Rotor Support Ring Bayonet Star Disk Design

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Solution Overview

Problem

Existing support devices for rotor windings in internal-rotor synchronous machines face challenges in maintaining stability at high rotating speeds due to mechanical stress from centrifugal forces, leading to inefficiencies and reduced strength, as traditional metallic support rings create electromagnetic short circuits and require additional materials and installation space.

Innovation Solution

A support device featuring a star disk with a ring carrier, supporting teeth, and collar-type end pieces that use bayonet closure regions for a form-fitting and force-fitting connection with a support ring, eliminating the need for separate connection elements and reducing material usage, while providing enhanced stability through a plastics-metal hybrid construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic tie rods are used for fastening the support rings to the star disk, then the support ring is securely held for high rotating speeds, but installation space and material requirements increase

Engineering Contradiction:

Improvestability of support ringVSAvoidmaterial requirement

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The support ring is integrated directly with the star disk through a unified connection structure, eliminating the need for separate metallic tie rods. The support ring features a continuous circumferential connection to the star disk, merging two previously separate components into a single integrated assembly that reduces material usage while maintaining structural integrity at high rotating speeds.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The metallic tie rods are completely removed from the design. Instead of using separate fastening elements, the support ring is directly connected to the star disk through integrated bayonet closure regions, extracting the unnecessary intermediate components that consumed additional material and installation space.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If metallic tie rods are used for fastening the support rings, then the support ring is securely held, but an electromagnetic short circuit cage is created generating additional losses

Engineering Contradiction:

Improvestability of support ringVSAvoidelectromagnetic losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The metallic tie rods that created the electromagnetic short circuit cage are completely removed. The support ring is instead connected through non-conductive or minimized conductive paths that prevent the formation of closed electromagnetic loops, eliminating the source of additional electromagnetic losses while preserving mechanical stability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

An intermediate connection structure is introduced between the support ring and star disk that prevents direct metallic contact paths. The bayonet closure regions use a combination of mechanical interlocking and minimized electrical contact, acting as an intermediary that maintains structural integrity while breaking the electromagnetic short circuit path.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If welding or screw-fitting the support ring to the star disk, then the support ring is securely attached, but the strength of the rotor is reduced

Engineering Contradiction:

Improveattachment stabilityVSAvoidstrength of rotor

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The support ring and star disk are designed as an integrated assembly with continuous material flow between components. The bayonet closure regions create a seamless connection without discrete attachment points, merging the two components into a unified structure that eliminates stress concentration points and maintains overall rotor strength.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Instead of attaching the support ring to the star disk through separate fastening operations (welding or screw-fitting), the design inverts the approach by making the support ring an integral part of the star disk structure from the beginning. The connection is built-in through the molding process rather than added subsequently, avoiding the creation of weak points.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS11349367B2Support device for a rotor of a separately excited internal-rotor synchronous machine consisting of a support ring and a star disk

Publication Date: 2022.05.31 BAYERISCHE MOTOREN WERKE AG

AI summary

A support device for a rotor of an internal-rotor synchronous machine of a motor vehicle includes a star disk, which is able to be arranged on the laminated core of the rotor between an end side of the laminated core and end windings of the rotor windings, and a support ring for encasing the star disk. The star disk has a ring carrier for arranging on a rotor yoke of the laminated core, supporting teeth, protruding radially from the ring carrier, for arranging on rotor teeth of the laminated core, and collar-type end pieces, protruding axially from ends of the supporting teeth, for arranging on pole shoes of the rotor laminated core. The end pieces of the star disk and the support ring have mutually complementary bayonet joint regions, which are designed to connect the star disk and the support ring in a form-fitting manner.