Clatter and rattle noise is an increasing challenge for the development of low-noise transmissions. Efforts to reduce fuel consumption and exhaust emissions of combustion engines combined with a decrease in the idle speed cause increasing cyclic irregularities within modern drivelines which result in increasing clatter and rattle noise. This noise radiation is subject to excited idle components, for example idle gears, which oscillate within their functional clearances due to inhomogeneous speed patterns and therefore impacting against the fixed gears. Numerous external and internal measures for the reduction of clatter and rattle noise propensity have been developed; however only a few were applied to series products. In order to face a constantly enforcing goal conflict between rising irregular rotational movements of combustion engines and known means of noise reduction up to now, new grounds were broken at the Institute of Machine Components. Thus, the method of decoupling is a new measure for an almost complete suppress. All gears that are not in the power flow are shiftable decoupled from their shafts. An outstanding constellation arises for coaxial transmissions with counter shaft. By using only one additional synchronizer pack, the counter shaft can be switched off both in idle mode and direct gear. Thereby, a complete rattle and clatter noise freedom in idle mode and direct gear can be demonstrably achieved, depending on the idler gear arrangement of the transmission. Another benefit of economical interest appears in particular for commercial vehicles. The transmission loss torque decreases significantly which leads to an improvement of the transmission efficiency. On the basis of a patented solution (CARF-transmission) the clatter and rattle noise free transmission is presented in the paper as well as derived developments.
Development process of clatter and rattle noise free (CARF-) Transmissions
Entwicklungsprozess eines klapper- und rasselgeräuschfreien (CARF-) Fahrzeugantriebs
2005
9 Seiten, 13 Bilder, 14 Quellen
Aufsatz (Konferenz)
Englisch
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