Short-Circuit Ring Recess for Cage Bar Compression

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Solution Overview

Problem

The formation of squirrel-cage rotors requires complex devices and expensive tools, making the process inefficient and costly, especially for high-performance dynamo-electric rotary machines.

Innovation Solution

A short-circuit ring with at least one indentation is used, allowing for mechanical and electrical connection to cage bars through compression, eliminating the need for expensive tools and materials like solder or copper die-casting, by forming a form-fitting connection with the cage bars.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional methods (soldering, copper die-casting, welding) are used to connect short-circuit ring to cage bars, then reliable electrical and mechanical connection is achieved, but complex devices and expensive tools are required

Engineering Contradiction:
Improveconnection reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical connection systems (soldering equipment, die-casting machines, welding devices) with a simple compression-based mechanical connection. The short-circuit ring has protrusions that fit into recesses in the cage bars, creating a form-fitting connection through compression forces alone, eliminating the need for thermal or complex mechanical joining processes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The connection structure is designed to be self-securing through the form-fitting geometry of protrusions and recesses. The compression force automatically creates the connection without requiring external control systems, sensors, or complex actuation mechanisms, making the system self-sufficient and simple

Inventive Principle:
Principle #25Self-service

2Reliability

If traditional methods (soldering, copper die-casting, welding) are used to connect short-circuit ring to cage bars, then reliable electrical and mechanical connection is achieved, but expensive tools and materials are required

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs simple, inexpensive compression tools rather than expensive specialized equipment. The connection structure itself uses basic geometric features (protrusions and recesses) that can be manufactured with standard machining processes, eliminating the need for costly soldering materials, die-casting molds, or welding consumables

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If traditional methods (soldering, copper die-casting, welding) are used to connect short-circuit ring to cage bars, then reliable electrical and mechanical connection is achieved, but energy consumption increases due to heating requirements

Engineering Contradiction:
Improveconnection reliabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces thermal energy-based connection methods (soldering, welding) with a purely mechanical compression-based connection. The form-fitting protrusion-recess structure creates reliable electrical and mechanical contact through compression forces alone, eliminating the need for heating equipment and thermal energy input

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This method simplifies the production of squirrel-cage rotors, reduces production costs, and saves energy by avoiding the need for heating materials, while maintaining a robust and efficient connection, suitable for both small and large batches of rotors.

Implementation Method 1

the short-circuit ring being connected to the cage bar by means of compression of the cage bar

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

Deforming the cage bar by compression

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3721536B1Connection of short circuit ring and cage rod for a short-circuit cage
Publication Date: 2022.01.12 SIEMENS AG
  • EP3721536B1 patent drawingFigure 1~3
  • EP3721536B1 patent drawingFigure 4~6
  • EP3721536B1 patent drawingFigure 7~8

AI summary

The invention relates to a short-circuit ring (1, 11) for a squirrel cage of a dynamo-electric rotary machine (M), wherein the short-circuit ring (1, 11) has at least one recess (2, 12). The short-circuit ring (1, 11) can be connected to at least one cage bar (4) protruding from a rotor packet (5) of the dynamo-electric rotary machine (M) by means of the recess (2, 12). The invention also relates to two methods for connecting a short-circuit ring (1, 11) of this type.