Bicycle Rear Suspension Linkage Sensing for Accurate Sag Measurement
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Solution Overview
Problem
Existing technologies face challenges in accurately measuring the path of the rear axle in bicycle suspension systems due to its non-linear travel, leading to errors in suspension adjustment and sag optimization.
Innovation Solution
A rear suspension device for bicycles that includes a first pivot, a second pivot, a third pivot, a first axial compression shock absorber, a linkage unit, a first sensor unit with Hall-effect sensors, and a magnet, allowing for precise measurement of the rear axle's path and adjustment of the shock absorber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electronic means are used to measure suspension sag, then measurement capability is provided, but measurement precision deteriorates due to the non-linear path of the rear axle
Solution Approach 1:
The patent replaces direct mechanical measurement of the rear axle's non-linear path with a magnetic field-based sensing system. Hall-effect sensors detect the position of a magnet attached to the linkage unit, converting complex mechanical motion into electrical signals that can be processed to determine sag accurately despite the non-linear trajectory.
Solution Approach 2:
The patent introduces a magnet as an intermediary carrier attached to the linkage unit, which indirectly indicates the position of the rear axle. The Hall-effect sensors detect the magnet's position, serving as an intermediary measurement point that can be reliably tracked even when the rear axle follows a complex non-linear path.
2Measurement precision
If the rear axle path is measured directly, then position information is obtained, but measurement accuracy deteriorates due to the complex non-linear trajectory
Solution Approach 1:
The patent substitutes direct mechanical path tracking with a magnetic field-based position detection system. The Hall-effect sensors measure the magnet's position in three-dimensional space, and through mathematical transformation, the system calculates the corresponding rear axle position, avoiding the complexity of directly measuring the non-linear path.
Solution Approach 2:
The patent measures the magnet's position in three-dimensional space (x, y, z coordinates) rather than attempting to directly measure the one-dimensional path of the rear axle. This dimensional transformation allows for more accurate position detection by capturing the full spatial trajectory and then converting it to the relevant linear displacement information.
3Reliability
If suspension sag is not accurately adjusted, then shock absorption performance deteriorates, but achieving accurate adjustment is difficult due to measurement errors
Solution Approach 1:
The patent implements a feedback mechanism where the Hall-effect sensors continuously monitor the position of the magnet on the linkage unit, and the control system uses this information to determine the actual sag and provide feedback for adjustment. This closed-loop approach ensures accurate sag adjustment by comparing measured values with target values and making corrective adjustments.
Solution Approach 2:
The patent replaces imprecise mechanical sag measurement methods with electronic Hall-effect sensing, which provides higher resolution and more reliable measurements. This substitution enables precise digital measurement of the linkage unit's position, which is then converted to accurate sag values for proper suspension adjustment.
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
Enables accurate classification of the shock absorber's adjustment status, ensuring correct suspension settings, improved shock absorption, and enhanced traction by accurately measuring the rear axle's travel and adjusting the shock absorber accordingly.
Implementation Method 1
said first sensor unit is located on a surface of said linkage unit and comprises at least one Hall-effect sensor located in a plane perpendicular to the third axis of rotation
Implementation Method 2
a first axial compression shock absorber (7)
Data Source
AI summary
Rear suspension device for a bicycle with three pivots, each with an axis of rotation an axial compression shock absorber, a linkage unit, a sensor unit and a magnet. The axes of rotation are parallel to each other and the axial compression shock absorber has a first end attached to the first pivot and a second end attached to the second pivot. The linkage unit is attached to the second pivot and the third pivot and rotates about the second and third axis of rotation. The sensor unit is on a surface of the linkage unit and comprises a Hall-effect sensor located in a plane perpendicular to the third axis of rotation and located at a distance d1 from the third axis of rotation. The first magnet is: a cylindrical or cylindrical shell magnet having an axis of rotational symmetry which is perpendicular to the parallel faces thereof; or a prism-shaped magnet comprising two polygonal parallel faces and an axis of rotational symmetry which is perpendicular to said parallel faces. The direction of the magnetic moment of the first magnet is perpendicular to said axis of rotational symmetry, and the first magnet is attached to the third pivot. The third axis of rotation and the axis of rotational symmetry of said first magnet are aligned. A distance d2 between said sensor unit and said magnet, and d1 is between 0.1 mm and 50 mm and d2 is between 0.01 mm and 50 mm.