Dana Rexroth Transmission Systems announced in late November that it began pre-production testing of its R3 hydromechanical variable transmission (HVT) at several global OEMs.

Featuring a modular design, the HVT R3 can be adapted for a variety of configurations, including wheel loaders, motor graders, industrial lift trucks, reach stackers, forestry skidders and other off-highway equipment. The HVT R3 is designed for applications with net input power from 200 to 270 kW (268 to 362 hp), an increase of 65 to 75 kW (88 to 102 hp) over the HVT R2 (see http://articles.sae.org/12177/), which was introduced in 2013 and has been in production since 2016.

“As off-highway vehicles have evolved into increasingly complex and highly technological systems, expectations have also risen from both OEMs and operators demanding a smoother, quieter ride. The industry today requires a blend of fuel economy, performance and driveability,” said Roland Friedl, head of sales and product management for Dana Rexroth Transmission Systems, in a recent release from the company.

A product of a joint venture between Dana Inc. and Bosch Rexroth (see "Dana, Bosch Rexroth to jointly develop off-highway transmissions" http://articles.sae.org/8096/ for more), the HVTs reduce fuel consumption by decreasing engine speeds throughout the duty cycle and also at idle, when speeds can drop to as low as 600 rpm. Application analysis demonstrates the possibility of further savings without compromising performance through engine downsizing, the company claims.

Dana Rexroth HVTs enable sensitive, precise vehicle positioning with a stepless drive that offers improved acceleration while maintaining tractive effort. According to the company, they optimize the operating point of the diesel engine by decoupling engine speed from drive speed, and maintenance costs are reduced by using hydrostatic braking and wear-free directional reversing without clutches.

The HVT R3 helps reduce complexity for equipment manufacturers, since the entire system of gears, clutches and hydrostatic units is managed by an advanced electronic control unit and optimized for efficiency by a single supplier.