CH713946A2 - Shock absorbing bearing for an axis of a mobile of a timepiece. - Google Patents

Abstract

The invention relates to a shock absorbing bearing for an axis of a mobile of a timepiece, in particular for a balance shaft. The bearing comprises a bearing block comprising a housing, a bearing support (20) arranged in the housing and comprising an outer centering wall (23b), a pivot bearing mounted on the bearing support (20) for receiving a pivot the axis of a mobile and an elastic support arrangement of the pivot of the axis of the mobile. The shock absorbing bearing further comprises a game refocusing device (40). This game centering mechanism comprises, on the one hand, a first part comprising a centering element (42) having an inner centering wall in which is arranged the outer centering wall (23b) of the bearing support (20) and on the other hand, a second part bearing on the bearing block and arranged so as to exert a return effect vis-à-vis the first part.

Description

Description

FIELD OF THE INVENTION [0001] The present invention relates to a shock absorbing bearing for an axis of a moving part of a timepiece, in particular for a balance shaft, and comprising a game refocusing device.

BACKGROUND OF THE INVENTION [0002] In watchmaking, the pivots of the axes of the mobiles rotate in bearings mounted in the plate or in bridges. For some mobiles, in particular the balance, it is customary to equip the bearings with a shock-absorbing mechanism. Indeed, as the pivots of the axis of a beam are generally thin and the weight of the balance is relatively high, the pivots can break under the effect of a shock in the absence of damper mechanism.

The configuration of a conventional shock absorber 1 is shown in FIG. 1a. An olive domed stone 2 is driven into a bearing support 3 commonly called kitten, on which is mounted a counter pivot stone 4. The kitten 3 is held in abutment against the bottom of a bearing block 5 by a damping spring 6 arranged to exert an axial stress on the upper part of the counter-pivot stone 4. The kitten 3 further comprises a conical outer wall arranged in correspondence with a conical inner wall disposed at the periphery of the bottom of the bearing block 5. There exists also variants according to which the kitten has an outer wall having a convex shape surface, that is to say curved.

For proper operation, the kitten 3 must be centered on the axis of the damping bearing and flat which is not easy to guarantee due to the tolerance intervals of the components.

In the first configuration, as illustrated in FIG. 1b, the centering position of the kitten 3 on the axis of rotation of the bearing has the disadvantage of being indefinite while in the second configuration, as shown in FIG. 1c, the kitten 3 can pivot about an axis perpendicular to the axis of the damping bearing, which has the adverse effect of positioning the kitten 3 at an angle and the pivot and the pivot against the pivot mounted on the kitten. SUMMARY OF THE INVENTION [0006] An object of the invention is therefore to provide a shock absorbing bearing for an axis of a mobile of a timepiece, in particular for an axis of a balance wheel, whose Tolerance intervals of the damping bearing components do not lead to the two undesired situations mentioned above.

For this purpose, the invention relates to a shock absorbing bearing for an axis of a mobile of a timepiece, in particular for a balance shaft. The bearing comprises a bearing block comprising a housing, a bearing support arranged in the housing and comprising an outer centering wall, a pivot bearing mounted on the bearing support for receiving a pivot of the axis of a mobile and an elastic support arrangement of the pivot of the axis of the mobile. The shock absorbing bearing further comprises a game refocusing device. This game refocusing device comprises, on the one hand, a first part comprising a centering element having an inner centering wall in which the outer wall of the center is arranged. centering of the bearing support and, secondly, a second portion bearing on the bearing block and arranged to exert a return effect vis-à-vis the first part.

This return effect allows the centering element of the game refocusing device to fit against the bearing support independently of manufacturing variations and to ensure a centering and a flat support of the bearing support against the bottom of the bearing block.

According to an advantageous embodiment, the outer centering wall of the bearing support and the inner centering wall of the centering element are each a conical wall. The taper of the inner centering wall of the centering element corresponds to the taper of the outer centering wall of the bearing support.

According to another embodiment, the outer centering wall of the bearing support is convex and the inner centering wall of the centering element is conical.

According to another embodiment, the outer centering wall of the bearing support is conical and the inner centering wall of the centering element is convex.

According to an advantageous embodiment, the bearing block comprises an inner wall comprising a cylindrical shoulder having a radial bearing surface and an axial bearing surface. The second part of the game refocusing device comprises an annular portion arranged on the radial bearing surface of the shoulder and an elastic portion extending beyond the radial bearing surface in the direction of the bearing axis. .

According to an advantageous embodiment, the elastic portion comprises a plurality of flexible blades arranged along a circular path for example. The flexible blades are configured to flex substantially axially under the effect of a shock as well as to compensate axial clearances and ensure the centering of the bearing support.

