Aircraft turbomachine propeller and its de-icing process

Abstract

An aircraft turbomachine propeller (1) comprising a spinner (2) and a plurality of blades (3), the propeller (1) comprising a plurality of electrical de-icing devices (4) integral with a wall (30) of the blades (3) and a control system (6) electrically connected to the electrical de-icing devices (4) and comprising at least one electrical switch (7A) with a variable duty cycle configured, from an electrical input power (Pe), to distribute an electrical output power (Ps) to the electrical de-icing devices (4) and to emit 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 spinner (2) so as to transfer the dissipated electrical power (Pd) by thermal conduction in the wall (20) of the spinner (2). Abstract figure: Figure 3

Description

Title of the invention: Aircraft turbomachine propeller and its de-icing method. Technical field

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

[0002] In a known manner, an aircraft turbomachine includes a propeller upstream of the turbomachine's air inlet. 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 as a "Reduction Gear Box (RGB)".

[0003] During aircraft flight, ice is likely to form on the propeller. Ice accumulation is undesirable because it can alter the propeller's mass, its balance around the axis of rotation, and its aerodynamics. Furthermore, the detachment of an ice block from the propeller can lead to its ingestion 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 face at the leading edge and, in some cases, on the cone face. 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 then ejected from the turbomachine by the centrifugal force associated with the propeller's rotation.

[0005] It is known from French patent application FR3096080A1 to provide electrical power to the heating elements by means of a permanent magnet alternator mounted in the accessory gearbox, known to those skilled in the art as the "Accessory Gear Box (AGB)". From a torque taken from a rotating shaft of the turbomachine, the permanent magnet alternator produces a direct current. An inverter converts the direct current into alternating 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 housing.

[0006] To ensure effective de-icing without 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 takes the form of a power electronics component, for example, a transistor (IGBT, etc.). The switch assembly has an adjustable duty cycle, depending in particular on climatic conditions and the operating mode of the turbomachine. The switch assembly must be mounted between the rotating transformer and the heating elements to limit the number of rotating transformers to a single one for all the heating elements. This requires positioning the switch assembly within the cavity defined by the cone, centered on the cone's rotational axis, to avoid an unbalanced effect.

[0007] In practice, the switch assembly dissipates some of the electrical power transmitted by the rotating transformer as heat, potentially amounting to a few percent. Such heating of a power electronics component is undesirable and necessitates the integration of a ventilation device within the cone, which increases the onboard mass, complexity, and cost.

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

[0009] Furthermore, climate change is a major concern for many legislative and regulatory bodies worldwide. 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 types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively contributing to the fight against climate change for several years now.

[0010] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0011] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0012] 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 onboard equipment, the development of the use of electrical technologies for propulsion, and, essential complementary to technological progress, aviation biofuels.

[0013] 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

[0014] The invention relates to an aircraft turbomachine propeller comprising a cone and a plurality of blades, the cone extending along a longitudinal axis oriented upstream to downstream and being configured to be driven in rotation by a shaft of the aircraft turbomachine, the cone comprising a wall having an inner face and an outer face, the propeller comprising: • a plurality of electrical de-icing devices attached to a wall of the blades in order to de-ice them, • a control system electrically connected to the electrical defrosting devices and comprising at least one electrical switch with variable duty cycle configured, from an electrical input power, to distribute an electrical output power to the electrical defrosting devices and to emit dissipated electrical power in the form of heat.

[0015] The invention is remarkable in that at least one electrical switch of the control system, called "electric defrosting switch", is mounted on the inner face of the cone wall so as to transfer the electrical power dissipated by thermal conduction into the cone wall.

[0016] The invention advantageously facilitates the cooling of the control electronics mounted in the propeller cone to ensure blade de-icing. Mounting the electrical switches on the cone wall allows the electrical power dissipated as heat by the switches to be transferred to 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 required within the cone. Furthermore, this positioning of the electrical switches advantageously contributes directly to the de-icing of the propeller cone, as the electrical power dissipated as heat by the switches warms the cone wall by thermal conduction.

[0017] According to one aspect of the invention, the defrosting electric switch(s) have an overall center of inertia located on the longitudinal axis. This avoids an imbalance effect in the cone.

[0018] According to one aspect of the invention, the control system comprises a plurality of defrosting electric switches, the defrosting electric switches being arranged on at least one section of the cone extending transversely with respect to the longitudinal axis. The defrosting electric switches are advantageously arranged longitudinally with respect to the cone according to the defrosting requirement, which depends on the flow conditions of the incoming airflow.

