Rotation Angle Sensor Dual-Play Shaft Alignment
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Solution Overview
Problem
Existing rotation detection apparatuses face issues with decentering of the input rotary shaft, leading to prying and reduced durability of the magnetic flux generating member, as well as compromised detection accuracy.
Innovation Solution
A rotation angle sensor design incorporating a first shaft member with play in one direction, a second shaft member generating magnetic flux with play in a perpendicular direction, and a rotation guide member to support the second shaft member, ensuring alignment of the magnetic flux generating part with the detection axis, thereby preventing prying and maintaining high detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the input rotary shaft is directly inserted into the magnetic flux generating member to be held therein, then the structure is simple, but decentering occurs causing prying that reduces durability
Solution Approach 1:
The patent divides the shaft support function into two separate shaft members: a first shaft member that holds the input rotary shaft and a second shaft member that generates magnetic flux. This segmentation allows each member to independently accommodate decentering in different directions, preventing prying while maintaining structural simplicity.
2Measurement precision
If the shift between the rotation axis of the magnetic flux generating member and a sensor center is rectified, then detection accuracy is improved, but the magnetic flux generating member may be damaged due to prying
Solution Approach 1:
The patent introduces dynamic adjustment capability through play (clearance) in both X and Y directions between the first and second shaft members. This allows the system to adapt to decentering conditions dynamically, maintaining alignment accuracy while preventing damage from rigid constraint.
3Reliability
If play is provided in both X and Y directions between shaft members, then decentering is accommodated preventing damage, but alignment precision may be reduced
Solution Approach 1:
The patent solves the alignment precision issue by using a rotation guide member that defines a precise rotation center in the Z direction (axis of rotation), while allowing play in the X and Y directions. This dimensional separation enables independent handling of radial play and axial alignment, maintaining precision despite radial decentering accommodation.
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 effectively reduces prying due to decentering, enhancing the durability and detection accuracy of the rotation angle sensor by allowing for relative movement in both X and Y directions while maintaining alignment of the magnetic flux generating part with the detection axis.
Implementation Method 1
a second shaft member that generates magnetic flux and holds the first shaft member with play in a second direction to rotate with the first shaft member
Implementation Method 2
a detection element that is opposed to the second shaft member via the rotation guide member to detect the magnetic flux that changes according to a rotation angle of the second shaft member
Data Source
Figure 1
Figure 2~3
Figure 4(A)~4(B)
AI summary
A rotation angle sensor includes a first shaft member that holds an input rotary shaft with play in a first direction to rotate with the input rotary shaft, the first direction being perpendicular to the input rotary shaft; a second shaft member that generates magnetic flux and holds the first shaft member with play in a second direction to rotate with the first shaft member, the second direction being perpendicular to the input rotary shaft and the first direction; a rotation guide member that rotatably supports the second shaft member and defines a rotation center of the second shaft member; and a detection element that is opposed to the second shaft member via the rotation guide member to detect the magnetic flux that changes according to a rotation angle of the second shaft member.