Hydraulic motor from the group known as annular gear motors which operate in accordance with the planetary principle. The distinguishing feature of planetary motors is how lots of displacement chambers are created with each revolution, which results in very high displacement and therefore very high torque. An underlying rotatory movement is also generated, which makes the planetary motor suitable for use at slow speeds.
Planetary motors include the orbit motor and the MZK motor (Figure P 10).
Figure P 10: Planetary motor of the MZK type