EP4020100A1 - Timepiece including a rotating bezel - Google Patents

Abstract

The timepiece comprises a rotating bezel, mounted on a caseband with N stable angular positions, and a magnetic device (20) composed of a first set of Z1 magnets (22) carried by the rotating bezel and a second set of Z2 magnets (24) carried by the caseband. The first and second sets of magnets are each arranged circularly so as to present between them a magnetic interaction generating on the rotating bezel a resistant magnetic torque, over at least part of an angular pitch, when this rotating bezel is driven in rotation from any one of the N stable angular positions. The numbers Z1 and Z2 are greater than one and less than N. The Z1 magnets and the Z2 magnets are angularly distributed so that the resistive magnetic torque exhibits a variation as a function of the stable angular position of the rotating bezel. Advantageously, this variation is periodic. Preferably, the variation takes place between substantially two non-zero values.

Description

Technical field of the invention

The present invention relates to the watchmaking field, in particular timepieces provided with a rotating bezel.

Technology background

We know from the patent application EP 2 998 799 a timepiece provided with a rotating bezel, the stable angular positions of which are defined by two rows of magnets arranged circularly one opposite the other, these two rows of magnets being fixed respectively to the rotating bezel and to a middle part supporting the rotating bezel. To obtain 60 stable angular positions enabling the rotating bezel to be positioned in 60 different positions corresponding to 60 minutes, provision is made in one variant for two rows of 60 magnets, i.e. 120 magnets, and in another variant a first row of 60 magnets and a second row with a lesser number of magnets, so as to reduce a resistive effort to pass from a stable angular position to a following one. This embodiment requires, in particular in the first variant, many magnets. Then, all the stable angular positions are similar, that is to say that the resistive force to go from one stable angular position to the next is identical for all the stable angular positions. No differentiation is provided, in particular to mark the positions corresponding to a multiple of five minutes, at the level of the force couple that a user who operates the rotating bezel must apply.

Summary of the invention

The object of the present invention is to solve the drawbacks mentioned in the technological background, and in particular to propose a timepiece provided with a rotating bezel with a magnetic device between the bezel and the casing part supporting this rotating bezel which is arranged in such a way that the resisting magnetic torque varies as a function of the stable angular position, c ie at least two levels/two different values for the plurality of stable angular positions provided. In addition, the present invention proposes to achieve the aforementioned object by means of a magnetic device which is not very complex, relatively inexpensive and compact, and which is easily realizable in a case with conventional dimensions for a watch with a rotating bezel. .

To this end, the present invention relates to a timepiece comprising a rotating bezel mounted on part of a casing of this timepiece and operable in rotation by a user, this rotating bezel having N stable angular positions, N being an integer greater than two, which have between them an angular pitch α equal to 360° divided by N (α = 360°/N). Next, the timepiece comprises a magnetic device composed of a first set of first pole parts carried fixedly by the rotating bezel and of a second set of second pole parts carried fixedly by the covering part. The first set of first pole parts and the second set of second pole parts are each arranged circularly so that the first pole parts have a magnetic interaction with the second pole parts which generates on the rotating bezel a resistant magnetic torque when this rotating bezel is driven in rotation, at least in a given direction, from any one of the N stable angular positions towards a following stable angular position, that is to say adjacent, this resistive magnetic torque being exerted on at least part of the angular path , equal to an angular step, which separates these two stable angular positions.

The timepiece according to the invention is characterized in that the number Z1 of first pole parts is greater than one and less than N (1<Z1<N) and the number Z2 of second pole parts is also greater than one and less than N (1 < Z2 < N); and in that the first set of Z1 first pole parts is distributed among N first angular positions, linked to the rotating bezel and having said angular pitch between them, with at most one first pole part per first angular position, and the second set of Z2 second pole parts is distributed among N second angular positions, linked to said casing part and having between them said angular pitch, with at most one second pole part per second angular position, so that said resistive magnetic torque has a variation in function of the stable angular position of the rotating bezel, among the N stable angular positions, at least according to said given direction for the rotation of this rotating bezel.

The expression “resistant magnetic torque” is understood as being a resistant torque exerted on the rotating bezel which results from the magnetic forces between the two sets of pole parts. Thus, this resistive magnetic torque can be formed at least in part by a resistive torque originating from a frictional force between the rotating bezel and a casing part which results from said magnetic forces.

According to a general embodiment of the invention, the first pole parts are magnetically similar and the second pole parts are magnetically similar. Then, the numbers Z1 and Z2 are selected and the distribution of the first set of Z1 first pole parts, among the N first angular positions, as well as the distribution of the second set of Z2 second pole parts, among the N second angular positions, are carried out so that said variation of the resistive magnetic torque is periodic.

According to a preferred embodiment of the invention, the magnetic device is arranged so that the periodic variation of the resistive magnetic torque has an angular period equal to an integer K of angular steps, this integer K being greater than one and selected so that the division of the integer N by the number K is equal to a positive integer M. Then the numbers Z1 and Z2 are selected and said distribution of the first set of Z1 first pole parts together with the distribution of the second set of Z2 second pole parts are made so that said variation of the resistive magnetic torque has, for said given direction of rotation of the rotating bezel, substantially two distinct non-zero values.

Various embodiments and various advantageous variants will be presented in the detailed description of the invention which follows.

