Propeller of an aeroplane turbine engine and method for de-icing same

Abstract

The invention relates to a propeller (1) of an aircraft turbine engine, comprising a cone (2) and a plurality of blades (3), the propeller (1) comprising a plurality of electrical de-icing members (4) rigidly connected to a wall (30) of the blades (3), and a control system (6) electrically connected to the electrical de-icing members (4) and comprising at least one electrical switch (7A) having a variable switching duty cycle which is configured, using an input electrical power (Pe), to distribute an output electrical power (Ps) to the electrical de-icing members (4) and to emit a dissipated electrical power (Pd) in the form of heat, at least one electrical switch (7A) of the control system (6) being mounted on an inner face (21) of a wall (20) of the cone (2) so as to transfer the dissipated electrical power (Pd) by thermal conduction into the wall (20) of the cone (2).

Description

Aircraft turbomachine propeller and its deicing process

[0001] The present invention relates to the field of aircraft turbomachines and more particularly aims at de-icing a propeller of an aircraft turbomachine.

[0002] As is known, an aircraft turbomachine comprises a propeller upstream of the air inlet of the turbomachine. The propeller comprises a cone enclosing a hub and a set of blades extending radially from the hub. The propeller is driven in rotation by a rotating shaft of the turbomachine, in practice via a speed reducer known to those skilled in the art under the designation “Reduction Gear Box (RGB)”.

[0003] During aircraft flight, ice may form on the propeller. The accumulation of ice is undesirable because it can change the mass of the propeller, as well as its balance around the axis of rotation and its aerodynamics. In addition, the detachment of a block of ice from the propeller can cause it to be ingested into the turbomachine, which is likely to damage it.

[0004] To prevent the formation and / or accumulation of ice, it is known to position heating elements on the blade wall at the leading edge and, in some cases, on the cone wall. The heating elements are in the form of heating mats comprising electrical resistors, which are activated in the presence of icing conditions. This prevents the formation of ice and / or loosens the ice which is ejected from the turbomachine by the centrifugal force linked to the rotation of the propeller.

[0005] It is known from application FR3096080A1 to electrically power the heating elements by a permanent magnet alternator mounted in the accessory box, known to those skilled in the art under the designation "Accessory Gear Box (AGB)". From a torque taken from a rotating shaft of the turbomachine, the permanent magnet alternator produces a direct electric current. An inverter converts the direct electric current into alternating electric current which is transmitted by a rotating transformer to the heating elements mounted in the rotating propeller. The rotating transformer comprises a rotor coupled in rotation to the propeller and a stator mounted in a fixed part of the turbomachine, for example in the cavity delimited by the compressor casing.

[0006] To ensure de-icing that is both effective and without the risk of overheating the propeller, it is known to control the electrical power supplied to the heating elements with a set of switches. In practice, each switch is in the form of a power electronics component, for example, a transistor (IGBT, etc.). The set of switches has a switching duty cycle that can be adjusted depending in particular on the climatic conditions and the operating speed of the turbomachine. The set of switches must be mounted between the rotating transformer and the heating elements to limit itself to a single rotating transformer for all the heating elements. This requires positioning the set of switches in the cavity delimited by the cone in a manner centered relative to the rotating axis of the cone to avoid an unbalance effect.

[0007] In practice, the switch assembly dissipates part of the electrical power transmitted by the rotating transformer as heat, which can reach a few percent. Such heating of a power electronics component is undesirable and requires the integration of a ventilation device in the cone, which increases the on-board mass, complexity and costs.

[0008] The invention thus aims to eliminate at least some of these drawbacks.

[0009] Patent EP2218643B1 discloses deicing the blades of an aircraft propeller with internal resistors whose power supply is controlled by semiconductor switches. The closing of the switches is controlled by an optical pulse received by a photoelectric sensor mounted downstream of the cone. Patent EP3135587B1 discloses deicing a fixed part of an aircraft, in particular the air intake, the fuselage or the wing.

[0010] Additionally, climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those already in operation, requiring the implementation of technological solutions to ensure their compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0011] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

[0012] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0013] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

[0014] To this end, the invention is the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft. PRESENTATION OF THE INVENTION

[0015] The invention relates to an aircraft turbomachine propeller comprising a cone and a plurality of blades, the cone extending along a longitudinal axis oriented from upstream to downstream and being configured to be driven in rotation by a shaft of the aircraft turbomachine, the cone comprising a wall with an internal face and an external face, the propeller comprising: a plurality of electrical de-icing members secured to a wall of the blades in order to de-ice them, a control system electrically connected to the electrical de-icing members and comprising at least one electrical switch with a variable switching duty cycle configured, from an input electrical power, to distribute an output electrical power to the electrical de-icing members and to emit dissipated electrical power in the form of heat.