[0019] According to a first aspect of the invention, the propeller comprises: • a plurality of electrical de-icing devices attached to the cone wall and arranged on at least one section of the cone extending transversely with respect to the longitudinal axis and having a given longitudinal position called the "reference de-icing position", • the defrosting electrical switches being arranged on a section called the "upstream section" extending upstream of the reference defrosting position or on a section called the "downstream section" extending downstream of the reference defrosting position.

[0020] The electrical defrosting devices thus ensure defrosting in the area most prone to frost, where the incoming airflow is attached to the wall. The upstream electrical defrosting switches ensure defrosting of the leading edge of the cone, where the airflow is detached from the wall, and where the need for defrosting is less. The need for defrosting is also less further downstream of the cone.

[0021] According to a second aspect of the invention, the propeller comprises: • a plurality of electrical de-icing devices mounted as a fixed unit to the cone wall and arranged on at least one section of the cone extending transversely with respect to the longitudinal axis and having a given longitudinal position called the "reference de-icing position", • the defrosting electrical switches being arranged on a section called the "upstream section" extending upstream of the reference defrosting position, and on a section called the "downstream section" extending downstream of the reference defrosting position.

[0022] Such an architecture advantageously allows for significant de-icing of the cone over a large portion. The cooling of the steering system is also improved.

[0023] According to one aspect of the invention: • The de-icing electrical switches located on the upstream section are configured to intermittently supply electrical power to at least one de-icing electrical device, and • The de-icing electrical switches located on the downstream section are configured to continuously supply electrical power to at least one de-icing electrical device.

[0024] The de-icing electrical switches of the upstream section thus dissipate more electrical power is converted into heat at the downstream section, allowing for better defrosting of the upstream section, which is more exposed to frost. The de-icing electrical switches in the downstream section thus dissipate power continuously, preventing water runoff from the upstream section from refreezing, and potentially allowing it to evaporate, preventing any risk of ice formation downstream of the downstream section.

[0025] According to one aspect of the invention: • The cone comprises a downstream part configured to be rotationally coupled to a shaft of the turbomachine and an upstream part detachably fixed to the downstream part. • at least one section extends into the upstream part and / or at least one section extends into the downstream part.

[0026] Such an architecture advantageously allows for easy maintenance of electrical equipment mounted in the cone.

[0027] According to one aspect of the invention, the propeller comprises a plurality of access openings formed in the cone wall at the downstream end. This allows the de-icing electrical switches to be disconnected before the upstream part of the cone is disassembled during maintenance.

[0028] According to one aspect of the invention, the electrical defrosting devices are in the form of resistive elements or piezoelectric elements.

[0029] 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.

[0030] According to a preferred aspect of the invention, the cone wall has a thermal conductivity greater than 20 Wm-1K-1, preferably greater than 150 Wm-1K-1, and preferably comprises aluminum or graphene. This promotes heat exchange between the cone wall and the defrosting electrical switches.

[0031] According to a preferred aspect, said at least one defrosting electrical switch is screwed to the cone wall, preferably at a point where the cone wall is thickened. This promotes heat exchange by conduction between the cone wall and the defrosting electrical switches.

[0032] According to a preferred aspect, the propeller comprises at least one thermally conductive strip mounted on the inner face of the cone in contact with at least one de-icing electrical switch. This promotes heat exchange by conduction between the cone wall and the de-icing electrical switches.

[0033] The invention also relates to a method for de-icing an aircraft turbomachine propeller as described above, in which: • from an electrical input power, each electrical switch distributes electrical output power to the electrical defrosting components to defrost the blades and emits dissipated electrical power in the form of heat. • said at least one defrosting electrical switch transfers the electrical power dissipated by thermal conduction into the cone wall to ensure the cooling of the pilot system and the defrosting of the cone wall simultaneously.

[0034] The invention also relates to a method for maintaining an aircraft turbine propeller, consisting of: • Disconnect said at least one defrosting electrical switch via said at least one access opening, then • Disassemble the front part of the cone from the downstream part of the cone.

[0035] 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 fixed in the aircraft turbomachine, the rotating transformer being configured to transmit an alternating electric current to the propeller steering system.

[0036] The aircraft turbomachine is in the form of a turboprop. PRESENTATION OF THE FIGURES

[0037] 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.