According to an advantageous embodiment, the centering element comprises an outer wall comprising a plurality of reinforcing and centering blocks, said blocks limiting the radial displacement of the bearing support and allowing, with the rest of the centering element. , to compensate for axial clearances and to ensure the centering of the bearing support. One and the other of the ends of each flexible blade are respectively connected to a corresponding block and to the annular portion of the second part of the game refocusing device.

According to an advantageous embodiment, each reinforcing block comprises a bearing surface arranged against the axial bearing surface of the shoulder for performing the centering of the bearing support. Each flexible blade comprises an outer side wall set back from the bearing surface of each block.

According to an advantageous embodiment, the axis of curvature of the flexible blades of the resilient portion corresponds to the axis of the bearing.

According to an advantageous embodiment, the annular portion of the second part of the game refocusing device has a square or rectangular cross section. The annular portion is preloaded (by driving, for example) in order to exert a force against a corner formed by the radial bearing surface of the shoulder and an axial bearing surface of the inner wall of the bearing block.

According to an advantageous embodiment, the bearing block comprises a base comprising an opening for the passage of the pivot axis of a mobile. The bearing support bears against the base of the bearing block. The centering element of the first part of the game refocusing device is remote from the base when the damping bearing is in a rest configuration, that is to say when the bearing is under the influence of no external constraint.

According to an advantageous embodiment, the game refocusing device is in a monolithic form.

BRIEF DESCRIPTION OF THE DRAWINGS [0020] Other features and advantages of the present invention will appear on reading several embodiments given solely by way of nonlimiting examples and with reference to the appended drawings in which: FIG. 1a represents an axial section of a damping bearing according to the state of the art; figs. 1b and 1c show a view similar to FIG. 1a, in which the kitten is respectively in a first and second position; fig. 2 shows an axial section of a damping bearing according to one embodiment of the invention; fig. 3 shows a truncated partial view of a cross section of the damping bearing of FIG. 2; fig. 4 is a perspective view from above of the game refocusing device of FIG. 2; fig. 5 is a perspective view from below of FIG. 4; and FIG. 6 shows an axial section of the damping bearing according to another embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0021] A shock absorbing bearing for an axis of a mobile, in particular for a balance shaft, of a timepiece will now be described according to one embodiment with reference to in figs. 2-5.

With particular reference to FIGS. 2 and 3, the shock absorbing bearing 10 comprises a bearing block 11 (hereinafter: bearing block), a bearing support 20, an elastic member 30 and a game refocusing device 40. bearing block 11 is shaped to be inserted into one or more orifices present on the plate or on one or more bridges of a clockwork movement (not shown). When the shock absorbing bearing 10 is used for example for a rocker, the racket and the stud holder are arranged around the bearing block 11. This bearing block 11 comprises a base 12 having an opening 13, preferably cylindrical, for the passage of a pivot of the axis of the balance.

The bearing block 11 further comprises an inner side wall defining a housing for receiving the bearing support 20 more commonly called kitten. The inner side wall comprises a main cylindrical wall 14a and a first and second complementary cylindrical walls 14b, 14c arranged on either side of the main cylindrical wall 14a, said lower cylindrical walls 14b and 14c upper.

The diameter of each of the lower and upper cylindrical walls 14b, 14c is smaller than the diameter of the main wall 14a of the inner side wall of the bearing block 11. The bottom wall 14b thus forms with the main wall 14a a cylindrical shoulder 16. The shoulder 16, meanwhile, forms with the main wall 14a a corner having an axial bearing surface 15a and a radial bearing surface 16a extending over 360 ° and centered on the axis of the damping bearing 10. The upper cylindrical wall 14c forms with the main wall 14a a radial bearing surface 15b arranged substantially facing the radial bearing surface 16a of the shoulder 16. In the variant shown, the upper wall 14c forms a rim allowing the attachment of the elastic member 30. It is obvious that other means can be implemented to fix the elastic member 30 so that the rim formed by the pa upper king 14c can be removed, the upper part of the main wall 14a being then right.

The kitten 20 has an inner side wall comprising a main cylindrical wall 21a and a complementary cylindrical wall 21b. A pivot bearing 24, in the form of a pierced stone of the domed stone with olive-hole type, is mounted inside the main cylindrical wall to maintain the axis of the balance in axial alignment. The pierced stone 24 is preferably hung but can also be glued or otherwise affixed to the main cylindrical wall of the inner kitten wall.

The diameter of the main cylindrical wall 21a of the kitten 20 is smaller than the diameter of the complementary cylindrical wall 21b so as to form a corner extending over 360 °.

