CH718652A2 - Watch movement including a generator. - Google Patents

Abstract

The invention relates to an electromechanical watch movement (2) comprising an analog time display device (25, 26) and provided with at least one electromechanical motor, for driving at least one indicator of the analog time display. time, and a generator (20) comprising a rotor (20A) and associated with an oscillating mass (22) coaxial with the time display device, this watch movement comprising a first wheel (40) provided with a shaft (36), coaxial with said indicator, which is guided in rotation, in a main embodiment, by a fixed cylindrical tube (30) around which is mounted, movable in rotation, at least one barrel (26) of the device time display. The first wheel (40) is in meshing relation with the rotor of the generator and is fixedly connected to the oscillating mass, on the side opposite to the analog time display, so that this oscillating mass can rotate the generator rotor via the first wheel.

Description

Technical field of the invention

The present invention relates to a clock movement provided with an analog time display and comprising at least one part consuming an electric current, this clock movement further comprising a generator / micro-generator (hereafter after named 'generator') capable of producing electrical energy in order to be able to supply said part consuming an electrical current.

Technology background

[0002] Document EP 0 998 009 describes, in a first embodiment, a watch movement equipped with a generator whose rotor is coupled directly to an oscillating weight. The oscillating mass is fixed by a screw to a wheel in gear relation with the rotor of the generator. For example, it is expected that the cog between the oscillating mass and the rotor presents a multiplication by 100 of the speed of rotation. No technical explanation is given as to the arrangement of the oscillating weight 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 analog display is driven by an independent motor, this assembly being represented independent of the assembly formed by the generator and the oscillating weight, without any particular disclosure as to mounting the oscillating weight in the watch movement. Document EP 0 326 312, in the name of the same owner, shows in section, in its figure 2(a), a technical teaching as to the arrangement of the 'generator and oscillating mass assembly associated with a first cog' and of the 'electric motor and analogue display with three coaxial hands combined with a second gear train'. According to this technical teaching, the seconds hand is pivoted downwards in a bridge 12. Under this bridge is provided another bridge 13 in which is arranged a ball bearing. The oscillating mass is fixed by a screw to the central part of the ball bearing which can rotate. To transmit the force torque to the rotor of the generator, a central wheel integral with the oscillating mass is arranged between the bridge 13 and the disk of the oscillating mass, this central wheel meshing with a pinion arranged at the same level. This arrangement is cumbersome and complex with a stack of several wheels, a lower bearing for the seconds wheel arranged in an intermediate bridge, a ball bearing arranged in a lower bridge and, in addition, a central wheel between the lower bridge and the oscillating mass to be able to transmit, via an off-center mobile, the torque to the generator.

Summary of the invention

The present invention aims to provide an electromechanical movement provided with a generator which is less bulky, less complex and less expensive than the movement of the same type described in document EP 0 326 312 cited above. In particular, it is expected that the electromechanical movement according to the invention requires few modifications and no additional height relative to a conventional electromechanical movement having a central oscillating weight and an analog time display with three hands that is also central.

To this end, the present invention relates to a watch movement of the electromechanical type comprising an analog time display device and provided with at least one electromechanical motor, to drive at least one indicator of the analog display, and a generator comprising a rotor and associated with an oscillating weight which is coaxial with the time display device. The watch movement comprises a first wheel provided with a shaft, coaxial with said indicator, which is guided in rotation by a barrel carrying this indicator and secured to a second rotating wheel meshing with the electromechanical motor or by a fixed cylindrical tube around which is mounted, mobile in rotation, the barrel. According to the invention, the first wheel is in meshing relationship with the rotor of the generator, this first wheel being fixedly connected to the oscillating weight on the side opposite to the analog display, so that this oscillating weight can rotate the generator rotor via the first wheel.

[0005] Thanks to the characteristics of the invention, the central wheel fixed to the oscillating mass, to drive the rotor of the generator in rotation via a first cog, is formed in a manner similar to a seconds wheel with a shaft guided in rotation. , on the side of the analog display, by a fixed cylindrical tube around which is mounted, mobile in rotation, the barrel of the minute wheel or by this barrel itself. This arrangement makes it possible to reduce the size of the watch movement, in particular to reduce its height/thickness. Preferably, the analog display is provided without a seconds indicator which is coaxial with the minutes indicator. However, in a particular embodiment which will not be described in detail hereafter, a seconds indicator coaxial with the minutes indicator is provided. In the latter case, the seconds indicator is then mounted on a barrel of a seconds wheel inside which is arranged, movable in rotation, said shaft of said central wheel, the barrel of the minute wheel then being mounted around the barrel of the seconds wheel.

