Paving machines

Photo | Dynapac GmbH
Marginal Column

July 2011

 

A uniform concept for hydraulic and electrical components. A modern production strategy nudges the new series of Dynapac paving machines into the fast lane.

 
 

Each and every year, ten thousands of kilometers of streets and roads are built around the world. But there’s one machine that has to finish its work before vehicles can occupy those arteries. That’s the paving machine, which lays asphalt, like a black blanket, on the prepared base course. It can process up to 1,100 tons of material each hour. That’s a huge assignment, for both man and machine. That is why Dynapac, as it engineered this new generation of pavers, attached equal importance to performance and user friendliness. Dynapac GmbH, a global player in construction machinery, is setting benchmarks with an intelligent link between the electronics and the hydraulics.

“We have adopted a modular construction principle, one we will be using for other models, too,” reveals General Manager Thorsten Bode. The first six versions are now ready for market – two models with electro-mechanical control and four with PLC. When selecting the components installed here, Dynapac and its suppliers embarked on new paths.

New concept for the hydraulics

Photo | Dynapac GmbH

Wherever possible, the hydraulic components are placed at the side of the machine to facilitate maintenance.
Photo: Dynapac GmbH

 

“Our partners to deliver the three central systems – internal combustion engine, hydraulic, and tamping beam – were selected early on. Close cooperation quickly ensued,” explained Carsten Bernhardt, Manager for Design und Development. The decision to select Rexroth as a partner was based in no little part on almost twenty years of successful collaboration in the past. Thomas Müller of Sector Management for Road Building Machinery was appointed as the Rexroth project director. He was responsible for coordinating all the trades, products and manufacturing sites. “This made it possible for us to contribute expertise in many industries, accumulated over decades,” he explains. “In this way I could, as needed, get experts from our company involved in the project.” They always found the best solution for every question – quickly and without additional communications effort for the customer. The ultimate result was a hydraulic concept that is convincing not only because of its high performance, but also because of its ease of maintenance. Wherever possible, all the hydraulic components are grouped together in the machine to achieve good accessibility.

Better control

Photo | Dynapac GmbH

Rexroth’s central electronic system permits measures to considerably reduce energy consumption and noise emissions.
Photo: Dynapac GmbH

 

The electronics need fear no comparison. Dynapac devised a modular control concept for the new road finishers. In the smaller units it commands the electro-hydraulic propulsion drive, while in the four larger versions the controls mimic the entire machine. A large share of the development work, consuming several man-years of work, was devoted to adapting the control functions to meet specific needs. According to Eberhard Lürding, project manager responsible for the work, this effort paid off for one particular reason: “We avoided using separate electronic units that would be operated with different interfaces and tools in each case.” That is why Rexroth developed a central electronic system into which third-party systems – such as regulators for tamping beam heating and functions – are integrated. Only one more process computer is needed – for leveling – and it also exchanges information with that central electronic unit made by Rexroth.

Persuasive new features

The central electronic concept let the developers realize a number of functions which simplify everyday work for the road building crew. The driver can select the “Variospeed” mode, in which the speed of the diesel engine is automatically matched to current power demand. The same operating principle is used for the hydraulically driven fan, which always regulates itself to the appropriate duty point. This not only makes the paving machine more economical; it is also easier on the ears, both for the road crew and those living near the construction site. The “Safe Impact” function also facilitates paving material refills during operation: “When a truck that fills the supply hopper bumps the paver during docking, that impact will cause unevenness in the road surface,” explains Carsten Bernhard. “We offer an optional, hydraulically damped advancing roller that absorbs this shock and makes for a flat and level wearing course.” In the operator’s cab, too, user-friendless enjoys high priority. In its PLC-controlled machines Dynapac implemented an intuitive operating menu for the driver, based on the BODAS DI3 color display. Already considered in the control concept are the wheeled pavers scheduled to be introduced by Dynapac in coming months.

Photo | Dynapac GmbH

Before its market launch, the new Dynapac road finisher proved its mettle in numerous practical tests.
Photo: Dynapac GmbH

 

Fewer parts, more service

The common parts policy aimed for by Dynapac has also been complied with in the new roadway finishers. “We were able to reduce the number of discrete components by thirty percent,” is how Purchasing and Logistics Manager Thomas Matten sums up the situation. “That simplifies logistics and assembly and, at the same time, enhances parts availability for service work all around the world.” Management is thoroughly satisfied with this new type of cooperation – as are the customers. All the roadway construction companies that tested machines from the pre-production series were unanimously enthusiastic. Surprisingly, there was praise from an entirely unexpected quarter, as Product Manager Volker Behrens reports: “We even received compliments from the competition.”