U.S. patent application number 14/648209 was filed with the patent office on 2015-10-22 for fixing structure for heat exchanger.
This patent application is currently assigned to DENSO CORPORATION. The applicant listed for this patent is DENSO CORPORATION. Invention is credited to Tomoya ISHII, Akinori KUWAYAMA, Kenichiro MAEDA, Tatsuhiko NISHINO, Isao TAKADA.
Application Number | 20150300756 14/648209 |
Document ID | / |
Family ID | 50827419 |
Filed Date | 2015-10-22 |
United States Patent
Application |
20150300756 |
Kind Code |
A1 |
TAKADA; Isao ; et
al. |
October 22, 2015 |
FIXING STRUCTURE FOR HEAT EXCHANGER
Abstract
A heat exchanger has a rectangular parallelepiped shape in which
refrigerant flows. When sides configuring the heat exchanger having
the rectangular parallelepiped shape include a first side, a second
side, and a third side, a length of the third side is shortest. A
surface surrounded by the first side and the second side is a heat
exchange surface of the heat exchanger. A fixing structure for
fixing the heat exchanger to a case includes at least one fixing
portion disposed on at least one of a surface surrounded by the
first side and the third side and a surface surrounded by the
second side and the third side. The fixing portion is disposed at a
position where a composite vibration mode of not greater than 1000
Hz is minimum.
Inventors: |
TAKADA; Isao; (Chiryu-city,
JP) ; ISHII; Tomoya; (Miyoshi-city, JP) ;
NISHINO; Tatsuhiko; (Nagoya-city, JP) ; MAEDA;
Kenichiro; (Kariya-city, JP) ; KUWAYAMA; Akinori;
(Kariya-city, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENSO CORPORATION |
Kariya-city, Aichi |
|
JP |
|
|
Assignee: |
DENSO CORPORATION
Kariya-city, Aichi-pref.
JP
|
Family ID: |
50827419 |
Appl. No.: |
14/648209 |
Filed: |
October 21, 2013 |
PCT Filed: |
October 21, 2013 |
PCT NO: |
PCT/JP2013/006212 |
371 Date: |
May 28, 2015 |
Current U.S.
Class: |
165/76 |
Current CPC
Class: |
F28F 9/007 20130101;
B60H 1/00521 20130101; F28D 1/05391 20130101; F28D 2021/0085
20130101; F28D 2021/0071 20130101; F28F 2265/30 20130101 |
International
Class: |
F28F 9/007 20060101
F28F009/007 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 2012 |
JP |
2012-262209 |
Claims
1. A fixing structure for fixing a heat exchanger to a case, the
heat exchanger having a rectangular parallelepiped shape in which
refrigerant flows, when sides configuring the heat exchanger having
the rectangular parallelepiped shape include a first side, a second
side, and a third side, a length of the third side is shortest, a
surface surrounded by the first side and the second side is a heat
exchange surface of the heat exchanger, wherein the fixing
structure comprising: at least one fixing portion disposed on at
least one of a surface surrounded by the first side and the third
side and a surface surrounded by the second side and the third
side, wherein the fixing portion is disposed at a position where a
composite vibration mode of not greater than 1000 Hz is minimum,
except for four corners of the heat exchange surface and except for
a position corresponding to an antinode part of a natural vibration
mode of the heat exchanger.
2.-4. (canceled)
5. The fixing structure according to claim 1, wherein the fixing
portion is disposed at the position where a frequency of a
vibration mode of the heat exchanger is different from a natural
frequency of a wall surface of the case.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2012-262209 filed on Nov. 30, 2012, the disclosure of which is
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a fixing structure for a
heat exchanger in which refrigerant flows.
BACKGROUND ART
[0003] Patent literature 1 describes a cooling evaporator in an air
conditioning unit for a vehicle, and the cooling evaporator is
mounted in an air conditioning unit case through elastic members at
four corners of the evaporator. The elastic member absorbs
vibration of the evaporator. When the vibration absorbing action
will be described in more detail, the evaporator is coupled with a
compressor in an engine compartment of the vehicle through a
refrigerant piping, and the compressor is fitted to an engine of
the vehicle and driven by the engine. For that reason, the
compressor vibrates integrally with the engine. The compressor per
se vibrates due to pulsation generated when the compressor
discharges refrigerant. The vibration of the compressor propagates
to the evaporator located within the vehicle interior through the
refrigerant piping. Under the circumstances, the evaporator is
supported by the elastic members whereby the vibration propagated
to the evaporator is absorbed by the elastic members. The vibration
of the evaporator is restrained from being transmitted to the air
conditioning unit case, amplified, and becoming an abnormal noise
(noise).
