Position feedback pilot valve actuator for a spool control valve
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F15B-013/043
F15B-013/00
출원번호
US-0013667
(2004-12-16)
등록번호
US-7422033
(2008-09-09)
발명자
/ 주소
Barber,Dennis R.
출원인 / 주소
HUSCO International, Inc.
대리인 / 주소
Quarles & Brady
인용정보
피인용 횟수 :
12인용 특허 :
16
초록▼
A spool type control valve is operated by an electrically driven pilot valve. A pilot piston is attached to the control spool. As an electrical actuator moves the pilot spool, a greater pressure is applied to one side of the pilot piston than the other side, which causes movement of the control spoo
A spool type control valve is operated by an electrically driven pilot valve. A pilot piston is attached to the control spool. As an electrical actuator moves the pilot spool, a greater pressure is applied to one side of the pilot piston than the other side, which causes movement of the control spool. When the control spool reaches the desired position, its positional relationship to the pilot valve defines a pressure differential across the pilot piston which exerts a net force on the control spool that counterbalances a spring force acting on the control spool. This defines an equilibrium position at which the control spool remains until subsequent motion of the pilot spool occurs which alters the pressure differential across the pilot piston.
대표청구항▼
What is claimed is: 1. In a valve assembly having body in which a control spool selectively controls flow of fluid between at least one workport and both a supply passage and a return passage, a pilot valve comprising: a piston bore formed in the body; a pilot piston connected to the control spool
What is claimed is: 1. In a valve assembly having body in which a control spool selectively controls flow of fluid between at least one workport and both a supply passage and a return passage, a pilot valve comprising: a piston bore formed in the body; a pilot piston connected to the control spool and slideably received in the piston bore, thereby defining a first chamber and a second chamber in the piston bore, wherein the pilot piston is tubular and extends around the control spool; a pilot spool slidably received in the body and moveable into first and second positions with respect to the control spool, wherein in the first position the first chamber communicates with the supply passage but not with the tank passage and the second chamber communicates with the tank passage, and in the second position the second chamber communicates with the supply passage but not with the tank passage, wherein the pilot spool is slidably received within a bore in the control spool and wherein the pilot spool has passages therein which form the fluid paths between each of the first chamber and a second chamber and the supply passage and a return passage in selected positions of the pilot spool; and a linear actuator engaging the pilot spool to move the pilot spool with respect to the control spool. 2. In a valve assembly having a control spool which selectively controls flow of fluid between at least one workport and both a supply passage and a return passage, a pilot valve comprising: a body with a bore into which the control spool extends, a first opening into the bore communicates with one of the supply passage and the return passage, and a second opening into the bore communicates with the other of the supply passage and the return passage; a pilot piston connected to the control spool and slideably received in the bore thereby defining a first chamber and a second chamber in the bore, the pilot piston having a feeder aperture that communicates with the first opening in the body and with a first aperture in the control spool; a pilot spool slidably received in a pilot bore in the control spool and having a first position which provides fluid paths between the first aperture and both the first chamber and a second chamber in the bore, a second position at which communication is provided between the first aperture and the first chamber and between the second aperture and the second chamber, and a third position at which communication is provided between the second aperture and the first chamber and between the first aperture and the second chamber; and a linear actuator operably coupled to move the pilot spool within the control spool. 3. The pilot valve as recited in claim 2 wherein the pilot piston has a tubular shape through which the control spool extends. 4. The pilot valve as recited in claim 2 further comprising a spring biasing the pilot spool with respect to the control spool. 5. The pilot valve as recited in claim 2 wherein the linear actuator is coupled to the pilot spool by a spring. 6. The pilot valve as recited in claim 2 wherein the pilot spool has a pair of grooves on an exterior surface through which fluid flows in selected positions of the pilot spool. 7. The pilot valve as recited in claim 2 wherein the pilot spool has a primary aperture and a plurality of exhaust apertures through which fluid flows to or from the second opening in the body in selected positions of the pilot spool. 8. The pilot valve as recited in claim 2 wherein the linear actuator is a stepper motor. 9. In a valve assembly having a control spool which selectively controls flow of fluid between at least one workport and both a supply passage and a return passage, a pilot valve comprising: a body with a piston bore into which a section of the control spool extends, a first opening into the bore communicates with one of the supply passage and the return passage, and a second opening into the bore communicates with the other of the supply passage and the return passage; a tubular pilot piston through which the control spool extends and is connected thereto, the pilot piston being slideably received in the piston bore thereby defining a first chamber and a second chamber in the piston bore, the pilot piston having a feeder aperture that communicates with the first opening in the body and with a first aperture in the control spool; a pilot spool slidably received in a pilot bore in the control spool and having a first position which opens a first passage between the first aperture in the control spool and the first chamber in the piston bore and opens a second passage between the first aperture and the second chamber in the piston bore, a second position which opens the first passage and a third passage between the second chamber and the second opening in the piston bore, and a third position which opens the second passage and a fourth passage between the first chamber and the second opening; and a linear actuator operably coupled to move the pilot spool within the control spool. 10. The pilot valve as recited in claim 9 further comprising a spring that biases the pilot spool with respect to the control spool. 11. The pilot valve as recited in claim 9 wherein the linear actuator is coupled to the pilot spool by a spring. 12. The pilot valve as recited in claim 9 wherein the pilot spool has a longitudinal primary aperture from which a first exhaust aperture and a second exhaust aperture extend to an outer surface, wherein the primary aperture and the first and second exhaust apertures at least partially form the third and fourth passages. 13. The pilot valve as recited in claim 12 wherein the control spool has first cross aperture and a second cross aperture both extending between an exterior surface and the pilot bore, wherein the first cross aperture cooperates with the first exhaust aperture to form the fourth passage, and the second cross aperture cooperates with the second exhaust aperture to form the third passage. 14. The pilot valve as recited in claim 9 wherein the pilot spool has a first exterior groove and a second exterior groove, wherein the first and second exterior grooves at least partially form the first passage and the second passage. 15. The pilot valve as recited in claim 14 wherein the control spool has a second aperture and a third aperture both extending between an exterior surface and the pilot bore, wherein the second aperture cooperates with the first exterior groove to form the first passage, and the third aperture cooperates with the second exterior groove to form the second passage. 16. The pilot valve as recited in claim 14 wherein the pilot piston has a first interior groove which cooperates with the second aperture of the control spool to form the first passage, and has a second interior groove which cooperates with the third aperture of the control spool to form the second passage.
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이 특허에 인용된 특허 (16)
Koehler Douglas W. (Naperville IL), Control system for a hydraulic circuit.
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