US20070045042A1

US20070045042A1 - Sound reduction system with sound reduction chamber

Info

Publication number: US20070045042A1
Application number: US11/467,185
Authority: US
Inventors: William Barz; Henry Richardson
Original assignee: L&L Products Inc
Current assignee: Zephyros Inc
Priority date: 2005-08-25
Filing date: 2006-08-25
Publication date: 2007-03-01

Abstract

A sound reduction system is provided. The system is preferably designed to allow air or other fluid to flow through the system while lessening the amount of sound flowing through the system.

Description

CLAIM OF PRIORITY

This application claims the benefit of the filing date of U.S. Provisional Application No, 60/711,101 filed Aug. 25, 2005.

FIELD OF THE INVENTION

The present invention relates generally to a sound reduction system and a method of using the system to reduce noise for articles of manufacture such as transportation vehicles (e.g., automotive vehicles, trains or the like)

BACKGROUND OF THE INVENTION

For many years, industry (e.g., the transportation industry) has been concerned with designing systems for limiting the transfer of sound to certain locations such as the passenger compartment of an automotive vehicle. In certain instances, however, it can also be desirable for these systems to allow a fluid such as air to flow through the system while still maintaining the ability of the system to limit sound transfer. For example, it may be desirable for air to flow through a system in order to relieve elevated air pressure in a passenger compartment of an automotive vehicle (e.g., when a door of that vehicle is closed or the HVAC system is turned on). Thus, the present invention seeks to provide a system that limits sound transfer, but which also allows a fluid such as air to flow through at least a portion of the system.

SUMMARY OF THE INVENTION

A system for reducing the passage of sound from a first location to a second location is disclosed. The system typically includes a structure of an article of manufacture and a housing adjacent the structure and adjacent a fluid flow path. The flow path typically allows fluid flow from the first location to the second location and the flow path is typically adjacent a chamber such that sound can enter the chamber, reflect of one or more walls of the chamber and be canceled. The system has been found particularly effective for reducing noise in automotive vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and inventive aspects of the present invention will become more apparent upon reading the following detailed description, claims, and drawings, of which the following is a brief description:
FIG. 1 is a perspective view of an exemplary sound reduction system according to one aspect of the present invention.
FIG. 2 is a sectional view of the exemplary sound reduction system of FIG.
FIG. 3 is a perspective view of a portion of the exemplary chamber of a sound reduction system according to an aspect of the present invention.
FIG. 4 is a side view of the exemplary sound reduction system of FIG. 1 being assembled to an exemplary structure of an article of manufacture.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is predicated upon providing a sound reduction system for reducing the amount of sound passing from a first location to a second location. The sound reduction system has found particular utility for automotive vehicles although it is contemplated that the system may be applied to a variety of articles of manufacture such as airplanes, boats, buildings, furniture, appliances or the like.
Accordingly, the system of the present invention typically includes one or more of the following:

- 1) a structure of an article of manufacture (e.g., an automotive vehicle) that preferably includes a wall having an opening;
- 2) a housing configured for attachment to the structure wherein: the housing typically substantially surrounds a chamber; the housing typically includes one or more openings (e.g., a first opening and a second opening) in fluid communication with the chamber; and the chamber is typically located beside a path through or connecting the one or more openings; and
- 3) optionally, a seal is associated with the housing and configured for sealing between the housing and the structure of the article of manufacture.

