| 摘要 |
PROBLEM TO BE SOLVED: To provide a road surface condition detection apparatus which constantly detects a road surface condition by using tire cavity resonance. SOLUTION: A box 2 made from a metallic plank or a die casting and having a natural frequency of 500 to 1,000 Hz is placed on a vehicle floor 3. A microphone 1 as sound pressure detection means which detects sound is placed in a closed space formed within the box 2. A processor 5 connected to the microphone 1 through a connecting cable 4 detects two, high and low peak frequencies F_low and F_high and sound pressure levels P_low and P_high corresponding to F_low and F_high, respectively, from cavity resonance by a tire detected by the microphone 1. The processor 5 determines (detects) the condition of a road surface on which a vehicle is travelling from the detected sound pressure levels and the frequency difference between the two, high and low peak frequencies. COPYRIGHT: (C)2005,JPO&NCIPI
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