Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K49/00—Dynamo-electric clutches; Dynamo-electric brakes
  • H02K49/02—Dynamo-electric clutches; Dynamo-electric brakes of the asynchronous induction type
  • H02K49/04—Dynamo-electric clutches; Dynamo-electric brakes of the asynchronous induction type of the eddy-current hysteresis type
  • H02K49/043—Dynamo-electric clutches; Dynamo-electric brakes of the asynchronous induction type of the eddy-current hysteresis type with a radial airgap
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K9/00—Arrangements for cooling or ventilating
  • H02K9/22—Arrangements for cooling or ventilating by solid heat conducting material embedded in, or arranged in contact with, the stator or rotor, e.g. heat bridges
  • H02K9/225—Heat pipes
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
  • H02K1/12—Stationary parts of the magnetic circuit
  • H02K1/20—Stationary parts of the magnetic circuit with channels or ducts for flow of cooling medium
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection

Definitions

• Electromagnetic retarder with heat sink elements Electromagnetic retarder with heat sink elements
• the present invention relates to an electromagnetic retarder comprising energy dissipating elements.
• the invention aims to facilitate the evacuation of heat generated by certain parts of the retarder traversed by currents.
• the object of the invention is therefore to increase the performance of the retarder by facilitating its cooling.
• the invention finds a particularly advantageous, but not exclusive, application for reducing the speed of a heavy goods vehicle such as a bus or a truck. State of the art
• an electromagnetic retarder assists in braking a vehicle.
• the electromagnetic retarder comprises at least one stator and at least one rotor.
• the stator is connected to a gearbox casing or to a casing of a vehicle transmission bridge. In this case, you do not cut a drive shaft to mount the retarder. When the drive shaft is not cut, we speak of a Focal retarder (registered trademark).
• the stator is fixed to the chassis of the vehicle and the transmission shaft is cut.
• the rotor is in turn connected to a plate coupled to a flange of a universal joint of the drive shaft. This plate is coupled to an input shaft of the vehicle axle or to an output shaft of the gearbox or to a connecting shaft.
• the rotor is in two parts and is located on either side of a stator and rotates around the axis of the stator.
• the stator of the electromagnetic retarder carries a ring of coils, and generates a magnetic field. More specifically, each coil is mounted on a core of magnetic material secured to the stator. The stator is then inductive.
• the rotor is made of magnetic material and is armature. The rotor is shaped to have fins which provide ventilation and cooling of the retarder.
• the rotor carries the ring of coils and the cores.
• the rotor then becomes inductor and in this case, the stator is induced and carries a chamber inside which circulates a fluid for its cooling.
• a retarder also called a Hydral retarder (registered trademark)
• a Hydral retarder registered trademark
• the birth of a braking torque generated by an electromagnetic retarder is based on an eddy current principle.
• the induced stator inside which an inductor rotor turns, is subjected to an electromagnetic field. This field is generated by the coils mounted on the rotor which preferably operate in pairs, each coil being wound around a projecting core belonging to the rotor.
• Each of the pairs of coils forms a magnetic field which closes from one coil core to the other passing through the stator and the rotor.
• currents called eddy currents arise inside the induced stator. These currents generate a braking torque which tends to oppose the movement of the rotor. As the rotor turns with a motor shaft, this braking torque also opposes the movement of the vehicle's motor shaft. This couple therefore participates in a slowing down or stopping of the vehicle.
• the eddy currents cause the stator to overheat. Indeed, the currents flowing through the stator made of conductive materials tend to heat the walls of the stator.
• This heating phenomenon is called the Joule effect.
• This effect is generally observable when an electric current crosses an electric conductor.
• the power of an electromagnetic retarder is therefore limited by its capacity to generate heat from the armatures, in this case the stator.
• This drop in performance is not only due to heating caused by eddy currents but also to a moderate conductivity of the steel.
• the wall of an induced steel stator can reach very high temperatures and very large temperature gradients can be observed between the internal periphery of the stator located opposite the coils and the external periphery of the stator distant from these coils and in contact with the cooling chamber.
• a rotor made of a heat conducting material can also heat up in its parts close to the coils.
• supports carrying electronic voltage rectifier circuits can heat up due to a current flowing through rectifier elements.
• These overheating of the stator, the rotor and the rectifier circuits pose problems for removing heat from the retarder.