Typically, the system is designed such that sound waves entering the housing are reflected off of one or more walls defining the chamber. After refection, the reflected sound waves interact (e.g., collide) with other sound waves (e.g., incoming sound waves), reflected or non-reflected, entering or moving within the chamber. Typically, and without being bound by any particularly theory, the interaction of these sound waves tends to cancel or otherwise at least partially destroy the sound waves thereby reducing the amount of sound exiting the housing relative to the amount of sound entering the housing.
Referring to FIGS. 1-3, there is illustrated an exemplary system 10 according to an aspect of the present invention. The system 10 is generally designed for reducing sound, particularly undesirable noise, within an article of manufacture such as an automotive vehicle. The system includes a housing 12 surrounding a substantial portion (e.g., at least 50%, 70%, 90% or more) or substantially the entirety of an internal chamber 14. The housing 12 additionally includes (e.g., defines) one or more openings 16, 18. As used herein, the housing can be any member or structure or group of members or structures that surround and/or define a substantial portion of an internal chamber.
Housing will typically have no specific shape unless otherwise specifically recited. It should also be noted that the housing may include pad of the structure to which it is installed (as is described further below). For example, a portion of the housing may generally define a cavity, but may only substantially surround the internal chamber when that portion of the housing is attached to a wall of a structure such that the wall completes the housing such that the housing substantially entirely surrounds the internal chamber.
The illustrated housing 12 is shaped as a rectangular box with five sides. The housing may be formed of a variety of materials such as polymeric materials (e.g., plastics), metals, glass, fibrous materials, combinations thereof or the like.
The one or more openings of the system or housing will typically assist in providing a flow path for allowing fluid to flow therethrough. Moreover, the one or more openings will typically be in fluid communication with the chamber of the housing. In the embodiment illustrated, the housing includes a first opening 16 in fluid communication with a second opening 18. As illustrated by a curved or bent arrow 22, a fluid flow path interconnects or provides fluid communication between the first opening 16 and the second opening 18.
The chamber of the system is typically in fluid communication with the one or more openings of the housing or system and the chamber is configured for receiving sound (i.e., sound waves) that enter the housing through the one or more openings. The chamber is typically located adjacent (e.g., beside) the flow path created by the one or more openings. In the embodiment of FIGS. 1, 2 and 4, the chamber 14 is located beside the path 22 traveling from the first opening 16 to the second opening 16. Moreover, the exemplary chamber 14 is located closer to a first end 26 of the housing 12 relative to both the first and second openings 16, 18.
It is contemplated that the chamber may have a single consistent or multiple different depths relative to the one or more openings of the housing. As used herein, a depth or depths of the chamber are distances between the one or more openings to one or more rear walls. Typically, a depth can be measured as the length of a line segment that extends from a rear wall to a closest center point of the closest of the one or more openings. The center point is a point at which the line segment extends half way across the openings. Such a depth measurement is labeled (D) in FIGS. 1 and 2. A single consistent depth can be achieved by having a rear wail (i.e., a wall furthest from the one or more openings) that is substantially consistently equidistant (i.e., within 5 cm, more typically within 2 cm and even more typically within 1 cm of equidistant) from the center points of the one or more openings. Such a rear wall 30 is illustrated in the embodiment of FIGS. 1 and 2 and such wall 30 is substantially equidistant at a distance (D) from the opening 18 of the housing 12.
In the particular embodiment illustrated, the housing 12, the chamber 14 or both are divided into multiple sub-chambers 34 by one or more (e.g., 1, 2, 3, 4, 5, or more) divider walls 36. Each sub-chamber 34 provides access to the rear wall and/or extends from the openings 16, 18 to or toward the rear wall 30.
As suggested, the chamber of the present invention may have multiple depths. Multiple depths can be achieved by angling or contouring the rear wall or, alternatively, providing multiple rear walls at multiple different distances from the one or more openings. Advantageously, whether using a single or multiple depths, the chamber can be tuned for diminishing or canceling certain undesirable sound or noise as discussed further below. A chamber 40 of FIG. 3 is illustrated to include multiple rear walls 42, 44, 46, 48, 50 at multiple depths.
Optionally, the sound reduction system of the present invention may include a sealing material for attaching and/or sealing the system or housing to a structure of an article of manufacture. The system 10 of FIGS. 1-3 includes a sealing material 56 extending about an attachment 58 of the housing 12 or system 10. In the exemplary embodiment illustrated the sealing material 56 extends substantially continuously about the attachment 58. Generally, the skilled artisan will be able to think of several attachments and/or sealing materials that may be employed within the scope of the present invention.
The sealing material may be formed of a variety of materials since, as the skilled artisan would recognize, many different suitable sealing materials have been or will be developed. As one example, the sealing material may be formed of material including or substantially entirely comprised of a polymeric material that includes an elastomer, a plastic or a combination thereof.
In one preferred embodiment, the sealing material is formed of an activatable material. Various activatable materials may be employed in the present invention. For example, a heat activated material having foamable characteristics may be employed. The material may be generally dry to the touch or tacky and can be placed upon or adjacent any of the components of the housing or system in any form or desired pattern, placement, or thickness. Exemplary materials include L-5248, L-7002, L-7102, L-7104, L2105 and L-5204 foams available through L&L Products, Inc. of Romeo, Mich.
