As shown in FIG. 3, a large amount of the condensed water is generated at an upstream side in the air flow direction. Therefore, the amount of condensed water staying on the evaporator 10 is larger on the upstream air side than the downstream air side. Therefore, it is necessary to discharge the condensed water on the upstream air side in the evaporator 10, in order to effectively drain the condensed water.

Therefore, when the slits 18 a, 18 b are provided at a position X1 where X1/D is in a range between 0.25 and 0.5 (0.25≦X1/D≦0.5), the water draining performance can be effectively improved. Here, X1 is a position from the most upstream end of the fin 4 (core portion 13) in the air flow direction, and D is the entire dimension of fin 4 (core portion 14) in the air flow direction. Furthermore, when the slits 18 a, 18 b are provided at a position X1 where X1/D is in a range between 0.25 and 0.35 (0.25≦X1/D≦0.35), the water draining performance can be more improved. In this case, about 50% of the condensed water generated on the entire dimension D of the evaporator 10 can be drawn downwardly through the slits 18 a, 18 b by its weight without flying to the compartment together with the air flow.

Furthermore, when the slits 19 a, 19 b are provided at a position X2 where X2/D is in a range between 0.5 and 0.75 (0.5≦X2/D≦0.75), the water draining performance can be effectively improved on the downstream air side of the evaporator 10. Here, X2 is a position from the most upstream end of the fin 4 (core portion 13) in the air flow direction, and D is the entire dimension of fin 4 (core portion 13) in the air flow direction. Furthermore, when the slits 19 a, 19 b are provided at a position X2 where X2/D is in a range between 0.65 and 0.75 (0.65≦X2/D≦0.75), the water draining performance on the downstream air side of the evaporator 10 can be more improved. In this case, about 95% of the condensed water generated on the entire dimension D of the evaporator 10 can be drawn downwardly through the slits 19 a, 19 b by its weight without flying to the compartment together with the air flow.

Accordingly, in a case where 0.25≦X1/D≦0.35 in the fin 4, about 50% of the condensed water generated on the evaporator 10 can be drained through the slits 18 a, 18 b, thereby reducing the amount of the condensed water flowing to the downstream air side on the evaporator 10. Therefore, condensed water flowing from the position X1 to the position X2 can be quickly drained and removed through the slits 19 a, 19 b, and drain performance of the evaporator 10 can be further improved. For example, the dimension of each of slits 18 a, 18 b, 19 a, 19 b can be set in a range of 0.5 mm-1.0 mm.

FIG. 5 shows an air flow limit at which the water fly to the compartment is caused, and FIG. 6 shows a noise level at different frequencies (i.e., 1.6 kHz, 4.5 kHz, 8.0 kHz) In FIGS. 5 and 6, the comparative example 1 is an example where the first and second tubes 5 a, 5 b are connected at a tube connection portion in the air flow direction, and slits are provided in the fin 4 at the same position as the tube connection portion in the air flow direction (i.e., the structure of FIG. 9 of JP-A-2000-179988). In FIG. 5, the comparative example 2 is an example where slits are not provided in the fin 4 (i.e., the structure of FIG. 10 of JP-A-2000-179988).

As shown in FIG. 5, in the first embodiment, the air flow limit for causing the condensed water fly is large as compared with the comparative example 1 and the comparative example 2. Here, the air flow limit is a lowest air blowing amount (lowest air blowing level) at which the water fly is caused. Therefore, when the air flow limit is larger, the water fly is difficult to be caused. In the first embodiment, the air flow limit can be increased approximately by 0.7 m/s as compared with the comparative example 2, and is slightly larger than the comparative example 1. However, as shown in FIG. 6, in the first embodiment, the strength of the evaporator 10 is increased as compared with the comparative example 1, thereby the noise level can be largely decreased as compared with the comparative example 1 (e.g., by 4 dB-7 dB) at various frequencies (e.g., 1.6 KHz, 4.5 kHz, 8.0 kHz).

Furthermore, when the slits 18 a, 18 b and the slits 19 a, 19 b are provided in the fin 4 at plural positions (e.g., two positions) in the air flow direction, the air flow limit for causing the water fly can be further increased. In the example shown in FIG. 4, the air flow limit for causing the water fly can be increased by 0.1 m/s, as compared with the comparative example 1.