Brief description of figures

• la Figure 1 est une coupe transversale partielle d'une montre selon un premier mode de réalisation de l'invention;
• la Figure 2 montre, de manière simplifiée, une première variante d'un dispositif magnétique associé à la lunette tournante de la montre de la Figure 1 avec, d'une part, un premier ensemble de premières parties polaires qui sont solidaires de la lunette tournante ou d'une carrure qui la supporte et, d'autre part, un deuxième ensemble de deuxièmes parties polaires qui sont solidaires de l'autre de ces deux parties d'habillage de la montre;
• la Figure 3 est une représentation linéaire schématique de la première variante du dispositif magnétique de la Figure 2;
• la Figure 4 montre, de manière simplifiée, une deuxième variante du dispositif magnétique associé à la lunette tournante de la montre de la Figure 1 ;
• la Figure 5 montre, de manière simplifiée, une troisième variante du dispositif magnétique associé à la lunette tournante de la montre de la Figure 1 ;
• la Figure 6 est une coupe transversale partielle d'une montre selon un deuxième mode de réalisation de l'invention;
• la Figure 7 montre, de manière simplifiée, une première variante d'un dispositif magnétique associé à la lunette tournante de la montre de la Figure 6 avec, d'une part, un premier ensemble de premières parties polaires qui sont solidaires de la lunette tournante ou d'une carrure qui la supporte et, d'autre part, un deuxième ensemble de deuxièmes parties polaires qui sont solidaires de l'autre de ces deux parties d'habillage de la montre;
• la Figure 8 est une représentation linéaire schématique de la première variante du dispositif magnétique de la Figure 7;
• les Figures 9 et 10 montrent, de manière simplifiée, une deuxième variante et une troisième variante du dispositif magnétique associé à la lunette tournante de la montre de la Figure 6, ces variantes étant magnétiquement équivalentes à la première variante des Figures 7 et 8.

The invention will be described below in more detail using the accompanying drawings, given by way of non-limiting examples, in which:

• the Figure 1 is a partial cross-section of a watch according to a first embodiment of the invention;
• the Figure 2 shows, in a simplified manner, a first variant of a magnetic device associated with the rotating bezel of the watch of the Figure 1 with, on the one hand, a first set of first pole parts which are fixed to the rotating bezel or to a middle part which supports it and, on the other hand, a second set of second pole parts which are fixed to the other of these two casing parts of the watch;
• the Figure 3 is a schematic linear representation of the first variant of the magnetic device of the Figure 2 ;
• the Figure 4 shows, in a simplified manner, a second variant of the magnetic device associated with the rotating bezel of the watch of the Figure 1 ;
• the Figure 5 shows, in a simplified manner, a third variant of the magnetic device associated with the rotating bezel of the watch of the Figure 1 ;
• the Figure 6 is a partial cross-section of a watch according to a second embodiment of the invention;
• the Picture 7 shows, in a simplified manner, a first variant of a magnetic device associated with the rotating bezel of the watch of the Figure 6 with, on the one hand, a first set of first pole parts which are fixed to the rotating bezel or to a middle part which supports it and, on the other hand, a second set of second pole parts which are fixed to the other of these two casing parts of the watch;
• the Figure 8 is a schematic linear representation of the first variant of the magnetic device of the Picture 7 ;
• them Figures 9 and 10 show, in a simplified manner, a second variant and a third variant of the magnetic device associated with the rotating bezel of the watch of the Figure 6 , these variants being magnetically equivalent to the first variant of the Figure 7 and 8 .

Detailed description of the invention

With reference to Figures 1 to 5 , a first embodiment of a timepiece according to the invention will be described. The watch 2 comprises a case 4 provided with a rotating bezel 6, which can be rotated by a user, and a magnetic device 20 associated with this rotating bezel. The rotating bezel and the magnetic device are arranged so that the rotating bezel can be positioned in sixty angular positions which have between them an angular pitch α equal to 6° (equal to 360°/60). Thus, a reference point of the rotating bezel can be positioned at any minute of a minute scale centered on the axis of rotation of the rotating bezel, as is customary for a mechanical or electromechanical watch which is equipped with a rotating bezel. It will be noted that, in general, the invention applies to N stable angular positions, N being an integer greater than two, which have between them an angular pitch α equal to 360° divided by N (α = 360°/ NOT).

The rotating bezel 6 is mounted on a middle part 8, forming a casing part of the watch, and held in place by means of a spring 10 inserted partly into an internal lateral groove of the middle part and partly into a lateral groove inside the rotating bezel. To the Figure 1 a glass 12 is also partially shown, carried by a fixed internal bezel formed by an upper part of the middle part 8, as well as a frustoconical flange 14 and a dial 16 arranged on a movement 18. The magnetic device 20 is arranged at the inside case 4 of the watch and is composed of a first set of first pole parts 22, which are fixedly arranged in the rotating bezel 6, and of a second set of second pole parts 24 which are fixedly arranged in the middle part 8 More specifically, the first set of first pole parts 22 and the second set of second pole parts 24 are each arranged circularly and generally opposite each other so that the first pole parts have a magnetic interaction with the second pole parts, this magnetic interaction generating on the rotating bezel a non-zero resistant magnetic torque when this rotating bezel is subjected to a rotation drive ple, in one direction or the other, from any of the sixty stable angular positions. It will be noted that the bezel here is bidirectional, that is to say rotating in both directions. Alternatively, the bezel may be unidirectional, so that it then only rotates in a given direction.

According to a general variant of the invention, the first pole parts are magnetically similar and the second pole parts are also magnetically similar. The first embodiment is characterized in that the first set of first pole parts and the second set of second pole parts are formed from materials generating a magnetic attraction between this first set and this second set. Then, the N stable angular positions each correspond by positioning first pole parts respectively opposite second pole parts. In the absence of a mechanical device associated with the magnetic device, the angular positioning of the rotating bezel is obtained thanks to the magnetic device which generates a restoring torque on the rotating bezel around each of its stable angular positions. It will be noted that, in embodiments not described here in detail, it is possible to associate a mechanical device with the magnetic device to precisely obtain the stable angular positions of the rotating bezel, such a mechanical device being able to participate in a restoring force to each stable angular position.

In a first main variant shown in the figures, the first set of first pole parts 22 and the second set of second pole parts 24 are both formed of permanent magnets, the second set of magnets 24 being arranged in magnetic attraction with the first set of magnets 22. In a second main variant, not shown, one set among the first set of first pole parts and the second set of second pole parts is formed of permanent magnets, while the other set is formed of parts in ferromagnetic material. The first main variant is advantageous in that the magnetic attraction force can be higher than in the second main variant for identical permanent magnets. The second main variant can be interesting because it makes it possible to reduce the cost and the size of the magnetic device in the axial direction, the ferromagnetic parts may have a relatively small height. In the variant shown in Figure 1 , the arrangement of the magnets 22 and the magnets 24 is axial, that is to say that they are aligned in the direction of the axis of rotation of the rotating bezel and that the orientation of the magnetic axes of these magnets is substantially parallel to this axis of rotation.

