E-Bike Gear Step Estimation Using Transmission Gear Ratio
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Solution Overview
Problem
Existing electric assist bicycles require users to visually confirm the gear step, which is inefficient and lacks visibility.
Innovation Solution
A method and device for estimating the gear step by comparing the acquired gear ratio with reference values, allowing for accurate estimation of the selected gear step using a processor and sensors to determine the gear ratio and match it with predefined values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If visual confirmation of gear step is required, then user can directly see the selected gear, but user experience is degraded and operation becomes cumbersome
Solution Approach 1:
The patent replaces the mechanical visual confirmation system with an electronic estimation system. The control device estimates the gear step by calculating the gear ratio from detected vehicle speed and engine speed, substituting the need for visual inspection of physical gear indicators with automated electronic computation and display.
Solution Approach 2:
The system implements feedback by continuously monitoring vehicle speed and engine speed, estimating the current gear step, and displaying the estimated gear step to the user. This closed-loop feedback mechanism provides real-time gear information without requiring user action to visually confirm the gear position.
2Loss of information
If gear step is displayed visually, then information is provided to user, but visibility and readability are insufficient
Solution Approach 1:
The patent replaces inadequate mechanical visual indicators with an electronic display system that presents gear step information in a more visible and readable format. The control device processes sensor data and outputs gear step information through electronic displays that can be optimized for visibility under various lighting conditions.
3Measurement precision
If traditional gear indication method is used, then device structure is simple, but gear step estimation accuracy is insufficient
Solution Approach 1:
The patent replaces simple mechanical gear indicators with an electronic estimation system that calculates gear step from vehicle speed and engine speed. This substitution increases measurement precision by using sensor data and computational algorithms, while the added complexity is offset by the elimination of mechanical gear indication components.
Solution Approach 2:
The control device performs multiple functions: it controls the switching transmission device, detects vehicle speed and engine speed, estimates the gear step, and displays the estimated gear step. This multi-functionality consolidates what would otherwise require separate components into a single integrated control system, managing the complexity through functional integration.
Data Source
AI summary
A gear step estimation method is of estimating a gear step of a transmission device of an electric assist bicycle including a motor and the transmission device which is provided in a power transmission path between the motor and a rear wheel and is capable of switching the gear step among n gear steps. The gear step estimation method includes a step of acquiring, at a first time, a gear ratio that is a gear ratio of a transmission section that is the entire or partial power transmission path including the transmission device, a step of comparing the acquired gear ratio with n preset gear ratios set within a range of possible gear ratios taken by the n gear steps, and a step of estimating the gear step of the transmission device as an m-step in a case where the detected gear ratio matches an m-th preset gear ratios.