| 摘要 |
PROBLEM TO BE SOLVED: To provide an internal-combustion-engine valve timing control device capable of achieving weight reduction while keeping a weight balance of the entire device.SOLUTION: An internal-combustion-engine valve timing control device includes: a front plate 12 that includes a plate section 13 and a cylindrical section 14 protruding forward of a front end surface 13f of the plate section 13; a vane rotor that includes a rotor 17 and four vanes provided integrally on an outer circumference of the rotor 17; and a torsion spring 32 that includes a first engagement end portion 32a engaged with a first engagement groove 17c of the rotor 17, and a second engagement end portion 32b engaged with a second engagement groove 14d of the cylindrical section 14. A concave groove 15 extending from an inner circumference to an outer circumference of the cylindrical section 14 is formed in the front end surface of the plate section 13, the concave groove 15 is formed at the same position as that of the second engagement groove 14d, and the concave groove 15 and the second engagement groove 14d are arranged at a position corresponding to a relative rotation range of the heaviest first vane. |
