Unidirectional Power Latch Gear Mechanism
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Solution Overview
Problem
Current power actuated latch assemblies in motor vehicles face challenges in achieving efficient, quick, and reliable operation while minimizing noise and complexity, and there is a need for enhanced functionality that addresses limitations in existing systems.
Innovation Solution
A power latch assembly with a pawl movable between ratchet holding and releasing positions, utilizing a unidirectional power release actuator and gear system that includes circumferentially offset cog members to facilitate efficient movement and noise reduction, allowing the closure panel to transition from a closed to open position and back, with minimal rotational movement of the power release gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bi-directional power actuated latch assemblies are used, then the latch can be released and reset, but the system requires reverse motor circuitry and complex control mechanisms that increase device complexity and noise
Solution Approach 1:
Instead of using a bi-directional motor that can rotate clockwise and counter-clockwise to control the pawl, this invention uses a unidirectional motor that only rotates in one direction (e.g., counter-clockwise). The motor is coupled with a gear train including a first gear and a second gear that are selectively engageable with a pawl release gear. By controlling which gear is engaged, the system achieves both latch release and reset functions using only unidirectional motor rotation, thereby eliminating the need for complex reverse circuitry and control mechanisms.
2Ease of operation
If traditional power actuated latch assemblies operate, then the latch can be actuated, but noise is generated by the motor and moving components during operation
Solution Approach 1:
The patent inverts the traditional approach by using a unidirectional motor instead of a bi-directional motor. This unidirectional motor, combined with the selective gear engagement mechanism, reduces the number of moving parts and control reversals required during operation. The motor only needs to rotate in one direction to perform both release and reset functions, significantly reducing operational noise while maintaining full functionality.
3Productivity
If quick and efficient latch operation is achieved, then the latch responds rapidly to actuation commands, but this may increase wear on components and reduce durability
Solution Approach 1:
The patent employs a dynamic gear selection mechanism where the first gear and second gear can be selectively engaged with the pawl release gear based on the operational state. This dynamic engagement allows the system to achieve rapid actuation when needed while distributing the mechanical stress across different gear teeth and contact points. The selective gear engagement prevents any single set of gear teeth from experiencing excessive wear during repeated quick operations, thereby maintaining component durability.
Data Source
AI summary
A power latch assembly for a motor vehicle includes a pawl moveable from a ratchet holding position, whereat a ratchet is maintained in a striker capture position, whereat the ratchet is in latched engagement with a striker to maintain a closure panel in a closed position, to a ratchet releasing position, whereat the ratchet is moved to a striker release position out of latched engagement from the striker to allow the closure panel to be moved from the closed position to the open position. Further included is a power release actuator arranged to move a power release gear in a first direction from a rest position, whereat the pawl is in the ratchet holding position, to a first release actuated position, whereat the pawl is moved to the ratchet releasing position, and to move the power release gear from the first release actuated position in the first direction to a first reset actuated position, whereat the pawl is free to return to the ratchet holding position.