With their combination of electric motor and pneumatics, the new SRU Masterdrive rotary actuators from Schunk demonstrate what progress really means, being faster, stronger and more versatile.
The high dynamics and rapid response characteristics of an electric motor are combined with the power density and strength of a pneumatic drive to create a power pack that is both fast and strong. The effect of this idea is simple and convincing: less than 20ms after receiving the rotation signal from the memory-programmable controls (MPC), the integrated electric motor begins to turn the pinion. The pneumatics, somewhat slower to respond but, in turn, all the more powerful, then take a flying start and accelerate the movement.
On reaching half the rotation angle, the motor first starts to brake, followed by the pneumatics acting as a turbo-brake. Shortly before reaching the end-position, the pneumatics then leave the exact final positioning to the electronics and the motor.
The matched performance characteristics of the two drives therefore reduce the rotation times to a minimum and, at the same time, increase the possible payloads. This can be used either to reduce the rotation time to around 50 per cent of the previous time, or double the possible payload to 200 per cent. The positioning accuracy is less than 0.1degree.
Schunk's new SRU-MD rotary actuator also offers further benefits. Thanks to the combined drive concept, any required intermediate positions can be set. Up to three are already provided in the standard configuration, offering increased production flexibility.
The actuation of the SRU Masterdrive is very simple. The SRU communication electronics are installed in the control board, and can be addressed digitally via the terminals - in the same way as a pneumatic valve. Simply provide +24 volt to the terminal for the left end position, and the SRU moves to the left end position. The SRU communication electronics are connected to the SRU Masterdrive by a single communication and power cable, and requires only one pneumatic connection as the air supply. The pneumatic valves are already integrated, just like the sensors, so that no additional components are required.
The SRU Masterdrive is available immediately in the form of the SRU-40.1-MD; the 25 and 60 sizes will follow shortly.