JP4051856B2 - Air conditioner for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle air conditioner in which measures for reducing blowing noise are taken.
[0002]
[Prior art]
Conventionally, as a general vehicle air conditioner, for example, an indoor or outdoor air intake port and an air conditioned air discharge port are provided, and a heater core and a cooling heat exchanger as a hot water heat exchanger for heating are provided inside. An air conditioning case containing an evaporator, a blower having a centrifugal fan for letting air flow into the air conditioning case from the suction port, and sending out the air conditioning air from the discharge port, and air conditioning air sent from the air conditioning case What consists of ducts leading into the room is known.
[0003]
As a duct for guiding conditioned air, the necessary ventilation effective area as shown in FIG. 5, in order to avoid the limitation of the mounting space due to the arrangement of structural parts and other mounting parts constituting the vehicle. A duct having a bent portion formed of a smooth R-shaped wall while ensuring the above is known.
[0004]
[Problems to be solved by the invention]
However, in the air conditioner described above, the noise generated by the fan enters the duct from the discharge port of the air conditioning case, and then is radiated from the air outlet into the vehicle interior, causing the quietness of the vehicle interior to be hindered.
[0005]
As shown in FIG. 5, when the noise that has entered the duct 81 reaches the bent portion 90 formed of an R-shaped wall, a part of the noise is absorbed by the inner wall surface of the bent portion 90 on the outer wall 92 side. Although it is converted to thermal energy and dissipated, most of the noise is reflected by the inner wall surface on the R-shaped outer wall 92 side, travels downstream in the duct (air outlet side), and reaches the vehicle interior from the air outlet. It is to do.
[0006]
The present invention has been made in view of the above points, and an object of the present invention is to provide a vehicle air conditioner that can reduce noise radiated into a vehicle interior within a limited range of a vehicle mounting space.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the invention described in claim 1,
An air conditioning case (20) having an inlet (4, 5) at one end and an outlet (36, 37, 38) at the other end;
A blower (11, 19) having a fan (19) for generating a flow of blown air in the air conditioning case (20);
A face duct (41) having a bent portion (50) according to the vehicle shape and guiding the blown air discharged from the discharge port (37) of the air conditioning case (20) to the face outlet (31) in the passenger compartment. In the vehicle air conditioner provided,
The longitudinal section of the face duct (41) is rectangular,
The bent portion (50) has an outer wall (52) and an inner wall (53) of the face duct (41), and the outer wall (52) is provided on one side of the rectangular shape of the face duct (41). And
The inner wall surface (52A) and the outer wall surface forming both surfaces of the outer wall (52) are both a plurality of parallel surfaces (52a) substantially parallel to the inlet surface (50a) of the bent portion (50) and the inlet surface (50a). A plurality of vertical surfaces (52b) substantially perpendicular to each other are formed in a staircase shape,
The noise that has entered the bent portion (50) from the upstream side of the flow of the blown air flows into the bent portion (50) of the inner wall surface (52A) at a plurality of parallel surfaces (52a) substantially parallel to the bent surface (50a). It is characterized by reflecting to the upstream side of the flow .
[0010]
According to this, the noise that has entered the face duct (41) from the air conditioning case (20 ) is substantially parallel to the inlet surface (50a) of the bent portion (50) formed on the inner wall surface (52A) of the bent portion (50). The plurality of parallel surfaces (52a) are reflected to the entrance surface (50a) side of the bent portion (50) and interfere with the incident noise to be attenuated. Therefore, noise radiated from the face outlet (31) into the vehicle compartment can be reliably reduced, and the quietness of the vehicle compartment is improved. In this manner, noise radiated into the vehicle interior can be reduced by the duct (41) having the bent portion (50) arranged within the restriction range of the vehicle mounting space.
[0011]
Further, as in the invention described in claim 2, the face duct (41) can be formed into a hollow shape by blow molding a resin.
[0014]
In addition, the code | symbol in the parenthesis attached | subjected to each said means shows the correspondence with the specific means of embodiment description later mentioned.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
(One embodiment)
FIG. 1 is a schematic configuration diagram schematically showing the configuration of an automotive air conditioner to which the present invention is applied.
[0017]
As shown in FIG. 1, a blower 19 that is a fan driven by a blower motor 11 that generates an air flow in the case 20 is disposed in the air conditioning case 20. Here, the blower motor 11 and the blower 19 constitute a blower. The evaporator 12 is disposed downstream of the blower 19 so as to block the ventilation duct 20, and the evaporator 12 cools the air flow blown out by the blower 19.
[0018]
A heater core 13 is disposed downstream of the evaporator 12 so as to close the air conditioning case 20 by about half, and the heater core 13 reheats the cold air that has passed through the evaporator 12. An air mix damper 21 that adjusts the temperature of the air blown into the vehicle interior by switching the ratio of the air passing through the heater core 13 is disposed upstream of the heater core 13.
