Vibration Energy Harvester Core Assembly for Precise Axial Length

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Solution Overview

Problem

Existing vibration energy harvesters require precise machining operations to achieve accurate axial length of the magnetic core assembly, increasing manufacturing complexity and cost.

Innovation Solution

A magnetic core assembly is manufactured by joining a tubular outer component to two flat inner components, allowing for precise definition of axial length through grinding, reducing the need for complex machining operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single central joint structure with flanges and recesses is used to assemble the magnetic core assembly, then the number of joints is minimized and symmetry is preserved, but two precise machining operations are required increasing manufacturing complexity

Engineering Contradiction:
Improvenumber of jointsVSAvoidmachining precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The magnetic core assembly is divided into three separate components: a first magnetic core part, a second magnetic core part, and a central magnetic core part. This segmentation allows each component to be manufactured independently with simpler machining operations, avoiding the need for complex flange and recess machining required in single-joint designs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The central magnetic core part acts as an intermediary component that connects the first and second magnetic core parts. This intermediary structure provides a straightforward assembly interface that reduces the number of precise machining operations needed compared to direct flange-to-recess joining.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If precise machining operations are performed to achieve accurate axial length, then the axial length is defined accurately, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveaxial length accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By segmenting the magnetic core assembly into multiple parts with defined interfaces, the axial length can be controlled through the cumulative dimensions of simpler components rather than requiring precise machining of a single complex piece.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The magnetic core parts are designed with pre-defined dimensional relationships and interfaces that facilitate accurate axial length assembly through standardized joining operations, eliminating the need for post-assembly precision machining.

Inventive Principle:
Principle #10Preliminary action

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 solution enables a highly accurate axial length with lower manufacturing complexity and cost, enhancing electrical power output and efficiency in converting mechanical vibrational energy into electrical energy.

Implementation Method 1

when the system vibrates, a coil cuts through the flux formed by a magnetic core

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A typical magnet-coil generator consists of a spring-mass combination attached to a magnet or coil

Methodology Applied
Scientific EffectSpring vibration: Spring

Data Source

PatentEP3743988B1An electromechanical generator for converting mechanical vibrational energy into electrical energy
Publication Date: 2026.02.11 HITACHI RAIL LTD
  • EP3743988B1 patent drawingFigure 1
  • EP3743988B1 patent drawingFigure 2~3
  • EP3743988B1 patent drawingFigure 4

AI summary

An electromechanical generator for converting mechanical vibrational energy into electrical energy, the electromechanical generator comprising: a central mast, an electrically conductive coil assembly fixedly mounted to the mast, the coil assembly at least partly surrounding the mast, the coil assembly having radially inner and outer sides and first and second opposite edges, a mount for the coil assembly extending radially inwardly of the radially inner side and fixing the coil assembly to the mast, a magnetic core assembly movably mounted to the mast for linear vibrational motion along an axis about an equilibrium position on the axis, the magnetic core assembly at least partly surrounding the coil assembly and the mast, wherein the magnetic core assembly comprises: an outer core, comprising a one-piece tubular body, which encloses the electrically conductive coil assembly on the radially outer side, first and second end cores magnetically coupled to the outer core at respective first and second ends of the outer core, the first and second end cores extending radially inwardly and enclosing the respective first and second opposite edges of the coil assembly, wherein either (i) both of the first and second end cores are fitted to and contact the outer core at the respective first and second ends of the outer core, or (ii) one of the first and second end cores is fitted to and contacts the outer core at the respective first or second end of the outer core and the other of the first and second end cores is integral with the outer core at the respective first or second end of the outer core, and first and second magnets spaced along the axis, wherein the first and second magnets contact and are magnetically coupled to the respective first and second end cores, and the first and second magnets define therebetween a gap in the magnetic core assembly through which the mount extends.