EPB Piston Impact Reduction via Hydraulic Pressure Control
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Solution Overview
Problem
The existing vehicle brake control systems face issues where the piston urged by the service brake collides with the driving shaft with a great impact when the hydraulic brake pressure is released, leading to a large load on the driving shaft, necessitating increased size of the EPB mechanism to withstand this impact.
Innovation Solution
A vehicle brake control device that includes an electronic parking brake, a service brake, and an electronic controller, which performs pressure-decreasing limit control to synchronize the hydraulic brake pressure decrease with the contact of the moving member, preventing a great impact by limiting the pressure decrease until contact is reached, and adjusting the pressure-decreasing rate to ensure the impact force does not exceed a predetermined threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the service brake releases hydraulic brake pressure to move the piston back, then the piston returns to its initial position, but the piston collides with the driving shaft with great impact, applying a large load to the driving shaft
Solution Approach 1:
The patent applies beforehand cushioning by controlling the hydraulic brake pressure to decrease gradually before the piston contacts the driving shaft. The electronic controller monitors the piston position and regulates the pressure release rate, ensuring that the piston moves back smoothly without colliding with the driving shaft. This prevents impact forces and eliminates the need for oversized EPB components to withstand such impacts.
2Strength
If the EPB mechanism is designed to withstand the impact force, then the driving shaft and related components can endure the collision, but the size of the EPB mechanism must be increased
Solution Approach 1:
The patent eliminates the need for oversized EPB components by implementing beforehand cushioning through controlled pressure release. The electronic controller regulates the hydraulic brake pressure to decrease at a controlled rate, ensuring the piston returns smoothly without generating impact forces. This allows the EPB mechanism to be designed with smaller, more compact components while maintaining sufficient strength for normal operation.
3Speed
If the hydraulic brake pressure is released rapidly, then the piston returns to initial position quickly, but the piston collides with the driving shaft, requiring larger EPB components
Solution Approach 1:
The patent resolves the contradiction between fast piston return and impact prevention by implementing beforehand cushioning through electronic pressure control. The electronic controller monitors piston position and regulates the hydraulic brake pressure release rate, allowing the piston to move back quickly yet smoothly without colliding with the driving shaft. This eliminates impact forces while maintaining high return speed, enabling compact EPB design.
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 effectively prevents the piston from colliding with the driving shaft with a great impact, reducing the load on the moving member and allowing for a more compact EPB mechanism, thereby maintaining braking performance without increasing the size of the EPB components.
Implementation Method 1
an electronic parking brake mechanism configured to perform a locking operation of moving a moving member in a first direction in which the first frictional member approaches the second frictional member by forwardly rotationally driving an electric motor to move a pressing member and pressing the first frictional member against the second frictional member by the pressing member
Implementation Method 2
a hydraulic brake pressure generator configured to generate a hydraulic brake pressure, a wheel cylinder that is connected to the hydraulic brake pressure generator, moves the first frictional member in the first direction and presses the second frictional member by the pressing member when the hydraulic brake pressure increases
Implementation Method 3
moves the first frictional member in the second direction in which the first frictional member is separated from the second frictional member by the pressing member when the hydraulic brake pressure decreases
Implementation Method 4
the electronic parking brake performs a pressure-decreasing limit control of limiting the decrease in the hydraulic brake pressure by the hydraulic brake pressure adjusting unit if the contact state is not reached during the locking operation
Data Source
AI summary
When an EPB performs a locking operation of operating a parking brake, a pressure-decreasing limit control is performed until a driving shaft contacts a piston. Accordingly, even when the time of decreasing the W/C pressure by a service brake is equal to the time of brining the driving shaft having moved by the motor driving of the EPB into contact with the piston are equal to each other, it is possible to prevent the piston, which has been urged to the driving shaft with the decreasing of the W/C pressure, from colliding with the driving shaft with a great impact, thereby preventing a large load from being applied to the driving shaft.