Exterior silencer for motor vehicle

1. An exterior noise silencer for a motor vehicle to be arranged on a portion of a vehicle compartment of the motor vehicle, the exterior noise silencer comprising:

a sound-absorbing layer made of a sound-absorbing material;

a shape-retaining layer formed by binding fibers made of an inorganic material with a binder resin, said shape-retaining layer being laminated on said sound-absorbing layer;

a front skin layer made of a thermoplastic synthetic resin material and laminated on said shape-retaining layer; and

an aeration-suppressing layer laminated between said shape-retaining layer and said front skin layer,

wherein said aeration-suppressing layer is formed with nonwoven fabric so as to have a basis weight within a predetermined basis weight range and an airflow quantity within a predetermined airflow quantity range which are suitable for suppressing oozing of said binder resin from said shape-retaining layer upon being molded so as to be formed into a laminated body by heating and pressing together with said sound-absorbing layer, said shape-retaining layer and said front skin layer.

2. The exterior noise silencer for a motor vehicle according to claim 1 , wherein:

said shape-retaining layer is a first shape-retaining layer; and

the exterior noise silencer further comprises:

a second shape-retaining layer formed by binding fibers made of an inorganic material with a binder resin, said second shape-retaining layer being laminated on said sound-absorbing layer from the side opposite to said first shape-retaining layer; and

a non-air permeable film layer laminated on said second shape-retaining layer so as to oppose said sound-absorbing layer through said second shape-retaining layer.

3. The exterior noise silencer for a motor vehicle according to claim 1 , wherein:

said shape-retaining layer is a first shape-retaining layer; and

the exterior noise silencer further comprises:

a second shape-retaining layer formed by binding fibers made of an inorganic material with a binder resin, said second shape-retaining layer being laminated on said sound-absorbing layer from the side opposite to said first shape-retaining layer; and

a back skin layer made of nonwoven fabric so as to be laminated on said second shape-retaining layer opposing said sound-absorbing layer through said second shape-retaining layer.

4. The exterior noise silencer for a motor vehicle according to claim 3 , further comprising a non-air permeable film layer laminated between said second shape-retaining layer and said back skin layer.

5. The exterior noise silencer for a motor vehicle according to claim 2 , wherein:

said fibers for forming said first shape-retaining layer are glass fibers, and

the sound-absorbing material as a material for forming said sound-absorbing layer is a urethane resin.

6. The exterior noise silencer for a motor vehicle according to claim 3 , wherein:

said fibers for forming said first shape-retaining layer are glass fibers, and

the sound-absorbing material as a material for forming said sound-absorbing layer is a urethane resin.

7. The exterior noise silencer for a motor vehicle according to claim 4 , wherein:

said fibers for forming said first shape-retaining layer are glass fibers, and

the sound-absorbing material as a material for forming said sound-absorbing layer is a urethane resin.

8. The exterior noise silencer for a motor vehicle according to claim 2 , wherein:

said fibers for forming said second shape-retaining layer are glass fibers, and

the sound-absorbing material as a material for forming said sound-absorbing layer is a urethane resin.

9. The exterior noise silencer for a motor vehicle according to claim 3 , wherein:

said fibers for forming said second shape-retaining layer are glass fibers, and

the sound-absorbing material as a material for forming said sound-absorbing layer is a urethane resin.

10. The exterior noise silencer for a motor vehicle according to claim 4 , wherein:

said fibers for forming said second shape-retaining layer are glass fibers, and

the sound-absorbing material as a material for forming said sound-absorbing layer is a urethane resin.

11. The exterior noise silencer for a motor vehicle according to claim 5 , wherein:

the predetermined basis weight range of said aeration-suppressing layer is in a range of 10 (g/m 2 ) to 40 (g/m 2 ) and the predetermined airflow quantity range of said aeration-suppressing layer is in a range of 15 (cc/s/cm 2 ) to 65 (cc/s/cm 2 ),

said front skin layer has a basis weight within a range of 50 (g/m 2 ) to 160 (g/m 2 ), and

said first shape-retaining layer has a basis weight within a range of 25 (g/m 2 ) to 130 (g/m 2 ) and an airflow quantity within a range of 200 (cc/s/cm 2 ) to 800 (cc/s/cm 2 ).

12. The exterior noise silencer for a motor vehicle according to claim 6 , wherein:

the predetermined basis weight range of said aeration-suppressing layer is in a range of 10 (g/m 2 ) to 40 (g/m 2 ) and the predetermined airflow quantity range of said aeration-suppressing layer is in a range of 15 (cc/s/cm 2 ) to 65 (cc/s/cm 2 ),

said front skin layer has a basis weight within a range of 50 (g/m 2 ) to 160 (g/m 2 ), and

said first shape-retaining layer has a basis weight within a range of 25 (g/m 2 ) to 130 (g/m 2 ) and an airflow quantity within a range of 200 (cc/s/cm 2 ) to 800 (cc/s/cm 2 ).

13. The exterior noise silencer for a motor vehicle according to claim 2 , the portion of the vehicle compartment being a hood which is capable of opening and closing an upper opening portion of an engine room of the motor vehicle,

wherein the exterior noise silencer is assembled to the hood from an inside of the engine room as a hood silencer.

14. The exterior noise silencer for a motor vehicle according to claim 3 , the portion of the vehicle compartment being a hood which is capable of opening and closing an upper opening portion of an engine room of the motor vehicle,

wherein the exterior noise silencer is assembled to the hood from an inside of the engine room as a hood silencer.

15. The exterior noise silencer for a motor vehicle according to claim 4 , the portion of the vehicle compartment being a hood which is capable of opening and closing an upper opening portion of an engine room of the motor vehicle,

wherein the exterior noise silencer is assembled to the hood from an inside of the engine room as a hood silencer.

16. The exterior noise silencer for a motor vehicle according to claim 5 , the portion of the vehicle compartment being a hood which is capable of opening and closing an upper opening portion of an engine room of the motor vehicle,

wherein the exterior noise silencer is assembled to the hood from an inside of the engine room as a hood silencer.

17. The exterior noise silencer for a motor vehicle according to claim 6 , the portion of the vehicle compartment being a hood which is capable of opening and closing an upper opening portion of an engine room of the motor vehicle,

wherein the exterior noise silencer is assembled to the hood from an inside of the engine room as a hood silencer.

18. The exterior noise silencer for a motor vehicle according to claim 8 , the portion of the vehicle compartment being a hood which is capable of opening and closing an upper opening portion of an engine room of the motor vehicle,

wherein the exterior noise silencer is assembled to the hood from an inside of the engine room as a hood silencer.

19. The exterior noise silencer for a motor vehicle according to claim 10 , the portion of the vehicle compartment being a hood which is capable of opening and closing an upper opening portion of an engine room of the motor vehicle,

wherein the exterior noise silencer is assembled to the hood from an inside of the engine room as a hood silencer.

20. The exterior noise silencer for a motor vehicle according to claim 11 , the portion of the vehicle compartment being a hood which is capable of opening and closing an upper opening portion of an engine room of the motor vehicle,

wherein the exterior noise silencer is assembled to the hood from an inside of the engine room as a hood silencer.