输送机链传动链轮
conveyor chain drive sprocket
摇动节无声链
rocker joint silent chain
电动传声器
moving-conductor microphone
moving-coil microphone
dynamic microphone
抗噪声传声器
antinoise microphone
noise-cancelling microphone
闭式差动传动机构
closed pattern of transmission mechanism
步进链传动
intermittent roller chain drive
差动传动
differential transmission