Electronic Brake Backup Hydraulics for Actuator Failure
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Solution Overview
Problem
The electronic brake system faces instability in generating the required braking pressure when a technical problem occurs in an electric component, potentially compromising passenger safety.
Innovation Solution
The system incorporates a hydraulic braking device that generates hydraulic pressure when the actuator is inoperable, allowing the brake to be applied directly through pedal force, and includes a diagnostic mechanism to quickly identify failures and switch to abnormal operation mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an electro-mechanical braking device is used to enable complex and various braking operations, then braking functionality is improved, but reliability deteriorates when electric components fail
Solution Approach 1:
The patent incorporates a hydraulic braking device as a backup system that is activated when the electro-mechanical actuator fails. This backup mechanism is prepared in advance to cushion against the reliability risks of electric component failures, ensuring continuous braking capability through direct hydraulic pressure transmission from the master cylinder to the wheel cylinder.
Solution Approach 2:
The system changes the operating parameter from electrical signal-based braking control to direct hydraulic pressure-based braking control when failure is detected. This parameter change allows the system to transition from electro-mechanical operation to pure hydraulic operation, maintaining braking functionality despite the failure of electric components.
2Reliability
If a hydraulic braking device is added for emergency braking, then reliability is improved, but device complexity increases
Solution Approach 1:
The master cylinder is designed to serve dual functions: normally it works with the electro-mechanical actuator for regular braking operations, but it can directly supply hydraulic pressure to the wheel cylinder when failure occurs. This multi-functionality reduces the need for completely separate systems, thereby limiting the increase in device complexity while maintaining reliability improvements.
Solution Approach 2:
The control unit acts as an intermediary that monitors the status of electric components and automatically switches between the electro-mechanical braking mode and the direct hydraulic braking mode. This intermediary component coordinates the transition between different braking mechanisms, managing the complexity of having multiple braking systems through centralized control.
3Speed
If direct hydraulic pressure transmission is implemented for emergency braking, then response speed is improved, but ease of operation deteriorates due to manual pedal linkage requirements
Solution Approach 1:
The system uses the driver's own brake pedal operation to generate the hydraulic pressure needed for emergency braking. When failure is detected, the control unit simply opens the cut valve to allow direct hydraulic pressure transmission, and the driver's natural pedal pressing action automatically provides the required braking force without needing additional manual linkage mechanisms.
Solution Approach 2:
The patent extracts the essential function of direct hydraulic pressure transmission from the complex electro-mechanical system and isolates it as a separate failure-mode pathway. By removing the electro-mechanical components from this emergency pathway and using only the purely mechanical hydraulic connection between the master cylinder and wheel cylinder, the system achieves fast response while keeping the emergency pathway mechanically simple.
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
This solution ensures stable braking pressure can be generated even with electric component failures, enhancing passenger safety by allowing direct hydraulic pressure application and rapid failure diagnosis.
Implementation Method 1
a pedal simulator disposed inside the master chamber and providing a pedal feeling through an elastic restoration force generated during compression
Implementation Method 2
a hydraulic braking device providing braking force by a hydraulic pressure to at least one wheel cylinder of the plurality of wheels when the actuator is inoperable
Data Source
AI summary
An electronic brake system includes: a plurality of actuators provided in a plurality of wheels, respectively and providing power for braking; and a hydraulic braking device providing braking force by a hydraulic pressure to at least one wheel cylinder of the plurality of wheels when the actuator is inoperable, the hydraulic braking device includes a reservoir storing a pressing medium, a master cylinder including a master piston connected to a brake pedal, a master chamber of which a volume is varied by displacement of the master piston, and a pedal simulator disposed inside the master chamber and providing a pedal feeling through an elastic restoration force generated during compression, a connection path connecting the master chamber and the wheel cylinder, and a cut valve provided in the connection path, and controlling a flow of the pressing medium between the master cylinder and the wheel cylinder.