Truck Fleet Maintenance using the Son-Tector ultrasonic detector





	World Headquarters: P.O. Box 250 El Prado, New Mexico 87529 USA Phone/FAX: 575.758.4555 sales@ansonics.com © 2007 Ansonics, Inc. All right reserved. SON-TECTOR and SON-CASTER are trade names of Ansonics, a division of Taos Techsonics, Inc.

Manufacturing ultrasonic detectors since 1963 Home | Contact Us


	Applications & Industries
	Applications & Industries Ç Learn More

Truck Fleet Maintenance
ULTRASONICS: no longer a space-age technology cont	Page 1 2 3

Wheel bearings A ball or roller bearing that's in good condition and is adequately lubricated normally produces a soft "whirring" sound via earphones. Lack of lubrication introduces scraping sounds. Flat spots or nicks on the bearings or race cause a grating, grinding or clicking noise, depending on the speed of rotation and the degree of damage. For best results, it's recommended that the contact probe should touch the spindle. Spin the wheel with a spinner or by hand. If questionable sounds are heard, it's often possible to determine whether it originates from the inner or outer bearing. Simply contact the spindle on both sides of the wheel. Again headphones might be useful in a noisy maintenance facility.
		A contact probe is used to diagnose bearing problems.

Drive train bearings and gears
Ultrasonic inspection has a definite advantage over audible inspection because ultrasonic waves don't propagate through equipment and compound themselves. Thus, the source of ultrasonic sound always gives off the strongest signal and can be accurately pinpointed. In many cases, a stethoscope tends to lead away from the sound source.

Using the contact probe with earphones, it's possible to determine which gear or bearing in a drive is faulty. This should be done by allowing the drive train to run with the wheels raised off the ground. The contact probe and headphones are the search combination to discover the point of greatest noise generation.

Many sounds that interfere when attempting to use a conventional stethoscope don't exist at ultrasonic frequencies. This also contributes to the overall effectiveness of the technique by reducing confusing background noises.

Hydraulic systems Partially blocked or bypassing valves in high pressure hydraulic systems can be extremely difficult and costly to locate.
		Disassembly is not required to detect internal leakage.
However, maintenance managers may find that an ultrasonic detection device is extremely helpful in spotting them by touching the contact probe to suspected fittings, valves and power cylinders. Since hydraulic systems employ very high pressure, the intensity of the sound given off b y an internal leak is extremely high. For most effective operation, amplification on the detector shouldn't be adjusted any higher than is necessary for a clear and distinct ultrasonic signal. Greatest sensitivity is obtained when the amplified sound can be barely heard. When sweeping with the hand probe, don't move too rapidly. A signal source could easily be overrun. Also keep in mind that when using the contact probe, put enough pressure on the probe for a good contact. Be sure to place the probe in the same spot when making repeated tests on the same components.

The above article reprinted with permission from
Fleet Maintenance & Specifying, July 1978

Home | Contact Us