[0038] Fig. 1 is a schematic perspective representation of an aircraft turbomachine propeller according to one embodiment of the invention.

[0039] Fig. 2 is a schematic perspective representation of an aircraft turbomachine propeller according to another embodiment of the invention.

[0040] The [Fig.3] is a schematic representation in longitudinal half-section of the propeller according to a first embodiment of the invention.

[0041] Fig. 4 is a schematic cross-sectional representation of the defrosting electric switches of Fig. 3.

[0042] The [Fig.5] is a schematic representation in longitudinal half-section of the propeller according to a second embodiment of the invention.

[0043] The [Fig.6] is a schematic representation in longitudinal half-section of the propeller according to a third embodiment of the invention.

[0044] Figure 7 is a schematic front view representation of a defrosting electric switch mounted on the cone wall with thermally conductive elements. only according to one embodiment of the invention.

[0045] Fig. 8 and Fig. 9 are two schematic profile views of the assembly of an electric defrosting switch according to two alternative embodiments of the invention.

[0046] It should be noted that the figures explain the invention in detail to put into works the invention, the said figures being of course able to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0047] With reference to Figures 1 and 3, the invention relates to an aircraft turbomachine propeller 1 comprising: a cone 2 extending along a longitudinal axis X oriented 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 to the inner face 21, blades 3, electrical de-icing devices 4 attached 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 devices 4 and comprising one or more electrical switches 7A of variable switching duty ratio configured, from an electrical input power Pe, to distribute an electrical output power Ps to the electrical de-icing devices 4 and to emit in the form of heat a dissipated electrical power Pd.

[0048] According to the invention and as illustrated in Figures 1 and 3, one or more electrical switches 7A of the control system 6, referred to as "defrosting electrical switches", are mounted on the inner 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.

[0049] The invention advantageously facilitates the cooling of the control electronics mounted in the propeller cone to ensure the de-icing of the blades 3. Mounting the electrical switches 7A on the cone wall 2 allows the electrical power dissipated as heat by the electrical switches 7A to be transferred to the cone wall 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 required in the cone 2. Such positioning of the In addition, electrical switches advantageously contribute directly to the de-icing of cone 2 of the propeller, because the electrical power dissipated as heat by the electrical switches warms the wall of cone 2 by thermal conduction.

[0050] With reference to [Fig. 1], the propeller 1 is mounted to rotate about 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 as a "Reduction Gear Box (RGB)". Upstream and downstream are defined with respect 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 with respect to that of the longitudinal axis X.

[0051] The invention offers a particular advantage in the case of a turboprop propeller 1, which has a cone 2 of greater length than other turbomachine designs, preferably more than its diameter, making it more susceptible to icing. However, the invention applies to a propeller 1 of any type of turbomachine, whether shrouded or not.

[0052] Preferably, the wall 20 of the cone 2 has a thermal conductivity greater than 20 Wm-1K-1, preferably greater than 150 Wm-1K-1. According to one aspect, the wall 20 of the cone 2 is made of aluminum or graphene, which has high thermal conductivity to improve 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.

[0053] Preferably, as illustrated in the example in [Fig. 2], the cone 2 of the propeller 1 has an upstream portion 14 and a downstream portion 15, the upstream portion 14 being removable from the downstream portion 15. The cone 2 also has access openings 16 in the downstream portion 15. As will be seen later, the removable upstream portion 14 facilitates access to the equipment mounted in the cone 2 during maintenance. The access openings 16 advantageously allow the de-icing electrical switches 7A, 7B to be disconnected before removing the upstream portion 14.

[0054] With reference to [Fig. 3], the electric de-icing devices 4 extend upstream of the blades 3, at the leading edge, which is the area most prone to ice formation. The electric de-icing devices 4 are integral with the wall 30 of the blades 3, namely, in this example, mounted on the inner 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 electric de-icing devices 4 are mounted on the outer face 32 of the wall 30 of the blades 3, for more efficient de-icing. The electric de-icing devices 4 can also be integrated into the wall 30 of the blades 3 or even to be mounted in a housing formed in the wall 30 of the blades 3.

[0055] As illustrated in [Fig. 3], preferably, particularly in the case of a turboprop propeller 1, electrical de-icing devices 5 are also attached to the wall 20 of the cone 2 to ensure its de-icing. The electrical de-icing devices 5 of the cone 2 preferably extend into the removable upstream portion 14, which is most exposed to frost. As with the blades 3, the electrical de-icing devices 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 [Fig. 3], 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.

