CH717166A2 - Bearing for watch movement. - Google Patents

Abstract

The invention relates to a bearing (1) for a watch movement, characterized in that it is in a single-piece and ceramic form and in that it comprises a first guide portion (1a) suitable for guiding a first one. watch mobile (2) and a second guide portion (1b) capable of guiding a second watch mobile (3).

Description

The present invention relates to a bearing for a watch movement. It also relates to a watch movement and a timepiece as such comprising such a bearing.

[0002] It is common practice in watchmaking to guide, in particular to pivot, mobile devices by means of stones, plugs or tenons. We also use the generic term of bearing to designate the element which makes it possible to guide at least one watch mobile. By watchmaking mobile, we mean any component or any assembly comprising an element intended to move, in particular to pivot and / or translate, within a timepiece movement.

In the state of the art, it is noted that the existing bearings often have the first drawback of having a complex shape, for example in several distinct parts, in particular when it is necessary to guide several watch mobiles. They also have the second drawback of inducing a high and non-optimal friction torque, in particular because of their construction in copper alloy or in steel.

[0004] Thus, the object of the present invention is to improve the bearings used in watch movements.

[0005] More precisely, the object of the invention is to be able to manufacture a bearing allowing the guiding of the movement of at least two watch mobiles, while being robust, and minimizing the resulting friction.

[0006] To this end, the invention is based on a bearing for a watch movement, characterized in that it is in a single piece and ceramic form and in that it comprises a first guide portion suitable for guiding a first watch mobile and a second guide portion capable of guiding a second watch mobile.

The bearing for a watch movement may have a substantially tubular shape arranged around an axis of the bearing and having a height Ht along this axis of the bearing, and comprising a main external diameter De in a plane perpendicular to this axis of the bearing, this main outer diameter De corresponding in particular to the diameter at a guide portion arranged on an outer surface of the bearing and / or corresponding to the portion of constant outer diameter of greatest height of the bearing, and the bearing having a shape respecting l 'interval 0.8≤ Ht / De ≤ 5, or even 1≤ Ht / De ≤ 3, or even 1.2≤ Ht / De ≤ 2.4

[0008] The bearing for a watch movement may comprise a bore of cylindrical shape, in particular of diameter Di respecting the interval 1 <De / Di ≤ 5, or even 1.5≤ De / Di ≤ 3.

The bearing may have an outer surface, a first part of which forms said first guide portion and a second part of which forms said second guide portion; Where The bearing may have a bore, a first part of which forms said first guide portion and a second part of which forms said second guide portion; Where The bearing may have an outer surface and a bore, at least part of the outer surface forming said first guide portion and at least part of the bore forming said second guide portion.

[0010] The bearing may comprise an outer surface comprising: at least one part of cylindrical and smooth shape forming a guide portion of the bearing; and or at least one part forming an assembly surface, in particular driving surface, of the bearing with a blank, in particular a plate or a bridge; and or at least a portion of threaded surface.

The bearing may have a substantially tubular shape arranged around an axis of the bearing and may have a surface in a plane perpendicular to the axis of the bearing forming a stop surface for the axial retention of a watch mobile and / or for the axial positioning of the bearing, said abutment surface being in particular formed by a surface arranged on one end of the bearing and / or being formed by an enlarged portion of larger outside diameter of the bearing.

The bearing may have a tubular shape, the outer surface of the bearing of which is cylindrical with a constant diameter over substantially the entire height of the bearing.

The bearing can be in one piece.

The bearing may be made of ceramic chosen from a zirconia, in particular a yttriated zirconia, in particular a 3% yttriated zirconia, a monocrystalline alumina or an alumina-zirconia combination (ATZ).

The invention also relates to a watch movement, characterized in that it comprises a bearing as described above.

The first guide portion and the second guide portion of the bearing can each allow a guiding in rotation and / or in translation of a respective watch mobile of the watch movement.

[0017] The horological movement can comprise a first timer mobile clock and a second clockwork mobile of a finishing chain of a basic movement comprising a pivot, in particular an average mobile comprising a pivot, and the bearing can comprise an outer surface and a bore, at least part of the outer surface of the bearing forming said first guide portion and at least part of the bore forming said second guide portion, the first guide portion of the bearing cooperating with the first watch mobile timer and the second guide surface cooperating with the pivot of the second watch mobile.

