US Patent 7597075 Electrically driven camshaft adjuster

Adjustment device (1) for adjusting a relative rotational angle position of a camshaft (3) relative to a crankshaft of an internal combustion engine is provided. The adjusting device includes a crankshaft-fixed drive part (4) and a camshaft-fixed driven part (5). The adjustment device (1) has an adjustment motor (2) as a primary adjustment device and an auxiliary drive (11) as a secondary adjustment device. When the adjusting motor fails, the camshaft (3) can be moved into a fixed rotational angle position, an emergency running position, by the auxiliary drive (11).