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| == Cone CVTs ==
| | #REDIRECT [[Continuously Variable Transmission]] |
| Belong to this category all the '''CVTs (Continuously Variable Transmission)'''that are constituted by one or more conical bodies that cooperate along their respective generatrices, thus realizing the variation.
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| In the one-cone type there is a revolving body (a wheel) that, moving on the generatrix of the cone, creates the variation between the inferior and the superior diameter of the cone.
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| In the CVTs constituted by two or more cones (see [http://www.gif-mbh.de/en/developments/krg/ GIF website]), these are placed in opposition (with the inferior diameter of one cone facing the superior diameter of the other cone) and the contact between all the possible diameters of the two cones is realized by a ring interposed between the cones. The variation is realized by moving the ring along the generatrix of the two cones.
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| In a CVT with oscillating cones, the torque is transmitted via friction from a variable number of cones ( according to the torque to be transmitted )to a central barrel-shaped hub. The side surface of the hub is convexe according to a determinate radius of curvature, which is smaller than the concavity radius of the cones. In this way, there will be only one ( theoretical ) contact point between the cone and the hub.
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| A new revolutionary CVT using this technology was presented in Berlin during the 6th International CTI Symposium of Innovative Automotive Transmission, on 3-7 December 2007. Its name is '''Warko'''.
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| A particular characteristic of Warko is the '''absence of clutch''': the engine is always connected to the wheels and the rear drive is realized by means of an [http://eahart.com/prius/psd/ epicyclic system] in output. This system, named “[http://john1701a.com/prius/prius-psd.htm power split]”, allows the condition of [http://www.torotrak.com/IVT/works/epicyclic.htm geared neutral] or '''"zero Dynamic"''': when the engine turns( connected to the sun gear of the epicyclic system), the variator ( which rotates the ring of the epicyclic system in the opposite sense to the sun gear), in a particular position of its range, will compensate for the engine rotation, having zero turns in output ( planetary = the output of the system ). As a consequence, the satellite gears roll within an internal ring gear.
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| '''Modularity''', '''wide ratio range (= 9)''', '''high efficiency (95%)''', '''high torque capability (up to 500 Nm)''' and '''compactness''' '''(less than 36 cm length for 31 cm diameter and 60 kg)''' are the most important characteristics of Warko.
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| The same device, with the same identical cone, in different assembly levels, covers the '''90%''' of the engines produced all over the world, with a power range that goes from 60 to 200 Hp gasoline and diesel. As a consequence, being manufactured in millions of pieces, its production costs will be comparable to mechanical transmission costs.
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| Diagrams:
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| *[http://www.warko.it/index.php?option=com_content&task=view&id=5&Itemid=8 Warko CVT]
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