[0004] Patent literature 2 describes a heat exchanger in an air
conditioning apparatus for a vehicle, in which non-passage
components other than refrigerant passage are supported by a case.
Since the non-passage components do not configure a flow path for
heat exchange medium unlike the passage forming components, the
non-passage components are not vibrated directly by the pulsation
of the heat exchange medium, and also not vibrated directly by
collision of the heat exchange medium. When the case supports
portions not directly vibrated, the vibration of the heat exchanger
is hard to be transmitted to the case.
PRIOR ART LITERATURES
Patent Literature
[0005] Patent Literature 1: JP 2006-335189 A [0006] Patent
Literature 2: JP 2012-1124 A
SUMMARY OF INVENTION
[0007] In the conventional art described in Patent literature 1,
the elastic members intervene at the four corners. However, the
elastic members mounted to the case of the evaporator increase the
number of components producing the evaporator. This leads to an
increase in the number of processes for manufacturing the
evaporator, and leads to a reduction in the productivity.
[0008] In the conventional art described in Patent literature 2,
the heat exchanger is constructed integrally with the non-passage
components and the passage forming components while the non-passage
components are supported. If the passage forming components
vibrate, the vibration also propagates to the non-passage
component. As a result, the effect of suppressing the transmission
of the vibration is small, since the vibration propagates to the
case.
[0009] The present disclosure aims at providing a fixing structure
for a heat exchanger which is capable of reducing transmission of
vibration to an external with a simple configuration.
[0010] According to the present disclosure, at least one fixing
portion for being fixed to a case is disposed on at least one of a
surface surrounded by a first side and a third side and a surface
surrounded by a second side and the third side. In the fixing
structure for a heat exchanger, the fixing portion is disposed at a
position except for four corners of a heat exchange surface and
except for a position corresponding to an antinode part of a
natural vibration mode of the heat exchanger.
[0011] According to the present disclosure, the heat exchanger is
fixed to the case disposed to the external. At least one fixing
portion for being fixed to the case is disposed on at least one of
the surface surrounded by the first side and the third side and the
surface surrounded by the second side and the third side. Further,
the fixing portion is disposed at the position except for the four
corners of the heat exchange surface, and the position is also a
position (hereinafter referred to as "position except for an
antinode part") except for a position corresponding to an antinode
part of a natural vibration mode of the heat exchanger. It is
difficult to vibrate at the position except for the four corners
and except for the antinode part. In other words, the largest
vibration occurs at the antinode part, and it is found by extensive
research results of the applicant that the four corners are also
positions to be liable to vibrate as with the antinode part. Since
the fixing portion is disposed avoiding the position to be liable
to vibrate, the heat exchanger is fixed to the case at a portion
difficult to vibrate. This makes it difficult to propagate the
vibration of the heat exchanger from the fixing portion to the
case. The vibration from the heat exchanger to the case can be
suppressed with a simple configuration to change the position of
the fixing portion. As a result, noise caused by vibration
transmitted to the case from the heat exchanger can be
suppressed.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a perspective view illustrating an evaporator
according to a first embodiment.
[0013] FIG. 2 is a diagram illustrating vibrating state in
respective natural vibration modes.
[0014] FIG. 3 is a graph showing an amplitude in a longitudinal
direction.
[0015] FIG. 4 is a front view illustrating a simplified
evaporator.
[0016] FIG. 5 is a graph showing a relationship between a frequency
and an inertance.
[0017] FIG. 6 is a graph showing a total inertance within a
frequency band.
[0018] FIG. 7 is a front view illustrating an air conditioning
apparatus for a vehicle according to a second embodiment.
[0019] FIG. 8 is a graph showing an amplitude in a width
direction.
