This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Analysis of the Generation Mechanism of Chirp Noises in the Brushes of Blower Motors
Annotation ability available
Sector:
Language:
English
Abstract
This paper describes the self-excited brush vibrations which induce chirp noises in the permanent-magnet direct-current blower motors (150 W) used in automobile air-conditioners.
Based on regeneration of the brush noises and analysis of the brush vibration measurements, we can distinguish two types of brush vibration: one is a high frequency mode, 10 - 20 kHz, which results from coupling the pitching mode and the radial-direction mode of brush; the other is a low frequency mode of the brush which vibrates together with the insulator disk holding the two brushes, 1 - 5 kHz, which results from coupling the yawing mode and the rolling mode. Dynamic models of these two types of vibration and the motion equations are constructed by analyzing the brush vibration measurements, and the mechanisms of generation are confirmed by the eigenvalues and eigenvectors obtained from the motion equations.
We found that the high frequency vibration was caused by the friction between the brush and commutator due to the phase difference between the pitching mode and the radial-direction mode; and that when the rigidity of the insulator disk was insufficient, the low frequency vibration could be caused by the frictional force between the brush and commutator due to the phase difference between the yawing mode and the rolling mode.
These vibrations are self-excited vibrations which occur despite the flat friction coefficient gradient for sliding velocity.
Recommended Content
Journal Article | Property Analysis of an X-Coupled Suspension for Sport Utility Vehicles |
Technical Paper | The Design of a Vehicle Inertia Measurement Facility |
Technical Paper | Active Ride Control - A Logical Step from Static Vehicle Attitude Control |
Topic
Citation
Oya, T., Sekiguchi, T., Mimura, E., and Furukawa, Y., "Analysis of the Generation Mechanism of Chirp Noises in the Brushes of Blower Motors," SAE Technical Paper 961785, 1996, https://doi.org/10.4271/961785.Also In
References
- Ichiki T. et al Brushes for Extra High Altitude Aircraft Service Hitachi Review 40-8 58 64 1958
- Kokubu K. Friction and Wear of Carbon Brush Journal of Japanese Society of Tribologist 12-11 17 26 1967
- Tsuya Y. Environment Effect on the Solid Lubricants Journal of Japanese Society of Tribologist 14-1 13 23 1969
- Kokubu K. et al Commutator Surface Roughness and Brush Vibration Tanso 58 224 234 1969
- Broniarek C. A. et al Mechanical Stability of Solid Brush Current Collection Systems IEEE Transactions on Power Apparatus and Systems PA5-99 6 2413 2421 Nov Dec 1980
- Nakanishi Y. et al Characteristic Analysis for Brush Friction The Transactions of The Institute of Electrical Engineers of Japan, Sectional Committee on Rotating Machines 1987 3
- Gabrielli G. et al Thermoplastic Effects on Slipring Surface Leading to Brush Vibrations IEEE Transactions on Energy Conversion 6-3 522 528 1991
- Swayze J. L. et al Effects of System Dynamics on Friction-induced Oscillations Journal of Sound and Vibration 173 5 599 609 1994
- Oya T. et al Analysis of Generation Mechanism of Brush Vibration Noise in a Small Motor Pitching Mode Vibration, Transactions of the Society of Automotive Engineers of Japan 25 1 95 100 January 1994
- Oya T. et al Analysis of Generation Mechanism of Noise in Brushes of Small Motor the 2nd Report; Yawing Mode Vibration Society of Automotive Engineers of Japan Transactions of Lecture Meeting 993 101 104 May 1993