Flat drive with foliated structure, flat drive device and lifting plane of aircraft

FIELD: electricity.

SUBSTANCE: invention is related to piezoelectric instruments for control of aircraft lifting planes. Flat drive with foliated structure that is symmetrical in relation to middle plane includes flat piezoelectric layer, which has active direction and is connected with one flat passive layer of cloth with rigid haircloth and weft that are oriented in accordance with two directions that form network of cells. Both directions of every cloth layer are same. Active direction of every piezoelectric layer is oriented along single diagonal of cloth layers cells. Flat drive device consists of two drives installed top to tail. Lifting plane of aircraft, for instance, helicopter blade, includes top and bottom surfaces, and also drive device close to back edge.

EFFECT: increase of aircraft dirigibility.

7 cl, 9 dwg, 2 tbl, 6 ex

The present invention relates to an active drive mechanism capable of transverse shear displacement in the plane of the device to use two drives of this type and its application to the curvature of the structure.

The invention concerns, in particular, flat active drive with a layered structure that includes at least one planar piezoelectric layer having active control, applied and combined with at least one passive flat layer of fabric with a rigid warp and the weft, forming a grid of cells. Active management of the piezoelectric layer is oriented in a particular way relative to the grid cell layers of fabric.

The invention is applicable to the active curvature of such structures as, for example, the blades of the helicopter.

In Aeronautics the need to improve the manageability, security, or reduce audio interference forces developers aircraft more and more often to use the active elements of the bend. These elements can deform in a controlled manner in response to a specific command in order to change the behavior of aircraft in their environment.

Thus, the controlled bending of the bearing planes of aircraft has been the subject of numerous studies and has led to the development of p is ibodov, allowing a shift of the upper surface of the wing (or extrados) relative to its bottom surface (or intrados).

In addition to mechanical and hydraulic actuators, such as De Laurier and others (USA 5288039) or Young and others (USA 6173924), you can enumerate also the piezoelectric actuators, which are of the greatest interest, such as described Jeffs and others (GB 2348537) or Matthew L. Wilbur and others ("Hover testing of the NASA/ARMY/MIT active twist rotor prototype blade; the American Helicopter Society 56^thAnnual Forum, Virginia Beach, Virginia, May 2-4, 2000) or in the French patent on the name of the applicant (FR 2833571).

In British patent GB-2348537 rear edges of the upper and lower surfaces of the wing are connected by the tube, cut parallel to the rear edge, following the wingspan. Both cut edges adapted for placement of piezoelectric actuators, which are made with the possibility of moving edges relative to each other along the wing span. Given the small size of the available elongation, relative movement of the rear edges too weak to provide effective controlled curvature of the bearing surface.

In the works of Matthew L. Wilbur blade rotor helicopter equipped with six locations distributed along its scope and in the zone of maximum quasilocal thickness, the two piezoelectric actuators, one on top the second side, the other on the bottom. Each actuator includes two piezoelectric layer type MFC (Macro Fiber Composite)that can increase or decrease along the active direction. The first Central layer of glass is located between the two piezoelectric layers, forming a three-layer or sandwich structure. The active direction of the piezoelectric layers are oriented respectively along the warp and weft of the glass fabric. This is the first sandwich structure, in turn, is enclosed with the formation of the other in a sandwich structure between the other two layers of glass fabric in which the warp and the weft are oriented diagonally to the canvas and duck fabrics Central layer and, consequently, to the active areas. This five-layer sandwich structure and is the drive.

When quasiplastic actuator is activated, it is deformed, spontaneous coiling and inducyruya when this curvature directly blades. The fact that the set of actuators are located on the top side and bottom side, increases the curvature of the blade. In addition to the difficulties of embedding such aggregates in the structure of the blades, they are located in a closed compartment, called "D-spar"with high torsional stiffness, which has a strong resistance to deformation of the actuators, thus creating significant n the voltage between the individual layers. In addition, because these drives are located on the upper and on the lower sides of the maximum thickness of the profile, they also have strong voltage due to the fact that the blade is loaded on the pulsating bending.

In order to limit this resistance, in the French patent on the name of the applicant (FR 2833571) according to one of embodiments of the invention, the rear edges of the top and bottom sides are directly connected to the piezoelectric actuators to shift and continuously closing the incision along the span of the blade in order to obtain a high torsional stiffness. However, to maintain the rigidity you need to embed the drives directly near the rear edge, where the thickness of the plane is small, which limits the size of the actuator thickness profile. Given the small magnitude of the displacement angle achieved in this way, the relative offset of the rear edges too weak to provide effective controlled curvature of the plane.

