Timepiece Gear Train with Constant-Torque Pinion Meshing
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Solution Overview
Problem
Existing gear train mechanisms in timepieces face challenges in manufacturing and stability due to complex tooth profile calculations and involute tooth profiles, 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, optimized for reduced torque fluctuations, is designed to enhance manufacturing ease and operational stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gear train mechanism uses a gear and pinion both having tooth profiles defined by a specific calculation formula to reduce torque fluctuation, then torque transmission stability is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent applies different tooth profile characteristics to different components: the gear has an involute tooth profile while the pinion has a modified tooth profile with adjusted pressure angle. This local differentiation allows each component to be optimized for its specific function while maintaining ease of manufacture through standardized gear cutting processes.
Solution Approach 2:
The patent modifies the pressure angle parameter of the pinion tooth profile relative to the gear tooth profile. By changing this geometric parameter, the patent achieves reduced torque fluctuation while maintaining compatibility with standard manufacturing processes for involute gears.
2Reliability
If a gear train mechanism uses a gear without an involute tooth profile to reduce torque fluctuation, then torque transmission stability is improved, but manufacturing ease is reduced
Solution Approach 1:
The patent maintains the involute tooth profile for the gear (which is easy to manufacture) while applying a modified profile only to the pinion. This selective application preserves manufacturing ease for the majority of the gear train while achieving the desired torque stability improvement.
3Ease of manufacture
If a gear train mechanism uses a gear with involute tooth profile and a pinion with modified tooth profile, then manufacturing ease is improved, but torque fluctuation may increase
Solution Approach 1:
The patent carefully adjusts the pressure angle parameter of the pinion tooth profile to achieve optimal torque transmission. By precisely controlling this geometric parameter within specific ranges, the patent maintains reduced torque fluctuation while utilizing standard involute gear manufacturing processes.
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 proposed gear train mechanism achieves a substantial constant torque transmission rate with reduced torque fluctuations, ensuring stable operation and improved manufacturing feasibility.
Implementation Method 1
a gear (10) including a tooth (11) having a tooth profile and a pinion (20) including a tooth (21) meshing with the tooth (11) of the gear (10) to transmit and receive a torque
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
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 (1) of a timepiece includes a gear (10) including a tooth (11) having a tooth profile of an involute curve and a pinion (20) including a tooth (21) meshing with the tooth (11) of the gear (10) to transmit and receive a torque, wherein the torque to be transmitted from the gear (10) to the pinion (20) is substantially constant at least in a part of a first half of a meshing period of the gear (10) and the pinion (20).