Timepiece Balance Actuator With Magnetic Rest Position Stabilization
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Solution Overview
Problem
Existing timepiece actuators with electromagnetic systems are prone to undesired movements due to impacts or accelerations, causing parasite braking pulses on the balance-spring, which disrupt the timepiece's operation and frequency regulation.
Innovation Solution
Incorporating an actuator with a flexible member formed by an elastic element and a magnetic element that interacts with a permanent magnet, providing a stable rest position by generating a magnetic force opposing the electromagnetic force, thus reducing the risk of undesired movements and parasite pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a flexible blade is used in the actuator, then the device can be actuated by electromagnetic system, but the flexible blade easily undergoes undesired movements from rest position due to impacts or accelerations
Solution Approach 1:
The patent introduces a magnetic return force that acts as a counterbalancing force to the elastic return force. This magnetic force, generated by the interaction between the permanent magnet and the flexible blade, provides an additional stabilizing effect that counteracts disturbing forces such as impacts and accelerations, thereby improving rest position stability without compromising actuation capability.
Solution Approach 2:
The patent modifies the force characteristics of the flexible blade by introducing a magnetic component. The magnetic force parameter is added to the mechanical elastic force, creating a composite force field that changes the overall behavior of the flexible element. This allows the system to maintain stability over a broader range of operating conditions while preserving the necessary actuation range.
2Reliability
If the elastic force is increased to stabilize the rest position, then undesired movements are reduced, but the electromagnetic force required for actuation must be even stronger
Solution Approach 1:
The magnetic return force acts as a supplementary stabilizing force that works alongside the elastic force. Rather than relying solely on increasing elastic force (which would require proportionally stronger electromagnetic force for actuation), the magnetic component provides additional rest position stability, thereby reducing the power requirement for the electromagnetic actuation system.
Solution Approach 2:
The patent creates a composite force system combining magnetic and elastic properties in the flexible blade. This composite approach leverages the advantages of both force mechanisms: the elastic force provides baseline stability while the magnetic force enhances rest position holding capability, together creating a more efficient system that requires less electromagnetic power for actuation.
3Ease of operation
If the flexible blade is mechanically returned towards rest position, then it can recover from actuation, but the mechanical return force is weak near rest position causing vibrations
Solution Approach 1:
The magnetic return force provides a stabilizing counterbalancing effect that compensates for the weakness of the mechanical elastic force near the rest position. This magnetic component acts as a virtual counterweight that prevents the flexible blade from vibrating or undergoing undesired movements when close to rest, thereby eliminating the instability issue without compromising the mechanical return capability.
Solution Approach 2:
The magnetic interaction serves as an intermediary force mechanism that bridges the gap between the mechanical elastic force and the rest position stability requirement. The magnetic field acts as a mediator that provides additional holding force near the rest position, preventing vibrations and undesired movements while allowing the mechanical elastic force to continue providing the primary return capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution stabilizes the flexible member's rest position, minimizing the risk of parasite pulses on the balance-spring, ensuring accurate frequency regulation and operation of the timepiece.
Implementation Method 1
the actuator further comprises a magnetic element that is arranged in such a way as to be able to interact with the permanent magnet to engender between them a magnetic force that is exerted on the mechanical element when the latter is in the rest position
Implementation Method 2
an electromagnetic system formed by a permanent magnet and a coil... to engender an electromagnetic force between this coil and the permanent magnet
Implementation Method 3
the flexible member is formed at least partially by an elastic element that is arranged in such a way as to engender a mechanical force of return of the mechanical element in the direction of the rest position
Data Source
AI summary
A timepiece (2) includes an actuator, which applies braking pulses to the balance, which has an electromechanical device (6) and an electric control circuit (8). The device (6) includes a flexible member (16), formed by an elastic blade (20) and a mechanical element (22) defining a braking pad, and an electromagnetic system (10) formed by a coil carried by the flexible member and by a permanent magnet rigidly connected to a support (18) of the electromechanical device. When an electric pulse is provided to the coil, an electromagnetic force of repulsion is engendered between the coil and the permanent magnet so the mechanical element moves to a position of contact with the balance. To stabilise the rest position of the flexible member, a magnetic element (26) is rigidly connected to the coil to exert a magnetic return force complementary to the force of the elastic blade is provided.