Timepiece movement comprising a generator

Abstract

This invention relates to a watch movement including a generator. The electromechanical watch movement (2) includes pointer-type time display devices (25, 26) and is provided with: at least one electromechanical motor for driving at least one indicator of the pointer-type time display; and a generator (20) including a rotor (20A) and associated with a balance wheel (22) coaxial with the time display device. The watch movement includes a first wheel (40) provided with a shaft (36) coaxial with the indicator, which in a primary embodiment is guided to rotate by a fixed cylindrical tube (30). At least one gear shaft (26) of the time display device is rotatably mounted around the fixed cylindrical tube (30). The first wheel (40) meshes with the rotor of the generator and is fixedly connected to the balance wheel on a side opposite the pointer-type time display, such that the balance wheel can rotate the rotor of the generator via the first wheel.

Description

Technical Field

[0001] The present invention relates to a watch movement having an analog time display and including at least one part that consumes current, the watch movement further including a generator / micro-generator (hereinafter referred to as "generator") capable of generating electrical energy so as to supply power to the current-consuming part. Background Technology

[0002] Document EP 0 998 009 describes a watch movement equipped with a generator in its first embodiment, the rotor of which is directly coupled to a balance wheel. The balance wheel is fastened by screws to a wheel meshing with the rotor of the generator. For example, it is expected that the gear train between the balance wheel and the rotor has a multiplication operation of 100 times the rotational speed. No technical explanation is given regarding the arrangement of the balance wheel in the watch movement. Documents US 5,822,278 and US 6,320,822 propose a similar arrangement for the generator and indicate that the pointer display is driven by a separate motor, which is shown as independent of the assembly formed by the generator and the balance wheel, without any specific disclosure regarding the mounting of the balance wheel in the watch movement. Document EP 0 326 312, in the name of the same holder, in its... Figure 2 (a) shows, in cross-section, the technical teachings regarding the arrangement of the "generator and pendulum wheel assembly associated with the first gear train" and the "electric motor combined with the second gear train and the pointer-type display with three coaxial pointers". According to these teachings, the second hand pivots downward in a clamp 12. Below this clamp is another clamp 13, in which ball bearings are arranged. The pendulum wheel is fastened to the central portion of the ball bearings by screws, and this central portion is rotatable. To transmit torque to the rotor of the generator, a central wheel integrated with the pendulum wheel is arranged between clamp 13 and the disc of the pendulum wheel, and this central wheel meshes with a pinion arranged on the same horizontal plane. This arrangement is bulky and complex, featuring a stack of several wheels, a lower bearing for the second hand wheel arranged in an intermediate clamp, ball bearings arranged in the lower clamp, and a separate central wheel between the lower clamp and the pendulum wheel, enabling torque transmission to the generator via an eccentric wheel assembly. Summary of the Invention

[0003] The present invention aims to provide a motor mechanism incorporating a generator that is smaller, less complex, and cheaper than the same type of mechanism described in the aforementioned document EP 0 326 312. In particular, it is desirable that the motor mechanism according to the present invention requires fewer modifications and does not increase the height compared to conventional motor mechanisms, which have a central pendulum and a pointer-type time display with three pointers also located at the center.

[0004] Therefore, the present invention relates to an electromechanical watch movement comprising an analog time display device and equipped with: at least one electromechanical motor for driving at least one indicator of the analog display; and a generator including a rotor and associated with a balance wheel, the balance wheel being coaxial with the time display device. The watch movement includes a first wheel having a shaft coaxial with the indicator, the shaft being guided to rotate by a canon or a fixed cylindrical tube, the canon carrying the indicator and integrally connected to a second wheel, the second wheel being engaged with the electromechanical motor, the canon being rotatably mounted around the fixed cylindrical tube. According to the invention, the first wheel is engaged with the rotor of the generator, the first wheel being fixedly connected to the balance wheel on a side opposite the analog display, such that the balance wheel can rotate the rotor of the generator via the first wheel.

[0005] Due to the features of this invention, a central wheel, fastened to the balance wheel hammer, can be formed in a manner similar to the second wheel to rotate the generator rotor via a first gear train. This second wheel has an axle guided by a fixed cylindrical tube or by the gear shaft itself on the side of the pointer display. The gear shaft of the minute wheel is rotatably mounted around the fixed cylindrical tube. This arrangement allows for a reduction in the size of the watch movement, particularly its height / thickness. Preferably, the pointer display is configured without a second indicator coaxial with the minute indicator. However, in certain embodiments, which will not be described in detail later, a second indicator coaxial with the minute indicator is provided. In the latter case, the second indicator is mounted on the gear shaft of the second wheel, the axle of which is rotatably arranged inside the gear shaft of the second wheel, while the gear shaft of the minute wheel is mounted around the gear shaft of the second wheel.

