Electronic Timepiece Movement With Slits for Magnetic Field Redirection
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Solution Overview
Problem
The increase in size of magnetic shielding plates to cover multiple stepping motors in electronic timepieces leads to unnecessary exposure to external magnetic fields, increasing magnetism flow and costs.
Innovation Solution
A single large magnetic shielding plate is used to cover multiple stepping motors, with strategically placed slits or holes to redirect external magnetic fields away from the coils, and the plate also serves as a structural support for other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the size of the magnetic shielding plate is increased to cover multiple stepping motors, then the number of magnetic shielding plates is reduced and costs are lowered, but the plate is exposed to more external magnetic fields resulting in increased magnetism flow
Solution Approach 1:
The magnetic shielding plate is divided into multiple regions with different magnetic shielding properties. Specifically, the plate includes a first region with high magnetic shielding performance covering the stepping motor, and a second region with lower magnetic shielding performance covering non-sensitive components. This segmentation allows the plate to provide targeted protection where needed while reducing overall magnetism accumulation.
Solution Approach 2:
Different portions of the magnetic shielding plate are assigned different magnetic shielding characteristics based on local requirements. The area over the stepping motor maintains strong magnetic shielding, while areas over non-magnetic components use reduced shielding material or different material properties, optimizing both protection and cost efficiency.
2Device complexity
If the size of the magnetic shielding plate is increased to serve as a bridge supporting components, then the need for separate bridges is eliminated and costs are reduced, but unnecessary areas are exposed to external magnetic fields
Solution Approach 1:
The magnetic shielding plate performs multiple functions simultaneously: it shields the stepping motor from magnetic fields, supports various movement components as a bridge structure, and provides mechanical stability. This multi-functionality eliminates the need for separate bridge components while maintaining effective magnetic shielding where required.
Solution Approach 2:
The plate is segmented into functional zones: a magnetic shielding zone over the stepping motor and structural support zones over other components. This allows the same plate to fulfill both shielding and structural roles without exposing sensitive areas to unnecessary magnetic fields.
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
Reduces magnetic influence on the stepping motors by redirecting external magnetic fields, thereby minimizing the need for multiple shielding plates and lowering costs.
Implementation Method 1
A single large magnetic shielding plate is used to cover multiple stepping motors, with strategically placed slits or holes to redirect external magnetic fields away from the coils
Data Source
Figure 1
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AI summary
To lower magnetic influence on a stepping motor covered by a magnetic shielding plate in an electronic timepiece and a movement, a movement (3) of an electronic timepiece (1) includes a stepping motor (10) having a rotor (13), a stator (12), and a coil (11) in which a conductive wire is wound around a coil winding core (11a); and a magnetic shielding plate (50) that covers at least a part of the stepping motor (10), wherein the magnetic shielding plate (50) includes slits (51), (52) as magnetic flow changing portions that change magnetic flows which are directed toward the coil winding core (11a) to magnetic flows which are not directed toward the coil winding core (11a), and the slits are formed in portions of the magnetic shielding plate, which correspond to extended lines (16a), (16b) from both end portions (11c), (11d) of the coil winding core (11a), respectively, to intersect with the extended lines (16a), (16b).