[0019]
Further, an upstream side of the blower 19 is provided with an inside air inlet 4 for taking in the inside air and an outside air inlet 5 for taking in the outside air, and an inside / outside air switching damper 6 for switching a ratio of taking in the inside air and the outside air is disposed. .
[0020]
At the most downstream side of the air conditioning case 20, a defroster discharge port 36 that sends out the air whose temperature has been adjusted by the evaporator 12 and the heater core 13 to the defroster outlet 30 that blows out toward the windshield, and a face outlet 31 that blows out toward the upper body of the occupant. And a foot discharge port 38 for sending out to the foot outlet 32 for blowing out toward the feet of the occupant. And the air volume sent out from each of these discharge ports is adjusted by the defroster damper 33, the face damper 34, and the foot damper 35, respectively.
[0021]
Further, the temperature-controlled air sent from each discharge port to each air outlet is guided by the defroster duct 40, the face duct 41, and the foot duct 42, respectively. Hereinafter, a specific configuration of the face duct 41 will be described.
[0022]
The face duct 41 is formed in a hollow shape by blow molding a resin such as polypropylene as shown in FIG. The face duct 41 is open at both ends, and the upstream opening 41 a of the air flow is connected via a packing 44 to a position that substantially coincides with the face discharge port 37 provided in the air conditioning case 20.
[0023]
The downstream opening 41b of the air flow is fitted to the end of the face blowout register 45 constituting the face blowout port 31, and is fixed so as not to drop off by a claw-like snap fit (not shown).
[0024]
The face duct 41 has a rectangular cross section (rectangular in this example), and includes a bent portion 50 and a straight portion 51 that change the direction of air flow. Moreover, in this example, the entrance surface 50a of the bending part 50 exists in the same surface as the upstream opening part 41a. An inner wall 53 on the inner peripheral side of the bent portion 50 is an R-shaped wall as in the conventional face duct shown in FIG. On the other hand, the inner wall surface 52A of the outer wall 52 on the outer peripheral side of the bent portion 50 corresponds to one side of a rectangular shape (rectangular shape), and a plurality of parallel surfaces substantially parallel to the inlet surface 50a of the face duct 41. A stepped wall is formed by alternately arranging the surface 52a and a plurality of vertical surfaces 52b substantially perpendicular to the entrance surface 50a.
[0025]
Even if the shape of the longitudinal section of the face duct 41 is a circle or an ellipse instead of a square shape, the same effect can be obtained as long as the inner wall surface 52A on the outer wall 52 side is stepped as described above. Is obtained.
[0026]
Next, an operation when noise enters the face duct 41 in the above configuration will be described.
[0027]
Noise generated in the blower 19 enters the face duct 41 from the face discharge port 37 of the air conditioning case 20. Part of the noise that has entered the face duct 41 is transmitted toward the downstream opening 41 b by the blown air flowing in the face duct 41, but most of the noise is the entrance surface of the bent portion 50 of the face duct 41. Go straight in the direction perpendicular to 50a.
[0028]
This noise collides with the parallel surface 52a formed on the inner wall surface 52A on the outer wall 52 side substantially perpendicularly. Although some of the impacted noise is absorbed by the parallel surface 52a, converted into thermal energy and dissipated, most of the impacted noise is reflected by the parallel surface 52a and travels toward the face discharge port 37. The noise traveling toward the face discharge port 37 interferes with the noise entering the face duct 41 from the face discharge port 37 and attenuates.
[0029]
Therefore, the noise radiated from the face outlet 31 into the vehicle interior is reduced as compared with the conventional air conditioner, and the quietness in the vehicle interior is improved. Further, since the inner wall surface 52A on the outer wall 52 side of the bent portion 50 of the face duct 41 is formed in a step shape, it does not interfere with the vehicle structural component 60.
[0030]
In this way, it is possible to reduce the noise radiated into the passenger compartment by the duct having the bent portion 50 arranged within the restriction range of the vehicle mounting space.
[0031]
Next, FIGS. 3 and 4 show a confirmation method and a confirmation result of the noise reduction effect of the face duct 41 of the present embodiment performed by the present inventors.
[0032]
As shown in FIG. 3, an upstream opening 41 a of a face duct 41 having a rectangular longitudinal section is connected to a face discharge port 37 provided in the air conditioning case 20, and the air conditioning is separated by 50 mm upstream from the face discharge port 37. A speaker 70 is disposed in the case 20. Further, the microphone 71 is arranged at the center of the upstream opening 41a of the face duct 41, and the microphone 72 is arranged at a position separated by 1000 mm above 45 ° outward from the center of the downstream opening 41b.
