| 摘要 |
A ball screw comprising a threaded rod and a ball nut making a rectilinear motion around the rod as the rod is rotated. A first load ball groove and a second load groove which have an offset relation to each other are formed in the inner surface of the ball nut. A pre-load is imparted to ball bearings rolling in these two load grooves. The ball nut has a resilient portion between the first and second load ball grooves. The resilient portion can be displaced axially. Any excessive pre-load created by the error introduced either in the lead of the ball-rolling groove or in the lead of the first or second load ball groove is absorbed by the resilient portion. Consequently, the novel ball screw is superior in accuracy to the prior art ball screw, and is easier to fabricate. |
