Automatic Parking Brake Clamping Force Maintenance via Pressure Gradient
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Solution Overview
Problem
Conventional automatic parking brake systems experience a loss of clamping force due to temperature changes in the brake disk, leading to inefficient reapplication and increased loading on components, particularly in stiff brake systems, due to inaccurate temperature models and thermal relaxation.
Innovation Solution
The method involves determining a pressure loss gradient in the braking circuit to assess the clamping force loss and adjust the automatic parking brake application accordingly, minimizing unnecessary reapplications and reducing component loading by using hydraulic pressure buildup and angle of inclination considerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the automatic parking brake is further applied multiple occasions to compensate for clamping force loss, then the reliability of clamping force maintenance is improved, but the loading on components (electric brake motor and gear mechanism) increases
Solution Approach 1:
The system uses pressure sensors to continuously monitor the actual clamping force and feeds this information back to the control device. The control device compares the actual clamping force with the target clamping force and adjusts the brake application accordingly, enabling precise compensation without excessive reapplication.
Solution Approach 2:
The patent replaces the conventional temperature-based open-loop control with a pressure-based closed-loop control system. By using pressure sensors to directly measure clamping force and hydraulic pressure to compensate, the system eliminates the need for multiple mechanical reapplications of the brake, reducing component loading while maintaining reliability.
2Device complexity
If the temperature-based model is used to determine brake disk temperature, then the system complexity is reduced, but the measurement precision of temperature is insufficient leading to inaccurate clamping force compensation
Solution Approach 1:
The patent replaces the temperature-based estimation model with a direct pressure measurement system. Instead of inferring clamping force from temperature models, the system uses pressure sensors to directly measure the actual clamping force and hydraulic pressure, providing precise feedback without complex thermal modeling.
Solution Approach 2:
The system introduces pressure sensors as intermediary measurement devices that directly measure the physical quantity of interest (clamping force and hydraulic pressure) rather than using temperature as an indirect proxy. This intermediary measurement approach provides accurate real-time data for control decisions.
3Reliability
If the automatic parking brake is further applied without considering the necessity, then the reliability is maintained, but the loss of time and increased energy consumption occur
Solution Approach 1:
The control device receives real-time feedback from pressure sensors about the actual clamping force and determines whether further application is necessary based on actual measured values rather than predetermined time intervals or temperature estimates, optimizing reapplication timing.
Solution Approach 2:
The system autonomously monitors its own clamping force status through pressure sensors and self-regulates the brake application based on actual needs, eliminating unnecessary reapplications and optimizing the timing of required reapplications without external intervention.
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 approach ensures reliable clamping force maintenance with reduced component loading and optimized operation, even in stiff brake systems, by precisely determining and compensating for clamping force losses through pressure gradient analysis and angle-dependent adjustments.
Implementation Method 1
the brake piston can be influenced by means of a hydraulic brake fluid which is achieved by means of the regular vehicle brake (service brake)
Implementation Method 2
the brake disk and the brake pads to heat up and expand
Implementation Method 3
During the subsequent cooling process and in the case of simultaneously locked parking brakes, the components 'shrink' causing a part of the clamping force to be lost
Data Source
AI summary
A method for providing a clamping force that is generated with an automatic parking brake for a vehicle using a brake motor and a brake piston that acts upon a brake disk, includes building up a hydraulic pressure in a braking circuit of the vehicle after the automatic parking brake is applied. The method further includes determining a pressure loss gradient in the braking circuit of the vehicle. The method further includes performing or not performing a further application of the automatic parking brake based in part upon the determined pressure loss gradient.