[0018] The horological movement may comprise a first watch mobile which is a winding crown comprising a bore and a second watch mobile crown comprising a shaft, and the bearing may include an outer surface and a bore, at least part of the outer surface of the bearing forming said first guide portion and at least part of the bore forming said second guide portion, the first guide portion of the bearing cooperating with the bore of the winding crown and the second guide surface cooperating with the shaft of the second crown watch mobile.

The bearing of the watch movement may include an assembly surface (by which it is fixed in a blank, in particular a plate or a bridge, of the watch movement).

The invention also relates to a timepiece, characterized in that it comprises at least one bearing as described above or a watch movement as described above.

The invention also relates to a horological movement as such, and to a timepiece as such, such as a wristwatch.

The invention is more particularly defined by the claims.

These objects, characteristics and advantages of the present invention will be explained in detail in the following description of particular embodiments made without limitation in relation to the accompanying figures, among which: FIG. 1 shows a perspective view of a bearing according to a first variant of a first embodiment of the invention. FIG. 2 illustrates a watch movement incorporating a bearing according to the first variant of the first embodiment of the invention in section through a median plane at the level of the bearing. FIG. 3 illustrates an enlarged view of FIG. 2, at the level of the bearing. FIG. 4 illustrates a watch movement similar to that of FIG. 2 comprising a bearing according to a second variant of the first embodiment of the invention. FIG. 5 illustrates a watch movement incorporating a bearing according to a third variant of the first embodiment of the invention in section through a median plane at the level of the bearing. FIG. 6 represents a perspective view of a bearing according to a second embodiment of the invention. FIG. 7 illustrates a watch movement incorporating a bearing according to the second embodiment of the invention in section through a median plane at the level of the bearing. FIG. 8 illustrates a watch movement incorporating a bearing according to a third embodiment of the invention in section through a median plane at the level of the bearing.

According to the concept of the invention, a bearing has a shape suitable for guiding two separate watch mobiles, or even three or more. In addition, the bearing is ceramic and in a one-piece form. By combining these characteristics, the bearing allows a compact construction of a watch movement. The bearing according to the invention also makes it possible to minimize the frictional forces in contact with the watch mobiles.

Advantageously, the bearing for a watch movement according to the invention has a substantially tubular shape arranged around an axis which will be called “axis of the bearing”. The height Ht of the landing will be considered as its dimension along this axis of the landing. Due to its substantially tubular shape, we will be able to define a main external diameter De, which will be measured as a particular diameter of the bearing measured in a plane perpendicular to the axis of the bearing. As the outer diameter of the bearing can optionally vary, as will be described later, we will define this "main outer diameter" as the diameter measured at a guide portion arranged on an outer surface of the bearing and / or as the diameter. corresponding to the portion of constant outer diameter of greatest height of the bearing. In the advantageous embodiments of the invention, the bearing has an elongated shape respecting the interval 0.8 Ht / De 5, or even 1 Ht / De 3, or even 1.2 Ht / De 2.4.

Figure 1illustrates a first variant of a bearing 1 according to a first embodiment of the invention.

This bearing 1 has a tubular shape arranged around an axis of the bearing A1, and of constant outer diameter. Its outer surface 11 is smooth. This external diameter is constant over its entire height Ht, and corresponds to the main external diameter De of the bearing, with the exception of the two ends for which the diameter is progressively reduced so as to form rounded external surfaces, which facilitate assembly of the bearing. bearing 1 within a watch movement. In this first variant embodiment, the bearing 1 has an elongated geometry of the axis of the bearing A1, and has a form factor Ht / De of the order of 1.8.

The bearing 1 comprises, in addition, a 12cylindrical bore, arranged around the axis of the bearing A1, of constant diameter Di over the entire height Ht of the bearing, with the optional exception of the ends for which the surface is curved for avoid edges and facilitate cooperation of the bearing with a mobile or a blank of a watch movement.

