CH714318A2 - Clockwork motor member delivering a substantially constant force. - Google Patents

Abstract

The invention relates to a clockwork motor unit (1) comprising a support (7), an elastic member (6) and a drive element (5), characterized in that said drive element (5) is suitable to be moved and guided in translation relative to the support (7) by said elastic member (6), this translation allowing the delivery of a force to a watch mechanism (2, 3). The invention also relates to a clock mechanism comprising such a motor member, a timepiece, such as a wristwatch, comprising such a clock mechanism and a use of such a motor member as an energy source for a mechanism independent watchmaker of the finishing gear.

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a motor unit for watchmaking, in particular a motor element with a substantially constant force.

The watch motor member according to the invention may be either a motor of a watch movement arranged to drive a finishing train, or a motor member of an additional mechanism such as a striking mechanism or a chronograph mechanism.

[0003] In watchmaking, a barrel has traditionally been used as the driving mechanism of a watchmaking mechanism. A barrel is an assembly of at least three elements: a barrel spring consisting of a spiral spring blade, a barrel drum serving as a housing for said spring, said drum being freely rotatable on a barrel shaft (pivoting shaft between bridge and platen), and a barrel cover for closing the barrel drum, said lid also being freely rotatable on the barrel shaft. Out of the barrel drum, the blade comes out in the shape of an inverted S. The unwinding of the blade, wound against the diameter of the bung of the barrel shaft and seeking to return to its original shape, produces the energy necessary for the operation of the clock mechanism.

A disadvantage of such a motor member is that its performance is affected by the friction of the turns of the spiral spring against each other and against the inside of the barrel drum, during unwinding of the barrel. To reduce this friction, it is usual to lubricate the turns of the spring and deposit an anti-friction coating in the drum. Despite this, such a drive member suffers energy losses of about 15% due to friction.

Another disadvantage of such a motor member is that the manufacture and shaping of the spring blade that it contains, its S shape returned to its spiral shape, must strongly take into account the limit of elasticity of the material constituting the spring blade. In addition, the introduction of the spiral spring housed in the barrel drum is based on a long experience of the watchmaker and requires many handling steps. It is also an assembly of several elements.

Such a motor unit is expensive and difficult to manufacture.

In addition, the moment of force delivered by such a motor member is not constant, which affects the isochronism of the clock mechanism. To alleviate this problem, some watch movements use an intermediate spiral spring between the motor member and the exhaust. A disadvantage of this solution is that it complicates the movement by introducing an additional element.

The object of the present invention is to provide an alternating drive member to the barrel comprising a spiral spring traditionally used which allows to overcome, at least in part, the aforementioned drawbacks.

The invention proposes for this purpose a clockwork motor member comprising a support, an elastic member and a driving element, characterized in that said drive element is able to be set in motion and guided in translation. relative to the support by said elastic member, this translation allowing the delivery of a force to a watch mechanism.

The present invention also proposes a clock mechanism comprising such a clock motor unit, said mechanism typically comprising a winding mechanism arranged to arm the drive member and a gear train arranged to be driven by the motor member, as well as a timepiece such as a wristwatch or a pocket watch comprising such a watch mechanism.

The timepiece according to the invention preferably comprises a watch case and a winding mechanism of said motor member, said winding mechanism being operable from outside the watch case.

Finally, the present invention provides the use of such a motor member as a power source for a clock mechanism independent of the work train.

The clock motor member according to the invention allows the delivery of a force by a rectilinear displacement in translation of a drive element. This cancels the need for turns as well as all the problems associated with them.

The motor member according to the invention also has the advantage of significantly improving the efficiency (average energy loss of between 0 and 1% only against 15% for a traditional spiral spring barrel). Indeed, the elastic member that composes it does not undergo friction.

In addition, the driving member according to the invention has the advantage of delivering a substantially constant force, thus improving the isochronism of the watch movement with which it is associated, without requiring an intermediate spring between the motor member and the 'exhaust.

