A ball screw is a linear actuator that is utilized in a vast array of industrial applications, from manufacturing and machining processes, to medical and laboratory equipment. Essentially, a ball screw is an efficient and accurate form of thrust, converting rotary motion into linear motion. Like a lead screw, the nut is the component that moves on the screw, providing the linear thrust. However, the ball screw is distinguished from the lead screw through its use of ball bearings. The bearings are partially embedded in the nut, creating a bearing cage of sorts, employed to reduce friction, increase accuracy, and reduce the rate of wear and tear. The balls or roller bearings are traveling along the thread that goes around the ball screw, and can be lubricated, which enables smoother motion and increases the efficiency of the ball screw, as well as its durability.
The ball screw can be used to facilitate accurate linear motion of heavy machinery and objects. Ball screws operate more efficiently than lead screws, due to the utilization of ball bearings and the lack of sliding friction. High precision ball screws are used in precision motion control applications, and can move a much greater load due to its ball bearing design. The geometrical contact of the thread gives the ball screw a high efficiency, and they are virtually backlash free due to their contact pattern. The nut of the screw is threaded on the inside and is fitted with grooves through which the ball bearings are loaded. This provides a rolling contact between the nut and the screw threads, which translates rotary motion into linear motion. The threaded sections of a ball screw also contains a helical groove for the balls to roll in, as well as lift-off relief.
Ball screws can be manufactured with varying leads or pitches. Standard ball screws are available in single-start or multi-start helix profiles, and those with double-start ball screws provide twice the linear travel for the same rotation of the hand wheel. Another variable is the diameter of the ball screw shaft itself, which is typically determined by the required output torque. The diameter works together with the lead of the ball screw to determine the accuracy, with larger diameters giving higher torque and speed ratings. These ball screws are available in a variety of materials, including stainless steel, aluminum, and bronze.
High precision ball screws are far more accurate than standard or recirculating ball screws, enabling extremely precise motion capabilities for industrial and manufacturing applications. With a low backlash and no contaminant leakage to worry about, these ball screws are designed for reliability and longevity. They also require less maintenance than other types of ball screws, due to their self-lubricating capabilities.
Due to the exceptional torque and low backlash characteristics of precision ball screws, they are often found in robotic applications, milling machines, optical scanners, and other motion devices. They are able to maneuver light and extremely precisely weighted objects with great accuracy. Such ball screws are machined to tight tolerances, and often come pre-loaded, mounted and supported by bearings.
In a world where precision and efficiency are required, ball screws are used to facilitate accurate and reliable linear motion in industry. By utilizing ball bearings and lift relief grooves, ball screws are more energy efficient than lead screws, and enable smoother and more accurate linear motion of heavy machinery and objects. Due to their low backlash and high efficiency characteristics, high precision ball screws are becoming increasingly popular in industry and robotics. They enable precise and accurate motion capabilities for industrial and manufacturing applications, demanding both precision and reliability.