The resilient support arrangement comprises a counter-pivot 25 mounted on the bearing support 20 and an elastic member 30 arranged to exert an axial force on the bearing support 20. The counter-pivot 25 is of cylindrical shape and is mounted above the pierced stone 24. More particularly, the peripheral portion of the counter-pivot 25 is held against a radial bearing surface 22a and axial 22b of the corner of the kitten 20 under the action of the organ elastic member 30 which is mounted inside the housing of the bearing block 11. The elastic member 30 may have the known shape of a lyre and has a lower side 31 whose central portion 31 has bears against the upper part counter-pivot 25 and an upper side 32 whose peripheral portion 32a is in abutment against the radial bearing surface 15b of the bearing block 11. The elastic member 30 is in a prestressing configuration in order to exert an axial force e optimal against the pivot against 25 when the damping bearing 10 is in a so-called rest configuration in which it is not subjected to any external stress. It will be appreciated that this resilient member may take a variety of forms and may be coupled to the bearing block 11 by other means. For example, the resilient member may have a shape partially covering the counter-pivot 25.

With reference to FIGS. 2 to 5, the game centering device 40 comprises a first part comprising a centering element 42 bearing against the kitten 20 and a second part comprising a peripheral zone bearing on the block of the bearing block 11 as will be described hereinafter. after that the second part exerts a return effect vis-à-vis the first part. More particularly, the centering element 42 comprises an inner wall comprising a conical wall 43a and a cylindrical complementary wall 43b and an outer wall 44 of cylindrical shape.

According to FIG. 5, a plurality of reinforcing blocks 45 are arranged on the outer wall 44. In this embodiment, four blocks 45 are preferably arranged at 90 ° to each other. Note, however, that an execution with a different number of blocks can be envisaged, for example three blocks arranged preferably at 120 ° relative to each other. Each block 45 has a bearing surface 45a arranged to bear against the axial bearing surface 16b of the shoulder 16 of the bearing block 11.

The second part of the game refocusing device 40 comprises an annular portion 46 resting integrally on the radial bearing surface 16a of the shoulder 16 of the bearing block 11 and a second elastic portion extending beyond the radial bearing surface 16a towards the axis of the bearing 10 and connected to the centering element 42. The annular portion 46 is of substantially constant cross section and for example of square shape (Figure 2). The annular portion 46 is prestressed to exert a force against the corner formed by the radial bearing surface 16a of the shoulder 16 and the axial bearing surface 15a of the main cylindrical wall 14a of the bearing block 11 to ensure the coupling of the recentering element 42 with the bearing block 11. Of course, other forms of coupling can be implemented.

The elastic portion of the second portion comprises a plurality of flexible blades 47 arranged along a path, for example circular, concentric with the centering element 42. These blades 47 are connected to the reinforcing blocks 45 and are configured to flex essentially axially under the effect of a shock as well as to compensate axial clearances related in particular to manufacturing variations and to ensure the centering and flattening of the kitten 20 at the bottom of the bearing block 11.

According to FIG. 4, the elastic portion preferably comprises four flexible blades 47 which each extend along an arc of a circle comprised between 60 ° and 85 ° but a different number of blades may be envisaged, for example three blades each extending along an arc of a circle between 90 ° and 115 °.

As can be seen in FIG. 5, the outer lateral wall 47a of each blade 47 is slightly set back from the bearing surface 45a of each block 45. This makes it possible to prevent the flexible blades 47 "rubbing" against the axial surface 16b of the shoulder 16 of the bearing block 11 when these blades flex axially so as to absorb the stresses caused by a substantially axial shock thus avoiding premature wear of the blades.

The ratio between the axial height of the centering element 42 and the axial height of the annular portion 46 is greater than two according to the embodiment illustrated in FIG. 2 while this ratio may be approximately equal to one according to an embodiment illustrated in FIG. 6. Note that according to this last embodiment, the outer side wall 47a of each blade 47 does not need to be set back from the bearing surface 45a of each block 45. Indeed, only the lower part of the bearing surface 45a of each block 45 is arranged against the axial bearing surface 16b of the shoulder 16 so that the blades can flex radially above the radial bearing surface 16a of the shoulder 16 through a clearance located between the inner side wall of the annular portion 46 and the outer side wall 47a of the flexible blades 47.

It should be noted that the dimensions of the flexible blades 47 and the material of the game refocusing device 40 must be carefully selected taking into account several considerations. For example, the blades must be able to bend axially sufficiently especially for the establishment of the elastic member 30 and not to lead to oversizing of this elastic member. On the other hand, the blades 47 must also not be too flexible so as to ensure a good (re) centering of the kitten.

The game refocusing device is preferably in the form of a monolithic component. This component can be made of either metal or alloy, or silicon, or an elastomeric plastic material. When the spring is metal, alloy or silicon, one can achieve its contour for example by etching, or photolithography and galvanic growth. In the case of a plastic material, for example, the injection-molding technique will be used.

