Search

EP-4414793-B1 - MECHANICAL WATCH HAVING MECHANICAL MOVEMENT AND AN ELECTRONIC SPEED GOVERNING APPARATUS.

EP4414793B1EP 4414793 B1EP4414793 B1EP 4414793B1EP-4414793-B1

Inventors

  • FUJISAWA, TERUHIKO

Dates

Publication Date
20260506
Application Date
20240207

Claims (9)

  1. A mechanical watch (1) comprising: a spiral spring (12); a balance (30) configured to be driven by power from the spiral spring; an oscillation circuit (51) configured to output a clock signal; a vibration detection unit (47) configured to detect a vibration of the balance and output a vibration detection signal; a speed governing unit (43) including a permanent magnet (36) and a coil (35); a speed governing control unit (50) configured to control the speed governing unit to perform a speed governing control of the balance; a storage unit (44) configured to store an electrical energy to be supplied to the speed governing control unit; and a generator (41, 73) configured to generate the electrical energy, wherein one of the permanent magnet and the coil is held by the balance, the speed governing control unit compares the clock signal and the vibration detection signal and performs the speed governing control of the balance by exerting an electromagnetic force on the permanent magnet, the electromagnetic force being generated by outputting a current to the coil, and characterized in that when a stored energy amount of the storage unit (44) is equal to or smaller than a predetermined value, the speed governing control unit (50) switches a state to a stop state where the speed governing control of the balance (30) is stopped.
  2. The mechanical watch (1) according to claim 1, further comprising a power switch (430) coupled between the coil (35) and a power-source line (VDD, VSS) configured to supply a current to the coil, wherein the speed governing control unit (50) switches the state to the stop state by turning the power switch off.
  3. The mechanical watch (1) according to claim 2, wherein the power-source line (VDD, VSS) includes a first power-source line (VDD), and a second power-source line (VSS) of a potential different from that of the first power-source line, the power switch (430) includes: a first switch (431) coupled between a first terminal (351) of the coil (35) and the first power-source line, a second switch (432) coupled between a second terminal (352) of the coil and the first power-source line, a third switch (433) coupled between the first terminal of the coil and the second power-source line, and a fourth switch (434) coupled between the second terminal of the coil and the second power-source line, and the speed governing control unit (50) performs a control by switching between a speed governing state and the stop state, the speed governing state being a state where a speed of the balance is governed by controlling on and off of the first switch, the second switch, the third switch, and the fourth switch to control a direction of a current flowing through the coil, the stop state being a state where the first switch, the second switch, the third switch, and the fourth switch are controlled off and no current flows through the coil.
  4. The mechanical watch (1) according to claim 3, wherein the vibration detection unit (47) includes: the coil (35), and a detection circuit (52) coupled to the first terminal (351) and the second terminal (352) of the coil (35), and configured to detect a current flowing through the coil by the permanent magnet (36) moving relative to the coil along with a vibration of the balance (30) and the speed governing control unit (50) performs a control by switching among a vibration detection state, the speed governing state, and the stop state, the vibration detection state being a state where one of the first switch (431) and the second switch (432) is turned on, and the other of the first switch and the second switch, the third switch (433), and the fourth switch (434) are turned off, the speed governing state being a state where one of the first switch and the second switch and one of the third switch and the fourth switch are turned on, and the other of the first switch and the second switch and the other of the third switch and the fourth switch are turned off, the stop state being a state where the first switch, the second switch, the third switch, and the fourth switch are turned off.
  5. The mechanical watch (1) according to any one of claims 1-4, wherein the generator (41) is an electromagnetic generator including the permanent magnet (36) and the coil (35) and configured to generate power through a relative movement of the permanent magnet and the coil along with a vibration of the balance.
  6. The mechanical watch (1) according to any one of claims 1-4, wherein the generator (41) is a solar generator including a solar panel (65).
  7. The mechanical watch (1) according to claim 6, further comprising a light-transmitting case back (61), wherein the solar panel (65) generates power by receiving light transmitted through the case back.
  8. The mechanical watch (1) according to any one of claims 1-4, wherein the generator is an electromagnetic generator (73) including a power generation coil (733), a rotor (731), and a rotating mechanism configured to rotate the rotor.
  9. The mechanical watch (1) according to any one of claims 1-4, wherein the generator (73) includes a power generation coil (733) configured to generate power through electromagnetic induction with a magnetic field applied from outside.

