Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K5/00—Casings; Enclosures; Supports
  • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
  • H02K5/20—Casings or enclosures characterised by the shape, form or construction thereof with channels or ducts for flow of cooling medium
  • H02K5/203—Casings or enclosures characterised by the shape, form or construction thereof with channels or ducts for flow of cooling medium specially adapted for liquids, e.g. cooling jackets
• • 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

Definitions

• Cooling jacket for a rotary machine and rotary machine having such a cooling jacket Cooling jacket for a rotary machine and rotary machine having such a cooling jacket.
• the invention relates to a cooling jacket for a rotary machine, in particular for an electric rotary machine equipping a motor vehicle, and a rotary machine, in particular an electromagnetic driver, comprising such a cooling jacket.
• the need for a particularly well-functioning cooling is not limited to the engine by which the motor vehicle is driven, but also relates to auxiliary equipment such as a generator or an electromagnetic retarder for braking the drive shaft of the vehicle.
• Most of the equipment is air cooled.
• air cooling which is difficult to install, proves to be insufficient, the machines, and in particular the larger ones intended to undergo greater forces, must be cooled by a fluid circulating in a cooling circuit.
• a fluid is for example water, it being understood that this water comprises at least one additive such as antifreeze, for example glycol.
• the fluid flows in a pipe constituting, together with a heat exchanger, a cooling circuit.
• the machines such as heat engines are provided with a cooling duct constituted by a set of ducts very branched to pass the cooling fluid virtually in all corners of the machine.
• rotating machines such as electromagnetic retarders are machines whose cooling must also reach every nook to avoid the formation of "hot spots", a phenomenon detrimental to the operation and endurance of the machine.
• This cooling can be done, for example, by a pipe having the general shape of a helix surrounding the machine to be cooled, because these machines do not have sufficiently thick walls so that one can integrate channels for a fluid cooling.
• rotary electric machines whether generators, reversible machines such as starter generators, or electromagnetic retarders, and the electrical supply means of these rotary electrical machines form assemblies generally comprising a stator traversed by a shaft and a rotor assembled with this shaft so as to have an outer cylindrical surface of the rotor near an inner cylindrical face of the stator with a thin air gap interposed between the rotor and the stator.
• the rotor comprises an inductor with electric wire coils, adapted to generate a magnetic field in an annular ferromagnetic piece of the stator, which constitutes the armature and which is associated with a cooling circuit by a fluid such as water containing an additive as indicated the
• a rotary machine such as, for example, the electromagnetic retarder described in the document cited above, can therefore be considered very schematically as a device in two parts: the first part is constituted by the rotor which is in the form a solid core intended to be mounted on a drive shaft of a driving force that is to be braked, and a stator having the shape of a cylindrical box surrounding the rotor.
• the coils of electrical wires which conduct the electric current of excitation of the retarder form part of the rotor, and the annular piece of ferromagnetic material in which are generated eddy currents, generating a braking force and a warm-up, is part of the stator.
• the annular piece of ferromagnetic material is constituted by a cylindrical drum surrounding the inductor with the interposition of a cylindrical gap. Since the annular piece of ferromagnetic material is a fixed part, it is easy to cool with a fluid, even when it has complex shapes.
• the cooling fluid is passed through a cooling pipe, or cooling jacket, matching the annular piece.
• this cooling jacket comprises, as an integral part, the annular piece of material ferromagnetic, which ensures the direct passage of the cooling fluid on the annular part.
• the cooling jacket or cooling pipe, is advantageously formed by two cylindrical or helical walls, according to the chosen embodiment, one of which, the outer wall, surrounds the other, the inner wall.
• the outer wall being radially spaced from the inner wall, which is formed at least partially by the annular part, these two walls together with two side walls, a passage volume, or a conduit for the cooling fluid.
• the integration of the annular piece of ferromagnetic material in the cooling jacket ensures the best possible direct contact between the cooling fluid and the annular part.
