| 摘要 |
<p>An elongate air duct 4 for mounting on the cab 1 of a truck as part of an air intake assembly 8 comprising of moulded plastics material and has a first air intake end and a second air outlet end. In section transverse to its length, the duct is formed by opposed widthwise walls (17, 18 Figs. 4a-d) and by opposed end walls (20, 21). The opposed widthwise walls are of greater length as seen in said section than the end walls. Along its length, the duct has at least one first region (14, 16 Fig. 3) in which the interior of the duct is transversely sub-divided by two laterally spaced first partitions (31, 33) each of which defines with the adjacent end wall of the duct and intervening portions of the widthwise walls respective first tube formations (10 Fig. 3) extending along the duct. Each first tube formation is formed by a moulded portion of a said widthwise wall that extends inwardly of the duct to contact the opposed widthwise wall. The duct of the present application provides a rigid structure to reduce the noise due to vibration at certain engine revs.</p> |
