Self-Powered Rotary Encoder Using a Magnetic Leaf Spring

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Solution Overview

Problem

Conventional rotary encoders fail to reliably record the movements and positions of a rotating shaft during power outages due to the reliance on batteries or generators, which have limited lifespan and require maintenance.

Innovation Solution

A self-powered rotary encoder with a coil housing and a magnetically conductive leaf spring that generates voltage pulses through relative movement with respect to a magnetic field, utilizing a quasi-modular design with a coil housing and a cavity for the leaf spring, allowing for simple assembly and adaptation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If batteries are used for power supply in rotary encoders, then the device can operate during power outages, but the lifespan is limited and maintenance is required

Engineering Contradiction:
Improveoperation during power outageVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The rotary encoder generates its own operating voltage through electromagnetic induction during rotation, eliminating the need for external power supply or batteries. The measuring element acts as a generator, converting mechanical motion into electrical energy to power the evaluation electronics, thus achieving self-sufficiency and unlimited service life

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the chemical energy storage system (batteries) with an electromagnetic energy conversion system. Instead of storing chemical energy that depletes over time, the system converts mechanical motion into electrical energy through electromagnetic induction, providing continuous operation without maintenance

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

2Reliability

If generators with electronic components are used for power supply, then the device can operate during power outages, but the structure becomes more complex and costly

Engineering Contradiction:
Improveoperation during power outageVSAvoidstructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the measuring element with the power generation function. The same magnetic field and moving component that enable position detection also generate the operating voltage through electromagnetic induction, eliminating the need for separate generator components and voltage converters

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The measuring element serves dual functions: it detects the position and movement of the rotating shaft while simultaneously generating the electrical energy needed to power the evaluation electronics. This multi-functionality simplifies the overall device structure and reduces component count

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

3Measurement precision

If scanning units with power supply are used, then measurement data can be recorded, but the device fails to record data during power outages

Engineering Contradiction:
Improverecording functionalityVSAvoidoperation during power outage
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The evaluation electronics are powered by the voltage generated during shaft rotation itself. As long as the shaft rotates, the measuring element generates sufficient voltage to power the electronics and record measurement data, ensuring continuous operation during power outages without external power supply

Inventive Principle:
Principle #25Self-service

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 energy-autonomous signal generation independent of the power supply, enhancing system stability and reducing maintenance needs by providing a cost-effective and robust solution for detecting shaft movements and positions.

Implementation Method 1

a voltage pulse is generated in at least one coil by at least one magnetic field which executes a relative movement to the coil and acts on the latter

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a leaf spring consisting of magnetically conductive material executes a sudden back and forth movement under the influence of the magnetic field

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Data Source

PatentEP4220094B1Device for detecting movements and/or positions of a magnetic object
Publication Date: 2025.06.25 BAUMER GERMANY GMBH & CO KG
  • EP4220094B1 patent drawingFigure 1~2
  • EP4220094B1 patent drawingFigure 3~5

AI summary

The present invention relates to a device for detecting movements and/or positions of a rotating shaft, in which, depending on the movements and/or positions of the shaft, a voltage pulse is generated in at least one coil (1) by at least one magnetic field which performs a relative movement to and acts upon the coil, wherein the coil has a coil housing (4) which consists of a first housing part (5) and a second housing part (5), the housing parts of the coil being held together by a coil wire (3) and forming a cavity (10) inside, in which a leaf spring (2) made of magnetically conductive material performs a sudden back-and-forth movement under the influence of the magnetic field, wherein a first region of the leaf spring is movably arranged in the cavity, and a second region of the leaf spring is fixed between the first housing part and the second housing part.