Patent attributes
A reciprocating drive mechanism for converting motor rotation into linear motions to produce a reciprocating drive force, and a press machine using the mechanism. The rotation of a first motor (20A) out of two motors (20A) and (20B) is converted into a high-speed low-torque rotational output and transmitted to a ball screw mechanism (50) by a first power transmission mechanism (30). The rotation of the second motor (20B) is converted into a low-speed high-torque rotational output and transmitted to the ball screw mechanism (50) by a second power transmission mechanism (40). The ball screw mechanism (50) is made of a feed screw (52) supported in a screw hole of a nut member (51) so as to be capable of screw-fed rotation. The feed screw (52) and the nut member (51) are coupled with the first power transmission mechanism (30) and the second power transmission mechanism (40), respectively. A corotation prevention mechanism (80) prevents the feed screw (52) from rotating together with the rotation of the nut member (51).
