U.S. patent application number 13/371599 was filed with the patent office on 2012-08-16 for aerodynamic sound decreasing apparatus.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Koji Ito, Masaru Kamiya, Shinya Kato.
Application Number | 20120205070 13/371599 |
Document ID | / |
Family ID | 46636006 |
Filed Date | 2012-08-16 |
United States Patent
Application |
20120205070 |
Kind Code |
A1 |
Kamiya; Masaru ; et
al. |
August 16, 2012 |
AERODYNAMIC SOUND DECREASING APPARATUS
Abstract
Multiple projections are provided at a flow-change portion,
which corresponds to such a portion of a wall surface of an A/C
casing, at which velocity gradient of air current becomes larger in
an area adjacent to the wall surface, in order to decrease
aerodynamic sound generated by disturbed air current.
Inventors: |
Kamiya; Masaru;
(Toyoake-city, JP) ; Ito; Koji; (Nagoya-city,
JP) ; Kato; Shinya; (Hekinan-city, JP) |
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
46636006 |
Appl. No.: |
13/371599 |
Filed: |
February 13, 2012 |
Current U.S.
Class: |
165/96 ;
165/104.34; 181/224 |
Current CPC
Class: |
F04D 29/681 20130101;
F24F 13/24 20130101; B60H 1/00564 20130101; B60H 1/00514 20130101;
F04D 29/663 20130101; B60H 2001/006 20130101 |
Class at
Publication: |
165/96 ; 181/224;
165/104.34 |
International
Class: |
E04F 17/04 20060101
E04F017/04; F28D 15/00 20060101 F28D015/00; F28F 27/00 20060101
F28F027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 16, 2011 |
JP |
2011-031171 |
Oct 31, 2011 |
JP |
2011-238444 |
Claims
1. An aerodynamic sound decreasing apparatus comprising: an air
passage formed by a passage forming member; an aerodynamic sound
decreasing member provided on a wall surface of the passage forming
member for decreasing velocity gradient of an air current colliding
against a portion of the wall surface, wherein the aerodynamic
sound decreasing member is provided at such a flow-change portion,
at which a shape of the wall surface is changed, and at which the
velocity gradient of the air current will be increased in an area
adjacent to the wall surface.
2. The aerodynamic sound decreasing apparatus according to the
claim 1, wherein the aerodynamic sound decreasing member is
composed of multiple lines of projections formed on the wall
surface and projecting from the wall surface.
3. The aerodynamic sound decreasing apparatus according to the
claim 1, wherein the aerodynamic sound decreasing member is
composed of a plate member arranged in the air passage and
separated from the wall surface, wherein the plate member has
multiple through-holes.
4. The aerodynamic sound decreasing apparatus according to the
claim 1, wherein the air current collides against the flow-change
portion and thereby a flow direction of the air current is
changed.
5. The aerodynamic sound decreasing apparatus according to the
claim 1, further comprising; a blocking plate provided on the wall
surface so as to project from the wall surface for blocking a part
of the air current flowing through the air passage, wherein the
aerodynamic sound decreasing member is provided at the flow-change
portion, which corresponds to a portion of the wall surface at a
downstream side of the blocking plate, so that the air current
disturbed by the blocking plate collides against the aerodynamic
sound decreasing member.
6. The aerodynamic sound decreasing apparatus according to the
claim 1, further comprising; a guide plate provided on the wall
surface so as to project from the wall surface for guiding a part
of the air current flowing through the air passage, wherein the
aerodynamic sound decreasing member is provided at the flow-change
portion, which corresponds to a portion of the wall surface at a
downstream side of the guide plate, so that the air current
disturbed by the guide plate collides against the aerodynamic sound
decreasing member.
7. The aerodynamic sound decreasing apparatus according to the
claim 1, wherein the aerodynamic sound decreasing apparatus is
applied to an air conditioning apparatus for a vehicle, the air
passage corresponds to a passage for supplying conditioned air into
a passenger compartment of the vehicle, the passage forming member
is composed of an A/C casing for forming the air passage in the
inside thereof, and the aerodynamic sound decreasing member is
provided at the flow-change portion, which corresponds to a door
surface of an air switching door for opening and closing the air
passage and/or on a plate surface of a partitioning wall of the A/C
casing surrounding and/or neighboring to the air switching door,
wherein the air current collides against the door surface and/or
the plate surface and thereby a direction the air current is
changed.
8. The aerodynamic sound decreasing apparatus according to the
claim 7, wherein the air switching door corresponds to a door for
opening and closing the air passage, which connects an inside space
of the A/C casing to the passenger compartment, and the aerodynamic
sound decreasing member is provided at the flow-change portion,
which corresponds to the door surface and/or the plate surface,
which faces to the inside space of the A/C casing when the air
switching door is in its closed condition.
9. The aerodynamic sound decreasing apparatus according to the
claim 7, wherein air conditioning apparatus includes an evaporator
and a heater core in the inside space of the A/C casing, wherein
the air current passes through the evaporator and/or the heater
core, the air switching door corresponds to an air-mix door for
controlling an air-mix ratio between cold air having passed through
the evaporator and hot air having passed through the heater
core.
10. The aerodynamic sound decreasing apparatus according to the
claim 8, further comprising; a sealing portion provided on the wall
surface so as to project from the wall surface for blocking a part
of the air current flowing through the air passage, wherein an
outer peripheral portion of the air switching door is in contact
with the sealing portion when the air switching door is closed,
wherein the aerodynamic sound decreasing member is provided at the
flow-change portion, which corresponds to a portion of the wall
surface, which is located at a downstream side of the sealing
portion and at which the air current disturbed by the sealing
portion collides against the aerodynamic sound decreasing member
when the air switching door is in its opened condition.
11. The aerodynamic sound decreasing apparatus according to the
claim 8, wherein the air current disturbed by the outer peripheral
portion of the air switching door collides against the aerodynamic
sound decreasing member when the air switching door is in its
opened condition.
12. The aerodynamic sound decreasing apparatus according to the
claim 8, further comprising; a sealing portion provided on the wall
surface so as to project from the wall surface for blocking apart
of the air current flowing through the air passage, wherein an
outer peripheral portion of the air switching door is in contact
with the sealing portion when the air switching door is closed; and
an elastic lip seal member provided at an outer periphery of the
air switching door and in contact with the sealing portion when the
air switching door is in its closed condition, wherein the
aerodynamic sound decreasing member is provided at the flow-change
portion, which corresponds to a portion of the door surface of the
air switching door, which is on a downstream side of the air
current.
13. The aerodynamic sound decreasing apparatus according to the
claim 8, wherein a rib is provided on the door surface of the air
switching door for reinforcing the same, wherein the rib projects
from the door surface, and the aerodynamic sound decreasing member
is provided at the flow-change portion, which corresponds to a
portion of the door surface of the air switching door, at which the
air current disturbed by the rib collides against the aerodynamic
sound decreasing member.
14. The aerodynamic sound decreasing apparatus according to the
claim 1, wherein the aerodynamic sound decreasing apparatus is
applied to an air conditioning apparatus for a vehicle, the air
passage corresponds to a passage for supplying conditioned air into
a passenger compartment of the vehicle, the passage forming member
is composed of an A/C casing for forming the air passage in the
inside thereof, a heat exchanger is provided in the air passage
through which the air current passes, and the aerodynamic sound
decreasing member is provided at the flow-change portion, which
corresponds to a part of a partitioning wall of the A/C casing,
which is located at a downstream side of the heat exchanger and
faces to the heat exchanger.
15. The aerodynamic sound decreasing apparatus according to the
claim 1, wherein the aerodynamic sound decreasing apparatus is
applied to an air conditioning apparatus for a vehicle, the air
passage corresponds to a passage for supplying conditioned air into
a passenger compartment of the vehicle, the passage forming member
is composed of an A/C casing for forming the air passage in the
inside thereof, a guide plate is provided in the air passage for
adjusting a ratio between cold air and hot air, the aerodynamic
sound decreasing member is provided at the flow-change portion,
which corresponds to a part of the plate surface of the guide
plate.
16. The aerodynamic sound decreasing apparatus according to the
claim 7, wherein the aerodynamic sound decreasing member is
provided on a part of the wall surface of the A/C casing, toward
which air from a blower unit is blown out into the inside space of
the A/C casing.