[0016] The invention is remarkable in that at least one electrical switch of the control system, called an “electric de-icing switch”, is mounted on the internal face of the wall of the cone so as to transfer the electrical power dissipated by thermal conduction in the wall of the cone.

[0017] The invention advantageously makes it possible to promote the cooling of the control electronics mounted in the propeller cone to ensure de-icing of the blades. Mounting the electrical switches on the cone wall makes it possible to transfer the electrical power dissipated in the form of heat by the electrical switches into the cone wall by thermal conduction. The heat emitted by the electrical switches is thus advantageously dissipated efficiently to the outside instead of accumulating inside the cone. No cooling device is necessary in the cone. Such positioning of the electrical switches also advantageously makes it possible to contribute directly to de-icing the propeller cone, since the electrical power dissipated in the form of heat by the electrical switches heats the cone wall by thermal conduction.

[0018] According to one aspect of the invention, the defrosting electrical switch(es) have a global center of inertia belonging to the longitudinal axis. This avoids an unbalance effect in the cone.

[0019] According to one aspect of the invention, the control system comprises a plurality of electrical defrosting switches, the electrical defrosting switches being arranged on at least one section of the cone extending transversely relative to the longitudinal axis. The electrical defrosting switches are advantageously arranged longitudinally relative to the cone depending on the defrosting requirement which depends on the flow conditions of the incoming air flow.

[0020] According to a first aspect of the invention, the propeller comprises: a plurality of electrical de-icing members secured to the wall of the cone and arranged on at least one section of the cone extending transversely relative to the longitudinal axis and having a given longitudinal position called the “reference de-icing position”, the electrical de-icing switches being arranged on a section called the “upstream section” extending upstream of the reference de-icing position or on a section called the “downstream section” extending downstream of the reference de-icing position.

[0021] The electrical defrosting devices thus ensure defrosting at the area most prone to frost, where the incoming air flow is attached to the wall. The electrical defrosting switches located upstream ensure defrosting at the leading edge of the cone, at the point where the air flow is detached from the wall, where the need for defrosting is less. The need for defrosting is also less further downstream of the cone.

[0022] According to a second aspect of the invention, the propeller comprises: a plurality of electrical de-icing members mounted integral with the wall of the cone and arranged on at least one section of the cone extending transversely relative to the longitudinal axis and having a given longitudinal position called the “reference de-icing position”, the electrical de-icing switches being arranged on a section called the “upstream section” extending upstream of the reference de-icing position, and on a section called the “downstream section” extending downstream of the reference de-icing position.

[0023] Such an architecture advantageously allows significant defrosting of the cone over a large portion. Cooling of the control system is also improved.

[0024] According to one aspect of the invention: the electrical defrosting switches arranged on the upstream section are configured to intermittently electrically supply at least one electrical defrosting member, and the electrical defrosting switches arranged on the downstream section are configured to continuously electrically supply at least one electrical defrosting member.

[0025] The electrical de-icing switches in the upstream section thus dissipate more electrical power in the form of heat than in the downstream section, which allows for better de-icing of the upstream section, which is more exposed to frost. The electrical de-icing switches in the downstream section thus dissipate power continuously, preventing water that has run off following de-icing of an upstream section from refreezing, and possibly allowing it to evaporate, preventing any risk of ice formation downstream of the downstream section.

[0026] According to one aspect of the invention: the cone comprises a downstream part configured to be coupled in rotation to a shaft of the turbomachine and an upstream part fixed in a removably manner on the downstream part, at least one section extends in the upstream part and / or at least one section extends in the downstream part.

[0027] Such an architecture advantageously allows easy maintenance of the electrical equipment mounted in the cone.

[0028] According to one aspect of the invention, the propeller comprises a plurality of access openings formed in the wall of the cone at the downstream portion. This allows the de-icing electrical switches to be disconnected before disassembling the upstream portion of the cone during maintenance.

[0029] According to one aspect of the invention, the electrical defrosting members are in the form of resistive elements or piezoelectric elements.

