Cover Story: Wheel loaders 90 to 120 net horsepower
| June 12, 2007 |
Smaller loaders with z-bar linkages are a mainstay on jobsites around the country. They are unmatched in load-and-carry applications ranging from earthmoving to logistical support work. Their front ends give them the high breakout forces they need to root into tough material stockpiles, but are versatile enough to handle a wide range of attachments when fitted with a quick coupler.
Innovative cooling system optimizes weight, reduces maintenance
· Modular, mid-mounted cooling system · One-piece, flip-up rear hood
· Ground-level, grouped maintenance check
· Remote engine/cooling/hydraulic drain points
· Bucket control-mounted, forward/neutral/reverse shuttle switch
Case manufactures one model in the 90- to 120-net-horsepower class. Its 521D loader debuted in March of last year and immediately made a mark thanks to its innovative cooling system design. “It’s called a mid-mount cooling system, and it’s all-new,” says Dave Wolf, wheel loader marketing manager. “On conventional wheel loaders, coolers are stacked on the rear of the machine. But on the 521D, these coolers are mounted right behind the cab.”
Wolf says the coolers are arranged in a box shape, yet each is independently mounted on the outside of that box. “The cleanest air in most wheel loader applications is found right behind the cab,” he explains. “You do get some dust kicking up off the front tires, but overall, it’s about the cleanest air you’re going to find around the machine. This air is what is ingested by the 521D to cool all of the fliuds.” And, Wolf says, because this air is cleaner, the 521D benefits from a measurable decrease in engine and cooling system contamination and contamination-related failures.
“We went to a hydraulically driven fan,” Wolf adds, “included in the box cooler arrangement.” The highlight of this feature, according to Wolf, is that you can easily reverse the fan flow from the operator’s seat. “So if you do get some debris built up on those coolers, you simply reverse the fan’s flow and let the coolers purge themselves,” he says. “You don’t have to leave the cab and go find a pressure washer or a compressed air line to clean them out.”
Case also worked on the front end of the 521D, raising the hinge pin height to give more clearance and better bucket rollback characteristics. “And we improved the bucket design by adding a tapered floor in the bottom and extending the leading edge so that it penetrates more like a knife when you push into a pile,” Wolf says. “We also tweaked the transition to the tapered area so that the bucket fills and dumps better.”
Cat hystat, torque converter models meet several applications
· Load-sensing hydraulic system
· Hydrostatic transmission with two drive speeds (914G)
· Lift/tilt kickout neutralizer
· Front and rear limited slip differential
· Waste-handling package
Cat’s G Series wheel loader family includes three models in the 90- to 120-net-horsepower classes. The 914G is the smallest of the three. “It’s a hydrostatic drive machine,” says Mike Perez, commerical manager. “There’s no gear selection to worry about and you get smooth, variable power throughout your horsepower range. They’re also very efficient for use with front end attachments.”
Still, Perez says Caterpillar recognizes there are shortcomings with hydrostat wheel loaders in some applications. “Hydrostatic drives are not efficient in extensive load-and-carry work applications because they become less effective as the travel speeds increase,” he says. That’s why Cat designed its 924G and 924Gz loaders with torque converter transmissions. “It a natural fit since these loaders give you the same type of aggressive in-pile characteristics as a hystat machine, but faster top end travel speeds,” Perez says.
Although there will be no G Series upgrades until Tier II emissions standards take effect, Perez says Cat recently introduced a waste-handling package for severe cleanup applications. “It features specialized cooling options, guarding packages and attachments,” he notes. “One nice feature is the reversible cooling fan. This allows the operator to stay in the cab and clean his intake screens out simply by pushing a button. So it simplifies a common maintenance problem in an unpleasant environment and also contributes to longer machine life by preventing engine overheating due to poor air circulation.”
