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Segmented stator boosts actuator torque

An Inmoco product story

Edited by the Engineeringtalk editorial team Mar 25, 2002

A novel segmented stator design provides increased torque performance for an established range of integrated linear actuators.

The off-the-shelf convenience and flexibility of Inmoco's SR Series of integrated linear actuators is being complemented by increased torque performance, following the introduction to the range of new T-LAM segmented stator technology.

The T-LAM design enables 35% more continuous motor torque to be provided from the same frame sizes as existing SR series units, with no cost premium.

The improved torque performance (up to 9.31Nm) and efficiency of the SR Series units are the result of a design harnessing the combination of high-density Neodymium iron boron magnets and the limited heat generation qualities inherent in the new T-LAM segmented stator design.

In particular, the elimination of end turns in the stator, and the use of thermally conductive potting removes the parts most susceptible to failure in a traditional stator.

The design also benefits from interface insulation against the high voltage and currents of today's servo drives, and from Class H insulation that complies with UL requirements.

The SR Series is similar in design to Inmoco's more highly specified GS series of linear actuators, but with a reduced subset of features at a lower cost.

As such, the range offers the ideal solution in applications where competitiveness is a key concern, and where the options and/or dynamic load performance/life of a GS actuator are not really required.

Optimising the SR design in this way means that the units are competitive with low cost ball screw actuators, but, importantly, provide two to three times the life of the latter units, when compared size-for-size.

Despite their overall lower cost, the SR Series actuators still benefit from Exlar's patented and well proven inverted roller screw mechanism, as the means of converting rotary motion, from a brushless servo motor, into high- speed high-thrust linear motion.

The mechanism has a lead accuracy of 25um/300mm for high precision operation, and offers nominal backlash of 0.10mm.

It is designed into compact 84 or 99mm frame sizes, to produce packages that offer users a range of strokes from 40 to 305mm, force ratings up to 9619N and linear velocities to 635mm/s.

Selection of the suitable feedback medium (encoder with MS style connectors) offers the advantage of enabling the SR Series actuators to be powered by nearly every brand of brushless motor amplifier on the market.

This flexibility allows SR Series actuators to be incorporated into the highest performance single and multiaxis motion control systems in use today.

In applications varying from test rigs and semiconductor manufacturing, to aircraft assembly, the SR Series of actuators show incredible performance and durability.

The task of mounting the SR Series actuators is simplified by the tough, square, anodised aluminium housing, which is sealed to IP54.

The design lends itself both to front-flange or rear clevis mounting.

In addition to security in mounting, the integrity of the assembly, both in terms of environmental and "noise" terms, can be optimised with the option of moulded, shielded cables.