Online rolling bearing friction calculator helps
make power transmission systems more energy efficient

Schaeffler's new version of its rolling bearing calculation and simulation software, BEARINX^Ò, includes new functionality for calculating friction.

Used early in the design process, BEARINX^Ò-online Easy Friction helps users to identify and maximise the potential for energy efficiency savings within a machine or system. For example, after using the software, the user may decide to specify rolling bearings with reduced friction characteristics, or to downsize the bearings and/or other related system components.

Available online and free-of-charge to users and customers, the new BEARINX^Ò-online Easy Friction software module enables users to calculate the energy efficiency of different rolling bearing designs in any application. Users can pre-register now at http://BEARINX-online-easy-friction.schaeffler.com. Users will then receive an email notification as soon as the software module becomes available. Users will be able to conduct online calculations as of mid-2011 after initial registration.

BEARINX^Ò-online Easy Friction takes into account the internal load distribution of the bearing and contact pressures on the raceways and ribs, with the actual rolling element profiles. The new software module utilises a friction calculation theory based on physical algorithms confirmed by a series of comprehensive values from tests on rolling bearings. Bearing life is calculated according to ISO/TS 16281.

The software's intuitive menu structure and navigational tools enable users to enter data quickly and easily for bearing modeling, bearing selection and operating conditions. The bearing design for an elastic shaft system, for example, can either be modeled with a locating/ non-locating bearing arrangement or as an adjusted bearing arrangement. The geometrical data of INA and FAG rolling bearings is uploaded automatically from an integral database. The user enters the operating data such as the loads on the shaft system, shaft speed, the internal clearance and axial preload of the rolling bearings. Lubrication and cleanliness details can also be specified.

In addition, users can exchange any saved files with Schaeffler's 'Engineering Service' department in order to produce an optimum bearing design. Powerful servers at Schaeffler then perform the actual bearing calculations. The most important results are displayed in a results window, with the input data and calculation results documented in a PDF file.

Calculating friction with BEARINX®
Up to now, there were basically two methods of calculating the friction of rolling bearings - the catalogue method or by using special, multi-body simulation (MBS) programmes. The catalogue method uses an empirical approach, which enables calculations to be performed quickly using low model accuracy. MBS programmes, however, offer very high model accuracy but require longer calculation times.

Schaeffler's new method, which is based on physical bearing attributes, offers both fast calculation times and high model accuracy. The software considers a wide variety of influencing factors such as actual stress distribution and the internal geometry of the bearing. As well as load distribution and rating life, the software also enables users to calculate the frictional torque of rolling bearings and therefore the power loss of entire shafts or power transmission systems. This means it is possible to select a bearing concept with optimised friction characteristics early in the product development phase.

The new friction calculation module takes into account both rolling and sliding friction, in solid body, mixed and fluid friction cases. Elasto-hydrodynamic theory (EHD) is at the core of friction calculations. This deals with the formation of a lubricant film in the contact points of bodies under high loads when rolling at high speeds. EHD theory includes the formation of a hydrodynamic lubricant film and elastic deformation of the contact bodies. Every single contact in the bearing is analysed, since stress, sliding speed, viscosity and temperature are not constant over the contact surface of a body. All frictional forces on the discreet points of the contact surface are then available in the calculation results.

:The Schaeffler Group in profile
The Schaeffler Group with its product brands INA, LuK and FAG is a leading manufacturer of rolling bearings and linear products as well as a renowned supplier to the automotive industry of high-precision products and systems for engines, transmissions and chassis applications. The group of companies stands for exceptional customer focus, innovative ability and the highest possible level of quality. Sales of over 9.5 billion euros were generated at over 180 locations in more than 50 countries in 2010. With around 70,000 employees worldwide, the Schaeffler Group is one of the largest German and European industrial companies in family ownership.

For further information, e-mail: info.uk@schaeffler .com or view website: www.schaeffler.co.uk   Refer to page 17

Impress expands mechanical pressure
switches to include high pressure series

Instrumentation specialist Impress Sensors & Systems Ltd has expanded its SQ range of mechanical pressure switches to include a high pressure series, which is adjustable between 50 and 100 bar.

The new SQ high range mechanical gauge pressure switches are available in three versions: the cost effective SQ275-RH1 zinc-plated SPDT (single pole, double throw) pressure switch; the SQ276-RH1 stainless steel SPDT version for media compatibility; and the SQ27U-RH1 brass SPDT pressure switch. All three switches are user-adjustable between 50 and 100 bar.

The switches are a cost effective, robust option for OEMS and end users across a diverse range of process control applications, including pressure control for piping systems, lubrication systems, hydraulics and pneumatics, air compressors, hydraulic detection for fire fighting systems, sprinkler systems, medical equipment, and tyre manufacturing.

The SQ range of mechanical pressure switches from Impress Sensors also includes a medium pressure series. With similar technical features to the high pressure range, these switches are available in zinc-plated, brass and stainless steel housings, with adjustable pressure ranges between 20 and 49 bar.

The SQ high range pressure switches have NBR diaphragms as standard, with Viton and EPDM diaphragms available as options. Electrical connection is made by simple spade terminals and the switches have a G1/4" male process connection.