A number of reinforcing, sealing and/or baffling materials are known in the art and may also be used to produce foam. A typical foam includes a polymeric base material, such as an epoxy resin, an ethylene-based polymer, an acrylate and/or acetate based material or a combination thereof which, when compounded with appropriate ingredients (typically a blowing and curing agent), expands and cures in a reliable and predictable manner upon the application of heat or the occurrence of a particular ambient condition. From a chemical standpoint for a thermally-activated material, the structural foam is usually initially processed as a flowable thermoplastic material before curing. Typically, the material will cross-link upon curing (e.g., become thermoset), which makes the material incapable of further flow.
Examples of preferred foam formulations are EVA based and epoxy-* based materials that are commercially available from L&L Products of Romeo, Mich., under the designations L7220, L5206, L5207, L5208, L5209, L5218, L5224, L-5248, XP321 and XP721. Other suitable sealing materials include elastomeric materials (e.g., elastomeric gaskets). Additional materials include polyurethanes or other materials all of which may be formed into gaskets or other configurations.
The system of the present invention may be employed in several different articles of manufacture as previously discussed. Thus, the system may be assembled to multiple different structures For exemplary purposes, however,
the system 10 of FIGS. 1-2 is shown as being assembled to a structure 70 (e.g., a pillar or rearward wall of a passenger compartment) of an automotive vehicle (e.g., a car, a truck, an SUV or the like) in FIG. 4.
Preferably, although not required, the structure to which the system is assembled will be configured for allowing the passage of a fluid (e.g., air) between a first location within the article of manufacture and a second location within the article of manufacture or external to the article of manufacture. For example, a pillar structure or other structure (e.g., a rearward passenger compartment wall) of an automotive vehicle may have an opening in fluid communication with an interior space or cabin (e.g., passenger compartment) of an automotive vehicle and in fluid communication with an external or ambient environment surrounding the vehicle. In this manner, air can flow into or out of it the interior cabin for avoiding undesirable low or high levels of pressure within the interior cabin. Generally, the system of the present invention is installed to such a structure such that the fluid or air flow is directed through the one or more openings of the housing or system.
In FIG. 4, the structure 70 illustrated is in fluid communication with an interior cabin of a vehicle and an exterior environment surrounding the vehicle through one or more openings 74 in the structure 70. The system 10 is installed to the structure 70 by attaching the housing 12 to the structure 70 such that the one or more opening 16, 18 of the housing are in fluid communication with the opening 74 of the structure 70. In the embodiment illustrated, the attachment 58 is interference fit within the opening 74 of the structure 30 thereby aligning and allowing fluid communication between the opening 74 of the structure and the second opening 18 of the housing 12. Such attachment also places the first opening 16 of the housing 12 in fluid communication with an external or ambient environment 80 surrounding the vehicle. Thus, both the first opening 16 and the second opening 18 are in fluid communication with the passenger compartment and the ambient environment Once installed, the first and second openings 16; 18 of the housing 12 may be in fluid communication with the passenger compartment directly or through second any openings (not shown) in the structure or other par of the vehicle.
Preferably, upon installation, the sealing material 56 creates a substantially fluid tight seal between the structure 70 and the housing 12 and/or attachment 58 thereby encouraging any flow of air to go through the openings 16, 18 of the housing 12. Such a seal may be created by interference fitting the attachment, the sealing material 56 or both with the opening 74 of the structure 70. When an activatable material is employed as the sealing material, the activatable material is typically heat activated (e.g., in a paint or e-coat bake oven) to expand (e.g., foam) and cure thereby adhering the material to the structure, the housing or both. It is also contemplated that the system, and particularly the housing, may be attached additionally or alternatively to the structure with one or more fasteners (e.g., mechanical fasteners such as push pins, brackets and screws or others).
Advantageously, the system of the present invention can be employed in a situation where it is desirable to inhibit the transmission of sound while still allowing the flow of a fluid such as air therethrough. For example, in FIG. 4, the structure 70 of the vehicle remains in fluid communication with the interior cabin (e.g., passenger compartment) of the vehicle and in fluid communication with an ambient environment 80 surrounding the vehicle as discussed. Thus, for is example, upon closing of a vehicle door, use of an air conditioning system or the like, air from the interior cabin can flow to the ambient environment thereby avoiding an undesirable elevated pressure within the cabin of the vehicle. In addition, sound waves (e.g., noise) from the ambient environment or other locations of the vehicle that go into the housing (typically through the first opening 16) will typically go into the chamber 14. These sound waves will then be reflected within the chamber 14 (e.g., off of one or more rear walls) and such sound waves will tend to cancel or reduce each other thereby limiting the amount of sound that travels to the cabin of the vehicle.
As is known, sound waves can have many different frequencies. Thus, as an added advantage to the system of the present invention, the chamber 14 can be designed to target reduction of particular frequencies. It has been found that the depth (D) or depths (e.g., D₁, D₂, D₃, D₄) of the chamber 14 can be tuned to target particular frequencies. Generally, it is believed that the depth (D) or depths (e.g., D₁, D₂, D₃, D₄) should be ¼ of the wavelength of the sound or noise that it is desirable to cancel. Thus, a single depth can be employed for significantly reducing sound waves of one particular range of frequencies while multiple depths can be employed for reducing sound waves of multiple different frequency ranges.
Setting a depth to ¼ of a particular wavelength will typically assist in canceling noise at a particular frequency of the wavelength and a range of frequencies above and below that particular frequency. Thus, the system is not limited to canceling only sound at the particular frequency that corresponds to the wavelength for which the depth is ¼ that wavelength but can cancel ranges of sound.

