(19)
(11)EP 2 078 333 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
01.07.2020 Bulletin 2020/27

(21)Application number: 07863862.4

(22)Date of filing:  02.11.2007
(51)International Patent Classification (IPC): 
H02K 33/16(2006.01)
A46B 13/00(2006.01)
A46B 13/02(2006.01)
(86)International application number:
PCT/US2007/083524
(87)International publication number:
WO 2008/058030 (15.05.2008 Gazette  2008/20)

(54)

OSCILLATING MOTOR FOR A PERSONAL CARE APPLIANCE

SCHWINGANKERMOTOR FÜR EIN KÖRPERPFLEGEGERÄT

MOTEUR OSCILLANT POUR UN APPAREIL DE SOINS PERSONNELS


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR

(30)Priority: 03.11.2006 US 556282

(43)Date of publication of application:
15.07.2009 Bulletin 2009/29

(73)Proprietor: L'Oréal SA
75008 Paris (FR)

(72)Inventors:
  • REISHUS, Richard A.
    Renton, WA 98058 (US)
  • MEGINNISS III, Stephen M.
    Seattle, WA 98119 (US)
  • PILCHER, Kenneth A.
    Seattle, WA 98107 (US)

(74)Representative: Faulkner, Thomas John et al
Cleveland 10 Fetter Lane
London EC4A 1BR
London EC4A 1BR (GB)


(56)References cited: : 
WO-A1-2006/002182
US-A- 3 173 119
US-A1- 2005 280 319
US-B1- 6 275 624
US-B2- 6 760 945
FR-A1- 2 268 386
US-A1- 2003 204 924
US-B1- 6 275 624
US-B1- 6 581 974
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Technical Field



    [0001] This invention relates generally to motors for a personal care appliance, such as a power skin brush, and more specifically concerns an electromagnetic motor using flexure elements to produce an oscillating action of the workpiece portion of the personal care appliance.

    Background of the Invention



    [0002] Personal care appliances typically use an internal motor to produce a particular workpiece movement/action, which in turn produces desired functional results. Examples of such appliances include power skin brushes, power toothbrushes and shavers, among others.

    [0003] Many such devices have a motor arrangement which produces an oscillating (back and forth) action rather than a purely rotational movement. Such arrangements require not only the typical motor bearing structures for support of the motion, but also specific structural elements to constrain the movement of the motor drive shaft and the workpiece to a selected angle/movement. Such bearings or other elements typically add significant expense and manufacturing difficulties to the manufacture of the appliance as well as reliability/durability concerns to the use of the appliance.

    [0004] Hence, it is desirable to have a motor for a personal care appliance which produces a desired oscillating action, and which is also rugged, quiet, and does not require bearings or constraining members for operation.

    [0005] WO 2006/002182 A1 describes a motor assembly which produces an oscillating action for a personal care device.

    [0006] US 2003/204924 A1 describes an apparatus for converting side-to-side motion to rotational motion for a workpiece.

    [0007] US 6275624 B1 describes an optical switch for use in optical telecommunication applications.

    [0008] FR 2268386 A1 describes a motor for an electric razor.

    Summary of the Invention



    [0009] The invention provides a motor for a personal care appliance, comprising: a stator assembly portion driven by a drive assembly which includes a source of alternating current; an armature portion responsive to the stator action to move through a path; a mounting member affixed to a housing portion of the personal care appliance; a flexure assembly connected between the armature and the mounting member, such that the armature in operation moves in an arcuate path about a pivot point located between the mounting member and the armature; and a workpiece assembly mounted to and extending from the armature such that the workpiece oscillates through an angle; wherein the flexure assembly includes at least two separate flexure members which cross each other between the mounting member and the armature, wherein the armature moves about a pivot point approximately where the flexure members cross.

    Brief Description of the Drawings



    [0010] 

    Figure 1 is a partial perspective view of a personal care skin brush appliance incorporating the appliance motor which embodies the present invention.

