ENERGY CONVERSION DEVICE

Description

[0001] The present invention relates to energy conversion devices, particularly generator devices for converting mechanical energy supplied by a motor into electrical energy. More specifically, the invention relates to the cooling of such electrical machines. An energy conversion device with cooling is described in document DE102015223073A1.

[0002] The invention's field of application is the generation of electrical energy from mechanical energy supplied by an aircraft engine turbine. This energy is used, for example, to power an aircraft's onboard electrical system. However, the invention is also applicable to other types of engines, such as industrial turbines or auxiliary power unit (APU) turbines.

[0003] Historically, aircraft electrical systems operated at a fixed frequency of 400 Hz. Since not all aircraft engines operate at a constant speed, this type of generator was driven by the engines via a mechanical speed governor. This speed governor allowed a variable-speed input shaft to produce a fixed-speed output. With the advent of variable-frequency electrical systems, aircraft generators now operate over a wide speed range, typically with a 1:2 ratio.

[0004] The invention is particularly applicable to generator devices intended to operate over a variable speed range to enable the delivery of electrical energy of variable frequency when the generator device generates electrical energy.

[0005] The generator device is, for example, the main electric machine of a brushless synchronous starter-generator. The main machine comprises a rotor module including an inductor and a stator module including an armature.

[0006] A main electrical machine of this type is conventionally oil-cooled, as schematically represented in figure 1 The generator device includes an oil circulation circuit for generating an oil mist in a housing 106 radially surrounding a hollow shaft 102, the rotor module 101, and the stator module 103, in order to cool the rotor module 101 and the stator module 103. The rotor module 101 is integral with the hollow shaft 102 and mounted to rotate relative to the stator 103 and a housing 104. The housing 104 also defines a reservoir 107 into which the oil falls by gravity after forming the oil mist. The oil circulation circuit includes a pump, not visible in the illustration. figure 1 This allows oil to be drawn from reservoir 107 and injected, in the direction of the arrow, into an internal volume 109 of the hollow shaft 102, delimited by a body 110 of the hollow shaft. The hollow shaft 102 includes nozzles g1, g2, g3, g4 formed in the body 110 of the hollow shaft, ensuring fluid communication between the internal volume 109 of the hollow shaft 102 and the enclosure 106. These nozzles are configured to create an oil mist in the enclosure 106 from the oil injected into the internal volume 109 of the hollow shaft 102 during the rotation of the shaft 102. The pump is conventionally a rotary positive displacement pump, mechanically coupled to the hollow shaft 102, which rotates around the longitudinal axis of the hollow shaft 108.

[0007] When the generator device operates at variable speed, the oil flow rate delivered by this type of pump is proportional to its rotational speed. Thus, the oil flow rate injected by the pump into the internal volume 109 of the hollow shaft 102 increases as the rotational speed of the hollow shaft 102 increases, which in turn increases the oil flow rate injected into the chamber and therefore the density of the oil mist present in the chamber 106.

[0008] At low speeds, when delivering low-frequency current, the oil flow rate must be sufficient to ensure proper cooling of the rotor and stator modules of the main electrical machine. At high speeds, when delivering high-frequency current, the flow rate is generally much higher than required.

[0009] Furthermore, the mechanical losses associated with the rotation of the main electric machine's rotating parts in the oil mist inherently increase with rotational speed. When, in addition, the oil flow rate within the enclosure increases with speed, the density of the oil mist also increases with speed, further exacerbating the effect of increased speed on mechanical losses. These mechanical losses then significantly reduce the efficiency of the electric machine. The increased mist density can also lead to oil splashing of the main electric machine, which can prevent its operation, particularly when the main electric machine is tilted, i.e., when its shaft is inclined relative to a horizontal plane (when the aircraft's attitude is not zero).

[0010] One solution to mitigate these problems is to reduce the diameter of the active parts (rotor and stator modules) of the electric machine. The drawback of this solution is an increase in the cantilever moment and mass of the electric machine. Indeed, the machine is designed to have a minimum mass. The electromagnetic design is carried out to achieve this minimum mass and determines, among other parameters, the optimal dimensions of the machine, namely its diameter and length. Reducing the diameter of the active parts deviates from this optimal solution, leading to an increase in the mass of the electric machine.

[0011] A second solution is to limit the oil flow to a minimum, with the disadvantage of less effective cooling at low speeds.

[0012] These two solutions do not allow the regulation of the flow rate according to the speed, but allow the generator device to be adapted to an increase in the rotation speed of the hollow shaft at the cost of an impact on its performance (higher mass and / or heating).

[0013] A third solution represented in figure 2 , consists of introducing, in the oil circulation circuit, a regulating valve 112, to limit the increase in the flow of oil sprayed into the enclosure with the increase in speed. This regulating valve 112 draws a portion of the oil delivered by the pump 108, after cooling by a heat exchanger E and before its injection into the chamber 106, and sends it directly to the reservoir 107. More precisely, the oil drawn by the regulating valve 112 at the outlet of the pump 108 is injected into the reservoir 107 without passing through the nozzles g1 to g4. This limits the flow rate of oil injected into the chamber 106, i.e., the density of the oil mist in the cavity 106. The valve 112 is adjusted to limit the increase in the flow rate of oil injected into the chamber 106 via the nozzles g1 to g4 due to an increase in the rotational speed of the hollow shaft 102, or to maintain this flow rate constant.

[0014] This third solution, however, presents several drawbacks. It relies on the introduction of an additional component, the valve, which leads to higher manufacturing costs and reduces the reliability of the generator. Indeed, the valve can be susceptible to oil contamination by particles that could block it and thus reduce the flow rate at low speeds. Furthermore, the valve is generally based on a piston-and-spring system that, depending on its time constant, can cause resonances in the oil circuit due to variations in flow rate and pressure, for example, when the pump outlet pressure is pulsating. In addition, the maximum stroke of the valve piston limits its ability to regulate the oil flow. Once the valve is fully open, the oil flow is no longer regulated.Furthermore, since the valve operates based on the inlet pressure, the inlet pressure will still increase with speed. Therefore, even if the valve reduces the increase in oil flow through cavity 106 via nozzles g1 to g4, this flow rate will inevitably still increase with speed. This solution necessitates the use of a high-performance heat exchanger to dissipate energy losses at high speeds. Moreover, more power must be drawn from the turbine, which reduces the efficiency of the electric machine.