For guidance the following table is provided for assisting in determining the depth or depths suitable for the chamber when targeting certain frequency ranges:

TABLE


Frequencies (Hz)	Wavelengths (m)	Depths (m)

250 ± 10%	1.360 ± 20%	0.340 ± 30%
500 ± 10%	0.680 ± 20%	0.170 ± 30%
800 ± 10%	0.425 ± 20%	0.106 ± 30%
1000 ± 10%	0.340 ± 20%	0.085 ± 30%
2000 ± 10%	0.170 ± 20%	0.043 ± 30%
4000 ± 10%	0.085 ± 20%	0.021 ± 30%

For the present invention, the use of ±a percentage means plus or minus the percentage of that number. For example 100±30% means 70 to 130. One particularly desirable range or frequencies that are desirable to eliminate are in the 800±20% Hz.
In addition to the above, it is contemplated that the sound reduction system may include other features as well. For example the one or more openings of the housing may be covered with actuation or moving members such as flaps. Such member would typically cover the one or more openings until air pressure gradients cause the members to move and uncover the openings such that air can flow through the openings. It is also contemplated that one or more masses of material such as foam or activatable material may be located within the chamber for assisting in absorbing sound.
Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. Plural structural components can be provided by a single integrated structure. Alternatively, a single integrated structure might be divided into separate plural components. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention.
The preferred embodiment of the present invention has been disclosed. A person of ordinary skill in the art would realize however, that certain modifications would come within the teachings of this invention. Therefore, the following claims should be studied to determine the true scope and content of the invention.

