Fluidlexikon

Hydraulic motor

Device for converting hydraulic energy (Q, p) into mechanical energy (M, n) by creating a certain torque and rotation speed. Neither is dependent on the other: the rotation speed n 2 is only dependent on the flow rate Q 1 introduced and the displacement V 2:

while the torque M 2 is determined by the load pressure p L and the displacement V 2:

In general, all pumps (with the exception of valve-controlled pumps) can now also be used as high-speed hydraulic motors. In addition, there is also a range of special designs such as the Orbitmotor®, rolling vane motor or rigid vane motor and the like, as well as the group of slow speed high torque motors.

The critical characteristics of a hydraulic motor include:

  • The minimum rotation speed, which depends on the friction and leakage losses
  • The starting performance, the starting torque of which and a potential stick-slip-effect depend heavily on the friction
  • The uniformity of the movement, which is influenced heavily by a fluctuating torque with an uneven number of pistons.