Classifications

• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B15/00—Escapements
  • G04B15/14—Component parts or constructional details, e.g. construction of the lever or the escape wheel
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B13/00—Gearwork
  • G04B13/02—Wheels; Pinions; Spindles; Pivots
  • G04B13/021—Wheels; Pinions; Spindles; Pivots elastic fitting with a spindle, axis or shaft
  • G04B13/022—Wheels; Pinions; Spindles; Pivots elastic fitting with a spindle, axis or shaft with parts made of hard material, e.g. silicon, diamond, sapphire, quartz and the like
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49462—Gear making
  • Y10T29/49465—Gear mounting

Definitions

• the present invention relates to a micro-mechanical part comprising a shaped opening intended to facilitate assembly on an axis for a moving part, or on a stud for a fixed part, and to limit or eliminate the risk of breaking the part during the driving on the axis or the stud, especially when said part is made of a brittle material.
• the driving technique is very widely used, for example for securing a wheel on a shaft.
• material constituting the part has a plastic domain, which is the case of metals and alloys, it is known to calculate the tolerances necessary for the shaft and the bore so as to have a tight fit without risk of breaking the part, or of to deform it.
• plastic field which is the case of glass, quartz or silicon, there is a great risk of breaking the workpiece during assembly.
• the present invention therefore aims to overcome the disadvantages of the aforementioned prior art by providing a micromechanical part, in particular watchmaker, made of a brittle material which can be assembled by driving on an axis or a stud without risk of rupture.
• the invention relates to a micro-mechanical part made from a plate of a brittle material having an opening for driving an axis or a stud.
• brittle material is meant a material having no plastic deformation domain, such as glass, quartz or silicon.
• the invention is characterized in that the opening is a "shape opening", that is to say an opening that does not have a perfectly circular contour, said opening alternately comprising zones of stiffening and positioning and zones with elastic deformation ensuring the tightening of the axis.
• the zones with elastic deformation consist of plate portions having on both sides a recess joining the opening and the end of which penetrates into said opening. These plate portions are in the form of a tongue that presses tangentially on the axis during the driving.
• the stiffening and positioning zones and the tongues are arranged alternately about the axis, each tongue being separated from the adjacent stiffening zones by a recess, and the stiffening and positioning zones are distributed in a substantially regular manner around the opening.
• each stiffening and positioning zone having at least one bearing surface intended to be in contact with the axis, the bearing surfaces are distributed substantially uniformly around the opening to ensure the centering of the axis in the opening; each stiffening and positioning zone constitutes a span which is delimited by the two recesses flanking said stiffening and positioning zone;
• each tab generally describes a determined profile curve, and the two adjacent recesses are constituted by two generally elongated slots of the same profile as the curve of said tongue;
• the brittle material is chosen from glass, quartz and silicon.
• the invention also proposes an arrangement for immobilizing a micro-mechanical part comprising an opening by driving on a support block comprising a positioning stud.
• the micro-mechanical part is made with any of the preceding features.
• the invention also proposes an arrangement for fixing by driving a moving micro-mechanical part in rotation, continuous or alternative, on a shaft.
• the micro-mechanical part is made with any one of the preceding claims. According to variants of this arrangement:
• the micro-mechanical part is a part of a watch movement selected from an escape wheel, a star, a toothed wheel, a ferrule, a lever and an anchor;
• the axis and the opening also have outlines providing an anti-rotation effect;
• the contour of the axis and the opening is oblong or triangular;
• the zones in contact with the axis and the opening are provided with roughness or grooves
• the micro-mechanical part comprises at least one welding point or an adhesive point fixing the micro-mechanical part on the axis.
• Figure 2 is a top view of the first embodiment applied to an escape wheel
• Fig. 3 is a top view of a second embodiment applied to a star
• Fig. 4 is a top view of a third embodiment applied to a gear wheel
• Figure 5 is a view similar to that of Figure 2 which shows a preferred embodiment of the invention.
• FIG. 1 represents in perspective a portion of plate 1 to be secured to a support block 1 1 by means of a cylindrical stud 3 passing through an opening 2 formed in said plate 1.
• the plate 1 is constituted by a brittle material, c ' that is to say a material having no plastic domain in the normal temperatures of use, such as glass, quartz or silicon.
• the plate 1 may simply be a construction element, for example a plate, a bridge or a dial of a timepiece. It can also have a functional role by supporting a printed circuit or MEMs to be secured to the block 1 1.
• the opening 2 is a shaped opening shown in view of on a larger scale in Figure 2.
• FIG. 2 shows, by way of example, a silicon escapement wheel mounted on a cylindrical shaft intended to be pivoted between two bearings.
• the contour of the opening 2 does not follow the circular contour of the shaft 5 by alternately presenting stiffening and positioning zones 8 and zones 10 with elastic deformation.
• the zones 8 of stiffening and the zones 10 with elastic deformation extend in the plane of the plate 1, as represented in FIGS. 1 and 2, since they define the shape of the opening 2.
• the zones 10 with elastic deformation are provided to deform in the plane of the plate 1.
• the stiffening zones 8 serve to center the escape wheel with respect to the shaft 5.
• the stiffening zones 8 are distributed angularly in a regular manner around the opening 2.
• the zones with elastic deformation 10 are obtained by producing in the wafer 1 recesses 13, 15 opening into the central opening and delimiting in this example a tongue 12 whose end 14 extends beyond the theoretical contour of the shaft 5 and thus ensures a clamping function when the shaft 5 in place by driving.
• each tongue 12 is separated from the adjacent stiffening zones 8 by a recess 13, 15, so that each tongue 12 is connected to the wafer 1 in a zone distinct from the stiffening zones 8.
• the tabs 12 are distributed angularly in a regular manner around the shaft 5, between the zones 8 of stiffening.
• the opening 2 thus has alternately, on its periphery, a stiffening zone 8 and a tongue 12.
• each tongue 12 generally describes a determined profile curve, here an arcuate curve.
• the two adjacent recesses 13, 15 are constituted by two generally elongated slots of the same profile as the curve of said tongue 12.
• FIG. 5 represents a preferred embodiment of the invention similar to that of FIG. 2, in which the zones 8 of stiffening are represented such that they are in reality, that is to say without exaggerating the space 9 between said zones 8 and the shaft 5.
• each stiffening zone 8 comprises at least one bearing surface 16 intended to be in contact with the cylindrical wall of the shaft 5. These bearing surfaces 16 are distributed in a regular manner around of the opening 2 to ensure the centering of the shaft 5 in the opening 2. More particularly, each zone 8 of stiffening constitutes a bearing surface 16 which is delimited by the two recesses 13, 15 surrounding said zone 8.
• Each zone 8 The stiffening element therefore has an arcuate profile which generally follows the radius of curvature of the cylindrical wall of the shaft 5.
• the bearing surfaces 16 allow precise positioning of the wheel relative to the shaft 5.
• the tongues 12 ensure the fo radial clamping function, the catch-up function of the manufacturing sets at the opening, and they guarantee the centering of the shaft 5 in the opening 2.
• the number of zones 8 of stiffening and the number of 12 tabs could be more important than the one shown.
• Figure 3 corresponds to a second embodiment showing a timer star having in its center a shape of opening 4 providing an anti-rotation effect.
• the end 7 of the shaft 5 is machined with a non-circular contour in the shape of a triangle with rounded corners.
• the shape opening 4 follows this contour, but having, as in the first embodiment, a succession zones 8 for stiffening and positioning and areas 10 for elastic deformation.
• FIG. 4 corresponds to a third embodiment in which the part, for example made of silicon, is a toothed wheel having at its center a shaped opening 6 having as before an "anti-rotation" function.
• the shape opening 7 is oblong.
• Glue or solder completes fastening by elastic tongues.
• the fastening by the tongues constitutes an intermediate fixing step guaranteeing a precise centering of the axis in the opening, with a recovery of the clearances, and the step of bonding or welding constitutes a final fixing step.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Micromachines (AREA)
• Length-Measuring Instruments Using Mechanical Means (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Publications (2)

