Bicycle rear derailleur

Abstract

A bicycle rear derailleur comprises a derailleur rack, a transmission unit, a drive unit and a buffer unit. The transmission unit comprises a bicycle frame holder, an internal linkage part and an external linkage part; the internal linkage part and the external linkage part are in pivot joint with the derailleur rack and the bicycle frame holder. The drive unit is provided with a motor casing which is in pivot joint with the bicycle frame holder and the external linkage part. The buffer unit is in pivot joint with an outer barrel, an inner barrel holder, an inner barrel and an elastic part; the outer barrel is connected with with the external linkage part, the inner barrel holder is in pivot joint with the motor casing and the external linkage, the inner barrel is arranged in the outer barrel and connected with the inner barrel holder, and the elastic part is arranged in the inner barrel. Two ends of the elastic part are respectively connected with a first movable pin and a second movable pin which are capable of slidably running through the inner barrel and the outer barrel respectively; thus, the buffer unit has effect in position switching of the derailleur rack while protecting the drive unit.

Description

technical field [0001] The invention relates to bicycles, in particular to a rear derailleur for a bicycle. Background technique [0002] The rear derailleur of the bicycle is used to guide the chain to one of the chainrings of the rear sprocket. Since each chainring of the rear sprocket has a different size, the bicycle can pass between the chain and different chainrings. Engage to achieve the effect of shifting gears. [0003] In order to prevent the rear derailleur from being damaged by external force collisions, there is a shock absorber design in the prior art. For example, the Chinese Taiwan TWI343643 patent case reduces the impact on the device through the compression deformation of the coil spring, but the position of the coil spring is Mounted on a threaded drive shaft and exposed to the outside, it is bound to be affected by dust, rain or other environmental factors and shorten the service life. In addition, such as the Taiwan TW201231347 patent case of China, th...

AI Technical Summary

Problems solved by technology

[0003] In order to prevent the rear derailleur from being damaged by external force collisions, shock absorbers have been designed in the prior art. For example, the Chinese Taiwan TWI343643 patent case reduces the impact on the device through the compression deformation of the coil spring, but the position of the coil spring is Mounted on a threaded drive shaft and exposed to the outside, it is bound to be affected by dust, rain or other environmental factors and shorten the service life

In addition, such as the Taiwan TW201231347 patent case of China, the main purpose is to arrange balls and preload springs in the nut so that the drive shaft will not cause deformation of the actuating kinematics mechanism when rotating. However, in this existing patent case, in addition to the complex structure In addition to the problem of the nut, the structural configuration of the nut will be limited by the space, which will increase the difficulty of processing, so there is a need for improvement

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