Team Problem Solving

When it comes to pumps and motors, equipment designers have plenty to choose from. The ability to direct energy throughout a machine in neatly packaged systems has given designers the freedom to create machines that best fit the intended function.

Helping make that decision are the product managers at the various component suppliers. In this issue, we look at a few examples of where expert help provided solutions for equipment manufacturers.

In the closed center variant of DanTruck's new lift truck, the Denmark-based manufacturer uses a Bosch Rexroth axial piston variable displacement pump with a particularly low noise level. © Rexroth

From an Inquiry to a System Partnership

edited by OEM Off-Highway

DanTruck A/S of Uldum, Denmark, a builder of forklift trucks with a capacity of up to 9 tons, recently revised one series of its trucks with the latest in mobile hydraulics and electronics.

We had actually inquired about prices from various manufacturers about hydraulic components, in order to reduce the manufacturing costs of our 9000 Series," says Morten Gregersen, development manager, DanTruck. The company supplies three series of forklift trucks for handling loads between 4 and 9 tons.
Bosch Rexroth application engineers suggested a new approach, in which DanTruck could not only reduce costs, but also gain more flexibility for customized solutions.

Rexroth and DanTruck worked on a profile where requirements, wishes and a few new ideas flowed together. The result: a system solution for the working hydraulics, the steering equipment and the brakes, as well as the fan drive for the diesel engine. The system consists of the control block M4-12/15 with load sensing, with the pressure and volume flow matching the immediate requirements of one or more users.

In the forklift model with an open-center hydraulic system, DanTruck integrates the Rexroth Silence external gear pump, known for its low volumetric flow pulsation, one of the major sources of noise from this type of pump. An axial piston variable displacement pump supplies the oil flow in the closed-center variant of the truck. In both, the goal of DanTruck to build the quietest forklift trucks of their class are supported by the pumps.

The variable displacement version also reduces fuel consumption. As well as the machine's actual working hydraulics, the pumps supply external equipment through programmed functions. "We are moving the changes from the hardware into the software," says Gregersen. "In this way we can react to the customers' wishes after delivery."

© Poclain

Small Steering Motor

by Chad Elmore

For years, Poclain Hydraulics has offered a range of hydraulic motors for steering wheels. Models from its MG Series have been popular on the rear axles of combines as well as other applications in large equipment. When a German manufacturer asked for a smaller wheel motor that could be used to steer its compact equipment, Poclain engineers got to work.

"The main challenge with this development was to make a compact product," says Jean-Marie Perret, marketing manager - North America, Sturtevant, WI. "But it also had to be robust to comply with extremely demanding specifications."

Recently introduced, the lightweight MG02 motor can shorten the turning radius of machines compared standard steering axles or articulation, thanks to its swivel angle. The MG02 also allows for design flexibility and machine stability.

"In an articulated machine, the steering angle is defined by the machine's pivot joint," says Perret. "Stability also limits the steering angle. When steering, the center of gravity moves toward the machine's outside and creates a risk of instability.

"MG02 motors help a machine maintain its center of gravity, even during a tight turn."

H1 motor © Sauer-Danfoss

A Common Goal

by Chad Elmore