[0056] The electrical defrosting elements 4, 5 of the blades 3 and / or the cone 2 are preferably in the form of resistive heating elements, such as resistive heating mats. These resistive heating elements comprise electrical resistors which, when electrically powered, are configured to dissipate electrical power as heat in the wall of the blades 3 and / or the cone 2. The heated wall thus prevents the formation of frost and / or detaches any existing frost from the wall.

[0057] Alternatively, the electrical de-icing devices 4, 5 of the blades 3 and / or of the cone 2 are in the form of vibrating piezoelectric elements configured, when electrically powered, to deform mechanically and transmit mechanical stresses in the wall (vibrations), which prevents the formation of frost and / or detaches the existing frost from the wall.

[0058] The electric de-icing devices 4, 5 can be powered continuously or intermittently depending on the de-icing requirement and their positioning on the propeller. In a preferred embodiment, the electric de-icing devices 4 attached to the blade wall 3 and the electric de-icing devices 5 attached to the upstream tip of the cone 2 are powered intermittently. In another embodiment, the electric de-icing devices 5 mounted further downstream in the cone 2, for example at the downstream edge of the upstream section 14, are powered continuously to prevent water runoff from the other upstream de-iced sections by evaporating said water runoff.

[0059] The electrical supply is provided internally within the aircraft turbomachine, for example, by a permanent magnet alternator mounted in the accessory gearbox, known to those skilled in the art as the "Accessory Gear Box (AGB)". From a torque taken from a rotating shaft of the turbomachine, the permanent magnet alternator produces a direct current. An inverter converts the direct current into alternating current, which is transmitted by a rotating transformer to the steering system 6 in the propeller 1. The trans The rotating former comprises a rotor coupled in rotation to the propeller 1 and a stator mounted in a fixed part of the turbomachine, for example in the cavity delimited by the compressor housing. This aspect is known to those skilled in the art and is not described further.

[0060] With reference to [Fig. 3], the electrical power supplied to the defrosting electrical components 4, 5 is controlled by the control system 6, which is mounted in the rotating frame of the cone 2. The control system 6 includes a control device 10 configured to distribute the electrical power dedicated to defrosting between the blades 3, and preferably also the electrical power dedicated to controlling the blade pitch (not shown in [Fig. 3]). The electrical switching device 10, such as an analog or digital electronic computer performing the temporal distribution of power between the different heating parts, is preferably mounted along the longitudinal axis X to avoid generating an imbalance effect in the cone 2.

[0061] As described previously, the control system 6 also includes 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 regime of the turbomachine. The electrical switches 7A are electrically connected to the control device 10 as well as to the electrical de-icing elements 4, 5. The control device 10 is configured to supply an electrical input power Pe to the electrical switches 7A, which distribute an electrical output power Ps between the electrical de-icing elements 4, 5. During their operation, the electrical switches 7A dissipate an electrical power Pd in ​​the form of heat, satisfying: Pe = Ps + Pd.

[0062] Preferably, the 7A electrical switches are in the form of thyristors, field-effect transistors, bipolar transistors and / or insulated-gate bipolar transistors (IGBTs).

[0063] As described previously and illustrated in [Fig.3], at least some of the electrical switches 7A of the control system 6, and preferably all of them, are mounted on the inner face 21 of the wall 20 of the cone 2 and are called "de-icing electrical switches" because they help to de-ice the cone 2. Indeed, their mounting allows the dissipated electrical power Pd that they emit as heat during their operation to be transferred by thermal conduction.

[0064] According to a first embodiment of the invention illustrated in Figures 3 and 4, the defrosting electrical switches 7A are positioned in the removable upstream portion 14 of the cone 2, upstream of the defrosting electrical components 5. The defrosting electrical switches 7A are distributed circumferentially on the wall 20 of the cone 2 such that their common center of inertia 8 lies on the longitudinal axis X. This avoids an imbalance effect in the cone 2. The defrosting electrical 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 defrosting electrical switches 7A could alternatively extend in a staggered fashion in the section 10A. The defrosting electric switches 7A are, for example, distributed circumferentially around the longitudinal axis X and radially symmetrically with respect to the longitudinal axis X.

