Spherical roller bearings improve efficiency and safety of marine drives

One of the world's largest luxury cruise liners is using special coated spherical roller bearings to help ensure the smooth, safe maneuvering of the ship, while also reducing vibration and noise levels, leading to reduced fuel consumption.

Luxury cruise liner 'Celebrity Solstice', which was put to sea for her maiden voyage at the end of 2008, uses drive technology that incorporates sophisticated bearing technology from precision bearings manufacturer The Schaeffler Group.

The ship's propulsion and steering drives utilise one FAG radial spherical roller bearing and two FAG spherical thrust roller bearings, which enable the liner to accelerate to a speed of 24 knots (45km/h). The bearings ensure that steering and precise deceleration manouvres are performed smoothly and safely. Special coatings on the bearings are critical to the efficient operation of the drives.

Worth almost half a billion euros, Celebrity Solstice is the largest ship ever constructed in Germany. The vessel measures 315m in length - the length of three football pitches. The ship accommodates around 2,900 passengers in 1,430 cabins and features an array of amenities, including a huge theatre, a casino and a real lawn for playing golf.
 
Propulsion and steering of the ship are combined in a freely rotating vertical pod outside of the hull. These so-called 'POD drives' provide extremely low vibration and noise levels during operation, therefore enhancing passenger comfort. The drives significantly improve the maneuverability, and therefore the safety, of the ship, as well as offering higher efficiencies, resulting in both lower fuel consumption and reduced emission levels. The power output per drive unit is 20MW.
 
Schaeffler's bearings support the drive shaft on the locating bearing side in each of the two engine pods, accommodating thrust forces and loads from the engine and propeller.

The large spherical thrust roller bearing, which has an outside diameter of 850mm, serves as the main thrust bearing and is subjected to thrust loads of up to 150 tonnes at maximum speeds of 135rpm. Under extreme conditions, the bearing can even support loads of up to 430 tonnes for short periods.

The smaller counter bearing, which is also an FAG spherical thrust roller bearing, has an outside diameter of 620mm. The bearing withstands reverse thrust loads during maneuvering operations. The bearing is designed for loads of up to 20 tonnes, although in extreme cases, it can withstand loads of up to 200 tonnes for short periods.

The FAG radial spherical roller bearing, also supplied by Schaeffler, is designed to accommodate radial loads from the engine, the weight of the propeller and dynamic forces. The bearings in the Schaeffler thrust block unit are arranged in such a way that they align via a common point and so are able to compensate for any misalignment of the drive shaft.
 
Low friction bearings provide greater efficiencies
Schaeffler's bearings play a pivotal role in improving the efficiency of the drive. In order to optimise bearing system kinematics and reduce friction, the outer ring of the radial spherical roller bearing and the housing washers of the spherical thrust roller bearings are coated with Durotect^® Z.

Developed by Schaeffler, this special coating reduces the coefficient of friction and adhesion properties, while increasing the bearing's resistance to corrosion and fretting. In addition, the outer diameter of the 7.5 tonne thrust block unit (flange connection) is equipped with a 14mm thick, synthetic compound coating, which offers excellent damping properties, as well as providing electrical insulation. This coating prevents the rolling contact zone from being damaged by leakage currents or downdraft. The coating provides reliable protection up to 15,000V.
 
The thrust block unit's bearing and oil bath are monitored using temperature sensors. The individual bearings are also fitted with a condition monitoring system that detects damage at an early stage, enabling maintenance tasks to be planned well in advance. This eliminates costly, unexpected bearing failures.

For further information on Schaeffler's range of spherical radial and spherical thrust roller bearings, view website: www.schaeffler.co.uk or telephone the marketing department on 0121 351 3833 and ask for a copy of HR1.

A range of tailor-made training courses for the fitting,
maintenance and condition monitoring of rolling bearings

A range of tailor-made, modular training courses for engineers on the fitting, lubrication, alignment and condition monitoring of rolling bearings, is now available in the UK.

The training courses, provided by Schaeffler (UK) Ltd, can be individually tailored for each customer and for all skill levels, including apprentices and more experienced engineers.

Training course units, which include bearing mounting and dismounting, lubrication, alignment, condition monitoring and maintenance management, are based on a modular concept, enabling customers to compile their own customised training course for staff. Training is carried out at Schaeffler's UK-based headquarters in Sutton Coldfield, West Midlands, or at the customer's own premises.

