CH706670A2 - Backlash clockwork wheel for use in clockwork gear train of movement of timepiece, has toothing comprising pairs of teeth, where each pair includes flexible teeth on either side of radial axis, and distances between teeth are different - Google Patents

Abstract

The wheel (10) has a first toothing (11) arranged according to a pitch circle (12) for meshing with a second toothing (21), where the second toothing has teeth (23) with given width (24) along a constant pitch (P2) on another pitch circle (22) of a counter mobile unit. The first toothing includes a succession of pairs (2) of mutually identical and consecutive teeth along a constant pitch (P1) on the pitch circle. Each pair has flexible teeth (4, 5) on either side of a radial axis (3). Distances (91, 92) between the successive flexible teeth measured on the pitch circles are different. An independent claim is also included for a clockwork gear train.

Description

Field of the invention

The invention relates to a time-compensating wheel for meshing with a second toothing consisting of second teeth of consecutive given width according to a second constant pitch on a second pitch diameter of an opposing mobile, said wheel comprising, arranged to mesh with said second toothing, a first toothing according to a first pitch circle and having a succession of pairs of teeth identical to one another and consecutive in a first constant pitch on said first pitch circle, each said pair comprising, on the one hand, and other a radial axis, a first flexible tooth and a second tooth.

The invention also relates to a watchwheel comprising at least one such watch wheel to catch play, and at least a second mobile having a said second toothing consisting of said second teeth of said consecutive given width according to the invention. a second constant step on a second primitive diameter.

The invention also relates to a watch movement comprising at least one such gear.

The invention also relates to a timepiece comprising at least one such movement, and / or at least one such gear.

The invention relates to the field of timepiece mechanism comprising gear transmission means.

Background of the invention

[0006] The search for gear meshing with minimal clearance, or with play catch-up, is a constant concern in watchmaking. The difficulty lies in the inevitable variations of center distance, due in particular to the functional games in the pivots. These variations of center distance can be compensated by flexible teeth, however their design is difficult, because of their energy consumption, and therefore their impact on the overall performance of the gear. An example is given by the document EP 2003 522 in the name of Chopard Manufacture SA, which describes a reciprocating toothed wheel with an alternation of rigid teeth and flexible teeth, this mobile cooperating with a rigid teeth drive wheel, the rigid drive tooth being gripped between the rigid tooth and the elastic tooth of the driven wheel, so as to catch the gear set by the permanent contact between the rigid tooth of the driving wheel and the meshing side of the driven wheel.

Such a geometry is preferably designed for a direction of rotation, and lends itself imperfectly to a change of direction of meshing. In addition, the known flexible wheels are, in use, very sensitive to wear.

It is therefore both to make up the game, and to avoid any problem of display during a change of direction, for example during a time setting.

Summary of the invention

The invention proposes to define a gear whose meshing is without play, whatever the direction of rotation, with minimal torque consumption, and with the least possible wear in service.

For this purpose, the invention relates to a time-of-play wheel for meshing with a second toothing consisting of second teeth of consecutive given width according to a second constant pitch on a second pitch diameter of one mobile wheel, said wheel comprising, arranged to mesh with said second toothing, a first toothing according to a first pitch circle and comprising a succession of pairs of teeth identical to one another and consecutive in a first constant pitch on said first pitch circle, each said pair having, on either side of a radial axis, a first flexible tooth and a second tooth, characterized in that each said second tooth is a flexible tooth, and in that the distances measured on said first pitch circle between a said first tooth and a second said second tooth are different two by two.

According to one characteristic of the invention, in the free state, a first distance, measured on said first pitch circle between said first tooth and said second tooth of the same pair, is the smallest distance between two said successive flexible teeth, and is substantially less than said given width, measured on said second pitch circle, said second teeth constituting said second toothing.

According to another characteristic of the invention, in the free state, a second distance, measured on said first pitch circle between a said first tooth and a second said adjacent tooth but belonging to said different pairs, is the distance the largest between said two successive flexible teeth and is substantially less than the sum of, on the one hand, said second pitch of said second toothing, and on the other hand said given width, measured on said second pitch circle, of said second teeth constituting said second toothing.

According to another feature of the invention, each said first tooth and each said second tooth each comprise, on either side of a radial axis, two lateral abutment surfaces facing respectively to said two adjacent second teeth. and to the two said first adjacent teeth, and, in the free state, the third distance between two said lateral abutment surfaces facing each other of said two consecutive teeth is constant.

