Symmetrical Ripple Spring for Electrical Machine Stator Retention

Solution Overview

Problem

Existing ripple springs with asymmetrical stacks in electrical machines are prone to cracking, leading to reduced retaining force and potential failure of stator bar windings due to uneven internal spring forces, causing vibration and insulation damage.

Innovation Solution

A ripple spring with a symmetrical stack of laminated layers, utilizing alternating fiber orientations and suitable binder materials, such as epoxy or carbon fibers, to enhance bending strength and crack resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If asymmetrical stack design is used in ripple springs, then manufacturing is simpler, but bending strength is reduced and cracking occurs

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidbending strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent applies asymmetry in reverse - it uses a symmetrical stack design where layers are arranged symmetrically about the centerline. This symmetrical arrangement creates uniform internal spring forces that prevent cracking while maintaining manufacturing feasibility through consistent layering patterns.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent employs composite material construction with multiple layers of spring material laminated together in a symmetrical configuration. This composite structure distributes stresses uniformly across all layers, significantly enhancing bending strength and crack resistance compared to single-layer or asymmetrical designs.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If asymmetrical stack design is used in ripple springs, then manufacturing is simpler, but reliability is reduced due to cracking and malfunction

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidcrack resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry in reverse - it uses a symmetrical stack design where layers are arranged symmetrically about the centerline. This symmetrical arrangement creates uniform internal spring forces that prevent cracking while maintaining manufacturing feasibility through consistent layering patterns.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The symmetrical multi-layer design acts as a preventive measure against cracking before it occurs. The uniform stress distribution and enhanced bending strength provided by the symmetrical composite structure cushion against the development of cracks under operational loads, thereby improving reliability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If retaining force is reduced due to loose wedge system or malfunctioning ripple springs, then device complexity is reduced, but harmful vibrations and insulation damage occur

Engineering Contradiction:

Improvewedge system complexityVSAvoidvibration and insulation damage

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent employs composite material construction with multiple layers of spring material laminated together in a symmetrical configuration. This composite structure distributes stresses uniformly across all layers, significantly enhancing bending strength and crack resistance compared to single-layer or asymmetrical designs.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The symmetrical multi-layer design acts as a preventive measure against cracking before it occurs. The uniform stress distribution and enhanced bending strength provided by the symmetrical composite structure cushion against the development of cracks under operational loads, thereby improving reliability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS8400042B2Ripple spring

Publication Date: 2013.03.19 GE INFRASTRUCTURE TECH LLC

AI summary

A ripple spring is provided having one or more layers laminated together, where the one or more layers form a symmetrical stack.