Classifications

• • 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
  • H02K21/18—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures having horse-shoe armature cores
• • 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
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
  • H02K15/02—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
• • 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

Definitions

• the present invention relates to a motor of small dimensions provided in particular for driving the hands of an analog display device. More particularly, the invention relates to a two-phase type motor having a rotor provided with a bipolar permanent magnet arranged in an opening of the stator and having a radial magnetic polarization relative to the axis of rotation of the rotor.
• the motor according to the invention can be used in a device for driving needles indicating the value of a measured physical quantity, in particular time in the watchmaking field, speed or frequency.
• the engine of the present invention can advantageously be used for driving the needle of a counter arranged in a dashboard of a car.
• a person skilled in the art knows several two-phase motors of small dimensions used for the analog display drive.
• Such a motor whose stator has three magnetic poles distributed respectively in three circular sectors of 120 ° around the stator opening. One of the three poles is common to the two main magnetic circuits of this motor.
• Such a motor can be of relatively inexpensive construction and have a flat stator structure which is advantageous for integration into thin devices, in particular in a watch movement.
• such a motor has the disadvantage of not being magnetically symmetrical, that is to say with fluxes coupled between the magnet of the rotor and each of the two coils which are in phase quadrature (phase shift of approximately 90 °).
• such a two-phase motor has at the level of the magnetic poles of the stator a structure specific to a three-phase motor with a phase shift of approximately 120 ° between the coupled magnet-coil fluxes.
• the non-symmetry of the coupled flows generates a high drawing torque, which limits the useful torque of the motor in dynamic regime, increases the electric consumption, and generates vibrations of the motor.
• the trade also knows symmetrical two-phase motors having four magnetic poles coupled in pairs to a coil.
• the two magnetic circuits of the motor are provided independent of each other, that is to say magnetically isolated. The machining and assembly of such motors is generally more expensive than for the two-phase motor with three magnetic poles previously described.
• the magnetic insulation of the two magnetic circuits of the stator which cross each other generally requires a construction with a stator having a greater thickness or height; this in particular to allow the arrangement of an air gap in the superposition region of the two magnetic circuits.
• the object of the present invention is to provide a two-phase motor of the symmetrical type and having a flat stator structure, a small footprint and a high efficiency, with a reduced manufacturing cost.
• the present invention relates to a two-phase motor of small dimensions formed by a stator carrying two power coils and a rotor provided with a bipolar permanent magnet, the stator defining first, second and third magnetic poles. main which together define a stator opening in which is housed the bipolar rotor magnet.
• the first and second main poles are respectively connected to the third main pole by two magnetic cores each carrying one of the two coils.
• This motor is characterized in that the third main magnetic pole defines two adjacent secondary poles, separated by a zone with high magnetic reluctance in the peripheral region at the stator opening.
• the first and second main poles and said two secondary poles are distributed in four circular sectors of approximately 90 ° around the stator opening.
• the zone with high magnetic reluctance separating the two secondary poles is defined by a non-traversing slot and opening into this stator opening. This relatively long slit thus enters the third main pole without dividing the latter into two.
• the slot is therefore blind.
• the stator is constituted by an iron-silicon alloy.
• FIG. 1 is a perspective view of the stator and the permanent magnet of the rotor of a first variant of an embodiment of the motor according to the invention
• - Figure 2 is a top view of the engine of Figure 1
• - Figure 3 graphically shows the coupled magnet-coil flux for each of the two coils of the first embodiment as a function of the angular position of the rotor
• - Figure 4 is a top view of a second alternative embodiment of the motor according to the invention
• - Figure 5 shows the stator of a second embodiment of the motor according to the invention