17. The aerodynamic sound decreasing apparatus according to the
claim 1, wherein the air passage formed by the passage forming
member includes an air passage through which air is supplied into
an inside space of an A/C casing, the passage forming member
includes a scroll casing for forming the air passage in an inside
of the scroll casing so as to supply air from a centrifugal type
blower unit into the inside space of the A/C casing, and the
aerodynamic sound decreasing member is provided at the flow-change
portion, which corresponds to a part of a wall surface of the
scroll casing, at which a flow direction of air is changed from an
sir drawing direction to a centrifugal direction.
18. The aerodynamic sound decreasing apparatus according to the
claim 1, wherein the air passage formed by the passage forming
member includes an air passage through which air is supplied into
an inside space of an A/C casing, the passage forming member
includes a scroll casing for forming the air passage in an inside
of the scroll casing so as to supply air from a blower unit into
the inside space of the A/C casing, and the aerodynamic sound
decreasing member is provided at the flow-change portion, which
corresponds to a part of a wall surface of the scroll casing at its
volute tongue.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2011-031171 filed on Feb. 16, 2011, and No. 2011-238444 filed on
Oct. 31, 2011, the disclosures of which are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an aerodynamic sound
decreasing apparatus for decreasing aerodynamic sound generated by
turbulence of air flow.
BACKGROUND OF THE INVENTION
[0003] It is known in the art, according to which a member or a
device for decreasing pressure variation (hereinafter also referred
to as a noise decreasing member) is provided on a product surface
in order to decrease aerodynamic sound (also referred to as noise)
generated in a blower device for blowing out conditioned air or
cold air, for example, as disclosed in the following patent
publications: [0004] (1) Japanese Patent Publication No.
H02-253000; [0005] (2) Japanese Patent Publication No. H05-026762;
[0006] (3) Japanese Patent Publication No. H07-225048; [0007] (4)
Japanese Patent Publication No. 2003-161295; and [0008] (5)
Japanese Patent Publication No. 2006-159924.
[0009] For example, a structure for providing a plumate or
wire-rod-shaped projections or furry and fibrous members is
described as the noise decreasing member, in the above patent
publications.
[0010] In a case that one of the noise decreasing members disclosed
in the above patent publications is applied to an air duct of an
air conditioning apparatus for a vehicle, wherein the air duct has
a bended portion, it is not possible to achieve a sufficient noise
decreasing effect. It is difficult to use such noise decreasing
member in view of an industrial application, because it may cause a
decrease of performance and/or an increase of manufacturing
cost.
[0011] When the technology disclosed in the above patent
publications (1) or (3) is applied to the air conditioning
apparatus for the vehicle, it may be necessary to provide a lot of
projections in a plume structure on an inner surface so as to break
a vortex flow into multiple smaller portions, or it may be
necessary to provide small fibrous members in a furry condition
(that is, a kind of hair-implant process) so as to softly receive
the vortex flow by cushioning action.
[0012] A part (a member) of the air conditioning apparatus for the
vehicle, which forms a wall of an A/C casing, is generally made of
resin by a molding process. Therefore, it may become necessary to
add the above kind of the hair-implant process in the resin-molding
process. It may cause an increase of the manufacturing cost.
[0013] In addition, when the fibrous members may come off due to a
secular change, not only the noise reducing effect may be decreased
but also the air duct of the air conditioning apparatus may be
blocked by such fibrous members or the fibrous members may be
blasted off from a duct opening into a passenger compartment to
thereby provide an uncomfortable feeling to a vehicle
passenger.
[0014] In addition, in a case that the technology of the above
patent publication (2) is applied to the air conditioning apparatus
for the vehicle, it is necessary that a boundary-layer flow partly
transits to a turbulent boundary layer in an area adjacent to air
blow-out ports and air duct openings. Therefore, it may be
necessary to provide a facilitating member on a surface which is in
contact with the air flow, so that the boundary-layer flow partly
transits to the turbulent boundary layer.
[0015] However, since the air conditioning apparatus for the
vehicle is composed of multiple complicated air passages, which
have a lot of bended portions in the inside thereof, the noises are
also generated at such portions other than the air blow-out ports
and the air duct openings. Therefore, even when the noise generated
in the area adjacent to the air blow-out ports and/or the air duct
openings can be decreased, the noise as a whole can not be still
sufficiently decreased. Since cold air and hot air is mixed with
each other in order to adjust temperature of the air in the air
conditioning apparatus for the vehicle, air currents in the inside
of the air conditioning apparatus are largely disturbed and those
air currents are in a condition of the turbulent flow. If the above
facilitating member was provided, the turbulence of the air
currents would be further increased and the noise would be
increased on the contrary.
[0016] In addition, in the case that the noise decreasing members
of the above patent publications (1) to (3) were provided in
various portions of the air passage for the purpose of decreasing
the noise, the noise decreasing members would become resistance for
the air flow to thereby cause another problem that a flow rate may
be decreased in accordance with an increase of the area, in which
the noise decreasing members are provided.
[0017] It might be possible to increase rotational speed of a
blower unit and to supply the air at a higher pressure so as to
compensate the decrease of the flow rate. However, the noise will
be correspondingly increased. Namely, the aerodynamic sound for the
unit flow rate may be increased.
[0018] In addition, in the case that the technology of the above
patent publication (4) was applied to the air conditioning
apparatus for the vehicle, it would be possible to decrease the
noise, which will be generated at portions, such as forward
portions of ribs, inside wall surfaces of the bended portions or
the like, at which the air currents are separated. However, on the
other hand, it would not be possible to decrease the noise which
will be generated when the air currents separated at the bended
portions or the forward ends of the ribs collide against wall
surfaces around them, or the noise which will be generated when the
air currents collide against an outer wall surface of the bended
portion. Therefore, it is not possible to decrease the noise as a
whole. The technology of the patent publication (5) is applied to a
reduced portion of the air passage. Therefore, it is not possible
to decrease the noise, which will be generated at other portions
than the above reduced portion. In other words, even according to
the technology of the patent publication (5), it is not possible to
decrease the noise as a whole, either.
SUMMARY OF THE INVENTION
[0019] The present invention is made in view of the above problems.
It is an object of the present invention to provide an aerodynamic
sound decreasing apparatus, according to which the aerodynamic
sound can be decreased while a decrease of the flow rate can be
avoided.
[0020] According to a feature of the present invention (for
example, as defined in the appended claim 1), in aerodynamic sound
decreasing apparatus, an air passage is formed by a passage forming
member. An aerodynamic sound decreasing member is provided on a
wall surface of the passage forming member for decreasing velocity
gradient of an air current colliding against a portion of the wall
surface. The aerodynamic sound decreasing member is provided at
such a speed-change portion, at which a shape of the wall surface
is changed, and at which the velocity gradient of the air current
will be increased in an area adjacent to the wall surface.
[0021] According to the above feature, the aerodynamic sound
decreasing member for decreasing the velocity gradient is provided
at such a portion, at which the velocity gradient will become
larger. In other words, the aerodynamic sound decreasing member is
provided at such a portion of the wall surface, a shape of which is
changed and against which the air current collides. Accordingly,
the velocity gradient becomes smaller in the area adjacent to the
wall surface, while the velocity gradient is maximized in an area
away from the wall surface. As above, vorticity which would cause
the noise will be decreased and a maximum vorticity is away from
the wall surface, to thereby decrease the noise.
