Reluctance Rotor Mechanical Stabilization via Casting Compound

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional reluctance rotors are unsuitable for high-speed applications, particularly in motor vehicles, due to mechanical instability caused by punched-out sections that act as magnetic flux barriers, leading to reduced mechanical stability and torque yield at speeds above 3,000 revolutions per minute.

Innovation Solution

A reluctance rotor design featuring an intermediate part with recesses and webs between laminated core layers, filled with a non-ferromagnetic casting compound, which enhances mechanical stability and allows for higher speeds by distributing centrifugal forces and providing additional reinforcement, while maintaining high torque output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If punched-out sections are used to form flux barriers in rotor laminations, then magnetic flux barrier function is improved, but mechanical stability deteriorates

Engineering Contradiction:
Improvemagnetic flux barrier functionVSAvoidmechanical stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent uses composite materials by combining ferromagnetic rotor lamination layers with non-ferromagnetic casting compound (aluminum or synthetic resin). The flux barriers are formed by recesses in the rotor laminations that are filled with the casting compound, creating a composite structure that provides both magnetic flux barrier function and mechanical stability through the combination of materials with different properties.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If punched-out sections are used to form flux barriers, then magnetic flux barrier function is improved, but torque yield deteriorates

Engineering Contradiction:
Improvemagnetic flux barrier functionVSAvoidtorque yield
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

The casting compound material is selected to provide both magnetic blocking capability and torque transmission capability. The non-ferromagnetic casting compound (aluminum or synthetic resin) fills the flux barrier recesses and provides mechanical coupling between rotor laminations, enabling the structure to transmit torque effectively while maintaining the magnetic flux barrier function.

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If intermediate part with recesses and webs is added, then mechanical stability is improved, but device complexity increases

Engineering Contradiction:
Improvemechanical stabilityVSAvoidstructural complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the intermediate part: it provides mechanical stabilization through webs, creates additional flux barriers through recesses, and serves as a support structure for the casting compound. The intermediate part combines structural reinforcement with magnetic flux management functions, reducing the need for separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The intermediate part performs multiple functions simultaneously: it reinforces the mechanical stability of the rotor core, creates additional magnetic flux barriers, and provides a structure for casting compound attachment. This multi-functional design reduces overall device complexity by consolidating several functions into a single component.

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

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 design enables the rotor to operate at speeds greater than 5,000 rpm, making it suitable for electric vehicle drives by improving mechanical stability and torque efficiency through the use of a non-ferromagnetic casting compound that transfers centrifugal forces effectively.

Implementation Method 1

When the reluctance rotor rotates as intended, the hardened casting compound transfers centrifugal forces acting from the laminated rotor layers to the intermediate part

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

The punched-out sections result in curved, strip-shaped sheet metal sections that serve as flux-conducting sections and conduct the magnetic flux in the manner required to provide the reluctance of the rotor

Methodology Applied
Scientific EffectMagnetic flux conduction: Magnetic Field

Implementation Method 3

The reactance of the laminated core is in the direction of the q-axis, i. H. the magnetic blocking direction is relatively small due to the non-magnetic areas

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Data Source

PatentEP3103183B1Reluctance rotor with mechanical stabilisation
Publication Date: 2017.11.29 SIEMENS AG
  • EP3103183B1 patent drawingFigure 1
  • EP3103183B1 patent drawingFigure 2
  • EP3103183B1 patent drawingFigure 3

AI summary

The invention relates to a reluctance rotor (10) for an electric machine (E), comprising rotor lamination layers (16) made of a ferromagnetic material, wherein each rotor lamination layer (16) has a flux barrier (22) formed by a recess in the rotor lamination layer (16). The problem addressed by the invention is to toughen the reluctance rotor (10) for a high torque and a high rotational speed. For this purpose, the reluctance rotor (10) has an intermediate part (32) with recesses (36) arranged between a first and a second rotor lamination layer (16), and separators (38) delimiting the recesses (36) from one another. The recesses (36) of the intermediate part (32) and the separators (38) are arranged axially between the flux barriers (22), wherein the recesses (36) of the intermediate part (32) and the flux barriers (22) together delimit a space. This space is cast with a non-ferromagnetic casting compound.