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
  • H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
  • H02K2213/03—Machines characterised by numerical values, ranges, mathematical expressions or similar information

Definitions

• the present invention relates to a rotating electrical machine provided with a cooling chamber with an optimized configuration.
• the invention relates to the field of rotating electrical machines such as electric motors, alternators, or alternator-starters which are reversible electrical machines that can operate in a motor mode or a generator mode.
• a rotating electrical machine comprises a rotor integral with a driving and/or driven shaft and a stator which surrounds the rotor with the presence of an air gap.
• the stator is carried by a casing formed by two bearings provided with bearings for the rotational mounting of the rotor shaft.
• the rotor may comprise a body formed by a stack of sheet metal sheets held in the form of a package by means of a suitable fixing system.
• the rotor comprises poles formed for example by permanent magnets housed in cavities formed in the magnetic mass of the rotor.
• the poles are formed by coils wound around the arms of the rotor.
• the stator comprises a body consisting of a stack of thin sheets forming a crown, the inner face of which is provided with slots open inwardly to receive phase windings. These windings pass through the notches and form buns protruding from either side of the body of the stator.
• the phase windings are obtained for example from a continuous wire covered with enamel or from conductive elements in the form of pins connected together by welding.
• the polyphase electrical machine comprises a stator winding consisting of several preformed coils mounted around the teeth of the stator via a coil insulator.
• the heat generated by the flow of current through the winding of the stator can be evacuated to a cooling chamber extending circumferentially around the stator and in which a cooling liquid circulates.
• a cooling chamber in which the coolant inlet and the outlet are angularly offset relative to each other, the flow rates of coolant circulating in the cooling zones are extending on either side of the inlet are generally unbalanced, so that the cooling is not homogeneous.
• the document JPS5983557 thus illustrates in the figures the presence of cooling fins on only one side of the cooling circuit. Indeed, these fins extend radially and in the direction of circulation of the coolant on one side of the cooling circuit.
• the coolant inlet and outlet being angularly offset from each other by 180 degrees, such a configuration limits the coolant flow rate on the side of the circuit comprising the fins so that this side will be less well cooled.
• stator provided with a stator body and a winding
• cooling chamber extending circumferentially around the stator body, said cooling chamber having a radially inner face and a radially outer face,
• first cooling zone extending along a first circumferential portion of the cooling chamber between the cooling liquid inlet and the cooling liquid outlet
• a second cooling zone extending along a second circumferential portion of the cooling chamber between the coolant inlet and the coolant outlet
• the first circumferential portion and the second circumferential portion extending on either side of the cooling inlet so as to cover an entire circumference of the chamber cooling zone
• the first cooling zone and the second cooling zone having hydraulic resistances adapted so that a first flow rate of cooling liquid circulating in said first cooling zone is proportional to a first length of the first circumferential portion of the chamber cooling and that a second flow rate of cooling liquid circulating in said second cooling zone is proportional to a second length of the second circumferential portion of the cooling chamber.
• a hydraulic resistance corresponds to the pressure drop undergone by the coolant inside a cooling zone.
• the hydraulic resistance can be modified in particular by adapting a geometry of the cooling zones, in particular a coolant passage section, and/or a number and a geometry of fins cooling, and/or a number and a geometry of low walls arranged inside a cooling zone. The greater the number of fins and/or low walls (of the same dimensions) inside a cooling zone, the greater the pressure drop and therefore the hydraulic resistance.
• the invention thus makes it possible, thanks to the adaptation of the hydraulic resistances according to the lengths over which the cooling zones extend, to obtain efficient and homogeneous cooling along the entire circumference of the stator of the rotating electrical machine.
• the first length of the first circumferential portion of the cooling chamber and the second length of the second circumferential portion of the cooling chamber are different.
