Bottom-Neutral Motorcycle Shift Guidance to Reduce Clutch Wear

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Solution Overview

Problem

The bottom-neutral type transmission in straddled vehicles often leads to excessive clutch wear due to unnecessary shift-up operations before starting, caused by rider forgetfulness about previous shift manipulations.

Innovation Solution

A straddled vehicle configuration that includes a bottom-neutral type transmission, a clutch, a gear-shifting manipulation member, a shift direction indicator, and a control device. The control device displays recommendations for shift-up or shift-down operations based on the current transmission state, preventing unnecessary shifts and reducing clutch wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the transmission stage is switched to the second gear before start due to rider forgetfulness, then the gear stage increases, but the clutch wear increases due to prolonged half-clutch state

Engineering Contradiction:
Improveshift operationVSAvoidclutch lifespan
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control device provides visual feedback through the shift direction indicator to show the current transmission state and recommend appropriate shift operations. This feedback mechanism helps riders understand whether they are in neutral or first gear, preventing unnecessary shift-up operations that would cause prolonged clutch wear in the half-clutch state.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The shift direction indicator acts as an intermediary between the transmission system and the rider. It translates the internal transmission state (neutral or first gear) into visible guidance information, helping riders make correct shift operations without directly modifying the transmission mechanism itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the shift direction indicator provides continuous guidance, then clutch wear is suppressed, but the device complexity increases

Engineering Contradiction:
Improveclutch lifespanVSAvoidcontrol system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The shift direction indicator provides guidance only in specific conditions (when the vehicle is stopped and transmission is in neutral or first gear), rather than continuously. This partial action approach reduces unnecessary system complexity while still preventing the harmful scenario of unnecessary shift-up operations before start.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The control device is designed to activate the shift direction indicator only in specific local conditions (stopped state with neutral or first gear), rather than operating uniformly in all conditions. This localized approach minimizes system complexity while effectively addressing the clutch wear problem in the critical pre-start scenario.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4545822A1Straddled vehicle
Publication Date: 2025.04.30 YAMAHA MOTOR CO LTD
  • EP4545822A1 patent drawingFigure 1(a)~1(d)
  • EP4545822A1 patent drawingFigure 2
  • EP4545822A1 patent drawingFigure 3(a)~3(e)

AI summary

A straddled vehicle includes a bottom-neutral type transmission (13), a power source (11), a clutch (12, 52), a gear-shifting manipulation member (13a, 21), a shift direction indicator (15), and a control device (14), the shift direction indicator (15) including both an upward direction indicator (15U) and a downward direction indicator (15D), the shift direction indicator (15) being configured to display a recommended direction for a shift manipulation. When a transmission stage of the bottom-neutral type transmission (13) is the neutral (N), which is the bottommost stage, while traveling of the straddled vehicle is stopped; the control device (14) causes the upward direction indicator (15U) to display recommendation for the shift-up manipulation, and when the transmission stage of the bottom-neutral type transmission (13) is the first gear while traveling of the straddled vehicle is stopped; the control device (14) causes the upward direction indicator (15U) to display non-recommendation for the shift-up manipulation.