Compliant gear assembly, engine and gear train operating method

An internal combustion engine comprising:

• an engine housing;
• a gear train mounted to the engine housing and including a crank gear, a cam gear and an idler gear coupled between the crank gear and the cam gear and configured to transmit a torque between the crank gear and the cam gear;
• the idler gear including a first hub component mounting the idler gear to the engine housing and including a front face and a back face and defining a first axis which extends through the first hub component and is oriented normal to the front face, the idler gear further including a second hub component movable in a direction perpendicular to the first axis between a first stop position and a second stop position, and a gear ring defining a gear ring axis of rotation;
• and
• the gear ring being coupled to move with the second hub component between the first stop position at which the gear ring axis of rotation is co-linear with the first axis and the second stop position at which the gear ring axis of rotation is parallel to but not co-linear with the first axis, and the idler gear further including a compliance mechanism coupled between the first hub component and the second hub component and biasing the second hub component toward the first stop position.

A method of operating a gear train of an internal combustion engine comprising the steps of:

• biasing a gear ring of an idler gear of the gear train toward a first stop position at which an axis of rotation of the gear ring, an axis of rotation of an input gear meshing with the gear ring and an axis of rotation of an output gear meshing with the idler gear define a first pattern;
• transferring a first torque between the input gear and the output gear by way of the idler gear with the gear ring at the first stop position;
• limiting transferring a second torque greater than the first torque between the input gear and the output gear at least in part by moving the gear ring responsive to application of the second torque thereon toward a second stop position at which the axis of rotation of the gear ring, the axis of rotation of the input gear and the axis of rotation of the output gear define a second pattern different from the first pattern;
• and
• returning the gear ring to the first stop position.