| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve durability of a planetary differential screw type rotation-linear motion converting mechanism. <P>SOLUTION: In the planetary differential screw type rotation-linear motion converting mechanism 2, a relation between a gear ratio A between gears 6b, 8b of a sun shaft 6 and a planetary shaft 8 and a number of threads ratio B between screws 6a, 8a is A<B, and a relation between an effective diameter Dg of the planetary gear 8b and an effective diameter Ds of the planetary screw 8a is Dg>Ds. Accordingly, the difference in a lead angle between the planetary screw 8a and the sun screw 6a which generates the differential is reduced. Thus, the extreme pressure on a contact surface between teeth planes of screw teeth between the planetary screw 8a and the sun screw 6a can be reduced, and the friction can be restrained. Therefore, the durability of the planetary differential screw type rotation-linear motion converting mechanism 2 can be improved, and further, the conversion efficiency is improved. <P>COPYRIGHT: (C)2012,JPO&INPIT |
