Noise insulating wall structure
AssigneeNissan Motor Co., Ltd.
InventorsYasuyuki Asahara, Keijiro Iwao
Life of this patent
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Abstract
A noise insulating wall structure includes tubular extensions which extend into a space defined between spaced insulating plates. The extensions formed on the lower of the two plates are formed with openings which allow water, which accidentally finds its way into the interior of the panel, to drain out and thus not effect the sound attenuating performance of panel. The drain openings have an area which is determined based on a ratio of the area of the opening to the total circumferential area (including the area of the opening) of the extension.
Claims19
A noise insulating wall structure comprising:
- two spaced noise insulating plates which define a space therebetween;
- a plurality of holes penetratingly provided in said noise insulating plates so as to face each other in pairs;
- a first number of the pairs of holes being communicated with one another by a corresponding number of straight tubes, and
- a second number of the pairs of holes each having an extension wall portion extending into the space and toward an opposite noise insulating plate;
- an opening formed in a selected extension wall portion to communicate the space with one of the plurality of holes to drain water from the space;
- and
- wherein x exists within the range which is satisfied by the following expression:
- ##EQU5## wherein:
- x is the shortest distance between said opening and a surface of a nearest noise insulating plate;
- f is a frequency of the noise to be attenuated;
- c is the speed of sound;
- .alpha. is an opening ratio of the area of said opening to the area of the noise insulating wall;
- .beta. is a ratio of the area of the first number of holes communicated by the cylinder portion to a total area of the holes;
- t is a thickness of the noise insulating plates;
- h is a length of the extension wall portions;
- a is a radius of the holes associated with the extension wall portions;
- .delta. is a compensated value at an edge of the holes;
- and
- d is a distance between the noise insulating plates.
A noise insulating wall structure interposed between a first space which is exposed to a sound source and a second space which is shielded from the sound source, the wall structure comprising:
- a first sound-shielding wall (29a) facing the first space;
- a second sound-shielding wall (29b) facing the second space;
- a sound-shielding space (42) defined between the first and second spaces;
- a tube element (39) which extends through the sound-shielding space (42), the tube element having a first end (35a) which is open to the first space and a second end (35b) which is open to the second space;
- a first pipe element (43) having a base end (37a) which is open to the first space and a free end (43a) which opens into the sound-shielding space (43);
- a second pipe element (43) having a base end (37b) which is open to the second space and a free end (43a) which is open to the sound-shielding space (42), the free end (43a) of the second pipe element (43) being located opposite to the free end (43a) of the first pipe element (43);
- and
- opening means (45, 53, 61, 69), provided through a pipe wall (41) of one of the first and second pipe elements (43), for controlling a sound-shielding frequency-characteristic of the wall body (27);
- and wherein:
- the second pipe element (43) comprises a tubular cylindrical body (43) projecting from a predetermined region of the second sound-shielding wall (29b);
- and
- the opening means defines an opening (45, 53, 61, 69) in a side wall (41) of the tubular cylindrical body (43) for shielding sounds in a frequency range defined such that ##EQU6## where:
- f is a frequency of the sounds to be shielded;
- c is a sound speed;
- x is a distance between the opening and the predetermined region;
- .alpha. is an opening proportion of the wall body;
- .beta. is an opening ratio of the tube element to the wall body;
- t is a thickness in the predetermined region of the second sound-shielding wall;
- h is a projection length of the tubular cylindrical body;
- a is an inside diameter of the tubular cylindrical body;
- .delta. is a compensation factor;
- and
- d is a distance between the predetermined region and the first sound-shielding wall.
Dependencies are inferred from the claim text.