Vibration isolating device for an elastic coupling of two components

A vibration isolating device that is adapted for an elastic coupling of a first component to a second component and for vibration isolation in predetermined frequency ranges between the first and second components, the vibration isolating device comprising at least a first and a second elastically deformable plate that are attached to each other in at least two separate connecting points, the first elastically deformable plate comprising a first curvature and the second elastically deformable plate comprising a second curvature, wherein the first and second curvatures are respectively located in a region between the at least two separate connecting points and arranged such that a gap is defined between the first and second elastically deformable plates.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to European patent application No. EP 15400027.7 filed on Jun. 29, 2015, the disclosure of which is incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The invention is related to a vibration isolating device that is adapted for an elastic coupling of a first component to a second component and for vibration isolation in predetermined frequency ranges between said first and second components, said vibration isolating device comprising the features of claim1. The invention is further related to a helicopter with a first component that is elastically coupled to a second component by means of such a vibration isolating device, said helicopter comprising the features of claim17.

(2) Description of Related Art

Vibration isolating devices that are adapted for an elastic coupling of two components and for vibration isolation in predetermined frequency ranges between these two components can e.g. be used in a helicopter for an elastic coupling between its main gear box and its fuselage. In this case, the vibration isolating devices are used to transmit static forces and torques that are acting on the helicopter's main rotor and, thus, on the main gear box, between the main gear box and the fuselage. They are further used to provide an effective damping or filtering action against the dynamic components of the transmitted static forces and torques acting via the main rotor on the main gear box in order to avoid occurrence of destructive vibration conditions in operation.

However, it should be noted that such vibration isolating devices are not only suitable for use in helicopters, but for use in any rotary wing aircraft and, generally, in aircrafts as a whole. Even more generally, such vibration isolating devices can be used everywhere where two components are to be coupled and where vibration isolation is necessary. In other words, such vibration isolating devices cannot only be used in aerospace engineering, but also in other technical domains such as automotive engineering, machinery and so on.

Accordingly, such vibration isolating devices are widely used today. By way of example, several conventional vibration isolating devices are described hereinafter.

The document U.S. Pat. No. 6,283,408 describes an anti-vibration suspension device for a main rotor of a helicopter that comprises a rotor mast driven in rotation by a main gear box about an axis of the mast, which is the axis of rotation of the rotor, i.e. the rotor axis. This anti-vibration suspension device includes at least three rigid and oblique bars for supporting the main gear box on a helicopter structure, such as its fuselage. The oblique bars are distributed around the main gear box and inclined relative to the rotor axis so as to converge with one another substantially at top ends towards a point on the rotor axis, the oblique bars being articulated and joined on the one hand to the main gear box by means of the top ends and on the other hand to the fuselage by bottom ends and by means of rigid levers, a same number of said levers being provided as there are oblique bars. Each lever supports at least one oscillating weight at one end and is articulated and joined to the fuselage by an opposite end part, in the vicinity of which the bottom end of a corresponding oblique bar is articulated on the corresponding lever. The articulated joints link each lever to the fuselage and to the corresponding oblique bar and are realized as articulated joints which pivot at least about pivot axes substantially perpendicular to a corresponding radial plane containing the rotor axis and a longitudinal axis of the corresponding oblique bar. Each lever is also linked to the main gear box by at least one torsion spring that is biased about a torsion axis that is substantially perpendicular to the corresponding radial plane, i.e. substantially parallel with the pivot axis of each lever on the fuselage and on the corresponding oblique bar.

The document U.S. Pat. No. 6,247,684 describes an antivibration device for reducing the transmission of vibration between two bodies. An elastic annular element is connected to the two bodies and is deformed under the action of vibration generated in said bodies. A resonator is connected, via two bending flexible leaves, to the internal face of the annular element. A support is arranged inside the elastic annular element. The support is secured, on the one hand to the bending flexible leaves and, on the other hand, to support pieces each bearing a mass. The document EP2628682 describes a device for dynamic isolation and damping of dynamic vibrations, in a passive way. The device is for a space shuttle and isolates and dampens payload. A plurality of identical elementary unit elements allows the device to be modular through individual modularity of each of the elementary unit elements that is tailored and designed individually. Each of the elementary unit element comprises a spring component and a damping component. The space shuttle and the payload are each secured to the deformable middle of spring components. At their outer ends, series of spring components are attached together and to series of parallel damping components.

The document EP1469224 describes an active spring-damper mechanism. The active spring-damper mechanism has a supporting spring member in the form of a flexible leaf spring that is fixed to a vibration-rigid structure. At the top of the free end of this supporting flexible leaf spring, a fastening element is arranged to be supported through an elastomer body on the flexible leaf spring. An annular space is formed by two leaf springs which are mutually conjugated and joined together.

The document WO2014195575 describes a tuned mass damper arrangement having an auxiliary mass which is attached to a vibrating structure via a wire rope isolator. A mass damper is provided with an additional intermediate block between attachment blocks. The attachment blocks are joined by a large helical spring wire, whereas the intermediate block is coupled to the attachment blocks via nested small helical spring wires, respectively.

