Drive gear and lead screw configuration with integrated speed summing differential gearing

A differential gear assembly configured for speed summing of multiple gears comprising:

• a first interface;
• a second interface;
• a splined lead screw shaft;
• a first set of planetary gears configured to be driven by the first interface;
• a second set of planetary gears configured to be driven by the second interface;
• and
• a cage to house the first and second sets of planetary gears,
• wherein the splined lead screw shaft extends through a portion of the cage and is configured to rotate in conjunction with the cage in response to the first or second ring gear driving the first or second sets of planetary gears.

A differential gear assembly configured for speed summing of multiple gears comprising:

• a first ring gear;
• a second ring gear;
• a splined lead screw shaft;
• a first set of planetary gears configured to be driven by the first ring gear;
• a second set of planetary gears configured to be driven by the second ring gear;
• and
• a cage that houses the first and second sets of planetary gears,
• wherein the cage including internal threads to mate with external threads of the splined lead screw shaft, such that rotation of the cage causes the splined lead screw shaft to traverse the cage.