• devices which use air flows.
• a finned fan integral with the rotor generates an air flow between the coils of the rotor, which contributes to the evacuation of heat from the stator.
• the walls of this element are hollowed out in order to circulate a coolant in these walls. Heat exchange can then occur between the liquid in the cooling chamber and the heated element.
• cooling chambers are hollowed out in a stator of a retarder and a heat exchange between the hot stator and the coolant makes it possible to cool the stator.
• chambers have added walls and are external to the stator, while being carried by the latter.
• these prior art systems have limits in their operation. Indeed, the cooling power of a slowing device implementing a fan cannot be as high as desired. Indeed, the fan and its cooling fins, because of a very compact design, oppose to the flow of cooling air a significant air resistance. In addition, the convection coefficient in air is relatively low. It is therefore difficult to cool a stator or a rotor using a fan.
• the fan is integrated in the retarder rotor.
• the fan may have a high mass to dissipate heat. The weight and size of the fan therefore adds to that of the retarder.
• the retarder becomes larger and less adaptable to gearboxes speed or rear axles.
• the use of a fan generates noise which can be a nuisance to the driver of the vehicle. Q uencing the cooling chambers, they realize a cooling retarder which remains too low if one wishes to further increase and optimize braking performance of the retarder, especially because of the low conductivity of materials generally isotropic, which are the stator and other organs that give off heat.
• the object of the present invention is to solve the problems of fan noise, size of the fan, and lack of efficiency of this fan or of the cooling chambers. Thanks to its adaptable and efficient cooling device, the invention allows the design of machines offering a very large torque to assist the braking of the motor vehicle.
• the invention greatly reduces the thermal stresses imposed on a retarder.
• the invention makes it possible to obtain an increase in the power of a retarder for given dimensions of this retarder, or even for reduced dimensions of this retarder.
• the invention also allows an increase in the reliability and efficiency of the retarder by reducing losses by the Joules effect and thermal stresses. These thermal stresses are inter alia due to the very high temperature gradients between the peripheries of cooled parts and the peripheries of hot parts which give off heat losses.
• a heat pipe has a closed enclosure in which a heat transfer fluid circulates.
• a heat transfer fluid circulates inside the heat pipe.
• a pressurized fluid which vaporizes in a hot side of the heat pipe and which condenses in a cold side of the heat pipe.
• the warm side of the heat pipe is also called the evaporation area and the cold side of the heat pipe is called the condensation area.
• the heat transfer liquid vaporizes, it takes up heat and when it condenses, it gives up the heat it has accumulated on the hot side.
• the larger the area of the heat pipe in contact with a hot element the more it can conduct the heat of this element.
• the heat pipe enclosure is made of conductive material, such as copper or zinc or nickel, in order to further facilitate the evacuation of heat.
• the heat pipe has a very high equivalent conductivity.
• a heat pipe can reach a conductivity of 10,000 W / mK (Watt per meter Kelvin), while copper, the most conductive of homogeneous materials, has only a conductivity of 400 W / mK
• a heat pipe is therefore 25 times more conductive than copper.
• the steel in which the majority of the parts of a retarder are made it has only a conductivity of 50 W / mK. From this low conductivity of steel comes the utility of adding heat pipes to the interior of retarder parts.
• the use of heat pipes inside a retarder is not exclusive. In general, this use is coupled with the creation of cooling chambers in the walls of the retarder and possibly the use of fans integrated or not inside this retarder.
• the purpose of the heat pipe is to draw heat from a hot or heated part of the retarder inside which it is inserted in order to evacuate it from a cold or cooled part of the retarder.
• the heat transfer fluid allows heat to circulate in the heat pipe so that the heat is evacuated to the cooled part of the retarder.
• the heat pipe then acts as a heat bridge which makes the connection between the heated part and the cooled part of the retarder.
• the mounting of the heat pipe in a retarder is said to be remote.
• the fact that the heat pipe is insulated makes it possible to standardize the temperature in all the room or rooms of the retarder in which the heat pipe is inserted.
• by placing heat pipes inside the retarder in different places it becomes possible to almost eliminate the temperature gradients in the parts of the retarder.
• the heat pipe can take any form.
• the heat pipe can in particular have a tubular or pawn shape.