• - Figures 6a to 6d describe steps of the manufacturing method according to the present invention of an engine according to the second embodiment.
• the motor according to the first alternative embodiment comprises a stator 2 and a rotor 4 provided with a bipolar permanent magnet 6 of annular shape and of radial magnetization.
• the stator 2 is formed by three main magnetic poles 8, 10 and 12.
• the first and second main poles 8 and 10 are respectively connected to the third main pole 12 by two magnetic cores 16 and 18 having the general shape of an L.
• the three main magnetic poles define a stator opening 40 in which is housed the permanent magnet 6.
• the cores 16 and 18 respectively carry two power coils 20 and 22.
• the third main pole defines two secondary magnetic poles 26 and 28, these two secondary poles being adjacent and partially defining the stator opening 40.
• the two secondary poles 26 and 28 are separated by a high reluctance zone 30 defining an air gap between the two secondary poles in the peripheral region of the stator opening.
• the air gap 30 is formed by a blind slot opening into the opening 40.
• the slot 30 is therefore non-traversing and dimensioned so that the two secondary magnetic poles 26 and 28 are magnetically connected by the external part 36 of the pole 12.
• This external part is characterized by a high magnetic permeability.
• the first and second main poles 8 and 10 and the two secondary poles 26 and 28 are distributed in four circular sectors of approximately 90 ° around the stator opening, that is to say relatively to the geometrical axis of rotation of the rotor 4.
• each of these four poles has a polar expansion offset angularly by approximately 90 ° relative to the adjacent poles.
• the secondary poles 26 and 28 are separated from the two main poles 8 and 10 respectively by two air gaps 31 and 32 defining two through slots.
• the two main poles 8 and 10 are separated by an air gap 33 defining a third through slot. It will be noted that the slots 31, 32 and 33 have in their external part notches used for assembly and the positioning of the stator parts.
• the slot 30 is terminated by a circular hole 35 provided for the passage of a stator positioning pin arranged in a housing intended to receive the motor according to the invention.
• FIG. 3 is shown the magnet-coil coupled flux for each of the two coils 20 and 22.
• the two curves 46 and 48 obtained by simulation respectively for the two coils 20 and 22 have a phase shift of approximately 90 °.
• the structure of the stator poles and the use of a bipolar magnet with radial magnetization give the motor of the invention an almost symmetrical behavior.
• the stator is preferably made of Fe-Si in the embodiment described.
• FIG. 4 schematically represents a second variant embodiment of the invention.
• This second variant is distinguished in particular by the fact that the various stator parts have simple shapes, easy to machine or to form.
• the main poles 8A and 10A of the stator 2 have a generally rectangular shape, with a recess in an angle, having a concave circular profile, to define the opening in which the rotor is arranged.
• the rotor is mounted in a cage 52 having a hole for the passage of its shaft, this shaft carrying outside the cage a gear pinion 54.
• the third main pole 12A differs from the first variant by the fact that the slot 30 has a constant width corresponding to the diameter of a pad 56 for positioning this third pole 12A.
• the motor is arranged on a support 50 having four positioning pads 56, 57, 58 and 59. These pads have a base 62 having a first diameter and an upper part 64 having a second diameter less than the first diameter.
• the base 62 is used for positioning the stator parts, while the upper part 64 is used for centering the cage 52 of the rotor.
• the cores 16A and 18A have a rectangular shape.
• stator parts can be assembled to the other stator parts by screws or other known fastening elements, by laser welding, by bonding with a material with good magnetic permeability or simply be held in place by parts of a housing designed to receive the engine of the invention.
• a housing designed to receive the engine of the invention.
• the motor housing can include other studs or other means for positioning the various parts of this motor.
• the coils 20 and 22 are wound on respective supports 66 and 68. These supports can in particular be used for the arrangement of electrical contacts for supplying the coils.
• Figure 5 is shown the stator 2 of a second embodiment of an engine according to the invention.
• This motor is composed of three parts defining three main magnetic poles 8, 10 and 12.
• the pole 12 defines two secondary poles 26 and 28 separated by a slot 77 ending in a circular recess.
• the poles 8, 10 and 12 are magnetically separated from each other by slots 74a, 75a and 76a.
• the opening 40 provided for the permanent magnet of the rotor has a diameter D.
