Linde Material Handling has launched a new series of heavy-duty forklifts (10-ton and above) powered entirely by a closed-loop hydrostatic drive, marking a departure from the traditional torque converter and automatic transmission architecture. In heavy industrial settings, forklifts spend a significant amount of time inching forward and backward to align with loads. This constant stopping and starting generates immense heat in the transmission and wears out service brakes rapidly.
Linde's solution utilizes a variable displacement hydraulic pump connected directly to a hydraulic motor at each drive wheel. When the operator presses the accelerator pedal, the pump swashplate angles forward, pushing fluid to the motor. To stop, the operator simply releases the pedal; the pump swashplate returns to neutral, and the hydraulic fluid is forced back through the system, using the resistance of the fluid to brake the machine (hydrodynamic braking).
The engineering breakthrough lies in the "Zero-Wear" braking system. The service brakes (disc brakes) are only engaged when the machine is parked or during an emergency stop. During normal operation, all deceleration is handled by the hydrostatic drive. This eliminates brake fade and the need for frequent brake pad replacements. Furthermore, the system provides 100% torque at 0 RPM, allowing the forklift to start on steep ramps without rolling back.
Field tests in a steel distribution center showed that the hydrostatic forklifts went 18 months without a brake service, compared to 3 months for the conventional fleet. The elimination of the transmission also reduced the total fluid volume required for the machine by 30%, as the hydraulic drive system shares fluid with the lift circuit, simplifying maintenance.
