Bicycle Rear Hub Torque Measurement via Opposed Part Gap

Solution Overview

Problem

The existing rear bicycle hubs face challenges in accurately measuring driving force due to the direct adhesion of strain gauges, which complicates the assembly process and affects measurement accuracy.

Innovation Solution

The design incorporates a system where the driving force is measured by detecting the gap between opposed parts using sensors, allowing for accurate detection of torque transfer without the interference of sensor attachment and simplifying assembly, with options for various sensor types and configurations to enhance accuracy and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If strain gauges are affixed directly to the coupling part, then driving force can be measured, but assembly accuracy becomes difficult and measurement precision deteriorates

Engineering Contradiction:

Improvedriving force measurement accuracyVSAvoidassembly accuracy

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediary measurement structure consisting of first and second opposed parts with a gap between them. Instead of directly affixing strain gauges to the coupling part, the sensor detects the gap distance between the two opposed parts. This intermediary approach eliminates the need for direct adhesive application on the coupling part, thereby resolving the contradiction between measurement precision and assembly accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the direct mechanical adhesion method (strain gauge affixed with adhesive) with a non-contact or minimal-contact sensing method. The sensor detects the gap between opposed parts, substituting the mechanical bonding process and eliminating adhesive uniformity requirements, thus improving both assembly accuracy and measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If strain gauges are affixed directly to the coupling part, then driving force can be measured, but assembly process becomes complicated

Engineering Contradiction:

Improvedriving force measurement accuracyVSAvoidassembly ease

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent introduces an intermediary measurement structure consisting of first and second opposed parts with a gap between them. Instead of directly affixing strain gauges to the coupling part, the sensor detects the gap distance between the two opposed parts. This intermediary approach eliminates the need for direct adhesive application on the coupling part, thereby resolving the contradiction between measurement precision and assembly accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the direct mechanical adhesion method (strain gauge affixed with adhesive) with a non-contact or minimal-contact sensing method. The sensor detects the gap between opposed parts, substituting the mechanical bonding process and eliminating adhesive uniformity requirements, thus improving both assembly accuracy and measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This approach enables precise measurement of driving force while simplifying the assembly process and improving measurement accuracy by using sensors to detect the gap between opposed parts, reducing noise and weight, and allowing for flexible sensor placement and type selection.

Implementation Method 1

The driving force measuring part includes at least one sensor arranged to measure at least one of the gap between the first and second opposed parts and a displacement of the gap

Methodology Applied

Scientific EffectGap detection:

Data Source

PatentUS9221517B2Bicycle rear hub

Publication Date: 2015.12.29 SHIMANO INC

AI summary

A bicycle rear hub includes a hub spindle, a drive part, a hub shell, at least one first opposed part, at least one second opposed part and a driving force measuring part. The drive part is rotatably supported on the hub spindle, and configured to receive a driving-force-input member. The hub shell is rotatably supported on the hub spindle and operatively coupled to the drive part for rotation by the drive part on the hub spindle. The at least one first opposed part is coupled to the drive part. The at least one second opposed part is coupled to the hub shell and being disposed oppose to the first opposed part with a gap therebetween. The driving force measuring part includes at least one sensor arranged to measure at least one of the gap between the first and second opposed parts and a displacement of the gap.