This geometry forms annular surfaces at both ends of the bearing, in planes perpendicular to the axis of the bearing A1. These surfaces are likely to form stop surfaces 13, as will be specified below.

Figures 2 and 3 illustrate the arrangement of a bearing 1 according to this first variant of the first embodiment within a watch movement 100. In this implementation of the bearing, the latter is more particularly intended to pivot a mobile timer of a mechanism 20, as well as an average mobile of a finishing line 30.

A portion of the outer surface 11du bearing 1forms an assembly surface 1c. According to this embodiment, this assembly surface extends over approximately half of the height Ht of the bearing 1. The assembly surface 1c advantageously allows the bearing 1 to be driven out within a blank 4 of the watch movement. This blank 4 is a plate according to the illustrated embodiment.

On the other hand, the outer surface 11du bearing 1 comprises an additional portion forming a first guide portion 1a, which cooperates with a first mobile watchmaker 2 which is here the timer mobile of the mechanism 20. More particularly, the first portion of guide 1a cooperates with a bore 21du mobile timer.

The bore 12du bearing 1forms a second guide portion 1b, which cooperates with a pivot 31 of a second mobile clockwork 3, inserted within this bore 12. This second mobile clockwork 3 is here the average mobile of the chain 30. Furthermore, the abutment surface 13du bearing 1cooperates with a range 32du second mobile watchmaker. This cooperation ensures the relative axial retention of the two elements. It at least partially allows the axial movement of the watch mobile.

By this construction, the bearing 1 as described allows the arrangement of two mobile watchmakers 2, 3on either side of the blank 4, while optimizing their mode of pivoting relative to said blank 4.

FIG. 4 illustrates a second variant embodiment of a bearing 1 'of the first embodiment, which differs from the first variant by the formation of an enlarged portion 14' at one end of the bearing 1 ' , in the form of a cylindrical part of low height and of external diameter Dp greater than the main external diameter De of the bearing 1. The form factor Ht / De remains of the order of 1.8.

To insert this bearing 1 'within a watch movement 100' similar to that of Figures 2 and 3, a blank 4 'is slightly modified to form a step on the periphery of its opening in which the bearing 1' is hunt. The widened portion 14 'of the bearing 1' is positioned on said step of the blank. By this construction, the widened portion 14 'of the bearing 1' comprises a surface at the end of the bearing 1 'which forms a first abutment surface 13' against the second mobile. However, it also comprises an opposite surface 15 ′, which bears on the step of the blank, in the direction parallel to the axis of the bearing A1 ′, thus forming a stop which participates in the correct positioning of the bearing 1 ′ during its assembly with the blank 4 '.

In the two variant embodiments described above, the bearing 1, 1 'has an outer surface 11, 11' and a bore 12, 12 ', at least part of the outer surface 11, 11' forming a first guide portion 1a, 1a 'and at least part of the bore 12, 12' forming a second guide portion 1b, 1b '. In addition, another portion 1c, 1c 'of the outer surface 11, 11' forms an assembly surface with a watch movement, in particular with a blank 4, 4 '.

FIG. 5 illustrates a bearing 1 "according to a third variant of the first embodiment of the invention. This bearing has an elongated tubular geometry with the axis of the bearing A1", with an outside diameter De constant forming an outside surface 11 ", and comprising a bore 12", similarly to the first variant. It differs mainly from the first variant by a reduced height Ht. As a result, this 1 "level has a lower Ht / De form factor, of the order of 0.9.

This bearing 1 "is shown integrated into a watch movement 100" in Figure 5. It appears that its height Ht substantially corresponds to the thickness of a blank 4 ", so that it is driven into this blank to be integrated more or less substantially into the thickness of the blank. Its outer surface 11 "therefore substantially forms an assembly surface 1c" with the watch movement, more precisely with the blank 4 ".

On the other hand, a first end of the bore 12 "forms a first guide portion 1a", which allows the guiding of a first watch mobile 2 ". More precisely, this first guide portion 1a" cooperates with a pivot 21 "of the first watch mobile 2". Advantageously, the bearing 1 ″ comprises a stop surface 18 ″ arranged in a plane perpendicular to the axis of the bearing A1 ″ at the level of the first end of the bore 12 ″, which bears on the first watch mobile 2 ″. , thus participating in the axial retention with less play of the first watch mobile 2 ". The guiding of the first watch mobile is here rotational guiding. The guiding of the first watch mobile is also a guide in translation of the first watch mobile according to a clearance defining the axial range of the first watch mobile, typically a few hundredths of a millimeter.

