Commutator Ring Reinforcement via Plastic Deformation

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Solution Overview

Problem

Existing methods for producing rolling commutators face challenges in constructing and assembling prestressable ring anchors, which are complex and difficult to manufacture, especially when made from high-tensile, non-extensible materials, leading to potential deformation and increased sparking at high operating speeds due to centrifugal forces.

Innovation Solution

A cylindrical mandrel with a tapered front end is used to press a reinforcement ring into a recess in the commutator ring, securing it through deformation, allowing the reinforcement ring to be made from any suitable material and simplifying assembly, while the recess can be open or closed with an insulating compound for additional security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If prestressable ring anchors are made from high-tensile, non-extensible materials to prevent detachment at high speeds, then reliability is improved, but device complexity increases considerably

Engineering Contradiction:
Improveprevention of detachmentVSAvoidconstruction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the material parameter from high-tensile non-extensible materials to extensible materials that can be elastomeric or rubber-like. This allows the ring anchor to be stretched during assembly and then contract to provide prestressing force, achieving the same functional effect with simpler construction. The extensible nature enables the anchor to be installed by stretching it over the commutator ring and then having it automatically contract to secure itself.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of using rigid high-tensile materials that resist deformation, the invention inverts the approach by using materials that are intentionally designed to deform and stretch. The ring anchor is made from extensible materials that can be stretched during installation and then recover, converting the deformation from a problematic feature into the mechanism for creating prestressing force.

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-affected harmful factors

If complex prestressable ring anchors are assembled to prevent deformation at high speeds, then centrifugal resistance is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvecentrifugal force resistanceVSAvoidassembly simplicity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The ring anchor is designed to be self-installing through its extensible properties. During assembly, the extensible ring anchor is stretched and placed over the commutator ring, then it automatically contracts to secure itself without requiring complex prestressing mechanisms or additional assembly steps. The material's natural elasticity provides the prestressing force, eliminating the need for complex assembly procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

By changing the material parameter to extensible materials, the invention simplifies the manufacturing and assembly process. The extensible nature allows the ring anchor to be easily stretched during installation and then automatically secure itself through contraction, making the entire process straightforward and eliminating complex prestressing procedures.

Inventive Principle:
Principle #35Parameter changes

3Power

If the commutator ring is subjected to strong centrifugal forces at high speeds, then power output is improved, but deformation increases leading to increased sparking

Engineering Contradiction:
Improverotation speed capabilityVSAvoiddeformation and sparking
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The extensible ring anchor acts as a counterbalancing element that provides inward prestressing force to counteract the outward centrifugal forces acting on the commutator ring during high-speed rotation. By pre-tensioning the ring anchor, it creates a compressive prestress that opposes the tensile stresses generated by centrifugal forces, preventing deformation and maintaining dimensional stability at high rotation speeds.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 arming of the commutator ring, enhances its temperature and centrifugal resistance, and eliminates the need for complex prestressing, making the commutator easier to manufacture and assemble, with improved resistance to deformation and accidental loss.

Implementation Method 1

pressing an inner delimitation 56 of the groove 18 in the region of the lamellae 8, which previously diverged towards the end face 54, outwards against an inner peripheral surface of the armoring ring 14 with plastic deformation

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

the commutator ring is subject to strong centrifugal forces, which without suitable countermeasures can lead to an undesirable deformation of the metallic commutator ring

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2206206B1Method for producing a commutator ring for a roll commutator for an electrical machine, and electrical machine
Publication Date: 2011.10.26 ROBERT BOSCH GMBH
  • EP2206206B1 patent drawingFigure 1~2
  • EP2206206B1 patent drawingFigure 3~6
  • EP2206206B1 patent drawingFigure 7~9

AI summary

The invention relates to a method for producing a commutator ring (6) for a commutator (2) of an electrical machine, and to an electrical machine. Laminas (8) of the commutator ring (6) are molded from an electrically conductive deformable strip material (34), the laminas having at least one recess (18; 18, 20), which runs in the longitudinal direction of the strip material (34), before a desired number of the molded laminas (8) is closed into the commutator ring (6). It is provided that after the laminas (8) are closed into the commutator ring (6), a reinforcement ring (14; 15, 16), which is made of an electrically nonconductive deformation-resistant material, is inserted into the recess (18; 18, 20) and fixed in the recess (18; 18, 20) by plastic deformation of the laminas (8) of the commutator ring (6).