Rotary drive apparatus

A rotary drive apparatus that rotates a flywheel holding a mirror that reflects incoming light coming from a light source, and a lens that allows reflected light obtained by reflection of the incoming light to pass therethrough, the rotary drive apparatus comprising:

• a motor;
• and
• the flywheel;
• wherein
• the flywheel is supported by the motor and is rotatable about a central axis extending in a vertical direction;
• the lens includes:
• a base portion including a light-transmitting portion that allows the reflected light to pass therethrough;
• and
• a projecting portion that projects in an axial direction relative to the base portion;
• the flywheel includes an accommodating portion in which the lens is located;
• the accommodating portion includes:
• an insertion opening at an upper portion of the accommodating portion to allow the lens to be inserted therethrough;
• a support surface below a light path of the reflected light to support the lens;
• a slanting surface located radially inside of the lens and opposite to a radially inner surface of the lens, at a position at at least below the light path of the reflected light, and slanting radially outward with decreasing height;
• an outer wall portion located radially outside and opposite to the slanting surface, and extending in the axial direction;
• and
• a window portion located to pass through the outer wall portion in a radial direction, and to allow a portion of the base portion of the lens to be inserted therein;
• the insertion opening extends from the slanting surface to an inner surface of the outer wall portion in the radial direction;
• a shortest distance, measured along a normal to the slanting surface, between the slanting surface and a portion of the inner surface of the outer wall portion above the window portion is greater than a thickness of the base portion of the lens measured in the radial direction;
• a dimension of the window portion measured in the vertical direction is greater than a dimension of a portion of the base portion inserted in the window portion measured in the vertical direction;
• and
• the dimension of the window portion measured in the vertical direction is smaller than a dimension of the projecting portion of the lens measured in the vertical direction.