以下摘自wikipedia

Most currently-produced passenger cars with petrol or diesel engines use transmissions with 5–8 forward gear ratios and one reverse gear ratio. Electric vehicles typically use a single-speed or two-speed transmission.
The simplest transmissions used a fixed ratio to provide either a gear reduction or increase in speed, sometimes in conjunction with a change in the orientation of the output shaft. Examples of such transmissions are used in helicopters and wind turbines. In the case of a wind turbine, the first stage of the gearbox is usually a planetary gear, to minimize the size while withstanding the high torque inputs from the turbine

【 在 linyixiao 的大作中提到: 】
: 人家有正经的名字减速箱，非要叫变速箱，还要硬解释一下。
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FROM 114.254.1.*