| 摘要 |
PROBLEM TO BE SOLVED: To provide a valve timing control system of an internal combustion engine, which can combine operation responsiveness of an intake side VTC (Valve Timing Controller) with phase holding property of an exhaust side VTC.SOLUTION: An intake side VTC 04 and an exhaust side VTC 05 include electric motors 12, 72 outputting torque by being energized, speed reduction mechanisms 8 and planetary gear mechanisms 74, which reduce rotation speeds of the respective motors and change valve timing of an intake valve and an exhaust valve. The speed reduction mechanism 8 of the intake side VTC has a structure of less friction which transmits torque with tooth parts and rollers, and the speed reduction mechanism 74 of the exhaust side VTC has a structure of relatively large friction which transmits torque through meshing of tooth parts, so that both operation responsiveness of the intake side VTC and phase holding property of the exhaust side VTC can be satisfied. |
