JP2010145003A - Noise reduction structure for duct - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise reduction structure for a duct capable of surely securing a flow channel while suppressing cost, and sufficiently absorbing a sound. <P>SOLUTION: A line A1 connecting an inner side of a curved part of an upper wall turn section 322 formed by bending an internal pathway of an intake duct 3 upward, and an inner side of a curved part of a lower turn section 341 bent downward is determined, a reflecting straight line is determined as a line A2 in a state that the line A1 is for incidence to the upper wall 321 of the internal pathway, a sound absorbing material 8 is positioned on the line A1 at one of both ends in the horizontal direction of its upper end or positioned while cutting across the line A1, and the other end is positioned on the line A2 or positioned while cutting across the line A2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention belongs to the technical field of a duct noise reduction structure.

Conventionally, a sound absorbing material is disposed on the inner wall of the duct (see, for example, Patent Document 1).
JP 2008-14565 A (page 2-7, full view)

  However, conventionally, since the sound absorbing material is attached to the entire inner wall, the parts cost and the work cost are high. Further, when the sound absorbing material on the upper surface side is peeled off, the flow path may be blocked.

  The present invention has been made paying attention to the above-mentioned problems, and the purpose thereof is a duct that can secure a reliable flow path and can sufficiently absorb sound while suppressing cost. It is to provide a noise reduction structure.

  In order to achieve the above object, the present invention is a noise reduction structure for a duct having an internal passage that is bent so that one of both ends of a passage extending in a lateral direction is directed upward and the other is directed downward. It is arranged in a part of the passage extending in the lateral direction of the duct, and includes a sound absorbing material provided with a sound absorbing material, and inside the curved portion where the internal passage of the duct is bent upward, and a curved portion bent downward A first straight line connecting the inside of the inner passage, the first straight line as incident on the upper wall of the internal passage, the reflecting straight line as a second straight line, and the sound absorbing material at one of the lateral ends at the upper end. Is located on the first straight line or located so as to block the first straight line, and the other is located on the second straight line or located so as to block the second straight line. Features.

  Therefore, in the present invention, it is possible to secure a reliable flow path while suppressing cost and to perform sufficient sound absorption.

  Embodiments for realizing the noise reduction structure for a duct according to the present invention will be described in Examples 1 and 3 corresponding to the inventions according to claims 1, 2, 3, and claims 1, 2, 3, 4. A description will be given based on the second embodiment corresponding to the invention.

First, the configuration will be described.
In the first embodiment, a description will be given of an example in which the noise reduction structure of a duct is used as a duct for sending air for cooling a battery for driving a vehicle.
FIG. 1 is an explanatory diagram of the battery cooling device according to the first embodiment.
The battery cooling device 1 includes a suction duct 2, an intake duct 3, a blower 4, an intake duct 5, a battery 6, and an exhaust duct 7.
The suction duct 2 is located behind the rear seat in the vehicle interior and is provided in the rear parcel R that partitions the exterior of the vehicle interior. The suction port 21 at the upper end opens into the vehicle interior and the lower end is positioned inside the trunk room T.

The intake duct 3 has an upper end connected to the lower end of the suction duct 2, a portion for sending air slightly obliquely downward in the left-right direction from this portion, and a lower end directed downward therefrom. Details of the intake duct 3 will be described later.
The blower 4 has a suction port connected to the lower end portion of the suction duct 3 and has an air supply port in the lateral direction. Then, air is forcibly sucked from the suction port by driving the fan, and air is fed from the air supply port.
The intake duct 5 includes an upper end portion having an opening for sucking air from the side, a portion for turning the air duct into a U shape, and a lower end portion having an opening for sending air to the side below the upper end portion. The upper end is connected to the air supply port of the blower 4.

The battery 6 is a battery used for driving the vehicle, and is a high-power battery that stores a voltage of several hundred volts. The battery 6 has a structure having a high-power battery inside the case, and includes a suction port at the upper part of the side surface and a discharge port at the lower part of the side surface below the suction port. Then, the air supply port of the intake duct 5 is connected to this intake port.
The exhaust duct 7 is a duct in which the suction port is connected to the discharge port of the battery 6 and the discharge port of the duct is opened inside the trunk room T. The discharge port may be outside the trunk room T.

