A radial pump has a housing with a cylinder ring is pivotally mounted
therein. The cylinder ring has a circular aperture within which a cam
surface is formed. A cylinder block rotates within the cylinder ring
aperture and has a plurality of radially extending cylinders each having
port which selectively communicates with a fluid inlet and a fluid outlet
as the cylinder block rotates. A plurality of pistons is slideably
received within the cylinders and engages the cam surface. An actuator
operably coupled to produce movement of the cylinder ring, which alters
the spatial relationship between the cylinder ring and the cylinder block
to vary the amount that the pistons move within the cylinders. The amount
of movement of the pistons within the cylinders is directly related to
the magnitude of fluid flow delivered by the pump and moving the cylinder
ring thereby controls the fluid flow.