1 A customer newsletter from Schaeffler Group Industrial s Production Machinery Business Unit Issue 2011/2012 CURRENT NEWS Performance scaled up The best performing rotary axes in the world Schaeffler highlights EMO Hannover 2011 Page 3 Riding pleasure Highly efficient FAG torque sensor bottom bracket bearings for e-bikes Page 3 Efficiency in motion added competence for textile machinery Page 8 Hall 2 / Booth C142 Higlights for machine tools in high swings The advantages of the RKI motor series in machine tools, and for powerful, high-speed rotary table axes in particular, are convincing at a single glance: Torque: increased by + 30 % Speeds: increased by % P mechanical: increased by a factor of 5 Total Cost of Ownership: reduced by up to 60 % Installation space: identical outside diameter Costs: same performance, same price The impetus came from the automotive industry. The RKI wheel hub motors and drives used in electric cars or hybrid solutions achieve a mechanical power of up to 400 kw. Thanks to the over 400 % increase in speeds and approx. 30 % higher torque compared to conventional torque motors, there are now additional applications opening up for the RKI series in the field of machine tools. The downsizing option is convincing and can be achieved without major changes in design: The use of RKI motors with the same power enables costs to be cut in conjunction with converters. When using the combination of RKI direct drive + new Schaeffler ZKLDF..B axial angular contact ball bearing, manufacturers of machine tools and associated subsystems now have the option to build the most powerful rotary table axes in the world. RKI A revolution in direct drive technology: Over the past 20 years, direct drives have developed from special motors into volume production products. Their technology has been optimized step by step. Today s commonly available motors have reached a technical level that is almost impossible to improve in big leaps. The achieved force (torque) intensity is now sufficient for the majority of applications. The only constraint worth mentioning is limited speeds resulting from eddy current losses in the motor. Whenever a magnet moves along a coil or current flows through a coil, the magnetic field will generate a current that counteracts the cause of its generation. In concrete terms this means that the iron parts of the motor heat up. This can be compared with eddy current brakes in streetcars. Kinetic energy is converted into heat. This represents additional RKI motor thermal stress for the motor. Roughly a magnitude of about 150 Hz can be assumed for conventional motors and between 300 and 700 Hz for high-speed systems. This value is calculated by multiplying the speeds per second (n) by the number of pole pairs (2p) in the motor ( f = n * 2p ). Fivefold mechanical power: With the optimization of the power generating systems, the mechanical power of the RKI has been increased fivefold compared with a standard RI motor. Torque (Nm) RKI with Zx winding RI with WL winding RKI with WL winding Speeds (rpm) Comparison torque over speeds: RI versus RKI with WL and Zx winding resp. Continued on Page 2
2 Issue 2011/2012 Page 2 Issue 2011/2012 Page 3 Editorial Performance scaled up added competence for machine tools EMO 2011 in Hannover is likely to be a special yardstick of what has really been achieved in the field of machine tools during the past years. After all, EMO 2009 was hallmarked by the economic crisis and many companies, including us, decided not to put in an appearance there. In hindsight we can say that this turbulent time highlighted our great internal makeup which was conducive to producing some very respectable product innovations and portfolio expansions in spite of everything. So our message Performance scaled up refers on one hand to the new bearing dimensions that have been added to our range of products. We have both extended the external format and increased our internal performance depth. On the other hand, Performance scaled up added competence for machine tools refers to the large number of innovative additional benefits, the understanding of the overall system and the application engineering proximity to you and all of these are all crucial for our joint success. We are delighted to be able to present to you in this issue and at EMO 2011 a wide range of new products on offer, including - the most powerful rotary axis in the world - high-performance bearing solutions for large-size machines - new bearings for main spindles thermally robust and suited for extremely high speeds - the new torque motor RKI, a revolution in direct drives - linear guidance solutions for heavyweights to name only a few. We hope you ll be able to pick up lots of useful impressions for your day-to-day work! Sincerely yours, Helmut Bode President, Production Machinery Assistance on demand ensures riding pleasure Highly efficient FAG torque sensor bottom bracket bearings for e-bikes For the first time, the total torque is determined from the sum of the pedal force from the left and right pedals. Correct detection of the rider s requirement for motor assistance depends on the riding situation and corresponding control of the power outputs. These are decisive factors for a positive riding experience on e-bikes. Besides the direction of rotation and speed, measurement of the exact torque produced by the rider during pedaling is a prerequisite for precisely determining the additional drive power required from the electric motor. This is controlled principally by the torque sensor system in the bottom bracket. The rider no longer needs to provide additional pedal power. developed FAG Generation C deep groove ball bearings, which have around 30 % less friction compared with previous models. Numerous components in the area of the shaft are also coated with Corrotect corrosion protection developed by Schaeffler. Performance scaled up Continued from Page 1 This was mainly achieved with the following two design measures: - Up to 30 % higher torque: While standard motors of series RI still feature surface magnets on the rotor, these can no longer be found in the new RKI design. The RKI rotor consists of a magnet system, in other words: a laminated steel package in which many magnets are embedded. This package concentrates the magnetic flux (B). Using this rotor, up to 30 % higher torque can be generated in the motor (stator + rotor) compared with conventional surface magnets. The Schaeffler Group will once again be offering training sessions in Schweinfurt related to the maintenance and servicing of main spindle bearings. These all-day sessions are made up of theoretical and hands-on units. During the theoretical part, participants are taught basic knowledge of bearing types, performance characteristics, machining tolerances, lubrication and the monitoring of super precision rolling bearings. The hands-on unit includes mounting exercises, the handling of - Up to 400 % higher speeds: In order to keep the countervoltage as low as possible, a special winding is used in RKI motors. A combination of this Z winding and a laminated rotor enables losses to be significantly reduced so that up to 400 % higher speeds can be achieved. Air gap speeds of 50 m/s are possible now. Gigantic performance and cost efficiencies: 60 % reduction in power losses, TCO dramatically reduced. Considering the heat dissipation of torque output, one will notice another significant improvement. A direct comparison is possible based on the motor constant Km (unit in Nm/ W) which stipulates that Half the Km constant results in fourfold losses. The direct comparison between the RI and RKI series shows that the power loss is up to 60 % lower for the same torque output. Less heat is generated. Consequently the cooling requirements are lower, which has a positive effect on total costs of ownership (TCO). measuring equipment and the