Antivibration suspension device for a mechanical element, and an aircraft

Abstract

A suspension device (10) provided with at least one suspension means (20) comprising a flapper (21) performing pendulum motion, the flapper (21) being provided with a mass support (25) supporting at least one flapping mass (30). The mass support (25) is hinged to a carrier structure (2) for isolating and to a holder bar (15) for holding said mechanical assembly. The suspension device (10) includes at least one force generator (70), said suspension device (10) having at least one computer (50) connected to a measurement system (55) measuring the levels of vibration, and to said force generator (70) to regulate said amplitude and said phase actively by controlling the force generator (70) as a function of at least one measurement signal coming from said measurement system (55).

Claims

1. An antivibratory suspension device for a mechanical assembly, the device comprising: a flapper performing pendulum motion, the flapper being provided with a mass support that extends from a distal end supporting at least one flapping mass to a proximal end, the proximal end being provided with a first hinge for hinging the mass support to a carrier structure for isolating; a second hinge for hinging a holder bar of the mechanical assembly to the mass support between the distal end and the proximal end; at least one dynamic force generator acting on an amplitude and phase of the pendulum motion of a flapper; a measurement system measuring a vibratory response of the carrier structure; and a computer in communication with the measurement system and the dynamic force generator, wherein the computer controls the dynamic force generator to adjust the amplitude and the phase of the flapper as a function of at least one measurement signal coming from the measurement system, wherein the at least one dynamic force generator includes at least one coil secured to the flapping mass and a magnetic mass, the magnetic mass being directly attached to the flapping mass by a resilient body.

2. The device according to claim 1, further comprising fastener means for fastening the at least one force generator to the carrier structure.

3. The device according to claim 1, further comprising a fastener system for fastening at least one force generator to the mechanical assembly.

4. The device according to claim 1, further comprising a fastener member for fastening at least one dynamic force generator to the flapper.

5. The device according to claim 1, wherein the at least one dynamic force generator is an electromagnetic actuator comprising a magnetic mass, at least one coil, and an electrical power amplifier connected to the coil and to the computer.

6. The device according to claim 5, wherein the coil is arranged on the flapping mass.

7. The device according to claim 1, wherein the measurement system includes attachment means for attachment to the carrier structure.

8. The device according to claim 1, wherein the at least one dynamic force generator is connected to the flapping mass.

9. The device according to claim 1, wherein the at least one dynamic force generator includes a piezoelectric member incorporated in the mass support.

10. The device according to claim 1, wherein the at least one dynamic force generator includes at least one pair of contra-rotating masses carried by the flapping mass.

11. The device according to claim 1, further comprising a resilient element connected to the flapper in order to provide stiffness between the mechanical assembly and the carrier structure.

12. The device according to claim 1, further comprising at least two flappers, wherein one force generator is provided for each flapper.

13. The device according to claim 12 further comprising one computer for each force generator.

14. An aircraft having a carrier structure and a mechanical assembly including a lift rotor and a main gearbox driving the lift rotor, the mechanical assembly including at least one holder bar extending from a top end hinged to the main gearbox to a bottom end, wherein the aircraft includes a suspension device according to claim 1, at least one bottom end of a holder bar being hinged to the second hinge of a suspension means of the suspension device.

15. The aircraft according to claim 14, wherein each holder bar is hinged to a flapper.

16. An aircraft comprising: a carrier structure; a mechanical assembly including a lift rotor and a main gearbox driving the lift rotor, the at least one holder bar extending from a top end hinged to the main gearbox to a bottom end; an antivibratory suspension device for the mechanical assembly, the antivibratory suspension device including: a flapper performing pendulum motion, the flapper being provided with a mass support that extends from a distal end supporting at least one flapping mass to a proximal end, the proximal end being provided with a first hinge for hinging the mass support to a carrier structure for isolating; a second hinge for hinging a holder bar of the mechanical assembly to the mass support between the distal end and the proximal end; at least one dynamic force generator acting on an amplitude and phase of the pendulum motion of a flapper; at least one computer connected to the at least one dynamic force generator and to a measurement system measuring a vibratory response of the carrier structure to adjust the amplitude and the phase actively by controlling the at least one dynamic force generator as a function of at least one measurement signal coming from the measurement system, wherein the at least one dynamic force generator includes at least one coil secured to the flapping mass and a magnetic mass, the magnetic mass being directly attached to the flapping mass by a resilient body, with at least one bottom end of the holder bar being hinged to the second hinge of a suspension means of the suspension device.

