Micromechanical Damping Structure With Viscoelastic Shear Layers

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Solution Overview

Problem

Existing shock and vibration damping devices in watchmaking are inadequate for absorbing kinetic energy from shocks and vibrations, particularly in radial and axial directions, leading to potential damage of fragile silicon components, and they are often bulky or ineffective in repositioning the movement after a shock.

Innovation Solution

A damping device comprising flexible elements made from materials like silicon, ceramics, or metals, combined with viscoelastic dissipative layers, designed to absorb shocks and vibrations by shearing the dissipative layer, which dissipates energy and returns the device to its original position without plastic deformation, ensuring effective damping and precise repositioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If elastic means (springs) are used to protect the bearing against shocks, then the bearing is protected against axial shocks, but the kinetic energy of the shock is not absorbed and is transmitted to the rest of the movement

Engineering Contradiction:
Improveprotection against axial shocksVSAvoidkinetic energy transmission
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent combines elastic blades (made of elastic material) with a viscous damping substance (polymer or gel) to create a composite damping device. The elastic blades provide structural support and shock protection, while the viscous substance absorbs kinetic energy through internal friction and shear deformation. This composite structure resolves the contradiction by maintaining the protective function while adding energy absorption capability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the physical state and properties of the damping medium from purely elastic to viscoelastic by introducing a viscous component. The viscous substance exhibits shear-thinning behavior and energy dissipation characteristics that differ from conventional elastic materials, enabling kinetic energy absorption while maintaining protective functions.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If conventional shock absorbers are used, then shocks are absorbed, but the devices are bulky and not suitable for high-precision micromechanical systems

Engineering Contradiction:
Improveshock energy absorptionVSAvoiddevice size
Core Design Contradiction:
Loss of energyVSVolume of moving object

Solution Approach 1:

The patent employs thin elastic blades instead of bulky mechanical shock absorbers. These blades are flexible yet structurally sound, providing shock protection in a minimal space. The viscous damping substance is applied as a thin layer or coating between the blade arms, maintaining compact dimensions while delivering effective energy absorption. This approach enables integration into space-constrained micromechanical systems.

Inventive Principle:
Principle #30Flexible shells and thin films

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 effectively absorbs shocks and vibrations in all directions, dissipates kinetic energy, and integrates seamlessly into watch components, preventing damage to fragile parts while maintaining precise repositioning and being compact enough for high-precision micromechanical systems.

Implementation Method 1

a layer 1c said dissipative extending between said flexible strips 1a and 1b and being integral, over all or part of its length, with said flexible strips 1a and 1b. The dissipative layer 1c is obtained in a viscoelastic material

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

dissipates energy by shearing of the dissipative layer

Methodology Applied
Scientific EffectShear stress: Shear Stress

Implementation Method 3

The flexible strips 1a and 1b are obtained from an elastic material so that the repositioning of the damping device in its initial rest position is perfect, i.e. there is no plastic deformation

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3076245B1Damping device, in particular for micromechanical clock component
Publication Date: 2021.03.17 CSEM CENTRE SUISSE D ELECTRONIQUE ET DE MICROTECHNIQUE SA
  • EP3076245B1 patent drawingFigure 1~2
  • EP3076245B1 patent drawingFigure 3~4
  • EP3076245B1 patent drawingFigure 5

AI summary

The present invention relates to a shock and/or vibration damping device (1) comprising at least one flexible element (1a, 1b) capable of deforming under the effect of a stress; said device is remarkable in that it comprises at least one so-called dissipative layer (1c) obtained in a material having a shear modulus lower than the shear modulus of the flexible element (1a, 1b), a damping factor higher to the damping factor of said flexible element (1a, 1b), and secured at least partially to said flexible element (1a, 1b) such that a bending of the flexible element (1a, 1b), under the effect of a stress, provides shearing of the dissipative layer (1c) making it possible to dissipate at least part of the energy of said stress. Another object of the invention relates to a method of manufacturing said damping device.