According to the invention, it is also proposed to use a motor module of the electromechanical type comprising at least a first motor, formed of a permanent magnet rotor and a stator provided with at least one coil and associated with a first wheel fitted with a shaft, and a second motor associated with at least a second wheel fitted with a barrel intended to carry a minute indicator of an analogue time display, said shaft being guided in rotation by a fixed cylindrical tube around which said gun is mounted or by this gun itself and intended to carry in said motor module a seconds indicator or seconds counter, to form an electromechanical module comprising, on the one hand, at least one electromechanical motor, formed by said second motor, for driving an hour indicator and said minute indicator and, on the other hand, a generator formed by said permanent magnet rotor and said stator provided with said at least one coil, the first one wheel being fixedly connected to an oscillating mass arranged under said electromechanical module, coaxially to this first wheel, in order to be able to drive the rotor of the generator in rotation.

Brief description of figures

The invention will be described below in more detail using the accompanying drawings, given by way of non-limiting examples, in which: Figure 1 is a view from below, in perspective and partially exploded, of an embodiment of an electromechanical timepiece movement according to the invention. Figure 2 is a top view of the watch movement of Figure 1. Figures 3A and 3B are respectively two parts of a cross section of the watch movement of Figures 1 and 2 along a broken line to show various elements of the electromechanical module of this watch movement. Figures 4A and 4B are perspective views of an electromechanical module forming the watch movement of the previous figures.

Detailed description of the invention

With reference to the appended figures, an embodiment according to the invention will be described below.

[0009] The watch movement 2 of the electromechanical type comprises an electromechanical module 4, an electronic module 6 to perform various functions and control the electromechanical module, a control module 8 associated with a stem-crown 10 in particular to perform a time of an analog display 16 whose minute hand 18 and hour hand 17, coaxial and having a central axis of rotation 56, are respectively driven in rotation, via two independent gear trains, by two electromechanical motors 12 and 14 of the electromechanical module 4. The needles 17 and 18 are respectively mounted on two elongated barrels 25 and 26 which are aligned on the axis of rotation 56, the barrel 26 being located inside the barrel 25 which is guided in rotation by this barrel 26. Barrel 26 is guided in rotation by a cylindrical tube 30 which is arranged inside this barrel 26 and fixed, at one end, to a bridge 32 of the electromechanical module 4, which comprises also a plate 50 on which are mounted the various elements of this module. Above the plate is provided a dial 52 in which at least one digital display can be arranged, this dial then being electrically connected to the electronic module 6.

The section of Figure 3A shows the electromechanical motor 12, in particular a stepping motor of the Lavet type, which comprises a rotor 12A provided with a permanent magnet and a coil 12B mounted on a magnetic circuit forming a stator having two magnetic poles around the rotor magnet 12A. We also see the gear train between the rotor 12A and the minute hand 18, this train train comprising a central wheel 23 fixed to the elongated barrel 26 carrying the minute hand, a mobile 24 whose wheel meshes with a pinion of the rotor and whose the pinion meshes with the central wheel 23, also called the second wheel.

As shown in the section of Figure 3B, the electromechanical module 4 further comprises a generator 20 formed of a rotor 20A and a coil 20B which is conventionally mounted on a ferromagnetic core of a stator defining a circuit magnet with two magnetic poles (pole shoes) which surround the bipolar permanent magnet of the rotor 20A. Preferably, the magnetic circuit, in particular its two pole shoes, are configured so as to generate a low reluctant torque for the rotor of the generator, in particular by eliminating the positioning notches often provided in stepper motors. For the electromechanical movement to be autonomous in terms of its supply of electrical energy, by being capable of producing electrical energy from accelerations to which the watch equipped with such a horological movement may be subjected, in particular by movements of a user's arm, the generator 20 is associated with an oscillating mass 22 which is coaxial with the time display device.

[0012] The generator 20 is kinematically connected to the oscillating mass 22 in a way that makes it possible to keep a relatively simple electromechanical module 4 and to have a lesser increase in thickness of the movement following the addition of the oscillating mass provided coaxial with the analog time display to drive the generator in rotation. To do this, the generator is kinematically connected to the oscillating mass via a wheel 40, also called the first wheel, and an intermediate mobile 42 arranged between this wheel 40 and the rotor 20A of the generator, the wheel 40 being provided with a shaft 36 which is coaxial with the two barrels 25 and 26 of the two needles 17 and 18 and which is guided in rotation by a fixed cylindrical tube 30 in which is located a shaft 37 partially forming the shaft 36. Thus, the shaft 36 of the first wheel 40 is not pivoted in a bearing on the analog display side. Moreover, the fixed cylindrical tube 30 is, as already indicated, also used to guide in rotation the two respective barrels of the minute and hour hands. There is therefore a saving in material means thanks to the arrangement according to the invention.