Next, the detailed structure of the intake duct 3 will be described.
FIG. 2 is a plan view of the intake duct in the first embodiment. FIG. 3 is a front view of the intake duct in the first embodiment. 4 is a cross-sectional view taken along line BB in FIG. 5 is a cross-sectional view taken along the line AA in FIG.
The intake duct 3 is a duct that includes an intake port portion 31, a passage portion 32, a bag portion 33, and an exhaust port portion 34, has a substantially rectangular cross section, and has a crank-shaped passage.
The intake port portion 31 is a duct portion extending vertically, and the upper end is opened to the outside to be a connection portion to the suction duct 2.
The passage portion 32 is a duct portion that turns the lower end of the intake port portion 31 in the left-right direction and extends in the left-right direction therefrom, and further turns downward in the rear end portion toward the upper end of the exhaust port portion 34. It is a shape to be made. Note that, on the exhaust port portion 34 side of the passage portion 32, that is, on the downstream side, as shown in FIG. 2, the vehicle is curved so as to offset the position in the front-rear direction.
The bag portion 33 is a portion having a shape in which the lower surface of the passage portion 32 is inflated downward.
The exhaust port portion 34 is a duct portion extending vertically, and the lower end is opened to the outside to be a connection portion to the blower 4.

Next, the arrangement structure of the sound absorbing material 8 in the intake duct 3 will be described.
A sound absorbing material 8 is arranged in the intake duct 3 of the first embodiment. The sound absorbing material 8 is made of a material such as sponge or felt, and has a rectangular shape, that is, a thick plate shape.
As shown in FIGS. 4 and 5, the sound absorbing material 8 is placed and fixed on the bag portion 33.
Further, here, in order to describe the arrangement structure of the sound absorbing material 8, the upper wall portion of the passage portion 32 of the intake duct 3 is referred to as an upper wall portion 321. A curved portion that turns the upper wall portion 321 of the passage portion 32 to the intake port portion 31 is referred to as an upper wall turn portion 322.
A curved portion that is turned from the bag portion 33 to the exhaust port portion 34 is referred to as a lower turn portion 341.

And the tangent of the curve of the upper wall turn part 322 and the curve of the lower turn part 341 is set, and it is set as line A1. The line A1 may not be a mathematically exact tangent. Therefore, a description will be added below.
In other words, when facing the intake port portion 31 from the exhaust port portion 34 side, the curve of the lower turn portion 341 and the curve of the upper wall turn portion 322 are seen to overlap each other, and a line connecting them is defined as a line A1. .

With respect to the line A1, the sound absorbing material 8 is arranged so that the corner on the upper side of the flow line is in contact with the line A1 or blocks the line A1. In the first embodiment, the corners are in contact with the line A1. This point is designated as point P1, and is shown in FIG.
Next, the line A1 is considered to be incident, and a line that reflects at the same reflection angle as the incident angle is set as the line A2. And the sound-absorbing material 8 is arranged so that the corner on the upstream side of the flow is in contact with the line A2 or is positioned to block the line A2 with respect to the line A2. In the first embodiment, the corners are in contact with the line A2. This point is designated as point P2, and is illustrated in FIG.

Next, the arrangement structure of the sound absorbing material 8 in the width direction will be described.
In the intake duct 3, the cross-sectional shapes of the passage portion 32 and the bag portion 33 are rounded and substantially rectangular. Since it is formed with a substantially constant plate thickness, both the inner passage and the outer periphery have this shape.
In the width direction of the sound absorbing material 8, the size and arrangement of the sound absorbing material 8 having a gap with respect to the inner walls of the passage portion 32 and the bag portion 33 are set. That is, as shown in FIG. 4, if the distance in the width direction of the passage portion 32 and the bag portion 33 is the width B1, and the width of the sound absorbing material 8 is the width B2, the width B1 is greater than the width B2, and the gaps are formed on both sides. Is provided.
The sound absorbing material may be moved to one side and a gap may be provided on one side.
This gap becomes an air passage. This is a side passage 323.
Furthermore, the width B1 is set to 100%, and the width B2 of the sound absorbing material 8 is set to 75 ± 5%.