The invention also relates to a watchwheel comprising at least one such first game-making clock wheel, and at least one second mobile having a said second toothing consisting of said second teeth of said consecutive given width according to the invention. a second constant pitch on a second pitch diameter, characterized in that, in any meshing position of said first wheel and said second moving wheel, at least one said second tooth is pinched by a said first tooth and a said second tooth of one and the same pair spaced from each other, in the free state, of said first distance.

The invention also relates to a watch movement comprising at least one such wheel, characterized in that said second wheel is driving, and said first wheel is driven, and in that said at least one wheel is reversible and has identically in both directions of pivoting.

The invention also relates to a timepiece comprising at least one such movement, and / or at least one such gear, characterized in that said at least one gear is reversible and behaves identically in both directions pivoting.

Brief description of the drawings

Other features and advantages of the invention will appear on reading the detailed description which follows, with reference to the accompanying drawings, in which: fig. 1 represents, in a schematic and plan view, a part of a train according to the invention, comprising a first game-catching wheel according to the invention with a succession of pairs of identical teeth, these pairs being equidistant, and each pair comprising a first flexibie tooth and a second tooth according to the invention, in a first meshing position; fig. 2 represents the mechanism of FIG. After a slight angle of rotation of the two wheels; figs. 3 to 7 show a pivoting sequence of the train of FIG. 1, from a first reference position 0 ° of the first wheel 10, through pivoting positions every 6 ° of the wheel 10: 6 ° in FIG. 4, 12 ° in fig. 5, 18 ° in fig. 6, 24 ° in fig. 7; fig. 8 shows, in a similar way, another variant of the invention, with other forms of teeth; fig. 9 shows, in the form of a block diagram, a timepiece comprising a movement including such a train according to the invention.

Detailed Description of the Preferred Embodiments

The invention relates to the field of timepiece mechanism comprising gear transmission means.

The invention proposes to define a gear whose meshing is without play, whatever the direction of rotation, with minimal torque consumption, and with the least possible wear in service.

The principle of the invention is to use, for one of the wheels of the train, hereinafter referred to as a clearance wheel 10, a particular toothing, whose pitch varies between two successive teeth: once smaller only theoretically, for meshing with a given opposing motive, and once larger, the total of the smallest step and the largest step being equal to twice the theoretical pitch. The smallest step is weaker than the width of a tooth, at the level of the primitive diameter, of the opposing motive, the greatest step is greater than this same width.

Each tooth is preferably placed on a flexible arm, attached to a hub of the wheel.

This configuration allows the two teeth whose pitch is the smallest to pinch an opposite tooth of an opposing mobile, and thus removes the games.

In the next step, during the passage on the widest pitch, the pinching is done on the opposite outer teeth, as will be detailed below.

Thus, the invention relates to a watch wheel 10 with play clearance. This first wheel 10 is arranged to mesh with a second toothing 21 consisting of second teeth 23 of given width 24 consecutive in a second pitch P2 constant on a second pitch diameter 22 of an opposing mobile.

The wheel 10 comprises arranged to mesh with such a second toothing 21, a first gear 11 according to a first pitch circle 12. This first toothing 11 comprises a succession of pairs 2 of teeth. These pairs 2 are identical to each other, and consecutive in a first pitch P1 constant on the first pitch circle 12. Each such pair 2 comprises, on either side of a radial axis 3 which separates them, a first flexible tooth 4 and a second tooth 5.

In a preferred embodiment, for indifferent use in one or the other direction of rotation, each pair 2 is symmetrical with respect to its radial axis 3, and the first tooth 4 is the mirror of the second tooth 5.

According to the invention, each second tooth 5 is a flexible tooth, and the distances 91, 92, measured on the first pitch circle 12 between a first tooth 4 and a second tooth 5 successive are different two by two.

As visible in FIGS. 1 and 2, in the free state, a first distance 91, measured on the first pitch circle 12 between the first tooth 4 and the second tooth 5 of the same pair 2, is the smallest distance between two flexible teeth 4 and 5 successive, and is substantially smaller than the given width 24, measured on the second pitch circle 22, second teeth 23 constituting the second toothing 21.

In the same way, in the free state, a second distance 92, measured on the first pitch circle 12 between a first tooth 4 and a second tooth 5 adjacent but belonging to pairs 2 different and consecutive, is the distance the largest between two flexible teeth 4 and 5 successive, and is substantially less than the sum of, firstly the second pitch P2 of the second toothing 21, and secondly the given width 24, measured on the second circle primitive 22, second teeth 23 constituting this second toothing 21.

