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Ball Screw Structure And Innovation
1, Appropriate increase of the ball screw lead Pn and the number of the screw thread head is the best choice for the realization of high speed

In the early 1989 we completed a large lead ball screw "the Seventh Five Year Plan" research, helix angle of φ> 9°~ 17° large lead ball screw has achieved mass production. However, due to genetic of thread grinder Transmission Chain Error "gene", the greater the lead, lead accuracy is difficult to improve.

2, Improvements to the ball

In high-speed motion, the ball spin rate, revolution speed, centrifugal force are large, ball hit each other, in and out of the reversing mechanism of the instant impact is very big also. There are four methods to solve this problem: through optimization calculation on ball chain, appropriate to reduce the size of the balls; use hollow ball, use hollow ball screw assembly can effectively reduce the moment of inertia, increasing screw speed; change the balls arrangement, arranging the balls in the ball chain according to a large and a small interval; use silicon nitride ceramic balls.

3, Adding a ball retainer

After adding the ball retainer in the screw, avoid direct friction between the balls body to achieve a quiet, smooth running, long lubrication cycle, high-speed, durability and other effects.

4, Hollow strong cold

At high speeds, thermal deformation of the screw shaft is a source of processing error, in order to improve system rigidity, the screw shaft pre-stretching will generate heat. Effective way to solve the heat problem is the coolant through the hollow screw internal forced circulation cooling, which also helps to reduce the inertia of the high-speed operation, and increase torsional rigidity of the screw shaft.

5, Improved ball nut structure

(1) Ways to improve preload, the dynamic control of the preload Fp. In the high-speed operation, in order to maintain the ball screw rigidity and precision does not change in the entire stroke range, must make the Fp is not lost, dynamic preload torque Tp constant.

(2) When the ball in and out of the reverse mechanism, will repeat produce Brinell Effect, namely the Brinell impact wear. Therefore, should according to the requirements of the high speed of reverse circulation mechanism of optimization design: the inner loop reverse structure and return bead groove curve parameters optimization, use high oil, high-density fiber antifriction materials make the balls in the cycle "soft landing", outer loop guide beads tube made of high strength thick quality alloy material, increase the radius of curvature, the pipe wall and tongue implementation of the enhanced processing, the reverser and the guide beads tube on the coordinate position of the ball nut body optimized layout.

(3) Other vibration reduction noise reduction measures include: the ball nut body surrounding configuration for preventing noise casing, etc..

6, Ball Screw under implementation of dual-motor drive

Use a servo motor to drive the ball screw shaft, another servo motor to drive the ball nut supported by bearings in the opposite direction, so that the feed rate of the working table can be almost doubled.

7, Change the drive mode

When the screw stroke is long, the "Screw rotation → nut movement" screw drive mode can be changed to "Screw fixed, Nut rotation while moving" nut drive mode.

8, Improved ball screw frictional properties

In the thread roller, ball return path, the ball surface with a coating allows the frictional torque at high speed can be reduced by about 10%, significantly reducing the ball in a non-pure rolling "slippage" in the process of thread rolling abrasions and prolong life.