[0022] The aerodynamic sound decreasing member is provided not on
the whole area of the wall surface of the air passage but on a part
thereof. Therefore, manufacturing cost can be reduced. Therefore,
it is possible to decrease the noise, while suppressing decrease of
flow rate and increase of the manufacturing cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The above and other objects, features and advantages of the
present invention will become more apparent from the following
detailed description made with reference to the accompanying
drawings. In the drawings:
[0024] FIG. 1 is a schematic view showing an outline of a structure
of an air conditioning apparatus 10 and a blower unit 60, according
to a first embodiment of the present invention;
[0025] FIG. 2 is a schematic cross sectional view showing the
blower unit 60;
[0026] FIG. 3 is a schematic cross sectional view showing the air
conditioning apparatus 10 for explaining an operation (a maximum
cooling operation);
[0027] FIG. 4 is also a schematic cross sectional view showing the
air conditioning apparatus 10 for explaining the operation (a
maximum heating operation);
[0028] FIG. 5 is a schematic view showing a bended portion "Z" and
air currents at the bended portion;
[0029] FIG. 6 is a schematic view showing air currents in an air
passage which is enlarged in a downward direction;
[0030] FIG. 7 is a schematic view showing a velocity gradient at
the bended portion "Z";
[0031] FIG. 8 is a schematic view showing an example of flow
velocity;
[0032] FIG. 9 is a schematic view showing an example of vorticity
corresponding to the air currents in FIG. 8;
[0033] FIG. 10 is a schematic view showing another example of flow
velocity;
[0034] FIG. 11 is a schematic view showing another example of
vorticity corresponding to the air currents in FIG. 10;
[0035] FIG. 12 is a schematic perspective view showing projections
40;
[0036] FIG. 13 is a schematic view showing an example of
relationship between the multiple projections 40 and the flow
velocity;
[0037] FIG. 14 is a schematic perspective view showing an example
(the first embodiment) of the multiple projections 40;
[0038] FIG. 15 is a graph showing an example of relationship
between a diameter of the projection 40 and noise;
[0039] FIG. 16 is a graph showing an example of relationship
between a height of the projection 40 and noise;
[0040] FIG. 17 is a graph showing an example of relationship
between a distance of the neighboring projection 40 and noise;
[0041] FIG. 18 is a schematic cross sectional view showing an air
passage 13A according to a second embodiment;
[0042] FIG. 19 is a schematic cross sectional view showing an air
passage 13B according to a third embodiment;
[0043] FIG. 20 is a schematic cross sectional view showing an air
passage 13C according to a fourth embodiment;
[0044] FIG. 21 is a schematic cross sectional view showing an air
passage 13D according to a fifth embodiment;
[0045] FIG. 22 is a schematic cross sectional view showing an air
passage 13E according to a sixth embodiment; and
[0046] FIGS. 23 to 37 are schematic perspective views, respectively
showing a first to a fifteenth modification of the projection.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0047] The present invention will be explained by way of multiple
embodiments with reference to the drawings. The same reference
numerals are used throughout the multiple embodiments for the
purpose of designating the same or similar parts and/or portions,
so that repeated explanation will be eliminated.
First Embodiment
[0048] A first embodiment of the present invention will be
explained with reference to FIGS. 1 to 17. FIG. 1 schematically
shows an outlined structure of an air conditioning apparatus 10 and
a blower unit 60 for a vehicle. FIG. 2 is a cross sectional view
showing the blower unit 60. FIG. 3 is a schematic view showing the
outlined structure of the air conditioning apparatus 10 for the
vehicle. The air conditioning apparatus 10 controls temperature of
the air in a passenger compartment of the vehicle.
[0049] The air conditioning apparatus 10 (hereinafter, simply
referred to as an A/C apparatus) has an air conditioner casing 11
(an A/C casing 11) being composed of an air blowing portion and an
air controlling portion. The A/C casing 11 is arranged at a back
side of an instrument panel 12 in the passenger compartment of the
vehicle. The A/C casing 11 functions as a passage member for
forming air passages in an inside thereof. The A/C casing 11 is
composed of multiple casing members, which are made of resin (such
as, polypropylene) by a resin-molding process. The multiple casing
members are integrally fixed to each other by fixing members (such
as, metal springs, metal screws and so on), so as to form the A/C
casing 11.
[0050] The A/C apparatus 10 respectively supplies air-conditioned
air into the passenger compartment from duct openings on a
left-hand side and a right-hand side of the vehicle. More exactly,
the A/C apparatus 10 controls temperature of the air on a driver
side and temperature of the air on a passenger side independently
from each other, so that a right-and-left independent control for
the temperature is realized. A partitioning wall 14 is provided in
the inside of the A/C casing 11, in order that the air on the
right-hand side and the air on the left-hand side will not be mixed
up with each other. Therefore, the inside of the A/C casing 11 is
divided into two air passage portions by the partitioning wall
14.
[0051] The air blowing portion includes the blower unit 60 for
blowing inside air or outside air toward the air controlling
portion. An outlet port of the blower unit 60 is connected to an
inlet port of an air passage 13 of the air controlling portion. The
blower unit 60 is composed of a centrifugal forward curved fan 61
and a motor 64 for driving the centrifugal fan 61. A periphery of
the centrifugal fan 61 is surrounded by a scroll casing 62, which
is connected to the air passage 13 through a duct extending in a
centrifugal direction of the centrifugal fan 61.
[0052] The scroll casing 62 accommodates the centrifugal fan 61 and
is a convoluted member for forming a passage for the air, which
will be blasted off from the centrifugal fan 61. A nose portion 62a
is formed at a wall surface 62b of the scroll casing 62. The nose
portion 62a corresponds to a volute tongue of the scroll casing
62.
[0053] In the inside of the A/C casing 11, the air controlling
portion includes an evaporator 20 covering a whole passage area of
the air passage 13 in its cross section, a heater core 21 for
heating the air having passed through the evaporator 20, a cold air
passage 22, a main air-mix door 23, a sub air-mix door 24 for a
defroster, a hot air passage 25, an air-mix chamber 26 in which
cold air and hot air are mixed with each other, a defroster door
27, a face door 28, a foot door 29, and a rear door 30. In
addition, multiple air blow-out ports 31 to 34 are formed in the
A/C casing 11 at a downstream side of the cold air passage 22 and
the hot air passage 25. For example, a defroster blow-out port 31,
a face blow-out port 32, a first rear blow-out port 34 and a second
rear blow-out port 35 are respectively formed at the A/C casing 11.
The above doors 23, 24, 27, 28, 29 and 30 are collectively referred
to as air switching doors.
[0054] The defroster blow-out port 31 is provided at an upper
portion of the A/C casing 11 on a vehicle front side. A defroster
duct opening 31a, which is one of duct openings opening to the
inside of the passenger compartment of the vehicle, is formed at
the instrument panel 12 close to a front windshield glass 12a and
on the vehicle front side. The defroster blow-out port 31 and the
defroster duct opening 31a are connected to each other via a
defroster duct 31b so as to blow out the air toward the windshield
glass 12a to remove frost from the windshield glass. An opening
and/or closing of the defroster blow-out port 31 is controlled by
the defroster door 27.
[0055] The face blow-out port 32 is provided at the upper portion
of the A/C casing 11 on a vehicle rear side. A face duct opening
32a, which is another one of the duct openings opening to the
inside of the passenger compartment of the vehicle, is formed at
the instrument panel 12 facing to the vehicle driver or a front
passenger on the vehicle rear side of the panel. The face blow-out
port 32 and the face duct opening 32a are connected to each other
via a face duct 32b so as to blow out the air toward an upper body
of the vehicle driver or the front passenger. An opening and/or
closing of the face blow-out port 32 is controlled by the face door
28.
[0056] Each of the first and second rear blow-out ports 34 and 35
is provided at a lower portion of the A/C casing 11 on the vehicle
rear side. A rear duct opening (not shown), which is a further one
of the duct openings opening to the inside of the passenger
compartment of the vehicle, is formed at a portion close to a rear
seat. Each of the rear blow-out ports 34 and 35 and each of the
rear duct openings are connected to each other via each of rear
ducts 34b so as to blowout the air toward the rear seat. An opening
area of each rear blow-out port 34, 35 is controlled by the rear
door 30. When the first rear blow-out port 34 is opened by the rear
door 30, the hot air heated by the heater core 21 flows through the
rear duct 34b. When the second rear blow-out port 35 is opened by
the rear door 30, the cold air cooled down by the evaporator 20
flows through the rear duct 34b.
[0057] The foot blow-out port 33 is provided at the upper portion
of the A/C casing 11 but at a position lower than the face blow-out
port 32. A foot duct opening (not shown), which is a further one of
the duct openings opening to the inside of the passenger
compartment of the vehicle, is formed at a portion close to the
passenger's feet. The foot blow-out port 33 and the foot duct
opening are connected to each other via a foot duct (not shown) so
as to blow out the air toward the feet of the vehicle driver and/or
the front passenger. An opening area of the foot blow-out port 33
is controlled by the foot door 29.
