Bicycle Rear Derailleur Base Member Segmentation

Solution Overview

Problem

The manufacturing of bicycle rear derailleurs is complex and costly due to the need for forging and machining of metal parts for battery retention, which complicates the process and increases costs.

Innovation Solution

The design shifts battery retention features from the forged metal portion to an injection molded plastic portion, simplifying the manufacturing process and reducing costs by eliminating the need for complex metal machining at the battery interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If battery retention features are integrated into the forged metal base member, then the structural strength is maintained, but the manufacturing complexity and cost increase due to complex forging and machining operations

Engineering Contradiction:

Improvestructural strengthVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The base member is divided into two separate portions: a forged metal portion providing structural strength and an injection-molded plastic portion containing the battery retention features. This segmentation allows each portion to be manufactured using the most appropriate process for its function, reducing overall manufacturing complexity while maintaining structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base member uses a composite structure combining metal and plastic materials. The metal portion provides the necessary structural strength, while the plastic portion provides the battery retention features. This composite approach allows each material to be used where it is most effective, simplifying the manufacturing process for each component.

Inventive Principle:

Principle #40Composite materials

2Strength

If battery retention features are integrated into the forged metal base member, then the structural strength is maintained, but the manufacturing cost increases due to complex forging and machining operations

Engineering Contradiction:

Improvestructural strengthVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The base member is divided into two separate portions: a forged metal portion providing structural strength and an injection-molded plastic portion containing the battery retention features. This segmentation allows each portion to be manufactured using the most appropriate process for its function, reducing overall manufacturing complexity while maintaining structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base member uses a composite structure combining metal and plastic materials. The metal portion provides the necessary structural strength, while the plastic portion provides the battery retention features. This composite approach allows each material to be used where it is most effective, simplifying the manufacturing process for each component.

Inventive Principle:

Principle #40Composite materials

3Strength

If battery retention features are integrated into the forged metal base member, then the structural strength is maintained, but the tolerance loop increases due to multiple manufacturing steps

Engineering Contradiction:

Improvestructural strengthVSAvoidtolerance loop

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The base member is divided into two separate portions: a forged metal portion providing structural strength and an injection-molded plastic portion containing the battery retention features. This segmentation allows each portion to be manufactured using the most appropriate process for its function, reducing overall manufacturing complexity while maintaining structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The injection-molded plastic portion acts as an intermediary that interfaces between the battery and the metal base member. This intermediary absorbs some of the tolerance requirements, reducing the tolerance loop in the metal portion and simplifying the overall manufacturing precision requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10894574B2Bicycle rear derailleur

Publication Date: 2021.01.19 SRAM LLC

AI summary

A bicycle rear derailleur includes a base member having a first portion and a second portion. The first portion of the base member is mountable to a bicycle frame, and the second portion of the base member is attached to the first portion of the base member and includes at least a portion of a power supply attachment. The bicycle rear derailleur also includes a movable member movably coupled to the first portion of the base member and electrically connected to the second portion of the base member. The bicycle rear derailleur includes a chain guide assembly rotatably connected to the movable member.