New from Techdrives, a division of Lenze Ltd, are high-speed electric linear actuators with output speeds of up to 635mm/s. Electrical operation gives a controllable alternative to hydraulics and pneumatics, without leakage problems, and with simple integration within machine systems. Options are AC, DC and servo motors, and strokes are available in increments of 100mm from 100-800mm.
These high-speed actuators are manufactured by linear motion specialist Servomech. Construction is in a 'U' configuration in which the motor is connected to a ball screw by a timing belt and pulleys. The pitch of the ball screw allows different rated speeds to be offered. Encoders for precise control of speed and position can easily be added either to the actuator housing or the motor. The result is a compact design that is also efficient, with running efficiencies around 70 per cent.
There are five sizes in the UBA range of high-speed actuators. The smallest model fitted with a DC motor has been used as a door actuator delivering a force of 85N at 635mm/s from a 4A, 24V motor. The closed length for 100mm stroke is only 365mm. In the middle of the range a model UBA2 is used for diverting baggage on airport conveyors. A force of 1800N is produced at 110mm/s with a frequency of 1400 operations per hour. The largest model in the range, the UBA4, can achieve 3000N at 265mm/s powered by a 1.1kW AC motor.
As these UBA actuators are based on ball screws, the duty cycle can be anything up to 100 per cent. Motors can be AC or DC but, for the highest performance and control, servo motors can be used. With the highly dynamic forces and reversible ball screws, encoder feedback to a controller is normally necessary, together with brakes on the motors. Optimum selection and installation requires consideration of factors such as buckling loads and critical speeds. Lenze Engineers at Techdrives have the necessary experience and expertise to advise on machine designs.
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