[0006] According to the invention, a further proposed method is to use an electromechanical type motor module comprising at least: a first motor formed of a permanent magnet rotor and a stator, the stator having at least one coil and associated with a first wheel having a shaft; and a second motor associated with at least a second wheel having a gear shaft intended to carry a minute indicator of a pointer-type time display, the shaft being guided to rotate by a fixed cylindrical tube or by the gear shaft itself, and intended to carry a second indicator or second counter in the motor module, to form an electromechanical module with the gear shaft mounted around the fixed cylindrical tube, the electromechanical module comprising, on one hand, at least one electromechanical motor formed by the second motor for driving the hour indicator and the minute indicator, and on the other hand, a generator formed of the permanent magnet rotor and the stator having the at least one coil, the first wheel being fixedly connected to a pendulum hammer arranged below the electromechanical module and coaxial with the first wheel so as to enable the rotor of the generator to rotate. Attached Figure Description

[0007] The invention will now be described in more detail using the accompanying drawings, which are given by way of non-limiting example, wherein:

[0008] - Figure 1 This is a bottom perspective and partial exploded view of an embodiment of the electromechanical watch movement according to the present invention.

[0009] - Figure 2 yes Figure 1 A top view of a watch movement.

[0010] - Figure 3A and Figure 3B They are Figure 1 and Figure 2 The two sections of the watch movement along the dashed line illustrate the various components of the watch movement's electromechanical module.

[0011] - Figure 4A and Figure 4B This is a perspective view of the electromechanical module that forms the watch movement shown in the previous diagram. Detailed Implementation

[0012] With reference to the accompanying drawings, embodiments of the present invention will be described below.

[0013] The electromechanical watch movement 2 includes: an electromechanical module 4; an electronic module 6 for performing various functions and controlling the electromechanical module; and a control module 8 associated with the crown-steel crown 10 to specifically perform time setting for the pointer display 16, whose coaxial minute hand 18 and hour hand 17, each having a central axis of rotation 56, are rotated by two electromechanical motors 12 and 14 of the electromechanical module 4 via two independent gear trains. The hands 17 and 18 are mounted on two elongated gear shafts 25 and 26 aligned on the axis of rotation 56, with the gear shaft 26 located inside the toothed shaft 25 and guided by it. The gear shaft 26 is guided by a cylindrical tube 30 arranged inside the toothed shaft 26 and fastened at one end to a clamp 32 of the electromechanical module 4, which further includes a plate 50 on which various components of the module are mounted. A dial 52 is provided above the panel, in which at least one digital display can be arranged, and the dial is then electrically connected to the electronic module 6.

[0014] Figure 3AThe cross-section shows an electromechanical motor 12, particularly a Lavet-type stepper motor, which includes a rotor 12A equipped with permanent magnets and a coil 12B mounted on a magnetic circuit, thereby forming a stator with two magnetic poles around the rotor magnet 12A. A gear train between the rotor 12A and the minute hand 18 can also be seen, comprising: a central gear 23, which is fastened to an elongated toothed shaft 26 carrying the minute hand; and a gear set 24, whose gears mesh with the pinion of the rotor, and whose pinion meshes with the central gear 23 (also referred to as the second gear).

[0015] As in Figure 3B As shown in the cross-section, the electromechanical module 4 further includes a generator 20 formed by a rotor 20A and a coil 20B, the coil being conventionally mounted on the ferromagnetic core of the stator, thereby defining a magnetic circuit having two magnetic poles (pole shoes) surrounding a bipolar permanent magnet of the rotor 20A. Preferably, the magnetic circuit (especially its two pole shoes) is configured to generate a low reluctance torque for the generator's rotor, particularly by eliminating the positioning notches often found in stepper motors. To enable the electromechanical movement to be autonomous in its power supply (by being able to generate electrical energy from the acceleration that a watch equipped with such a movement might experience, particularly through the movement of the user's arm), the generator 20 is associated with a balance wheel 22, which is coaxial with the time display device.

[0016] The generator 20 is kinematically connected to the balance wheel 22 in a manner that allows for a relatively simple electromechanical module 4 and a minimal increase in the thickness of the movement after the addition of the balance wheel, which is configured to be coaxial with the pointer-type time display to rotate the generator. For this purpose, the generator is kinematically connected to the balance wheel via a wheel 40 (also referred to as the first wheel) and an intermediate wheel assembly 42 arranged between the wheel 40 and the generator's rotor 20A. The wheel 40 is provided with an axle 36, which is coaxial with the two toothed shafts 25 and 26 of the two hands 17 and 18 and is guided to rotate by a fixed cylindrical tube 30, in which a shaft 37, partially forming the axle 36, is located. Therefore, the axle 36 of the first wheel 40 does not pivot on a bearing on the side of the pointer-type display. Furthermore, as already indicated, the fixed cylindrical tube 30 also guides the rotation of the two corresponding toothed shafts of the minute and hour hands. Thus, material and components are saved due to the arrangement according to the invention.

