• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a watch movement comprising a rotating element, an escape wheel (42) or an anchor, which partly forms a magnetic escapement having a magnetic system supported in part by this rotating element, which is provided with at least a functional permanent magnet (20, 22), the set of functional permanent magnets of the rotating element which participate in the magnetic system having a non-zero overall magnetic moment. The rotating element further comprises a permanent magnet for compensating (44) for said overall magnetic moment which is arranged so that the compensating magnetic moment which it generates is oriented parallel to said overall magnetic moment and has a direction opposite to that of the moment. global magnetic. In addition, preferably, provision is made for the compensating magnetic moment to have an intensity substantially equal to that of the overall magnetic moment so as to substantially cancel a parasitic force torque on the rotating element of the magnetic escapement when the latter is crossed by such a uniform external magnetic field.
    公开号:CH716354A2
    申请号:CH00363/20
    申请日:2020-03-26
    公开日:2020-12-30
    发明作者:Di Domenico Gianni
    申请人:Swatch Group Res & Dev Ltd；
    IPC主号:
    专利说明:

    Technical area
    The invention relates to watch movements provided with at least one rotating element participating in at least one magnetic system of the watch movement, this rotating element being provided with at least one functional permanent magnet forming said at least one magnetic system.
    By "rotating element" is understood an element arranged in the watch movement so as to be able to undergo a certain rotation, in a given direction or in both directions. Thus, this expression applies for example as much to an escape wheel as to a balance, an anchor or a lever.
    In particular, the invention relates to a timepiece, in particular a wristwatch, comprising at least one watch movement of the type described above.
    Technological background
    [0004] Various watch movements comprising at least one magnetic system involved in the operation of the watch movement are known from the prior art. In particular, watch movements are known equipped with a magnetic escapement formed by a magnetic system in which at least one magnet carried by an anchor and at least one magnet carried by an escape wheel participate. Such magnetic escapements are described in particular in documents EP_2887157, EP_2911015, EP_3128379, EP_3217227 and CH_712154. There are also known watch movements having a magnetic escapement without a stopper, part of the magnetic system of which is carried by the mechanical resonator of the watch movement and the other part is carried by an escape wheel. Such watch movements are described in particular in documents CH_709031 and CH_713070.
    Document BE 635 519 describes an electric clock with an electromagnetic oscillator, that is to say an oscillator carrying a magnet mounted in the middle of a torsion wire and maintained by an electric coil. So that an external magnetic field does not disturb the operation of the electromagnetic resonator, it is proposed to add a second magnet, with radial magnetization and of polarity opposite to that of the magnet of the resonator, on the torsion wire. Thus, an external magnetic field will not generate a torque of parasitic force acting on the torsion wire,
    Summary of the invention
    The set of functional permanent magnets of a rotating element, which forms a magnetic escapement of a watch movement, often has an overall magnetic moment, the component of which along the axis of rotation of the rotating element is not zero. This poses a technical problem in an environment where there is an external magnetic field. Indeed, in this case, the presence of an external magnetic, insofar as it is not parallel to the axis of rotation of the rotating element, has the effect of generating a moment of force on this element. rotating whose vector has a component perpendicular to the axis of rotation. This perpendicular component of the moment of force tends to rotate the shaft of the rotating member about an axis perpendicular to the axis of rotation, which presses the two pivots of the rotating member against the side surface of the hole. each of the two respective levels. This therefore results in friction which consumes energy and which increases with the intensity of the external magnetic field. If this intensity becomes significant, it is even possible that the parasitic force torque generated by the external magnetic field on the rotating element could stop it. After having demonstrated the aforementioned technical problem, the inventors propose a technical solution making it possible to solve it.
    [0007] Thus, the invention relates to a watch movement comprising a magnetic escapement formed by an escape wheel and an anchor, at least one of which participates in a magnetic system of this magnetic escapement and is provided with at least one functional permanent magnet forming the magnetic system, all of the functional permanent magnets of the escape wheel or / and all of the functional permanent magnets of the anchor having an overall magnetic moment oriented in a general direction of magnetization. According to the invention, the escape wheel or / and the anchor each further comprises / comprise at least one permanent magnet for compensating for said overall magnetic moment, said at least one permanent magnet for compensation being arranged so that the addition vector of the global magnetic moment with the compensation magnetic moment gives either a zero vector, or a resulting vector whose norm is lower than the norm of the global magnetic moment.