[0030] According to a preferred aspect of the invention, the electrical switches of the control system are in the form of thyristors, field effect transistors, bipolar transistors and / or insulated gate bipolar transistors.

[0031] According to a preferred aspect of the invention, the wall of the cone has a thermal conductivity greater than 20 Wm-1.K-1, preferably greater than 150 Wm-1.K-1, and preferably comprises aluminum or graphene. This promotes thermal exchanges between the wall of the cone and the defrosting electrical switches.

[0032] According to a preferred aspect, said at least one electric defrosting switch is screwed to the wall of the cone, preferably at an excess thickness of the wall of the cone. This promotes heat exchange by conduction between the wall of the cone and the electric defrosting switches.

[0033] According to a preferred aspect, the propeller comprises at least one thermally conductive strip which is mounted on the internal face of the cone in contact with at least one defrosting electrical switch. This promotes thermal exchanges by conduction between the wall of the cone and the defrosting electrical switches.

[0034] The invention also relates to a method for deicing an aircraft turbomachine propeller as described previously, in which: from an input electrical power, each electrical switch distributes an output electrical power to the electrical deicing members to deice the blades and emits dissipated electrical power in the form of heat, said at least one deicing electrical switch transfers the dissipated electrical power by thermal conduction into the wall of the cone to ensure the cooling of the control system and the deicing of the wall of the cone simultaneously.

[0035] The invention also relates to a method for maintaining an aircraft turbomachine propeller, consisting of: Disconnecting said at least one de-icing electrical switch via said at least one access opening, then Dismantling the front part of the cone from the downstream part of the cone.

[0036] The invention also relates to an aircraft turbomachine comprising a rotating transformer and a propeller as described above, the rotating transformer comprising a rotor coupled in rotation to the propeller and a stator mounted fixedly in the aircraft turbomachine, the rotating transformer being configured to transmit an alternating electric current to the propeller control system.

[0037] The aircraft turbomachine is in the form of a turboprop. PRESENTATION OF FIGURES

[0038] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0039] This is a schematic perspective representation of an aircraft turbomachine propeller according to one embodiment of the invention.

[0040] This is a schematic perspective representation of an aircraft turbomachine propeller according to another embodiment of the invention.

[0041] This is a schematic representation in longitudinal half-section of the propeller according to a first embodiment of the invention.

[0042] This is a schematic cross-sectional representation of the electrical defrost switches of the.

[0043] This is a schematic representation in longitudinal half-section of the propeller according to a second embodiment of the invention.

[0044] This is a schematic representation in longitudinal half-section of the propeller according to a third embodiment of the invention.

[0045] This is a schematic representation in front view of an electrical defrosting switch mounted on the cone wall with thermally conductive elements according to one embodiment of the invention.

[0046] Here are two schematic representations in profile view of the mounting of an electric defrosting switch according to two alternative embodiments of the invention.

[0047] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0048] With reference to Figures 1 and 3, the invention relates to a propeller 1 of an aircraft turbomachine comprising: a cone 2 extending along a longitudinal axis X oriented from upstream to downstream, the cone 2 being configured to be driven in rotation by a shaft of the aircraft turbomachine and comprising a wall 20 with an inner face 21, which is turned towards the longitudinal axis X, and an outer face 22, opposite the inner face 21, blades 3, electrical de-icing members 4 secured to a wall 30 of the blades 3 in order to de-ice them, a control system 6 electrically connected to the electrical de-icing members 4 and comprising one or more electrical switches 7A of variable switching duty cycle configured, from an input electrical power Pe, to distribute an output electrical power Ps to the electrical de-icing members 4 and to emit in the form of heat a dissipated electrical power Pd.

[0049] According to the invention and as illustrated in Figures 1 and 3, one or more electrical switches 7A of the control system 6, called “electrical de-icing switches”, are mounted on the internal face 21 of the wall 20 of the cone 2 so as to transfer the dissipated electrical power Pd by thermal conduction in the wall 20 of the cone 2.

[0050] The invention advantageously makes it possible to promote the cooling of the control electronics mounted in the propeller cone to ensure the de-icing of the blades 3. The mounting of the electrical switches 7A on the wall of the cone 2 in fact makes it possible to transfer the electrical power dissipated in the form of heat by the electrical switches 7A into the wall of the cone 2 by thermal conduction. The heat emitted by the electrical switches 7A is thus advantageously dissipated efficiently to the outside instead of accumulating inside the cone 2. No cooling device is necessary in the cone 2. Such a positioning of the electrical switches also advantageously makes it possible to contribute directly to the de-icing of the cone 2 of the propeller, because the electrical power dissipated in the form of heat by the electrical switches heats the wall of the cone 2 by thermal conduction.

