Bicycle Hub Shift Positioner for Accurate Gear Alignment
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Solution Overview
Problem
Existing internal transmission hub assemblies for bicycles face challenges in achieving consistent and accurate shifting due to improper alignment of elements, requiring precise adjustments of the lever actuating shifting mechanism.
Innovation Solution
A multi-speed internal bicycle hub transmission assembly with a shift control mechanism that includes a positioner to ensure correct orientation of elements, allowing for reliable and accurate shifting between power transmission paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If positioning is accomplished solely by the lever actuating shifting mechanism and cable, then the structure remains simple, but alignment accuracy deteriorates requiring minute adjustments
Solution Approach 1:
The positioning function is segmented into two independent parts: the lever actuating shifting mechanism for coarse positioning and the internal positioning mechanism (positioner with indexing member and spring) for fine alignment. This segmentation allows each component to specialize in its positioning range, achieving high overall accuracy without requiring the entire system to be complex.
Solution Approach 2:
The internal positioning mechanism acts as an intermediary between the cable actuation and the final element alignment. The positioner with its indexing member and spring provides an intermediate positioning stage that refines the alignment after the lever mechanism establishes the basic position, eliminating the need for minute adjustments of the lever.
2Ease of operation
If the lever actuating shifting mechanism is not set to exactly the correct position, then element alignment fails, but adjusting the lever requires minute movements reducing ease of operation
Solution Approach 1:
The internal positioning mechanism is self-service in nature, automatically adjusting and maintaining precise element alignment without requiring the operator to make minute lever adjustments. The spring-loaded positioner with indexing member self-regulates to keep elements properly aligned throughout operation, eliminating the need for continuous operator intervention to maintain precision.
Solution Approach 2:
The internal positioning mechanism performs preliminary alignment of elements before the lever actuating mechanism completes the shifting action. By pre-positioning the elements in the correct alignment, the system ensures that when the lever moves to the next position, alignment is already established, making the shifting operation easier and more reliable.
Data Source
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AI summary
A multi-speed internal bicycle hub transmission assembly (12) includes a hub axle (24), a driver (25), a hub shell (26), a power transmission mechanism (14) and a shift control mechanism (16). The driver (25) and the hub shell (26) are rotatably supported to the hub axle (24). The power transmission mechanism (14) is disposed between the driver (25) and the hub shell (26) for transmitting rotational power from the driver (25) to the hub shell (26). The shift control mechanism (16) includes a shift controller (18) and a positioner (22). The shift controller (18) is movable in rotational directions relative to the hub axle (24) to a plurality of orientations. Each orientation of the shift controller (18) corresponds to selection of a corresponding one of plurality of power transmission paths of the power transmission mechanism (14). The positioner (22) is non-movable in the rotational direction relative to the hub axle (24) and is biased into contact with the shift controller (18).