Bicycle Built-in Motor Torque Sensor Elastic Body Integration

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Solution Overview

Problem

Existing built-in motors for electric bicycles have a complicated structure and low accuracy in measuring pedaling force due to their torque sensing systems.

Innovation Solution

A built-in motor design featuring a motor housing with a planetary gear mechanism, an elastic body connected to a torque sensor, and a second planetary gear mechanism for deceleration, which allows accurate pedaling force measurement without the need for wireless power supply and transmission, simplifying the structure and reducing energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a torque sensing system is disposed in the electric powered bicycle to measure pedaling force, then the motor can be controlled according to riding situation, but the structure becomes complicated and measurement accuracy decreases

Engineering Contradiction:
Improveautomatic power adjustmentVSAvoidstructure complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent combines the torque sensing function with the existing planetary gear mechanism by integrating a torque sensor into the elastic body that is already part of the gear system. The ring gear, elastic body, and torque sensor are merged into a single integrated assembly, eliminating the need for separate torque sensing components and reducing overall structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The elastic body serves multiple functions: it acts as both a mechanical element in the planetary gear mechanism and as a mounting structure for the torque sensor. This multi-functional design allows the same component to contribute to both power transmission and torque measurement, reducing the total number of parts needed.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Extent of automation

If a torque sensing system is disposed in the electric powered bicycle to measure pedaling force, then the motor can be controlled according to riding situation, but the measurement accuracy of pedaling force is low

Engineering Contradiction:
Improveautomatic power adjustmentVSAvoidpedaling force measurement accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The elastic body serves as an intermediary element between the ring gear and the torque sensor. It transmits the torque from the gear mechanism to the sensor while providing a stable mounting surface, ensuring accurate torque measurement through this intermediate structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The torque sensing function is segmented from the general power transmission system and placed specifically at the ring gear location. By positioning the torque sensor at this specific point in the gear mechanism, the system achieves accurate local measurement that can be used for overall power control.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If wireless power supply and transmission are used for the torque sensor, then the structure can be simplified, but energy consumption increases

Engineering Contradiction:
Improvestructural simplicityVSAvoidenergy consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent replaces wireless power and data transmission with traditional wired connections. The torque sensor is connected to the control system through physical wiring, eliminating the need for wireless communication components and reducing energy consumption while maintaining acceptable structural complexity.

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

The design achieves accurate pedaling force measurement, simplifies the structural complexity, and reduces energy consumption and production costs, enabling efficient coordination of manpower and motor output for enhanced performance.

Implementation Method 1

a ring gear of the first planetary gear mechanism is connected with an elastic body, and the elastic body is fixedly mounted in the inner stator frame; a torque sensor is disposed on the elastic body, and the torque sensor can be configured to detect a pedaling force

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3480102B1Built-in motor for bicycle and electric powered bicycle
Publication Date: 2021.01.20 WUHAN TTIUM MOTOR TECH CO LTD
  • EP3480102B1 patent drawingFigure 1
  • EP3480102B1 patent drawingFigure 2
  • EP3480102B1 patent drawingFigure 3

AI summary

A built-in motor for a bicycle and an electric powered bicycle, which relate to the technical field of electric powered bicycle, and address the technical problems in the prior art of the complex structure and low measurement accuracy of torque sensors in built-in bicycle motors. The built-in motor for the bicycle comprises: a motor shell (011), a motor inner stator (012) fixed in the motor shell (011) by means of an inner stator frame; a motor outer rotor (013) is installed on the inner stator frame, the motor outer rotor (013) and a motor body output shaft (014) being connected into a whole; a first planetary gear mechanism (015) arranged in the inner stator frame, and the first planetary gear mechanism (015) being used for increasing input human force before outputting the same; an outer gear ring of the first planetary gear mechanism (015) is connected with an elastic body (031), the elastic body (031) being fixedly arranged in the inner stator frame; a torque sensor (032) is arranged on the elastic body (031), the torque sensor (032) being used for measuring the pedaling force provided by a rider to the bicycle .