Patent Grant
11573532
This application claims priority to European Patent Application No. 19188844.5 filed on Jul. 29, 2019, the entire disclosure of which is hereby incorporated herein by reference.
The invention relates to a device for guiding pivotally for a pivoting mass.
The invention also relates to an horological resonator mechanism including at least two devices for guiding pivotally.
The invention also relates to an horological movement including such a resonator mechanism.
Flexible guides with a virtual pivot allow to substantially improve horological resonators. The simplest ones are cross-spring pivots, composed of two guide devices with straight leaves that intersect, in general perpendicularly. These two leaves can be either three-dimensional in two different planes, or two-dimensional in the same plane and are thus as if they were welded at their point of intersection.
It is possible to optimise a three-dimensional cross-spring pivot for an oscillator, to try to make it isochronous with a rate independent of its orientation in the field of gravity, in particular in two ways (independently, or the two together):
However, the use of such devices does not allow to achieve perfect deflection of the leaves. Indeed, obtaining a virtual axis sufficiently stable during the pivoting for the rotary movement of the mass to be perfectly periodic is not achieved. The return torque is not exactly linear, which causes an anisochronism according to the amplitude of the mass.
Moreover, the centre of mass of the mechanism moves too much, and also causes an anisochronism caused by its orientation with respect to gravity.
The invention seeks to avoid the aforementioned defects and aims to improve the behaviour of flexible pivots, in particular for their use in a resonator mechanism.
The invention thus relates to a device for guiding rotatably pivotally a pivoting mass about a virtual pivoting axis, the device comprising a first support and a second support, one of which is fixed and the other of which is intended to be rotary and to form or to support the pivoting mass, the device being substantially arranged in a plane and comprising a first and a second flexible leaf oriented in the same direction when the device is at rest, as well as an intermediate leaf having a rigidity notably greater than the flexible leaves and connecting the first flexible leaf to the second, the device comprising a first fixed link formed by the first support and a first end of the first leaf, a second fixed link formed by a second end of the first leaf and by a first end of the intermediate leaf, a third fixed link formed by a second end of the intermediate leaf and by a first end of the second leaf and a fourth fixed link formed by at least one second end of the second leaf.
The device is remarkable in that the first and/or the fourth link is arranged substantially between the second and the third link in said direction when the device is at rest.
Thus, the invention is a cross-spring pivot comprising an intermediate leaf having a rigidity greater than the flexible leaves and the first and/or the fourth fixed link of which is arranged between the second and the third fixed link. Such a pivot allows to keep a more stable centre of mass during the pivoting of the mass, in order for the flexibility and the return torque to be more linear. The problems of anisochronism caused by gravity are also greatly reduced, in particular in a resonator mechanism, so that the horological mechanical movements are more precise.
According to a specific embodiment of the invention, the fourth fixed link is arranged between the second end of the second leaf and the second support, which is rotary, the first support being fixed.
According to a specific embodiment of the invention, the fourth link is arranged between the second and the third link in said direction when the device is at rest.
According to a specific embodiment of the invention, the first and the fourth link are arranged between the second and the third link in said direction when the device is at rest.
According to a specific embodiment of the invention, the intermediate leaf is elbowed, preferably in the shape of a U.
According to a specific embodiment of the invention, the intermediate leaf is flexible with a cross-sectional inertia greater than that of the flexible leaves.
According to a specific embodiment of the invention, the intermediate leaf has a length x1 defined by the following equation:
where L1 is the length of the first flexible leaf and L2 is the length of the second flexible leaf.
According to a specific embodiment of the invention, the distance between the fourth link and the centre of mass of the pivoting mass is a length x2 defined by the following equation:
where L1 is the length of the first flexible leaf and L2 is the length of the second flexible leaf.
According to a specific embodiment of the invention, the length of the first leaf L1=L, and the intermediate leaf has a length x1 defined by the following equation: x1=36/25L.
According to a specific embodiment of the invention, the length L1 of the first leaf L1=L, and the distance between the fourth link and the centre of mass of the pivoting mass is a length x2 defined by the following equation: x2=3/5L.
According to a specific embodiment of the invention, the second flexible leaf has a length L2 defined by the following equation:
According to a specific embodiment of the invention, the device comprises a second intermediate leaf, the fourth link being formed by the second end of the second leaf and a first end of the second intermediate leaf, the first support being rotary.
