Bicycle Bottom Bracket Assembly Press-Fit Installation

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Solution Overview

Problem

Conventional bicycle bottom bracket assemblies are difficult to install into the hanger part of a bicycle frame, often requiring complex screwing or press-fitting processes that can be cumbersome and prone to misalignment.

Innovation Solution

A bicycle bottom bracket assembly that utilizes a press-fit connection with identical support members and bearing units, where the crank axle is rotatably supported within the tubular hanger part, and the crank arms are secured using splines and bolts, allowing for easy installation and adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional screwing or press-fitting processes are used to install the bottom bracket assembly, then the structural integrity and secure mounting are improved, but the installation complexity and difficulty increase

Engineering Contradiction:
Improvesecure mountingVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the left and right support members into a single integrated bottom bracket assembly that is installed as one unit into the hanger part. This merging eliminates the need for separate screwing or press-fitting operations for each side, reducing installation complexity while maintaining secure mounting through the unified press-fit connection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bottom bracket assembly is pre-configured with bearings and crank axle components assembled before installation. The support members are prepared with precise dimensions and surface finishes in advance, allowing for a straightforward press-fit installation without requiring complex alignment or adjustment procedures during the installation process.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If conventional screwing processes are used to install the bottom bracket assembly, then the secure mounting is improved, but the installation time and labor requirements increase

Engineering Contradiction:
Improvesecure mountingVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The integration of both support members into a single assembly allows for one-time press-fit installation rather than separate screwing operations, significantly reducing installation time while maintaining the secure mounting required for bottom bracket functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the traditional screwing mechanism with a press-fit connection system. This substitution eliminates the need for threaded fasteners and screwing operations, reducing installation time and labor requirements while providing adequate secure mounting through the interference fit between the support members and hanger part.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If conventional press-fitting processes are used for each support member separately, then the secure mounting is improved, but the misalignment risk and installation difficulty increase

Engineering Contradiction:
Improvesecure mountingVSAvoidalignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

By combining both support members into a single integrated assembly with a unified press-fit interface, the patent eliminates the alignment issues that arise from installing separate components. The single press-fit operation ensures automatic centering and precise alignment, reducing the risk of misalignment while maintaining secure mounting.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated bottom bracket assembly acts as an intermediary component that mediates between the hanger part and the crank axle. This intermediate structure provides a pre-aligned platform that ensures precise positioning of the crank axle and bearings, eliminating alignment errors that would occur with separate installations.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution simplifies the installation process by relying on frictional fit and compression, ensuring secure and precise mounting of the crank axle and arms, enhancing ease of assembly and reducing the risk of misalignment while maintaining structural integrity.

Implementation Method 1

The solution simplifies the installation process by relying on frictional fit and compression

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The solution simplifies the installation process by relying on frictional fit and compression

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

a first bearing unit and a second bearing unit that are identical to each other and are press-fitted into the first support member and the second support member, respectively. The first and second bearing units support the crank axle

Methodology Applied
Scientific EffectBall bearing: Ball Bearing

Data Source

PatentEP2557030B1Bicycle bottom bracket assembly
Publication Date: 2014.04.16 SHIMANO INC
  • EP2557030B1 patent drawingFigure 1
  • EP2557030B1 patent drawingFigure 2
  • EP2557030B1 patent drawingFigure 3

AI summary

A bicycle bottom bracket assembly is at least provided with a first support member and a first bearing unit. The first support member includes a first hanger mounting part and a first bearing mounting part. The first bearing unit is coupled to the first bearing mounting part. The first hanger mounting part has a first outer circumferential surface that is configured and arranged to be press-fitted into a first open end of a hanger part of a bicycle frame. The first hanger mounting part has a first slit extending in an axial direction relative to a rotational axis of the first bearing unit from an open axial innermost end of the first slit at least up to a region that is located radially outwardly from the first bearing unit in a radial direction relative to the rotational axis of the first bearing unit.