Active vibration isolation system

• US 9,145,946 B2
• Filed: 03/15/2013
• Issued: 09/29/2015
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Textron Innovations Incorporated (Textron Inc)
• Original Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Inventors: Heverly, David E. II, Lee, Taeoh
• Primary Examiner(s): Sanderson, Joseph W
• Application Number:
  US13/840,408
• Publication Number:
  US 20140263825A1
• Time in Patent Office: 928 Days
• US Class Current: 1/1
• CPC Class Codes: B64C 2027/002 mounted between the rotor drive and the fuselage
• CPC Class Codes: B64C 2027/004 using actuators, e.g. active systems
• CPC Class Codes: B64C 27/001 Vibration damping devices
• CPC Class Codes: F16F 15/027 comprising control arrangements F16F15/0237 takes precedence
• CPC Class Codes: F16F 15/0275 Control of stiffness
• CPC Class Codes: F16F 9/5126 Piston, or piston-like valve elements F16F9/504 takes precedence
• CPC Class Codes: Y02T 50/40 Weight reduction

Abstract

An apparatus includes an active vibration isolation system that includes a vibration isolator, a dual fluid pump in fluid communication with the vibration isolator and a hydraulic system, wherein the dual fluid pump is configured to segregate a tuning fluid from a hydraulic fluid and an electric-hydraulic servo valve in fluid communication with the dual fluid pump.

Claims

1. An apparatus comprising:

an active vibration isolation system, comprising;

a vibration isolator to flow a tuning fluid;

a dual fluid pump in fluid communication with the vibration isolator to flow the tuning fluid through the vibration isolator;

an electro-hydraulic servo valve in fluid communication with the dual fluid pump to provide a hydraulic fluid to drive he dual fluid pump, the dual fluid pump to segregate the tuning fluid from the hydraulic fluid; and

a hydraulic system configured to provide the hydraulic fluid to the electro-hydraulic servo valve.

2. The apparatus of claim 1, further comprising:

a fuselage;

an engine; and

a gearbox; and

wherein the active vibration isolation system is configured to attenuate a vibration from the engine, the gearbox or both.

3. The apparatus of claim 2, wherein the vibration isolator comprises a liquid inertia vibration eliminator (LIVE).

4. The apparatus of claim 2, further comprising a control computer configured to measure vibration within the fuselage and adjust the vibration isolator.

5. The apparatus of claim 4, wherein the electro-hydraulic servo valve is actuated in response to a signal communicated by the control computer.

6. The apparatus of claim 4, wherein the active vibration isolation system further comprises a displacement transducer configured to output a signal to the control computer corresponding to an axial position of a piston of the dual fluid pump.

7. The system of claim 4, wherein the control computer is in signal communication with one or more vibration sensors coupled to the fuselage.

8. The apparatus of claim 2, wherein the dual fluid pump is in fluid communication with the hydraulic system via the hydraulic fluid and wherein the dual fluid pump is in fluid communication with the vibration isolator via the tuning fluid.

9. The apparatus of claim 1, wherein the dual fluid pump of the active vibration isolation system comprises:

a housing;

a piston assembly having a first end, a second end and a flange disposed between the first and second ends; and

a pair of outer fluid chambers disposed at each end of the piston assembly, wherein a first outer fluid chamber of the pair of outer fluid chambers is disposed at the first end of the piston assembly, and a second outer fluid chamber of the pair of outer fluid chambers is disposed at the second end of the piston assembly, and wherein the outer fluid chambers are in fluid communication with the hydraulic system via the hydraulic fluid; and

a third fluid chamber disposed between the first end and the second end of the piston assembly, wherein the flange of the piston assembly is disposed within the third fluid chamber, and wherein the third fluid chamber is in fluid communication with the vibration isolator via the tuning fluid.

10. The apparatus of claim 1, wherein the dual fluid pump of the active vibration isolation system comprises:

a housing;

a piston assembly disposed within the housing, the piston assembly having a first end, a second end, a first outer flange disposed at the first end, a second outer flange disposed at the second end, and a pair of inner flanges disposed between the first and second outer flanges;

a pair of outer fluid chambers disposed at each end of the piston assembly, wherein a first outer fluid chamber of the pair of outer fluid chambers is disposed at the first end of the piston assembly, and a second outer fluid chamber of the pair of outer fluid chambers is disposed at the second end of the piston assembly, and wherein the pair of outer fluid chambers are in fluid communication with the vibration isolator via the tuning fluid;

a housing flange disposed axially between the pair of inner flanges that sealingly engages an outer surface of the piston assembly; and

a pair of inner fluid chambers disposed between the housing flange and each inner flange of the pair of inner flanges of the piston assembly, wherein the pair of inner fluid chambers are in fluid communication with the hydraulic system via the hydraulic fluid.

11. The apparatus of claim 1, wherein the dual fluid pump of the active vibration isolation system comprises a first pump and a second pump, each of the first pump and the second pump comprising:

a piston assembly having a first end, a second end, and a flange disposed between the first and second ends;

a first fluid chamber disposed at the first end of the piston assembly and in fluid communication with the hydraulic system via the hydraulic fluid; and

a second fluid chamber disposed at a face of the flange of the piston assembly and in fluid communication with the vibration isolator via the tuning fluid.

12. An active vibration control system for an aircraft, comprising:

a vibration isolator to flow a tuning fluid;

a dual fluid pump in fluid communication with both the vibration isolator and a hydraulic system of the aircraft, the dual fluid pump to flow the tuning fluid through the vibration isolator;

an electro-hydraulic servo valve in fluid communication with the dual fluid pump to provide a hydraulic fluid from the hydraulic system to drive the dual fluid pump, the dual fluid pump to segregate the tuning fluid from the hydraulic fluid; and

a control computer configured to measure vibration within a fuselage of the aircraft and be in signal communication with the vibration isolator and the dual fluid pump.

13. The system of claim 12, wherein the dual fluid pump is in fluid communication with hydraulic fluid of the hydraulic system and tuning fluid of the vibration isolator.

14. The system of claim 12, further comprising a displacement transducer configured to output a signal to the control computer corresponding to an axial position of a piston assembly of the dual fluid pump.

15. The system of claim 12, wherein the vibration isolator comprises a liquid inertia vibration eliminator (LIVE).

16. A method of isolating vibration from a gearbox using a vibration isolation system, the method comprising:

outputting a control signal communicated by a control computer to an electro-hydraulic servo valve;

communicating a first fluid between the electro-hydraulic servo valve and a dual fluid pump;

communicating a feedback signal to the control computer corresponding to a measured displacement of a piston assembly within the pump using a displacement transducer; and

communicating a second fluid between the vibration isolation system and the dual fluid pump, wherein the first fluid is segregated from the second fluid via the dual fluid pump.

17. The method of claim 16, wherein the gearbox is part of an aircraft fuselage, wherein the method further comprises:

measuring the position of the piston assembly of the dual fluid pump via the displacement transducer;

taking at least one vibration measurement from the fuselage using a vibration sensor;

transmitting a first signal corresponding to the vibration measurement to the control computer; and

transmitting a second signal corresponding to the measured position of the piston assembly of the dual fluid pump to the control computer.

18. The method of claim 17, further comprising processing the first signal corresponding to the vibration measurement and the second signal corresponding to the piston assembly position to form an output control signal.

19. The method of claim 16, further comprising actuating the electro-hydraulic servo valve in response to the control signal communicated by the control computer.