| 摘要 |
The viscous coupling for a cooling air fan, especially of an internal combustion engine, comprises a drive shaft rotatable about a rotation axis, on which a housing is rotatably mounted. A partition divides the housing into a reservoir for a viscous shear fluid and a working chamber. In the working chamber there is arranged a rotor non-rotatably held on the drive shaft. The rotor together with the housing or its partition defines at least one shear gap. A controllable valve device connecting the reservoir with the working chamber controls the inflow of the shear fluid from the reservoir into the working chamber, especially in dependence upon temperature. Adjoining the partition the working chamber possesses in the region of the external circumference of the rotor an annular space formed at least partly by the rotor. The partition contains at least one over-flow opening for the shear fluid, opening into the annular space. On the housing or its partition there is mounted a baffle flap mounted for pivoting about a flap axis. The baffle flap forms a pump element effective in both directions of rotation of the rotor. The arms of the baffle flap alternately baffle the shear fluid in the annular space for pumping away and alternately close the over-flow openings. The flap axis can extend either radially or parallel with the rotation axis of the rotor. The baffle flap is preferably made symmetrical in relation to a plane including the flap axis.
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