assessment of rolling bearing damage. All participants will receive detailed training documents. On-site training sessions for main spindle bearings can also be scheduled any time with machine tool and spindle manufacturers, repair centers and rolling bearing distributors. Your contact partner: Karin Morgenroth Tel.: +49(9543) schaeffler.com Speeds doubled with the new rotary table bearings ZKLDF..B: The bearing units YRTS and ZKLDF, designed for screw-mounting, have proved their worth in the combined turningmilling operations in machining centers. However, there was a demand from the market for even higher speeds without compromising rigidity. The new axial angular contact ball bearings of series ZKLDF..B enable up to 100 % higher speeds to be achieved compared with the previous standard at the same price and despite grease lubrication! This speed capacity is the absolute top of the range performance in the market. When combined with the RKI motor, this enables not only optimal cutting speeds for smaller workpiece diameters but also completely new and simpler bearing design options: the main spindle function for screw mounting. The next spindle bearing training session will take place in Schweinfurt on: Sep. 8, 2011 Dec. 15, 2011 Feb. 9, 2012 Jun. 14, 2012 Sep. 20, 2012 Innovation boost: Technology leadership and trend setting. For the machine tool industry, this hand-in-hand development of direct drive technology and bearings means an enormous innovation boost and stability of costs at the same time. Moreover, it is a perfect example of the added competence of global players united under one umbrella: The Schaeffler Group, together with IDAM (INA Drives & Mechatronics) and its brands INA and FAG, have over 100 years of accumulated concentrated rolling bearing and motor expertise on board. The result: Performance scaled up! Training course for attendance and maintenance of maichine tools main spindle bearings Tip Register quickly! These training sessions are much sought after! The new FAG torque sensor bottom bracket bearing is used, for example in the new high-performance drive from Bosch. The drive characteristics can be programmed and matched to the type of bicycle in up to four levels eco, tour, sport and speed. A degree of assistance up to 250 % (speed) is available depending on the mode and assistance level. Like all bottom bracket units from FAG, the new torque sensor bottom bracket is characterized by its excellent smooth running characteristics. This has been facilitated by an optimized bearing arrangement and the use of the newly EMO highlights for direct drive technology IDAM s RKI motors make significant contribution to world s best performing rotary axis High-performance rotary direct drive series RKI INA Drives & Mechatronics GmbH & Co. ohg (IDAM) the Schaeffler Group s specialist for direct drive technology achieves over 30 % torque compared with conventional torque motors with its high-performance rotary direct drive series RKI. Speeds can be increased up to four times and the mechanical performance fivefold. At the same time, power losses are reduced by up to 60 %. This means less heat generation, improved energy efficiency and a significant cut in operating costs due to less cooling requirements. But the downsizing options are also convincing: With unchanged output, smaller motors can be used and the costs for the converter reduced. In combination with the new ZKLDF..B rotary table bearings with doubled limiting speeds, the fastest rotary axis in the world can be built. For the machine tool this represents a unique selling proposition in the market. The RKI series offers special benefits when used in turningmilling centers. Torque motors in segment design Segment motor Easier to install and lower costs. Torque motors in segment design from INA Drives & Mechatronics GmbH & Co. ohg (IDAM) offer a maximum in economic efficiency. The motors are very maintenance friendly in the large diameter range. Coil winding systems that are composed and installed in individual Newly developed FAG torque and speed sensor bottom bracket bearing for e-bikes motor housings represent the specific feature of a segment motor. Every motor housing/individual segment has its own cable connection and is connected to the other segments externally in terminal boxes. Initial mounting and servicing is especially easy. Heavy-duty hoisting equipment or special tools are not required thanks to the segment design of the primary and secondary parts: If service is required, every segment can be checked and replaced, if necessary. The principle motor functionality is maintained through the other segments. This means that a degree of emergency running is possible, which ensures high equipment availability. Moreover, the replacement of parts can be carried out with conventional mounting tools.
3 Issue 2011/2012 Page 4 Issue 2011/2012 Page 5 EMO highlights: Machine tool bearings Rotary table bearing ZKLDF..-B The speed doubler EMO highlights in linear technology INA Linear Technology: Components and systems for heavy-duty linear guides ZKLDF..-B Schaeffler Group Industrial has further optimized the internal design of its double row axial angular contact ball bearing ZKLDF..-B, cutting the frictional torque by half. As a result, the bearing s limiting speeds have doubled, without compromising its high accuracy and rigidity. Used in combination with the new speedincreased RKI torque motors from IDAM in particular, the ZKLDF opens up new opportunities in turning and milling operations that were impossible to achieve with standard components in the past. Further optimizations have gone into the bearing design in the wake of the conversion to Generation B. To facilitate relubrication, the new Generation B bearings feature an axial lubrication duct on the screw mounting surface in addition to their lubrication groove on the bearing circumference. In this way, the lubricant can be supplied reliably, independent of the selected fit. When it comes to motor spindles, Schaeffler Group Industrial is combining suitability for maximum speeds with high load carrying capacity and insensitivity to changing operating conditions. This is done thru the new high performance spindle bearing series RS and thermally robust cylindrical roller bearings of series TR. Bearing supports for direct drive motor YRTC YRTC A combination of high rigidity, precision and low frictional power for more productive and efficient machine tools. In the bore diameter range between 580 and 1,030 mm, Schaeffler Group has combined its well-known YRT and RTC series to form the new YRTC series which provides even better performance. It is the basis for extremely dynamic rotary axes for high-speed positioning and form milling using multi-axis simultaneous machining. Even operation with steady-state speeds, e.g. for temporary turning, is possible within the limitations of use. At the same time, the frictional power has been significantly reduced compared with conventional axial-radial cylindrical roller bearings. Due to the significant decrease in friction, there is a considerably higher proportion of the drive torque from the drive available for axis acceleration and machining. Both aspects are conducive to increasing the productivity. Moreover, the heat induced within the machine structure is reduced. As a consequence, the temperature-related changes in machine geometry spindles can be considerably simplified compared with conventional solutions. RS New high-performance series Robust and high Speeds : FAG s RS spindle bearings (Robust and high Speeds) are super precision angular contact ball bearings with large balls. They feature a nominal contact angle of are reduced and the machining accuracy rises. With cooled axes, the cooling power can be reduced analogous to the reduced frictional power, which means there is an additional benefit in the form of lower operating costs. ZKXDF on track for volume production High speeds and compact size for combined milling/turning applications with over 1 m table diameter. This product opens up the option of designing economical and highly efficient compact bearing supports for high-speed rotary tables. Currently size ZKXDF580 is being implemented with 580 mm bore diameter. The innovation is based on a double row axial angular contact ball bearing in an O-arrangement with bearing rings that are neither split nor interrupted by a plug in the raceway. Benefits of this design include: - Improved transferability of bearing running accuracy to the machine assembly due to single-piece bearing rings. - Higher rigidity due to reduced number of joints resulting from the use of singlepiece bearing rings. - More cost-effective adjacent structure: Since the bearing rings are axially offset, it is sufficient to have plane screw mounting surfaces. Depending on the rigidity requirements, ZKXDF bearings do not have to be supported across the entire bearing height by the shaft due to their single-piece bearing rings. 