[0015] A fourth solution involves driving the pump by a means other than the electric machine's shaft, for example, by a dedicated pump motor. This allows the oil flow rate delivered by the pump to be adjusted independently of the electric machine's shaft speed. This solution has obvious drawbacks in terms of complicating the oil circulation circuit architecture: the addition of a motor, motor control, and extra cables for its operation significantly impacts the mass, cost, and reliability of the generator.

[0016] One aim of the invention is to limit at least one of the aforementioned disadvantages.

[0017] To this end, the invention relates to an energy conversion device capable of producing electricity from mechanical energy and / or vice versa, the energy conversion device comprising: a housing, a shaft comprising a body defining an internal volume, the shaft being intended to rotate in a predetermined direction about a longitudinal axis relative to the housing over a predetermined rotational speed range, a rotor module integral with the shaft, a stator module integral with the housing, the rotor module and the stator module comprising an inductor and an armature magnetically coupled to each other, the housing delimiting an internal volume housing the rotor module and the stator module and comprising a cavity surrounding the rotor module and the stator module, an assembly of at least one nozzle passing through the body and ensuring fluidic communication between the internal volume and the cavity, the assembly of at least one nozzle being configured to form an oil mist in the cavity under the effect of the rotation of the shaft within the rotational speed range, from a portion of oil injected into the internal volume of the hollow shaft,Since the oil mist is intended to come into direct physical contact with the rotor module and the stator module, an assembly of at least one control circuit configured to limit an increase in the oil flow rate passing from the internal volume to the cavity through the assembly of at least one nozzle, said increase being due to an increase in the oil flow rate injected into the internal volume, the control circuit comprising: a conduit integral with the shaft and including an inlet communicating with the internal volume so as to receive, under the effect of the rotation of the shaft, another part of the oil injected into the internal volume, the conduit carrying the other part of the oil to an outlet of the conduit, a discharge device configured to discharge at least a part of the oil exiting the conduit into an oil reservoir, without contributing to the oil mist.

[0018] Advantageously, the conduit receives, under the effect of centrifugal force, the other part of the oil injected into the internal volume, the conduit leading the other part of the oil to an outlet of the conduit,

[0019] Advantageously, the device includes an oil circulation pump configured to draw oil from the oil reservoir and inject it into the internal volume of the shaft, the pump being mechanically coupled to the shaft so as to be driven in rotation by the shaft so that the flow of oil injected by the pump into the internal volume increases with an increase in the speed of rotation of the shaft in the direction of rotation.

[0020] Advantageously, the conduit includes a main conduit surrounded radially by the stator module and configured to conduct the oil it receives, during rotation of the shaft, in translation relative to the shaft along the longitudinal axis and / or in rotation relative to the shaft body around the longitudinal axis, around the internal volume.

[0021] Advantageously, the main conduit of the control circuit is provided in the shaft body and is closed by the rotor module.

[0022] Advantageously, the main conduit of a control circuit is helically wound around the longitudinal axis and configured to draw oil into the main conduit during shaft rotation.

[0023] Advantageously, the geometric characteristics of the conduit are defined so that the conduit carries all or part of an excess of the oil flow injected by the pump into the internal volume, beyond a minimum flow, over the entire range of rotational speed.

[0024] Advantageously, the evacuation device includes a collection hood disposed in the cavity and fixed relative to the casing, the collection hood radially surrounding an outlet of the conduit so as to collect at least a part of the oil exiting the conduit under the effect of centrifugal force, during the rotation of the shaft in the direction of rotation.

[0025] Advantageously, the drainage system includes a drainage opening located opposite the oil reservoir, allowing the oil collected by the hood to be evacuated by gravity to the oil reservoir.

[0026] Advantageously, the collection hood includes a ring completely surrounding the outlet radially and configured to retain radially and axially in both directions the oil exiting the conduit, an opening being provided in the ring opposite the oil reservoir.

[0027] Advantageously, the collection ring is equipped with a drain pipe having an inlet surrounding the opening and extending to the drain opening.

[0028] Advantageously, the conduit is configured to limit an increase in the oil flow rate, passing from the internal volume to the cavity through the assembly of at least one nozzle, said increase being due to an increase in the oil flow rate injected into the internal volume.

[0029] Other features, details and advantages of the invention will become apparent from the description provided with reference to the accompanying drawings given by way of example, which represent, respectively: [ Fig.1 ] there figure 1 , already described, schematically represents in cross-section, along a radial plane, a rotating machine of the prior art, [ Fig.2 ] there figure 2 already described schematically represents an oil circulation circuit of a prior art energy transformation device, [ Fig.3 ] there figure 3 schematically represents an oil circulation circuit of an energy transformation device according to the invention, [ Fig.4 ] there figure 4 schematically represents, in cross-section along a first radial plane, an example of a rotating electrical machine according to the invention, [ Fig.5 ] there figure 5 schematically represents, in cross-section along a second radial plane, the rotating machine of the figure 4 , [ Fig.6 ] there figure 6 schematically represents, in thick line, an oil flow D1(v) exiting the set of nozzles as a function of the angular speed v of the shaft in the absence of an oil regulation device and, in thin line, an example of oil flow D2(v) exiting the set of nozzles as a function of the angular speed v of the shaft in the presence of the oil regulation device.

[0030] From one figure to another, the same elements are identified by the same references.

[0031] The invention relates to an energy conversion device comprising a rotating electrical machine capable of converting electrical energy into mechanical energy and / or vice versa. The invention relates to the cooling of such a rotating electrical machine.

[0032] One area of ​​application for the invention is the generation of electrical energy from mechanical energy supplied by a gas turbine for an aircraft engine. However, the invention is also applicable to other types of engines such as, for example, industrial turbines, or turbines for auxiliary power units (APUs).