• the heat pipe can also have a square, triangle, U-shaped, or round section.
• a retarder may include an advantageously annular cooling chamber, in the form of a crown, framing a rotor.
• heat pipes can be inserted into the stator radially with respect to an axis of the rotor.
• a retarder may also include a generally annular cooling chamber, transverse to an axis of rotation of the rotor.
• heat pipes can be inserted inside a stator parallel to an axis of the rotor.
• the heat pipes located in these retarders have a single evaporation zone placed in a heated part of the retarder and in particular of the stator.
• heat pipes placed in a rotor form an angle with an axis of the rotor so that the return of the condensed fluid is facilitated by a centrifugal force.
• These heat pipes can also be parallel to an axis of the rotor and have inclined walls.
• the entire shaft of the rotor is produced in the form of a heat pipe. The walls of the rotor shaft can in this embodiment be inclined relative to the axis of the rotor.
• the heat pipe can be placed inside notches carrying the coils.
• the heat pipe is inserted into the bottom of these notches intended to accommodate a coil.
• the heat pipe can fully or partially enter in cooperation with these notches.
• the ends of the heat pipes corresponding to a condensation zone can be terminated by fins or a blade so as to promote cooling of the heat pipe.
• a retarder comprising a rotating or fixed rectifier electronic circuit
• a heat pipe which passes through a support of this circuit.
• One end of the heat pipe which extends towards the outside of the support may have fins in order to cool the heat pipe in its condensation zone.
• the end of the heat pipe which extends towards the outside of the support ends in a blade, this blade allowing, like the fins, the cooling of the heat pipe.
• Heat pipes can also have two functions. In fact, in addition to their function as heat conductors, these heat pipes can in the case of the rotor or the diode bridge take the form of an axial blade, centrifugal or helico-centrifugal. More precisely, the condensation zone of the heat pipe can take the form of a blade. These heat pipes also have a ventilation function.
• blades of the heat pipe type are installed on a conductive support and this in circumferential alternation with diodes composing the electronic rectifier circuit.
• This alternation allows the heat dissipated by the diodes to be distributed over the entire contour of the support.
• the condensation zone of the heat pipe is closer to the center of rotation of the circuit than the evaporation zone.
• This configuration of the condensation and evaporation zones makes it possible to facilitate the return of the fluid to a liquid state by centrifugal forces.
• the cooling of the bridge by heat pipes can also be applied if the bridge is fixed. This bridge can then be cooled by forced convection of a fluid such as air or water on fins or by means of a surface immersed in a fluid. In this case, the fins or the surface immersed in the fluid correspond to a condensation zone.
• the invention therefore relates to an electromagnetic retarder comprising: - a rotor fixed on a shaft, this rotor carrying coils and comprising an axis and, - a stator carrying a cooling chamber, characterized in that it comprises: - at least one heat pipe comprising a closed enclosure in which a heat transfer fluid circulates, - this at least heat pipe having an evaporation zone absorbing heat, this evaporation zone being located in a hot part of the retarder, a condensation zone restoring heat, this condensation zone located in a cooled zone of the retarder.
• the heat pipe is integrated into the wall of the stator, and the cooling chamber, traversed by a cooling fluid, is located in the condensation area of the heat pipe.
• FIG. 1 shows a schematic representation of an electromagnetic retarder 100 comprising a stator 101 inside which rotates a rotor 110, here of the type described in document EP-A-0331559, attached to a shaft 112 with an axis 120 constituting the shaft of the retarder and of the rotor 110.
• the stator 101 of axial orientation, carries annular cooling chambers 102-106.
• the rotor 110 carries coils 111 and in particular cores of these coils 111 regularly spaced over its entire outer contour.
• the coils 111 of oblong shape as well as the cores, each have an axis passing through their two ends oriented radially with respect to the axis 120 of the retarder.
• the electromagnetic field generated by these coils therefore propagates essentially radially with respect to the axis 120.
• Heat pipes 113 and 116 are located inside the stator 101.
• the coils 111 are therefore electrically powered by an alternator comprising an inductor stator carried by the stator 111 and an induced rotor carried by the rotor 110.
• This alternator not referenced, is visible in the left end of FIG. 1.
• a rectifier bridge intervenes between the induced rotor of the alternator and the coils 111 to supply the latter with direct current.
