Actuator mounting method and method for producing an ice protection device as well as mounting device

Abstract

An actuator mounting method for mounting at least one actuator involves providing a skin structure and at least one actuator, and fixing the at least one actuator to the inner surface of the skin structure.

Claims

1. An actuator mounting method for mounting at least one actuator on or in a skin structure, comprising the following steps: a) providing a skin structure; b) providing at least one actuator configured to deform a surface area of the skin structure; and c) fixing the at least one actuator to an inner face of the skin structure, wherein step c) comprises the steps of: c1) positioning the at least one actuator on a punch for a planar pressing of the at least one actuator against the inner face of the skin structure; c2) holding the actuator on the punch by a releasable holding element; c3) pressing the actuator against the inner face of the skin structure by the punch; c4) connecting the actuator to the inner face; and c5) releasing or removing the punch.

2. The actuator mounting method of claim 1, wherein step c4) comprises the steps of: c4.1) materially bonding the actuator to the inner face; c4.2) gluing the actuator to the inner face; c4.2.1) applying an adhesive to the inner face or a surface of the actuator that is to be glued to the inner face, prior to attaching the actuator to the inner face; c4.2.2) curing the adhesive by pressing on the actuator according to step c3); and c4.3) interposing an electrical insulation layer between the actuator and the inner face.

3. The actuator mounting method of claim 1, wherein step c2) comprises the steps of: c2.1) holding the actuator on the punch using double-sided adhesive tape during the insertion into the skin structure or the attachment to the skin structure.

4. The actuator mounting method of claim 1, wherein step c3) comprises at least one the steps of: c3.1) moving the punch in a guided manner by a guide unit; c3.2) maintaining or keeping constant an application pressure by a force accumulator; and c3.3) supporting an outer face of the skin structure by a support fixture that is complementary to the outer face.

5. The actuator mounting method according of claim 1, wherein step a) includes providing the skin structure with at least one planar surface on the inner face of the skin structure; and step c) includes fixing the at least one actuator to the at least one planar surface.

6. The actuator mounting method of claim 1, wherein step b) includes: b.1) providing at least one piezoelectric actuator.

7. The actuator mounting method of claim 1, wherein step b) includes b.2) providing at least one first actuator for deforming a section of the surface area that is formed on a first longitudinal half of the skin structure, and providing at least one second actuator for deforming a section of the surface area that is formed on a second longitudinal half of the skin structure, and step c) includes c5) simultaneously fixing the at least one first actuator to the inner face of the first longitudinal half and of the at least one second actuator to the inner face of the second longitudinal half.

8. A production method for producing a mechanical ice protection unit for an aircraft for keeping a surface area of the aircraft free from ice and/or for de-icing the surface area, the production method comprising: a) providing a skin structure; b) providing at least one actuator configured to deform a surface area of the skin structure; and c) fixing the at least one actuator to an inner face of the skin structure, d) attaching a heat output device for heating at least part of the skin structure, wherein the skin structure includes on the outer face thereof the surface area to be kept free from ice and to be de-iced.

9. The production method of claim 8, wherein step d) comprises the steps of: d1) providing a heat output device that is formed for a linear heat output to generate a predetermined breaking point or a predetermined breaking line or a separation line in ice accumulating on the surface area; and d2) attaching the heat output device to the inner face of the skin structure in an area of a leading edge or of a stagnation line of a profile body to be formed by the skin structure.

10. A mounting device comprising: a punch configure to press, in a planar manner, at least one actuator against an inner face of a skin structure for an aircraft to which the at least one actuator is to be fixedly mounted; a releasable holder configure to hold the at least one actuator on the punch; and a press-on unit configured to press the punch with the at least one actuator against the inner face of the skin structure.

11. The mounting device of claim 10, further comprising: an adhesive application unit configured to apply an adhesive to the inner face or a surface to be bonded to the inner face of the at least one actuator prior to the attachment of the actuator to the inner face; and a curing unit configured to cure the adhesive while pressing on the actuator.

12. The mounting device of claim 10, wherein the holder has an adhesion structure for releasably gluing the at least one actuator to the punch.