The shaft 36 comprises a lower part 38 which extends the axis 37 in the direction of the central part 46, movable in rotation, of a ball bearing device 44 which is mounted on an additional bridge 54. This part bottom 38 has a diameter greater than that of axle 37 and is fixed to central part 46, to which oscillating weight 22 is also fixed. First wheel 40 is therefore fixedly connected to oscillating weight 22 on the side opposite the cylindrical tube 30, so that this oscillating mass is in meshing relationship with the rotor 20A of the generator 20 and can thus drive the generator in rotation via this first wheel. It will be noted that the first wheel 40 is fixed to the oscillating weight 22 without the arrangement of a bearing specific to this first wheel on the side of this oscillating weight, so that the first wheel is not associated with any own pivot bearing. .

In a variant not shown, the fixed cylindrical tube 30 is omitted. Thus, the elongated barrel 26, which carries the needle/indicator 18, directly surrounds the axis 37 of the shaft 36 of the first wheel 40 and it is this barrel which then guides in rotation, on the side of the display, the first wheel 40 which is kinematically coupled to the generator 20.

[0015] The electromechanical motor 12, the generator 20, a first gear train comprising at least a first wheel 40 and kinematically coupling the oscillating mass 22 to the rotor of the generator, and a second gear train comprising at least a second wheel 23 and kinematically coupling the electromechanical motor to at least one indicator of the analog display, together form a separate electromechanical module 4 which is arranged in the watch movement 2 in a removable manner. This module 4 is shown in perspective in Figures 4A and 4B, Figure 4A being a top view while Figure 4B is a bottom view. It is observed in these Figures and in the preceding description a remarkable characteristic of the invention, namely that the generator and the first cog which kinematically connects it to the oscillating mass have an arrangement corresponding substantially to that of an electromechanical motor driving a needle seconds in a conventional motor module in which this seconds hand, coaxial with the minute and hour hands, is driven independently from these minute and hour hands and is, for this purpose, associated with its own gear train, named above 'first cog'. As a general rule, since a stepper motor, in particular of the Lavet type, performs two steps per revolution, the transmission factor between the seconds wheel and the rotor of the motor in question is equal to thirty, so that the seconds hand successively makes jumps each corresponding to one second. Thus, in an advantageous variant of the invention, the transmission ratio between the central wheel 40 and the rotor 20A of the generator is provided equal to thirty in order to be able to use a motor module by modifying it to the minimum. However, in a general variant, this transmission ratio is between ten and one hundred.

[0016] In the context of the invention, provision is therefore made for the use of a motor module of the electromechanical type comprising at least a first motor, formed of a permanent magnet rotor and a stator provided with at least one at least one coil and associated with a first wheel fitted with a shaft, and a second motor associated with at least one second wheel fitted with a barrel intended to carry a minute indicator of an analog time display, said shaft being guided in rotation by a fixed cylindrical tube around which said barrel is mounted or by this barrel itself and intended to carry in said motor module a seconds indicator or seconds counter, to form an electromechanical module according to the invention which comprises , on the one hand, at least one electromechanical motor, including the second motor, for driving an hour indicator and said minute indicator and, on the other hand, a generator formed by said permanent magnet rotor and said stator provided with said at least s a coil. According to the invention, the shaft of the first wheel is extended on the side opposite the analog time display and fixedly connected to an oscillating weight arranged under said electromechanical module, coaxially to this first wheel, in order to be able to drive rotating the generator rotor.

In a preferred variant, the oscillating mass 22 is fixed to a central part 46, movable in rotation, of a ball bearing device 44 which is arranged under the electromechanical module. For this purpose, an additional bridge 54 is provided which is fixed directly to the electromechanical module 4 to complete it or to a frame 60, for example made of plastic material, in a housing of which the electromechanical module is located (see FIG. 1). In this preferred variant, as already described previously, the shaft 36 of the first wheel 40 is not pivoted in a lower bearing in the electromechanical module, this first wheel being fixed to the oscillating mass 22 without the arrangement of a own bearing to this first wheel on the side of the oscillating mass, so that the first wheel is not associated with any own bearing, which makes it possible to maintain a relatively small thickness/height of the watch movement 2.