Next, operation of the evaporator 10 will be described. When the compressor is operated, refrigerant decompressed by the expansion valve flows into the evaporator 10 from the refrigerant inlet portion 1. The refrigerant flowing into the refrigerant inlet portion 1 flows through the second tubes 5 b in the first path from the first header tank 2 a, and introduced into the second header tank 2 b. The refrigerant flowing into the second header tank 2 b from the second tubes 5 b in the first path flows in the second header tank 2 b from the left side to the right side in FIG. 1, and flows through the second tubes 5 b in the second path from the second header tank 2 b. The refrigerant flowing into the first header tank 2 a from the second tubes 5 b in the second path is U-turned in the right part of the first header tank 2 a in FIG. 1, and then flows through the first tubes 5 a in the second path. Then, the refrigerant is introduced into the second header tank 2 b from the first tubes 5 a in the second path, and flows in the upstream air side part of the second header tank 2 b from the right side to the left side in FIG. 1. Thereafter, the refrigerant flows through the first tubes 5 a in the first path from the upstream air side part of the second header tank 2 b into the first header tank 2 a, so that the evaporated refrigerant is discharged from the refrigerant outlet portion 11 toward the refrigerant suction side of the compressor. Accordingly, air passing through the core portion 13 of the evaporator 10 can be cooled by evaporation latent heat while the refrigerant flows through the refrigerant paths in the evaporator 10 as in the arrows in FIG. 1.

According to the first embodiment, the tubes 5 are constructed of the plural first tubes 5 a on the upstream air side and the plural second tubes 5 b on the downstream air side. Furthermore, the first tube 5 a and the second tube 5 b are lined in the air flow direction to have a predetermined space therebetween in the air flow direction. The first tubes 5 a and the second tubes 5 b are connected to each other by the second fin part 4 b without having a slit recessed from the ridge portions. Therefore, the strength for connecting the first and second tubes 5 a, 5 b can be increased thereby increasing the strength of the evaporator 10. As a result, the variation due to the refrigerant flow can be reduced, and noise can be effectively reduced.

Because the slits 18 a, 18 b, 19 a, 19 b opened and recessed from the ridge portions of the fin 4 in the tube stacking direction are provided at positions corresponding to the refrigerant passages of the tubes 5 a, 5 b in the air flow direction, condensed water generated on the evaporator 10 can be effectively drained downwardly through the slits 18 a, 18 b, 19 a, 19 b. Therefore, the amount of water flying into the compartment together with the air flow can be reduced.

In each fin 4, the first fin part 4 a is connected to the second fin part 4 b through the connection portion 18, and the second fin part 4 b is connected to the third fin part 4 c through the connection portion 19. Furthermore, the slits 18 a, 18 b, 19 a, 19 b are formed from the ridge portions of the wave-shaped fin 4. Therefore, heat transferring surface area can be increased in the fin 4, and heat exchanging performance of the evaporator 10 can be increased using the fin 4.

The second fin part 4 b has a structure where a slit from the ridge portions is not provided. Furthermore, louvers are not provided partially in a middle area corresponding to the space portion between the first and second tubes 5 a, 5 b, where refrigerant does not flow. In this case, the strength of the core portion 13 can be further increased without reducing the heat exchanging performance. That is, the slits 18 a, 18 b, 19 a, 19 b are only provided in the fin 4 at positions corresponding to refrigerant flow areas in the air flow direction, where refrigerant flows in the tubes 5 a, 5 b.

In this embodiment, the fins 4 on both sides of the tubes 5 a, 5 b in the tube stacking direction are formed to have the same structure having the first to third fins 4 a, 4 b, 4 c. However, the fins 4 on both sides of the tubes 5 a, 5 b may have different structures. For example, the positions of the slits 18 a, 18 b, 19 a, 19 b in the air flow direction can be suitably changed in the fins 4. Furthermore, the first and second tubes 5 a, 5 b may be partially connected in the air flow direction. Even in this case, by connecting the second fin 4 b to both the first and second tubes 5 a, 5 b, the strength of the core portion 13 can be further increased.

Furthermore, in the first embodiment, any one of the slits 18 a, 18 b or the slits 19 a, 19 b may be provided in the fin 4 on the upstream air side or the downstream air side at a position other than the space portion between the first and second tubes 5 a, 5 b, in the air flow direction. In addition, the open shapes of the slits 18 a, 18 b and the slits 19 a, 19 b can be suitably changed.

Second Embodiment

The second embodiment of the present invention will be now described with reference to FIG. 7. In the second embodiment, a fin 22 is used instead of the fin 4 described in the first embodiment, and the other parts are similar to those of the above-described first embodiment. Here, the fin 22 is mainly described.

