Electric Brake Parking Lock Prevents Unintentional Release
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Solution Overview
Problem
Existing electric brake systems with parking functions can unintentionally release the parking brake when the brake pedal is operated, posing safety risks, especially on slopes or due to creep torque in vehicles with torque converters.
Innovation Solution
An electric brake system with a brake controller that prohibits the electric motor from actuating when the vehicle is stopped and the parking brake operation is complete, using a locking actuator and sensors to maintain engagement of the locking pin with the intermediate gear through frictional resistance, ensuring continuous braking force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric motor is actuated when the brake pedal is operated, then the braking force is applied to the wheel, but the locking pin may disengage from the engaging hole causing unintentional release of the parking brake
Solution Approach 1:
The system dynamically adjusts the actuation state of the electric motor based on the vehicle state and parking brake status. When the vehicle is stopped and parking brake is applied, the motor actuation is prohibited even if the brake pedal is operated. This dynamic control prevents unintentional release of the parking brake while maintaining normal brake operation flexibility when the vehicle is moving or parking brake is not applied.
Solution Approach 2:
The brake controller continuously monitors the vehicle state (stopped or moving) and the parking brake application status, and uses this feedback information to determine whether to permit or prohibit motor actuation. This feedback mechanism ensures that the motor is prohibited from actuating in the specific condition where it could cause parking brake release, while allowing normal operation in other conditions.
2Reliability
If the locking pin is engaged in the engaging hole to prevent rotation of the intermediate gear, then the parking brake is applied continuously, but the frictional resistance may disappear when torque exceeds the reaction force torque
Solution Approach 1:
The system applies preliminary anti-action by prohibiting motor actuation before the torque can exceed the reaction force torque and cause the locking pin to disengage. By preventing the motor from actuating when the vehicle is stopped and parking brake is applied, the system eliminates the risk of torque exceeding the holding capacity of the frictional resistance between the locking pin and engaging hole.
Solution Approach 2:
The control system provides beforehand cushioning by detecting the vehicle state and parking brake status in advance, and prohibiting motor actuation before any potential disengagement of the locking pin can occur. This preventive measure ensures that the frictional resistance is never overwhelmed by excessive torque.
3Reliability
If the brake controller prohibits the electric motor from actuating when the vehicle is stopped and parking brake operation is complete, then the parking brake is maintained, but the service brake control is restricted
Solution Approach 1:
The brake control system dynamically adapts its behavior based on the vehicle state and parking brake status. When the vehicle is stopped and parking brake is applied, the motor actuation is prohibited to maintain parking brake reliability. However, when the vehicle is moving or parking brake is not applied, the motor can be actuated for normal service braking. This dynamic adaptation ensures both parking brake maintenance and service brake functionality are preserved in their respective operating conditions.
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
Prevents untimely release of the parking brake, ensuring vehicle safety by maintaining the braking force even when the brake pedal is operated unintentionally, and allowing service braking when the vehicle is not stopped.
Implementation Method 1
the locking pin is kept engaged in the engaging hole by the frictional resistance generated between the intermediate gear and the locking pin due to the reaction force torque
Implementation Method 2
an electric motor, a braking mechanism configured to press a friction pad against a rotor which rotates together with a wheel of a vehicle, under the power of the electric motor, thereby applying a braking force to the wheel
Data Source
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AI summary
An electric brake system with a parking function is provided which is capable of preventing untimely release of the parking brake if the brake pedal is operated when the parking brake operation has completed. The electric brake system includes a service brake control means for actuating an electric motor (1) when a brake pedal (81) is operated, a parking brake control means configured, when there exists a request to apply a parking brake, to actuate the electric motor (1), and with the motor (1) being actuated, move a locking pin (65) from an unlocking position to a parking/locking position, and a motor actuation prohibiting means for prohibiting the actuation of the electric motor (1) by the service brake control means even if the brake pedal (81) is operated, while the vehicle is determined to be at a stop and when the parking brake operation has stopped.