The operation will be described.
[Action to secure the flow path reliably while controlling costs]
In Example 1, the rectangular sound-absorbing material 8 is only attached to one portion of the bag portion 33 with respect to the intake duct 3, and the cost and work cost of the sound-absorbing material 8 are greatly suppressed.
Further, the attachment to the bag portion 33 formed on the lower surface of the passage portion 32 of the intake duct 3 is the attachment to the lower surface inside the duct, and even if the joint is peeled off, the bag portion having a shape inflated downward is used. It is located at 33 and does not block the passage portion 32. Further, the passage sectional area of the passage portion 32 is not extremely narrowed.

In the first embodiment, the sound absorbing material 8 is provided in one place as described above, but sufficient sound absorption is performed by disposing the sound absorbing material 8 at a position where sound absorption is effectively performed.
Since the battery cooling device 1 takes in the passenger compartment air as cooling air from the rear parcel R on the rear side of the rear seat, the operating sound of the blower 4 and the wind noise of the cooling air are easily transmitted to the passengers in the rear seat.
For example, the sound emitted from the blower 4 advances from the exhaust port 34 to the inside of the intake duct 3 by a small angle in the left-right direction, comes into contact with the lower turn 341, and tries to go to the intake port 31 without being reflected. In this case, in the intake duct 3 of the first embodiment, since the sound absorbing material 8 is disposed so that the corners are positioned on the line A1, most of the sound traveling at an angle smaller than the angle formed between the line A1 and the left and right direction is sound absorption. It collides with the material 8 and is absorbed.

When the sound emitted from the blower 4 travels from the exhaust port 34 to the inside of the intake duct 3 at an angle larger than the angle formed between the line A1 and the left and right directions, the sound is reflected by the upper wall portion 321 of the passage portion 32. And proceed. Then, most of them collide with the sound absorbing material 8 and are absorbed. For example, when it is going to exceed the sound absorbing material 8 by being reflected by the upper wall portion 321 of the passage portion 32, it always collides with the upper surface of the sound absorbing material 8 when the angle is larger than the angle formed by the line A1 and the left-right direction. Even when the sound advances at a slightly larger angle than the line A1 and does not collide with the point P1 of the sound absorbing material 8, the sound reflected by the upper wall portion 321 or the upper wall turn part 322 is slightly different from the line A2 reflected by the line A1. Since it is large, it collides near the point P2 of the sound absorbing material 8 and is absorbed.
Thus, in Example 1, it arrange | positions so that most of the sound emitted from the blower 4 may contact | abut the sound-absorbing material 8, and it absorbs sound efficiently.

In the first embodiment, as shown in FIG. 4, the sound absorbing material 8 is provided so as to provide a gap on both sides with respect to the width of the passage portion 32 and the bag portion 33.
Thereby, the attachment work of the sound absorbing material 8 becomes very easy.
In the battery cooling device 1 according to the first embodiment, a controller (not shown) detects the temperature, current, and voltage of the battery 6 to control the blower 4 so that a necessary amount of cooling is performed. In the battery cooling device 1, this cooling is performed by introducing air in the passenger compartment that is air-conditioned by the vehicle air conditioner.

Therefore, in order to perform strong cooling, it is controlled to suck a lot of air. Therefore, if the volume of the sound-absorbing material 8 is increased too much, the substantial flow path including the loss coefficient is reduced, so that the drive speed of the blower 4 is increased. Depending on the degree, the driving speed of the blower 4 is increased, so that the operating noise increases, and the quietness of the battery cooling device 1 decreases.
Further, increasing the surface area of the sound absorbing material 8 facing the inside of the air passage increases the sound absorbing effect because the sound absorbing area increases. However, if the width of the side passage 323 is excessively increased, the sound that passes without colliding with the sound absorbing material 8 is increased.

