JPH0549484B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to noise reduction in automotive air conditioners. [Prior Art] Generally, an air conditioner for an automobile has a resin case 50 forming a ventilation passage, as shown in FIG.
An inside air suction port 60 and an outside air suction port 61 are opened at the most upstream side of the case 50, and both are configured to be switched open and closed by an inside/outside air switching damper (not shown). A blower 51 is provided inside the case downstream of the blower 51.
On the downstream side, there is an evaporator 5 that cools the surrounding air by evaporating the refrigerant of the refrigeration cycle (not shown).
2, and a hot water type heater core 53 which is disposed downstream of this and heats the surrounding air using the cooling water of an automobile engine (not shown) as a heat source. Further, inside the case 50, in addition to an air mix damper 54 for temperature adjustment that changes the ratio of air passing through the heater core 53 and its sidewalls, there are also a plurality of not-shown air mix dampers that open and close the air outlet 55 to change the air outlet state. An air outlet switching damper is provided. The case 50 having the internal configuration described above is disposed in a space between the dashboard board 56 that partitions the engine room A and the vehicle interior B, and the instrument panel 57 across the width direction of the vehicle. Incidentally, in recent years, as vehicles have become more sophisticated and automobile technology has progressed, it has been desired to reduce noise inside the vehicle interior.
Under these circumstances, noise emitted from automobile air conditioners has become a problem. Therefore, the inventors of the present invention investigated the noise emitted from automobile air conditioners and found the following. At that time, a microphone was placed near the ear of the passenger in the driver's seat, and the noise was measured in internal air intake mode. First, the part that makes the most noise is the inside air intake port 6.
It is emitted from zero and accounts for 65% of the noise emitted from all air conditioners. The next one comes from the air outlet 55, which accounts for 26% of the total, and the smallest portion is the one that radiates through the case, which accounts for 9% of the total. Thus, according to the measurement results of the present inventors,
It has been found that among the noises radiated from the automobile air conditioner, the noise from the inside air intake port 60 is the loudest. Based on this experimental result, the inventors investigated the reason and came to the following conclusion. In other words, in conventional automotive air conditioners, the 11th
As shown in the figure, the inside air suction port 60 is opened at a position very close to the blower 51, so when air is taken into the vehicle interior, the inside air suction port 60 opens into the interior B, so the fan of the blower 51 is closed. Wind noise, motor rotation noise of the blower 51, and noise caused by ventilation resistance within the suction system duct are radiated into the vehicle interior through the inside air suction port 60. Furthermore, since the inside air suction port 60 opens near the vehicle side surface 70, the low frequency noise radiated from the inside air suction port 60 is reflected from the vehicle side surface and resonates inside the vehicle interior, so that it is not harmful to the occupants inside the vehicle interior. It turns out that it feels bigger. [Problems to be Solved by the Invention] Therefore, the technical problem of the present invention is to reduce the noise emitted from the inside air intake port, among the noise emitted from the automobile air conditioner. [Means for solving the problems] In order to achieve the above technical problem, the present invention has the following features:
An automotive air conditioner comprising a heat exchanger for heating or cooling air and a ventilation path for supplying air to the heat exchanger inside the case, and the ventilation path is formed across the width direction of the vehicle. a blower installed in the road near the side plate of the vehicle; a suction duct connected to the suction side of the blower and extending toward the center of the vehicle; and an outside air intake port opened in the suction duct. and an inside air suction port provided in the suction duct and opened near a central position of the vehicle; and an inside/outside air switching member that switches the ratio of air introduced from the inside air suction port and the outside air suction port. Adopt technical means. [Operation] According to the above-mentioned technical means, the inside air suction port is opened at a position a predetermined distance away from the blower toward the center of the vehicle through the suction duct, so that the wind noise of the fan generated in the blower area is reduced. , and the motor rotation sound are attenuated as they pass through the suction duct before being radiated from the inside air suction port. Moreover, the opening position of the inside air intake port is on the center side of the vehicle, which is a predetermined distance away from the air blower. far enough away. Therefore, the resonance phenomenon in the vehicle interior of the noise radiated from the inside air intake port is prevented. [Effects of the Invention] Therefore, according to the present invention, the inside air suction port is separated from the noise source and the resonance phenomenon of noise in the vehicle interior is prevented. This can greatly reduce the noise caused by the noise. In addition, it is possible to reduce the part of the noise that traditionally accounts for the highest proportion of the noise emitted from automotive air conditioners, which results in effective noise reduction within the vehicle interior, significantly reducing the noise within the vehicle interior. It has the effect of reducing [Example] Hereinafter, the present invention will be explained with reference to Examples shown in the drawings. FIG. 2 shows a view looking toward the instrument panel from inside the vehicle, and the resin case 1 of the automotive air conditioner in this embodiment is similar to the conventional example shown in FIG. It is arranged in the space between the instrument panel (referred to as the instrument panel) 57 and the dashboard panel, from the center of the instrument panel to the passenger's seat side. An evaporator 52 and a heater core 53 are housed inside the case 1, as in the conventional example shown in FIG. It's summery. Further, a vent outlet 55a is provided on the upper side of the instrument panel to blow out cold air cooled by the evaporator 52 toward the cephalothorax, and a vent outlet 55a is provided below the instrument panel to blow out the cold air cooled by the evaporator 52 toward the cephalothorax. A defroster is provided on the upper surface of the instrument panel to blow hot air heated by the heater core 53 or cold air cooled by the evaporator 51 toward the windshield 58. A blower outlet 55c is provided. The blower 51 is provided close to the vehicle side plate 70 as shown in FIG. 1, and uses a Sirotskov fan having a large number of blades as a fan for blowing air. Therefore, the blower 51 sucks air vertically from above and blows it horizontally, as shown by the arrow in FIG. The suction port 2 of this blower 51 is as shown in FIG.
Vehicle side plate 7 of iron cowl box 3 provided in the upper space between engine room A and vehicle compartment B
It is opened at a position close to 0. In a conventional automobile air conditioner, the cowl box 3 is used as an outside air introduction passage, and serves as a space for storing a wiper link (not shown). As shown in FIG. 3, a heat insulating sheet 32 for soundproofing is attached to the outer surface of the cowl box 3 on the inside of the vehicle interior and the outer surface of the dash board 56 on the inside of the vehicle interior. Further, on the inner surface of the cowl box 3, a heat insulating material 31 such as urethane resin is pasted. Therefore, when the air conditioner performs cooling operation in the inside air mode, the temperature of the cold air in the vehicle interior B drawn into the cowl box 3 from the inside air suction port 4 decreases as it passes through the inside of the cowl box 3. It is inhaled into the suction port 2 without rising. As can be clearly seen from FIG. 2, the inside air intake port 4 is opened on the side surface of the cowl box 3 facing the instrument panel 57, and is located approximately at the center of the instrument panel 57 in the vehicle width direction.