• a joystick available to the driver allows the electric current flowing in the windings of the alternator stator to be adjusted. For more precision, reference will be made to the aforementioned document showing an example of connection between the rotor 110 and the shaft 112.
• the shaft 112 is in one embodiment the motion transmission shaft of the engine of the vehicle with at least one vehicle wheel, the stator attaching to the gearbox as in document EP-A-331559 or alternatively on the rear axle of the vehicle.
• the shaft 112 is distinct from this transmission shaft by being offset relative to the latter.
• a speed multiplier for example with gear trains, comprising at least two gears, intervenes between this shaft and the shaft and the motion transmission shaft for a reduction in weight and an increase in the performance of the retarder.
• the speed multiplier intervenes between the shaft 112 and a secondary output shaft of the gearbox provided for mounting a retarder of the hydrodynamic type with impeller wheel and turbine wheel.
• the retarder according to the invention is mounted in place of this external retarder.
• the cooling chambers 102-106 are here annular chambers hollowed out entirely in the internal and external peripheral walls 114 and 115 respectively of the stator. In a first variant, these chambers are partially hollowed out in the walls of the stator and closed by adding external covers welded to these walls. In a second variant, these chambers are created by pipes constituting an external cooling circuit.
• a coolant such as the coolant of the internal combustion engine of the motor vehicle, circulates in the cooling chambers 102-106 to ensure cooling of the stator 101. In fact, heat is generated on the surface of the wall 114 in due to an eddy current flow.
• a heat exchange between the hot wall 114 and the cold cooling liquid in contact with these walls makes it possible to evacuate the heat from the stator 101.
• the wall 114 has a low thermal conductivity and a large thickness in order to meet criteria mechanical and magnetic given in specifications. This low conductivity and this large thickness imply very low conduction of the wall 114 and therefore a significant gradient between the internal face of the heated wall 114 and the external face of the cooled wall 114 which is on the side of the coolant. Consequently, to complete the cooling carried out by the chambers 102-106, heat pipes 113 and 116 are inserted inside the stator 101.
• a heat pipe comprises a closed enclosure in which a heat transfer fluid circulates.
• the heat pipe 113 has a heat absorbing evaporation zone. This evaporation zone generally corresponds to one end of the heat pipe 113 which is located in a hot part of the retarder. Here, the evaporation zone is located in the wall 114 of the stator where the eddy currents are born.
• the heat pipe 113 also has a condensation zone restoring the heat stored in the evaporation zone. This condensation zone is located inside the cooling chamber 104.
• the heat pipe 113 makes it possible to reduce temperature differences which may exist inside the wall 114 and between the wall 114 and the wall 115. In fact, the heat pipe 113 therefore plays a role of heat bridge here.
• FIG. 2 shows a diagram of a heat pipe 113 showing its operating principle.
• the heat pipe 113 contains a fluid 230 under pressure in a closed enclosure 210.
• Heat pipe 113 includes an area
• the heat pipe takes a heat represented by the arrows 220.
• This heat causes a first change of state of the fluid 230.
• the fluid 230 passes from a liquid state to gaseous state.
• the vapor resulting from the gaseous state of the fluid 230 rises along the arrow A in the zone 203, which is a cooling zone.
• the rise of the vapor of the fluid 230 towards the cooling zone 203 leads to a second change of state of the fluid 230.
• the fluid 230 which is then in a zone much cooler than the zone 201 of evaporation condenses and becomes liquid.
• the drops of the fluid 230 then fall back into the zone 201.
• This second change of state allows the fluid 230 to transfer all the heat which it had stored during its first change of state.
• the heat transferred to the external medium is represented by the arrows 221.
• the fluid 230 can return to its initial liquid state in the zone 201 of evaporation by capillarity.
• a capillary zone 270 can be developed in a porous medium which lines the wall of the enclosure 210 of the heat pipe 113.
• the capillary zone 270 can be crumbled, formed by layers of fabrics or carpets of metallic threads.
• the capillary zone 270 may also possibly be formed by axial circumferential grooves on the internal face of the enclosure.
• the return of the fluid 230 in a liquid state in the zone 201 can take place under the effect of appropriate forces such as for example gravity forces or centrifugal forces. It is possible to combine the capillarity of the zone and a gravitational or centrifugal force in order to optimize the return of the fluid 230 to an initial position.
