汽车前围板隔声量测定及改进

基于混响室-消声室声强测量方法，测量某汽车前围板的隔声量。结果表明：空调进气口内外循环转换阀与阀口贴合不紧密是隔声薄弱主要原因。在与空调进气口内外循环转换阀阀口相贴合的阀体部位粘贴密封材料，用EVA+低熔点毛毡+双组分声学材料代替原有的EVA+低熔点毛毡材料后，相应的测试结果表明：改进后，该汽车前围板的隔声量在500～6300 Hz频段平均提高了约7 dB。对改善其隔声性能进而改善车内声学环境具有重要意义。

Measurement of Transmission Loss and Improvement of Structure of a Car’s Dash Panel

The transmission loss of a car dash panel was measured based on reverberation room-anechoic room method with sound intensity. Results show that the change-over valve for the inside cycle and the outside cycle in the air inlet of the air conditioner is the primary acoustic weak link because its poor fit with the valve port. On this basis, some sealing material was pasted on some parts of the change-over valve, where the valve body touches the valve port. Besides, the original acoustic material, EVA + Low Melting Point Felt, was replaced by a modified one, EVA + Low Melting Point Felt+ Bi-component. Corresponding measurement results show that the transmission loss of the car dash panel is improved by about 7dB on average in 500~6300Hz. This work is of great significance on the improvement of the sound insulation property of the dash panel and the acoustic environment in the car.