Motorcycle Brake Device with Dual Mode Hydraulic Control
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Solution Overview
Problem
Straddled vehicles, such as motorcycles, face challenges in distributing braking forces between the front and rear wheels independently, leading to uncomfortable driving experiences and increased load on the driver, especially when the power is off or during electrical issues, as existing systems do not effectively manage braking forces without electronic control.
Innovation Solution
A brake device with a single operation member that adjusts hydraulic pressures for both wheels, using a storage to correlate operation amounts with target braking forces, ensuring stable deceleration by maintaining consistent braking force distribution between the front and rear wheels, even when the hydraulic pressure control is not operational.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single operation member is used to control both front and rear brakes, then the operation load on the driver is reduced, but the braking force distribution becomes unstable when electronic control is unavailable
Solution Approach 1:
The brake device dynamically switches between two operational modes: electronic controlled brake force distribution mode (when power is available) and mechanical direct transmission mode (when power is unavailable). The hydraulic pressure control device acts as an electronic control actuator that can be activated or deactivated based on power availability, allowing the system to adapt its control strategy to current operational conditions while maintaining stable braking performance in both modes
Solution Approach 2:
The system changes the control parameter transmission method based on power availability. When power is available, the ECU electronically controls the hydraulic pressure control device to distribute brake forces according to ideal braking force distribution characteristics. When power is unavailable, the system switches to mechanical direct transmission where the operation pressure directly controls both brakes without electronic intervention, ensuring continuous reliable operation across different power states
2Reliability
If electronic control is used to distribute braking forces, then ideal braking force distribution is achieved, but the system becomes non-operational when power is off or electrical issues occur
Solution Approach 1:
The brake device is designed with a preliminary mechanical direct transmission path that is always available, independent of the electronic control system. This mechanical path is prepared in advance and can immediately take over when electronic control becomes unavailable, ensuring that the braking function remains operational under all conditions without requiring complex fallback mechanisms
Solution Approach 2:
The brake control system is segmented into two independent subsystems: an electronic control subsystem (ECU and hydraulic pressure control device) that provides ideal braking force distribution when available, and a mechanical direct transmission subsystem that provides reliable basic braking function when electronic control is unavailable. This segmentation allows each subsystem to operate independently based on power availability, enhancing overall system adaptability
3Reliability
If separate brake controls are used for front and rear wheels, then braking force distribution is simple and reliable, but the driver experiences increased operation load
Solution Approach 1:
The brake device merges the control functions for front and rear brakes into a single operation member (brake lever). When the brake lever is operated, it generates operation pressure that is transmitted through a single hydraulic line to both the front wheel brake and rear wheel brake simultaneously. This merging of control functions reduces the number of separate controls the driver must manage, significantly reducing operation load while maintaining reliable braking control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces the load on the driver during braking and enhances comfort by maintaining stable deceleration without sudden changes in braking force, allowing for smooth operation even when the power is off or electrical issues occur.
Implementation Method 1
a hydraulic pressure control device that performs hydraulic pressure control so as to acquire a braking force to be exerted on the front wheel as a first target braking force, and acquire a braking force to be exerted on the rear wheel as a second target braking force
Implementation Method 2
a hydraulic pressure generation device that respectively supplies hydraulic pressures corresponding to an operation amount of the operation member to the first brake and the second brake during a non-operation of the hydraulic pressure control of the hydraulic pressure control device
Data Source
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AI summary
During control ON of a brake control device, an ECU acquires a front wheel target braking force and a rear wheel target braking force from operation amount-front/rear wheel target braking force characteristics stored in a storage based on a master cylinder pressure detected by a master pressure sensor, and controls an oil pressure unit such that oil pressures corresponding to the acquired front wheel target braking force and rear wheel target braking force are respectively supplied to a front wheel brake and a rear wheel brake. During control OFF of the brake control device, oil pressures generated by a tandem master cylinder are directly supplied to the front wheel brake and the rear wheel brake. Hydraulic pressure control is performed such that operation amount-both wheels target braking force characteristics in a control ON state is equal to operation amount-both wheels target braking characteristics during a control OFF state.