The fin 22 fixed to the tubes 5 a, 5 b is provided in air flow direction as shown in FIG. 7, and. is formed into a wave shape extending in the tube longitudinal direction from the first header tank 2 a to the second header tank 2 b. Similarly to the above-described first embodiment, plural fins 22 and the tubes 5 5 a, 5 b (5) are stacked alternately in the tube stacking direction and are brazed to form a core portion.

The fin 22 has first and second clearance portions 24, 25 each of which extends from one ridge portion of the wave-shaped fin 22 to another ridge portion of the wave-shaped fin 22 between adjacent tubes in the tube stacking direction. Therefore, the fin 22 is separated into a first fin part 22 a, a second fin part 22 b and a third fin part 22 c by the first and second clearance portions 24, 25. The first clearance portion 24 is positioned in an area where the first tubes 5 a are positioned in the air flow direction, and the second clearance portion 25 is positioned in an area where the second tubes 5 b are positioned in the air flow direction. Therefore, the first and second tubes 5 a, 5 b are connected to each other in the air flow direction by the second fin part 22 b. That is, the second fin part 22 b functions as a bridge portion for connecting the first and second tubes 5 a, 5 b in the air flow direction. Therefore, the strength between the first and second tubes 5 a, 5 b can be increased, thereby increasing the strength of the core portion. Plural louvers are provided in the first to third fin parts 22 a, 22 b, 22 c. The second fin part 22 b may be not provided with the louvers at the portion corresponding to the space portion between the first and second tubes 5 a, 5 b, in the air flow direction. That is, the louvers may be not provided in the second fin part 22 b in an area corresponding to the non-refrigerant flow portion between the first and second tubes 5 a, 5 b in the air flow direction. In this case, the strength between the first and second tubes 5 a, 5 b can be further increased.

The first clearance portion 24 can be provided at a position X1 in the air flow direction described in the first embodiment, and the second clearance portion 25 can be provided at a position X2 in the air flow direction described in the first embodiment. More specifically, the first clearance portion 24 can be provided at a position X1 where X1/D is in a range between 0.25 and 0.5 (0.25≦X1/D≦0.5). Accordingly, similarly to the first embodiment, the water draining performance can be effectively improved. Here, X1 is a position (distance) separated from the most upstream end of the fin 22 (core portion) in the air flow direction, and D is the entire dimension of the fin 22 (core portion) in the air flow direction. Furthermore, when the first clearance portion 24 is provided at a position X1 where X1/D is in a range between 0.25 and 0.35 (0.25≦X1/D≦0.35), the water draining performance can be more improved.

Furthermore, when the second clearance portion 25 can be provided at a position X2 where X2/D is in a range between 0.5 and 0.75 (0.5≦X2/D≦0.75), the water draining performance can be effectively improved on the downstream air side. Here, X2 is a position (distance) separated from the most upstream end of the fin 22 (core portion) in the air flow direction, and D is the entire dimension of the fin 22 (core portion) in the air flow direction. Furthermore, when the second clearance portion 25 is provided at a position X2 where X2/D is in a range between 0.65 and 0.75 (0.65≦X2/D≦0.75), the water draining performance on the downstream air side can be more improved.

According to the second embodiment, because the first and second clearance portions 24, 25 are provided, the water draining performance can improved thereby reducing the water flying amount together with the air flow. Furthermore, because each of the first tubes 5 a and each of the second tubes 5 b can be connected to each other by the second fin part 22 b, the strength of the core portion can be increased, thereby reducing noise caused from the evaporator.

Third Embodiment

The third embodiment of the present invention will be now described with reference to FIG. 8. In the third embodiment, a fin 26 is used instead of the fin 4 described in the first embodiment, and the other parts are similar to those of the above-described first embodiment. In the third embodiment, plural slits 27 a, 27 b, 28 a, 28 b are provided at plural positions in the upstream air side area of the fin 26, upstream from the space portion between the tubes 5 a, 5 b in the air flow direction.

As shown in FIG. 8, the fin 26 is separated into first, second and third fin parts 26 a, 26 b, 26 c. Specifically, the first and second fin parts 26 a, 26 b are partially separated from each other by first slits 27 a, 27 b, and the second and third fin parts 26 b, 26 c are partially separated from each other by second slits 28 a, 28 b. The first and second fin parts 26 a, 26 b are connected to each other by a first connection portion 27, and the second and third fin parts 26 b, 26 c are connected to each other by a second connection portion 28.