13. The mounting device of claim 10, wherein a) the press-on unit has a guide unit configured to move the punch in a guided manner or a force accumulation element configured to maintain or keep constant an application pressure, or b) the mounting device has a support fixture configured to support the outer face of the skin structure while pressing the punch.

Description

(1) Embodiment examples of the invention will be explained in more detail below by means of the attached drawings, wherein:

(2) FIG. 1 shows a schematic, partially cut-away view of an aircraft, using an aeroplane as an example, wherein the leading edges of aerodynamic profile bodies of the aircraft, such as in particular wings, fins of the tail unit and engine inlets, are provided with a device for de-icing and/or for avoiding ice formation;

(3) FIG. 2 shows a schematic, partially perspective, partially sectioned view through an aerodynamic profile body, for example for forming a wing of the aircraft of FIG. 1, shown in a section along line II-II of FIG. 1, wherein the profile body is provided with the device for de-icing and/or for avoiding ice formation;

(4) FIG. 3 shows a schematic sectioned view of a section through the leading edge of the profile body of FIG. 2 with the device for de-icing and/or for avoiding ice formation, without the operation of a heat output device;

(5) FIG. 4 shows a view as in FIG. 3 during the operation of the heat output device;

(6) FIG. 5 shows a schematic view of a skin structure for forming the profile body, to which actuators for forming a mechanical ice protection unit of the device are to be mounted;

(7) FIG. 6 shows a principal view of a mounting device for mounting actuators to the skin structure of FIG. 5; and

(8) FIGS. 7 to 10 show a schematic view of longitudinal sections through the mounting device with the skin structure for clarifying various steps of a mounting method.

(9) Embodiment examples of an actuator mounting method as well as a production method that can be carried out using this actuator mounting method for producing a device 10 for de-icing and/or for avoiding ice formation will be explained in more detail below.

(10) The actuator mounting method is not limited to the use in devices for de-icing and/or for avoiding ice formation, but can generally be used for mounting an actuator in a skin-shaped body.

(11) To this end, initially embodiment examples of a device 10 that can be obtained using this method for de-icing and/or for avoiding ice formation on a surface area 14 of an aircraft 16 as well as the function thereof will be explained in more detail with reference to FIGS. 1 to 4, after that the individual steps of the mounting process will be addressed in more detail with reference to the remaining figures.

(12) The views in FIGS. 1 and 2 merely represent embodiment examples. Many other deviating embodiments of the device 10 are possible.

(13) FIG. 1 shows an aircraft 16 in the form of an aeroplane 20. The aeroplane 20 has wings 22 which are each formed by profile bodies 18, tail unit fins 24 and engine inlets 25. In the area around the leading edges 26 of the profile bodies 18 of the wings 22 as well as the tail unit fins 24 and the engine inlets 25, there is the surface area 14 on which ice can accumulate during flight.

(14) In order to counteract this, the aircraft 16 comprises a device 10 for de-icing and/or for avoiding ice formation on the surface area 14. The device 10 has a heat output device 12 for outputting heat to the surface area 14.

(15) The heat output device 12 is preferably not formed for an extensive heat output, but for a linear heat output along a heat output line 28. As a result of the linear output along the heat output line 28, any ice 30 accumulating on the surface area 14 can be linearly weakened and can be separated along the heat output line 28. In this respect, the heat output device 12 is formed for forming a predetermined breaking point or a predetermined breaking line 32 for the ice 30.

(16) In a preferred embodiment, the heat output device 12 is formed in such a way that the heat is output in a linear manner along the outermost leading edge 26 and in particular along the stagnation line 34 of the respective aerodynamic profile 36 of the respective profile body 18. The stagnation line 34 is the line that connects the stagnation points of the aerodynamic profile 36 with each other or, in other words, that line on an aerodynamic profile 36 along which, in the case of a corresponding approach air flow, shown in FIGS. 3 and 4 by the arrow and the speed vector v, is divided into streams either to either side or upwards and downwards. During flight, the highest pressure builds up along the stagnation line 34.

