Experimental Analysis of Rattle Noise Abatement in Seatbelt Retractor Assembly

Squeak & rattle issues for an automobile interior component design have rapidly increased due to customer's expectations for high quality vehicles. Also, due to advances in the reduction of vehicle interior and exterior noise, safety restraints have recently been brought to the forefront to meet the vehicle interior sound quality. When the retractor is subjected to a higher level of vibration input and is located close to the driver's or passenger's ears, the retractor is prone to rattle and the rattle noise is detectable subjectively. The objective of this paper is to experimentally analyze the seatbelt retractor rattle noise and to evaluate various rattle noise abatement methodologies through a design of experiment matrix. A test methodology specified in the vibration noise specification for the seatbelt retractor assembly demonstrates the promising attempt to correlate the in-vehicle noise evaluation. A gage study and system capability analysis of the complete noise test system was conducted, and a design of experiment (DOE) of numerous design variables for the rattle noise abatement was studied. Both objective analysis through various sound measurement matrices and subjective jury evaluation through a sound quality system were correlated in order to quantify the level of improvement on the rattle phenomena.