How Power Transmission Technology Has Moved On

At one time, engineering power transmission components brought back memories of high grade steel components being manufactured in machine shops reeking of cutting fluid and lubricating oil. For example, gear grinding to give the gear tooth profile was a time consuming business requiring high workshop skills.

These days a great deal has changed, not only do we have full CNC machining, but now a whole range of new high-performance plastic materials being used for the small and medium sized power transmission sector. The redolent reek may still be there in some specialist machine shops, but the technology has been shaped both by innovation of new technology and the application of ever-increasing cost efficiency measures that the modern world demands for survival.

These are the drivers that have changed the manufacturing landscape. There is now a large range of off-the-shelf components and assemblies that have been engineered around the world to provide all conceivable combinations of air drive or electric motors, spur gear heads, axial gear heads, couplings, shafts and other power transmission components.

Innovation and out-sourcing for specialist products have driven a revolution in highly specialised modular manufacturing much to the benefit of first-line manufacturers of end-user equipment.

Take for example, piston air motors. These little motors with torques up to 80 Nm, are driven by compressed air. With their acetal plastic body construction, they are fast catching on for such diverse applications as switching servo motors for substations as well and as air source control drives for medical machinery and machinery in hazardous spark-free environments.

Typically, they feature a 3 piston radial arrangement and they are available both as standalone with a drive spindle, or with integral planetary, spur or wormwheel gear heads. With high-ratio reduction gearing up to some 300:1, these little motors are highly controllable and they are successfully employed giving precise positioning control both linearly with worm gearing, or rotationally.

Proximity pulse counters attached to each cylinder head can provide the digital output necessary for electronic control. Low weight and a crisp response at start up courtesy of maximum torque being developed; give these arrangements a real niche for precise control.

I was struck by the enormous range of gears available on the market and this range is growing all the time. A typical supplier's portfolio contains, for example, spur gears in steel, stainless steel, brass, Acetal and Delrin. The latter two are high performance thermoplastics with a high Young' Modulus and a high operating temperature range. Acetal with its superior stability has the gear teeth machined with helical or straight-cut profiles.

Also to be found in these supplier portfolios, are a vast range of high performance power transmission components. Again, high-performance thermoplastic and elastomer components are strongly featured. Take for example, precision couplings that can take a high degree of angular and axial misalignment and still efficiently deliver power across the coupling without undue vibration and noise.

Also to be found are universal joints, shafts, worm shafts, clutches that first make prototyping easy during the development phase of a machine as well as for the volume production phase.