(17) In a further preferred embodiment, the heat output device 12 is formed in such a way that the heat is output along the momentary stagnation line 34 of the respective aerodynamic profile 36 of the respective profile body 18. This can be realised for example by means of a number of heating wires linearly attached in the area of the leading edge of the wing. Thus, it can be ensured even under flight conditions at different angles of attack of the wing surfaces or the wing profile that the ice is split up by the linear heat input on or near the respective stagnation line.

(18) The device 10 further has ice protection units 37 for removing ice and/or for avoiding ice accumulations in or on the sections 38, 39 of the surface area 14, which are divided by the heat output line 28 or the stagnation line 34.

(19) In the embodiment shown, a deformation unit 40 for deforming corresponding parts or sections 38, 39 of the surface area 14 is provided as an example of an ice protection unit 37.

(20) Further measures may be provided. For example, in the embodiment shown, a surface coating 42 for reducing ice adhesion forces is additionally provided on the surface area 14.

(21) According to a preferred embodiment, the device 10 is formed as a hybrid de-icing system 44 that carries out ice removal or the avoidance of ice formation on the basis of at least two principles.

(22) The heat output device 12 is preferably formed by an electrothermal system 46 that is formed as a subsystem of the hybrid de-icing system 44.

(23) In a preferred embodiment, the heat output device 12 has a heating wire 48 for the defined formation of a predetermined breaking point on the stagnation line 34 of the profile 36.

(24) To this end, in order to design the device 10 in the area of the leading edge 26 of the profile body 18, which is used for example for forming the wing 22 or for forming tail unit fins 24 or for forming an engine inlet 25, the electrothermal heating wire 48 is installed along the stagnation line 34 of the profile 36, as can be seen in particular from FIG. 2. In a preferred embodiment, the heating wire 48 is embedded in a matrix of fastening material such as in particular an epoxy resin matrix 50.

(25) Instead of using an embedding matrix, the heating wire 48 can also be fixed to the inner face of the profile 36 by means of a thin film adhesive. As a preferred heating wire 48, a single-wire jacket heating conductor with a slim, circular cross section is used. Alternatively, however, also a carbon fibre cord can be used as a heating element. For example, this is impregnated with epoxy resin and/or has glass layers wrapped around it for electrical insulation.

(26) Instead of the heating wire 48, however, the heat output device 12 may also use a piezo actuator that is controlled for example with a high frequency and thus outputs both thermal and mechanical energy. Such a piezo actuator of the further embodiment, which is not shown here in any more detail, without the heating wire 48 should be designed such that it outputs the heat along the heat output line 28 in such a way that a predetermined breaking point is formed.

(27) The device 10 shown here has, apart from the heat output device 12, also an electromechanical de-icing system 52 as a further subsystem of the hybrid de-icing system 44. The electromechanical de-icing system 52 can be regarded as an example of the deformation unit 40. Preferably, the electromechanical de-icing system 52 has at least one piezo actuator 54.

(28) Particularly preferably, the deformation means 40 and the electromechanical de-icing system 52 thereof have a first deformation unit 56 and a second deformation unit 57. The first deformation unit 56 is used for deforming a first section 38 of the surface area 14 on a first side of the heat output line 28. In the example shown in FIG. 2, where the profile body 18 is part of the wing 22, the first section 38 is for example the section located above the stagnation line 34 of the surface area 14 enclosing the leading edge 26. Correspondingly, the second section 39 that is to be deformed by the second deformation unit 57 is, in the example shown, the section of the leading edge surface area 14 that is below the stagnation line 34.

(29) Correspondingly, the electromechanical de-icing system 52 preferably has at least two piezo actuators 54, 55, namely at least one first piezo actuator 54 for the first deformation unit 56 and at least one second piezo actuator 55 for the second deformation unit 57. The first and the second sections 38, 39 may in particular be formed by a first and second longitudinal halves of the profile body 18.

(30) Correspondingly, for example for designing an electromechanical de-icing system 52, the installation of at least two piezo actuators 54, 55 in the area of a leading edge 26 of an aerodynamic profile 36 is provided, such as for example the profile body 18 of a wing 22. The piezo actuators 54, 55 are located, in the flow direction, behind the linear heat output areaheat output line 28defined by the heating wire 48. They are thus used for removing ice accumulations behind the stagnation point of the profile 36 and for removing ice deposits on back-flowing and solidifying drops by means of the electro-thermal system 46.