17. An aircraft comprising: a carrier structure; a mechanical assembly including a lift rotor and a main gearbox driving the lift rotor; a holder bar hinged at a top end to the main gearbox and extending to a bottom end; an antivibratory suspension device for the mechanical assembly, the antivibratory suspension device including: a flapper hinged to the carrier structure at a proximal end to act in pendulum motion, the flapper having at least one flapping mass supported on a distal end; a second hinge for hinging the at least one holder bar to the flapper; a dynamic force generator acting on an amplitude and phase of the pendulum motion of a flapper; a measurement system measuring a vibratory response of the carrier structure; a computer in communication with the measurement system and the dynamic force generator, wherein the computer controls the dynamic force generator to adjust the amplitude and the phase of the flapper based on the measured vibratory response of the carrier structure, wherein the dynamic force generator includes at least one coil secured to the flapping mass and a magnetic mass, the magnetic mass being directly attached to the flapping mass by a resilient body.

18. The aircraft according to claim 17, wherein a center of mass of the flapper is located between the second hinge and the distal end.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The invention and its advantages appear in greater detail from the following description of embodiments given by way of illustration and with reference to the accompanying figures, in which:

(2) FIG. 1 is a diagrammatic view of an aircraft of the invention;

(3) FIG. 2 is a diagrammatic view of a suspension device; and

(4) FIGS. 3 to 9 are diagrammatic views of embodiments of a suspension device of the invention.

(5) Elements present in more than one of the figures are given the same references in each of them.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 shows an aircraft 1 including a carrier structure 2. The aircraft 1 also has a mechanical assembly 3 fastened to the carrier structure 2 in order to contribute in particular to providing the aircraft 1 with lift.

(7) The mechanical assembly 3 includes a lift rotor 5, a main gearbox (MGB) 4 of the mechanical assembly 3 being interposed between the lift rotor 5 and a power plant that is not shown in the figures.

(8) The aircraft is shown in deliberately incomplete manner in the figures in order to avoid overloading the figures.

(9) The main gearbox 4 rests on the carrier structure 2 via a diaphragm 300 that takes up torque and enables the transmission to move.

(10) The aircraft 1 has a suspension device serving firstly to reduce the amount of vibration that is transmitted by the mechanical assembly 3, and secondly to fasten the mechanical assembly 3 to the carrier structure.

(11) The mechanical assembly 3 includes at least one holder bar 15, and indeed at least three holder bars 15 for fastening it to the carrier structure. Each holder bar extends from a top end 16 to a bottom end 17. Each top end 16 is hinged to the main gearbox 4 and in particular to a top portion of the main gearbox 4, while each bottom end 17 is connected indirectly to the carrier structure 2.

(12) Under such circumstances, the suspension device comprises at least one suspension means 20 interfaced between a holder bar 15 and the carrier structure 2. For example the suspension device comprises one suspension means per holder bar hinged to the carrier structure and to the bottom end 17 of the corresponding holder bar.

(13) Each suspension means 20 includes a flapper 21 having support means 25 supporting a flapping mass 30 (or fly weight, or masse battante in French language) and the bottom end 17 of a suspension bar. The support means 25 may be a lever or a blade.

(14) FIG. 2 shows a suspension means 20 of the invention in detail.

(15) The support means 25 may comprise a flat zone 25 extended by two longitudinal arms 28 that are connected together by a transverse arm 29 so as to present an H-shape. The flapper then extends longitudinally from a proximal end 27 to a distal end 26.

(16) The flapping mass is then carried by the distal end 26 of the flapper.

(17) Furthermore, the proximal end 27 is provided with a first hinge 35 enabling the support means 25 to be hinged to the carrier structure 2.

(18) The first hinge 35 may optionally include a pivot connection enabling the support means and thus the flapping mass 30 to pivot about a first direction AX1.

(19) Consequently, the first hinge may comprise a fitting 60 suitable for being fastened to the carrier structure 2. A first pivot axis 36 of the first hinge may then pass through at least one cheekplate 61 of the fitting 60.

(20) In addition, the suspension means includes a second hinge 40 for hinging a holder bar 15 to the support means 25 close to the first hinge. For example, the second hinge 40 is arranged in a zone lying between the center of gravity Cg of the flapper and the first hinge 35.

(21) This second hinge 40 may include at least one pivot connection. The second hinge may advantageously be a ball joint having a second connection axis 42 represented by the transverse arm 29. The second connection axis 42 passes through a spherical internal portion 43 of a ball joint, this spherical internal portion 43 being arranged in a cage 44 of the bottom portion 17 of the holder bar 15.

