Current Control Brush Assembly for Motor Shaft Discharge

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Solution Overview

Problem

Static electrical charges accumulate on motor drive shafts due to friction and variable frequency drive-induced common mode voltages, leading to potential electrical discharges that increase wear and interfere with motor operation.

Innovation Solution

A current control brush assembly with electrically conductive arcuate housing sections and radially inward filaments, coupled via a hinge and locking assembly, transfers electrical charges from the shaft to an electrically conductive housing, dissipating them to ground and preventing discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a one-part ring-shaped housing with filaments is used, then the structure is simple and continuous, but the assembly cannot be easily opened for installation or maintenance

Engineering Contradiction:
Improveease of assemblyVSAvoidhousing structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The housing is divided into two separate arcuate sections that can be independently positioned and assembled. This segmentation allows the housing to be opened for installation of the brush assembly and then closed to form a complete ring structure, resolving the contradiction between ease of assembly and structural continuity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hinge connection transforms the static one-part housing into a dynamic assembly that can transition between open and closed states. This dynamic capability enables easy installation and maintenance while maintaining the structural integrity of the complete ring when closed.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the housing is divided into two sections connected by a hinge, then the assembly becomes easier, but the structural integrity and electrical continuity may be compromised

Engineering Contradiction:
Improveease of assemblyVSAvoidstructural integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The hinge acts as an intermediary element that connects the two housing sections while maintaining both mechanical strength and electrical continuity. This mediator allows the sections to be separately assembled yet function as a unified structurally sound and electrically continuous housing when closed.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a locking assembly is added to secure the housing sections, then the structural integrity improves, but the device complexity increases

Engineering Contradiction:
Improvestructural integrityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is integrated with the hinge assembly, merging the functions of connection and locking into a single unified structure. This integration provides secure structural integrity while minimizing the increase in device complexity by avoiding separate locking components.

Inventive Principle:
Principle #5Merging (Combining)

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

The solution effectively reduces the accumulation of static electrical charges on the shaft, minimizing wear and operational interference by establishing a conductive path to ground, thereby preventing electrical discharges.

Implementation Method 1

a first plurality of electrically conductive filaments extending generally inward along a radial direction from the first electrically conductive arcuate housing section and configured to transfer an electrical charge from a shaft to the first electrically conductive arcuate housing section

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a hinge configured to provide a connection between the first and second conductive arcuate housing sections and to facilitate rotation of the second electrically conductive arcuate housing section relative to the first electrically conductive arcuate housing section

Methodology Applied
Scientific EffectMechanical rotation: Hinge

Data Source

PatentEP2771963B1Current control brush assembly
Publication Date: 2016.06.15 ILLINOIS TOOL WORKS INC
  • EP2771963B1 patent drawingFigure 1
  • EP2771963B1 patent drawingFigure 2
  • EP2771963B1 patent drawingFigure 3

AI summary

A system, in certain embodiments, includes a current control brush assembly including a first electrically conductive arcuate housing section retaining a first set of electrically conductive filaments. The first set of electrically conductive filaments extends generally inward along a radial direction. The current control brush assembly also includes a second electrically conductive arcuate housing section retaining a second set of electrically conductive filaments. The second set of electrically conductive filaments extends generally inward along the radial direction. Furthermore, the current control brush assembly includes a hinge configured to facilitate rotation of the second electrically conductive arcuate housing section relative to the first electrically conductive arcuate housing section about an axis substantially perpendicular to a first axial surface of the first electrically conductive arcuate housing section.