BEARINGS, SEALS & GASKETS PRODUCTS BEARING SIMULATION SOFTWARE
Over their life, bearings can suffer from problems such as misalignment, reverse loading, false brinelling, overheating, contamination and lubrication failure. Failure, however, can be difficult to predict – for example, a bearing used in a robotic application may outlive the equipment it is installed in, but the same bearing
used in the same robot, in a high temperature application, could fail due to unsuited lubrication. However, around 90% of bearings outlive the equipment in which they are installed, and only 0.5% of bearings are replaced due to damage or failure. Simulation software can be used to help predict and counteract
this small percentage of failures. Using this, bearing performance, life and reliability can be extended beyond what was achieved a decade ago without the need for laboratory or field tests. Analysis gives unrivalled insight into bearing performance, enabling optimal bearing selection and avoiding premature bearing failure. The software is useful in the bearing sizing and selection stage
as well as for identifying potential equipment problems. For example, if an increase in heat or vibration was detected within a machine, bearing software analysis could be used to identify how the components in the bearing were moving in response. Complex software can allow engineers to build and simulate
models with motors, gear, shafts, housings and bearings. Advanced fatigue life methods can allow the accurate prediction of element and raceway stresses, rib contact, edge stress, and contact truncation. They also allow full system deflection, load analysis and bearing misalignment analysis. This will give engineers the information to modify the bearing design. Simulation software can also reduce the amount of time and
resources spent on the testing phase, speeding up development and reducing expense.
SMB Bearings
www.smbbearings.com
MINI BEARINGS FOR DENTAL EQUIPMENT Miniature rolling bearings (with an outer diameter of 6.35-7mm) used in dental air
turbines need to withstand rotation at speeds of up to 500,000rpm, while being quiet in operation and hygienic. Driven pneumatically by a turbine wheel, the two bearings in the head of the instrument ensure stable guidance of the drill during dental procedures. NSK’s bearings meet the demands. Among the materials used to make the bearings
is ES1, a special stainless steel developed by NSK that provides significantly increased purity and corrosion resistance compared with the commonly selected AISI 440C (equivalent to ISO 1.4125), the company explains. The high purity of ES1 stainless steel has a positive effect on bearing service life. It also increases corrosion resistance. The rolling elements are made of high-
performance ceramics, while the cage material is either PEEK or Torlon PAI. NSK also offers dental bearings in the highest accuracy class ABEC9 (P2) while attaining a bore diameter sorted tolerance class from 0.0025 to 0.00125mm, and from 0.00125 to 0mm.
NSK
www.nskeurope.com/en HYGIENIC GASKET SEALING PROFILES
Available from EMKA, Gasket Sealing Profiles for enclosures and other purposes are available in many thicknesses and widths of self-adhesive closed cell EPDM or Chloroprene rubber (CR) backed with non-stretch self-adhesive tape. Of benefit, the company’s self-adhesive gaskets have recently received certification to hygiene standard VDI 6022. These are suitable for specialist vehicles and
electrical/electronic cabinets, as well as street furniture with standard stock dimensions available from 30mm width to 80mm, and from 5mm depth to 40mm in coils or strips dependent on thickness. Solutions for custom applications are available.
EMKA
www.emka.com 70 YEARS OF CAGE-GUIDED NEEDLE ROLLER BEARINGS
Dr.-Ing. E.h. Georg Schaeffler revolutionised bearing technology 70 years ago with his idea to improve guidance of the needles in the needle roller bearing by using a cage. The first practical tests involving cage-guided needle roller bearings began in February 1950, with the components exhibiting extremely low wear and friction. A patent was applied for in September 1950 and one year later, after construction of a prototype, the first volume production orders were obtained from automotive manufacturers. Use in industrial applications was soon to follow. The new solution eliminated the serious disadvantages
associated with the full complement needle roller bearings that had previously been used as standard – the long needle rollers tended to move in a transverse direction during rotation of the bearing (skewing), which would then cause the bearing to jam. Furthermore, a substantial amount of sliding friction was generated between the counter-rotating needle rollers. In addition, the new solution enabled considerably higher speeds and less friction. This enabled engineers to substitute other bearing designs for cage-guided needle roller bearings and significantly improve the performance of their applications. In particular, needle roller bearings made an invaluable contribution to the
development of small, high-performance, and affordable vehicles. “Without reliable needle roller bearings, modern automotive drives would still be inconceivable today,” says Matthias Zink, CEO Automotive Technologies at Schaeffler. The use of needle roller bearings in mechanical and plant engineering, construction and agricultural machinery, and in conveyor technology, was also being gradually introduced. In the future, needle roller bearings will continue to play a key role. For
/ DESIGNSOLUTIONS
example, in e-mobility, they are vital for the function of numerous electrified transmissions. Needle roller and cage assemblies facilitate bearing arrangements with a minimal design envelope, since their section height only corresponds to the diameter of the needle rollers. In addition, they have a high load carrying capacity and are inexpensive compared with other bearing designs. KZK needle roller bearings (crank pin cages) are used, for example, in e-axles with a coaxial design. One application example is the Schaeffler e-axle drive, which has been produced for the Audi e-tron since 2018. In industry, where lightweight robots are increasingly in
demand, needle bearings permit light and compact joint designs by means of downsizing; and provide minimal variability and high levels of safety. The most recent example is the angular contact needle roller bearing XZU from Schaeffler, which is used both as an articulated arm bearing in lightweight robots and cobots, and as the main bearing arrangement in the new RTWH precision gearbox, a ready-to-install reduction gear unit for robot joints.
Compared to a machined needle roller bearing from the 1950s, the
operating life for bearings with the same dimensions has increased 15-fold, and the static load carrying capacity has tripled. The power density, which has been enormously improved thanks to the needle roller and cage assembly, offers considerable downsizing potential for applications that are easier on energy and resources. Today, the Schaeffler needle roller bearing portfolio comprises more
than 15,000 variants to fulfill a wide variety of requirements. Schaeffler
www.schaeffler.co.uk DESIGN SOLUTIONS | DECEMBER/JANUARY 2021 35
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