20 degrees and an internal design with optimized friction characteristics. These characteristics make RS spindle bearings robust against changes in radial clearance and combine the speed suitability of a smallball high-speed series with the sturdiness and load carrying capacity of bearings with balls with large cross-sections. Bearing supports with these new spindle bearings are less sensitive to operating and environmental influences and open up new design options for high-speed spindles with high machining forces. The bearings are offered with balls made from bearing steel. In addition, they are also available in a hybrid version and in open, sealed and DLR design for oil-air lubrication. ZKLF..Hybrid Reliable even in short stroke operation: The new hybrid axial angular contact ball bearings ZKLF..-HC now offer a reliable and economical solution with the ultimate in robustness. This applies even under the most adverse operating conditions, in particular lengthy, short stroke operation of ball screw drives. The higher purchasing costs compared with standard bearings pay for themselves within a very short time, since the bearings will not break down due to the dreaded false brinelling. ZKLF..Hybrid EMO highlights for main spindle bearing supports New design options for motor spindles The use of ceramic balls results in an increase in limiting speeds and a tripling of the grease life. The DIN working groups have decided to revoke the theoretical reduction in dynamic load ratings due to overwhelming results achieved in field operation. Now there is nothing in the way of these bearings being used as problem solvers for the replacement of steel bearings, or as a new standard for enhanced reliability in short stroke operation. TR Thermally Robust bearings for motor spindles: The new Thermally Robust FAG cylindrical roller bearing TR, for the first time, combines the security for the non-locating bearing function with suitability for high speeds and operation under temperature fluctuations. It features a radially elastic outer ring with standard dimensions that can compensate for distortions resulting from radial clearance. The bearing s very high speed capability has been achieved through the adoption of the high speed design and a PEEK cage with optimized friction characteristics guided on one side on the outer ring. The optimized lubricant distribution and a low temperature level during operation provide additional security for the non-locating bearing function. The Schaeffler Group offers a wide range of linear guidance systems and related accessories for the economical, high-quality machining and handling of heavy-duty workpieces. Flat cage guidance systems: INA flat cage guidance systems of series M/V represent a combination of high load carrying capacity with supreme precision. Their load carrying capacity results from a high number of load-bearing rolling elements in the load zone as well as from the possibility of further increasing the number of needle rollers due to longer cages. The trend of heavy-duty machines towards increased dynamics can be satisfied by means of an integral restricted cage guidance system. This system prevents cage creeping even under very high dynamics, which results in increased lifetime. Typical application examples of such guidance systems are press transfer systems that take over the precise and high-speed handling of heavy components in between the various press stages. Here the parts weigh up to 200 kg. The transfer arm has a feed length of 8,500 mm and the travel speed is 8 m/s. Linear roller bearings: Linear roller bearings of series RUS and PR, based on cylindrical rollers, offer load ratings of up to 840,000 N and thus provide a high degree of flexibility and freedom of design. Sealed at the end faces, these linear roller bearings run especially smoothly and quietly. The patented end piece geometry and lubrication voids have been redesigned and optimized for load entry and lubrication distribution. This has resulted in improved running behavior with optimum preload even under the highest loads. As for the RUS linear roller bearing series, the rolling elements are kept at a distance by spacers. In comparison, the PR series comprises full complement bearings that do not use plastics. This makes the PR linear roller bearing particularly suitable for high temperatures and high-speed applications. A classic field of application for recirculating roller bearings is the main guidance of presses where extremely high forces are encountered. Used with corresponding adapters, linear roller bearings can be integrated directly into the adjacent structure so that the highest possible performance capacity can be achieved in a minimum of space. A selection of possible axis configurations Monorail guidance systems: High load carrying capacity, robustness, high rigidity and precision as well as excellent sealing these are the most important features of the latest, fifth RUE..E generation. Unlike other manufacturers who use barrel-shaped rollers in their monorail guidance systems, RUE..E is based on cylindrical rollers with end profiling. The large contact area of the cylindrical roller results in extremely high load carrying capacity and rigidity, while the contact pressure is reduced. The pure line contact enables slippagefree rolling. RUE 100 E-L was added to the size range. A carriage of this size features a dynamic load rating of 1,490,000 N. Such guidance units are used for example in ring dressing facilities for large rolling bearings destined for wind turbine applications. During the machining of rings with a weight of up to 4 t and a diameter of 4,500 mm, the RUE 100 E-L must support forces of up to 2 meganewtons in tension. Recirculating roller bearing RUE Vibration damping: The Schaeffler Group has extended its range of damping accessories, making it available for its large, high load-capacity series. For example, damping carriages of series RUDS 100 are now available for RUE 100 E in lengths of 150, 300 and 450 mm. These damping carriages are positioned on the guideway between the carriages. They feature a defined gap between the guideway surface and the bottom of the carriage that is filled with unpressurized oil. The resulting squeeze film dampens vibration and improves the machining result. Hydrostatic monorail guidance system: Moreover, INA Linear Technology offers the fully hydrostatic HLE linear guidance system. This ready-to-fit, sealed system with integrated pressure regulation combines the functions of guidance and damping in the design space of a monorail guidance system. Thus it replaces the monorail guidance system and enables optimum damping behavior with correspondingly positive effects on machine performance. Monorail guidance system INA linear technology for multi-axis positioning