An axial arrangement of the two sets of pole parts, globally generating a force of attraction between the rotating bezel 4 and the middle part 8, has the advantage of pressing the rotating bezel against the middle part and thus participating in holding the bezel in place. rotating. One could thus theoretically eliminate the spring 10 which holds the bezel assembled to the caseband. In practice, it is preferable to keep the spring for safety reasons. However, the axial force of this spring on the bezel can be provided relatively low, or even zero, so that the static friction force, then the dynamic friction force to be overcome during actuation of the rotating bezel is low. If the frictional force between the rotating bezel and the middle part is too high, this frictional force can then lead, when a return torque towards each stable angular position is insufficient to overcome the resistive torque generated by this frictional force, to imprecise angular positioning of the rotating bezel in the stable angular positions provided. To prevent the axial magnetic force from disturbing, via the frictional force that it generates, a precise angular positioning of the rotating bezel, provision can be made for the spring 10 to be arranged so as to exert on the rotating bezel an axial force in the direction contrary to the axial magnetic force. As already indicated, it is possible to associate the magnetic device with a complementary mechanical device to obtain precise positioning of the rotating bezel in the stable angular positions provided. To solve the problem indicated here, in another variant of the first embodiment, the two sets of magnets are arranged in the same general plane with a radial orientation of their respective magnetic axes (in a similar way to the variant of the second embodiment shown in Figure 6 ). It should be noted that in a particular variant, the two sets of pole parts are arranged obliquely so as to be able to thus adjust the value of an axial magnetic force applied to the rotating bezel.

It can therefore be seen that in variants with an axial or oblique arrangement of the two sets of pole parts having a magnetic attraction between them, two components of the magnetic forces acting on the pole parts of the first set associated with the rotating bezel are to be considered in the arrangement of the rotating bezel and the magnetic device, namely the axial component and the tangential component. The axial component, if it is not compensated, generates a friction force between the rotating bezel and the middle part which always opposes the rotational movement of this bezel and thus generates part of a first resistant magnetic torque which is exerts over the entire angular path, i.e. over an angular step, of the rotating bezel between any two adjacent stable angular positions (that is to say between any stable angular position and a next stable angular position in the direction of rotation of the rotating bezel). The tangential component defines a magnetic restoring torque which tends to position the rotating bezel in one or the other of the stable angular positions provided and which forms a second resisting magnetic torque over only a first part of the aforementioned angular path. Indeed, on a second part of the angular path, the tangential component of the magnetic forces exerted respectively on the pole parts of the first set of pole parts changes direction and then generates a drive torque towards the next angular position. Thus, on the first part of said angular path, a resistant magnetic torque is still applied overall to the rotating bezel, while on the second part of this angular path the overall magnetic torque (that is to say resulting from the magnetic forces between the two sets of pole parts) can be resistant on a first angular zone and become catchy on a second angular zone if the magnetic return torque becomes greater than the friction torque of magnetic origin.

In general, the magnetic device according to the invention is characterized in that the number Z1 of first pole parts in the first set is greater than one and less than N (i.e. 1<Z1<N) and the number Z2 of second parts polars in the second set is also greater than one and less than N (i.e. 1<Z2<N). Then, the first set of Z1 first pole parts is distributed among N first angular positions, linked to the rotating bezel and having said angular pitch between them, with at most one first pole part per first angular position, and the second set of Z2 second pole parts is distributed among N second angular positions, linked to the middle part and having said angular pitch between them, with at most one second pole part per second angular position, so that the resistive magnetic torque generated by the magnetic device presents a variation in function of the stable angular position of the rotating bezel, among the N stable angular positions, at least in a given direction for the rotation of this rotating bezel.

The variation of the resistant magnetic torque according to the invention is not related to the angular distance of the rotating bezel, within an angular pitch, from any stable angular position, but this variation is related to the stable angular position itself, that is to say that the resisting magnetic torque during an actuation in rotation of the rotating bezel from a stable angular position to a following stable angular position, for a zero distance and/or at least a certain distance given within the angular pitch separating these two stable angular positions, varies according to the stable angular position from which the actuation in rotation is carried out, at least for a given direction of rotation. Indeed, the resistive magnetic torque generated by the magnetic device 20 varies, from any angular position stable, depending on the distance of the bezel relative to this stable angular position in the patent application EP 2 998 799 . But this is not the variation that is the subject of the main characteristic of the present invention, because this variation of the resistive magnetic torque is a variation felt by the user when passing between a first stable angular position and a following stable angular position relative to the passing between a second stable angular position and a following stable angular position. The variants described below will make it possible to clearly understand the variation of the resistive magnetic torque which relates to the present invention.

In the variants of the magnetic device according to the invention which will be described below, the number Z1 of first pole parts and the number Z2 of second pole parts are selected and the distribution of these Z1 first pole parts, among the N first angular positions linked to the bezel, as well as the distribution of these Z2 second pole parts, among the N second angular positions linked to the middle part, are produced such that the variation of the resistive magnetic torque is periodic, that is to say that it repeats after a certain number of angular steps.

The periodic variation of the resistive magnetic torque has an angular period β equal to an integer K of angular steps, i.e. β = K α, this integer K being greater than one (K> 1) and selected so that the division of the whole number N by the number K is equal to a positive whole number M (that is M = N/K). Preferably, the numbers Z1 and Z2 are selected and said distribution of the first set of Z1 first pole parts as well as said distribution of the second set of Z2 second pole parts are made such that the variation of the resistive magnetic torque presents, for at least one given direction of rotation of the rotating bezel, only two distinct non-zero values. The angular period β of the variation of the resistive magnetic torque is advantageously provided equal to five times the angular pitch α, ie β=5·α. Preferably, the magnetic device is arranged so that the resistive magnetic torque is again stronger after a rotation equal to the angular period (i.e. every five minutes), that is to say every 30° during a rotation of the rotating bezel.