• the heat transfer fluid 230 is water and the walls of the enclosure 210 of the heat pipe are made of copper or nickel.
• the heat transfer fluid 230 is methanol and the walls of the enclosure 210 are made of copper, stainless steel or nickel.
• the fluid 230 is ammonia and the walls of the enclosure 210 are made of nickel, aluminum or stainless steel.
• Multilayer walls of different materials can also be used in the heat pipe.
• a multilayer wall is produced by depositing a copper film on a steel surface.
• Figure 3a shows a cross-sectional view of the retarder
• FIG. 3a shows the configuration of the heat pipe 113 having a profile with a T shape.
• This heat pipe 113 is integrated in the internal peripheral wall 114 of the stator 101, here thicker than the external peripheral wall of the latter.
• the heat-evaporation zone 201 of the heat pipe 113 is located inside a wall 114 of the stator
• the cooling chamber 104 traversed by a cooling fluid is located in the condensation area 203 of the heat pipe 113.
• a heat is conducted from the inside of a wall 114 of the stator 101 to the outside of this wall 114.
• a temperature T1 inside the wall 114 can be much higher than the temperature T2 on the outside of the wall 114 .
• the positioning of the heat pipe 113 in the stator 101 makes it possible to standardize the temperature of the wall 114 by reducing it and bringing the temperature T1 close to the temperature T2.
• the thermal efficiency of the retarder 100 is optimized and its braking performance of the shaft 112 is increased tenfold.
• the thermo-mechanical stresses are reduced, the reliability of the retarder is increased and differential dilations are reduced.
• the heat pipe 113 thus makes it possible to keep a constant air gap between the rotor 110 and a wall 114 of the stator. And by keeping this air gap constant, the heat pipe 113 makes it possible to keep constant the performances of the retarder in a lasting manner which could in the past tend to decrease with heating of the retarder.
• a thermal bond exists between the walls 114 and 115 of the stator 101.
• these two walls 114 and 115 are in contact via the cooling chamber.
• the heat pipe 113 it is thus even possible to observe a uniformization of the temperature throughout the stator 101.
• the heat pipe does not necessarily touch the wall 115.
• the heat pipe 113 is securely fixed inside the wall of the stator 101.
• the heat pipe 113 can be screwed inside the stator thanks to a thread 301.
• the stator 101 is in this case tapped to accept the heat pipe 113.
• the heat pipe 113 can be force-fitted into the wall 114 of the stator 101.
• the heat pipe 113 can also be crimped or brazed in the wall of the stator 101, any other form of attachment being possible.
• Heat pipes can have various shapes.
• FIG. 3b thus shows a heat pipe 360 which is bent inside a chamber 104.
• a cooling fluid 380 circulates in this room 104 according to arrow C.
• the heat pipe 360 is in fact bent at an interface between its zone 201 evaporation located in a wall of the stator 101 and its condensation area 203 located in a cooling chamber 104.
• This heat pipe is bent at the outlet of the wall 114 so that the area coming into contact with the coolant 380 is as large as possible.
• the surface of the elbowed heat pipe 360 in contact with the fluid 380 is larger than that of a straight pawn-shaped heat pipe 361.
• This increase in the heat exchange surface allows a retarder to dissipate a lot of heat.
• FIG. 3c shows heat pipes 320-327 placed in a cooling chamber 104 traversed by a cooling fluid 380. These 320-327 heat pipes have an elongated profile in one direction. The cross section of these heat pipes 320-327 to this direction can be circular, elliptical, rectangular, square or U-shaped.
• Heat pipes 320-327 can also be profiled or in a network of profiles.
• the heat pipes can generally have an aerodynamic or hydrodynamic shape or on the contrary a shape which opposes a displacement of a cooling fluid.
• the fluid 380 can become swirling. Indeed, the contact of the cooling fluid 380 with the surfaces of the particularly shaped heat pipes modifies a movement of the fluid and thus makes its flow turbulent. This turbulent flow facilitates the cooling of the retarder 100 by avoiding stagnation of the liquid 380. In fact, the particles of the fluid 380, by this movement effect, are constantly renewed.
• FIG. 3d shows a particular geometry of a heat pipe which has a fin-shaped condensing zone 340.