Description

BACKGROUND 1. Technical Field The present disclosure relates to a mechanical watch including a balance. 2. Related Art JP-A-2020-52047 discloses a mechanical watch including a train wheel driven by a mechanical energy applied by a barrel including a spiral spring inside, a balance that governs the speed of the train wheel, and a control circuit that detects the motion of the balance with the sensor and measures the time draft of a sensor detection signal with respect to a digital reference signal output from an auxiliary oscillator including a crystal resonator and a watch circuit so as to activate the brake device in accordance with the time draft. In JP-A-2020-52047, the electrical energy generated by a thermoelectric element and/or a photovoltaic cell as an energy source is stored in a storage device, and the control circuit is driven with the stored electrical energy. In the mechanical watch disclosed in JP-A-2020-52047, when the voltage of the electrical energy stored in the storage device decreases, the speed governing control of the control circuit cannot be properly executed, which affects the operation of the balance serving as a mechanical resonator, and the time accuracy indicated by hands. EP 1241538 discloses a mechanical timepiece according to the invention, which includes a mainspring, a front train wheel and an escapement and speed control apparatus. The escapement and speed control apparatus includes a balance with hairspring, an escape wheel and pinion and a pallet fork. The mechanical timepiece according to the invention further includes a crystal oscillator constituting an oscillation source, an IC including a dividing unit for outputting a signal with respect to time by inputting an output signal outputted by oscillating the crystal oscillator and dividing the output signal, and an electricity storing member for operating the IC. The mechanical timepiece according to the invention further includes a rate detecting unit for detecting a rate of the mechanical timepiece and a balance power generation control unit constituted to control a period of rotational oscillation of the balance with hairspring based on a divided signal divided by the dividing unit and an operational state signal indicating the rate detected by the rate detecting unit, and to generate power by the rotational oscillation of the balance with hairspring. US 11422510 is also relevant. SUMMARY A mechanical watch according to the invention is defined in claim 1. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view illustrating a mechanical watch of an embodiment.FIG. 2 is a block diagram illustrating a configuration of the mechanical watch.FIG. 3 is a schematic perspective view illustrating a configuration of a main part of the mechanical watch.FIG. 4 is an exploded perspective view illustrating a balance, a pallet and an escape wheel of the mechanical watch.FIG. 5 is a side view illustrating a permanent magnet and a coil of the balance of the mechanical watch.FIG. 6 is a plan view illustrating a balance wheel, a permanent magnet and a coil of the mechanical watch.FIG. 7 is an explanatory view of an operation of the balance of the mechanical watch.FIG. 8 is a circuit block diagram illustrating a configuration of an electronic speed governing apparatus of the mechanical watch.FIG. 9 is a circuit diagram illustrating a configuration of a speed governing unit of the mechanical watch.FIG. 10 is a waveform diagram illustrating a vibration detection waveform of the mechanical watch.FIG. 11 is a flowchart illustrating a speed governing control of the mechanical watch.FIG. 12 is a flowchart illustrating a balance speed governing control of the mechanical watch.FIG. 13 is a timing diagram illustrating a speed governing control signal for the balance speed governing control of the mechanical watch.FIG. 14 is a graph illustrating a barrel torque curve of the mechanical watch.FIG. 15 is a schematic sectional view illustrating a mechanical watch of a modification.FIG. 16 is a perspective view illustrating an electromagnetic generator of another modification.FIG. 17 is a schematic perspective view illustrating a generator of another modification. DESCRIPTION OF EMBODIMENTS A mechanical watch 1 of an embodiment is described below with reference to the drawings. As illustrated in FIG. 1, the mechanical watch 1 includes a case 2, a dial 3, an hour hand 4, a minute hand 5, a seconds hand 6, a crown 7, and a date indicator 8. As illustrated in FIG. 2, the mechanical watch 1 includes a mechanical movement 10, and an electronic speed governing apparatus 40 that improves the accuracy of the mechanical movement 10. In the mechanical movement 10, the configuration of a balance 30 is mainly changed compared with mechanical movements of common mechanical watches. As also illustrated in FIG. 3, the mechanical movement 10 includes a barrel complete 11 composed of a power spiral spring 12, a barrel gear 13, a barrel stem 14 and a barrel lid. The s