Crossed Roller Bearings
Published: 03/10/2003
The radar housing on the Royal navy’s new Type 45 Destroyer’s will rotate on Timken bearings. The radar – Samson – rotates at 30 revs/min on an innovative bearing setup which US-based The Timken Company assisted in developing
Author: Andrew Allcock
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Source;
Machinery
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AIA: New Stealth-Ship Radar Rotates on Bearings
November 1, 2003
The British Royal Navy uses a multifunction radar developed by Alenia Marconi Systems Ltd. Timken Co. crossed roller bearings are used in the turning base of the radar systems.
The British Royal Navy will be using Timken Co. (Canton, OH) crossed roller bearings in the turning base of the radar systems on its new Type 45 destroyer.
This new radar system is encased in a large, spherical housing atop the vessel's foremast. Inside the housing is a next-generation, multifunction radar developed by Alenia Marconi Systems Ltd. (AMS, Rome). The unit rotates at 30 rpm on a bearing setup that Timken helped develop.
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The bearings in the turning base have two sets of races and rollers brought together at right angles to each other. This crossed roller design increases the load-carrying capacity of the bearing, but keeps the bearing lightweight. Because the radar unit is located high above the waves, it was not only important to reduce total weight, but also to ensure durability. The bearings must also endure extreme temperature conditions, from polar winters to tropical summers.
Other design specifications of the bearing improve interaction with the radar's carbon fiber housing, and additional machining allows the bearing to function as an integral turning base for Sampson.
Special seals also were created to protect the bearing from the harsh environmental conditions.
In helping AMS to determine the optimal bearing configuration, Timken engineers used SYSx, a proprietary engineering software tool for calculating and predicting the performance of bearings, gears and housings used in a wide range of complex applications.
Source;
Assembly
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Technology you can use
By: DN Staff Automation & Motion Control Aerospace
September 13, 2004
Crossed-rollers strengthen largest naval radar bearing
The bearing of the rotating radar antenna atop the foremast of the Royal Navy's latest Daring Class destroyer must resist shock and overturn loads that would topple the unit and function reliably in a salt-spray environment.
Engineers at radar systems manufacturer Alenia Marconi Systems Ltd. selected a crossed-roller bearing designed in cooperation with The Timken Co. to support and turn the SAMPSON multi-function radar (shown below). At 3m in diameter, it is one-third larger than previous bearings of this type manufactured by Timken, says Tom Baker, chief engineer for process industries at Timken.
The crossed-roller configuration is essentially two sets of rollers in a common race. The rollers alternate with their axes at right angles to each other. This layout results in an overall bearing height that is marginally greater than that of a single bearing housing. But the load-carrying centers of each of the races (the point where the roller axes intersect the vertical axis through the center of the race) have a large "bearing spread," substantially taller than the physical depth of the bearing, which increases resistance to overturning moments.
Source;
DesignNews
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OOPS!!!
2012 D32-HMS-Daring-018 sampson bearing leak seaforces.org COPY (2).jpg
120306-N-ZI635-608 HMS Daring (D32) U.S. Navy photo by Mass Comms Spec Seaman George M. Bell 6th March 2012 wiki (2).jpg
In fairness; information relating to a refurbished (or replacement) bearing has been provided for one of the Type 45's - but that information was probably posted on the WNSF.