• This fin 340 is formed by two wings 342 and 343 which extend on either side of a base 341 , in the direction of a flow of a cooling fluid.
• the wings 340 have a slightly rounded shape on one of their dimensions so as to enter in cooperation with an external contour of the stator 101.
• FIG. 3e shows a heat pipe 390 which is an assembly of heat pipes having a condensing zone in the form of fins 340 observed in FIG. 3d.
• the purpose of this assembly is to make the heat pipe 390 describe the entire periphery of the stator 101.
• the fins 340 are slightly curved in order to enter in cooperation with the external contour of the stator 101.
• the assembly fins 340 describes only part of the contour of the stator 101 or even that this assembly is not continuous.
• the fin assembly 340 describes only half of the contour of the stator 101. In another example, only one fin 340 out of three is present to describe the contour of the stator 101.
• FIG. 3f shows a view in section of a heat pipe 330 having a fin-shaped condensation zone. This figure is a side view of the heat pipe 330 along an arrow V in Figure 3a.
• the heat pipe 330 here provides in this variant a thermal connection between an inner wall 114 of the stator 101 and one of its outer walls 115. A fluid circulates in a direction which is perpendicular to that of the drawing, on either side of the heat pipe 330.
• the heat pipe 330 provides an airtight separation between cooling chambers 371 and 372.
• FIG. 4a shows a stator 410 comprising annular chambers 420 and 421 oriented generally parallel with respect to an axis 120 of the retarder rotor (not shown). Inside these rooms 420 and 421, heat pipes 401-405 are present. The heat pipes 402-405 only have one evaporation zone located in a wall of the stator 410. On the other hand, the heat pipe 401 has two evaporation zones. Indeed, the two ends of the heat pipe 401 are integrated into the walls of the stator 410.
• the zone located between these two zones 411 and 412 of heating ensures cooling of the heat transfer fluid .
• the heat pipes 401-405 are oriented radially with respect to the axis 120 of the rotor in order to cool the stator and to standardize its temperature.
• the heat pipes 401-405 can also provide a support and or a connection between the walls of the stator 410.
• the heat pipes 401-405 thus reinforce the structure of the stator 410. In this case, the rotor enters the annular gap present between the two rooms, connected by an unreferenced background.
• the chambers are hollowed out in external and internal concentric walls connected by a transverse bottom not referenced.
• This variant bottom carries a chamber which, in a variant connects the chambers 420, 421.
• This bottom with transverse chamber can be equipped with heat pipes.
• the coils 611 and the rotor enter the annular gap between the two chambers. Thanks to the invention, a precise air gap exists between the rotor and the walls of the retarder stator.
• the alternator is carried in part by the stator and the rotor has an inductor rotor extending in axial projection relative to the chambers.
• a transverse flange made of non-magnetic material connects the rotor to the aforementioned shaft 112.
• FIG. 4b shows an annular cooling chamber 431 which is hollowed out in a stator 430.
• This chamber 431 is situated radially with respect to the axis 120 of the rotor.
• This cooling chamber 431 has heat pipes 421-425 which are oriented parallel to the axis 120 of the rotor.
• the heat pipes 421-425 placed inside this chamber 420 can, as for the realization of the stator 410 of FIG. 4a, include one or more evaporation zones.
• the heat pipes 421, 422, 424 and 425 are placed axially with respect to the axis 120 of the rotor and they have only one evaporation zone located inside the walls of the stator 430.
• the heat pipe 423 is also located axially relative to the axis 120 but it has two zones 440 and 441 of evaporation located inside the stator 430. These two zones 440 and 441 of evaporation make it possible to carry out a thermal junction between the two walls. These two zones 440 and 441 thus optimize heat transfer between the walls of the stator 430 and the cooling fluid.
• the rotor is transversely oriented relative to its axis and carries coils of axial orientation which generate an axial magnetic field.
• the stator is in two parts of the type of Figure 4b. These two parts are arranged on either side of the rotor and are interconnected by a wall of axial orientation, possibly split. An elementary retarder is thus formed.
• FIG. 5 shows the use of a heat pipe 500 establishing a thermal connection between a part 501 and a part 502 of a retarder 510.
• the two parts 501 and 502 of the retarder 510 whose temperature is to be standardized are found side by side.
• These parts 501 and 502 can be separated from each other and the heat pipe 500 which connects them can have any shape and be of variable size.