[0033] The energy conversion device is, for example, a brushless wound-rotor synchronous generator starter, that is, comprising a main electric machine, an exciter, and a rotating rectifier. The energy conversion device then includes a main electric machine, an exciter, and a rotating rectifier bridge connecting the main electric machine and the exciter. The main machine comprises a rotor module with an inductor and a stator module with an armature. The exciter's rotor module forms an armature, and the exciter's stator module forms an inductor. The energy conversion device is configured so that a polyphase alternating current is induced in the exciter's rotor module in generator mode when the exciter's rotor module rotates, while a direct current is injected into the exciter's inductor.The polyphase alternating current induced in the exciter rotor during generation is rectified by the rotating rectifier bridge and then injected into the field winding of the main machine, thus inducing another polyphase alternating current in the armature of the main machine. The frequency of the polyphase alternating current induced in the armature of the main machine varies with the shaft rotation speed.

[0034] The invention may relate to the cooling of the main electrical machine and / or the exciter.

[0035] The energy transformation device may, alternatively, relate only to the main electrical machine or to the exciter or to any other rotating electrical machine.

[0036] In general, the energy transformation device 1 includes, as can be seen in figure 3 A rotating electrical machine (MV) comprising a rotor module 6 and a stator module 7 comprising an inductor and an armature magnetically coupled to each other and mounted to rotate relative to each other. The inductor is included in the rotor module and the armature is included in the stator module, or vice versa.

[0037] The rotating machine MT comprises a shaft 5 extending longitudinally along a longitudinal axis x and designed to rotate in a predetermined direction around the longitudinal axis. The shaft 5 is a hollow shaft. It comprises a body 50 delimiting an internal volume 51 extending longitudinally along the x-axis.

[0038] The rotor module 6 is fixed to the shaft 5. The rotor module 6 and the shaft 5 are intended to rotate, around the x-axis, relative to the stator module 7. Drive means are advantageously provided to drive the shaft 5 in rotation around its x-axis.

[0039] The rotor module 6 radially surrounds the shaft 5. The stator module 7 radially surrounds the rotor module 6. In the following text, the terms radial and axial are defined with respect to the x-axis.

[0040] Preferably, the rotor module 6 completely surrounds the x-axis. In other words, the rotor module 6 completely surrounds the shaft 5 radially, that is, in a plane perpendicular to the x-axis. Similarly, the stator module 7 advantageously completely surrounds the x-axis radially. In other words, the stator module 7 completely surrounds the rotor module 6 radially, that is, in the plane perpendicular to the x-axis.

[0041] The MT rotating machine includes a housing 2 fixed relative to the stator module 7.

[0042] The housing 2 delimits an internal volume of the housing V. The stator module 7 and the rotor module 6 are arranged inside the internal volume of the housing V and are surrounded by a cavity 3 which is part of the internal volume of the housing V.

[0043] The cavity 3 completely surrounds radially the part of the shaft 5 located in the internal volume of the housing V delimited by the housing 2. This part of the shaft extends axially from an axial position E1 of the shaft 5 to an axial position E2 of the shaft 5.

[0044] The internal volume 51 is closed axially at the level of the second position E2.

[0045] Cavity 3 surrounds the rotor module 6 and the stator module 7.

[0046] Advantageously, cavity 3 completely surrounds the rotor module 6 and the stator module.

[0047] In other words, cavity 3 completely surrounds radially and axially in both directions the rotor module 6 and the stator module 7. By cavity 3 completely surrounds radially the rotor module 6 and the stator module 7, we mean that cavity 3 radially separates the stator module 7 from the housing 2.

[0048] The cavity 3 radially separates from the housing 2, an external surface 71 radially delimiting the stator module 7 and located opposite the housing 2.

[0049] Cavity 3 is thus delimited by the housing 2, the rotor module 6, the stator module 7 and the shaft 5.

[0050] Device 1 includes an oil circulation circuit 8 configured to circulate oil in a closed loop. The oil circulation circuit 8 includes a pump 10, a reservoir 9, the internal volume of the shaft 51, and nozzles, which will be described later. The circulation pump 10 is designed to draw oil H from an oil reservoir 9 and inject it into the internal volume 51 of the shaft 5. The oil H is injected upstream of nozzles, which will be described later. The oil injected into the volume 51 exits the volume 51 through the nozzles as the shaft 5 rotates around its longitudinal axis x, forming an oil mist in the cavity 3. The oil mist is designed to come into direct physical contact with the rotor module 6 and the stator module 7, thereby cooling the rotor module 6 and the stator module 7.

[0051] Advantageously, the oil circulation circuit 8 includes a heat exchanger 11 through which the pump 10 injects oil into the internal volume 51 of the shaft 5 so as to cool the oil drawn from the oil reservoir 9 before injecting it into the internal volume. Indeed, the temperature of the oil forming the oil mist increases upon contact with the stator module 6 and the rotor module 7 before falling back down, under the effect of gravity, into the reservoir 9.

[0052] The pump 10 is mechanically coupled to the shaft 5 so as to be driven in rotation by the shaft 5 and is configured so that the flow of oil injected by the pump 10 into the internal volume 51 increases with a rotational speed of the hollow shaft 5 in the direction of rotation.

[0053] The pump 10 is a conventional rotary positive displacement pump, mechanically coupled to the hollow shaft 5, which rotates around the longitudinal axis of the hollow shaft. When the generator unit operates at variable speed, the oil flow rate delivered by this type of pump increases with the rotational speed.

[0054] When the generator device operates at variable speed, the oil flow delivered by this type of pump is, to a first approximation, proportional to its rotational speed.

[0055] The part of device 1 located in housing 2 is schematically represented in two radial sections, in figures 4 And 5 Tree 5 rotated 90° around the x-axis between the figures 4 And 5 .

[0056] An exciter and a rotating rectifier bridge could be arranged inside the internal volume delimited by the housing 2 but are not shown in this figure.

[0057] Oil is injected axially into the internal volume 51 at a first position E1 along the x-axis, in the direction shown by the arrow visible in figures 4 And 5 , to generate an oil flow along the longitudinal x-axis. The direction of the arrow defines a direction going from upstream to downstream.

[0058] As seen in figure 4 , in order to allow the cooling of the rotor module 6 and the stator module 7, the shaft 5 includes a set of at least one nozzle 52, 53, 54, 55 (four nozzles 52 to 55 in the non-limiting embodiment of the figure 4 ) cooling of the rotor module 6 and the stator module 7, passing through the body 50 to ensure fluidic communication between the internal volume 51 and the cavity 3.

