Assembly of two micromechanical parts

Abstract

The invention relates to an assembly (10) comprising a first and a second micromechanical parts (11, 20) cooperating with each other, the first part (11) comprising a board (12) from which extends a connecting element (13) formed by a projecting body comprising at least one radial bearing surface (130) defining a surface of revolution, and at least one axial bearing surface (131) formed by a shoulder (132) extending radially and generating an overthickness on the board (12), the connecting element (13) of the first part (11) cooperating according to a pivot connection with a complementary connecting element (21) of the second part so that the axial bearing surfaces (131) and radial bearing surfaces (130) receive the second part in support.

Description

Technical field of the invention

[0001] The invention falls within the field of micromechanics and more specifically watchmaking.

[0002] More specifically, the invention relates to an assembly comprising a first and a second micromechanical part. Technological background

[0003] In the field of watchmaking, when two parts assembled together are intended to be pivoted relative to each other, they are arranged in contact with each other by a radial support and by an axial support.

[0004] In particular, in the case of a wheel 1 fixed in a movable rotation on an axis 2 of a moving part 3, the wheel 1 rests axially on a support formed on a plate 4 of a wheel or pinion of the moving part 3. This support is generally formed by an annular boss 5, as visible in the cross-sectional view of the figure 1This type of construction is, for example, often used for guiding a date disc.

[0005] This annular boss 5 can be produced by machining in turning or milling.

[0006] Milling can be carried out with a cutting tool having a shape complementary to the annular boss 5. In this case, the tool is moved in plunge along an axis passing through the center of the annular boss 5.

[0007] The disadvantage of this type of machining is that it requires a tool specific to each part of different dimensions or to each different boss profile.

[0008] The annular boss 5 can also be generated by milling with a conventional cutting tool. However, this operation, when possible, can be delicate since the distance between the annular boss 5 and the axis 2 of the moving part 3 defines the maximum diameter of the cutting tool, and this dimension can be extremely small, for example on the order of a tenth of a millimeter.

[0009] In any case, whatever the manufacturing process of this annular boss 5, due to its very small dimensions and shape, it is long and expensive to implement.

[0010] Therefore, there is a need to create an assembly where the manufacturing of the parts is simplified. Summary of the invention

[0011] The invention overcomes the aforementioned drawbacks and, to this end, relates to an assembly comprising a first and a second micromechanical part cooperating with each other. The first part comprises a board from which extends a connecting element formed by a projecting body comprising at least one radial bearing surface defining a surface of revolution, and at least one axial bearing surface formed by a shoulder extending radially and generating an additional thickness on the board.

[0012] The connecting element of the first part cooperates via a pivot joint with a complementary connecting element of the second part so that the axial and radial spans receive the second part in support.

[0013] Thanks to these characteristics, the assembly parts are relatively simple to machine, even with conventional cutting tools.

[0014] In particular embodiments, the invention may further comprise one or more of the following features, taken individually or in all technically possible combinations.

[0015] In particular embodiments, the connecting element has at least one axial groove intended to reduce the contact area between the first and second part and extending between a distal end opening onto a free end of the connecting element and a proximal end opening onto the or one of the axial bearing surfaces.

[0016] In particular embodiments, the connecting element comprises at least three radial spans separated from each other by regularly distributed grooves so that the radial spans extend over an angular sector substantially identical to each other.

[0017] In particular embodiments, the radial span or one of the radial spans is elastically deformable in a radial direction, said radial span being deformed when the connecting element cooperates with the complementary connecting element of the second part.

[0018] In particular embodiments, the radial span capable of deforming is formed by an elastic blade extending along a curvilinear direction.

[0019] In particular embodiments, the elastic blade is configured so as to extend radially beyond the surface of revolution. Brief description of the figures

[0020] Other features and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting example, with reference to the accompanying drawings in which: There figure 1represents a perspective view of a wheel fixed in a movable manner rotating on an axis of a moving object according to a design of the prior art, The figure 2 represents a detailed perspective view of a connecting element of a first part of a micromechanical assembly according to an exemplary embodiment of the invention, The figure 3 schematically represents a cross-sectional view of the first piece of the figure 2 cooperating with a second part so as to form an assembly according to an example of an embodiment of the invention, The Figures 4 and 5 represent a perspective view of the first room of the figure 2 according to other examples of implementation of the invention.

[0021] Note that the figures are not necessarily drawn to scale for reasons of clarity. Detailed description of the invention

[0022] The present invention relates to an assembly 10 comprising a first and a second micromechanical part 11 and 20 cooperating with each other according to a pivot joint.

[0023] There figure 2 shows a first part 11 of the assembly 10 in a first embodiment of the invention. The assembly 10 is shown in cross-sectional view on the figure 3 .

[0024] This first part 11 includes a board 12 from which extends a connecting element 13 formed by a projecting body and with which cooperates a complementary connecting element 21 of the second part 20 when the first and second parts 11 and 20 are assembled.

[0025] The connecting element 13 may be in the form of a shaft, rod, stud, pin, or any other projecting shape. The connecting element 13 comprises at least one radial bearing surface 130 defining a surface of revolution, and at least one axial bearing surface 131 formed by a shoulder 132 extending radially and generating a raised area on the plate 12, as seen in the figure 3 .

[0026] The surface of revolution formed by the radial span 130 is preferably in the shape of a right cylinder, but can alternatively be of any other geometric shape.

