Vehicle Door Latch Reset Circuit for Quiet Power-Off Return
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Solution Overview
Problem
Current closure latch assemblies in motor vehicles face issues with noise and excessive friction during power reset operations, and loss of power can prevent non-powered reset functions, compromising system efficiency and complexity.
Innovation Solution
A closure latch assembly with a power-operated actuator and a reset mechanism that includes an electric motor, gear reduction unit, coil spring, drive pulley, arbor, and drive cable, allowing for non-powered reset functionality through a spring-loaded and spring-released mechanism, and an electronic reset circuit with energy storage for powered reset operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a power-operated actuator is used to shift the actuatable mechanism, then the actuation function is improved, but noise and excessive friction occur during power reset operations
Solution Approach 1:
The reset function is segmented from the power actuation system into a separate non-powered reset mechanism. This allows the power actuator to perform only its primary actuation function without the harmful effects of powered reset operations, while the dedicated reset mechanism handles the reset function using passive spring energy.
Solution Approach 2:
The reset function is extracted from the powered actuation system and implemented as a separate non-powered mechanism. This extraction eliminates the noise and friction associated with powered reset operations while preserving the actuation capability.
2Device complexity
If a non-powered reset mechanism is implemented, then system complexity is reduced, but loss of power can prevent reset operations
Solution Approach 1:
Energy is stored in the spring mechanism during the actuation phase (when power is available), preparing the system for reset operations. This preliminary energy storage ensures that reset operations can proceed reliably even when power is subsequently lost.
Solution Approach 2:
The reset mechanism is designed to be self-service through the spring-loaded mechanism that automatically provides the necessary force for reset operations without requiring external power, thereby maintaining reliability during power loss.
3Force
If large reset springs and high gear ratios are used to provide reset force, then the reset function is ensured, but device complexity and size increase
Solution Approach 1:
The spring mechanism parameters (spring constant, pre-compression) are optimized to provide sufficient reset force without requiring excessive spring size. This parameter optimization allows the system to achieve the necessary force while maintaining compact dimensions and reduced complexity.
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 solution provides a quiet, efficient non-powered reset function and ensures uninterrupted operation even without primary power, enhancing system reliability and reducing complexity by eliminating the need for large reset springs and high gear ratios.
Implementation Method 1
The reset mechanism is operable in a spring-loaded state when the actuatable mechanism is shifted into its actuated state and is further operable in a spring-released state when the electric motor is operating in a non-powered state
Data Source
AI summary
The present disclosure relates to a closure latch assembly for a vehicle door, and more particularly to a closure latch assembly for a vehicle door equipped with a powered reset feature. To this end, the present disclosure relates to the use of a power actuator to actuate an actuatable mechanism in a power-on state, and an electronic reset circuit mechanism to reset the actuatable mechanism when the power actuator is in a power-off state. The electronic reset circuit mechanism is coupled to an electric motor associated with the power actuator.