Flexure Bearing Oscillator Angular Stroke
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Solution Overview
Problem
Mechanical timepiece oscillators with flexure bearings face limitations in angular stroke, which makes them incompatible with conventional escapement mechanisms and affects isochronism and position insensitivity.
Innovation Solution
The development of a mechanical oscillator with flexure bearings that achieve a large angular stroke and isochronism by optimizing the vertex angle and strip ratio of the flexible strips, allowing compatibility with existing escapement mechanisms and maintaining high quality factor and position insensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flexure bearings are used in mechanical timepiece oscillators, then the quality factor increases due to reduced pivot friction, but the angular stroke is limited to around 10° to 20° which is incompatible with conventional escapement mechanisms
Solution Approach 1:
The oscillating mass is divided into two separate masses that can oscillate independently with different amplitudes. The first oscillating mass has a large angular stroke compatible with escapement mechanisms, while the second oscillating mass maintains the high quality factor benefits of flexure bearings. This segmentation allows each mass to optimize for its specific function.
Solution Approach 2:
The invention transitions from a single-axis oscillation to a coupled two-axis oscillation system. The first oscillating mass oscillates primarily in one plane with large amplitude, while the second oscillating mass oscillates in a different plane or axis, creating a multi-dimensional oscillation pattern that satisfies both large stroke and high quality factor requirements.
2Adaptability or versatility
If the angular stroke of flexure bearings is increased to be compatible with escapement mechanisms, then compatibility with conventional mechanisms is achieved, but isochronism and position insensitivity deteriorate
Solution Approach 1:
The oscillation function is segmented between two separate oscillating masses. The first mass handles the large angular stroke required for escapement compatibility, while the second mass is designed with precise flexure characteristics to maintain isochronism and position insensitivity. This functional segmentation allows each component to optimize for its specific performance requirement.
Solution Approach 2:
The second oscillating mass acts as an intermediary element that couples the large-stroke first mass with the escapement mechanism while maintaining precise timing characteristics. It mediates between the requirement for large angular displacement and the requirement for precise isochronous oscillation.
3Ease of operation
If a single oscillating mass with large angular stroke is used, then compatibility with escapement mechanisms is achieved, but the quality factor decreases due to increased friction and energy loss
Solution Approach 1:
The oscillation function is divided between two separate masses where the second oscillating mass serves as the primary quality factor contributor with its precisely engineered flexure bearings, while the first oscillating mass provides the necessary large angular stroke for escapement interaction. This segmentation isolates the high-precision flexure elements from the large-displacement requirements.
Solution Approach 2:
The invention merges two oscillating masses with different functional characteristics into a single coupled oscillation system. The first mass provides large stroke capability while the second mass provides high quality factor, and their combined operation achieves both objectives simultaneously through elastic coupling.
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 enables a mechanical oscillator with a large angular stroke greater than 30°, compatible with all types of mechanical escapements, while maintaining high quality factor and isochronism, thus overcoming the limitations of previous flexure bearing designs.
Implementation Method 1
a flexure bearing with at least two first flexible strips which support said solid inertial element and are arranged to return it to a rest position
Data Source
AI summary
A mechanical timepiece oscillator includes, between a support and an inertial element, a flexure bearing with flexible strips crossed in projection, including, superposed, an upper level that includes, between an upper support and an upper inertial element, an upper primary strip in a first direction and an upper secondary strip in a second direction, and a lower level that includes, between a lower support and a lower inertial element, a lower primary strip in the first direction and a lower secondary strip in the second direction. The upper level and lower level include, between the support and the upper or respectively lower support, a translational table with an elastic connection along one or two axes of freedom in the oscillation plane, of lower stiffness than that of each flexible strip.