Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/46—Fastening of windings on the stator or rotor structure
  • H02K3/52—Fastening salient pole windings or connections thereto
  • H02K3/521—Fastening salient pole windings or connections thereto applicable to stators only
  • H02K3/522—Fastening salient pole windings or connections thereto applicable to stators only for generally annular cores with salient poles
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K15/00—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
  • H02K15/08—Forming windings by laying conductors into or around core parts
  • H02K15/095—Forming windings by laying conductors into or around core parts by laying conductors around salient poles
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K2203/00—Specific aspects not provided for in the other groups of this subclass relating to the windings
  • H02K2203/12—Machines characterised by the bobbins for supporting the windings

Definitions

• the present invention relates to the field of electric motors and in particular electric motors intended to equip electric bicycles.
• Electric bicycles are becoming more and more popular because of the ease of movement they provide while having reduced energy consumption, environmental impact and cost price.
• the positioning of the electric motor on the bicycle involves space constraints so as to allow the integration of the electric motor without compromising other characteristics of the bicycle.
• the subject of the invention is therefore a coil of a stator for an electric motor comprising:
• a coil forming a tooth of the stator comprising: - a central axis of tubular shape comprising a plurality of grooves arranged on its periphery between a first end of the coil intended to be oriented towards the center of the stator and a second end of the coil intended to be oriented towards the outside of the stator, the grooves being intended to receive a turn of a winding wire wound around the spool,
• winding wire configured to be wound in the form of turns around the coil, the ends of the winding wire being positioned on the side of the first end of the coil so as to allow electrical connections to the center of the stator in which the coil comprises a recess of material extending between the first end and the second end of the spool, said recess of material being configured to receive the winding wire and to allow the passage of the winding wire between the first end and the second end of the spool.
• the presence of an axial recess extending between the first and the second end of the spool makes it possible to position the first connector associated with a first end of the spool and to begin the winding of the winding wire at the level of a groove located at the second end of the coil without creating extra thickness in the winding, which makes it possible to position the two connectors on the same side of the coil and to produce a trapezoidal winding so as to reduce the size of the coil while limiting the risk of short- circuit with an adjacent coil.
• the material recess forms an axial groove extending through the grooves.
• the depth of the material recess is between 0.8 and 1.2 times the diameter of the winding wire, which makes it possible not to create any extra thickness for the winding.
• the spool also comprises a holding pad disposed at the second end of the spool and configured to direct the winding wire coming from the material recess towards a starting groove of the winding of the wire winding.
• the retaining stud ensures the correct positioning of the winding wire and to limit the risk of displacement of the winding wire which could lead to a malfunction of the electric motor.
• the coil also includes a first connector configured to receive the first end of the winding wire and a second connector configured to receive the second end of the winding wire.
• the first and the second connectors are integral with the coil.
• the grooves are inclined with respect to a plane normal to the axis of the coil, the width and the inclination of the grooves being determined so that turns of the winding arranged in two adjacent grooves are adjacent and that the successive turns form a helical winding around the central axis.
• the central axis of the reel has a rectangular section.
• the coil forms a tooth separate from the stator configured to be positioned on a central module of the stator after the winding has been completed.
• the coil comprises an internal portion intended to receive a first number of layers of turns and an external portion intended to receive a second number of layers of turns greater than the first number to form a trapezoidal winding and the at least one of the turns of the last layer of the inner portion is made after the turns of the last layer of the outer portion in order to hold the various turns of the winding in position.
• the present invention also relates to a stator for an electric motor comprising a plurality of coils as described above.
• the coils are connected according to a star connection.
• the present invention also relates to an electric motor comprising a stator as described previously, in which said electric motor is a three-phase brushless motor.
• the present invention also relates to a method for manufacturing a coil of an electric motor stator comprising a coil on which is formed a plurality of grooves intended to receive turns of a winding wire and arranged on the periphery of a central axis of the coil between a first end of the central axis intended to be oriented towards the interior of the stator and a second end of the central axis intended to be oriented towards the exterior of the stator, the coil also comprising a recess for material forming a guide groove of a winding wire between the first end and the second end of the central axis, said method comprising a step of positioning the winding wire in the guide groove before a step of winding the wire winding around the spool.
• the use of the guide groove makes it possible to start winding the winding at the end opposite the connector so that the two connectors can be positioned on the same side of the coil, which makes it possible to reduce the size of the coil.
• the winding wire winding step is completed at one end of the spool and the second end of the winding wire is attached to the level of the first end of the spool.
