Is this some new competition for the Rohloff?
The patented NuVinci technology developed by Fallbrook Technologies Inc. (Fallbrook) is the most practical, economical and universally adaptable continuously variable planetary (CVP) transmission for human-powered and motor-powered vehicles and machines. The NuVinci CVP is ideally suited for applications in many major industries including bicycles, light electric vehicles, tractors, automobiles, trucks, and utility class wind turbines among others.
The NuVinci transmission uses a set of rotating and tilting balls positioned between the input and output components of a transmission that tilt to vary the speed of the transmission. Tilting the balls changes their contact diameters and varies the speed ratio. As a result, the NuVinci CVP improves acceleration, performance and efficiency over conventional transmissions. The NuVinci CVP offers seamless and continuous transition to any ratio within its range, thus maximizing overall powertrain efficiency, with no jarring or shocks from the shifting process.
When compared to traditional continuously variable transmissions (CVTs), the NuVinci CVP is less complex, has considerably fewer parts, offers more stable control, is easier to shift, offers more scalability across product lines, is better packaged, and is less expensive to manufacture and assemble.
Distinguishing the NuVinci CVP from Traditional CVTs.
There is a clear distinction between Fallbrookâ€™s NuVinci continuously variable planetary drive (CVP) and more traditional continuously variable transmission (CVT) technologies.
A CVT is a transmission that is infinitely variable between its high and low range as opposed to a conventional geared transmission where the number of speed ratios between high and low is limited by the number of gears.
The CVT has been called the â€śholy grailâ€ť of transmissions because it eliminates the multiple gears, shifting clutch and many other parts found in conventional transmissions. In place of gears, most CVTs use one or more cones, discs, balls, toroids or other alternative shifting devices. These geometric shapes allow the contact points on the shifting device to vary in diameter, thus changing the input to output speed.
The use of CVTs has not become widespread due to multiple problems inherent in traditional designs. These problems include shifting control difficulties, poor efficiency, scalability challenges, questionable reliability and durability, high cost, and other factors.
The NuVinci CVP represents a quantum leap forward over traditional CVTs as well as conventional mechanical transmissions. These advantages include:
Higher torque density
More adaptable and versatile
Improved overall performance
Easy to package (less space required)
Lower manufacturing and maintenance costs
How the NuVinci Transmission Works
The NuVinci CVP is continuously variable and infinitely applicable to almost any product using mechanical power transmission. NuVinci technology combines the advantages of a toroidal traction CVT with the time-proven versatility of the planetary gear arrangement. It uses rolling traction to transfer torque, just as toroidal transmissions do. However, unlike toroidal CVTs, it distributes the transmitted torque over several spheres in an inherently stable configuration, thus lowering contact pressures and significantly improving durability, control stability, and torque density.
This arrangement makes the NuVinci transmission the only practical CVT to combine the smooth, continuous power transfer of a CVT with the utility of a conventional planetary gear drive. Torque inputs can be summed or divided, just as in a conventional planetary. Ratio control is stable, and can be actuated down the center line of the transmission, again similar to the proven planetary transmission. Part shapes are simple and easy to manufacture. And in most applications, there is no need for power-robbing, high-pressure hydraulics.
The NuVinci CVP reduces fuel and/or energy consumption due to its high efficiency and seamless speed changing characteristics, allowing the power input such as an engine to operate in its most efficient speed range. Overall, the NuVinci CVPâ€™s mechanical and manufacturing efficiency improves performance and reliability while reducing costs over conventional CVTs and stepped transmissions.
As a result, the NuVinci CVP can potentially replace the planetary gear automatic transmission in most mechanical devices.
Key advantages of the NuVinci CVP
Compared to conventional transmission technologies, the NuVinci CVP provides:
Less complexity. There are significantly fewer parts than conventional transmissions and it is much less costly to manufacture.
Overall improved system efficiency. With the NuVinci CVP, it is easy to keep an engine running at its most efficient speed.
Greater acceleration and optimum performance. Acceleration is faster and smoother â€“ right up to the vehicleâ€™s acceleration limits â€“ because it keeps the engine running at peak performance.
Easier shifting. There is no jarring associated with shifting gears.
Ability to accept multiple inputs while varying speed and ratio, managing torque and providing multiple power outlets. A NuVinci transmission is the most practical CVT technology to perform all of these tasks simultaneously.
Support for a torque demand rather than a speed demand control solution. The NuVinci CVP solves the low-speed acceleration problem inherent in some torque-demand vehicles.
Scalability and potential to reuse tooling. The technology is highly scalable. The design and implementation of a low-torque application utilizing four balls may involve the same basic parts as a higher torque application with eight or sixteen balls. Also, tooling can be used across a wide variety of applications.
Compared to CVT alternatives, the NuVinci CVP offers:
Coaxial input and output. The input and output shafts are in-line, making the transmission simpler, smaller, easier to package, and lighter.
Better torque density. A NuVinci CVP delivers a large amount of torque in a small space. It is smaller and easier to package than CVTs because it does not require an offset shaft and because it can spread torque across any number of balls.
Lower manufacturing cost. The transmission uses simple geometry and very simple parts which results in a lower cost. The NuVinci CVP can also be scaled across a wide variety of vehicles in many cases without retooling.
Lower control cost. Transmission control is stable, linear and does not require a major control system development effort.
Power path variability. The technology is easily integrated into a wide range of applications with varying power path requirements or options.
Scalability. The NuVinci CVPâ€™s simple design and low part count make it easily scalable.
Technology Applications for NuVinci technology
While the NuVinci CVP has application potential in virtually any mechanical device requiring speed variation,. Fallbrook has initially identified six major industries for licensing of NuVinci technology:
Light electric vehicles (LEVs)
All-terrain vehicles (ATVs)
Fallbrook selected these initial industries because they offer:
High potential for early adoption by manufacturers
Large market size
Potential rapid time-to-market
Companies seeking a competitive advantage through improved technology
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