The switches can operate in temperatures from -10 deg C to +100 deg C. Response frequency is 2Hz and accuracy is +/- 5% FS.

Sam Drury, Sales & Marketing Director at Impress Sensors & Systems Ltd comments: "By introducing the high range SQ switches into our existing range of mechanical pressure switches, we can now offer customers robust, user-adjustable pressure switches from 5mbar up to 100 bar. Different housing materials, diaphragms and selectable contacts, allows us to cater for every customer's needs, from harsh, media compatible environments through to simple low cost mechanical switches for non-process critical applications."

Impress Sensors & Systems Ltd in profile
Impress Sensors & Systems Ltd  is a rapidly expanding UK manufacturer and distributor of instrumentation products based in Aldermaston, Berkshire. The company prides itself on its expertise in pressure measurement and its knowledge of general instrumentation. The company manufactures its own range of standard and custom-designed pressure instruments in the UK, and distributes a wide portfolio of instrumentation products from its European partners - BD Sensors in Germany and Metallux in Switzerland. Impress specialises in offering a customised service in applications where standard products may not satisfy the technical requirements and price aspirations of customers. The company boasts the necessary technical expertise in mechanical, electronic and application engineering that enables it to supply instruments tailored to the customer's requirements.

For further information, view website: www.impress-sensors.co.uk  Refer to page 74

Meggitt Sensing Systems introduces Endevco
piezoresistive accelerometers for legislative and safety testing

Meggitt Sensing Systems, a Meggitt group division, has introduced the Endevco® model 7264C series, a low-mass piezoresistive shock accelerometer family. Featuring a frequency response extending down to DC (steady state), the series is expressly designed to measure the long duration transient shocks associated with automotive crash testing, anthropomorphic device testing (ATDs), aircraft and automotive seat belt testing and other legislative and safety applications in which minimal mass loading and a broad frequency response are absolute requirements.

The patented Endevco® model 7264C series meets both SAE J211 impact testing and SAE J2570 anthropomorphic testing standards and features an advanced monolithic MEMS sensor design with integral mechanical stops for ruggedness, stability and reliability (US patents 4,498,229 and 4,605,919), incorporating a full bridge circuit with fixed resistors for shunt calibration. The MEMS sensors are manufactured at Meggitt's ISO9001 certified facility in Sunnyvale, California, USA, for consistently high-quality product, tested according to rigorous in-house standards.  

Featuring a small footprint and with a total weight of just 1.4 grams, the series is available in two versions: a 2,000 g model, with minimum 300 mV full-scale output and a frequency response from 0 to 5,000 g; and a 500 g model, with 200 mV minimum full-scale output and a frequency response from 0 to 3,000 g (±500 g). The series is also optionally available with <1% transverse sensitivity ("T" option) and <±25 mV zero measurand output ("Z" option).  Units are undamped for minimal phase shift over the useful frequency range. They also feature integral protection against electrostatic discharge (ESD) for the reduction of handling errors.  In addition, multiple calibration and connector variations are available. Please contact the factory for details.

Triaxial measurement capabilities may be achieved via the optional model 7953A triaxial mounting block or use of an alternative accelerometer product, the Endevco® model 7268C. Other recommended accessories for the model 7264C series include the model 126 three-channel DC bridge amplifier; the model 136 three-channel signal conditioner; and the model 436 DC differential voltage amplifier. Select models of the 7264C series are also available for immediate customer shipment under Meggitt's Endevco® Guaranteed InStock™ program.

For detailed specifications, drawings or additional information, view website: www.meggittsensingsystems.com  Refer to next page

Meggitt Sensing Systems
expands Endevco® Guaranteed InStock™
piezoresistive pressure transducer offerings

Meggitt Sensing Systems, a Meggitt group division, has expanded its Guaranteed InStock™ program to now include 19 Endevco® high-sensitivity piezoresistive pressure transducer models, with more than 400 units available for immediate shipment. 

All of Meggitt's Endevco® piezoresistive pressure transducers feature a four-arm strain gage bridge design, implanted into a MEMS diaphragm, for wideband frequency response and twice the sensitivity of traditional flat diaphragms for improved resolution. They are also shipped in special electrostatic discharge (ESD) packaging for added protection during shipment and handling. Available series models include:

1) Endevco® model 8510C series rugged, miniature, high-sensitivity, high resonance gage piezoresistive pressure transducers. Offered in ranges of 15, 50 and 100 psig with 225 mV full scale output, the series offers high output within a very small (3.86 mm diameter face) and lightweight (2.3 grams) package with excellent non-linearity of <1% to 3x over-range with 4X minimum burst pressure and 20,000 g shock resistance. Integral hybrid temperature compensation provides stable performance over a range of -18°C to +93°C (0°F to +200°F). Models also come standard with a vent tube that can be connected to any standard reference manifold for differential pressure measurements, or referenced to the ambient atmosphere. Typical applications include process control, blast testing, automotive airbag testing, rocket motor analysis, jet engine inlet pressure measurements, transmission testing and hydraulics measurements…../Continued on the next page