Pedal force sensing apparatus for an electric bicycle

摘要

A pedal force sensing apparatus includes a pedal force input shaft, a force action sleeve, a torque output shaft, at least one elastomer, a micro optical pickup head module, a diversion sleeve, a linear sliding bush and a displacement sensor. The pedal force input shaft to which an input torque is applied drives the force action sleeve combined with it to simultaneously rotate. Sequentially, the force action sleeve applies forces to the elastomer to have reaction force acting on the torque output shaft. When a reverse torque from the loading of the electric bicycle is applied to the opposite end of the torque output shaft, the rotations of the torque output shaft and the force action sleeve occur, and relative angular displacement between them simultaneously exists. Because the constraint relation exists between the first guiding pin of the force action sleeve and the spiral slot of the diversion sleeve, the first guiding pin has a push force acting on the diversion sleeve along the axial direction. On the other hand, the second guiding pin of the diversion sleeve slides along the leading groove of the torque output shaft, and therefore the relative angular movement does not exist between them. After the axial push forces from the first guiding pin acts on the diversion sleeve, the diversion sleeve has a linear displacement along the axial direction. The diversion sleeve and linear sliding bush only have the conjunction of axial movement, hence the linear sliding bush has the same axial displacement for the displacement sensor to detect the magnitude of the pedal force.