• the second length is less than or equal to 0.8 times the first length, in particular less than or equal to 0.7 times the first length.
• the first coolant flow rate inside the first cooling zone is greater than or equal to 0.7*[(L1)/(L1+L2)]*Q and less than or equal to 1.3*[(L1)/(L1 +L2)]*Q
• the first coolant flow rate is proportional to the first length of the first circumferential portion of the cooling chamber according to a first proportionality coefficient and the second coolant flow rate is proportional to the second length of the second circumferential portion of the cooling chamber according to a second coefficient of proportionality, the second coefficient of proportionality being greater than or equal to 0.9 times the first coefficient of proportionality and less than 1.1 times the first coefficient of proportionality, in particular the second proportionality coefficient being greater than or equal to 0.95 times the first proportionality coefficient and less than 1.05 times the first proportionality coefficient.
• the first cooling zone and/or the second cooling zone comprise at least one cooling fin.
• the cooling fin or fins extend radially and along a portion of the circumference of the cooling chamber.
• the first cooling zone and the second cooling zone comprise a different number of cooling fins.
• the first cooling zone and the second cooling zone comprise cooling fins having thicknesses of different sizes.
• the first cooling zone and/or the second cooling zone comprise at least one low wall extending radially and axially with respect to an axis of the electric machine.
• cooling liquid passage space between a free end of the low wall and a face of the cooling chamber arranged opposite the low wall.
• the first cooling zone and/or the second cooling zone comprise at least one first low wall formed in the radially inner face of the cooling chamber, so that there is a space coolant passage between the free end of the first wall and the radially outer face of the cooling chamber.
• the first cooling zone and/or the second cooling zone comprise at least one second low wall made in the radially outer face of the cooling chamber, so that there is a space coolant passage between the free end of the second low wall and the radially inner face of the cooling chamber.
• the first cooling zone and/or the second cooling zone comprise a plurality of first low walls and second low walls formed alternately in the radially inner face and the radially outer face of the cooling chamber. cooling.
• the first cooling zone and the second cooling zone comprise a different number of low walls.
• the first cooling zone and the second cooling zone have cooling liquid passage sections of different geometries.
• the coolant passage sections of the first cooling zone and of the second cooling zone have different radial heights.
• FIG. 1 is a perspective view of a rotary electrical machine according to the present invention
• FIG. 2 is a cross-sectional view of the rotating electrical machine according to the present invention.
• FIG. 3 is a cross-sectional view of the bearings of the rotary electrical machine according to the invention defining an annular cooling chamber around the stator;
• Figures 4a and 4b illustrate different embodiments of cooling fins extending inside the cooling chamber of the electric machine according to the invention;
• FIG. 5 illustrates an embodiment of low walls extending inside the cooling chamber of the electric machine according to the invention.
• Figures 1 and 2 show a rotating electrical machine 10 comprising a housing 1 1 in which are mounted a fixed stator 12 and a rotor 13.
• the rotor 13 is rotatably mounted relative to two bearings 15, 16 of the housing 1 1
• the electric machine 10 has an axis X corresponding to the axis of rotation of the rotor 13 as well as to the axis of the stator 12.
• the rotor 13 comprises a body formed by a stack of sheet metal sheets held in the form of a package by means of a suitable fastening system comprising, for example, rivets.
• the rotor 13 comprises poles formed for example by permanent magnets housed in cavities arranged in the magnetic mass of the rotor 13.
• the poles are formed by coils wound around the arms of the rotor 13.
• the rotor may be a claw rotor called the “claw pole rotor” type in English.
• the stator 12 comprises a body 14 consisting of a stack of thin sheets forming a ring, the inner face of which is provided with notches open inwards to receive phase windings (not shown in the figure 2).
• the phase windings are obtained for example from a continuous wire covered with enamel or from conductive elements in the form of pins connected together by welding.
• the polyphase electric machine 10 comprises a stator winding 12 consisting of several preformed coils mounted around the teeth of the stator 12 via a coil insulator.