The document U.S. Pat. No. 4,673,170 a dynamic recoil damping mechanism having a central coil compression spring means as a helical coil. Four articulated arms are each articulated for allowing a pivoting elbow-like action.

The document U.S. Pat. No. 5,228,640 describes a device for the elastic coupling between two parts, especially the principal transmission box and the fuselage of an aircraft with rotating wings, such as a helicopter. This device includes first and second inner and outer tubular bodies, and an elastic connection, housed in an annular space existing between the first and second bodies and coupling the first and second bodies in a leak tight fashion. The annular space is separated by the elastic connection into first and second chambers filled with a liquid. These first and second chambers are in communication with the inside of the first body. On the inside of this first body, there is a liquid distributor provided with an elastic damping connection and including two pistons, which are coupled by a piston rod and separated from each other by a distance separating orifices in the first and second chambers.

The document U.S. Pat. No. 4,458,861 describes an anti-vibration suspension device for a main transmission box of a helicopter. This anti-vibration suspension device comprises two elongated, flexible, elastic bars which are arranged parallel to each other and to the longitudinal axis of the helicopter's fuselage, at opposite sides of the transmission box. Each one of said bars is pivotally connected at two points to the helicopter's fuselage and has swinging bodies at its extremities. The bars, the pivotal connections and the swinging bodies are symmetrically arranged with respect to both the longitudinal and the transverse planes through a rotor shaft of the helicopter. Furthermore, means that are rigidly connecting the base of the main transmission box with each elastic bar in a region intermediate the pivotal connections between the bar and the helicopter's fuselage are provided, whereby each bar is made rigid in the intermediate region and has flexible portions between that region and the pivotal connections to the helicopter's fuselage. Moreover, a rod is provided that extends substantially in line with the helicopter's rotor shaft and is connected at its opposite ends with the base of the main transmission box and the helicopter's fuselage, the main transmission box being suspended through essentially only the bars and the rod and the latter serving to relieve the bars of the lifting forces imposed on the main transmission box.

The document U.S. Pat. No. 5,947,453 describes a spring-mass vibration absorber for absorbing vibration in a structure. This spring-mass vibration absorber comprises a baseplate with a first surface and a second surface, and a plurality of recurved springs connecting the baseplate to the structure. Each one of the recurved springs is fixedly connected to the first surface of the baseplate at a baseplate connection point, and fixedly connected to the structure at a structure connection point.

However, all of the above-described systems are comparatively complicated and bulky. Furthermore, they have complex designs and mainly use heavy and expensive components that are comparatively demanding on manufacturing tolerances. Consequently, they are rather expensive and time-consuming in manufacturing.

BRIEF SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a new vibration isolating device that is adapted for an elastic coupling of a first component to a second component and for vibration isolation in predetermined frequency ranges between said first and second components, said vibration isolating device being comparatively light-weight and inexpensive and having a simple design and an increased life time compared to conventional vibration isolating devices.

This object is solved by a vibration isolating device with the features of claim1. More specifically, according to the present invention a vibration isolating device that is adapted for an elastic coupling of a first component to a second component and for vibration isolation in predetermined frequency ranges between the first and second components comprises at least a first and a second elastically deformable plate that are attached to each other in at least two separate connecting points. The first elastically deformable plate comprises a first curvature located in a region between the at least two separate connecting points and the second elastically deformable plate comprises a second curvature located in a region between the at least two separate connecting points. The first and second curvatures are arranged such that a gap is defined between the first and second elastically deformable plates in the regions between the at least two separate connecting points, wherein the first and second curvatures are adapted to be reduced in operation if a tension force that moves the at least two separate connecting points away from each other is applied to the vibration isolating device, and wherein the first and second curvatures are adapted to be increased in operation if a compression force that moves the at least two separate connecting points towards each other is applied to the vibration isolating device.

Advantageously, the vibration isolating device according to the present invention has a comparatively simple design with a reduced amount of bearings and is comparatively low-cost, as e.g. no expensive components, such as hydraulics and so on, are required for its implementation. In particular, instead of mechanical bearings elastic parts can be used, thus, leading to comparatively low wear. Furthermore, it is less demanding on manufacturing tolerances than comparative conventional vibration isolating devices, while providing a higher overall life time and allowing for reduced maintenance efforts. Moreover, the vibration isolating device according to the present invention provides for comparatively high fatigue strength, if the first and second elastically deformable plates are embodied by means of properly applied composite materials, in particular carbon composites. Finally, it can be built more compact and slender than conventional vibration isolating devices and, consequently, be used to replace e.g. existing connection struts in existing vibration isolating arrangements without need for any additional devices.

According to one aspect of the present invention, the vibration isolating device is adapted for connecting two subsystems, such as e.g. a main gear box and a fuselage of a helicopter. The vibration isolating device according to the present invention primarily comprises two or more elastic plates, which are preferentially bar- or lath-shaped and connected to each other at their respective ends. Preferred materials for these elastic plates are carbon composites, but other composites and metals are also applicable.

