Variable valve actuation apparatus of internal combustion engine

A variable valve actuation apparatus of an internal combustion engine configured to vary an operating characteristic of an engine valve permanently biased in a direction closing of the engine valve by a valve spring, by changing an angular position of a second member relative to a first member, comprising;

• an electric motor in which a state of rotation of the electric motor is controlled responsively to a control signal;
• an eccentric rotation member configured to rotate eccentrically with respect to a center of rotation of an output shaft of the electric motor by torque transmitted from the electric motor;
• an inner peripheral meshing member integrally connected to one of the first and second members and having an internal toothed portion formed on its inner periphery;
• a plurality of rolling elements rotatably installed on an outer peripheral surface of the eccentric rotation member and circumferentially arranged substantially at regular intervals, and configured such that a meshing point of the plurality of rolling elements with the inner peripheral meshing member circumferentially shifts by eccentric rotary motion of the eccentric rotation member;
• and
• a cage integrally connected to the other member of the first and second members and having a plurality of lugs for circumferentially partitioning the respective rolling elements, while permitting a radial displacement of each of the rolling elements,
• wherein a radial clearance C1 between an outer peripheral surface of a specified one of the rolling elements, interleaved and deeply engaged in a space defined between the outer peripheral surface of the eccentric rotation member and an inner face of the internal toothed portion of the inner peripheral meshing member, positioned in an eccentric direction of the eccentric rotation member whose geometric center is displaced from the center of rotation of the motor output shaft and the inner face of the internal toothed portion of the inner peripheral meshing member is set to a given clearance, ranging from 10 μm to 40 μm.