Thus, the object of the invention is to develop a device that continuously closed the incision blades, provides high torsional stiffness, limited internal voltage when exposed to the blade external loads and allow a significant amount of progress between the two rear edges of the upper and the lower is her sides throughout its scope.

The object of the present invention is a planar actuator deformable in shear, and a device that uses two drive according to the invention, installed by Jack and is capable of shear deformation, each in his own plane. The invention also concerns the characteristics of the integration of such devices into the design of the blades of the helicopter, where it continuously overlaps the initially outdoor section.

The first object of the invention is a planar actuator with a layered structure having two zones of fixation intended for transmission generated by the relative movement of the shift, and at least three flat superimposed on each layer comprising at least one layer of fabric, the warp and the weft of which consist of a rigid fibers arranged according to two directions, forming cells lying adjacent parallelograms, and at least one flat active piezoelectric layer made with the ability to lengthen or shrink along the active direction, each side of one layer is bonded over its entire surface to one side of the adjacent layer, characterized in that the layered structure is symmetric, contributing flat shear strain; the active direction of each flat piezoelectric layer is oriented along the same diagonally opposite corners is whether the cells of each layer of tissue, the warp and the weft of which is oriented according to the same two directions; zone lock actuator having a shape that is elongated along the first direction, are located along opposite ends of the actuator according to the second direction, so that each flat layer of fabric loaded along the respective diagonals of the cells, the parallelograms are deformed, causing it to move in the plane of the zone of fixation parallel to each other, due to the first direction.

It is advisable that the layered structure was formed from one active layer interposed between two layers of tissue.

It is also advisable that the layered structure was formed from one layer of tissue located between the two active layers.

The invention also concerns a flat drive device consisting of two established a Jack actuators, two opposite zones of fixation are connected, and two active directions are not parallel, while the two other areas fixation of actuators configured to move along the first direction of the plane with an amplitude equal to the sum of the displacements of both single drives.

The invention also applies to the bearing plane of the aircraft, including the upper and lower surfaces, and a flat drive unit near the rear edge, when this flat is evadne device has two opposing zones commit which are connected respectively with the lower surface and upper surface.

Preferably, two opposing zones of fixation, interconnected, and the rear edge were located by following the chord, and on the other side of the two opposing areas of the commit.

It is preferable that two opposing interconnected zone of fixation and trailing edge were located by following the chord, on the same side of two opposite zones of fixation, and two opposing interconnected zones commit formed in the rear edge.

The invention is further explained in the description of variants of its implementation, with reference to the drawings figures, in which identical references indicate similar elements and in which:

Figure 1 depicts a schematic view of the actuator according to the invention at rest.

Figure 2 illustrates the shear deformation of the actuator 1, when it is activated.

Figure 3 represents a diagram of the shift characteristic of the actuator according to the invention.

4 is a schematic view corresponding device according to the invention at rest.

Figure 5 represents the shear deformation device 4 when it is activated.

6 is a view in isometric plot of the blades of the helicopter, which is embedded in the device according to the first variant implementation.

F. g illustrates the functioning of the device according to the first variant implementation.

Fig shows typical shear device embedded in the blade.

Fig.9 - section of the device in helicopter rotor blades according to the second variant of realization.

Example 1

Flat actuator with a layered structure And corresponding to the present invention and shown in figure 1, has a thickness t according to the Z-direction, the length L according to the X-direction and width W according to the direction Y. This drive consists of the following elements.

In the Central plane is a flat active piezoelectric layer 1, can lengthen or shrink along the bisector of the directions X and Y, when it is energized. This piezoelectric layer consists of unidirectional rectangular piezoelectric fibers oriented along the bisector of the directions X and Y, and fed by the voltage electrodes 1A and 1b. Fiber enclosed in a sandwich structure between structural epoxy layer and polyamide films, including finger electrodes, perpendicular to the fibers. The Assembly has a thickness of approximately 0.3 mm and a rectangular active area, for example, 85×57 mm². The lack of a layer of this type is that it is very thin and sensitive, therefore, to buckling. Another drawback concerns its extension along the X-direction, which can create problems in places with which leivadia zones commit to their bases, in particular, if the latter is very hard. The shear stress can cause in this case, the gap of adhesive bonding. Over the entire area above the flat active layer placed first fabric 2 with a thickness of 0.2 mm, for example, type taffeta fiber which is made of a material with high modulus, as, for example, carbon NM. In this fabric the warp and the weft are oriented respectively along the direction X and direction Y.