Preferably, the elastic plates are not straight, but have a curvature. Thus, when a tension force is applied to the vibration isolating device according to the present invention, the elastic plates are straightened, i.e. their curvature is reduced. When a compression force is applied thereto, however, the curvature of the elastic plates increases. The tension and compression forces, therefore, lead to changes Δa of a predetermined length a between the respective ends of the vibration isolating device.

The decreased (tension) or increased (compression) curvature of the elastic plates preferably leads to lateral displacements Δbi at locations i along the elastic plates and other parts that are attached to the elastic plates. When the curvature is comparatively small, a ratio xi between the lateral displacements Δbi at certain locations and the length changes Δa can be comparatively large. In order to achieve a required efficient vibration isolation, preferentially corresponding vibration isolation masses Mi are placed at locations i where xi is large, wherein usually a maximum ratio xi is reached in the middle between the respective ends of the elastic plates. Realistic values for xi in such a configuration with two elastic plates are comprised in an interval from 2 to 20.

According to one aspect of the present invention, levers can be attached to the elastic plates in order to further amplify the lateral displacements Δbi at locations i on the levers. Usually, a maximum lateral displacement Δbi occurs at respective free ends of the levers, thereby increasing the ratio xi. Realistic values for xi in such a configuration with two elastic plates and corresponding levers are comprised in an interval from 2 to 50. The lateral displacements Δbi can even further be amplified by placing a third elastic plate between two locations i on the two other elastic plates, preferably instead of the corresponding levers.

Preferably, an underlying isolation frequency of the vibration isolating device according to the present invention is tuned with the corresponding vibration isolation masses Mi, the ratios xi and the stiffness of the applied elastic plates and the stiffness of springs Ki that can be arranged between locations i on the elastic plates. More specifically, increasing the stiffness of the elastic plates and/or the springs leads to a higher isolation frequency, while increasing the corresponding vibration isolation masses Mi or increasing the ratios xi at the corresponding vibration isolation masses Mi leads to a lower isolation frequency.

According to a preferred embodiment of the present invention, at least one of the first and second elastically deformable plates comprises composite material and/or metal.

According to a further preferred embodiment of the present invention, the composite material comprises a carbon fiber-reinforced polymer.

According to a further preferred embodiment of the present invention, at least one of the first and second elastically deformable plates comprises an associated vibration isolation mass.

According to a further preferred embodiment of the present invention, the associated vibration isolation mass is arranged in the region of the first and/or second curvature of the at least one of the first and second elastically deformable plates.

According to a further preferred embodiment of the present invention, the associated vibration isolation mass is arranged in a region of the at least one of the first and second elastically deformable plates that exhibits a maximum ratio between a bulging distance and a length decrease of the vibration isolating device that occurs in operation in response to an increase of the first and second curvatures during application of a compression force.

According to a further preferred embodiment of the present invention, at least one of the first and second elastically deformable plates comprises an associated lever that is mounted to the at least one of the first and second elastically deformable plates in the region of the first and/or second curvature of the at least one of the first and second elastically deformable plates.

According to a further preferred embodiment of the present invention, the associated vibration isolation mass is arranged on the associated lever in a region that exhibits a maximum ratio between a lever opening distance and a length decrease of the vibration isolating device that occurs in operation in response to an increase of the first and second curvatures during application of a compression force.

According to a further preferred embodiment of the present invention, the first elastically deformable plate comprises at least one first associated lever and the second elastically deformable plate comprises at least one second associated lever.

According to a further preferred embodiment of the present invention, the first and second associated levers are interconnected by means of at least one spring element.

According to a further preferred embodiment of the present invention, the spring element is one of a helical spring, an elastically deformable connecting plate, a diagonally arranged flat spring, a Belleville spring, a disk spring and a coned-disk spring with a connecting rod.

According to a further preferred embodiment of the present invention, the at least one spring element is arranged in a region of the first and second associated levers that exhibits a maximum ratio between a lever opening distance and a length decrease of the vibration isolating device that occurs in operation in response to an increase of the first and second curvatures during application of a compression force.

According to a further preferred embodiment of the present invention, the first and second elastically deformable plates are interconnected by means of at least one spring element.

According to a further preferred embodiment of the present invention, the spring element is one of a helical spring, an elastically deformable connecting plate, a diagonally arranged flat spring, a Belleville spring, a disk spring and a coned-disk spring with a connecting rod.

According to a further preferred embodiment of the present invention, the at least one spring element is arranged in a region of the at least one of the first and second elastically deformable plates that exhibits a maximum ratio between a bulging distance and a length decrease of the vibration isolating device that occurs in operation in response to an increase of the first and second curvatures during application of a compression force.

According to a further preferred embodiment of the present invention, the first component is a main gearbox of a helicopter and the second component is a fuselage of the helicopter.