It is understood that the pitch P1 between two consecutive pairs 2 is equal to the sum of the first distance 91, the second distance 92, and the widths 94 and 95 of the teeth 4 and 5 on the pitch diameter 12.

Preferably, each first tooth 4 and each second tooth 5 each comprise, on either side of a radial axis, respectively 41, 51, two lateral abutment surfaces 6 facing respectively to the two adjacent second teeth 5 and to the first two adjacent teeth 4.

In the free state, the third distance P3 between two such lateral abutment surfaces 6 facing two teeth 4, 5, consecutive is constant.

These abutment surfaces 6 have the function of limiting the effect of excessive torque applied by the driving wheel, in this case a second mobile 20 carrying the second toothing 21 in the case of a gear 100 such as illustrated by the figures, on the first wheel 10 according to the invention. In a particular, non-limiting embodiment, the clearance in the free state between two adjacent abutment surfaces 6 is close to 0.04 mm.

FIG. 2 shows these abutment surfaces, respectively 61 and 62 on the first tooth 4, on either side of its radial axis 41, and 63 and 64 on the second tooth 5, on either side of its radial axis 51 In the event of impact, the surfaces 62 and 63 of the same pair 2 bear against one another, and the adjacent surface 64 of a pair 2 with the surface 61 of the pair 2 directly adjacent.

FIG. 8 illustrates another variant of the invention wherein the first tooth 4 and second tooth 5 are not rigid, but flexible, in particular constituted by an elastic loop 65, which improves shock absorption.

In a particular version, illustrated by FIGS. 1 to 7, each first tooth 4 comprises a head 42, preferably rigid, attached to an axial hub 13 of the wheel 10 by a first flexible arm 43. Similarly, each second tooth 5 comprises a head 52, preferably rigid, attached to an axial hub 13 of the wheel 10 by a second arm 53 flexible. The choice of a long length for each flexible arm 43, 53, makes it possible to more easily manage the very low forces in the presence of a beam made in a tooth itself. Thus, preferably, the first teeth 4 and second teeth 5 are cantilevered with respect to an axial hub 13 with a radial output of between 0.50 and 0.95 times the value of the maximum radius of the wheel 10 .

The weak force allows the use of the wheel 10 in functions with low torque and high rotation speed, without disturbance or wear.

Advantageously, for its good reverse operation, the wheel 10 is symmetrical with respect to a plane passing through its pivot axis D1 and a radial axis 3 of a pair 2 that it comprises.

Figs. 3 to 7 show a pivoting sequence of the train of FIG. 1, from a first reference position 0 ° of the first wheel 10, through pivoting positions every 6 ° of the wheel 10: 6 ° in FIG. 4, 12 ° in fig. 5, 18 ° in fig. 6, 24 ° in fig. 7. The positions of the various teeth in the free state are shown in fine lines, and the deformed positions under the effect of applied forces are in broken line. In this example a second mobile 20, having the second toothing 21, is driving, and pivots in a counter-clockwise direction.

In the 0 ° position in FIG. 3, a tooth 23A of the second mobile 20 bears, by a lower lateral surface 81, on an upper lateral surface 72 of the first tooth 4X of the first wheel 10, and bears on this tooth 4X and tends to rotate the first wheel 10 The tooth 23A is pinched by the teeth 4X and 5X. The second upper lateral surface 82 of the tooth 23A is in contact with the second tooth 5X, and deforms it tending to push it in the opposite direction to that in which the surface 81 bears on the tooth 4X. the elastic restoring torque of tooth 5X tends to cause it to press on tooth 23A, and to accompany its thrust force on tooth 4X in order to turn wheel 10.

In the 6 ° position in FIG. 4, the tooth 23A is still in pinch contact with the teeth 4X and 5X, the next tooth 23B is free. The tooth 23C begins to bear, by its lower surface 85, on the upper surface 76 of the tooth 4Z, tending to rotate the wheel 10.

In the 12 ° position in FIG. 5, the tooth 23A is still in contact with the tooth 4X, but without exerting support on it. The tooth 23A is still resting on the lower surface 73 of the tooth 5X. The next tooth 23B is free. The tooth 23C presses, by its lower surface 85, on the upper surface 76 of the tooth 4Z, to rotate the wheel 10.