• FIG.1 shows a schematic perspective view of part of an electric motor
• FIG.2 shows a first schematic perspective view of a coil of a coil of a stator
• FIG.3 shows a second schematic perspective view of a coil of a coil of a stator
• FIG.4 shows a third schematic perspective view of a coil of a coil of a stator
• FIG.5 represents a flowchart of the steps of a method of manufacturing a coil according to the present invention
• FIG.6 shows a schematic sectional view of a coil during a first winding step
• FIG.7 shows a schematic sectional view of a coil during a second winding step
• FIG.8 shows a schematic sectional view of a coil during a third winding step
• FIG.9 shows a schematic sectional view of a coil during a fourth winding step
• FIG.10 shows a schematic sectional view of a coil during a fifth winding step
• FIG.11 shows a schematic sectional view of a coil during a sixth winding step
• FIG.12 shows a schematic sectional view of a coil at the end of the winding
• FIG.13 shows a schematic perspective view of a rotor with separated teeth
• FIG.14 represents a flowchart of the manufacturing steps of a stator.
• first element or second element as well as first parameter and second parameter or else first criterion and second criterion, etc.
• first criterion and second criterion etc.
• it is a simple indexing to differentiate and name elements or parameters or criteria that are close, but not identical.
• This indexing does not imply a priority of one element, parameter or criterion with respect to another and such denominations can easily be interchanged without departing from the scope of the present description.
• This indexation does not imply an order in time either, for example to assess such and such a criterion.
• FIG. 1 represents a diagram of part of an electric motor 1 comprising a stator 3 and a rotor 5.
• the electric motor 1 is for example a brushless three-phase electric motor, but the present invention is not limited to this type of electric motor 1 .
• Such an electric motor 1 is particularly suitable for being placed in an electric bicycle, but the present invention is not limited to this application.
• the stator 3 comprises a central module 7 and a plurality of teeth formed by coils 9 and arranged around the central module 7.
• the coils 9 form, for example, separate teeth configured to be fixed on the central module 7.
• the central module 7 comprises for example connection frames 11 configured to connect the various coils 9 according to a predefined electrical diagram, for example according to a star or delta connection.
• connection frames 11 comprise for example connection tabs extending radially and the coils 9 comprise for example complementary connectors 13a and 13b.
• the connectors 13a and 13b are configured to receive the ends of the winding wires 29 and to be positioned on the connection lugs to ensure an electrical connection between the ends of the winding wires 29 and the connection frames 11 .
• FIG. 2 represents a schematic view in perspective of a spool 17 of a spool 9.
• the spool 17 forms the support on which the winding wire 29 is wound to form the spool 9.
• the spool 17 comprises a central axis 19 of tubular shape.
• the section of the central axis 19 is rectangular but other section shapes can also be used.
• the central axis 19 comprises a plurality of grooves 21 arranged around its periphery and configured to receive turns of winding wire 29 to enable them to be held in position along the central axis 19.
• the grooves 21 extend in a direction substantially perpendicular to the axial direction of the central axis 19.
• the grooves 21 may present an angle with respect to the direction perpendicular to the axial direction to allow the winding of the turns in a helical manner along the central axis 19.
• the width of the grooves 21 is determined so that two consecutive turns of the winding are adjacent.
• the grooves 21 are formed between a first end 17a of the reel 17 also corresponding to a first end 9a of the reel 9 and a second end 17b of the reel 17 also corresponding to a second end 9b of the reel 9.
• the first end 17a of the reel 17 is intended to be oriented towards the center of the stator 3 and comprises a first flange 23 for retaining the winding wire 29.
• the second end 17b of the coil 17 is intended to be oriented towards the outside of the stator 3 and comprises a second flange retainer 25 of the winding wire 29.
• the coil 17 can also comprise a first connector 13a configured to receive a first end of the winding wire 29 corresponding for example to the initial end of the winding wire 29, that is to say the end connected to a turn of the first layer (i.e. the layer in contact with the grooves 21 of the coil 17) and a second connector 13b configured to receive a second end of the winding wire 29 corresponding for example to the final end of the winding wire 29, i.e. i.e. the end connected to a turn of the last layer (i.e. the peripheral layer).
• a first connector 13a configured to receive a first end of the winding wire 29 corresponding for example to the initial end of the winding wire 29, that is to say the end connected to a turn of the first layer (i.e. the layer in contact with the grooves 21 of the coil 17)
• a second connector 13b configured to receive a second end of the winding wire 29 corresponding for example to the final end of the winding wire 29, i.e. i.e. the end connected
• the first 13a and the second 13b connectors are located on the internal side of the coil 17, that is to say the side of the coil 17 configured to be oriented towards the inside of the stator 3 in the mounted state. of the stator 3.
