The cam profile
(radial distance from the shaft’s centerline in a radial
vane design) varies as a function of angular location.
End plates enclose the housing and rotor assembly. A
working volume is generated between the rotor’s face,
two adjacent vane faces, cam wall, and end plates. The
vanes are positioned, through the cam profile, so that
the leading vane (in the direction of rotation) has a
greater exposed surface area than the lagging vane.
The pressure on the exposed vane faces is transferred
to the rotor as a net force, which then results in a net
torque to the shaft.