According to a specific embodiment of the invention, the device comprises a third flexible leaf between the second intermediate leaf and the second fixed support, the device comprising a fifth fixed link formed by a second end of the second intermediate leaf and by a first end of the third leaf, as well as a sixth fixed link formed by at least one second end of the third leaf.
According to a specific embodiment of the invention, the sixth fixed link is formed by the second end of the third leaf and the second fixed support.
According to a specific embodiment of the invention, the fifth and the sixth link are arranged between the second and the third link in said direction when the device is at rest.
The invention also relates to an horological resonator mechanism including a pivoting mass arranged to pivot in a rotary manner about a virtual pivoting axis, the mechanism comprising two flexible devices for guiding rotatably pivotally according to the invention.
According to a specific embodiment of the invention, the directions of the flexible leaves of the respective devices are substantially perpendicular to one another when the mechanism is at rest.
According to a specific embodiment of the invention, the mechanism includes a third guide device, the three devices being superimposed.
According to a specific embodiment of the invention, the devices are distributed angularly, so that the directions of the flexible leaves of the three guide devices are arranged at 120° two by two.
According to a specific embodiment of the invention, the rotary supports of the devices are rigidly connected.
According to a specific embodiment of the invention, the fixed supports of the devices are rigidly connected.
According to a specific embodiment of the invention, the flexible leaves of each device have the same length two by two.
According to a specific embodiment of the invention, the devices are arranged on parallel planes.
The invention also relates to an horological movement including such an horological resonator mechanism.
Other features and advantages of the invention will appear upon reading the following detailed description, in reference to the appended drawings, in which:
The invention relates to a device 1 for guiding rotatably pivotally a pivoting mass about a virtual pivoting axis A, as shown in
The device 1 comprises a first 4 and a second flexible leaf 5 as well as an intermediate leaf 6 connecting the first flexible leaf 4 to the second 5. The first 4 and the second leaf 5 preferably have a similar, or even identical, cross-sectional inertia. The invention is illustrated in a preferred particular case in which the most flexible leaves are straight. Other geometries are nevertheless possible, for example in the shape of a coil, or others.
The intermediate leaf 6 has a rigidity notably greater than the flexible leaves 4, 5. In other words, the intermediate leaf 6 has a greater stiffness coefficient that the flexible leaves.
According to a first embodiment, the coefficient of the intermediate leaf 6 is much greater, so that the intermediate leaf 6 is considered to not be flexible under the effect of the pivoting mass.
According to a second embodiment, the intermediate leaf 6 is also flexible, but less than the first 4 and the second leaf 5. In this case, the difference in flexibility between the two types of leaves is still notable. Thus, the intermediate leaf 6 is flexible under the effect of the pivoting mass. For this purpose, the intermediate leaf 6 has, for example, a greater cross-section than the flexible leaves 4, 5 if they are made from the same material. Preferably, the first 4 and the second flexible leaf 5 have an identical cross-section.
The device 1 comprises four fixed links of the leaves 4, 5, 6:
The term fixed link means that the ends are durably fastened to one another, for example one end being rigidly set in the other.
In the rest position, the first leaf 4 is substantially perpendicular to the fixed support 2, and the second leaf 5 is substantially collinear to the first leaf 4, while the intermediate leaf 6 is substantially parallel to the first 4 and second 5 leaves. Thus, the four fixed links are aligned in the same direction of the flexible leaves 4, 5 in the rest position. In
According to the invention, the first 7 and/or the fourth fixed link 11 is arranged between the second 8 and the third fixed link 9, when the device 1 is at rest. In the embodiment of
For this purpose, the intermediate leaf 6 is elbowed, here in the shape of a straight U, to be able to partly surround the first 7 and the fourth fixed link 11. The base B of the U is the longest and has a length x1 defined by the following equation:
where L1 is the length of the first flexible leaf 4 and L2 is the length of the second flexible leaf 5. The lengths are vectors defined with respect to axes and an origin, not shown in the drawings. It is understood that the negative values are oriented in the reverse direction to the positive values. Thus, certain values can be negative, like L1 or L2, and consequently x1 or x2.
