Timepiece Movement Reference Load Units for Hand Position Detection
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Solution Overview
Problem
Existing timepiece mechanisms face difficulties in accurately detecting the reference position of an indicating hand due to high reduction ratios in wheel gears, leading to inconsistent load fluctuations and potential misalignment of the indicating hand.
Innovation Solution
A timepiece movement incorporating a stepping motor with a train wheel group featuring a first and second wheel gear, where the second wheel gear has a second reference load unit that causes a higher frequency load fluctuation, allowing for accurate detection by combining it with the lower frequency fluctuation from the first reference load unit, ensuring precise alignment of the indicating hand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a wheel gear with high reduction ratio is used to cause load fluctuation in the rotor, then the indicating hand position can be detected, but the load fluctuation occurs over multiple steps making accurate detection difficult
Solution Approach 1:
The patent divides the single load fluctuation detection into multiple segmented detections by introducing two reference load units at different positions in the train wheel group. The first reference load unit detects load fluctuation at a higher reduction ratio position, while the second reference load unit detects at a lower reduction ratio position. This segmentation allows the system to identify the reference position through multiple discrete detection points rather than relying on a single extended fluctuation period.
Solution Approach 2:
The second reference load unit acts as an intermediary detection mechanism that provides additional information about the rotor's rotational position. By detecting load fluctuation at an intermediate stage in the train wheel group (with lower reduction ratio), it provides a reference signal that helps determine the complete reference position more accurately and quickly than the first reference load unit alone.
2Measurement precision
If a single reference load unit is used, then the structure remains simple, but accurate reference position detection cannot be achieved due to extended load fluctuation period
Solution Approach 1:
The detection function is segmented into two separate reference load units positioned at different locations in the train wheel group. Each unit provides a distinct load fluctuation signal that, when combined, enables precise reference position detection without requiring a single complex reference mechanism.
Solution Approach 2:
Both reference load units serve the universal function of detecting load fluctuation to determine rotor position, but they operate at different reduction ratios to provide complementary information. This multi-functionality approach allows the system to achieve accurate detection while maintaining structural simplicity by using standard wheel gear components.
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
This configuration enables accurate detection of the reference position of the indicating hand by enhancing the frequency and consistency of load fluctuations, improving the reliability of hand position determination without increasing the number of wheel gears or altering the existing train wheel configuration.
Implementation Method 1
a stepping motor 20A, 20B having a rotor 22
Implementation Method 2
a third wheel gear 42a having a first reference load unit 60A disposed to mesh with the first wheel gear 34b so that a load received by the rotor 22 fluctuates
Data Source
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AI summary
A timepiece includes a first motor having a rotor for rotating a hour hand, and a first train wheel group having a wheel gear rotating based on rotation of the rotor. The first train wheel group includes a third intermediate hour pinion, a first intermediate hour pinion, a twenty four hour wheel gear having a first reference load unit disposed to mesh with the third intermediate hour pinion so that a load received by the rotor fluctuates in a case where the twenty four hour wheel gear meshes with the third intermediate hour pinion, and rotating at a first reduction ratio with respect to the rotor, and a second intermediate hour wheel gear having a second reference load unit disposed to mesh with the first intermediate hour pinion so that the load received by the rotor fluctuates in a case where the second intermediate hour wheel gear meshes with the first intermediate hour pinion, and rotating at a second reduction ratio lower than the first reduction ratio with respect to the rotor.