New DDC pump promises longer life

Hydraulic systems & components

Fourth Quarter 2007 Hydraulic systems & components

A new direct displacement control (DCC) pump that will reduce installation time, increase overall machine life, add extra flexibility to the vehicle design process, and help lower noise levels, has been introduced by Sauer-Danfoss. A key feature is the pump's built-in neutral return mechanism (NRM). All DDC pumps need such a mechanism, but on most competing products it is placed outside the pump - a complex, external unit containing linkages and springs.

Sauer-Danfoss’ new direct displacement control (DCC) pump

The NRM on the Sauer-Danfoss pump is placed inside. The pump therefore requires a minimised installation effort relative to a solution with external linkages and springs. The integral design also saves space, leaving room for other application components. Another important benefit is longer machine life. Because the return mechanism is located inside the pump - protected and always lubricated - end-users will experience more consistent machine operation and longer service intervals.

Ron Sheehan, business unit manager, Danfoss, explains, "Historically DDC pumps have featured external neutral return mechanisms which were subject to contaminants that include everything from dust and dirt to sticks and stones. In such designs, external wear points, friction, and machine vibration also add to maintenance needs and, over time, NRM performance may degrade. Placing the mechanism inside the product, we have eliminated this problem. Our testing shows that the pump's return performance continues to stay within extremely tight tolerances. The result is longer service intervals and longer machine life benefiting vehicle manufacturers and end-users alike."

Sauer-Danfoss' DDC pump also offers the very thing that vehicle designers appear to covet more than anything else: flexibility. The explanation lies in the pump housing. The manufacturer claims that the new pump is the industry's only DDC solution offering three displacements in one housing - 25 cc, 30 cc and 35 cc. For design engineers working on more than one model at the same time, three displacements in one housing size is a feature that adds a new level of flexibility. The pump installation process is the same for different vehicle models, thereby allowing engineers to spend more time on other design issues.

The pump is designed for closed-loop machine operations and ideal applications include wide area mowers, green mowers, sweepers, mini excavators, walk-behind skid steer loaders, and small tractors - machines that may all be used in areas where high noise levels can be an issue. Sauer-Danfoss engineers took this into account at a very early stage of the design process.

"Lower noise is an important issue for applications that operate in areas where people live and work," says Sheehan. "Reducing and improving the sound quality was therefore one of the project objectives during the development phase. We believe the result speaks for itself. Both the sound level and the sound quality have been improved. In fact, the DDC pump is up to 4 dB quieter than similar products available on the market and the nature of the sound or the sound quality is better, too."

For more information contact Ron Sheehan, Sauer-Danfoss, +27 (0)11 803 8390, [email protected], www.sauer-danfoss.com

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New DDC pump promises longer life

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