[0020] FIG. 9 is a front view illustrating an evaporator according
to a third embodiment.
[0021] FIG. 10 is a front view illustrating an evaporator according
to a fourth embodiment.
DESCRIPTION OF EMBODIMENTS
[0022] Hereinafter, multiple embodiments for embodying the present
disclosure will be described with reference to the drawings. In
each embodiment, parts corresponding to matters described in a
preceding embodiment may be denoted by identical reference marks,
or one character may be added to a preceding reference mark for
abbreviating repetitive description. When a part of the
configuration in the respective embodiments is described, other
parts of the configuration are the same as those in the embodiment
described precedently. Not only the combination of parts described
specifically in the respective embodiments, but also the partial
combination of the respective embodiments can be performed
particularly if there is no harm in the combination.
First Embodiment
[0023] A first embodiment of the present disclosure will be
described with reference to FIGS. 1 to 6. An evaporator 10 is a
heat exchanger arranged in a refrigeration cycle not shown, in
which refrigerant is compressed by a compressor to have high
temperature and high pressure and is cooled by a radiator through
heat radiation. Further, refrigerant is depressurized by a
depressurizing device to have low temperature and low pressure, and
the refrigerant is evaporated by the evaporator 10. As illustrated
in FIG. 1, the evaporator 10 according to this embodiment includes
a core portion 11, an upper tank unit 12, and a lower tank unit 13.
The respective components are brazed to each other.
[0024] The core portion 11 is configured by alternately stacking
multiple flat tubes 14 and multiple corrugated fins 15 on each
other. A side plate 16 is arranged outside of the outermost
corrugated fins 15 on both sides in a stacking direction thereof
(X-direction in FIG. 1). A refrigerant which is an inner fluid of
the core portion 11 flows along a longitudinal direction
(Y-direction in FIG. 1) of the flat tubes 14. When it is assumed
that a flowing direction of the refrigerant is a width direction Y
of the evaporator 10, a ventilation direction in the core portion
11 is a thickness direction Z of the evaporator 10, and a direction
(stacking direction) orthogonal to the width direction Y and the
thickness direction Z is a longitudinal direction X of the
evaporator 10. The evaporator 10 is arranged in a vehicle by
setting the width direction Y as a vertical direction.
[0025] The flat tubes 14 are pipe members formed by bending a thin
aluminum strip plate, and the cross-section orthogonal to the
refrigerant flowing direction is formed in a flat shape. The flat
tubes 14 may integrally define multiple refrigerant passages
extending in the longitudinal direction through extrusion molding
of an aluminum material. Alternatively, two metal thin plates made
of aluminum may be joined together to have a hollow shape. A
thickness of the flat tube 14 is, for example, 0.2 mm.
[0026] The corrugated fin 15 is formed by subjecting a thin
aluminum strip plate having both surfaces on which a brazing filler
metal is cladded in advance to roller processing in a meandering
shape (wave shape). The corrugated fin 15 has multiple louvers (not
shown) formed by cutting and bending for enhancing the heat
exchange efficiency. A thickness of the corrugated fin 15 is, for
example, 0.05 mm.
[0027] The side plate 16 is configured as reinforcing member on the
core portion 11. The side plate 16 is formed by pressing an
aluminum plate material that is a bare material on which a brazing
filler metal is not cladded. Both ends of the side plate 16 in a
longitudinal direction (width direction Y) are formed in a planar
shape. A center portion of each side plate 16 is formed to have a
U-shaped cross-section opened outward in the stacking direction of
the flat tubes 14 and the corrugated fins 15. The side plate 16 is
brazed to the corrugated fin 15. A thickness of the side plates 16
is, for example, 1 mm.
[0028] The upper tank unit 12 is divided into two in a longitudinal
direction of the flat tube 14 to include a header plate adjacent to
the flat tube and a header tank away from the flat tube. Each of
the header tank and the header plate has a semi-circular or
rectangular cross-sectional shape, and is formed by pressing an
aluminum flat material.
[0029] A brazing filler metal is cladded on both surfaces of the
header tank and an inner surface of the header plate in advance.