• the slot 77 separating the two secondary poles 26 and 28 is blind and has a depth P. This depth P is slightly less than the diameter D. It will thus be noted that the slot 77 has a relatively large depth P, this dimension here being of the same order of magnitude as that of the diameter D of the opening 40.
• the two coil cores have not been shown in FIG. 5, but their arrangement is similar to that of FIG. 4.
• the stator 2 is machined so that the magnetic circuits have minimum widths X, Y and Z substantially equal.
• FIGS. 6a to 6d the steps of a method of manufacturing according to the present invention will be described below for a stator with several magnetic poles provided in a single general plan.
• the stator of a motor according to the method of the invention is produced from a plate 72 of magnetic material which is, in a first step, cut so as to define the opening 40 for the passage of the rotor and several poles magnetic 8, 10, 26 and 28 defining this opening 40.
• the magnetic poles are at this stage interconnected and separated by blind slots 74, 75, 76 and 77. Thus, the magnetic poles remain at this stage formed physically by a single flat piece.
• the blind slots are arranged at the periphery of the opening 40 and more precisely define the blooming of the magnetic poles provided. It will be noted here that one of the blind slots 74, 75 or 76 may, in a variant, pass through already at this stage. However, the shape of the part 72 shown in Figure 6a is preferred. As the part 72 is unitary, the opening 40 can be machined very precisely. The magnetic poles 8, 10, 26 and 28 are located in the same general plane of the stator. In a second step, an annular element 80 is brought to the cut plate 72 and this is centered relative to the opening 40, as shown in FIG. 6b.
• the blind slots 74, 75 and 76 and the annular element 80 are arranged so that this element passes over the slots 74, 75, 76 and 77, the latter extending beyond the external contour or around the element. annular 80.
• this element 80 at least partially covers the magnetic poles 8, 10, 26 and 28.
• the element 10 is made of a non-magnetic material and in a variant it is envisaged to use a material weakly magnetic relative to the stator, so as to limit the leakage of magnetic flux.
• the annular element is formed from a metal which is little or not magnetic.
• this element 10 is made of stainless steel. Then, the annular element 80 is fixed to the magnetic poles, as shown in Figure 6b.
• the annular element 80 is fixed by laser welding. This makes it possible to precisely control the quantity of energy supplied and to avoid overheating the part 72, which could otherwise lead to a structural modification of the plate 72 and therefore of the magnetic properties in the regions of the polar expansions.
• the welding can be carried out through the element 80 in regions 82 to 85.
• the laser beam used is projected on the upper face of the annular element relative to the stator defined at this stage again by the plate 72.
• the plate 72 is cut so as to extend the slots 74, 75 and 76 to then obtain through slots 74a, 75a and 76a.
• the main magnetic poles 8, 10 and 12 are separated magnetically. More generally, the method is applied as soon as it is desired to separate at least one of the magnetic poles from the other poles of the stator.
• the stator 2 thus obtained corresponds to the second embodiment of a motor according to the invention shown in FIG. 5.
• the last cutting step has no consequence on the positioning of the magnetic poles, these being held rigidly in place by the ring or ring 80.
• this ring stiffens the stator in the region of the opening 40 provided for the permanent magnet of the rotor.
• Other means of fixing the ring 80 to the part 72 can be provided, in particular electric welding or an adhesive. However, laser welding is the preferred variant, in particular for the reason mentioned above.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Iron Core Of Rotating Electric Machines (AREA)
• Manufacture Of Motors, Generators (AREA)
• Permanent Magnet Type Synchronous Machine (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Publications (1)

Family

ID=34746024

Family Applications (2)

Family Applications Before (1)

Country Status (6)

Families Citing this family (8)

Family Cites Families (15)

• 2004
  • 2004-03-05 EP EP04005345A patent/EP1571749A1/de not_active Withdrawn
• 2005
  • 2005-03-07 WO PCT/EP2005/002385 patent/WO2005096477A1/fr active Application Filing
  • 2005-03-07 CN CNA2005800069307A patent/CN1947327A/zh active Pending
  • 2005-03-07 EP EP05715796A patent/EP1726080A1/de not_active Withdrawn
  • 2005-03-07 JP JP2007501241A patent/JP2007526736A/ja active Pending
  • 2005-03-07 US US10/598,548 patent/US20070164617A1/en not_active Abandoned
  • 2005-03-07 KR KR1020067018943A patent/KR20070002015A/ko not_active Application Discontinuation

Non-Patent Citations (1)

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