• the design of the two-piece cooling jacket allows for the creation of complex shapes and the use of traditional O-ring seals for the sealing of both parts.
• the section of this pipe which is in direct contact with the cooling machine, extends, for example, along a helix around the annular piece of ferromagnetic material.
• the section of this pipe is formed by a plurality of straight ducts parallel to each other and arranged parallel to the longitudinal axis of the machine to be cooled.
• the section is terminated at each of its two ends by a respective inlet and outlet connection.
• the section of pipe forms, in both cases, in a motor vehicle equipped with such rotary machine, together with an external heat exchanger, the rest of the cooling pipe and a drive pump, a cooling circuit for dissipating a significant amount of heat to the outside.
• the cooling circuit of the rotary machine is connected to the cooling circuit of the engine of the vehicle.
• the birth of a braking torque in an electromagnetic retarder is based on the principle of eddy currents.
• the stator inside which the rotor rotates, is subjected to an electromagnetic field.
• This field is generated by coils mounted on the rotor. These coils work in pairs.
• Each of the pairs of coils forms a magnetic field which closes from one coil to the other passing through the core of a first coil, then into the stator, then into the core of a second coil and into the rotor.
• the induction lines of the magnetic field formed by each of the pairs of coils pass through the ferromagnetic stator.
• the currents that pass through the stator heat the walls of the stator.
• the heat is removed by cooling the walls of the stator.
• a chamber is formed in the outer peripheral wall of the stator in order to be able to circulate a cooling fluid, as described for example in EP-A-0 331 559.
• the cooling of the stator is thus obtained by a heat exchange between the hot stator and the relatively cooler cooling fluid.
• the effectiveness of this cooling depends in part on the dimensions of this cooling chamber or the cooling jacket formed by a conduit (or ducts) surrounding the retarder.
• the coolant must circulate in the cooling jacket, and even in the entire circuit, with a fairly high speed.
• a better convection of heat is obtained by generating turbulence in the fluid flow. The effects of turbulence are particularly favored by a low height of the cooling jacket.
• the cooling jacket formed by the single duct or ducts surrounding the rotary machine is a body having a relatively complex shape and thus posing a number of problems for its manufacture. For this reason, the cooling jacket is often made in two parts which are then joined by welding.
• the object of the invention is to provide a cooling jacket which is not subjected to such stresses, or which is at least to a lesser degree than the cooling jackets used up to now.
• the proposed solution of the invention should at the same time allow to reduce the weight of the retarders, possibly their size and also their manufacturing cost.
• the object of the invention is achieved with a cooling jacket comprising at least one duct intended to be in heat-carrying contact with at least part of a rotary machine to be cooled and having at least one inlet connection and at least one the the
• the cooling jacket comprises an inner wall and an outer wall made of two different materials, the outer wall surrounding the inner wall and being formed radially spaced therefrom to form the conduit through which the fluid passes. cooling.
• the outer wall and the inner wall are assembled with two elastic seals to ensure duct sealing.
• the inner wall is made of a ferromagnetic material and the outer wall is made of a moldable non-magnetic material.
• the use of a ferromagnetic material for the inner wall makes it possible to integrate the stator armature into the cooling jacket.
• the use of a ferromagnetic material for producing the inner wall of the water jacket makes it possible to use the inner wall directly as an armature of the stator and thus to obtain a direct heat-transfer contact between the stator armature and the fluid. cooling.
• the use of a moldable material for producing the outer wall makes it possible to obtain complex shapes of the outer wall of the cooling jacket, the outer wall is advantageously made of a moldable material by gravity, under vacuum or under pressure.
• the differential expansion is all the better controlled that there exists between the outer wall and the inner wall an axial clearance allowing a relative longitudinal displacement of the two walls, but also a radial clearance which is compensated by the presence of minus two elastic joints.
• at least one of these elastic seals is an O-ring.
• the outer wall a light alloy based on aluminum or magnesium and for the inner wall a magnetic steel high yield strength.
