Electric Parking Brake Controller Smooth Release Control
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Solution Overview
Problem
Existing brake apparatuses with electric parking brake functions experience discomfort and unsmooth brake release operations, particularly on inclined roads, due to abrupt reduction in piston thrust during brake release.
Innovation Solution
A brake apparatus with a controller that performs current maintenance control and switching control, continuously applying electric current to the motor and successively switching between larger and smaller current levels to gradually reduce braking force, ensuring smooth brake release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the electric motor operates at a lower duty ratio to gradually decrease piston thrust reduction rate on inclined roads, then the braking force reduction becomes smoother, but the brake release operation may not be smooth
Solution Approach 1:
The controller performs switching control that periodically switches between applying electric current and not applying electric current to the electric motor during brake release. This periodic action allows the piston thrust to be gradually reduced in a controlled manner, achieving smooth brake release operation while minimizing discomfort to the driver.
Solution Approach 2:
The system dynamically adjusts the duty ratio of electric current application based on vehicle conditions (such as slope detection). By making the duty ratio variable rather than fixed, the system can optimize the brake release characteristics for different operating conditions, ensuring smooth operation while reducing discomfort.
2Productivity
If the piston thrust is rapidly reduced during brake release, then the brake release operation is quick, but discomfort is felt due to abrupt thrust reduction
Solution Approach 1:
Instead of rapidly reducing piston thrust in a single action, the controller uses periodic switching control to gradually reduce thrust over multiple cycles. This approach maintains relatively quick overall release time while distributing the thrust reduction across periodic intervals, preventing abrupt changes that cause discomfort.
Solution Approach 2:
The controller changes the duty ratio parameter of electric current application during brake release. By dynamically adjusting this parameter, the system controls the rate of piston thrust reduction to balance between release speed and comfort, avoiding both too-rapid and too-slow release scenarios.
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 reduces discomfort and achieves smooth brake release operations by gradually reducing piston thrust, enhancing the driving experience by minimizing jerks and resistance during vehicle movement.
Implementation Method 1
an electric motor configured to operate a thrust retaining mechanism to thrust the piston and maintain braking force exerted by the thrust piston, in response to electric current applied to the electric motor
Data Source
AI summary
A brake apparatus comprising: a caliper having a piston configured to move a brake pad to be pressed on a disc rotor rotating with a wheel; a thrust retaining mechanism located in the caliper to thrust the piston and maintain braking force exerted by the thrust piston; an electric motor mounted on the caliper to operate the thrust retaining mechanism; and a controller configured to apply electric current to the electric motor in response to an application command or a release command, thereby perform control according to the commands, wherein the controller, upon receiving a release command, configured to operate the electric motor to reduce braking force exerted by the piston by performing current maintenance control which continuously applies electric current to the electric motor and switching control which successively switches between a larger and a smaller amount of electric current applied to the electric motor.