Classifications

• • 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
  • H02K1/14—Stator cores with salient poles
  • H02K1/146—Stator cores with salient poles consisting of a generally annular yoke with salient poles
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
  • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
  • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
  • H02K21/16—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures having annular armature cores with salient poles
• • 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
  • H02K1/16—Stator cores with slots for windings
  • H02K1/165—Shape, form or location of the slots
• • 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
  • H02K11/30—Structural association with control circuits or drive circuits
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
  • H02K29/03—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
  • H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
  • H02K7/116—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
  • H02K2201/15—Sectional machines
• • 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 three-phase electric motor, of small size and reduced mass, intended in particular to drive a reduction gear with several stages housed in a housing where the stator part is integrated in a way allowing good organization of the other components (cogwheels, electronic circuit).
• the stator part has two angular sectors alpha-1 and alpha-2, of respective radii RI and R2 with RI different from R2, comprising wide teeth and narrow teeth respectively extending radially from an annular crown.
• the wide teeth have a width greater than or equal to twice the width of the narrow teeth, in that the notch width is greater than the width of a narrow tooth.
• the angular sector alpha-1 is less than 220° and comprises at least three windings.
• Patent EP3326263 is also known, describing another geared motor solution consisting of a housing comprising a brushless motor having at least two electrical phases, a rotor rotating around an axis, and consisting of a stator assembly having at least two poles each carrying coils whose winding axes are spaced apart by a mechanical angle of less than 180° and extend radially.
• the object of the present invention is to remedy this drawback and relates in its most general sense to a three-phase electric motor, formed by a stator part excited by three electric coils and by a magnetized rotor, the stator part having teeth extending radially characterized in that the stator part comprises: three consecutive wound teeth, each carrying a coil, in a first angular sector, one to three complementary non-wound teeth, in a second angular sector complementary to said first angular sector.
• said non-coiled teeth are configured to adjust the torque without current of said three coiled teeth to a predetermined reference value.
• the angular width, the length, and possibly the shape, of said unwound teeth are adjusted so as to sculpt the torque curve without current of the three-phase electric motor, to favor regularity and smoothness or a more or less stiff indexing of the torque without current.
• the angular width, the length and possibly the shape of said unwound teeth are adjusted so as to balance the radial magnetic forces acting between the rotor and the teeth of the stator.
• the angular difference between two consecutive wound teeth is 60°.
• the stator has six teeth, with three uncoiled teeth with a gap of 60°, diametrically opposed to said coiled tooth.
• the stator has five teeth, with an unwound tooth on either side of said first angular sector, with a difference of 60° between the unwound tooth and the consecutive wound tooth.
• the stator has four teeth, with a non-coiled tooth diametrically opposed to the central coiled tooth.
• the length of the coils measured radially and less than the diameter of the rotor, to facilitate insertion.
• the stator is made in two parts to be able to insert long coils.
• the electric motor comprises three unwound teeth separated by an angle of 60°, each of the unwound teeth being diametrically opposed to one of said wound teeth.
• the electric motor comprises two non-coiled teeth located in the second angular sector, the angle formed between each non-coiled tooth and the adjacent coiled tooth being identical.
• the electric motor comprises a single unwound tooth, said unwound tooth being diametrically opposed to the central wound tooth.
• the stator has a cutout between said unwound teeth, the space thus freed up making it possible to accommodate a magneto-sensitive probe for measuring the position of the rotor.
• the length of the coils measured radially is less than the diameter of the rotor.
• the stator is made of it in two or more parts.
• the rotor has 2 N pairs of magnetic poles, N being a natural number less than or equal to 2.
• Geared motor provided with a housing comprising a three-phase electric motor, as well as a motion transformation.
• Geared motor with a housing also comprises control electronics having the means for controlling said three-phase electric motor.
• FIG. 1 shows a perspective view of a first embodiment
• FIG. 1 shows a front view of a first embodiment
• FIG. 4 represents a view of a stator plate of a first embodiment
• FIG. 5 represents a view of a stator plate of a variant of the first embodiment having unequal teeth
• FIG. 6c Figures 6a, 6b, 6c represent the typical torque curves according to the first example of optimized embodiment
• FIG. 7 shows a perspective view of a third embodiment
• FIG. 8c Figures 8a, 8b, 8c represent the typical torque curves according to the third example of optimized embodiment
• FIG. 9 represents a perspective view of an alternative embodiment of a stator according to the invention.
