Bicycle Transmission Shift Mechanism Load Management
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Solution Overview
Problem
Existing bicycle transmissions with shift assist mechanisms face inefficiencies in transmitting manual drive force and managing excessive loads, leading to potential damage and reduced gear shifting performance.
Innovation Solution
The bicycle transmission incorporates a shift mechanism with a power transmission mechanism and a shift assist mechanism, utilizing saver springs and an electric actuator to efficiently transmit rotational force and manage load distribution, allowing for controlled gear shifting and reduced load on the electric actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shift assist mechanism transmits rotational force through both saver springs to the shift control member, then the gear shifting action is assisted, but excessive load is applied to the transmission path from the shift input member to the shift control member when the shift control member cannot rotate due to large drive torque
Solution Approach 1:
The patent introduces an intermediate transmission path through the second saver spring that connects the shift assist mechanism to the shift control member, bypassing the first saver spring. This intermediary path allows rotational force to be transmitted directly to the shift control member without passing through the first saver spring, thereby preventing excessive load accumulation when the shift control member cannot rotate due to large drive torque.
2Device complexity
If the shift input member is directly connected to the shift control member without the shift assist mechanism, then the transmission path is simple, but manual drive force cannot be efficiently transmitted to assist the gear shifting action
Solution Approach 1:
The patent segments the transmission path into two distinct routes: one through the first saver spring for normal operation, and another through the second saver spring for assist operation. This segmentation allows the manual drive force to be efficiently transmitted through the second saver spring path to assist gear shifting, while maintaining a relatively simple overall structure.
3Extent of automation
If the electric actuator is connected to the shift input member, then the shifting action is electrically controllable, but the load on the electric actuator increases when the shift assist mechanism operates
Solution Approach 1:
The second saver spring acts as an intermediary that provides an alternative path for rotational force transmission. When the shift assist mechanism operates, it can transmit force through the second saver spring directly to the shift control member, bypassing the electric actuator connection point at the shift input member. This reduces the load on the electric actuator while maintaining electrical control capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables efficient manual drive force transmission and enhanced gear shifting performance, reducing the risk of excessive load on the transmission components and allowing for precise control of the shifting action.
Implementation Method 1
the shift control member receives the rotational force applied in a first direction about the axle through the first saver spring as the shift input member is rotated in the first direction. In the shift mechanism, the shift control member receives the rotational force applied in a second direction opposite to the first direction through the second saver spring
Data Source
AI summary
A bicycle transmission includes an axle, an input component, a power transmission mechanism, a shift mechanism and an output component. The input component receives manually applied rotational force. The output component is rotatably supported by the axle. The power transmission mechanism transmits the rotational force of the input component to the output component through one of a plurality of power transmission paths. The shift mechanism includes a shift input member, a shift control member, a first saver spring and a second saver spring. The shift input member is settable in a plurality of rotational positions. The shift control member rotates in conjunction with movement of the shift input member to select one of the power transmission paths. In the shift mechanism, as the shift input member rotates in the first direction, the shift control member receives the rotational force applied in a first direction through the first saver spring.