A ball screw is an essential component in many different types of equipment from robotics to automobiles and from automated equipment through to aerospace applications. It is a simple device, but it is critical to be able to convert rotational to linear motion or vice versa.
The way this works is through the use the ball screw and the ball nut. Both must be precisely crafted and also selected for the specific application as incorrect matching of the screw to the application can result in limited life cycles, extensive downtime, and significant costs.
The Assembly
The ball screw assembly includes the ball nut and the ball screw. These are precisely crafted and machined to have identical grooves that are helical in space. Within these grooves, small balls roll to actually support the nut without the nut actually making any direct contact with the screw grooves or ridges.
To allow the nut to move down the length of the screw, there is a ball return system in the nut. This allows a continuous flow of the ball that matches the speed at which the nut is traveling down or up the length of the screw. In this way, they continue to recycle and recirculate in the closed system within the nut.
Return Systems
A ball nut can be designed with either an internal or an external ball return system. The external has the balls circulate through small tubes that are on the exterior of the nut. These tubes do not extend beyond the widest part of the nut, which protects the tubes.
The internal type of return has the tubes under the outside of the body of the nut. The design is similar, but the location of the tubes will be different. Both options can be a good choice for most applications.