• the bearings 15, 16 of the housing 11 define a cooling chamber 18 extending circumferentially around the stator body 14.
• the cooling chamber 18 as well as bearings 15, 16 are coaxial with axis X.
• the first bearing 15 comprises a transverse portion 19 extending transversely to the axis X.
• This transverse portion 19 is provided centrally with a housing 20 receiving a bearing 21 for the rotational mounting of one end of a shaft carrying the rotor 13.
• the first bearing 15 further comprises a skirt 22 generally having a tubular shape extending axially from the outer periphery of the transverse portion 19.
• the second bearing 16 comprises a transverse portion 24 extending transversely relative to the axis X.
• This transverse portion 24 is centrally provided with a housing 25 receiving a bearing (not shown) for mounting rotation of one end of the shaft carrying the rotor 13.
• the second bearing 16 further comprises a skirt 26 generally having a tubular shape extending axially from the outer periphery of the transverse portion.
• the skirt 26 of the second bearing 16 has an internal diameter slightly greater than the external diameter of the skirt 22 of the first bearing 15.
• one of the bearings 15, 16 comprises the two skirts 22, 26 and is closed by the other bearing 15 , 16 comprising only a transverse portion forming a cover for the cooling chamber 18.
• the bearings 15, 16 are one-piece parts.
• a bearing 15, 16 may be formed from a tubular portion 22, 26 which is distinct and assembled with the transverse portion 19, 24.
• the skirt 26 of the second bearing 16 is arranged around the skirt 22 of the first bearing 15 so as to form the cooling chamber 18 in which a cooling liquid circulates.
• the cooling liquid may for example be water with an anti-freeze.
• the cooling liquid may consist of an oil or any other heat transfer liquid suitable for the application.
• the stator body 14 may be mounted shrunk inside the space delimited by the skirt 22 of the first bearing 15. The outer periphery of the stator body
• the cooling chamber 18 has a radially inner face 29 corresponding to the outer periphery of the skirt 22 of the first bearing
• a first cooling zone 34.1 extends along a first circumferential portion 35.1 of the cooling chamber 18 between the coolant inlet 31 and outlet 32.
• a second cooling zone 34.2 extends along a second circumferential portion 35.2 of the cooling chamber 18 between the inlet 31 and the outlet 32 of coolant.
• the first circumferential portion 35.1 and the second circumferential portion 35.2 extend on either side of the coolant inlet 31 so as to cover an entire circumference of the cooling chamber 18.
• the first cooling zone 34.1 and the second cooling zone 34.2 have hydraulic resistances adapted so that a first flow rate Q1 of coolant flowing in said first cooling zone 34.1 is proportional to a first length L1 of the first circumferential portion 35.1 of the cooling chamber 18 and that a second flow rate Q2 of cooling liquid circulating in said second cooling zone 34.2 is proportional to a second length L2 of the second circumferential portion 35.2 of the cooling chamber 18.
• the first coolant flow rate Q1 is proportional to the first length L1 of the first circumferential portion of the cooling chamber 18 according to a first coefficient of proportionality and the second flow rate Q2 of cooling liquid is proportional to the second length L2 of the second circumferential portion of the cooling chamber according to a second coefficient of proportionality, the second coefficient of proportionality being greater than or equal to 0.9 times the first coefficient of proportionality and less than 1.1 times the first coefficient of proportionality, in particular the second coefficient of proportionality being greater than or equal to 0.95 times the first coefficient of proportionality and less than 1.05 times the first coefficient of proportionality.
• the first length L1 of the first circumferential portion 35.1 of the cooling chamber 18 and the second length L2 of the second circumferential portion 35.2 of the cooling chamber 18 may be different.
• the second length is less than or equal to 0.8 times the first length, in particular less than or equal to 0.7 times the first length.
• a hydraulic resistance corresponds to the pressure drop undergone by the coolant inside a cooling zone.
• the hydraulic resistance can be modified in particular by adapting a geometry of the cooling zones 34.1, 34.2 in particular a coolant passage section, and/or a number and a geometry of cooling fins, and/or a number and geometry of low walls arranged inside a cooling zone. The greater the number of fins and/or low walls (of the same dimensions) inside a cooling zone 34.1, 34.2, the greater the pressure drop and therefore the hydraulic resistance.
