Vehicle Braking Device Mode Switching for Brake Feel
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Solution Overview
Problem
Existing vehicle braking devices lack effective switching between operating modes, leading to a worsening of brake feeling during driver operations, as they rely exclusively on operating force without utilizing the stroke simulator function and fluid-tight sealing of the pistons' chamber.
Innovation Solution
A braking device that switches between two operating modes based on the driver's brake operation, using a control system to select the appropriate mode by judging the operating amount and speed, maintaining drive hydraulic pressure to prevent ineffective operations and maintain normal brake feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the braking device uses hydraulic pressure control exclusively, then the brake operation feels normal, but the drive force becomes insufficient when high braking force is required
Solution Approach 1:
The system dynamically switches between two operating modes based on real-time conditions: hydraulic pressure control mode for normal braking, and mechanical transmission mode when high drive force is needed. This dynamic adaptation allows the system to optimize both brake feeling and drive force output according to the specific operating situation.
Solution Approach 2:
The control portion monitors operating parameters (brake operation amount, increasing speed) and changes the system's operational state by switching between hydraulic control and mechanical transmission modes. This parameter-based switching enables the system to maintain normal brake feeling while providing sufficient drive force when required.
2Force
If the braking device switches between operating modes, then the drive force increases, but the brake feeling deteriorates
Solution Approach 1:
The control portion performs preliminary assessment of the braking situation by monitoring the operating amount and its increasing speed before switching modes. This preliminary action allows the system to anticipate when high drive force will be needed and switch modes proactively, preventing deterioration of brake feeling during the transition.
Solution Approach 2:
The system continuously monitors brake operation parameters and uses this feedback to determine when to switch between operating modes. This feedback mechanism ensures that mode switching occurs only when appropriate, maintaining consistent brake feeling while providing sufficient drive force when needed.
3Reliability
If the hydraulic pressure is maintained during mode switching, then the brake feeling remains consistent, but the response time increases
Solution Approach 1:
The control portion determines the optimal switching timing in advance by monitoring operating parameters, allowing the system to prepare for mode transitions before they are critically needed. This preliminary determination minimizes the actual response time while maintaining consistent brake feeling through proper pressure management.
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 allows for appropriate mode switching, preventing the worsening of brake feeling by ensuring consistent brake operation and generating a high drive force when needed, thus maintaining normal brake performance.
Implementation Method 1
a master cylinder (1) which has a master chamber (1D) that generates a master hydraulic pressure
Implementation Method 2
a wheel cylinder (541-544) which generates a hydraulic pressure at a brake caliper based on the master hydraulic pressure
Data Source
AI summary
The braking device for a vehicle includes an operation judging portion which judges whether or not the operating amount in the increasing stage is equal to or more than a predetermined threshold amount or whether or not an increasing speed of the operating amount in the increasing stage is equal to or more than a predetermined threshold speed and a control portion which selects the first operating mode as the operating mode from a start of the increasing stage until a first timing or a second timing and selects the second operating mode as the operating mode in the increasing stage after the first timing or the second timing and at the same time maintains the drive hydraulic pressure in the increasing stage after the first timing or the second timing.