In the 18 ° position in FIG. 6, the tooth 23A is no longer in contact with the tooth 4X, and is still resting on the lower surface 73 of the tooth 5X. The next tooth 23B is free. The tooth 23c is pinched by the teeth 4Z and 5Z The tooth 23C presses, by its lower surface 85, on the upper surface 76 of the tooth 4Z, to rotate the wheel 10. The second upper lateral surface 86 of the tooth 23C is in contact with the second tooth 5Z, and the deformation tending to repel in the opposite direction to that in which the surface 85 rests on the tooth 4Z. the elastic return torque of the tooth 5Z tends to make it press the tooth 23C, and to accompany its thrust force on the tooth 4Z to rotate the wheel 10.

In the 24 ° position in FIG. 7, the teeth 23A and 23B are released. Only the tooth 23C is still pinched similarly to the position of FIG. 6.

The invention also relates to a watch train 100 comprising at least one such first wheel 10, and at least one second mobile 20 having such a second toothing 21 consisting of second teeth 23 of given width 24 consecutive according to a second step Constant P2 on a pitch diameter 22.

According to the invention, in any meshing position of the first wheel 10 and the second wheel 20, at least one second tooth 23 is gripped by a first tooth 4 and a second tooth 5 of the same pair 2 remote one from the other, in the free state, from the first distance 91.

In a preferred variant and illustrated in FIGS. 3 to 7, according to the angular meshing positions between the first wheel 10 and the second mobile 20, or a single second tooth 23 is pinched by a pair 2, as visible in FIGS. 3, 4, 6, and 7, or two second teeth 23 separated by a third second tooth 23 are gripped by two pairs 2 successive, as shown in FIG. 5.

In a particular variant, illustrated in FIGS. 3 to 7, on a complete revolution of the second mobile 20, only one in two of the second teeth 23 is, alternately, in driving contact with one of the teeth 4, 5, of the first toothing 11 of the first wheel 10. Thus, one tooth out of two of the second mobile 20 is clamped by the flexible teeth, which eliminates the clearance. It is possible, in a particular variant, not illustrated, to eliminate, when the number of teeth 23 of the second toothing 21 of the second mobile 20 is even, one tooth out of two. However, the embodiment with a continuous toothing, as illustrated by the figures, is less expensive and remains compatible with the existing wheels, it offers a better ease of assembly, since one can angularly position the second mobile 20 in a position any relative to the first wheel 10, when the number of teeth of the second mobile 20 is odd, all the teeth are solicited on two revolutions, this configuration is therefore a favorable factor in terms of wear reduction.

Preferably, the second toothing 21 of the second mobile 20 is second teeth 23 rigid.

Preferably, for the reverse operation, the second toothing 21 has teeth 23 each symmetrical with respect to a radial axis 25 passing through the pivot axis D2 of the second mobile 20, and said second mobile 20 is symmetrical relative to to a plane passing through its pivot axis D2 and by a radial axis 25 of a second tooth 23 that includes the second toothing 21.

The invention also relates to a watch movement 200 comprising at least one such gear train 100. Preferably the second mobile 20 is driving, and the first wheel 10 is driven, and this at least one wheel 100 is reversible and is has identically in both directions of pivoting.

The invention also relates to a timepiece 300 comprising at least one such movement 200, and / or at least one such gear 100.Deferentially this at least one gear 100 is reversible and behaves identically in its two pivoting directions.

The invention involves low pressure forces on the teeth to cancel the set of gear.

The invention allows very low meshing torques, for example for second rotation or meshing second chronograph applications.

Compared to the known mechanisms, the invention reduces the torque variations due to friction, and reduces the wear due to friction. The manufacture is facilitated, the play-back wheel according to the invention is easy to manufacture in micro-machinable material, silicon, or NiP or the like, by a "LIGA" method or the like. The assembly is easy and without risk of error.

The embodiment according to the invention allows, again, the distribution of stresses on several teeth during significant interference couples.

The invention thus achieves meshing objectives without play in both directions of operation, and low torque consumption, which makes it usable on second displays of small or flat motion, and low wear of toothings. Any needle flutter is eliminated, especially when used with a large central second needle at high unbalance.