With reference to Figure 2 and 3 , the magnetic device 20 incorporated in a first variant of the first embodiment according to the invention will be described more particularly. In this first variant, as in the other variants which will be described subsequently, the number N of stable angular positions P _v , where v=1 to N, of the rotating bezel is equal to sixty (N=60) and the number K is equal to five (K=5). Thus the number M is an even number, equal to twelve (M=12). It should be noted that the number N of stable angular positions P _v corresponds to the number N of angular positions which is provided for the placement of the pole parts of the bezel and also for the placement of the pole parts of the middle part.

It will be noticed that the Figure 2 (like the similar Figures which will be described later) has a simplified representation, separately, of the rotating bezel 6 and of the middle part 8, in order to be able to clearly represent the circular arrangement of the pole parts 22 in the bezel and of the parts 24 poles in the middle. In the variant shown in Figure 2 and 3 , all the pole parts 22 and 24 are formed by substantially identical magnets, each magnet 22 being arranged in magnetic attraction relative to the magnets 24 when this magnet 22 is placed opposite any magnet 24. It will also be noted that the Figure 3 (like the Figure 8 which is similar) is a partial linear representation of the magnetic device 20 of the Figure 1 . The Figure 3 corresponds to the arrangement of the magnets 22 and 24 in a cylindrical surface with an axial orientation of these magnets (La Figure 8 corresponds to the arrangement of the magnets in a general plane perpendicular to the axis of rotation of the rotating bezel, with a radial orientation of these magnets as shown in Figure 6 ).

In the first variant of the first embodiment, the number Z2 of magnets 24 is equal to M which is twelve, that is Z2=M=N/K=12, and these twelve magnets are distributed regularly with an angular period β=K α = 30°. In other words, the twelve magnets 24 are placed in a series S5 of twelve angular positions linked to the middle part (that is to say in a reference frame of polar coordinates linked to the middle part) and having between them the angular period β = 30°. The number Z1 of magnets 22 is equal to M+[K-1]·M/2, i.e. Z1=12+4·6=36. A subset of twelve magnets 22 is placed in a first series S0 of twelve positions angular linked to the bezel (that is to say in a reference frame of polar coordinates linked to the bezel) and having between them the angular period β=30°. The remaining twenty-four magnets 22 are distributed so that four subsets of six magnets are respectively placed in the four other series S1, S2, S3, S4 of twelve angular positions which are also linked to the bezel (i.e. that is to say in the reference frame of polar coordinates linked to the telescope) and which also have between them the angular period β=30°. These four other series and the first series are angularly offset from each other by the angular pitch α=360°/N=6°. These twenty-four remaining magnets 22 are advantageously distributed in the four series S1 to S4 in a regular manner, presenting between them an angular distance or an interval equal to twice the angular period (2·β).

It will be noted that, given that the magnets Z1 of the first set are placed among N angular positions having between them the angular pitch α = 360°/N, only K distinct series of M angular positions having between them the angular period β = K α, with M = N/K, exist. These K distinct series are angularly offset from each other by the angular pitch α. The arrangement of the magnetic device according to the first variant makes it possible to obtain only two distinct non-zero values for the resistive magnetic torque (namely two maximum values of the resistive magnetic torque on an angular path of one angular pitch between two adjacent stable angular positions ) when applying a torque drive on the rotating bezel from one or other of its stable angular positions, namely a first value when the series S5 of magnets 24 of the rotating bezel is initially located opposite the series S0 of magnets 22 of the case middle (as shown in Figure 3 ), which corresponds to an initial positioning of the rotating bezel in any one of the stable angular positions P _0+nK with n=0 to 11, and a second value, lower than the first value, when the series S5 of magnets 24 is initially located opposite one or the other of the series S1 to S4, which corresponds to an initial positioning of the rotating bezel in any one of the stable angular positions P _q+nK with q = 1 to 4 and n = 0 to 11. There is therefore a variation of the resistive magnetic torque, that is to say of its intensity, as a function of the stable angular position in which the rotating bezel is initially located. In the example given, given that the series S1 to S4 comprise half as many magnets 22 as the series S0, the resistive magnetic torque varies substantially by a factor of two, the second value mentioned above being substantially equal to half of the first value mentioned above.

It will be noted firstly that either the series S5 of magnets, or the five series S0 to S4 of magnets may/may, in another variant, be replaced by parts made of ferromagnetic material. Thus, in a particular variant, the first set of pole parts associated with the rotating bezel is formed by the toothing of a crown made of ferromagnetic material from which a few teeth have been removed to obtain a profile similar to that of the upper part shown in Figure 3 . It will be noted that the empty holes can be eliminated in a variant of the Fig. 3 . It will then be noted that it is possible to reverse the arrangement of the pole parts, that is to say that the first set of pole parts can be linked to the caseband while the second set of pole parts can be linked to the rotating bezel without this changing the operation of the magnetic device. Thus, in a variant, the S5 series can be composed of magnets 22 arranged in the rotating bezel, the S0 series to S4 then being composed of magnets 24 arranged in the caseband. It will also be noted that, in several variants to the first variant described above, the batch of six magnets 22 placed in each of the four series S1 to S4 can be placed according to all the possibilities of placing six identical magnets among the twelve angular positions of the series considered. It will also be noted that the four subsets of magnets placed respectively in the four series S1 to S4 can each have the same number of magnets different from M/2 = 6 provided that this number is less than the number M, and so always fulfill the condition linked to the variation of the resistive magnetic torque according to the invention. It will finally be noted that, in another less advantageous variant, it is possible to place fewer than M magnets in the series S0, provided that the number of magnets in the other series S1 to S4 remains lower than that of the series S0.

