Variable valve timing apparatus

A variable valve timing apparatus comprising:

• a camshaft holder connected to a camshaft;
• a cam sprocket rotating the camshaft;
• a rotation shaft disposed to the camshaft holder and having a helical structure formed thereon;
• a first driven bevel gear disposed to one end of the rotation shaft;
• a second driven bevel gear disposed to the other end of the rotation shaft and closer to the camshaft than the first driven bevel gear is;
• a connecting member engaged with the helical structure, the connecting member moving along length direction of the rotation shaft by rotation of the first driven bevel gear or the second driven bevel gear so as to change a relative phase between the camshaft and the cam sprocket;
• a first driving bevel gear engaged to the first driven bevel gear;
• a second driving bevel gear engaged to the second driven bevel gear and disposed within the first driving bevel gear;
• and
• a brake which selectively brakes the first driving bevel gear for the first driven bevel gear to rotate or the second driving bevel gear for the second driven bevel gear to rotate.