    Figure 2 as a perspective view of the appliance motor of Figure 1.

    Figure 3 is a top view of the motor of Figures 1 and 2.

    Figure 4 is a top view of the motor of Figures 1 and 2 with selected portions thereof removed.

    Figure 5 is a top view of the motor of Figures 1 and 2 showing only the magnets and backiron portions thereof.


    Best Mode for Carrying Out the Invention



    [0011] Figure 1 shows a personal care appliance in the form of a power skin brush. The personal care appliance 10 includes a case or housing 12 through which an on/off switch 14 extends to contact a button on the case or the like for control of the appliance.

    [0012] Positioned within case 12 is a motor 16 and a drive assembly, which includes an electronic drive circuit 20 and rechargeable batteries 22 which provide a self-contained source of power for the appliance. The appliance 10 in the embodiment shown also includes a charging coil 24 which operates with a conventional charger (not shown) to maintain batteries 22 in a charged condition.

    [0013] The appliance further includes a workpiece mounting arm 28 which extends from an armature portion of the motor 16. Mounted on the free end of arm 28 is a specific workpiece 30, which in the embodiment shown is a skin brush. Such a skin brush is shown and described in more detail in co-pending application Serial No. 10/873,352. However, the workpiece 30 can take various forms, including, for example, a toothbrush brushhead or a shaving head. In operation, the workpiece will oscillate back and forth through a desired angle due to the action of the motor 16. Typically, but not necessarily, the oscillation will be rotational. The movement may also include a translational component as well, as discussed below.

    [0014] Figures 2 and 3 show the motor 16 in more detail. The motor includes a stator portion 36, which in the embodiment shown is an E-core with a center leg 37 upon which a stator coil 38 is mounted and two outer legs 40 and 42. An armature portion 46 of the motor 16 has a curved configuration with tip ends 49 and 50 which come closely adjacent the curved tip ends of outer legs 40 and 42 of the stator E-core. The armature portion 46 includes a backiron member 48 which is made from a ferromagnetic material. Two or more spaced magnets 51 and 52 are mounted on the backiron, with magnetization in the radial direction, arranged such that the north pole of one magnet 51 faces outward, while the south pole of the other magnet 52 faces outward, although it should be understood that the orientation could be reversed as long as the magnet poles point in opposite directions. The motor 16 also includes a mounting element 54 which is secured to the case 12 of the appliance, thus becoming a mechanical reference for the oscillating system.

    [0015] Connecting the armature 46 to the mounting element 54 are a pair of flexure elements, in this embodiment flexure elements 58 and 60, although additional flexure elements can be used. In one example, the flexure elements are made from spring steel material, and are approximately 0.064cm (0.025 inch) thick. Each flexure element is approximately 1.3cm (0.50 inch) high. Flexure elements 58 and 60 are oriented approximately perpendicular to each other. The point of overlap between the flexure elements 58 and 60 is the functional pivot point 66 about which armature 46 oscillates.

    [0016] Extending from the armature 46 is the mounting arm 28. As can be seen most clearly in Figure 2, mounting arm 28 extends outwardly from the armature and then extends horizontally (parallel with the handle of the appliance) until it reaches a line extending through pivot point 66, where the mounting arm extends outwardly again approximately at a right angle to the handle. Mounted on the free end of mounting arm 28 is workpiece 30, which, for example, is a skin brush, as indicated above. The configuration of the mounting arm is thus such that: the brush oscillates about an axis which extends through pivot point 66 at a right angle to the handle. The location/orientation of the output shaft can be changed, for instance by moving the location of the tip away from axis at the pivot point 66, to produce a combined rotational/translational movement of the workpiece.

