Rotary hydrodynamic blood pumps have been used to treat over a thousand patients. The Jarvik 2000 has supported a patient for seven years and uses blood immersed bearings washed by high flow to avoid excessive thrombus formation. This permits the pump to be very simple and small. Nonetheless, the present Jarvik 2000 bearings and all other mechanical blood immersed bearings of the prior art have a supporting structure that predisposes to thrombus adjacent to the bearings. The present invention provides a bearing structure that eliminates this predilection site for thrombus formation, and may provide indefinite thrombus free operation. The rotor of the preferred embodiment includes a tapered hub fabricated of wear resistant material supported by three posts at each end of the rotor, upon which the rotor rotates. Blood washes the unobstructed spaces between the posts to prevent the accumulation of a torus of thrombus that could enlarge excessively.