The various preceding remarks lead us to formulate a general variant covering the first variant described above. In this general variant, one of the two numbers Z1 and Z2 is equal to M (M = N/K) and the M corresponding pole parts, constituting the relevant set of pole parts, are distributed regularly, having between them the angular period β , while the other of the two numbers Z1 and Z2 is equal to M+[K-1] Y, where Y is a positive integer less than M and K is the number of angular steps in the angular period. Next, a subset of M pole parts, which correspond to said other of the two numbers Z1 and Z2 and are pole parts of the set relating thereto, are placed in a first series of M respective angular positions having between them the angular period . Finally, the remaining [K-1] Y pole parts are distributed in such a way that Y pole parts are placed in each of K-1 other series of M angular positions having between them the angular period β, the first series and the K- 1 other series being angularly offset from each other by said angular pitch.

In a particular variant of the general variant described above, the number M is an even number and the number Y is equal to M/2. Furthermore, the Y pole parts placed in each of said K-1 other series are preferably distributed regularly with intervals between them equal to twice the angular period, ie 2·β.

With reference to the Figure 4 , a second variant of the first embodiment of the invention will be described, which makes it possible to increase the magnetic coupling between the bezel and the caseband, without increasing the size of the magnetic device. In this second variant, as in the first variant shown in Figure 2 , the number N of angular positions is equal to sixty (N=60) and the number K for the angular period of variation of the resistive magnetic torque is equal to five (K=5). The magnetic device 20A is characterized in that one of the two numbers Z1 and Z2, defined above, is equal to twenty-four (Z1=24) and the twenty-four corresponding pole parts 24 are arranged in a first series S5 and a second series S6 of each twelve angular positions having between them the angular period β = 30°, these first and second series being offset by the angular pitch α, while the other of the two numbers Z1 and Z2 is equal to thirty-six (Z2 = 36), as in the example shown for the first variant, and three subsets of each twelve corresponding pole parts 22 are respectively placed in three series of each twelve angular positions having between them the angular period β, namely a third S0 series, a fourth S1 series and a fifth S3 series. The third and fourth series are offset, relative to each other, by the angular pitch α while the fifth series is offset by two angular pitches, ie by 2·α, relative to each of these third and fourth series. The other two remaining series, each with twelve angular positions presenting between them the angular period, are empty, that is to say without pole parts.

Thus, we obtain twenty-four magnets opposite twenty-four other magnets or, in a variant, opposite twenty-four ferromagnetic parts for the stable angular positions with high resistive magnetic torque, which have between them the angular period β, but twelve magnets in front of twelve other magnets or, in the variant, of twelve ferromagnetic parts for the stable angular positions with less resistant magnetic torque, which are located between the stable angular positions with high resistant magnetic torque. There is therefore a ratio of 1/2, for the number of pairs of opposite pole parts, between the stable angular positions with a lower resistive magnetic torque and the stable angular positions with a high resistive magnetic torque; which leads to approximately the same ratio for the intensity of the resistive magnetic torque as in the example shown for the first variant. It will be noted that, in another variant, this ratio can be reduced by adding subsets of pole parts in the two series of empty angular positions mentioned above, the number of pole parts per added subset being identical to and less than M, be less than twelve.

In a third variant, not shown in the figures but equivalent to the second variant, also with the number N equal to sixty (N=60) and the number K equal to five (K=5), one of the two numbers Z1 and Z2 is equal to twenty-four and the twenty-four corresponding pole parts are arranged in a first series and a second series of each twelve angular positions having between them the angular period β, these first and second series being offset by two angular pitches, i.e. by 2 α, while the other of the two numbers Z1 and Z2 is equal to thirty-six and three subsets of each twelve corresponding pole parts are respectively placed in a third series, a fourth series and a fifth series of each twelve angular positions having between them the angular period β. In this case, the fourth series is shifted by the angular pitch α with the third series and also with the fifth series. The other two remaining series, with each twelve angular positions having between them the angular period, are empty, that is to say without pole parts. As for the second variant, it is possible, in another variant, to modify the variation of the resistive magnetic torque by placing subsets of pole parts in the two aforementioned empty series, the number of pole parts per added subset being identical to and less than M, ie less than twelve, and for example equal to six or four regularly distributed pole parts.

The second variant and the third variant are very advantageous because, with only 25% of additional pole parts compared to the first variant, it is possible to approximately double the intensity of the resistive magnetic torque without other magnetic means than two sets of pole parts each distributed on the along a circle and respectively associated with the rotating bezel and the caseband. In other words, for a certain resistant magnetic torque given for a watch with a rotating bezel, with essentially two intensity values provided for this given resistant torque as a function of the stable angular position, it is possible to reduce the dimensions of the parts polar relative to the first variant, and therefore the size of the magnetic device. Note that variants similar to the second and third variants exist for other odd values of the number K.

Variants with essentially two intensity values for the resistive magnetic torque exist with more than two series of M pole parts on each of the two parts (the bezel and the middle part) with the same distribution among the N angular positions, and with series complementary pole parts on only one of these two parts. For example, for N equal to sixty (N = 60) and K equal to ten (K = 10), we can have, for each of the two parts, three subsets of six pole parts (M=N/K=6 ) which are placed respectively in three adjacent series, each having six angular positions presenting between them a angular period, and four other sub-assemblies of six pole parts which are placed respectively in four series, each having six angular positions presenting between them the angular period, among the seven series of six angular positions remaining on only one of these two parts, these four other series forming two pairs of adjacent series, each pair of adjacent series being surrounded by two empty series, that is to say without pole parts. Eighteen pole parts of one of the two parts opposite eighteen pole parts of the other part are thus obtained for six stable angular positions separated by an angular period of 60°, and twelve pole parts of one of the two parts which are located opposite twelve pole parts of the other part in the other stable angular positions. A ratio of approximately 2/3 is thus obtained between the two values of the resistive magnetic torque.

