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Bearing in ABEC-7(P4) or ABEC-1(P0) for my application?
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●What does Bearing Precision mean?
When dealing with rolling bearings, precision is described by tolerance classes which include dimensional accuracy and running accuracy.it is regulated by ISO or other related standards.
- Dimensional Accuracy includes (the items related to the installation of shaft and outer shell):
1. Allowable deviation (acceptable values) for bore diameter, outer diameter, width and assembled bearing width
2. Bore diameter uniformity as seen in chamfer dimensions
3. Allowable inner ring tapered bore deviation and shape error
4. Average bore diameter variation
5. Outer diameter variation
6. Average outer diameter unevenness
7. Raceway width and height variation (for thrust bearings)
- Running Accuracy includes (items related to the runout of the rotator):
- Acceptable values for inner and outer ring radial runout and axial runout
- Acceptable values for inner ring side runout, and outer ring outer diameter runout
- Permissible variation of raceway thickness of thrust bearing
- Permissible deviation and variation of tapered hole
- Permissible variation of inclination of the outer ring surface
Here I attached the comparison table from different countries:
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The applicable accuracy levels are different according to different types of bearings. The following table shows different types of bearings and their applicable accuracy levels:
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●Application Conditions of Different Accuracy Classes
The vast majority(more than 98%) of ball bearings sold every year belong to the P0(ABEC-1) or P6(ABEC-3) classes. Bearings in higher classes(P5/P4/P2), have much tighter tolerances, called high/super/super high/ultra-precision, require more precise machining and longer production times.
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P0:widely used in bearing systems with rotating accuracy greater than 10 μm. E.g. Variable speed mechanism of ordinary machine tools, Feed mechanism, the Transmission mechanism of automobiles and tractors, Rotating mechanism of general machinery such as general motors, pumps and agricultural machinery, etc.
P6/P5: used in precision bearing systems with rotational accuracy of 5-10μm or high rotational speed. E.g. bearings used in ordinary lathes (Front support-P5, Rear support-P6), Precision instruments, precision rotating mechanisms, etc.
P2: used in ultra-precision instruments with rotational accuracy less than 5μm. E.g. High-precision coordinate borer, Gear system of precision grinder, Precision instruments, High-speed camera, and other precision systems. |
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Choosing a right bearing is critical in your application, with more than 20 years experience, we are aiming to provide our clients with qualified bearings with exact accuracy class you need. |
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