Timepiece Gear Train with Involute Gear for Stable Torque
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Solution Overview
Problem
The existing gear train mechanisms in timepieces face challenges in manufacturing and stability due to the complexity of tooth profiles defined by specific calculation formulas, leading to significant torque fluctuations during power transmission.
Innovation Solution
A gear train mechanism with a gear having an involute tooth profile and a pinion with a constant torque curve tooth profile, designed to maintain a substantially constant torque transmission throughout a significant portion of the meshing period, reducing manufacturing complexity and torque fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both gear and pinion have tooth profiles defined by specific calculation formulas to reduce torque fluctuation, then torque transmission stability is improved, but manufacturing complexity and difficulty increase significantly
Solution Approach 1:
The patent changes the tooth profile parameters by using an involute curve for the gear and a specifically designed curve for the pinion, optimizing the meshing characteristics to reduce torque fluctuation while maintaining manufacturability through standardization of the gear component
Solution Approach 2:
Instead of making both gear and pinion complex to achieve constant torque, the patent inverts the approach by making the gear simple (standard involute) and designing the pinion tooth profile specifically to compensate and achieve the constant torque transmission, thereby reducing overall manufacturing complexity
2Ease of manufacture
If gear and pinion use standard involute tooth profiles for ease of manufacture, then manufacturing complexity is reduced, but torque fluctuation during transmission increases
Solution Approach 1:
The patent applies different tooth profile qualities to different components: the gear uses a standard involute profile for ease of manufacture, while the pinion uses a specifically designed profile with optimized characteristics to reduce torque fluctuation, allowing each component to have the appropriate quality for its function
Solution Approach 2:
The patent modifies the pinion tooth profile parameters (such as pressure angle variation along the tooth height) to achieve reduced torque fluctuation, while keeping the gear parameters standard, thus balancing manufacturing ease with transmission stability
Data Source
AI summary
A gear train mechanism of a timepiece is formed by a gear having an involute tooth profile, which is easily manufactured, and a pinion that meshes with the gear. In order to reduce a fluctuation in torque to be transmitted, a gear train mechanism of a timepiece includes a gear including a tooth having a tooth profile of an involute curve and a pinion including a tooth meshing with the tooth of the gear to transmit and receive a torque, wherein the torque to be transmitted from the gear to the pinion is substantially constant at least in a part of a first half of a meshing period of the gear and the pinion.