A fourth variant, less advantageous in terms of efficiency of the magnetic device, is shown in Figure 5 . This fourth variant relates, as in the first variant, to a case in which the integer number K of angular steps exhibited by the periodic variation of the resistive magnetic torque is equal to five (K=5). This fourth variant differs from the first variant in that the magnetic device 20B has a number Z2 of pole parts 24 which is divided by two, this number Z2 thus being equal to M/2, i.e. six (Z2=M/ 2 = 6). These six pole parts are regularly distributed with an angular distance/interval which is equal to twice the angular period, i.e. equal to 2 β. The number Z1 of pole parts 22 is identical to the corresponding number of the example represented for the first variant (Z1=36) and the distribution of these Z1 pole parts 22 responds to the general case of this first variant described above, but with a condition additional relative to this general case which is as follows: The series of angular positions S1 to S4 (those comprising less than M pole parts in the first variant) each comprise M/2 pole parts in this fourth variant (as in the example shown of the first variant), these six parts poles being distributed by pair of pole parts having between them, in the series concerned, an angular offset equal to an odd number, less than M/2, multiplied by the angular period. There are thus three pairs of magnets 22 each having between their two magnets the aforementioned angular offset. It is therefore understood that other configurations than that of the Figure 5 can be considered. It will be noted that in another variant, the number of pairs of pole parts in each of the series S1 to S4 can be provided less than three, namely equal to two or one. In the latter case, there is an increase in the ratio of resistive magnetic torques between the periodic angular positions of the rotating bezel exhibiting a certain resistive magnetic torque and those exhibiting a lower resistive magnetic torque, which is then lower in the case where the number of pairs of pole parts is equal to three and where said ratio is equal to two.

With reference to Figures 6 to 10 , a second embodiment of the timepiece according to the invention will be described. This second embodiment is characterized in that the first set of first pole parts and the second set of second pole parts are each formed of permanent magnets generating a magnetic repulsion between this first set and this second set; and in that the N stable angular positions of the rotating bezel 6A are each defined by a positioning of the N first angular positions, in which the magnets 22A integral with this rotating bezel are placed, with an angular offset equal to substantially half of said pitch angular (a/2) relative to the N second angular positions of the middle part 8A in which the magnets 24A fixed to this middle part are placed.

In the variant shown in Figure 6 , the watch 32 comprises a case 34 which is formed of a middle part 8A and a rotating bezel 6A. The references already described in connection with the Figure 1 relate to similar items. The construction of the case differs from that of the Figure 1 essentially by the fact that the rotating bezel is mounted on a ball bearing 36 and by the fact that the magnetic device 20C comprises a first set of magnets 22A and a second set of magnets 24A which are each arranged circularly in the same plane general of the case 34, this general plane being perpendicular to the axis of rotation of the rotating bezel. As already mentioned previously, such an arrangement makes it possible to eliminate the axial magnetic forces. In addition, a periodic arrangement of the magnets in each of the first and second sets of magnets, with an identical period or a second period equal to a positive integer number of times the first period, makes it possible to make the radial magnetic force zero or very weak. global for any angular position of the rotating bezel, so that the ball bearing is not or only slightly disturbed in its operation by friction forces. The magnetic devices of the variants shown in Figures 7 to 10 present the aforementioned periodic arrangement of the magnets, so that in these variants, only the tangential magnetic forces between the two sets of magnets are effective and generate the desired resistive magnetic torque, which corresponds to a magnetic return torque.

Given that the first set of magnets is arranged in magnetic repulsion relative to the second set of magnets, the magnetic potential energy is higher when the magnets of these two sets are facing each other. In the absence of mechanical positioning of the rotating bezel, the stable angular positions of the rotating bezel correspond to positions of lower magnetic potential energy in the magnetic device 20C. These stable angular positions therefore correspond to angular positions where the first and second sets of magnets are substantially offset by half an angular pitch relative to each other. It should be noted that in the absence of mechanical positioning, some of the stable angular positions risk not being very precise, that is to say not being perfectly periodic, in particular each stable angular position of the rotating bezel which precedes a stable angular position having a relatively high resistive magnetic torque and the one which follows this last stable angular position. Thus, in a particular variant, it is possible to provide, in addition to the magnetic device 20C, a mechanical device for angular positioning of the rotating bezel, for example a toothed wheel/crown fixed to the bezel and associated with a jumper integral with the middle part.

With reference to Figure 7 and 8 , a first variant of the second embodiment will be described. As for the variants of the first embodiment, the number N of stable angular positions of the rotating bezel 6A corresponds to the number of first angular positions linked to the rotating bezel and to the number of second angular positions linked to the middle part for the arrangement of the magnetic device 20C, this number N being equal to sixty (N=60) and the number K, defined previously, is equal to five (K=5). The caseband 8A comprises a series of twelve magnets 24A (Z2=M=N/K=12) placed in a series S5 of twelve angular positions having between them the angular period β=30°. The rotating bezel 6A comprises two subsets of twelve magnets 22A placed in two adjacent series S0 and S4 of twelve angular positions having between them the angular period β. These two subsets of magnets 22A define twelve stable angular positions in which the rotating bezel undergoes a relatively strong resistant magnetic torque during a drive in one direction of rotation or the other, these twelve stable angular positions occurring when the twelve magnets 24A linked to the rotating bezel are respectively located between the twelve pairs of adjacent magnets 22A formed by the two sub-assemblies placed in the series S0 and S4. What is very interesting in this second embodiment stems from the fact that the magnetic device 20C generates a high magnetic potential barrier on one side and on the other of the twelve stable angular positions of the rotating bezel which present a strong magnetic torque. resistant, namely a strong magnetic return torque which is generated by the tangential magnetic forces in the magnetic device 20C. Three other subsets of magnets 22A, each formed of six magnets, are distributed respectively in three other series S1, S2 and S3 of angular positions, each in a regular manner with an angular distance equal to twice the angular period. Thus, the number Z1 of magnets carried by the rotating bezel is equal to forty-two (Z1=42). Given that these three other series S1 to S3 comprise half as many magnets as the series S0 and S4, the resistive magnetic torque (equal to the magnetic restoring torque in the realization of the Figure 6 ) is substantially halved when the rotating bezel is driven between two stable angular positions of lesser magnetic torque resistance relative to a drive from a stable angular position of lesser magnetic torque resistance to a stable angular position with a high magnetic resistance torque or vice versa .

