Patent ID: 8683884

Claim:
A motion conversion device comprising: a base member; a rotary structural member that is held on the base member so as to rotate; a plurality of guide holding members that are provided on the rotary structural member and are held thereon so as to reciprocally move substantially in parallel with a rotary axis of the rotary structural member; a plurality of guide members that are provided respectively to the guide holding members at intervals in shifting directions of the guide holding members; a linear motion member that is held on the base member so as to reciprocally move in directions substantially in parallel with the shifting directions of the guide holding members; a rocking member that is provided to an end of the linear motion member and is held thereon so as to rock around an axis substantially perpendicular to the shifting directions of the linear motion member, while being placed so as to be in contact with parts of the guide members; three displacement generation mechanisms that are coupled to the guide holding members so as to allow parts of the guide holding members to be displaced relatively to the rotary structural member; and a control device that controls motions of the three displacement generation mechanisms so as to change a transmission gear ratio between a displacement velocity of the linear motion member and a rotation velocity of the rotary structural member.