Variators on scooters and maxi scootersThe variator in the scooter is part of the continuously variable automatic drive. Together with the V-belt and the rear converter, this technology enables a simple yet comfortable way of driving.The rear converter consists of a pulley, a counterpressure spring, the clutch and the clutch bell. The variomatic itself is an old, but not antiquated development, which has proved itself especially on scooters. It consists of a fan wheel, a variator mounted on the crankshaft including the vario rolls. These are extremely important for perfect operation and an ascending disc for the V-belt. Especially for smaller vehicles with engines without high torque, the variomatic offers a cost-effective alternative to an automatic transmission with low fuel consumption.
Operating principleThe continuously variable automatic transmission is the same as the gear shift of a bicycle. If the transmission ratio is low, i. e. the chain at the front on the smallest and at the rear on the largest gear wheel, it is slower, but easier to climb a mountain, as everyone should know. A high transmission ratio, i. e. the largest front and smallest rear gear wheel, is the fastest, as more force can be applied to the rear wheel. The stepless shifting of scooters follows this principle, but without gears. The V-belt, the equivalent of the bicycle chain, connects the rear converter and the variator located on the crankshaft and runs between conical (V-shaped) pulleys.
Within the variomatic system, the so-called variator, the variomatic rolls are located in specially designed raceways. The energy generated by fuel combustion is transmitted to the crankshaft by means of angular momentum and thus also sets the variator fixed to it in a rotary motion. The resulting centrifugal force inside the variator causes the weights to rise in their raceways, thereby pressing the entire variomatics laterally against the counter-pressure plate. This force action now reduces the distance between the conical pulleys in which the V-belt moves and "forces" it to a higher path. The transmission ratio is now larger and the scooter faster. However, since the V-belt cannot expand, the rear converter must allow the V-belt to run on a smaller track. This is also done by centrifugal force and with the help of a counter-pressure spring. If the torque decreases again, the centrifugal force decreases, the weights sink and let the discs slide apart again. Since the distance between the conical disks is directly dependent on the torque of the motor, stepless switching is possible.
Vario rollsThe so-called vario weights are responsible for the optimum work of a variomatic. Even a minimal deviation, the optimal dimensions of the weights for the respective engine, can lead to the fact that the actually possible engine power cannot be reached or used. In order to understand this, the concept of the ideal rpm range of the motor must be clarified beforehand. An engine has its highest performance within a certain speed range. Before and after this point the engine output is weaker. An optimal connection for the best possible acceleration must therefore take place exactly at the level of the ideal rpm range.
If we now apply this explanation to variomatics, we can clearly see that lighter vario weights, which rise more slowly in the variator, only force the V-belt into a higher raceway far behind the achieved ideal rpm range of the engine. With this acceleration you probably won't win a single traffic light duel. Also the max speed will be far behind what’s possible. The exact opposite is true for vario weights that are too heavy. These rise faster, forcing the V-belt into a higher transmission ratio too early, without the power speed of the motor being reached. This also has a negative effect on acceleration.
For tuning fans, there is an important point to note here. A variator is not a component that increases the performance of the engine, but it is nevertheless necessary for other tuning parts (e. g. sport exhaust) to work optimal. If, for example, a new component is used which drives number of revolutions faster into higher ranges, but the variomatics "switches" at the previously used points, you may not see any of the desired changes. It could even be, that the scooter is sower or weaker than before. In principle, the following applies: Changes have been made to power or speed - adjust. This can be a bit strenuous for one or the other - but it is worth it in any case.