Finally, a second end of the bore 12 "forms a second guide portion 1b", which allows the guiding of a second watch mobile 3 ". More precisely, this second guide portion 1b" cooperates with a pivot 31 "of the second mobile 3". Advantageously, the bearing 1 ″ comprises a stop surface 13 ″ arranged in a plane perpendicular to the axis of the bearing A1 ″ at the level of the second end of the bore 12 ″, which bears on the second watch mobile 3 ″. , thus participating in the axial retention with less play of the second watch mobile 3 ". The guiding of the second watch mobile is here a guide in rotation of the second watch mobile. The guiding of the second watch mobile is also a guide in translation of the second mobile according to a clearance defining the axial range of the second watch mobile, typically a few hundredths of a millimeter.

In this third variant embodiment, the bearing therefore has a first guide portion and a second guide portion which are both formed by a bore of the bearing.

FIG. 6 illustrates a bearing 1 * according to a second embodiment of the invention. This bearing 1 * has a structure similar to that of the bearing according to the second variant of the first embodiment, in which the widened portion 14 * is positioned substantially in the middle of the height Ht of the bearing 1 *. This enlarged portion 14 * is in the form of a cylindrical part of low height, of annular shape arranged around the bearing 1 *. Another portion of the outer surface 11 * of the bearing forms a first guide portion 1a *. This portion has the main external diameter De, by definition. It is in contact with the enlarged portion 14 *. It is therefore positioned approximately in the middle of the height Ht of the bearing 1 *. The outer surface of the bearing 1 * has two other portions, respectively at each of its ends. A first portion 16 * forms an assembly surface of the bearing 11 *. A second portion 17 * forms a fixing surface. Finally, as in the previous embodiment, the bearing 1 * comprises a central bore 12 *, arranged around the axis of the bearing A1 *. The Ht / De form factor of stage 1 * is of the order of 1.

The use of the bearing 1 * according to this second embodiment will now be explained in relation to FIG. 7, which illustrates this bearing 1 * integrated into a watch movement 100 *. In this arrangement, the first portion 16 * of its outer surface, which forms an assembly surface 1c *, is driven into a blank 4 *, in particular a plate, of the watch movement. An annular surface 15 * of the enlarged portion 14 * bears on a corresponding surface 41 * of the blank 4 *, forming a stop during the assembly of the bearing 1 *.

The first guide portion 1a * cooperates with a first mobile watchmaker 2 *. In this embodiment, this first watch mobile is a winding crown. More particularly, the first guide portion 1a * is housed in a bore 21 * of the winding crown.

On the other hand, the bore 12 * defines a second guide portion 1b *, which cooperates with a shaft 31 * of a second watch mobile 3 * crown. This second guide of the bearing 1 * has the particularity of being a guide in rotation combined with a guide in translation of the second watch mobile 3 * crown, the latter can for example be initiated by the actuation of a rod 5 * forming a cam surface 51 * cooperating with a longitudinal end 32 * of the shaft 31 *.

The bearing 1 * furthermore comprises a second portion 17 * of its outer surface provided to receive an axial retaining element 6 * of the first mobile watchmaker 2 *, such as a ring or a nut. The second portion 17 * may include a smooth surface, in particular for driving the axial retaining element 6 *. As a variant, the second portion 17 * can comprise a threaded surface, which can be provided to allow the screwing of the axial retaining element 6 *, which would be a nut.

In the embodiments described above, the bearing comprises a bore of cylindrical shape: advantageously, the diameter Dide this bore respects the interval 1 <De / Di≤ 5, or even 1.5≤ De / Di≤ 3. Such a bore is optional.

