| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a ball screw device, which is improved in durability life by reducing impact loads on a ball or a boundary portion between a ball rolling groove and a circulation path constituting a rolling path which is formed on the inner periphery of a nut. <P>SOLUTION: The ball screw device 1 includes: a screw shaft 2 having a spiral first ball rolling groove 5 formed on the outer periphery; the nut 3 fitted onto the screw shaft 2 and having a second ball rolling groove 6 formed on the inner periphery to face the first ball rolling groove 5; a plurality of balls 4 filled in the rolling path 7 formed by the first ball rolling groove 5 and the second ball rolling groove 6 so as to be rollable; and the circulation path 8 formed on the inner periphery of the nut 3 to return the balls 4 to the rolling path 7 in front thereof. The boundary portion 9 between the second ball rolling groove 6 and the circulation path 8 constituting the rolling path 7 is subjected to crowing 10. <P>COPYRIGHT: (C)2012,JPO&INPIT |
