Power-Based Self-Shifting Bicycle With CVT Gear Control

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Solution Overview

Problem

Existing bicycle shifting systems require manual gear changes, which are inefficient and tiring for riders, especially when traversing varied terrain, as they demand fluctuating work output rather than a constant power output.

Innovation Solution

A self-shifting bicycle equipped with a graphical control system and a continuously-variable transmission (CVT) that automatically adjusts the gear ratio based on the rider's power output, using a computer and stepper motor to maintain a set preferred power output without manual intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual gear changing is used, then the rider can control the gear ratio, but the shifting process is inefficient and tiring

Engineering Contradiction:

Improveshifting efficiencyVSAvoidrider fatigue

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The system automatically monitors rider power output and adjusts gear ratios without manual intervention. The computer-controlled mechanism detects when shifting is needed and executes the change, allowing the transmission system to serve itself rather than requiring continuous rider attention and action.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical shifting with an automated computer-controlled system. Sensors monitor power output and transmit data to a computer that controls the shifting mechanism, substituting the rider's manual mechanical operation with an automated electromechanical system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the rider manually guesses the right gear combination, then shifting can occur, but concentration is detracted from other important aspects of bicycling

Engineering Contradiction:

Improvebicycling efficiencyVSAvoidrider concentration

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The transmission system monitors its own operating conditions through power output sensors and automatically makes shifting decisions. This self-service capability removes the cognitive burden from the rider, allowing them to focus entirely on riding technique and road awareness rather than gear selection.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system continuously monitors power output and uses this feedback to determine optimal shifting timing. The computer processes real-time data about rider effort and adjusts gear ratios accordingly, creating a closed-loop control system that responds dynamically to changing riding conditions without rider intervention.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If fluctuating work output is required to traverse varied terrain, then the rider can adapt to different slopes, but the rider becomes exhausted on both physical and psychological level

Engineering Contradiction:

Improveterrain adaptationVSAvoidrider exhaustion

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The system dynamically adjusts gear ratios in real-time based on monitored power output and detected terrain changes. This dynamic adaptation allows the transmission to optimize mechanical advantage continuously, maintaining steady power delivery across varying slopes without requiring the rider to physically adapt their effort levels.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The computer system continuously monitors power output and uses this feedback to detect when terrain changes require gear adjustment. By responding to feedback about rider effort and mechanical load, the system maintains optimal operating conditions and prevents the physical and psychological exhaustion associated with manual terrain adaptation.

Inventive Principle:

Principle #23Feedback

4Adaptability or versatility

If more gear ratios are provided (27 speed systems), then the range of available gear combinations increases, but the complexity of choosing the right gear increases

Engineering Contradiction:

Improvegear rangeVSAvoidshifting complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The automated system manages the complexity of 27 gear ratios by making shifting decisions itself based on power output monitoring. The rider benefits from the full range of 27 gears without needing to understand or manually select among them, as the system self-manages the complexity through automated detection and execution of appropriate shifts.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The computer system uses feedback from power output sensors to intelligently select from the 27 available gear ratios. This feedback-driven approach allows the system to navigate the complexity of multiple gears by making data-based decisions about optimal gear selection, removing the cognitive burden from the rider while maintaining access to the full gear range.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10941857B2Self-shifting bicycle that shifts as a function of power output

Publication Date: 2021.03.09 SONENTHAL AVRAHAM

AI summary

A self-shifting bicycle that shifts intelligently as a function of power output. The bicycle uses a computer control system mounted to the handlebar, a power meter attached to the front gearwheel, and an actuator module for adjusting the transmission. The computer control system software changes output gear ratio in accordance with load encountered as the cyclist rides. This allows the rider to set a preferred power output and to maintain that preferred power output very closely.