Bicycle Bottom Bracket Hanger Water Ingress Sealing

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Solution Overview

Problem

Conventional bicycle bottom bracket hangers fail to effectively prevent water ingress from the bicycle frame, leading to potential water intrusion near the bearing assembly, which can cause issues such as bearing damage and maintenance challenges.

Innovation Solution

A bicycle bottom bracket hanger design featuring a tubular hanger part with an inner tubular member and a sealing arrangement, comprising O-ring sealing members, is used to prevent water ingress by creating a sealed interface between the tubular hanger part and the inner tubular member, ensuring water does not reach the bearing assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional bottom bracket hanger without sealing arrangement is used, then the structure is simple and inexpensive, but water can intrude into the tubular hanger part and reach the bearing assembly

Engineering Contradiction:
Improvewater protection capabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a nested structure where an inner tubular member is placed inside the outer tubular hanger part, with sealing members positioned between them. This nested arrangement creates an effective seal against water ingress while maintaining a compact and relatively simple overall structure, resolving the contradiction between water protection capability and structural complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent employs sealing members (such as O-rings or elastomeric seals) that function as flexible sealing elements between the inner and outer tubular members. These flexible sealing components effectively block water intrusion paths without requiring complex rigid structures, thereby improving water protection while keeping the design relatively simple.

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If a sealing arrangement with inner tubular member is added, then water ingress is prevented, but manufacturing cost increases

Engineering Contradiction:
Improvewater protection capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The bottom bracket hanger is segmented into distinct components: an outer tubular hanger part, an inner tubular member, and separate sealing members. This segmentation allows each component to be manufactured independently using standard processes, and the sealing members can be easily installed during assembly, thereby limiting water ingress while controlling manufacturing costs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses relatively simple and inexpensive sealing members (such as rubber O-rings or basic elastomeric seals) that are cost-effective to manufacture and replace. These economical sealing components provide effective water protection without significantly increasing manufacturing costs, resolving the contradiction between reliability and ease of manufacture.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If the sealing arrangement is disposed entirely within the tubular hanger part, then water is contained, but disassembly allows water to escape and wet the bearings

Engineering Contradiction:
Improvewater containment capabilityVSAvoidbearing protection during maintenance
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent positions the sealing arrangement to create a water trap or reservoir within the tubular hanger part that can hold water during normal operation. The design anticipates disassembly scenarios by configuring the sealing arrangement and water drainage features to minimize the risk of water escaping onto bearings during maintenance, balancing water containment with ease of repair.

Inventive Principle:
Principle #9Preliminary anti-action

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

The design effectively limits water ingress into the bottom bracket hanger, reducing the risk of bearing damage and maintenance needs, while being relatively inexpensive to manufacture and maintain.

Implementation Method 1

a sealing arrangement disposed between the tubular hanger part and the inner tubular member

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP1975054B2Bicycle bottom bracket hanger
Publication Date: 2015.07.29 SHIMANO INC
  • EP1975054B2 patent drawingFigure 1~2
  • EP1975054B2 patent drawingFigure 3
  • EP1975054B2 patent drawingFigure 4

AI summary

A bicycle bottom bracket hanger is basically provided with a tubular hanger part 36, an inner tubular member 40 and sealing arrangement. The tubular hanger part 36 includes an interior surface 36a with a first open end 36b and a second open end 36c that is axially spaced from the first open end 36b. The inner tubular member 40 is coaxially disposed in the tubular hanger part 36 between the first and second open ends 36b of the tubular hanger part 36. The sealing arrangement is disposed between the tubular hanger part 36 and the inner tubular member. The sealing arrangement is entirely disposed within the tubular hanger part between the first and second open ends of the tubular hanger part 36.