U.S. patent application number 11/581738 was filed with the patent office on 2007-04-19 for evaporator.
This patent application is currently assigned to DENSO Corporation. Invention is credited to Norihide Kawachi, Tatsuhiko Nishino.
Application Number | 20070084589 11/581738 |
Document ID | / |
Family ID | 38000829 |
Filed Date | 2007-04-19 |
United States Patent
Application |
20070084589 |
Kind Code |
A1 |
Nishino; Tatsuhiko ; et
al. |
April 19, 2007 |
Evaporator
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.
Inventors: |
Nishino; Tatsuhiko;
(Obu-city, JP) ; Kawachi; Norihide; (Kariya-city,
JP) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
DENSO Corporation
Kariya-city
JP
|
Family ID: |
38000829 |
Appl. No.: |
11/581738 |
Filed: |
October 16, 2006 |
Current U.S.
Class: |
165/152 ;
165/176 |
Current CPC
Class: |
F28F 1/128 20130101;
F28F 17/005 20130101; F28D 2021/0071 20130101; F28D 1/05391
20130101 |
Class at
Publication: |
165/152 ;
165/176 |
International
Class: |
F28D 1/02 20060101
F28D001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 18, 2005 |
JP |
2005-303660 |
Claims
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
[0001] 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
[0002] 1. Field of the Invention
[0003] The present invention relates to an evaporator for a
refrigerant cycle device.
[0004] 2. Description of the Related Art
[0005] 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.
[0006] 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
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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
[0012] 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:
[0013] FIG. 1 is a perspective view showing an evaporator according
to a first embodiment of the present invention;
[0014] FIG. 2 is a perspective view showing a part of a core
portion of the evaporator according to the first embodiment;
[0015] FIG. 3 is a graph showing a condensed water amount generated
in an air flow direction of the evaporator according to the first
embodiment;
[0016] FIG. 4 is a schematic sectional view showing a structure of
the core portion;
[0017] FIG. 5 is a graph showing an air flow limit for generating
water scattering in evaporators of the first embodiment and
comparative examples;
[0018] FIG. 6 is a graph showing noise levels caused in evaporators
of the first embodiment and a comparative example at different
frequencies;
[0019] 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;
[0020] 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;
[0021] 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
[0022] 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
[0023] 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.
[0024] 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.
[0025] The evaporator 10 includes the core portion 13 and first and
second header tanks 2a, 2b. In the arrangement state of the
evaporator 10 shown in FIG. 1, the first header tank 2a is used as
an upper header tank, and the second header tank 2b 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 2a, 2b 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 2a, 2b are integrally fixed and fastened using a jig,
for example.
[0026] 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.
[0027] The tubes 5 are arranged in two layers in an air flow
direction, for example. The tubes 5 are constructed of first tubes
5a arranged at an upstream air side, and second tubes 5b arranged
at a downstream air side of the first tubes 5a 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
5b as in the refrigerant flow A in FIG. 2, and then flows through
the first tubes 5a as in the refrigerant flow B in FIG. 2.
[0028] 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 5a and 5b are lined in the air flow direction to have
a predetermined distance (predetermined space) therebetween.
Furthermore, plural pairs of the first and second tubes 5a and 5b
are arranged in the tube stacking direction, and the fin 4 is
located between the adjacent tubes 5a, 5b in the tube stacking
direction.
[0029] 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.
[0030] The first header tank 2a 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 2b 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 2a, 2b includes a tube insertion plate 7, a tank plate
9 and side plates 8.
[0031] 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.
[0032] 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 2a
is partitioned into four thank space parts, that is, a first tank
space part communicating with the second tubes 5b in the first
path, a second tank space part communicating with the second tubes
5b in the second path, a third tank space part communicating with
the first tubes 5a in the first path, and a fourth tank space part
communicating with the first tubes 5a in the second path. In
contrast, the inner space of the second header tank 2b is
partitioned into two tank space parts, that is, a first tank space
part communicating with all the second tubes 5b, and a second tank
space part communicating with all the first tubes 5a. Therefore,
refrigerant flowing through the tubes 5a, 5b can be U-turned,
respectively, in the first and second tank space parts of the
second header tank 2b.