    In an advantageous variant, said at least one permanent compensation magnet is arranged so that, where appropriate, the norm of said resulting vector is less than half of the norm of the overall magnetic moment.
    In a preferred variant, the magnetic compensation moment is oriented in the general direction of magnetization and has a direction opposite to that of said overall magnetic moment. In addition, the norm of the compensating magnetic moment is substantially equal to the norm of the overall magnetic moment.
    [0010] Thanks to the magnetic compensating moment of said at least one permanent compensation magnet, a torque of parasitic force, generated by the overall magnetic moment of all the functional permanent magnets in a uniform external magnetic field and applying to the The rotating element considered (the escape wheel or the anchor), is at least partially compensated by a compensating force torque generated by the compensating magnetic moment in the uniform external magnetic field. In the preferred variant, the total force torque acting on the rotating element, when a uniform external magnetic field passes through the watch movement, has a low value which may be substantially zero. Parasitic friction forces which would act, in the absence of said at least one permanent compensation magnet, on the two pivots of the rotating element in their respective bearings in the presence of a magnetic field are thus greatly reduced, or even substantially canceled. external uniform generating on all the functional permanent magnets a torque of parasitic force whose vector is not axial.
    Brief description of the figures
    The invention will be described below in more detail with the aid of the accompanying drawings, given by way of non-limiting examples, in which:Figure 1 shows, in a simplified manner, a magnetic escapement of the prior art exhibiting the technical problem identified;Figure 2 shows the forces acting on the escape wheel of Figure 1 in the presence of a magnetic field external to the watch movement having a component perpendicular to the axis of rotation;Figure 3 is a simplified sectional view of a magnetic escape wheel according to the invention;Figure 4 is a simplified sectional view of an alternative magnetic escape wheel according to the invention; andFIGS. 5A and 5B are simplified cross-sectional and top views respectively of a magnetic anchor according to the invention.
    Detailed description of the invention
    In Figure 1 is shown, in a simplified manner, a magnetic escapement 2 fitted to a watch movement of the prior art and formed by an escape wheel 4 and an anchor 6. This watch movement has been shown in a field external magnetic BExt. The magnetic escape wheel 4 comprises a shaft 8 having at its two ends two pivots 10 and 11 respectively arranged in two bearings 12 and 13 which define an axis of rotation 9 for the escape wheel. This escape wheel conventionally comprises a pinion 14 for its drive by a barrel, generally via a kinematic chain formed of at least one mobile. It further comprises two non-magnetic plates 16 and 18 respectively carrying two annular magnetic tracks 20 and 22, formed by permanent magnets, which are magnetically coupled, in repulsion, to at least one magnetic paddle 34, also formed by at least one permanent magnet. , equipping the magnetic anchor 6. The two magnetic tracks 20, 21 and said at least one pallet 34 together form a magnetic system of the watch movement incorporating the magnetic escapement in question. Thus the permanent magnets forming the two magnetic tracks and said at least one permanent magnet forming said at least one magnetic paddle are called 'functional permanent magnets' by the fact that they actively participate in the magnetic system provided for contactless coupling of the wheel. escapement with anchor.
    The magnetic anchor further comprises a shaft 26 having at its two ends two pivots 28 and 29 respectively arranged in two bearings 30 and 31 which define an axis of rotation 27 for the magnetic anchor. Conventionally, the magnetic anchor comprises an arm 32 connecting the magnetic pallet 34 to the shaft 26 and a rod 36 having at its free end a fork 38 and a dart 39. It will be noted that, in the case where the anchor comprises two magnetic paddles carried respectively by two arms in the manner of a Swiss anchor, the section of Figure 1 is then made along a broken line passing through the two axes of rotation 9 and 27 and through one 34 of the two magnetic paddles which is outside the geometric plane comprising the two axes of rotation.
    In Figure 2 is shown a section of the escape wheel 4 in the X-Z plane. To visually expose the technical problem already indicated in the summary of the invention, the external magnetic field BExt has a non-zero component Bx. The magnetic tracks or magnet tracks 20, 21 both have a magnetization axis oriented along the Z axis and having the same direction, so the overall magnetic moment of the functional permanent magnets forming these two magnetic tracks or magnet tracks has a direction along the Z axis. It will be noted that each functional magnet carried by the escape wheel has a magnetic moment which can be defined mathematically as being the integral of the magnetization over the entire volume of this functional magnet. In the case shown, all of the functional permanent magnets of the escape wheel, namely those forming the two magnetic tracks, have an overall magnetic moment oriented along the axis of rotation 9 of the escape wheel, c ' that is to say along the Z axis.