• the use of a light alloy for the outer wall significantly reduces the weight of the electromagnetic retarders or other rotating electrical machines equipped with a cooling jacket according to the invention.
• the use of a low alloy magnetic steel having a high yield strength for the inner wall optimizes the thermomechanical characteristics of the cooling jacket.
• the embodiment of the cooling jacket according to the invention in two parts, if necessary even in more parts, makes it possible to better adjust the height of the cooling fluid in the cooling jacket and consequently its exchange capacity.
• a low fluid thickness increases heat exchange and promotes turbulence effects. Optimization consists of the adjustment between the fluid height and its impact on the cooling system pressure drops.
• the main disadvantages of the grinders not using the present invention are their high weight, their size and the maximum temperature they can withstand.
• the realization of the cooling jacket in two different materials facilitates the manufacture of the cooling jacket and reduces the weight of the retarder.
• This principle makes it possible to use, for example, a cast aluminum to facilitate the production of the outer wall and in particular of its complex shapes both for the inlet and outlet connections of the cooling jacket and for the adaptation of the walls. to facilitate flows and avoid hot spots. These arrangements then make it possible to optimize the operation by controlling the flow of the fluid with turbulence, minimizing the pressure losses and a good distribution of the heat exchange surfaces.
• the use of a cast aluminum also offers the advantage of an inexpensive manufacturing process and providing a good compromise between weight and strength.
• the inlet connection (s) and the outlet connection (s) are oriented each at least approximately along the inlet or output axis of the corresponding conduit.
• the cooling jacket comprises a helical duct having at least one turn intended to surround at least a portion of the machine to be cooled
• the inlet connection and the outlet connection are advantageously oriented along a tangential axis or plane passing through. by a zone circumferential respectively inlet and outlet of the cooling jacket.
• the inlet connection and the outlet connection are also advantageously arranged, in an axial view of the cooling jacket, with a small angular offset between the two connections.
• the inlet connection, the outlet connection and the duct have, all along the path of the cooling fluid, a constant area of their passage sections.
• the cooling jacket comprises two adjacent turns with a common inlet connection and an individual outlet connection for each turn.
• the reverse design i.e., two adjacent turns with an individual inlet connection for each turn and a common outlet fitting, is also conceivable.
• the object of the invention is also achieved with a rotary electric machine comprising a stator the the the the
• the stator and the rotor being of axial orientation
• the rotary electric machine comprising a cooling jacket for cooling the stator, this cooling jacket corresponding to that described above.
• the object of the invention is more particularly achieved with an electromagnetic retarder comprising a stator surrounding a rotor, the rotor comprising induction coils and the stator comprising an armature, and a cooling jacket for cooling the stator, this cooling jacket having an inner wall and an outer wall surrounding the inner wall, the inner wall being formed by stator armature.
• FIG. 1 is a schematic representation of a retarder electromagnetic system with a cooling jacket according to a first embodiment of the invention
• Figure 2 is a schematic representation of a cooling jacket according to the invention
• Figure 3 is a schematic representation of the outer wall of a cooling jacket according to the invention
• Figure 4 is a schematic representation of a detail of the cooling jacket according to the invention, showing in particular one of the connectors of the jacket and the arrangement of two elastic seals according to the invention
• Figure 5 is an axial view of a cooling jacket according to the first embodiment of the invention
• FIG. 6 and FIG. 7 show the evolution of the shape and the cross section of a connector of the cooling jacket according to the invention
• FIG. 8 shows in detail the arrangement of the joints shown in FIG. 4.
• FIG. 1 represents an electromagnetic retarder 1 according to the invention in a perspective view with axial partial section and mounted on a gearbox 2 of a motor vehicle.
• This retarder which is intended to slow down a transmission shaft of the vehicle and more particularly here the output shaft of the gearbox 2, by generating an alternating distribution magnetic field in a ferromagnetic part, comprises a cooling jacket 10 characterized by the presence of a single conduit 11 of helical shape in a single turn.