(31) As piezo actuators 54, 55 in particular d.sub.33 actuators having for example a length of approx. 30 mm, a width of approx. 10 mm and a height of approx. 2 mm may be used. For more details in respect of the design of the piezo actuators, reference is expressly made to WO 2007/071231 A1.

(32) In order to allow a mechanical coupling into the structure that is as efficient as possible, planar surfaces 82 to be applied to the inner face 76 of the profile 36 (e.g. the wing profile 74) are to be provided for the preferred cuboid piezo actuators 54, 55. The preferred cuboid piezo actuators are in particular advantageous because they can be obtained as low-cost standard components. Alternatively, also form-adapted piezo actuators may be used that have the same curved contour as the profile 36, in order to provide for a mechanical coupling into the structure that is as efficient as possible.

(33) In the preferred embodiment, the device 10 for de-icing and/or for avoiding ice formation preferably also has means for reducing ice adhesion to the surface area 14 as a hybrid de-icing system 44. These means can be regarded as a further subsystem for de-icing. In particular, these means include a surface coating 42.

(34) In a preferred embodiment, the surface area 14 is coated around the leading edge 26 of the aerodynamic profile 36 or, for example, an entire surface area of the profile body 18, for example the wing 22, is coated in such a way that the surface has minimal adhesion characteristics between ice (or water) and the profile surface. For example, a NACA-0012 aluminium wing profile having a nanostructured, superhydrophobic surface area 42 in the area of the leading edge 26 (e.g. Hydrobead) is provided as a profile body 18.

(35) Accordingly, FIG. 2 shows the preferred embodiment of the device 10 with the heat output device 12 provided with the heating wire 48 along the stagnation line 34 as the electro-thermal system 46, having the first and second deformation units 56, 57 formed with piezo actuators 54, 55 for deforming a first section and a second section 38, 39 of the surface area 14 formed the deformation unit 40 as an electromechanical de-icing system 52 and having the surface coating 42 as a further subsystem of the hybrid de-icing system 44.

(36) An operating mode of such a hybrid de-icing system 44 will be explained in more detail below with reference to the views in FIGS. 3 and 4.

(37) FIG. 3 shows a schematic diagram of the aerodynamic profile 36 by way of the example of the profile of the wing 22 with a leading edge 26 that is completely covered with ice 30. The indicated heating wire 48 that is glued to the inner face of the profile 36 at the level of the stagnation line 34, for example, has at no time been electrothermally heated. Even if by controlling the indicated piezoelectric actuators 54, 55, a bonding in the interface between the ice and the surface in the surface area 14 of the profile 36 is broken up, the ice layer surrounding the leading edge 26 of the profile 36 will still remain in the same place because the aerodynamic forces of the flow, indicated by the speed vector v, continue to press the ice layer against the leading edge 26 of the profile 36.

(38) By contrast, FIG. 4 shows a schematic diagram of the profile 36 of, for example, the profile body 18 forming the wing 22 with an, e.g. permanently, operated heating wire 48 that is glued onto the inner face of the profile 36 at the level of the stagnation line 34. The introduction of thermal energy, which in a two-dimensional view is punctiform and in a three-dimensional view is linear, generates a predetermined breaking point or a predetermined breaking line 32, which is used for the purpose of partitioning or splitting up the accumulation of ice 30 on the stagnation line 34 of the profile 36 of the wing 22 into an upper proportion 60 and a lower proportion 61 of the ice layer. In more general terms, the ice 30 is split up along the predetermined breaking line 32 into a first portion 60 and a second portion 61. As a result, both ice portions 60, 61 can be removed by the indicated piezo electric actuators 54, 55.

(39) The operating modes of the hybrid de-icing system 44, as depicted in FIGS. 3 and 4, will be explained in even more detail below by way of an example of a possible embodiment of a method for de-icing or for avoiding ice formation on aircraft, which can be carried out for example using the device 10.