Therefore, in the first embodiment, the ratio of the width B2 of the sound absorbing material 8 to the width B1 of the passage portion 32 and the bag portion 33 is obtained by an experiment so that the blower 4 is controlled close to an actual vehicle. In other words, the width of the side passage 323 is obtained through experiments.
FIG. 6 is a graph showing the relationship between the ratio of the width of the sound absorbing material to the duct flow path width in Example 1 and the noise reduction effect.
The ratio of the width B2 of the sound absorbing material 8 to the width B1 reaches a peak at about 75%, and thereafter the noise reduction effect decreases. This characteristic gently peaks. For this reason, it is desirable that the portion having a high noise reduction effect is 75% ± 5% where the characteristic curve is gentle. Thereby, the effect which suppresses that a sound is further transmitted to a passenger | crew is heightened.

  That is, in the first embodiment, the width B2 of the sound absorbing material 8 is set to 75% ± 5% with respect to the width B1, so that the most effect can be obtained, and the characteristic is not changed extremely with respect to the dimensional change or the like. The blower 4 can be driven silently, and the effect of suppressing the sound from being transmitted to the occupant is enhanced.

In the intake duct 3 according to the first embodiment, as described above, the cost is suppressed, and the sound absorbing material 8 is provided only on the lower surface of the duct passage to effectively absorb the sound. It will be explained that this sound absorbing structure has a sufficient effect.
FIG. 7 is a graph showing the frequency characteristics of sound measurement data in which the sound absorption effect of the intake duct in Example 1 is confirmed.
In FIG. 7, the line denoted by reference numeral 100 is the sound data of the intake duct 3 without the sound absorbing material 8, and the line denoted by reference numeral 101 is the sound data of the intake duct 3 in the state where the sound absorbing material 8 of the first embodiment is provided. . As is clear from FIG. 7, the sound absorbing material 8 absorbs a high-frequency sound that is easy to be transmitted to the occupant without being easily covered by the traveling sound during traveling of the vehicle.

Explain the effect.
In the duct noise reduction structure of the first embodiment, the effects listed below can be obtained.

  (1) Intake duct 3 having an internal passage that bends one side of both ends of passage portion 32 extending in the lateral direction upward to form intake port portion 31 and the other to downward and forms exhaust port portion 34. The noise reduction structure is provided in a bag portion 33 of a passage portion 32 extending in the lateral direction of the intake duct 3 and includes a sound absorbing material 8 made of a sound absorbing material, and the internal passage of the intake duct 3 is directed upward. A line A1 connecting the inside of the curved portion of the bent upper wall turn portion 322 and the inside of the curved portion of the lower turn portion 341 bent downward is set, and the line A1 is incident on the upper wall portion 321 of the internal passage. A straight line to be reflected is set as a line A2, and the sound absorbing material 8 is arranged such that one of the lateral ends at the upper end is located on the line A1 or is located so as to block the line A1, and the other is located on the line A2. To block A2 Since arranged to, while suppressing the cost, it is possible to ensure a reliable flow path.

  (2) In the above (1), the sound absorbing material 8 forms the side passage 323 outside the at least one side surface in the front-rear direction, and the side surface in the front-rear direction faces the side passage 323. Sufficient sound absorption can be performed by securing the passage so that the blower 4 can sufficiently flow by silent driving and absorbing sound by this surface at an appropriate interval.

  (3) In the above (2), the sound absorbing material 8 forms side passages 323 on both sides in the front-rear direction, and the width of the sound absorbing material 8 in the front-rear direction is set to 75 ± with respect to the internal passage width of the intake duct 3. Since it is 5%, the blower 4 can be driven silently, and the effect of suppressing the sound from being transmitted to the occupant can be enhanced.

The second embodiment is an example in which a sound absorbing material is provided in the turn portion to the intake port portion.
The configuration will be described.
FIG. 8 is a partially cutaway sectional view of the intake duct of the second embodiment. FIG. 9 is a cross-sectional view of the intake duct of the second embodiment. (The cross-sectional line is the AA cross-sectional line in FIG. 2)
In the second embodiment, the passage portion 32 is turned upward so as to connect the lower end of the intake port portion 31 and the passage portion 32 extending in the left-right direction, and the outer peripheral side of the upper wall turn portion 322, that is, the turn portion The outer peripheral side is a lower wall turn part 324.