However, the position of this inside air intake port 4 is not necessarily in the center of the instrument panel, but it is preferable to be as far away from the vehicle side plate 70 and the intake port 2 as possible, and at least 1/4 or more of the vehicle width from the vehicle side plate 70 toward the center. It is necessary to provide The outside air intake port 5 is opened in the bonnet near the windshield and communicates with the inside of the cowl box 3, as in the conventional case, but in this embodiment, it is located on the upstream side of the inside air intake port 4. . The inside air suction port 4 is rotatably provided with a damper 6, which is an inside/outside air switching member that opens and closes this. FIG. 4 is an enlarged view of the vicinity of the damper 6. The damper 6 is rotatably attached to a bearing 7 provided on the vehicle body around a shaft 8, and via a link 9 integrated with the shaft 8. wire 10
is attached, and can be moved by an inside/outside air switching lever on the cabin operation panel (not shown). The damper 6 has a shape and structure that can block the introduction of air from the inside air suction port 4 and the outside air suction port 5 communicating with the cowl box 3 depending on its position. Next, the operation of this embodiment having the above configuration will be explained. First, when introducing outside air, if the passenger manually switches the inside/outside air switching lever to the outside air introduction position,
The wire 10 is pulled in the W direction, and the damper 6 rotates and is pressed against the X side of the side surface of the cowl box 3 via the link 9, closing the inside air suction port 4 and opening the passage in the cowl box 3. As a result, the outside air introduced from the outside air suction port 5 is guided to the blower suction port 2 through the cowl box 3 as in the conventional layout. In this case, the outside air suction port 5 is opened to the outside of the vehicle, so the sound radiated from the blower is radiated outside the vehicle, and the noise from the blower is attenuated when passing through the inside of the case 1, and is brought into the passenger compartment. The only noises radiated are wind noise at each outlet 55a, 55b, 55c and noise due to ventilation resistance inside the case 1. Next, when the inside/outside air switching lever is switched to the inside air introduction position, the wire 10 is pulled in the Z direction in FIG. 4, and the damper 6 is pushed toward the Y side via the link 9. Therefore, the passage to cowl box 3 is blocked,
The inside air suction port 4 opens, and the air inside the vehicle compartment is sucked in through the inside air suction port 4, and is guided to the blower suction port 2 through the cowl box 3. In this case, unlike when introducing outside air, the blower 51
The noise radiated from the inside air inlet 4 is emitted into the vehicle interior. However, according to this embodiment, the opening position of the inside air suction port 4 is located near the center of the instrument panel, which is sufficiently far away from the suction port 2 of the blower 51, so that the noise emitted from the suction port 2 passes through the cowl box 3. It is attenuated when Moreover, according to this embodiment, the sound emitted from the intake port 2 is emitted in the vertical direction of the vehicle, but since the cowl box 3 is provided in the horizontal direction of the vehicle, the sound propagation direction is different, and the sound is emitted from the cowl box. It reaches the inside air suction port 4 while reflecting inside the inside air 3. Further, in this example, the inside air suction port 4 is connected to the vehicle side plate 7.
Since it is located in the center of the instrument panel, far enough away from zero, it prevents the resonance phenomenon of low frequency noise of around 200Hz. Therefore, the noise level radiated into the vehicle interior from the inside air intake port 4 is significantly reduced compared to the conventional case. Next, the noise reduction effect in this example will be explained. Fig. 5 shows the noise level distribution in the vehicle interior in a conventional example in which the inside air intake port is provided close to the vehicle side plate and the air intake port, and Fig. 6 shows the noise level distribution in the vehicle interior in a conventional example in which the inside air intake port 4 is provided near the center of the instrument panel. The noise level distribution of this example is shown. In Figures 5 and 6
Marks E ₁ to _{E 5} indicate measurement points near the occupant's ears, and ○ marks schematically indicate the noise level at each measurement point.
Note that E ₁ is the driver's seat, E ₂ is the passenger seat, E ₃ is the right side of the rear seat, E ₄ is the center of the rear seat, and E ₅ is the left side of the rear seat.
Table 1 shows the specific measurement results. However, the measurement frequency was for noise below 200Hz.

[Table] As is clear from this table, according to this embodiment, the noise is reduced by about 2 to 4 dB(A) compared to the conventional example. Next, other embodiments of the present invention will be described. (1) The inside/outside air switching member is not limited to the damper 6 described above, but may be combined with a rotary damper shown in FIGS. 7 to 9. This rotary damper 11
has an inner cylinder 12 and an outer cylinder 13 that slidably accommodates the inner cylinder 12. A shaft 14 is joined to the closed end of the inner cylinder 12, and when the inner cylinder 12 is housed in the outer cylinder 13, the shaft 14 extends outward from a hole 15 opened at the closed end of the outer cylinder. It protrudes and is joined to the link 16. Further, the outer cylinder 13 is provided with two openings 13a and 13b, and the inner cylinder 12 is provided with two openings 13a and 13b.