(40) As a result of the use for example of a heating wire 48 on the stagnation line 34 of the profile 36 of a wing 22 or the like, which heating wire 48 is glued onto the inner face of the profile 36, thermal energy is linearly transferred onto the profile 36 in the direction of the wingspan. In more general terms, a heat output of a heat output device 12 is carried out linearly in a three-dimensional view or in a punctiform manner in a two-dimensional view, as shown in FIG. 4. This requires the layer of ice 30 surrounding the leading edge 26 to be cut up and can be regarded as an intended introduction of a predetermined breaking point or a predetermined breaking line 32, which is used for partitioning the ice accumulation into a first and a second ice half, for example an upper ice half and a lower ice half.

(41) What is of particular advantage is the joint use of a heating wire 48 for forming the hybrid de-icing system 44 in conjunction with a deformation of a surface area 14 of the profile 36 by means of piezo electric actuators 54, 55.

(42) If one was to go without the heating wire 48, then the piezo actuators 54, 55 would still be able to deform the surface of the profile 36 of the wing 22 and thus to break up the bonding in the interface between the ice and the surface, however, the ice 30 released from the surface would still be pressed onto the profile 36 of the wing 22 by the aerodynamic stagnation pressure of the approach flow. Thus, the surface area 14 is ultimately not freed from ice accumulation, see FIG. 3. As a result of the partitioning into several sections or proportions 60, 61, for example an upper and a lower ice half, by means of the heat output device 12, for example by means of the heating wire 48, a potential problem of pressing the ice 30 against the profile 36 is avoided, see in this respect FIG. 4, and in addition, the effect of the aerodynamic flow against the profile 36 and of the forces acting on the ice 30 as a result, can be utilised.

(43) Thus, the heating wire 48, as opposed to electrothermal systems or heat output devices using heating mats, is not used for an extensive thermal removal of ice accumulations on the aerodynamic profile 36, such as for example of the wing 22, but for a linear breaking up of the ice layer.

(44) Accordingly, a de-icing method that can be carried out for example using the device 10 for de-icing a surface area 14 of an aircraft 16 and/or for avoiding ice formation on the surface area 14 of the aircraft 16, includes the step of introducing heat along a line on the surface area 14, in order to form a predetermined breaking line 32 in ice 30 accumulating on the surface area 14, or a separation line in ice accumulating on the surface area or in water drops accumulating on the surface area.

(45) By skillfully utilising the approach flow, ice can thus possibly be removed by breaking up the ice along a predetermined breaking line.

(46) More preferably heat is introduced along a heat output line 28 for forming a predetermined breaking line 32 or a separation line along a stagnation line 34 of an aerodynamic profile 36.

(47) More preferably the de-icing method further includes at least one of the steps of deforming the surface area 14 in order to break up ice along the predetermined breaking line 32 and/or in order to remove ice broken up along the predetermined breaking line 32 or water accumulations on the sides of the separation line and/or to provide a surface area 14 with surface characteristics that reduce ice adhesion forces, in particular by means of an appropriate surface coating 42.

(48) In a preferred embodiment, the heating wire 48 of the electrothermal system 46 is operated in a permanent running-wet-anti-icing mode. To achieve a low energy consumption, however, the heating wire can alternatively also be operated in a cyclic de-icing mode in order to allow the removal of the separated proportions 60, 61 from ice 30 on the profile 36 by means of the deformation means 40.

(49) The deformation of the surface area 14 is preferably carried out by piezo actuators 54, 55. In particular, the deformation of the surface of the profile 36 is carried out by controlling the piezo actuators 54, 55 in the range of the resonance frequency of the structure, in this case a low control voltage with a contact voltage of 0 V is preferably used, or by a quasi-static excitation of the piezo actuatorshere, a high amplitude and a contact voltage of >0 V is preferably usedas a result of which the ice accumulations in the area in the flow direction behind the stagnation line 34 of the profile 36 can be removed.

(50) A further possible control approach lies in a continuous dynamic control of the piezo electric actuators 54, 55 with a square-wave signal having a defined edge steepness at a repeat frequency of for example 1 Hz. The square-wave signal is used to bring the wing structure into resonance and this, in combination with the static excursion, has a further positive effect on the cracking of the ice 30.

