Electrostatic motor

Patent metadata

Field	Value
Publication number	US-10958191-B2
Application number	US-201916277584-A
Country	US
Kind code	B2
Filing date	Feb 15, 2019
Priority date	Feb 15, 2018
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

An electrostatic motor includes a cylindrical rotor and a stator. Electrodes are disposed on an inside cylindrical surface of the stator. Electrets and/or electrically conductive electrodes are disposed on the cylindrical rotor and a dielectric fluid fills space between the rotor and the stator to prevent discharge of the electrets. A mask is used to charge portions of an electret cylinder or other curved surface.

First claim

What is claimed is:

1. An electrostatic motor, comprising:
a rotor, rotatable about a rotation axis and defining a first cylindrical surface having a longitudinal axis coincident with the rotation axis and having a first plurality of elongated charge members disposed circumferentially on the first cylindrical surface, each first charge member extending parallel to the longitudinal axis;
a stator defining a second cylindrical surface counterfacing, and spaced apart from, the first cylindrical surface and having a second plurality of elongated charge members disposed circumferentially on the second cylindrical surface, each second charge member extending parallel to the longitudinal axis;
wherein the first plurality of charge members is configured to have alternating polarities along the circumference of the first cylindrical surface and the second plurality of charge members is configured to have alternating polarities along the circumference of the second cylindrical surface;
wherein one surface of the first and second cylindrical surfaces is an outside cylindrical surface, and the other surface of the first and second cylindrical surfaces is an inside cylindrical surface, the first and second surfaces defining a cylindrical shell therebetween; and
a dielectric filling the cylindrical shell.

2. An electrostatic motor according to claim 1 , wherein the dielectric comprises a dielectric fluid.

3. An electrostatic motor according to claim 2 , wherein the dielectric fluid is pressurized to greater than about 101 kPa absolute pressure.

4. An electrostatic motor according to claim 2 , further comprising means for pressurizing the dielectric fluid to greater than about 101 kPa absolute pressure.

5. An electrostatic motor according to claim 2 , further comprising:
a filter in fluid communication with the cylindrical shell; and
a pump configured to circulate the dielectric fluid from the cylindrical shell, through the filter and then back to the cylindrical shell.

6. An electrostatic motor according to claim 2 , wherein at least one surface of the first and second cylindrical surfaces defines a plurality of features that extend proud of the at least one surface.

7. An electrostatic motor according to claim 6 , wherein each feature of the plurality of features comprises a chevron shape.

8. An electrostatic motor according to claim 1 , wherein the dielectric comprises a partial vacuum.

9. An electrostatic motor according to claim 1 , wherein:
one plurality of charge members of the first and second pluralities of charge members comprises a plurality of electrets arranged such that adjacent electrets are of opposite charge; and
the other plurality of charge members of the first and second pluralities of charge members comprises a first plurality of electrodes.

10. An electrostatic motor according to claim 9 , wherein charges on adjacent electrets of the plurality of electrets are sufficient to exceed breakdown voltage of air over a distance equal to spacing between the adjacent electrets.

11. An electrostatic motor according to claim 9 , wherein the one plurality of charge members further comprises a second plurality of electrodes.

12. An electrostatic motor according to claim 9 , further comprising a plurality of charging electrodes, one charging electrode of the plurality of charging electrodes for each respective electret of the plurality of electrets, each charging electrode being disposed below, and in intimate contact with, the respective electret.

13. An electrostatic motor according to claim 1 , wherein:
one plurality of charge members of the first and second pluralities of charge members comprises a first plurality of electrodes; and
the other plurality of charge members of the first and second pluralities of charge members comprises a second plurality of electrodes.

14. An electrostatic motor according to claim 1 , further comprising an electronic circuit configured to energize and commutate one plurality of charge members of the first and second pluralities of charge members.

15. An electrostatic motor according to claim 1 , further comprising a hydrostatic bearing configured to support the rotor within the stator, the hydrostatic bearing defining a plurality of fluid ports extending from an outer surface of the stator to an inner surface of the stator, ones of the plurality of fluid ports extending through ones of the second plurality of charge members, one end of each fluid port of the plurality of fluid ports being in fluid communication with the cylindrical shell.

16. An electrostatic motor according to claim 2 , wherein at least one surface of the first and second cylindrical surfaces defines a plurality of features.

17. An electrostatic motor, comprising:
a rotor, rotatable about a rotation axis and defining a first cylindrical surface having a longitudinal axis coincident with the rotation axis and having a first plurality of elongated charge members disposed circumferentially on the first cylindrical surface, each first charge member extending parallel to the longitudinal axis;
a stator defining a second cylindrical surface counterfacing, and spaced apart from, the first cylindrical surface and having a second plurality of elongated charge members disposed circumferentially on the second cylindrical surface, each second charge member extending parallel to the longitudinal axis;
wherein at least one of the first and second pluralities of charge members comprises a plurality of electrets;
wherein one surface of the first and second cylindrical surfaces is an outside cylindrical surface, and the other surface of the first and second cylindrical surfaces is an inside cylindrical surface, the first and second surfaces defining a cylindrical shell therebetween; and
a dielectric filling the cylindrical shell.

18. An electrostatic motor, comprising:
a rotor, rotatable about a rotation axis and defining a plurality of first cylindrical surfaces, each first cylindrical surface having a respective longitudinal axis coincident with the rotation axis, each first cylindrical surface having a first plurality of elongated charge members disposed circumferentially thereon, each charge member of the first plurality of elongated charge members extending parallel to the longitudinal axis;
a stator defining a plurality of second cylindrical surfaces, each second cylindrical surface counterfacing, and spaced apart from, a corresponding one of the first cylindrical surfaces, each second cylindrical surface having a second plurality of elongated charge members disposed circumferentially thereon, each charge member of the second plurality of elongated charge members extending parallel to the longitudinal axis;
wherein one surface of each of the pluralities of the first and corresponding second cylindrical surfaces is an outside cylindrical surface, and the other surface of each of the pluralities of the first and corresponding second cylindrical surfaces is an inside cylindrical surface, each first surface and corresponding second surface defining a cylindrical shell therebetween; and
a dielectric filling each cylindrical shell.

19. An electrostatic motor according to claim 18 , wherein the dielectric comprises a dielectric fluid.

20. An electrostatic motor according to claim 19 , wherein the dielectric fluid is pressurized to greater than about 101 kPa absolute pressure.

21. An electrostatic motor according to claim 19 , further comprising means for pressurizing the dielectric fluid to greater tha

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Kratchman Louis Beryl
• Bickford James A

Classifications

• H02N1/004 Primary

  in which a body is moved along a path due to interaction with an electric field travelling along the path · CPC title

• H02N2/10

  producing rotary motion, e.g. rotary motors · CPC title

• H01G7/02

  Electrets, i.e. having a permanently-polarised dielectric · CPC title