• FIG. 10 represents a perspective view of different rotor variants according to the invention.
• FIGURE 11 shows a perspective view of an alternative embodiment of a stator according to the invention
• FIGURE 12 Figure 12 shows a perspective view of the coupling of the invention to a reducer
• Figure 13 shows a perspective view of a coupling variant of the invention to a reducer
• FIG. 14 shows a perspective view of a coupling variant of the invention to a reducer
• FIG. 15 shows a perspective view of the variant shown in Figure 14 and integrated into the housing of a geared motor
• FIG. 16 represents a perspective view of an alternative embodiment according to the invention provided with a rotor with 2 pairs of poles,
• FIG. 17 represents a perspective view of an alternative embodiment according to the invention provided with a stator having a single unwound tooth
• FIG. 18 shows a simulation of the magnetic forces on each of the teeth for two different widths of the unwound teeth
• FIG. 19 represents a simulation of the resultant of the magnetic forces applied to the stator for two different widths of the unwound teeth.
• the present invention therefore aims to provide a motor, intended in particular to equip a geared motor, which is economical and robust, suitable for large series, and comprising for this a polyphase electric motor allowing easy integration with a reducer or a motion transformation system, respecting all the constraints imposed in terms of external dimensions and mass.
• the space between the teeth is insufficient with the stator architectures of the prior art and does not make it possible to accommodate enough copper in the slots.
• the coil bodies have a non-negligible width compared to the size of the motor and since they cannot be reduced for reasons of moldability and dielectric strength. to be guaranteed between the coils and the stator laminations, the space available for the copper must be increased.
• the change to a lower number of teeth proposed by the invention makes it possible to increase the volume of copper available. Since the coil body remains of constant volume, the ratio of copper volume to volume of the coil body is therefore favorably impacted.
• the solution which is the subject of the invention consists in choosing a structure of three consecutive wound teeth, to which are added one to three unwound teeth, i.e. a total of 4 to 6 teeth in combination with a rotor fitted with a maximum of 4 pairs of poles, the teeth being spaced at 60° or 120° from each other.
• the winding factor of a 6-tooth 4-pair-of-pole structure being magnetically unfavorable in comparison with the previously mentioned 12-tooth 5-pair-of-pole structures, the person skilled in the art will not naturally choose it unless the bulk constraint is strong enough.
• the motor is supplied with only 3 coils (out of a maximum of 6 that it could carry) because this makes it possible to reduce the total volume of the coil body, and therefore maximizes that of copper, and greatly simplifies the electrical connections.
• the magnetic solution combining a stator having wound teeth mechanically separated by 60° and a rotor having 4 pairs of poles is not trivial because this configuration has a torque without current of low harmonic rank and therefore of high amplitude.
• the invention proposes to solve this problem by choosing specific angular tooth widths.
• the stator structure is asymmetrical, all the coils being distributed over 3 teeth located in the same angular sector less than 180°.
• the complementary angular sector has one, two or three bare teeth, that is to say devoid of coils, so as to counterbalance the magnetic forces.
• First example of realization Figures 1 to 4 correspond to a first embodiment of a variant with six teeth (1 to 6). Three consecutive teeth (1 to 3) are wound, with coils respectively (11 to 13) supported by an insulating core (21 to 23), forming an angle of 60° between them, completed by three teeth (4 to 6) more short and uncoiled.
• the teeth extend radially with respect to an annular peripheral zone (10).
• the stator (30) is formed in known manner by a stack of sheets (20) cut from a sheet of ferromagnetic metal.
• the coils (11 to 13) are mounted on a core (21 to 23) having contacts (31 to 33; 41 to 43) of the “pressfit” type allowing connection with a printed circuit.
• the angular width, a 2 , and the length of the unwound teeth (4 to 6), and possibly their shape, are adjusted according to the desired behavior in terms of torque without current, which can favor regularity and smoothness ( "smoothness") or a more or less steep indexing. These characteristics can be determined empirically, by successive adjustments of a rotor prototype, or by modeling the torque without current. For a motor having 6 teeth successively separated by a mechanical 60° and in combination with a rotor having 4 pairs of poles, the torque without current, C 0 , can be minimized by choosing teeth having a frontal end of angular spreading identical, to Q , and of a value situated between 22° and 23°.