Bearing mounting and dismounting courses include training modules on rolling bearings, mounting tools, spindle bearings and more specific courses such as tapered roller bearing maintenance for rail vehicles.

Schaeffler also provides a range of vocational courses for apprentices on rolling bearing selection, the correct mounting and dismounting of rolling bearings, as well as teaching them about the lubrication of rotating components, alignment and vibration monitoring.

As Ian Pledger, F'IS Field Service Engineer at Schaeffler (UK) comments: "When it comes to bearing mounting training, there really is nothing as effective as the hands-on approach. While there is plenty of literature available on how to correctly mount rolling bearings, there is a general lack of physical components within UK companies with which apprentices can learn how to fit these bearings under realistic conditions. We provide customer-focused, on-site training if required."

In lubrication training courses, maintenance technicians are taught how to use Schaeffler's comprehensive range of bearing lubrication systems, including Motion Guard. Other lubrication modules include the use, applications and handling of Schaeffler's Arcanol range of bearing lubricants, where trainees will learn how to choose the appropriate grease for their particular application.

Alignment training includes courses on specific Schaeffler products such as the Smarty2 and Trummy2 for the tensioning of belts and for the alignment of belt drives and shafts to ensure higher performance and longer life of plant and machinery.

"Many inexperienced maintenance technicians are unsure how to correctly fit rolling bearings and are equally unaware of how susceptible these bearings can be to damage and excess wear if they are not fitted appropriately. Rather like DIY jobs at home, if you use the right tools, the task can be completed in half the time with half the effort. That's what we are trying to achieve in our rolling bearing courses," adds Pledger.

Schaeffler also offers training courses on the condition monitoring of rolling bearings. General vibration monitoring theory is covered, including specific product training on Schaeffler's popular FAG Detector III handheld vibration monitoring and balancing system. Other product-specific training modules are available for Schaeffler's fixed condition monitoring systems such as FAG DTECT X1 and FAG ProCheck.

For further information on Schaeffler's range of bearing and condition monitoring training courses, view website: www.fis-services.com   

Schaeffler confirms its strength in innovation

The Schaeffler Group is now ranked in the top ten most innovative companies in Germany, according to the latest patent registration figures released by the German Patent and Trade Mark Office.

Schaeffler KG, which includes the INA Group, FAG Group and LuK Group, now stands in eighth place in the rankings with a total of 605 patents granted in 2008, with LuK ranked 21st with 221 patents. This means that together, INA, FAG and LuK is currently the fifth most innovative company submitting patent applications in Germany. Together with its other group companies, including IDAM (INA Drives & Mechatronics), AFT, The Barden Corporation, FAG Industrial Services, etc.), the Schaeffler Group handed in more than 1,250 new patent applications in 2008, which represents an average of more than five patents per working day.

Dr. Peter Gutzmer, Member of the Schaeffler Group's Executive Management Board responsible for Technical Product Development and in charge of the Group's worldwide R&D activities, considers this strength in innovation to be one of the company's mainstays. "The Schaeffler Group's firmly entrenched roots in over 60 different industrial sectors give us the opportunity that hardly any other company has, to transfer our expertise and to introduce this into new solutions. Our customers in the automotive industry benefit from this and so do our customers in other industrial sectors," he pointed out.

Development efforts at Schaeffler focus on new developments aimed at more efficient use of resources. One of the latest examples is the company's fully variable 'MultiAir' valve train. Developed by the Schaeffler Group in collaboration with Fiat Powertrain, it was recently presented to the general public for the first time at the Geneva Motor Show. Compared with conventional motors, the result is up to 25 per cent lower fuel consumption and CO2 emissions, as well as enhanced driving dynamics.

With more than 1,250 patent applications annually and some 14,700 patents in force, the Schaeffler Group has always been a pioneer of industrial innovation. Some 5,200 employees in 30 development centres worldwide are working on new power transmission solutions for machines and vehicles. In the automotive field, the product range comprises components and systems for engines, transmissions and chassis applications, and the application spectrum in the industrial sector spans from wind turbines and production machinery through to medical equipment.

The German Patent and Trade Mark Office disclosed the number of patent applications for the year 2008 on March 16. For further information on the number of patent applications disclosed, view website: www.dpma.de

For further information on the Schaeffler Group, view website: www.schaeffler.co.uk   Refer to next page