IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
UP-0991882
(2004-11-18)
|
등록번호 |
US-7520192
(2009-07-01)
|
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
2 인용 특허 :
9 |
초록
▼
Methods and apparatus are disclosed for providing reduced friction in drive screw assemblies, including electromechanical actuator (EMA) assemblies. A drive screw assembly is disclosed that includes a drive shaft, a drive screw, and a screw head. A stationary guide collar having a guide bore and a s
Methods and apparatus are disclosed for providing reduced friction in drive screw assemblies, including electromechanical actuator (EMA) assemblies. A drive screw assembly is disclosed that includes a drive shaft, a drive screw, and a screw head. A stationary guide collar having a guide bore and a support surface receives the screw head or a portion of the drive screw. The guide collar may be fixed in angular relation to the screw head. As the screw head moves on a linear path during rotation of an associated drive shaft, a supported surface slides in only linear motion with respect to the support surface of the guide collar and as a result friction forces due only to linear motion are generated. Rotational friction forces and associated efficiency and power losses are consequently reduced or eliminated in the drive screw assembly. The supported surface may include a perimeter of the screw head, a circumferential surface of the second portion of the drive screw, or a circumferential surface of an intermediary screw shank.
대표청구항
▼
What is claimed is: 1. A drive screw assembly comprising: a drive shaft having a drive shaft bore defined by an inner surface having a threaded portion, said drive shaft being disposed within a housing having an outer opening connected to said drive shaft bore, said drive shaft having a longitudina
What is claimed is: 1. A drive screw assembly comprising: a drive shaft having a drive shaft bore defined by an inner surface having a threaded portion, said drive shaft being disposed within a housing having an outer opening connected to said drive shaft bore, said drive shaft having a longitudinal axis, said drive shaft being free to rotate; a drive screw disposed within said drive shaft bore, said drive screw having a threaded portion, wherein said threaded portion of said drive shaft and said threaded portion of said drive screw are configured to receive one another in a threaded connection and to rotate with respect to one another about said longitudinal axis; a guide collar fixed relative to said housing, said guide collar having a guide bore with an inner support surface, wherein said inner support surface has an inner support surface length, wherein said inner support surface is connected to an outer surface of said guide collar by an inner guide bore opening and an outer guide bore opening; and a screw head affixed to said threaded portion of said drive screw, wherein said screw head is fixed in angular relation to said guide collar, and moveable along a range from a first position to a second position on a range axis that is parallel to said longitudinal axis of said drive screw; wherein said inner support surface of said guide collar supports a supported surface of said screw head or said drive screw in directions normal to said range axis as said screw head moves through said range, wherein said supported surface slides in linear motion relative to said guide collar without substantial rotational motion and without producing substantial frictional losses due to rotational motion as said screw head moves through said range, and wherein said guide collar includes an extension sleeve that is disposed within a portion of said drive shaft bore. 2. The drive screw assembly of claim 1, further comprising one or more bearings disposed within said housing and connected to said drive shaft, wherein said one or more bearings support said drive shaft for rotational motion. 3. The drive screw assembly of claim 2, wherein said drive shaft has first and second ends, and wherein said one or more bearings comprise first and second bearings disposed at first and second ends of said drive shaft. 4. The drive screw assembly of claim 1, wherein said threaded portion of said drive shaft comprises female threads and said threaded portion of said drive screw comprises male threads corresponding to said female threads. 5. The drive screw assembly of claim 1, wherein said threaded portion has an effective diameter that is less than a diameter of a non-threaded portion of said inner surface. 6. The drive screw assembly of claim 1, wherein said guide collar is rigidly connected to said first housing. 7. The drive screw assembly of claim 1, further comprising a machine element connected to said screw head. 8. The drive screw assembly of claim 7, wherein said machine element comprises a drag link pivotally connected to said screw head. 9. The drive screw assembly of claim 1, wherein said inner guide bore opening and said outer guide bore opening are concentric with said housing outer opening. 