A device for varying the valve control times of an internal combustion engine, especially a camshaft adjusting device with a pivotal impeller wheel, having the following features:
- 1.1 the device (1) comprises a drive wheel (2) configured as an outer rotor and drive-connected to a crankshaft of the internal combustion engine, which drive wheel (2) comprises a cavity (6) formed by a hollow cylindrical peripheral wall (3) and two lateral walls (4, 5),
- 1.2 within the cavity (6) of the drive wheel (2) at least one hydraulic working space (8) is formed by two delimitation walls (7) starting from the inside of the peripheral wall (3) and oriented toward the longitudinal central axis of the drive wheel (2),
- 1.3 the device (1) further comprises a pivotal impeller wheel (10) configured as an inner rotor and connected in a rotationally fixed manner to a camshaft (9) of the internal combustion engine and inset into the cavity (6) of the drive wheel (2),
- 1.4 the pivotal impeller wheel (10) has on the periphery of its wheel hub (11) at least one radially disposed blade (12), which extends into a working space (8) of the drive wheel (2) and divides the latter into pairs of hydraulic pressure chambers (13, 14) working in opposition to one another,
- 1.5 the pressure chambers (13, 14) are sealed off from one another by sealing elements (17) disposed at least between the free end surface (15) of each blade (12) of the pivotal impeller wheel (10) and the peripheral wall (3) of the drive wheel (2),
- 1.6 the sealing elements (17) are preferably configured as sealing strips disposed in each case within an axial groove (22) in the free end surface (15) of each blade (12) of the pivotal impeller wheel (10) and radially movable via supporting springs (23),
- 1.7 the pressure chambers (13, 14), when selectively or simultaneously subjected to the action of pressure by means of a hydraulic pressure medium, effect a pivot movement or fixing of the pivotal impeller wheel (10) relative to the drive wheel (2) and hence of the camshaft (9) relative to the crankshaft,
- 1.8 when the internal combustion engine is switched off, the pivotal impeller wheel (10) can be mechanically coupled to the drive wheel (2), with a change of volume of the pressure chambers (13, 14) of each hydraulic working space (8), in a preferred basic position for the starting of the internal combustion engine,
- 1.9 the mechanical coupling is effected by a locking element (18) disposed on the pivotal impeller wheel (10) or on the drive wheel (2) and movable by a spring element (19) into a coupling position within a complementary seating (20) in the drive wheel (2) or in the pivotal impeller wheel (10),
- 1.10 the complementary seating (20) of the locking element (18) is hydraulically connected to the pressure medium feed (21) to at least one pressure chamber (13 or 14) of a hydraulic working space (8) of the device (1),
- 1.11 when the internal combustion engine is started, as a result of the subjection to the action of pressure of a pressure chamber (13 or 14) of each hydraulic working space (8) the seating (20) of the locking element (18) is simultaneously subjected to the action of pressure and moves the latter hydraulically into an uncoupling position,
- 1.12 at least one of the sealing elements (17) between the free end surface (15) of each blade (12) of the pivotal impeller wheel (10) and the peripheral wall (3) of the drive wheel (2) of the device (1) is simultaneously configured as a locking element (18) for the mechanical coupling of the pivotal impeller wheel (10) to the drive wheel (2) of the device (1),
- 1.13 the sealing strip simultaneously configured as a locking element (18) in the coupling position is in positive engagement, by its sealing surface (27) oriented toward the peripheral wall (3) of the drive wheel (2) in one or more locking position(s) of the device (1), with, in each case, one axial fixing groove (26) configured as a complementary seating (20) in the inside of the lateral wall (3) of the drive wheel (2).