• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a bearing in which an axis (30) pivots, the axis (30) comprising at least one end a bearing surface (31a, 31b) via which the axis (30) is in contact with a surface (12). ) facing the bearing (10a, 10b), the bearing surface (31a, 31b) being extended by a pivot (32a, 32b) engaged in a hole (11) formed in the bearing (10a, 10b), the bearing (10a, 10b) being characterized in that the contact surface (12) facing the bearing (10a, 10b) comprises at least one recess (14) to reduce the contact area between the bearing surface (31a, 31b) (30) and the bearing (10a, 10b). Application to the realization of a bearing for a watch movement axis.
    公开号:CH712587B1
    申请号:CH00211/17
    申请日:2017-02-23
    公开日:2017-12-29
    发明作者:Kaelin Laurent；Chopard-Lallier Pascal；Besutti Bruno
    申请人:Comadur Sa；
    IPC主号:
    专利说明:

    Description
    TECHNICAL FIELD OF THE INVENTION [0001] The present invention relates to a bearing in which is pivotable an axis, the axis comprising at least one end a span through which the axis is in contact with a surface facing the bearing said bearing being extended by a pivot engaged in a hole in the bearing. Such a bearing is particularly used in the field of watchmaking.
    BACKGROUND OF THE INVENTION [0002] To drive a wheel in rotation in a clockwork movement, it is known to fix the wheel on an axis comprising at least one of its ends an extended range by a pivot. The axis is positioned between two bearings each comprising a hole in which is housed a pivot axis. According to the chosen construction method, the range of one end of the axis or the range of each end of the axis comes into contact with a surface facing the associated bearing. Both bearings guide the axis in rotation while prohibiting its axial translation.
    To limit the friction between the axis of the bearing and the bearing, it is known to provide a recess on an outer edge of the hole in which is housed the axis of the pivot so as to achieve a reservoir commonly called huilier and intended to receive a drop of oil. The drop of oil in the reservoir is infiltrated by capillarity between the axis and the walls of the bearing hole and between the bearing surface of the axis and the surface of the bearing facing said bearing surface. This technique reduces friction between the axis and the bearing. However, the oil layer between the axis of the bearing and the surface facing the bearing is particularly thin so that there is a bonding effect between the axis of the bearing and the surface facing the bearing and, when the axis rotates, a shearing force of the oil layer comes to oppose the rotation of the axis. These parasitic phenomena result in a loss of energy that we try to avoid. SUMMARY OF THE INVENTION [0004] The present invention aims at improving the known technique, by proposing a solution for reducing the shearing force at the level of the oil layer present between the span of an axis and the surface facing the surface. a bearing in which the axis is rotated.
    For this purpose, the present invention relates to a bearing in which pivots an axis, the axis comprising at one end a bearing via which the axis is in contact with a surface facing the bearing, said bearing being extended by a pivot engaged in a hole in the bearing, the bearing surface facing the axis of the bearing comprising at least one recess to reduce the contact area between the axis of the bearing and the bearing.
    By reducing the contact area between the bearing axis and the bearing, the effect of the shear force of the oil layer is reduced. The axis thus pivots more easily in the bearing. In addition, even reduced, the contact surface remains sufficient to guide the axis in the bearing.
    According to one embodiment of the invention, the recess is in the form of a ring centered on the bearing hole. The effect, ie the torque produced by the elementary shear force, is the product of this shearing force by the distance between the axis of rotation and the point of application of the elementary force. By making an annular recess away from the pivot axis, thus further reduces the effects of the shear force.
    According to another embodiment of the invention, the facing surface of the bearing by which the bearing surface of the shaft is in contact with the bearing is provided with a plurality of recesses distributed around the hole of the bearing. The reduction of the effect of the shearing force is thus more homogeneous between the bearing of the axis and the surface of the bearing opposite the span of the axis.
    BRIEF DESCRIPTION OF THE FIGURES [0009] Other features and advantages of the present invention will emerge more clearly from the following detailed description of embodiments of bearings according to the invention. These examples are given for purely illustrative and non-limiting purposes and are to be read in conjunction with the accompanying drawings in which: FIG. 1 is a view of a wheel of a clockwork movement rotatably mounted between two bearings according to the invention; fig. 2 is a top view of a bearing according to the invention, and FIG. 3 is a top view of another bearing according to the invention.
    DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION [0010] The present invention proceeds from the general inventive idea of limiting the contact area between the range of an axis and the surface facing a bearing now. said axis. For this purpose, the invention proposes a new bearing whose general shape limits said contact surface.
    FIG. 1 schematically shows the implementation of bearings according to the invention for driving in rotation of a toothed wheel of a watch movement.
    The toothed wheel 20 is fixed on an axis 30 comprising at each end a bearing 31a, 31b extended by a pivot 32a, 32b. The axis 30 is rotatably mounted between two bearings 10a, 10b according to the invention. The bearings 10a, 10b, preferably of annular shape, are immobilized in a frame 21. These bearings 10a, 10b comprise, in known manner, a hole 11, preferably centered, which passes through them from one side. Note that the wall of the hole 11 may include an olivage to minimize contact with the pivots 32a, 32b and facilitate possible lubrication.
    A pivot 32a, 32b of the axis 30 guided in rotation by the corresponding bearing 10a or 10b is housed in the hole 11. The bearing 31a, 31b of the axis 30 comes into contact with a surface 12 facing of the bearing 10a, 10b, so that the axis 30 is immobilized in axial translation, a clearance, between the bearings 10a, 10b.