    [0017] Referring to Figure 4, the E-core 36, backiron 48, magnets 52, 52 and flexure elements 58, 60 are shown alone for clarity. The geometry of the E-core in relation to the width of the face of magnets 51, 52 is important for maximum efficiency of the motor. Specifically, the width of the E-core center leg 37 should be from 0.50 to 0.60 (preferably 0.56) times the width of the face of the magnets. The width of the outer legs 40, 42 should be from 0.90 to 1.10 (preferably 1.02) times the width of the face of the magnets. The width of the distances 70, 72 between center leg 37 and outer legs 40, 42, respectively, should be from 1.95 to 2.20 (preferably 2.07) times the width of the face of the magnets. The length of center leg 37 should be from 1.95 to 2.15 (preferably 2.06) time the width of distances 70, 72.

    [0018] Further, the distance between the centers of the faces of magnets 51, 52 should be from 2.40 to 2.60 (preferably 2.49) times the width of the face of the magnets. It is also advantageous to motor efficiency to set magnets 51,52 at an angle with respect to each other such that a line normal to the face of the magnets, passing through the midpoint of the magnet face also passes through the pivot axis of the armature. In the embodiment shown, the angle 74 between the midpoint line 76 and the line 78 normal to the magnet face (both passing through pivot axis) is from 18° to 22° (preferably 20°). It should be noted that this angle can vary depending on the radius at which the magnets rotate about the pivot axis. As the radius increases, the angle decreases.

    [0019] In operation, an alternating current is generated by the electronic current assembly and applied to the stator coil 36, resulting in an arcuate movement of the armature about the pivot point 66, due to the attractive/repulsive action between the three legs 37, 40, 42 of the stator E-coil and permanent magnets 51, 52 on the backiron 48. The particular arrangement of the stator E-coil and the armature results in a substantially rotational oscillation of a selected angle about the pivot axis 66. The instantaneous center of rotation moves in a very small 0.025cm (approximately 0.010 inches) complex curve offset about the shaft center point when it is at rest. The angular range of oscillation can be varied, depending upon the configuration of the armature and the stator and the characteristics of the alternating drive current. Preferably, the motion is within the range of ±3° to ±15° about the pivot axis.

    [0020] The flexure elements, with their configuration and aspect ratio, connected between the armature and the mounting member, constrain the movement of the armature to substantially rotational action about a line generally passing through the pivot axis, eliminating the need for bearings and other elements to constrain the oscillating movement of the workpiece.

    [0021] The arrangement shown and described above is for a device where the axis of rotation of the motor shaft, and hence the brush, is at a right angle to the longitudinal axis of the handle portion of the device. In another arrangement, the magnets on the backiron portion of the armature may be affixed to the side of the armature away from the workpiece, with a magnetization arrangement/orientation parallel to the axis of rotation and with the stator assembly arranged in line with the axis of rotation, rather than the radial magnetization, right angle axis of rotation arrangement discussed above. This axial arrangement is suitable for a device having a desired axis of rotation of the motor drive shaft substantially parallel to the longitudinal axis of the handle portion of the device.

    [0022] Hence, a new motor arrangement for a personal care appliance has been disclosed which produces an oscillation over a defined angle without the need for bearings or other special constraining elements.

    [0023] Although a preferred embodiment of the invention has been disclosed for purposes of illustration, it should be understood that various changes, modifications and substitutions may be incorporated in the embodiment, without departing form the appended claims.


    Claims

    1. A motor (16) for a personal care appliance (10), comprising:

    a stator assembly portion (36) driven by a drive assembly which includes a source of alternating current;

    an armature portion (46) responsive to the stator action to move through a path;

    a mounting member (54) affixed to a housing portion (12) of the personal care appliance (10);

    a flexure assembly (58;60) connected between the armature (46) and the mounting member (54), such that the armature (46) in operation moves in an arcuate path about a pivot point (66) located between the mounting member (54) and the armature (46); and

    a workpiece assembly (30) mounted to and extending from the armature (46) such that the workpiece (30) oscillates through an angle;

    wherein the flexure assembly (58:60) includes at least two separate flexure members (58; 60) which are orientated approximately perpendicular to each other so as to cross each other between the mounting member (54) and the armature (46), wherein the armature (46) moves about a pivot point (66) approximately where the two flexure members (58; 60) cross.


