Vehicular Latch Roller Mechanism for Ratchet Position Detection
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Solution Overview
Problem
Current power-operated latch assemblies face challenges in accurately determining the position of the ratchet, leading to blind spots and malfunctions in the power cinching function, particularly when the door is in a partially closed state due to insufficient seal load, causing the controller to incorrectly identify the door state and fail to initiate the cinching process.
Innovation Solution
The proposed closure latch assembly incorporates a ratchet with an elongated edge profile and a cinch mechanism that uses a cinch lever and release lever to move the ratchet from a secondary to a primary striker capture position without direct latched engagement between the pawl and ratchet, eliminating the need for an additional pawl to maintain the secondary striker capture position, and includes sensors to accurately determine the ratchet's position for precise control of the cinching operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional ratchet/pawl latch mechanism is used, then the latch assembly can provide basic latching functionality, but the controller cannot accurately determine the ratchet position, causing blind spots in power cinching control
Solution Approach 1:
A roller member is introduced as an intermediary element between the pawl and ratchet. The roller member rotates as the ratchet moves between positions, providing a reliable mechanical indicator of ratchet position without requiring direct complex sensing of the ratchet itself. This mediator enables accurate position detection while maintaining relatively simple latch mechanism structure.
Solution Approach 2:
The patent replaces traditional mechanical position indication methods with a roller-based mechanical system that converts ratchet linear/rotational movement into rotational movement of the roller. This mechanical substitution provides reliable position feedback that can be detected by sensors, improving measurement precision without significantly increasing overall device complexity.
2Ease of operation
If the pawl directly engages the ratchet to hold it in secondary striker capture position, then the latch mechanism is simple, but the controller cannot distinguish between primary and secondary positions, causing power cinching malfunction
Solution Approach 1:
The latching function is segmented into distinct primary and secondary striker capture positions with different mechanical configurations. The roller member is positioned to engage with features on the ratchet that are specific to each position, allowing the controller to distinguish between them. This segmentation enables reliable power cinching operation by providing clear positional differentiation.
Solution Approach 2:
The roller member provides mechanical feedback about the ratchet's position through its engagement geometry. When the ratchet is in different positions (primary vs. secondary), the roller assumes different orientations or engagement states, which can be detected by position sensors. This feedback mechanism enables the controller to accurately determine when power cinching should be initiated or terminated.
3Measurement precision
If additional sensing mechanisms are added to detect ratchet position, then measurement precision improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The roller member serves as a mechanical intermediary that translates complex ratchet position information into simple, detectable signals. Instead of adding complex sensors directly to monitor ratchet position, the roller provides a mechanical interface that converts position data into easily detectable states (such as roller orientation or engagement with detection features), improving measurement precision while maintaining ease of manufacture.
Data Source
AI summary
A latch assembly for a motor vehicle closure system having a latch mechanism, a latch release mechanism and a power cinching mechanism. The latch mechanism is operable in a released state when a closure panel is located in an open position, in a secondary closed state when the closure panel is located in a partially-closed position, and in a primary closed state when the closure panel is located in a fully-closed position. The cinching mechanism interacts with the latch mechanism to establish the secondary closed state and is actuated for shifting the latch mechanism from its secondary closed state into its primary closed state.