[0058] The respective air blow-out ports 31 to 35 formed in the A/C
casing 11 on the left-hand and right-hand sides of the vehicle are
symmetric with each other, so that each of the air blow-out ports
31 to 35 respectively supplies the conditioned air to the vehicle
driver side and the front passenger side. The conditioned air from
each of the air blow-out ports 31 to 35 passes through the
respective air ducts 31b, 32b and 34b and blown out from the
respective duct openings 31a, 32a, and so on.
[0059] Each of the defroster door 27, the face door 28 and the foot
door 29 is a plate-type door, which is composed of a rotational
shaft and a flat door plate one side of which is rotatably
supported by the rotational shaft. The rear door 30 is also a
plate-type door having a rotational shaft and a flat door plate,
wherein one side of the door plate is likewise rotatably supported
by the rotational shaft. Each of operations of the blower unit 60,
the air-mix door 23, the sub air-mix door 24 for the defroster, the
defroster door 27, the face door 28, the foot door 29 and the rear
door 30 is controlled by an electronic control unit (not
shown).
[0060] The evaporator 20 is arranged in the A/C casing 11 on the
vehicle front side. The evaporator 20 is a heat exchanger for
cooling down the air passing therethrough by vaporizing
low-pressure and low-temperature refrigerant, which is
depressurized by an expansion valve of a refrigerating cycle, when
the air from the blower unit 60 passes through the evaporator 20.
The air passing through multiple tubes of the evaporator 20,
through which the refrigerant flows, is cooled down and supplied
into the cold air passage 22 located at a downstream side of the
evaporator 20.
[0061] The heater core 21 is arranged in the A/C casing 11 on the
vehicle rear side of the evaporator 20. The heater core 21 is a
heat exchanger for heating the air passing therethrough by
exchanging heat between engine cooling water (hot water) and the
air. The heater core 21 is located at a downstream side of the
evaporator 20 for covering a part of the air passage in the A/C
casing 11.
[0062] The sub air-mix door 24 for the defroster is also arranged
in the A/C casing 11 on the vehicle rear side of the evaporator 20.
The air-mix door 23 opens and/or closes a part of the cold air
passage 22, through which the cold air from the evaporator 20
passes. The air-mix door 23 is also arranged in the A/C casing 11
on the vehicle rear side of the evaporator 20. The air-mix door 23
opens and/or closes a main part of the cold air passage 22 and the
hot air passage 25, through which the cold air from the evaporator
20 passes.
[0063] The air-mix door 23 as well as the sub air-mix door 24 for
the defroster controls a flow amount of the hot air passing through
the heater core 21 and a flow amount of the cold air not passing
through the heater core 21 depending on opening degrees of those
doors 23 and 24, so that the temperature of the air is controlled.
When the air-mix door 23 and the sub air-mix door 24 are located at
positions indicated by solid lines in FIG. 3, the A/C apparatus 10
is in its maximum cooling operation, wherein the hot air passage 25
is closed in order to completely block the air flow toward the
heater core 21 and thereby provide the cold air into the passenger
compartment. In the condition shown in FIG. 3, a face mode is
selected. The air-mix door 23, the sub air-mix door 24, the
defroster door 27, the face door 28, the foot door 29 and the rear
door 30 are moved to positions (indicated by the respective solid
lines) shown in FIG. 3 so as to carry out the face mode
operation.
[0064] FIG. 4 is a cross sectional view also showing the structure
of the A/C apparatus 10 for the vehicle, wherein the positions of
the respective doors are different from those of FIG. 3. When the
air-mix door 23 and the sub air-mix door 24 are located at the
positions indicated by solid lines in FIG. 4, the A/C apparatus 10
is in its maximum heating operation, wherein the air passage to the
air-mix chamber 26 is closed so that all of the air having passed
through the evaporator 20 flows to the heater core 21. The air is
heated and such hot air is supplied into the passenger
compartment.
[0065] When the air-mix door 23 and the sub air-mix door 24 are
located at such positions, which respectively correspond to
intermediate positions between the positions of FIG. 3 and FIG. 4,
each of the cold air passage 22 and the hot air passage 25 is
partly opened so that both of the cold air and hot air flow in a
downstream direction. Those cold air and hot air are mixed up in
the air-mix chamber 26, which is formed at an upstream side of the
respective air blow-out ports, so that the temperature of such
mixed air is controlled and such conditioned air is supplied into
the respective air ducts from the respective air blow-out ports to
the air duct openings.
[0066] The hot air passage 25 is inclined toward the vehicle rear
side and extends from the lower portion of the A/C casing 11 to the
upper portion thereof, that is, to the air-mix chamber 26. The hot
air passage 25 has a width covering an almost all space in the A/C
casing 11 in a horizontal direction of the vehicle. Such a width
dimension is larger than a dimension of the hot air passage 25 in a
longitudinal direction of the vehicle. In other words, the hot air
passage 25 is formed in a flat rectangular space having a smaller
thickness in the longitudinal direction but a larger width in the
horizontal direction of the vehicle and extending in a vertical
direction.
[0067] The face blow-out port 32 and the defroster blow-out port 31
are opening to the air-mix chamber 26. The first rear blow-out port
34 is opened to the hot air passage 25. The second rear blow-out
port 35 is opened to the air passage extending from the evaporator
20 to a space beneath the heater core 21, through which the cold
air not passing through the heater core 21 flows. Therefore, when
the rear door 30 is located at the position shown in FIG. 3
(indicated by the solid line), the first rear blow-out port 34 is
closed so that the cold air is blown out from the second rear
blow-out port 35 into the rear duct. On the other hand, when the
rear door 30 is located at the position shown in FIG. 4 (indicated
by the solid line), the second rear blow-out port 35 is closed so
that the hot air is blown out from the first rear blow-out port 34
into the rear duct.
[0068] According to the A/C apparatus 10 of the present invention,
aerodynamic sound decreasing members are formed so as to decrease
aerodynamic sound generated in the A/C apparatus. At first,
mechanism, according to which the aerodynamic sound will be
generated, will be explained. FIG. 5 schematically shows air flow
at a bended portion "Z" of the air passage. As shown in FIG. 5, at
the bended portion "Z", at which the air flow collides against a
wall surface 11a, an air current disturbed in an upper stream
and/or another air current having broken away from an inner bended
portion (opposite to the outer bended portion "Z") and largely
disturbed will interfere with (collide against) the wall surface
11a of the outer bended portion "Z", to thereby generate the
aerodynamic sound (which is called as vortex sound).
[0069] More in detail, when the disturbed air current interferes
with (collides against) the wall surface 11a, the air current
receives frictional resistance of the wall surface 11a by such
interference. The air current has velocity gradient, according to
which flow speed of the air current closer to the wall surface 11a
becomes lower, while the flow speed becomes higher as the air
current is remote far away from the wall surface 11a, to thereby
form a boundary layer.
[0070] FIG. 6 schematically shows air currents in the air passage
which is gradually enlarged toward a downstream direction. As shown
in FIG. 6, in the boundary layer at such a portion, the air passage
of which is enlarged, flow energy hardly flows into the air
currents adjacent to the wall surface 11a and thereby a back flow
A1 is generated at the wall surface 11a of the downstream side.
Therefore, the air current breaks away from the wall surface 11a.
Then, a swirl A2 is generated, which would cause the aerodynamic
sound A3.
[0071] FIG. 7 schematically shows velocity gradient of the air
currents at the bended portion "Z". As indicated by a hatched area
in FIG. 7, in the boundary layer of the bended portion "Z", at
which the air currents collide against the wall surface 11a, the
flow energy continuously flows into the boundary layer. Therefore,
the air currents do not break away from the wall surface 11a.
However, the velocity gradient at the area adjacent to the wall
surface 11a (a flow-change with respect to a distance from the wall
surface 11a) becomes larger.