[0033]
The inner wall surface 52A on the outer wall 52 side of the bent portion 50 is provided with a stepped wall including a parallel surface 52a parallel to the entrance surface 50a of the face duct 41 and a vertical surface 52b.
[0034]
In this configuration, 70 dB (A) approximating the noise from the blower from the speaker 70 while sending air with an air volume of 150 cubic meters per hour from the upstream side of the air conditioning case 20 to the upstream side opening 41 a of the face duct 41. Oscillated pink noise. This pink noise is obtained by performing frequency correction on pink noise, which is a constant continuous spectrum noise regardless of the frequency, based on an isometric curve.
[0035]
Then, for pink noise from 20 Hz to 10 kHz, the total Lpin of the sound pressure energy was measured with the microphone 71 and the total Lpout of the sound pressure energy was measured with the microphone 72, and the reduced sound volume Lpin-Lpout was calculated.
[0036]
The volume reduction between the case where the face duct 41 of this embodiment is connected to the face discharge port 37 and the case where the conventional face duct 81 having a bent portion whose inner wall surface on the outer wall side is formed in an R shape is connected. The comparison data is shown in FIG. The reduced volume was increased by about 7 dB in the duct of this embodiment compared to the conventional duct.
[0037]
From this result, it can be seen that the duct shape according to the present invention is extremely effective in reducing noise radiated into the passenger compartment.
[0038]
(Other embodiments)
In the above-described embodiment, the noise that has entered the inner wall surface 52A on the outer wall 52 side of the bent portion 50 from the upstream side of the blown air is not reflected to the downstream side, and a plurality of substantially parallel parallel to the inlet surface 50a of the duct 41 is provided. Although a flat surface portion is provided, other structures may be used as long as the intruding noise is not reflected downstream.
[0039]
Further, in the above-described embodiment, the face duct 41 has the entrance surface 50a of the bent portion 50 on the same surface as the upstream opening 41a, but has a straight portion on the upstream side of the bent portion 50. The entrance surface 50a may be a boundary surface between the straight portion and the bent portion 50.
[0040]
Moreover, in the said one Embodiment, although the face duct 41 had one bending part 50, the duct which has two or more bending parts may be sufficient.
[0041]
Moreover, in the said one Embodiment, although the face duct 41 was integrally molded by blow molding, it may divide | segment and shape | mold into 2 or more, and may combine them.
[0042]
Further, in the above-described embodiment, the inner wall surface 52A on the outer wall 52 side of the bent portion 41 of the face duct 41 is configured in a stepped shape, but the same effect can be obtained when applied to a duct having other bent portions. Of course.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram schematically showing the configuration of an automotive air conditioner according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of a main part of a face duct portion of the automotive air conditioner in the embodiment.
FIG. 3 is a schematic configuration diagram showing a confirmation method of a noise reduction effect of the face duct according to the embodiment.
FIG. 4 is a graph of volume reduction showing the confirmation result of the noise reduction effect of the face duct of the embodiment.
FIG. 5 is a schematic cross-sectional view of a main part of a face duct portion of an automotive air conditioner in the prior art.
[Explanation of symbols]
19 Blower 20 Air-conditioning case 31 Face outlet 34 Face damper 37 Face outlet 41 Face duct 41a Upstream opening 41b Downstream opening 45 Face blowing register 50 Bending portion 50a Inlet surface 52 Outer wall 52A Inner wall surface 52a Parallel surface 52b Vertical Surface 60 Vehicle structural parts

Claims (2)

An air conditioning case (20) having an inlet (4, 5) at one end and an outlet (36, 37, 38) at the other end;
A blower (11, 19) having a fan (19) for generating a flow of blown air in the air conditioning case (20);
A vehicle air conditioner having a bent portion (50) according to the vehicle shape, and a face duct (41) for guiding the blown air discharged from the discharge port (37) to a face outlet (31) in the vehicle compartment. In the device
The longitudinal section of the face duct (41) is rectangular,
The bent portion (50) has an outer wall (52) and an inner wall (53) of the face duct (41), and the outer wall (52) has a rectangular shape in the longitudinal section of the face duct (41). Provided on one side,
The inner wall surface (52A) and the outer wall surface forming both surfaces of the outer wall (52 ) are both a plurality of parallel surfaces (52a) substantially parallel to the inlet surface (50a) of the bent portion (50) and the inlet surface. A plurality of vertical surfaces (52b) substantially perpendicular to (50a) are alternately formed in a stepped shape,
Noise that has entered the bent portion (50) from the upstream side of the flow of the blown air flows into the bent surface (52A) at a plurality of parallel surfaces (52a) substantially parallel to the inlet surface (50a) of the inner wall surface (52A). An air conditioner for a vehicle, which is reflected on the upstream side of the flow . The air conditioner for vehicles according to claim 1, wherein said face duct (41) is formed in a hollow shape by blow molding resin .

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