[0033] 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 2a. 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.
[0034] As shown in FIG. 2, plural refrigerant passages are provided
in each of tubes 5 (tubes 5a, 5b) 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 2a to the tube insertion plate 7 of the second header
tank 2b. The fin 4 on one side of a pair of the tubes 5a, 5b in the
tube stacking direction is separated into a first fin part 4a, a
second fin part 4b and a third fin part 4b in the air flow
direction (core depth direction D in FIG. 1). As shown in FIG. 2,
the first fin part 4a is connected to the second fin part 4b by a
connection portion 18 having slits 18a, 18b, and the second fin
part 4b is connected to the third fin part 4c by a connection
portion 19 having slits 19a, 19b.
[0035] In this embodiment, a pair of the first tube 5a and the
second tube 5b are lined in the air flow direction to have the
predetermined space therebetween. Furthermore, the connection
portion 18 having the slits 18a, 18b is located at a position
outside of the first tube 5a, and the connection portion 19 having
the slits 19a, 19b is located at a position outside of the second
tube 5b. That is, the connection portions 18, 19 are provided at
positions in the air flow direction, where the first and second
tubes 5a, 5b 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 5a, 5b, in the air flow
direction. The slits 18a, 19a 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 5a, 5b. The slits 18b, 19b 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 18a, 18b in the tube stacking direction.
[0036] As shown in FIG. 2, the second fin part 4b is positioned at
the predetermined space portion between the first and second tubes
5a, 5b in the air flow direction, to extend from the first tube 5a
to the second tube 5b in the air flow direction. This fin structure
can be provided in both the fins 4 at two sides of the tubes 5a, 5b
in the tube stacking direction.
[0037] Because the first and second tubes 5a, 5b arranged in the
air flow direction are connected by the second fin part 4b, the
strength between the first and second tubes 5a, 5b can be
increased, thereby increasing the strength of the core portion 13
and the evaporator 10. Therefore, the second fin part 4b functions
as a bridge portion for connecting plural tubes (e.g., two tubes
5a, 5b in this embodiment) in the air flow direction.
[0038] Plural louvers 17 are provided in each of the first to third
fin parts 4a, 4b, 4c. As shown in FIG. 2, the louvers can be
partially not provided in an area of the second fin part 4b,
corresponding to the space portion between the first and second
tubes 5a, 5b in the air flow direction. In this case, the strength
for connecting the first and second tubes 5a, 5b using the second
fin part 4b can be further improved. However, the louvers 17 may be
uniformly provided in the second fin part 4b, similarly to the
first and third fin parts 4a, 4c.
[0039] Each of the first to third fins 4a, 4b, 4c is formed into
the wave shape extending from the first tank 2a to the second tank
2b in the tube longitudinal direction.
[0040] The evaporator 10 may be arranged such that the tubes 5 (5a,
5b) 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.
[0041] 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.
[0042] Therefore, when the slits 18a, 18b are provided at a
position X1 where X1/D is in a range between 0.25 and 0.5
(0.25.ltoreq.X1/D.ltoreq.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 18a, 18b are
provided at a position X1 where X1/D is in a range between 0.25 and
0.35 (0.25.ltoreq.X1/D.ltoreq.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 18a, 18b by its weight
without flying to the compartment together with the air flow.
[0043] Furthermore, when the slits 19a, 19b are provided at a
position X2 where X2/D is in a range between 0.5 and 0.75
(0.5.ltoreq.X2/D.ltoreq.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 19a, 19b are provided at a
position X2 where X2/D is in a range between 0.65 and 0.75
(0.65.ltoreq.X2/D.ltoreq.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 19a, 19b by its weight without flying to the
compartment together with the air flow.
[0044] Accordingly, in a case where 0.25.ltoreq.X1/D.ltoreq.0.35 in
the fin 4, about 50% of the condensed water generated on the
evaporator 10 can be drained through the slits 18a, 18b, 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 19a, 19b, and drain
performance of the evaporator 10 can be further improved. For
example, the dimension of each of slits 18a, 18b, 19a, 19b can be
set in a range of 0.5 mm-1.0 mm.
[0045] 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 5a, 5b 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).
[0046] 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).
