At the heart of the Rineer Hydraulics, Inc.® motor is a patented vane-crossing-vane design, a unique idea in fluid power transmission. This design allows for low speed high torque and high speed high torque making it one of the most versatile motors in the industry.

The Rineer motor is a bi-rotational rotary power converter utilizing working vanes in the rotating member (rotor, see Fig. 1), and sealing vanes in the stationary member (stator). These vanes are hydraulically and spring loaded, and are radiused on their crossing edges. The rotor vanes, when acted upon by a differential pressure, exert rotational force on the rotor. As oil enters the "A" ports, the rotor vanes rotate clock-wise toward the "B" ports. As each rotor vane is finishing its work cycle in a cavity, another rotor vane starts its work cycle in that cavity.
There are four rotor vanes working at any given time. For example, as the two vanes marked "C" have just started their work cycle and are continuing to "cam out," the two vanes marked "D" are just past the mid-point of their work cycle and are "camming back". This results in approximate constant vane extension and, therefore, the output approaches constant torque regardless of radial location. Each rotor vane works once per cavity per revolution resulting in 40 power strokes in a four cavity (10 rotor vane) motor.