Electric Brake Actuator Torque Control Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The uncertainty in the magnitude of torque imparted to the input shaft in electric brake actuators when the retained-position-change allowing mechanism operates can lead to inadequate functioning of the torque imparting device, reducing the actuator's utility, especially when the piston is at a standby position with a small torque.
Innovation Solution
Incorporating a lower-limit torque ensuring mechanism that prohibits the elastic torque of the torsion spring from becoming smaller than a set lower-limit torque, ensuring stable torque impartation to the input shaft even when the retained-position-change allowing mechanism operates, thereby enhancing the actuator's utility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the retained-position-change allowing mechanism operates to decrease elastic torque when it exceeds an upper-limit torque, then the torque imparting device can prevent excessive torque, but the set torque imparted to the input shaft becomes uncertain and may become considerably small, causing inadequate functioning
Solution Approach 1:
The patent applies parameter changes by introducing a lower-limit torque ensuring mechanism that maintains the elastic torque of the torsion spring within a specific range (between lower-limit and upper-limit torque). This mechanism includes a lower-limit retaining portion that retains the first retained portion when the elastic torque becomes smaller than the lower-limit torque, thereby ensuring the torque imparting device always imparts sufficient torque to the input shaft for reliable piston retraction and adequate functioning.
2Adaptability or versatility
If the elastic torque of the torsion spring is allowed to vary freely, then the torque imparting device can adapt to different braking conditions, but the torque becomes uncertain when the retained-position-change allowing mechanism operates, reducing actuator utility
Solution Approach 1:
The patent implements feedback control through the lower-limit torque ensuring mechanism. When the elastic torque of the torsion spring decreases below the lower-limit torque, the lower-limit retaining portion detects this condition and retains the first retained portion, thereby increasing the elastic torque back to the acceptable range. This feedback mechanism ensures the torque imparting device maintains reliable actuator utility while still adapting to different braking conditions within the controlled torque range.
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
The lower-limit torque ensuring mechanism stabilizes torque impartation to the input shaft, ensuring the actuator's high utility by maintaining a consistent torque for retracting the piston, even without relying on the electric motor, thus preventing inadequate functioning due to uncertain torque levels.
Implementation Method 1
a torque imparting device including a torsion spring and configured to impart, to the input shaft, a torque in a direction in which the piston retracts, in dependence on an elastic torque generated by the torsion spring
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An electric brake actuator configured to push a friction member onto a rotary body by advancing a piston by rotating an input shaft by an electric motor, including: a torque imparting device configured to impart, to an input shaft, a torque in a direction to retract a piston based on an elastic torque of a torsion spring (86) and including a mechanism configured to allow a first retained portion (104) provided at one end portion (102) of the torsion spring to be retained by another one of a plurality of first retaining portions of a stator (82) when the elastic torque exceeds a set upper-limit torque to decrease the elastic torque; and a mechanism configured to permit a second retained portion (116) of a rotor (84) to be retained by a second retaining portion (114) provided at the other end portion of the spring to prohibit the elastic torque from becoming smaller than a set lower-limit torque.