Release time : 2015-06-15 08:38:19
NTN Corporation (hereafter NTN) has developed a new jet lubrication system for use with single row cylindrical roller bearings mounted on machine tool spindles. The new Minimum Quantity and Cooling Jet (MQCJ) lubrication system enables the achievement very high rotational speeds in machine tool spindles.
In recent years many manufacturers have been increasing the speed of the main spindles in their machine tools to improve the processing efficiency and surface quality of the work piece. Current conventional jet lubrication designs use large amounts of lubricating oil (L/min) for both lubrication and cooling purposes. Large amounts of oil are forcibly fed into the bearing for reliable performance. Unfortunately the amount of oil needed for this system creates significant drag in the bearing resulting in large power losses to the main spindle. A larger drive motor is then required to overcome this power loss.
Four years ago, in an effort to address these problems NTN developed the MQCJ lubrication system. The MQCJ lubrication system directs most of the lubricating oil to the inner ring for cooling purposes. By controlling the geometry of the oil inlet nozzle and inner ring only the amount of oil needed to lubricate the bearing is supplied to the rolling elements. Two years later NTN successfully applied the MQCJ system to angular contact ball bearings.
When the new MQCJ lubrication systemwas applied to a single row cylindrical roller bearing the ultra high dmn value of 3.35 million1) was achieved. By applying the new MQCJ jet lubrication system to the cylindrical roller bearing found at the rear side of many main spindles power losses from the bearing can be cut in half and the design can be simplified when compared with the conventional jet lubrication.
The new MQCJ lubrication technology for ultra high-speed single row cylindrical roller bearings will be displayed at JIMTOF 2008 (Japan international machine tool exhibition) to be held at the Tokyo Big site from October 30th.
[ Features ]
a. One of the worlds fastest high-speed operations: Maximum 3.35 million dmn value, an improvement of 45% compared with conventional air oil lubrication. For example a bearing with a bore of 55 mm will have a maximum rotational speed of 45,000 rpm.
b. Power loss is reduced by 50% when compared with conventional jet lubrication
c. Simplified oil feed/drain system (Cooling oil for outer cylinder and lubrication oil for bearings are the same)
[ Applications ]
Ultra high-speed main spindles for machine tools, machining centers for die processing & aluminum processing