Internal lubrication screw pump for hollow shaft

A rotary machine comprising:

• a housing having a lubricating oil disposed therein;
• a shaft rotatable about an axis relative to said housing, said shaft having a passage extending to an end portion of said shaft;
• a screw having a body arranged coaxial to said shaft and including at least one blade extending outwardly from said body;
• a shroud arranged about said screw forming gap between said at least one blade and said shroud with rotation of said shaft and screw pumping said oil to said end portion of said shaft and into said passage;
• and
• a flow straightener arranged between said screw and said passage for controlling the flow of oil into said passage preventing a vortex.

A method of lubricating and cooling a rotary machine comprising the steps of:

• a) drawing fluid from a sump;
• b) pumping the fluid toward an end portion of a hollow shaft with a screw;
• c) pressurizing a cavity surrounding the end portion using the screw;
• and
• d) pumping the fluid through the hollow shaft.

A method of lubricating and cooling a rotary machine comprising the steps of:

• a) drawing fluid from a sump;
• b) pumping the fluid toward an end portion of a hollow shaft with a screw;
• c) pressurizing a cavity surrounding the end portion using the screw;
• and
• d) pumping the fluid through the hollow shaft, wherein prior to step d) the fluid flow is straightened to prevent a vortex.