[0072] FIG. 8 shows an example of flow velocity. FIG. 9 shows an
example of vorticity corresponding to FIG. 8. FIG. 10 shows another
example of the flow velocity. FIG. 11 shows another example of the
vorticity corresponding to FIG. 10. As shown in FIG. 8, when the
velocity gradient is larger in the area adjacent to the wall
surface 11a, the vorticity becomes correspondingly larger in the
area adjacent to the wall surface 11a, as shown in FIG. 9. As a
result, the sound at the boundary layer becomes larger.
[0073] On the other hand, as shown in FIG. 10, when the velocity
gradient is maximized in an area away from the wall surface 11a and
therefore the velocity gradient is smaller in the area adjacent to
the wall surface 11a, the vorticity is maximized in the area away
from the wall surface 11a and the vorticity becomes smaller in the
area adjacent to the wall surface 11a, as shown in FIG. 11. As a
result, the sound at the boundary layer becomes smaller. In other
words, the vorticity of the air current which would cause the
aerodynamic sound is approximately equivalent to a space derivative
value of the flow velocity, that is, a change of the flow velocity
with respect to the distance from the wall surface 11a.
Accordingly, a larger aerodynamic sound may be generated at the
portion, at which the air currents (the velocity gradient of which
becomes larger in the area adjacent to the wall surface 11a)
interfere with (collide against) the wall surface 11a.
[0074] In view of the above mechanism of generating the aerodynamic
sound, it is necessary to reduce the vorticity or the area of the
vorticity should be separated from the wall surface 11a, in order
to decrease the aerodynamic sound. In other words, it is necessary
to make the velocity gradient smaller in the area adjacent to the
wall surface 11a and the area of the high velocity gradient should
be separated from the wall surface 11a, in order to decrease the
aerodynamic sound at the portion at which the air currents
interfere with (collide against) the wall surface 11a.
[0075] The aerodynamic sound decreasing members of the present
embodiment are composed of multiple projections 40. The multiple
projections 40 are formed on the wall surface 11a of the A/C casing
11 so as to make smaller the velocity gradient of the air colliding
against the wall surface 11a. The multiple projections 40 are
formed in a predetermined surface portion(s) of at least one of the
wall surface 62b of the scroll casing 62 and the inner wall surface
11a of the A/C casing 11. The projections 40 are formed in multiple
lines, wherein each of them projects from the surface portion.
[0076] FIG. 12 is a perspective view schematically showing the
multiple projections 40. FIG. 13 is an example showing a
relationship between the multiple projections 40 and the flow
velocity. As shown in FIG. 12, when the air passes among the
multiple projections 40, there are generated a frictional
resistance R1 by the projections 40, a frictional resistance R2 by
the wall surface 11a and a pressure loss R3 by the projections 40.
As a result, as shown in FIG. 13, the velocity gradient can be made
smaller in the area adjacent to the wall surface 11a and the
maximum velocity gradient can be shifted toward the area away from
the wall surface 11a. As above, the noise can be reduced by the
multiple projections 40.
[0077] The multiple projections 40 will be further explained more
in detail. FIG. 14 is a schematic view showing an example of the
multiple projections 40. When the projections 40 are formed on the
wall surface 62b of the scroll casing and/or the wall surface 11a
of the A/C casing 11, the multiple projections can be integrally
formed with the wall surfaces 62b and/or 11a. When the projections
40 are integrally formed with the wall surfaces 62b and/or 11a, the
scroll casing 62 and/or the A/C casing 11 as well as the
projections 40 are made of the same material. For example, those
members (62b, 11a, 40) are integrally formed by an injection
molding process. In a similar manner, when the projections 40 are
formed on the doors, they can be integrally formed with each
other.
[0078] The predetermined surface portions (also referred to as a
projection-formed portion or a flow-change portion) of the wall
surfaces, on which the projections 40 are formed, will be
explained. The multiple projections 40 are formed at such portions,
at which the air flow direction is changed. In other words, the
multiple projections 40 are formed at such portions, at which a
shape of the wall surface 11a is changed and at which the velocity
gradient of the air flow becomes larger in the area adjacent to the
wall surface as a result that the air flow collides against the
wall surface 11a. More exactly, the predetermined surface portion
corresponds to the portion of the wall surface, at which the shape
of the wall surface 11a is changed and against which the air
currents collide so as to change the air flow direction. When the
wall surface 11a is not straight along the air flow but the air
passage is bended or curved, or when the air passage is expanded or
reduced, the wall surface 11a is included in the meaning of "the
shape of the wall surface 11a is changed". When the wall surface
11a includes a portion having an angle of attack, with which a flow
rate is not decreased by passage resistance, such a portion is also
included in the meaning of "the shape of the wall surface 11a is
changed". For example, the angle of attack is larger than 30
degrees with respect to a flow direction the air flow. The angle of
attack is preferably larger than 45 degrees and most preferably
larger than 60 degrees.
[0079] The multiple projections 40 are schematically indicated in
FIG. 1, while the projections 40 are indicated by hatched portions
in FIGS. 2 to 4. As shown in FIGS. 1 to 4, the projections 40 are
formed on the wall surface 62b of the scroll casing 62, the wall
surface 11a of the A/C casing 11, and on one or both sides of the
respective doors 23, 28 and 30.
[0080] One of the projection-formed portions (the flow-change
portions) for the wall surface 62b of the scroll casing 62, on
which the projections 40 are formed, corresponds to the nose
portion 62a, as shown in FIG. 1. The air currents are unstable at
the nose portion 62a and therefore the directions of the air
currents as well as the flow velocity are momentarily changed. The
other of the projection-formed portions corresponds to such a
portion 63, as shown in FIG. 2, at which the direction of the air
flow is changed from an air drawing direction to a centrifugal
direction. The other projection-formed portion 63 is a part of the
wall surface 62b of the scroll casing 62 on a side (a lower side in
FIG. 2) opposite to an air drawing side (an upper side in FIG. 2).
In an operation of the blower unit 60, the air is drawn into the
centrifugal fan 61 from the air drawing side, pressure of the air
is increased in respective spaces between fan blades of the
centrifugal fan 61, and pressurized air is pushed out from the fan
61 in the centrifugal direction. Then, the air flows along the
scroll casing 62 toward the outlet port. The air inside of the fan
61 collides against a front side periphery of the fan blades and
then pushed out from the fan blades in the centrifugal direction,
so that such pushed out air collides against the other
projection-formed portion 63.
[0081] A first projection-formed portion 41 (i.e. a flow-change
portion) on the wall surface 11a of the A/C casing 11 corresponds
to a part of the casing (a partitioning wall), which is located at
the downstream side of the evaporator 20 and opposes to the
evaporator 20 (FIGS. 3 and 4). A second projection-formed portion
42 (i.e. a flow-change portion) on the wall surface 11a of the A/C
casing 11 corresponds to a part of the casing (a partitioning
wall), which is located at the downstream side of the heater core
21 and opposes to the heater core 21 (FIGS. 3 and 4). A third
projection-formed portion 43 (i.e. a flow-change portion) on the
wall surface 11a of the A/C casing 11 corresponds to a part of the
casing (a partitioning portion), into which the air from the blower
unit 60 is supplied (FIG. 1). Namely, the third projection-formed
portion 43 is a part of the casing, which is located at the
upstream side of the evaporator 20 and forms the air passage
connected to the scroll casing 62 and at which the air flow
direction is changed so that the air flows toward the evaporator
20.
[0082] In addition, the projections 40 are formed on respective
door surfaces of the face door 28 and the rear door 30 on an inner
side thereof, which faces to the inside of the A/C casing 11 (the
hot air passage 25) when each of the doors is closed. More exactly,
the projections 40 are formed on the door surface of the rear door
30, which faces to the heater core 21 when the rear door 30 closes
the first rear blow-out port 34. The multiple projections 40 are
further formed on both door surfaces of the air-mix door 23.
[0083] A guide plate 51 is provided in the air-mix chamber 26. The
guide plate 51 is shown in FIG. 3, but not shown in FIG. 4 for the
purpose of simplification of the drawing. The guide plate 51 is
projected from the wall surface 11a for blocking a part of the air
flow so as to guide the same. More exactly, in a foot mode
operation, during which the air is blown out through the foot
blow-out port 33, the temperature of the air as well as the
distributed amount of the air is controlled by the guide plate 51.
