Antivibration suspension system for a tie bar of an aircraft power transmission gearbox, an antivibration suspension system, and an aircraft

Abstract

An antivibration suspension system of an aircraft, the antivibration suspension system comprising a lever and an oscillating mass. The antivibration suspension system comprises a mechanical motion amplifier device interposed between the lever and the oscillating mass, the motion amplifier device being provided both with a mechanical inlet constrained to move in rotation with the lever about a control axis and with a mechanical outlet driving rotary movement of the oscillating mass.

Claims

1. An antivibration suspension system for suspending a tie bar of a power transmission gearbox of an aircraft, the antivibration suspension system comprising a lever hinged to the tie bar, the antivibration suspension system including an oscillating mass, wherein the antivibration suspension system comprises a mechanical motion amplifier device interposed between the lever and the oscillating mass so that a first rotary movement of the lever through a first angle about a control axis induces a second rotary movement of the oscillating mass through a second angle, the second angle being greater than the first angle, the motion amplifier device being provided both with a mechanical inlet constrained to move in rotation with the lever about the control axis and with a mechanical outlet driving rotary movement of the oscillating mass.

2. An antivibration suspension system according to claim 1, wherein the oscillating mass comprises a weight element carried by at least one rod, the at least one rod extending radially relative to a circle described by the weight element during the second rotary movement, each of the at least one rod being secured to the mechanical outlet.

3. An antivibration suspension system according to claim 2, wherein the weight element extends circumferentially relative to the circle.

4. An antivibration suspension system according to claim 1, wherein the motion amplifier device comprises a sun stage in contact with a plurality of identical planets, the sun stage comprising the mechanical outlet, the planets being carried by a planet carrier secured to the lever, the mechanical inlet comprising the planet carrier, the motion amplifier device including a ring, each planet extending diametrically from the sun stage to the ring.

5. An antivibration suspension system according to claim 4, wherein the ring is secured to a casing of the antivibration suspension system.

6. An antivibration suspension system according to claim 4, wherein each planet presents a diameter greater than the diameter of the sun stage.

7. An antivibration suspension system according to claim 4, wherein each planet includes peripheral teeth meshing with teeth of the sun stage and with teeth of the ring.

8. An antivibration suspension system according to claim 4, wherein each planet includes a peripheral coating of polyurethane in contact against a peripheral coating of the sun stage and with a peripheral coating of the ring.

9. An antivibration suspension system according to claim 4, wherein the motion amplifier device comprises an epicyclic train.

10. An antivibration suspension system according to claim 4, wherein the planet carrier has one pin per planet, each pin being secured to the lever, the planet carrier having a holder plate secured to each pin, each planet being arranged about a respective pin and being movable in rotation about its pin between the holder plate and the lever.

11. An antivibration suspension system according to claim 1, wherein the antivibration suspension system includes a casing provided with a fastener member suitable for fastening the casing to a carrier structure of an aircraft, the motion amplifier device being connected to the lever inside the casing, the lever projecting in part from the casing through an opening in the casing.

12. An antivibration suspension system according to claim 1, wherein the antivibration suspension system includes a torsion tube, the torsion tube extending from a first end secured to the lever to a second end that is prevented from rotating relative to the control axis.

13. An antivibration suspension structure of a mechanical assembly having at least one lift rotor and a power transmission gearbox, the antivibration suspension structure having at least three tie bars, each tie bar being hinged via a top end to the power transmission gearbox and via a bottom end to an antivibration suspension system, wherein at least one antivibration suspension system is a system according to claim 1.

14. An antivibration suspension structure according to claim 13, wherein each tie bar is hinged to an antivibration suspension.

15. An aircraft having a carrier structure and a mechanical assembly comprising a lift rotor and a power transmission gearbox for driving the lift rotor in rotation, wherein the aircraft includes an antivibration suspension structure according to claim 13.

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 antivibration suspension means;

(4) FIG. 3 is a three-dimensional view of an antivibration suspension system;

(5) FIG. 4 is a diagram explaining an amplifying motion device having a gear device;

(6) FIG. 5 is a diagram explaining an amplifying motion device having a friction device; and

(7) FIGS. 6 and 7 are a face view and an exploded view of an embodiment of an antivibration suspension system.

DETAILED DESCRIPTION OF THE INVENTION

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

(9) FIG. 1 shows an aircraft 1 having a carrier structure 2. The aircraft 1 is also provided with a mechanical assembly 3 carried by the carrier structure 2 in order to contribute in particular to providing the aircraft 1 with lift.