The header tank and the header plate are fitted to each other, and
brazed to form a cylindrical body in which two internal spaces are
aligned in the flowing direction of the blowing air (thickness
direction Z of the evaporator 10). A cap shaped by subjecting an
aluminum flat material to press processing is brazed to an opening
portion defined at an end of the upper tank unit 12 in a
longitudinal direction thereof (both ends in the longitudinal
direction X), thereby closing the opening portion. The thickness of
the upper tank unit 12 and the lower tank unit 13 is, for example,
1 mm.
[0030] Further, two separators (not shown) are brazed substantially
in the center of the upper tank unit 12 in the longitudinal
direction X, and separate the respective internal spaces in the
longitudinal direction of the upper tank unit 12 (longitudinal
direction X of the evaporator 10). The two internal spaces of the
upper tank unit 12 arrayed in the flowing direction of the blowing
air communicate with each other through multiple communication
passages not shown, in a region of the upper tank unit 12 on a
right side of the separator.
[0031] The lower tank unit 13 has a structure similar to that of
the upper tank unit 12, and forms a cylindrical body including a
header tank and a header plate. A cap is provided at an opening
portion on both ends thereof in the longitudinal direction. Unlike
the upper tank unit 12, configurations corresponding to the
separator and the communication passage are not provided in the
lower tank unit 13.
[0032] A flat tube insertion port not shown and a side plate
insertion port not shown are provided in a wall surface (wall
surface of the header plate) of the upper and lower tank units
adjacent to the core portion 11 at the same pitches as pitches of
the flat tubes 14 and the side plates 16 in the longitudinal
direction X. The end of the flat tube 14 in the longitudinal
direction and the end of the side plate 16 in the longitudinal
direction are inserted into the respective insertion ports, and
brazed. With the above configuration, the flat tube 14 communicates
with the internal space of the upper and lower tank unit 12, 13,
and the ends of the side plate 16 in the longitudinal direction are
supported and fixed to the upper and lower tank units 12 and 13
respectively.
[0033] A connection block 17 (refrigerant outlet/inlet part) is
brazed to a left side end of the upper tank unit 12 in FIG. 1, and
has an inlet port 18 into which refrigerant flows and an outlet
port 19 out of which refrigerant flows. Of the internal spaces of
the upper tank unit 12, the inlet port 18 communicates with inside
of the tank unit 12a on the downstream side in the air flow in FIG.
1 and the outlet port 19 communicates with inside of the tank unit
12b on the upstream side in the air flow in FIG. 1.
[0034] The flat tubes 14 are arrayed in two rows so that the
upstream flat tube row and the downstream flat tube row are aligned
in a flow of blowing air which is an external fluid, in
correspondence with the array of the upper and lower tank unit 12,
13. In the evaporator 10 formed as described above, after
refrigerant flows into the tank unit 12a from the inlet port 18 on
the downstream side of the upper tank unit 12 in the air flow, the
refrigerant makes a U-turn vertically and flows in the downstream
flat tube row, and returns to a right region of the upper tank unit
12 in FIG. 1. The refrigerant flows from the upper tank unit 12a
(right tank unit) on the downstream side in the air flow into the
upper tank unit 12b (right tank unit) on the upstream side in the
air flow. The refrigerant passes through the upstream flat tube
row, makes a U-turn vertically in the same manner, and returns to
the upper tank unit 12b on the upstream side in the air flow. Then,
the refrigerant finally flows out of the outlet port 19. During
this operation, the evaporator 10 evaporates the refrigerant,
thereby cooling the blowing air by latent heat of evaporation.
[0035] A fixing structure of the evaporator 10 will be described.
The evaporator 10 is fixed into an air conditioning case
configuring an air conditioning apparatus for a vehicle. The air
conditioning case (not shown) includes an air ventilation passage
therein, and an outside air inlet port and an inside air inlet port
which are air intake ports are provided on one side of the
ventilation passage. A blowing opening is defined on the other side
of the ventilation passage, and the conditioned air is blown into
the vehicle interior from the blowing opening. The air conditioning
case is formed of multiple case members, and a material of the case
member is, for example, a resin molded product such as
polypropylene.
[0036] The evaporator 10 is arranged to cross the overall
ventilation passage in the air conditioning case, and all of the
blown air passes through the evaporator 10. The evaporator 10
described above functions as a heat exchanger that cools the blown
air before flowing into a cold air passage by absorbing heat by the
refrigerant flowing in the evaporator 10 during cooling
operation.