The present invention further provides a helicopter with a first component that is elastically coupled to a second component by means of a vibration isolating device that is embodied as described above.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a vibration isolating device1according to the present invention in unloaded state, which is preferably adapted for an elastic coupling of a first component4to a second component5and for vibration isolation in predetermined frequency ranges between these first and second components4,5. By way of example, the first component4can be a main gearbox (27ainFIG. 18) of a helicopter (27inFIG. 18) and the second component5can be a fuselage (27binFIG. 18) of this helicopter (27inFIG. 18). However, it should be noted that the vibration isolating device1is not limited to use in helicopters, but can instead be used in any rotary wing aircraft and in aerospace engineering in general, as well as in other technical domains, such as automotive engineering or machinery, where vibration isolation is required.

According to one aspect of the present invention, the vibration isolating device1comprises at least a first and a second elastically deformable plate that are attached to each other in at least two separate connecting points. Each one of these elastically deformable plates preferentially comprises a bar- or lath-shaped form with an overall length that is greater than its width. By way of example and for purposes of simplicity and clarity of the drawings, only two elastically deformable plates1a,1band only two separate connecting points2a,2bare shown.

In other words, the present invention is described by way of example with respect to a simplified illustrative configuration that comprises only two elastically deformable plates1a,1band only two separate connecting points2a,2b. However, it should be noted that this is not intended for restricting the present invention to such a simplified illustrative configuration.

Preferably, at least one of the two elastically deformable plates1a,1bcomprises composite material and/or metal. The composite material may comprise a carbon fiber-reinforced polymer.

According to one aspect of the present invention, the two elastically deformable plates1a,1bare attached to each other in the two separate connecting points2a,2bfor respectively defining associated bearing parts3a,3b. The latter are preferentially adapted for mounting to the two components4,5, respectively.

Preferably, each one of the elastically deformable plates comprises an associated curvature in its axial direction, i.e. its longitudinal extension, which is located between the separate connecting points. Illustratively, the elastically deformable plate1acomprises a first curvature2cand the elastically deformable plate1bcomprises a second curvature2d, both curvatures2c,2dbeing located in a region between the two separate connecting points2a,2b.

The two curvatures2c,2dare preferably arranged such that a gap2eis defined between the two elastically deformable plates1a,1bin the region between the two separate connecting points2a,2b. This gap2eis defined such that the vibration isolating device1comprises in the unloaded state an underlying length1kbetween the two components4,5that is smaller than the overall length of each one of the elastically deformable plates1a,1b. Consequently, the vibration isolating device1comprises in the unloaded state an underlying width1lthat is greater than it would be if the two elastically deformable plates1a,1bwould touch each other over their entire lengths.

According to one aspect of the present invention, the two curvatures2c,2dare adapted to be increased in operation if a compression force6that moves the two separate connecting points2a,2btowards each other is applied to the vibration isolating device1. They are preferably further adapted to be reduced in operation if a tension force7that moves the two separate connecting points2a,2baway from each other is applied to the vibration isolating device1.

More specifically, if the compression force6is applied to the vibration isolating device1such that the two curvatures2c,2dare increased, the vibration isolating device1is bulged out. In other words, the two elastically deformable plates1a,1bare forced into a bulged state as illustrated with dashed lines9a,9b. Consequently, the underlying length1kof the vibration isolating device1is decreased by a length change Δa1, as illustrated with an arrow6a, and its underlying width1lis increased by a lateral displacement Δb1, as illustrated with an arrow6b. If in contrast thereto the tension force7is applied to the vibration isolating device1such that the two curvatures2c,2dare decreased, the vibration isolating device1is flattened. In other words, the two elastically deformable plates1a,1bare forced into a stretched state as illustrated with dotted lines8a,8b. Consequently, the underlying length1kof the vibration isolating device1is increased by a length change Δa1, as illustrated with an arrow7a, and its underlying width1lis decreased by a lateral displacement Δb1, as illustrated with an arrow7b. As mentioned above, a ratio x1between the lateral displacement Δb1and the length change Δa1can be obtained that lies in a range from 2<x1<20.

According to one aspect of the present invention, at least one of the two elastically deformable plates1a,1bis provided with an associated vibration isolation mass. Illustratively, each elastically deformable plate1a,1bcomprises an associated vibration isolation mass1c,1d, respectively. Each associated vibration isolation mass1c,1dis preferably arranged in the region of the corresponding curvature2c,2dof the respective elastically deformable plate1a,1b. By way of example, the vibration isolation mass1cis arranged in the region of the curvature2cand the vibration isolation mass1dis arranged in the region of the curvature2d.

More preferably, each associated vibration isolation mass1c,1dis arranged in a region of the respective elastically deformable plate1a,1bthat exhibits the maximum ratio x1of the vibration isolating device1and that preferentially occurs in operation in response to an increase of the two curvatures2c,2dduring application of the compression force6. This maximum ratio x1can be determined between the lateral displacement Δb1in direction of the arrow6b, which is also referred to hereinafter as the “bulging distance”, and the length change Δa1in direction of the arrow6a, which is also referred to hereinafter as the “length decrease”. Accordingly, in the illustrated example the vibration isolation masses1c,1dare arranged approximately in the middle of the vibration isolating device1, seen in direction of its underlying length1k, where the maximum ratio x1occurs in operation.