As shown in FIG. 3, in a face mode operation, since the guide plate
51 becomes an obstacle to the air flow, the multiple projections 40
are formed on a plate surface of the guide plate 51 at such a
portion, which is on a downstream side and at which the air
disturbed by the guide plate 51 collides against. In addition,
since the guide plate 51 (in particular, a front side surface) also
forms a part of the wall surface 11a of the A/C casing 11, and
thereby the air flow collides against the front side surface of the
guide plate 51, the multiple projections 40 may be formed on the
front side surface. The guide plate 51 controls mixture of the cold
air and the hot air (a mixing ratio between them). The guide plate
51 further has a guide portion for avoiding mixture of the cold air
and the hot air (the mixing ratio is controlled at zero).
[0084] Another guide plate may be provided at a portion around the
face door 28 and/or the rear door 30 for guiding the air to the
respective doors. In such a case, the multiple projections 40 may
be formed on a plate surface, against which the air collides and
along which the air is guided to the doors.
[0085] As above, the multiple projections 40 are formed in several
portions on the wall surface 11a of the A/C casing 11. For example,
in the cooling operation shown in FIG. 3, as indicated by dotted
lines, a part of the air currents having passed through the
evaporator 20 collides against the air-mix door 23 and the
direction of those air currents is changed to the direction toward
the face blow-out port 32. On the other hand, the other part of the
air currents having passed through the evaporator 20 collides
against the first projection-formed portion 41 and thereby the
direction of those air currents is changed to the direction toward
the rear duct 34b (FIG. 1). In this operation, since the
projections 40 formed on the rear side surfaces of the face door 28
and the air-mix door 23 are not in contact with the air currents,
those projections 40 do not cause decrease of the air flow
rate.
[0086] In the heating operation shown in FIG. 4, as indicated by
dotted lines, a part of the air currents having passed through the
evaporator 20 collides against the rear side surface of the air-mix
door 23 and thereby the direction of those air currents is changed
to the direction toward the heater core 21. A part of the air
currents having passed through the heater core 21 collides against
the second projection-formed portion 42 and thereby the direction
of those air currents is changed to the direction toward the foot
door 29. The remaining part of the air currents having passed
through the heater core 21 collides against the inside surface of
the rear door 30 and thereby the direction of those air currents is
changed to the direction toward the rear duct opening (not shown).
In this operation, since the projections 40 formed on the front
side surface of the air-mix door 23 and the first projection-formed
portion 41 are not in contact with the air currents, those
projections 40 do not cause decrease of the air flow rate.
[0087] Dimensions and distribution for the projections 40 will be
explained with reference to FIGS. 15 to 17. FIG. 15 is a graph
showing an example of a relationship between a diameter of the
projection 40 and the noise. FIG. 16 is a graph showing an example
of a relationship between a height of the projection 40 and the
noise. FIG. 17 is a graph showing an example of a relationship
between a distance between the projections 40 and the noise. It is
necessary to properly set the diameter, the height and the distance
of the projections 40 so as to obtain appropriate frictional
resistance and the pressure loss, for the purpose of decreasing the
velocity gradient in the area adjacent to the wall surface 11a.
When the diameter is too small, the frictional resistance can not
be sufficiently obtained. Then, the flow velocity in the area
adjacent to the wall surface 11a can not be sufficiently decreased.
When the height of the projections is too small, the area in which
the velocity gradient is maximized can not be sufficiently
separated from the wall surface 11a. When the distance between the
projections is too large, the sufficient pressure loss can not be
obtained. Then, the flow velocity in the area adjacent to the wall
surface 11a can not be sufficiently decreased, either. In the
example shown in FIGS. 15 to 17, the projections of a cylindrical
shape as shown in FIG. 14 are formed on the wall surface 11a,
wherein the noise is measured when the air flow velocity is 5 m/s
and the angle of attack is 90 degrees.
[0088] At first, the diameter will be explained. According to the
example of FIG. 15, the height of the projection 40 is set to be 3
mm, the distance between the projections 40 is set to be 0.7 mm,
and the diameter of the projection 40 is varied. As shown in FIG.
15, the noise level becomes lower when the projections 40 are
formed. It is preferable when the diameter of the projection 40 is
larger than 0.1 mm, and more preferable when it is larger than 0.2
mm.
[0089] Next, the height will be explained. According to the example
of FIG. 16, the diameter of the projection 40 is set to be 0.5 mm,
the distance between the projections 40 is set to be 0.7 mm, and
the height of the projection 40 is varied. As shown in FIG. 16, the
noise level becomes lower when the projections 40 are formed. It is
preferable when the height of the projection 40 is larger than 1
mm, and more preferable when it is larger than 2 mm.
[0090] Now, the distance between the projections 40 will be
explained. According to the example of FIG. 17, the diameter of the
projection 40 is set to be 0.5 mm, the height of the projection 40
is set to be 3 mm, and the distance between the projections 40 is
varied. In FIG. 17, when the distance between the projections 40 is
infinite, it is regarded as a situation that the projections are
not formed. As shown in FIG. 17, the noise level becomes lower when
the projections 40 are formed. It is preferable when the distance
between the projections 40 is smaller than 1 mm, and more
preferable when it is less than 0.5 mm.
[0091] As explained above, according to the present embodiment, the
multiple projections 40 are formed on the projection-formed
portions (the flow-change portions) of the wall surface 11a, such
as the first projection-formed portion 41, at which the air flow
direction is changed. According to the researches of the present
inventors, the decrease of the flow rate is relatively large on the
wall surface 11a having small angle of attack, for example, in the
case of the air currents along the wall surface. On the other hand,
the flow rate will not be substantially decreased in such a
portion, where the angle of attack is large when the air flow
direction is changed and thereby the air currents collide against
each other. In addition, the aerodynamic sound is generated when
the swirls produced by the disturbance of the air currents are
transformed. The multiple projections 40 decrease the generation of
the aerodynamic sound by suppressing the deformation of the swirls.
Accordingly, the effect for decreasing the noise is not large, when
the projections are formed on such portions of the wall surface
11a, at which the disturbance of the air currents may not largely
take place (namely, the air currents smoothly flow on the wall
surface 11a).
[0092] According to the present embodiment, the multiple
projections 40 are formed on such portions of the wall surfaces 11a
(i.e. the flow-change portions), at which the velocity gradient of
the air flow becomes larger in the area adjacent to the wall
surface 11a. As a result, the aerodynamic sound, which is generated
by the disturbance of the air currents, can be decreased as shown
in FIGS. 15 to 17. In addition, since the air passage area of those
portions (the flow-change portions) at which the air currents
collide against the projection-formed surfaces is not reduced, and
since the frictional resistance of the projection-formed surface
will not be extremely increased, not only the noise generated by
the collision of the air currents can be decreased, but also the
aerodynamic sound generated by the disturbance of the air currents
can be effectively decreased without causing the decrease of the
flow rate. In addition, since the multiple projections 40 are
formed not on the whole area of the wall surface 11a but on the
part thereof, an increase of the manufacturing cost can be
suppressed. As above, according to the present embodiment, the
aerodynamic sound can be decreased, while the decrease of the flow
rate as well as the increase of the manufacturing cost is
avoided.
[0093] According to the present embodiment, when compared with the
conventional acoustic absorbing material and/or sound absorber, the
aerodynamic sound decreasing members can be formed in a simpler and
smaller-sized (thinner) structure by the multiple projections. It
is further possible to decrease the noise in a wide range of
frequency. In the case of the air conditioning apparatus for the
vehicle, a small-sized structure is always required for easily
mounting the A/C apparatus in the vehicle, and the noise is
generated in the wide range of the frequency. Therefore, the
present invention can be preferably applied to the A/C apparatus
for the vehicle.
[0094] According to the present embodiment, the face door 28, the
rear door 30, and so on are provided in the A/C casing 11 for
opening and closing the air passages. In case of those doors 28 and
30, the air currents collide against one of the surfaces (the front
or rear side surface) of each of those doors and the direction of
the air flow is changed. Therefore, when the multiple projections
40 are formed on the surfaces of the doors 28 and 30, it is
possible to suppress the generation of the swirl deformation and
thereby to decrease the aerodynamic sound.
