Is it Time for a New Wheel Loader?
Better Roads Staff
As the electronic sensors become more sophisticated, they program loaders to shift smoother, which translates to less wear on the drivetrain, says Najera. “Drivetrains still have the same basic components, but it’s how you manage it. It’s now a function of the hardware and the software. Because the machine has more sensors, we have more data. We know more about them and how to make them better.”
Manufacturers are using a number of automatic transmission variations.
The Case 1021F and 1121F models, for example, have hydro-mechanical transmissions, which Case says offers the advantages of hydrostatic drive, along with the durability of conventional mechanical transmission, adjusting the mix of power delivery depending on travel speed. The hydrostatic pumps and motors work at lower speeds, mix with mechanical gears at mid-range speeds and then converts to mechanical gears in the highest speed.
Volvo says its OptiShift technology reduces fuel consumption by 15 to 10 percent over standard drivetrain configurations. OptiShift, now standard in the L150G, uses the lock-up function during a larger part of the work cycle. When an operator wants to change direction, OptiShift senses the loader’s speed, direction and accelerator position and slows down the machine by applying the service brakes automatically. This results in faster loading cycles, reduced powertrain load, smoother direction changes and lower fuel consumption, according to the company.
Lock-up torque converters have become common. Deere says they’ve had strong acceptance since the company put them on its larger wheel loaders in 2008. “They help save fuel, especially in high speed applications in load and carry,” Chesterman says. “Plus there’s a big performance benefit in ramp climbing.”
Cat’s K series drivetrains have single clutch speed shifting. The machine senses torque going through the drivetrain and will put the machine in the right gear to match demands. “This is a big change from five to seven years ago,” says Gold. “A lot of operators like to manually shift, but auto shift offers a large fuel savings.”
LCD monitors, rear-view cameras, and smoother controls top the improvements here. One example is Komatsu’s dash-7 cabs, which have a 7-inch LCD monitor panel with an easy-to- navigate menu system.
In-cab rear cameras are becoming common, assisting operators in seeing over the hood, which in some models became larger to allow room for emission reduction components. Loader controls are now electronic pilot control.
“Electrohydraulic controls have decreased in-cab hydraulic lines and increased cab space,” says Nick Tullo, product marketing specialist, Volvo Construction Equipment. Another benefit: seat-attached control units have replaced control towers. They also allow in-cab adjustments of boom and bucket detents, eliminating the need to manually adjust detents.
Cat’s 966K has low-effort electrohydraulic joystick steering system with a force-feedback feature that automatically increases joystick effort as ground speed increases. “This completely eliminates the need for a steering wheel,” says Gold. “Even though it’s an electrohydraulic system, it feels like it’s mechanically turning the machine left and right. The operator can have full control of the machine without the steering wheel.” Sensors on the lift and tilt functions allow operators to set the attachment position from inside the cab.
Manufacturers now have on-demand load sensing hydraulics. “We also offer simultaneous lift and tilt, so there’s no priority of lift over tilt, and it allows smoother operation,” Gold says. Cat, for example, gives operators the ability to set the dump height, return to dig and work tool attack angle from inside the cab. “Let’s say you’re dumping to a 5-foot conveyor. This let’s you set the dump height to 7 feet, instead of all the way to 9 feet,” Gold says.
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