Trapezoidal Stator Magnets for Variable Diameter Motor Starters

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Solution Overview

Problem

Existing stator designs for motor vehicle starters face challenges in achieving precise and reliable assembly of magnets on cylinder heads with variable diameters, leading to potential magnetic leaks and inadequate magnetic contact.

Innovation Solution

The stator incorporates a plurality of permanent trapezoidal magnets arranged in a staggered, contiguous manner with inclined lateral edges relative to the cylinder head's longitudinal axis, allowing for adjustable axial positioning and diameter adaptation, along with retaining lugs and non-magnetic inserts for secure fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnets are pressed against a cylinder head with variable diameter, then magnetic contact is improved, but assembly precision deteriorates due to diameter deviations

Engineering Contradiction:
Improvemagnetic contactVSAvoidassembly precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The magnet geometry is changed from a standard rectangular shape to a trapezoidal shape with an inclined lateral edge. This parameter change allows the magnet to adapt to different cylinder head diameters while maintaining precise assembly, as the inclined edge can accommodate diameter variations without compromising assembly precision or magnetic contact reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The magnet is designed with an asymmetric trapezoidal shape featuring an inclined lateral edge rather than symmetric rectangular sides. This asymmetry enables the magnet to fit against variable diameter cylinder heads, as the inclined edge can compensate for diameter deviations while maintaining reliable magnetic contact and precise assembly positioning.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If the cylinder head diameter varies, then adaptability deteriorates, but magnetic contact must be maintained

Engineering Contradiction:
Improvemagnetic contactVSAvoidadaptability to diameter variations
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The magnet geometry is changed from a standard rectangular shape to a trapezoidal shape with an inclined lateral edge. This parameter change allows the magnet to adapt to different cylinder head diameters while maintaining precise assembly, as the inclined edge can accommodate diameter variations without compromising assembly precision or magnetic contact reliability.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If magnets are arranged contiguously in a staggered manner, then magnetic field distribution is improved, but device complexity increases

Engineering Contradiction:
Improvemagnetic field distributionVSAvoidmagnet arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The magnetic structure is segmented into multiple individual trapezoidal magnets arranged in a staggered pattern around the cylinder head. This segmentation allows for improved magnetic field distribution and better adaptation to variable diameters, as each magnet can be independently positioned and angled to optimize the overall magnetic field configuration.

Inventive Principle:
Principle #1Segmentation

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 configuration ensures a secure and adaptive magnetic contact, reducing magnetic leaks and enabling reliable assembly on cylinder heads with varying diameters, enhancing the overall performance and efficiency of the motor vehicle starter.

Implementation Method 1

stator for a rotating electrical machine, in particular with direct current, this machine being in particular a motor vehicle starter

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a plurality of permanent magnets, in particular of trapezoidal shape, arranged in a staggered manner, in particular in a contiguous manner

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP2173019B1Stator of an electric rotating machine
Publication Date: 2011.02.02 VALEO EQUIP ELECTRIC MOTEUR
  • EP2173019B1 patent drawingFigure 1
  • EP2173019B1 patent drawingFigure 2~3
  • EP2173019B1 patent drawingFigure 4

AI summary

The stator (3) has a yoke (4) comprising a cylindrical wall (41) having a longitudinal axis (X). A trapezoidal shaped permanent magnet (40) is arranged inside the yoke. The magnet has a lateral edge (42) forming an angle with the longitudinal axis of the wall of the yoke, where the angle is less than 5 degrees. A fixation element i.e. slit crown (45), fixes the magnet against an inner surface of the cylindrical wall of the yoke. The fixation element is constituted of a retaining tab (47) that is formed by cutting and folding a metal sheet.