• the part 501 is the seat of heat releases and the part 502 is a cooled part of the retarder 510.
• the heat pipe 500 therefore has an evaporation zone located inside the part 501 and a zone of condensation located inside the part 502.
• the cold part 502 is oriented above the part 501 to facilitate the return of the heat transfer fluid in a liquid state.
• FIG. 6 shows a shaft 600 rotating around an axis 630 and comprising a rotor 605.
• the shaft 600 is produced in the form of a heat pipe.
• the shaft 600 is divided into three parts 601, 602 and 603 and inclined walls 606-609 are located in its internal space for receiving a fluid.
• the shaft 600 here comprises several condensation zones and an evaporation zone. Indeed, the two ends 601 and 602 of the shaft 600 give up a heat represented schematically by the arrows C and D to an external environment. These ends 601 and 602 are therefore two condensation zones for the shaft 600 produced in the form of a heat pipe.
• the central part 603 of the shaft 600 tends to heat up due to the rotor 605 which surrounds it and which dissipates significant heat in operation.
• This central part 603 is hotter than the ends 601 and 602 of the shaft 600 and therefore corresponds to an evaporation zone.
• This part 603 of the shaft 600 gives up heat represented by an arrow E to the external environment.
• the walls 606-609 are inclined relative to the axis 630 of the rotor 605 in order to promote the return of the heat transfer fluid in the liquid state in the part 603 corresponding to the evaporation zone.
• fins generating a rotation of an air current around these parts can be fixed on these ends 601 and 602.
• FIG. 7 shows a rotor 700 carrying coils 701 which generate an electromagnetic field B.
• This rotor 700 is integral with an axis 702 which drives it in rotation. Fins mounted on the shaft 702 are referenced 703 to 706.
• Heat pipes 710, 711 and 712 are integrated inside the rotor 700. These heat pipes are used to extract calories and standardize the heat inside the rotor 700. These heat pipes 710-712 extend parallel to the axis 750 of the rotor.
• the heat pipes 710 and 711 are terminated on one side by a blade 720, 721 or fins so that the part of the heat pipe beyond the rotor 700 is cooled.
• the heat pipe 712 is ended by two blades 722 and 723 at its two ends in order to achieve a cooling on both ends of the heat pipe 712.
• the choice to end a heat pipe with one or two blades depends on the geometry of the rotor 700 at the place where the heat pipe 710, 711 or 712 is inserted.
• the side of the heat pipe finished with a fin corresponds to a condensation zone and the side of the heat pipe located inside the rotor 700 corresponds to an evaporation zone.
• the heat pipes 710-712 which extend in the example parallel to the axis 750 of the rotor can be of any shape and protrude towards a front part of the rotor 700. Of course, the heat pipes 710-712 can also exit towards a part rear of the rotor 700. As a variant, heat pipes 730, 731 and 732 can extend radially with respect to the axis 750 of the rotor 700. The choice between heat pipes 730-732 oriented radially and heat pipes 710-712 oriented parallel by with respect to the axis 750 is made as a function of a configuration of hot and cold parts inside the rotor 700.
• the shaft 702 of the rotor has, on its peripheral external face, fins 703-706. These fins allow the dissipation of the heat given off by a condensation zone when the shaft 702 is produced in the form of a heat pipe. These fins can form blades.
• FIGS. 8a, 8b, 8c illustrate a particular use of heat pipes in a rotor 800 to cool this rotor 800. In fact, notches 801-804 are produced inside the rotor 800.
• These notches 801-804 are shaped in the bottom to receive heat pipes 820 or 821.
• Heat pipes 820 or 821 are located below the coils not shown in the drawings 8a, 8b and 8c which penetrate into the notches 801-804.
• the heat pipes 820 or 821 can be located at the bottom of a notch, in the middle of this notch or even at the top of this notch.
• These heat pipes can also be inclined or parallel or radial to the axis of the rotor.
• the heat pipes 820 take the form of the bottom of the notches 801-804. These heat pipes 820 can be melted or molded at the bottom of these notches during manufacture of the rotor 800.
• heat pipes 821 can also first be made in a shape complementary to the notch and then be inserted inside this notch .
• the heat pipes 821 have a circular cross section.
