How can fuel consumption and CO2 emissions of a vehicle be reduced? KEB Automation has addressed this question and developed an individually tailored solution: a new high-performance clutch with special performance features.
One of the keys to reducing fuel consumption in vehicles lies in the deactivation of a compressor. This is precisely where KEB has focussed its efforts by developing an electromagnetic friction clutch, which is installed directly on the compressor. The clutch transmits a static torque of at least 50 Nm at a power of 35 watts and a rated current of 2.9A, achieving an operating speed of up to 20,000 revolutions per minute. With a maximum switchable differential speed of 11,000 revolutions, maximum slip times of 1,500 ms and a friction speed of up to 75 m/s, the electromagnetic clutch is characterised by its extremely high performance.
Challenging clutch development
The development of such a high-performance clutch solution, which involved working closely with a German car manufacturer, was a complex task, as Thorsten Nolte, Sales Engineer Brakes & Clutches at KEB Automation explains: “A particular challenge was the adaptation into the existing installation space of the compressor. The connection to the compressor shaft had to be designed as a mountable and demountable connection.”
“In addition, the overall length, weight and inertia had to be kept as low as possible – and cost-effectively. Furthermore, ensuring torque transmission, covering a temperature range of minus 40 degrees to 160 degrees Centigrade and creating a plug-and-play capability were aspects that had to be considered in the development process.”
After testing various types of connection to the compressor shaft, the right solution was finally found – a non-rotating, deviation-neutral clamping hub. There are two friction linings in the rotor. While the outer lining is used to transmit torque, the inner lining is used to adjust the working air gap during final assembly of the clutch unit. The preset working air gap is maintained until the vehicle is put into operation. The functioning of this process is patent-protected.
With a specially developed acoustic bonnet to reduce technical noise, the clutch also delivers a special highlight, as Nolte states: “Each clutch unit has successfully completed an entire run-in cycle and is ready for immediate use on the engine. We are pleased to be able to offer vehicle construction real added value in terms of consumption reduction with the new high-performance clutch.”