    As indicated, we consider here a case where the escape wheel is located in an external magnetic field having a non-zero component Bx. When an external magnetic field BExt passes through the escape wheel, the overall magnetic moment of this escape wheel tends to align with the external magnetic field, analogous to the needle of a compass. In other words, an external magnetic field having a component Bx generates, for a rotating element having an overall magnetic moment whose component along its axis of rotation is non-zero, a moment of force whose vector has a component MY, according to the Y axis, which is non-zero. More generally, an external magnetic field having a non-zero radial component, relative to the axis of rotation of a rotating element provided with magnets, generates, when this rotating element has an overall magnetic moment, the component of which along its axis of rotation is non-zero, a moment of force on the rotating element whose vector presents a non-zero radial component MXY in the XY plane. This radial component MXYdu moment of force generated by the external magnetic field results in a radial force of each of the two pivots 10, 11 on the lateral surface of the hole of the respective bearing 12, 13 in which this pivot is arranged. The bearings then exert in reaction a normal force FN; which then generates a continuous friction of the pivots in the bearings and increases the overall friction of these pivots in their respective bearings. This represents a problem in terms of the operation of the magnetic escapement and a loss of mechanical energy, a problem which increases with the intensity of the external magnetic field and which can go as far as blocking the magnetic escapement in question.
    In Figure 3 is shown an embodiment of the invention for a watch movement equipped with an escape wheel similar to that in Figure 2. The references already described above will not be described again here. The escape wheel 42, forming a rotating element, comprises a permanent magnet 44 for compensating for the overall magnetic moment that all of the functional permanent magnets of this escape wheel have. In general, the compensating permanent magnet is arranged so that the vector addition of said overall magnetic moment with the compensating magnetic moment of this compensating permanent magnet gives either a zero vector or a resulting vector whose norm is lower. to the norm of the global magnetic moment. In a variant, the norm of said resulting vector is expected to be less than half of the norm of said overall magnetic moment. It will be noted that the permanent compensation magnet can interact with other elements of the watch movement and generate a certain disturbance on the operation of these other elements or of components carrying the rotating element in question or these other elements. Thus, it is possible that the watch designer chooses not to fully compensate a parasitic force couple which is applied to the rotating element considered and resulting from a coupling of said overall magnetic moment with a uniform external magnetic field.
    In a preferred variant, as in Figure 3, the magnetic compensation moment is oriented in the general direction (Z axis) of said overall magnetic moment and has a direction opposite to that of this overall magnetic moment. Then, the norm of the compensating magnetic moment is expected to be substantially equal to the norm of the overall magnetic moment. By “norm”, one understands the length of the vector considered, ie the absolute value of this length. We also sometimes speak of the intensity of the vector. Thus, in this text, 'length', 'norm', 'intensity' and 'value (absolute)' for a vector are synonyms.
    The permanent compensation magnet 44 is arranged so as not to prevent all of the functional permanent magnets of the escape wheel 42 from fulfilling their respective functions in the magnetic coupling system of this escape wheel with a magnetic anchor, for example similar to the magnetic anchor 6 in Figure 2. In an advantageous variant, the permanent compensation magnet is a ring-shaped magnet which is arranged around the pivoted shaft 8. In the variant shown in Figure 3, the annular compensation magnet is arranged under the two plates 16 and 18 on the side opposite to that of the drive pinion 14.
    In Figure 4 is shown a preferred variant. In this preferred variant, the escape wheel 52 comprises a permanent compensation magnet 44A which is also of annular shape and arranged around the shaft 8A of this escape wheel, against a shoulder of this shaft, but this magnet 44A is arranged here between the two plates 16 and 18 respectively carrying the two magnetized tracks 20 and 22. More particularly, the magnet 44A is arranged midway between the two plates. This configuration is more optimal in the case where the external magnetic field which passes through the magnetic escape wheel is not very uniform.
