The breakthrough NuVinci continuously variable transmission (CVT) technology is a potential “game changer” when it comes to today’s transmission applications. It is a continuously variable planetary (CVP) and changes the way mechanical power is transmitted to improve the performance and flexibility of transmissions for a greener, cleaner future. NuVinci CVP technology provides improved transmission performance and flexibility in everything from bicycles, automotive accessory drives, electric vehicles, lawn care equipment to small wind turbines and beyond.
NuVinci technology, which can be manufactured at a low cost globally with standard industrial materials and processes, has been commercialized (e.g. bicycles, e-Bikes), is scalable across various applications and can be applied across a diverse array of markets and products with significant process and tooling carryover from product to product. Fallbrook has strong partnerships in place in a number of key industries providing product validation and a pathway to further commercialization.
Fallbrook and the Name NuVinci
The story of Fallbrook and its NuVinci technology dates, in a sense, to the year 1490 when Leonardo da Vinci developed a drawing describing what many believe represents how a continuously variable transmission (CVT) would work. Over 450 years later, the first real-world models of CVTs for automobiles were produced. However, various problems such as cost, scalability, efficiency and weight have kept CVTs from widespread adoption and limited their practical applications.
- Does not compromise fuel efficiency for performance
- Provides a smooth, continuous progression from one speed to another, with no abrupt ratio changes or harsh gear engagements
- Compact packaging/requires less space (lighter and smaller size)
- Flexible packaging into either U- or Thru-drive configurations
- Allows engine or motor to operate at its speed of peak efficiency or power
- High torque density
- Less complexity
- Scalable technology; can be used in a variety of applications
- Manufactured with standard materials and known processes
What Can Be Done With NuVinci® Technology
NuVinci Technology is a Platform with Diverse Applications
NuVinci technology can be used in many devices that have a transmission. That means whether you are driving your children to school, riding your bike to work, or enjoying your all-terrain vehicle on the weekend, there is a place for NuVinci technology.
The scalable technology can easily be employed in numerous applications where there is a mechanical device requiring speed changes. Fallbrook has identified the following four industries as initial markets for NuVinci technology:
- Automotive Accessory Drives
- Electric Vehicles
- Lawn Care Equipment
- Wind Energy
These industries offer high potential for early adoption by manufacturers, are substantial in size, have a history of adopting new technology, and feature companies seeking a competitive advantage through improved technology.
How it Works
NuVinci technology is a continuously variable planetary (CVP) that is based on a set of rotating, tilting balls fitted between two rings. Figure 1 illustrates the basic components of the NuVinci CVP technology. As shown in Figure 1, the NuVinci technology has:
- an input disc, or ring, driven by the power source.
- an output disc, or ring, connected to the CVP output
a set of balls each rotating on its own axle and fitted
between the input disc, output disc and a central “sun”
to help maintain the balls in position
Torque from an engine, motor or other input source (illustrated in Figure 1 by the blue line at the top with arrows going left to right) is transferred through the input disc to the balls using a thin layer of traction fluid.
The torque is then transmitted through the balls to the output disc. via another thin layer of traction fluid. The input disc and output disc are “clamped” onto the balls tightly so that the requisite amount of clamping force is provided for the amount of torque being transmitted. However, as indicated above, torque is transmitted through the traction fluid, which prevents destructive metal to metal contact between the balls and discs while providing traction for the balls and rings and lubrication for bearings and other components.
The speed of the output disc compared to the speed of the input disc, or speed ratio, is controlled by the angle of the ball axles relative to the axis of the transmission. Figure 2 illustrates that tilting the ball axles shifts the transmission from low to high (as shown left to right), or from high to low, or to any ratio in between. The number of balls used depends on several factors including torque and speed requirements, operational requirements and space considerations, among others.
How is NuVinci® Different?
Unlike conventional transmissions that have a fixed number of gear ratios, a continuously variable transmission (CVT) has an unlimited number of ratios within its particular ratio range from low to high. The use of a CVT compared to a conventional transmission facilitates operating the power source at an optimum speed, which usually occurs where the power source is either most efficient or is producing its highest power or torque. While the power source is typically an engine or motor, it can also be human power, as in a bicycle.
When used in an automotive transmission, CVTs improve performance by allowing the engine or motor to continuously deliver peak power to the drivetrain while steadily allowing the speed of the vehicle to increase through acceleration. When power demands are below peak levels, the power source is allowed to operate at its most efficient possible condition for the power level demanded by the user. This also improves efficiency by allowing the vehicle’s engine to operate at or near its most efficient speed while vehicle speed varies.
By allowing engines to operate at their most efficient speed when the highest power isn't needed, the CVT optimizes the overall system efficiency, reduces fuel consumption and emissions and their associated adverse effects on the environment. Besides automobiles, the potential benefits of CVPs are similarly applicable to many other mechanical systems that require variation between the speed of a primary drive and the speed required to operate the mechanical system.
NuVinci is unique among CVTs in that it is, in technical terms, a compound variable planetary “drive.”