美国麻省理工学院的一位工程师发明了一种新的自行车传动装置,用较小的蹬力就产生10种速度的出力。在这种新型传动系统中,对于给定负荷来说,凸轮的形状决定了脚蹬用力的大小,并可以按骑车人体力情况更换适当的凸轮。此传动装置由一对凸轮和一对能脉动地驱动自行车后轮的拉杆组成,能在每个脉动之间形成 An engineer at the Massachusetts Institute of Technology invented a new bicycle transmission that produces 10 speeds with less effort. In this new drivetrain, the shape of the cam determines the amount of pedal effort for a given load, and the appropriate cam can be replaced according to the rider’s physical condition. The transmission consists of a pair of cams and a pair of pulleys that pulsate the rear wheels of the bicycle and can be formed between each pulsation