DÜSSELDORF, GERMANY (Nov. 20, 10:45 a.m. EST) — At K 2001, a new type of electric motor, shaped like a spinning doughnut, drew onlookers to the Siemens AG booth as it hypnotically spun then stopped, spun then stopped, moving a toggle clamp inside a glass case.
Siemens officials showed the circular motor to demonstrate an example of a direct motor driving the clamp. The unit does away with the need for the current status quo, belts to transfer the power, said Wolfgang Lienke, director of automation for plastics, rubber and cable machines at Siemens' automation and drives operation in Erlangen, Germany.
Normally, in current electric-press technology, the process works like a nut on a threaded bolt. Using a belt drive, power is transferred from the rotating servo-electric motor to the threaded shaft, causing the shaft to spin and moving a ballscrew — basically a nut with ball bearings inside — back and forth.
But on the new Siemens motor, the screw is fixed and does not move. A round electric motor actually encircles the nut, so when the motor spins, the nut — and not the bolt — takes the energy, in a direct-drive fashion.
According to Siemens, the direct transmission of torque increases the precision of the mechanism, and reduces maintenance since the drive is virtually free of wear.
At its K show booth, Siemens was touting its ability to design machine controllers — and electric drives — on a customer-by-customer basis, according to Len Wedig, business manager for plastics at Siemens Energy & Automation Inc., the U.S. controls operation in South Lebanon, Ohio.