Drive is delivered through a hydrostatic transmission system with two variable displacement axial piston motors installed horizontally along the machine's lengthwise axis.
Bonfiglioli has launched a new drive unit designed for driving road roller wheels. These robust units are specially shaped and sized for installation on roller-compactors that generally feature rear axles with four drive wheels and steering front axles with idle wheels. Only two units are needed to drive all four wheels on the rear axle, each unit powering two wheels.
Drive is delivered through a hydrostatic transmission system with two variable displacement axial piston motors installed horizontally along the machine's lengthwise axis at 90 degrees to the wheel axis, in a position where they are well protected but still easily accessible.
In design terms, the drive unit comprises two hubs, on which the two driven wheels are mounted.
Each hub contains a double-stage planetary gearbox.
Inside a central connecting housing a bevel gear pair provides initial reduction and receives drive from a hydraulic motor through a mechanical drive shaft.
The central casing also provides the fixing points for securing the unit to the machine.
The load bearing hubs are designed to withstand the particularly high loads that road rollers apply to their wheels.
A multi-plate hydraulic brake is mounted at the input to the drive unit to provide dynamic braking to stop the machine (assisted by the braking effect of the hydrostatic transmission and diesel engine), and static braking for parking.
Hydraulic fluid passes through the braking system and is cooled by the machine's on-board cooling system.
Heat generated by braking, and especially that generated by speed control and braking on long downhill slopes, is thus removed and dissipated.
Tyre pressure can be controlled and adjusted as required due to a pipe that passes through the rotational axis of the wheel hubs.
This pipe is connected to the machine's compressed air system via a rotary joint and feeds two compressed air drop lines to the two tyres.
The unit is fully enclosed and all internal components, including the drive shaft, are fully protected.