Investigating The Factors Affecting Cabin Comfort for Agricultural Machinery

Customer expectations for cabin tractors from comfort perspective has grown multifold in the recent years. Cabin noise and vibration is one of the crucial parameter which drives comfort feel for the customer. This would enable customer to remain comfortable during long working hours. Moreover, Cabin Tractors with lesser noise levels found to have better acceptance by Customers all over the world. The Nebraska reports studied for US based tractor shows evolution of trend of cabin noise in 100-150hp tractors in last couple of decades. Undoubtedly, tractor manufacturers have put lot of efforts towards meeting legislation demand & stringent customer requirements for European and US market. This paper presents the work carried out for investigating major contributing factors affecting tractor cabin Noise & Vibration for an existing 75HP tractor. Virtual and experimental studies have been carried out to identify the principal source of noise and the transfer paths for cabin noise distinguishing contribution of airborne and structure borne noise through commercially available software's. Parameters like overall noise levels, noise transfer functions, dynamic stiffness of brackets are correlated with test data. Virtual validation has helped to identify critical paths and contribution of each path. Modification of acoustic material suggested by optimizing the thickness, material properties to arrive at best combination Cabin structure is optimized to reduce structure borne contribution by identifying critical area through simulation. Cabin mount plays major role in customer comfort from tactile vibration perspective. Tactile vibration at customer touch point were predicted and correlated with test data. Cabin mount stiffness was optimized to eliminate abnormal vibration at tactile location. All simulation suggested modifications were implemented and successfully validated through test assessment. Moreover, the core findings of this research paper are compiled as part of NVH contenting strategy and being used as design guidelines for future projects.