AutoFarm, a division of Novariant Inc. located in Fremont, CA, was developing the OnTrac2™, a new precision GPS implement steering system powered by an electromechanical drive. AutoFarm needed a solution for growers who required affordable, easy-to-install, hands-free steering on their agricultural operation. The application called for a bearing component that would run smoothly across the joints of its Mechanical Drive Unit (MDU), which has a hinged ring design that easily mounts just below the steering wheels of existing agricultural vehicles. It also had to be capable of handling the MDU's high-torque positive gear drive which controls steering wheel slippage. The bearing had to be quiet, reliable and able to withstand the high volume of dust and temperature variations it would be subjected to while in use in an agricultural environment.
The unique OnTrac2 split-gear design does not require removal of the steering wheel for installation; the unit simply latches on and off for fast, easy transfer across multiple brands and types of vehicles — tractors, sprayers, spreaders or combines. The hands-free device clamps on to the steering wheel and steers the vehicle which allows the vehicle operator to stay on task with more efficiency and greater accuracy while working in a field. The OnTrac2 provides a cost-effective solution for hands-free that eliminates skips and overlaps, lowers fuel consumption, expands the seasonal operating window, and dramatically reduces operator stress and fatigue.
AutoFarm chose Bishop-Wisecarver's DualVee® guide wheels to provide the rotary motion for the MDU. Well-known for their ability to outperform re-circulating ball technology in harsh environments due to their completely enclosed ball bearings and raceways, guide wheel systems also have other lesser-known distinct advantages. They routinely operate in environments with low noise level requirements, high (up to 500F) or low (as low as -94F) operating temperatures, washdown practices, high humidity, or very long travel lengths. They can meet flatness, parallelism and straightness tolerances as tight as ±0.001 inch (± 0.03 mm), and compared to other linear guide systems, guide wheels have less friction, are much faster to assemble, and are very cost efficient.
Bishop-Wisecarver engineers matched the component properties of the guide wheel system to AutoFarm's application to ensure trouble-free operation over the system's predicted life span, as well as reduced costs, lead time and field failures. The wheel selected must be matched to all application requirements, including environment, loads, accuracy, life cycle and cost. Bishop-Wisecarver has developed a process for ensuring the best match of guide wheel system to application, beginning with the operating environment to calculating the required wheel size.
AutoFarm chose a combination of the W1X and W2X DualVee sealed wheels for this application. The sealed wheel option is perfect for environments with heavy concentrations of liquid or fine/powdery particulates which can displace and/or change the properties of the bearing lubricant, causing premature wear and failure of the bearing balls and raceways. Specifying a sealed bearing for this operating environment aids in preventing damage to the bearing elements, ensuring the predicted life span of the system.
The DualVee wheels ride on the edge of AutoFarm's custom-made ring. Bishop-Wisecarver's DualVee technology proved to be the perfect choice for this application because of the wheels' low noise, long life capabilities and ability to traverse joints smoothly and perform in harsh environments.