실험적 방법에 의한 모운 노이즈 발생 메커니즘 규명 및 FE 해석에 의한 검증

Abstract

모운 노이즈는 Brake 작동 시 Brake pad와 Disk 사이의 불균형 마찰에 의해 발생하는 비정상 소음으로서 승객에게 불쾌감과 불안감을 유발시킨다. Brake와 Disk사이의 마찰력에 기인하여 모운 노이즈가 발생하며, 제동계의 가진력은 Brake pad와 Caliper, Extra Bracket을 통하여 Coupled Torsion Beam Axle(CTBA)로 전달된다. 본 연구에서는 실차 주행시험을 통해 모운 노이즈를 재현하였고, 모달 테스트를 통하여 모운 노이즈 성분을 가지고 있는 CTBA Module 부품을 규명하였다. 그리고 제동계의 가진력과 CTBA Module의 공진이 모운 노이즈 발생의 주요 원인임을 규명하였다. CTBA Module의 진동과 차실 내 소음의 관계를 규명하기 위하여 전달경로 해석과 기여도 해석을 실시하였다. 기여도 해석에서는Brake pad, Caliper, Spindle Bracket, Trailing arm, V-Beam의 진동 가속도를 입력으로 선정하였고, 모운 노이즈가 발생 할 때 운전석 귀 높이의 소음을 출력으로 선정하여 모운 노이즈를 발생시키는데 기여도가 큰 부품을 규명하였다. 실차 조건에서 CTBA Module의 모드해석 결과와 실차 경계조건을 고려한 Finite Element(FE) 모드 해석 결과의 주파수 응답이 잘 일치하였다. 또한 제동계의 가진력 전달 메커니즘을 이용하여 CTBA Module의 응답특성을 규명 하였다. CTBA Module의 고유 Mode에서 Modal Strain Energy를 계산하여 변형률이 크게 발생하는 위치를 알았으며, 설계 변경을 통하여 모운 노이즈 저감을 위한 개선방향을 제시하였다.|Moan noise occurred by unbalanced friction between brake pad and disk. The noise is inducing uncomfortable. Moan noise is caused friction force between brake and disk, excitation force of brake system is transferred to coupled torsion beam axle through brake pad, caliper and extra bracket. In this study, moan noise is reproduced by driving test of vehicle, components of CTBA module are investigated in moan noise characteristics by modal testing. The resonance between excitation force of brake system and CTBA module is main cause of moan noise. We are performed to transfer path analysis and contribution analysis for investigating relationship between vibrations of CTBA module and interior noise in vehicle. Contribution analysis is used for investigating contribution of each components. The inputs are selected acceleration of vibration at brake pad, caliper, spindle bracket, trailing arm, V-beam and output is selected interior noise at driver seat . The responses between experimental result in full car condition and finite element result in considering boundary condition were coincidence. Also response characteristic of CTBA module is investigated by using transfer mechanism of excitation force of brake system. Calculated modal strain energy at natural frequency of CTBA module is used to grasping position where strain energy occurred largely. And the improve design was presented for reduction of moan noise by changing design; Moan noise occurred by unbalanced friction between brake pad and disk. The noise is inducing uncomfortable. Moan noise is caused friction force between brake and disk, excitation force of brake system is transferred to coupled torsion beam axle through brake pad, caliper and extra bracket. In this study, moan noise is reproduced by driving test of vehicle, components of CTBA module are investigated in moan noise characteristics by modal testing. The resonance between excitation force of brake system and CTBA module is main cause of moan noise. We are performed to transfer path analysis and contribution analysis for investigating relationship between vibrations of CTBA module and interior noise in vehicle. Contribution analysis is used for investigating contribution of each components. The inputs are selected acceleration of vibration at brake pad, caliper, spindle bracket, trailing arm, V-beam and output is selected interior noise at driver seat . The responses between experimental result in full car condition and finite element result in considering boundary condition were coincidence. Also response characteristic of CTBA module is investigated by using transfer mechanism of excitation force of brake system. Calculated modal strain energy at natural frequency of CTBA module is used to grasping position where strain energy occurred largely. And the improve design was presented for reduction of moan noise by changing design