[0065] Also with reference to Figures 3 and 4, the defrosting electric elements 5 are also aligned or staggered 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 11 transverse with respect to the longitudinal axis X. The section 11 of the defrosting electric elements 5 extends downstream of the section 10A of the defrosting electric switches 7A.The longitudinal position of section 11 of the electrical defrosting components 5 is hereinafter referred to as the "reference defrosting position Pref".

[0066] In this example, both the de-icing electrical switches 7A and the de-icing electrical devices 5 are mounted in the upstream portion 14 of the cone 2 and ensure its de-icing. The section 10 of the de-icing electrical switches 7A extends to the leading edge of the cone 2, where the incoming airflow is separated from the wall of the cone 2 and forms a stagnation point. The section 11 of the de-icing electrical devices 5 extends downstream of the upstream portion 14, where the incoming airflow is attached to the wall of the cone 2.

[0067] Alternatively, section 10A could include a single de-icing electric switch 7A mounted along the longitudinal axis X at the leading edge. Cone 2 could also be free of de-icing devices 5, and section 10A of de-icing electric switches 7A could extend over all or part of the upstream portion 14 of cone 2, thus providing de-icing for cone 2 alone.

[0068] Figure 5 illustrates a second embodiment of the invention, differing from the first in that the section 10B of the defrosting electrical switches 7B extends downstream of the reference defrosting position Pref. In this example, the section 10B of the defrosting electrical switches 7B extends into 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 the defrosting electrical components 5, on the other hand, extends over all or part of the upstream part 14 of the cone 2 and alone ensures its defrosting.

[0069] Figure 6 illustrates a third embodiment of the invention, which is a combination of the embodiments shown in 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 into the upstream portion 14 while the downstream section 10B extends into the downstream part 15 of cone 2.

[0070] According to a preferred design, the defrosting electrical switches 7A in the upstream section 10A are dedicated to supplying power to the defrosting electrical devices 4, 5, ensuring continuous defrosting, while those 7B in the downstream section 10B are dedicated to supplying power to the defrosting electrical devices 4, 5, ensuring intermittent defrosting. The power dissipated Pd is thus greater in the upstream section 10A, which is more exposed to frost.

[0071] In both embodiments of Figures 5 and 6, the cone 2 could be free of defrosting elements 5 and defrosting would be provided solely by the defrosting electrical switches 7A, 7B. In all embodiments shown, the cone 2 could also include more than one section 10A, 10B of defrosting electrical switches 7A, 7B upstream and downstream of the reference defrosting position Pref.

[0072] 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 allow the electrical disconnection of the defrosting 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.

[0073] In all the embodiments shown, the defrosting electric switches 7A, 7B are preferably screwed to the wall 20 of the cone 2, so as to ensure secure fastening and efficient heat transfer by conduction. As illustrated in Figures 8 and 9, each defrosting electric switch 7A, 7B comprises for this purpose a through opening 12 into which a fastening element 23 is inserted, which is fixed to the wall 20, preferably at a raised section. The fastening element 23 is, for example, in the form of a screw or stud with a nut.

[0074] In the example of [Fig. 8], a through-hole 24 is formed in the thickness of the wall 20 of the cone 2. The fastening member 23 is inserted externally into the through-hole 12, 20 of the wall 20 and of the defrosting electrical switch 7A, 7B. In the example of [Fig. 9], a blind opening 25 is formed in the thickness of the wall 20, facing the inner face 21. The fastening member 23 is inserted internally into the through-hole 12 of the defrosting electrical device 7A, 7B and then into the blind opening 25 of the wall 20.

[0075] According to another preferred aspect illustrated in [Fig. 7] and compatible with all the embodiments shown, one or more thermally conductive strips 9 are mounted on the inner face 21 of the wall 20 of the cone 2 in contact with a defrosting electrical switch 7A, 7B. The thermally conductive strips 9 preferably comprise aluminum, copper, or graphene. This allows advantageously improve the heat exchange between the defrosting electric switch 7 A, 7B and the wall 20 of cone 2.

[0076] According to a preferred aspect, a thermally conductive paste is disposed between the wall 20 of the cone 2 and the defrosting electrical switch 7A, 7B and / or the thermally conductive strip 9. This improves heat exchange and fills any surface defects between the two elements.

[0077] A method for using the propeller 1 described above, implemented on the ground or during aircraft flight in the presence of icing conditions or on a continuous preventive basis, is described below. The method of use consists of: • from an electrical input power Pe, each electrical switch 7A, 7B of the control system 6 distributes an electrical output power Ps between the electrical components 4, 5 to defrost the blades 3, and optionally the cone 2, and emits in the form of heat a dissipated electrical power Pd, • The defrosting electrical switches 7A, 7B of the control system 6 transfer the dissipated electrical power Pd by thermal conduction into the wall 20 of the cone 2.