Dash V loaders offer more in-cab comfort, improved visibility and ZF transmission
· New cab and revamped HVAC system
· All-automatic ZF transmission
· Attachment-ready, hard-wired electrical system
· Higher horsepower Daewoo engine
· Torque-proportioning differentials
Daewoo’s entire Mega wheel loader line received significant feature enhancements this year with the introduction of its Dash V models, which replace the company’s previous Dash III line.
With these changes, Daewoo’s Mega 160-V loader fits in this month’s Selection Guide classifications. The Mega 200-V, which was in this class as a Dash III model, has received a horsepower increase and moves up one size class as a result.
According to Brian Sheely, product manager, Daewoo took its existing Mega wheel loader platform and added a new cabin with approximately 10 percent more interior room. “We’ve added additional glass to improve visibility in all areas” Sheely adds, “and the heating and air system has been completely redesigned for a 150 percent increase in climate control.”
One new important feature on the Mega 160-V loaders is the addition of all-automatic ZF transmissions. “In the past, we only offered ZF units on our larger wheel loaders, but now they are standard throughout the line,” Sheely says. The transmission has four forward speeds, and three in reverse. You can operate it either manually with the forward/reverse lever, or automatically. The transmission senses torque requirements and shifts to meet them. So you don’t have to worry about downshifting manually when you’re digging into pile. Sheely says with the new transmission, Dash V loaders now have a maximum ground speed of 23 mph forward and 15 mph in reverse.
Also new are outboard, wet-disc brake types and torque-proportioning differentials. “This brake system not only actuates the service brakes on all four planetary drives, but it also disconnects the transmission when necessary,” Sheely notes. “If you want to divert 100 percent of the machine’s available horsepower to the hydraulic system when you’re in a pile, all you have to do is step on the brake pedal. The transmission will immediately shift into neutral, giving you the extra boost to power through a tough spot.”
Deere 444H Smart-shift technology shifts smooth, regardless of application
· Stereo steering (rear wheel articulation) (344H)
· Hydrostatic transmission (344H)
· Smart-shift technology (444H)
· Improved ride control system (444H)
Deere has two loaders in the 90- to 120-net-horsepower classes, the 344H and 444H models. “The 344H is a bit different in that it features stereo steering to make it an extremely maneuverable machine,” says Andrew Bonde, business analyst manager. “This system gives the front of the 344H 56 degrees of conventional loader articulation. But the rear wheels can also steer up to 29 degrees and are tied in mechanically to match the front end’s articulation angle. The overall effect is a machine with a steering profile equivalent to a conventional loader with 96 degrees of articulation.”
Bonde notes the 344H features a hydrostatic transmission with infinitely variable speed control over the loader’s full operating range. “This transmission features low-effort, electric shifting,” Bonde says. “A single, twist-grip lever control handles gear and direction changes and an HST-inching pedal allows you to infinitely reduce travel speeds while maintaining full engine rpm and hydraulic flow.”
Deere has also improved the 444H’s ride control feature this year. Bonde says it is now even more effective at smoothing out the ride during heavy material transportation. Unlike the 344H, the 444H has a torque converter, Smart-shift transmission. “It’s computer controlled,” Bonde says, “so you get smooth gear shifts under any power conditions. It gives you full electronic control over each clutch pack via a twist-grip shift lever. You can also opt for full automatic shifting between first and fourth gear or second and fourth gear.”
Dressta’s torque converter transmission matches power to the application at hand
· Countershift transmission with constant gear mesh
· Optional tool carrier package with quick coupler
· Komatsu diesel engine
· Pressure-compensated, dual-pump hydraulic system
Dressta’s E wheel loader line appeared in September 2001, and includes the 510E model. Among the upgrades from the previous “C” loader family are a new, automotive in-cab styling and a factory-mounted air conditioning system. “The E series is the fourth generation of this loader line,” says Dick Middlecamp, marketing manager. “We use robust axles designed with inboard, wet-disc brakes, a powershift, modulated transmission /torque converter module and our own pressure compensated dual-pump hydraulic system. We power this package with a high-torque-rise Komatsu diesel engine. It’s a simple, highly efficient powertrain.”
