linear bearing noise attenuation

[GordonBishop]

With linear ball bearings, every application I have seen the bearings make some noise. A client expects a machine I am working with to be silent. I have exhausted my options in terms of different bearings and greases(frelon type bushings won't work here), and need to look into designing an enclosure to keep it quiet. I don't really know where to start. I am completely new to acoustics. any tips or references?

Thanks

Gordon

 

[ccw]

Hi GordonBishop,
Please give some more description and clues. Is this device related to a translating carriage on ball/slides? Does the noise have a dominant frequency, that relates to, say, the translation speed?

 

[InspectorGadget]

One of the causes of excessive noise is the response of the structure to exciting forces created at the interface of the bearing with the shaft carrier.It may not be the bearings.

Are you using a precision solid shaft? The shaft should be made to a max roughness of 0.3 micrometers Ra. Also wear of the surface can quickly occur if it does not have appropriate hardness between 60-64 HRC (unless stainless is necessary 55-58HRC). The shaft diameter tolerances should conform to a minimum of h6 and can be supplied by SKF up to h9.

In addition you may consider using a fully supported shaft design with open linear bearing units to dampen vibration. SKF has several publications dealing with linear motion available at 610.861.4800. You can also talk to one of our engineers at the same number.