A new cartridge-style hydraulic motor has the potential to help designers of skid-steer loaders and agricultural vehicles pack more propulsion power into the tight quarters around the wheels of their machines. Known as the LC cartridge-mount motor, the new product is designed as a solution to the space-constraint dilemma facing designers of propulsion systems for such vehicles. Engineers at Sauer-Danfoss Inc. (www.sauer-danfoss.com), makers of the new motor, say that it offers a profile that's about two to three inches shorter than those of competing SAE-mounted motors, thus providing OEM designers with the critical space they need for increasingly larger turning assemblies, gearboxes, axles, hoses, and fittings.
"In these situations, the engineer is trying to shoehorn as much as possible into a very limited amount of space," says Randy Rodgers, hydrostatic product manager for Sauer-Danfoss, Inc. "Two to three inches of extra length can be a godsend for some of these steerable axles."
Sauer-Danfoss engineers say that the two-position hydraulic motor is suitable for medium-duty applications such as aerial work platforms, small agricultural sprayers, light- and medium-duty power construction equipment, turf care systems, and road building machinery, in addition to skid-steer loaders. The 20-hp motors offer 1,450 inch-lbs of peak torque. A 30-hp version of the cartridge motor, due out in December, will offer 2,220 inch-lbs of torque.
Sauer-Danfoss engineers say that the key to the space-saving design is a configuration that fits within the confines of the gearbox and mates to it through a standard bolting pattern.
"The whole idea of the design is to draw as much of that motor as possible into the gearbox," Rodgers says.
With the LC motor mounted in place on the gearbox, engineers must deal with about 4.2 inches of length, measured from the mounting flange to the back of the motor. In contrast, a comparably-rated SAE-style mount accounts for about 7.2 inches of length, which means that engineers who employ the cartridge-style motor gain an extra 2.3 inches of space near the wheel.
Space saving design
Equally important, Rodgers says that the LC enables engineers to save space because its configuration allows for attachment of all hydraulic hoses on a single motor face. That's important, engineers say, because most off-road hydraulic applications use four hoses–including two high-pressure lines, one case drain hose, and another line to shift the motor. Such hose jumbles can be difficult to package near hefty axles and steering assemblies. But by placing all the hoses on one side of the motor, Sauer-Danfoss engineers say that packaging is less difficult.
"Compactness of the motor is very important, but equally important is where you put the attachment points for all the hoses," Rodgers says. "If you place them all on one side, then the OEM engineer can wrap them and bundle them more easily."
To be sure, Rodgers says that competitors offer similar cartridge-style motors. He says that he expects those motors, as well as Sauer-Danfoss' new model, to gain traction in a growing number of off-road applications in the next few years.
He adds that the upcoming KC motor (due out in December) could be particularly well-suited for larger skid-steer loaders, on which OEMs typically need more powerful hydraulic propulsion systems.