sleeve bearings
sleeve bearings
Author :Admin | Publish Date:2013-04-18 10:32:45
Some bearings use a thick grease for lubrication, which is pushed into the
gaps between the bearing surfaces, also known as packing. The grease is held in
place by a plastic, leather, or rubber gasket (also called a gland) that covers
the inside and outside edges of the bearing race
to keep the grease from escaping.Bearings may also be packed with other
materials. Historically, the wheels on railroad cars used sleeve bearings packed
with waste or loose scraps cotton or wool fiber soaked in oil, then later used
solid pads of cotton.
Sleeve bearings use two surfaces lubricated with oil or grease as a
friction contact. They often use porous sintered sleeves to be self-lubricating,
requiring only infrequent maintenance or replacement. Sleeve bearings are less
durable at higher temperatures as the contact surfaces wear and the lubricant
dries up, eventually leading to failure; however, lifetime is similar at
relatively low ambient temperatures. [Sleeve bearings]
may be more likely to fail at higher temperatures, and may perform poorly when
mounted in any orientation other than vertical. The lifespan of a sleeve-bearing
fan may be around 40,000 hours at 50 °C. Fans that use sleeve bearings are
generally cheaper than fans that use ball bearings, and are quieter at lower
speeds early in their life, but can become noisy as they age.
Rifle bearings are similar to sleeve bearings, but are quieter and have
almost as much lifespan as ina bearings. The
bearing has a spiral groove in it that pumps fluid from a reservoir. This allows
them to be safely mounted with the shaft vertical (unlike sleeve bearings),
since the fluid being pumped lubricates the top of the shaft.The pumping also
ensures sufficient lubricant on the shaft, reducing noise, and increasing
lifespan.
Though generally more expensive, ball bearing fans do not suffer the same
orientation limitations as sleeve bearing fans, are more durable at higher
temperatures, and are quieter than sleeve-bearing fans at higher rotation
speeds. The lifespan of a ball bearing fan may be over 60,000 hours at 50
°C.
The sleeves facilitate bearing mounting and dismounting and often simplify
bearing arrangement design.When sealed bearings are to be mounted on an adapter
sleeve it is necessary to protect the sealing lips from being damaged. This can
be done by using an E-design adapter sleeve,inserting an intermediate ring
between the skf bearing and the locking
washer.
To seal efficiently, radial shaft seals must run against a smooth, round
counterface. If the counterface becomes worn, the seals will no longer be able
to fulfil their function, which is to retain lubricant and exclude
contaminants.
B25-163AZNXC3
B25-164AZNXC3
B8-85T12DDNCXMC3E
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