FIG. 2shows the vibration isolating device1ofFIG. 1, wherein according to one aspect of the present invention now at least one spring element is provided for interconnecting the two elastically deformable plates1a,1b. By way of example, the two elastically deformable plates1a,1bare interconnected by means of two spring elements10a,10b, which are preferably embodied as helical springs. However, other realizations are likewise contemplated, such as e.g. an elastically deformable connecting plate (e.g.21ainFIG. 11), a diagonally arranged flat spring, a Belleville spring, a disk spring or a coned-disk spring with a connecting rod, and so on.

According to one aspect of the present invention, the two spring elements10a,10bare arranged in the region of the respective elastically deformable plate1a,1bthat exhibits the maximum ratio x1of the vibration isolating device1and that preferentially occurs in operation as explained above with reference toFIG. 1. More specifically, as this maximum ratio x1occurs at the location of the vibration isolation masses1c,1das explained above with reference toFIG. 1, the two spring elements10a,10bare preferably respectively attached to the two vibration isolation masses1c,1dfor interconnecting the two elastically deformable plates1a,1b.

FIGS. 3A-3Cshow an exemplary realization of the vibration isolating device1according toFIG. 2. More specifically,FIG. 3Ashows the vibration isolating device1in front view,FIG. 3Bin sectional view andFIG. 3Cin top view to further illustrate the above-described bar- or lath-shaped configuration of the two elastically deformable plates1a,1b. In this exemplary realization, the bearing parts3a,3bof the vibration isolating device1are illustratively embodied as bearing laminates with mounting openings11a,11b, which are adapted for mounting of the vibration isolating device1to the two components4,5ofFIG. 2.

According to one aspect of the present invention, the two elastically deformable plates1a,1bare rigidly attached to associated mounting flanges12a,12b, respectively, which preferably essentially define the vibration isolation masses1c,1dofFIG. 2. The rigid attachment is exemplarily performed by means of suitable fixation means13, such as screws or bolts, at lateral extensions14of the two elastically deformable plates1a,1b, preferentially via associated blocking plates15a,15b, respectively.

As the associated mounting flanges12a,12bpreferably essentially define the vibration isolation masses1c,1dofFIG. 2, they are interconnected according toFIG. 2by means of the two spring elements10a,10b. The latter are illustratively embodied as diagonally arranged flat springs in the form of thin curved plates, as best seen from part (C). Preferably, these diagonally arranged flat springs are also rigidly attached to the associated mounting flanges12a,12bby means of suitable fixation means13, such as screws or bolts.

According to one aspect of the present invention, the diagonally arranged flat springs exhibit a progressive stiffness, which preferentially increases during extension. Furthermore, the diagonally arranged flat springs preferably function as limits stops whenever the vibration isolating device1is subject to comparatively large compression forces in operation, i.e. when the compression force6ofFIG. 1exceeds a predetermined threshold.

FIG. 4shows the vibration isolating device1according toFIGS. 3A-3Cwith the two elastically deformable plates1a,1bthat define the bearing parts3a,3bwith the mounting openings11a,11b, respectively. However, in contrast toFIGS. 3A-3C, where the bearing parts3a,3bare implemented as bearing laminates, they are now implemented by means of plate loops16a,16b, respectively. Consequently, the two elastically deformable plates1a,1bnow preferably define a single integrated component.

FIG. 5shows the vibration isolating device1ofFIG. 1, wherein according to one aspect of the present invention now at least one of the two elastically deformable plates1a,1bcomprises an associated lever that is mounted to the at least one of the two elastically deformable plates1a,1bin the region of its curvature2c,2d. By way of example, each one of the two elastically deformable plates1a,1bis provided with a lever17a,17b, wherein the lever17ais mounted to the plate1aat its curvature2c, while the lever17bis mounted to the plate1bat its curvature2d. The levers17a,17bcan be implemented as integral parts of the two elastically deformable plates1a,1b, respectively, or as separate components.

It should be noted that the curvatures2c,2dare slightly modified with respect toFIG. 1in order to allow for a sufficient length of the levers17a,17b. More specifically, inFIG. 1the curvatures2c,2dare provided such that the gap2eofFIG. 1is maximal at least approximately in the middle of the vibration isolating device1, seen in direction of its underlying length1kofFIG. 1. In contrast thereto, the gap2eis now maximal in unloaded state of the vibration isolating device1at a location that is comparatively close to the component5and the levers17a,17bare connected to the two elastically deformable plates1a,1bat this location and have, consequently, free ends that point towards the component4. However, it should be noted that this configuration could likewise be mirrored so that the free ends of the levers17a,17bwould point towards the component5.