     
    2. The motor (16) of claim 1, wherein the angle is approximately within the range of ±3 ° to ±15 °.
     
    3. The motor (16) of claim 1, wherein the workpiece (30) is a skin brush.
     
    4. The motor (16) of claim 1, wherein the mounting assembly (54) includes a mounting arm (28) which is mounted to and extends from the armature (46), and wherein the workpiece (30) is mounted upon a free end of the mounting arm (28).
     
    5. The motor (16) of claim 1, wherein the motor is a motor of a personal care appliance, and wherein the mounting arm (28) and the armature (46) are arranged so that the workpiece (30) rotates about an axis approximately at right angles to a longitudinal axis of the handle portion of the personal care appliance.
     
    6. The motor (16) of claim 1, wherein the motor is a motor of a personal care appliance, and wherein the mounting arm (28) and the armature (46) are arranged so that the workpiece (30) rotates about an axis which is approximately parallel to a longitudinal axis of the handle portion of the personal care appliance.
     
    7. The motor (16) of claim 1, wherein the stator portion (36) includes an E-core member having a center leg (37) and two outer legs (40;42), wherein the armature portion (46) includes a backiron (48) which has two spaced magnets (51;52) mounted thereon with the magnetic poles thereof aligned in opposing directions, and wherein the width of the center leg (37) of the E-core member is approximately 0.50-0.60 times the width of the faces of the magnets (51;52), the width of the outer legs (40;42) is approximately 0.90-1.10 times the width of the faces of the magnets (51;52), the width of the distance between the center leg (37) and the two outer legs (40;42), respectively, is 1.95-2.20 times the width of the magnet face (51;52) and the length of the center leg (37) is 1.95-2.15 times the width of said distance between the center leg (37) and the two outer legs (40;42).
     
    8. The motor (16) of claim 7, wherein the distance between the centers of the magnets (51;52) is 2.40-2.60 times the width of the faces of the magnets (51;52) and wherein the magnets (51;52) are positioned at an angle in the range of 18-22 ° relative to a line passing through a midpoint of the backiron (48) and said pivot point (66).
     
    9. The motor (16) of claim 7, wherein the angle of oscillation of the workpiece (30) is approximately within the range of ±3 ° to ±15°.
     


    Ansprüche

    1. Motor (16) für ein Körperpflegegerät (10), Folgendes umfassend:

    einen Statoranordnungsabschnitt (36), der durch eine Antriebsanordnung angetrieben wird, die eine Wechselstromquelle beinhaltet,

    einen Läuferabschnitt (46), der auf die Statoraktion reaktionsfähig ist, um sich über einen Weg zu bewegen,

    ein Montageelement (54), das an einem Gehäuseabschnitt (12) des Körperpflegegeräts (10) befestigt ist,

    eine Biegeanordnung (58; 60), die derart zwischen dem Läufer (46) und dem Montageelement (54) eingebunden ist, dass sich der Läufer (46) während des Betriebes in einem Bogenweg um einen Schwenkpunkt (66) bewegt, der sich zwischen dem Montageelement (54) und dem Läufer (46) befindet, und

    eine Werkstückanordnung (30), die derart an den Läufer (46) montiert ist und sich von diesem aus erstreckt, dass das Werkstück (30) über einen Winkel schwingt,

    wobei die Biegeanordnung (58; 60) mindestens zwei separate Biegeelemente (58; 60) beinhaltet, die ungefähr senkrecht zueinander ausgerichtet sind, so dass sie einander zwischen dem Montageelement (54) und

    dem Läufer (46) kreuzen, wobei sich der Läufer (46) ungefähr dort, wo sich die zwei Biegeelemente (58; 60) kreuzen, um einen Schwenkpunkt (66) bewegt.


