IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
UP-0500893
(2006-08-09)
|
등록번호 |
US-7631835
(2009-12-24)
|
우선권정보 |
FR-05 08497(2005-08-10) |
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
4 인용 특허 :
8 |
초록
▼
Solidborne noise and vibration is decoupled in a rotary wing aircraft by a laminated ball joint (15) for a suspension bar (13) of a transmission gearbox, the ball joint including at least two damper layers (19) dedicated to a frequency band for decoupling in the range 0 to 7000 Hz. For this purpose,
Solidborne noise and vibration is decoupled in a rotary wing aircraft by a laminated ball joint (15) for a suspension bar (13) of a transmission gearbox, the ball joint including at least two damper layers (19) dedicated to a frequency band for decoupling in the range 0 to 7000 Hz. For this purpose, the damper layers (19) and possibly also likewise dedicated interleaved layers (20) are given shape and/or dimension and/or physical-property parameters as a function of the frequency for decoupling in the determined frequency band.
대표청구항
▼
What is claimed is: 1. A method of decoupling solidborne noise and vibration applied to a rotary wing aircraft (1) in a laminated ball joint (15) between firstly a suspension bar (13) and secondly a force transmission structure (7) and/or a case (9) of a transmission gearbox (4) of the aircraft (1)
What is claimed is: 1. A method of decoupling solidborne noise and vibration applied to a rotary wing aircraft (1) in a laminated ball joint (15) between firstly a suspension bar (13) and secondly a force transmission structure (7) and/or a case (9) of a transmission gearbox (4) of the aircraft (1), the method comprising at least the step of preparing the laminated ball joint (15) the ball joint comprising at least an outer strap (17) and a junction shaft (18) for anchoring the ball joint (15) respectively to the force transmission structure (7) or to a transmission gearbox case, and at least two damper layers (19) and an interleaved rigid layer (20), wherein a determination step prior to the preparation step provides for determining at least one frequency band for decoupling in the range 0 to 7000 Hz, the step of preparing the laminated ball joint (15) comprising a stage of allocating frequencies such that said frequency-allocation stage provides for at least two damper layers (19) and at least one interleaved rigid layer (20) to be selected respectively for dedication to at least a determined frequency band, by imposing on said layers (19, 20) shape and dimension and physical-property parameters, said imposed parameters being such that the layers (19, 20) perform selective decoupling at least one frequency of the determined band. 2. A method according to claim 1, wherein said step prior to the preparation step provides for determining at least one frequency band for decoupling lying in the range 0 to 4000 Hz. 3. The method according to claim 1, wherein the step of preparing the laminated ball joint (15) comprises a stage of modeling at least the ball joint (15) by finite elements, and then a step of prior evaluation of at least one of the decoupling parameters of the damper layers (19) and/or the rigid layers (20) by using finite elements, with an attenuation value that is as large as possible as obtained in this way for the first natural frequency of the laminated ball joint (15) being used during the frequency allocation stage in order to actually compute the parameters imposed on the layers (19, 20). 4. The method according to claim 1, wherein the step of preparing the laminated ball joint (15) includes at least one stage of integrating contextual data selected from: the static stiffness of the components; the dynamic stiffness of the components; the damping of the components; the maximum acceptable static forces; the maximum acceptable dynamic forces; criteria concerning longevity and ability to withstand fatigue; certification requirements; maximum acceptable displacements for the components; maximum acceptable misalignments for the components; and the sizes and weights of the components. 5. The method according to claim 1, wherein the step of preparing the laminated ball joint (15) comprises, during the frequency allocation stage, at least one stage of computing parameters: for local shapes of the outer strap (17) of the ball joint (15), provided with a confinement casing (21) protecting the damper and rigid layers (19 and/or 20) against aggressive atmospheres; and for dimensions of said outer strap (17), in order to obtain large decoupling areas, by overdimensioning the strap (17) relative to mechanical and standards requirements. 6. The method according to claim 1, wherein the step of preparing the laminated ball joint (15) comprises at least one stage of deciding: the numbers of dedicated elastomer layers (19) and thus of interposed rigid layers; and the shape of each of the dedicated layers (19, 20), spherical, bullet-shaped; and the dimensions and the thickness of each of the dedicated layers (19, 20); and the materials specific to each of the dedicated layers (19, 20). 7. The method according to claim 1, wherein the determination step also includes a stage in which at least one additional frequency band for decoupling is determined, in spectra that are not audible to humans, in ultrasound or intrasound spectra. 