Brake Actuator Ratchet Locking for Parking Brake Readjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The self-releasing nature of electromechanical vehicle brakes leads to a weakening of the braking force when the vehicle is parked, as the tension force decreases due to cooling, and the blocking lever must be released to readjust the braking force, resulting in a potential further weakening of the braking force during this time window.
Innovation Solution
A brake actuator with an electric motor and a blocking module that includes a pivotable blocking lever with a blocking tooth, which engages with a gear wheel to implement a ratchet function, ensuring the vehicle brake cannot be released further while allowing the braking force to be readjusted without activating the blocking actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blocking lever is released to readjust the braking force, then the braking force can be restored, but the vehicle brake may be inadvertently released further causing loss of parking brake function
Solution Approach 1:
The blocking tooth is designed with asymmetric geometry: one flank has blocking geometry that prevents rotation in the releasing direction, while the opposite flank has lifting geometry that allows rotation in the boosting direction. This asymmetric design enables readjustment of braking force while preventing inadvertent release of the parking brake.
Solution Approach 2:
The blocking lever is made resiliently mountable rather than rigidly fixed, allowing it to dynamically adapt between blocking and lifting positions based on motor rotation direction. The resilient mounting enables the blocking lever to be lifted by the lifting geometry during boosting while maintaining blocking function during releasing.
2Productivity
If the blocking lever is held in releasing position during readjustment, then the electric motor can rotate freely, but the braking force may further weaken due to self-releasing nature
Solution Approach 1:
The blocking tooth geometry asymmetrically permits motor rotation in the boosting direction (via lifting geometry) while blocking rotation in the releasing direction (via blocking geometry). This allows rapid readjustment without risking further braking force weakening.
Solution Approach 2:
The blocking lever acts as an intermediary mechanism between the electric motor and the parking brake locking function. It mediates by selectively allowing or preventing motor rotation based on the rotation direction, enabling controlled readjustment while maintaining parking brake integrity.
3Ease of operation
If a conventional blocking actuator is used to release the blocking lever, then the blocking lever can be released, but the actuator must be switched on and off creating operational complexity
Solution Approach 1:
The blocking lever is designed to be automatically released by the lifting geometry when the electric motor rotates in the boosting direction. The motor's own rotation drives the blocking lever release without requiring separate actuator activation, simplifying the control system.
Solution Approach 2:
The lifting geometry is pre-configured on the blocking tooth to automatically engage and lift the blocking lever when the motor begins rotating in the boosting direction. This preliminary geometric arrangement eliminates the need for active actuator control during readjustment.
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 ensures that the vehicle brake remains engaged and the braking force can be readjusted without inadvertently releasing the brake, thereby maintaining the integrity of the parking brake function and preventing further weakening of the braking force.
Implementation Method 1
a spring (52) for applying to the blocking lever (40) a pre-loading force in the direction of the locking position
Implementation Method 2
the blocking tooth on one tooth flank has a blocking geometry, and on an opposite tooth flank has a lifting geometry, said geometries being configured in such a manner that in a rotation of the electric motor in a first direction that boosts a braking force, the blocking lever by the rotation of the electric motor is lifted counter to a spring force so as to disengage from the gear wheel
Data Source
AI summary
Specified is a brake actuator (12), in particular for an electromechanical vehicle brake (10), having an electric motor (32) for activating the vehicle brake (10), and a blocking module (36) for selectively rotationally blocking an output shaft (38) of the electric motor (32) so as to configure a parking brake function. The blocking module (36) comprises a blocking lever (40) which is mounted so as to be pivotable between a locking position and a releasing position, and a blocking actuator (42) for pivoting the blocking lever (40), wherein configured on the blocking lever (40) is a blocking tooth (44) which in the locking position of the blocking lever (40) engages with a gear wheel coupled to the output shaft (38) of the electric motor (32). The blocking tooth (44) on one tooth flank (60) has a blocking geometry (61), and on an opposite tooth flank (62) has a lifting geometry (63), said geometries (61, 63) being configured in such a manner that in a rotation of the electric motor (32) in a first direction that boosts a braking force, the blocking lever (40) by the rotation of the electric motor (32) is lifted counter to a spring force so as to disengage from the gear wheel, and a rotation of the electric motor (32) in an opposite direction that releases the braking force is blocked. A vehicle brake (10) is furthermore specified.