Posted to News on 14th May 2008, 14:50
Two-stage helical-bevel gearboxes save weight and cost
Helical-bevel gearboxes provide a speed reducer function that can deliver power transmission efficiencies of over 95 per cent. This can be up to twice that of the worm-style gears that are commonly used, providing major savings in energy consumption. Nord Drivesystems is now introducing a range of two-stage helical-bevel gearboxes in lightweight diecast aluminium housings, which are claimed to provide considerable cost savings compared with established cast iron products. In addition, the highly efficient gearboxes enable automation builders to reduce costs by specifying smaller sizes of electric motor.
Nord's SK 92 series of helical-bevel gearboxes provide a right-angled drive capability that can be configured to provide speed reduction ratios from 3:1 to 72:1. Typical applications include baggage handling equipment, conveyors as well as packaging and processing machinery. Five reducer sizes are available, spanning a power range from 0.12-9.2kW.
The new gearboxes are claimed to reduce system building costs significantly for automation vendors. Two-stage helical-bevel gearboxes are said to support a wider choice of ratios than is possible with worm gears. Each SK 92 case size can be configured with a choice of up to 21 ratios, compared with perhaps nine for single worm gearboxes. In many applications, this can eliminate additional components such as a belt or chain system. Most helical-bevel reducers on the market are also typically based on three stages, with a helical input followed by bevel and helical reductions. However, SK 92 gearboxes have just two stages, thereby eliminating gear, bearing, shaft and other minor component parts and minimising the implementation costs of the technology while maintaining higher power transmission performance.
Longer operating life is another important attribute of helical bevel gears. Compared with worm gears, helical bevel units are virtually wear-free and run cooler.
Modular design principles enable the SK 92 series of reducers to be customised using a broad range of accessories to provide optimised power transmission for virtually any application. As standard, units offer foot mounting on two sides, B14 face mounts on two sides and either a hollow or solid output shaft. Nord's range of accessories and its in-house assembly facilities ensure that a wide variety of gear designs can be configured using just a few modular parts, giving great design flexibility as well as interchangeability with other manufacturers' products for repair and refurbishment applications. Among the accessories available are bolt-on type flanges and torque arms. Nord can also supply the units in ATEX-compatible form and as complete geared motors rated up to EFF 1, complete with accessories including encoders, brakes and forced ventilation.
