Variable valve timing device and assembly method of variable valve timing device

1. A variable valve timing device comprising:

a case for rotating integrally with a crankshaft of an engine;

a rotor housed in the case, to be rotated integrally with a camshaft of the engine by fastening the rotor coaxially to the camshaft with a center bolt; and

at least one torque receiving part provided around an axis of the rotor on an opposite side of the rotor to the camshaft, and having a flat surface intersecting a rotation direction of the rotor, wherein

the at least one torque receiving part is a groove whose side wall includes the flat surface,

the rotor has a recess in a center of a hub,

the groove is provided on a bottom surface of the recess,

the groove has an inner wall on a radially inner side of the groove and an inner wall on a radially outer side of the groove, and the inner walls face each other across the groove and intersect the side wall, and

the inner wall on the radially outer side is continuous with and flush with an inner wall of the recess.

2. The variable valve timing device according to claim 1 , wherein the at least one torque receiving part includes a plurality of torque receiving parts, and

the plurality of torque receiving parts are equiangularly spaced around the axis of the rotor.

3. The variable valve timing device according to claim 1 , wherein the groove penetrates the rotor in an axial direction of the rotor.

4. An assembly method of a variable valve timing device comprising:

attaching a jig to the at least one torque receiving part of the variable valve timing device according to claim 1 ; and

fastening the rotor to the camshaft with the center bolt in a state in which the flat surface of the at least one torque receiving part and a part of the jig are in surface contact with each other in the rotation direction of the rotor.