Claw-Pole Generator Magnet Clamping

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Solution Overview

Problem

In claw-pole generators for motor vehicles, the permanent magnets and holding elements experience forces due to vibrational stress and acceleration, requiring secure fixation to prevent magnetic leakage flux and enhance power output, but existing solutions fail to effectively secure these elements under such conditions.

Innovation Solution

The introduction of clamping projections on the holding elements and grooves, which can be elastic or rigid, allows for secure axial or circumferential clamping of permanent magnets between poles, using designs such as spring tongues or radial webs to ensure stable positioning and bonding with additional resin for enhanced retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If holding elements are pushed into holding grooves to secure permanent magnets, then assembly is simplified, but the holding elements cannot withstand vibrational stress and acceleration forces

Engineering Contradiction:
Improveassembly simplicityVSAvoidsecuring under vibration and acceleration
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The holding element incorporates an elastic clamping projection that can dynamically deform under load. During assembly, the elastic projection is compressed to allow insertion into the holding groove. Once assembled, the projection elastically recovers to exert continuous clamping force on the permanent magnet, securing it against vibrational stress and acceleration forces while maintaining the simple push-in assembly process

Inventive Principle:
Principle #15Dynamics

2Power

If permanent magnets are arranged between poles to reduce magnetic leakage flux, then power output increases, but the magnets become loose under operational forces

Engineering Contradiction:
Improvepower outputVSAvoidmagnet positioning stability
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The holding element uses a clamping projection that extends in a direction perpendicular to the main insertion axis. This radial or circumferential clamping dimension provides additional securing capability beyond the simple axial insertion, creating a multi-dimensional fixation that prevents the permanent magnet from becoming loose under operational forces while maintaining its position for optimal magnetic flux

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If holding elements are designed with clamping projections to secure magnets, then retention under vibration improves, but assembly complexity increases

Engineering Contradiction:
Improveretention under vibrational stressVSAvoidholding element structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The holding element's clamping projection is designed with elastic properties, changing the mechanical parameter from rigid to flexible. This elasticity allows the projection to automatically adjust its clamping force based on the assembly conditions and operational loads, providing reliable retention under vibrational stress without requiring complex adjustment mechanisms or multiple components

Inventive Principle:
Principle #35Parameter changes

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

This solution effectively secures permanent magnets between poles, reducing magnetic leakage flux and increasing power output by providing a robust and reliable fixation mechanism that withstands vibrational stress and acceleration, thereby enhancing the performance of claw-pole generators.

Implementation Method 1

the holding element and/or the holding groove are designed to be elastic or have an elastic part

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a permanent magnet for reducing magnetic leakage flux being arranged between at least two adjacent poles

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP2174402B1Electrical machine
Publication Date: 2017.05.10 ROBERT BOSCH GMBH
  • EP2174402B1 patent drawingFigure 1~2
  • EP2174402B1 patent drawingFigure 3~5
  • EP2174402B1 patent drawingFigure 6~7

AI summary

The invention relates to an electrical machine, in particular a claw-pole machine for a motor vehicle, having a stator or rotor which has a plurality of poles which can be energized electrically, wherein a permanent magnet is arranged between at least two adjacent poles of the poles, which are alternately magnetically polarized in the circumferential direction, in order to reduce any stray magnetic force, and this permanent magnet is held by means of a holding element between the adjacent poles, wherein the holding element is located in holding grooves, which are arranged opposite one another, in the poles. The invention provides for the holding element (2) and/or at least one of the holding grooves (8, 10) to have at least one clamping projection (14).