Vehicular Door Latch Rotation Member Interlock
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Solution Overview
Problem
Existing vehicular door latch devices fail to prevent the locking and unlocking mechanism from switching from the unlocked state to the locked state when the door is at a half-closed position, leading to unintended locking during simultaneous door closing and locking operations.
Innovation Solution
The vehicular door latch device incorporates a ratchet and interlock system with a rotation mechanism, where a detection lever inhibits posture change from the unlocked to the locked state when the door is half-closed, and allows change when fully closed, using a contact member and urging member to ensure correct locking and unlocking states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the locking and unlocking mechanism is allowed to switch freely between unlocked and locked states, then the ease of operation is improved, but the reliability deteriorates due to unintended locking at half-closed positions
Solution Approach 1:
The rotation member is positioned in advance on the posture switching route to block the transition from unlocked to locked state when the latch is at the half-closed position. This preliminary positioning prevents unintended locking before it can occur, while allowing normal operation when the door is fully closed.
2Measurement precision
If a detection lever is used to detect door position, then the measurement precision is improved, but the device complexity increases due to additional components and mechanisms
Solution Approach 1:
The detection lever is merged with the existing latch mechanism, utilizing the same rotational movement and structural components. The detection lever's position is directly derived from the latch's angular position, eliminating the need for separate detection systems and reducing overall device complexity.
Solution Approach 2:
The latch mechanism serves multiple functions: it not only engages and disengages the door but also detects door position through the detection lever. This multi-functionality reduces the need for additional components, as the same mechanical structure provides both latching and detection capabilities.
3Reliability
If the rotation member blocks the posture switching route at half-closed position, then the reliability is improved by preventing unintended locking, but the ease of operation deteriorates due to restricted movement
Solution Approach 1:
The rotation member's blocking action is dynamic rather than static. When the door is fully closed, the rotation member naturally moves away from the posture switching route, allowing free operation. The blocking only occurs temporarily at the half-closed position, creating a dynamic control mechanism that adapts to door position.
Solution Approach 2:
The rotation member applies preliminary anti-action by blocking the posture switching route before the locking mechanism can transition to the locked state at the half-closed position. This preemptive blocking prevents the harmful action (unintended locking) while allowing normal operation when the door is fully closed.
Data Source
AI summary
A vehicular door latch device includes a latch, a ratchet, a locking and unlocking mechanism, and a rotation member. The latch rotates in accordance with closing of a door while a striker provided in a vehicle body is engaged. When the door is in a fully-closed state, the ratchet holds the latch in a first posture. When the door is in a half-closed state, the ratchet holds the latch in a second posture. The mechanism is switched between an unlocked posture that can cancel interlock, and a locked posture that cannot cancel the interlock. When the latch is in the second posture, the rotation member overlaps the switching route and prohibits the posture change. When coming into contact with the rotation member overlapping the switching route, the mechanism in the unlocked posture is switched to the unlocked posture by rotation of a portion thereof in contact with the rotation member.