Other features and advantages of the present invention will appear on reading the following detailed description with reference to the accompanying drawings, in which: FIG. 1 is a perspective view from above of a part of a watch mechanism incorporating a clockwork motor member according to a particular embodiment of the invention; fig. 2 is a perspective view from below of the mechanism shown in FIG. 1; figs. 3a and 3b are diagrammatic representations in plan view of the motor unit shown in FIG. 1 isolated, respectively at rest and pre-armed; fig. 4 (curve Co) is a graphical representation of the force exerted in the driving member of FIGS. 3a and 3b according to its state of arming; fig. 5 shows graphically the elastic return force exerted by a buckling blade belonging to the motor member shown in FIGS. 3a and 3b (curve C-ι) as well as the maximum stress of Von Mises exerted on this blade (curve C2); fig. 6 shows graphically the elastic restoring force exerted by a set of flexural blades belonging to the motor member shown in FIGS. 3a and 3b (curve C3) as well as the maximum stress of Von Mises exerted on this set of blades (curve C4); fig. 7 is a representation in a single graph of the curves Co, C-ι and C3.

Figs. 1 and 2 show a part of a watchmaking mechanism, more precisely a watch movement, comprising a clockwork motor unit 1 according to a particular embodiment of the invention.

This watch movement further comprises, in particular, a finishing gear 2 and an exhaust 3 as illustrated in FIGS. 1 and 2. Advantageously, said watch movement also comprises a winding mechanism (not shown).

The winding mechanism typically comprises a winding stem and a winding gear. In a variant, it could be of automatic type, oscillating weight.

The motor member 1 illustrated in FIGS. 1 and 2 is typically monolithic. It comprises a gear rack 5 toothed, moving in translation and a rigid support 7.

The motor member 1 also comprises an elastic member 6 connecting said rack 5 to said support 7. The support 7 is in one part in the motor member 1 shown in FIG. 1 but could comprise several fixed parts relative to each other, for example several parts fixed on the same frame.

The elastic member 6 typically comprises: - an elastic blade 6a working in buckling, said blade 6a being interrupted in its central part by the rack 5 and having its two ends joined to said support 7; - A pair of resilient junction blades 6b working in flexion, one end of each blade of said pair being connected to the rack 5 and extending from the rack 5 to the support 7; and two pairs of parallel elastic strips 6c, working in flexion and connecting the pair of elastic joining strips 6b to the support 7.

The support 7 is fixedly mounted relative to the movement, for example in the plate of the movement. It advantageously comprises holes 8 for receiving fastening means such as screws and / or pins for fixing, typically in the plate of the movement.

During operation of the drive member 1, the rack 5 is movable. It is guided in translation by the elastic member 6 and moves along a straight line (d), as illustrated in FIGS. 3a and 3b. In the example illustrated in these figures, the assembly comprising the elastic member 6 and the rack 5 is symmetrical with respect to this line (d).

To deliver energy, the motor unit 1 must be armed. The armature of the motor unit 1 is effected by translation of the rack 5 along the line (d) in the direction causing a compression force on the blades 6a and their buckling, that is to say in the direction of the support 7 (direction of arming). This movement causes a deformation of the elastic member 6 which accumulates energy. For purposes of simplification, the elastic blade 6a of the motor member 1 as shown in FIGS. 1 and 2 is shown right. She is actually soaring. When it is armed, the motor unit 1 is able to deliver the stored energy by translation of its rack 5 along the line (d) in the opposite direction to the winding direction.

Advantageously, the winding system (not shown) makes it possible to arm the motor member 1 as previously described.

Advantageously, the winding system generates, in the active position, the clutch between the motor member 1 and the work train 2 and allows, in this position, to arm the motor member 1. When in position inactive, the clutch between the motor unit 1 and the work train 2 is restored. In this inactive position, it no longer makes it possible to arm the motor unit 1.