The shock absorbing bearing and its game refocusing device according to the present invention makes it possible to cancel the centering or support uncertainty of the kitten, linked to the intolerance of the components, thanks to the active self-centering effect. and, in the case of the return effect of the second part of the game refocusing device, the centering element 42 of the game refocusing device according to the invention. is reminded up. The positioning of the inner centering wall of the centering element will fit against the outer conical wall of the bearing support centering at a height depending on the set of tolerances: if there is little play, the positioning is down, and if there is a lot of play, the positioning is high. This makes it possible to cancel the uncertainty of centering or support of the bearing support, linked to the intolerance of the components. In addition, the bearing support can be both centered and supported flat, which is essential to this balance guide component.

Naturally, the invention is not limited to the embodiments described with reference to the figures and variants could be envisaged without departing from the scope of the invention. For example, the counter-pivot and the elastic member could be made in one piece. In addition, although the centering walls of the bearing support and the centering element of the game refocusing device are of conical shapes, the taper of the inner centering wall 43a of the centering element 42 corresponding preferably at the conicity of the outer centering wall 23b of the bearing support 20, other profiles of the centering walls could be adapted to perform the centering function. In particular, the outer centering wall 23b of the bearing support 20 may be convex, the inner centering wall 43a of the centering element 42 being conical, or the outer centering wall of the bearing support may be conical, the inner wall centering piece 43a of the centering element 42 being convex.

Claims (12)

claims 1. Shock absorbing bearing (10) for an axis of a mobile of a timepiece, in particular for a balance shaft, comprising a bearing block (11) comprising a housing, a bearing support (20) arranged in the housing and comprising an outer centering wall (23b), a pivot bearing (24) mounted on the bearing support (20) for receiving a pivot of the axis of a mobile and an elastic support arrangement ( 25) of the pivot axis of the mobile, the shock absorbing bearing (10) further comprising a game refocusing device (40), characterized in that the game refocusing device (40) comprises, a on the one hand, a first part comprising a centering element (42) having an inner centering wall (43a) in which the outer centering wall (23b) of the bearing support (20) is arranged, and on the other hand a second bearing part on the bearing block (11) and arranged so as to exert a return effect vis-à-vis the first part. 2. Bearing according to claim 1, characterized in that the outer centering wall (23b) of the bearing support (20) and the inner centering wall (43a) of the centering element (42) are each a conical wall , the taper of the inner centering wall (43a) of the centering element (42) corresponding to the taper of the outer centering wall (23b) of the bearing support (20). 3. Bearing according to claim 1, characterized in that the outer centering wall (23b) of the bearing support (20) is convex and the inner centering wall (43a) of the centering element (42) is conical. 4. Bearing according to claim 1, characterized in that the outer centering wall (23b) of the bearing support (20) is conical and the inner centering wall (43a) of the centering element (42) is convex. 5. Bearing according to one of claims 1 to 4, characterized in that the bearing block (11) has an inner wall comprising a cylindrical shoulder (16) having a radial bearing surface (16a) and a surface axial support (16b) and in that said second part of the game refocusing device (40) comprises an annular portion (46) arranged on the radial bearing surface (16a) of the shoulder (16) and a elastic portion extending beyond said radial bearing surface (16a) towards the axis of the bearing. 6. Bearing according to claim 5, characterized in that the elastic portion comprises a plurality of flexible blades (47) arranged along a preferably circular path, the flexible blades being configured to flex substantially axially under the effect of a shock and to compensate for axial clearances and to center the bearing support (20). 7. Bearing according to claim 6, characterized in that the centering element (42) comprises an outer wall (44) having a plurality of reinforcing and centering blocks (45), one and the other end of each flexible blade (47) being respectively connected to a corresponding block and to the annular portion (46) of the second portion of the game centering device (40). 8. Bearing according to claim 7, characterized in that each reinforcing block (45) has a bearing surface (45a) arranged against the axial bearing surface (16b) of the shoulder (16), each flexible blade (47) comprising an outer side wall (47a) set back from the bearing surface of each block. 9. Bearing according to any one of claims 6 to 8, characterized in that the axis of curvature of the flexible blades (47) of the resilient portion corresponds to the axis of the bearing. 10. Bearing according to any one of claims 5 to 9, characterized in that the annular portion (46) of the second portion of the game refocusing device (40) has a square or rectangular cross section, the annular portion being in prestressing to exert a force against a corner formed by the radial bearing surface (16a) of the shoulder (16) and an axial bearing surface (15a) of the inner wall of the bearing block (11). 11. Bearing according to any one of the preceding claims, characterized in that the bearing block (11) comprises a base (12) comprising an opening (13) for the passage of the pivot of the axis of a mobile, the bearing support (20) being supported on the base (12), the centering element (42) of said first portion being remote from the base (12) when the bearing is in a rest configuration. 12. Watch movement comprising a plate and at least one bridge, said plate and / or the bridge having an orifice in which is inserted the bearing according to any one of the preceding claims.