中文摘要：

针对某型车在发动机怠速且开空调冷却风扇高速运转时方向盘会产生振动的问题,找出方向盘怠速振动的主要原因.运用锤击法,测量整车状态下方向盘的固有频率,对于主要的激励源冷却风扇,采用扫频法,测量冷却风扇的固有频率.分析得出怠速方向盘振动是由于冷却风扇固有频率与冷却风扇激励耦合产生共振导致的.在保证冷却性能和成本因素的前提下,采用提升冷却风扇固有频率和锁定冷却风扇最高转速的改进方案,取得了良好效果.

英文摘要：

When the engine of a car is idling with the air conditioner is on and cooling fan is operating at a high speed, the steering wheel of the car vibrates greatly. The main reason of steering wheel vibration in the idling condition was found. Using hammering method, the natural frequency of the steering wheel vibration was measured. By means of scanning frequency experiment, the natural frequency of the cooling fan was measured. It was found that the cause of the steering wheel vibration in the idling condition was the resonance due to the coupling of the natural frequency and the excitation frequency of the cooling fan. Then, an improvement scheme of increasing the natural frequency and controlling the maximum speed of the cooling fan was proposed. Results of the test indicate that the improvement scheme is efficient.