ACTUATOR OF VARIABLE VALVE GEAR AND LIFT CHARACTERISTIC DETECTION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an actuator of a variable valve gear in which an actuation position of a control shaft can be inexpensively detected.

SOLUTION: The actuator of a variable valve gear includes: a ball screw shaft 45 along which a rotative force of an electric motor 36 is transmitted; a ball nut 46 which is moved in the axial direction of the ball screw shaft in accordance with the rotation of the ball screw shaft; a link 48 which converts a reciprocating movement of the ball nut into the rotating movement and transmits the rotating movement to the control shaft; and a coil spring 59 which is elastically disposed between a first spring retainer 56 on the ball nut side and a second spring retainer 57 on the housing edge wall 35c side and biases the ball nut to the electric motor side in the axial direction. The actuator of a variable valve gear further includes a lift characteristic detection device 80 which has a strain sensor 80a for detecting a strain change due to spring displacement of the coil spring and which is disposed on an external surface 35h of the edge wall. The actuator uses the value of the strain change to calculate a movement position of the ball nut and converts the present rotation angular position of the control shaft.

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