[0078] Thanks to their mounting against the wall 20 of the cone 2, the defrosting electrical switches 7A, 7B advantageously ensure simultaneously the cooling of the control system 6 and the defrosting of the cone 2.

Claims

Demands

1. An aircraft turbomachine propeller (1) comprising a spinner (2) and a plurality of blades (3), the spinner (2) extending along a longitudinal axis (X) oriented upstream to downstream and configured to be driven in rotation by a shaft of the aircraft turbomachine, the spinner (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 devices (4) fixed to a wall (30) of the blades (3) for de-icing them, • a control system (6) electrically connected to the electrical de-icing devices (4) and comprising at least one electrical switch (7A, 7B) with a variable duty cycle configured, from an electrical input power (Pe), to distribute an electrical output power (Ps) to the electrical de-icing devices (4) and to emit electrical power in the form of heat dissipated (Pd),• the propeller (1) being characterized in that at least one electrical switch (7A, 7B) of the piloting system (6), called the "de-icing electrical switch (7A, 7B)", is mounted on the inner face (21) of the 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).

2. Propeller (1) according to claim 1, wherein the defrosting electric switch(s) (7A, 7B) have an overall center of inertia (8) belonging to the longitudinal axis (X).

3. Propeller (1) according to any one of claims 1 and 2, wherein the piloting system (6) comprises a plurality of electric de-icing switches (7A, 7B), the electric de-icing switches (7A, 7B) being arranged on at least one segment (10A, 10B) of the cone (2) extending transversely with respect to the longitudinal axis (X).

4. Propeller (1) according to claim 3, comprising: • a plurality of electrical de-icing elements (5) integral with the wall (20) of the cone (2) and arranged on at least one section (11) of the cone (2) extending transversely by relative to the longitudinal axis (X) and having a given longitudinal position (Pref) called "reference defrosting position (Pref)", the defrosting electrical switches (7A, 7B) being arranged on a section (10A) called "upstream section (10A)" extending upstream of the reference defrosting position (Pref), or on a section (10B) called "downstream section (10B)" extending downstream of the reference defrosting position (Pref).

5. Propeller (1) according to claim 3, comprising: • a plurality of electrical defrosting elements (5) attached to the wall (20) of the cone (2) and arranged on at least one section (11) of the cone (2) extending transversely with respect to the longitudinal axis (X) and having a given longitudinal position (Pref) referred to as the "reference defrosting position (Pref)", • the electrical defrosting switches (7A, 7B) being arranged on a section (10A) referred to as the "upstream section (10A)" extending upstream of the reference defrosting position (Pref), and on a section (10B) referred to as the "downstream section (10B)" extending downstream of the reference defrosting position (Pref).

6. Propeller (1) according to claim 5, wherein: • the defrosting electrical switches (7A) arranged on the upstream section (10A) are configured to intermittently supply electrical power to at least one defrosting electrical device (4, 5) and • the defrosting electrical switches (7B) arranged on the downstream section (10B) are configured to continuously supply electrical power to at least one defrosting electrical device (4, 5).

7. Propeller (1) according to any one of claims 3 to 6, wherein: • the cone (2) comprises a downstream portion (15) configured to be rotationally coupled to a shaft of the turbomachine and an upstream portion (14) detachably fixed to the downstream portion (15), and • at least one section (10A) extends into the upstream part (14) and / or at least one section (10B) extends into the downstream part (15).

8. Propeller (1) according to claim 7, comprising at least one access opening (16) formed in the wall (20) of the cone (2) at the level of the downstream part (15).

9. Propeller (1) according to any one of claims 1 to 8, wherein the electrical defrosting elements (4, 5) are in the form of resistive or piezoelectric elements.

10. A method for de-icing an aircraft turbomachine propeller (1) according to any one of claims 1 to 9, wherein: • from an input electrical power (Pe), each electrical switch (7A, 7B) distributes an output electrical power (Ps) to the electrical de-icing devices (4, 5) to de-ice the blades (3) and emits dissipated electrical power (Pd) in the form of heat, • said at least one de-icing 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 steering system (6) and the de-icing of the wall (20) of the cone (2) simultaneously.

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