Magnetic Clutch Bidirectional Torque Transmission

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Solution Overview

Problem

Conventional bicycles and exercise devices with freewheel hubs do not efficiently transmit torque in both rotational directions, limiting the user's ability to propel the bicycle backward or adjust resistance during exercise.

Innovation Solution

Incorporating a magnetic clutch into the drivetrain, which connects the drive mechanism to the flywheel, allowing the hub to move between a locked state and an unlocked state based on an electric current, thereby enabling efficient torque transmission in both rotational directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a freewheel hub is used in the drivetrain, then the bicycle can roll forward faster than the user pedals and backpedaling is prevented, but torque transmission in reverse direction is lost and user control is reduced

Engineering Contradiction:

Improveforward rolling speedVSAvoidreverse torque transmission

Core Design Contradiction:

SpeedVSEase of operation

Solution Approach 1:

The magnetic clutch enables dynamic switching between freewheel mode (unlocked) and fixed gear mode (locked). The system transitions from a static unidirectional connection to a dynamically controllable bidirectional connection, allowing the drivetrain to adapt its torque transmission characteristics based on operational requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The magnetic clutch acts as an intermediary component between the drive mechanism and the wheel. It mediates torque transmission by selectively engaging or disengaging the connection, enabling controlled bidirectional torque transmission while maintaining the benefits of unidirectional freewheel operation when needed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If a direct drive drivetrain is used, then torque transmission in both directions is enabled, but the energy requirements from the user increase and training intensity becomes excessively high

Engineering Contradiction:

Improvebidirectional torque transmissionVSAvoiduser energy input

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The system dynamically switches between locked and unlocked states of the magnetic clutch, allowing the user to select between fixed gear mode (bidirectional torque, higher energy input) and freewheel mode (unidirectional torque, lower energy input) based on training requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The magnetic clutch changes the operational parameters of the drivetrain by transitioning between engaged and disengaged states. This parameter change allows the system to adjust torque transmission characteristics and energy requirements to match different exercise intensities and user capabilities.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If a magnetic clutch is added to enable bidirectional torque transmission, then user control and exercise intensity adjustment are improved, but the device complexity increases

Engineering Contradiction:

Improvedrivetrain mode switchingVSAvoiddrivetrain component count

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The magnetic clutch replaces complex mechanical switching mechanisms with an electromagnetic field-based system. Instead of using mechanical linkages, gears, or clutches to achieve mode switching, the invention uses magnetic fields to engage or disengage the torque transmission path, simplifying the overall mechanical complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic clutch serves multiple functions: it enables bidirectional torque transmission when locked, allows freewheel operation when unlocked, and provides a means for user control or automated control of drivetrain mode. This multi-functionality reduces the need for separate components for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 magnetic clutch system allows for seamless transition between freewheel and fixed gear modes, enhancing user control and exercise intensity by ensuring efficient torque transmission in both rotational directions.

Implementation Method 1

The magnetic clutch includes a field coil that is configured to produce a magnetic field upon application of an electric current

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

An armature is rotationally fixed to the flywheel and axially movable along the rotational axis between a locked position and an unlocked position based on a presence of the magnetic field

Methodology Applied

Scientific EffectMagnetic force: Magnetic Field

Data Source

PatentUS12280294B2Magnetic clutch for a pedaled drivetrain

Publication Date: 2025.04.22 IFIT INC

AI summary

A magnetic clutch transitions a drivetrain or flywheel between a freewheel or unlocked mode or configuration and a locked or fixed gear mode or configuration. The magnetic clutch includes a rotor rotationally fixed to the pedals of the drivetrain. An armature is connected to the flywheel. A field coil generates a magnetic field which causes the armature to move to the flywheel. Friction between the armature and the rotor rotationally fixes the flywheel to the rotor.