Oscillator Balance Wheel with Guide-Walled Weight Retention
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Solution Overview
Problem
Existing balance wheels in watchmaking face challenges in maintaining stable inertia over time due to manufacturing inaccuracies and wear, particularly with adjustable moment of inertia designs that require precise thread interactions, leading to high costs and potential unbalances.
Innovation Solution
A balance wheel design featuring a rim with distributed adjustment weight retaining systems and a one-piece hub with a guide wall hole and relief pattern, utilizing precise manufacturing methods like LiGA or deep reactive ion etching to ensure precise positioning and minimize unbalance, allowing for stable inertia adjustment without the need for assembly-dependent components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional adjustable balance wheels with screwed weights are used, then the moment of inertia can be adjusted, but manufacturing precision and dimensional stability deteriorate due to thread wear and assembly inaccuracies
Solution Approach 1:
The balance wheel is divided into a fixed rim and movable weights that can be independently positioned. The weights are retained by a retaining system with guide wall holes and relief patterns that allow precise positioning without complex threaded connections, enabling adjustment while maintaining manufacturing precision.
Solution Approach 2:
The adjustment function is extracted from the rim structure and assigned to separate movable weights. This allows the rim to be a simple, precisely manufacturable component while the weights provide the adjustment capability, separating the precision requirement from the adjustability requirement.
2Reliability
If complex retaining structures with multiple components are used, then adjustment weights can be secured, but device complexity and manufacturing cost increase
Solution Approach 1:
The guide wall hole and relief pattern are integrated into a single retaining system structure formed as one piece. This merging of functions (guidance and retention) into a single component reduces the number of parts while maintaining reliable weight retention through the combined action of the guide walls and relief patterns.
Solution Approach 2:
The retaining system structure serves multiple functions simultaneously: it provides guide wall holes for axial guidance, incorporates relief patterns for radial retention, and acts as a unified structural element. This multi-functionality reduces the need for separate components while ensuring reliable weight retention.
3Strength
If flexible blades with mass are used for axial return, then thread tightening is achieved, but balance unbalance occurs due to the mass of the blades
Solution Approach 1:
The axial return function is extracted from massive flexible blades and transferred to the lightweight relief pattern structure. The relief patterns provide the necessary tightening force through their geometric configuration without adding significant mass that would cause balance unbalance, as they are integrated into the thin retaining system structure.
Solution Approach 2:
The mechanism for achieving axial return changes from relying on the mass and flexibility of thick blades to utilizing the geometric configuration and elastic deformation of thin relief patterns. This parameter change (from mass-dependent to geometry-dependent) reduces the added mass while maintaining the tightening function.
4Manufacturing precision
If high dimensional requirements are imposed on threads, then adjustment precision is maintained, but manufacturing cost increases substantially
Solution Approach 1:
The relief patterns are designed as simple, easily manufacturable features that do not require high-precision threading operations. By using this simpler retaining mechanism, the patent accepts that the retention structure itself is less complex, thereby reducing manufacturing cost while still achieving precise weight positioning through the guide wall holes and relief pattern interaction.
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 design achieves stable and precise inertia adjustment with reduced manufacturing costs, minimal unbalance, and enhanced robustness, facilitating automated production and maintaining high-quality operation while allowing for mass distribution optimization.
Implementation Method 1
at least one spring portion positioned such that elastic deformation of that spring portion occurs when screwing the flyweight rod into the first retaining system
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
An oscillator balance wheel (1) for a watch movement comprises a rim (13), retaining regulating weights (2) distributed along the rim (13), and a first one-piece part (3) defining a hub (5) intended to be threaded onto a pivoting shaft. A second part (4) fixed to the first part (3) defines the rim (13).At least one of the first retention systems comprises: - a guide-walled hole (15) that forms at least a portion of a passage for a weight rod and is located in the sleeve (13), - at least one raised motif (35) that at least partially borders the passage for the weight rod and is capable of engaging a thread (25) on the weight rod when the weight rod is inserted into the guide-walled hole (15), - at least one spring-forming portion (11) positioned such that an elastic deformation of this spring-forming portion (11) occurs when the weight rod is screwed into the first retention system and is accompanied by tightening that produces a resistance that must be overcome to change the degree of screwing of the weight rod into the first retention system. The first part (3) defines the spring-forming portion (11) of the first retention system (28).The invention also relates to a method for manufacturing an oscillator balance wheel (1).