This new drive unit is specifically designed for driving road roller wheels. It is specially shaped and sized for installation on roller-compactors which 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° to the wheel axis, in a position where they are well protected but still easily accessible. In design terms, the drive unit comprises 2 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. A pipe passes through the rotational axis of the wheel hubs. This is connected to the machine's compressed air system via a rotary joint and feeds two compressed air drop lines to the two tyres. Tyre pressure can thus be controlled and adjusted as required. The unit is fully enclosed and all internal components, including the drive shaft, are fully protected.

This type of drive unit is specially designed to drive wheels on graders in the 16 tonne class. Drive is delivered by a cartridge type hydraulic motor. This design has been adopted for its minimal protrusion, permitting the entire unit to be housed inside the width of the tyre. This ensures excellent protection for the drive unit whatever the machine configuration, even in the most severe operating conditions. In design terms the unit comprises a hub that houses a planetary gearbox with two reduction stages and a hydraulically operated multi-plate clutch. The clutch can be engaged when the machine is stationary or moving. When the clutch is engaged, drive is transmitted to the wheel; when it is disengaged the wheel is idle. A special drive pressure control system, connected to the hydrostatic transmission control system and to the main rear wheel drive, ensures smooth and safe engagement when the speed of the hydraulic motor matches that of the driven wheel. All aspects of control are managed by an electronic control unit.

The clutch is mounted on the final reduction stage of the planetary gearbox and is characterised by low rotational speed and therefore, reduced power loss and reduced heat generation in neutral when the machine is travelling from one location to another at high speed.

Track drive gearboxes for crawler machines, series 700C and 700CK

New improved medium sizes The medium sizes of these acclaimed gearboxes and gearmotors for tracked crawlers now feature a new, improved design offering output torques in the range of 15000 Nm to 60000 Nm. The following sizes feature the new improved design: - 707 - 709 - 710

The purpose of the design changes was to:

• improve performance
• reduce or retain the same size and improve interchangeability, to make the units more compact and easier to install
• enhance competitiveness
• extend the 700CK series range with Kayaba motors and the following new sizes: 707C2K, 707C3K

The main design changes compared to the previous models are:

• Fewer components.
• Expansion of the number of planetary gears in the final reduction stage from 4 to 5.
• New, more robust final stage tooth profiles, and more teeth for a wider range of possible ratios.