In operation of the vibration isolating device1, if the compression force6ofFIG. 1is applied to the vibration isolating device1such that the two curvatures2c,2dare increased, the vibration isolating device1is bulged out and the levers17a,17bare moved outwardly. In other words, the two elastically deformable plates1a,1bare forced into a bulged state and consequently, the underlying length1kof the vibration isolating device1as illustrated inFIG. 1is decreased by a length change Δa5, as illustrated with the arrow6aofFIG. 1, its underlying width1las illustrated inFIG. 1is increased by a lateral displacement Δb5p, as illustrated with the arrow6bofFIG. 1, and the levers17a,17bperform an outwardly directed lateral displacement Δb5l, as illustrated with the arrows18a. If in contrast thereto the tension force7ofFIG. 1is applied to the vibration isolating device1such that the two curvatures2c,2dare decreased, the vibration isolating device1is flattened and the levers17a,17bare moved inwardly. In other words, the two elastically deformable plates1a,1bare forced into a stretched state and, consequently, the underlying length1kof the vibration isolating device1as illustrated inFIG. 1is increased by a length change Δa5, as illustrated with the arrow7aofFIG. 1, its underlying width1las illustrated inFIG. 1is decreased by a lateral displacement Δb5p, as illustrated with the arrow7bofFIG. 1, and the levers17a,17bperform an inwardly directed lateral displacement Δb5l, as illustrated with the arrows18b.

As mentioned above with reference toFIG. 1, a ratio x5pthat can be obtained with respect to the two elastically deformable plates1a,1bbetween the lateral displacement Δb5pand the length change Δa5lies in a range from 2<x5p<20. However, a ratio x5lthat can be obtained with respect to the two levers17a,17bbetween the lateral displacement Δb5land the length change Δa5preferably lies in a range from 2<x5l<50. In other words, the two levers17a,17bamplify the lateral displacements Δb so that Δb5l>Δb5p.

According to one aspect of the present invention, at least one and, preferentially, each one of the levers17a,17bis provided with an associated vibration isolation mass. By way of example, the lever17ais provided with the vibration isolation mass1cofFIG. 1and the lever17bis provided with the vibration isolation mass1dofFIG. 1. Preferably, each associated vibration isolation mass is arranged on the corresponding lever in a region that exhibits a maximum ratio x5lbetween the lateral displacement Δb5lof this lever in direction of the arrow18a, which is also referred to hereinafter as the “lever opening distance”, and the length change Δa5in direction of the arrow6a, which is also referred to hereinafter as the “length decrease” of the vibration isolating device1and that occurs in operation in response to an increase of the curvatures2c,2dduring application of the compression force6ofFIG. 1. Accordingly, in the illustrated example the vibration isolation masses1c,1dare arranged at the free ends of the levers17a,17b, respectively, where the maximum ratio x5loccurs in operation.

FIG. 6shows the vibration isolating device1ofFIG. 5, wherein according to one aspect of the present invention now at least one spring element is provided for interconnecting the two levers17a,17b. By way of example, the two levers17a,17bare interconnected by means of a spring element10d, which is preferably embodied as a helical spring. However, as already mentioned above, other realizations are likewise contemplated, such as e.g. an elastically deformable connecting plate (e.g.21ainFIG. 11), a diagonally arranged flat spring, a Belleville spring, a disk spring or a coned-disk spring with a connecting rod, and so on.

According to one aspect of the present invention, the spring element10dis arranged in the region of the respective lever17a,17bthat exhibits the maximum ratio x5lof the vibration isolating device1and that preferentially occurs in operation as explained above with reference toFIG. 5. More specifically, as this maximum ratio x5loccurs at the location of the vibration isolation masses1c,1das explained above with reference toFIG. 5, the spring element10dis preferably respectively attached to the two vibration isolation masses1c,1dfor interconnecting the two levers17a,17b.

FIG. 6further illustrates that the levers17a,17bcan be provided in an application-specific manner with additional vibration isolation masses and that they can be interconnected by additional spring elements, and that optionally also the two elastically deformable plates1a,1bcan be provided with vibration isolation masses and interconnecting spring elements. By way of example, the levers17a,17bare provided with additional vibration isolation masses1e,1h, respectively, which are interconnected by means of an additional spring element10c. Furthermore, the two elastically deformable plates1a,1bare illustratively provided with optional vibration isolation masses1f,1gand1h,1j, respectively, wherein the vibration isolation masses1f,1iare exemplarily interconnected by means of the spring element10aofFIG. 2and wherein the vibration isolation masses1g,1jare exemplarily interconnected by means of a spring element10b, which can be embodied in the same manner as the spring element10a.

FIG. 7shows the vibration isolating device1ofFIG. 5, which according to one aspect of the present invention now comprises two levers19a,19b. In contrast to the levers17a,17bofFIG. 5, the two levers19a,19bare kinked outwardly.

However, it should be noted that this configuration is dependent on space that is available in an associated operating environment for an installation of this vibration isolating device1. In other words, the kinks may be directed in other directions or just be implemented smoother than illustrated.

FIG. 8shows the vibration isolating device1ofFIG. 5with the two levers17a,17b, which are provided with the associated vibration isolation masses1c,1d, respectively. However, in contrast toFIG. 5the two vibration isolation masses1c,1dare now interconnected by means of the spring elements10a,10bofFIG. 6.

