Motor Vehicle Latch with Cinch Lever for Crash Safety
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Solution Overview
Problem
Current power door latch assemblies for motor vehicles fail to maintain functionality and intended position during impacts or power loss, leading to unintended door opening, which poses safety concerns and requires additional features to ensure the door remains closed during crash conditions.
Innovation Solution
A power latch assembly with an auxiliary ratchet link and cinch mechanism that prevents inadvertent movement of the ratchet from a striker capture position to a release position upon impact or power loss, using a single motor to actuate the pawl for release and cinch operations, and a power release gear that drives the pawl and ratchet between capture and release positions, ensuring the door remains closed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional power actuated latch assembly is used, then the door can be opened and closed using power, but the latch fails to maintain its intended position during impacts or power loss, leading to unintended door opening
Solution Approach 1:
The latch assembly is segmented into multiple independent locking mechanisms: a primary pawl-ratchet system and a secondary cinch mechanism with cinch lever. Each segment provides a distinct locking function, ensuring that if one system fails during impact or power loss, the other maintains the door closed position.
Solution Approach 2:
The cinch mechanism is designed to automatically engage and cinch the ratchet into a secured position during normal door closing operation, before any impact or power loss occurs. This preliminary action ensures the latch is pre-positioned in a fail-safe state that prevents unintended opening.
2Reliability
If additional safety features are added to prevent unintended door opening during crash conditions, then safety is improved, but device complexity and cost increase
Solution Approach 1:
The cinch mechanism is integrated into the existing power actuated latch assembly, sharing common components such as the ratchet, pawl, and motor-driven actuator. This merging allows crash safety functionality to be added without requiring a completely separate system, thereby limiting the increase in overall complexity.
Solution Approach 2:
The single motor-driven actuator serves multiple functions: it operates the primary pawl-ratchet mechanism for normal door operation and simultaneously drives the cinch mechanism for crash safety. This multi-functionality reduces the need for additional dedicated components, minimizing complexity while improving safety.
3Device complexity
If a single motor is used to actuate both pawl release and cinch operations, then device complexity is minimized, but the mechanism must manage multiple positions and operations
Solution Approach 1:
The actuator system employs dynamic position detection and automatic state transitions. The motor-driven actuator continuously monitors the latch state and automatically adjusts its operation to manage the complex sequence of pawl release and cinch engagement, reducing the need for complex external control mechanisms.
Solution Approach 2:
The latch assembly incorporates automatic position sensing and self-regulating control. When the door is closed, the system automatically cinches the ratchet; when opening is detected, it automatically releases the pawl and engages the cinch mechanism, eliminating the need for complex manual control inputs.
Data Source
AI summary
A latch assembly and system therewith configured for retaining a closure panel of a motor vehicle in a closed position relative to a vehicle body during and upon the latch assembly experiencing an impact force during a crash condition and/or a power shortage to the latch assembly and prior to the latch assembly having been intentionally actuated to move to an unlatched state.