Piezo Drive Damping Layer Resonance Control

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Solution Overview

Problem

Piezo drives in geodetic and coordinate measuring devices face challenges with unwanted vibrations and noise, power losses, and thermal expansion issues due to the interaction between piezo oscillators and running surfaces, particularly in rotating configurations with ceramic components, which affect precision and reliability across varying temperatures and humidity levels.

Innovation Solution

The solution involves designing the connection between the running surface components and their receptacles with an intermediate layer that provides mechanical decoupling and damping, using a soft adhesive with fillers to shift natural resonances outside the operating window of the piezoelectric drive, and incorporating a damping layer to absorb vibration amplitudes and maintain stability across temperature ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a ceramic ring is used as the running surface component to reduce wear, then durability is improved, but unwanted vibrations and noise increase due to resonance excitation

Engineering Contradiction:
ImprovedurabilityVSAvoidunwanted vibrations and noise
Core Design Contradiction:
Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

An intermediate layer is introduced between the ceramic ring and the receptacle to act as a mediator that dampens vibrations and reduces noise. This layer absorbs the harmful vibrational energy generated during operation while allowing the ceramic ring to maintain its wear-resistant properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The resonance vibrations that initially cause harmful noise and vibrations are converted into beneficial damping effects through the intermediate layer. The layer is designed to absorb these vibrations and dissipate them as heat, transforming the harmful resonant energy into a stabilizing force that reduces noise and vibration.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Stability of the object's composition

If the running surface component is rigidly connected to the receptacle, then structural stability is improved, but natural resonances fall within the operating frequency window causing vibrations

Engineering Contradiction:
Improvestructural stabilityVSAvoidvibrations
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The connection parameters between the running surface component and receptacle are changed by introducing an intermediate layer with specific damping properties. This layer modifies the natural frequencies of the system, shifting them outside the operating frequency window to avoid resonance-induced vibrations while maintaining structural stability.

Inventive Principle:
Principle #35Parameter changes

3Strength

If ceramic components are used, then compressive strength is improved, but tensile strength is weak and statistically widely scattering

Engineering Contradiction:
Improvecompressive strengthVSAvoidtensile strength consistency
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A composite structure is created by combining the ceramic running surface component with a damping layer material that has complementary mechanical properties. This composite construction compensates for the weak and variable tensile strength of ceramic while preserving its high compressive strength and wear resistance.

Inventive Principle:
Principle #40Composite materials

4Productivity

If the piezo oscillator operates at high frequency, then productivity is improved, but power losses and noise increase due to resonance

Engineering Contradiction:
Improveoperating speedVSAvoidpower losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The intermediate damping layer converts the harmful resonant vibrations that cause power losses into beneficial vibration absorption. By dissipating the resonant energy as heat rather than allowing it to propagate through the system, the layer reduces power losses and noise while enabling high-frequency operation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 approach reduces unwanted vibrations and noise, enhances power efficiency, and ensures reliable operation across a wide temperature range by optimizing the vibration behavior and resonance frequencies, thereby improving the precision and durability of piezo drives in high-precision devices.

Implementation Method 1

an intermediate layer, in particular in the form of an adhesive layer, which has decoupling and/or damping properties

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

the components and their connection are designed so that any interfering resonances in the running surface components and their receptacles are placed or shifted

Methodology Applied
Scientific EffectMechanical decoupling:

Implementation Method 3

The spatially oscillating or oscillating movement is brought about by the coordinated arrangement and interconnection of piezoelectric materials

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 4

the contact element contacting the running surface under pressure causing an advance. This coupling transmits a driving force

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 5

the adhesive layer, in particular the joint gap and running surface geometry are matched to one another and, if necessary, by adding fillers, the adhesive bond is optimized so that the resonances do not lie within the operating window

Methodology Applied
Scientific EffectResonance frequency shifting: Resonance

Data Source

PatentEP2415091B1Piezo drive
Publication Date: 2014.04.30 LEICA GEOSYSTEMS AG
  • EP2415091B1 patent drawingFigure 1~2b
  • EP2415091B1 patent drawingFigure 3~5
  • EP2415091B1 patent drawingFigure 6~7

AI summary

The invention relates to a piezo drive, in particular for use in geodesic devices, having at least one piezoelectric motor element (2) that includes an advancing component, a running surface component (10C), and a receptacle for the running surface component (10C), wherein said receptacle is to be connected to a component to be driven, wherein the piezoelectric motor element (2) has a window of operation of the motor as a frequency range of the movement of the advancing component. The running surface component (10C) and the receptacle (9C) are sized and connected to one another such that the natural resonances of the running surface component (10C) lie outside the window of operation of the motor.