systems handling and gantry robot systems from INA save time and money: The INA Linear Technology business unit now also offers multi-axis handling and gantry robot systems as ready-touse complete solutions. Tailored to the requirements of the application in question, the new multi-axis positioning systems are functionally reliable units consisting of perfectly matched components from a modular system. Upon customer request, this offer can include all services such as project planning, overall and detailed design, preassembly and final assembly of components, protection and operating systems, control and programming, transport and final assembly of machines, commissioning and servicing as well as maintenance (including remote maintenance). The user saves time and money. Handling and automation solutions of different types and performance classes of up to 30 m stroke (travel distance), with traverse speeds up to 10 m/s and moving masses up to 500 kg can be implemented. INA Linear Technology offers the following products and services: - A wide range of guidance systems and monorail guidance systems for different applications (track roller and shaft guidance systems, linear recirculating ball bearing and guideway assemblies), - Different drive systems such as toothed belt drives, ball screw drives or trapezoidal lead screws and linear motors, - Linear actuators with special functions such as telescopic linear actuators or clamping actuators, - Different actuator options equipped in line with performance requirements and motors, gearboxes, sensors and controllers matched to tasks, - A wide range of accessories for adapting linear actuators and multi-axis systems perfectly to operating conditions, such as fasteners and connectors, clutches or clutch housings. In addition to individual consultation through the Schaeffler field service engineers, customers can simply enter their data for requirements analysis, consultation, design and project planning in an online form available at
4 Issue 2011/2012 Page 6 Issue 2011/2012 Page 7 Bearing solutions for large-size machinery Supports for rotary tables in vertical turret lathes You can count on it! Schaeffler Group demonstrates concentrated calculation expertise with extended tools: Easy Solution The Schaeffler Group offers comprehensive application, production and service expertise for large-size machining centers, combined with a wide range of corresponding products. One-bearing solutions represent a good compromise in relation to performance, design effort and price for the majority of these applications. However, two- or three-bearing solutions are also frequently used as they enable design solutions that are selectively matched to the specific requirements of the machine tool in question. Now a detailed catalog (TPI 205) has been published in German, English and Chinese that can be ordered via www. schaeffler.com and is also directly available for download. 1-Lagerlösungen 2-Lagerlösungen 3-Lagerlösungen Lagerlösungen für Großmaschinen One-bearing solutions Two-bearing solutions Three-bearing solutions Bearing Solutions for Large Size Machinery The economical one-bearing solution: From a mechanical point of view, the use of one single bearing represents the simplest bearing arrangement. It supports forces and moments from all directions and permits convenient relubrication. Bearing units of series YRTS and ZKLDF for screw-mounting are used here, for example. They are available in bore One-bearing solution with crossed roller bearing for the rotary table of vertical turret lathes: This economical solution for the majority of standard applications represents a good compromise between performance, design effort and price. diameters of up to 460 mm and 725 mm respectively. For larger diameters, Schaeffler offers crossed roller bearings that were developed specifically for these applications. They are available with diameters ranging from mm to 2,100 mm. Optimum performance through multibearing solutions: If several bearings are used as rotary table support, then this offers the possibility for application-specific combinations. In principle, each of the bearings can be selected based on its load carrying capacity, rigidity and speed suitability. The main bearing, which takes the form of an axial bearing, is the heart in multi-bearing solutions. Its characteristics determine the machine s performance to a considerable degree. The following two design variants have proved especially effective: The two-bearing solution: consists of an axial bearing (axial deep groove ball bearing or axial cylindrical roller bearing) and an angular contact bearing (angular contact ball bearing or FAG SmartCheck Maximum performance in a small package; compact and easy to operate. Designed for maximum speed requirements with optimum price/performance ratio in rotary tables of vertical turning machines: Two-bearing solution with ball bearings. tapered roller bearing): Axial runout is determined by the axial bearing, and the radial runout by the angular contact bearing. As a rule, the axial bearing sets the speed limits due to its larger diameter. It is preloaded by the angular contact bearing in order to ensure defined kinematic conditions in the rolling contact in every conceivable load case. The three-bearing solution: consists of two axial bearings combined with a radial bearing: The larger axial bearing supports the main loads of the table plate and the tool, while the smaller axial bearing is used for axially preloading the bearing support and as the counteracting bearing to support tilting moments. Radial guidance is via the super precision radial cylindrical roller bearing. As a general rule it can be said that design variants with ball bearings can achieve higher speeds, while those with cylindrical roller bearings offer higher rigidity and load carrying capacity. Axial deep groove ball bearings achieve speed parameters of up to 460,000 mm. min -1 compared to 270,000 mm. min -1 for Offering maximum rigidity and load carrying capacities: Three-bearing solution with roller bearings. cylindrical roller bearings. The highest load ratings can be achieved with axial cylindrical roller bearings featuring diameters of up to 3,830 mm. The accuracies achievable with large bearing diameters are also impressive. Schaeffler Group Industrial s range of products is rounded off by a comprehensive range of services that represent high added value for the customer. This begins with our on site engineering service and continues right on through solidly-based bearing design using Schaeffler s calculation software Bearinx. This tool enables calculating the conditions under all load cases, from the complete system down to every single rolling contact. The service units from the Industrial Aftermarket support customers in mounting and initial operation. Last, but not least our competent technical advisory service regarding operation, lubrication and maintenance issues makes a contribution to reduced operating costs and maximize bearing life. If required, the Industrial Aftermarket unit also offers bearing reconditioning and helps to minimize downtime. Safety through vigilance: FAG SmartCheck The FAG SmartCheck is a new, innovative single-channel online system for the monitoring of machines and plants. It comes with a set of more than 20 predefined parameter templates for monitoring, for example, imbalance, alignment errors, rolling bearings and gearings. In view of its outstanding price/performance ratio, this highly efficient tool makes online monitoring extremely economical. The FAG SmartCheck makes a valuable contribution to operational reliability and reduced Life Cycle Cost (LCC) and Total Cost of Ownership (TCO). In addition to the standard parameters vibration and temperature, the system also records other operating parameters such as pressure or loads. This provides a broad basis