[0047] Furthermore, when the slits 18a, 18b and the slits 19a, 19b
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.
[0048] 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 5b in the first path from
the first header tank 2a, and introduced into the second header
tank 2b. The refrigerant flowing into the second header tank 2b
from the second tubes 5b in the first path flows in the second
header tank 2b from the left side to the right side in FIG. 1, and
flows through the second tubes 5b in the second path from the
second header tank 2b. The refrigerant flowing into the first
header tank 2a from the second tubes 5b in the second path is
U-turned in the right part of the first header tank 2a in FIG. 1,
and then flows through the first tubes 5a in the second path. Then,
the refrigerant is introduced into the second header tank 2b from
the first tubes 5a in the second path, and flows in the upstream
air side part of the second header tank 2b from the right side to
the left side in FIG. 1. Thereafter, the refrigerant flows through
the first tubes 5a in the first path from the upstream air side
part of the second header tank 2b into the first header tank 2a, 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.
[0049] According to the first embodiment, the tubes 5 are
constructed of the plural first tubes 5a on the upstream air side
and the plural second tubes 5b on the downstream air side.
Furthermore, the first tube 5a and the second tube 5b are lined in
the air flow direction to have a predetermined space therebetween
in the air flow direction. The first tubes 5a and the second tubes
5b are connected to each other by the second fin part 4b without
having a slit recessed from the ridge portions. Therefore, the
strength for connecting the first and second tubes 5a, 5b 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.
[0050] Because the slits 18a, 18b, 19a, 19b 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 5a, 5b in the air flow direction, condensed water
generated on the evaporator 10 can be effectively drained
downwardly through the slits 18a, 18b, 19a, 19b. Therefore, the
amount of water flying into the compartment together with the air
flow can be reduced.
[0051] In each fin 4, the first fin part 4a is connected to the
second fin part 4b through the connection portion 18, and the
second fin part 4b is connected to the third fin part 4c through
the connection portion 19. Furthermore, the slits 18a, 18b, 19a,
19b 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.
[0052] The second fin part 4b 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 5a, 5b, 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 18a, 18b, 19a, 19b 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 5a, 5b.
[0053] In this embodiment, the fins 4 on both sides of the tubes
5a, 5b in the tube stacking direction are formed to have the same
structure having the first to third fins 4a, 4b, 4c. However, the
fins 4 on both sides of the tubes 5a, 5b may have different
structures. For example, the positions of the slits 18a, 18b, 19a,
19b in the air flow direction can be suitably changed in the fins
4. Furthermore, the first and second tubes 5a, 5b may be partially
connected in the air flow direction. Even in this case, by
connecting the second fin 4b to both the first and second tubes 5a,
5b, the strength of the core portion 13 can be further
increased.
[0054] Furthermore, in the first embodiment, any one of the slits
18a, 18b or the slits 19a, 19b 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 5a, 5b,
in the air flow direction. In addition, the open shapes of the
slits 18a, 18b and the slits 19a, 19b can be suitably changed.
Second Embodiment
[0055] 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.
[0056] The fin 22 fixed to the tubes 5a, 5b 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 2a to the second header tank 2b. Similarly to the
above-described first embodiment, plural fins 22 and the tubes 5
5a, 5b (5) are stacked alternately in the tube stacking direction
and are brazed to form a core portion.
[0057] 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 22a, a second fin part 22b
and a third fin part 22c by the first and second clearance portions
24, 25. The first clearance portion 24 is positioned in an area
where the first tubes 5a are positioned in the air flow direction,
and the second clearance portion 25 is positioned in an area where
the second tubes 5b are positioned in the air flow direction.
Therefore, the first and second tubes 5a, 5b are connected to each
other in the air flow direction by the second fin part 22b. That
is, the second fin part 22b functions as a bridge portion for
connecting the first and second tubes 5a, 5b in the air flow
direction. Therefore, the strength between the first and second
tubes 5a, 5b can be increased, thereby increasing the strength of
the core portion. Plural louvers are provided in the first to third
fin parts 22a, 22b, 22c. The second fin part 22b may be not
provided with the louvers at the portion corresponding to the space
portion between the first and second tubes 5a, 5b, in the air flow
direction. That is, the louvers may be not provided in the second
fin part 22b in an area corresponding to the non-refrigerant flow
portion between the first and second tubes 5a, 5b in the air flow
direction. In this case, the strength between the first and second
tubes 5a, 5b can be further increased.