[0037] As illustrated in FIG. 1, the evaporator 10 has a
rectangular parallelepiped shape. When the evaporator 10 is viewed
as the rectangular parallelepiped shape, it is assumed that a side
of the evaporator 10 extending in the longitudinal direction X is a
first side 31, a side of the evaporator 10 extending in the width
direction Y is a second side 32, and a side of the evaporator 10
extending in the thickness direction Z is a third side 33. In this
embodiment, a length of the first side 31 is longest, and a length
of the third side 33 is shortest. Since a surface surrounded by the
first side 31 and the second side 32 configures a surface of the
core portion 11 and corresponds to a heat exchange surface 11a in
which heat is exchanged between the refrigerant and the air.
[0038] In this embodiment, a fixing structure of the evaporator 10
is configured by focusing attention on noise caused by vibration
propagation from the evaporator 10 to the air conditioning case
which is one of noise causes. Specifically, in order to suppress
the vibration propagation from the evaporator 10 to the air
conditioning case, attention is focused on the natural vibration
mode of the evaporator 10 to configure the fixing structure.
[0039] The noise caused by the propagation from the evaporator 10
to the air conditioning case is restricted to 1000 Hz or lower. As
illustrated in FIGS. 2 and 3, the evaporator 10 has the natural
vibration mode in that frequency band, and the vibration manner is
different depending on the vibration mode. In FIG. 3, a first order
mode corresponds to 215 Hz. Likewise, a second order mode
corresponds to 241 Hz, a third order mode corresponds to 367 Hz, a
fourth order mode corresponds to 677 Hz, and a fifth order mode
corresponds to 865 Hz. The axis of ordinate in FIG. 2 represents a
dimensionless value with the maximum value of an amplitude as 1,
which is called "vibration level". The deflection illustrated in
FIG. 2 is caused by the shape of the evaporator 10 regardless of
physical properties.
[0040] The vibration exciting force of the vibration mode (sum of
the vibration modes) is represented in FIG. 3, in portions where
the amplitude is larger and portions where the amplitude is smaller
are present on upper and lower sides, on front and rear sides, and
on right and left sides. In order words, if a portion smallest in
the sum of the vibration modes is held, the vibration transmission
from the evaporator 10 to the air conditioning case can be
minimized. Hereinafter, the large amplitude may be called
"antinode" and the small amplitude may be called "node".
[0041] In a conventional art, as indicated by imaginary lines 21 in
FIG. 4, the evaporator 10 is held at four corners (square corners).
In this holding method, because the antinode in the evaporator 10
is held, the vibration transmission from the evaporator 10 to the
air conditioning case becomes large, and a reduction in NV (noise
vibration) is insufficient. Therefore, in this embodiment, in order
to reduce the NV, a structure is required to hold positions
indicated by dashed lines 22 illustrated in FIG. 4.
[0042] Specifically, a fixing portion 30 for being fixed to at
least one case is disposed on at least one of a surface surrounded
by the first side 31 and the third side 33 (hereinafter also called
"upper and lower surfaces") and a surface surrounded by the second
side 32 and the third side 33 (hereinafter also called "right and
left surfaces"). In this embodiment, of the upper and lower
surfaces, two fixing portions 30 are disposed on the lower surface.
As shown in FIGS. 1 and 4, the fixing portion 30 is present at a
position except for the four corners in the heat exchange surface
11a of the evaporator 10 and except for a position corresponding to
the antinode part (refer to FIG. 3) in the natural vibration mode
of the evaporator 10. Therefore, the fixing portion 30 is arranged
by avoiding center and both ends (four corners) of the first side
31. In other words, the fixing portion 30 is present at a position
except for the above-mentioned four corners, such that the
amplitude of the natural vibration mode of the evaporator 10 is
smaller at the position than at the four corners.