The warp and the weft of the fabric to define the network structure located next to each other parallelograms.

Bottom over the entire area above the flat active layer placed second fabric 3, is identical to the first fabric 2 and oriented in the same way.

Two adhesive connections 4 and 5 are located between the three layers to bind them together. These adhesive joints have a thickness that is adjusted to 0.1 mm by means of a flexible textile mesh, and the young's modulus, chosen in such a way as to convey as best as possible the movement of the shift of the aforementioned flat active piezoelectric layer 1 of the above tissues 2 and 3.

The fastening area S1 oriented, following weft thread fabrics, and extends along one end, following the warp threads of the same tissue. It is, for example, on one outer side of the drive.

Another area of fixation S2 oriented, following the UYa the warp fabrics, and extends along the other end, following the weft threads of these same tissues. It is, for example, on another outer side of the drive.

The principle of operation of the actuator is that when the flat active layer 1 is powered by the voltage across the electrodes 1A and 1b, it generates elongation along the bisector of the directions X and Y in the X-Y plane, which is due to adhesive joints is transmitted both composite fabrics 2 and 3. The parallelograms of cells, tissues, loaded along the same diagonal, deformed. This deformation is converted into a displacement angle γ with respect to the direction Y, as shown in figure 2, and the flat active layer 1 produces the movement of the shift X_γ=γ×W, following the X-axis, as indicated in figure 2 above.

The drive is slightly longer along the direction X, so as weft threads of the fabric events. Adhesive bonding while slightly loaded. Also the drive has a slight elongation along the direction Y, as this counteracts the base fabric. Drive weakly deformed in the Z-direction, since it is symmetric, and the resulting applied force is in the X-y plane.

This drive was manufactured using as a flat active layer MFC with an active section 85×57×0.3 mm³enclosed in a sandwich-structure is between two carbon fabrics SXM10, and has been tested for performance under stress ±750 C.

Through the outlet of the three sensors glued in the center of the flat active layer were measured:

deformation along the direction X;

deformation along the direction Y;

- shear γ.

By means of an optical sensor were also measured travel the four corners of the actuator, which is being attributed to its width W, allow the shear deformation. The results are presented in table 1, in which l μdef=10^-6the meter on.

Example 2

In the framework of the three-layer drive one of the options for its implementation can increase the movement of the shift.

This drive consists of the following elements.

In the centre is placed a fabric thickness of 0.2 mm, for example, the type of taffeta, fibers made from a material with high modulus, such as carbon NM. This is t the layer of fabric is flat and has the warp and the weft, oriented respectively along the direction X and direction Y. the warp and the weft to form a network of adjacent parallelograms.

Over the entire area of the above-mentioned layer of fabric placed first flat active piezoelectric layer, can increase or decrease along the bisector of the directions X and Y, when it is energized. This piezoelectric layer of the same type as mentioned in the previous example. It generates, thus, the angle of shift γ in relation to the x direction.

Bottom over the entire area of the above-mentioned layer of fabric placed second planar active piezoelectric layer, identical to the first and oriented the same way.

Two adhesive joints are located between the three layers to bind them together. These adhesive joints have a thickness that is adjusted to 0.1 mm by means of a flexible textile mesh, and the young's modulus, chosen in such a way as to convey as best as possible the movement of the shift of the aforementioned flat active piezoelectric layers of the above-mentioned composite fabric.

The first fastening area is on the outer side of the drive. It is oriented along the weft threads of the fabric and extends along one end, following the warp threads of the same fabric.

The second fastening area is on the other outer side of rivada. It is oriented along the weft threads of the fabric and extends along the other end, following the warp threads of the same fabric.

In working condition both flat active piezoelectric layer that drives simultaneously the same voltage. They provide the elongation along the same bisector of the directions X and Y in the X-Y plane, this elongation is transferred to a layer of tissue due to adhesive joints. The parallelograms of the tissue cells, loaded along the same diagonal, deformed. This deformation is converted in the shift γas in the previous example. Similarly, adhesive bonding loaded weakly, and the resulting force eld is in the X-y plane.

