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Verfahren und Vorrichtung zum Messen von Unwuchten an rotierenden Koerpern

Use of laser vibrometer equipment to both measure and correct rotor imbalance in real time.
: Kalkowski, G.; Risse, S.; Guyenot, V.

Frontpage ()

DE 1998-19828498 A: 19980626
DE 1998-19828498 A: 19980626
EP 1999-111889 A: 19990621
EP 969274 A2: 20000105
DE 19828498 C2: 20010705
EP 969274 A3: 20010725
Patent, Electronic Publication
Fraunhofer IOF ()

Die Erfindung betrifft ein Verfahren und Vorrichtung zum Messen von Unwuchten an rotierenden Koerpern, die den hierfuer erforderlichen Aufwand verringern, die Messgenauigkeit erhoehen und mit denen Unwuchten auch an relativ kleinen und/oder leichten Rotoren bestimmt werden koennen. Erfindungsgemaess wird dabei so vorgegangen, dass mit einem Sensor ein Signal zur Zuordnung der Phase von Messsignalen bezueglich der azimutalen Lage eines Rotors und mit mindestens zwei Laservibrometern, lokal voneinander getrennt, der jeweilige Schwingungsweg und/oder die Schwingungsgeschwindigkeit am Rotor und/oder seiner Lagerung in radialer Richtung zeitaufgeloest gemessen werden.


EP 969274 A UPAB: 20000209 NOVELTY - The machine includes a sensor assigning phase to rotor (1) angular position and two or more, separated laser vibrometers. Each measures radial, vibratory, rotor- and/or bearing (4, 11) displacement and/or -velocity, as a function of time. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for balancing equipment. Preferred Features: Coherent light beams from laser vibrometer light sources (L1, L2) are directed normally to the rotor axis, onto its and/or the bearing surfaces. Each reflected beam interferes with a laser vibrometer reference beam, the result determining vibratory displacement and/or velocity. The laser vibrometer is moved along the axis, to carry out separate localized measurements. Measurements are taken at differing rotary speeds. Signals are transformed for digital or analog processing and analysis in real time, converting from time- to frequency domain, measuring amplitudes and phases. Back-transformation determines specific amplitudes or phases in the time domain. At given speeds, defined local imbalance is caused by mass alteration, to determine inherent rotor imbalance. Amplitudes and/or phases are determined outside the rotation frequency, to detect and characterize the natural, self-sustaining rotor vibrations. An optical focusing system (F1, F2) varies the size of the laser beam measurement point on rotor and/or bearings. The rotor is an assembly, in which contributions of its components to imbalance are determined by measurements at successive stages of assembly. Individual components are balanced after each measurement. Imbalance is corrected directly on each component. To balance, an adhesive is added in measured quantity, and hardened by UV light. Following measurement, mass is removed judiciously by a cutter or grinder rotating synchronously with the rotor, advanced to and retracted from it. USE - For high precision balancing of any rotating object or rotor assembly. ADVANTAGE - The system dispenses with mechanical devices and connections, by use of laser beams. It greatly increases measurement accuracy, and reduces equipment cost. It is capable of measuring imbalance on relatively small and/or light rotors. Displacement measurement accuracy is e.g. 2 nm at 20 kHz. Measurable velocity is down to some 300 nm/s. Measurement takes place in real time. Correction can follow immediately as indicated, without even stopping the rotor.