Figure 8illustrates a bearing 1 * 'according to a third embodiment. This bearing 1 * 'has a shape substantially identical to that of the first variant shown in FIG. 1, but not comprising a bore. It is thus similar to a tenon or to a pin of the bearing A1 * '. Its external surface 11 * 'has a main external diameter De constant over the entire height Ht, with the exception of the optional chamfers or roundings at its ends, already described with reference to FIG. 1. The form factor Ht / De is here of the order of 1.8.

FIG. 8 illustrates more precisely the bearing 1 * 'integrated within a watch movement 100 *'. It appears that the central portion of the outer surface 11 * 'of the bearing 1 *' forms an assembly surface 1c * 'in a blank 4 *', in particular a plate. The outer surface 11 * 'of the bearing 1 *' further comprises two guide portions 1a * ', 1b *' arranged on either side of the assembly surface 1c * '. The first guide portion 1a * 'cooperates with a first watch mobile 2 *'. It is more precisely inserted into a bore 21 * 'of the first watch mobile 2 *', in order to guide it. The second guide portion 1b * 'cooperates with a second watch mobile 3 *'. It is more precisely inserted into a bore 31 * 'of the second watch mobile 3 *', in order to guide it. In this embodiment, the bearing 1 * 'thus pivots first and second watchmaking wheels on either side of a blank 4 *'. These two watch mobiles are substantially identical, but could alternatively be different. In addition, in this embodiment, the two guide portions of the bearing 1 * 'are arranged on the outer surface of the bearing 1 *'.

Of course, the invention is not limited to the embodiments described. The bearing may comprise a part forming an assembly surface, in particular a driving surface, for its fixing in an opening of a blank, in particular a plate or a bridge. The bearing further comprises two guide portions. They each allow guidance in rotation and / or in translation. A lubricant may further be added to at least one guide portion of the bearing. In particular, this lubricant can be placed within a bore of the bearing, or more generally at the level of any mobile device, a pivot of which is pivoted in the bore of the bearing.

The bearing is made of ceramic, advantageously from a zirconia, in particular a yttriated zirconia, in particular a 3% yttriated zirconia, a monocrystalline alumina or an alumina-zirconia combination (ATZ).

The bearing can be manufactured by a method of manufacturing a bearing comprising the following steps: Pressing or injection of a precursor to form a green body; Sintering of the green body.

It emerges that the bearing obtained is in one piece. Advantageously, it comes in one piece.

The bearing according to the invention can be used for guiding the movement of any watch mobile. The invention also relates to a watch movement as such, comprising a bearing according to the invention. Such a watch movement is not limited to the examples described. Finally, the invention also relates to a timepiece, such as a watch, in particular a wristwatch, which incorporates one or more bearings according to the invention.

Claims (15)

