Which component in a servo traverse axis converts motor rotation to linear motion?

The ball screw drive is the correct option because it effectively converts the rotational motion of a motor into linear motion. This is achieved through a screw mechanism in which a rotating screw causes a nut, typically equipped with ball bearings, to move linearly along the screw's length. This system allows for precise control of the position and movement, making it ideal for applications that require accuracy, such as in CNC machines or robotic systems.

Other components like belt drives and chain drives transfer rotational motion but do so in a way that does not inherently convert it to linear motion. For instance, a belt drive allows for the transmission of motion over a distance but relies on additional mechanical configurations to achieve linear motion. Similarly, a chain drive functions in the same manner as a belt drive, transferring power without directly facilitating a linear transformation. Linear actuators, on the other hand, could perform the conversion, but they are distinct devices designed for linear movement without combining elements of screw-based motion. Hence, the ball screw drive stands out as the most effective solution for this specific conversion task.