#video of supposedly “first” geared #CVT #mechanisms. Very complex and confusing. The design is "RatioZero" by Edyson Pavilcu, who is looking for investors. Uses variable lever arms implemented via slots in rotating gears. And apparently a one-way freewheel or ratchet mechanism on other gears (the current design uses a literal clicky ratchet and pawl). But ratchet-based CVTs have been known for a century. This one uses elliptical gears to reduce (but not eliminate) the torque ripple that plagues ratchet-based CVTs.
on 02024-12-01a #cvt (continuously variable transmission) using cones and a ring with very low power control: “By moving the ring, and with that the two contact points, parallel to the cone surface the running radius of both the ingoing and the outgoing cone changes. This means a change in the transmission ratio. The ring is moved by giving it a small steering angle, similar to steering a bicycle wheel. By adjusting this steering angle, the position of the ring and as a consequence the transmission ratio, can be controlled. The steering is done by a small electric motor. The advantage of this system is that little power is needed for the ratio adjustment (less than 20 W). A disadvantage is that similar with a bicycle, the steering angle has to be adjusted continuously to keep the system stable.” This is exactly what I was hoping you could do with a cone ring transmission to build an infinitely variable transmission for robotics. By the GIF, “Gesellschaft für Industrieforschung mbH”. #pdf
on 02015-11-0210MB catalog of Đức thắng Nguyễn’s #mechanical mechanism #video illustrations, in three PDF files, organized by topic. Including, say, a dozen or so designs for continuously variable transmissions (#cvt), a bunch of negative #stiffness mechanisms, and so on. Entirely rigid bodies as far as I can tell except for the occasional coil or leaf spring.
on 02015-08-15