FIG. 9shows an exemplary realization of the vibration isolating device1with the two elastically deformable plates1a,1band the two levers17a,17baccording toFIG. 5to further illustrate a preferred bar- or lath-shaped configuration of these two levers17a,17band the two elastically deformable plates1a,1b. In this exemplary realization, the bearing parts3a,3bof the vibration isolating device1are illustratively embodied as bearing laminates with the mounting openings11a,11bofFIGS. 3A-3B, which are adapted for mounting of the vibration isolating device1to the two components4,5ofFIG. 5.

According to one aspect of the present invention, the two levers17a,17bare separate components that are rigidly attached to the two elastically deformable plates1a,1bat associated connection sections20a,20b, respectively, which are arranged in the regions of the curvatures2c,2d. The rigid attachment is exemplarily performed by means of the suitable fixation means13ofFIG. 3C, such as screws or bolts.

Preferably, the two levers17a,17bare connected with the vibration isolation masses1c,1d, respectively, which are preferentially rigidly attached to the two levers17a,17b. This rigid attachment is exemplarily also performed by means of the suitable fixation means13, such as screws or bolts.

FIGS. 10A and 10Bshown an exemplary realization of the vibration isolating device1with the two elastically deformable plates1a,1band the two levers17a,17baccording toFIG. 8, as well as with two additional levers17c,17d. More specifically,FIG. 10Ashows the vibration isolating device1in front view andFIG. 10Bin sectional view to further illustrate a preferred bar- or lath-shaped configuration of the four levers17a,17b,17c,17dand the two elastically deformable plates1a,1b. In this exemplary realization, the bearing parts3a,3bof the vibration isolating device1are again illustratively embodied as bearing laminates with the mounting openings11a,11bofFIGS. 3A-3B, which are adapted for mounting of the vibration isolating device1to the two components4,5ofFIG. 8.

The four levers17a,17b,17c,17dare illustratively arranged laterally with respect to the two elastically deformable plates1a,1band formed as integral parts thereof. Thus, the lever17bis hidden inFIG. 10Aby the lever17cand the lever17dis hidden inFIG. 10Aby the lever17a. Alternatively, the levers17a,17cand17b,17dcould respectively be combined to single levers according toFIG. 9, for instance.

According to one aspect of the present invention, the levers17a,17cand the levers17b,17dare respectively rigidly attached to each other at their free ends via the mounting flanges12a,12bofFIG. 3B. Furthermore, the levers17a,17dand the levers17b,17care respectively interconnected via the mounting flanges12a,12bby means of the spring elements10a,10b. However, as the rigid attachment of the mounting flanges12a,12band the spring elements10a,10bis at least similar to what is described above with reference toFIGS. 3A-3C, a more detailed description thereof is omitted here for brevity and conciseness.

FIG. 11shows the vibration isolating device1ofFIG. 1, wherein according to one aspect of the present invention now at least one spring element in the form of an elastically deformable connecting plate21ais provided for interconnecting the two elastically deformable plates1a,1b. By way of example, the two elastically deformable plates1a,1bare interconnected by means of this elastically deformable connecting plate21aat a location, where the gap2eofFIG. 1is maximal in unloaded state of the vibration isolating device1.

According to one aspect of the present invention, the two elastically deformable plates1a,1band the elastically deformable connecting plate21aare manufactured in one piece, i.e. as an integral component. Alternatively, the elastically deformable connecting plate21acan be a separate component that is rigidly attached to the elastically deformable plates1a,1b.

Preferably, the elastically deformable connecting plate21ais provided with the vibration isolation mass1cofFIG. 1. The latter is at least approximately arranged at a central position of the elastically deformable connecting plate21a, which corresponds to a position of a maximum ratio x11. This maximum ratio x11can be determined according to what is described above, so that a more detailed description of this determination can be omitted for brevity and conciseness.

According to one aspect of the present invention, while the elastically deformable plates1a,1bperform lateral displacements Δb1as described above with reference toFIG. 1, the elastically deformable connecting plate21ais adapted and arranged to perform longitudinal displacements Δb11, as illustrated with arrows22a,22b. The arrow22aexemplarily illustrates the longitudinal displacement Δb11that is performed by the elastically deformable connecting plate21aif the compression force6ofFIG. 1is applied to the vibration isolating device1, and the arrow22bexemplarily illustrates the longitudinal displacement Δb11that is performed by the elastically deformable connecting plate21aif the tension force7ofFIG. 1is applied to the vibration isolating device1. Preferably, these longitudinal displacements Δb11are greater than the lateral displacements Δb1according toFIG. 1, i.e. Δb11>Δb1.

FIG. 12shows the vibration isolating device1ofFIG. 5with the two elastically deformable plates1a,1band the two levers17a,17b. However, in contrast toFIG. 5the free ends of the levers17a,17bare no more provided with the vibration isolation masses1c,1dofFIG. 5, but are instead interconnected by means of an elastically deformable connecting plate21b. The latter is provided with the vibration isolation mass1c, similar to the elastically deformable connecting plate21aofFIG. 11.

