Diesel Progress North American Edition,
Sept, 2004 by Dawn M. Geske
Kubota Tractor Corp. has expanded its compact equipment line to include its first zero tail swing excavator, the U35. The new excavator joins the third generation of enhancements made to the company’s KX series of conventional swing excavators, along with upgrades throughout its Super Series wheel loader range.
Establishing the U series was part of a development by Kubota to complement its conventional swing excavators with a zero tail swing (ZTS) option, said Keith Rohrbacker, construction equipment product manager for the Calif.-based company. “Kubota wanted to satisfy the markets’ requirements for zero tail swing where needed. Part of that had to be in response to where other companies were bringing zero tail swing in. Part of it was tightening the tail swing on the KX series.”
Used mainly in sewer and water, building and residential, rental, landscape and communication and electrical applications, the U35 excavator has an operating weight of 3.5 tons while the KX series machines feature operating weights from 1.0 to 5.2 tons. The KX series is comprised of five redesigned models, the K008-3, KX41-3V, KX91-3, KX121-3 and KX161-3. A sixth machine, the KX61-2, remains to be upgraded.
Powering the KX line are Kubota’s three- and four-cylinder, liquid-cooled, OHV D and V series diesels. The Tier 2 engines are rated 10.2, 17, 28, 42.2 and 42 hp at 2050, 2300 and 2600 rpm, respectively. The U35 excavator is equipped with the three-cylinder D1503 diesel rated 28 hp at 2300 rpm. “Like everyone else, we had to go to a Tier 2 engine,” said Rohrbacker. “Our compact equipment just happens to be right where Kubota’s hp range fits in. We have a whole stable of Kubota engines to choose from, so we have complete control from the design to the engine application to the manufacturing.”
The engine uses a belt-driven F-shaped fan and proprietary oil cooler and radiator for cooling. The fan design aids in reducing the sound emissions, as do baffles placed inside the muffler and on the air intake. Additional noise reduction, Kubota said, is achieved throughout the engine through redesigned valve covers and oil pans and a stiffer crankcase. Sound absorbing material is also used in the interior of the engine compartment.
The ground drive system incorporates a pair of variable displacement axial piston pumps driven off the engine crankshaft through a flange coupling. The main pump assembly supplies two-speed axial piston motors located in the drive flame, along with a gear pump that powers the blade, house and boom swing cylinders. The larger KX121-3 and KX161-3 machines feature Kubota’s Load Sensing Hydraulic System which automatically adjusts the cylinder flow based on operating and load conditions.
The K008-3 and KX41-2 loaders are fitted with an adjustable track flame with widths ranging from 28 to 77 in., which Rohrbacker said allows for maneuverability in narrow passageways and confined work areas. “They’re compact machines so they fit in those spaces where you can’t fit a larger machine,” he said. “They are often in very compact places replacing manual labor.
“Sometimes the biggest machine is just too big, so that’s why we offer something all the way down to our K008-3 that is narrow enough to fit through doorways.”
Bucket capacities on the excavators range from 0.30 to 6.05 cu.ft. Optional attachments include quick attach buckets, couplers, breakers and a hydraulic thumb. A front blade is standard, with a hydraulically operated angle blade on the KX121-3 machine.
Introducing its compact articulated wheel loaders in the ’80s, Kubota’s latest models include the R420S and R520S. This new Super Series has a redesigned rounded exterior, optional factory installed cab and new 60 amp alternator for use in its core applications, nurseries, pallet fork work, landscape, rental, sewer and water projects.
Both wheel loaders are powered by liquid-cooled Kubota diesels rated 43 and 49 hp at 2600 rpm. The R420S model features the three-cylinder D1503 engine while the larger R520S is equipped with the four-cylinder V2203. Cooling systems mirror the company’s excavator line.
The loaders are outfitted with Kubota’s Load Sensing transmission. The closed-loop system is driven by a variable displacement axial piston pump off the drive shaft to two variable displacement bent axial piston wheel motors. The clutchless system features limited slip differential, four-wheel drive and a single range of speeds up to 12.5 mph.
Auxiliary functions are supplied by a charge pump and the loaders’ center point articulation is actuated through a single cylinder. “It keeps all four wheels on the ground,” said Rohrbacker. “So if you’re using them on uneven terrain, it makes sure you have good traction.” According to Kubota, the loaders have a 40[degrees] of articulation and 8[degrees] of flame oscillation.
The loaders are standard with quick couplers and bucket capacities ranging from 0.50 to 1.0 cu.yd, in all-purpose and light-duty options. Additional attachments include pallet forks and backhoes. Breakout capacity is 6550 and 7425 lb. “When you add attachments to the compact equipment, it really helps to enhance the application and often times you’re replacing manual labor,” said Rohrbacker. “You still have to get into those compact places and get the job done.”
The compact wheel loaders are manufactured at Kubota’s facilities in Hirikata and Sakai, Japan, along with the U and KX line of excavators. The company also produces a line of tractors, commercial and residential mowers as well as its most recent introduction, the RTV900 utility vehicle.
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