E-bikes: generating cash for automotive CVTs

 A growing market for E-bikes, especially in Europe, is helping generate cash for Fallbrook Technologies Inc. as it develops its NuVinci continuously variable transmissions (CVTs) for automotive, off-highway and industrial applications

Recognising that building up the 2,000,000km durability requirement expected – and demanded – by commercial vehicle manufacturers can take a long time, Fallbrook Technologies is adopting a four-pronged attack to the problem.

The four-pronged attack comprises two-wheel vehicles like bikes and E-bikes, passenger cars and light truck, heavy commercial and off-highway vehicles and finally industrial applications. And for these areas it has three licensees all of which are working actively in a range of transmission applications.

The first and the last of these four areas are likely to provide the launch pad for further growth in the other two areas. Relatively cheap to manufacture, CVTs for E-bikes offers the necessary manufacturing experience for high-volume production. Typically, the numbers are in the region of 100,000 a year – a figure recognised by the automotive world which understands the unique environment of process control and supply chain management.

The industrial units, for conveyors and other industrial units could be manufactured in lower volumes but pave the way for higher horsepower applications. This area of Fallbrook Technologies' expertise is being developed by Team Industries Inc. of Bagley, Minnesota, itself a licensee of Fallbrook Technologies' NuVinci CVT.

Next in line, and with a shorter time to market, is likely to be the recreational/small vehicle/utility vehicle sector. Here the volumes are not as large as passenger cars but they further help pave the way to wider application. This product sector is being addressed by one of Fallbrook's licensees.

Addressing another sector, Dana Holding Corporation of Maumee, Ohio is a licensee of the NuVinci technology with direct application to light-duty trucks and passenger cars.

Such is Dana’s commitment to the technology that late last year it announced a Technology Centre in Cedar Park – exactly where Fallbrook Technologies is based. Dana is receiving $1.25 million in funding from the Economic Development Department for Cedar Park, Texas, to help set up the centre.

In setting up the centre, Dana noted that it will “fully leverage” the company’s investment in its strategic relationship with Fallbrook Technologies Inc.

In September 2012 Dana secured an exclusive license from Fallbrook Technologies to engineer and produce “continuously variable planetary” (CVP) technology for use in light vehicles and certain off-highway transmissions.

Dana clearly is hoping a place will be found for the CVP in the passenger car and light trucks arenas.

The final leg of the stool – involving Allison Transmission Inc. – another licensee – is the one which is most difficult to satisfy. Its demands are high – the request for 2,000,000km durability requirement from some truck OEMs being just one of them. Another requirement is the need to cope with high torque inputs – 1,000Nm being just one number of many associated with this type of transmission.

And it is in aiming to satisfy this market, eventually, that Fallbrook Technologies is pursuing the other market areas to build up all the necessary areas of expertise.  

As well as providing manufacturing and durability experience, the E-bike market – which in Europe is worth 1.6 million units annually – is providing the baseline numbers that automakers and OEMs recognise.

Fallbrook Technologies already claims to have sold over 100,000 bike and E-bike NuVinci CVP transmissions and the market is growing.

The E-bike market is also offering a launch point to move into the moped and small motorcycle market. These too will provide the additional annual numbers that help to give automakers and OEMs the confidence the transmission – based on “moving from gears to spheres” are looking for.

Fallbrook Technologies has more than 45 people developing a range of CVT prospects as well as developing the technological baseline suitable for further growth. In its partnering, Fallbrook has developed a “community” for the technology through its licensing. Improvements to the technology are shared among the members of the community to improve quality of designs and speed the development cycle for the members of the community.

Already developing transmissions of “several hundred kilowatts” capability, the engineers are gradually, through extensive durability trials, building up the necessary simulation tools that will lead eventually to the 2,000,000km goal.

“We have been investing heavy in testing based on the coefficients we have already obtained,” noted Alain Charlois, executive vice president, corporate and business Ddevelopment of Fallbrook Technologies Inc. in an interview. “And that is why we are getting a lot of attention from automakers, OEMs and Tier 1 automotive suppliers. They are not questioning that the technology works or that it brings improved fuel consumption, or reduced energy use for other applications.”

As Charlois sees it, the “direct sell” element derived from bike/E-bike CVP transmissions provides the steady cash-flow incomes needed to keep the company going. Licensing provides further valuable income while the next level of cash inflow will be derived from the commercialisation of CVPs in the recreational/small vehicle market and the sale of low volumes CVPs for industrial applications in the non-transportation arena.

Applications in the auxiliary drive field could provide further encouragement for growth and in this respect Fallbrook Technologies hopes to make an announcement shortly. These are likely to have multiple applications in both automotive and off-highway spaces and could involve several Tier 1 automotive suppliers

Charlois is wary of revealing any numbers that might lead anyone to unravel the size of the business, or the extent of the level of investment so far. Nor is he willing to disclose customers, the size (in terms of horsepower or torque) of the various CVP traction drives under development that might incriminate him in any non-disclosure agreement – of which Fallbrook Technologies has many.

“All of our partners are very sensitive the release of information,” is all he will say.

But it is known that serious automotive numbers have to begin at 50,000 units a year.

It is clear that the E-bike market with its 250kW electric motor drives and associated CVP transmission could lead before long to 350kW and thence to 500kW applications if regulations change. The market for E-bikes in Germany is worth 900,000 units a year alone and could swell.

This technology leads on immediately to mopeds and small recreational vehicles and thence into passenger cars.

Experience thus far with CVTs suggests the road ahead is not easy.

“Nothing will kill you quicker than turning up with a transmission that does not meet customer requirements,” said Charlois.

He is hoping the road Fallbrook Technologies is taking will lead to that elusive pot of gold at the end of the rainbow.

                                           How NuVinci works

NuVinci technology is a continuously variable planetary (CVP) system based on a set of rotating, tilting balls located between two rings. The basic components  comprise an input disc, or ring, driven by the power source; an output disc, or ring, connected to the CVP output; and a set of balls each rotating on its own axle and situated between the input disc, the output disc and the central ‘sun’ that maintains the balls in their position.

Torque from an engine, motor or other input source 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 through another thin layer of traction fluid.  The input disc and output disc are compressed onto the balls by an external force. The value of this force is proportional to the torque being transmitted.  

The torque is transmitted through the traction fluid which prevents destructive metal-to-metal contact between balls and discs whilst at the same time 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.  Tilting the axes of ball shifts the transmission steplessly from low to high, 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.

The overall speed (torque) ratio that can be achieved from the CVP variator components alone is 4:1 or 400 per cent, but this can be expanded or reduced through configuration of the entire transmission to meet the needs of the overall system. Extending the technology from bikes through to heavy commercial vehicles is certainly a challenge not to be undertaken lightly.

Finally, in an interesting twist of irony, Torotrak plc on its web page under the heading "Driving change" recently highlighted its new and “unique” traction drive elastohydrodynamic fluids laboratory. Following its own short video clip of the laboratory, Torotrak highlights the work of various other CVT, IVT and transmission innovators using YouTube video clips.

One video clip is from Fallbrook Technologies Inc. entitled an "Introduction to NuVinci CVP"; another is: "How a CVT works" by Team Industries Inc.∎

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