1. Bearing (1, 1 ', 1' '; 1 *; 1 *') for a watch movement, characterized in that it is in a single piece and ceramic form and in that it comprises a first portion of guide (1a, 1a ', 1a' '; 1a *, 1a *') suitable for guiding a first watchmaking mobile (2, 2 ', 2' '; 2 *, 2 *') and a second guide portion (1b, 1b ', 1b' '; 1b *, 1b *') suitable for guiding a second watch mobile (3, 3 ', 3' '; 3 *, 3 *'). 2. Bearing for a watch movement according to the preceding claim, characterized in that it has a substantially tubular shape arranged around an axis of the bearing (A1, A1 ', A1' '; A1 *, A1 *') and having a height Ht along this axis of the bearing, and comprising a main outer diameter De in a plane perpendicular to this axis of the bearing, this main outer diameter De corresponding in particular to the diameter at a guide portion arranged on an outer surface of the bearing and / or corresponding to the portion of constant outer diameter of greatest height of the bearing, and characterized in that the bearing has a shape respecting the interval 0.8≤ Ht / De≤ 5, or even 1≤ Ht / De≤ 3, or even 1.2 ≤ Ht / De≤ 2.4 3. Bearing for a watch movement according to the preceding claim, characterized in that it comprises a bore (12, 12 ', 12' '; 12 *) of cylindrical shape, in particular of diameter Direspecting the interval 1 <De / Di≤ 5, or even 1.5≤ De / Di≤ 3. 4. Bearing for a watch movement according to one of the preceding claims, characterized in that: To. The bearing has an outer surface (11 * ') a first part of which forms said first guide portion (1a *') and a second part of which forms said second guide portion (1b * '); Where b. The bearing has a bore (12 '') a first part of which forms said first guide portion (1a '') and a second part of which forms said second guide portion (1b ''); Where vs. The bearing has an outer surface (11, 11 ', 11 *) and a bore (12, 12', 12 *), at least part of the outer surface forming said first guide portion (1a, 1a ', 1a *) ) and at least part of the bore forming said second guide portion (1b, 1b ', 1b *). 5. Bearing for a watch movement according to one of the preceding claims, characterized in that it comprises an outer surface comprising: - at least a portion of cylindrical and smooth shape forming a guide portion of the bearing; and or - at least one part forming an assembly surface (1c, 1c ', 1c' '; 1c *, 1c *'), in particular for driving, of the bearing with a blank, in particular a plate or a bridge; and or - at least part of the threaded surface. 6. Bearing for a watch movement according to one of the preceding claims, characterized in that it has a substantially tubular shape arranged around an axis of the bearing and in that it has a surface in a plane perpendicular to the axis. of the bearing forming a stop surface (13, 13 ', 15', 13 ''; 13 *, 15 *) for the axial retention of a watch mobile and / or for the axial positioning of the bearing and / or, said surface of abutment being in particular formed by a surface (14 ') arranged on one end of the bearing and / or being formed by an enlarged portion (14 *) of larger outside diameter of the bearing. 7. Bearing for a watch movement according to one of the preceding claims, characterized in that it has a tubular shape, the outer surface of the bearing (11; 11 '', 11 * ') is cylindrical with constant diameter over substantially the entire length. landing height. 8. Bearing for a watch movement according to one of the preceding claims, characterized in that it is in one piece. 9. Bearing for a watch movement according to one of the preceding claims, characterized in that it is made of ceramic from a zirconia, in particular a yttriated zirconia, in particular a 3% yttriated zirconia, a monocrystalline alumina or an alumina-zirconia combination ( ATZ). 10. Watch movement, characterized in that it comprises a bearing according to one of the preceding claims. 11. Watch movement according to the preceding claim, characterized in that the first guide portion and the second guide portion of the bearing each allow guidance in rotation and / or in translation of a respective watch mobile of the watch movement. 12. Watch movement according to claim 10 or 11, characterized in that it comprises a first timepiece mobile (2, 2 ') and a second clock mobile (3, 3') of a movement finishing chain. base (100, 100 ') comprising a pivot (31, 31'), in particular an average mobile, and in that the bearing comprises an outer surface (11, 11 ') and a bore (12, 12') , at least part of the outer surface (11, 11 ') of the bearing (1, 1') forming said first guide portion (1a, 1a ') and at least part of the bore (12, 12') forming said second guide portion (1b, 1b '), the first guide portion of the bearing cooperating with the first timepiece mobile (2, 2') and the second guide surface cooperating with the pivot (31, 31 ') of the second watch mobile (3, 3 '). 13. Watch movement according to claim 10 or 11, characterized in that it comprises a first mobile clock (2 '') which is a winding crown comprising a bore (21 '') and a second mobile clock (3 '') crown comprising a shaft (31 ''), and in that the bearing (1 '') comprises an outer surface (11 '') and a bore (12 ''), at least part of the outer surface (11 '') of the bearing forming said first guide portion (1a '') and at least part of the bore (12 '') forming said second guide portion (1b ''), the first guide portion (1a ' ') of the bearing cooperating with the bore (21' ') of the winding crown and the second guide surface (1b' ') cooperating with the shaft (31' ') of the second watch mobile (3' ') of Crown. 14. Watch movement according to one of claims 10 to 13, characterized in that the bearing comprises an assembly surface (1c, 1c ', 1c' '; 1c *, 1c *') by which it is fixed in a blank (4, 4 ', 4' '; 4 *, 4 *'), in particular a plate or a bridge, of the watch movement. 15. Timepiece, characterized in that it comprises at least one bearing according to one of claims 1 to 9 or a timepiece movement according to one of claims 10 to 14.