• the heat pipes 821 are arranged in the bottom of the notches 801- 804 but they do not fully take the shape of the bottom of these notches 801-804.
• the heat pipes 821 can be placed in the bottom of the notches 801-804 after machining and manufacturing the rotor 800.
• the heat pipes 820 and 821 allow the heat generated by the rotor 800 and in particular its coils to be discharged to the outside.
• the heat pipes 820 and 821 also make it possible to distribute this heat uniformly throughout the metal structure of this rotor 800. Of course, it is possible to fill or insert heat pipes 820 or 821 only inside certain notches 801- 804 of rotor 800.
• FIG. 8c shows other conformations of heat pipes 810-812 inside a rotor 800.
• a heat pipe 810 or 811 can be inserted in rotor 800 and be inclined relative to a axis of symmetry of this rotor 800.
• the heat pipe 812 can also be placed inside the iron sheet of the rotor axially with respect to an axis of rotation of the rotor 800 perpendicular to the plane of the figure.
• the heat pipe 812 can also be located radially or inclined relative to the axis of rotation of the rotor 800.
• the heat pipes each comprise a part which extends beyond the sides of the rotor in order to present a condensation area. This part can include fins or a blades which are integrated or added to the heat pipes.
• FIGS. 9a and 9b show an electronic rectifier circuit 900 mounted on a support 901 conducting heat.
• the circuit 900 notably comprises diodes for carrying out a voltage rectification.
• the circuit 900 and its support 901 rotate in a movement W of rotation.
• a heat pipe 902 is inserted into the support 901 in order to cool the circuit 900.
• the element diodes of electronic circuit 900 tend to heat up due to currents flowing through them.
• the heat dissipated by these diodes is transmitted to the support 901 which carries the bridge 900.
• This heat is then transferred to the outside environment via the heat pipe 902.
• the heat pipe 902 extends towards the outside of the support 901 in the direction of a center of rotation of the movement W.
• Part of the heat pipe 902 inserted into the support 901 corresponds to an evaporation zone 903.
• FIG. 9a schematically represents an example of conformation of the zone 904.
• the zone 904 of condensation comprises fins 910-914 in order to increase the surface of the heat pipe 902 coming into contact with the air for its cooling.
• Figure 9b shows an alternative embodiment of Figure 9a.
• the condensation zone carries a blade 920 to cool it. This blade 920 has a hollow and the whole part of the heat pipe 902 projecting from the support 901 is inserted inside this blade
• This blade 920 has the same function as the fins 910-914, and can additionally force and optimize ventilation.
• the blade 920 can be manufactured directly in the wall of the heat pipe.
• the blade 920 can also be an insert that is fixed, for example by welding, to the heat pipe
• the part of the heat pipe 902 which projects from the support 901 extends in the direction of a center of rotation of the movement W.
• This projection makes it possible to place the zone 904 of condensation lower than the evaporation zone 903.
• a fluid under the effect of centrifugal forces can then return in liquid form to the evaporation zone 903 very quickly in order to optimize.
• diodes making up the circuit 900 are placed on separate bases. These diode bases and heat pipes 902 with fins are alternated over a whole circumference of the support 901 so as to distribute heat well inside all the support 901.
• FIG. 9c shows an alternative assembly in which the circuit
• Heat pipe 902 can have any shape.
• the fixing of the heat pipe 902 to the walls of the heat pipe 902 can be carried out by soldering, welding or gluing or by any other fixing method.
• the shaft 120 of FIG. 1 is, as a variant, the shaft 600 of FIG. 6.
• the rotor of FIG. 1 can be equipped with at least one heat pipe as in FIG. 7.
• the rectifier circuit of the Figure 1 is alternatively provided with at least one heat pipe as in Figures 9a and 9b.
• the stator associated with the rotor of FIGS. 8a and 8b can comprise at least one heat pipe and a cooling chamber as in FIG. 1.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Dynamo-Electric Clutches, Dynamo-Electric Brakes (AREA)

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• 2003
  • 2003-10-31 FR FR0350754A patent/FR2861913B1/fr not_active Expired - Fee Related
• 2004
  • 2004-10-27 EP EP04805322A patent/EP1678814A1/de not_active Withdrawn
  • 2004-10-27 WO PCT/FR2004/002765 patent/WO2005043727A1/fr active Application Filing

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