• the retarder 1 is equipped with a generator 3 intended to provide the excitation energy necessary to generate the alternating distribution magnetic field.
• This generator 3 comprises an inductor stator formed by a ring of coils or windings 4 of electrical wires around cores 5 constituting multiple magnetic poles with alternating polarities, and a rotor 6 constituting an armature of this generator 3.
• the stator surrounds the rotor with a small gap.
• the coils 4 are powered by a direct current source such as a vehicle battery equipped with retarder 1.
• the intensity of this current is adjusted according to the braking torque that the retarder must produce. Indeed, by adjusting the intensity of the induction current of the coils 4, the intensity of the electric current generated by the generator 3 is regulated and, finally, the intensity of the eddy currents braking and heating generators , generated in a ferromagnetic part 14 of the retarder, as described below.
• Generating the electric supply current required for the generation of eddy currents by a generator 3 integrated in the retarder 1 provides a double advantage.
• the first advantage consists of a very low external electrical energy input taken from the vehicle battery, for example of the order of 20 to 30% of the total energy required.
• the second advantage is that the generation of the electric current by the generator itself consumes some mechanical energy taken from the tree to slow down.
• the retarder 1 comprises a rotor 15 having an axis 16 rotatably mounted inside a stator 14 and intended to be secured in rotation with the rotary shaft to slow down.
• the shaft 16 which is provided with splines 161 for fixing the rotor 15 on the axis 16, carries a centrifugal fan 7 for cooling the rotor 15.
• the excitation current generated by the generator 3 is used by coils 20 of the rotor 15 of the retarder 1 to generate an alternating magnetic field.
• the coils 20 are formed by windings of electrical wires around cores 201 forming integral parts of the rotor 15.
• Each core 201 has grooves 202 for receiving the winding, of which FIG. 1 only symbolically shows one so as not to clutter the winding.
• the magnetic field induces the stator 14 of the retarder 1 and generates eddy currents therein, in particular in the lower part of the stator 14 made of a ferromagnetic material.
• the eddy currents being opposed, by their effects, to the cause that gives them the sense, namely the rotational movement of the rotor, the rotational movement of the rotor 15 thus generates a reverse torque, and thus a braking torque.
• the stator 14 is cooled by the cooling jacket 10 which comprises, in addition to the duct 11, inlet and outlet connectors 12 between which the duct 11 extends.
• the lower portion of the stator 14 is an integral part of the jacket of the cooling jacket 10.
• the duct 11 of the cooling jacket 10 which is shown in more detail in FIGS. 4, 5 and 8, is delimited by a radially inner wall 17, a radially outer wall 18, as well as two side walls 21, 22.
• the inner wall 17 is formed the
• the outer wall 18 is an integral part of an element made in one piece of a moldable alloy and forming, in addition to the duct 11, the inlet fitting 12 and the outlet fitting 13.
• the duct 11 has a cross-section at less approximately rectangular.
• the outer wall 18 and the adjacent lateral wall 22 of the duct 11 are integrated in, that is, formed together in a single piece 10A with the portion upper case made of moldable alloy of the cooling jacket 10. And similarly, the inner wall 17 and the adjacent side wall 21 are formed in one piece 10B as the lower part of the stator of a ferromagnetic material.
• the upper 10A and lower 10B parts are assembled with the interposition of two seals 19A and 19B.
• the cooling jacket 10 is traversed by a coolant which is advantageously derived from the cooling circuit of the vehicle.
• the cooling jacket 10 limits heating of the surface of the stator 14, heating generated by the eddy currents of high intensity explained above.
• the cooling jacket 10 advantageously extends over the entire axial length of the stator 14, seen in the direction of the orientation of the axis 16 of the rotor 15, the surface of the chamber 10 has a substantially equal area to the one of the surface of the stator 14 opposite which the outer wall 18 of the cooling jacket is located. The dissipation of the heat of the stator 14 thus takes place over the entire surface of the cylindrical wall of the stator 14 in which the eddy currents are generated.
