Electromechanical Drum Brake Stop Design for Precise Release Positioning
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Solution Overview
Problem
Current electrically actuated automobile vehicle brakes suffer from lack of compactness and accuracy in controlling the brake components, leading to increased size and longer brake application times due to inaccuracies in estimating the position of mechanical elements during the release phase.
Innovation Solution
Incorporating a mechanical stop within the electric actuator allows for precise control of movable elements during the brake release phase, ensuring accurate positioning and eliminating the need for error and safety margins, thereby optimizing the brake's dimensions and reducing application time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the position of mechanical elements is estimated during brake release phase without mechanical stop, then the brake system has simpler structure, but the positioning accuracy deteriorates and error margins must be incorporated
Solution Approach 1:
The mechanical stop serves itself as both a positioning reference and a control element. It provides the absolute reference position for the movable element during brake release, eliminating the need for external sensors or complex estimation algorithms. The stop structure is integrated into the actuator body, making the system self-sufficient for positioning accuracy.
Solution Approach 2:
The patent replaces electronic estimation methods (current/voltage sensing, revolution counting) with a mechanical reference system. The mechanical stop provides direct physical contact and absolute positioning, substituting complex electronic measurement and estimation systems with a simple mechanical reference that is inherently accurate and reliable.
2Reliability
If error and safety margins are incorporated in brake dimensioning to account for position inaccuracy, then the reliability improves, but the brake size increases
Solution Approach 1:
The mechanical stop is pre-positioned at the exact desired location within the actuator. This preliminary positioning action ensures that the movable element reaches the correct position without requiring additional safety margins or error buffers. The stop is manufactured at its final, precise location, eliminating the need for dimensional compensation.
Solution Approach 2:
The patent changes the positioning parameter from an estimated value with error margins to an absolute mechanical reference. By using the mechanical stop as a fixed physical reference point, the positioning parameter becomes deterministic rather than probabilistic, allowing for precise dimensioning without error margins.
3Reliability
If the stroke is lengthened to account for position uncertainty, then the safety margin improves, but the brake application time increases
Solution Approach 1:
The mechanical stop is pre-positioned to define the exact endpoint of the brake application stroke. This preliminary action establishes a precise stop point that prevents component abutting without requiring an extended stroke. The stop is placed at the optimal location that provides both safety and time efficiency.
Solution Approach 2:
The mechanical stop provides immediate physical feedback when the movable element reaches the correct position. This feedback mechanism (mechanical contact) automatically terminates the stroke at the precise moment needed, eliminating the need for extended strokes as a safety measure and reducing brake application time.
4Object-generated harmful factors
If the actuator operates without mechanical stop reference, then the device complexity is reduced, but the noise and discomfort duration increases
Solution Approach 1:
The mechanical stop is pre-positioned to define the exact endpoint of the actuator stroke. This preliminary action ensures that the actuator stops precisely when the brake is fully applied, preventing prolonged operation that would generate unnecessary noise and discomfort. The stop is manufactured at the optimal location to minimize harmful effects.
Solution Approach 2:
The mechanical stop provides immediate physical feedback that terminates the actuator operation at the correct moment. This feedback mechanism prevents the actuator from continuing to operate beyond the necessary stroke, thereby reducing noise generation and driver discomfort duration without requiring complex electronic 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
The implementation of a mechanical stop in the electric actuator enhances the accuracy and compactness of the brake system, reducing the stroke required for brake application, shortening the application time, and minimizing noise and discomfort during operation.
Implementation Method 1
an electric motor configured to activate the actuator
Implementation Method 2
said actuator including at least one mechanical stop, said actuator being controlled in the brake release phase so that at least one of the movable elements of the actuator bears against the stop
Implementation Method 3
at least one frictional member for contacting a friction part rotatably integral with the wheel... apply said frictional member against said friction part
Data Source
AI summary
An electromechanical drum brake comprises two brake segments intended to come into contact with a drum, and at least one actuator configured to apply the segments against the drum, and an electric motor configured to activate the actuator, the actuator comprising at least one member which is movable upon activation of the actuator, the movable member being movable between a braking position and a position beyond a release position, in which the segments are no longer in contact with the drum. The actuator comprises a stop which is arranged only in the actuator and against which the movable element bears when it assumes a position beyond the release position, and the motor powers the actuator until the movable element bears against the stop.