[0051] With reference to the, the propeller 1 is rotatably mounted along the longitudinal axis X upstream of the aircraft turbomachine, more precisely upstream of the air inlet (not shown). The propeller 1 is driven in rotation by a rotating shaft of the turbomachine, in practice via a speed reducer known to those skilled in the art under the designation “Reduction Gear Box (RGB)”. Upstream and downstream are defined relative to the longitudinal axis X of the cone 2 of the propeller 1, the apex of which extends upstream and the base downstream. The blades 3 extend radially from the cone 2. The radial direction is defined relative to that of the longitudinal axis X.

[0052] The invention has a particular advantage in the case of a turboprop propeller 1, which has a cone 2 of greater length than other turbomachine architectures, preferably greater than one times its diameter, which makes it more subject to the presence of ice. The invention applies, however, to a propeller 1 of any type of turbomachine, whether ducted or not.

[0053] Preferably, the wall 20 of the cone 2 has a thermal conductivity greater than 20 Wm-1.K-1, preferably greater than 150 Wm-1.K-1. According to one aspect, the wall 20 of the cone 2 is made of aluminum or graphene which has a high thermal conductivity to improve the heat transfer between the defrosting electrical switches 7A and the wall 20. This promotes the cooling of the defrosting electrical switches 7A and the defrosting of the cone 2.

[0054] Preferably also, as illustrated in the example of the, the cone 2 of the propeller 1 has an upstream part 14 and a downstream part 15, the upstream part 14 being removable from the downstream part 15. The cone 2 also has access openings 16 in the downstream part 15. As will be seen later, the removable upstream part 14 makes it easier to access the equipment mounted in the cone 2 during maintenance. The access openings 16 advantageously make it possible to disconnect the de-icing electrical switches 7A, 7B before removing the upstream part 14.

[0055] With reference to the, the electrical de-icing members 4 extend upstream of the blades 3, at the leading edge, which is the area most prone to the formation of frost. The electrical de-icing members 4 are integral with the wall 30 of the blades 3, namely in this example mounted on the internal face 31 of the wall 30 so as to be protected from external conditions and to preserve the aerodynamics of the blades 3. Alternatively, the electrical de-icing members 4 are mounted on the external face 32 of the wall 30 of the blades 3, for more effective de-icing. The electrical de-icing members 4 may also be integrated into the wall 30 of the blades 3 or even be mounted in a housing formed in the wall 30 of the blades 3.

[0056] As illustrated in the, preferably, in particular in the case of a turboprop propeller 1, electrical de-icing members 5 are also integral with the wall 20 of the cone 2 to ensure de-icing thereof. The electrical de-icing members 5 of the cone 2 preferably extend into the removable upstream part 14 which is most exposed to frost. As for the blades 3, the electrical de-icing members 5 of the cone are, in one aspect, mounted on the external face 22 of the wall 20 of the cone 2, as illustrated in the, or on the internal face 21, or are integrated into the wall 20 of the cone 2, or are mounted in a housing formed in the wall 20 of the cone 2.

[0057] The electrical defrosting members 4, 5 of the blades 3 and / or of the cone 2 are in a preferred aspect in the form of resistive heating elements, such as resistive heating mats. The resistive heating elements comprise electrical resistors which are configured, when electrically powered, to dissipate electrical power in the form of heat in the wall of the blades 3 and / or of the cone 2. The wall thus heated prevents the formation of frost and / or detaches the frost present from the wall.

[0058] Alternatively, the electrical de-icing members 4, 5 of the blades 3 and / or of the cone 2 are in the form of vibrating piezoelectric elements configured, when they are electrically powered, to deform mechanically and transmit mechanical stresses into the wall (vibrations), which prevents the formation of frost and / or separates the frost present from the wall.

[0059] The electrical de-icing members 4, 5 can be powered continuously or intermittently depending on the de-icing requirement and their positioning on the propeller. According to a preferred aspect, the electrical de-icing members 4 secured to the wall of the blades 3 and the electrical de-icing members 5 secured to the upstream tip of the cone 2 are powered intermittently. According to one aspect, the electrical de-icing members 5 mounted further downstream in the cone 2, for example at the downstream edge of the upstream portion 14, are powered continuously to prevent water runoff from the other de-iced portions upstream by evaporating said water runoff.

