Engineering topics

Kremmer, I.

Publications and source records attributed to Kremmer, I..

3 records

NASA NTRS1974

Photoelectronic vibrometer with polarized light

A seismic torsiometer is described which is based on the reception by a photosensitive transducer of a light flux modulated by a relative rotation of the optical axes of two polaroids. The torsional vibrations of the polaroid fixed to the shaft are transmitted to the other polaroid (which at the same time is the seismic mass of the apparatus) by means of elastic lamellas. The device can work as accelerometer, vibrometer or frequency meter, depending on the value of the ratio between the proper oscillation frequency of the seismic system and the measured vibration frequency.

Kremmer, I.↗

NASA NTRS1974

Considerations on the acoustic energy radiated by toothed gears

A mechano-acoustic model is reported for calculating acoustic energy radiated by a working gear. According to this model, a gear is an acoustic coublet formed of the two wheels. The wheel teeth generate cylindrical acoustic waves while the front surfaces of the teeth behave like vibrating pistons. Theoretical results are checked experimentally and good agreement is obtained with open gears. The experiments show that the air noise effect is negligible as compared with the structural noise transmitted to the gear box.

Popinceanu, N. G.↗

NASA NTRS1974

Contributions to the reduction of gear noise

The influence of profile displacements on the acoustic pressure level of running gears is studied. The conclusion is reached that extra polar gears function well, reducing the acoustic pressure level by about 2-3 db which, at the level of the total noise of 80-90 db, can be easily felt. This result can be explained by the fact that in this gear the pitch point is situated outside of the gearing segment, so that a certain change in the direction of the friction force between the tooth flanks is eliminated.

Kremmer, I.↗