A rotor system vibration absorber for use with a helicopter of other rotorcraft is disclosed in which spring forces are provided by a plurality of elongated rods arranged in a selected pattern. The rods are coupled at one end to a fixed base that is coupled to a rotor hub, and at the other end to a
A rotor system vibration absorber for use with a helicopter of other rotorcraft is disclosed in which spring forces are provided by a plurality of elongated rods arranged in a selected pattern. The rods are coupled at one end to a fixed base that is coupled to a rotor hub, and at the other end to a tuning weight.
대표청구항▼
The invention claimed is: 1. A rotorcraft comprising: a fuselage; a drive means carried by the fuselage; a rotor system including a rotor hub and rotor blades, the rotor system being coupled to the drive means; and a spring-mass vibration absorber comprising: a base member coupled to the rotor syst
The invention claimed is: 1. A rotorcraft comprising: a fuselage; a drive means carried by the fuselage; a rotor system including a rotor hub and rotor blades, the rotor system being coupled to the drive means; and a spring-mass vibration absorber comprising: a base member coupled to the rotor system; a tuning weight; and a plurality of elongated rods disposed between the base member and the tuning weight; wherein the rods serve as the spring and the tuning weight serves as the mass such that vibration from the rotor system is absorbed by the oscillatory deflection of the rods and the tuning weight. 2. The rotorcraft according to claim 1, wherein the spring rate of the vibration absorber is determined by selectively tailoring the number, location, size, and shape of the rods. 3. The rotorcraft according to claim 1, wherein the vibration absorber absorbs vibratory hub shear forces. 4. The rotorcraft according to claim 1, wherein the vibration absorber absorbs vibratory hub moments. 5. The rotorcraft according to claim 1, wherein the vibration absorber absorbs both vibratory hub shear forces and vibratory hub moments. 6. The rotorcraft according to claim 1, wherein the vibration is the principal blade-passage frequency. 7. The rotorcraft according to claim 1, wherein the rods are composite rods manufactured from a unidirectional composite fiber reinforced material. 8. The rotorcraft according to claim 7, wherein the composite rods are covered with a composite fabric to minimize delamination. 9. The rotorcraft according to claim 1, wherein the rods have a uniform cross-sectional geometry. 10. The rotorcraft according to claim 1, wherein the rods have a non-uniform cross-sectional geometry. 11. The rotorcraft according to claim 10, wherein the rods have a longitudinal profile in the shape of a non-linear function. 12. The rotorcraft according to claim 11, wherein the non-linear function is a cubic function. 13. The rotorcraft according to claim 1, wherein the base member is coupled to the rotor system above the rotor hub and the tuning weight is disposed above the rotor hub. 14. The rotorcraft according to claim 1, wherein the base member is coupled to the rotor system below the rotor hub and the tuning weight is disposed below the rotor hub. 15. The rotorcraft according to claim 1, wherein the base member is coupled to the rotor system above the rotor hub and the tuning weight is disposed below the rotor hub. 16. The rotorcraft according to claim 1, wherein the base member is coupled to the rotor system below the rotor hub and the tuning weight is disposed above the rotor hub. 17. The rotorcraft according to claim 1, further comprising: a second vibration absorber comprising: a second base member coupled to the rotor system; a second tuning weight; and a second plurality of elongated rods disposed between the second base member and the second tuning weight; wherein vibration from the rotor system is also absorbed by deflection of the second plurality of rods. 18. The rotorcraft according to claim 17, wherein the base member is coupled to the rotor system above the rotor hub and the tuning weight is disposed above the rotor hub; and wherein the second base member is coupled to the rotor system below the rotor hub and the second tuning weight is disposed below the rotor hub. 19. A vibration absorber for use on a rotorcraft having a rotor system including a drive means, a drive mast coupled to the drive means, a rotor hub coupled to the drive mast, and rotor blades pivotally coupled to the rotor hub, the vibration absorber comprising: a housing adapted for mounting to the underside of the rotor hub; a base member coupled to the housing; a tuning weight disposed above the rotor hub; and a plurality of rods, each rod being coupled at one end to the base member and coupled at the other end to the tuning weight; wherein the vibration absorber absorbs both vibratory hub shear forces and vibratory hub moments generated by the rotor system. 20. The vibration absorber according to claim 19, wherein one rod is disposed between each pair of adjacent rotor blades. 21. The vibration absorber according to claim 19, further comprising: an upper plate disposed between the rods and the tuning weight; wherein the upper ends of the rods are coupled to the upper plate, and the tuning weight is coupled to the upper plate. 22. The vibration absorber according to claim 21, further comprising: a travel stop means disposed on the upper plate and operably associated with the drive mast to prevent the vibration absorber from damaging the rotor system in the event of failure of the vibration absorber. 23. The vibration absorber according to claim 19, wherein the rods are composite rods manufactured from a unidirectional composite fiber reinforced material. 24. The vibration absorber according to claim 23, wherein the composite rods are covered with a composite fabric to minimize delamination. 25. The vibration absorber according to claim 19, further comprising: a canopy disposed over the vibration absorber to reduce aerodynamic drag generated by the vibration absorber. 26. The vibration absorber according to claim 19, wherein each rod comprises: an elongated body portion manufactured from a unidirectional fiber reinforced pultruded composite material; and a longitudinal profile in which each half of each rod is in the shape of a non-linear function, such that the ends have enlarged cross-sectional areas at the couplings to the base member and the tuning weight, and the smallest cross-sectional area is located at the longitudinal midpoint of each rod; whereby the fatigue life of each rod is increased and the greatest vibratory hub shear forces are located at the longitudinal midpoint of each rod. 27. The vibration absorber according to claim 26, wherein the non-linear function is a cubic function. 28. The vibration absorber according to claim 19, wherein the blade-passage frequency vibration is reduced. 29. A composite spring-mass assembly comprising: a fixed body; at least one elongated composite rod attached at one end to the fixed body, the composite rod being manufactured from a unidirectional fiber reinforced pultruded composite material; a movable mass attached to the other end of the composite rod, such that the movable mass is cantilevered relative to the fixed body; wherein the spring rate of the composite spring-mass system is determined by selectively tailoring the number, arrangement, and shape of the rods. 30. The composite spring-mass system according to claim 29, wherein each end of each elongated composite rod is tapered in the shape of a non-linear function, such that both ends of each composite rod have enlarged cross-sectional areas and the longitudinal midpoint has the smallest cross-sectional area. 31. The composite spring-mass system according to claim 30, wherein the non-linear function is a cubic function.
연구과제 타임라인
LOADING...
LOADING...
LOADING...
LOADING...
LOADING...
이 특허에 인용된 특허 (8)
Rogers Charles W. (Arlington TX) Crane David A. (Fort Worth TX) Rai Habib G. (Bedford TX), Continuous process of making unidirectional graphite fiber reinforced pultruded rods having minimal fiber waviness.
Vukorpa Victor M. (St. Joseph MI) Debrecht Douglas C. (St. Charles MO) Wells Larry B. (St. Louis MO) Dohogne L. Ranney (Creve Coeur MO) Newberg Barry M. (Florissant MO), Tuned dynamic vibration absorber.
Rogers Charles W. (Arlington TX) Crane David A. (Fort Worth TX) Rai Habib G. (Bedford TX), Unidirectional carbon fiber reinforced pultruded composite material having improved compressive strength.
Maresh, Andrew; Stamps, Frank Bradley; Tisdale, Patrick Ryan; Wardlaw, Robert Patrick; Haldeman, Andrew; Sutton, Drew Alan, Composite rotor system using two race track style cantilevered yokes.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.