Parking Brake Clamping Force Adjustment via Induced Voltage
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Solution Overview
Problem
Existing electromechanical parking brakes face challenges in accurately adjusting clamping force due to changes in motor parameters caused by wear, thermal influences, and production variations, which affect the overall resistance and thus the clamping force.
Innovation Solution
The method determines the total resistance in the electromotive braking device by measuring the induced voltage when the circuit is open, allowing for precise calculation of the clamping force, and if necessary, adjusts it by engaging an additional hydraulic braking component to maintain the setpoint force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the clamping force is adjusted using an electromechanical actuator, then the parking brake can be controlled automatically, but the clamping force becomes inaccurate due to changes in motor parameters caused by wear, thermal influences, and production variations
Solution Approach 1:
The system measures the actual clamping force using a force sensor and compares it with the desired setpoint force. Based on this feedback, the control unit adjusts the drive current to the electromechanical actuator, compensating for parameter changes due to wear, thermal influences, and production variations. This closed-loop control ensures accurate clamping force maintenance throughout the braking device's operational life.
Solution Approach 2:
The system dynamically adjusts the drive current parameter based on measured clamping force deviations. By changing the electrical input parameter (current) in response to detected force variations, the system compensates for changes in motor characteristics caused by aging and environmental conditions, thereby maintaining accurate clamping force control.
2Ease of manufacture
If the total resistance is determined using traditional methods, then the calculation is straightforward, but the clamping force determination is inaccurate due to unaccounted temperature and aging effects
Solution Approach 1:
The system continuously monitors the actual clamping force and uses this feedback to determine the effective resistance of the electromechanical actuator. By measuring the relationship between drive current and actual clamping force, the system accurately determines resistance while accounting for temperature and aging effects, combining simplicity with high reliability.
Solution Approach 2:
The system replaces traditional mechanical resistance measurement methods with an electrical measurement approach. By measuring voltage and current in the actuator circuit and calculating resistance electrically, the system achieves both simplicity of implementation and accuracy that accounts for thermal and aging influences on the actuator's electrical characteristics.
3Measurement precision
If additional braking devices are engaged to compensate for parameter changes, then the clamping force accuracy is maintained, but the device complexity increases
Solution Approach 1:
The control unit serves multiple functions: it controls the electromechanical actuator, processes sensor signals, determines resistance, calculates required clamping force, and adjusts drive current. By making the control unit multi-functional, the system maintains clamping force accuracy without adding separate dedicated components for each function, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The system merges the control functions for the electromechanical actuator and the hydraulic brake into a single integrated control unit. By combining these functions, the system achieves accurate clamping force control through coordinated operation of multiple braking devices while avoiding the complexity that would result from separate independent control systems.
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 enables accurate and adaptive adjustment of the clamping force, accounting for changes due to aging and temperature, ensuring reliable vehicle fixation and providing an error signal for driver notification if parameters deteriorate.
Implementation Method 1
the total resistance in the electromotive braking device is determined on the basis of an induced voltage in the circuit of the braking device. Here, the circuit is interrupted so that current no longer flows and, due to the motor still turning, a voltage is induced that can be measured or determined.
Data Source
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AI summary
The invention relates to a method for adjusting the clamping force applied by a parking brake, said force being at least partially applied by an electromotive brake device, comprising an electric brake motor. According to the invention, said method determines the total resistance in the electromotive brake device taking into account an induced voltage when opening the electric circuit and determining the clamping force based on the total resistance.