Publication
Tribological Approach to the Watch Movements
Publications associées (73)
Pivot, process for manufacturing such a pivot, oscillator comprising such a pivot, watch movement and timepiece comprising such an oscillator
Simon Nessim Henein, Loïc Benoît Tissot-Daguette
The present invention concerns a pivot comprising two assemblies, namely a central assembly (401) and a peripheral assembly (400). These two assemblies are mobile in rotation relative to each other around an axis of rotation (A). The pivot is characterized ...
2024Modeling of rough contact interfaces with trapped compressive liquid pockets
Jean-François Molinari, Guillaume Anciaux, Parissasadat Alavi, Julie Richard, Loris Rocchi
Boundary and mixed lubrication are usually used to reduce friction in sheet metal form- ing. In the boundary lubrication regime load is mainly carried by contacting asperities. Therefore, the tribological problem can be solved in the dry case using a geome ...
2023Modeling the origins of adhesive wear across scales
Friction and wear occur at every interface between solid materials.In the design of mechanical devices, it is desirable to be able to quantify and control the amount of friction and wear, as well as predict their evolution with time. ``Tribology'' is the s ...
EPFL2022Triple Crossed Flexure Pivot Based on a Zero Parasitic Center Shift Kinematic Design
Simon Nessim Henein, Etienne Frédéric Gabriel Thalmann
Thanks to their absence of play, absence of contact friction and possible monolithic fabrication, flexure pivots offer advantages over traditional bearings in small-scale, high accuracy applications and environments where lubrication and wear debris are pr ...
2022The Role of Geometrical Parameters in the Lubrication of the Swiss Lever Escapement
The lubrication regimes of a contact pair escapement-ruby pallet of a Swiss lever escapement have been investigated combining the theory of fluid lubrication with a well-established kinematic and inverse dynamic multibody model. The kinematic analytical re ...
2021Adhesive wear regimes on rough surfaces and interaction of micro-contacts
Jean-François Molinari, Son-Jonathan Pham-Ba
We develop an analytical model of adhesive wear between two unlubricated rough surfaces, forming micro-contacts under normal load. The model is based on an energy balance and a crack initiation criteria. We apply the model to the problem of self-affine rou ...
2021A Simple Mechanistic Model for Friction of Rough Partially Lubricated Surfaces
Jean-François Molinari, Tobias Brink, Gianluca Costagliola, Julie Richard
We report experimental measurements of friction between an aluminum alloy sliding over steel with various lubricant densities. Using the topography scans of the surfaces as input, we calculate the real contact area using the boundary element method and the ...
2021A parameter-free mechanistic model of the adhesive wear process of rough surfaces in sliding contact
Jean-François Molinari, Tobias Brink, Lucas Henri Galilée Frérot
In order to develop predictive wear laws, relevant material parameters and their influence on the wear rate need to be identified. Despite decades of research, there is no agreement on the mathematical form of wear equations and even the simplest models, s ...
2021Optical measurement method for mechanical time base characterization
Simon Nessim Henein, Etienne Frédéric Gabriel Thalmann
The recent adoption of silicon components by the mechanical watch industry has triggered the search for new time bases to advantageously replace the traditional balance and hairspring oscillator. In particular, flexure-based oscillators manufactured in sil ...
2021A lubricated tribocorrosion model incorporating surface roughness
This study presents an improvement of an existing tribocorrosion model developed for passive CoCrMo alloys. This model is based on an empirical formalism established by Duncan Dowson in his pioneering works on the relation between wear and elasto-hydrodyna ...
2021