Electronic Parking Brake Hydraulic Pressure Control
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Solution Overview
Problem
The electronic parking brake system faces issues with inconsistent clamping force due to varying hydraulic pressure, leading to incomplete disengagement and excessive friction, as the existing control logic fails to accurately manage the hydraulic pressure during engagement and disengagement.
Innovation Solution
The system incorporates a pressure sensor to detect actual hydraulic pressure, a controller to adjust the EPB actuator and ESC actuator, and a memory to store hydraulic pressure values, ensuring that the hydraulic pressure is maintained at a required level during both engagement and disengagement to minimize torque requirements and prevent incomplete disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic pressure is applied to the cylinder to move the piston, then the brake pads press the brake disc to generate clamping force, but the clamping force varies depending on the magnitude of hydraulic pressure causing inconsistent engagement
Solution Approach 1:
The pressure sensor provides real-time feedback on the actual hydraulic pressure in the cylinder to the controller. The controller compares the actual pressure with the required pressure and adjusts the ESC actuator accordingly to maintain consistent clamping force during engagement and disengagement operations.
Solution Approach 2:
The system dynamically adjusts the hydraulic pressure parameter by controlling the ESC actuator to supply or release hydraulic pressure based on the detected actual pressure level, ensuring the pressure remains within the optimal range for reliable engagement and disengagement.
2Force
If excessive hydraulic pressure is applied during engagement, then strong clamping force is generated, but the EPB cannot be released with motor torque alone due to excessive engagement
Solution Approach 1:
The ESC actuator serves as an intermediary device that supplies or releases hydraulic pressure to the cylinder. During disengagement, it reduces the hydraulic pressure to an appropriate level, allowing the motor to easily release the engagement without excessive force requirements.
Solution Approach 2:
The pressure sensor detects the actual hydraulic pressure and provides feedback to the controller, which then controls the ESC actuator to release hydraulic pressure when needed, ensuring the pressure is reduced to a level that allows easy motor-driven disengagement.
3Device complexity
If the control logic does not account for hydraulic pressure variations, then simple control is maintained, but friction occurs after disengagement due to control malfunction
Solution Approach 1:
The pressure sensor provides continuous feedback on hydraulic pressure levels to the controller. The controller uses this information to determine when disengagement is complete and when to stop motor operation, preventing residual friction by ensuring complete separation of brake pads from the brake disc.
Solution Approach 2:
The controller proactively reduces hydraulic pressure through the ESC actuator before initiating motor-driven disengagement, and maintains appropriate pressure levels throughout the process to ensure clean separation and prevent post-disengagement friction.
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 enables more accurate and reliable disengagement of the electronic parking brake by consistently supplying hydraulic pressure, reducing the risk of incomplete disengagement and excessive friction, thereby enhancing system performance and product lifespan.
Implementation Method 1
a pressure sensor configured to detect a hydraulic pressure of the cylinder
Implementation Method 2
an electronic parking brake (EPB) including a piston that moves by a hydraulic pressure to press brake pads onto a brake disc, a cylinder in which the piston is provided movably forward and backward
Implementation Method 3
When the motor rotates a spindle member to move a nut member forward, the nut member pushes a piston inside a caliper, and thus brake pads come into contact with a brake disc and clamping force may be generated
Implementation Method 4
an electronic stability control (ESC) actuator configured to generate and supply a hydraulic pressure to the cylinder
Data Source
AI summary
An electronic parking brake system including: an electronic parking brake (EPB) including a piston that moves by a hydraulic pressure to press brake pads onto a brake disc, a cylinder in which the piston is provided movably forward and backward, and an EPB actuator that moves the piston by a motor to press the brake pads onto the brake disc; a pressure sensor configured to detect a hydraulic pressure of the cylinder; an electronic stability control (ESC) actuator configured to generate and supply a hydraulic pressure to the cylinder; and a controller configured to control the EPB actuator and the ESC actuator, wherein the controller is configured to detect an actual hydraulic pressure of the cylinder through the pressure sensor in an EPB disengagement, and when the detected actual hydraulic pressure is higher than a required hydraulic pressure, control the EPB actuator to start an EPB disengagement control.