[0095] According to the present embodiment, the multiple
projections 40 are formed on the doors (such as, the face door 28,
the rear door 30) for opening and/or closing the air ducts
connecting the inside of the A/C casing 11 with the passenger
compartment. When those doors are in the closed condition, the air
currents collide against the door surfaces on the side facing to
the inside of the A/C casing 11 and thereby the air flow direction
is changed. Since the multiple projections 40 are formed on such
door surfaces, it is possible to suppress the deformation of the
generated swirls to thereby decrease the aerodynamic sound. On the
other hand, when the doors are in the opened condition, the air
currents flow along the door surfaces, which will be the outer side
surfaces of the A/C casing 11 and on which the projections 40 are
not formed. Therefore, the flow rate will not be decreased.
[0096] According to the present embodiment, the multiple
projections 40 are also formed on the plate surface of the guide
plate 51 in the air-mix chamber 26 (which is formed on the wall
surface 11a of the A/C casing 11) as well as on the wall surface
11a at the downstream side of the guide plate 51. The guide plate
51 mixes the cold air and the hot air for the purpose of
controlling the temperature of the air. Therefore, the air currents
collide against the guide plate 51. Furthermore, in the cooling
operation, the guide plate 51 guides the cold air toward the face
door 28. The guide plate 51 changes the direction of the air flow
so as to guide the hot air toward the defroster door without mixing
the cold air and the hot air with each other. When the multiple
projections 40 are formed on the above guide plate 51, the
generation of the aerodynamic sound can be suppressed.
[0097] According to the present embodiment, the multiple
projections 40 are formed on the door surfaces of the air-mix door
23. The air-mix door 23 adjusts the mixing ratio between the cold
air and the hot air depending on the opening degree thereof. The
air currents collide against at least one of the door surfaces
depending on the opening position thereof, so that the direction of
the air flow is changed. When the multiple projections 40 are
formed on the door surfaces of the air-mix door 23, the generation
of the aerodynamic sound can be suppressed.
[0098] In addition, according to the present embodiment, the
multiple projections 40 are formed on the first and second
projection-formed portions 41 and 42, each of which is located at
the downstream side of the heat exchanger, such as the evaporator
20, the heater core 21, and opposes to the heat exchanger. The air
having passed through the heat exchanger 20 or 21 collides against
the first or the second projection-formed portion 41 or 42.
Therefore, the generation of the aerodynamic sound can be
suppressed, when the multiple projections 40 are formed on such
projection-formed portions.
[0099] In addition, according to the present embodiment, the
multiple projections 40 are formed on the third projection-formed
portion 43, which corresponds to the portion of the wall surface
11a of the A/C casing 11 and to which the air from the blower unit
60 is supplied for the first time. The flow rate in this portion is
relatively high. Therefore, the generation of the aerodynamic sound
can be suppressed, when the multiple projections 40 are formed on
such projection-formed portion.
[0100] According to the A/C apparatus 10 for the vehicle, as shown
in FIG. 1, stepped portions are formed in the scroll casing 62 (a
connecting portion between the blower unit 60 and the A/C casing
11) so as to equally supply the air from the blower unit 60 toward
the evaporator 20. The aerodynamic sound is generated at such
stepped portions by the collision of the air currents. Accordingly,
the multiple projections 40 are formed on the connecting portion
between the blower unit 60 and the evaporator 20 (the third
projection-formed portion 43), so that the aerodynamic sound can be
effectively decreased.
[0101] Furthermore, according to the present embodiment, the
multiple projections 40 are formed on the projection-formed portion
63 of the wall surface 62b of the scroll casing 62. According to
the centrifugal-type blower unit 60, the air currents are pushed
out in the centrifugal form and collide against the scroll casing
62, and the air currents flow toward the outlet port which is
gradually expanded. When the air currents are pushed out in the
centrifugal form, the direction of the air currents is changed from
the air drawing direction (the axial direction) to the radial
direction. Therefore, the air currents collide against the portion
of the wall surface of the scroll casing 62, which is located on
the side (the lower side in FIG. 2) opposite to the air drawing
side (the upper side in FIG. 2). Accordingly, when the multiple
projections 40 are formed on such portion 63 of the scroll casing
62, the aerodynamic sound can be decreased. Since the multiple
projections 40 are formed only on the limited portion 63 of the
scroll casing 62, it is possible to suppress the excessive increase
of the frictional resistance between the air currents and the wall
surface. Therefore, the decrease of the flow rate can be
avoided.
[0102] According to the present embodiment, the multiple
projections 40 are further formed on the nose portion 62a, which is
one part of the wall surface 62b of the scroll casing 62 and
corresponds to the volute tongue of the scroll casing 62. The air
currents are unstable at the nose portion 62a and therefore the
directions of the air currents as well as the flow velocity are
momentarily changed. Therefore, the aerodynamic sound can be
decreased when the multiple projections 40 are formed on such wall
surface portion of the nose portion 62a.
[0103] According to the present embodiment, as explained above, it
is possible to decrease the aerodynamic sound, while the increase
of the manufacturing cost is suppressed, while the durability is
maintained, and while the decrease of the flow rate is avoided.
More exactly, it is possible to provide the aerodynamic sound
decreasing apparatus, which can be preferably applied to the A/C
apparatus for the vehicle having the air passages including the
bended portions.
Second Embodiment
[0104] A second embodiment will be explained with reference to FIG.
18. FIG. 18 is a cross sectional view schematically showing a
simplified air passage 13A. A blocking plate 50 is provided on the
wall surface 11a of the air passage 13A, wherein the blocking plate
50 is projecting from the wall surface 11a toward the inside of the
air passage 13A so that it blocks a part of the air currents
passing through the air passage. This kind of plate 50 is provided,
for example, for increasing mechanical strength or for any other
reasons in view of design of various connecting portions. The
multiple projections 40 are formed on the wall surface 11a at a
downstream side of the blocking plate 50 (also referred to as a
flow-change portion), against which the air currents disturbed by
the blocking plate 50 collide. More exactly, the multiple
projections 40 are formed on such portions of the wall surface 11a
at a distance from the blocking plate 50, that is, on the same side
of the wall surface 11a to the blocking plate 50 and on the
opposite side thereof. According to such a structure (the multiple
projections 40), the sound generated by the air currents (disturbed
by the blocking plate 50) can be decreased when colliding against
the flow-change portions of the wall surface 11a.
Third Embodiment
[0105] A third embodiment will be explained with reference to FIG.
19. FIG. 19 is a cross sectional view schematically showing a
simplified air passage 13B. Sealing portions 54 are provided on the
wall surface 11a of the air passage 13B, wherein the sealing
portions 54 are projecting from the wall surface 11a toward the
inside of the air passage 13B so that each of the sealing portions
54 blocks a part of the air currents passing through the air
passage. Incase of the face door 28, an elastic lip seal member 53
is further provided at an outer periphery of the door plate (an
upper side periphery in the drawing), so that the lip seal member
53 is brought into contact with the sealing portion 54, when the
face door 28 is closed. The sealing portions 54 correspond to such
portions, which are in contact with the surface of the face door 28
(the surface of the lip seal member 53), when the face door 28 is
closed to shut off the air passage communicating the inside of the
A/C casing 11 with the passenger compartment. Therefore, the lip
seal member 53 is brought into air-tight contact with the sealing
portions 54 when the face door 28 is closed, so that the air
passage connecting to the face blow-out port 32 can be surely shut
off.
[0106] The multiple projections 40 are provided on the wall surface
11a (the flow-change portions) at the downstream side of the
sealing portions 54, so that the air currents disturbed by the
sealing portions 54 collide against the multiple projections 40. As
in the same manner to the second embodiment, the sound generated by
the air currents (disturbed by the sealing portions 54) can be
decreased when colliding against the flow-change portions of the
wall surface 11a.
Fourth Embodiment
[0107] A fourth embodiment will be explained with reference to FIG.
20. FIG. 20 is a cross sectional view schematically showing a
simplified air passage 13C. As in the same manner to the third
embodiment, the sealing portions 54 and the lip seal member 53 are
provided. The multiple projections 40 are formed on such plate
surface portions of the face door 28 (the flow-change portion),
against which the air currents disturbed by the lip seal member 53
collide when the face door 28 is opened. Accordingly, in the same
manner to the first embodiment, the sound, which is generated by
the air currents (which are disturbed by the lip seal member 53)
when colliding against the face door 28, can be decreased.
