Meter Unit Braking Spring Integration for Thin Profile Stability
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Solution Overview
Problem
Existing meter device rotation shaft support structures face issues with permanent deformation due to resin springs, leading to increased minute swing movements and unsuitability for thin structures, especially when gears are stacked vertically.
Innovation Solution
A meter unit with a step motor, gear, and rotation shaft, featuring a braking spring accommodated in a recessed portion of the gear, where the spring is constantly pressed by a case component to maintain stability and prevent deformation, ensuring smooth rotation and light guide performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin spring is used to support the rotation shaft, then the minute swing movement is suppressed initially, but the spring deforms permanently over time due to fatigue, causing the suppression effect to deteriorate
Solution Approach 1:
The patent changes the material parameter from resin to metal (specifically phosphor bronze), which fundamentally alters the fatigue resistance and elastic properties of the spring, allowing it to maintain its support function throughout the service life
Solution Approach 2:
The patent replaces the durable but deforming resin spring with a metal spring that can be replaced if needed, though in practice the metal spring provides long-term durability without permanent deformation
2Ease of operation
If a leaf spring is mounted between the gear and case to support the rotation shaft, then the rotation is smoothed, but a boss must be added to the rotation shaft, increasing the thickness of the case
Solution Approach 1:
The patent merges the leaf spring directly with the gear body by forming it as an integral part of the gear, eliminating the need for a separate boss on the rotation shaft and reducing the overall case thickness
Solution Approach 2:
The gear body serves dual functions: transmitting torque and providing support for the rotation shaft through the integrated leaf spring, eliminating the need for additional structural elements
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 provides a stable load spring for smooth rotating operation of the rotation shaft while maintaining light guide performance and preventing deformation, making the device suitable for thin structures.
Implementation Method 1
a braking spring configured to urge the gear in a direction of an axis of rotation of the gear
Implementation Method 2
a gear body, configured to be rotated by a torque transmitted from the step motor
Data Source
AI summary
A meter unit includes a step motor, a gear, a braking spring and a case. The gear has a gear body and a rotation shaft. The braking spring urges the gear in a direction of an axis of rotation of the gear. The case accommodates the step motor, the gear body, a part of the rotation shaft, and the braking spring therein. The braking spring has a shape through which the first part of the rotation shaft passes. A first face of the gear body is formed with a recessed portion which accommodates the braking spring. A first part of the case supports a second face of the gear body. A second part of the case is configured to press the braking spring so that entire part of the braking spring is accommodated in the recessed portion.