• a variant embodiment according to the invention, presented in FIG. 5, proposes solving this problem by choosing an angular width, a 2 , of the non-coiled teeth (4 to 6) greater than that of the coiled teeth (1 to 3), has . Good results are obtained when the non-coiled teeth (4 to 6) are widened and the coiled teeth (1 to 3) are refined so as to keep a constant total angular spread, that is to say, for example if the coiled teeth are refined by x°, i.e.
• Figures 6a, 6b, 6c represent the torque variations due to the magnetization harmonic 3, perceived by a coiled tooth and an uncoiled tooth as a function of the mechanical angle and represented for an electrical period and for a ratio between the angular widths of the wound teeth a lt and of the unwound teeth a 2 optimized to minimize the torque ripple without current C 0 .
• Figures 6a, 6b, 6c show the case of a 6-tooth stator.
• FIG. 6a presents in curve (101) the simulation of the torque C 06 perceived by the coiled tooth (1) and the curve (102) represents the sum of the torques C 06 perceived by all the teeth (1 to 3) wound.
• These torques have a non-negligible amplitude compared to the torque generated by a coil, curve (100), when it is supplied with the nominal current.
• FIG. 6b presents in curve (103) the torque C 06 simulated for the unwound tooth (4) and the curve (104) presents the sum of the torques C 06 on all of the unwound teeth (4 to 6).
• the couples C 06 simulated for the wound teeth, curve (102), and for the unwound teeth, curve (104) are of the same amplitude but of opposite phase, which leads to a perfect cancellation of the torque C 06 summed over all of the teeth (1 to 6) and represented by the curve (110).
• Figure 7 shows another embodiment with only two uncoiled teeth (4 and 6) and not connected to each other, but connected to the coiled teeth respectively (1 and 3) surrounded by the coils (11, 13).
• the stator surrounds a magnetized rotor (50).
• the term “unconnected teeth” means that there is an interruption in the magnetic continuity between these teeth at the level of the smallest angle separating them, for example by means of a cutout between said teeth of the stack of laminations constituting the stator.
• the space freed up between the unwound teeth (4, 6) makes it possible to house a magneto-sensitive probe (30) to measure the position of the rotor and control the electrical supply to the coils.
• the uncoiled teeth (4, 6) must be widened by a complementary value, i.e.
• FIGS. 8a, 8b, 8c represent the variations in torque due to the 3rd harmonic of magnetization, perceived by a coiled tooth and an uncoiled tooth as a function of the mechanical angle and represented for an electrical period and for a ratio between the angular widths of the wound teeth a lt and of the unwound teeth a 2 optimized to minimize the torque ripple without current C 0 .
• Figures 8a, 8b, 8c show the case of a 5-tooth stator. More particularly, FIG. 8a presents in curve (105) the simulation of the torque C 06 perceived by the coiled tooth (1) and the curve (106) represents the sum of the torques C 06 perceived by all the teeth (1 to 3 ) wound.
• FIG. 8b presents in curve (107) the torque C 06 simulated for the unwound tooth (4) and the curve (108) presents the sum of the torques C 06 on all of the unwound teeth (4, 6).
• the couples C 06 simulated for the wound teeth, curve (106), and for the unwound teeth, curve (108) are of the same amplitude but of opposite phase, which leads to a perfect cancellation of the torque C 06 summed over all of the teeth (1 to 6) and represented by the curve (110).
• a final alternative, not shown, is to compensate for the torque without current using a single non-coiled tooth located in the complementary angular sector.
• Figures 6a, 6b, 6c on the one hand and 8a 8b, 8c on the other hand illustrate the perfect compensation of the torque without current C 06 , achieved using specific tooth widths. Nevertheless, the compensation of the torque without current is not limiting of the invention, because for certain applications a torque amplitude without current non-zero is desired, for example to ensure blocking of the actuator when it is not powered. The person skilled in the art can then adjust the width of the wound teeth to optimize the performance of his machine, then adjust the width of the unwound teeth to obtain the desired value of the torque without current.