10. The drive screw assembly of claim 1, wherein said supported surface comprises said screw head perimeter. 11. The drive screw assembly of claim 1, wherein said supported surface comprises a circumferential surface of a screw shank. 12. The drive screw assembly of claim 1, wherein said guide collar includes a round cross section along said guide bore. 13. The drive screw assembly of claim 1, wherein said guide collar includes a square cross section along said guide bore. 14. The drive screw assembly of claim 1, wherein the range from the first position to the second position is disposed within the portion of said drive shaft bore, wherein the screw head, while moving along the range from the first position to the second position, is disposed within the guide bore, and wherein the guide collar is constructed and arranged to receive substantially no frictional forces due to an attempted rotation of the drive screw. 15. An electromechanical actuator (EMA) comprising: a drive shaft having a drive shaft bore defined by an inner surface having a threaded portion, said drive shaft being disposed within a housing having an outer opening connected to said drive shaft bore, said drive shaft having a longitudinal axis, said drive shaft being free to rotate; a drive screw disposed within said drive shaft bore, said drive screw having a threaded portion, wherein said threaded portion of said drive shaft and said threaded portion of said drive screw are configured to receive one another in a threaded connection and to rotate with respect to one another about said longitudinal axis; a guide collar fixed relative to said housing, said guide collar having a guide bore with an inner support surface, wherein said inner support surface length, wherein said inner support surface is connected to an outer surface of said guide collar by an inner guide bore opening and an outer guide bore opening; a screw head affixed to said threaded portion of said drive screw, wherein said screw head is fixed in angular relation to guide collar, and moveable along a range from a first position to a second position on a range axis that is parallel to said longitudinal axis of said drive screw; and an electric motor coupled to said drive shaft, wherein said electric motor is operable to rotate said drive shaft; wherein said drive screw head moves along said range in response to rotation of said drive shaft by said electric motor, and wherein said inner support surface supports a supported surface of said screw head or said drive screw in directions normal to said range axis as said screw head moves through said range, wherein said screw head slides in linear motion relative to said guide collar without substantial rotational motion and without producing substantial frictional losses due to rotational motion as said screw head moves through said range, and wherein said guide collar includes an extension sleeve that is disposed within a portion of said drive shaft bore. 16. The EMA of claim 15, further comprising one or more bearings disposed within said housing and connected to said drive shaft, wherein said one or more bearings support said drive shaft for rotational motion. 17. The EMA of claim 16, wherein said drive shaft has first and second ends, and wherein said one or more bearings comprise first and second bearings disposed at first and second ends of said drive shaft. 18. The EMA of claim 15, wherein said threaded portion of said drive shaft comprises female threads and said threaded portion of said drive screw comprises male threads corresponding to said female threads. 19. The EMA of claim 15, wherein said threaded portion has an effective diameter that is less than a diameter of a non-threaded portion of said inner surface. 20. The EMA of claim 15, wherein said guide collar is rigidly connected to said first housing. 21. The EMA of claim 15, further comprising a machine element connected to said screw head. 22. The EMA of claim 21, wherein said machine element comprises a drag link pivotally connected to said screw head. 23. The EMA of claim 15, wherein said inner guide bore opening and said outer guide bore opening are concentric with said housing outer opening. 24. The EMA of claim 15, wherein said guide collar inner support surface supports said screw head perimeter as said screw head moves along said range. 25. The EMA of claim 15, wherein said guide collar includes a round cross section along said guide bore. 26. The EMA of claim 15, wherein said guide collar includes a square cross section along said guide bore. 27. The EMA of claim 15, wherein motor is a brushless DC motor. 28. The EMA of claim 15, wherein the range from the first position to the second position is disposed within the portion of said drive shaft bore, wherein the screw head, while moving along the range from the first position to the second position, is disposed within the guide bore, and wherein the guide collar is constructed and arranged to receive substantially no frictional forces due to an attempted rotation of the drive screw.
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