|NMB 100% inspects for bearing noise in the
dynamic condition with an Anderon meter.
The Anderon meter inspects for vibration noise of a complete ball bearing.
The system picks up noise and very faint vibrations of a ball bearing directly,
not through the air. Thus, it is not necessary to consider the effect of
airborne noise and vibration.
When the inner ring of ball bearing rotates at 1,800 min-1, vibration occurs to the outer ring. The velocity-type pickup is set up
to contact the outside diameter of the outer ring and it transforms the
value from mechanical vibration in the radial direction to an electric
The vibration noise value is shown on the meter after all frequencies are
separated into three bands. The Anderon meter has an amplifier and speaker
to cover all frequencies besides the shown values. One is also able to
listen to the sound level acoustically with headphones.
The three frequency bands are separated as follows:
||frequency range (Hz)
|L : Low Band
||50 ~ 300
|M : Medium Band
||300 ~ 1800
|H : High Band
||1800 ~ 10000
Anderon Bearing Vibration Meter
It is impossible to see the bearings inside once they are assembled. The noise levels of bearings must be checked when they are rotating. An Anderon meter is used to check the noise of complete bearings. It tells the noise level of each bearing with a certain unit. When noise is checked by the Anderon machine, a specified preload is applied to each different bearing. Mechanical vibration of the bearing outer ring is detected in the radial direction by contacting the outer ring with a velocity pickup, and the signal from the pickup is converted to a variable electrical output. The bearing inner ring is rotated at 1800RPM, and the outer ring is stationary during the measurement. It is possible to detect even small vibrations because a direct detection system is used instead of a system that converts from rotational vibration to air vibration. Vibration from other sources can be eliminated in this method.
About the Anderon Meter and Ball Bearing Vibration
What Is an Anderon Meter?
To understand Anderon values, it may help to have a better understanding of what an Anderon meter is. An Anderon meter is a device that is designed to measure bearing vibration in a given bearing. It does this by providing an Anderon value, a number created specifically for this device, which delineates the degree of vibration in the bearing. This is important because there is a direct relationship between bearing vibration and bearing noise. The Anderon meter can provide a great deal of useful information about a bearing with respect to vibration, including information about surface irregularities and subsequent radial displacement. The Anderon meter makes it easier to determine vibration causes and to sort bearings by precision class, quality, and, naturally, level of vibration and noise.
What Is an Anderon Meter Composed of?
The Anderon Meter measures bearing vibration using three parts: the converter, the driver unit, and the indication unit. The drive unit rotates the ball bearing to generate the vibration to be measured. The converter converts that vibration into electrical signals that can in turn be read by the indication unit, which, along with the ability to listen to the sound frequency produced, provides a digital readout of the Anderon value.
Why Is Vibration of Ball Bearings an Important Issue?
Vibration and noise do not negatively affect the bearing itself and are a natural consequence of the bearing's design. For this reason, it is not often a major focus for those looking for ball bearings for their applications. That being said, heavy vibration and its counterpart, loud noise, can have an additive effect, and if your application is using many high vibration ball bearings, you may see significant noise or vibration in your application, and this may not be desirable.
Consider, for example, an air conditioner. While very loud noise or significant vibration may not affect how well the device cools a room, it still may not be desirable and may be a deterrent to someone considering purchasing the device. When it comes to something like washing machines, some people may simply expect loud noise and vibration, and be contented with the fact that the machine is usually working away hidden in a basement, while others may consider quiet, low vibration operation a selling point. Also consider applications like medical equipment that might be used in a hospital. In this environment, precision and quiet are both highly desirable, so ball bearings with low vibration and noise values will be preferred.
Because we are aware that while not all applications using ball bearings require low vibration and noise, many do, NMB designs ball bearings with noise sensitive applications in mind.