[0108] The invention of the present embodiment should not be
limited to such door having the lip seal member 53, but may be
applied to the face door 28 not having the lip seal member 53. In
other words, the multiple projections may be provided on the
portions of the face door 28, against which the air currents
disturbed by the outer periphery of the face door collide.
Therefore, the word "the outer peripheral portion of the door"
includes not only the outer periphery of the lip seal member in the
case of the door having the lip seal member but also the outer
periphery of the door itself in the case of the door not having
such lip seal member.
Fifth Embodiment
[0109] A fifth embodiment will be explained with reference to FIG.
21. FIG. 21 is a cross sectional view schematically showing a
simplified air passage 13D. A rib 55 is provided on the door
surface of the face door 28 for the purpose of reinforcing the
door, wherein the rib 55 is projecting from the door surface.
Rigidity of the face door 28 is increased so that a secular change
can be suppressed.
[0110] The multiple projections 40 are formed on such a plate
surface portion of the face door 28 (the flow-change portion),
against which the air currents disturbed by the rib 55 collide when
the face door 28 is opened. Accordingly, as in the same manner to
the first embodiment, the sound, which is generated by the air
currents (disturbed by the rib 55) when colliding against the face
door 28, can be decreased.
Sixth Embodiment
[0111] A sixth embodiment will be explained with reference to FIG.
22. FIG. 22 is a cross sectional view schematically showing a
simplified air passage 13E. According to the present embodiment,
the aerodynamic sound decreasing member is composed of not the
projections 40 but plate members 56. As in the same manner to the
second embodiment, the blocking plate 50 is provided on the wall
surface 11a of the air passage 13E. The plate members 56 are
provided in the air passage 13E at such portions (the flow-change
portions), which are on the downstream side of the blocking plate
50 and at which the air currents disturbed by the blocking plate 50
collide against the plate members 56. Multiple through-holes 56a
are formed in each plate member 56. Each of the plate members 56 is
so arranged in the air passage 13E at the portions separated from
the wall surface 11a and extends along the wall surface 11a.
According to such a structure, an air layer is formed between the
plate members 56 and the wall surface 11a. Therefore, the
frictional resistance as well as the pressure resistance (the
pressure loss) is generated in the air flow by the plate members 56
and the through-holes 56a, in addition to the frictional resistance
generated by the wall surface 11a. As a result, flow velocity is
low in the plate members 56, while the flow velocity is increased
in the area adjacent to the plate members 56. Namely, the velocity
gradient becomes smaller in the area adjacent to the wall surface
11a, while the velocity gradient is maximized in the area separated
from the wall surface 11a. Accordingly, since the vorticity, which
will cause the aerodynamic sound, becomes smaller and the area of
the maximum vorticity is separated from the wall surface 11a, the
noise (the aerodynamic sound) can be decreased.
[0112] For the purpose of making smaller the velocity gradient in
the area adjacent to the wall surface 11a, it is necessary to
properly set a size of the through-hole 56a, a thickness of the air
layer, a distance between the neighboring through-holes so as to
obtain appropriate frictional resistance and pressure resistance by
the plate members 56. When the size of the through-hole 56a is too
large, sufficient frictional resistance can not be obtained. Then,
the flow velocity of the air currents in the area adjacent to the
wall surface 11a will not be substantially decreased. When the air
layer is too thin, the area for the maximum velocity gradient can
not be sufficiently separated from the wall surface 11a. When the
distance between the through-holes 56a is too large, the sufficient
pressure resistance can not be obtained. Namely, the flow velocity
in the area adjacent to the wall surface 11a can not be
sufficiently decreased.
[0113] When the plate members 56 are provided in the air passage
13E, the sound can be decreased like the multiple projections 40.
The position for the plate members 56 should not be limited to the
position of the present embodiment. For example, the plate members
56 may be provided at such positions (the flow-change portions) of
the above first to fifth embodiments, at which the multiple
projections 40 are formed. The plate member may be formed in a net
shape, in which multiple wires are netted.
(Further Modifications)
[0114] The present invention should not be limited to the above
embodiments, but may be modified in various manners without
departing from the spirit of the invention, as explained below:
[0115] According to the first embodiment, the projection 40 is
formed in the columnar shape. However, the shape of the projection
should not be limited thereto. FIGS. 23 to 37 are perspective
views, each of which shows a modification of the projection 40.
[0116] FIG. 23 shows a first modification, according to which a
projection 40A is formed in a shape of a frustum of a cone, wherein
a root portion is enlarged.
[0117] FIG. 24 shows a second modification, according to which a
projection 40B is formed in a shape of a frustum of a cone, wherein
a root portion is made smaller.
[0118] FIG. 25 shows a third modification, according to which a
projection 40C is formed in a shape of a column, wherein a middle
portion is made smaller.
[0119] FIG. 26 shows a fourth modification, according to which a
projection 40D is formed in a shape of a column, wherein a middle
portion is enlarged.
[0120] FIG. 27 shows a fifth modification, according to which a
projection 40E is formed in a shape of a square pole.
[0121] FIG. 28 shows a sixth modification, according to which a
projection 40F is formed in a shape of a frustum of a quadrangular
pyramid, wherein a root thereof is enlarged.
[0122] FIG. 29 shows a seventh modification, according to which a
projection 40G is formed in a shape of a frustum of a quadrangular
pyramid, wherein a root thereof is made smaller.
[0123] FIG. 30 shows an eighth modification, according to which a
projection 40H is formed in a shape of a square pole, wherein a
middle portion is made smaller.
[0124] FIG. 31 shows a ninth modification, according to which a
projection 40I is formed in a shape of a square pole, wherein a
middle portion is enlarged.
[0125] FIG. 32 shows a tenth modification, according to which a
projection 40J is formed in a columnar shape, wherein a ball-shaped
portion is formed at a forward end of the projection.
[0126] FIG. 33 shows an eleventh modification, according to which a
projection 40K is formed in a columnar shape, wherein a ball-shaped
portion is formed at a middle of the projection.
[0127] FIG. 34 shows a twelfth modification, according to which a
projection 40L is formed in a columnar shape, wherein a half
ball-shaped portion is formed at a root of the projection.
[0128] FIG. 35 shows a thirteenth modification, according to which
a projection 40M is formed in a columnar shape, wherein a forward
end thereof is tapered off.
[0129] FIG. 36 shows a fourteenth modification, according to which
a projection 40N is formed in a columnar shape, wherein a middle
portion is tapered so as to become smaller.
[0130] FIG. 37 shows a fifteenth modification, according to which a
projection 40O is formed in a columnar shape, wherein a root end
thereof is tapered off.
[0131] As explained with reference to FIGS. 23 to 37, the cross
section of the projection may be formed in any kinds of shapes,
such as a circular, an ellipse, a polygon or the like. A concave
portion or a convex portion may be formed at the forward end, the
middle portion or the root of the projection. The forward end
surface of the projection is not limited to the surface, which is
in parallel to the wall surface 11a. The forward end surface of the
projection may be inclined with respect to the wall surface. The
projection may be formed on the wall surface not at a right angle
thereto but at an angle other than 90 degrees (in other words, the
projection may be inclined with respect to the wall surface 11a).
The multiple projections 40 should not be necessarily formed in a
matrix form, but may be formed in a staggered form, in a grid
pattern, in a striped form or the like. Furthermore, the multiple
projections may be formed on the wall surface in a random
order.
[0132] According to the first embodiment, the multiple projections
40 are integrally formed on the wall surface 11a and thereby the
projections have rigidity. However, capillaceous members having
flexibility can be included in the meaning of the projections, and
therefore the capillaceous members may be also provided on the wall
surface.
[0133] According to the above first embodiment, the aerodynamic
sound decreasing members are provided in the A/C apparatus 10 for
the vehicle. However, it is not limited to the A/C apparatus for
the vehicle, but the present invention may be applied to
apparatuses other than the A/C apparatus, for example, an air
blowing apparatus for cooling down various kinds of machines and/or
devices.
* * * * *