Motorcycle Brake Device Lean Angle Control

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Solution Overview

Problem

Existing brake devices for saddle riding vehicles, such as motorcycles, face challenges in maintaining the vehicle's leaned attitude during turns while activating the brakes, leading to difficulties in maneuverability due to the reduction in lean angle when the front wheel brake is activated.

Innovation Solution

A brake device that includes a front wheel brake, a rear wheel brake, a brake operation unit, a lean angle detection sensor, and a control system to adjust the braking force ratio between the front and rear wheels based on the vehicle's lean angle, allowing for reduced front wheel braking force and increased rear wheel braking force when the vehicle is leaned, thereby maintaining the leaned attitude during turns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the front wheel brake is activated hard during a turn with leaned vehicle body, then the braking force increases, but the vehicle body rises and the lean angle reduces making it difficult to turn

Engineering Contradiction:
Improvebraking forceVSAvoidturning ease
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent changes the braking force distribution parameters based on the vehicle's lean angle. When the lean angle is large (vehicle is leaned), the system reduces the front wheel brake force ratio and increases the rear wheel brake force ratio. This dynamic parameter adjustment prevents the vehicle body from rising during turns while maintaining effective braking, thereby resolving the contradiction between braking force and turning ease.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the braking force of the front wheel brake is increased, then the braking performance improves, but the vehicle body attitude changes and maneuverability deteriorates

Engineering Contradiction:
Improvebraking performanceVSAvoidmaneuverability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic braking force distribution system that continuously adjusts the ratio of front and rear wheel braking forces based on real-time lean angle detection. This dynamic adaptation allows the system to maintain optimal braking performance across different vehicle attitudes and turning conditions, resolving the contradiction between reliable braking and adaptable maneuverability.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If a fixed braking force distribution is used, then the device complexity is low, but the adaptability to different riding conditions deteriorates

Engineering Contradiction:
Improvebrake control systemVSAvoidbraking adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent employs a feedback mechanism where a lean angle detection sensor continuously monitors the vehicle's lean angle and provides this information to the control unit. The control unit then adjusts the braking force distribution accordingly. This feedback loop enables the system to adapt to different riding conditions automatically, achieving high braking adaptability without excessive complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical linkage systems with electronic control. Using an ECU to manage braking force distribution based on sensor input simplifies the mechanical structure while dramatically improving adaptability to various riding conditions and vehicle attitudes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2810836B1Brake device and method for a straddle-type vehicle
Publication Date: 2018.08.29 YAMAHA MOTOR CO LTD
  • EP2810836B1 patent drawingFigure 1
  • EP2810836B1 patent drawingFigure 2
  • EP2810836B1 patent drawingFigure 3

AI summary

A structure that allows a vehicle body to be maintained in a leaned state while the vehicle body is turned in the leaned state and brakes are activated is provided. A lean angle detection sensor (54) detects a lean angle of the vehicle body of a motorcycle (1). A storage (551) stores a second relation that represents a ratio of the braking force of the front wheel brake (51) to target braking force for each lean angle and/or a third relation that represents a relation with a ratio of the braking force of the rear wheel brake (52) to the target braking force for each lean angle. The ratio setter (554) determines which second relation to refer to among the second relations stored in the storage (551) based on a detection result input to a detection result input portion (552) and/or determines which third relation to refer to among the third relations stored in the storage (551) based on a detection result input to a detection result input portion (552). The ratio setter (554) sets a ratio of the braking force of the front wheel brake (51) and the braking force of the rear wheel brake (52) based on the second relation and/or the third relation.