Claims

1. A system for reducing the passage of sound from a first location to a second location, the system comprising;

a structure of an article of manufacture; and

a housing adjacent the structure and adjacent a fluid flow path, the housing defining a chamber, wherein.

i. the flow path allows fluid flow from the first location to the second location; and

ii. the flow path is adjacent the chamber such that sound can enter the chamber, reflect of one or more walls of the chamber and be canceled.

2. A system as in claim 1 wherein the housing is substantially entirely formed of plastic.

3. A system as in claim 1 wherein the housing is attached to the structure and includes an opening aligned with an opening of the structure and seal provides sealing between the housing and the structure at the opening of the housing, the structure or both.

4. A system as in claim 1 wherein the housing defines a first opening and a second opening along the fluid flow path.

5. A system as in claim 1 wherein the housing defines a rear wall that has a depth (D) from the entry location into the chamber of 0.106 meters±30%.

6. A system as in claim 1 wherein the housing has rear walls at multiple depths for canceling sound at various different frequencies.

7. A system as in claim 1 wherein the chamber is adjacent to the fluid flow path such that first sound from the external environment enters the chamber, is reflected off of a rear wall of the chamber and cancels other second sound entering the chamber such that the first and second sound do not continue along the fluid flow path, the second sound having a wavelength within 6 cm of the first sound, the rear wall being a distance of within 4 cm of a ¼ of the wavelength of the first and/or second sound from a central area of an opening that provides fluid communication to the passenger compartment.

8. A system as in claim 1 wherein the structure is part of an automotive vehicle.

9. A system as in claim 8 wherein the structure is a pillar of the automotive vehicle.

10. A system for reducing the passage of sound from a first location to a second location, the system comprising:

a structure of an automotive vehicle, the structure having one or more openings for providing fluid communication between an internal cabin of an automotive vehicle and an external environment surrounding the vehicle;

an housing associated with the structure of the automotive vehicle, wherein:

i. the housing substantially surrounds a chamber; and

ii. the housing includes one or more openings for providing fluid communication between the internal cabin of the automotive vehicle and the external environment surrounding the vehicle; and

iii. sound enters the housing through the one or more openings of the housing and is reflected off one or more walls defining the chamber thereby canceling at least a portion of the sound.

11. A system as in claim 10 wherein the housing is formed substantially entirely of plastic.

12. A system as in claim 10 wherein the structure is a pillar of an automotive vehicle.

13. A system as in claim 10 wherein the housing includes a first opening in fluid communication with the chamber and a second opening.

14. A system as in claim 13 wherein the chamber is located beside a path from the first opening to the second opening.

15. A system as in claim 14 wherein the chamber is located closer to a distal end of the housing relative to both the first and second openings.

16. A system as in claim 10 wherein an annular seal extends about a periphery of the housing.

17. A system as in claim 16 wherein the seal is formed of a heat activatable material that foams and cures upon exposure to elevated temperatures.

18. A system for reducing the passage of sound from a first location to a second location, the system comprising:

a structure of an automotive vehicle, the structure having one or more openings for providing fluid communication between an internal cabin of an automotive vehicle and an external environment surrounding the vehicle, wherein the structure of the automotive vehicle is a pillar;

an housing associated with the structure of the automotive vehicle, wherein:

i. the housing substantially surrounds a chamber; and

ii. the housing includes one or more openings for providing fluid communication between the internal cabin of the automotive vehicle and the external environment surrounding the vehicle;

iii. sound enters the housing through the one or more openings of the housing and is reflected off one or more walls defining the chamber thereby canceling at least a portion of the sound; and

iv. the chamber is adjacent to a fluid flow path between the first and second openings such that first sound from the external environment enters the chamber, is reflected off of a rear wall of the chamber and cancels other second sound entering the chamber such that the first and second sound do not continue along the fluid flow path, the second sound having a wavelength within 6 cm of the first sound, the rear wall being a distance of within 4 cm of a ¼ of the wavelength of the first and/or second sound from a central area of an opening that provides fluid communication to the passenger compartment.

19. A system as in claim 18 wherein the housing is substantially entirely formed of plastic.

20. A system as in claim 18 wherein an annular seal extends about a periphery of the housing.