of information which permits experts to make a very accurate assessment of a machine s condition. Both the number of sensors and the level of system integration can be adapted to the specific application. Rolling bearing design is one of the focal points in design support. The Schaeffler Group has been successfully using bearing selection and calculation programs for this purpose for over 30 years now. Examples include the bearing calculation software Bearinx and the electronic product catalog medias. Right on time for EMO 2011, there s a new feature on offer: Linear EasySolution Powerful calculation software for linear guidance systems and rolling bearings. The Schaeffler Group s INA Linear Technology business unit offers its customers a new online calculation module for monorail guidance systems free of charge and available on the Internet 24/7. Based on the Bearinx bearing calculation software developed by Schaeffler, Linear Easy Solution enables the user to calculate the basic rating life of a driven linear axis supported by rolling bearings. A user-friendly and selfexplanatory interface with transparent menu navigation manages all the neces- The Basics of Failure Analysis, Part 1 Start screen for the Linear Easy Solution calculation tool As part of our new section The Basics of Failure Analysis, in this issue we would like to introduce you to the classification of failure modes. In general, bearing damage can be classified according to two different points of view: Starting from the existing operating conditions, such as contamination or overload, on one hand and from the failure mechanisms on the other. The latter approach has been standardized in ISO Our explanations of failure analysis in this and the coming issues of added competence will be oriented on the standardized classification. In our first chapter, we will be dealing with the issue of rolling contact fatigue as the number one of the standardized failure mechanisms. It is founded on the calculation of the basic dynamic load rating. The corresponding DIN ISO 281 standard defines the term life as follows: Fatigue Fatigue is apparent through symptoms of material spalling on the bearing raceways and the rolling elements, also known as flaking (see picture). The root cause of fatigue is contaminants that are unavoidable in steels and mainly take the form of alloy components. These represent discontinuities in the grid structure of the steel and lead to local displacements in the structure and rehardening as a consequence. Starting from these rehardening zones (butterfly), microscopically small cracks develop. During continuing operation these grow towards the surface into fatigue fracture in the rolling direction. When the fracture reaches the surface, the material will spall in localized areas. The cause of this damage is due to local pressure in the material. This damage can be the natural end of a bearing s life, but it can also be an indication of partial overload due to tilting or stress. Action: The existing loads and operating times should be validated and, if necessary, the causes for elevated pressure should be identified and eliminated. sary data input. The most commonly used linear axis combinations in a drive, guideway and carriage arrangement are preconfigured. In addition, users have the option of freely selecting an axis combination with up to four guideways and 16 carriages. Linear Easy Solution models the actual load on the guidance Structure of failure mechanisms Fatigue Wear Corrosion Electro-erosion Plastic deformation Fracture Subsurface fatigue Surface fatigue Abrasive wear Adhesive wear Corrosion through humidity Friction corrosion Creeping currents Passage of electric current Overload Indentations Forced fracture Permanent fracture Heat crack elements taking account of the contact angle displacement, the non-linear deflection behavior of the rolling element contacts as well as the elastic guideway and the carriage. Calculation is based on the most up-to-date algorithms for the simulation of linear rolling bearings. All data inputs for calculation, such as the axis configuration, forces and load cases can be saved for further processing and optimization purposes. Thus INA Linear Technology offers quick and immediately available customer support and personal consulting services; all which emphasize the focus on customer support by Schaeffler s worldwide engineering service. GERMAN INDUSTRIAL STANDARD October Life: For an individual rolling bearing, the number of revolutions which one of the bearing rings (or washers) makes in relation to the other ring (or washer) before the first evidence of fatigue develops in the material of one of the rings (or washers) or rolling elements. The influence of wear, corrosion and electro-erosion on the bearing life is not dealt with in the International Standard: Fretting corrosion False brinelling Particle indentations Indentations resulting from improper handling
5 Issue 2011/2012 Page 8 Issue 2011/2012 Page 9 Efficiency in motion: added competence for textile machinery The Schaeffler Group at ITMA in Barcelona Waldrich Coburg, partner of Schaeffler Gear milling technology on WALDRICH COBURG machines Rolling bearings for textile Lubtect machinery An extensive range of precise, ready to install and maintenance ready rolling bearing solutions are available for the textile industry. From simple component to complete high-tech solutions, Schaeffler provides reliable and economical bearing supports for nearly all types of machines in the textile industry. These include: - Thread guidance rollers with integrated wear and corrosion-protection layer and optimized friction characteristics, - A wide variety of low friction and durable tape tension pulleys with reduced residual imbalance, - Easy-to-fit radial insert ball bearings and housing units for machines in spinning preparation and texturing machines, - Spindle neck bearings, rotor bearings, tape tension pulleys and guide rollers in spinning machines, - Damped friction spindles and precise compacting rollers with integrated pivot joint in texturing machines, - Shock resistant yoke and stud-type track rollers in the gearboxes of weaving machines, - Lubtect lubrication in difficult environments, - Full complement needle roller bearings with optimized operating clearance in the swivel type operation of knitting and weaving machines, - Narrow needle roller and ball bearings with high load-carrying capacity in dobby looms, - Cages with Triondur coating in needle felt machines, - Linear guidance systems in embroidery machines, cutting machines, handling equipment, textile printing machines and many other textile machines. Whether innovative, application-optimized system solutions or proven and continually refined standard products, they all bring about a considerable increase in machine power, whilst reducing costs at the same time in spinning preparation, thread production, creating Lubtect An anwendungsorientierte application-oriented Alternative alternative to grease zu fettgeschmierten lubrication of bearings Lagern Bearing Supports for Textile Machinery surfaces, finishes or in the manufacture of ready-to-wear clothing. The two competence publications, BTM and TMB, for textile machinery are available for direct download at: INA thread guidance rollers Lightweights for improved machine profitability: The new INA thread guidance roller is extremely lightweight and thus increases the dynamics of every texturing machine. Due to its significantly trimmed outer ring wall thickness, this roller accelerates much faster. The moment of inertia of this machine element has been reduced by 30 % compared with conventional solutions. Featuring a chromium coating, the outer ring surface is resistant to corrosion and wear. Its surface roughness is such that the filament drives the outer ring whilst being protected against damage. Improved machine