[0017] Shaft 36 includes a lower portion 38 that causes shaft 37 to extend along the direction of a central portion 46 of a ball bearing assembly 44 mounted on an additional clamping plate 54, the central portion being rotatably movable. The lower portion 38 has a diameter larger than that of shaft 37 and is fastened to the central portion 46, to which the pendulum hammer 22 is also fastened. Thus, the first wheel 40 is fixedly connected to the pendulum hammer 22 on its side opposite the cylindrical tube 30, such that the pendulum hammer meshes with the rotor 20A of the generator 20, and thus the generator can be rotated via the first wheel. Note that the first wheel 40 is fastened to the pendulum hammer 22 without any bearing specific to the first wheel arranged on the side of the pendulum hammer, so that the first wheel is not associated with any particular pivot bearing.

[0018] In a variant not shown, the fixed cylindrical tube 30 is omitted. Therefore, the elongated gear 26 carrying the pointer / indicator 18 directly surrounds the shaft 37 of the shaft 36 of the first wheel 40, and it is this gear that then guides the rotation of the first wheel 40 on the side of the display, which is kinematically connected to the generator 20.

[0019] The electromechanical motor 12, the generator 20, a first gear train including at least a first wheel 40 and kinematically connecting the balance wheel 22 to the rotor of the generator, and a second gear train including at least a second wheel 23 and kinematically connecting the electromechanical motor to at least one indicator of the analog display together form a separate electromechanical module 4, which is removably arranged in the watch movement 2. This module 4... Figure 4A and Figure 4B The middle is shown in perspective view, where Figure 4A It is a top view, and Figure 4B These are bottom views. These figures and the preceding description illustrate a significant feature of the invention: the generator and the first gear train kinematically connected to it have an arrangement substantially corresponding to the electromechanical motor driving the second hand in a conventional motor module, wherein the second hand, coaxial with the minute and hour hands, is driven independently of these hands and for this purpose is associated with its own gear train (hereinafter referred to as the "first gear train"). As a general rule, since a stepper motor (particularly a Lavet-type stepper motor) completes two steps per revolution, the transmission ratio between the second hand wheel and the rotor of the motor in question is equal to thirty, such that the second hand performs continuous jumps, each jump corresponding to one second. Therefore, in an advantageous variant of the invention, the transmission ratio between the center wheel 40 and the generator rotor 20A is set to equal thirty so that the motor module can be used with minimal modification to the motor module. However, in a general variant, this transmission ratio is between ten and one hundred.

[0020] In the context of this invention, therefore, is provided the use of an electromechanical type motor module comprising at least: a first motor formed of a permanent magnet rotor and a stator, the stator being provided with at least one coil and associated with a first wheel having a shaft; and a second motor associated with at least a second wheel having a gear shaft intended to carry a minute indicator of a pointer-type time display, the shaft being guided to rotate by a fixed cylindrical tube around which the gear shaft is mounted or by the gear shaft itself, and intended to carry a second indicator or second counter in the motor module, to form an electromechanical module according to the invention, which on one hand includes at least one electromechanical motor including the second motor for driving the hour indicator and the minute indicator, and on the other hand includes a generator formed of the permanent magnet rotor and the stator provided with the at least one coil. According to the invention, the shaft of the first wheel extends on a side opposite to the pointer-type time display and is fixedly connected to a pendulum hammer, the pendulum hammer being arranged below the electromechanical module and coaxial with the first wheel, so as to enable rotation of the generator rotor.

[0021] In a preferred variant, the pendulum hammer 22 is fastened to the central portion 46 of the ball bearing assembly 44, which is rotatably movable and is arranged below the electromechanical module. For this purpose, an additional clamping plate 54 is provided, which is directly fastened to the electromechanical module 4 to complete it, or fastened to, for example, a frame 60 made of plastic material, in which the electromechanical module is located (see...). Figure 1 In this preferred variant, as previously described, the shaft 36 of the first wheel 40 does not pivot in the lower bearing of the electromechanical module. The first wheel is secured to the balance wheel hammer 22, and no bearing specific to the first wheel is arranged on the side of the balance wheel hammer, so that the first wheel is not associated with any particular bearing. This allows the relatively small thickness / height of the watch movement 2 to be maintained.

