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Servomotor, roller screw and encoder combined

An Inmoco product story

Edited by the Engineeringtalk editorial team Oct 30, 2000

The unique new GS40 linear actuator from Inmoco combines a brushless servomotor, an inverted roller screw and an encoder/resolver feedback source into a single compact assembly.

The unique new GS40 linear actuator from Inmoco combines a brushless servomotor, an inverted roller screw and an encoder/resolver feedback source into a single compact assembly.

This arrangement eliminates the cost and complexity of a systems engineering approach as all elements for producing linear motion have been properly matched and designed into the actuator and tested for their efficiency.

The GS40 is the latest introduction to Inmoco's unique GS series of inverted roller screw actuators.

A 99mm frame size unit, the GS40 offers users a range of strokes from 152mm to 457mm, continuous force ratings up to 5337N, and linear velocities to 635mm/sec.

These performance figures place the GS40 in the medium range of the GS series overall.

At the top end of the range the GS60 (178mm frame unit) is capable of providing continuous thrust ratings up to a maximum of 35,600N and speeds to over 1m/s.

The brushless servo design of the GS series linear actuators allows them to be used in state-of-the art closed loop servo systems, where electronic control of positioning and velocity is required.

In these systems position feedback can be provided in a number of different forms to match customer specifications, including resolvers, encoders or internally mounted linear position feedback sensors.

The GS series actuators employs an inverted roller screw mechanism to convert the rotary motion of the brushless motor into high speed, high thrust linear motion.

This mechanism has a lead accuracy of 25um/300mm for high precision operation and can also be supplied with zero backlash.

The large contact area of the roller screw - this due to rollers rather than balls - allows high force characteristics while guaranteeing long life - 15 times the life of comparably sized ball screws is common - even in the most demanding repetitive applications.

In addition, the planetary design of the roller screw allows it to be accelerated and rotated faster (up to 5,000 rpm) than comparably sized ball screws.

GS series actuators offer additional benefits in the form of contamination protection.

In conventional rotary to linear devices the critical mechanisms are exposed to the environment and therefore require frequent inspection, cleaning and lubrication.

In contrast, all converting components in the GS series actuator are mounted within the sealed motor housing which is IP65 rated, (IP67 upon request).

The smooth extending rod allows the use of a bushing and seal arrangement, which prevents abrasive particles and other forms of contamination from entering the actuator's critical mechanisms.

This assures trouble-free operation even in the most severe environments.

Lubrication requirements for the GS series actuators are minimal.

Designed to be lubricated with either grease or recirculated oil, they can be run for up to 10,000 hours between re-greasings.

Recirculated oil lubrication eliminates the need for lubrication maintenance altogether: an oil lubricated GS actuator will operate indefinitely with no servicing requirements.

The GS actuators are available in a wide variety of stroke lengths, sizes, speeds and mounting configurations.

Inmoco can also supply custom actuators to fit special applications.

The capabilities of the GS range are extended by a wide range of optional features including; internal end switches, electric brakes, linear positioning sensors, backlash free followers and multiple mounting and rod end configurations.

GS actuators are suitable for use in many demanding applications including, automatic tool changers, dispensing, wire guiding, chip and wafer handling, robot manipulation, testing, web guidance, indexing material cutting, tension control and many, many, more.