[0060] The electrical power supply is provided internally to the aircraft turbomachine, for example, by a permanent magnet alternator mounted in the accessory box, known to those skilled in the art under the designation "Accessory Gear Box (AGB)". From a torque taken from a rotating shaft of the turbomachine, the permanent magnet alternator produces a direct electric current. An inverter converts the direct electric current into alternating electric current which is transmitted by a rotating transformer to the control system 6 in the propeller 1. The rotating transformer comprises a rotor rotatably coupled to the propeller 1 and a stator mounted in a fixed part of the turbomachine, for example in the cavity delimited by the compressor casing. This aspect is known to those skilled in the art and is not described further.

[0061] With reference to the, the electrical power supplied to the electrical defrosting members 4, 5 is controlled by the control system 6, which is mounted in the rotating reference of the cone 2. The control system 6 comprises a control device 10 configured to distribute the electrical power dedicated to defrosting between the blades 3, as well as preferably the electrical power dedicated to controlling the pitch of the blades (not shown in the). The electrical switching device 10, such as an analog or digital electronic computer performing the temporal distribution of the power between the different heating parts, is preferably mounted along the longitudinal axis X to avoid generating an unbalance effect in the cone 2.

[0062] As described previously, the control system 6 also comprises a set of electrical switches 7A with a variable switching ratio controlled by the control device 10 depending in particular on the climatic conditions and the operating speed of the turbomachine. The electrical switches 7A are electrically connected to the control device 10 as well as to the electrical defrosting members 4, 5. The control device 10 is configured to provide an input electrical power Pe to the electrical switches 7A, which distribute an output electrical power Ps between the electrical defrosting members 4, 5. During their operation, the electrical switches 7A dissipate in the form of heat a dissipated electrical power Pd verifying: Pe = Ps + Pd.

[0063] Preferably, the 7A electrical switches are in the form of thyristors, field effect transistors, bipolar transistors and / or insulated gate bipolar transistors (IGBTs).

[0064] As described previously and illustrated in the, at least some of the electrical switches 7A of the control system 6, and preferably all of them, are mounted on the internal face 21 of the wall 20 of the cone 2 and called “defrosting electrical switches” in that they contribute to defrosting the cone 2. Indeed, their mounting makes it possible to transfer by thermal conduction the dissipated electrical power Pd that they emit in the form of heat during their operation.

[0065] According to a first embodiment of the invention illustrated in Figures 3 and 4, the electrical de-icing switches 7A are positioned in the removable upstream part 14 of the cone 2, upstream of the electrical de-icing members 5. The electrical de-icing switches 7A are distributed circumferentially on the wall 20 of the cone 2 so that their common center of inertia 8 belongs to the longitudinal axis X. This avoids an unbalance effect in the cone 2. The electrical de-icing switches 7A are aligned transversely with respect to the longitudinal axis X and are mounted on a portion of the wall 20 of the cone 2 forming a section 10A transverse with respect to the longitudinal axis X. The electrical de-icing switches 7A could alternatively extend in a staggered pattern in the section 10A.The 7A defrosting electrical switches are, for example, distributed circumferentially around the longitudinal axis X and radially symmetrically with respect to the longitudinal axis X.

[0066] Still with reference to Figures 3 and 4, the electrical defrosting members 5 are also aligned or arranged in a staggered manner transversely relative to the longitudinal axis X and are mounted on a portion of the wall 20 of the cone 2 forming a section 11 transverse to the longitudinal axis X. The section 11 of the electrical defrosting members 5 extends downstream of the section 10A of the electrical defrosting switches 7A. The longitudinal position of the section 11 of the electrical defrosting members 5 is hereinafter referred to as the “reference defrosting position Pref”.

[0067] In this example, both the electrical defrosting switches 7A and the electrical defrosting members 5 are mounted in the upstream portion 14 of the cone 2 and ensure defrosting thereof. The section 10 of the electrical defrosting switches 7A extends at the leading edge of the cone 2, where the incoming air flow is detached from the wall of the cone 2 and forms a stopping point. The section 11 of the electrical defrosting members 5 extends downstream of the upstream portion 14, where the incoming air flow is attached to the wall of the cone 2.

