Regulating body for a wristwatch

Abstract

Regulating body for a wristwatch, comprising: a generator provided with a rotor and a stator with M+N coils, M being a whole number higher than, or equal to, 1; and an electronic regulating circuit having a first load impedance with an adjustable value for adjusting the current in N of said M+N coils, and therefore the rotational speed of the rotor. Only a limited number of coils is therefore used for the braking, the other coils continuing to supply the electronic regulating circuit.

Claims

1. Regulating member for a wristwatch, comprising: a generator provided with a rotor and a stator with M+N coils, M and N being each a whole number greater than or equal to 1; and an electronic regulating circuit arranged for controlling the braking of the rotor, characterized in that the circuit is arranged for controlling the braking exerted by the M coils differently from the braking exerted by the N coils.

2. The regulating member according to claim 1, wherein M and N are both greater than or equal to 2.

3. The regulating member according to claim 1, wherein the electronic regulating circuit comprises a first adjustable-value load impedance in order to adjust the current in the N of said M+N coils and thus the rotation speed of the rotor.

4. Regulating member according to claim 3, wherein said first adjustable-value load impedance is connected in parallel with said N coils.

5. Regulating member according to claim 4, wherein said M coils are not connected in parallel with said first adjustable-value load impedance.

6. Regulating member according to claim 3, wherein the first adjustable-value load impedance is connected upstream of the electronic regulating circuit.

7. Regulating member according to claim 3, wherein said first adjustable-value load impedance comprises several discrete impedances that can be individually selected in order to control the value of the first load impedance between several discrete values.

8. The regulating member according to claim 1, characterized by a second fixed-value load impedance, wherein said second load impedance is connected at least to said M coils.

9. Regulating member according to claim 8, wherein the second fixed-value load impedance is traversed by a current determined by the whole of said M+N coils.

10. Regulating member according to claim 9, wherein the second fixed-value load impedance is connected downstream of said electronic regulating circuit.

11. The regulating member according to claim 1, wherein M and N are fixed and do not vary during the operation of the generator.

12. The regulating member according to claim 1, wherein the electronic regulating circuit is arranged for varying M and N during the operation of the generator, so as to vary the number of coils assigned to controlling the braking.

13. Regulating member according to claim 1, wherein said M coils are connected serially with said N coils, wherein the electronic regulating circuit is powered by the voltage at the terminals of the M+N coils.

14. Regulating member according to claim 1, wherein said electronic regulating circuit is arranged for controlling the braking of the rotor by applying braking cycles, wherein each cycle comprises a first braking period with a fixed braking intensity and a second braking period with a braking intensity that depends on the advance of the rotor.

15. Regulating member according to claim 14, wherein said electronic regulating circuit is arranged for modifying the braking intensity during said second period and for keeping a braking intensity constant during said first period.

16. Regulating member according to claim 15, wherein said electronic regulating circuit is arranged for keeping a braking intensity at zero during said first period.

17. Regulating member according to claim 14, wherein said electronic regulating circuit is arranged for modifying the duration of said cycles.

18. Regulating member according to claim 17, wherein said electronic regulating circuit is arranged for indicating the running reserve by varying the duration of said cycles according to the energy available in a barrel.

19. Regulating member according to claim 1, wherein said electronic regulating circuit comprises a quartz oscillator, a system for counting pulses (down) generated from the quartz oscillator and pulses (up) generated from signals at the output of said coils, and a control system of said first load impedance in order to adjust the value of said first load impedance depending on the counting system.

20. Regulating member according to claim 1, wherein said coils have an ovoid shape.

21. Watch movement comprising a regulating member according to claim 1.

22. Regulating member for a wristwatch, comprising: a generator provided with a rotor and a stator with M+N coils, M and N being each a whole number greater than or equal to 1; and an electronic regulating circuit arranged for controlling the braking of the rotor, characterized in that the circuit is arranged for controlling the braking exerted by the M coils differently from the braking exerted by the N coils, wherein the electronic regulating circuit comprises a first adjustable-value load impedance in order to adjust the current in the N of said M+N coil and thus the rotation speed of the rotor.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Examples of embodiments of the invention are indicated in the description illustrated by the attached figures in which:

(2) FIG. 1 illustrates diagrammatically a generator according to one embodiment of the invention.

(3) FIG. 2 is a simplified electric diagram of the electronic circuit according to one embodiment of the invention.

(4) FIG. 3 is a simplified electric diagram of a variant electronic circuit according to one embodiment of the invention.

(5) FIG. 4 illustrates diagrammatically an adjustable load impedance Z1 according to one embodiment of the invention.

