Rotor Lamination Overhang Hole for Higher Reluctance Torque

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Solution Overview

Problem

Existing rotor laminations for electrical machines, particularly in automotive applications, do not effectively enhance the performance by increasing reluctance torque, leading to inefficiencies in operation.

Innovation Solution

A rotor lamination design featuring a first hole in the first overhang section to form a flux barrier through magnetic saturation, enhancing reluctance torque and compensating for any reduction in generated torque, thereby improving operational efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If holes are provided in the pole head section for cooling purposes, then cooling performance is improved, but reluctance torque is reduced

Engineering Contradiction:
Improvecooling performanceVSAvoidreluctance torque
Core Design Contradiction:
TemperatureVSPower

Solution Approach 1:

The patent applies local quality by differentiating the functional characteristics of different regions within the pole head section. The overhang sections are specifically designed with holes for cooling, while the central pole core section maintains solid structure for optimal magnetic flux conduction and torque generation. This regional differentiation allows each part to fulfill its specific function without compromising the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The pole head section is segmented into functionally distinct zones: the central pole core section and the peripheral overhang sections. This segmentation enables independent optimization of each region - the pole core for magnetic performance and the overhang sections for cooling - thereby resolving the contradiction between cooling requirements and torque generation.

Inventive Principle:
Principle #1Segmentation

2Power

If holes are formed in the overhang section to form flux barriers, then reluctance torque is increased, but the structural integrity may be compromised

Engineering Contradiction:
Improvereluctance torqueVSAvoidstructural integrity
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The invention applies local quality by creating flux barriers specifically in the overhang sections where they are most effective for increasing reluctance torque, while preserving the solid continuous structure in the pole core section. This localized approach to flux barrier formation maximizes the torque enhancement benefit while minimizing the impact on overall structural strength.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The overhang sections act as intermediary elements that can accommodate holes for dual purposes: forming flux barriers to increase reluctance torque and providing cooling channels. These intermediary structures mediate between the conflicting requirements of torque enhancement and structural integrity by being positioned in a region that is less critical for mechanical strength compared to the pole core.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 increases reluctance torque, resulting in more efficient operation of electrical machines by forming a flux barrier in the overhang section, thus compensating for torque reduction.

Implementation Method 1

a first hole is formed in the first overhang section... so that a flux barrier can be formed in the first overhang section through magnetic saturation

Methodology Applied
Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentEP4576501A1Rotor sheet comprising a hole in an overhang section
Publication Date: 2025.06.25 VALEO ELECTRIFICATION
  • EP4576501A1 patent drawingFigure 1
  • EP4576501A1 patent drawingFigure 2
  • EP4576501A1 patent drawingFigure 3~4

AI summary

Rotor lamination (1) for a rotor lamination stack (50), wherein the rotor lamination (1) has: - a yoke section (2) with a central hole (3) through which a rotational axis (4) of the rotor lamination (1) runs, and - a plurality of pole sections (5), each having a pole core section (6) which projects radially from the yoke section (2), and a pole head section (7) which adjoins the pole core section (6) radially on the outside and forms a first overhang section (8) and a second overhang section (9) which project beyond the pole core section (6) on both sides in the circumferential direction, wherein a first hole (10) is formed in the first overhang section (8).