[0027] The connecting element 13 of the first part 11 is configured so that when it cooperates with the complementary connecting element 21 of the second part, the second part rests against the radial 130 and axial 131 spans.

[0028] Advantageously, the connecting element 13 may include at least one axial groove 133, such as a spline, intended to reduce the contact area between the connecting element 13 and the second part 20. Such a groove 133 has a distal end opening onto a free end of the connecting element 13, i.e., its apex, and a proximal end at the base of the connecting element opening onto one or more of the axial bearing surfaces 131. In particular, as shown by the figures 2 , 4 and 5, the axial bearing surface 131 extends over an angular sector corresponding at most to the width of a groove 133, so that the axial bearing surface 131 extends only in relation to a groove 133. Thus, the axial bearing surfaces 131 and the radial bearing surfaces 130 extend along strictly different angular sectors, which makes it possible to avoid any support of the second part 20 against a fillet formed at the base of the radial bearing surfaces 130 by a machining operation, during the making of the connecting element 13, and consequently any uncertainty of position of the second part 20.

[0029] The groove(s) 133 also help to reduce the risk of butting of the second piece 20.

[0030] In the example of an embodiment of the invention shown in the figure 2The connecting element 13 comprises three radial bearing surfaces 130 separated from each other by a groove 133. The grooves 133 are, for example, regularly distributed around the connecting element 13 so that the radial bearing surfaces 130 extend over an angular sector, for example, identical to each other. Thus, the mechanical connection is advantageously isostatic.

[0031] Advantageously, as can be seen in the examples of implementation of the Figures 4 and 5 The connecting element 13 can be configured so that at least one of the radial bearing surfaces 130 is elastically deformable in a radial direction. The deformable radial bearing surface 130 is intended to deform when the connecting element 13 interacts with the complementary connecting element 21 of the second part 20, thereby further controlling the mechanical clearance between the connecting element 13 and the complementary connecting element 21.

[0032] The deformable radial span 130 is preferentially formed by an elastic blade 134, as can be seen on the figure 4 This elastic blade 134 comprises two longitudinal ends by which it is connected to the connecting element 13. Alternatively, as visible on the figure 5 The elastic blade 134 can be connected to the connecting element 13 at only one end, its other end being free. In these two embodiments, the elastic blade 134 extends along a curvilinear direction preferably centered on the axis of revolution of the surface of revolution formed by the radial spans 130.

[0033] It is also conceivable that the elastic blade 134 is configured so as to extend radially beyond the surface of revolution formed by the radial bearings 130. In this case, the second part 20 has one or more radial notches, for example formed by teeth, suitable for cooperating with the blade so as to form a ratchet or any other angular position indexing mechanism.

[0034] The elastic blade 134 is made by machining an opening 135 in the connecting element 13 and in the plate 12, as can be seen on the Figures 4 and 5 .

[0035] Thanks to the features of the invention, the manufacture of the first part 11, and in particular the machining of the connecting element 13, is particularly simple to carry out, insofar as the machining can be carried out with a single conventional cutting tool, such as a two-size milling cutter.

[0036] More generally, it should be noted that the implementation and execution methods considered above have been described as non-limiting examples, and that other variants are therefore conceivable.

[0037] In particular, on the figures 2 to 5 , the connecting element 13 is shown as having radial spans 130 on its outer periphery and the complementary connecting element 21 is shown on the figure 3 supported against the radial spans 130 by its inner periphery, but it is conceivable that the radial spans 130 are arranged on an inner periphery of the connecting element 13 and that the complementary connecting element 21 rests supported against the radial spans 130 by its outer periphery.

[0038] Thus, the connecting element 13 can be formed by a cavity in which the complementary connecting element 21 is engaged, then formed by a protruding body, such as a shaft, a rod, a pin, a nipple, etc.

Claims

1. Assembly (10) comprising a first and a second micromechanical part (11, 20) cooperating with each other, characterized in that the first part (11) includes a board (12) from which extends a connecting element (13) formed by a projecting body comprising at least one radial span (130) defining a surface of revolution, and at least one axial span (131) formed by a shoulder (132) extending radially and generating an overthickness on the board (12), the connecting element (13) of the first part (11) cooperating according to a pivot connection with a complementary connecting element (21) of the second part so that the axial spans (131) and radial spans (130) receive the second part in support.

2. Assembly (10) according to claim 1, wherein the connecting element (13) has at least one axial groove (133) intended to reduce the contact area between the first and second part and extending between a distal end opening onto a free end of the connecting element (13) and a proximal end opening onto the or one of the axial bearing surfaces (131).

3. Assembly (10) according to any one of claims 1 to 2, wherein the connecting element (13) comprises at least three radial bearing surfaces separated from each other by regularly distributed grooves (133) so that the radial bearing surfaces extend over an angular sector substantially identical to each other.

4. Assembly (10) according to any one of claims 1 to 3, wherein the radial span (130) or one of the radial spans is elastically deformable in a radial direction, said radial span (130) being deformed when the connecting element (13) cooperates with the complementary connecting element (21) of the second part.

5. Assembly (10) according to any one of claims 1 to 3, wherein the radial span (130) capable of deforming is formed by an elastic blade (134) extending in a curvilinear direction.

6. Assembly (10) according to claim 5, wherein the elastic blade (134) is configured so as to extend radially beyond the surface of revolution.

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