Bicycle Speed Sensor Fixed Positioning on Brake Disk
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Solution Overview
Problem
Existing bicycle speed sensors experience inaccuracies due to vibrations causing displacements of sensing components, leading to unreliable speed measurements.
Innovation Solution
A bicycle speed sensor system where the signal transmitter and sensor are fixedly positioned on the brake disk and chain stay, respectively, using a quick-release structure and fixing holes to prevent displacement, with the signal transmitter including a central ring and extending sensing portions to maintain accurate signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the signal transmitter and signal sensor are installed without casing on the bicycle, then the device complexity is reduced and ease of manufacture is improved, but vibration causes displacements of the sensing components leading to measurement precision degradation
Solution Approach 1:
The sensing system is divided into separate functional components: the signal transmitter integrated with the brake disk and the signal sensor mounted on the chain stay. This segmentation allows each component to be independently positioned and secured, reducing vibration-induced displacement while maintaining manufacturing simplicity.
Solution Approach 2:
The signal transmitter is pre-integrated with the brake disk during manufacturing, ensuring precise initial positioning. The brake disk groove is designed in advance to accommodate and secure the transmitter, preventing displacement before the bicycle is even assembled.
2Measurement precision
If the signal transmitter and signal sensor are fixedly disposed at default positions on the brake disk and chain stay, then measurement precision is improved by preventing displacement, but device complexity increases due to additional positioning structures
Solution Approach 1:
The signal transmitter is merged with the brake disk as an integrated component, eliminating the need for separate mounting structures. The brake disk groove serves dual purposes: structural integrity and positioning the transmitter, thereby reducing overall device complexity while ensuring precise positioning.
Solution Approach 2:
The brake disk serves multiple functions: it provides braking surface, structural support, and positioning for the signal transmitter through its integrated groove. This multi-functionality eliminates the need for dedicated mounting structures, reducing device complexity while maintaining measurement precision.
3Measurement precision
If the signal transmitter extends outward from the brake disk, then the sensing capability is improved, but wind resistance increases due to larger exposed surface area
Solution Approach 1:
The signal transmitter sensing portions extend radially outward from the brake disk in a direction perpendicular to the wind flow. This dimensional arrangement allows the sensing surfaces to be oriented optimally for detecting wheel rotation while minimizing their projected area against the wind, thereby reducing wind resistance.
Solution Approach 2:
The brake disk groove is designed with specific local geometric properties that accommodate the signal transmitter's extending sensing portions. The groove provides localized support and positioning only where needed for sensing functionality, while the overall brake disk maintains a streamlined shape to minimize wind resistance.
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 ensures reliable and accurate speed sensing data by preventing sensor displacement and reducing wind resistance through fixed positioning close to the bicycle body.
Implementation Method 1
a signal transmitter configured to transmit a signal, wherein the signal transmitter is fixedly disposed on a side of the brake disk adjacent to the chain stay
Data Source
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AI summary
A bicycle speed sensor is provided on a bicycle (1). The bicycle (1) includes a chain stay (2), a rear wheel (3), a brake disk (4) and a positioning member (5). The rear wheel (3) includes a hub (3a) and the brake disk (4) includes a center hole (4a) disposed for the hub (3a) to pass through. The positioning member (5) passes through the chain stay (2), the center hole (4a) and the hub (3a) so that the rear wheel (3) and the brake disk (4) are positioned on the chain stay (2). The bicycle speed sensor includes a signal transmitter (10) and a signal sensor (20). The signal transmitter (10) is configured to transmit a signal and disposed on the brake disk (4). The signal sensor (20) receives the signal from the signal transmitter (10) and is disposed on the chain stay (2). By fixedly positioning the signal transmitter (10) and the signal sensor (20) at the brake disk and a default position of and the chain stay respectively, displacements of sensor components is prevented to provide reliable sensing data.