[0068] Alternatively, the section 10A could comprise a single de-icing electrical switch 7A mounted along the longitudinal axis X at the leading edge. The cone 2 could also be free of de-icing members 5 and the section 10A of de-icing electrical switches 7A could extend over all or part of the upstream part 14 of the cone 2, ensuring the de-icing of the cone 2 alone.

[0069] Illustrates a second embodiment of the invention, differing from the first in that the section 10B of defrosting electrical switches 7B extends downstream of the reference defrosting position Pref. In this example, the section 10B of defrosting electrical switches 7B extends in the downstream part 15 of the cone 2, preferably at the upstream edge of the downstream part 15. The defrosting electrical switches 7B alone ensure the defrosting of the downstream part 15 of the cone 2. The section 11 of defrosting electrical members 5 extends over all or part of the upstream part 14 of the cone 2 and alone ensures its defrosting.

[0070] Illustrates a third embodiment of the invention which is a combination of the embodiments of Figures 4 and 5. In this example, the cone 2 comprises an upstream section 10A and a downstream section 10B of defrosting electrical switches 7A, 7B extending respectively upstream and downstream of the reference defrosting position Pref. The upstream section 10A extends in the upstream part 14 while the downstream section 10B extends in the downstream part 15 of the cone 2.

[0071] According to a preferred aspect, the defrosting electrical switches 7A of the upstream section 10A are dedicated to the electrical supply of the defrosting electrical members 4, 5 ensuring continuous defrosting while those 7B of the downstream section 10B are dedicated to the electrical supply of the defrosting electrical members 4, 5 ensuring intermittent defrosting. The dissipated power Pd is thus greater at the upstream section 10A which is more exposed to frost.

[0072] In both embodiments of Figures 5 and 6, the cone 2 could be free of defrosting members 5 and the defrosting provided solely by the defrosting electrical switches 7A, 7B. In all the embodiments presented, the cone 2 could also comprise more than one section 10A, 10B of defrosting electrical switches 7A, 7B upstream and downstream of the reference defrosting position Pref.

[0073] According to a preferred aspect, in the example of figures 4, 5 and 6, access openings 16 are formed in the downstream part 15 of the cone 2. The access openings 16 advantageously make it possible to electrically disconnect the de-icing electrical switches 7A mounted in the upstream part 14 during maintenance, before disassembling the upstream part 14 from the downstream part 15 of the cone 2.

[0074] In all the embodiments presented, the electric defrosting switches 7A, 7B are preferably screwed to the wall 20 of the cone 2, so as to ensure good fixing and efficient heat transfer by conduction. As illustrated in FIGS. 8 and 9, each electric defrosting switch 7A, 7B comprises for this purpose a through opening 12 in which is inserted a fixing member 23 which is fixed to the wall 20, preferably at an excess thickness. The fixing member 23 is for example in the form of the assembly of a screw or a stud with a nut.

[0075] In the example of 1a, a through opening 24 is formed in the excess thickness of the wall 20 of the cone 2. The fixing member 23 is inserted from the outside into the through opening 12, 20 of the wall 20 and of the defrosting electrical switch 7A, 7B. In the example of 1a, a blind opening 25 is formed in the excess thickness of the wall 20, facing the internal face 21. The fixing member 23 is inserted from the inside into the through opening 12 of the defrosting electrical member 7A, 7B then into the blind opening 25 of the wall 20.

[0076] According to another preferred aspect illustrated in the and compatible with all the embodiments presented, one or more thermally conductive strips 9 are mounted on the internal face 21 of the wall 20 of the cone 2 in contact with an electrical defrosting switch 7A, 7B. The thermally conductive strips 9 preferably comprise aluminum, copper or graphene. This advantageously makes it possible to improve the thermal exchanges between the electrical defrosting switch 7A, 7B and the wall 20 of the cone 2.

[0077] According to a preferred aspect, a thermally conductive paste is arranged between the wall 20 of the cone 2 and the defrosting electrical switch 7A, 7B and / or the thermally conductive strip 9. This makes it possible to improve thermal exchanges and to fill any surface defects between the two elements.

[0078] A method of using the propeller 1 presented above is described below, implemented on the ground or during the flight of the aircraft in the presence of icing conditions or in a continuous preventive manner. The method of use consists of: from an input electrical power Pe, each electrical switch 7A, 7B of the control system 6 distributes an output electrical power Ps between the electrical members 4, 5 to de-ice the blades 3, and optionally the cone 2, and emits in the form of heat a dissipated electrical power Pd, The de-icing electrical switches 7A, 7B of the control system 6 transfer the dissipated electrical power Pd by thermal conduction in the wall 20 of the cone 2.