• Figure 18 represents a simulation of the magnetic forces in the plane of the laminations (x, y), on each tooth, and for all the rotor positions, when driven by the supply of the coils over an electrical period, each ellipsoid corresponding to one tooth.
• the curves (201, 202, 203) represent the forces on the wound teeth (1, 2, 3) when all the teeth are equal
• the curves (204, 205, 206) represent the forces on the unwound teeth (4, 5, 6) when all the teeth are equal
• the curves (301, 302, 303) represent the forces on the coiled teeth (1, 2, 3) when the uncoiled teeth are angularly wider
• the curves (304, 305, 306) represent the forces on the unwound teeth (4, 5, 6) when the unwound teeth are angularly wider. It can be noticed that when the unwound teeth are wider, the ellipsoids have a lower surface area, which corresponds to lower forces. This is attested by FIG.
• the stator (8) may be formed of two parts assembled, for example by a dovetail, one of the parts (81) comprising the angular sector with the teeth supporting the coils (11, 12, 13), and the other part (82) comprising the complementary angular sector having the uncoiled teeth (4, 5, 6).
• This embodiment makes it possible in particular to thread long coils (11, 12, 13), the length of which is greater than the diameter of the rotor (50).
• the invention is not limited to a rotor of the ring type with 4 pairs of poles, as shown in FIG. 1, but can use any variant of rotor known to those skilled in the art.
• the rotor (501) can have 8 buried magnets (51), but one could also imagine a more economical magnet alternative, such as that shown in this same figure with the rotor (502 ), by alternating magnet poles (53) with salient poles (52) of a soft ferromagnetic material.
• the rotor comprises 4 pairs of magnetized poles, the invention however not being limited to this number, a lower number of poles can also be used, while benefiting from the advantages conferred by the invention, by choosing judiciously the geometric characteristics of the teeth (4 to 6) devoid of coils.
• FIG. 16 presents a possible variant of a rotor provided with 2 pairs of poles.
• the coiled teeth (1, 2, 3) may have a frontal flare, called tooth beak, allowing more space to be allocated for the coils while optimizing the collection rotor flux.
• the non-wound teeth can themselves, in addition or alternatively, have tooth beaks so as to, for example, refine the teeth to lighten the stator as much as possible.
• FIG. 12 illustrates different coupling configurations of the rotor with the first module of a reduction train and Figure 15 shows a possible integration in a geared motor box also comprising control electronics presenting the motor control means three-phase.
• the rotor (50) is integral with a pinion (51) which meshes with the toothed street of a first motion reduction module (52). This first module is supported by a shaft (53) whose arrangement is limited by the size of the magnetic circuit.
• Figure 12 illustrates the possibility of inserting this axle between two unwound teeth (4, 5), which makes it possible to obtain greater latitude for the diameters of the pinion (51) and of the wheel of the module (52) and therefore more choice on the reduction of this first stage.
• Figure 13 illustrates another possible positioning of the axis (53) on the periphery of two coils (12, 13). This configuration makes it possible to completely free up the space situated in the angular sector which does not contain a coil and therefore to position the stator in the corner of the casing of a geared motor so as to obtain a very compact solution.
• FIG. 14 illustrates the possibility of inserting the pin (53) into the free angular sector of a version of the invention with two non-coiled teeth, as shown in FIG. 7.
• the two non-coiled teeth ( 4, 6) are not connected by a ferromagnetic circuit and the free space can be used to accommodate the sprocket (54) of the first module (52) of the reduction chain. This makes it possible to obtain a very compact version in the axial direction.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Iron Core Of Rotating Electric Machines (AREA)
• Permanent Magnet Type Synchronous Machine (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=77519247

Family Applications (1)

Country Status (6)

Family Cites Families (5)

• 2021
  • 2021-06-14 FR FR2106266A patent/FR3124035B1/fr active Active
• 2022
  • 2022-06-14 EP EP22741343.2A patent/EP4356498A1/de active Pending
  • 2022-06-14 WO PCT/FR2022/051146 patent/WO2022263769A1/fr active Application Filing
  • 2022-06-14 JP JP2023577189A patent/JP2024521477A/ja active Pending
  • 2022-06-14 CN CN202280053310.2A patent/CN117730472A/zh active Pending
  • 2022-06-14 KR KR1020247001050A patent/KR20240021254A/ko unknown

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