Such a winding system including a disengagement / clutch system may typically comprise a wheel comprising a wheel and a pinion, said pinion being kinematically connected to the rack 5 of the drive member 1, said wheel being kinematically connected to the gear train finishing 2, said wheel and pinion being integral in rotation when said pinion is rotated in a first direction, this first direction corresponding to the direction in which said pinion rotates when it receives energy from the drive member, but not integral in rotation when said pinion is rotated in a second direction, opposite the first, that is to say when the pinion makes it possible to raise the motor member 1.

In the embodiment illustrated in FIG. 1, the rack 5 comprises a toothing 9 for connection with the work train 2. The toothing 9 of the rack 5 typically meshes with a first pinion 10a of the work train 2 and is thus able to set it in motion.

The watch movement shown in FIGS. 1 and 2 comprises the first pinion 10a, said pinion 10a pivoting about an axis 100 (virtual), meshing with the toothing 9 of the rack 5 and being kinematically connected to the escape wheel 3a of the exhaust 3.

Advantageously, the watch movement shown in FIGS. 1 and 2 comprises a first mobile 10 pivoting about the axis 100, said first mobile 10 comprising said first pinion 10a and a first wheel 10b which is coaxial and rotationally integral therewith. More preferably, the escape wheel 3a is coaxial and integral with an escape pinion 3b meshing with a second wheel 11b of a second mobile 11 pivoting about an axis 200 (virtual), said second mobile 11 also comprising a second pinion 11a coaxial and rotationally fixed to the second wheel 11b and meshing with the first wheel 10b of said first mobile 10.

When the motor member 1 of FIG. 1 is armed, it disarms by exerting a force F tending to move in translation its rack 5 along the line (d) in the direction of the arrow F of FIG. 1 (opposite direction to arming). The teeth 9 of the rack 5 meshing with the first pinion 10a of the first mobile 10, the first pinion 10a is rotated in the anti-clockwise sense of FIG. 1. The first wheel 10b which is secured to it in rotation is also rotated in the counter-clockwise direction and in turn causes the clockwise rotation of the second pinion 11a and the second wheel 11b. Finally the second wheel 11b rotates the exhaust pinion 3b and the escape wheel 3a which cooperates with the exhaust anchor 3c in the anti-clockwise direction of FIG. 1.

In the absence of a device limiting the movement of its rack 5, the drive member 1 disarms until its elastic member 6 is at rest, that is to say in the position in which all its elastic blades 6a, 6b, 6c are at rest (exert no elastic restoring force). Once this position is reached, the motor unit 1 no longer delivers energy and must be re-armed to supply energy. In the illustrated example, when the member 6 is in the rest position (see Fig. 3a) the straight line (d) is substantially parallel to the blades 6b and substantially equidistant from each of these blades.

Advantageously, the set of elastic blades 6a, 6b, 6c of the elastic member 6 is designed to exert in the motor member 1 a substantially constant elastic return force F over a predetermined range of positions of the rack 5 relative to the support 7 along the straight line (d), that is to say an elastic restoring force F not varying by more than 1% on said predetermined range of positions.

For the understanding of the invention, the behavior of the drive member 1, considered in isolation, that is to say free of any interaction with the work train 2 or the winding train, is described below. below.

The single drive member 1 shown schematically in FIG. 3a can be armed by translation of its rack 5 along the line (d) in its arming direction by a distance A. The position in which Δ = 0 corresponds to the rest position of the elastic member 6 of the driving member 1. FIG. 3a represents the drive member 1 isolated in said rest position. The value of A increases as the rack 5 approaches the holder 7 (downward in Fig. 3a).

In general, when the rack 5 is in the position in which the associated value of A is equal to x mm, it is said that the drive member 1 is armed x mm.

As indicated above, during the arming, the resilient member 6 is deformed to exert, in the engine 1 armed member, a restoring force F (A) in the opposite direction to the winding direction, this force depending on the position Δ of the rack 5 and tending to return the drive member 1 in its rest state, that is to say in our example to move the rack 5 away from the support 7. FIG. 3b represents the drive member 1 isolated after arming. The arrow F shown in FIG. 3b illustrates the return force F (A), which tends to return the drive member 1 in its rest state.

