조향시스템의 랙-피니언(Rack&Pinion) 래틀(Rattle)소음 저감에 관한 연구

This paper addresses a modification for reducing rattle noise of an CEPS(Column type Electric Power Steering) system. To simulate rattle noise of the steering system, analytical test rig including rack bar, pinion shaft, tie rods, support yoke assembly and rack housing for rack and pinion system and motor, worm wheel and worm gear for reduction system is made with ADAMS. Then, vehicle test is carried out for input data like left/right side forces, left/right vertical accelerations and handle angle to the analytical model. Analytical results and vehicle test results show a good relationship. Based on the analytical model, to reduce rattle noise of rack and pinion part, a cam-type yoke system that has a self-adjusting function is added to the analytical model. The modified system shows a good rattle performance in vehicle test as well as the analytical model.