• FIG. 2 shows the insulation cooling jacket, i.e. without the other components of the retarder.
• the inner wall 17 of the cooling jacket 10 which essentially corresponds to the stator 14 of the retarder 10 is clearly distinguished and forms an inner wall of the duct 11.
• the outer wall 18 of the cooling jacket 10 which essentially corresponds to an outer wall of the duct 11 of the cooling jacket 10 and comprises the inlet connectors 12 and outlet 13 for a cooling fluid.
• FIG. 3 is a perspective view of the outer wall 18 of the cooling jacket 10. This view shows more particularly the circumferential extent of an inlet zone Z1 of the inlet connection 12 and of a departure zone Z2 of the outlet fitting 13.
• the zones Z1 and 22 correspond approximately to a tangential inlet of the cooling fluid via the inlet connection 12 and to a tangential departure of the cooling fluid through the outlet connection 13.
• the inlet and outlet connections 12, 13 are shaped so as to present, all along their length. longitudinal extent, a constant area of their passage section while taking into account the particularities in which a circular section conduit is generally used for the supply and discharge ducts of a cooling circuit, while the cross section of the cooling jacket in the part surrounding the rotary machine to be cooled has a cross-section. generally rectangular.
• FIG. 3 further shows that the arrival zone Z1 of the inlet connection 12 and the departure zone Z2 where the outlet connection 13 begins are separated from each other by an evolutionary wall M shaped in a manner to give the cooling fluid a preferred direction of flow.
• the cooling fluid arrives in the Zl zone with a fairly high speed and pressure and encounters a lower pressure fluid leaving the zone Z2. So that the exchange surface between the incoming flow and the outgoing flow is relatively small and therefore does not promote a significant interaction between the two flows, it could nevertheless occur that the meeting between the two flows creates an area of turbulent turbulence strongly to the effective flow of the coolant.
• the moving wall M separates the arrival zone Z1 from the departure zone 22, the height of the wall M corresponding to the height of the helical circuit 11.
• the wall can also be formed on the inner wall of the cooling jacket.
• Figure 4 shows the mechanical structure of the assembly of the upper part 10A with the inner wall 17 and the lower part 10B with the outer wall 18, of the cooling jacket 10.
• Figure 4 shows more particularly that the two walls 17 and 18 are mounted with a degree of freedom in the axial direction relative to each other.
• This axial clearance makes it possible to absorb the axial differential expansions between the inner 17 and outer 18 walls during the different phases of operation of the retarder and thus makes it possible to guarantee it good durability.
• This axial clearance can reach a few millimeters, but is generally of the order of one to two millimeters.
• a radial clearance of a few tenths of millimeters exists by construction in order to be able to assemble the upper parts 10A and lower 10B.
• This radial clearance, compatible with the differential expansions between the two parts 10A, 10B, is taken up by means of two O-rings 19A, 19B positioned on either side of the cooling jacket 10.
• the outer wall 18 is made of an aluminum alloy and the inner wall 17 of a high yield strength steel.
• the expansion coefficients of these two materials, as well as the thermal stresses, are different, the fact that each part can expand freely with respect to the other makes it possible to avoid internal stresses. Nevertheless, the choice of materials is made in such a way as to obtain compatible axial and radial expansions on the two inner and outer walls 17 and 18.
• the seal between the two inner and outer walls 17 is advantageously obtained by means of two O-rings 19A, 19B in one silicone at high temperature to ensure good thermal resistance, while maintaining a good resistance to the cooling fluid. Special care is given to the surfaces in contact to limit the premature wear of said surfaces and joints.
• the outer wall 18 is provided, on the opposite face of the inner wall 17 and close to the side intended to be in contact with the lateral wall 21. , a partition 181.
• This partition 181 is used to define, together with a shoulder 171 formed at the junction of the inner walls 17 and 21 side, a volume for receiving the O-ring 19A.