Moreover, the distance between the fourth fixed link 11 and the centre of mass of the pivoting mass is a length x2 formed by the back of the L and defined by the following equation:
Via these dimensions, the centre of mass of the system is more stable when the device pivots, since the centre of mass of the pivoting mass is immobile until the second order of the limited development of the position of the centre of mass with respect to the angle of deflection in the plane of the device 1.
In a preferred mode, a length L1=L of the first leaf 4 and a length
of the second flexible leaf 5 are chosen. Thus, the flexible leaves 4, 5 do not risk colliding during the pivoting. Having to dispose the leaves on two different levels to avoid impacts is avoided. Consequently, the length x1 of the intermediate leaf 6 is defined by the following equation: x1=−36/25L; and the rotary support 3 has a length x2 defined by the following equation: x2=3/5 L, which corresponds to the distance between the fourth fixed link 11 and the centre of mass of the pivoting mass.
In an advantageous embodiment, the first fixed support 11, the second fixed support 12, and the leaves form a one-piece assembly. This one-piece assembly can be made by technologies of the MEMS or LIGA type or similar, from silicon or similar, thermally compensated, in particular by a particular local growth of silicon dioxide, in certain zones of the part arranged for this purpose, when this one-piece assembly is made of silicon.
According to a third embodiment, not shown in the drawings, the device comprises a second intermediate leaf and a third flexible leaf, the rotary and fixed supports being inversed with respect to the previous embodiments. Thus, the first fixed link is formed by the rotary support and the first end of the first flexible leaf, the second fixed link is formed by the second end of the first flexible leaf and the first end of the first intermediate leaf, the third fixed link is formed by the second end of the first intermediate leaf and the first end of the second flexible leaf, while the fourth fixed link is formed by the second end of the second flexible leaf and by a first end of the second intermediate leaf. The device includes a fifth fixed link formed by a second end of the second intermediate leaf and a first end of the third flexible leaf, as well as a sixth fixed link formed by the second end of the third flexible leaf and the fixed support. In this embodiment, the first, fourth, fifth and sixth fixed links are for example arranged between the second and the third fixed link, when the device is at rest.
The two devices 12, 21 are arranged on two parallel planes to be able to pivot without collision of the leaves. In this example, the two devices 12, 21 are substantially perpendicular to one another. Thus, the directions of the flexible leaves 16, 17, 18, 19 of the respective devices 12, 21 are substantially perpendicular when the mechanism 10 is at rest.
In other embodiments, the devices can be oriented differently, by forming an angle different than 90° between them, for example 60°.
Moreover, the directions of the flexible leaves are straight. The intermediate leaves 31, 32 of the two devices 12, 21 are substantially perpendicular in the rest position, and intersect at a first point 35. Since the devices 12, 21 are on two different planes, the leaves do not collide during the operation of the mechanism 10. The first 16 and the third 18 flexible leaf are substantially perpendicular in the rest position, and intersect at a second point 36 defining the centre of mass of the rotary support and of the pivoting mass. The second point 36 also defines the position of the virtual axis around which the rotation of the mechanism occurs, in particular for the pivoting mass. The pivoting axis is substantially perpendicular to the planes of the devices.
The rotary supports 33, 34 of the two devices are rigidly connected to one another, just like the fixed supports 22, 23 of the two devices 12, 21. Here, the rotary supports 33, 34 have the shape of a straight leaf, which can be of the same nature as the intermediate leaves, preferably not flexible. The rotary supports 33, 34 are substantially perpendicular to the flexible leaves 16, 17, 18, 19 of the respective devices 12, 21. The rotary supports 33, 34 are fastened to one another by their opposite ends in order to form a corner 15 in the shape of a bracket. The corner 15 can form a support for an oscillating mass of the mechanism, a balance for example.
When the mechanism 10 is actuated, the two devices 12, 21 pivot, so that the corner 15 carries out a periodic balance movement about the virtual axis. The movement is produced via the flexible leaves which bend under the effect of the movement of the rotary supports with or without the mass.
The resonator mechanism 10 can include a plurality of such flexible devices for guiding pivotally 12, 21 mounted in series, to increase the total angular travel, disposed in parallel planes, and around the same virtual pivoting axis A.
In each of them, the first fixed link 47, 52 is arranged outside of the intermediate leaf 42, 45. Thus, the first flexible leaf 39, 43 is outside of the intermediate leaf 42, 45.