[0059] The oil is injected by the pump 10 upstream of the assembly by at least one nozzle 52 to 55.

[0060] The assembly of at least one nozzle 52 to 55 is configured so as to form an oil mist in the cavity 3 from a portion of the oil injected axially into the internal volume 51. In other words, each cooling nozzle of the rotor module 6 and the stator module 7 is configured and arranged to project a portion of the oil injected into the internal volume 51, upstream of the nozzle 52, 53, 54 or 55, into the cavity 3 so as to form an oil mist in the cavity 3 intended to come into direct physical contact with the rotor module 6 and the stator module 7.

[0061] Each cooling nozzle of the rotor module 6 and the stator module 7 includes, for example, a conduit formed in the body 50 and passing through the body 50 so as to put the internal volume 51 in fluidic communication with the cavity 3.

[0062] In the non-limiting example of the figures, each cooling nozzle 52 to 55 of the rotor module 6 and of the stator module 7 extends longitudinally radially to the x-axis.

[0063] Alternatively, at least one cooling nozzle 52 to 55 of the rotor module 6 and of the stator module 7 has a different orientation and / or geometry, provided that it opens both into the internal volume 51 and into the cavity 3. At least one cooling nozzle extends, for example, longitudinally in a plane inclined with respect to a plane perpendicular to the x-axis.

[0064] In the following text, the term "jet" refers to a cooling jet for the rotor module 6 and the stator module 7 as defined above. It should be noted that the device according to the invention could include other jets suitable for cooling other parts of the device, such as ball bearings.

[0065] Each nozzle comprises an inlet e through which oil enters the nozzle and an outlet s through which oil exits the nozzle and enters cavity 3. For clarity, only the inlet e and outlet s of nozzle 52 are referenced in figure 4 , and only in figure 4 .

[0066] The stator module 7 and the rotor module 6 each comprise a generally cylindrical body C7 and C6, respectively, comprising a stack of radially stacked laminations. The rotor module 6 comprises a winding comprising at least one coil. The winding includes coil heads T6 projecting axially from the body C6 of the rotor module 6. The stator module 7 comprises a winding comprising at least one coil. The winding includes coil heads T7 projecting axially from the body C7 of the stator module 7.

[0067] Body C7 extends advantageously over the entire length of body C6 along the x-axis.

[0068] In the particular but not limiting embodiment shown in the figures, the outlets of the cooling nozzles of the rotor module 6 and the stator module 7 are arranged opposite at least one coil head T6, T7 of the rotor module 6 and / or the stator module 7. In this way, the cooling nozzles 52 to 55 of the stator module and the rotor module project the oil directly onto at least one coil head T6 of the rotor module 6 and / or at least one coil head T7 of the stator module 7. This ensures efficient cooling of the module in question by projecting the oil opposite the coil heads.

[0069] Alternatively, the outlet of at least one jet is positioned opposite the housing 2.

[0070] The oil mist formed by the jets 52 to 55 cools the rotor 6 and stator 7 modules before falling back, by gravity, into an oil reservoir 9 delimited by the casing 2, i.e. forming part of the internal volume of the casing V. The oil reservoir 9 is in fluidic communication with the cavity 3, via possible partitions CL.

[0071] Device 1 is configured so that the oil reservoir 9 is located under the rotor module 6 and the stator module 7, along a vertical axis z, during normal use of device 1. The vertical is a straight line aligned with the gravity vector of device 1.

[0072] According to the invention, the device 1 comprises, as can be seen in figures 4 And 5An assembly of at least one oil mist density control circuit, configured to limit an increase in the oil flow rate from the internal volume 51 to the cavity 3, through the assembly of at least one nozzle 52, 53, 54, 55, beyond a predetermined non-zero minimum oil flow rate Dmin, due to an increase in the oil flow rate injected by the pump 10 into the internal volume 51 resulting from an increase in the rotational speed of the shaft 5 within a predetermined operating speed range of the shaft. This operating speed range extends continuously from a predetermined non-zero minimum speed Vmin to a maximum speed Vmax.

[0073] In other words, the control circuit is configured to limit the increase in oil mist density with an increase in shaft rotation speed. This helps to limit mechanical losses related to rotor rotation in the oil mist.

[0074] The control circuit includes a conduit 21 attached to the shaft 5. The conduit 21 includes a main conduit 22, an inlet conduit 23, visible in figure 4 , and an outlet duct 24, visible in figure 5 The main conduit 22, the inlet conduit 23 and the outlet conduit 24 are portions of the conduit 21.

[0075] The inlet conduit 23 ensures fluid communication between the main conduit 22 and the internal volume 51 so that the main conduit 22 receives, under the effect of the centrifugal force linked to a rotation of the shaft 5 around its x axis in the predetermined direction of rotation, a part of the oil injected into the internal volume 51. This makes it possible to promote the diversion of the oil through the main conduit 22 when the speed increases without having to provide an additional external device, such as, for example, an oil suction pump at the outlet, or an upstream flow control device, such as a regulating valve.

[0076] The conduit 21 is configured so as to conduct the oil which it receives, during the rotation of the shaft 5 in the direction of rotation, around the internal volume 51 to an outlet 25 of an outlet conduit 24.

[0077] The conduit 21 is configured so as to conduct the oil it receives, when the shaft 5 rotates in the direction of rotation, in translation relative to the body 50 of the shaft 5 along the x-axis and / or in rotation relative to the body 50 of the shaft 5 around the x-axis.

[0078] The control circuit includes a venting device configured to vent the oil exiting the outlet conduit 24 into the oil reservoir 9 without contributing oil mist.

[0079] The evacuation device includes a collection hood 31 fixed relative to the housing 2. The collection hood 31 is disposed in cavity 3.

[0080] The collection hood 31 surrounds at least radially an outlet 25 of the outlet conduit 24 so as to collect at least part of the oil exiting the conduit 21 under the effect of centrifugal force, during the rotation of the shaft 5 in the direction of rotation.

[0081] Advantageously, the hood 31 is configured and arranged so as to retain radially and, preferably, but not necessarily axially in one or both directions, the oil flow ejected at the outlet 25 of the outlet conduit 24. The oil is deposited on the walls of the hood 31.

