User Report

Hannover Messe Hall 17, as B40

For the reduction of harmful emissions from diesel engines in the public transport particulate filters have proven themselves. Negative characteristics to remain relatively high noise level and usually Overpowering the buses for the pure city use. High fuel consumption and correspondingly high emissions are the result. This is where the hybrid drive concept of e-Traction, which is supported by thin-section bearings from Kaydon Rodriguez.

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E-Traction from Apeldoorn, the Netherlands has specialized in the development and prototyping of electric drives. It all began in 1981 than Arjan Heinen with his first company managed to double through optimization of energy consumption, the operating time of between two forklifts for charging. In a series of projects aim was to realize electric driverless transport systems between the long-term parking and the terminals of the Amsterdam airport. It Heinen became clear that almost 50% of the energy have been swallowed by the gearbox. The logical development step "The Wheel" was: The registered trademark for a wheel unit combines wheel and electric motor and thus does without gears. The Wheel also contains an electrical or mechanical steering, shock absorbers and height control.

Redundant power transmission

The great advantage of the Wheel is that absolutely no additional transmission is needed. While in conventional electric motors, the housing is arranged stationary, and the inner rotor rotates, the wheel unit operates according to the reverse principle: the inner part remains stationary while the housing is rotated, which is also the tire is mounted directly. In this case, the larger the diameter of the engine, the higher the torque produced. In addition, conventional powertrains need a mechanical differential that compensates the different path lengths in corners and prevents erasing one of the wheels. At The Wheel-based actuators eliminates even this mechanical component. The required speed is balancing hardware and software-controlled. The same electronic management system takes over the functions of traction control and an anti-lock braking system.

The brake is released electromagnetically, while the excess energy is fed back into the power batteries. Particularly in pure battery mode extends this function, the range of a vehicle considerably. This allows lighter batteries are used, which has a positive effect on the total weight of the vehicle.

Small engine, large power

On the basis of The Weel 2004 became known as "The Whisper" a new drive concept for diesel-electric city buses introduced. The actual drive is via one's Something in the two front wheels, which are fed from a battery pack. To compensate for the relatively low range of pure electric vehicles, the batteries are supplied from a power-optimized Volkswagen passenger car diesel engine with a downstream generator. The advantage of this solution is that the engine can be made much smaller than is the case with normal diesel buses. This reduces fuel consumption, exhaust and noise emissions drastically. So a average European consumes Citybus in conventional construction as 1 2 liters of diesel per km, a bus of e-Traction comes with this amount of fuel 6,3 miles. The use of lithium-ion batteries and an improved generator management, these buses even reach a range of 7,6 km / l. The pollutant emissions are reduced by about two thirds.

Lean Warehouse convinced

Initially six different drives were installed in two different body variations and tested. It contributed Kaydon thin-section bearing the Rodriguez GmbH, Eschweiler, an important contribution. In The Wheel bearings are standard with an internal diameter of 18 inches and a cross section of an inch using. They convinced the one due to the large inner diameter for the implementation of the drive. Secondly, the outer diameter due to the small cross-section could be as small as possible be maintained. It filled the lean warehouse technology all performance requirements. Finally, it gave Rodriguez a conservatively calculated life expectancy of about 7500 h

After the testing phase, the hybrid cars are from 2006 entered production numbers between 200 and 500 units per year in a row. If one with an average mileage of 90.000 km per year based on a realistic fuel savings of 30.000 liters per year per vehicle, this means a promising possibility of environmental impact. Proven in practice: Since July 2009 Whisper the third generation is in the public transport mobility.

Thin section bearings for exceptional environmental conditions

The thin-section bearing expertise of Rodriguez primarily where exceptional environmental conditions apply when standard bearings reach their limits. So "Reali Slim" thin-section bearings have been modified for specific applications, for example, the joints in the robotic arm of the Phoenix Mars Lander. The vehicle arrives on the red planet to collect samples used. With a complete set of ball bearings to keep the forces and vibrations when starting level and stand out despite its compact, lightweight design for high load capacities. The bearings have to withstand very high forces: Breaking the ice on the surface and digging up 50 cm depth requires a force of about 45 kg. The bearings are made of heat treated 440C stainless steel, which is in addition honed to achieve an exceptionally smooth surface and a better ride. A further heat treatment allows the use of extreme cold, the joints of the robot are designed for a temperature of up to-108 ° C. Accordingly, the bearing are greased with special lubricant with low outgassing, which in extreme cold is not too tough and not in the rarefied atmosphere evaporates.

A cross section for five sizes

The thin-section bearings are characterized by a very small cross section at large bore diameter. The cross-section is the same for all sizes of a series. For even greater demands on miniaturization, weight reduction and very compact design, the thin section bearing program at the "Ultra Slim" series with a cross section of only 2,5 x 3 mm was expanded, which also remains constant with increasing hole diameter.

Whether inch or metric, or Reali Slim Ultra Slim as hybrid or custom designed - the portfolio comprises more than 250 thin section bearing types. This provides the optimal application-specific storage solution for every need are available.

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