In this embodiment, the first tube 5 a and the second tube 5 b are connected to each other in the air flow direction by the third fin part 26 c that extends from the second tube 5 b to the first tube 5 a in the fir flow direction. That is, the third fin part 26 c functions as a bridge portion for connecting the first tube 5 a and the second tube 5 b in the air flow direction. Therefore, the strength between the tubes 5 a, 5 b can be increased thereby increasing the strength of the core portion of the evaporator. Plural louvers are provided in the first to third fin parts 26 a, 26 b, 26 c. The third fin part 26 c may be not provided with the louvers at the portion corresponding to the space portion between the first and second tubes 5 a, 5 b in the air flow direction. That is, the louvers may be not provided in the third fin part 26 c in an area corresponding to the non-refrigerant flow portion between the first and second tubes 5 a, 5 b in the air flow direction. In this case, the strength between the first and second tubes 5 a, 5 b can be increased.

The length of the first slit 27 a from the ridge portion of the fin 26, connected to one first tube 5 a, can be set different from the length of the first slit 27 b from the ridge portion of the fin 26, connected to an adjacent first tube 5 a adjacent to the one first tube 5 a in the tube stacking direction. Similarly, the length of the second slit 28 a from the ridge portion of the fin 26, connected to the one first tube 5 a, can be set different from the length of the second slit 28 b from the ridge portion of the fin 26, connected to the adjacent first tube 5 a adjacent to the one first tube 5 a.

According to the third embodiment, the plural slits 27 a, 27 b, 28 a, 28 b are provided in the fin 26 in an upstream area, where the first tubes 5 a are provided, in the air flow direction. Accordingly, the water draining performance can be effectively increased, thereby reducing the water flying amount flying together with the air flow.

Fourth Embodiment

The fourth embodiment of the present invention will be now described with reference to FIG. 9. In the fourth embodiment, the structure of the tubes 5 a, 5 b is different from that of the above-described first embodiment. In the above-described first embodiment, each of the tubes 5 a, 5 b is formed by pushing to have plural refrigerant passages therein. However, in the fourth embodiment, each of the tubes 5 a, 5 b is formed by bending a plate member, and inner fins are provided in the tubes 5 a, 5 b, so as to form plural refrigerant passages therein. In the fourth embodiment, the other parts can be made similar to those of the above-described first embodiment.

The tube structure of the fourth embodiment can be used for the second or third embodiment.

Other Embodiments

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art.

For example, in the above-described embodiments, the first tubes 5 a on the upstream air side and the second tubes 5 b on the downstream air side are formed separately from each other to have the space portion therebetween. However, as shown in FIG. 10, a tube 31 having first and second tube parts 31 a, 31 b can be used instead of the first and second tubes 5 a, 5 b in the above-described embodiments. As shown in FIG. 10, the tube 31 includes the first and second tube parts 31 a, 31 b that are lined in the air flow direction and are connected by a thin wall portion 32. The thin wall portion 32 is provided with opening holes 32 a, 32 b (space portion) which facilitate the water draining. Because the tube 31 is formed into an integrated member using the thin wall portion 32, the strength of the tube 31 can be increased, thereby increasing the strength of the core portion.

Alternatively, the inner space of the tube 5 a, 5 b may be not need to be separated into plural refrigerant passages. That is, a single refrigerant passage may be provided in each tube 5 a, 5 b.

In the above-described embodiments, two tubes (5 a, 5 b) are lined in the air flow direction; however, three or more tubes can be lined in the air flow direction. Furthermore, the length of the first tube 5 a in the air flow direction can be made different to the length of the second tube 5 b in the air flow direction. In addition, the slits or/and the clearance portions can be provided at plural positions more than two in the air flow direction.

In the above-described embodiments, the present invention is typically used for an evaporator of the refrigerant cycle device. However, the present invention can be used for a heat exchanger for other use, on which condensed water is generated when performing heat exchange.

Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.

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Classifications
U.S. Classification165/152, 165/176
International ClassificationF28D1/02
Cooperative ClassificationF28F1/128, F28F17/005, F28D2021/0071, F28D1/05391
European ClassificationF28F1/12D2, F28D1/053E6D, F28F17/00B
Legal Events
DateCodeEventDescription
Oct 16, 2006ASAssignment
Owner name: DENSO CORPORATION, JAPAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NISHINO, TATSUHIKO;KAWACHI, NORIHIDE;REEL/FRAME:018436/0825
Effective date: 20061006