Active mounts for aircraft engines

• US 5,551,650 A
• Filed: 06/16/1994
• Issued: 09/03/1996
• Est. Priority Date: 06/16/1994
• Status: Expired due to Term

• Current Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Original Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Inventors: Southward, Steve C., Ivers, Douglas E.
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): DINH, TIEN QUANG
• Application Number:
  US08/260,945
• Time in Patent Office: 810 Days
• Field of Search: 244/54, 244/17.27, 244/1 N, 267/140.14, 267/140.15
• US Class Current: 244/54
• CPC Class Codes: F16F 1/40 consisting of a stack of similar elements separated by non-elastic intermediate layers F16F9/306 takes precedence; laminated constructions to protect buildings against abnormal external influences, e.g. earthquakes, E04H9/022
• CPC Class Codes: F16F 13/08 the plastics spring forming at least a part of the wall of the fluid chamber of the damper F16F13/20 - F16F13/24 take precedence
• CPC Class Codes: F16F 15/00 Suppression of vibrations in systems damping of non-rotary systems using inertia effect F16F7/10; prevention or isolation of vibrations in machine tools B23Q11/0032; suppression of driveline vibrations in hybrid vehicle transmissions B60W30/20 ; vehicle seat suspension devices B60N2/50; methods or devices for protecting against, or damping of, acoustic waves, e.g. sound G10K11/16; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion vibration absorbing or balancing means for aircraft propellers B64C11/008, for rotorcraft rotors B64C27/001 ; testing static and dynamic balance of machines or structures G01M1/00
• CPC Class Codes: F16F 15/027 comprising control arrangements F16F15/0237 takes precedence
• CPC Class Codes: F16F 15/08 with rubber springs grommet- or bushing-type resilient mountings F16F1/3732, F16F1/38; with springs made of rubber and metal arrangement of internal-combustion or jet-propulsion units B60K5/12; mounting of propulsion plants on vessels B63H21/30; mounting of vehicle drivers' cabs B62D33/0604
• CPC Class Codes: F16F 7/1005 characterised by active control of the mass
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17883 the reference signal being derived from a machine operating condition, e.g. engine RPM or vehicle speed
• CPC Class Codes: G10K 2210/107 Combustion, e.g. burner noise control of jet engines internal combustion engines G10K2210/121
• CPC Class Codes: G10K 2210/121 Rotating machines, e.g. engines, turbines, motors; Periodic or quasi-periodic signals in general
• CPC Class Codes: G10K 2210/123 Synchrophasors or other applications where multiple noise sources are driven with a particular phase relationship
• CPC Class Codes: G10K 2210/1281 Aircraft, e.g. spacecraft, airplane or helicopter
• CPC Class Codes: G10K 2210/129 Vibration, e.g. instead of, or in addition to, acoustic noise
• CPC Class Codes: G10K 2210/3016 Control strategies, e.g. energy minimization or intensity measurements
• CPC Class Codes: G10K 2210/321 Physical

Abstract

An active mount for fixed wing applications. One aspect of the invention provides decoupling of two tones which are close in frequency by positioning the mount actuators and error sensors in the primary transmission path of the disturbance vibration and by providing adequate spatial separation between the two sets of error sensors to reduce or eliminate cross-coupling of the signals. Another aspect of the invention utilizes orthogonally positioned actuators with corresponding actuators of paired mounts being focalized for each engine.

Claims

1. A system for minimizing vibration transmitted from a plurality of power plants, including a first power plant operating at a frequency N_1R and a second power plant operating at a frequency N_1L, where N_1R and N_1L are equal or nearly equal, into a passenger compartment of an aircraft, said system comprising

a) a first active mount securing a first of said power plants to a first portion of an aircraft structure, said first active mount including first actuator means;

b) a second active mount securing a second of said power plants to a second portion of said aircraft structure, said second active mount including second actuator means;

c) first sensor means mounted proximate said first power plant for detecting vibration induced by said first power plant and for producing a first signal representative thereof, said first sensor means being spaced sufficiently far away from said second power plant to minimize an influence of N_1L on said first signal;

d) second sensor means mounted proximate s aid second power plant for detecting vibration induced by said second power plant and for producing a second signal representative thereof, said second sensor means being spaced sufficiently far away from said first power plant to minimize an influence of N_1R on said second signal;

e) signal processing means for converting said first and second representative signals into first and second control signals for said first and second actuator means of said first and second active mounts, respectively;

whereby said first and second sensor means are positioned so as to decouple the response of said actuators to their respective first and second representative signals.

2. The system for minimizing vibration of claim 1 wherein said first and second portions of said aircraft structure to which said power plants are secured are positioned on opposite sides of said passenger compartment.

3. The system for minimizing vibration of claim 1 wherein said first and second sensor means each comprise a tachometer providing first and second input signals representative of N_1R and N_1L, respectively, and error sensor means representative of a level of vibration transmitted through said mount.

4. The system for minimizing vibration of claim 3 wherein said first and second error sensor means are positioned on the structure side of said mounts for said first and second power plants, respectively.

5. The system for minimizing vibration of claim 4 wherein said error sensor means are mounted in a primary disturbance path between said power plant and said support structure for its respective power plant.

6. The system for minimizing vibration of claim 5 wherein said first and second sensor means are capable of sensing frequency, phase and amplitude of said vibrations.

7. The system for minimizing vibration of claim 3 comprising a tonal control system in which said first tachometer detects a first operating frequency N_1R of said first power plant and produces a signal representative of N_1R and said second tachometer detects a second operating frequency N_1L of said second power plant and produces a signal representative of N_1L.

8. The system for minimizing vibration of claim 7 wherein said first and second control signals are phase shifted signals whose amplitude has been modified which are also representative of N_1R and N_1L input to said first and second actuator means, respectively, to cancel the vibrational effects of N_1R and N_1L.

9. The system for minimizing vibration of claim 8 wherein said actuator means comprises first and second orthogonal force transmission elements which are mounted such that each may deliver a force having a horizontal and a vertical component.

10. The system for minimizing vibration of claim 3 wherein said first and second power plants each produce a secondary disturbance tone N'"'"'_1R and N'"'"'_1L, respectively, and said system includes means to minimize transmission of vibration resulting from these secondary disturbance tones including third and fourth input signals provided by a tachometer.

11. A system for minimizing vibration transmitted from a plurality of power plants, including a first power plant operating at a frequency N_1R and a second power plant operating at a frequency N_1L, where N_1R and N_1L are equal or nearly equal, into a passenger compartment of an aircraft, said system comprising

a) a first sync signal generating means for producing a signal representative of disturbance signal N_1R ;

b) a second sync signal generating means for producing a signal representative of disturbance signal N_1L ;

c) first error sensor means mounted proximate said first power plant on a structural support for detecting vibration induced by said first power plant in said support and for producing a first signal representative thereof, said first error sensor means being spaced a sufficient distance from said second power plant so that the influence of N_1L on said first signal is minimal;

d) second error sensor means mounted proximate said second power plant on a structural support for detecting vibration induced by said second power plant in said support and for producing a second signal representative thereof, said second error sensor means being spaced a sufficient distance from said first power plant so that the influence of N_1R on said second signal is minimal;

e) a first output device for producing a counter-phased vibration to minimize the transmission of N_1R to its respective support structure;

f) a second output device for producing a counter-phased vibration to minimize the transmission of N_1L to its respective support structure;

g) signal processing means for receiving said first and second sync signals and said first and second representative signals and producing first and second control signals for said first and second output devices, respectively;

whereby said first and second error sensor means are positioned so as to decouple the response of said output devices to their respective first and second representative signals.