Further, the distance in the vertical direction from the upper end opening of the air inlet 31 to the upper corner of the sound absorbing material 8 on the air inlet 31 side is defined as a distance L1. Further, a distance in the vertical direction from the upper end opening of the intake port 31 to a position where the upper wall portion 321 of the passage portion 32 is extended is a distance L2.
Then, along the lower wall turn portion 324, the sound absorbing material 9 is provided in a shape obtained by curving a plate shape having a predetermined thickness. The material of the sound absorbing material 9 is the same as that of the sound absorbing material 8. The sound absorbing material 9 has an end on the downstream side in contact with or close to an end on the intake port 31 side of the sound absorbing material 8, and an upstream end located above and below the upper end opening of the intake port 31. The size and shape are such that the direction distance L is shorter than the distance L1 and the distance L2.
Since other configurations are the same as those of the first embodiment, description thereof is omitted.

The operation will be described.
In the second embodiment, by providing the sound absorbing material 9 in addition to the sound absorbing material 8, the sound generated by the blower 4 is further prevented from being transmitted to the vehicle occupant.
In order to further improve this, a route through which the sound from the blower 4 is transmitted, and a route without the sound absorbing material 8 is considered. The upper portion of the portion for turning the passage portion 32 to the exhaust port portion 34 is referred to as an upper turn portion 342. Then, the sound emitted from the blower 4 is reflected by the curved portion of the upper turn portion 342, passes through the passage portion 32 without colliding with the sound absorbing material 8, is reflected by the lower wall turn portion 324, and is the intake port portion 31. You can think of a route to

Therefore, in Example 2, the sound absorbing material 9 is provided on the lower wall turn portion 324 to further absorb sound. Further, by making the upper end of the sound absorbing material 9 shorter than the distance L1 and the distance L2, the path from which the sound goes from the blower 4 to the vehicle interior without colliding with the sound absorbing material 9 is eliminated, and sound absorption is more reliably performed.
Further, since the sound absorbing material 9 is provided at a position close to the intake port portion 31, the work of attaching is very easy.
In addition, the sound absorbing material 9 is provided on the upstream side of the sound absorbing material 8, that is, on the vehicle interior side, so that the sound that is transmitted to the vehicle interior side other than the above-described route and the sound that the sound absorbing material 8 is transmitted without being absorbed. Therefore, the sound absorption is further increased.

Explain the effect. In the noise reduction structure for a duct according to the second embodiment, the effects listed below can be obtained in addition to the above (1) to (3).
(4) In the above (1) to (3), since the sound absorbing material 9 is provided on the lower wall turn portion 324 outside the curved portion where the passage portion 32 of the intake duct 3 is bent upward, the sound is transmitted to the occupant. The suppression effect can be enhanced.

(5) In the above (4), since the upstream end of the sound absorbing material 9 has a vertical distance from the upper end opening of the air inlet 31 that is shorter than the distance L1 and the distance L2, the lower wall turn portion It can be further ensured that the sound reflected at 324 reliably collides with the sound absorbing material 9 and the effect of suppressing the sound from being transmitted to the occupant is enhanced.
Since other functions and effects are the same as those of the first embodiment, description thereof is omitted.

Example 3 is an example in which the lower surface of the sound absorbing material is recessed upward.
The configuration will be described.
FIG. 10 is a cross-sectional explanatory view of the structure of the intake duct of the third embodiment. (The cross-sectional line is the same as the AA cross-sectional line in FIG. 2)
In the third embodiment, the sound absorbing material 20 is provided in the intake duct 3. The sound absorbing material 20 is provided with a flat plate portion 201, and an inclined portion 202 that is inclined obliquely downward at an upstream end portion of the flat plate portion 201 so that the flat plate portion 201 provides a lower surface and a gap, and a downstream side of the flat plate portion 201. An inclined portion 203 that is inclined obliquely downward is provided at the end on the side.
Then, the point P1 with respect to the line A1 and the point P2 with respect to the line A2 are satisfied at the corners of the connecting portions of the flat plate portion 201, the inclined portion 202, and the inclined portion 203.
Since other configurations are the same as those of the first embodiment, description thereof is omitted.

The operation will be described.
In the third embodiment, a space is provided between the lower surface of the flat plate portion 201 and the bag portion 33, and the space communicates with the side passage 323 to further increase the surface area of the sound absorbing material 9 facing the space. . And the volume of sound-absorbing material itself is suppressed, and it is made to contribute to cost further.
Further, by making the sound absorbing material 20 thin, insertion into the intake duct 3 is facilitated and workability is improved.