• the first 13a and second 13b connectors are for example fixed on the first retaining collar 23 and come for example in one piece with the rest of the coil 17.
• the spool 17 comprises a material recess 27 extending in a substantially axial direction of the spool 17, that is to say in a direction substantially perpendicular to the direction of the furrows 21 .
• the material recess 27 is configured to receive the winding wire 29.
• the material recess 27 is configured to extend from the first end 17a of the coil and in particular from the first connector 13a to the second end 17b of the coil 17 in order to form an axial groove allowing the passage of the winding wire 29 from the first end 17a to the second end 17b of the spool 17 before the start of the winding of the winding wire 29.
• Such a passage of the winding wire in an axial groove makes it possible to position the first connector 13a on the side of the first end 17a of the coil 17 and to start the winding of the winding at the level of a groove 21 located at the second end 17b of the spool 17 without increasing the size of the spool 9.
• the width of the material recess 27 is for example between 1 and 1.2 times the diameter of the winding wire 29 and the depth of the material recess 27 is for example between 0.6 and 1.2 times the diameter of the winding wire 29.
• the spool 17 may also include a guide stud 31 made at the second end 17b of the spool 17 and close to the end of the material recess 27 to allow the winding wire 29 to be guided from the material recess 27 towards the start groove of the rolling.
• a guide stud 31 made at the second end 17b of the spool 17 and close to the end of the material recess 27 to allow the winding wire 29 to be guided from the material recess 27 towards the start groove of the rolling.
• the guide stud 31 may have the shape of a hook on which the winding wire 29 is wound.
• the end of the hook makes it possible to hold the winding wire 29 against the central axis 19 of the reel 17 and the base of the hook makes it possible to maintain the winding wire in an axial direction.
• the winding wire 29 is configured to extend from the first connector 13a in the material recess 27 as far as the holding stud 31 around which it wraps to be positioned in the starting groove.
• the coil 9 therefore also includes a winding wire 29 configured to be wound around the coil 17 to form the winding.
• a winding wire 29 configured to be wound around the coil 17 to form the winding.
• Different types of windings can be made and in particular a trapezoidal winding in which the number of layers of turns is not the same over the entire axial length of the coil 17.
• the recess of material 27 can be used for other types of winding in which the winding wire 29 must be transferred from a first end 17a to a second end 17b of the spool 17 before winding.
• the coil 17 and therefore the coil 9 comprise for example an internal portion 9i, 17i intended to receive a first number of layers of turns, for example two layers, and an external portion 9th, 17th intended to receive a second number of layers of turns greater than the first number, for example three layers. It is also possible to design a coil comprising a number of parts greater than two, for example three parts, each having a different number of layers of turns.
• first 13a and second 13b connectors intended to receive the ends 29a and 29b of the winding wire 29 being located at the first end 17a of the coil 17, that is to say the end intended to be oriented towards the center of the stator 3 in the mounted state, it is necessary to finish the winding on the side of the first end 17a of the coil 17.
• the winding of the winding wire 29 is started at the level of a groove 21 corresponding to the extreme groove on the side of the second end 17b of the reel 17.
• the present invention also relates to a method of manufacturing a coil as described above.
• FIG. 5 represents a flowchart of the steps of the manufacturing process.
• the first step 101 concerns the positioning of the first end 29a of the winding wire 29 in the first connector 13a.
• the second step 102 relates to the positioning of the winding wire 29 in the material recess 27. If the reel 17 includes a holding stud 31, step 102 also includes the positioning of the winding wire 29 around the holding stud 31 up to the starting groove as represented in FIG. 6.
• the circles represent the position of the various turns at the end of the winding and the dotted lines represent the position of the grooves 21.
• the coil 17 comprises seven grooves 21 and the outer part 9a of the reel 9 comprises four grooves 21.
• the starting groove corresponds to the first groove (starting from the first end 17a of the reel 17).
• the third step 103 relates to the winding of the first layer of turns, that is to say the layer of turns in contact with the grooves 21 of the reel 17.
• the winding is carried out from the starting groove going towards the first end 17a of the spool 17 following the adjacent grooves 21 as shown in Figure 7.
• the fourth step 104 relates to the winding of the second layer of turns of the inner portion 17i of the coil 17.
• the coil reaches the extreme groove located at the first end 17a of the coil 17, at the end of step 103, the The winding begins the second layer of turns of the internal portion 17i of the spool 17 by moving towards the second end 17b of the spool 17, the winding being carried out over the turns formed during step 103.
• the turns of the second layer are positioned in the pseudo-groove formed at the interface between two adjacent turns of the first layer.