[0082] The hood is configured so that the oil retained by the hood 31 is collected, under the effect of gravity, in the oil reservoir 9. Thus, the oil collected by the hood 31 is pumped directly to the oil reservoir 9 by gravity, without forming oil mist in the cavity 3.

[0083] The evacuation device includes, for example, an evacuation opening 32 arranged opposite the oil reservoir 9 so as to evacuate the oil collected by the hood 31, under the effect of gravity, into the oil reservoir 9. Thus, the oil which deposits on the walls of the hood 31, flows towards the evacuation opening 32 and falls, through the opening 32, into the oil reservoir 9 under the effect of gravity.

[0084] Advantageously, the discharge opening 32 is configured and arranged so that the oil exiting through the opening 32 is not projected directly onto the rotor module 6.

[0085] More advantageously, the discharge opening 32 is configured and arranged so that the oil exiting through the opening 32 is not likely to come into contact with the rotor module 6. Thus, the opening 32 is configured and arranged so that the oil exiting the opening 32 is not projected directly onto the rotor module 6 and is not likely to be projected indirectly onto the rotor module 6, for example by projection onto a surface close to the rotor module 6.

[0086] Advantageously, the discharge opening 32 is located at a radial distance from the x-axis greater than or equal to the highest radial distance separating the coil heads T6 from the rotor module 6 or the rotor module 6 from the axis.

[0087] The cover 31 completely surrounds the shaft 5 radially and is fixed relative to the housing 2. It therefore prevents the ejection, towards the rotor and stator modules, of at least some of the oil carried by the outlet duct 23, which rotates around the x-axis with the shaft 5 under the effect of centrifugal force. The oil, thus slowed, no longer possesses the kinetic energy necessary to form oil mist and is forced directly back to the reservoir 9 under the effect of gravity, without forming oil mist.

[0088] Thus, the control circuit according to the invention makes it possible to divert at least part of the excess oil supplied by the high-speed pump and return it directly to the reservoir 9 without forming oil mist. This limits the increase in mechanical losses at high speed.

[0089] The solution is simple to implement, requiring only the addition of at least one conduit to the rotor assembly (rotor module and shaft) and the collection device. Furthermore, this solution is relatively reliable and inexpensive because it does not require the addition of components with moving parts, such as control valves. By selecting the conduit configuration, this solution allows for gradual control across the entire speed range and precise regulation of oil flow rates throughout the operating speed range. This solution is less susceptible to oil contamination than a solution based on opening / closing an orifice. This solution does not introduce any risk of resonance with the oil circuit.

[0090] In the specific realization of figures 4 And 5 The outlet conduit 23 is a groove, visible in figure 5 , formed on the external surface S of the hollow shaft 5. The groove 24 is closed by a closing hood 26 fixed relative to the shaft 5 so that the oil injected by the main conduit 22 into the groove 24 remains confined in the groove until the outlet 25 of the groove 24.

[0091] In the non-exhaustive implementation of the figure 5 , groove 24 extends linearly along the x-axis. Alternatively, groove 24 could be curved.

[0092] Conduits 27, 28 are provided in the closing cover 26. These conduits pass radially through the closing cover 26 and are open opposite first conduits 58, 59, provided in the body 50 of the shaft 5 and passing radially through the body 50, and opposite the cavity 3.

[0093] Conduit 27 and the first conduit 58 form nozzle 54, and conduit 28 and the first conduit 59 form nozzle 55, in the non-limiting embodiment of the figure 5 .

[0094] In the non-exhaustive implementation of figures 4 And 5 The closing cover 26 completely surrounds the hollow shaft 5 radially. The closing cover 26 includes a radial opening OR, visible in figure 5 , located opposite a longitudinal end of the groove 24 so as to form the outlet 25 of the groove 24.

[0095] It should be noted that groove 24 is located in a radial plane distinct from nozzles 54 and 55. These planes form a 90° angle around the x-axis in the example of figures 4 And 5 .

[0096] More generally, groove 24 is advantageously positioned in a radial plane distinct from any nozzle located in the same plane perpendicular to the x-axis as the groove. This prevents fluid communication between conduit 11 and nozzles 54 and 55.

[0097] The collection hood 31 can be mounted on the housing 2 or on a housing containing a ball bearing to guide the shaft 5 in rotation around the x-axis relative to the housing 2.

[0098] In the non-exhaustive implementation of the figure 5 The collection cover 31 includes a ring B completely radially surrounding the shaft 5 opposite the outlet 25 of the groove 24, or more generally the outlet of the outlet conduit. The ring B is fixed relative to the housing 2.

[0099] A functional clearance exists between the collection cover 31 and the shaft 5 to allow rotation of the shaft relative to the collection cover 31. Advantageously, the size of this clearance is as small as possible to allow this rotation while minimizing oil ejection through the functional clearance. Alternatively, the minimum radial distance between the collection cover 31 and the shaft 5 is greater than the functional clearance and is chosen based on a cost / performance compromise.

[0100] Ring B is configured and arranged so as to retain radially and axially in both directions the oil exiting through outlet 25. The oil is deposited on the walls PC, PT1, PT2 of the ring and flows down to an opening 33, provided in ring B, under the effect of gravity.

[0101] Ring B comprises, for example, a generally cylindrical wall PC completely surrounding the shaft 5 radially opposite the outlet 25, and two transverse walls PT1 and PT2 substantially perpendicular to the x-axis. The outlet 25 is entirely contained between the two transverse walls PT1 and PT2. The cylindrical wall PC has an opening 33.

[0102] Advantageously, the ring B is equipped with a drain pipe T that completely surrounds the opening 33 and extends from the opening 33 to the drain opening 32 located opposite the oil reservoir 9. The drain pipe T contains the oil from the drain opening 32 within a tubular volume defined by the pipe before it is discharged through the drain opening 32. The oil running over the ring flows down the drain pipe to be discharged directly into the reservoir without contributing to the formation of oil mist. The pipe 31 also guides a portion of the oil expelled from the outlet of the conduit directly to the oil reservoir 9, directly opposite the opening 32 during shaft rotation, so that it does not contribute to the oil mist.

[0103] Pipe T is connected to ring B.

