The ‘S’ series shaft motors from Micromech are a very simple design, have very high accuracy and non-contact. What are shaft motors, they are direct drive linear servomotors that consist of a shaft with laminated magnets and cylindrically wound coils controlled by the flow of current.

Shaft motors are a simple construction that use magnetic circuits consisting only of permanent magnets and coils and which result in a wide range of characteristics. The characteristics include precision positioning, high and low constant speed performance thus making the range of applications extremely diverse. Furthermore the ‘S’ series has combined linear encoders, encoder guides and mechanical systems to meet customers' requirements making them ideal actuators for their individual applications.

When comparing these shaft motors to the more commonly known linear motors there is another difference besides the obvious that one is cylindrical and the other is flat. The standard versions of most motors including linear motors is that the circuits are made of magnetic iron while shaft motors are not. For this reason there is no adsorption force between the shaft and forcer (coil) thereby totally eliminating cogging.

A further outstanding feature of shaft motors is they are capable of amazingly high thrust for example 2340 N with a single forcer and 9360 N using four forcers (parallel plus tandem drive). The ‘S’ series is very quiet due to the absence of friction; the only mechanical contact section is the linear guide. This can be improved still further using an air slider where full non-contact operation is possible.

The coreless construction reduces overall weight and the simplified unit construction allows a stroke of up to 3.8m with high resolution of 0.14m, which is ideal for precision positioning. There is a high-speed drive delivering 6.5m/s and low-speed drive down to8um/s and virtually no speed fluctuations (+/- 0.006% at 100m/s).

The shaft motors are a rugged and durable construction, capable of operating in a vacuum but compact and lightweight compared with other linear motors. For volume applications they can be designed as optimum actuator modules that maximise their features to meet customers' particular requirements.

Shaft Motor Drive System
The single-shaft drive uses a control system matched to the combination of a shaft and a forcer so as to enable control system to suit the specific requirements, even for complex movement.

Single Drive
This is the basic drive system. The x and y shafts can be used to create and xy stage

Multi Drive
Multiple forcer can be controlled by a single shaft, thereby supporting complex movement.

Parallel Drive
Effective for driving large or heavy objects

Tandem Drive
Allows the thrust to be increased through combination of the forcer

Shaft motor characteristics and typical applications
A wide range of applications utilising the characteristics of shaft motors is listed below. These can be used in a diverse range of practical application, such as precision positioning, operation under adverse environmental conditions, and for the conveying of heavy loads.

High Thrust
For conveying heavy loads such as clinical equipment or for use on factory production lines

Friction free and quiet
For use in quiet surroundings such as test laboratories or medical facilities

3-meter stroke
For the high precision of conveying of large devices such as LCDs over long distances

High resolution
For precise positioning for semiconductor systems

High-speed drive
For high-throughput conveying for the printing of line head drives

Low-speed drive
For equipment that is difficult to handle using ballscrews

No speed fluctuations
For constant-speed drug dispensing that is difficult using ball screws

Environmental compatibility
Operates in production locations where water or oil is used, or in a vacuum

For more information contact Alan Spinks on 01376 333333 or email alan@micromech.co.uk