• at least one location of a turn that is to say one of the pseudo-grooves, is left free during the winding of the turns of the second layer of the internal portion 17i as represented in FIG. 8
• the location left free is for example located in the middle of the internal portion 17i. If several slots are left free, the slots left free are distributed between the turns of the internal portion 17i, for example one slot out of two.
• the fifth step 105 relates to the winding of the turns of the second layer of the outer portion 17th of the coil 17.
• the sixth step 106 concerns the winding of the turns of the third layer of the external portion 17e of the spool 17.
• the winding returns to the first end 17a to form the third layer of turns of the outer portion 17e as shown in Figure 10.
• the seventh step 107 relates to the winding of one or more turns in the slots left free in the second layer of the internal portion 17i of the coil 17 during step 104 as represented in FIG. 11. These turns correspond to turns of the second layer of the internal portion 17i but are made after the turns of the third layer of the external portion 17e.
• the eighth step 108 concerns the positioning of the second end 29b of the winding wire 29 in the second connector 13b.
• step 107 the second end 29b of the winding wire is attached to the second connector 13b as shown in Figure 12.
• This step 108 may include cutting the winding wire 29 to train the second end 29b of the winding wire 29. The last turn or turns are held in position by the adjacent turns of the second layer of the internal portion 17i.
• the number of turns per layer and the number of layers may be different from the embodiment presented previously so that the starting groove of the winding can also be the extreme groove located on the side of the first end 17a of the coil 17
• the spool 17 may not include a material recess 17, nor a holding stud 31. It is also possible to use solutions other than the material recess 27 to allow the thread to pass. winding 29 from the first end to the second end of the coil 17 before winding the turns.
• process steps may be optional or additional steps may be added.
• Such a manufacturing method makes it possible to obtain a trapezoidal winding whose ends are located on the small side of the trapezium and whose angle, denoted a in FIG. 12, of the winding wire 29 at the level of the last turn of the last layer is reduced which makes it possible to ensure that this last turn is maintained in position and to avoid a risk of the winding wire 29 of the last turn slipping towards the short side of the trapezium which could lead to a short circuit with the winding 29 of the adjacent coil 9.
• the present invention also relates to a stator 3 comprising a plurality of teeth formed by coils 9 such as the coil 9 described previously.
• the coils 9 form separate teeth configured to be positioned on a central module 7 as shown in Figure 1.
• Figure 13 shows an example of a stator 3 with separate teeth.
• the stator 3 also includes a yoke 19 configured to be positioned around the coils 9.
• the present invention also relates to a method of manufacturing a stator 3 as described above.
• FIG. 14 represents a flowchart of the steps of the manufacturing method of such a stator 3.
• the first step 201 concerns the making of the coils 9 as described above.
• the winding of the winding wire 29 is for example carried out by a robot and the coils 9 can all be identical.
• the second step 202 relates to the connection of the coils 9 forming separate teeth on the central module 7 so that the connection tabs of the connection frames 11 are inserted into the first 13a and second 13b connectors to ensure the connection between the coils 9 and connecting frames 11 .
• a connection tab being configured to come into contact with one end of the winding wire 29 at the level of a first connector 13a or a second connector 13b. The fixing is done for example by snapping the coils 9 onto the central module 7.
• the third step 203 concerns the positioning of the yoke 19 around the coils 9 forming the separate teeth.
• the yoke 19 being positioned on the coils 9 by axial translation.
• the present invention also relates to an electric motor 1 comprising a stator 3 as described above and a rotor 5 comprising a plurality of poles, for example 10 or 14 poles, configured to interact with the coils of the stator 3 to cause the rotation of the rotor 5.
• stator 3 with separate teeth configured to be fixed on a central module 7 comprising the connection frames ensuring the electrical connections between the coils 9 via connectors provided on the coil 17 and a trapezoidal winding make it possible to obtain a stator 3 and therefore an electric motor 1 having a reduced size which can thus be easily integrated into an electric bicycle in particular.
• a configuration allows a simple and rapid method of manufacturing the electric motor.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Manufacture Of Motors, Generators (AREA)
• Windings For Motors And Generators (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=78332967

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• 2021
  • 2021-09-30 FR FR2110375A patent/FR3127656B1/fr active Active
• 2022
  • 2022-09-30 US US18/697,327 patent/US12614946B2/en active Active
  • 2022-09-30 EP EP22797370.8A patent/EP4409733A1/de active Pending
  • 2022-09-30 WO PCT/EP2022/077320 patent/WO2023052605A1/fr not_active Ceased
  • 2022-09-30 CN CN202280071157.6A patent/CN118140386A/zh active Pending

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