Quality testing process

• US 20050188767A1
• Filed: 04/18/2005
• Published: 09/01/2005
• Est. Priority Date: 10/17/2002
• Status: Active Grant

• Current Assignee: BSH Bosch und Siemens Hausgerã¤Te GmbH (Robert Bosch GmbH)
• Original Assignee: BSH Bosch und Siemens Hausgerã¤Te GmbH (Robert Bosch GmbH)
• Inventors: Wang, Zhiguo, Micko, Jan, Melz, Matthias
• Granted Patent: US 7,174,786 B2
• Time in Patent Office: Days
• US Class Current: 73/579
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/2693 Rotor or turbine parts
• CPC Class Codes: G01N 29/11 by measuring attenuation of acoustic waves
• CPC Class Codes: G01N 29/12 by measuring frequency or resonance of acoustic waves measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00
• CPC Class Codes: G01N 29/42 by frequency filtering or by tuning to resonant frequency
• CPC Class Codes: G01N 29/48 by amplitude comparison

Abstract

A process is performed for testing the quality of a unit such as an electromotor, which has at least one mobile part, which is mobile within a given frequency range with varying frequencies and is capable of exciting the unit to oscillate. In the method, a frequency of the mobile part at least within a first interval of the frequency range is varied with a first rate of change. The frequency of the mobile part within at least a second interval of the frequency range is varied with a second rate of change. The second rate of change is lower than the first rate of change. The oscillation amplitude of the unit is recorded and the unit is assessed as useful or unusable by evaluation of the recorded oscillation amplitude.

Claims

1. A process for testing a quality of an unit having at least one mobile part being mobile within a given frequency range with different frequencies and capable of exciting the unit to oscillate, which comprises the steps of:

a) varying a frequency of the mobile part at least within a first interval of the given frequency range with a first rate of change;

b) varying the frequency of the mobile part within at least a second interval of the given frequency range with a second rate of change, the second rate of change being lower than the first rate of change;

c) recording an oscillation amplitude of the unit resulting in a recorded oscillation amplitude; and

d) analyzing the recorded oscillation amplitude for assessing the unit as useable or unusable.

2. The process according to claim 1, which further comprises evaluating the recorded oscillation amplitude obtained during step a) for ascertaining the second interval of the given frequency range to be tested during step b).

3. The process according to claim 1, which further comprises:

carrying out step a) completely for the given frequency range fully with the first rate of change; and

carrying out step b) for the second interval of the given frequency range with the second rate of change.

4. The process according to claim 1, which further comprises carrying out the given frequency range continuously, whereby a rate of change within each second interval is maintained at the second rate of change and outside each of the second intervals the rate of change is carried out with the first rate of change.

5. The process according to claim 1, which further comprises establishing the second interval prior to carrying out steps a) and b).

6. The process according to claim 5, which further comprises establishing at least the second interval by recording the oscillation amplitude of a comparable unit with the unit to be tested in dependence on the frequency.

7. The process according to claim 1, which further comprises using an electric machine as the unit.

8. The process according to claim 1, which further comprises using an electromotor as the unit.

9. The process according to claim 1, which further comprises setting the second rate of change to be less than a quarter of the first rate of change.

10. The process according to claim 1, which further comprises setting the second rate of change to be less than a tenth of the first rate of change.