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SHIELDS AND SEALS
| A
shield (non-contact) or seal (contact) is often installed to retain
lubricant and to prevent contamination from entering the bearing
raceways. These are available in a variety of materials and configurations.
Standard shield and seal configurations are called out in the
individual bearing tables on pages 46-57. Please contact a Dynaroll
bearing engineer to discuss any special requirements. |
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| SHIELDS
AND SEAL TYPES |
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Z
TYPE SHIELD This is the
most common type of shield. It is non-removable, being permanently
staked to the bearing outer race with a small gap of approximately
.005 inches between the inside diameter of the shield and the
bearing inner ring. Since there is no contact with the inner
ring, the torque and speed limitations are virtually unaffected
and the performance of the bearing is almost identical to that
of an open bearing. Standard material is 300 series stainless
steel. Plastic fixed shields are also available on a limited
basis. Most Dynaroll shielded bearings have metal Z type shields. |
Double Shield - Code ZZ |
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| ZS TYPE SHIELD
The ZS shield is identical to the fixed
Z type shield, except that it is retained by an external snap
wire that locates in a groove inside the rim of the bearing outer
race. This is only an advantage if the user needs to remove the
shield after manufacture of the bearing. |
Double Shield - Code ZZS |
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| TS TYPE SEAL
The TS type seal is made from glass-reinforced
teflon. It is retained by an external snap wire to the bearing
outer ring, but also lightly contacts the inner race land. This
gives a high degree of protection from contamination, with a modest
increase in torque. |
Double Seal - Code TTS |
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D TYPE SEAL The D type seal consists of a molded Buna-N rubber lip seal with a steel insert. This provides maximum protection to the bearing against outside contamination. However, the high pressure of the lip seal itself results in greatly increased torque and friction losses that can cause heat build-up in higher speed applications. The seal material itself is rated to a maximum of 250 |
Double Seal - Code DD |
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