[0058] 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.ltoreq.X1/D.ltoreq.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.ltoreq.X1/D.ltoreq.0.35), the
water draining performance can be more improved.
[0059] 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.ltoreq.X2/D.ltoreq.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.ltoreq.X2/D.ltoreq.0.75), the water draining performance
on the downstream air side can be more improved.
[0060] 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 5a and each of the second tubes 5b can be connected to each
other by the second fin part 22b, the strength of the core portion
can be increased, thereby reducing noise caused from the
evaporator.
Third Embodiment
[0061] 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 27a, 27b,
28a, 28b are provided at plural positions in the upstream air side
area of the fin 26, upstream from the space portion between the
tubes 5a, 5b in the air flow direction.
[0062] As shown in FIG. 8, the fin 26 is separated into first,
second and third fin parts 26a, 26b, 26c. Specifically, the first
and second fin parts 26a, 26b are partially separated from each
other by first slits 27a, 27b, and the second and third fin parts
26b, 26c are partially separated from each other by second slits
28a, 28b. The first and second fin parts 26a, 26b are connected to
each other by a first connection portion 27, and the second and
third fin parts 26b, 26c are connected to each other by a second
connection portion 28.
[0063] In this embodiment, the first tube 5a and the second tube 5b
are connected to each other in the air flow direction by the third
fin part 26c that extends from the second tube 5b to the first tube
5a in the fir flow direction. That is, the third fin part 26c
functions as a bridge portion for connecting the first tube 5a and
the second tube 5b in the air flow direction. Therefore, the
strength between the tubes 5a, 5b 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 26a,
26b, 26c. The third fin part 26c may be not provided with the
louvers at the portion corresponding to the space portion between
the first and second tubes 5a, 5b in the air flow direction. That
is, the louvers may be not provided in the third fin part 26c in an
area corresponding to the non-refrigerant flow portion between the
first and second tubes 5a, 5b in the air flow direction. In this
case, the strength between the first and second tubes 5a, 5b can be
increased.
[0064] The length of the first slit 27a from the ridge portion of
the fin 26, connected to one first tube 5a, can be set different
from the length of the first slit 27b from the ridge portion of the
fin 26, connected to an adjacent first tube 5a adjacent to the one
first tube 5a in the tube stacking direction. Similarly, the length
of the second slit 28a from the ridge portion of the fin 26,
connected to the one first tube 5a, can be set different from the
length of the second slit 28b from the ridge portion of the fin 26,
connected to the adjacent first tube 5a adjacent to the one first
tube 5a.
[0065] According to the third embodiment, the plural slits 27a,
27b, 28a, 28b are provided in the fin 26 in an upstream area, where
the first tubes 5a 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
[0066] 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 5a, 5b is different from that of the
above-described first embodiment. In the above-described first
embodiment, each of the tubes 5a, 5b is formed by pushing to have
plural refrigerant passages therein. However, in the fourth
embodiment, each of the tubes 5a, 5b is formed by bending a plate
member, and inner fins are provided in the tubes 5a, 5b, 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.
[0067] The tube structure of the fourth embodiment can be used for
the second or third embodiment.
Other Embodiments
[0068] 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.
[0069] For example, in the above-described embodiments, the first
tubes 5a on the upstream air side and the second tubes 5b 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 31a, 31b can be used
instead of the first and second tubes 5a, 5b in the above-described
embodiments. As shown in FIG. 10, the tube 31 includes the first
and second tube parts 31a, 31b 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 32a, 32b (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.
[0070] Alternatively, the inner space of the tube 5a, 5b may be not
need to be separated into plural refrigerant passages. That is, a
single refrigerant passage may be provided in each tube 5a, 5b.
[0071] In the above-described embodiments, two tubes (5a, 5b) 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 5a in the air flow direction can be made different to
the length of the second tube 5b 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.
[0072] 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.
[0073] Such changes and modifications are to be understood as being
within the scope of the present invention as defined by the
appended claims.
* * * * *