Patent ID: 8082818

Claim:
A planetary rotary/linear motion converter comprising a sun shaft, planetary shafts, and a ring shaft having respective axes of rotation in parallel with one another; a helical sun gear, helical planetary gears, and a helical ring gear respectively provided on the sun shaft, the planetary shafts, and the ring shaft and cooperatively constituting a first planetary gear mechanism; and a screw sun gear, screw planetary gears, and a screw ring gear respectively provided on the sun shaft, the planetary shafts, and the ring shaft and cooperatively constituting a second planetary gear mechanism, wherein either of a gear ratio of the screw sun gear to the screw planetary gears and a gear ratio of the screw ring gear to the screw planetary gears differs from a gear ratio of the helical sun gear to the helical planetary gears and from a gear ratio of the helical ring gear to the helical planetary gears.