Schaeffler has expanded its range of automatic lubricators with two new systems that provide accurate, efficient lubrication of spindle bearings with either oil or grease
Fag concept precision grease and fag concept precision oil are compact lubrication systems developed specifically for spindle bearings. As these rolling bearings support high running speeds, the key points of focus in their development are the correct supply and removal of lubricant, lubricant quantity and heat dissipation from the lubricant itself.
High performance greases are available today that enable spindle bearings to be lubricated safely and economically over long periods of time, even when running at very high speeds. For this reason, the majority of main spindles are lubricated with grease. However, these bearings are normally sensitive to being over-lubricated, which means that solutions are required that supply the correct volume of grease to the correct location on the spindle. In addition, high performance greases tend to harden and separate under pressure. The relubrication facility must therefore take this into account.
Fag concept precision grease
Fag concept precision grease from Schaeffler is a lubrication system designed specifically to meet the demands of main spindles in machine tools with respect to the volume dispensed on each stroke. Grease-filled hoses are connected to the outlets and form the actual lubricant reservoir for relubrication. The cartridge contains only pressurised oil that is pumped into the hoses during lubrication. The grease and pressure medium are separated by a ball positioned in the hose. The system provides 0.025cm³ per stroke and supply line. The grease is under pressure only during the relubrication process in order to prevent the grease from separating in the relubrication unit.
Fag concept precision oil
If applications involve very high speeds (> 1.6 million mm/min), the typical solution is to use a pneumatic oil lubricator. The disadvantage of this lubrication method is the need for compressed air, which is both resource-hungry and expensive. Compressed air costs for relubricating just one motor spindle in a three-shift operation can be as high as £550 per year. Insufficiently filtered air or the formation of condensation due to inadequate drying can also lead to premature spindle failure.
To solve these problems, Fag concept precision oil from Schaeffler provides direct oil lubrication in extremely small doses without the need for compressed air as a carrier. The innovation here is in replacing compressed air as the medium for transporting the lubricant into the bearing with a damper/throttle element, which provides a virtually continuous feed rate to the bearing. The concept was tested with Weiss Spindeltechnologie GmbH in a prototype motor spindle and has since been proven in practice. A speed-dependent control option for the direct oil lubrication system offers further potential for optimisation.
For more information, please contact Schaeffler UK’s Communications & Marketing Department on info.uk@schaeffler.com