Thus, the mechanism is more compact than that of the first embodiment. The intermediate leaves 42, 45 have the shape of a deformed U, in which the branch linked to the first flexible leaf 39, 43 by the first fixed link 48, 53 is slightly convex and longer than the other, the base of the U being concave towards the inside of the U. The fixed supports are identical in the various alternatives, and together form a first arc of a circle 37 having an angle substantially equal to 90°. The first arc 37 includes a first attachment 46, here a ring arranged on the outer part of the arc 37 in the plane of the device, in order to be able to fasten the resonator mechanism to an horological movement.
In the alternatives of
The ring forming the second attachment 56 of
In
In the alternative of
Regardless of the alternative, when the mechanism 20, 30, 40 is actuated, the two devices pivot, so that the attachment carries out a periodic balance movement about the virtual axis. The movement is produced via the flexible leaves which bend under the effect of the movement of the rotary supports with or without the mass.
In this embodiment, the intermediate leaves 76, 77 further have a cellular structure in the thickness of the leaf. The cells are tubular over the entire height of the leaf to obtain “skeletal” leaves. Thus, the weight of the intermediate leaves 76, 77 is reduced while keeping sufficient rigidity.
Embodiments including only one of these two additional features are of course possible.
The flexible leaves 83, 84, 85, 86, 87, 88, the second intermediate leaves 92, 93, and the rotary and fixed supports of the two devices 81, 82 are arranged in the same plane. The first intermediate leaves 89, 91 are arranged in a second plane parallel to the first.
The rotary supports of the devices 81, 82 are rigidly connected and form an arc of a circle 94. The fixed supports of each device 81, 82 are also rigidly connected to one another in such a way as to form a corner 95 in the arc of a circle 94. The arc of a circle 94 can move with respect to the corner 95 when the mechanism is moving.
For each device 81, 82 in the rest position, the first, fourth, fifth and sixth fixed links are arranged between the second 96, 97 and the third fixed link 98, 99.
The axis of symmetry A passes substantially through the two flexible leaves 105, 106, 107 of each device 101, 102, 103 when the mechanism is at rest. The centre of mass of the pivoting mass is defined by the axis of symmetry, which is the point of intersection of the second flexible leaves 105, 106, 107. The guide devices 101, 102, 103 are of the type of those described for the second embodiment of the resonator mechanism of
Like for the devices of
The fixed supports 108 include third superimposed arcs 121, 122, 123 having various lengths according to the arrangement of the devices 101, 102, 103. The third arcs 121, 122, 123 are rigidly connected and extended towards the outside of the mechanism by a second attachment 125.
The second 114, 115, 116 and the third arcs of a circle 121, 122, 123 define a circular space inside of which the elements of the devices 101, 102, 103 are arranged, except for the attachments 120, 125. The first 120 and the second attachment 125 are, preferably, disposed symmetrically on either side of this space.
The invention also relates to an horological movement including a resonator mechanism such as one of those described above, for example for a balance of the horological movement.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19188844 | Jul 2019 | EP | regional |
| Number | Name | Date | Kind |
|---|---|---|---|
| 9477205 | Born | Oct 2016 | B2 |
| 10394190 | Lechot | Aug 2019 | B2 |
| 20130176829 | Cusin | Jul 2013 | A1 |
| 20170227930 | Di Domenico et al. | Aug 2017 | A1 |
| 20190064741 | Di Domenico et al. | Feb 2019 | A1 |
| 20190064742 | Di Domenico et al. | Feb 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 106662839 | May 2017 | CN |
| 107024852 | Aug 2017 | CN |
| 107065493 | Aug 2017 | CN |
| 3 206 089 | Aug 2017 | EP |
| 3 451 072 | Mar 2019 | EP |
| 2017-142246 | Aug 2017 | JP |
| 2019-45491 | Mar 2019 | JP |
| Entry |
|---|
| Combined Chinese Office Action and Search Report dated Aug. 17, 2021 in corresponding Chinese Patent Application No. 202010755490.1 (with English Translation of Category of Cited Documents), 6 pages. |
| European Search Report dated Jan. 17, 2020 in European Application 19188844.5 filed Jul. 29, 2019 (with Written Opinion and English Translation of Categories of Cited Documents), 7 pages. |
| Japanese Office Action dated Jul. 13, 2021 in Japanese Patent Application No. 2020-120370 (with English translation), 7 pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20210034016 A1 | Feb 2021 | US |
