Introducing the RADIALcvt Gen II

Varibox is very excited to officially announce the RADIALcvt Generation II, which introduces significant design improvements to the already splendid RADIALcvt Generation I gearbox. The Generation II RADIALcvt was designed based on the successfully tested initial RADIALcvt, which broke the 90% efficiency barrier and now serves as benchmark for further application development.

The Concave and Convex disks of the Generation I RADIALcvt were replaced by two flat disks, which resulted in the elimination of the combining planetary system which was required in the Gen I design. Flat disks are also easier and more cost effective to manufacture.

In the Gen I design, ratio adjustment was dependent on the Convex and Concave disks, while in the Gen II design, ratio adjustment is done in a direct fashion via a Ratio spiral cam. This feature also allows for increased ratio shifting speed while providing precise control over the position of the 3 traction Drivers.

Using the typical Gen 1 design the ratio range can be extended to about 4.7, which is sufficient for small vehicles, however larger vehicles, typically passenger, hybrid or ICE (Internal Combustion Engine) vehicles require a ratio range of up to 10, which typically include the current 9 and 10 speed automatic automotive transmissions.

The challenge for current commercial CVT, including the RADIALcvt, is to extend its basic range to a ratio range of 10 in a synchronous way and ideally without any power interruption. Currently such dual mode synchronous systems are realised by utilising a planetary powersplit configuration with the downside of multiple wet clutches as well as circulating power and torque which has a negative effect on transmission efficiency.

The RADIALcvt Gen II solves this problem by utilising a novel 3-mode synchronous system in which the second mode is a direct drive bypassing the variator and therefore presents a very high efficiency mode. While this second mode is engaged the variator can shift to the required ratio range end to allow for a synchronous shift. This 3-mode synchronous system is realised with a single dog clutch with multiple positions which simplify the selector automation very significantly.

Please watch the following video which describes the RADIALcvt Gen II in more detail

Also, Varibox has placed an article in the latest Transmission Technology magazine. You can read this article by following this link.

For further information, please send us an email to: jnaude@varibox.com