[0043] Further, when a length of the first side 31 is defined as L,
a preferable position of the fixing portion 30 is preferably a
position apart by 0.25 L.+-.0.05 L and a position apart by 0.75
L.+-.0.05 L, from an end of the first side 31. In the present
specification, 0.25 L means 0.25.times.L, and a case in which
numbers and L are continuously described has the same manner
meaning. In other words, the fixing portion 30 is disposed on at
least one of a range of 0.2 L to 0.3 L and a range of 0.7 L to 0.8
L from the end of the first side 31. The positions of the fixing
portion 30 correspond to regions surrounded by imaginary lines in
FIG. 3. In other words, the fixing portion 30 is provided at the
(so-called node) position where the composite vibration mode of not
greater than 1000 Hz is minimum
[0044] The fixing portion 30 is defined by a protrusion portion
protruding downward from the lower tank unit 13. The evaporator 10
is fixed to the air conditioning case in a state where the fixing
portion 30 is pressed against an inner wall of the air conditioning
case. An elastic member such as rubber is interposed between the
fixing portion 30 and the air conditioning case. With the
interposition of an elastic member, the vibration transmitted from
the fixing portion 30 to the air conditioning case can be more
attenuated. The evaporator 10 comes in contact with the air
conditioning case in a portion other than the fixing portion 30,
but is fixed to the air conditioning case at the fixing portion 30
to transmit the vibration. Therefore, the other contact portions
come in contact with the air conditioning case to the degree of
merely supporting the evaporator 10.
[0045] The fixing portion 30 is disposed at a position where a
frequency of the vibration mode of the evaporator 10 is different
from a natural frequency of a wall surface of the air conditioning
case. The natural frequency of the air conditioning case is
different depending on a location. If the fixing portion 30 is
disposed at the position where the natural frequency of the air
conditioning case is the same as the frequency of the vibration
mode of the evaporator 10, even while the vibration transmitted
from the evaporator 10 is attenuated, the air conditioning case
largely vibrates. This is because the effect of reducing the NV
becomes small.
[0046] Subsequently, experimental results will be described, which
are obtained by comparing the fixing structure of the evaporator 10
according to this embodiment with a fixing structure of a
comparative example. In the fixing structure of the embodiment, the
evaporator 10 is fixed at the positions of 0.25 L and 0.75 L at
each of the upper tank unit 12 and the lower tank unit 13. In the
fixing structure of the comparative example, the evaporator is
fixed at the four corners.
[0047] In experimenting, an expansion valve in addition to the
evaporator are mounted to an air conditioning apparatus for a
vehicle, and vibration is excited in the thickness direction Z
relative to the expansion valve at nine kinds of respective
frequencies shown in FIG. 5, that is, 160 Hz, 200 Hz, 250 Hz, 315
Hz, 400 Hz, 500 Hz, 630 Hz, 800 Hz, and 1000 Hz. In vibrating,
Shaker (product name: integral shaker made by LMS International
n.v.) is used.
[0048] The inertance is detected at a contact portion of the air
conditioning case with the fixing portion 30 as a detection
position by using a piezoresistive vibration acceleration sensor
(Model No. 352C22 made by PCB). The experimental conditions in
FIGS. 5 and 6 are identical with each other. FIG. 5 illustrates the
inertances at the respective frequencies, and FIG. 6 illustrates a
total of the inertances at 200 Hz to 1 kHz.
[0049] As illustrated in FIG. 5, it is found that the inertance is
smaller in the embodiment than that is in the comparative example
at all the frequencies. As a result, it is found that the effect of
reducing the NV is larger in the embodiment compared with the
comparative example. As illustrated in FIG. 6, the total of the
inertances at 200 Hz to 1 kHz is smaller in the embodiment.
Therefore, it is found that the effect of reducing the NV is larger
in the embodiment compared with the comparative example. As is
understood from FIGS. 5 and 6, it is apparent that the fixing
structure of the evaporator 10 according to this embodiment has the
effect of reducing the NV.