One opening 12a is provided in the opening 12a. Therefore, when the outer cylinder 13 is disposed in the cowl box 3, if the opening 13a is located upward and the opening 13b faces the inside air suction port 4, then the opening 12a of the inner cylinder 12 is placed upward. When the inner cylinder 12 is rotated, the outside air introduction mode is set as shown in FIG. On the other hand, the inner cylinder 12 is placed in a horizontal position as shown in FIG.
If 2 is rotated, it becomes the inside air introduction mode. (2) The suction duct of the present invention is not limited to the above-mentioned cowl box 3, but as shown in FIG. An opening 19 is provided on the side surface of the box 3, and this opening 19
In addition, a duct 21 for sucking inside and outside air may be provided that protrudes toward the engine room A side. Therefore, in this case, the ventilation path is longer than when the cowl box 3 is used as a suction duct, and since it has a bent part in the middle, the noise level is further reduced. In addition to the above, a suction duct exclusively for inside air is added to the conventional inside air suction port 60 shown in FIG.
It may be connected as a separate body, and the other end may be placed in the center of the instrument panel. (3) If a sound absorbing material such as urethane foam is attached to the inner surfaces of the damper 6 and the cowl box 3, which is the suction duct, the noise reduction effect can be further enhanced. (4) The damper 6 for switching between inside and outside air not only opens and closes the inside air inlet 4 and the outside air inlet 5, but also
It goes without saying that a device that is held at an intermediate position between the inside air suction port 4 and the outside air suction port 5 and sucks both inside air and outside air has the same noise reduction effect as described above. (5) It goes without saying that instead of using the cowl box 3 as a duct as described above, a duct made of a heat insulating material may be provided inside the cowl box 3. (6) The location of the blower is not limited to the vicinity of the vehicle body side plate 70, and even in the case of a suction type blower installed in the center of the instrument panel 57, the upstream end of the case 1 may be opened in the cowl box 3 in the same way as described above. The same applies if

[Brief explanation of drawings]

FIG. 1 is a perspective view of the vicinity of the automobile cowl box showing the features of the present invention, FIG. 2 is a plan view of the instrument panel portion showing the features of the present invention, FIG. 3 is a sectional view taken along line XX in FIG. 1, FIG. 4 is a perspective view of the damper for switching between inside and outside air according to the present invention, FIG. 5 is an explanatory diagram showing the noise distribution inside the vehicle interior using the conventional device, and FIG. 6 is an explanatory diagram showing the noise distribution inside the vehicle interior using the device according to the present invention. , 7th
The figure is an assembly diagram showing another embodiment of the internal/external air switching member of the present invention, FIGS. 8 and 9 are schematic sectional views of FIG. 7, and FIG. 10 is a perspective view showing another embodiment of the suction duct. , FIG. 11 is a schematic cross-sectional view of a conventional automobile air conditioner. 2...Intake port, 3...Cowl box (suction duct), 4...Inside air intake port, 5...Outside air intake port,
6... Damper (inside/outside air switching member), 11... Rotary damper (inside/outside air switching member), 21... Duct (suction duct), 52... Evaporator, 53
... Heater core, 57 ... Air blower, 60 ... Inside air suction port, 61 ... Outside air suction port.

Claims (1)

[Scope of Claims] 1. An automobile comprising a heat exchanger for heating or cooling air and a ventilation passage for supplying air to the heat exchanger inside the case, and the ventilation passage is formed across the width direction of the vehicle. In the air conditioner for a car, the air blower is provided in the ventilation passage and near the side plate of the vehicle; a suction duct connected to the suction side of the blower and extending toward the center of the vehicle; and the suction duct. an outside air suction port that is open to the outside air suction port; an inside air suction port that is provided in the suction duct and that is opened near the center position of the vehicle; An air conditioner for an automobile, comprising: an air switching member. 2. The air conditioner for an automobile according to claim 1, wherein the suction duct is a cowl box of a vehicle. 3. The automobile air conditioner according to claim 2, wherein the inside/outside air switching member is a damper rotatably provided in the cowl box.