profitability FAG tapered roller bearings X-life for higher efficiency in weaving machines: Lower friction and higher performance. FAG tapered roller bearings X-life feature up to 75 % lower frictional torque compared with standard products. Their dynamic load rating has been increased by 20 %, which results in up to 70 % longer basic life rating. This was achieved by optimizing their geometry, surfaces and materials as well as their dimensional and running accuracies. As a consequence, the operating temperature in the bearing was reduced, which means that, for example, the stress on the lubricant is now considerably lower. This results in INA thread guidance roller extended maintenance intervals and the tapered roller bearing operates at noticeably lower noise levels. In addition, the new premium tapered roller bearings offer significantly higher energy efficiency. This also opens up downsizing options, that brings in the wake not only reduced installation space requirements but also further benefits such as lower weight and energy costs. Moreover, FAG tapered roller bearings X-life make a contribution to lower operating costs in terms of Total Cost of Ownership (TCO) and they reduce expenses in conjunction with maintenance and repairs. In the textile machinery industry, FAG tapered roller bearings X-life are ideally suited, for use in weaving machine gearboxes, for instance. Needle roller bearings: More efficiency in spinning preparation thanks to downsizing and less friction. Earlier this year, Schaeffler Group Industrial launched two new INA needle roller bearing designs that can be used in typical needle roller applications such as combers, knitting machines and double rib looms: X-life solid needle roller bearing with the TWin Cage Hall 2 / Booth C142 The performance-enhanced X-life solid needle roller bearing -D (for downsizing): Here a newly developed, profiled steel cage, produced by optimized forming methods, enables an increase in load ratings by up to 25 % with unchanged bearing dimensions. This means that bearings installed in the same mounting space can be subjected to significantly higher loads. Alternatively, they open up new design options for downsizing. The friction-reduced machined X-life needle roller bearing with TWin cage: The new machined needle roller bearing with the TWin Cage made of plastic provides higher efficiency as a result of lower friction. Two individual short needle rollers are inserted next to each other in one cage pocket instead of the otherwise usual single long needle X-life solid needle roller bearing -D (for downsizing) roller. This completely new combination of cage and rolling elements reduces the friction by up to 25 % in comparison with conventional needle roller bearings. The resulting lower heat generation in the bearing leads to longer grease operating life and therefore longer lubrication intervals, and also to higher accuracy of the application. Extensive test series have shown that needle roller bearings with TWin Cage have a considerably increased operating life. Machine tool manufacturer WALDRICH COBURG, a company with a long-standing tradition, and the Schaeffler Group have maintained a close and very successful partnership for many decades now. Various WALDRICH machines incorporate, for instance, Schaeffler spindle bearings, large-size super precision bearings, linear guidance solutions and many more. Established back in 1920, machine tool manufacturer WALDRICH COBURG has been continually expanding and refining its product portfolio ever since. Today the company manufactures products such as gantry milling machines and vertical turning turret lathes as well as grinding and boring machines. Now the world leader in the machining of large parts is entering uncharted technological territory by adding gear milling technology to its range of machining equipment. One example is a highly automated and flexible production system for the complete machining of internally toothed ring gears, used mainly in the planetary gearboxes for wind turbines. This system is optimally tailored to these workpieces. Consisting of two MultiTurn machining centers, it achieves an extremely high level of productivity. The machines are connected with a pallet transport system. Each machine is equipped with a rotary table for turning and milling operations. Both machining centers offer turning, boring, milling and gear milling functions. Due to the reduced number of clamping processes and minimal auxiliary process times, the workpieces can be manufactured more quickly, precisely and cost-effectively. Maximum quality and productivity are in focus. For the machining of straight and angular internal gears with gear form milling tools, WALDRICH COBURG has developed a special gear milling head. This has a maximum output of 75 kw and a torque of 7,000 Nm. It automatically pivots to the correct position for the helix angle of the gear. Large gear rings, as used in iron ore mills for example, have diameters of 15 meters and more. At the moment, WALDRICH COBURG is processing orders for two machines for the complete machining of such parts. The two PowerTec Gantries feature integrated rotary tables. The first machine has a clearance width of 7.5 m and a rotary table diameter of 6.5 m. It is capable of machining ring gears up to 12 m in diameter. Gear rings larger than 6.5 m are fixed using a clamping star that carries the clamping devices. The second gantry has even larger dimensions. Featuring a clearance width of 13 m, its rotary table has a diameter of 8 m. It can machine ring gears of up to 17.5 m. The machine s clamping plate measures 10 x 20 m. In addition to standard milling heads, the machines feature a gear milling head developed specifically for this purpose. The advantages of gantry machines for gear ring production are obvious: - Complete machining (turning, boring, milling and gear milling), - No lower diameter limits for workpieces, - Machining of all kinds of workpieces possible, - Use of modern standard CNC machinery, also for extremely large gear rings, - Productivity and degree of automation to WALDRICH COBURG standards. In all machines, the gear milling head is picked up automatically. The Z-axis remains in the same position during the entire milling process. However, the vertical movement is done with the cross rail of the machine. The cross rail is hydrostatically guided along both machine columns, giving the whole system constant rigidity. The performance of the rotary table is particularly critical for the production of high-precision gears. Especially for its large machines, WALDRICH COBURG used its expertise in the field of mechanical systems and control engineering for large machine tools to optimize the driving unit, consisting of gear ring and drives. This is the only way to safely control the tremendous mass moments of inertia in the control system. The design of the rotary table drive with its extremely high mechanical rigidity was undertaken in cooperation with the Schaeffler Group using the Bearinx calculation software. The bearing concepts and products of the INA, FAG and IDAM brands have also been supplied by the Schaeffler Group. Headquarters of WALDRICH COBURG Gear milling head Spindle bearings in practice The Schaeffler compendium for students and design engineers Here you will find what you are looking for! Application knowhow from the technology leader - Comprehensive compendium for spindle bearing practice compiled for students and design engineers, - Guideline for the selection and design of spindle bearing supports for the design engineer, - Concentrated spindle bearing knowledge from over 100 years of rolling bearing history, - Far more than just a catalog, - Specific bearing stressing in machine tools: - Design guidelines for the spindle environment, - Profound information on bearing arrangement, lubrication, mounting, - Prevention and analysis of bearing damage in main spindles, - and much more. Spindle Bearings Theory, Design and Application