8. The laminated ball joint (15) for decoupling solidborne noise in a rotary wing aircraft, the ball joint (15) being for providing a hinge connection between firstly a suspension bar (13) and secondly a force transmission structure (7) and/or a case (9) of a transmission gearbox (4) of the aircraft, said ball joint (15) comprising at least firstly an outer strap (17) and a junction shaft, the strap (17) and the shaft serving to anchor the ball joint (15) respectively to the force transmission structure (7) or to a gearbox casing (9), and secondly two damper layers (19) and an interleaved rigid layer (20), the ball joint (15) including at least two damper layers (19) and at least one rigid layer that are respectively arranged to be dedicated to at least a frequency band for decoupling lying in the range 0 to 7000 Hz, said layers presenting shape and dimension and/or physical-property parameters that are imposed to provide selective decoupling at least one frequency of the determined band. 9. The ball joint (15) according to claim 8, presenting parameters selected from: the static stiffness of its components; the dynamic stiffness of its components; the damping of its components; the maximum acceptable static loads; the maximum acceptable dynamic loads; criteria concerning longevity and ability to withstand fatigue; certification requirements; maximum acceptable displacements for the components; maximum acceptable misalignments for the components; and the sizes and weights of the components. 10. The ball joint (15) according to claim 8, presenting parameters selected firstly from local shapes for the outer strap (17), said strap (17) is provided with a confinement casing (21) protecting the damper layers (19) and the rigid layers (20) against aggressive atmospheres, and secondly from dimensions of said strap (17), e.g. such that the damper layers (19) and the rigid layers (20) possess extended decoupling surfaces that are overdimensioned relative to mechanical and standards requirements. 11. The ball joint (15) according to claim 8, presenting in section in longitudinal elevation, an outer profile that is substantially oval in shape, having an inner core (22) for receiving the junction shaft (18) with an outline that is substantially spherical and having an outer axial rim (23) projecting from the spherical outline. 12. The ball joint (15) according to claim 8, the ball joint having a receiver outer strap (17) of substantially rectangular section, possessing an axial dimension that is smaller than the corresponding dimension of an inner core (22) for receiving the junction shaft (18). 13. The ball joint (15) according to claim 8, the ball joint having at least three dedicated damper layers (19) of elastomer having an outline possessing a rectilinear edge that forms an angle (A) of about 5° to 15°. 14. A ball joint (15) according to claim 8, including at least three rigid layers (20) of a precipitation-hardened steel alloyed in particular with chromium (11% to 18% by weight), nickel, and copper. 15. The ball joint (15) according to claim 8, wherein the materials of the damper layers (19) and of the rigid layers are suitable for presenting properties that are compatible with the maximum constraints expected on the laminated ball joint (15), up to a temperature of about-50° C. to +110° C., in particular +80° C. 16. The ball joint (15) prepared using the decoupling method in accordance with claim 1. 17. A mechanical connection for selective and vibratory decoupling of solidborne noise for a rotary wing aircraft (1) between the transmission gearbox (4) and the destination force transmission structure (7), the connection comprising at least three suspension bars (13) extending in a downwardly-flared configuration in the elevation direction, together with at least two devices (10) against negative torque, wherein at least one of said suspension bar (13) includes the laminated ball joint (15) at least one of its ends hinged to the transmission gearbox (4) and/or to the force transmission structure (7), said laminated ball joint (15) being in accordance with claim 8. 18. A mechanical connection according to claim 17, wherein each of the suspension bars (13) of the mechanical connection is provided with the laminated ball joint (15), interposed between each of the ends hinged to the force transmission structure (7) and an anchoring fitting of said structure (7). 19. A mechanical connection according to claim 17, wherein the outer strap (17) of the laminated ball joint (15) is welded to the end of the suspension bar (13). 20. A mechanical connection according to claim 17, wherein the junction shaft (18) of the laminated ball joint (15) is connected to a fitting by screw fastening said fitting comprising a pair of plates for connection to the junction shaft interconnected by a web for fastening to an anchoring soleplate provided with releasable assembly means disposed in at least two intersecting planes, at least one of which is placed against the force transmission structure (7). 21. A rotary wing aircraft (1) such as a helicopter, including at least one mechanical connection in accordance with claim 17.
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