Rotational driving apparatus for testing internal combustion engine

A rotational driving apparatus for testing an internal combustion engine to which a ring gear is attached, comprising:

• a rotation shaft that is coaxial with a rotation axis of the ring gear;
• a rotor that can rotate as a single unit with the rotation shaft and that has a portion extending in a radial direction with respect to the rotation shaft;
• a pivot portion supported by the rotor at a support position that is substantially away from the pivot portion's front end and rear end in the axial direction of the rotation shaft, the pivot portion having an engaging portion in a region of its front end that is engageable with the ring gear, wherein, when the rotor is rotated, a torque in a direction in which the engaging portion is caused to engage the ring gear is generated by a portion of the pivot portion between the support position and the rear end;
• a pivot shaft that is provided either on the rotor or the pivot portion and that has an axis in a direction perpendicular to the direction of the axis of the rotation shaft, the pivot portion being pivotable about the pivot shaft;
• a reciprocating member that can be shifted back and forth in the direction of the axis of the rotation shaft;
• a link that is pivotably linked to either the rotor or the pivot portion and that is pivotably linked to the reciprocating member;
• and
• an actuator for shifting the reciprocating member along the direction of the axis of the rotation shaft.