Evolution of the trapezoidal thread: New igus standard achieves 82 percent efficiency

Even the tried and tested has potential for improvement. One example is the classic trapezoidal thread, which igus has further developed. Thanks to a special geometric interaction of metal spindle and lubrication- and maintenance-free threaded nut, dryspin technology promises a long service life, improved efficiency, low wear and less movement noise. Now dryspin thread technology is available in eight new sizes.

Trapezoidal threads have been classics in mechanical engineering for decades. The machine elements convert a rotary into a translatory movement – for example in window or door drives, for format adjustments in production plants or in laboratory technology. But almost every classic has potential for improvement. “We have ventured to set a market standard and say: there is room for improvement,” emphasises Thorben Hendricks, head of the dryspin screw drive business unit at igus. The motion plastics specialist relies on an optimised interaction of the geometries of metal spindle and plastic threaded nut.

30 percent longer service life and 82 percent efficiency

Compared to classic trapezoidal threads, the thread flanks of the igus nut are enlarged, as is the width of the thread of the spindle. A small intervention with consequences: Because due to the enlargement of the thread flanks, more high-performance plastic is used in the power transmission. More material that is tribologically optimised, i.e. in terms of friction and wear. “Through the asymmetry, we have managed to extend the service life by around 30 percent compared to symmetrical trapezoidal threads,” says Hendricks. The optimisation of the flank angle also increases the usable portion of the supplied energy. We have flattened the flank angle of the threaded nut and spindle. As a result, we achieve an above-average efficiency of up to 82 per cent at high thread pitches.”

Threads work with low vibration and almost no noise

The new dryspin thread technology is not only durable and efficient, but also quieter than many conventional trapezoidal threads. This is because the tooth flanks are not angular, but rounded. The contact surface between the threaded nut and the spindle is thus reduced. And that leads to fewer vibrations that can make themselves felt as rattling or squeaking. Hendricks: “Thanks to the rounded tooth flanks, the threads move vibration-free and almost noiselessly. The tighter manufacturing tolerance of the threaded spindles compared to DIN 103 7e also ensures more precise running behaviour and enables significantly higher speeds in the application.”

Portfolio of dryspin thread technology expanded by eight sizes

igus began establishing its own thread technology on the market in 2013, initially as an alternative to steep threads. Now eight new sizes follow – matched spindles and threaded nuts, including dimensions with low pitches that enable quick one-to-one replacement of installed trapezoidal threads. The new threads are available with pitches of 6.35×6.35 RH, 8×40 RH, 10×3 LH, 12×25 LH, 14×4 RH, 16×5 RH, 18×4 RH and 20×10 RH. The threaded spindles are made of stainless steel or aluminium; the threaded nuts are optionally made of seven high-performance plastics and several geometries – from a cylindrical design with collar or spanner flats to the variant with spring pretension.

For more information, please visit: https://presse.igus.de/