Forklift Design Trends
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| Rick Honeyager |
Rick Honeyager is Director of Product Planning, Dana Off-Highway Systems. Off-Highway Systems is part of Dana Corporation's Heavy Vehicle Technologies and Systems Group. The group designs, manufactures, assembles, and markets axles and transaxles; driveshafts and end-fittings; torque converters; electronic controls; and brakes. Construction and material handling are just two of the markets Dana serves. The company is based in
Consumers and manufacturers alike demand that tomorrow's forklifts be safer and more reliable while also reducing vehicle costs and maintenance downtime. Key to accomplishing this is flexible, serviceable componentry that offers enhanced vehicle control. Many original equipment manufacturers are themselves aggressively innovating the design of tomorrow's forklifts. As such, the near future will likely favor suppliers that offer similarly innovative products to improve the speed, ergonomics, and safety of this equipment.
Independent drivetrain components
Drivetrain components that can be accessed, serviced, and replaced individually offer both service and operational benefits over the transaxle designs common today.
Separate transmission and axle systems allow each to operate in optimal environments. For instance, a forklift's axles require a high-viscosity, high-EP (extreme pressure) GL-5 lubricant, while the truck's transmission system calls for multi-viscosity, moderate-EP oil with static suppressants. Each type of lubricant serves a specific purpose to ensure the systems function optimally—providing the highest shift quality while increasing gear, bearing, and clutch life. In addition, a drivetrain with individual components enables each to be sized for the specific forklift, promoting the best possible functionality.
Separate systems can also work to reducing noise and vibration, which can affect operator comfort and performance. This is achieved by isolating the engine and transmission vibration from the operator, as the engine and axle can be mounted in different areas of the vehicle. While the axle is rigidly mounted to the frame to accommodate critical mast loads, torsinals from the engine are dampened via a separate mounting system. The result is significantly less noise and vibration throughout the entire forklift, but particularly in the operator area since the engine is not mounted to the entire vehicle frame along with the axle system.
Dana Corporation's Spicer® 137/138 axle series is designed specifically for 6- to 9-ton lift truck applications, and allows for the mast to be bolt-mounted directly onto the axle. The Spicer® TE08 transmission, scheduled for release in 2006, will complete Dana Corporation's TE series of transmissions. The TE08 is rated at 82kW and facilitates the kind of electronic control functionality forklift operators' expect. The Spicer TE08 is also planned to provide transmission clutch pack braking capabilities that allow for hydrostatic transmission simulation.
Single pedal drive
Today's operators must constantly adjust brake and accelerator pedal positions while shifting gears to hold vehicle speed. These actions distract the operator, increase the risk of accidents, and result in low machine productivity.
Innovations such as Dana Corporation's Spicer® Single Pedal Drive (SPD) product will improve the productivity of tomorrow's forklift, enabling the operator to define and maintain the vehicle's target speed automatically. The Spicer SPD is initially activated by the operator, who uses the pedal to define a target speed for the vehicle. An advanced transmission controller reads the pedal signal and interprets the operator's intent (to accelerate, decelerate, or stop), using continuously updated historical data of actual and target speeds. Also, by detecting the speed of the pedal position change, the controller can determine if the change in vehicle velocity should be smooth or abrupt. With this information, the operator's objective is then translated into control of the vehicle's driveline and brake systems.
The SPD feature automatically adjusts vehicle direction and speed, allowing the operator to better concentrate on the lifting task at hand. Control over the gear position, braking, and engine facilitates constant vehicle speed regardless of outside factors • providing uninterrupted power to the wheels. Shift quality is also dramatically improved.
Electronic controls
Tomorrow's forklift will require efficient integration of the engine, hydraulics, axle, brake, and transmission systems. Of the three distinct drivetrain solutions for forklifts today • hydrostatic (closed circuit hydraulic pump and motor), electric (battery-driven, electric motor), and hydrodynamic (torque converter with a powershift transmission) • the hydrodynamic system traditionally offers the least amount of speed control. Yet, the hydrodynamic drivetrain is a preferred solution for the future because of its robust qualities and cost-efficient price point. As such, the market is already demanding modifications for its control functions.
With electronic-control technology, hydrodynamic drivetrains can achieve a level of control comparable to that of vehicles with electric or hydrostatic drivetrain systems. Thus, a hydrodynamic drivetrain can provide the precise vehicle positioning and ground speed control necessary for applications in which high-mass loads are maneuvered with limited visibility in close proximity to people.
Electronic-control technology also allows for the engine speed and vehicle speed to be independent from each other. These capabilities offer an advanced ability for the engine system pumps to raise and lower the forks as fast as possible •without having to physically move the vehicle at the same speed.
Protecting the operator
To minimize the human error associated with forklift truck operation, tomorrow's lift trucks will also integrate protection/inhibition systems. Software with pre-programmed logic will prevent the operator from carrying out actions such as downshifting, driving in reverse, or changing direction at high speeds.
Redundancy will also become a required part of tomorrow's control system to facilitate single-point failure mode in the event of a processor malfunction. Thus, malfunction of one of the forklift's systems that is managed by the electronic controller will not cause the entire vehicle to fail.
Lifecycle management
Making many of the features described here even more functional is global positioning satellite (GPS) technology. GPS with onboard sensing helps maintain critical information about the equipment such as temperature, hours of operation, and load bearing, that with a touch of a button can be sent to a database for lifecycle analysis.
