Angle Measuring Device With Centrifugal Pendulum Damping

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Solution Overview

Problem

Angle measuring devices used in conjunction with electric motors often experience reduced measurement accuracy due to vibrations, leading to inferior performance in machine tools and printing machines, and excessive motor currents causing inefficiencies and noise.

Innovation Solution

An angle measuring device with a pendulum mass connected to the stator, designed to act as a centrifugal pendulum or absorber, providing damping effects across a wide frequency range, and featuring multiple pendulum masses arranged symmetrically with elastic connections to reduce vibrations and maintain measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the angle measuring device uses a rigid connection to ensure measurement stability, then measurement precision is improved, but the device becomes sensitive to vibrations and resonances

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidvibration sensitivity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful vibrations into beneficial damping effects by introducing a pendulum mass that oscillates in response to vibrations. The pendulum mass absorbs vibrational energy through its own oscillations, transforming the harmful vibrations into a controlled damping mechanism that protects the measurement system while maintaining precision.

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

Solution Approach 2:

The pendulum mass acts as an intermediary element between the rigid measurement components and the external vibrations. It mediates the interaction by absorbing and dissipating vibrational energy, preventing direct transmission of harmful vibrations to the measurement system while maintaining the rigid connection needed for accurate measurements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If compensating couplings are made torsionally rigid to improve measurement accuracy, then measurement precision is improved, but vibrations and resonances are amplified

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidvibration stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The pendulum mass converts the problematic vibration-stability conflict into a beneficial damping system. By allowing controlled oscillations of the pendulum mass, the system transforms potential resonance amplification into active vibration damping, maintaining both measurement accuracy and vibration stability simultaneously.

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

3Stability of the object's composition

If vibration damping elements are added to reduce vibrations, then vibration stability is improved, but device complexity increases

Engineering Contradiction:
Improvevibration stabilityVSAvoidstructural complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent achieves vibration damping by changing the dynamic parameters of the system through the pendulum mass. Rather than adding complex passive damping elements, the solution modifies the system's natural frequency and damping characteristics through the pendulum's mass and suspension parameters, providing effective vibration reduction with minimal structural complexity.

Inventive Principle:
Principle #35Parameter changes

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 significantly improves measurement behavior by damping vibrations, ensuring accurate angular position measurement over a large frequency range without reducing accuracy, and reduces motor current errors, leading to improved performance and efficiency.

Implementation Method 1

The pendulum mass acts in particular as a centrifugal pendulum or absorber pendulum. The pendulum mass is only attached to the stator, with the connection to the stator being designed so softly that the pendulum mass follows the movements of the stator with a certain delay. This behavior has a damping effect

Methodology Applied
Scientific EffectCentrifugal pendulum effect: Pendulum

Implementation Method 2

The pendulum mass follows the movements of the stator with a certain delay. This behavior has a damping effect, with the damping effect being ensured over a large frequency range

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 3

The pendulum mass is connected to the body via an elastic element, in particular via a web, a spring or an elastomer part. In particular, the web can have a flexure joint

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2767806B1Angle measuring equipment
Publication Date: 2015.10.14 DR JOHANNES HEIDENHAIN GMBH
  • EP2767806B1 patent drawingFigure 1~2
  • EP2767806B1 patent drawingFigure 3
  • EP2767806B1 patent drawingFigure 4~5

AI summary

The device has a rotor (2) rotatably arranged relative to a stator (1) about an axis in circumferential direction. The rotor is provided with a shaft (2.1), at which a code disk (2.2) is torque-proof secured. The stator includes a body (1.3) and a sampling unit (1.2) for sampling the code disk. A set of pendulum masses i.e. centrifugal force pendulum masses, is connected over two bars with the body, where a direction component is movable parallel to the circumferential direction and relative to the body with the pendulum mass.