    On a face opposite to the contact surface 12 between the bearing surface 31a, 31b of the axis 30 and the bearing 10a, 10b, the hole 11 opens into a recess 13 of preferably conical shape. This hollow 13, commonly called oiler in the field of watchmaking, may be intended to receive a drop of oil. The other end of the hole 11 is slightly flared to facilitate the infiltration of the oil between the bearing 10a, 10b and the bearing surface 31a, 31b at the contact surface 12. It will be understood that this recess is optional and that it will be provided only in the case where it is desired to lubricate the pivoting of the axis 30 in the bearing 10a, 10b.
    A bearing 10a, 10b according to the invention is characterized by a recess 14 for reducing the contact surface 12 between the bearing 31a, 31b of the axis 30 and the bearing 10a, 10b. The recess 14 is formed on the opposite side to the recess 13, in the contact surface 12 of the bearing 10a, 10b which is opposite the bearing surface 31a, 31b of the axis 30.
    According to an embodiment illustrated in FIG. 2, the recess 14 has an annular shape. The residual contact surface 12 between the bearing surface 31a, 31b of the axis 30 and the bearing 10a, 10b thus has the shape of two concentric inner 12a and outer 12b rings. The inner radius RO of the inner ring 12a is substantially equal to the radius of the hole 11, while the outer radius R1 of the inner ring 12a is equal to the inner radius of the recess 14. As to the outer concentric ring 12b it is between an inner radius R2 equal to the outer diameter of the recess 14, and an outer radius R3. The diameter R1 must be sufficient to ensure proper maintenance of the axis 30 in the hole 11.
    According to another embodiment, several recesses 14 are hollowed on the surface of the bearing 10a, 10b around the hole 11. In the example shown in FIG. 3, six recesses 14 are evenly spaced, arranged concentrically around the pivot 32a, 32b of the axis 30 and opening into the flared end of the hole 11.
    In the field of watchmaking, the dimensions of the bearings are small, less than 1 mm to a few millimeters for the largest dimension. The production of a bearing according to the invention is therefore delicate and requires specific tools.
    Alternatively, the bearing 10a, 10b is made of a monocrystalline hard material such as ruby, corundum, spinel or even cubic zirconia and the recesses 14 are machined by ablation of material by means of a laser beam, electroerosion or grinding.
    According to another variant, the bearing 10a, 10b is made of a hard sintered material such as corundum, ruby, ceramics, alumina, zirconia or a hard metal and the recesses 14 are made by forging or machined by ablation. This technique is described in particular in document EP 2 778 801 A1 in the name of the Applicant.
    Remember for the record that the method comprises a first step for forming a ceramic precursor from a ceramic powder taken in a binder. This ceramic-based powder may comprise at least one metal oxide, a metal nitride or a metal carbide. For example, the ceramic powder may comprise aluminum oxide to form synthetic sapphire or a mixture of aluminum oxide and chromium oxide to form synthetic ruby. As for the binder, it can be of the polymer type or of the organic type.
    The method comprises a second step for compressing, using an upper die and a lower die that is brought closer to one another, the ceramic precursor to form a green body. of the future bearing 10a, 10b with upper and lower surfaces respectively comprising at least one recess 14 and, where appropriate, a recess 13. It is therefore understood that each green body thus formed already comprises the blanks of the recess 14 and the hollow 13.
    To obtain these blanks of the recess 14 and the recess 13, each substantially planar matrix comprises at least one punch intended to form the recess 14 and, optionally, the recess 13. For this purpose, the upper die comprises a punch with a substantially annular surface for forming the recess 14, and the lower die has a punch with a substantially conical surface for forming the recess 13.
    Finally, the green body is sintered to form a ceramic bearing 10a, 10b and the hole 11 is drilled to connect the upper surface and the lower surface of the bearing 10a, 10b. This step is preferably carried out using destructive radiation of the laser type in order to obtain a very precise etching. However, this step can be performed for example by mechanical drilling or etching with high pressure water.
    权利要求:
    Claims (6)
    [1]
    Bearing in which pivots an axis (30), the axis (30) comprising at least one end a bearing (31a, 31b) via which the axis (30) is in contact with a surface (12) of the bearing (10a, 10b) facing it, the axis (30) being extended on the bearing side (31a, 31b) by a pivot (32a, 32b) engaged in a hole (11) in the bearing (10a, 10b), the bearing (10a, 10b) being characterized in that the contact surface (12) of the bearing (10a, 10b) which faces the bearing surface (31a, 31b) of the axis (30) comprises at least a recess (14) to reduce the contact area between the bearing surface (31a, 31b) of the shaft (30) and the bearing (10a, 10b).
    [2]
    2. Bearing according to claim 1, characterized in that the recess (14) is in the form of a ring centered on the hole (11) of the bearing (10a, 10b).
    [3]
    3. Bearing according to claim 1, characterized in that the contact surface (12) between the bearing surface (31a, 31b) of the axis (30) and the bearing (10a, 10b) is provided with a plurality of recesses (14) distributed around the hole (11) of the bearing (10a, 10b).
    [4]
    4. Bearing according to claim 3, characterized in that the recesses (14) are evenly spaced and arranged concentrically around the hole (11) of the bearing (10a, 10b).
    [5]
    5. Bearing according to one of claims 1 to 4, characterized in that it is made of a monocrystalline material selected from the group consisting of ruby, corundum, spinel or cubic zirconia, the recess (14) being machined by ablation by means of a laser beam, electroerosion or grinding.
    [6]
    6. Bearing according to one of claims 1 to 4, characterized in that it is made of a sintered material selected from the group consisting of sintered corundum, sintered ruby, sintered ceramics, sintered alumina, zirconia sintered or a sintered hard metal, the recess (14) being made by stamping or machined by ablation.
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    同族专利:
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    CH17202016|2016-12-23|
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