Rotor for a positive displacement compressor

1. A rotor for a positive displacement compressor assembly having a housing defining an inlet, an outlet, and a rotor cavity in communication with the inlet and the outlet, the rotor comprising:

a rotor body having a central longitudinal axis, a first end adjacent the inlet of the housing, a second end adjacent the outlet of the housing, an axially extending hub, and a plurality of lobes extending radially outward from the hub and axially along the hub from the first end to the second end of the rotor body,

wherein the rotor body comprises a solid outer casing and a porous inner core enclosed within the solid outer casting,

wherein the porous inner core extends between the first end and the second end of the rotor body, and

wherein the rotor body has an outer radius, and wherein the outer radius of the rotor body at the first end thereof is greater than the outer radius of the rotor body at the second end thereof.

2. The rotor set forth in claim 1 wherein the porous inner core comprises a plurality of discrete porous chambers, with each of the plurality of lobes enclosing one of the discrete porous chambers.

3. The rotor set forth in claim 1 wherein the porous inner core comprises a unitary structure enclosed within the solid outer casing of the rotor body.

4. The rotor set forth in claim 1 wherein the porous inner core comprises a multidimensional stochastic or periodic support structure.

5. The rotor set forth in claim 1 wherein the porous inner core comprises a two or three-dimensional lattice support structure or truss including a plurality of repeating unit cells.

6. The rotor set forth in claim 1 wherein each of the plurality of lobes extends in a helical path along the rotor body.

7. The rotor set forth in claim 1 wherein the solid outer casing of the rotor body has a textured or patterned outer surface.

8. A positive displacement compressor assembly comprising:

a housing defining an inlet and an outlet, the housing including a pair of end walls and a pair of intersecting sidewalls having inner wall surfaces that define first and second interconnected rotor cavities;

first and second shafts extending within the rotor cavities and supported for rotation at the end walls; and

a pair of intermeshing first and second rotors respectively supported within the first and second rotor cavities by the first and second shafts,

wherein the first and second rotors respectively comprise first and second rotor bodies having respective first and second central longitudinal axes, respective first ends adjacent the inlet of the housing, and respective second ends adjacent the outlet of the housing,

wherein each of the first and second rotor bodies has a first end face, an opposite second end face, an axially extending hub coupled to one of the shafts for rotation therewith, and a plurality of lobes extending radially outward from the hub and axially along the hub from the first end face to the second end face thereof,

wherein a porous inner core is enclosed within each of the first and second rotor bodies, and

wherein the first and second rotor cavities are frustoconical in shape.

9. The compressor assembly set forth in claim 8 wherein the first and second rotor cavities are cylindrical in shape.

10. The compressor assembly set forth in claim 8 wherein each of the first and second rotor bodies has an outer radius, and wherein the outer radii of the first and second rotor bodies at the first ends thereof is greater than the outer radii of the first and second rotor bodies at the second ends thereof.

11. The compressor assembly set forth in claim 8 wherein the first and second central longitudinal axes of the first and second rotor bodies approach each other as the rotor bodies extend from the inlet to the outlet of the housing and form an acute angle therebetween.

12. The compressor assembly set forth in claim 8 wherein the first and second shafts extend outside the housing to form at least one drive shaft, and wherein the at least one drive shaft is driven by an electric motor.

13. The compressor assembly set forth in claim 8 wherein the plurality of lobes of the first and second rotor bodies have different complementary helical shapes.

14. The compressor assembly set forth in claim 8 wherein the plurality of lobes of the first rotor body are the same shape as the plurality of lobes of the second rotor body.

15. The compressor assembly set forth in claim 8 wherein the compressor assembly is a supercharger assembly for an internal combustion engine.

16. A positive displacement compressor assembly comprising:

a housing defining an inlet and an outlet, the housing including a pair of end walls and a pair of intersecting sidewalls having inner wall surfaces that define first and second interconnected rotor cavities;

first and second shafts extending within the rotor cavities and supported for rotation at the end walls; and

a pair of intermeshing first and second rotors respectively supported within the first and second rotor cavities by the first and second shafts,

wherein the first and second rotors respectively comprise first and second rotor bodies having respective first and second central longitudinal axes, respective first ends adjacent the inlet of the housing, and respective second ends adjacent the outlet of the housing,

wherein each of the first and second rotor bodies has a first end face, an opposite second end face, an axially extending hub coupled to one of the shafts for rotation therewith, and a plurality of lobes extending radially outward from the hub and axially along the hub from the first end face to the second end face thereof,

wherein a porous inner core is enclosed within each of the first and second rotor bodies, and

wherein the first and second central longitudinal axes of the first and second rotor bodies approach each other as the rotor bodies extend from the inlet to the outlet of the housing and form an acute angle therebetween.