EXAMPLE(S) OF EMBODIMENTS OF THE INVENTION

(6) The regulating member for a wristwatch comprises a generator illustrated diagrammatically in FIG. 1. The generator of this example comprises a rotor 12 mounted on the arbor 120 of a pinion or of a wheel (not represented) connected to the geartrain of a mechanical movement (not represented) whose speed it regulates. The rotor 12 comprises a plate with magnetic portions, not represented, for example discrete magnets or magnetized portions, that generate a rotating magnetic field when the rotor is driven in rotation by the geartrain of a mechanical movement. In one variant, it is also possible to provide a rotor with several plates, for example a rotor with two coaxial plates superimposed one above the other.

(7) The generator further comprises a stator with coils 10, 10′ placed so that the rotating magnetic field generated by the rotation of the rotor 12 induces induced voltages in the coils. The figure illustrates a construction with six coils spread angularly in a roughly regular manner. The number of coils can be different. In the case of a rotor with two plates, the coils are advantageously mounted on a printed circuit, for example a PCB, passing through the two rotor plates.

(8) The coils 10, 10′ of this example have a roughly ovoid or roughly trapezoidal shape, so that their section increases when moving away from the center of the generator. This particular shape enables the coils to be placed as closely together as possible near the center whilst taking advantage of the improved coupling provided thanks to the greater section of the coils on the outside. The ovoid shape can for example be achieved by a coiling process in which the coiling tension is modified at each half turn, so as to tighten the spires on the inside more than on the outside. This ovoid shape can also be used in clockwork generators used with any kind of electronic regulating circuits, for example circuits such as described in the remainder of this application, or different circuits.

(9) Other types of generators can be used in the frame of this invention, including the generator described in EP-B1-851322 or that described in EP-B1-1171806, the contents of both applications being hereby included by reference.

(10) FIG. 2 illustrates a simplified electric diagram of the electronic circuit 2 for regulating the rotation speed of the rotor according to the invention. A certain number of elements of this circuit can be identical to those of EP-B1-1276024, the content of which is hereby included by reference. Most of the elements of this circuit, with the exception of the coils 10, 10′, of the quartz 23 and possibly of the capacity C2, can be executed in the form of an integrated circuit, for example an asic circuit.

(11) The electric coils 10, 10′ of the stator described further above are connected serially and grouped in two groups. The group comprising the coils 10′ can for example comprise N=2 coils designed for braking and powering electrically the electronic circuit. The group comprising the coils 10 can for example comprise M=4 coils designed solely to powering electrically the electronic circuit.

(12) The element Z1 is a variable-value load impedance, in this embodiment a simple resistor, connected in parallel with the N coils 10′ designed for braking. One example of embodiment of the impedance Z1 is illustrated and will be described further below in relation with FIG. 4. In one embodiment, the load impedance Z1 comprises several resistors 910-916 with a variable value connected in parallel. Switches 901-906 are provided in each branch of the circuit and can be selected individually by means of a digital signal B0-B31 determined at each instant by the circuit in order to adapt the intensity of braking to the speed or the advance of the rotor.

(13) The element 3 is a rectifier-cum-voltage-multiplier circuit that enables the alternating voltage at the terminals of the M+N coils to be converted into a continuous and multiplied voltage V.sub.dd that is stored in the storage capacity C2 and powers the whole of the electronic circuit. The circuit represented is based on the use of diodes D1-D3 and of capacitors C1 and C3 for rectifying and multiplying the current. In order to prevent voltage drops in the diodes, they can advantageously be replaced, after startup, by transistors controlled by comparators comparing the voltage value upstream and downstream of the diode, according to the process described in EP-B1-1276024.

(14) The capacity C2 is a storage capacity of relatively high value that enables the voltage at the output of the rectifier 3 to be maintained at a level V.sub.dd approximately constant, even when the voltage induced in the coils 10, 10′ fluctuates.

(15) The impedance Z2 is a load impedance, in this example a simple resistor, of preferably fixed value, connected to the M power supply coils 10 and in this embodiment also, connected to the N braking coils 10′. “Connected” in this context means that a variation of the load impedance Z2 would influence the current generated by the M+N coils, or, in other words, that the current passing through this load impedance Z2 depends on the voltage induced by the M+N coils 10, 10′. The term “fixed” in this context means that the value of the impedance Z2 is not adjustable and that it is not adjusted deliberately; variations of this impedance can however occur during use.

(16) This impedance Z2 can be constituted by a discrete component, by an integrated circuit, or can possibly be constituted by the input impedance of the electronic regulating circuit 2.

(17) The load impedances Z1, Z2 illustrated in FIG. 2 are simple resistors. Other types of impedances, including impedances comprising capacitive or inductive components, can be used.

(18) The element 20 is a hysteresis comparator that compares at each instant the voltage VM2 at the terminals of the M+N coils 10, 10′ and generates a rectangular signal that changes direction at each polarity inversion. Ascending and/or descending flanks of this rectangular signal can thus be used as pulses whose rhythm determines the rotation frequency of the rotor 12. In one variant embodiment, the comparator 20 could compare the voltage VM1 at the terminals of the coils 10 that are not braked, or at the terminals of a portion of these un-braked coils.