The motor member 1 shown in Figs. 3a and 3b corresponds to a particular motor unit 1 made by the Applicant whose dimensions are, when in the idle state, those indicated in Table 1 below.

Table 1: Dimensions of the particular motor unit 1 made by the applicant, isolated and in the idle state [0040] Order No. Size Unit (Fig. 3a) a Length 19 mm b Space between the bending blades 6c 1.78 mm c Space between the blade 6a and the blade 4.75mm 6c lower d Width 7mm E Opening space E of the element 1.78mm motor 1 at rest f Arrow of the blade 6a 1.8mm g Thickness blade 6a 100μm h Thickness blades 6b and 6c 118.65μm - 1.5mm blade height [0041] The sizes g: "blade thickness 6a" and h: "blade thickness 6b and 6c" are measured in the plane in which is represented the motor unit 1 while the size " height "is measured perpendicular to this plane.

The elastic junction blades 6b working in flexion give a degree of freedom to the resilient blades 6c which can move away, thus increasing the value of the distance E (Figs 3a and 3b). This degree of freedom is necessary for the proper functioning of the mechanism, however, it could be obtained by any other suitable means. The value of E depends on the state of arming of the motor unit 1. When the motor unit 1 is at rest, the opening space E has a value equal to 1.78 mm.

With reference to FIG. 4, ie at the position of the rack 5 of the motor unit 1 isolated along the straight line (d), as defined above; fig. 4 represents the evolution F (A) of the force F exerted by the rack 5 in the direction of the arrow F (see FIG 3b), this force being the resultant of the elastic restoring forces exerted by the elastic blades 6a, 6b and 6c of the elastic member 6. The values of the force F (A), for each position A, correspond to the force required to maintain the rack 5 in the corresponding position A. These values are derived from a simulation of the evolution of the force of the particular drive member 1 isolated made by the applicant according to the position A of its rack 5.

As can be seen in the graph of FIG. 4 (Co curve), this force follows an evolution in several phases: - for a position A between 0 and a first value, the force F increases rapidly with the position A; this phase corresponds to an arming phase; - Beyond this first value, the motor member 1 is in a stable phase. Indeed, between this first value and a second value, the force F is substantially constant with respect to the position A (the curve Co has a plateau). beyond this second value, the force F is no longer substantially constant and increases again until reaching a limit value F | imite, for a displacement A = Δ | Μθ. This F | imite value depends on the properties of the material in which the motor member 1 is made and is reached when the elastic member 6 undergoes the maximum stress that it can support.

The particular isolated motor member 1 studied in FIG. 4 is made of steel sulem H1 CK101 (non-alloy structural steel) but any suitable material can be used. For example materials such as silicon typically coated with silicon oxide, Nivaflex® 45/18 (cobalt-based alloy, nickel and chromium), polymers, composites (carbon or Kevlar® (poly (p-phenyleneterephthalamide) or PPD-T))) or metal glasses are also suitable and allow to obtain drive members delivering a substantially constant force on the same ranges of positions but with different intensities.

The range of positions for the delivery of a substantially constant force being a constant related to the shape of the elastic blades, the maximum stress experienced by the elastic blades must be less than or equal to the elastic limit (corresponding F | irnite ) of the material in which they are made. When using, it will be important not to exceed Δ | Μθ to avoid laminating or breaking the blades.

The various usable materials mentioned above (apart from polymers whose elastic limit is low without the composite appearance), to the dimensions considered, can undergo, without risk of plastic deformation or rupture, stresses (of Von Mises or main for ceramics) up to 2100 MPa.

The isolated drive member 1 having an evolution of the force F (A) as shown in FIG. 4 differs from conventional elastic structures. Its properties are based on the combination of different types of elastic blades whose properties are specifically chosen as well as on their arrangement allowing the addition of their elastic return forces.