    In Figures 5A and 5B is shown an embodiment of the invention which relates to a magnetic anchor 62, which forms a rotating element provided with at least one functional permanent magnet. This magnetic anchor, apart from the permanent compensation magnet 44B, is similar to that of Figure 1. Thus, this magnetic anchor will not be described again here in detail. Figure 5A is sectioned in a general plane including the axis of rotation 27 and the longitudinal axis of the rod 36. Figure 5B is a top view, without the representation of the upper bearing. In this FIG. 5B, it can be seen that the magnetic anchor is similar to a conventional anchor of the Swiss type. It comprises two magnetic paddles formed respectively by two permanent magnets 34 and 35 which are respectively arranged at the ends of two arms 32 and 33. The two magnetic paddles constitute the set of functional permanent magnets of the anchor 62. The permanent magnets 34 and 35 both have an axial magnetization with the same polarity, so that the set of functional permanent magnets has, as for the magnetic escape wheel described above, an overall magnetic moment oriented along the Z axis (orientation of the rotation axis). Thus, according to a preferred variant of the invention, the permanent compensation magnet 44B has a magnetic axis along the axis of rotation and a reverse polarity with respect to that of the two permanent magnets 34, 35.
    The intensity of the magnetic field generated by the permanent compensation magnet 44B is selected in a manner similar to that described above for the permanent compensation magnet 44, 44A of the escape wheel 42 or 52. The magnet 44B is also annular in shape and arranged around the shaft 26 of the anchor. Preferably, this magnet 44B is arranged along the shaft 26 as close as possible to the general plane perpendicular to the axis of rotation and comprising the two magnets 34, 35 which participate in the magnetic coupling system of the magnetic anchor with a escape wheel, for example similar to that shown in Figures 3, 4.
    权利要求:
    Claims (9)
    [1]
    1. Watch movement comprising a magnetic escapement formed in part by an escape wheel (42; 52) which participates in a magnetic system of this magnetic escapement and which is provided with at least one functional permanent magnet (20, 22), the set of functional permanent magnets of the escape wheel having an overall magnetic moment oriented in a general direction of magnetization, this escape wheel further comprising at least one permanent magnet (44; 44A) for compensating for said overall magnetic moment , said at least one compensating permanent magnet being arranged so that the vector addition of the global magnetic moment with the compensating magnetic moment gives either a zero vector or a resulting vector whose norm is less than the norm of the global magnetic moment .
    [2]
    2. Watch movement according to claim 1, wherein the escape wheel comprises at least one plate (16) carried by a pivoted shaft (8, 8A), this plate being arranged perpendicularly to said axis of rotation (9) and bearing to its periphery of functional permanent magnets (20) among said set of functional permanent magnets, said at least one compensating permanent magnet (44, 44A) surrounding said rotated shaft.
    [3]
    3. Watch movement according to claim 2, wherein the escape wheel comprises two plates (16, 18) of non-magnetic material which are carried by said pivoted shaft, these two plates being arranged at a distance from one another. perpendicular to said axis of rotation (9) and each carrying at its periphery, on the side of an intermediate space between the two plates, functional permanent magnets (20, 22) forming said set of functional permanent magnets; characterized in that said permanent compensation magnet (44A) is arranged between the two plates substantially at the same axial distance therefrom.
    [4]
    4. Watch movement comprising a magnetic escapement formed in part by an anchor (62) which participates in a magnetic system of this magnetic escapement, this anchor comprising at least one magnetic pallet each formed by a functional permanent magnet (34, 35), the 'set of functional permanent magnets of this anchor having an overall magnetic moment oriented in a general direction of magnetization, this anchor further comprising at least one permanent magnet (44B) for compensating said global magnetic moment, said at least one permanent magnet for compensation (44B) being arranged so that the vector addition of the overall magnetic moment with the compensating magnetic moment gives either a zero vector or a resulting vector whose norm is less than the norm of the global magnetic moment.
    [5]
    5. Watch movement according to claim 4, wherein said at least one permanent compensation magnet (44B) surrounds a pivoted shaft (26) of the anchor.
    [6]
    6. Watch movement according to any one of the preceding claims, characterized in that said at least one permanent compensation magnet is arranged so that, where appropriate, said norm of said resulting vector is less than half of said norm of the global magnetic moment. .
    [7]
    7. Watch movement according to any one of the preceding claims, in which said magnetic compensating moment is oriented in said general direction of magnetization and has a direction opposite to that of said overall magnetic moment, the norm of the magnetic compensating moment being substantially equal to said. global magnetic moment norm.
    [8]
    8. Watch movement according to any one of the preceding claims, characterized in that said at least one permanent compensation magnet is arranged so as not to prevent said set of functional permanent magnets from fulfilling their respective functions in said at least one magnetic system.
    [9]
    9. Timepiece, in particular wristwatch, comprising a watch movement according to any one of the preceding claims.
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    同族专利:
    公开号 | 公开日
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    CH8542019|2019-06-26|
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