6 Issue 2011/2012 Page 10 Issue 2011/2012 Page 11 The most popular rolling elements in the world adidas and Schaeffler Group at Technical Meeting in Herzogenaurach Tried and tested in renewable energy applications Bearing solutions for solar, wind and water power plants This year s highlight in bearing supports and direct drive technology for machine tools was an all-round event in the true sense of the word: It is a well-known fact that the adidas Group has a good feel for balls, producing top-of-the-range rolling elements. This was illustrated in a fun way during the evening program on the occasion of the Schaeffler Group s Eighth Technical Meeting, held at the central adidas Event Center. However, the technical aspects also got their fair share of the limelight, namely when guest speaker Dipl.-Ing. Nürnberg from the adidas Group explained in his presentation the development of the World Championship ball Jabulani. But in addition to top grade footballs, there are other kinds of balls that come from Herzogenaurach too. The city is also renowned for being home to another global player who is on the ball, and also produces first-grade rolling elements, albeit in a different playing field. In this context, the latest relaunch of the leading rolling bearing forum offered a wide range of technical presentations from the segments of main spindles and feed spindles, rotary tables, linear axes and direct drive technology that all dealt with products having a bearing on efficiency. In view of the impressive accuracy of the adidas football, Helmut Bode, President of Production Machinery, launched a counterattack and described the extraordinary characteristics of Schaeffler rolling bearing balls. Having dribbled out the ingenious Jabulani here, it was time for the latest market and company figures. With his lecture Motor Series RKI High Speeds and High Torque, Dipl.- Ing. Marko Pfeiffer, Head of Distribution at IDAM, presented an initial insider outlook to this year s EMO highlight, the world s best performing rotary axis. Downsizing options enabling the same output in a smaller design space and offering enormous cost reduction potentials due to motor size adjustments and the elimination of converters etc. This surprised the participants and was met with great interest. This was raised once again when Dipl.-Ing. Robert Jung from Application Engineering Machine Tool Bearings introduced in his presentation Performance Increase in Bearing Supports for Precision Axes the new ZKLDF..B rotary table bearing generation a real speed doubler. Dipl.-Ing. Michael Heid, Head of Application Engineering Linear Technology, provided insights into proven and brand-new support services from the Schaeffler Group regarding the dimensioning and design of linear bearing supports. Rolling element training with a feel for the ball The dynamic calculation of the machine structure, as well as the type, place and effects of adaptive damping formed special highlights of his presentation Simulation of a Machine Tool. Damping, albeit the damping of main spindles was also the focus of a lecture given by Dr.-Ing. Martin Voll, Head of Application Engineering Spindle Bearings. The optimization of the dynamic spindle behavior as well as the approach in damping design raised many interested queries, and so did Dipl.-Ing. Christoph von Kress from Application Engineering Spindle Bearings with his key note address entitled What bearing for what spindle? He offered a practice-oriented overview of the main fields of application for specific bearings and bearing supports and brought into play the benefits of the new RS spindle bearings (Robust and high Speeds) under the motto RS Opens up New Possibilities. Added Value through Adaptation of King Pin Bearing Supports, a contribution by Dr.-Ing. Jörg-Oliver Hestermann, rounded off the meeting. It provided detailed information about the implementation of vertical rotary axes in machine tools, exemplified with existing bearing solutions, in particular in large-size rotary tables. On the eve of the meeting, nearly all conference participants had used the opportunity to take a look behind the scenes at the Schaeffler plant in Herzogenaurach. Handball was explicitly allowed in these practical workshops: 1. Production tour (Focus: precision forming); 2. Failure analysis (Rotary and linear bearings in machine tools); 3. Validation (From request for quote to delivery: Testing and calculation exemplified using rotary table bearings); Production of adidas world cup ball Jabulani 4. The new Schaeffler Surface Technology Center (added competence for coatings as a design element). The contributions lead to a large number of informal personal contacts, an inspiring exchange in the forum and useful suggestions for the day-to-day business and beyond. The meeting was staged twice and both events were fully booked early on. The number of participants in these Technical Meetings is limited Technical Meeting 2011 deliberately in order to maintain the opportunity for mutual personal exchange of experience as well as the forum character of this exclusive event. The next meetings are scheduled to take place at the end of Until then it can be expected that the world s most popular rolling elements from Herzogenaurach will be key players in the game many times over. Schaeffler Group Industrial is systematically stepping up its activities in the field of regenerative energies. For more than 30 years now, the Schaeffler Group has been successfully positioned in the wind power sector and is an important development partner of all wind turbine and wind turbine gearbox manufacturers worldwide. In addition, the newly established Power Generation sector management handles all activities related to solar, wave and tidal power plants. It is also concerned with applications in classic water power (dams etc.) and conventional thermal power plants as well as with the transmission of energy. Thousands of hydraulic rod ends from Schaeffler Group Industrial have gone into the Andasol solar power plant. Here they support several hundreds of hydraulically adjustable parabolic troughs, positioning them with millimeter precision and helping them to continuously follow the sun. Solar energy: Bearings for precise sun tracking ensure higher efficiency. Schaeffler plain bearings installed in the Andasol solar power plant in Spain, for example, enable the precise swivel motion of the parabolic troughs and thus make a contribution to the plant s high efficiency. A total of 1,248 hydraulic rod ends are used here. They support the several hundred hydraulically adjustable parabolic troughs, position them with millimeter accuracy and enable them to continuously track the sun. Plain bearings are ideally suited for slow and precise swivel motions. They can support high forces and are suitable both for single-direction and alternating loads, e.g. resulting from changing wind directions. Thus the 150-meter collector chains can be aligned with the sun s daily path from east to west with a precision of tenths of a millimeter. Rolling bearings, for instance AXS angular contact roller bearings, are used for example in double-axis tracking systems of solar-thermal facilities such as solar towers and solar Stirling power plants. Mirror adjustment is a typical bearing application in these plants. Rolling bearing supports in the double-axis Sea waves as a source of regenerative energy: Schaeffler Group Industrial is a development partner for the Pelamis wave energy converter. The individual segments are connected using bearing units that are subject to constantly changing loads of up to several hundreds of tons. drive units enable the motion of the azimuth and elevation axes. High load carrying capacity and rigidity as well as high guidance accuracy are