Middlecamp says the torque converter features a three-element, single-phase, single-stage design that automatically modulates engine power through a fluid coupling control system. “This system effectively matches engine power to the load and absorbs drivetrain shocks, reducing operator fatigue,” he says. “The countershift transmission module is adjustment free and uses a minimum amount of wearable parts.”
The heavy duty axles on the 510E are engineered to withstand heavy loads and stresses in all types of loader operations. “All four wheels on the E series use completely sealed and adjustment free multiple oil-disc brakes,” Middlecamp says. “This system combines with two independent hydraulic brake circuits (one for the front wheels, one for the rear wheels) for added reliability in tough applications,” he says.
Gehl enters wheel loader market with all-wheel steer, telescoping boom Kramer machine
· Standard four-wheel steering
· Optional telescoping loader boom
· Vibration-isolated, ergonomic cab
· Hydrostatic drivetrain
Gehl and its subsidiary Mustang are newcomers to the North American wheel loader market, but their product is not. The company has been appointed the exclusive distributor for the Neuson/Kramer Allrad wheel loader line, which Larry James, marketing manager, says is the best selling wheel loader in Germany. Gehl has redesignated Kramer’s 720 loader as the Gehl/Mustang 721. It will begin appearing at dealerships this summer.
“The 721 is a highly specialized design,” James says. “The ‘Allrad’ designation stands for ‘all-wheel radius.’ The 721 model loader differs from other machines on the North American market in that it does not have an articulating front end. Instead, all four wheels turn, either in counter-steer or crab-steer modes, depending on the operator’s input or jobsite conditions.”
James says that like all Kramer loaders, the 721 is offered in two basic linkage configurations: either with conventional z-bar or telescoping boom. “The telescoping boom gives you unprecedented forward reach when loading or using attachments in difficult-access applications,” he says.
High-strength frame resists shocks
· Centralized electronic monitoring system
· Cummins diesel engine
· High-rigidity frame
· Dash-mounted transmission monitoring system
The Hyundai HL730-3 wheel loader uses a high rigidity frame to support the powertrain and front loader in tough applications. It features reinforced, sealed, loader linkage arms for added durability to resist loading stress and shock.
The cab rides on isolation mounts to minimize internal noise and vibrations. A single-shift lever on the left side provides you with fast, easy control of the loader’s speed and direction. Two kickdown switches on top of the loader control lever and transmission control lever allow you to instantly reduce gears when additional tractive effort is needed. Kickdown mode can be set to automatic or manual mode, depending on the operator’s preference.
To further increase productivity in load-and-carry operations, the HL730-3 comes standard with a bucket positioner and automatic boom kickout. The bucket positioner allows the operator to preset the bucket’s level position after dumping a load for fast entry back into a pile. When you’re repeatedly dumping loads at a consistent height, the boom kickout feature automatically raises the bucket and stops it at the predetermined height.
Ride control cuts wear and vibration on Kawasaki ZIV-2 wheel loaders
· Cummins B3.9C diesel engine
· Torque-proportioning differentials
· Massive center pins and bearings
· Three-speed countershift transmission with powershift
Kawasaki bills itself as a loader specialist. And it’s a justifiable statement since the company has been designing, building and selling only wheel loaders in North America for more than 35 years. Currently, Kawasaki offers two models in the 90- to 120-net-horsepower classes: its 50ZIV-2 and the larger, more powerful 60ZIV-2.
“Our loaders come with the heaviest Z-bar linkage arms in their class,” says Gary Bell, vice president. “These heavy-duty arms give you high breakout forces regardless of application. We also equip our machines with single-lever hydraulic controls and single, twist-grip transmission controls to make operating our machines as easy as possible.”