This drive is manufactured using carbon fabric SXM10, enclosed in a sandwich structure between the two MFC with an active section 85×57×0.3 mm³serving flat active piezoelectric layers, and has been tested in action the same measuring means and under the same conditions as in example 1.

The results are presented in table 2, in which l μdef=10^-6the meter on.

Figure 3 illustrates the performance evaluation of such a drive.

For naked MFC curve (I) is a direct shift angle γ, comb in the comb measured on MFC under voltage ±500 depending on the shearing forces F, the set based on the slope of the curve stiffness, calculated at the shift. If γ=0, the shear practically blocked, as it is that leads to the loss of just idling, which is γ max(320 μdef) for F=0.

For carbon fabric and two adhesive joints curve (II) is a direct, expressing a rigid shift of the whole Assembly.

Curve (III) shows the actuator, which is an Assembly of a tissue layer + adhesive with two MFC.

In addition to these two examples you can use more flat layers. Meanwhile, in order to comply with the invention, the structure implemented various options need to match both some of the main characteristics.

First, the structure must be symmetric with respect to the median plane in order to favor dps is tion of the shear deformation of the drive.

Further, the weft threads and warp threads of each of the flat layers of tissue that form the cells in the form of parallelograms, should all be oriented respectively along the same two lines in the plane parallel to the median plane.

In addition, all of the flat active piezoelectric layers must have, each in their own plane, the active direction, parallel and oriented in the same direction along the same diagonal cells in the form of a parallelogram.

Finally, the two zones of fixation must be on opposite ends of the weft or base layers of fabric and positioned respectively along the direction of the weft or base layers of fabric.

Example 3

The invention relates to a device comprising a Jack Assembly of the two actuators A1 and A2 are identical to the actuator As described in the previous examples. Both drives A1 and A2 are mounted as shown on figure 4, one above the other, parallel to each other and glued together by their respective zones commit S2.

The principle of the invention is such that when the first actuator similar to the actuator of example 1 or 2 is activated, it generates in the X-Y plane and at an angle of 45° elongation, which is tissue cell which is loaded along the first diagonal, are deformed into a parallelogram. This deformation is converted in the shiftγ and the first actuator produces movement of the shift X_γ1=γ×W, following the X-axis, as shown in figure 5.

Accordingly, upon activation of the second drive he provides in the X-Y plane and at an angle 135° elongation, which is transmitted into the tissue, cell, loaded along the second diagonal, are deformed into a parallelogram. This deformation is converted in the shift -γand a second actuator produces movement of the shift X_γ1=-γ×W, following the axis X. This movement of the shift is opposite to movement of the shift first actuator A1.

The value d is the total displacement of the shifting device between the respective zones of fixation S1 is equal to the sum of the values move the shift of each actuator, namely d=X_γ1-X_γ2and because the drives are identical, then d=2γ×W, as indicated in figure 5.

Example 4

The device according to the invention can use a combination of the two are not strictly identical drives. For example, it is possible to combine the first actuator, corresponding to example 1, with the second actuator having the same layered structure, but differing on the one hand, the fact that its width W along the Y-direction exceeds the width of the first actuator, and, on the other hand, the fact that both zones of fixation are located on the same side of this second drive.

The resulting device is in the case of two adjacent zones commit available with a single hand, which may be of practical interest for some applications.

The device according to the invention can be advantageously used in combination with the design of helicopter rotor blades in order to expose it to the curvature along the entire span. In these conditions, the system is no longer strictly flat in working condition, but slightly curved. However, this deformation is locally small and does not change the fundamental operation of the device described in the previous examples.

Example 5

As shown in figure 6, the device according to the invention can be placed inside the profile of the open bearing plane of the aircraft and near its rear edge. Carrier plane is called open because the top and bottom surfaces are not interconnected near the rear edge of this plane. The rear edges of the top surface and the bottom surface I is equipped with a reinforcing elements opposite zones of fixation S1 actuators A1 and A2 of the device. The rear edge glued or screwed on the level of the reinforcing elements to the areas of fixation S1 of each of the identical actuators A1 and A2. Glue or screw connections distributed along the span parallel to the axis X figure 5. Area S2 of the actuators A1 and A2 and the rear edge is located, following the chord, one and the other side is s from the fixing S1 actuators A1 and A2 of the device on a supporting plane. The plane of symmetry of the device in the quiescent state is located close to the plane of the chord of the profile and, thus, with zero bending axis. The device in this case is only a very weak stresses, when the blade is loaded in bending.

