Putting the brake on linear motors

High-speed linear motors in CNC lathes reduce machining down time and maximise production efficiency, but high-performance brakes are crucial to their safe operation.

High-speed linear motors in CNC lathes reduce machining down time and maximise production efficiency.

The new Roba-Linearstop safety brake, which has been specially developed for use in linear motors, is also totally reliable where high speed demands are made day in and day out.

The brake is released hydraulically and operates in a fail-safe manner.

For the linear drive to operate safely - particularly in vertical or inclined axes, the reliability of the brake system employed is of crucial importance.

With the Roba-Linearstop Mayr Antriebstechnik has developed a brake that fulfils every demand made by the modern electric linear drive.

Thanks to its robust construction, this novel patented brake is superior to previously available designs in important respects.

Unlike other linear brake systems currently available, the Roba-Linearstop does not travel with the slide.

This simplifies the delivery of the supply lines.

As Gildemeister has just demonstrated with a new machine tool, the brake can be attached onto a fixed machine part.

A cylindrical rod, which is passed through the central bore of the brake, is connected to the slide of the linear drive.

When the slide is operational this brake rod moves axially inside the Roba-Linearstop.

This arrangement guarantees a very high degree of safety and reliability in operation.

In Gildermeister's CTX 420 linear machine tool, the Roba-Linearstop's main function is as a backlash-free holding brake.

However, it also brakes the slide against the effects of gravity - for example, following a power failure or emergency stop - and brings it to a standstill within 4mm as required.

A counterweight reduces the acceleration, and at the same time ensures that the gravitational effect is fully compensated.

Its high performance allows the Roba-Linearstop to achieve the holding force of 8000N specified by the machine tool manufacturer without difficulty.

A further crucial feature of the development was the requirement that the brake should operate without backlash during load transfer.

With a load of 2000N the lowering of the axis is less than 0.01mm and so in this respect too, the brake completely satisfies the machine tool manufacturer's requirements.

This movement occurs, not from play inside the linear brake but from unavoidable minimal elastic deformations within the system.

The new Roba-Linearstop has been developed by Mayr Antriebstechnik specially for this high speed linear drive.

It is a brake design which also has a key role to play in the general debate about additional safety features of vertical axes.

Loads which are transported vertically and suspended pose an enormous danger to operating staff and others who find themselves in the workplace for whatever reasons.

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