According to one aspect of the present invention, the two levers17a,17band the elastically deformable connecting plate21bare manufactured in one piece, i.e. as an integral component. Alternatively, the elastically deformable connecting plate21bcan be a separate component that is rigidly attached to the free ends of the two levers17a,17b.

FIG. 13shows the vibration isolating device1ofFIG. 2with the two elastically deformable plates1a,1band the two vibration isolation masses1c,1d, which are interconnected by means of the spring element10aofFIG. 2. However, in contrast toFIG. 2the curvatures2c,2dof the two elastically deformable plates1a,1bare now such that the vibration isolating device1illustratively exhibits a bi-concave shape in cross section, instead of a bi-convex shape as illustrated inFIG. 2. Such a shaping provides advantageous limit stops if comparatively high compression forces are applied to the vibration isolating device1.

FIG. 14shows the vibration isolating device1ofFIG. 5with the two elastically deformable plates1a,1band the two levers17a,17b. According to one aspect of the present invention, the two levers17a,17bare provided with the vibration isolation masses1c,1eand1d,1gofFIG. 6, respectively, and only the elastically deformable plate1ais provided with the vibration isolation mass1f. However, these vibration isolation masses1c,1e,1d,1gand1fare not arranged symmetrically on the two levers17a,17band the elastically deformable plate1a.

Furthermore, the vibration isolating device1can be provided with spring elements that are also not necessarily arranged symmetrically on the vibration isolating device1and that may arbitrarily connect selected components. For instance, the spring element10aofFIG. 6connects the two elastically deformable plates1a,1bmerely at associated plate-spring connecting points1m,1nand is illustratively arranged obliquely within the vibration isolating device1. Furthermore, the spring element10bofFIG. 6connects the lever17ato the elastically deformable plate1aindependent on any associated vibration isolation masses. Finally, the spring element10cofFIG. 6connects the lever17bto the elastically deformable plate1bfrom the vibration isolation mass1fthat is associated with the elastically deformable plate1bto a lever-spring connecting point17ethat is provided independent on any associated vibration isolation masses on the lever17b.

FIG. 15shows an exemplary realization of the vibration isolating device1according toFIG. 13for further illustrating its bi-concave shape in cross section. However, as the vibration isolating device1ofFIG. 15is otherwise similar to the one ofFIG. 4, a more detailed description thereof is omitted for brevity and conciseness.

FIG. 16shows a first arrangement that is suitable for adjusting the weight, i.e. center of gravity1p, of an adjustable vibration isolation mass1othat is illustratively associated with the elastically deformable plate1aofFIG. 1. According to one aspect of the present invention, the weight adjustment is achieved by a translational movement of the center of gravity1pof the adjustable vibration isolation mass1o, as indicated with an arrow24. Such a translational movement can e.g. be imposed on the adjustable vibration isolation mass1oby means of a correspondingly configured drive unit23in the form of a linear drive. However, such a drive unit is well-known to the person skilled in the art and, therefore, not described in further detail for brevity and conciseness.

FIG. 17shows a second arrangement that is suitable for adjusting the weight, i.e. center of gravity1p, of the adjustable vibration isolation mass1oofFIG. 16that is illustratively associated with the elastically deformable plate1aofFIG. 1. According to one aspect of the present invention, the weight adjustment is now achieved in contrast toFIG. 16by a rotational movement of the center of gravity1pof the adjustable vibration isolation mass1o, as indicated with an arrow25. Such a rotational movement can e.g. be imposed on the adjustable vibration isolation mass1oby means of the correspondingly configured drive unit23ofFIG. 16in the form of a rotational drive with an eccentric center of gravity.

FIG. 18shows a vibration isolated arrangement26for illustrating an exemplary application environment of at least one vibration isolating device1as described above with respect to any one of the preceding figures. More specifically, according toFIG. 18, at least one vibration isolating device1is used to connect a main gear box27aof a helicopter27to a fuselage27bof the helicopter. Illustratively, two vibration isolating devices1are used and, preferably, three or more such vibration isolating devices1are used.

By way of example, each vibration isolating device1is rigidly attached to a component joint4aprovided at the main gear box27avia its bearing part3a, e.g. by means of screws or bolts. Furthermore, each vibration isolating device1is rigidly attached to a component joint5aprovided at the fuselage27bvia its bearing part3b, e.g. by means of screws or bolts. Thus, vibration isolation can be achieved between the main gear box27aand the fuselage27b.

It should be noted that the above described, preferred embodiments are merely described to illustrate possible embodiments of the present invention, but not in order to restrict the present invention thereto. Instead, multiple modifications and variations of the invention are possible and should, therefore, also be considered as being part of the invention. For instance, while inFIG. 16andFIG. 17adjustable vibration isolation masses are illustrated; also the spring elements described above can be adjustable. By way of example, correspondingly configured drive units can be used for changing a respective pre-tension and/or correspondingly provided free end lengths thereof, and so on.