Sealing solutions for machine tools spindles
Contaminants and moisture can negatively affect bearing service life and performance. This is particularly important for machine tool applications where coolant and swarf are an integral part of the operating environment. Therefore, an effective sealing arrangement is essential if a spindle is to operate reliably. To protect the bearings, GTI offers a wide assortment of external and integral seals.
For bearing arrangements where the effectiveness of the seal under specific operating conditions is more important than space considerations or cost, there are two types of external seals available: non-contact seals, and contact seals.
Non-contact seals are almost always used in high-speed precision applications. Their effectiveness depends, in principle, on the sealing action of the narrow gap between the shaft and housing. Because there is no contact, these seals generate almost no friction and do not, in practice, limit speeds, making them an excellent solution for machine tool applications.
Seal variants range from simple gap-type seals to multi-stage labyrinth seals. Compared to gap-type seals, multi-stage labyrinth seals are considerably more effective as their series of axially and radially intersecting components make it more difficult for contaminants and cutting fluid to enter the bearing.
In highly contaminated environments, a complex labyrinth seal design is often required. Labyrinth seals can have three or more stages to keep lubricant in and contaminants out of the bearing arrangement.
Contact seals are generally very reliable. Their effectiveness, however, depends on a number of factors. Friction between the seal lip and counterface can generate a significant amount of heat at higher speeds. As a result, these seals can only be used in lower speed spindles and/or in applications where the additional heat does not significantly affect spindle performance.
Sealed bearings are generally used for arrangements where a sufficiently effective external sealing solution cannot be provided for cost reasons or because of space limitations.
GTI supplies a wide assortment of super precision bearings fitted with a seal on each side. For details, refer to Sealing solutions in the relevant product section.