Traditionally, vehicle drive systems have been based around axles — and in many cases they remain a solid solution. However, with vehicle manufacturers constantly looking to reduce size, weight, while still improving performance, fuel efficiency and profits, a different approach is required. Designers have been turning their attention to wheel and track drives which incorporate a planetary gear design
Compared to standard axle drives, wheel and track drives provide neater and more compact solution which provide improved ground clearance for rough terrain and off-highway vehicles. At the centre of this solution is the planetary gear design which comprises several smaller planetary gears rotating around the central input pinion gear which enables the gearbox to deliver high-reduction rations with a much smaller footprint to traditional helical or bevel helical gearboxes.
Brevini Power Transmission has been one of the pioneers of this technology and now boasts a wide range of industrial gearboxes and compact wheel and track drive systems. The Brevini planetary design claims a number of advantages which makes it an ideal solution for many mobile applications.
Thanks to the use of planetary gears it is possible to incorporate multiple reduction stages into a very compact space; the three planetary gears also share the radial load thus reducing wear and improving reliability. The design also has an increased torque capability due to the input torque being shared between multiple sets of teeth on the primary drive pinion. In addition, the planetary arrangement is highly efficient, up to 98 percent per stage.
Brevini wheel drives are used across a wide range of vehicles including agricultural machines, mobile access platforms, forklifts and heavy-duty wheeled vehicles up to 400 tonnes. This design combines the high-speed hydraulic motor with the planetary gear unit to produce a more economical package when compared to using a large low-speed motor on its own.
Reliable drive in harsh conditions
Track drive units are also used across many industries including mining and construction in tracked vehicles weighing up to 130 tonnes. The compact track drive unit is designed to mount inside the track sprocket and to provide a reliable drive solution even in the most severe of operating conditions.
Both of these drive configurations offer a wide range of reduction ratios, enabling the designers of mobile plant to match the drive unit with the most suitable hydraulic transmission. Further flexibility is is provided by the ability of the drives to accommodate the mounting of all types of orbital, geared and axial piston type hydraulic motors made by Brevini Fluid Power. In addition, Brevini has included the option of a mechanical disconnect device. This is manually operated from the hub end-plate and enables a vehicle to be towed in the event of an emergency.
Complementing this device is the additional option of an integral multi-disc negative parking brake, which is spring applied and hydraulically released. This functions as an emergency fail-to-safe brake should the hydraulic pressure fail and so is an important safeguard for mobile access equipment, which is sometimes manoeuvred with the platform fully raised.
With its wide product range, Brevini Power Transmission is able to provide a drive solution for vehicles up to 50 tonnes per wheel and up to a 3m wheel diameter. With the additional support of experienced design engineers, Brevini says it can ensure that the correct drive package is assembled for every application.