SKF - ложь и правда об ABEC.

True / False statements on the market

ABEC

True:

ABEC is the american standard, determining dimensional tolerances for ball bearings

False, ABEC5 defines:

• clearence radial/axial
• lubricants
• cage
• seal
• bearing material
• tolerances for friction

definitely False:

• ABEC5 or ABEC7 bearings are running faster than ABEC1 bearings
• ABEC1 bearings give better service life than ABEC5 bearings

Cage

True:

• cage precision has an influence on performance
• polymer cage withstands higher shockloads under misaligned conditions
• standard steel/brass cages give less friction than other cages
• massiv brass cages are tougher than standard steel/brass cages

False:

• standard brass cage performs better than standard steel cage
• polymer cage is the best in any case

Lubrication

True:

• every bearing requires a lubricant
• without lubricant, you get hot runners
• kind and amount of lubricant has a strong influence on the bearing friction and service life
• usually, you have poor service life with oiled bearings compared to greased bearings

False:

• ABEC7 bearings are oiled only
• grease is grease, all are the same

Sealing

True:

• "Z" in designation indicates non contacting seal
• "S" in designation indicates contacting seal
• "R" means "Rubber" or "rubberized"
• contacting seals (2RS1) give better protection against contamination and water than non contacting seal (2Z, ZRZ)
• protection against water of non contacting seals is poor
• one function of a seal is to keep the lubricant inside the bearing

False:

• all Z-shield perform equally
• Z-shield with snapring (serviceable) are better than others
• rubberized seals are contacting and have high friction (valid for RS1 only, not for RZ)
• 608-Z is ok, you do not need 2Z-shields (-Z only does not keep lubricant inside the bearing

Maintenance

True:

• ZZ-bearings with snap ring are serviceable, but you have to maintain them
• RZ-bearings are serviceable, but it is usually not required to do so
• if you regrease your bearing, it has to be done under very clean conditions
• it is possible to do failures, which causes more trouble than you had before
• with wrong maintenance you create more new problems as you solve

False:

• a damaged bearing will be as new after maintenance

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