DIAMETER CONTROL SPEED CHANGE DEVICE, METHOD AND BICYCLE FOR DIAMETER CONTROL SPEED CHANGE USING THE SAME

摘要

Disclosed are a diameter control speed change device and a diameter control speed change method and a bicycle using the same. The diameter control speed change device according to the present invention, which changes the speed of a gear of a bicycle, comprises: an input part which is located around a handlebar of the bicycle to receive a speed change step of the gear from a user; a control part which controls a speed change part by calculating the diameters of a front wheel chain ring and a rear wheel chain ring of the bicycle corresponding to the speed change step provided from the input part; and the speed change part which changes the diameter of the front and rear wheel chain rings of the bicycle according to the command of the control part.