• the hydraulic resistances are adapted, so that the first flow rate Q1 of coolant inside the first cooling zone 34.1 is greater than or equal to 0.7*[(L1)/(L1 +L2)]*Q and less than or equal to 1.3*[(L1)/(L1 +L2)]*Q,
• L1 being the first length of the first circumferential portion 35.1 of the cooling chamber 18, L2 being the second length of the second circumferential portion
• the flow rate Q2 of the coolant inside the second cooling zone 34.2 is greater than or equal to 0.7*[(L2)/(L1+L2)]*Q and less than or equal at 1.3*[(L2)/(L1 +L2)]*Q.
• the first cooling zone 34.1 and the second cooling zone 34.2 comprise a plurality of cooling fins 38.
• Each cooling fin 38 extends radially and along a portion of the circumference of the cooling chamber 18 in the direction of flow of the liquid. This type of fins 38 makes it possible to increase the heat exchange surface without considerably increasing the pressure drops.
• the first cooling zone 34.1 and the second cooling zone 34.2 comprise a different number of cooling fins 38.
• the number of cooling fins 38 may be greater in the cooling zone 34.1 s' extending over the shortest circumferential portion 35.1 in order to increase the hydraulic resistance in this zone.
• the fins 38 are made in the radially inner face 29 of the cooling chamber 18.
• the fins 38 may be made in the radially outer face 30 of the cooling chamber 18.
• the fins 38 of the first cooling zone 34.1 and the fins 38 of the second cooling zone 34.2 are of the same thickness L3.
• the thickness L3 of a fin 38 is measured at the level of a central zone of the fin 38 in an axial direction, that is to say in the direction of the X axis of the electric machine 10.
• the thickness L3 of a fin 38 is measured at half a radial extension length of the fin 38.
• first cooling zone 34.1 and the second cooling zone 34.2 comprise fins 38 having thicknesses L3 of different sizes.
• the first cooling zone 34.1 and the second cooling zone 34.2 comprise the same number of fins 38, a thickness L3 of the fins 38 being greater in the cooling zone 34.1, 34.2 having the circumferential portion 35.1, 35.2 more great length so as to leave less space between the fins 38.
• the first cooling zone 34.1 and / or the second cooling zone 34.2 may include at least a first wall 40 extending radially and axially relative to the axis X of the electric machine 10.
• three low walls 40 are formed in the radially inner face 29 of the cooling chamber 18, so that there is a cooling liquid passage space between the free end of each low wall 40 and the radially outer face 30 of the cooling chamber 18.
• the number and the configuration of the low walls 40 could be adapted according to the desired hydraulic resistance to obtain the above relations defining the flow rates Q1 and Q2.
• the first cooling zone 34.1 and/or the second cooling zone 34.2 may include at least one second low wall 40' formed in the radially outer face 30 of the cooling chamber 18, so that there is a coolant passage space between the free end of the second low wall 40' and the radially inner face 29 of the cooling chamber 18.
• first cooling zone 34.1 and/or the second cooling zone 34.2 comprise a plurality of first low walls 40 and second low walls 40' formed alternately in the radially inner face 29 and the radially outer face 30 of the cooling chamber 18.
• the first cooling zone 34.1 and the second cooling zone 34.2 may include the same number or a different number of low walls 40, 40'.
• the low walls 40, 40' can have a length L6 in the direction of the X axis of the machine 10 equal to the length of the first and second cooling zones 34.1, 34.2 in the direction of the X axis.
• the coolant passage sections in the first cooling zone 34.1 and in the second cooling zone 34.2 have the same geometry, in particular the same length L4 measured axially in the direction of the X axis and the same height L5 measured radially to the X axis.
• first cooling zone 34.1 and the second cooling zone 34.2 may have cooling liquid passage sections of different geometries.
• the coolant passage sections of the first cooling zone 34.1 and of the second cooling zone 34.2 may have different heights L5.
• the coolant passage sections of the first cooling zone 34.1 and of the second cooling zone 34.2 may have different lengths L4.
• cooling fins 38 and/or low walls 40 may be formed in the external face of the stator body 14.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Motor Or Generator Cooling System (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=80448886

Family Applications (1)

Country Status (3)

Families Citing this family (1)

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• 2021
  • 2021-12-16 FR FR2113644A patent/FR3131130A1/fr active Pending
• 2022
  • 2022-12-15 WO PCT/EP2022/086173 patent/WO2023111188A1/fr not_active Ceased
  • 2022-12-15 EP EP22835063.3A patent/EP4449591A1/de active Pending

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