Claims (15)

1. Watch wheel (10) for backlash, for meshing with a second toothing (21) consisting of second teeth (23) of given width (24) consecutive in a second step (P2) constant on a second primitive diameter (22) of an opposing mobile, said wheel (10) comprising, arranged to mesh with said second toothing (21), a first toothing (11) according to a first pitch circle (12) and comprising a succession of pairs ( 2) of teeth identical to one another and consecutive in a first step (P1) constant on said first pitch circle (12), each said pair (2) having, on both sides of a radial axis (3), a first flexible tooth (4) and a second tooth (5), characterized in that each said second tooth (5) is a flexible tooth, and in that the distances (91; 92) measured on said first primitive circle (12) between a said first tooth (4) and a said second tooth (5) successive are different two to two x. 2. Wheel (10) according to the preceding claim, characterized in that, in the free state, a first distance (91), measured on said first pitch circle (12) between said first tooth (4) and said second tooth ( 5) of the same pair (2), is the smallest distance between two said flexible teeth (4; 5) successive, and is substantially less than said given width (24), measured on said second pitch circle (22). ), said second teeth (23) constituting said second toothing (21). 3. Wheel (10) according to claim 1 or 2, characterized in that, in the free state, a second distance (92), measured on said first pitch circle (12) between a said first tooth (4) and a said second tooth (5) adjacent but belonging to said pairs (2) different, is the largest distance between two said flexible teeth (4; 5) successive and is substantially less than the sum of, on the one hand said second not (P2) of said second toothing (21), and secondly said given width (24), measured on said second pitch circle (22), said second teeth (23) constituting said second toothing (21). 4. Wheel (10) according to one of the preceding claims, characterized in that each said first tooth (4) and each said second tooth (5) each comprise, on either side of a radial axis (41; 51), two lateral abutment surfaces (6) facing respectively to said two adjacent second teeth and to both said first adjacent teeth (4), and in that, in the free state, the third distance (P3) between two said lateral abutment surfaces facing each other of said two consecutive teeth (4; 5) is constant. 5. Wheel (10) according to one of the preceding claims, characterized in that each said first tooth (4) comprises a rigid head (42) attached to an axial hub (13) of said wheel (10) by a first arm (43) flexible. 6. Wheel (10) according to one of the preceding claims, characterized in that each said second tooth (5) comprises a rigid head (52) attached to an axial hub (13) of said wheel (10) by a second arm (53) flexible. 7. Wheel (10) according to one of the preceding claims, characterized in that said first teeth (4) and second teeth (5) are cantilevered with respect to an axial hub (13) with a radial outlet between 0.50 and 0.95 times the value of the maximum radius of said wheel (10). 8. Wheel (10) according to one of the preceding claims, characterized in that it is symmetrical with respect to a plane passing through its pivot axis (D1) and a said radial axis (3) of a said pair (2) it involves. 9. Clockwork (100) comprising at least a first wheel (10) according to one of the preceding claims, and at least one second mobile (20) having a said second toothing (21) consisting of said second teeth (23). ) of said given width (24) consecutive in a second step (P2) constant on a pitch diameter (22), characterized in that in any meshing position of said first wheel (10) and said second mobile (20) at least one said second tooth (23) is pinched by a said first tooth (4) and a said second tooth (5) of the same pair (2) remote from each other, in the state free, of said first distance (91). 10. Gear (100) according to the preceding claim, characterized in that, according to the angular meshing positions between said first wheel (10) and said second wheel (20), or a single said second tooth (23) is pinched by a single said pair (2), or two said second teeth (23) separated by a third said second tooth (23) are pinched by two said pairs (2) successive. 11. Gear (100) according to claim 9 or 10, characterized in that, on a complete revolution of said second mobile (20), only one of two said second teeth (23) is in driving contact with one of said teeth (4; 5) of said first toothing (11) of said first wheel (10). 12. Gear (100) according to one of claims 9 to 11, characterized in that said second toothing (21) of said second mobile (20) is second teeth (23) rigid. 13. Gear (100) according to one of claims 9 to 12, characterized in that said second toothing (21) comprises said second teeth (23) each symmetrical with respect to a radial axis (25) passing through the axis pivoting (D2) of said second moving member (20), and in that said second moving member (20) is symmetrical with respect to a plane passing through said pivot axis (D2) and a said radial axis (25) of a said second tooth (23) that comprises said second toothing (21). 14. A watch movement (200) comprising at least one wheel (100) according to one of claims 9 to 13, characterized in that said second mobile (20) is driving, and said first wheel (10) is driven, and in that said at least one gear train (100) is reversible and behaves identically in both its pivoting directions. 15. Timepiece (300) comprising at least one said movement (200) according to the preceding claim, and / or at least one wheel (100) according to one of claims 9 to 13, characterized in that said at least a gear train (100) is reversible and behaves identically in both its pivoting directions.