Composite Thrust Washer Damping Armature Vibration

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Solution Overview

Problem

Existing thrust washers for electrical machines fail to adequately dampen armature longitudinal vibration, leading to noise excitation, and are costly due to the need for additional components like corrugated rings.

Innovation Solution

A thrust washer composed of a hard and soft component, where the soft component forms the radial contact section with the rotor or bearing, and the hard component absorbs axial forces, enhancing damping without additional parts, and using the same material like Hytrel with varying Shore D hardness for reduced axial rigidity and improved damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a single-material thrust washer is used, then the structure is simple, but the damping of armature longitudinal vibration is insufficient leading to noise excitation

Engineering Contradiction:
Improvenoise excitationVSAvoidthrust washer structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The thrust washer is constructed from two different elastomeric materials with distinct Shore A hardness values. The first material (softer, lower Shore A) provides superior vibration damping to reduce noise excitation, while the second material (harder, higher Shore A) ensures wear resistance and structural stability. This composite material approach resolves the contradiction by integrating both damping and structural requirements into a single multi-material component.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the thrust washer are assigned different material properties tailored to their specific functional requirements. The region contacting the rotor or armature uses the softer material optimized for damping longitudinal vibrations, while the region interfacing with the bearing uses the harder material for enhanced wear resistance. This localized differentiation allows the single component to simultaneously address noise reduction and durability without requiring additional parts.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If additional components like corrugated rings are added to improve damping, then the damping performance improves, but the cost and device complexity increase

Engineering Contradiction:
Improvearmature longitudinal vibrationVSAvoidnumber of components
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention merges the functions of vibration damping, wear resistance, and structural support into a single thrust washer component. By integrating two elastomeric materials with complementary properties directly into one piece, the design eliminates the need for separate damping elements like corrugated rings or additional washers, thereby reducing component count while achieving superior damping performance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The use of composite elastomeric materials within the thrust washer provides inherent vibration damping capabilities without requiring additional damping components. The softer material region specifically targets longitudinal vibration damping, while the harder material region maintains structural integrity, allowing the single component to replace multiple functional elements.

Inventive Principle:
Principle #40Composite materials

3Reliability

If a hard material is used for the thrust washer, then the wear resistance improves, but the damping of longitudinal vibration decreases leading to noise

Engineering Contradiction:
Improvewear resistanceVSAvoidnoise excitation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The thrust washer employs a composite structure with two elastomeric materials of different hardness. The softer material (lower Shore A) provides the damping necessary to suppress longitudinal vibrations and reduce noise, while the harder material (higher Shore A) delivers the wear resistance required for reliable operation. This material differentiation resolves the contradiction between damping and wear resistance within a single component.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The softer material is positioned in the region that contacts the rotor or armature where vibration damping is most critical for noise reduction, while the harder material is placed in the region interfacing with the bearing where wear resistance is paramount. This spatial differentiation of material properties allows each region to optimize its performance for its specific functional demand.

Inventive Principle:
Principle #3Local quality

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 design effectively reduces noise excitation and increases wear resistance while simplifying the machine design, achieving improved damping of armature longitudinal vibration without additional components and reducing noise generation.

Implementation Method 1

By skilfully selecting the elasticity and damping of the thrust washer, it is possible to modify the excitation of the axial vibration to such an extent that it is damped during operation

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the soft component counteracts the longitudinal vibration of the armature and prevents a corresponding excitation

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2710712B1Thrust washer for an electric machine
Publication Date: 2015.05.20 ROBERT BOSCH GMBH
  • EP2710712B1 patent drawingFigure 1
  • EP2710712B1 patent drawingFigure 2

AI summary

The invention relates to a thrust washer (28) for an electric machine (10, 12) intended to be arranged on a shaft (16) between a bearing (18) and a rotor (14), preferably a rotating electrical contact element (24) impacted by brushes (38), and/or a disk pack (36) of the rotor (14). The thrust washer (28) is provided with an area for sealing having two end faces (32, 34). On each end face (32, 34), at least one radial abutment section (50, 52) for the bearing (18), or the rotor (14), is provided. The thrust washer (28) according to the invention is characterized in that it is made of at least one hard component (54) and one soft component (56), wherein the part of the radial abutment section (50, 52) abutting the rotor (14) and/or the bearing (18) is formed by the soft component (56).