Curve C-ι of FIG. 5 illustrates (in N) the elastic return force Ff | amb associated with the elastic blade 6a working in buckling as a function of the position Δ of the rack 5 of the motor member 1 relative to the support 7, along the right (d). Note that for a certain range of values of A extending, in this particular motor unit 1, from about 0.015 mm to about 2.4 mm, the curve Ci associated with the blade 6a is substantially straight, with a control coefficient of about equal to -2.75 (N / mm). Indeed, a linear regression was carried out and gives a right equation y = -2.7523 X + 4.9889 with R2 = 0.9991. The elastic blade 6a of the motor member 1 thus has, in this range of values at least, a negative stiffness.

The capacity of the elastic blade 6a to work in buckling allows it, when considered in isolation, to behave as a bistable or at least to have a negative linear stiffness over a range of given positions. The adjustment of the ratio between the arrow f of the blade 6a at rest and its thickness as well as the adjustment of its length and height make it possible to modulate the linearity of the right portion on which the blade 6a has a negative stiffness.

The elastic blade 6a is here preformed right and working buckling under the effect of its arming. It could however be preformed flambé, that is to say machined with a flamed shape. Yet another possibility would be the use of a straight preformed elastic blade 6a and then compressed during assembly of the motor unit 1.

C2 curve of this same fig. 5 illustrates, for its part, the maximum stress of Von Mises (in MPa) exerted on the blade 6a as a function of the position Δ. It should be noted that the Von Mises stress exerted on the blade 6a is less than 2100 MPa over the entire range of positions A ranging from 0.015 mm to 2.4 mm for which the curve Ci is substantially straight.

The curve C3 of FIG. 6 illustrates, the elastic return force Ffiexion associated with all the blades 6b, 6c working in flexion as a function of the position Δ of the rack 5 of the motor member 1 relative to its support 7, along the right (d). As is the case for any type of spring working in bending, the curve C3 associated with the set of blades 6b and 6c is a straight line over a given range of values. The blades 6b, 6c have a positive stiffness and are chosen so that the stiffness of the association of the blades 6b, 6c in flexion is approximately equal to 2.75 (N / mm), that is to say so that the coefficient of the straight line Flexion (A) is approximately equal to 2.75 (N / mm).

Thus, the directional coefficients of the straight line portions associated with the C-ι (Ff | amb (A)) and C3 (F | eXiOn (A)) curves are opposite. The curve C3 flexes slightly for values of A exceeding 2.6 mm, and can therefore be considered as a straight line with a coefficient of about 2.75 for values of A ranging between 0 and 2.6 mm. A linear regression was performed and gives a right equation y = 2.7511 x + 0.0045 with R2 = 1.

The curve C4 of this same fig. 6 illustrates, as for it, the maximum stress of Von Mises (in MPa) exerted on all the blades 6b and 6c working in flexion as a function of the position Δ. It should be noted that the Von Mises stress exerted on this set of blades 6b, 6c is less than 2100 MPa for a range of positions Δ ranging from mm to 2.1mm. Beyond 2.1mm, the stress on the blade assembly 6b, 6c exceeds 2100 MPa. That is to say that for positions A corresponding to an armature of more than 2.1mm, the set of blades 6b and 6c is subject to a risk of plastic deformation or rupture.

The arrangement of the blades 6a, 6b and 6c of the drive member 1 is such that the curve Co corresponds to the sum of the curves Ci and C3 of Figs. 5 and 6, as illustrated in FIG. 7. Thus, in so far as the coefficients of the straight portions associated with the curves C! and C3 are opposed, the combination of the negative stiffness obtained by means of the blade 6a working in buckling with the positive stiffness obtained by means of the blades 6b, 6c working in bending, makes it possible to obtain a substantially zero stiffness , that is to say a substantially constant force F, as illustrated in fiq. 4 and 7.

The set of blades of the elastic member 6 of the motor member 1 is arranged to exert a force F (A) substantially constant over a range of positions [Δπίη, Amax] of its rack 5 relative to its support 7.

