Gyro Sensor Drive Spring Thin Section Vibration Control
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Solution Overview
Problem
Existing gyro sensors experience unnecessary vibration in the Y-axis direction due to deviations in the cross-sectional shape of the spring structure from a rectangular shape, leading to degraded angular velocity detection characteristics.
Innovation Solution
The physical quantity sensor incorporates a drive spring with thin sections that are thinner than other spring structures, arranged in a specific configuration to reduce the Z-axis-direction vibration component, thereby minimizing unnecessary vibration and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the spring structure has a non-rectangular cross-sectional shape (e.g., parallelogrammatic), then the manufacturing process is simpler and more adaptable to common processing errors, but unnecessary vibration (quadrature) occurs in the Y-axis direction degrading detection precision
Solution Approach 1:
The patent applies local quality by creating a thin section at a specific location (one end) of the spring structure. This localized modification changes the mass distribution and stiffness characteristics only in the critical region, allowing the spring to compensate for shape deviations without requiring the entire spring structure to be perfectly rectangular. The thin section acts as a local counterbalance that reduces quadrature vibration while maintaining manufacturing simplicity.
Solution Approach 2:
The patent changes the physical parameter of the spring structure by introducing a thin section with reduced thickness at one end. This parameter change (local thickness reduction) modifies the vibrational characteristics of the spring, specifically reducing the Y-axis vibration component. By adjusting the thickness parameter locally rather than changing the overall geometry, the patent achieves better vibration control while maintaining ease of manufacture.
2Measurement precision
If laser ablation or material deposition is applied to the spring structure surface to reduce unnecessary vibration, then some reduction in quadrature is achieved, but the reduction amount is insufficient and the process adds complexity
Solution Approach 1:
The patent applies segmentation by dividing the spring structure into two distinct regions: a regular section and a thin section. This segmentation allows the spring to function as multiple independent elements working together - the regular section provides overall support while the thin section specifically addresses vibration control. This structural segmentation achieves better vibration reduction than surface treatments while maintaining manufacturing simplicity through standard etching processes.
3Ease of manufacture
If the spring structure is made with uniform thickness throughout, then the structure is simpler to manufacture, but third-direction vibration component is not reduced effectively
Solution Approach 1:
The patent applies asymmetry by creating an asymmetric thickness distribution in the spring structure - one end has a thin section while the other end maintains regular thickness. This asymmetric design is specifically tailored to counterbalance the effects of non-rectangular cross-sectional shapes that occur during manufacturing. The asymmetric thin section creates a counteracting moment that reduces Y-axis vibration, demonstrating how controlled asymmetry can improve performance while remaining manufacturable.
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 effectively reduces unnecessary vibration, enhancing the angular velocity detection characteristic by minimizing displacement in directions other than the intended X-axis direction, resulting in improved sensor performance.
Implementation Method 1
The spring includes a plurality of spring structures having a longitudinal direction extending along a second direction perpendicular to the first direction and folding sections that each connect same-one-side ends of adjacent two spring structures of the plurality of spring structures. At least any of the plurality of spring structures includes a thin section thinner than other spring structures along a third direction perpendicular to the first and second directions.
Implementation Method 2
When angular velocity around a Z axis (axis perpendicular to both X axis and Y axis) acts on the thus configured gyro sensor in a state in which the frame vibrates along with the proof mass in the X-axis direction (the state is hereinafter referred to as a 'drive vibration mode'), a Coriolis force displaces the proof mass in the Y-axis direction
Implementation Method 3
the capacitance between the proof mass and the sense electrode changes. The angular velocity can therefore be detected based on the change in the capacitance.
Data Source
AI summary
A physical quantity sensor includes a driven section and a drive spring that supports the driven section so that the driven section is displaceable in a first direction. The drive spring has a serpentine shape and includes a plurality of spring structures extending in a second direction that intersects a first direction. At least one of the spring structures has a thin section that is thinner in a third direction that intersects the first and second directions than the other portions of the drive spring.