Straddle-Type Vehicle Accelerator Grip Transmission Control

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Solution Overview

Problem

Straddle-type vehicles with automatic transmission control struggle to provide appropriate speed reduction desired by riders, as existing methods like braking or engine brake operations do not offer sufficient deceleration, limiting the options for speed reduction during automatic transmission control.

Innovation Solution

A straddle-type vehicle equipped with an actuator that changes the transmission ratio based on the turn of the accelerator grip from a neutral position in the negative direction, allowing for speed reduction by changing the transmission ratio to low-speed, in addition to braking and engine brake operations, thereby increasing the options for speed reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If automatic transmission ratio control is implemented, then ease of operation is improved, but the ability to achieve appropriate speed reduction is worsened

Engineering Contradiction:
Improveease of operationVSAvoidspeed reduction capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The accelerator grip is designed to detect not only the magnitude of opening but also the direction of operation. When the grip is operated in the negative direction (closed direction), the control unit interprets this as a speed reduction request and adjusts the transmission ratio accordingly. This dynamic detection of operation direction enables the automatic transmission to provide appropriate speed reduction while maintaining ease of operation.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If transmission ratio is changed toward low-speed during automatic control, then speed reduction capability is improved, but device complexity is worsened

Engineering Contradiction:
Improvespeed reduction capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The accelerator grip serves multiple functions: it controls engine power output through its opening magnitude and simultaneously controls transmission ratio selection through its operation direction. By making the accelerator grip a multi-functional input device, the system achieves enhanced speed reduction capability without adding separate control mechanisms, thus avoiding increased device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple speed reduction methods are provided, then speed reduction capability is improved, but ease of operation is worsened

Engineering Contradiction:
Improvespeed reduction optionsVSAvoidoperational simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The control unit merges multiple speed reduction methods (braking operation, engine brake, and transmission ratio change) into a unified control system. When the accelerator grip is operated in the negative direction, the control unit automatically selects and executes the appropriate speed reduction method based on current vehicle conditions, eliminating the need for the rider to manually choose between different methods and maintaining operational simplicity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2716533B1Straddle-type vehicle
Publication Date: 2015.04.15 YAMAHA MOTOR CO LTD
  • EP2716533B1 patent drawingFigure 1A~1B
  • EP2716533B1 patent drawingFigure 2
  • EP2716533B1 patent drawingFigure 3A~3B

AI summary

An accelerator grip (24) can turn from a neutral position in a positive direction and a negative direction. A controller (30) controls a transmission (13) so that a transmission ratio of the transmission (13) coincides with a transmission ratio obtained according to an amount of turn of the accelerator grip (24). The controller (30) changes the transmission ratio of the transmission (13) toward a low-speed due to the turn of the accelerator grip (24) from the neutral position in the negative direction. Thereby, a straddle-type vehicle that can obtain appropriate speed reduction desired by a rider may be realized in automatic control of the transmission ratio.