[0050] As described above, the evaporator 10 according to this
embodiment is fixed to the air conditioning case disposed
externally. Two fixing portions 30 for fixing the evaporator 10 to
the air conditioning case are disposed on the surface surrounded by
the first side 31 and the third side 33. Further, the fixing
portion 30 is disposed at the position except for the four corners
of the heat exchange surface 11a and except for the position
corresponding to the antinode part of the natural vibration mode of
the evaporator 10. The position except for the four corners and the
antinode part is a position where vibration is difficult. In other
words, the antinode part is the position that most vibrates, and
the four corners are also liable to vibrate. Since the fixing
portion 30 is provided with the avoidance of the positions where
the vibration is easily generated, the evaporator is fixed to the
air conditioning case at portions difficult to vibrate. This makes
it difficult to transmit the vibration of the evaporator 10 to the
air conditioning case through the fixing portion 30. With a simple
configuration to change the position of the fixing portion 30, the
vibration transmission from the evaporator 10 to the air
conditioning case can be suppressed. As a result, the noise caused
by vibration of the air conditioning case can be suppressed while
the evaporator 10 vibrates.
[0051] In this embodiment, preferably, the fixing portion 30 is
disposed at the position except for the four corners of the heat
exchange surface 11a such that the amplitude of the natural
vibration mode of the heat exchanger is smaller at the position
than the amplitude at the four corners. When the evaporator is
fixed at the position smaller in the amplitude than the four
corners, the vibration transmitted to the air conditioning case can
be suppressed compared with the conventional art where the
evaporator is fixed at the four corners. As a result, the effect of
reducing the NV can be achieved.
[0052] The position at which the fixing portion 30 is disposed is
more preferably a position at which the composite vibration mode of
not greater than 1000 Hz becomes minimum. The noise caused by the
propagation from the evaporator 10 to the air conditioning
apparatus for a vehicle is limited to 1000 Hz or lower. Therefore,
the evaporator is fixed at the position where the composite
vibration mode of not greater than 1000 Hz is minimum, thereby
being capable of further suppressing the vibration transmitted to
the air conditioning case.
[0053] The fixing portion 30 is disposed at a position where a
frequency of the vibration mode of the evaporator 10 is different
from the natural frequency of a wall surface of the air
conditioning case. The natural frequency of the air conditioning
case is different depending on a location. If the fixing portion 30
is disposed at a position where the natural frequency of the air
conditioning case is the same as the frequency of the vibration
mode of the evaporator 10, even while the vibration transmitted
from the evaporator 10 is attenuated, the air conditioning case
largely vibrates. Therefore, the fixing portion 30 is disposed at a
position where the frequency of the vibration mode of the
evaporator 10 is different from the natural frequency of the wall
surface of the air conditioning case, thereby being capable of
restraining the effect of reducing the NV from being lowered due to
the natural frequency of the air conditioning case.
[0054] Further, in this embodiment, when the length of the first
side 31 is defined as L, the fixing portion 30 is disposed at a
position apart by 0.25 L.+-.0.05 L, and a position apart by 0.75
L.+-.0.05 L from the end of the first side 31. As illustrated in
FIG. 3, the position of 0.25 L and the position of 0.75 L are
positions of nodes. Since the fixing portion 30 is disposed in the
vicinity (.+-.0.05 L) of the positions of the nodes, the effect of
reducing the NV can be achieved as described above.
[0055] In other words, in this embodiment, for the purpose of
reducing the NV in the air conditioning apparatus for a vehicle,
attention is focused on the vibration mode of the evaporator 10,
and the fixing position of the evaporator 10 is optimized to
suppress the vibration propagation to the air conditioning
apparatus. Specifically, the evaporator 10 is fixed at the position
except for the vicinity of the antinode parts of the evaporator 10,
thereby being capable of reducing the NV in the air conditioning
apparatus. Because the transmission of a main vibration mode of the
evaporator 10 to the air conditioning case can be suppressed by
pressing the nodes of the evaporator 10, the NV can be reduced in
the air conditioning apparatus for a vehicle.
Second Embodiment
[0056] A second embodiment of the present disclosure will be
described with reference to FIGS. 7 and 8. FIG. 7 illustrates an
air conditioning apparatus for a vehicle, and an evaporator 10A is
illustrated as an element configuring the air conditioning
apparatus. The evaporator 10A configuring the air conditioning
apparatus illustrated in FIG. 7 is integrally provided with an
expansion valve 40. The evaporator 10A is connected to an outflow
side of the expansion valve 40 in a refrigeration cycle device, and
a refrigerant depressurized by the expansion valve 40 flows into
the evaporator 10A. In the present embodiment, the fixing portion
30 is disposed at six locations. The respective fixing portion 30
is configured by a protrusion portion, similarly to the first
embodiment.
