Brake Mode Switching with Hydraulic Backup for EMB Failure
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Solution Overview
Problem
The existing electro-mechanical braking systems lack sufficient security and reliability, particularly in complete failure conditions, as they do not have a mechanical failure protection device, and existing hybrid systems are complex and costly with limited integration of electro-mechanical braking advantages.
Innovation Solution
A braking system that switches between electro-mechanical and hydraulic modes based on a reversing assembly controlled by an electronic control unit, allowing the electro-mechanical system to provide brake force in normal and non-complete failure conditions and relying on the hydraulic system in complete failure conditions, with a pedal feel simulator for feedback and a two-position three-way reversing valve for fluid direction control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an electro-mechanical braking system (EMB) is used to replace hydraulic systems, then response speed is improved and braking distance is shortened, but system security and reliability deteriorate due to lack of mechanical failure protection
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a hydraulic backup system that activates automatically when the electro-mechanical braking system fails. The hydraulic assembly includes a master cylinder, brake fluid, and wheel cylinders that remain in standby mode during normal EMB operation but provide immediate mechanical failure protection when needed, thus cushioning against the reliability risks of pure EMB systems.
Solution Approach 2:
The patent applies local quality by providing different braking mechanisms for different wheels based on system status. The front wheels are equipped with both EMB actuators and hydraulic wheel cylinders, while rear wheels use EMB actuators. The system dynamically switches between electro-mechanical and hydraulic braking modes, creating localized quality differences in the braking system's operational characteristics across different wheels and operating conditions.
2Reliability
If a hybrid braking system with both hydraulic and electro-mechanical components is used to improve reliability, then system security is improved, but device complexity increases and costs rise
Solution Approach 1:
The patent applies universality by designing the hydraulic assembly to serve multiple functions: it provides mechanical failure protection during normal operation, serves as the primary braking system when EMB fails completely, and enables pedal feel simulation. The same hydraulic components (master cylinder, brake fluid, wheel cylinders) fulfill multiple roles, reducing the need for separate dedicated backup systems and thereby limiting complexity growth.
Solution Approach 2:
The patent applies taking out by extracting only the essential hydraulic components needed for failure protection rather than implementing a complete dual hydraulic system. The system removes unnecessary hydraulic complexity by using a simplified arrangement where the hydraulic assembly is integrated into the existing EMB structure, keeping only the master cylinder, brake fluid reservoir, and wheel cylinders necessary for safety backup and pedal feel simulation.
3Reliability
If the front wheels retain hydraulic brake in a hybrid system, then failure protection is provided, but the system remains complex and costly with limited play to EMB advantages
Solution Approach 1:
The patent applies dynamics by making the braking system's operational mode dynamic rather than static. The reversing assembly (three-way valve) dynamically switches the hydraulic fluid flow direction based on system status: connecting hydraulic wheel cylinders to EMB actuators during normal operation for pedal feel simulation, and connecting them to the master cylinder during failure conditions for mechanical braking. This dynamic switching allows the system to adapt its complexity level to actual operational needs.
Solution Approach 2:
The patent applies intermediary by introducing a reversing assembly (three-way valve) that mediates between the hydraulic assembly and the braking system. This intermediary component directs hydraulic fluid flow to different destinations based on system status, enabling the hydraulic system to serve as both a pedal feel simulator during normal operation and a failure protection mechanism during emergencies, without requiring separate dedicated systems for each function.
4Adaptability or versatility
If electro-mechanical braking is used in all wheels, then independent four-wheel control is achieved, but system complexity and cost increase
Solution Approach 1:
The patent applies partial action by implementing electro-mechanical braking actuators on only two wheels (front or rear) rather than all four wheels. The EMB provides independent control capability on the equipped wheels, while the hydraulic system provides backup and pedal feel simulation. This partial implementation achieves the versatility benefit of independent wheel control where needed while avoiding the full complexity and cost of equipping all four wheels with EMB actuators.
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 full utilization of electro-mechanical braking advantages in normal conditions, provides independent control of four wheels, and ensures safety through hydraulic intervention in complete failure conditions, enhancing system security and reliability.
Implementation Method 1
a brake fluid output end of the hydraulic assembly is connected to the front wheel assembly through the reversing assembly; the input push rod generates displacement under action of the pedal assembly, so that a brake fluid in the hydraulic assembly flows into the front wheel assembly
Implementation Method 2
the brake fluid output end of the hydraulic assembly is connected to the pedal feel simulator through the reversing assembly; the pedal feel simulator is configured to generate feedback force of the pedal assembly
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A braking system includes a pedal assembly (1), a hydraulic assembly (2), a reversing assembly (3), a driving wheel assembly, a pedal feel simulator (6), and a first electronic control unit (7), where the first electronic control unit (7) is electrically connected to the reversing assembly (3), and may control the reversing assembly (3) to switch a working location, and the reversing assembly (3) includes at least two working locations. When the reversing assembly is at a first working location, a brake fluid output port of the hydraulic assembly (2) is connected to the driving wheel assembly through the reversing assembly (3). When the reversing assembly is at a second working location, the first electronic control unit (7) is electrically connected to the driving wheel assembly, and controls the driving wheel assembly to provide brake force. In the system, when a vehicle is in a normal working condition or a non-complete failure working condition, brake force is provided entirely by an electro-mechanical braking system, without depending on a hydraulic system. When the vehicle is in a complete failure working condition, brake force can be provided by the hydraulic system in a manner that a driver steps on a brake pedal.