When Kubota decided to design its own utility vehicle, it stuck to what it knows best – tractor technology – to give its new RTV900 rugged durability. “We know how to make tractors, so we took a tractor transmission and engineered it to work in a utility vehicle,” says James Burnside, product manager for utility vehicles.
The variable hydraulic transmission or “VHT” developed for the RTV900 is actually a unique, two-stage hybrid of a tractor transmission and Kubota’s load-sensing wheel-loader transmission. “Our tractors are designed for lugging and pulling, but at a top speed of 15 mph,” Burnside says. “In a utility vehicle you need to go 25 mph. So we gave it a second hydraulically driven motor that kicks in to give you a little extra power when the load reaches a certain point.” As a result the RTV900 can run at 25 mph and not lose its lugging capability.
The VHT also gives the machine dynamic braking. Letting your foot off the gas pedal creates hydraulic resistance and slows the vehicle independent of the service brakes. This reduces wear and tear on the brakes and prevents the machine from freewheeling downhill. The no-clutch transmission offers three ranges: low, 0 to 9 mph; medium, 0 to 18 mph; and high, 0 to 25 mph. The front and rear wet-disc service brakes are sealed from contaminants and wear resistant.
To facilitate easier steering, Kubota engineers used a hydraulic steering cylinder rather than rack-and-pinion gears. The hydraulic power steering becomes more important the heavier the vehicle gets, Burnside says. “If you put a blade or a cab on it, steering with a rack-and-pinion design would get harder. With power steering it’s just like steering your car – you can do it with one hand.”
Another automotive-like feature is the suspension system – independent McPherson-type struts up front and semi-independent suspension axle with leaf springs and shocks in the rear. “The obvious benefit is that it provides a smooth ride,” Burnside says. “But it’s also for better traction. With a fixed front suspension if your right tire were on a log, your left tire would be in the air too. With an independent suspension the left wheel helps pull you over the log.”
The Kubota RTV900 will be available in February 2004 and comes in general purpose, recreational, turf and worksite cofigurations.
Redesigned excavator features fold-down ROPS
A new design incorporated into the K008-3 ultra-compact excavator is the fold-down ROPS. In a few seconds, the operator can unpin the top half of the ROPS and fold it down to a height of 5 feet 11 inches. This helps plumbers, utility contractors, landscapers and building contractors work around and maneuver under low eaves, gates, tree limbs and doorways, says Keith Rohrbacker, product manager, construction equipment.
The dash-3 version also includes a two-speed travel system with a top travel speed of 4 mph and a working speed of 2 mph. “It’s rare that you’re able to bring your trailer right there next to where you trench,” says Rohrbacker, “so this really helps productivity.”
A two-pattern selection system lets you switch the joystick control from ISO to an SAE-type control pattern, so if your operator is more comfortable working a backhoe’s controls he can select the same pattern on the excavator. Kubota also added double-flanged lower track rollers to increase stability and reduce bouncing. Legroom on the deck has been extended 4.2 inches for more operator comfort.
New pump on KX41-3V improves productivity
The big news on the KX41-3V excavator was the replacement of the gear pump with a variable-displacement piston pump. “You get faster operating speed when you’re lightly loaded and it automatically converts to more power when it’s heavily loaded,” says Rohrbacker. “On a 1.5-ton machine the smoothness of the front working group is important so that it doesn’t bounce around.” The variable-displacement pump requires less horsepower, so Kubota downsized the engine, which increased fuel economy and allowed engineers to move the seat back for a roomier operating environment.
The redesign also optimized weight distribution and track length to reduce machine bounce and operator fatigue and improve stability and lifting capability. The travel speed switch was moved from the floorboard to the top of the blade control lever to free up additional footspace on the floor deck.
A new backlit digital monitoring panel allows you to check engine functions and also prompts the operator when scheduled service is due. During refueling an alarm on the panel beeps when the fuel tank is nearly full to reduce spillage.
Angled blade makes quick work of backfill
The 2-ton Kubota KX121-3 was the beneficiary of a small feature with big implications for jobs where backfilling is done. Engineers put another cylinder on the backfill blade so that it can be angled 25 degrees to the right or left. This allows operators to backfill a trench in one pass rather than repeatedly pushing dirt with a fixed blade and then backing up and coming at it again from another angle.