[0057] As illustrated in FIG. 7, the fixing portions 30 are
disposed in each of an upper tank unit 12 and a lower tank unit 13
at positions apart by 0.25 L.+-.0.05 L and positions apart by 0.75
L.+-.0.05 L from an end of a first side 31. Since the positions of
the fixing portions 30 in the first side 31 are the same as those
in the first embodiment described above, the same operation and
effects can be achieved.
[0058] Moreover, the fixing portions 30 are disposed on respective
side plates 16 located on both ends in the longitudinal direction
X. Specifically, when it is assumed that a length of a second side
32 is W, the fixing portions 30 are preferably disposed at
positions apart from an end of the second side 32 by 0.5 W.+-.0.05
W. In the present specification, 0.5 W means 0.5.times.W. Regarding
the second side 32, as illustrated in FIG. 8, a position of 0.5 W
is a position forming a node in the second side 32. Since the
fixing portions 30 are disposed in the vicinity (.+-.0.05 W) of the
position of the node, the effect of reducing the NV can be achieved
as with the position of the fixing portions 30 of the first side
31. In this embodiment, since the evaporator 10 is fixed at six
locations in the outer periphery, the evaporator 10 can be more
firmly fixed to the air conditioning case.
Third Embodiment
[0059] A third embodiment of the present disclosure will be
described with reference to FIG. 9. In FIG. 9, a configuration of a
fixing portion 30B is different from that in the evaporator 10 of
the first embodiment. The fixing portion 30B of the evaporator 10B
according to this embodiment is defined by a protrusion portion
protruding outward from a lower tank unit 13 as described above.
Further, the protrusion portion is covered with an elastic member,
for example, an antivibration rubber.
[0060] The fixing portion 30B is configured integrally with the
protrusion portion and the elastic member, thereby being capable of
surely bringing the elastic member in contact with the air
conditioning case. With the above configuration, the vibration
transmitted from the fixing portion 30B to the air conditioning
case can be further attenuated.
Fourth Embodiment
[0061] A fourth embodiment of the present disclosure will be
described with reference to FIG. 10. In FIG. 10, the position of
the fixing portion 30 is different from that in the evaporator 10
of the first embodiment described above. The positions of the
fixing portions 30 according to this embodiment are disposed on
respective side plates 16 located on both ends in the longitudinal
direction X. Specifically, when it is assumed that a length of a
second side 32 is W, the fixing portions 30 are preferably disposed
at positions apart from an end of the second side 32 by 0.5
W.+-.0.05 W (positions indicated by imaginary lines 21 in FIG. 10).
Regarding the second side 32, as illustrated in FIG. 8, a position
of 0.5 W is a position forming a node in the second side 32. Since
the fixing portion 30 is disposed in the vicinity (.+-.0.05 W) of
the positions of the nodes, the effect of reducing the NV can be
achieved.
OTHER EMBODIMENTS
[0062] Hereinbefore, the preferred embodiments of the present
disclosure are described. However, the present disclosure is not
intended to be limited to the embodiments described above, and
various modifications can be made as long as they do not depart
from the gist thereof.
[0063] The structures of the embodiments described above are merely
examples and the scope of the present disclosure is not intended to
be limited to the scope described above. The scope of the present
disclosure is represented by the claims, and includes meanings
equivalent to those of the claims, and all changes in the
scope.
[0064] In the first embodiment described above, the fixing portions
30 are disposed at two locations, but is not limited to two
locations, and at least one fixing portion 30 may be disposed on at
least one of a surface surrounded by the first side 31 and the
third side 33 and a surface surrounded by the second side 32 and
the third side 33. Therefore, for example, the fixing portion 30
may be disposed on only the side plate 16.
[0065] In the first embodiment described above, the evaporator 10
configures the air conditioning apparatus for a vehicle, but is not
limited to the vehicle, and the evaporator may configure a domestic
air conditioning apparatus. The present disclosure is not limited
to be applied to the evaporator, but may be applied to a radiator
or a condenser if the heat exchanger has a rectangular
parallelepiped shape in which refrigerant flows.
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