We will distinguish the theoretical range [Δπίη, Amax] ([Aminjhéo, Amaxthéo]), corresponding to the range of positions of the rack 5 of the drive member 1 relative to its support 7 in which the motor member 1 is potentially capable of delivering a substantially constant force of constant value F, regardless of any risk of rupture and / or plastic deformation, and the range [Amin, Amax] of use ([Amin.use, Amax utilization]) corresponding to the range of positions of the rack 5 of the motor member 1 relative to its support 7 in which the motor member 1 is adapted to deliver a substantially constant force Festante value without risk of plastic deformation or rupture of one elastic blades of its elastic member.

The range of positions ([Aminjhéo, Amax_théo]) corresponds to the range of intersection of the position ranges in which the curves C-ι and C3 are straight. This range of positions ranges from A = 0.015 mm to A = 2.4 mm in the illustrated example.

The range ([Ammn_utiüsation, Amax utiiisation]), necessarily included in the range ([Amjn_théo, Amax_théo]), takes into account the data curves C2 and C4. It is restricted to a range of positions from Δ = 0.015 mm to Δ = 2.1mm. Indeed, curves C2 and C4 indicate that for values of A greater than 2.1 mm, the stress of Von Mises exceeds 2100 MPa, that is to say that for values of A greater than Amax_utiiiSation 2.1 mm, the elastic member 6 of the motor member 1 could plastic deformation or rupture. It should be noted however that, by changing the material used for the production of the drive member, the limit beyond which the blades present a risk of plastic deformation or rupture could be greater than 2100 MPa.

The constant force F corresponds to the value of the force F exerted between the Amin and Amax positions considered (plateau value). This force is worth about 5N in the illustrated example.

When armed with an Aarm value of at least Amin_utiiiSation = Amin_théo = 0.015 mm not exceeding Amax_utiiiSation (2.1 mm in our example), the drive member 1 studied disarms by exerting a force F substantially constant by translation of its rack 5 along the straight line (d) in the opposite direction to the winding direction, over a range of positions of its rack 5 relative to its support 7 from said armature value Aarm up to a value corresponding to Δ = Amin. If no stop prevents it from disarming completely the motor unit 1 will disarm until A = 0, that is to say to its rest position. The force F then exerted between the positions A = Amin and Δ = 0 will be of decreasing intensity.

If the drive member 1 is armed with an A value greater than Amax use but less than "theoretical" Amax, it is possible that it is broken or plastically deformed, which would change its behavior. If this were not the case, it would behave as in the previous case.

Finally, if the motor member 1 is armed with a value A greater than theoretical Amax, if it does not see the blades of its elastic member 6 to break or deform plastically, it will exert a force F d ' firstly, greater than the force F constant over the range of positions between Aarm and the theoretical axis, then a substantially constant force of approximately equal value to the magnitude of the position range [theoretical Amax, Amin "theoretical], then finally, if no limit stop prevents it from disarming completely, it will disarm until it returns to its rest position (Δ = 0). The force then exerted between the positions A = theoretical Amax and Δ = 0 will be of decreasing intensity.

Advantageously, the clock mechanism incorporating the drive member 1 or the motor member 1 itself may comprise stops to maintain said motor member 1 in the range of positions [Aminjhéo, AmaxJhéo] of its rack 5 relative to its support 7 allowing the delivery of a substantially constant force. Preferably, said stops make it possible to maintain said motor member 1 in the range of positions [Amin use, Amax use] of its rack 5 relative to its support 7 allowing the delivery of a substantially constant force and avoiding any risk of rupture or of plastic deformation of the blades of its elastic member 6.

In a variant of the invention, the toothing 9 could be carried by a drive element other than a rack and could cooperate with one of the other toothed compounds that a pinion, for example with a toothed wheel or a rake. In addition, the rack 5 could be replaced for example by a toothed drive rod cooperating with a toothless wheel by adhesion or friction or by any other drive element 5 able to deliver the restoring force that it receives from the elastic member 6 to a mechanism.

As indicated above, the motor member 1 can be made of any suitable material. As indicated above, the material chosen for producing the elastic blades of the drive member will impact the limit of plastic deformation or rupture.

The motor member 1 according to the invention may be manufactured by machining, especially in the case where it is made of metal or an alloy such as Nivaflex®, by DRIE etching in the case of silicon for example, or still by molding, especially in the case where it is made of plastic or metal glass.

