The invention relates to a camshaft adjusting mechanism for adjusting the phase position of a camshaft relative to a camshaft drive or crankshaft of an internal combustion engine.
Variable valve timing in order to optimize the fuel consumption and engine power output in motor vehicles is already known. It is possible, for example, to adjust the phase position of a camshaft in relation to the crankshaft in order to vary the valve actuation. Such arrangements for adjusting the phase position usually take up a relatively large overall space, which is not readily available in modern vehicles accommodating numerous assemblies. In order to adjust the phase position, use may be made, for example, of a hydraulic vane adjuster, the rate and angle of adjustment of which, however, are very limited. At low engine speeds and low oil pressure, and when the vehicle is at standstill, the phase position cannot be adjusted.
These problems can be avoided by using electrically driven adjusting mechanisms. The published patent application DE 100 38 354 A1 discloses an electrically driven adjusting mechanism having an adjusting device for adjusting the phase position of the camshaft in relation to a crankshaft driven by an internal combustion engine, together with a drive gear, driven by the crankshaft, for driving the camshaft, in which a swash plate mechanism is provided. Such an arrangement, however, entails high costs because of the highly geared two-stage transmission and the servomotor which are required.
DE 41 33 408 A1 discloses a camshaft adjusting mechanism in the form of a four-shaft transmission in which two drive shafts are provided for adjustment, which can be simultaneously subjected to a brake torque.
It is the object of the present invention is to provide a very compact and inexpensive camshaft adjusting mechanism.