Nested Bicycle Pinion Assembly for Small Sprocket Mounting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bicycle derailleur systems face challenges in accommodating small sprockets with 10 teeth or less, particularly in sophisticated setups requiring close gear ratios, as conventional designs struggle to mount such sprockets effectively.
Innovation Solution
A multiple pinion arrangement with a first pinion having a larger inner diameter than the mounting body, connected via a flange section, supports smaller secondary pinions cantilevered from it, allowing secure attachment and weight reduction, while a detent projection and groove ensure easy mounting on a receiving body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If small sprockets with 10 teeth or less are used to achieve close gear ratios, then gearing precision is improved, but mounting difficulty increases due to insufficient space on conventional drive units
Solution Approach 1:
The patent implements a nested pinion configuration where a first pinion with larger inner diameter is mounted on the drive unit, and second pinions with smaller inner diameters are mounted on the first pinion. This nesting arrangement allows small sprockets (10 teeth or less) to be accommodated by mounting them on an intermediate pinion rather than directly on the drive unit, thereby achieving close gear ratios while maintaining ease of mounting.
2Adaptability or versatility
If multiple pinions are added to accommodate small sprockets, then gearing versatility is improved, but device complexity increases
Solution Approach 1:
The patent uses a nested pinion arrangement where second pinions are mounted on the first pinion, creating a compact multi-sprocket assembly. This nesting approach provides gearing versatility for different chain paths and ratios while maintaining a relatively simple structure where the pinions are radially supported by the drive unit through a single mounting interface.
Solution Approach 2:
The first pinion serves multiple functions: it acts as a functional pinion for torque transmission and simultaneously serves as a mounting hub for the second pinions. This multi-functionality reduces the need for separate mounting structures, thereby providing gearing versatility without proportionally increasing device complexity.
3Adaptability or versatility
If adapters or additional mounting structures are used to accommodate small pinions, then small sprocket compatibility is improved, but weight increases
Solution Approach 1:
The first pinion is designed to serve dual purposes: as a functional gear element for torque transmission and as a mounting structure for the second pinions. By eliminating the need for separate adapters or additional mounting structures, the design achieves small sprocket compatibility while minimizing weight increase.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A multi-gear assembly (10) for mounting on a rear wheel axle of a bicycle comprises a mounting body (12) designed for mounting on the rear wheel axle and a sprocket assembly (16). The sprocket assembly (16) comprises a first sprocket (18) whose inner diameter is larger than an outer diameter of the mounting body (12) and which is connected to the mounting body (12). Furthermore, the sprocket assembly (16) comprises at least a second sprocket (20, 22) whose inner diameter is smaller than an outer diameter of the mounting body (12) and which is cantilevered and connected to the mounting body (12) via the first sprocket (18) in a torque-transmitting manner.