| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic absorbent which exerts an acoustic absorption effect even in a limited space in an engine cover.SOLUTION: An acoustic absorbent comprises a louver 23 which is slantly attached to an internal face of an engine cover 21 so as to cover projection faces of a plurality of ventilation holes 22, ... which are formed at the engine cover 21 of a movable crane, and acoustic absorption materials 24, 25 being the acoustic absorption materials 24, 25 which are arranged at the louver 23, attached to an entire face of the louver 23, become maximum in thicknesses in positions approximate to the ventilation holes 22, ..., and are reduced in thicknesses as separating from the ventilation holes 22, .... The acoustic absorption materials 24, 25 are constituted of at least the first acoustic absorption material 24 which is arranged while approximating the ventilation holes 22, ..., and relatively thick in thicknesses, and the second acoustic absorption material 25 which is arranged while separating from the ventilation holes ..., and relatively thin in thicknesses.SELECTED DRAWING: Figure 3 |