(19) The element 23 is a quartz forming with the oscillator 24 a reference oscillator whose frequency of the output signal is divided by the frequency divider 25 in order to correspond with the rotation speed at which the rotor 12 is to be set. The output signal “down” at the output of this frequency divider is supplied at the decrementation input of a bidirectional counter 22.

(20) The element 21 is an anti-coincidence circuit that enables the pulses at the output of the comparator 20 to be shifted relative to the pulses at the output of the frequency divider 25 when these two pulses occur at the same instant. The output signal “up” at the output of this anti-coincidence circuit 21 is supplied at the incrementation input of the bidirectional counter 22.

(21) The bidirectional counter 22 stores a binary value B0:B31 that is incremented at each “up” pulse coming from the generator, and decremented at each “down” pulse coming from the quartz oscillator 23, 24. Thus, the value of this counter increases when the generator turns too fast relative to the reference signal given by the quartz, and diminishes when it turns less fast. This signal B0:B31 is used to adjust the value of the variable impedance Z1 and thus for adjusting the braking torque.

(22) A logic, not represented, can be provided at the output of the counter 22, or as part of this counter, in order to adjust the digital signal B0:B31 and thus the braking intensity according to a linear or preferably non-linear ratio relative to the counted value. For example, in order to avoid momentary voltage drops, it is possible to eliminate any braking when the rotor 12 of the generator 10, 12 turns very slowly, even if it is in advance relative to the quartz oscillator signal, in order to quickly reach the voltage value allowing the circuit to be powered. The braking torque applied can for example comprise a component proportional to the momentary speed difference, to the derivation of this difference and/or to the integral of this difference. A massive braking can furthermore be provided in case of excessive speed or, on the contrary, of exceedingly slow speed, in order to stop the watch when the indications displayed risk being incorrect. The braking is preferably interrupted in the startup phase, in order to make the rotor turn in free rotation and reach as quickly as possible an induced voltage sufficient for powering the electronics.

(23) The braking is thus performed only by means of the N coils 10′ that are connected to the variable load impedance Z1 whose value decreases when the value counted by the counter 22 increases, in order to brake the generator by a high current. On the other hand, the M other coils 10 are connected to a load impedance Z2 that is practically constant, so that the alternating voltage VM1 at the terminals of these other coils remains practically constant (average value or RMS), even when the generator is being braked. This enables a voltage VM2 to be maintained at the terminals of the coils 10, 10′ that is sufficient for powering the electronic circuit 2, even during braking.

(24) The supply voltage V.sub.dd is thus maintained at a high value, preferably sufficient for powering the electronic circuit 2, even during periods of braking. However, the braking torque applied with a reduced number of coils is reduced. It is thus possible, thanks to this circuit, to brake for longer than if the braking were performed in a sudden manner with all the coils.

(25) In one embodiment, the device is sized so that during a normal use of the watch, the rotor is braked permanently, or nearly permanently, with variable braking intensities, in order to make it turn at its nominal speed. This mode of operation makes it possible to save the energy available and thus the watch's running reserve, whilst limiting the risk of the electronic circuit stopping after a sudden braking. In this manner, such a permanent braking can serve to make the circuit and the system less sensitive to disturbances.

(26) In another embodiment, braking cycles are applied to the rotor. Each cycle comprises for example a first period of duration T1 during which the rotor turns freely without being braked by the coils, and a second period of duration T2 during which the intensity of braking is controlled depending on the advance of the generator, so as to control the running of the watch. The watch thus advances at irregular speed, by accelerating during the periods of duration T1 and decelerating during the periods of duration T2. Tests have shown that, surprisingly, this mode of operation proves economical and enables the duration of the watch's running to be extended. It is possible to provide cycles comprising more than one braking period and/or more than one period of non-braking. It is possible to not interrupt fully the braking for the duration T1 but to reduce it or to apply constant braking.

(27) The total duration T1+T2 of each cycle can be fixed. The ratio between T1 and T2 can vary so as to control the running of the watch by adjusting the duration of the braking. The duration of each cycle T1+T2 is advantageously sufficiently short so that the user only perceives marginally or not at all the irregular movement of the seconds' hand. This duration can be adjusted depending on the energy available in the barrel, so as to extend the duration of the cycle and to function in a more efficient manner when the barrel is discharging. A very discharged state of the barrel, shortly before the watch stops, can be indicated by means of a very long cycle duration T1+T2, for example greater than 3 seconds, preferably greater than 5 seconds for example 10 seconds. Such a duration produces a jerky movement of the seconds' hand, very perceptible, indicating to the user that it is necessary to rewind the watch.

