Powerfold Mirror Actuator With Variable Axial Biasing Force
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle exterior rearview mirror and door handle assemblies lack efficient mechanisms for smooth and reliable movement between extended and folded positions, particularly in handling ice buildup and maintaining clearance to prevent damage and noise.
Innovation Solution
The use of non-linear compression mechanisms with torsion springs and variable torque biasing mechanisms that apply axial and torque forces to facilitate smooth movement and maintain clearance, providing greater force at the beginning of the range of motion to overcome obstacles like ice buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a powerfold actuator is used to move the mirror head between extended and folded positions, then the mirror assembly can be automatically positioned, but the mechanism experiences increased strain and potential damage due to ice buildup and lack of clearance maintenance
Solution Approach 1:
The biasing mechanism applies preliminary force to the mirror head before the actuator initiates movement, pre-positioning the mirror head to maintain proper clearance and overcome ice buildup before automated operation begins, thereby reducing strain on the actuator during operation
Solution Approach 2:
The biasing mechanism acts as an intermediary between the actuator and the mirror head, providing auxiliary force that complements the actuator's automated operation. This intermediary mechanism handles the challenging aspects of movement (overcoming ice, maintaining clearance) while the actuator handles the automated positioning function
2Device complexity
If the mirror head moves between extended and folded positions without a biasing mechanism, then the structure is simpler, but the movement is less smooth and clearance is not maintained, causing noise and potential damage
Solution Approach 1:
The biasing mechanism is self-regulating, automatically applying and releasing force as the mirror head moves through its range of motion. The mechanism services itself by using the mirror head's own movement to compress and decompress the biasing element, eliminating the need for additional control systems while maintaining smooth operation
Solution Approach 2:
The biasing mechanism dynamically changes the force parameter applied to the mirror head during movement. By varying the biasing force as the mirror transitions between positions, the system achieves smooth operation and maintains clearance without requiring complex control systems
3Ease of operation
If a variable force biasing mechanism is added to apply axial biasing force along the pivot tube, then the mirror head moves more smoothly with maintained clearance, but the device complexity increases
Solution Approach 1:
The biasing mechanism introduces a new dimensional aspect to the mirror assembly by adding axial force along the pivot tube's longitudinal axis. This additional dimensional force component enables smooth movement and clearance maintenance without requiring complex multi-axial mechanisms in the traditional rotational plane
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
These mechanisms ensure reliable and smooth operation of the mirror and handle assemblies by providing increased force to overcome initial obstacles, reducing strain on actuators and preventing damage, while also reducing noise and debris entry.
Implementation Method 1
The variable force biasing mechanism includes a torsion spring that biases the second portion of the variable force biasing mechanism along the longitudinal axis of the pivot tube to apply the axial biasing force between the mounting base and the mirror head along the longitudinal axis of the pivot tube
Implementation Method 2
The variable torque biasing mechanism includes a compression spring that biases the third portion of the variable torque biasing mechanism about the longitudinal axis of the first portion to bias the handle portion relative to the base portion from the recessed position toward the deployed position
Data Source
AI summary
A vehicular exterior rearview mirror assembly includes a mirror head accommodating a mirror reflective element. An actuator is electrically operable to move the mirror head relative to a mounting base between a folded position and an extended position. The actuator includes a base portion that attaches at the mounting base and a pivot tube that extends from the base portion. The actuator includes a biasing mechanism that, when the mirror moves between the extended and folded positions, biases the mirror head relative to the mounting base in a direction parallel to a longitudinal axis of the pivot tube. The biasing mechanism includes a shell fixed relative to the mounting base, a longitudinally movable portion coupled to the mirror head and a torsion spring that biases the longitudinally movable portion in the direction parallel to the longitudinal axis.