(51) If for example two or more piezo actuators 54, 55 are installed on the first and second sections 38, 39 of the profile 36, respectively, for example on the upper side and the lower side of the profile 36 of the wing 22, there is further the possibility of controlling the actuators 54, 55 individually in order to generate any desired form of vibration on the surface of the profile 36, for example a type of wave transversely to the surface of the surface area 14.

(52) The direction of movement of the piezo actuators 54, 55 can be in the direction of the wingspan or in the flying direction (d.sub.33 effect) or in a planar manner (d.sub.31 effect).

(53) As a result of the icephobic properties of a superhydrophobic coating 42, the adhesive bonding forces between the ice 30 and the surface of the profile 36 are reduced to a minimum. As a result, an energy-efficient removal of all ice accumulations on the profile 36 is made possible.

(54) In order to provide evidence of functionality, a profile 36 of the wing 22 was caused to ice up under real flight conditions in an icing wind tunnel on a laboratory scale. As a result of the use of all three subsystems of the hybrid de-icing system 44, all of the ice accumulations adhering to the wing profile were removed. In this process, the three subsystems were used as the same time. A comparison of the energy requirements of the hybrid de-icing system 44 with a de-icing system already certified for flight operation, in particular a purely electrothermal de-icing system, showed very clear energy savings.

(55) Further embodiment examples and modifications to the device 10 deal with a reduction of the probability of failure.

(56) Thus, the heat output device 12 could, in order to ensure redundancy of a hybrid de-icing system 44, include a plurality of heating wires 48.

(57) For example, a heating wire 48 could be provided directly on the stagnation line 34 and further heating wires (not shown in more detail) are provided in the area around the stagnation line 34.

(58) Also, in each case a plurality of piezo actuators 54, 55 could be used on the respective sections 38, 39.

(59) Such devices 10 are suitable for carrying out a particularly energy-efficient method for de-icing or for avoiding ice formation. To this end, however, an electromechanical de-icing system 52 is advantageous that allows a deformation of a surface area of the profile body 18 that is as close as possible to the leading edge.

(60) A mounting device 70 and an actuator mounting method for mounting actuators 54, 55 will be explained in more detail below by means of the views shown in FIGS. 5 to 10, which allows such an attachment. Although the mounting device 70 and the actuator mounting method will be explained for the purpose of illustration by means of the embodiment example of a hybrid device 10, applicability is not limited to this. In particular, they can be used in any desired place where the formation of a skin structure 72 that is highly curved or encloses a tight space is to take place by means of actuators.

(61) The actuator mounting method is suitable for mounting at least one actuator 54, 55 and is used in particular for producing a mechanical ice protection unit 37e.g. the electromechanical de-icing system 52for an aircraft 16 for avoiding ice formation on the surface area 14 and/or for de-icing the surface area 14 of the aircraft 16. The actuator mounting device comprises in particular the following steps:

(62) a) providing a skin structure 72, on the outer face of which the surface area 14 to be de-iced is to be formed,

(63) b) providing at least one actuator 54, 55 that is suitable for deforming the surface area 14 of the skin structure 72, and

(64) c) fixing the at least one actuator 54, 55 to the inner face of the skin structure 72.

(65) In the example of the device 10 shown in FIG. 2, a basic condition for the mounting of the piezo actuators 54, 55 is the production of a thin skin structure 72 to which the piezo actuators 54, 55 are glued.

(66) In this example, a NACA-0012 wing profile is used that was milled from a whole piece. FIG. 5 shows the skin structure 72 of the profile 36 of the profile body 18. This is for example a profile 36 that was milled from a whole piece for a wing 22 in the form of a symmetrical slim NACA 0012 profile. Of course, the mounting method can also be applied to any other profile 36 of the possible profile bodies 18 of the aircraft.

(67) On the inner face 76 of the skin structure 72, a planar surface 82 for the later gluing of the preferably cuboid piezoelectric multilayer actuators is in each case formed in the area of a first longitudinal half 78 and of a second longitudinal half 80.

(68) The surface on the inner face 76 of the profile 36, to which the piezo actuators 54, 55 are later glued, should have a suitable roughness value and should be cleaned prior to further use. Further, a (preferably) planar surface 82 should be provided in this area.

