Accuracy stabilization device for clocks and mechanical clocks equipped therewith

Abstract

The object of the present invention is to provide a timekeeping accuracy stabilization device that can stabilize the rate over a long period of time with extremely low power consumption, without directly injecting mechanical vibrations into the balance wheel, while utilizing an external reference. [Solution] A precision stabilization device for a mechanical watch, comprising: a detection means for detecting the motion state of the balance wheel; an actuator driven at twice the natural frequency of the balance wheel based on the output of the detection means, which periodically changes the physical parameters of a movable member supporting the balance wheel; and a control circuit that uses an external reference oscillator as a time standard and adjusts the average rate of the balance wheel by slightly correcting the drive phase or duty cycle of the actuator.

Claims

1. In a precision stabilization device for mechanical watches, a) A detection means for detecting the motion state of the balance wheel, b) An actuator driven at twice the natural frequency of the balance wheel based on the output of the detection means, which periodically changes at least one physical parameter selected from the position, stiffness, mass distribution, or damping coefficient of the movable member supporting the balance wheel, c) A control circuit that uses an external reference oscillator as a time standard and adjusts the average rate of the balance wheel by making small corrections to the drive phase or duty cycle of the actuator, The apparatus is characterized by having a mechanism that does not directly convert the signal of the external reference oscillator into mechanical vibration and transmit it to the balance wheel.

2. The apparatus according to claim 1, characterized in that the actuator is at least one selected from a piezoelectric element, a magnetostrictive element, an electrostatic actuator, a shape memory alloy actuator, an electromagnetic coil, or a micromachine actuator.

3. The apparatus according to claim 1 or 2, characterized in that the control circuit minimizes at least one drive parameter selected from voltage, current, force, or pulse width to the actuator when the amplitude of the balance wheel is within a set range, and maintains the amplitude of the balance wheel by increasing the drive parameter only when the amplitude is outside the set range.

4. The apparatus according to any one of claims 1 to 3, wherein the control circuit calculates the phase difference between the external reference oscillator and the balance wheel motion, and corrects the average rate by slightly advancing or delaying the drive signal of the actuator according to the phase difference, but does not substantially change the total amount of kinetic energy supplied to the balance wheel by the actuator.

5. The apparatus according to any one of claims 1 to 4, wherein the actuator is positioned between the cap jewel supporting the end of the balance wheel shaft and the bearing jewel, or on the upper surface of the bearing jewel, and the actuator also serves as a shock absorber by interposing an elastic layer on at least one surface of the actuator.

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