Gear Sensor Biasing Structure for Backlash-Stable Angle Detection
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Solution Overview
Problem
The accuracy of rotation angle detection in sensor devices is compromised due to the shifting axis of the driven gear within the support hole, leading to variations in detection results caused by clearance and backlash between the driven gear and the main driving gear.
Innovation Solution
The sensor device incorporates a biasing member that decomposes its force into components orthogonal and parallel to the direction reducing backlash, ensuring the driven gear is pressed against the support hole's inner surface, maintaining its position and reducing backlash, while a torsion coil spring with arm portions biases the driven gears towards the main driving gear, and a tubular member prevents direct contact to minimize wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shaft portion is supported inside the support hole with a clearance, then the driven gear can rotate freely, but the axis of the driven gear shifts causing variation in detection accuracy
Solution Approach 1:
A tubular member is introduced as an intermediary between the biasing member and the shaft portion. The biasing member biases the tubular member toward the main driving gear, which in turn biases the driven gear. This intermediary structure prevents direct contact between the biasing member and shaft portion, eliminating wear while maintaining positioning stability and detection accuracy through the clearance support configuration
2Reliability
If the biasing member biases the driven gear toward the main driving gear, then backlash is reduced, but the shaft portion may contact the support hole causing wear
Solution Approach 1:
The tubular member serves as a mediator that transmits the biasing force from the biasing member to the driven gear through contact with the gear portion, not the shaft portion. This allows the driven gear to be pressed against the main driving gear for backlash reduction while the shaft portion remains non-contacting with the support hole, eliminating wear
3Speed
If the driven gear operates within the clearance range during rotation, then the gear can rotate smoothly, but the position of the shaft portion changes causing axis shift
Solution Approach 1:
The support hole is configured with specific local qualities: it has a clearance that allows rotation but is sized to restrict excessive movement. The tubular member is positioned within this clearance zone, allowing smooth rotation while the biasing force maintains the shaft portion in a stable position within the clearance, preventing axis shift
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 stabilizes the driven gear's position within the support hole, reducing backlash and maintaining detection accuracy, and reduces wear by preventing direct contact between the biasing member and the shaft portion, thereby enhancing the reliability of rotation angle measurements.
Implementation Method 1
a biasing member configured to bias the driven gears toward the main driving gear
Implementation Method 2
a torsion coil spring with arm portions biases the driven gears towards the main driving gear
Implementation Method 3
The shaft portion is pressed toward the inner circumferential surface of the support hole... the operation of the driven gear within a range of the clearance is restricted
Data Source
AI summary
A sensor device includes a main driving gear, driven gears, an biasing member configured to bias the driven gears toward the main driving gear, a support member configured to support the biasing member, and a sensor configured to generate an electrical signal based on rotation of the driven gears. In a force applied when the biasing member biases the driven gears, assuming that a direction orthogonal to a tangent line at a point of action of the force is set as a first direction, the first direction is different from a second direction.