An automatic boom height positioner and bucket leveler function are standard, as is a 1.7-cubic-yard bucket. Bell says the bucket design is optimized for easy loading and excellent load retention and can be configured with a wide assortment of edges and teeth. Kawasaki engineers also added standard heel plates to extend bucket life, even in tough, rocky work conditions.
Komatsu ups WA-180-3 horsepower
· Increased horsepower (WA-180)
· Larger standard buckets
· Spin-on type filters and see-through fuel strainer
· Automatic four-speed transmission
· Improved ride control system
Komatsu’s two 90- to 120-net-horsepower loaders are the WA-120-3 APlus and the WA180-3 Advance Plus models. According to Mike Goche, product manager, the WA-180 has received several enhancements for the 2002 model year.
“For starters, it’s a more powerful machine,” Goche says. “Its engine output rating has gone up, from 110 to 120 horsepower, and we also increased its standard bucket size from 2.1 to 2.9 cubic yards. We also increased hydraulic power for more lift capacity.”
Also new is a four-speed, electronically controlled, automatic transmission and pilot pressure controls (PPC). “The new transmission eliminates the constant shifting the load-and-carry operations can demand from an operator,” Goche adds. “And the PPC control system gives precise control over the boom arm and bucket. These features, and the WA-120 and WA-180′s new 21.4 mph top travel speed, give a high-production machine that doesn’t wear the operator out by the end of the day.”
Standard torque proportioning axles for assured traction in slippery jobsite conditions
· Torque converter drive transmissions
· Torque-proportioning axles
· Standard, attachment-ready third hydraulic valve
· Standard air conditioning and air ride seat
· Grouped, ground-level maintenance checkpoints
New Holland’s LW90 and LW110 wheel loaders were launched in 1999 and will receive no major upgrades for the 2002 model year. Sam Wyant, wheel loader marketing manager, says both machines share the same design, which includes mechanical torque converter drive transmissions. “Most loaders in the 90- to 120-net-horsepower classes are equipped with hydrostatic transmissions,” Wyant notes. “But we feel hydrostatic drives can impose limitations on the machines – most notably a limited top speed. Our transmissions combine the best of both worlds by giving you good hydraulic performance and fast cycle times.”
To further enhance LW series’ productivity, torque-proportioning axles are standard on both models. “They give you torque transfer in slippery conditions,” Wyant says. “If one wheel begins to slip, the axle will automatically transfer power to the other wheel for extra traction.”
Z-bar linkage is standard for both the LW90 and LW110, as is a third hydraulic valve. “This third valve allows you to easily hook attachments to the front end of the machine and put them to work since the plumbing is already in place for a four-in-one bucket or a broom,” Wyant adds.
Wyant says all New Holland loaders feature standard air conditioning and air ride seats, which he says is unusual in smaller loaders like the LW90. “We provide you with 50 square feet of glass,” he notes, “and seamless lines of sight to the bucket and sides of the machine.”
TP linkage offers z-bar breakout forces and toolcarrier style attachment versatility
· Care Cab II ergonomic package
· Enhanced HVAC system with recirculated air filtration
· Contronic II loader function monitoring system
· Patented TP front linkage system
· APS II automatic shifting system (L70D)
Volvo has three machines in this month’s category: the L45B, L50D and L70D. The L45B is a more compact loader than the L50D and L70D, and belongs to a different model family.
Dan Snedecor, wheel loader product marketing manager, says the L50D, despite being the smallest example of Volvo’s D Series, shares many of the same design features as its larger counterparts. “It has a torque converter but a hydrostatic transmission with a clutch pack,” he says. “This gives it quick acceleration and continuously variable speed control without the harshness of hydrostatic drive. The L50D can maximize power and flow to attachments even while operating at very low travel speeds.”
Volvo components used throughout the machine make them highly efficient. “If you look at the specs on our gross and net horsepower ratings, you’ll see that they’re very close,” he notes.