[0104] The T-pipe is integral with the B ring. It is a single unit with the ring. Alternatively, the pipe is fixed to the B ring.

[0105] In another variant, the pipe T has one end fixed to the ring B and one end movable relative to the ring B, for example when the pipe T is flexible.

[0106] The pipe T is tubular, for example, essentially cylindrical. Alternatively, the pipe widens from the opening 33 towards the discharge opening 32, or vice versa. It is, for example, generally frustoconical. The advantage of widening the pipe from the opening 33, or from a plane perpendicular to the pipe axis and located between the planes defined by the opening 32 and the opening 33, up to the discharge opening 32, is to ensure the evacuation of oil to the reservoir even in the event of pitching or rolling of the machine, and therefore of the x-axis. The advantage of narrowing the pipe from opening 33, or from a plane perpendicular to the pipe axis and located between the planes defined by the discharge opening 32 and opening 33, is to properly channel the oil jet exiting the discharge opening 32, directing it precisely towards the oil reservoir or to a specific point within the oil reservoir. The shape of the T-shaped pipe is adapted according to the requirement.

[0107] The method of implementation of figures 4 And 5 This is not a limiting case; other embodiments are of course possible. For example, the cover 31 is without the pipe 32. The drain opening 32 is then the opening 33.

[0108] In the construction of the figures, the conduit 21 comprises the main conduit 22, the inlet conduit 23 and the outlet conduit 24. Alternatively, the inlet conduit and / or the outlet conduit is a portion of the main conduit.

[0109] The rotor module 6 is radially delimited (with respect to the longitudinal axis x) by an external surface 61 facing the stator module 7, i.e. opposite the stator module 7, and an internal surface 62 facing the shaft 5, i.e. opposite the shaft 5. These surfaces 61 and 62 are surfaces of the body C6 of the rotor module 6.

[0110] In the advantageous realization of figures 4 And 5The main conduit 22 is entirely situated between an internal surface 5i of the shaft body 50, the internal surface 5i facing the free volume 51 and delimiting the free volume 50, and the external surface 61 of the rotor module 6. The circulation of oil in the main conduit 22 thus ensures a dual function: regulating the flow of oil exiting the nozzles 52 to 55 and cooling the rotor module 6. The proposed solution therefore constitutes an additional means of cooling the rotor module 6, thereby improving the performance of the energy conversion device 1. The gain in energy performance is all the greater when the main conduit 22 is configured to circulate the oil over a large distance in translation relative to the shaft 5 along the x-axis and / or in rotation relative to the shaft body 5 around the x-axis.

[0111] In the advantageous realization of figures 4 And 5The main conduit 22 is formed in the body 50 of the shaft 5 and is closed by the rotor module 6, specifically by the internal surface 62 of the rotor module 6. This solution has the advantage of being easy to implement, particularly when the shaft 5 has a one-piece structure, as the conduit 21 can be easily machined, for example, into the surface of the shaft body 50. Furthermore, the oil carried in the conduit 21 comes into direct contact with the internal surface 62 of the rotor 6, thus ensuring good cooling of the rotor 6. This solution also has the advantage of being compact. It does not require the addition of a dedicated part in which the conduit would be formed.

[0112] Alternatively, the main conduit 22 is formed inside the body 50 of the shaft 5 and closed solely by the body 50 of the shaft 5. In this case, the body 50 can be obtained by additive manufacturing (3D printing) or be formed of two tubular parts, one of which is nested inside the other. In the latter case, one of the parts includes a channel and the other closes it to form the main conduit 22, or the main conduit is formed of two channels formed on the surface of each of the tubular parts, the conduit being formed and closed by nesting one of the parts inside the other.

[0113] In another variant, the main conduit is provided only in the rotor module 6 from a channel provided in a first body attached to the radial stack of sheets of the C6 body of the rotor module 6 and possibly from another channel provided in a second body attached to the first body.

[0114] The channel or channels from which the main conduit is formed are, for example, produced by machining from a body. Alternatively, at least one channel from which the main conduit is formed is produced, for example, by 3D printing, by electrical discharge machining (EDM) casting, or by sintering.

[0115] Alternatively, at least a portion of the main conduit 22 is provided between the internal surface of the stator module and the internal surface 62 of the rotor module 6.

[0116] In general, at least a portion of the main conduit is radially surrounded by the stator module 7.

[0117] The additional cooling provided by this solution is all the better as the conduit circulates the oil over a large distance around the internal volume rotating around the internal volume 51 tangentially and / or axially.

[0118] Advantageously, the main conduit 22 is configured to circulate the oil it receives over most of the length of the C6 body of the rotor module 6 and, preferably, over the entire length of the C6 body of the rotor module 6 along the x-axis.

[0119] In the advantageous realization of figures 4 And 5The main conduit 22 is a coil wound in turns around the internal volume 51. This solution is advantageous because it provides a good heat exchange surface between the oil and the rotor module 6. Furthermore, the temperature of the oil carried by the conduit increases monotonically with the distance it travels along the longitudinal axis x from the inlet of the main conduit. It does not generate significant, and more problematic, temperature differences in the same plane perpendicular to the longitudinal axis within the rotor module 6. If a temperature gradient exists as a function of the angle formed around the x-axis, a mechanical imbalance can be generated by different thermal expansions of the rotor module 6 around the x-axis.

[0120] Preferably, the main conduit 22 is wound in a circular helix around the x-axis. The axis of the helix is ​​the longitudinal x-axis. A circular helix is ​​defined as a helix inscribed within a cylinder of revolution. It should be noted that the helix is ​​not necessarily circular.

[0121] Advantageously, the conduit 21 is configured to draw oil during the rotation of the shaft 5 in the predetermined direction of rotation. The conduit 21 then acts as a pump that draws a portion of the oil injected by the pump 10 into the internal volume 50.

[0122] Advantageously, the conduit 21 is configured to draw oil as the shaft 5 rotates in the predetermined direction of rotation, such that the oil flow drawn through the conduit 21 increases monotonically over the entire operating speed range of the device. The operating speed range of the device is the range of rotational speeds within which the shaft 5 is intended to rotate for the transformer to supply electrical energy to a load or network. This allows the conduit 21 to have a gradual influence over the entire operating speed range and thus regulates the oil flow rates in the nozzles 52, 53, 54, and 55 over the entire operating speed range.