(69) The actuator 54, 55 can alternatively also be glued to a curved skin structure 72. In this case, the skin structure 72 and the actuator 54, 55 preferably have the same curvature.

(70) Subsequently, a mounting device 70 is used for mounting the actuators 54, 55, such as for example shown in a schematic demonstration design in FIG. 6 and indicated in FIGS. 7 to 10.

(71) The mounting device 70 has a punch 86, a press-on unit 88, holding means 90 and a support fixture 92.

(72) The punch 86 is used for receiving and pressing the actuators 54, 55 against the inner face 76 of the skin structure 72.

(73) To this end, the punch 86 includes a reception area 84, the surface shape of which is complementary to that part of the surface structure of the inner face 76 to which the actuators 54, 55 are to be fixed. If for example the planar surfaces 82 are provided, then the reception area 84 is formed with planar surfaces that are inclined at an appropriate angle. To this end, the punch 86 may for example have a generally trapezoidal form. The holding means 90 are formed for temporarily holding the actuators 54, 55 on the punch 86.

(74) The press-on unit 88 is used for pressing the punch 86 against the inner face 76. To this end, in particular a guiding unit 94 and a compression force generation unit 95 for the guided movement of the punch 86 and for pressing on is provided. In order to maintain a constant pressure, in particular a force accumulation element such as e.g. a Belleville spring 97 is provided.

(75) The support fixture 92 is used for supporting the thin skin structure 72 during the pressing-on process. To this end, the surface of the support fixture 92 has a form complementary to that of the surface area 14 of the skin structure 72.

(76) FIG. 6 shows a demonstration design of a mounting device 70 for mounting actuators on a small-scale profile 36 for wind tunnel trials. What is shown are the profile 36, lateral guide rails 96 for forming the guide unit 94, the punch 86 with piezo actuators 54, 55 adhering thereto, a polyamide mould 98 as an example of the support fixture 92 as well as nuts 100 for mounting. The compression force generation unit 95 includes threaded bars 112. The nuts 100 can be turned by means of screwdrivers (not shown) towards the inner face 76 by the threaded bars 112, in order to press the punch 86 against the inner face 76. Between the nuts 100 and the punch 86, Belleville springs 97 are provided as force accumulator elements for maintaining a constant pressure. However, also washers 99 may be provided that are positioned between the nut 100 and the Belleville spring 97.

(77) The gluing process will be explained in more detail below by means of the views shown in FIGS. 7 to 10.

(78) If the skin structure 72 and the actuators 54, 55 are provided, then initially the step of applying the actuators 54, 55 to the punch 86 is carried out. An embodiment example of this step of applying or attaching the actuators to the punch 86 will be explained in more detail hereafter.

(79) An adhesive 102 for gluing the actuators to the inner face is applied onto the actuators.

(80) To this end, in a preferred embodiment, for example a thin layer of a film adhesive 104 is cut to size and is applied to that side of the piezo actuator 54, 55 that is later to be connected to the profile 36.

(81) If the inner face of the profile 36 is electrically conductive, an insulation layer 106 from an electrically insulating material is provided between the inner face and the actuators 54, 55.

(82) To this end, if the profile is electrically conductive, for example a prepreg glass fibre fabric 108 for forming the insulation layer 106 is provided for electrical insulation from the carrier structure. The required insulation distance is adjusted via the number of prepreg layers. The higher the electrical control voltage is selected to be, the greater the selected insulation distance will be.

(83) On both sides of the punch 86, which is here provided with a trapezoidal cross section, one piezo actuator 54, 55 each is applied by means of the holding means 90, which for example includes an adhering medium, such as for example a double-sided adhesive tape 110 for a temporary gluing with a view to releasing it again later after the gluing process, or for a physical type of adhesion (e.g. suction via vacuum or electrostatic charging).

(84) If sensitive piezo actuators 54, 55 are used it is advantageous if no transverse point forces are applied to the surface of the piezo actuator 54, 55. As a result, a double-sided adhesive tape 110 has proven to be particularly suitable as a holding means 90.