Explain the effect. In the noise reduction structure for a duct according to the third embodiment, the effects listed below can be obtained in addition to the above (1) to (3).
(6) Since the sound absorbing material 20 has the bottom surface recessed and communicated with the side passage 323, the sound absorbing surface area can be increased and the effect of suppressing the sound from being transmitted to the occupant can be enhanced.

  As mentioned above, although the noise reduction structure of the duct of this invention has been demonstrated based on Example 1-3, it is not restricted to these Examples about a concrete structure, Each claim of a claim Design changes and additions are permitted without departing from the spirit of the invention according to the paragraph.

  For example, in Example 2, the end L on the upstream side of the sound absorbing material 9 is set such that the vertical distance L from the upper end opening of the air inlet 31 is shorter than the distance L1 and the distance L2, but the distance L is short. In addition, it is preferable that the distance L is shorter than the distance L1 and the distance L2. For example, the passage portion 32 may be inclined. In this case, when the extension of the upper wall portion 321 reaches the opening of the intake port portion 31, it is difficult to set the distance L2, but the distance L is shortened. Anything to do.

  Further, for example, in Example 2, the sound absorbing material 9 is provided separately from the sound absorbing material 8, but may be integrated.

It is explanatory drawing of the battery cooling device of Example 1. FIG. 2 is a plan view of an intake duct in Embodiment 1. FIG. 2 is a front view of an intake duct in Embodiment 1. FIG. It is BB sectional drawing of FIG. 5 is a cross-sectional view taken along the line AA in FIG. It is a graph which shows the relationship between the ratio of the width of the sound absorption material with respect to the duct flow path width in Example 1, and the noise reduction effect. It is a graph which shows the frequency characteristic of the sound measurement data which confirmed the sound absorption effect of the air intake duct in Example 1. 6 is a partially cutaway cross-sectional view of an intake duct according to Embodiment 2. FIG. 6 is a cross-sectional view of an intake duct according to Embodiment 2. FIG. FIG. 6 is a cross-sectional explanatory diagram of the structure of an intake duct of Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery cooling device 2 Suction duct 21 Suction port 3 Intake duct 31 Intake port part 32 Passage part 321 Upper wall part 322 Upper wall turn part 323 Side wall 324 Lower wall turn part 33 Bag part 34 Exhaust port part 341 Lower turn part 342 Upper turn part 4 Blower 5 Intake duct 6 Battery 7 Exhaust duct 8 Sound absorbing material 9 Sound absorbing material 20 Sound absorbing material 201 Flat plate part 202 Inclined part 203 Inclined part C Car compartment R Rear parcel T Trunk room

Claims (4)

A noise reduction structure for a duct having an internal passage that is bent so that one of both ends of a passage extending in a lateral direction is directed upward and the other is directed downward.
It is disposed in a part of the passage extending in the lateral direction of the duct, and includes a sound absorbing material provided with a sound absorbing material,
Setting a first straight line connecting the inside of the curved portion bent upward of the internal passage of the duct and the inside of the curved portion bent downward;
The first straight line is incident on the upper wall of the internal passage, the reflecting straight line is set as the second straight line,
The sound absorbing material is configured such that one of both ends in the lateral direction of the upper end is located on the first straight line, is located so as to block the first straight line, and the other is located on the second straight line, or the second Arranged so as to block the straight line,
A duct noise reduction structure characterized by that. The noise reduction structure for a duct according to claim 1,
The sound absorbing material is
A side passage is formed outside at least one side surface in the front-rear direction, and a side surface in the front-rear direction faces the side passage.
A duct noise reduction structure characterized by that. In the noise reduction structure for a duct according to claim 2,
The sound absorbing material is
Side passages were formed on both sides in the front-rear direction, and the width of the sound absorbing material in the front-rear direction was 75 ± 5% with respect to the internal passage width of the duct.
A duct noise reduction structure characterized by that. In the noise reduction structure for a duct according to any one of claims 1 to 3,
A sound-absorbing material is provided in a curved portion where the internal passage of the duct is bent upward.
A duct noise reduction structure characterized by that.

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