Mobile equipment on display offered attendees a close-up look at innovative hydraulic systems.

Mobile equipment on display offered attendees a close-up look at innovative hydraulic systems.


More than 1,200 mobile-equipment engineers representing leading OEMs from 60 nations recently convened at the Bosch Rexroth Mobile 2006 conference in Ulm, Germany. The event, held every three years, is reportedly the world's largest mobile-hydraulics conference.

A common objective for OEMs and suppliers alike is to produce safe, clean, fuel-efficient machines, says Manfred Grundke, chairman of the executive board of Bosch Rexroth AG, Lohr am Main, Germany. Mobile 2006 provided a much-needed forum to discuss how manufacturers can best meet these goals, debate future requirements, and showcase new and innovative electronic and hydraulic technologies, he says.

Four key factors are driving the mobile-equipment business today: environment, energy, function, and cost, according to Helmut Wagener, chairman of the company's hydraulics business unit. Twenty-four technical lectures examined these issues and how they relate to specific vehicles such as excavators, wheel loaders, and cranes.

On the environmental front, for instance, tighter exhaust-emission regulations are an ongoing concern for equipment manufacturers and users. Electronic controls linking engine-management software with hydraulically driven auxiliary functions are now key to meeting current and future clean-air requirements, says Wagener.

Machine noise is coming under regulatory scrutiny as well, he says. One way fluid-power companies are addressing this problem is by structurally optimizing axial-piston pumps and reducing pressure pulsations using techniques such as pre-compression of the incoming fluid. Rexroth is also working to minimize environmental damage from hydraulic leaks. For instance, its redesigned A15VO piston pump has only one high-pressure seal versus 13 in the previous version.

With fuel costs recently at record highs, "energy savings is now a key, decisive sales argument for machine manufacturers," says Wagener. Standing-room-only crowds explored energy-regeneration techniques, such as methods to recover and reuse vehicle braking energy that's normally dissipated as heat. For instance, a Rexroth system installed on refuse trucks reportedly saves nearly $7,000 per year in fuel costs.

Other fuel-saving techniques include:

  • Hydromechanical-variable transmissions that efficiently link hydrostatics and mechanical gears and can shift on-the-fly.
  • Electrohydraulic-flow matching using variable-displacement pumps to deliver the exact flow a vehicle demands, no more and no less.
  • Split-flow pumps that replace tandem pumps and reduce valve-throttling losses.

There is also increasing demand to automate repetitive functions and improve operating efficiency, enhance productivity, and reduce operator fatigue. Hydraulics companies now offer reliable electronic and software packages, such as modular mast and arm controls that handle monotonous tasks.

At the component level, hydraulics manufacturers are building higher-pressure systems that are smaller and lighter; using CFD simulations to improve pump efficiency; and applying low-friction coatings to eliminate slip-stick problems in valves for better control.

Rexroth officials report mobile-equipment users are more concerned than ever with total cost of ownership, not just a vehicle's sticker price. That's putting pressure on hydraulics suppliers to drive down component costs, improve reliability, and make them maintenance friendly. Condition monitoring and diagnostics are now critical. Systems that combine control electronics with appropriate software and sensors can measure, for instance, pump displacement, pressure, and speed, and deliver information that pinpoints potential problems and heads off unexpected failures.

The conference also showcased 84 innovative machines ranging from excavators, wheel loaders, and dozers to drilling equipment, forestry machines, and snow groomers. These afforded attendees a hands-on look at various new hydraulic and control strategies.