Bicycle Sprocket Support Assembly with Integrated Radial Members

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Solution Overview

Problem

Conventional bicycle hubs have sprocket carriers that are heavy and lack rigidity, leading to inefficiencies in weight distribution and positional accuracy of sprocket teeth.

Innovation Solution

A bicycle sprocket support assembly featuring a tubular sprocket support body with integrated radial sprocket support members that securely fasten sprockets, eliminating the need for heavy spider arms and splined portions, enhancing rigidity and positional accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If conventional sprocket carriers with splined portions are used, then sprockets can be mounted on the carrier, but the carrier becomes heavy and lacks rigidity

Engineering Contradiction:

Improvesprocket carrier weightVSAvoidsprocket carrier rigidity

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The sprocket carrier is divided into multiple individual sprocket support members that are separately mounted on the drive body, rather than using a single monolithic carrier. This segmentation allows each support member to be optimized for its specific function, reducing overall weight while maintaining rigidity where needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a traditional radial mounting approach to an axial mounting approach for the sprockets. By mounting sprockets on the axial side of the drive body rather than radially, the design eliminates the need for heavy splined portions while maintaining secure attachment and rigidity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If conventional sprocket carriers are used, then sprockets can be supported, but the positional accuracy of sprocket teeth deteriorates due to backlash

Engineering Contradiction:

Improvesprocket teeth positional accuracyVSAvoidsprocket carrier structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the splined portion from the drive body, which was the source of backlash and positional inaccuracy. By removing this intermediate splined interface, the sprockets are mounted directly on the drive body in a simpler manner that eliminates backlash while maintaining manufacturing precision.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of mounting sprockets radially on the drive body as in conventional designs, the invention inverts the mounting approach by positioning sprockets on the axial side of the drive body. This inversion eliminates the need for splined portions and reduces backlash, improving positional accuracy of sprocket teeth.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS9193416B2Bicycle sprocket support assembly

Publication Date: 2015.11.24 SHIMANO INC

AI summary

A bicycle sprocket support assembly is provided with a sprocket support body, a first sprocket support member and at least first and second sprockets. The sprocket support body has a tubular shaped part with an exterior surface and an interior surface arranged around a center longitudinal axis. The first sprocket support member is integrated with the exterior surface of the sprocket support body as a one-piece, unitary member and projects radially from the exterior surface of the sprocket support body. The first and second sprockets are fixed to the first sprocket support member by at least one fastener with the first and second sprockets being supported at axially spaced apart locations along the center longitudinal axis of the sprocket support body.