23 Jul 2024


Centrifugal lubrication boosts bearing speeds

Centrifugal lubrication boosts bearing speeds

To cope with the ever-increasing speed demands for machine tool applications, NSK has developed a pair of bearings designed to maximise cooling of the bearing at extremely high rotational speeds:

• The first, called Spinshot, uses a patented system that harnesses centrifugal force to boost the flow of oil into a bearing as its speed rises.

• The second, called RHP Ultra, caters for slightly less demanding applications, by optimising the design of all the bearing components.

Although oil jet lubrication has been used before at high speeds, the Spinshot lubrication system offers a less costly alternative based on an oil-air mixture and a simplified spindle structure. The system creates a centrifugal force, increasing the oil flow with speed, to achieve limiting speeds of up to 3.55 x 106 dmN under conditions of constant pressure preload.

The Spinshot system is designed to be used with NSK`s EX series of bearings, significantly raising their limiting speeds. An added environmental attraction of using a oil-air mixture is that it cuts oil consumption.

The Ultra system optimises the design of the bearing`s rings, cage and rolling elements to allows the use of grease lubricants at speeds previously regarded as too high for this form of lubrication. In steel ball versions, it achieves speeds that have previously only been possible using ceramic balls. A steel/ceramic hybrid version is available that allows a top speed 30% higher than the steel-balled model. To boost performance still further, the Ultra system can also use an oil-air lubrication system, allowing speeds as high as 2.8 x 106 dmN .