The gearbox challenge

Paul Boughton

With increasing demand for mined minerals comes a requirement to increase output and improve efficiency and a large part of this challenge falls on the machinery and its ability to deliver reliable production from a robust, versatile and compact design.

The use of planetary gearboxes is widespread due to their compact design and ability to provide high output torque in applications such as bucket-wheel excavators with industry leading energy efficiency figures. 

Most manufacturers will offer in-line and right-angle designs but there needs to be a range of sizes to ensure that each application is fitted with the most suitable configuration without adding unnecessary weight or bulk.

The Brevini S Series offers a good example of the benefits this technology can bring, delivering 60 per cent more power (nominal output torque up to 5,000KNm) that traditional gearboxes of the same size.

Once the minerals have been mined they require transport and processing, both of which are continuous operations that require robust, high power output, versatile gearboxes to ensure the process continues uninterrupted. The more common choice is a helical or bevel-helical gearbox which can be constructed to suit each piece of equipment  and also fitted with a range of options to suit such a wide range of applications.

An example of such a solution would be the Posired 2 range from Brevini (, which is available in a modular format in 25 sizes with a nominal output torque up to 1,000kNm. As a very adaptable product, it can be used to replace existing, end of service equipment without making alterations to the existing structure. In most cases the new gearbox will provide additional capacity as well as new features without affecting the overall size and weight of the base equipment.

Parallel shaft lifting gearboxes have been developed by several manufacturers for large cranes and hoists, where the motor and cable drum are in parallel. These units should be capable of output torques up to 1,000KNm and available in a range of sizes with all the necessary accessories such as clutches, brakes and couplings to ensure that each specific application is accommodated.

Apart from the static mining and processing equipment, there is also the large amount of self-propelled machinery which requires equally robust and reliable drive systems to suit the demands placed on this machinery. In equipment which requires wheel drive units or track drive units, a compact design is crucial to maintain the plant efficiency, while ease of maintenance is important in the day-to-day running.

Track drives are required to fit inside the drive sprocket of the machine and as such must be capable of providing reliable and efficient service while being compact in design but also capable of including features such as brakes and disconnect devices to allow the vehicle to be towed. The working conditions of such drives can be very harsh so they must be engineered with suitable reductions for the applied load and with appropriately specified sealing to withstand mining conditions.

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