[0022] In certain variants, the initial motor module for manufacturing the electromechanical module according to the invention includes a stator (ferromagnetic circuit) with locating notches around the holes, wherein the permanent magnets of the rotor are arranged such that the corresponding motor is a stepper type. One of these stators is replaced by a stator without locating notches, which is then used to form a generator in the electromechanical module in order to reduce the reluctance torque in the generator.

[0023] Therefore, it should be noted that the present invention allows for the creation of an electromechanical module according to the invention from a common motor module used in electromechanical mechanisms with relatively few modifications. In fact, only the shaft of the second hand wheel must be replaced by a shaft having a lower portion on the side of the balance wheel hammer, configured for fastening to the balance wheel hammer or including such a lower portion suitable for fastening to the balance wheel hammer, which is added to drive the generator.

Claims

1. A timepiece movement (2) of the electromechanical type, comprising a time display by hands (16) and being provided with at least one electromechanical motor (12) able to drive at least one indicator of the time display by hands, and with a generator (20) comprising a rotor (20A) and being associated with a balance hammer (22) coaxial with the time display by hands, the movement comprising a first wheel (40) provided with a shaft (36) coaxial with the indicator, the shaft being guided in rotation by a pinion carrying the indicator and integral with a second wheel (23) in meshing relationship with the electromechanical motor, the pinion being rotatably mounted around a fixed cylindrical tube (30); characterized in that, The first wheel (40) is in meshing relationship with the rotor of the electric generator; and in that the first wheel is fixedly connected to the balance cock on the side opposite to the pointer time display device, so that the balance cock can rotate the rotor of the electric generator via the first wheel.

2. A timepiece movement according to claim 1, characterized in that, The balance cock (22) is fastened to a central portion (46) of a ball bearing device (44), which is rotatably mobile.

3. Timepiece movement according to claim 1 or 2, characterized in that, The first wheel (40) is fastened to the balance cock (22) without arranging on the side of the balance cock a bearing specific to the first wheel, so that the first wheel is not associated with any specific pivot bearing.

4. A timepiece movement according to claim 1 or 2, characterized in that, The electric motor (12), the electric generator (20), a first gear train comprising the first wheel and kinematically coupling the balance cock (22) to the rotor of the electric generator, and a second gear train comprising the second wheel and kinematically coupling the electric motor to the at least one indicator, form together an electromechanical module (4) separate from the other parts of the watch movement and arranged in a removable manner in the watch movement.

5. A timepiece movement according to claim 1 or 2, characterised in that, The transmission ratio between the first wheel (40) and the rotor (20A) of the electric generator (20) is equal to thirty.

6. Use of a motor module of the electromechanical type, comprising at least: A first motor formed by a permanent magnet rotor (20A) and a stator provided with at least one coil (20B) and associated with a first wheel (40) provided with a shaft, and a second motor associated with at least a second wheel (23) provided with a pinion (26) intended to carry a minute indicator (18) of a pointer time display device (16), the shaft being guided in rotation by a fixed cylindrical tube (30) or directly by the pinion, and intended to carry a second indicator or a second counter in the motor module, to form an electromechanical module (4) comprising on the one hand at least one electric motor (12, 14) formed by the second motor for driving an hour indicator (17) and the minute indicator (18), and on the other hand an electric generator (20) formed by the permanent magnet rotor and the stator provided with the at least one coil, the first wheel (40) being fixedly connected to a balance cock (22) arranged coaxially below the electromechanical module so as to be able to rotate the rotor of the electric generator.

7. Use of a motor module according to claim 6, characterized in that The balance cock (22) is fastened to a central portion (46) of a ball bearing device (44), which is rotatably mobile, the ball bearing device being arranged below the electromechanical module (4).

8. Use of a motor module according to claim 7, characterized in that The shaft of the first wheel (40) is replaced by a shaft (36) configured so as to allow it to be fastened to the balance cock, the first wheel being fastened to the balance cock associated with the electromechanical module without arranging on the side of the balance cock a bearing specific to the first wheel, so that the first wheel is not associated with any specific bearing. The balance cock (22) is fastened to a central portion (46) of a ball bearing device (44), which is rotatably mobile, the ball bearing device being arranged below the electromechanical module (4). The shaft of the first wheel (40) is replaced by a shaft (36) configured so as to allow it to be fastened to the balance cock, the first wheel being fastened to the balance cock associated with the electromechanical module without arranging on the side of the balance cock a bearing specific to the first wheel, so that the first wheel is not associated with any specific bearing.

9. Use of a motor module according to any one of claims 6 to 8, characterized in that, Said stator has a positioning notch, said stator being replaced by a stator without a positioning notch in said electromechanical module (4) in order to reduce the reluctance torque in said electric generator.

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