Timepiece Balance Pivot Guide Bearing with Constant Friction Torque

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Solution Overview

Problem

Conventional balance wheel pivoting devices exhibit varying friction levels based on the watch's position, leading to differences in oscillation amplitude and rate, which affect the accuracy of timepieces.

Innovation Solution

A guide bearing with flexible blades or protrusions that exert a constant radial force on the resonator shaft, regardless of the watch's position, using elastic deformation to maintain consistent friction and minimize torque variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional balance wheel pivoting devices are used, then the structure is simple, but friction varies significantly with watch position leading to poor chronometric accuracy

Engineering Contradiction:
Improvechronometric accuracyVSAvoidbearing structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs flexible blades instead of rigid traditional jewels, allowing the bearing structure to dynamically adapt to gravitational forces in different positions. The blades flex to maintain optimal contact between the balance shaft and bearing surface, ensuring consistent friction characteristics whether the watch is held horizontally or vertically, thereby resolving the position-dependent accuracy issue without requiring complex multi-component assemblies

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the physical state and mechanical properties of the bearing material by using elastomeric or flexible materials with specific durometer ranges (40-90 Shore A). This parameter change allows the bearing to deform elastically under load, maintaining constant contact pressure and friction torque across different gravitational orientations, thus improving chronometric accuracy while keeping the overall structure relatively simple

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If rigid jewel bearings are used, then manufacturing is easy, but friction torque varies with watch position reducing oscillation consistency

Engineering Contradiction:
Improvefriction torque consistencyVSAvoidbearing manufacturing complexity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent transforms the bearing from a rigid jewel with fixed geometric parameters to a flexible elastomeric component with programmable durometer properties. By selecting materials within specific hardness ranges and designing blades with controlled flexibility, the bearing maintains stable friction torque across position changes. The manufacturing process uses injection molding or similar techniques to precisely control material distribution and blade geometry, achieving friction consistency without excessive manufacturing complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite construction combining flexible elastomeric blades with rigid mounting structures. The elastomeric portion (with specific durometer properties) provides position-independent friction characteristics, while the rigid frame or bridge provides structural support. This composite approach enables friction torque stability across different watch positions while maintaining ease of manufacturing through modular assembly

Inventive Principle:
Principle #40Composite materials

3Reliability

If flexible blades are used to maintain constant friction, then chronometric performance improves, but device complexity increases

Engineering Contradiction:
Improveoscillation quality consistencyVSAvoidbearing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The flexible blades are designed to dynamically respond to gravitational loading in different positions, automatically adjusting their curvature and contact pressure. This dynamic adaptation ensures constant friction torque and reliable oscillation quality without requiring external control mechanisms, active components, or complex adjustment systems. The reliability improvement comes from the inherent dynamic behavior of the elastomeric material rather than added complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The flexible blade bearing serves multiple functions simultaneously: it provides rotational support, maintains constant friction torque, absorbs positional variations, and ensures consistent oscillation quality all through a single integrated structure. This multi-functionality achieves reliable chronometric performance without requiring separate components for each function, thereby limiting the increase in device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 ensures consistent oscillation quality factors and improved chronometric performance by maintaining a constant friction torque across different positions, reducing rate differences and enhancing timepiece accuracy.

Implementation Method 1

using elastic deformation to maintain consistent friction and minimize torque variations

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The solution ensures consistent oscillation quality factors and improved chronometric performance by maintaining a constant friction torque across different positions

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3382472B1Guide bearing of a timepiece balance pivot
Publication Date: 2025.08.20 ROLEX SA
  • EP3382472B1 patent drawingFigure 1~2
  • EP3382472B1 patent drawingFigure 3~5
  • EP3382472B1 patent drawingFigure 6~8

AI summary

Bearing (1a) for guiding along an axis of a clockwork shaft, in particular a bearing for a portion of a shaft of a clockwork resonator, comprising at least one support element (13a) arranged to exert, radially to the axis or substantially radially to the axis, an action on the shaft, in a permanent manner.