In the context of the first embodiment with a magnetic device provided with magnetic attraction, the resistive magnetic torque felt, when one arrives with the rotating bezel at a stable angular position exhibiting a strong resistive magnetic torque, is not the same as that felt when leaving such a stable angular position. Indeed, in this first embodiment, when approaching a stable angular position with a strong restoring torque, the resistive magnetic torque passes through a maximum before decreasing and finally becoming a driving torque insofar as the friction forces are not too great. On the other hand, when the rotating bezel is driven in rotation from a stable angular position with a high resistive magnetic torque, the user then feels this strong resistive magnetic torque which opposes the rotational movement of the rotating bezel. It is therefore necessary to have arrived in such a stable angular position in order to be able to feel that it is associated with a strong resistive magnetic torque. It should be noted that the same applies, to a lesser extent, for all the stable angular positions of the rotating bezel in the first embodiment.

The second embodiment provides an effective solution to the aforementioned problem which occurs in the first embodiment, thanks to the fact that a relatively high magnetic potential barrier is located before and after each of the twelve stable angular positions having a high restoring torque. magnetic. When a user activates the rotating bezel, he thus has the same feeling when this rotating bezel takes an angular step to arrive in a stable angular position having a strong magnetic return torque as when the rotating bezel takes an angular step starting from such a stable angular position. The same applies when a user operates the rotating bezel between stable angular positions of lesser resistive magnetic torque. On the other hand, it will be noted that a lower resistive magnetic torque appears only in one direction of rotation for the stable angular positions which are adjacent to a stable angular position with a strong resistive magnetic torque, and this in the direction which moves away from this last stable angular position. Indeed, in the other direction, the rotating bezel rotates in the direction of the adjacent stable angular position which has a high resistive magnetic torque and this rotating bezel is therefore subject to a high magnetic potential barrier.

To Figure 7 , 9 and 10 the three equivalent alternatives are given, corresponding to three configurations of the magnetic device 20C, respectively 20D and 20E, with forty-two magnets 22A carried by the rotating bezel. These three alternatives are magnetically similar, that is to say they generate the same resistive magnetic torque for each stable angular position of the rotating bezel. It will be noted that in other variants having a different level of magnetic coupling for the stable angular positions of lesser resistive magnetic torque, it is possible to provide more or fewer magnets 22A in the series S1, S2 and S3 while maintaining the same number of magnets in each of these series which is less than M, or here twelve. In other variants less effective for the resistive magnetic torque intervening in relation with the stable angular positions at high resistive magnetic torque, it is possible to reduce the number of pairs of adjacent magnets in the series S0 and S4, while having fewer magnets in each of the intermediate series S1 to S3. It should be noted that in the latter case, it is not necessary to have pairs of adjacent magnets in the series S0 and S4, because it suffices to provide the same number of magnets in each of these two series.

The three alternatives of the variant described previously can be generalized in the following terms: One of the two numbers Z1 and Z2 of magnets is equal to M (M = N/K) and the M corresponding magnets are distributed regularly by presenting between them intervals equal to the angular period (β), while the other of the two numbers Z1 and Z2 of magnets is equal to 2 M+[K-2] Y, where Y is a positive integer less than M. Then , first and second subsets of each M corresponding magnets are respectively placed in two series of M angular positions, these two series being offset from one another by an angular pitch (a) and each having the angular period between their angular positions. Finally, the remaining corresponding [K-2] Y magnets are distributed among the K-2 other series of M angular positions, presenting between them the angular period, so that each comprises Y magnets, these K-2 other series and the said two series being offset from each other by the angular pitch (a). In a specific variant corresponding to the three alternatives represented, the number M is an even number and the number Y is equal to M/2, the Y pole parts placed in each of the K-2 other series being distributed regularly by presenting between them distances angular equal to twice the angular period (2 β). An even more general variant can be defined in the same way with said other of the two numbers Z1 and Z2 which is provided equal to 2 W+[K-2] Y, where W is a positive integer greater than one and less than or equal to M, and where Y is a positive integer less than W. Then, two adjacent series of positions angular each include W magnets and the remaining magnets are distributed as shown above.

Claims (18)