It will be clear to those skilled in the art that the present invention is in no way limited to the embodiment shown above and illustrated in the figures.

It is for example very conceivable to achieve a motor member whose elastic blades component of the elastic member are of different shapes from those shown in the figures or are arranged differently with respect to the embodiment shown in the figures. In particular, the combination of at least one elastic blade working in buckling and at least one elastic blade working in bending can allow to obtain a substantially constant force, even if they are arranged differently with respect to embodiment shown in the figures.

As indicated above, the support of the motor member according to the invention is typically fixed on the plate of the movement. Alternatively, if said plate is made of a high elasticity material, it is conceivable to produce a monobloc device comprising the plate and the motor member according to the invention.

The value of the force reached in the stable phase of the drive member can typically be adjusted by changing the thickness of the elastic blades that comprises the elastic member and / or the material used to achieve them.

The motor member 1 according to the invention may allow the setting of a gear train 3 but is advantageously used for setting in motion an additional independent mechanism such as a striking mechanism or chronograph . The motor unit 1 according to the invention can also be used as an independent energy source in a watch mechanism as described in the European patent application filed under number 17 166 832.0.

In addition to the many advantages mentioned above, particularly related to its structure without turns, the motor member according to the invention has the advantage of delivering a substantially constant force and thus improves the isochronism of the watch movement to which it is associated, without complicating.

Claims (15)

claims 1. Clockwork motor unit (1) comprising a support (7), an elastic member (6) and a driving element (5), characterized in that said drive element (5) is able to be set in motion and guided in translation relative to the support (7) by said elastic member (6), this translation allowing the delivery of a force to a watch mechanism. 2. Engine member (1) according to claim 1, characterized in that it is monolithic. 3. Engine member (1) according to one of the preceding claims, characterized in that said elastic member (6) comprises at least one elastic blade (6a) working in buckling and at least one elastic blade (6b, 6c) working in bending. Motor unit (1) according to one of the preceding claims, characterized in that the elastic member (6) is designed to exert a substantially constant elastic return force over a predetermined range of positions of the drive element. (5) relative to the support (7). 5. Engine member (1) according to one of the preceding claims, characterized in that said predetermined range of positions of the drive element (5) relative to the support (7) includes all the positions that can take the driving element (5). Motor unit (1) according to one of the preceding claims, characterized in that the drive element (5) comprises a toothed rack whose teeth (9) is intended to cooperate with the toothing of a component such that a toothed gear, toothed gear, rake or other toothed component or in that the drive element (5) comprises a toothless element intended to cooperate with a non-toothed friction component. 7. Engine member (1) according to one of the preceding claims, characterized in that said drive element (5) comprises a toothing (9), the toothing (9) for the delivery of said force to said clock mechanism (2 , 3). 8. Engine member (1) according to one of the preceding claims, characterized in that it is armed by translation of its drive element (5) in the same direction and in the opposite direction to the translation it describes. when he delivers said force. 9. Clock mechanism characterized in that it comprises a motor member (1) according to any one of claims 1 to 8. 10. Clock mechanism according to the preceding claim, characterized in that it comprises stops to maintain the motor member (1) in a range of positions of its drive member (5) relative to its support (7) allowing the delivery of a substantially constant force. 11. Watchmaking mechanism according to one of claims 9 or 10, characterized in that it comprises a winding mechanism arranged to arm the drive member (1) and a train (2) arranged to be driven by the drive member. (1). 12. Timepiece, such as a wristwatch, comprising a watch mechanism according to one of claims 9 to 11. 13. Timepiece according to claim 12, characterized in that it comprises a watch case and a winding mechanism of said motor member, said winding mechanism being operable from outside the watch case. 14. Use of a drive member according to one of claims 1 to 8 as an energy source for a clock mechanism independent of the work train. 15. Use according to claim 14, characterized in that said mechanism as energy source for a clock mechanism independent of the work train comprises a chronograph or striking mechanism.