Rotor Lamination Fixation With Axial Tolerance Compensation

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Solution Overview

Problem

Existing electric machine rotor fixing methods require high manufacturing effort, often involving complex machining and adjustments, which increase production costs and time.

Innovation Solution

The laminated core is fixed to the rotor shaft using an end lamination for tolerance compensation, supported by a securing ring pressed onto the rotor shaft, simplifying the manufacturing process and enhancing robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If press fits are provided directly between rotor laminations and rotor shaft, then fixation strength is improved, but manufacturing effort increases due to laborious diameter adjustment and critical region reshaping

Engineering Contradiction:

Improvefixation strengthVSAvoidmanufacturing effort

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

An adapter component is introduced as an intermediary element between the rotor shaft and the rotor laminations. This adapter has a first connection region that connects to the rotor shaft and a second connection region that connects to the rotor laminations, thereby mediating the connection and eliminating the need for complex direct press fits or machining operations on the rotor shaft.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If a nut with groove is used to fix the laminated core, then fixation is achieved, but manufacturing effort increases due to complex machining of threads on rotor shaft

Engineering Contradiction:

Improvefixation stabilityVSAvoidmachining complexity

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The adapter serves as a mediator that replaces the need for threading operations on the rotor shaft. The adapter can be connected to the rotor shaft through simpler means (such as press fit or keyway) and provides the necessary fixation structure for the laminated core, thereby eliminating complex thread machining.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If welded connections are implemented, then fixation strength is improved, but manufacturing effort increases due to separate welding process

Engineering Contradiction:

Improvefixation strengthVSAvoidmanufacturing process complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The mechanical connection through the adapter replaces the need for welded connections. The adapter provides a purely mechanical fixation system that achieves sufficient strength without requiring thermal processing or separate welding operations, thereby simplifying the manufacturing process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If rotor laminations are individually reshaped in critical region, then press fit quality is improved, but manufacturing time increases

Engineering Contradiction:

Improvepress fit qualityVSAvoidmanufacturing speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The adapter is provided as a pre-fabricated intermediary component with standardized dimensions and connection features. This eliminates the need for individual reshaping of each rotor lamination in critical regions, as the adapter handles the dimensional requirements and tolerance compensation, thereby significantly reducing manufacturing time while maintaining press fit quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12212188B2Electric machine with a fixation of multiple rotor laminations to a rotor shaft, said fixation allowing an axial tolerance compensation

Publication Date: 2025.01.28 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

An electric machine for driving a motor vehicle includes a rotor having a central rotor shaft and a laminated core which is made of multiple rotor laminations and is fixed to the rotor shaft. The laminated core is contacted on at least one axial side by an end lamination which produces a tolerance compensation, said end lamination being supported by a securing ring pressed onto the rotor shaft.