     
    2. Motor (16) nach Anspruch 1, wobei der Winkel ungefähr im Bereich von ±3° bis ±15° liegt.
     
    3. Motor (16) nach Anspruch 1, wobei das Werkstück (30) eine Hautbürste ist.
     
    4. Motor (16) nach Anspruch 1, wobei die Montageanordnung (54) einen Montagearm (28) beinhaltet, der an den Läufer (46) montiert ist und sich von diesem aus erstreckt, und wobei das Werkstück (30) an ein freies Ende des Montagearms (28) montiert ist.
     
    5. Motor (16) nach Anspruch 1, wobei der Motor ein Motor eines Körperpflegegeräts ist und wobei der Montagearm (28) und der Läufer (46) derart angeordnet sind, dass sich das Werkstück (30) um eine Achse dreht, die in ungefähr rechten Winkeln zu einer Längsachse des Griffabschnitts des Körperpflegegeräts liegt.
     
    6. Motor (16) nach Anspruch 1, wobei der Motor ein Motor eines Körperpflegegeräts ist und wobei der Montagearm (28) und der Läufer (46) derart angeordnet sind, dass sich das Werkstück (30) um eine Achse dreht, die ungefähr parallel zu einer Längsachse des Griffabschnitts des Körperpflegegeräts liegt.
     
    7. Motor (16) nach Anspruch 1, wobei der Statorabschnitt (36) ein E-förmiges Kernelement mit einem mittleren Schenkel (37) und zwei äußeren Schenkeln (40; 42) beinhaltet, wobei der Läuferabschnitt (46) einen magnetischen Rückschluss (48) beinhaltet, an dem zwei beabstandete Magnete (51; 52) montiert sind, deren Magnetpole in entgegengesetzte Richtungen gerichtet sind, und wobei die Breite des mittleren Schenkels (37) des E-förmigen Kernelements ungefähr das 0,50- bis 0,60-Fache der Breite der Flächen der Magnete (51; 52) beträgt, die Breite der äußeren Schenkel (40; 42) ungefähr das 0,90- bis 1,10-Fache der Breite der Flächen der Magnete (51; 52) beträgt, die Breite des Abstandes zwischen dem mittleren Schenkel (37) und den zwei äußeren Schenkeln (40; 42) jeweils das 1,95- bis 2,20-Fache der Breite der Magnetflächen (51; 52) beträgt und die Länge des mittleren Schenkels das 1,95-bis 2,15-Fache der Breite des Abstandes zwischen dem mittleren Schenkel (37) und den zwei äußeren Schenkeln (40; 42) beträgt.
     
    8. Motor (16) nach Anspruch 7, wobei der Abstand zwischen den Mitten der Magnete (51; 52) das 2,40- bis 2,60-Fache der Breite der Flächen der Magnete (51; 52) beträgt und wobei die Magnete (51; 52) im Verhältnis zu einer Linie, die durch einen Mittelpunkt des magnetischen Rückschlusses (48) und den Schwenkpunkt (66) verläuft, in einem Winkel im Bereich von 18 bis 22° positioniert sind.
     
    9. Motor (16) nach Anspruch 7, wobei der Winkel der Schwingung des Werkstücks (30) ungefähr im Bereich von ±3° bis ±15° liegt.
     