(10) The mechanical assembly 3 includes a lift rotor 5, a power transmission gearbox 4 of the mechanical assembly 3 being interposed between the lift rotor 5 and a power plant that is not shown in the figures. Under such circumstances, the power transmission gearbox 4 drives rotation of the lift rotor.

(11) The aircraft 1 has an antivibration suspension structure for connecting the mechanical assembly 3 to the carrier structure while reducing the vibration and the noise generated by the mechanical assembly 3.

(12) The antivibration suspension structure may comprise stiffeners 600 and/or dampers. For example, the antivibration suspension structure includes flexible blades 602 or a conventional resilient system 601 extending between the bottom of the power transmission gearbox and the carrier structure.

(13) Furthermore, the antivibration suspension structure includes at least one tie bar 15, or indeed at least three tie bars 15. Each tie bar then extends from a top end 16 to a bottom end 17. Each top end 16 is hinged to the gearbox 4 and in particular to the top portion of the power transmission gearbox 4. Conversely, each bottom end 17 is hinged to an antivibration suspension system forming an interface between the tie bar 15 and the carrier structure 2.

(14) At least one antivibration suspension system is an antivibration suspension system 20 of the invention.

(15) The antivibration suspension system 20 comprises a lever 25 that extends longitudinally from a proximal end 27 to a distal end 26. The lever 25 is carried by a casing 21 of the antivibration suspension system 20. In the embodiment of FIG. 1, the lever 25 thus passes through an opening 24 in the casing 21 in order to arrange its proximal end 27 inside the casing 21 and its distal end 26 outside the casing 21.

(16) Furthermore, a segment of the lever 25 situated in particular outside the casing 21 is hinged via a hinge to a tie bar 15. By way of example, a ball-joint type hinge is used. More precisely, the distal end 26 of the lever 25 is hinged to the bottom end 17 of a tie bar.

(17) Furthermore, the antivibration suspension system 20 comprises a motion amplifier device 40 arranged between the lever 25 and an oscillating mass 30.

(18) In addition, the casing 21 may include a conventional fastener member 90 for securing to the carrier structure 2. By way of example, the fastener member 90 comprises conventional adhesive, screw fastener, welding, stapling, . . . means.

(19) FIG. 2 is a diagram illustrating an antivibration suspension system 20 of the invention, with FIG. 3 being a three-dimensional view of an antivibration suspension system 20.

(20) With reference to FIG. 2, the casing 21 may have a bearing 22 or the equivalent for carrying the lever 25 without impeding a degree of freedom of the lever 25 to move in rotation about a control axis 100.

(21) In addition, the antivibration suspension system 20 comprises a motion amplifier device 40 that is possibly arranged inside the casing 21. The motion amplifier device 40 is provided with a mechanical inlet 45 that is constrained to move in rotation with the lever 25 about the control axis 100. By way of example, the mechanical inlet 45 is secured to the proximal end 27 of the lever 25 by conventional adhesive, screw fastener, welding, stapling, . . . means.

(22) Furthermore, the motion amplifier device 40 is provided with a mechanical outlet 50 that is movable in rotation about an outlet axis. For example, this outlet axis coincides with the control axis 100. The mechanical outlet 50 may be carried by a bearing 23 or the equivalent of the casing 21.

(23) Furthermore, the mechanical outlet 50 is constrained to move in rotation with an oscillating mass 30 in the sense that the mechanical outlet serves to drive rotary movement of the oscillating mass 30. In particular, the mechanical outlet 50 and the oscillating mass 30 can move together in rotation about the outlet axis, and more particularly about the control axis shown in FIG. 2.

(24) Under such circumstances, the motion amplifier device amplifies a first rotary movement ROT1 performed by the lever in order to generate a greater-amplitude second rotary movement ROT2 of the oscillating mass.

(25) By way of illustration, the lever may perform a first rotary movement ROT1 through a first angle, i.e. a first amplitude of the order of a few degrees. Within a motion amplifier device of the invention presenting an amplification ratio of about 10, the oscillating mass then performs a second rotary movement ROT2 over a second angle, i.e. a second amplitude of the order of a few tens of degrees.

(26) The motion amplifier device 40 may comprise a gear train. For example, the gear train may be a cycloidal train or an epicyclic train.

(27) FIG. 2 shows a motion amplifier device 40 comprising an epicyclic gear train 500.

(28) The motion amplifier device 40 thus comprises a sun stage 51 having a sun wheel 52 co-operating with a plurality of identical planets 60. Furthermore, the planets 60 are all carried by a planet carrier 46 representing the mechanical inlet 45 of the motion amplifier device.

(29) The planet carrier 46 is constrained to move in rotation with the lever 25 about the control axis 100.