Timepiece comprising a rotating bezel mounted on part of a casing of this timepiece and operable in rotation by a user, this rotating bezel having N given stable angular positions, N being an integer greater than two, which have between them an angular pitch (α) equal to 360° divided by N (α = 360°/N), the timepiece further comprising a magnetic device (6) composed of a first set of first pole parts carried fixedly by the rotating bezel and of a second set of second pole parts carried fixedly by said casing part, the first set of first pole parts and the second set of second pole parts each being arranged circularly so that the first pole parts have a magnetic interaction with the second pole parts which generates on the rotating bezel a resistive magnetic torque, on at least a part of said angular pitch, when this rotating bezel is driven in rotation, at least in a given direction, from any one of the N stable angular positions towards a following stable angular position; characterized in that the number Z1 of first pole parts in said first set is greater than one and less than N (1 < Z1 <N) and the number Z2 of second pole parts in said second set is also greater than one and less than N (1 < Z2 <N); and in that the first set of Z1 first pole parts is distributed among N first angular positions, linked to the rotating bezel and having said angular pitch between them, with at most one first pole part per first angular position, and the second set of Z2 second pole parts is distributed among N second angular positions, linked to said covering part and having between them said angular pitch, with at most one second pole part per second angular position, so that said resistive magnetic torque presents a variation as a function of the stable angular position of the rotating bezel, among the N stable angular positions, at least according to said given direction for the rotation of this rotating bezel. Timepiece according to Claim 1, characterized in that the first pole parts are magnetically similar and the second pole parts are magnetically similar; and in that the numbers Z1 and Z2 are selected and the distribution of the first set of Z1 first pole parts, among the N first angular positions, as well as the distribution of the second set of Z2 second pole parts, among the N second angular positions, are made so that said variation of the resistive magnetic torque is periodic. Timepiece according to Claim 2, characterized in that the periodic variation of the resistive magnetic torque has an angular period equal to an integer K of angular steps, this integer K being greater than one and selected so that the division of the whole number N by this number K is equal to a positive whole number M. Timepiece according to Claim 3, characterized in that the numbers Z1 and Z2 are selected and the said distribution of the first set of Z1 first pole parts as well as the distribution of the second set of Z2 second pole parts are carried out in such a way that the said variation of the resistive magnetic torque has, at least for said given direction of rotation of the rotating bezel, substantially two distinct non-zero values. Timepiece according to Claim 3 or 4, characterized in that one of the two numbers Z1 and Z2 is equal to M and the M corresponding pole parts (24) are distributed regularly, presenting between them said angular period (β), while the other of the two numbers Z1 and Z2 is equal to M+[K-1] Y, where Y is a positive integer less than M, and a subset of M corresponding pole parts (22) are placed in a first series (S0) of M angular positions having between them the angular period, the remaining corresponding [K-1] Y pole parts being distributed in K-1 other series of M angular positions , having between them the angular period, so that each comprises Y pole parts, these K-1 other series and the first series each being angularly offset from said angular pitch (a) relative to the two adjacent series. Timepiece according to Claim 5, characterized in that the number M is an even number and the number Y is equal to M/2, the Y pole parts placed in each of the said K-1 other series being distributed regularly, presenting between they have intervals equal to twice the angular period (2·β). Timepiece according to any one of Claims 4 to 6, characterized in that the said number N is equal to sixty (N=60) and the said number K is equal to five (K=5). Timepiece according to Claim 3 or 4, characterized in that the said number N is equal to sixty (N=60) and the said number K is equal to five (K=5); and in that one of the two numbers Z1 and Z2 is equal to 2·M, i.e. twenty-four, and the twenty-four corresponding pole parts (24) are arranged in a first series (S5) and a second series ( S6) of each of twelve angular positions having between them the angular period (β), these first and second series being shifted by the said angular pitch (α), while the other of the two numbers Z1 and Z2 is equal to or greater than 3 M , i.e. thirty-six, and three subsets of each twelve corresponding pole parts (22) are placed respectively in a third series (S0), a fourth series (S1) and a fifth series (S3) of each twelve angular positions having between them the angular period, the third and fourth series being shifted by said angular pitch (α) while the fifth series is offset by two angular steps (2 α) relative to each of these third and fourth series, a sixth series (S2) and a seventh series (S4), adjacent to the fifth series, each comprising the same number W of pole parts, this number W being less than the number M, i.e. less than twelve. Timepiece according to Claim 3 or 4, characterized in that the said number N is equal to sixty (N=60) and the said number K is equal to five (K=5); and in that one of the two numbers Z1 and Z2 is equal to 2-M, i.e. to twenty-four and the twenty-four corresponding pole parts are arranged in a first series and a second series of each twelve angular positions present between them the angular period (β), these first and second series being offset by two angular steps (2 α), while the other of the two numbers Z1 and Z2 is equal to or greater than 3-M, i.e. thirty-six, and three subsets of each twelve corresponding pole parts are respectively placed in a third series, a fourth series and a fifth series of each twelve angular positions having between them the angular period, these third, fourth and fifth series being offset from each other by said angular pitch (α), a sixth series and a seventh series adjacent and located between the fifth series and the third series each comprising the same number W of pole parts, this number W being less than the number M, less than twelve. Timepiece according to Claim 8 or 9, characterized in that the said number W is equal to zero. Timepiece according to any one of the preceding claims, characterized in that the first set of first pole parts and the second set of second pole parts are formed from materials generating a magnetic attraction between this first set and this second set; and in that the N stable angular positions of the rotating bezel are each defined by a positioning of first pole parts respectively opposite second pole parts. Timepiece according to Claim 11, characterized in that the first set of first pole parts and the second set of second pole parts are both formed of permanent magnets. Timepiece according to Claim 11, characterized in that one set among the first set of first pole parts and the second set of second pole parts is formed of permanent magnets, while the other set is formed of parts in ferromagnetic material. Timepiece according to Claim 3 or 4, characterized in that the first set of first pole parts and the second set of second pole parts are formed of permanent magnets generating magnetic repulsion between this first set and this second set; and in that the N stable angular positions are each defined by positioning the N first angular positions with an angular shift equal to substantially half of said angular pitch (α/2) relative to the N second angular positions. Timepiece according to Claim 14, characterized in that one of the two numbers Z1 and Z2 is equal to M and the M corresponding magnets are distributed regularly, presenting between them angular distances equal to said angular period (β), while the other of the two numbers Z1 and Z2 is equal to 2·M+[K-2]·Y, where Y is a positive integer less than M, and first and second subsets of each M corresponding magnets are placed respectively in two series of M angular positions, these two series being offset from each other by said angular pitch (a) and each having the angular period between their angular positions, the [K- 2] Y remaining corresponding magnets being distributed in K-2 other series of M angular positions, having between them the angular period, so that each comprises Y magnets, these K-2 other series and the said two series each being offset from each other of the angular pitch (α). Timepiece according to Claim 15, characterized in that the number M is an even number and the number Y is equal to M/2, the Y magnets placed in each of the said K-2 other series being distributed regularly, presenting between them angular distances equal to twice the angular period (2 β). Timepiece according to any one of Claims 14 to 16, characterized in that the said number N is equal to sixty (N=60) and the said number K is equal to five (K=5). Timepiece according to any one of the preceding claims, characterized in that the first set of first pole parts and the second set of second pole parts are respectively arranged in two concentric circles so that the radial magnetic force is generally substantially zero.

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