(28) In FIG. 2, the fixed load impedance Z2 for the coils 10 and 10′ powering the circuit is downstream of the rectifier-cum-multiplier 3, whilst the variable load impedance Z1 for the coils 10′ that also serve for braking are upstream of this rectifier 3. It is also possible, as illustrated diagrammatically in FIG. 3, to provide a fixed load impedance Z2 for the coils 10 and 10′ powering the circuit upstream of the rectifier-cum-multiplier 3; the other components of the circuit can be identical to those of FIG. 2.

(29) In another variant embodiment, not illustrated, it is also possible to use all the coils 10, 10′ for braking, but with different braking intensities. Thus, a first group of M coils can be connected to a first adjustable-value load impedance and a second group of N coils can be connected to a second adjustable-value load impedance, wherein the value of the first load impedance is different from the value of the second load impedance, at least at some instants. This enables for example all the impedances to be used for braking, but with different contributions. It is possible for example to use one of the groups of coils for braking only when an intensive braking is required, whilst the other group will be used more frequently and/or with higher braking intensities. It is also possible to have more than two groups of coils, with each group being connected, at least at certain instants, to different load impedances.

(30) It is also possible to use distinct braking durations for different coils, during each period of the electric signal. For example, a first group of coils can be used for braking over a first duration, for example permanently, whilst another group of distinct coils can be used for braking only over a second duration that is nonzero but less than the first duration.

(31) It is possible to interrupt the braking of all the coils during a brief instant each time the coils' output voltage is at the maximum, in order to make use of this voltage peak to charge the storage capacity C2. The duration of the interruption can vary according to the coils.

(32) In another variant embodiment, not illustrated, the selection of coils 10′ whose value is adjusted in order to vary the braking torque is modified. A first group of coils is used for braking at a first instant and a second group is used for braking at a second instant.

(33) FIG. 4 illustrates an example of adjustable-value load impedance Z1 according to one embodiment of the invention. The value of the impedance Z1 depends on the digital signals B0-B31 of the counter 22 (or of the digital signals derived from the signals at the output of the counter). As previously mentioned, the impedance Z1 can be connected directly to the terminals of the braking coils 10′, upstream of the rectifier 2. It is also possible to provide a load impedance for braking downstream of a rectifier, and/or several variable-value impedances allocated individually to braking with the different braking coils 10′.

(34) The impedance Z1 comprises in this example of embodiment several resistors 900 to 906, for example resistors integrated in an integrated circuit. Each resistor 900 to 906 is connected serially with a switch 910 to 916 respectively. The switches 910 to 916 are controlled by the signals B0 to B4 and B30-B31 coming from the counter 22 (or from a logic upstream of this counter 22). The value of the different resistors 910 to 916 is inversely proportional to the significance of the bits B0 to B31, so that the activation of the bit B31, for example, produces a braking significantly higher than the activation of the bit B0.

(35) The switches 900 to 906 can be constituted by field-effect transistors of type N that are blocked when the grid voltage is zero and open if this voltage takes on the logic value 1.

(36) An additional field-effect transistor 920 can be connected serially with the whole of the resistors, in order to increase the impedance when this transistor is blocked and no braking is desired. This transistor 920 can be for example a P-channel transistor controlled by an active signal LV (at 0) for example when starting up, or at other instants when the braking needs to be interrupted.

(37) In order to ensure a clean switching of the transistors 900 to 906 and 920, and clearly differentiated open resp. blocked states, it is possible to use voltage multipliers in order to multiply the voltages applied to the grids of these transistors.

REFERENCE NUMBERS USED IN THE FIGURES

(38) 10 Stator coils serving only for the electric power supply 10′ Stator coils serving for braking and powering 12 Magnetic rotor 120 Arbor of the rotor 2 Electronic regulating circuit 20 Hysteresis comparator—of the system for counting pulses from the generator 21 Anticoincidence circuit 22 Counter of the system for counting pulses from the generator and of the system for counting pulses from the quartz oscillator 23 Quartz 24 Oscillator 25 Frequency divider 3 Rectifier and voltage multiplier 900:906 Switches (N-FET transistors) 910:916 Integrated resistors 920 Switch (P-FET transistor) B0:B31 Control signals of the impedance Z1 C1 First capacity C2 Second storage capacity C3 Third capacity D1 First diode of the rectifier D2 Second diode of the rectifier D3 Third diode of the rectifier LV Signal to interrupt the braking Z1 First load impedance (adjustable) Z2 Second load impedance (fixed or adjustable) VM1 Voltage at the terminals of the coils 10 VM2 Voltage at the terminals of the coils 10+10′ VM3 Voltage at the terminals of the coils 10′ Vdd Voltage at the output of the rectifier-multiplier Vss Earth voltage