Family

ID=37560754

Family Applications (2)

Family Applications Before (1)

Country Status (10)

Families Citing this family (58)

Family Cites Families (13)

• 2006
  • 2006-02-28 EP EP06004074A patent/EP1826634A1/de not_active Withdrawn
• 2007
  • 2007-02-23 WO PCT/EP2007/051775 patent/WO2007099068A1/fr active Application Filing
  • 2007-02-23 DE DE602007010593T patent/DE602007010593D1/de active Active
  • 2007-02-23 US US12/280,836 patent/US8206029B2/en active Active
  • 2007-02-23 EP EP07704705A patent/EP1991916B1/de active Active
  • 2007-02-23 KR KR1020087021187A patent/KR20080111446A/ko not_active Application Discontinuation
  • 2007-02-23 CN CN200780006940XA patent/CN101390022B/zh active Active
  • 2007-02-23 AT AT07704705T patent/ATE488788T1/de not_active IP Right Cessation
  • 2007-02-23 JP JP2008556757A patent/JP4894052B2/ja active Active
  • 2007-02-27 TW TW096106845A patent/TWI434155B/zh not_active IP Right Cessation
• 2009
  • 2009-09-08 HK HK09108235.9A patent/HK1132050A1/xx unknown

Non-Patent Citations (1)

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