Watch Movement Rotating Mobile With Conical Bearings for Stable Oscillation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional shock absorber bearings in watch movements experience variations in friction torque due to changes in the orientation of the mobile relative to gravity, leading to variations in oscillation amplitude and potential walking differences, which existing solutions like pre-stressed systems with springs increase friction and are difficult to manufacture consistently.
Innovation Solution
A mobile system with a rotating mobile and bearings featuring a conical cavity and pivot design with a minimum contact angle of less than or equal to 30°, ensuring consistent friction torque regardless of orientation by minimizing lever arm differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shock absorber bearing with a domed stone and counter-pivot stone is used, then the pivot is protected from impact, but friction torque varies with orientation relative to gravity
Solution Approach 1:
The invention changes the geometric parameters of the bearing cavity from a domed shape to a conical shape with a specific semi-vertical angle (≤30°). This parameter change ensures that the contact point between the pivot and cavity始终保持 at a consistent radial distance from the pivot axis, regardless of the mobile's orientation relative to gravity, thereby eliminating friction torque variation while maintaining shock absorption capability
Solution Approach 2:
The conical cavity design creates an equipotential condition where the friction torque remains constant across all orientations. By carefully selecting the cone angle, the system ensures that the gravitational force always acts through the same lever arm relative to the pivot axis, making the friction torque independent of orientation, similar to how equipotential surfaces have constant potential energy
2Force
If a pre-stressed spring-mounted bearing is used to center the pivot in the cavity, then the lever arm of friction force is minimized, but the spring increases weight and friction
Solution Approach 1:
The invention extracts and eliminates the spring component from the bearing system. Instead of using a pre-stressed spring-mounted bearing to center the pivot, the design relies on the geometric configuration of the conical cavity itself to maintain proper pivot alignment and minimize friction lever arm, thereby removing the additional weight and friction introduced by the spring
Solution Approach 2:
The invention uses a conical surface (a type of curved surface) for the cavity instead of a flat or domed surface. This curved conical geometry naturally guides and centers the pivot during rotation, maintaining optimal contact conditions without requiring additional centering mechanisms like springs, thus reducing both weight and friction
3Force
If the bottom of the conical cavity is polished to ensure good surface condition, then friction is reduced, but the cavity bottom is difficult to access by polishing means
Solution Approach 1:
The invention segments the cavity geometry into an accessible upper portion and a deeper lower portion. The conical shape with its specific angle allows the critical contact zone to be located in the upper, easily accessible region that can be effectively polished and finished, while the lower portion tapers to a point that is less critical for surface finish and harder to access, thus resolving the manufacturing accessibility issue
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 system reduces friction torque variations by maintaining consistent contact forces across different orientations, stabilizing the balance wheel's oscillation and preventing axis breakage through optimized contact angles and shapes.
Implementation Method 1
the friction torque on the axis due to the weight of the mobile varies depending on the orientation of the mobile relative to the direction of gravity
Implementation Method 2
The setting 3 is held in abutment against the bottom of a bearing block 5 by a damping spring 6 arranged to exert an axial stress on the upper part of the counter-pivot stone 4
Implementation Method 3
the pivots of a balance wheel's shaft are usually thin and the mass of the balance wheel is relatively high, the pivots can break under the effect of an impact in the absence of a shock-absorbing mechanism
Data Source
Figure 1~3
Figure 4~6
Figure 7~9
AI summary
The invention relates to a rotating moving part (10) of a watch movement, the part (10) comprising a rotating part, for example a balance wheel (13), a first and a second bearing (18, 20), in particular shock absorbers, for a first and a second pivot (15, 17) of the axis (16) of the rotating part, the part having a center of mass (G) at a position on its axis (16), the first bearing (18, 20) comprising a counter-pivot including a main body having a conical cavity (19) configured to receive the first pivot (17) of the axis (16) of the rotating part, the first pivot (17) being able to cooperate with the cavity (19) of the counter-pivot (22) in order to rotate within the cavity (19), at least one contact zone (29) between the first pivot (17) and the cavity (19) being generated, the normals of the contact zone (29) forming a minimum contact angle relative to the plane perpendicular to the axis (16) of the pivot (17), the minimum contact angle being less than or equal to 30°,preferably less than or equal to arctan12.