Ram intake unit having a sound absorbing structure

1. A ram intake unit mounted on a front portion of a frame structure of a motorcycle, comprising:

an acoustic material disposed along an inner wall of a ram air intake duct, forming an induction system for a motorcycle combustion engine, for absorbing induction noises; and

a holder for securing the acoustic material to the ram air intake duct, the holder being of a netted configuration and disposed inwardly of the acoustic material,

in which the acoustic material bites or cuts into meshes of the netted holder to allow an inner surface of the holder to be flush with an inner surface of the acoustic material to provide a combined smoothed continuous inner surface.

2. The ram intake unit as claimed in claim 1 , in which the acoustic material and the holder are accommodated within a recess defined in an inner surface of the ram air intake duct and are then regulated in their position in a direction longitudinally thereof.

3. The ram intake unit as claimed in claim 1 , in which an engagement member provided in the ram air intake duct is engaged with an engagement area, provided in the holder, to thereby regulate the position of the holder relative to the ram air intake duct in a direction circumferentially thereof.

4. The ram intake unit as claimed in claim 1 , in which the acoustic material is made of an urethane sponge.

5. The ram intake unit as claimed in claim 1 , in which the holder is of a split type molded products comprised of upper and lower mold segments.

6. The ram intake unit as claimed in claim 1 , in which the ram air intake duct is of a split type molded products comprised of upper and lower mold segments.

7. The ram intake unit as claimed in claim 6 , in which each of the acoustic material and the holder includes two parts fitted to the respective mold segments of the ram intake unit.

8. The ram intake unit as claimed in claim 1 , further comprising a stay for supporting a side viewing mirror and a bracket for supporting a gauge unit, and in which the ram air intake duct, the stay and the bracket are integrally formed by a synthetic resin molding.

9. The ram intake unit as claimed in claim 8 further comprising a headlamp support molded integrally for supporting a headlamp assembly.

10. The ram intake unit as claimed in claim 8 , further comprising a resonator chamber formed integrally for reducing induction noises.

11. The ram intake unit as claimed in claim 1 , in which the acoustic material is made of a flexible material and firmly fixed to the ram air intake duct while having been sandwiched between the holder and the ram air intake duct.

12. A ram intake unit mounted on a front portion of a frame structure of a motorcycle, the ram intake unit comprising:

an acoustic material disposed along an inner wall of a ram air intake duct, forming an induction system for a motorcycle combustion engine, for absorbing induction noises;

a holder for securing the acoustic material to the ram air intake duct;

a stay for supporting a side viewing mirror; and

a bracket for supporting a gauge unit,

in which the ram air intake duct, the stay and the bracket are integrally formed by a synthetic resin molding,

in which the bracket has a gauge mounting surface oriented diagonally rearwardly and the stay has a mirror mounting surface positioned laterally of the meter mounting surface and oriented diagonally forwards and in which a region ranging from the gauge mounting surface of the bracket to the mirror mounting surface of the stay is connected by a flat and continuous wall.

13. The ram intake unit as claimed in claim 12 , in which the gauge mounting surface of the bracket represents a sector shape when viewed from top.

14. A ram intake unit mounted on a front portion of a frame structure of a motorcycle, the ram intake unit comprising:

an acoustic material disposed along an inner wall of a ram air intake duct, forming an induction system for a motorcycle combustion engine, for absorbing induction noises;

a holder for securing the acoustic material to the ram air intake duct;

a stay for supporting a side viewing mirror; and

a bracket for supporting a gauge unit,

in which the ram air intake duct, the stay and the bracket are integrally formed by a synthetic resin molding,

in which the bracket has a rear surface provided with reinforcement rib.

15. A ram intake unit mounted on a front portion of a frame structure of a motorcycle, the ram intake unit comprising:

an acoustic material disposed along an inner wall of a ram air intake duct, forming an induction system for a motorcycle combustion engine, for absorbing induction noises;

a holder for securing the acoustic material to the ram air intake duct;

a stay for supporting a side viewing mirror;

a bracket for supporting a gauge unit, and

a hook for securing a harness to be connected with the gauge, in which the ram air intake duct, the stay, the bracket and the hook are integrally formed by a synthetic resin molding.

16. A ram intake mounted on a front portion of a frame structure of a motorcycle, comprising:

an acoustic material disposed along an inner wall of a ram air intake duct, forming an induction system for a motorcycle combustion engine, for absorbing induction noises; and

a holder for securing the acoustic material to the ram air intake duct, the holder being of a netted configuration and disposed inwardly of the acoustic material,

in which the acoustic material bites or cuts into meshes of the netted holder to allow an inner surface of the holder to be flush with an inner surface of the acoustic material to provide a combined smoothed continuous inner surface, wherein

the meshes of the holder are delimited by a plurality of ribs each having inner and outer surfaces, the inner surface having opposite end edges each representing a sharp corner and the outer surface having opposite end edges, each representing a rounded corner.