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Actuators offer power, size and accuracy

Edited by the Manufacturingtalk editorial team Oct 9, 2003

Actuators that offer high load capabilities in combination with micron accuracies use an interesting stepper motor design allied with a ballscrew and large bore bearings.

Oriental Motor, Japan's largest manufacturer of Stepper and AC motors, has launched a series of actuators that offers high load capabilities in combination with micron accuracies - performance that is made possible through the use of an interesting stepper motor design allied with a ballscrew and large bore bearings.

New to the company's LIMO range, the actuators first distinguishing feature is a specially designed stepper motor.

Operating in a conventional manner, the motor does however exhibit a hollow rotor that extends and expands beyond the envelope of the stator, creating an enclosure for a ball screw.

When the motor is energised, the rotor and the enclosed ball screw rotate causing a precision-ground threaded shaft to move in and out of the actuator body.

The extended rotor, encompassing the ball screw, is supported, within the actuator's outer body, by a pair of large-bore bearings.

The use of a 5-phase stepper motor, offering a 0.72deg step angle, in combination with a ball screw, results in some extremely accurate positioning figures over the unit's effective stroke length.

And, unusually for such precision devices, the actuator is capable of carrying significant loads thanks to the incorporation of the large bore bearings, which handle any thrust loads.

According to Mark Checkley at Oriental Motor: "There are similarly designed units available on the market but none that can offer the accuracy inherent with the use of a 5-phase stepper.

Tin can versions can be obtained but, with a 7deg step angle, they cannot touch the accuracy offered by the DRL." Extremely compact in design and using a minimal number of parts, the DRL series is available in three standard frame sizes: 28, 42 and 60mm.

Two types of actuator are available, a standard version and one with a guide.

In addition to these two versions, users are also offered an electromagnetic brake and/or an adjusting knob as two further options.

To complement the actuator users can also specify a mounting plate and a bespoke driver to complete the package.

Oriental Motor envisages a number of applications that would benefit from the size, functionality and capabilities of these actuators.

These include precision X-Y stages, microscope automation, semi conductor manufacture, medical dosing equipment, optical measurement systems and electronic manufacture, to name but a few.

The DRL series is the first example of a larger range of linear systems that will soon be available in the UK from Oriental Motor, expanding on the company's existing motor and fan ranges.