(30) The planet carrier 46 thus has one pin 47 per planet 60. Consequently, the pins 47 are secured to the lever 25 by conventional means, and in particular they are secured to the proximal end 27 of the lever 25. The planet carrier 46 and the lever 25 may possibly form a single mechanical part.

(31) Under such circumstances, each planet is arranged on a respective pin 47 while being free to rotate about the pin 47. For example, bearing means 620 may be interposed between each planet and the corresponding pin.

(32) By way of example, such planets 60 comprise cylinders 61. More precisely, each planet 60 extends over a diameter referred to as the planet diameter D2.

(33) Furthermore, the planet carrier 46 of FIG. 2 has a holder plate 48 that is secured to each pin 47. Each planet 60 is thus arranged around a pin 47 and is free to move in rotation about the pin 47 between the holder plate 48 and the lever 25.

(34) The motion amplifier device 40 also has a ring 70 in contact with the planets 60.

(35) Consequently, each planet 60 extends diametrically from the ring 70 towards the sun stage 51. The ring 70 is secured to the casing 21, and the ring may be a portion constituting the casing 21.

(36) The sun stage 51 is thus arranged at least in part in the middle of the planets.

(37) By way of example, the sun stage 51 comprises a sun wheel 52 that co-operates with the planet, e.g. a cylinder. The sun wheel is then extended by an elongate portion 53 representing the mechanical outlet that is connected to the oscillating mass. The elongate portion 53 is optionally carried by the casing 21 via a bearing 23 which may be a rolling bearing or the equivalent.

(38) In addition, the sun stage and in particular its sun wheel 52 extends over a diameter referred to as the sun diameter D1.

(39) Under such circumstances, the planet diameter D2 is greater than the sun diameter D1.

(40) In the embodiment of FIG. 4, each planet 60 has teeth 62 at its periphery that mesh with teeth 54 of the sun wheel 52 of the sun stage 51 and with teeth 71 of the ring 70.

(41) In the embodiment of FIG. 5, each planet 60 has a peripheral coating 63 of polyurethane on its periphery. This peripheral coating 63 rubs against a peripheral coating 55 of the sun stage 51 and a peripheral coating 72 of the ring.

(42) Furthermore, and with reference to FIG. 3, the sun stage 51 represents the mechanical outlet 50 driving rotary movement of the oscillating mass 30.

(43) Under such circumstances, and with reference to FIG. 3, the oscillating mass 30 may comprise at least one rod 32 secured to the sun stage 51, and in particular to its elongate portion 53. Each rod extends radially relative to a circle 400 described by the weight element.

(44) A weight element 31 of the oscillating mass is then carried by each rod 32. The weight element is thus radially offset from the outlet axis about which the weight element oscillates with rotary motion.

(45) In particular, the weight element extends circumferentially relative to said circle 400.

(46) Consequently, when the tie bar hinged to the lever 25 is excited longitudinally under the effect of vibration, the lever performs a first rotary movement ROT1 about a middle position 200 through a first angle ANG1.

(47) The rotary movement of the lever 25 about the control axis 100 gives rise to rotation of each planet about the control axis 100 and about the corresponding pin. In addition, the planet drives rotation of the sun stage 51 about the control axis 100.

(48) The sun stage 51 then causes said oscillating mass 30 to perform a second rotary movement ROT2 about a middle position through a second angle ANG2. The second angle ANG2 is then greater than the first angle ANG1.

(49) Furthermore, the antivibration suspension system may include a torsion tube 80.

(50) The torsion tube 80 extends from a first end 81 that is secured to the lever 25 to a second end 82. The second end 82 is prevented from moving in rotation about the control axis 100, e.g. being secured to the casing 21.

(51) FIGS. 6 and 7 show an embodiment of the invention.

(52) In this embodiment, and with reference to FIG. 6, the oscillating mass 30 may comprise a weight element of any shape and in particular of cylindrical shape.

(53) Furthermore, the casing 21 may have a plate 700 suitable for being fastened by conventional fastener members 90 to a carrier structure.

(54) Each plate 700 possesses projections 701, 702, and 703.

(55) Under such circumstances, the casing may comprise a hollow cylinder 21 in which the torsion tube 80 extends. By way of example, the cylinder 21 is screw-fastened via three points to two rear projections 702.

(56) Furthermore, the casing 21 may include an end wall 21 provided with ring 70. By way of example, this end wall 21 is screw-fastened at three points to two front projections 701. The end wall 21 may possess a bearing 23 carrying the sun stage 51.

(57) In addition, the plate 700 includes a central projection 703, with the proximal end 27 being hinged to the central projection 703.

(58) 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.