[0123] For this purpose, when the main conduit 22 is wound in a circular helix around the x-axis, the helix is ​​advantageously right-handed when the shaft 5 rotates around the longitudinal axis clockwise as seen from position E2 of the machine shaft. Position E2 is located on the opposite side of the helix relative to position E1 of the machine shaft. The helix rotates right-handed when the shaft 5 rotates around the longitudinal axis clockwise as seen from position E2 of the machine shaft, along the x-axis (to the right in the figure), in the direction in which the oil is injected into the internal volume 51. The oil is injected at the first position E1 of the shaft, along the axis, in the non-limiting embodiment of the figure 3 , towards position E2. If the direction of rotation of the shaft is counterclockwise viewed from position E2 towards E1, or if the oil is injected in the direction from position E2 towards position E1 and the rotation of the shaft is clockwise viewed from E2, then the propeller is left-handed. It rises in a clockwise direction.

[0124] The configuration of the main conduit 22, designed to achieve suction by helical effect when the shaft 5 rotates in the predetermined direction, allows for an increase in the aspirated oil flow rate with increasing speed. This increase can, for example, be monotonic. Since the suction through the conduit 21 is a function of the shaft's rotational speed, it is possible, by correctly adjusting the conduit's geometric parameters, to influence the oil flow rate exiting the nozzle assembly 52 to 55 across the entire operating speed range.

[0125] Conversely, if, in order to adjust the flow rates of the nozzles 52 to 55, it is necessary to limit the suction in the propeller at high speeds (for example if the centrifugal forces become too great, for example in the case of a machine of large diameter and / or high rotational speed), it is sufficient to reverse the direction of rotation of the propeller in order to obtain the opposite effect.

[0126] Adjusting the propeller pitch allows for control of the suction in the duct 21. Adjusting the propeller cross-section and the geometric characteristics of the inlet channel 22 and the outlet channel 23 allows for control of the pressure losses in the duct.

[0127] There figure 6 The diagram, shown in bold, represents the oil flow rate D1(v) exiting the set of nozzles 52 to 55 as a function of the angular speed v of the shaft (5), when the transformation device is without the oil regulating device. The oil flow rate D(v) has a minimum value Dmin for the minimum speed Vmin of the operating speed range PV. The flow rate increases linearly with speed, over the operating speed range up to Vmax, due to the increase in the flow rate injected by the pump into the internal volume 50 with speed.

[0128] The thin line curve represents an example of oil flow D2(v) exiting the set of nozzles 52 to 55 as a function of speed when the device according to the invention includes the regulation circuit according to the invention and the conduit is calibrated so as to absorb all the excess oil flow injected by the pump 10 into the internal volume 50, beyond the minimum flow when the speed exceeds the minimum speed Vmin, up to the maximum speed Vmax.

[0129] In general, the geometric characteristics of the conduit 21 are defined so that it absorbs all or part of the excess of the oil flow injected by the pump 10 into the internal volume 50, beyond the minimum flow Dmin between the minimum speed and the maximum speed.

[0130] Advantageously, the geometric characteristics of the conduit 21 are defined such that the increase in the flow rate exiting the nozzle assembly due to an increase in the shaft rotational speed is substantially zero or less than in the absence of the control circuit, over the entire rotational speed range from Vmin to Vmax. It should be noted that a substantially zero increase in the flow rate exiting the nozzle assembly corresponds to a constant flow rate exiting the nozzle assembly.

[0131] Alternatively, the geometric characteristics of the conduit 21 are defined so that the increase in the flow rate exiting the nozzle assembly due to an increase in the rotational speed of the shaft is lower than in the absence of the control circuit, at least at an operating speed extending Vmin to Vmax and without the flow rate exceeding the flow rate exiting the nozzle assembly in the absence of the control circuit over the entire operating speed range.

[0132] It should be noted that the geometric characteristics of the duct 21 can be defined so that the flow rate exiting the nozzle assembly decreases over a sub-range of speeds within the operating speed range or over the entire operating speed range. Alternatively, the geometric characteristics of the duct 21 can be defined so that the flow rate exiting the nozzle assembly is substantially constant between Vmin and an intermediate speed and increases from the intermediate speed onward. The geometric characteristics of the duct 21 are adapted as required.

[0133] All flow curves between D2(v) and D1(v) can be obtained. It is even possible to obtain a flow curve with at least one portion less than or equal to D2(v).

[0134] The proposed solution therefore makes it possible to limit oil mist by regulating the flow of oil sprayed by nozzles 52 to 55 over the entire operating speed range of the machine.

[0135] The geometric characteristics of the conduit are, for example, defined using a finite element method to calculate the various flow rates within the energy conversion device. The geometric parameters of the conduit are adjusted iteratively until a predetermined oil flow curve is obtained at the outlet of the nozzle assembly over a predetermined speed range, for a predetermined oil flow curve supplied by a pump at the inlet of shaft 5 over the predetermined speed range, and for predetermined nozzle geometric characteristics. Alternatively, the definition of the conduit's geometric characteristics could be achieved through analytical modeling or an iterative experimental approach.

[0136] In the construction of the figures, the rectangular section of the helix is ​​identical along the entire length of the helix.

[0137] This embodiment is not limiting. The duct cross-section may, for example, be U-shaped, i.e. rectangular with two rounded adjacent vertices, or circular, or have another closed plane curve shape.

[0138] Alternatively, the shape of the helix cross-section and / or the dimensions of the cross-section and / or the pitch of the helix and / or the direction of the helix change along the helix, that is, along the shaft. It is, for example, possible to change from a right-handed helix to a left-handed helix.

[0139] In the embodiments of Figures 4 and 5, the main conduit 22 is helical. Alternatively, the main conduit extends linearly along the x-axis. Alternatively, the main conduit comprises conduit segments extending substantially linearly along the x-axis and distributed angularly around the x-axis. These conduit segments are connected by curved conduits, for example, U-shaped ones. In these cases, the conduit no longer provides suction by helical effect. Instead, the centrifugal force limits the increase in flow rate in the nozzles with increasing shaft speed.

