| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable valve device capable of accurately controlling the position of a valving element.SOLUTION: A variable valve device 20 includes an electric motor 30, a ball screw mechanism 40, a first coil spring 70, a second coil spring 80, a valving element 60, and a control part. The ball screw mechanism 40 includes a screw shaft 41, a ball nut 42 into which the screw shaft 41 is inserted, and a plurality of balls. The valving element 60 reciprocates in association with the reciprocation of the ball nut 42. The electric motor 30 rotates the screw shaft 41. The first coil spring 70 energizes the ball nut toward the valving element 60. The second coil spring 80 energizes the ball nut 42 toward the electric motor 30. The control part controls the drive of the electric motor 30 on the basis of the rotating angle of the electric motor 30. The control part calculates the position of the valving element 60 while taking into consideration of a force working on the ball nut 42 caused by a torsional stiffness of the first coil spring 70 and a torsional stiffness of the second coil spring 80, as a correction amount. |
