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This file type includes high resolution graphics and schematics when applicable. | One of the great advantages of hydraulic drives is the absence of axles that would otherwise traverse a vehicle’s undercarriage. Hydraulic drives allow designers to place more mass between the wheel centers, rather than above them. The result is a lower center of gravity, which makes the vehicle more stable on uneven ground. Another big plus for hydraulics is independent drive control. Speed, torque, or power can be directed to individual wheels to match the specific ground conditions. The result is optimum traction control. Keeping wheels engaged with the ground gives the operator greater control and helps keep loads from shifting.
Matteo Michelin, of SAI Hydraulics, Modena, Italy, expands on these concepts with five factors that should be considered when designing a safe, compact, and efficient hydraulic drive:
Center of gravity—A compact hydraulic motor keeps the drive’s center of gravity lower than with purely mechanical drive trains, resulting in high stability, even when operating on very steep slopes. The vehicle’s overall performance is thereby improved, and the risk of overturning reduced.
Furthermore, a drive layout using hydraulic wheel motors allows greater flexibility of cabin design and engine placement, resulting in more flexible equipment designs and greater comfort and safety.
Traction distribution—Distributing traction means simply transmitting the available torque to the ground in the most efficient way possible. Flow dividers or connecting motors in series are not the most efficient methods for preventing a wheel from spinning, nor do they give the fastest reaction times.