• the walls 17 and 18 being mounted with a radial clearance R of the order of a few tenths of a millimeter, the seal 19A is not compressed until crushed.
• the height of the partition 181 is also advantageously determined so as to prevent the seal 19A is, even momentarily, completely crushed, which would remove its elasticity and thus its sealing effectiveness.
• this seal is not necessarily an O-ring. It can equally well be constituted by a flat gasket or a lip seal. According to an alternative embodiment not shown in the drawings, but not outside the scope of the present invention, the walls 17 and 18 are provided with grooves intended to receive together the seal 19A.
• the inner wall 17 is shaped and dimensioned so as to simultaneously, define a volume for receiving the seal 19B and allow axial play A of the order of a few millimeters resulting from temperature differences up to an order of magnitude of some 300 degrees. Due to the essentially axial stress that the seal 19B undergoes, it is advantageously an O-ring. However, it is also conceivable that one uses in its place a lip seal, if the magnitude of the axial clearance A allows it.
• the walls 17 and 18 are mounted, on the side of the side wall 22, also with a radial clearance R corresponding to that provided on the side of the side wall 21.
• the helical duct 11 of the cooling jacket 10 shown in FIG. 5 in an axial view is provided with an inlet connection 12 and a tangential outlet connection 13.
• the "tangential" characteristic indicates that the connectors 12 and 13 are each oriented, the inlet fitting 12 in a circumferential zone of arrival 21 and the outlet connector 13 in a circumferential starting zone Z2 of the duct 11, at least approximately along a tangent T1 passing through the center of zone Z1 and at least approximately along a tangent T2 passing through the center of zone 22.
• the centers of zones Z1 and Z2 are determined by the radii R1 and R2 leading to the circumference of the duct
• the arrival zone Z1 and departure zone Z2 are disposed with an angular offset D of the order of 20 ° to 30 °.
• the arrangement of the inlet connectors 12 and outlet 13 with a relative angular offset between the two, and in particular with a relatively small angular offset as indicated above, corresponds to a configuration considered advantageous for embodiments where the helical duct 11 surrounding the retarder 1 comprises only one turn and where the portion of coolant considered therefore runs, comparatively fast, a single turn and immediately leaves the helical conduit. This results in good cooling over the entire width of the duct 11.
• FIG. 6 represents the duct 11 of a cooling jacket 10 according to the invention with an inlet fitting 12.
• the passage section of the inlet fitting 12 is shown above the latter at four locations different to thus demonstrate the change in the shape of the passage section by keeping the passage area constant.
• FIG. 7 represents, in a manner schematic in a side view, the connector 12 and the beginning of the duct 11.
• the passage section of the inlet fitting 12 is shown next to the latter at three different locations to thereby demonstrate the change of the shape of the passage section keeping the passage area constant.
• the cooling jacket can also be made by a pipe surrounding the stator 14 in the form of a plurality of helical turns or in the form of a plurality of substantially annular conduits. surrounding the stator almost entirely and parallel to each other and respectively connected to a common inlet fitting and a common outlet fitting.
• the solution of the present invention provides valuable assistance: the embodiment of the portion 10A of a moldable material.

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=34949570

Family Applications (1)

Country Status (6)

Families Citing this family (14)

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• 2004
  • 2004-06-30 FR FR0407228A patent/FR2872643A1/fr not_active Withdrawn
• 2005
  • 2005-06-30 EP EP05783998A patent/EP1784908A1/de not_active Withdrawn
  • 2005-06-30 US US11/570,940 patent/US20080284263A1/en not_active Abandoned
  • 2005-06-30 AU AU2005266250A patent/AU2005266250A1/en not_active Abandoned
  • 2005-06-30 WO PCT/FR2005/001662 patent/WO2006010863A1/fr active Application Filing
• 2006
  • 2006-11-27 ZA ZA200609867A patent/ZA200609867B/xx unknown

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