Patent ID: 7841312

Claim:
An adjustment device for a camshaft, the adjustment device comprising a brake system and a superposition gear system which is connected on a drive output side to the camshaft and on a drive input side to a crankshaft, such that to adjust the camshaft, the superposition gear system dissipates a portion of energy from the drive input side into the brake system, the brake system being a frictional brake system in which a necessary braking force is produced by a friction lining ( 2 ) that operates permanently in a slipping condition and the brake system being an electromagnetically actuated frictional system, the brake system comprises an electrically actuated shift solenoid ( 1 ) having a friction surface ( 8 ), a friction lining ( 2 ) with a locking element ( 6 ) that co-operates with a drive-side element ( 5 ) of the superposition gear system ( 7 ), and a spring ( 3 ), the friction lining ( 2 ) being axially slidable and rotationally fixed on a spur gear ( 4 ) of the superposition gear system ( 7 ), such that when the shift solenoid ( 1 ) is not energized, the force of the spring ( 3 ) and via the friction lining ( 2 ) and the locking element ( 6 ), the spur gear ( 4 ) is positively engaged with the drive-side element ( 5 ) of the superposition gear system ( 7 ), and when the shift solenoid ( 1 ) is energized, a magnetic force on the friction lining ( 2 ), causes the spur gear ( 4 ) to contact with the friction surface ( 8 ) of the shift solenoid ( 1 ) such that a braking torque built up by the shift solenoid ( 1 ) is transmitted, via the spur gear ( 4 ), to the superposition gear system ( 7 ).