(85) In this way, the later positioning of the piezo actuators 54, 55 within the profile 36 is determined by the positioning of the piezo actuators 54, 55 on the punch 86. For example, the piezo actuators 54, 55 can be aligned using markings on the punch 86, using stops on the punch or by any other additional orientation means (none of them shown).

(86) After attaching the actuators 54, 55 to the punch 86, the step of material bonding, in particular gluing, of the actuators 54, 55 to the skin structure 72 can take place, which will be explained in more detail hereafter.

(87) For an exact positioning and maintaining the angle from the punch 86 within the profile 36 it is advantageous if the punch 86 is guided, e.g. by means of guide rails 96 or threaded bars 112. The punch 86 can be guided either laterally on both sides, laterally on one side or, in the case of open profiles, also from the rear.

(88) The press-on pressure should be kept constant during the gluing step whilst the adhesive 102 cures. This can be achieved for example by means of force accumulation elements such as e.g. Belleville springs (not shown). The press-on pressure is counteracted with a negative mouldthe support fixture 92of the profile 36 (made e.g. from a polyamide), in order to maintain the shape of the profile 36.

(89) For curing the adhesive 102, a curing device is provided that is formed to carry out the curing step for the respective adhesive 102.

(90) For example, the curing process of the adhesive 102 is carried out in an oven (not shown) at a suitable temperature, preferably below the Curie temperature (120 C.). In order to maintain the temperature, this can be controlled for example using a control bore near the positioning location of the piezo actuator on the punch 86.

(91) By hardening at a suitable temperature, a mechanical prestress can be introduced as required or desired. The mechanical prestress protects the actuator better from tensile stress and/or from defects as may occur in particular in resonance operation.

(92) Optionally, the heating wire 48 may, with the same principle, in addition be glued to the inner face 76 of the profile 36 in the region of the stagnation line 34.

(93) The step of removing the punch 86 after the gluing of the piezo actuators 54, 55 to the profile 36 will be explained in more detail below.

(94) Once the piezo actuators 54, 55 have been glued on, the press-on pressure is released and the punch 86 can be removed. If a double-sided adhesive tape 110 is used, a simplified removal of the punch 86 proves to be particularly suitable in a warm condition, because only a low force will be required for releasing the adhesive tape 110 from the piezo actuators 54, 55.

(95) FIG. 7 shows schematically the components used during the application process of the actuators to the skin structure.

(96) FIG. 8 shows schematically the step of applying the actuators 54, 55 to the punch and the insertion of the punch 86 into the profile 36.

(97) FIG. 9 shows schematically the step of pressing the punch 86 on.

(98) FIG. 10 shows schematically the step of withdrawing the punch 86.

(99) Apart from the possible use of the actuator mounting method shown in the course of the production of ice protection systems, the method can also be used for mounting actuators for other purposes of use. Examples of this are shown in WO 2007/071231 A1, to which reference is expressly made for further details of the further possible purposes of use.

LIST OF REFERENCE NUMERALS

(100) 10 Device for de-icing and/or for avoiding ice formation 12 Heat output device 14 Surface area 16 Aircraft 18 Profile body 20 Aeroplane 22 Wing 24 Tail unit fins 25 Engine inlet 26 Leading edge 28 Heat output line 30 Ice 32 Predetermined breaking line (separation line) 34 Stagnation line 36 Profile 37 Ice protection unit 38 First section 39 Second section 40 Deformation unit 42 Surface coating 44 Hybrid de-icing system 46 Electro-thermal system 48 Heating wire 50 Epoxy resin matrix 52 Electromechanical de-icing system 54 First piezo actuator 55 Second piezo actuator 56 First deformation unit 57 Second deformation unit 60 First portion of the ice layer 61 Second portion of the ice layer 70 Mounting device 72 Skin structure 76 Inner face 78 First longitudinal half 80 Second longitudinal half 82 Planar surface 84 Reception area 86 Punch 88 Press-on unit 90 Holding means 92 Support fixture 94 Guide unit 95 Compression force generation unit 96 Lateral guide rail 97 Belleville spring 98 Polyamide mould 99 Washer 100 Nut 102 Adhesive 104 Foil adhesive 106 Insulation layer 108 Prepreg glass fibre fabric 110 Double-sided adhesive tape 112 Threaded bars