Disc Brake Parking Release Control via Current Feedback
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Solution Overview
Problem
Existing disc brake apparatuses with parking brake mechanisms face challenges in setting appropriate motor rotation time due to mechanical structural variations and temperature characteristics, leading to insufficient or excessive clearance between the piston and thrust member, resulting in issues like drag and longer parking brake application times.
Innovation Solution
A disc brake apparatus with a caliper, piston thrust mechanism, piston holding mechanism, and control unit that detects brake pad separation from the disc to stop the electric motor after a predetermined electric current value is reached, ensuring an appropriate clearance amount between the piston and thrust member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant time is set as the motor driving time during parking brake release operation, then the control is simple, but the clearance amount between piston and thrust member becomes inappropriate due to mechanical structural variation and temperature characteristics
Solution Approach 1:
The control unit monitors the electric current value of the motor during rotation and detects when the brake pad separates from the disc. This feedback mechanism allows the system to adapt to mechanical structural variations and temperature characteristics, ensuring appropriate clearance amount between the piston and thrust member regardless of constant time settings.
Solution Approach 2:
The system changes the control parameter from fixed time to electric current value monitoring. By detecting the electric current value during motor rotation, the system dynamically adjusts the motor stopping point to achieve the appropriate clearance amount, accounting for variations in mechanical structure and temperature conditions.
2Reliability
If the electric motor rotates excessively during parking brake release operation, then the brake pad separation is ensured, but a too much clearance amount is generated between piston and thrust member leading to longer parking brake application time
Solution Approach 1:
The control unit continuously monitors the electric current value during motor rotation and detects the exact moment when the brake pad separates from the disc. This feedback allows the motor to stop at the precise moment of separation, ensuring reliable brake pad separation while minimizing excessive rotation and clearance generation, thus reducing parking brake application time.
Solution Approach 2:
The motor rotation control transitions from a static fixed-time approach to a dynamic control based on real-time electric current value monitoring. The motor continues rotating only as long as needed to achieve brake pad separation, then stops automatically, optimizing both separation reliability and minimizing unnecessary rotation that would increase application time.
3Loss of time
If the electric motor rotates by an insufficient amount during parking brake release operation, then the control time is reduced, but the piston and thrust member cannot secure sufficient clearance amount resulting in drag phenomenon
Solution Approach 1:
The control unit monitors the electric current value during motor rotation and detects when the brake pad separates from the disc. This feedback ensures the motor rotates for the minimum necessary time to achieve sufficient clearance between the piston and thrust member, preventing drag phenomenon while minimizing control time.
Solution Approach 2:
The system replaces mechanical timing mechanisms with electrical current value monitoring. By detecting changes in electric current during motor rotation, the system precisely determines when brake pad separation occurs, ensuring sufficient clearance is achieved without relying on conservative fixed-time settings that would increase control time.
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 allows for optimal clearance between the piston and thrust member at the end of the parking brake release operation, preventing drag and ensuring responsive parking brake application without relying on fixed time settings, thus addressing mechanical and thermal variations.
Implementation Method 1
The control unit detects that the brake pad is separated from the disc after driving the electric motor
Data Source
AI summary
A disc brake apparatus, in which, at the time of a parking brake release operation, a control unit configured to control driving of an electric motor drives the electric motor so as to cause a piston holding mechanism to stop holding a piston, detects separation of a brake pad from a disk, and then stops driving the electric motor after driving the electric motor by a predetermined amount based on a current value of the electric motor.