[0140] Advantageously, the outlet section of the duct has a larger area than the inlet section. This allows for better expulsion of the oil by centrifugal force. However, this characteristic is not mandatory.

[0141] In the realization of figures 4 And 5The energy conversion device comprises a single control unit. Alternatively, it comprises several control circuits and therefore several conduits, which may have the same or different shapes. The control unit may, for example, include several helical conduits.

[0142] Several control circuits or conduits may share the same evacuation device, or the evacuation devices of the different conduits may be separate.

[0143] In the figures, the shaft includes a body 50 delimiting the internal volume 51 into which the oil is injected. The internal volume 51 is free. In other words, the internal volume is intended to be completely filled with oil during the operation of the device. The conduit can be completely filled with oil or filled with oil and air during the operation of the device.

[0144] Alternatively, the internal volume 51 comprises a hollow or solid inner body completely surrounded radially by the body 50. The internal volume 51 also includes a free volume for receiving oil during operation of the device. This free volume may comprise a volume surrounded by the inner body and / or a tubular volume radially surrounding the inner body and surrounded radially by the body 50.

[0145] In the figures, the inlet of the conduit 21 is located upstream of some of the nozzle inlets along the x-axis, and the outlet of the conduit is located downstream of the nozzle inlets along the x-axis. Alternatively, the inlet of at least one nozzle is located upstream of the inlet of the conduit 21 and / or the inlet of at least one nozzle is located downstream of the outlet of the conduit 21.

Claims

1. Energy conversion device (1) which is capable of producing electricity from mechanical energy and / or vice versa, the energy conversion device comprising: - a housing (2), - a shaft (5) comprising a body (50) which defines an inner volume (51), the shaft being intended to rotate in a predetermined direction about a longitudinal axis (x) relative to the housing (2) over a predetermined rotational speed range, - a rotor module (6) which is fixedly joined to the shaft (5), - a stator module (7) which is fixedly joined to the housing (2), the rotor module (6) and the stator module (7) comprising an inductor and an armature which are coupled magnetically to each other, the housing (2) delimiting an inner volume which accommodates the rotor module and the stator module and comprising a cavity (3) which surrounds the rotor module (6) and the stator module (7), - an assembly of at least one nozzle (52, 53, 54, 55) which extends through the body (50) and ensures fluid communication between the inner volume (51) and the cavity (3), the assembly of at least one nozzle (52, 53, 54, 55) being configured to form an oil mist in the cavity (3) under the effect of the rotation of the shaft (5) in the rotational speed range, from a portion of an oil injected into the inner volume (51) of the hollow shaft (5), the oil mist being intended to come into direct physical contact with the rotor module (6) and the stator module (7), - an assembly of at least one control circuit which is configured to limit an increase of the oil flow passing from the inner volume (51) to the cavity (3) through the assembly of at least one nozzle (52, 53, 54, 55), the increase being a result of an increase of the oil flow injected into the inner volume (51), the control circuit comprising: - a conduit (21) which is fixedly joined to the shaft (5) and which comprises an input which communicates with the inner volume (51) in order to receive under the effect of the rotation of the shaft (5), another portion of the oil injected into the inner volume (51), the conduit (21) leading the other portion of the oil up to an output of the conduit (21), - a discharge device which is configured to discharge at least a portion of the oil leaving the conduit (21) into an oil tank (9) without contributing to the oil mist.

2. Energy conversion device according to the preceding claim, comprising an oil circulation pump (10) which is configured to remove oil from the oil tank (9) and to inject it into the inner volume (51) of the shaft (5), the pump (10) being coupled mechanically to the shaft (5) in order to be driven in rotation by the shaft (5) so that an oil flow injected by the pump (5) into the inner volume (51) increases when the rotational speed of the shaft (5) increases in the rotation direction.

3. Energy conversion device according to either of the preceding claims, wherein the conduit (21) comprises a main conduit (22) which is surrounded radially by the stator module (7) and which is configured to guide the oil which it receives, during the rotation of the shaft (5), in translation relative to the shaft (5) along the longitudinal axis (x) and / or in rotation relative to the body of the shaft (5) about the longitudinal axis (x), about the inner volume (51).

4. Energy conversion device according to the preceding claim, wherein the main conduit (22) of the conduit of a control circuit is provided in the body (50) of the shaft (5) and is closed by the rotor module (6).

5. Energy conversion device according to either claim 3 or 4, wherein the main conduit of the conduit (21) of a control circuit is wound in a helical manner around the longitudinal axis (x) and is configured to draw in oil at the input of the main conduit during the rotation of the shaft (5).

6. Energy conversion device according to the preceding claim and according to claim 2, wherein the geometric characteristics of the conduit (21) are defined so that the conduit (21) conveys all or some of a surplus of the oil flow injected by the pump (10) into the inner volume (50) beyond a minimum flow rate, over the entire rotational speed range.

7. Energy conversion device according to any one of the preceding claims, wherein the discharge device comprises a collection hood (31) which is arranged in the cavity (3) and which is fixed relative to the housing (2), the collection hood (31) radially surrounding an outlet (25) of the conduit (21) in order to collect at least a portion of the oil leaving the conduit (21) under the effect of the centrifugal force during the rotation of the shaft (5) in the rotation direction.

8. Energy conversion device according to the preceding claim, wherein the discharge device comprises a discharge opening (32) which is located opposite the oil tank (9) and which enables the oil collected by the hood (31) to be discharged, by means of gravity, to the oil tank (9).

9. Energy conversion device according to either claim 7 or 8, wherein the collection hood (31) comprises a ring (B) which radially completely surrounds the outlet (25) and which is configured so as to retain radially and axially in two directions the oil leaving the conduit (31), an opening being provided in the ring (B) opposite the oil tank (9).

10. Energy conversion device according to the preceding claim, wherein the collection ring (B) is provided with a discharge pipe (T) which has an input which surrounds the opening and which extends up to the discharge opening (32).

11. - Energy conversion device according to any one of the preceding claims, wherein the conduit is configured to limit an increase of the oil flow which passes from the inner volume (51) to the cavity (3) through the assembly of at least one nozzle (52, 53, 54, 55), the increase being a result of an increase of the oil flow injected into the inner volume (51).