Linear motor axis with air bearing ELGL
In comparison to all other bearing forms, air bearings have one important USP: they work contactlessly. This means that in normal operation, there is no wear or abrasion on these bearings, and that they are practically maintenance-free.
Mode of operation
On an air bearing, an air cushion is built up between the carriage and the base. In order to allow the carriage to hover over the base, a force is required which counteracts the compressed air. This takes place using permanent magnets integrated into the carriage. When the air bearing is deactivated, the carriage is pressed by the permanent magnets onto the base. This means that the carriage is held in this position and cannot be moved. Thus the function of a holding brake has already been achieved within the functional principle of the bearing. If compressed air is then blown between the carriage and the base, the carriage starts to hover. The build-up of force, the compressed air and the counterforce generated by the magnets adjusts to a constant air gap within a range of 7 to 15 µm.
This small air gap requires a very flat base.
Through this flatness, high requirements on precision and linearity can be achieved.
Functional principle of a magnetically preloaded air bearing
This bearing principle can easily be combined with a linear motor, so that the result is a product which is ideally suited to applications with high precision and linearity requirements. The main applications are testing machines,
measuring machines and all applications for which the advantages of linear motors with air bearings are important:
• No oil or grease is used in any part of the axis. This means that lubricants cannot leak out and influence the process.
• The holding brake is already integrated into the axis due to the functional principle of the air bearing. Holding brakes on all other linear motor axes are very large and require additional space. This makes safety-orientated applications requiring a holding brake easy to realise.
• The bearing is wear-free, so that no particles can be generated and operation in clean conditions is possible.
• Several carriages can be operated on the same axis at the same time or independently of one another. There are various applications which provide a solution for several carriages on one axis. This saves time and costs.
ELGL-LAS, size 30 ELGL-LAS, size 64
These advantages have led Festo to develop the linear motor axis ELGL-LAS with air bearing and hybrid motor and launch them on the market. This linear motor axis has all the advantages listed above such as precision, linearity, wear-resistance and holding brake as well as a diverse range of accessories. Mounting brackets, sensor brackets, sensors, energy chain brackets, cables and motor controllers are all available from one source.
This makes the individual components easily combinable into a system solution which can be quickly integrated into an application. In addition, the freely available configuration software FCT (Festo Configuration Tool) allows quick and simple commissioning through an intuitively comprehensible user interface.
|Continuous force [N]||44||110||160||217||282||330|
|Peak force [N]||44||119||164||240||30||450|
|Maximum length [mm]||1000||2000||2000||2000||2000||2000|
|Repetition accuracy [mm]||±0.01||±0.01||±0.01||±0.01||±0.01||±0.01|
Advantages of the linear motor axis with air bearing ELGL-LAS
• The magnetically encoded measuring scale is well protected against ambient influences in a slot on the underside of the axis.
• The linear displacement encoder has digitally encoded signals which are constantly monitored so that the linear motor axis cannot run away when the displacement encoder has a failure.
• The flat, rotatable plug connector for connecting the linear motor axis to the motor controller saves space and can be adapted to the different installation and connection conditions of the application.
• In order to simplify installation on uneven mounting surfaces, adjustable mounting feet are available which can substantially reduce the installation effort.
• Shock absorbers or sensors can be integrated into the end stops for increased safety requirements.
• The sensor brackets have been designed so that the proximity sensors can be perfectly adapted to the application and can be adjusted as required in the area of the end stop.
• The linear motor axis is available in 3 different high-performance sizes in standard lengths up to 2000 mm, special lengths are possible up to 6000 mm.
• The standard lengths are finished according to the customer order and can be delivered within 10 working days.
• With the motor controller CMMP-AS, the linear motor axes are ideally integrated into the Festo controller concept.