Brake Coil Wave Winding Layout to Cut Stray Fields

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Solution Overview

Problem

Existing electromagnetically actuable brakes with brake coils face challenges in manufacturing complexity and cost, as well as issues with circulating currents and stray fields due to coil arrangements.

Innovation Solution

The brake coil design features a rotor shaft that can rotate relative to the brake coil, with coil sections arranged in a circumferential direction having different winding senses and radial spacings that are a periodic function of the circumferential angle, allowing for easy manufacturing and minimizing circulating currents through direct connections between adjacent coils, thereby reducing stray fields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional brake coil arrangements are used, then the brake can generate magnetic field, but the manufacturing complexity and cost increase due to direction reversals for each partial coil

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcoil winding complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

Instead of reversing the winding direction for each partial coil as in traditional designs, the patent inverts the approach by maintaining a consistent winding direction and using wave windings with periodically fluctuating radial distances. This inversion of the winding strategy eliminates the need for complex direction reversals while achieving the same magnetic field generation effect

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces dynamic characteristics to the wave windings by allowing the radial distance to fluctuate periodically along the circumferential direction. This dynamic radial positioning of winding wires enables the creation of multiple partial coils with a single continuous winding process, simplifying manufacturing while maintaining electromagnetic performance

Inventive Principle:
Principle #15Dynamics

2Power

If multiple partial coils are arranged in the circumferential direction, then the magnetic field generation is improved, but circulating currents and stray fields increase

Engineering Contradiction:
Improvemagnetic field generationVSAvoidcirculating currents and stray fields
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful circulating currents and stray fields by carefully designing the connection scheme between adjacent partial coils. By ensuring direct connections without overlapping winding sides and by positioning windings in different axial regions, the design removes the sources of these harmful electromagnetic effects while preserving the beneficial magnetic field generation

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local quality by arranging different types of partial coils (with different winding senses) in specific circumferential positions. This localized arrangement ensures that adjacent coils with opposite winding senses are positioned to cancel each other's stray fields, while direct connections between coils eliminate circulating currents in specific regions

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If wave windings with periodic radial spacing are used, then winding density increases, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvewinding densityVSAvoidradial positioning precision
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent employs periodic action by designing wave windings with regularly repeating patterns of radial distance fluctuations. This periodic structure allows for standardized manufacturing processes where the same winding pattern can be repeated around the circumference, reducing the need for high precision in each individual section while maintaining overall winding density

Inventive Principle:
Principle #19Periodic 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

This design simplifies the manufacturing process, reduces production costs, and eliminates circulating currents, resulting in a more efficient and cost-effective brake coil with enhanced magnetic field generation and higher winding density.

Implementation Method 1

a brake coil (12) which has a plurality of partial coils (1.1 to 1.6; 2.1 to 2.6; 3.1 to 3.6)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2844887B1Electromagnetically actuatable brake with a brake coil
Publication Date: 2021.03.10 SEW EURODRIVE GMBH & CO KG
  • EP2844887B1 patent drawingFigure 1
  • EP2844887B1 patent drawingFigure 2
  • EP2844887B1 patent drawingFigure 3

AI summary

The invention relates to an electromagnetically actuatable brake with a brake coil, wherein • the brake coil has a brake rotor shaft which is arranged in a rotatable manner relative to the brake coil, in particular the brake rotor shaft axis is coaxial to the axis of symmetry of the brake coil, i.e. the brake coil axis, • the brake coil has multiple sub-coils (1, 2, 40, 50), in particular the sub-coils (1, 2, 40, 50) are arranged one behind the other in the circumferential direction about the brake coil axis, in particular the sub-coils (1, 2, 40, 50) are arranged in a circular manner about the brake coil axis, • the sub-coils (1, 2, 40, 50) are arranged one behind the other in the circumferential direction and each sub-coil has a different winding direction from the respective neighboring sub-coil (1, 2, 40, 50) in the circumferential direction such that the sub-coils (1, 2, 40, 50) with a first winding direction form a first type and the sub-coils (1, 2, 40, 50) with the opposite winding direction form a second type, • the sub-coils (1, 2, 40, 50) are formed by at least one first wave winding and a second wave winding, and • each of the two wave windings is positioned in a circular manner in the circumferential direction, wherein the radial distance between each of the two wave windings is a periodic function of the circumferential angle.