CVT- Continuously Variable Transmission

tilting a planet gear relatively to the ring plane

Consider a ring gear and a planet gear. The planet rotates along the ring gear. The planet's diameter is half of the ring's diameter.

In this special arrangement the ring gear has teeth in both sites and also along the edge. So, the planet gear can be tilted out of the ring plane. Therefore, the planet can rotate inside the ring, along the lateral edge or outside the ring. Moreover, the planet gear can be tilted in any angle, relatively to the ring gear plane.

1.a) Planet gear rotating inside the ring gear:
When the planet completes one turn arround the ring it completes 1 turn arround it's own axis.		 1.b) Planet gear rotating along the side edge of the ring gear:
When the planet completes one turn arround the ring it completes 2 turns arround it's own axis.		 1.c) Planet gear rotating outside the ring gear:
When the planet completes one turn arround the ring it completes 3 turns arround it's own axis.
interior: 1 turns along the edge: 2 turns exterior: 3 turns


These animations evidence that the planet gear will have different rotations arround it's own axis: 1, 2 or 3. These values are obtained when the tilt angle between the planet and the ring is 0 degrees (inside), 90 degrees (along the edge) and 180 degrees (outside).

This could motivate someone to induce that the angular velocity of the planet gear varies continuously with the tilt angle. Therefore, a fully geared CVT (continuously variable transmission) could be built. Unfortunately this is not yet the "Holy Grail" of Mechanical Engineering (CVT). The planet motion varies, however the mechanisms that connect to the planet will neutralize this variation.

For example, consider using constant velocity joints and telescoping shafts, connected the center of the planet gear:

For example, consider using constant velocity joints, connected the center of the planet gear.

Four or five constant velocity joints in line, one after the other would create something like a "flexible shaft". Thus, when the tilt angle is 180 degrees, the "flexible shaft" would go through the inside of the ring gear.

2.a) Planet gear rotating inside the ring gear:
The planet completes 1 turn arround it's own axis and the output shaft completes 1 turn too.		 2.b) Planet gear rotating along the side edge of the ring gear:
The planet completes 2 turns arround it's own axis, but the output shaft completes only 1 turn.		 2.c) Planet gear rotating outside the ring gear:
The planet completes 3 turns arround it's own axis, but the output shaft completes only 1 turn.
interior: 1 turns along the edge: 2 turns exterior: 3 turns

Once again, physics has ruined our plans:
Although the planet gear will completes 1, 2 or 3 turns arround it's own axis, the output shaft will complete always 1 turn. Therefore, this device couldn't be used to vary the output speed.




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