crucially important here too. These characteristics are the prerequisite for the reliable, smooth and low-vibration support of the solar mirrors. The bearings have to support high forces and torques caused, for example by gusts of wind. The bearing supports therefore play a decisive role in the plants reliability and economic viability. Hydropower: Bearings for wave power plants. In addition to solar energy, new forms of hydropower such as wave or tidal power plants will also make a considerable contribution to the energy supply of the future. The potential in wave power alone is many times higher than today s worldwide energy demand. About 15 percent of this demand could actually be covered through wave power plants, according to estimations by the World Energy Council. Schaeffler Group Industrial has been a strategic partner in one of the most promising projects of this kind right from day one, helping the British company Pelamis Wave Power to achieve a major breakthrough in the development of wave energy converters. Both being keen to leave a long term legacy of clean energy, two cooperation partners have made this progress possible by pushing the boundaries of bearing and seal technology and by thinking outside the box. In 2004, Pelamis Wave Power built the world s first offshore wave energy converter. Based on this experience, they have now developed the P2 design which is more efficient and cost effective than its predecessor. Comparable to a sea snake, the Pelamis wave energy converter floats on the surface of the water, firmly anchored to the sea bed. Gigantic steel tubes are hinged via joints and positioned transverse to the crests of the waves. Via hydraulic cylinders and pressure accumulators, the upward and downward motion of the waves drives hydraulic motors that are coupled with generators. The individual segments are linked with bearing units consisting of a combination of different Schaeffler bearings. Working forces on each of these joints can be up to several hundred tons, and these must be supported by the bearings. Plain or spherical roller bearings are used in dams in particular to enable the radial gates to be opened and closed. The picture shows the Benmore Dam in New Zealand. Conventional hydropower: From turbines to water screws. Schaeffler Group Industrial has also been excellently positioned in conventional water power generation for many years now. For example, plain bearings and spherical roller bearings are used in dams, in particular for opening and closing the radial gates. Bearings in such applications are subject to extreme loads since the water pressure and the weight of the lock act on them from a single direction. Nevertheless it must be possible to open the gates reliably and with low friction, even after With the Andasol power plants, the technology of solar-thermal power production celebrates its premiere in Europe. Andasol 1 is the largest parabolic trough power station worldwide. The climate-friendly 50-megawatt facility covers the power demand of some 200,000 people and saves about 150,000 tons of carbon dioxide. (Courtesy of: Solar Millennium) long times of disuse. Since the bearing positions are difficult to access, plain bearings are used that operate absolutely maintenance-free and rolling bearings are required to offer maintenance intervals of as long as possible. Bearing expertise is required also for the turbines used in water power generation, for example Kaplan or Francis turbines. This applies to the turbine rotor supports where, for example rolling bearings are used in smaller power packs. In addition, special plain bearings are used to support the turbine guide vanes that regulate the optimum water flow to the runner s vanes. But simpler applications in hydropower, such as water wheels and water screws, also require suitable bearing solutions. The bearings used here are manufactured from high nitrogen, corrosion-resistant steel (Cronidur 30), developed by the Schaeffler Group for such extreme demands. So they can operate directly in the medium without sealing, the water itself serving as the lubricant. Archimedes screw for water power generation on the Saale River: Rings and rolling bearings of the semi-locating bearing consist of Cronidur 30, a high-nitrogen, corrosion-resistant bearing steel.
7 Issue 2011/2012 Page 12 WIN!!! Yes, I would like to win a Blue Ray Player! Solution: LAST BUT NOT LEAST Win a trendy Blue Ray Player! Competition: Please complete our EMO slogan. Please enter the correct answer on the adjacent coupon. Complete the form and return it to: Schaeffler Technologies GmbH & Co. KG Production Machines division IEBSWE-SM Georg-Schaefer-Strasse 30 D Schweinfurt Fax: +49 (0) 97 21/ Closing date: May 31, 2012 There is no legal recourse. Employees of Schaeffler KG and trading partners are not permitted to take part. Preview of Issue 2012 The winner of our quiz in Issue 1/ EMO highlights in field operation 2. Innovations for printing machines 3. AMB in Stuttgart P added competence for machine tools Last name, first name: Company: Street/No.: City/postal code: Tel.: Fax: We would appreciate it if you would answer the following questions: Did we get your address right? Please let us know of any changes we need to make. (Please print letters) Who else in your company should receive added competence? What improvements would you like to see in the Production Machinery division? Dietmar Loh from the Engineering department at Klingelnberg GmbH in Hückeswagen is the lucky winner of an ipad2. The trendy high-tech device was presented to him by field service representative Jürgen Donath from Schaeffler s engineering office in Wuppertal in May. Data Matrix code ensures higher safety with spindle bearings Counterfeits are fake products that look very similar to original goods, so much so that it is hard to tell them apart by looks alone. They are manufactured with the goal of (unjustifiably) realizing the market price of the original. In addition to this fraudulent approach, the intent is often also to damage the image of a particular manufacturer. To protect high-grade Schaeffler products and their users against such machinations, FAG spindle bearings will in future be marked with an additional Data Matrix code. This will allow the immediate identification of every single super precision bearing. Applied both to the bearing and to the packaging, this 2-D bar code will show in the fraction of a second whether the scanned bearing really is the original FAG bearing as described in great detail. Alternatively it will immediately indicate that a second version of this product exists, in other words that this is a case of counterfeiting. Marking products with the Data Matrix code is part of Schaeffler s Group-wide STOP project (Security Technologies for Original Products in the Schaeffler Group). For Schaeffler business partners, this measure means considerably higher safety and security. +++ NEWSTICKER +++ NEWSTICKER +++ NEWSTICKER +++ NEWSTICKER +++ NEWSTICKER +++ NEWSTICKER You will find Schaeffler Group Industrial at ITMA in Barcelona (Sep , 2011 Hall 2, C142), at IMTS in Chicago (Sep , 2012) and once again at AMB in Stuttgart, Germany (Sep , 2012) +++ NEWSTICKER +++ NEWSTICKER +++ NEWSTICKER +++ NEWSTICKER +++ NEWSTICKER +++ NEWSTICKER Your local distributor: HOTLINE INA FAG The Barden Corporation Schaeffler Group USA Inc. Tel: Fax: Schaeffler Group USA Inc. Tel: Fax: USA Tel: Fax: U.K. Tel: +44(0) Fax: +44(0) Imprint Published by: Schaeffler Technologies GmbH & Co. KG Production Machinery division Editor in chief: Claudia Kaufhold Adress: Schaeffler Technologies GmbH & Co. KG IEBSWE-SM Georg-Schaefer-Strasse 30 D Schweinfurt Tel.: +49 (0)9721/ Fax: +49 (0)9721/ A Member of the Schaeffler Group Editorial team: Helmut Bode Rainer Eidloth Clemens Hesse Claudia Kaufhold Norfried Köhler Martin Schreiber Produced by: Buena la Vista AG, Würzburg