Electric Bicycle Derailleur Encoder Integration for Precise Shift Sensing
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Solution Overview
Problem
Existing bicycle derailleurs face challenges in achieving accurate and reliable transduction due to the need for precise assembly of encoder components with the geared motor, which complicates production and maintenance.
Innovation Solution
The geared motor is integrated as a self-contained module with a magnetic encoder, where the magnet is coaxial with the output shaft, simplifying assembly and enhancing detection accuracy by integrating the encoder directly on the output shaft, and the magnetic sensor is coaxial with the output shaft, and the magnetic sensor is positioned to maximize signal detection while minimizing encumbrance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic rotary encoder with a permanent magnet on the drive shaft is used, then the measurement precision of rotation angle is improved, but the device complexity increases due to the need for auxiliary components and precise assembly
Solution Approach 1:
The invention extracts the encoder from being a separate auxiliary component and integrates it directly into the geared motor assembly. The permanent magnet is mounted on the output shaft of the geared motor, and the magnetic sensor is built into the geared motor housing, eliminating the need for external encoder components and reducing assembly complexity while maintaining measurement precision
Solution Approach 2:
The encoder components (permanent magnet and magnetic sensor) are merged with the geared motor into a single integrated assembly. The magnet is attached to the output shaft and the sensor is positioned within the motor housing, creating a unified structure that simplifies assembly and reduces the number of separate parts while preserving accurate rotation angle detection
2Measurement precision
If the encoder is associated with the drive shaft or intermediate shaft, then the measurement precision is improved, but the ease of manufacture deteriorates due to complex assembly requirements
Solution Approach 1:
The encoder components are pre-integrated into the geared motor assembly during manufacturing. The permanent magnet is attached to the output shaft and the magnetic sensor is positioned in the motor housing before the complete assembly is installed in the derailleur, simplifying the final installation process while ensuring precise alignment for accurate measurement
Solution Approach 2:
The geared motor assembly serves dual functions: it provides mechanical power transmission through the gear train and simultaneously performs rotation angle detection through the integrated encoder. This self-service approach eliminates the need for separate encoder installation and alignment procedures, improving ease of manufacture while maintaining measurement precision
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 integration improves the reliability and accuracy of the mutual arrangement between the magnet and sensor, enhancing the detection precision and reducing the complexity of the system, thereby improving the detection precision and reducing the assembly time.
Implementation Method 1
a transducer of a quantity related to the mutual motion of the plurality of mutually movable components, of the magnetic rotary encoder type, comprising a permanent magnet and a magnetic sensor responding to the changes in the magnetic field of the magnet
Data Source
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AI summary
A bicycle electric/electronic derailleur comprising a plurality of mutually movable components, and a geared motor (10) for controlling the mutual motion of the plurality of mutually movable components, the geared motor (10) comprising an electric motor (30) having a drive shaft (31), an output shaft (32) and a speed reducer (33) including at least one gear between said drive shaft (31) and said output shaft (32), the output shaft (32) defining at least in part one of said articulation axes, extended between a first and a second of the mutually movable components, the electric motor (31) being rigidly connected to the first of the mutually movable components, and the second of the mutually movable components integrally rotating with the output shaft (32), the derailleur (1) comprising a transducer (200) of a quantity related to the mutual motion of the mutually movable components, of the magnetic rotary encoder type, comprising a permanent magnet (201) and a sensor (202) responding to the changes in the magnetic field of the magnet (201), wherein the magnet (201) is a disc or cylindrical or annular magnet having diametral magnetization, wherein the magnet (201) is coaxial with and integrally rotates with the output shaft (32).