프로니 해석을 이용한 브레이크 MoC 래틀 소음의 신뢰성 시험 방법

Abstract

The research of Noise, Vibration and Harshness (NVH) characteristics has been ongoing for the improved brake systems in the vehicle development field. Especially, brake rattle noise is one of the most important noises to make passengers annoyed and needs to be resolved. However, brake systems are complicated due to enlargement and electrification of them. This paper is introduced to rattle noise of Motor on Caliper (MoC) a combination of conventional brake and Electric Parking Brake (EPB). Moreover, a test method by using a quite shaker to simulate a real vehicle condition is introduced and the rattle noise is analyzed at the occurred condition. Basically, natural frequencies of two different plates are measured and Sound Pressure Level (SPL) and acceleration of time signals are acquired when they are impacted each other. Then both the time signals are analyzed to frequency domain and were considered to be main factors influencing the rattle noise. In conclusion, the limit of existing Fast Fourier Transform (FFT) is mentioned and to estimate dominant frequencies of rattle noise, Prony analysis (Prony’s method) is applied and verified for difference between new and half pad test. Finally, Aging test was conducted to confirm the vulnerable characteristics of MoC rattle noise by using Prony analysis as well.