In a particular variant, the initial motor module used to produce the electromechanical module according to the invention comprises stators (ferromagnetic circuits) having positioning notches around the hole in which the permanent magnet of the rotor is arranged so that the corresponding motors are of the stepper type. One of these stators is replaced by a stator without positioning notches which is then used to form the generator in the electromechanical module, so as to reduce a reluctant torque in the generator.

It is therefore noted that the present invention makes it possible to start from a usual motor module for an electromechanical movement and to obtain the electromechanical module according to the invention with relatively little modification. Indeed, only the axle of the seconds wheel must be replaced by a shaft having a lower part, on the side of the oscillating weight, configured for attachment to this oscillating weight or be completed with such a lower part which is suitable for an attachment to the oscillating mass, which is added to drive the generator.

Claims (9)

1. Watch movement (2) of the electromechanical type comprising an analog time display device (16) and provided with at least one electromechanical motor (12), in order to be able to drive at least one indicator (18) of the analog display, and a generator (20) comprising a rotor (20A) and associated with an oscillating weight (22) which is coaxial with the time display device, this watch movement comprising a first wheel (40) provided a shaft (36), coaxial with said indicator, which is guided in rotation by a barrel carrying said indicator and integral with a second wheel (23) rotating in mesh with the electromechanical motor or by a fixed cylindrical tube (30 ) around which is mounted, mobile in rotation, said barrel; characterized in that the first wheel (40) is in meshing relationship with the rotor of the generator; and in that the first wheel is fixedly connected to the oscillating mass, on the side opposite the analogue time display, so that this oscillating mass can rotate the rotor of the generator via the first wheel. 2. Timepiece movement according to claim 1, characterized in that the oscillating mass (22) is fixed to a central part (46), movable in rotation, of a ball bearing device (44). 3. Watch movement according to claim 1 or 2, characterized in that the first wheel (40) is fixed to the oscillating weight (22) without the arrangement of a bearing specific to this first wheel on the side of this oscillating weight, so that the first wheel is not associated with any own pivot bearing. 4. Watch movement according to any one of the preceding claims, characterized in that the electromechanical motor (12), the generator (20), a first cog (40, 42) comprising the first wheel and kinematically coupling the oscillating weight (22) to the rotor of the generator, and a second cog comprising the second wheel and kinematically coupling the electromechanical motor to said at least one indicator (18) together form an electromechanical module (4) which is separate from the other parts of the watch movement and arranged in this watch movement detachably. 5. Watch movement according to any one of the preceding claims, characterized in that the transmission ratio between the first wheel (40) and the rotor (20A) of the generator (20) is equal to thirty. 6. Use of a motor module of the electromechanical type comprising at least a first motor, formed of a permanent magnet rotor (20A) and a stator provided with at least one coil (20B) and associated with a first wheel (40) provided with an axle, and a second motor (12) associated with at least one second wheel (23) provided with a barrel (26) intended to carry a minute indicator (18) of an analog display of the time (16), said axis being guided in rotation by a fixed cylindrical tube (30), around which said barrel is mounted, or directly by this barrel and intended to carry in said motor module a seconds indicator or seconds counter , to form an electromechanical module (4) comprising, on the one hand, at least one electromechanical motor (12, 14), formed from said second motor, for driving an hour indicator (17) and said minute indicator (18) and, on the other hand, a generator (20) formed by said permanent magnet rotor and said stator provided with said at least anointed with a coil, the first wheel (40) being fixedly connected to an oscillating mass (22) which is arranged under said electromechanical module, coaxially to this first wheel, in order to be able to drive the rotor of the generator in rotation. 7. Use of a motor module according to claim 6, wherein the oscillating mass (22) is fixed to a central part (46), movable in rotation, of a ball bearing device (44) which is arranged under the electromechanical module (4). 8. Use of a motor module according to claim 7, wherein the axis of the first wheel (40) is replaced by a shaft (36) configured so as to allow its attachment to the oscillating mass, this first wheel being fixed to the oscillating weight associated with said electromechanical module without the arrangement of a bearing specific to this first wheel on the side of this oscillating weight, so that the first wheel is not associated with any proper bearing. 9. Use of a motor module according to any one of claims 6 to 8, wherein said stator has positioning notches, this stator being replaced by a stator without positioning notches in said electromechanical module (4) so as to reduce a reluctant torque in the generator.