Lens barrel, imaging device, and driving device

A lens barrel comprising:

• a lens holding frame that holds a lens;
• a drive source;
• a lead screw that has a thread groove formed thereon and is rotationally driven by the drive source;
• a rotation member that has a groove that is in contact with the thread groove;
• a movement portion that is connected to the lens holding frame, rotatably holds the rotation member, and moves in an axial direction of the lead screw as the lead screw rotates;
• and
• a biasing portion that biases the rotation member toward the lead screw in a direction orthogonal to the axial direction of the lead screw.

A driving device comprising:

• a drive source;
• a lead screw that has a thread groove formed thereon and is rotationally driven by the drive source;
• a ring-shaped member that has a groove on an inner periphery thereof, the groove being in contact with the thread groove;
• a holding member that rotatably holds the ring-shaped member;
• a biasing portion that biases the ring-shaped member toward the lead screw in a direction orthogonal to an axis of the lead screw,
• wherein the ring-shaped member moves in an axial direction of the lead screw together with the holding member while rotating in accordance with rotation of the lead screw.