Centre shaft four-speed transmission for bicycle

Abstract

The invention discloses a centre shaft four-speed transmission for a bicycle. A center shaft, a counter shaft and an output shaft are arranged in parallel in a box body which is fixed on a frame; one end of the center shaft is provided with a big gear wheel; at least one groove is formed on the counter shaft along an axial direction; a pinion is arranged at the engagement position of the counter shaft and the big gear wheel; the counter shaft is provided with a gear A, a gear B and a gear C sequentially from one end of the pinion; a front shifting fork is arranged at the fit position of the gear B; the front shifting fork is fixed on a front shaft sleeve, and at least one groove is formed on the output shaft along the axial direction; a gear D is arranged at the engagement position of the output shaft and the pinion; the output shaft is provided with a gear E, a shaft sleeve, a gear F and a gear G sequentially from one end of the gear D; a rear shifting fork is arranged at the fit position of the shaft sleeve; the rear shifting fork is fixed on a rear shaft sleeve; opposite sides of the front shaft sleeve and the rear shaft sleeve are provided with teeth, and the front shaft sleeve and the rear shaft sleeve are fixed on the box body through a front long shaft and a rear long shaft respectively; and the gear which is engaged with the front shaft sleeve and the rear shaft sleeve at the same time is connected with a shifting-up/shifting-down striking wheel and a gear positioning wheel through a short shaft.

Description

technical field [0001] The invention relates to a transmission, in particular to a bicycle center shaft four-speed transmission. Background technique [0002] Bicycle is a convenient, low-carbon, environmentally friendly, and a means of transportation that can strengthen the body. Its structure and shape are constantly changing and improving. However, the "speed" problem has always been a key issue in the improvement of bicycles, whether it is in a flat city or in a rugged country, it should be comfortable and labor-saving. "Speed ​​shifting" has not been greatly improved from the initial increase of the diameter of the active wheel to the shifting of the foreign "mountain bike", which has hindered its development. [0003] The speed change bicycles and mountain bikes currently on the market use one or two driving gears on the central shaft, four or more driven gears, and speed through the combination of a chain and a certain driving to driven gear. The disadvantage of the...

AI Technical Summary

Problems solved by technology

[0003] The speed change bicycles and mountain bikes currently on the market use one or two driving gears on the central shaft, four or more driven gears, and speed through the combination of a chain and a certain driving to driven gear. The disadvantage of the transformation is that the transformation speed is slow, and the friction between a certain group of gears and the chain is serious. Since the driving wheel passes through the chain and the driven wheel is not in a straight line, the meshing wear of the chain and the gears increases the manpower of the rider, and does not feel labor-saving. , but also damage the transmission and chain, causing unnecessary losses

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