Ball screw transmission characteristics

Transmission principle of ball screw
The principle of the transmission is driven by the servo motor, the screw to do high-speed movement, through the nut to drive the machinery fixed on the nut.

Ball screw transmission feature
Ball screw transmission mechanism between the screw and nut add the balls as intermediate element, so that the screw and nut sliding friction transmission changed into rolling friction transmission.

On the ball screw nut is formed with a spiral groove arc surface, the two arc spiral groove on the surface together to form the raceway. There are many balls in the raceway, therefore, is rolling friction between the screw and nut. In the nut 2 is equipped with blocking bead detector at both ends of the spiral groove, and the return pipeline for balls after get out of the nut body from one end of the helical groove, and back along the pipeline return to the other end of the raceway. Thus, when the ball screw relative to the nut rotation to do linear motion feed drive, the ball is in the spiral raceway circulated continuously scrolling.

Ball screw transmission advantages:

1, High transmission efficiency. Transmission efficiency of ball screw transmission is generally 90% to 98%, while the transmission efficiency of ordinary sliding screw transmission is 20% to 40%.

2, High transmission accuracy, stable movement, no crawling phenomenon. The ball screw transmission is basically rolling friction, the friction resistance is small, the friction force is almost no relationship with the speed of movement.

3, Reverse no idle stroke. The ball screw and nut can eliminate the axial clearance after being pre-tightened. In this way, there is no idle stroke when the reverse, can improve the axial transmission accuracy and axial stiffness.

4, Reversibility. Due to the small friction loss of the ball screw transmission, it can be converted from the rotating motion to linear motion, and it can be converted from the linear motion to rotating motion. Both the screw and the nut can be used as the active part, and can also be used as a follower.

5, Long service life. Because the friction loss of rolling friction is small, so the service life is longer. As the ball screw has the above advantages, as a kind of precision and energy saving transmission mechanism, the application of ball screw in precision machine tools, CNC machine tools is more common.

Ball screw transmission disadvantages:

1, High cost. Due to the higher processing precision of ball screw and nut and other components, lower roughness, so the higher manufacturing costs. Screw and nut on the spiral groove raceway to be ground forming surface, the process requirements are complex, difficult to manufacture.

2, No self-locking. In particular vertical screw, due to the inertia force of the self weight, moving parts after the transmission stopped can not be self-locking, need to add the braking device.

Ball screw adjustment
Generally not recommended by adjusting shims to adjust the preload, because the ball has been worn, it is best directly replace the ball. Specific replace how big the ball, depending on the screw specifications, of course, can be sent to a professional screw factory maintenance is the best. However, this only as a temporary emergency measure, the ultimate solution is still to buy a new screw.

Source: http://www.machineballscrew.com Ball Screw Assemblies Manufacturer.