[0079] Thanks to their mounting against the wall 20 of the cone 2, the defrosting electrical switches 7A, 7B advantageously simultaneously ensure the cooling of the control system 6 and the defrosting of the cone 2.

Claims

Aircraft turbomachine propeller (1) comprising a cone (2) and a plurality of blades (3), the cone (2) extending along a longitudinal axis (X) oriented from upstream to downstream and being configured to be driven in rotation by a shaft of the aircraft turbomachine, the cone (2) comprising a wall (20) with an inner face (21) and an outer face (22), the propeller (1) comprising: a plurality of electrical de-icing members (4) secured to a wall (30) of the blades (3) in order to de-ice them, a control system (6) electrically connected to the electrical de-icing members (4) and comprising at least one electrical switch (7A, 7B) with a variable switching duty cycle configured, from an input electrical power (Pe), to distribute an output electrical power (Ps) to the electrical de-icing members (4) and to emit dissipated electrical power in the form of heat (Pd),the propeller (1) being characterized in that at least one electrical switch (7A, 7B) of the piloting system (6), called "electric de-icing switch (7A, 7B)", is mounted on the internal face (21) of the wall (20) of the cone (2) so as to transfer the dissipated electrical power (Pd) by thermal conduction in the wall (20) of the cone (2)., Propeller (1) according to claim 1, in which the de-icing electrical switch(es) (7A, 7B) have a global center of inertia (8) belonging to the longitudinal axis (X). Propeller (1) according to one of claims 1 and 2, in which the control system (6) comprises a plurality of electrical de-icing switches (7A, 7B), the electrical de-icing switches (7A, 7B) being arranged on at least one section (10A, 10B) of the cone (2) extending transversely relative to the longitudinal axis (X). Propeller (1) according to claim 3, comprising: a plurality of electrical de-icing members (5) secured to the wall (20) of the cone (2) and arranged on at least one section (11) of the cone (2) extending transversely relative to the longitudinal axis (X) and having a given longitudinal position (Pref) called “reference de-icing position (Pref)”, the electrical de-icing switches (7A, 7B) being arranged on a section (10A) called “upstream section (10A)” extending upstream of the reference de-icing position (Pref), or on a section (10B) called “downstream section (10B)” extending downstream of the reference de-icing position (Pref). Propeller (1) according to claim 3, comprising: a plurality of electrical de-icing members (5) secured to the wall (20) of the cone (2) and arranged on at least one section (11) of the cone (2) extending transversely relative to the longitudinal axis (X) and having a given longitudinal position (Pref) called “reference de-icing position (Pref)”, the electrical de-icing switches (7A, 7B) being arranged on a section (10A) called “upstream section (10A)” extending upstream of the reference de-icing position (Pref), and on a section (10B) called “downstream section (10B)” extending downstream of the reference de-icing position (Pref). Propeller (1) according to claim 5, in which: the electrical de-icing switches (7A) arranged on the upstream section (10A) are configured to intermittently electrically supply at least one electrical de-icing member (4, 5) and the electrical de-icing switches (7B) arranged on the downstream section (10B) are configured to continuously electrically supply at least one electrical de-icing member (4, 5). Propeller (1) according to one of claims 3 to 6, in which: the cone (2) comprises a downstream part (15) configured to be coupled in rotation to a shaft of the turbomachine and an upstream part (14) fixed in a removably manner on the downstream part (15), and at least one section (10A) extends in the upstream part (14) and / or at least one section (10B) extends in the downstream part (15). Propeller (1) according to claim 7, comprising at least one access opening (16) formed in the wall (20) of the cone (2) at the downstream part (15). Propeller (1) according to one of claims 1 to 8, in which the electrical de-icing members (4, 5) are in the form of resistive elements or piezoelectric elements. Method for deicing a propeller (1) of an aircraft turbomachine according to one of claims 1 to 9, in which: from an input electrical power (Pe), each electrical switch (7A, 7B) distributes an output electrical power (Ps) to the electrical deicing members (4, 5) to deice the blades (3) and emits in the form of heat a dissipated electrical power (Pd), said at least one deicing electrical switch (7A, 7B) transfers the dissipated electrical power (Pd) by thermal conduction into the wall (20) of the cone (2) to ensure the cooling of the control system (6) and the deicing of the wall (20) of the cone (2) simultaneously.

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