Angle Sensor Gear Ratio Optimization for Steering Shaft Measurement
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Solution Overview
Problem
Conventional angle sensors experience measurement errors due to large scale factors when determining the rotation of a steering shaft, leading to inaccuracies in angle measurement.
Innovation Solution
The angle sensor employs an optimized gear ratio of 4:1 between the main and subsidiary gears, reducing measurement errors and enhancing data linearity by utilizing a Hall IC to efficiently detect changes in the magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional gear ratio of 2:1 is used between main and subsidiary gears, then the structure is simple and easy to manufacture, but measurement errors increase due to large scale factors
Solution Approach 1:
The patent changes the gear ratio parameter from the conventional 2:1 to a 4:1 ratio between main and subsidiary gears. This parameter change reduces the scale factor, thereby minimizing measurement errors in rotation amount detection while maintaining manufacturing feasibility
2Measurement precision
If a larger gear ratio is used to reduce measurement errors, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent optimizes the gear ratio to 4:1, which provides the optimal balance between reducing measurement errors and maintaining device simplicity. This parameter optimization achieves high measurement precision without excessive device complexity
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 minimizes measurement errors and increases data nonlinearity, providing precise angle measurements while maintaining high sensitivity to magnetic field changes.
Implementation Method 1
a magnetic device detects magnetic fields and rotating directions of magnets 31 and 32 attached to subsidiary gears 21 and 22
Data Source
AI summary
Disclosed is an angle sensor, which is capable of accurately measuring an angle of a steering shaft by selecting an optimum gear ratio between main and subsidiary gears constituting the angle sensor, measures a rotation amount of a vehicle steering shaft, and includes a ring-shaped main gear (20) rotating along with the steering shaft, a first subsidiary gear (22) rotated by rotation of the main gear and having a magnet (32) coupled to a surface thereof, and a magnetic device detecting a change in magnetic field of the magnet and outputting data on a rotation amount, so that the first subsidiary gear (22) rotates four times while the main gear (20) rotates once, and a value of a scale factor is minimized during a process of acquiring valid data for measuring the angle of the main gear and thereby an error of a measured value is minimized.