    Revendications

    1. Moteur (16) pour un appareil de soins personnels (10), comportant :

    une partie formant ensemble stator (36) entraînée par un ensemble d'entraînement qui comprend une source de courant alternatif ;

    une partie formant induit (46) qui réagit à l'action du stator à des fins de déplacement au travers d'une trajectoire ;

    un élément de montage (54) fixé sur une partie formant boîtier (12) de l'appareil de soins personnels (10) ;

    un ensemble de flexion (58 ; 60) raccordé entre l'induit (46) et l'élément de montage (54), de telle sorte que l'induit (46) en cours de fonctionnement se déplace dans une trajectoire arquée autour d'un point de pivotement (66) situé entre l'élément de montage (54) et l'induit (46) ; et

    un ensemble formant pièce de travail (30) monté sur l'induit (46) et s'étendant en provenance de celui-ci de telle sorte que la pièce de travail (30) oscille selon un angle ;

    dans lequel l'ensemble de flexion (58 ; 60) comprend au moins deux éléments de flexion séparés (58 ; 60) qui sont orientés de manière approximativement perpendiculaire l'un par rapport à l'autre de manière à se croiser l'un l'autre entre l'élément de montage (54) et l'induit (46), dans lequel l'induit (46) se déplace autour d'un point de pivotement (66) approximativement là où les deux éléments de flexion (58 ; 60) se croisent.


     
    2. Moteur (16) selon la revendication 1, dans lequel l'angle se trouve approximativement dans la plage allant de ± 3° à ± 15°.
     
    3. Moteur (16) selon la revendication 1, dans lequel la pièce de travail (30) est une brosse pour la peau.
     
    4. Moteur (16) selon la revendication 1, dans lequel l'ensemble de montage (54) comprend un bras de montage (28) qui est monté sur l'induit (46) et qui s'étend en provenance de celui-ci, et dans lequel la pièce de travail (30) est montée sur une extrémité libre du bras de montage (28).
     
    5. Moteur (16) selon la revendication 1, dans lequel le moteur est un moteur d'un appareil de soins personnels, et dans lequel le bras de montage (28) et l'induit (46) sont agencés de telle sorte que la pièce de travail (30) tourne autour d'un axe approximativement selon des angles droits par rapport à un axe longitudinal de la partie formant manche de l'appareil de soins personnels.
     
    6. Moteur (16) selon la revendication 1, dans lequel le moteur est un moteur d'un appareil de soins personnels, et dans lequel le bras de montage (28) et l'induit (46) sont agencés de telle sorte que la pièce de travail (30) tourne autour d'un axe qui est approximativement parallèle par rapport à un axe longitudinal de la partie formant manche de l'appareil de soins personnels.
     
    7. Moteur (16) selon la revendication 1, dans lequel la partie formant stator (36) comprend un élément de noyau en forme de E ayant une branche centrale (37) et deux branches extérieures (40 ; 42), dans lequel la partie formant induit (46) comprend un contre-fer (48) qui a deux aimants espacés (51 ; 52) montés sur celui-ci dont les pôles magnétiques sont alignés dans des directions opposées, et dans lequel la largeur de la branche centrale (37) de l'élément de noyau en forme de E est approximativement de 0,50 à 0,60 fois la largeur des faces des aimants (51 ; 52), la largeur des branches extérieures (40 ; 42) est approximativement de 0,90 à 1,10 fois la largeur des faces des aimants (51 ; 52), la largeur de la distance entre la branche centrale (37) et les deux branches extérieures (40 ; 42), respectivement, est de 1,95 à 2,20 fois la largeur de la face des aimants (51 ; 52) et la longueur de la branche centrale (37) est de 1,95 à 2,15 fois la largeur de ladite distance entre la branche centrale (37) et les deux branches extérieures (40 ; 42).
     
    8. Moteur (16) selon la revendication 7, dans lequel la distance entre les centres des aimants (51 ; 52) est de 2,40 à 2,60 fois la largeur des faces des aimants (51 ; 52) et dans lequel les aimants (51 ; 52) sont positionnés selon un angle se trouvant dans la plage allant de 18° à 22° par rapport à une ligne traversant un point médian du contre-fer (48) et dudit point de pivotement (66).
     
    9. Moteur (16) selon la revendication 7, dans lequel l'angle d'oscillation de la pièce de travail (30) se trouve approximativement dans la plage allant de ± 3° à ± 15°.
     




    Drawing














    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description