Backlash reduction in epicyclic gears

An epicyclic gear assembly comprising:

• a sun gear rotatable about an axis (A);
• a plurality of planetary gears arranged around and in meshing engagement with the sun gear such that rotation of the sun gear about its axis causes corresponding rotation of each of the planetary gears about their own axes;
• and
• an outer ring gear, located axially between two fixed outer rings, the outer ring gear arranged around and in meshing engagement with the plurality of planetary gears such that rotation of the planetary gears causes rotation of the outer ring gear about the axis (A) and relative to the fixed outer rings;
• and
• a backlash reduction mechanism between the planetary gears and the outer ring gear, the backlash reduction mechanism comprising:
• a planetary gear carrier comprising a plurality of carrier segments each carrying a respective one of the planetary gears, the segments together defining an annular carrier having a bore therethrough;
• a mechanical cam supported within the bore and having a cam profile interfacing with the carrier;
• and
• a spring biasing the mechanical cam relative to the carrier in the bore;
• wherein the mechanical cam has a cam angle such that the cam is held in frictional engagement with the carrier when an induced load from the planetary gears is less than the friction at the interface between the carrier and the cam, and wherein the cam moves relative to the carrier under a force of the spring when the induced load between the carrier and the cam exceeds the friction.