Magnetic Epicyclic Gear with Variable Torque Control

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Solution Overview

Problem

Magnetic epicyclic gears lack the ability to adjust torque transmission parameters during operation, limiting their use as a variable torque limiter and clutch, and requiring new designs for torque adjustments.

Innovation Solution

A magnetic epicyclic gear design with an inner and outer ring and a middle ring featuring ferromagnetic bars and a controller, allowing for adjustable torque transmission through varying the air gap and magnetic flux, enabling continuous or discrete geometry changes and material property adjustments to adapt to changing conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the magnetic planetary gear uses a fixed design geometry, then the torque transmission is reliable and limited, but the torque parameters cannot be adjusted during operation

Engineering Contradiction:
Improvetorque adjustment capabilityVSAvoidgear geometry complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the air gap between the inner and outer rings adjustable during operation. The air gap can be varied continuously or discretely, allowing the torque transmission characteristics to be dynamically changed without redesigning the entire gear geometry. This enables the magnetic planetary gear to adapt to different torque requirements while maintaining a relatively simple fixed geometric structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the air gap dimension, which is a critical geometric parameter affecting magnetic flux and torque transmission. By changing the air gap parameter during operation, the torque capacity and slip characteristics can be adjusted. This approach allows torque parameter adjustment without fundamentally changing the gear's geometric configuration, thus resolving the contradiction between adaptability and geometric complexity.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the air gap between rings is increased, then the torque transmission is reduced and slip behavior is influenced, but the magnetic flux is changed requiring larger magnets or coils

Engineering Contradiction:
Improvetorque transmission adjustmentVSAvoidmagnetic flux energy consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent uses parameter changes by adjusting the air gap dimension to control torque transmission and slip behavior. When the air gap is increased to reduce torque and enable slip, the system accepts the consequence of reduced magnetic flux. This is a deliberate parameter trade-off where the air gap serves as the primary control variable, and the magnetic flux adjustment is an accepted side effect rather than a separately optimized parameter.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by allowing different sections of the magnetic gear to have different magnetic properties. The inner and outer rings can be equipped with magnets or coils of varying strengths in different regions, enabling localized adjustment of magnetic flux. This allows the system to compensate for air gap variations in specific areas while maintaining overall torque control, thereby managing the energy consumption implications of air gap changes.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the magnetic planetary gear is designed for reliable torque limitation, then it can overspeed or slip to limit torque, but it cannot function as a variable torque converter or coupling

Engineering Contradiction:
Improvefunctional versatilityVSAvoidtorque limitation reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies dynamics by enabling continuous adjustment of the air gap during operation, which transforms the magnetic planetary gear from a fixed-function torque limiter into a variable torque converter and coupling. By dynamically controlling the air gap, the system can operate in different modes: maintaining reliable torque limitation when needed, or enabling smooth torque conversion and coupling by reducing slip. This dynamic control resolves the contradiction by allowing the same device to fulfill multiple functional roles.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements universality by designing the magnetic planetary gear to perform multiple functions through a single adjustable mechanism. The variable air gap control enables the gear to function as a torque limiter, torque converter, and coupling device. This multi-functionality is achieved without adding separate components, as the same geometric adjustment mechanism serves all three functions, thereby increasing adaptability while maintaining reliability.

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

4Reliability

If multiple separate components are used for torque conversion, limitation, and coupling, then each function is optimized, but the overall system complexity and installation space increase

Engineering Contradiction:
Improvefunctional performanceVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies merging by combining torque conversion, torque limitation, and coupling functions into a single magnetic planetary gear unit. The variable air gap mechanism integrates all three functions that would traditionally require separate components. This consolidation reduces the number of parts, simplifies the overall system architecture, and decreases installation space while maintaining the functional performance of each individual function through the unified adjustable design.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables flexible torque adjustment and monitoring, reducing component complexity, cost, and installation space, while protecting components from overloading by implementing a load-sensing and power interruption function.

Implementation Method 1

an inner ring with a first number of magnetic poles, an outer ring with a second number of magnetic poles

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

a middle ring with a number of ferromagnetic rods

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 3

the transmissible torque can be varied by the control system during operation... the air gap between the individual rings can be adjusted... The magnetic flux is changed, thereby influencing the slippage behavior

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Data Source

PatentEP3410588B1Magnetic epicyclic gear with variable torque
Publication Date: 2022.08.31 DEERE & CO
  • EP3410588B1 patent drawingFigure 1~2
  • EP3410588B1 patent drawingFigure 3
  • EP3410588B1 patent drawingFigure 4~5

AI summary

A magnetic transmission is described, comprising an inner ring (18), a middle ring (20) with a number of ferromagnetic rods (24), an outer ring (22) and a control, wherein the middle ring (20) is configured such that the transmissible torque is actively variable during operation.