The device continuously overlaps a section of the supporting plane along its span. Meanwhile, can be carried out additional traction between the rear edges of the upper and lower surfaces by means of elastomer With a low modulus, glued to the reinforcing elements of each of the rear edges, and even directly between zones fixation S1 actuators A1 and A2 of the device, because the stiffness of the shear device causes the torsional stiffness of the bearing plane.

The principle built so the device is identical to the principle according to example 2. The value of d the total shear displacement between the rear edges is equal to the sum of the values move the shift of each drive, as shown on Fig.7.

Fig illustrates an assessment of the performance of such devices.

Curve (I) shows the device is composed of only two simple actuators of the pre-defined series. Movement is expressed in microns. The device is powered by a voltage of +1500/-500 Century

Curve (II) shows the shear stiffness of one section of the blade chord 141,5 mm), open article the Rhone rear edge. The internal structure is the structure of the classical type. Shearing force corresponds to the force which must be applied to the rear edges to move one relative to another.

Curve (III) shows the connection of the blade and devices in the Assembly.

Example 6

As shown in Fig.9, the device according to the invention may include and actually very back edge, two drives are in this case respectively of the upper and lower surfaces immediately adjacent to the trailing edge. The plane of symmetry of both drives are no longer parallel. The actuators A1 and A2 of the device are connected to their respective zones of fixation S1 in such a way as to form between them an angle that is optimal for the rear edge of the blade. The actuator A1 glued to their fastening area S2 on the upper side of the rear edge of the upper surface S of the airfoil, and an easy drive A2 glued to their fastening area S2 on the lower side of the rear edge to the lower surface I of the airfoil. Area S1 and the rear edge is located, following the chord, with the same side of the zone of fixation S2 actuators A1 and A2 of the device on a supporting plane.

Additionally can be made the connection between the upper and lower rear edges by means of elastomer With a low modulus, glued, nab is emer, at the level of the internal surfaces of the dual drive.

The device continuously overlaps a section of the supporting plane along its scope and provides a "composite" connection thus to reduce the flexibility of the drive to avoid buckling.

1. Flat actuator with a layered structure having two zones of fixation (S1, S2)intended for transmission generated by the relative movement of the shift, and at least three superimposed on each layer (1, 2, 3)comprising at least one layer of fabric, the warp and the weft of which consist of a rigid fibers arranged according to two directions of the plane (X, Y), forming cells lying adjacent parallelograms, and at least one flat active piezoelectric layer made with the ability to lengthen or shrink along the active direction, and each party of one layer is bonded over its entire surface to one side of the adjacent layer, wherein the layered structure is symmetric, contributing flat shear strain; the active direction of each flat piezoelectric layer is oriented along the same diagonal cells of each layer fabrics, the warp and the weft of which is oriented according to the same two directions (X, Y); zone of fixation (S1, S2) of the actuator having the form, pull the left along the first direction (X), located along opposite ends of the actuator according to the second direction (Y), so that each flat layer of fabric loaded along the respective diagonals of the cells, the parallelograms are deformed, causing it to move in the plane of the zone of fixation (S1, S2) parallel to each other, due to the first direction (X).

2. The actuator according to claim 1, characterized in that the layered structure formed from one active layer (1), located between the two tissue layers (2, 3).

3. The actuator according to claim 1, characterized in that the layered structure is formed by a single layer of fabric (1), located between the two active layers (2, 3).

4. Flat drive unit, characterized in that it consists of two established a Jack actuator, according to one of claims 1 to 3, two opposing zones of fixation (S2) are connected, and two active directions are not parallel, the other two opposing zones of fixation (S2) actuators configured to move along the first direction (X) with amplitude equal to the sum of the displacements of both single drives.

5. The bearing plane of the aircraft, including the upper and lower surface, and a driving device near the rear edge, characterized in that the drive device according to claim 4, the driving device has two opposing zones of fixation (S1), which are connected COO is responsible with the bottom surface (I) and upper surface (E).

6. Carrier plane according to claim 5, characterized in that the two opposing zones of fixation (S2), connected to each other, and a back edge located by following the chord, and on the other side of the two opposing zones of fixation (S1).

7. Carrier plane according to claim 5, characterized in that the two opposing interconnected zone of fixation (S1), and a back edge located by following the chord, on the same side of two opposing zones of fixation, with two opposing, interconnected zone of fixation (S1) is formed in the rear edge.