The simplest of the many systems used to protect
bearings during operation is the application of commercially
available seals, whose rubber or similar material lips is
always in contact with the rotating shaft.
This system generates friction and cannot be used in high
speeds applications. Efficient labyrinth seals are important
in these cases. Their design varies according to available
space, lubricant type and operating environment.
The seals illustrated herein are commonly used in the machine
tool industry and are quite suitable for other applications
with similar operating conditions.
Figure 7
The bearing is protected by the barrier created by the cover,
with small clearance to the shaft. This solution, suitable
for moderately dusty environments, is not recommended for
liquid contaminants.
Figure 8
This is a slightly more complex but more efficient seal than
the former. It features a supplementary internal barrier consisting
of commercially available laminar rings that fit to the static
housing. Rubbing on the rotating parts must be avoided.
Figures 9 and 10
These single and multiple type labyrinth seals are more elaborate
than the previous ones but are more effective, especially
in the presence of dust or coolant jets, etc.
Figures 11 and 12
These single and multiple type labyrinth seals are
provided with drainage. The upper cover, showing Figure 12
(vertical axis), acts as a centrifugal ring and ensures additional
protection against debris from the outside.
Figure 13
This seal is very effective due to the presence of a pressure
air barrier (p = 0.2 bar) in the labyrinth space. In this
system, particularly suitable for grease lubrication, the
air must be supplied filtered and dried, through a specific
channel.
Oil lubricated bearings operate in a pressurized environment,
so sealing efficiency is less important than for grease lubricated
ones. All contamination should be avoided for oil lubricated
bearings especially when a re-circulation circuit is provided
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GRW
Product Desc.