Published September 05, 2013
A group of Dutch inventors has developed a gearbox they say could revolutionize the automotive and bike industries. Developed by Parts Services Holland and called the Controlled Rotation System (CRS), it does away with one of the main components of a gearbox--the gears themselves. However, the team says it cannot be compared with existing continuously variable transmission (CVT) designs.
A CVT works on the principle of two cone-shaped pulleys and a V-belt. As the belt is moved up or down one of the pulleys, the gear ratio changes--hence the name "continuously variable transmission". No gears are changed, no steps between ratios are required. The CRS is similar to a CVT in that it uses a belt mounted on two discs, but the operation is different. Here, a digitally-operated hydraulic pump increases or decreases the diameter of the discs, the difference between the two changing the transmission ratio.
The system was originally developed for bicycles, to eradicate the issue of chains jumping off the gear teeth during changes. The video above demonstrates the principle--a large-diameter rear sprocket (or disc, in this case) means a low ratio; the smaller the sprocket (/disc), the higher the ratio, used at higher speeds.
The team of four then developed the bicycle system into a prototype for cars. Interestingly, they say it could work best with electric vehicles, as the electric motor could run at a constant rpm with the gearing adjusted to suit. With electric cars becoming more prevalent, it could well be a system we'll see appearing in future road vehicles.
In fact, the system can be used in several applications--from cars and motorcycles to ships and windmills. With no lubricants required and no friction in the gearless design, it's more efficient and easier to maintain. In fact, the company says it needs no maintenance. It could, as the company suggests, be perfect for a "green economy".