Valve drive device, in particular for an internal combustion engine of a motor vehicle, and method for operating such a valve drive device

A valve drive device (10), comprising:

• a camshaft (12) which comprises a shaft element (18) and a cam piece (20) which is drivable by the shaft element (18) and which has a first cam (24) effecting a first stroke of a valve and a second cam (26) effecting a second stroke of the valve different from the first stroke and which is displaceable in an axial direction (22) of the camshaft (12) relative to the shaft element (18) between a first position, in which the valve is actuatable by the first cam (24), and a second position in which the valve is actuatable by the second cam (26);
• an electrically controllable actuator (28) via which, as a result of an electrical control of the actuator (28), the cam piece (20) is displaceable relative to the shaft element in the axial direction (22) of the camshaft (12);
• wherein the actuator (28) is configured to push the cam piece (20) alternately back and forth between the first and second positions in a case of successive electrical controls with a same polarity;
• and
• an electronic control device (30) which has exactly one output for the actuator (28) and via which the successive electrical controls of the actuator (28), which are carried out with the same polarity, take place;
• wherein the actuator (28) is configured as a linear actuator which has a coil (34) which is supplyable with electrical current and one armature (36) which, by supplying the coil with electrical current, is moveable translationally relative to the coil;
• wherein the armature (36) is coupled to a control element (40) which is moveable with the armature (36) in a translational manner relative to the coil (34);
• wherein a forced guide (42), via which rotations of the control element (40) resulting from translational movements of the control element (40) around a rotational axis (44) can be effected;
• wherein the actuator (28) has a first actuating element (46) and a second actuating element (48) which are each moveable in a translational manner along an actuating direction (50), wherein the control element (40), during its translational movements caused by the successive electrical controls and as a result of its rotations caused by the forced guide (42), alternately actuates the first and second actuating elements (46, 48), thereby alternately moving the actuating elements (46, 48) translationally along the actuating direction (50) and thereby causing the alternating back and forth movement of the cam piece (20).