(22) The second connection axis 42 extends along a second direction AX2 parallel to the first axis AX1.

(23) The second hinge 40 is offset relative to the first hinge 35, thus kinematically amplifying the movement of the flapping mass 30 that is caused by the relative movement between the carrier structure 2 and the main gearbox 4.

(24) The suspension device also includes one resilient element 200 per suspension means, which element serves to provide the stiffness necessary for taking up the static forces that pass via the holder arms 15. The resilient element 200 is constituted in FIG. 1 by a blade working in bending that is secured to the arms 28 of the flapper and that rests at its end on the bottom 4 of the main gearbox. In other variants, the resilient element 200 may be constituted by a torsion tube mounted at the first hinge 35 between the fitting 60 and the flapper 21, or indeed by a spring arranged between a flapper 21 and the carrier structure, for example.

(25) Furthermore, the suspension device may include at least one force generator 70 for controlling the amplitude and the phase of the oscillating motion of a flapper 21.

(26) With reference to FIG. 1, the suspension device 10 may have a force generator 70 incorporated in each suspension means. The force generator is an actuator that may be hydraulic, pneumatic, electromechanical, electromagnetic, or indeed piezoelectric.

(27) The suspension device 10 also has at least one computer 50 connected to a measurement system 55 measuring the vibratory response of the carrier structure by means of accelerometers or force sensors. For example, accelerometers are adhesively bonded to the carrier structure 2.

(28) Each force generator 70 then communicates with a computer 50, the computer 50 actively controlling the amplitude and the phase of the motion of the flapper by issuing orders to the force generator 70 as a function of at least one measurement signal coming from the measurement system 55.

(29) The suspension device may include a respective computer for each force generator 70, or indeed a single computer 50 controlling all of the force generators 70 of the suspension device 10.

(30) With reference to FIGS. 3 to 9, the suspension device may comprise: fastener means 70 for fastening at least one force generator 70 to the carrier structure 2; a fastener system 70 for fastening at least one force generator 70 to the mechanical assembly 3; and a fastener member 70 for fastening at least one force generator 70 to the flapper.

(31) Thus, as shown in FIG. 3, the force generator 70 may be interposed between the flapper and the mechanical assembly 3 by being attached to each of them by conventional means.

(32) In this configuration, the distance d between the first hinge 35 and the attachment point of the force generator 70 to the mass support 25 is advantageously maximized in order to reduce the forces that need to be delivered.

(33) As shown in FIG. 4, the force generator 70 may be interposed between the flapper and the carrier structure 2 by being attached to each of them by conventional means.

(34) As shown in FIG. 5, the force generator 70 may be interposed between the mechanical assembly 3 and the carrier structure 2 by being attached to each of them by conventional means.

(35) As shown in FIGS. 6 to 9, the force generator 70 is connected to the distal end 26 of the flapper, and thus to the flapping mass.

(36) In FIG. 6, the force generator 70 is interposed between the mechanical assembly 3 and the flapping mass.

(37) For example, the force generator 70 includes an electromagnetic actuator 75 that comprises a magnetic mass 76 fastened to the main gearbox 4. In addition, the electromagnetic actuator 75 has at least one coil 77 fastened to the flapping mass 30, and possibly an electrical power amplifier 78 connected to said coil 77 and to said computer 50. The coil 77 and the flapping mass may constitute a single physical entity.

(38) As shown in FIGS. 7 to 9, the force generator is merely attached to the distal end of the suspension means.

(39) FIG. 7 shows a force generator provided with at least one coil 77 secured to the flapping mass 30. In addition, the force generator has a magnetic mass 76 resiliently attached to the flapping mass 30 by a resilient body 78, such as a spring. The magnetic mass is then movable relative to the flapping mass. Each coil may extend in a housing in the magnetic mass.

(40) Each coil 77 then communicates with a computer 50 optionally via a power amplifier.

(41) FIG. 8 shows a force generator that is provided with a piezoelectric member 80. This electromagnetic actuator 75 is incorporated in the mass support 25 and carries the flapping mass 30.

(42) FIG. 9 shows a force generator having two contrarotating masses 86 and 87 carried by the flapping mass 30. At least one motor 85 causes the contrarotating masses to rotate. A motor can thus adjust the angular phase offsets between the contrarotating masses.

(43) Naturally, the present invention may be subjected to numerous variations as to its implementation. Although several embodiments are described, it will readily be understood that it is not conceivable to identify exhaustively all possible embodiments. It is naturally possible to envisage replacing any of the means described by equivalent means without going beyond the ambit of the present invention.