Vehicle Door Latch Power Shutoff Mechanism
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Solution Overview
Problem
Existing vehicle door latch devices face difficulties in locking the door in a fully closed state when the release motor abnormally stops in an unlatched position, preventing the door from being securely closed.
Innovation Solution
A vehicle door latch device with a pawl biasing member, a motor, and a release power transmitting unit that includes motor-side, relay, and pawl-side rotation boards, allowing manual switching to a latched position by moving the relay rotation board to a power shutoff position when the motor stops, enabling the pawl to return to a latched position and secure the door.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the release motor is used to rotate the pawl from the latched position to the unlatched position, then the door can be opened conveniently, but the door cannot be locked in a fully closed state when the motor stops abnormally in the unlatched position
Solution Approach 1:
The release power transmitting unit is divided into three independently rotatable components (motor-side rotation board, relay rotation board, pawl-side rotation board) that can be selectively connected or disconnected. This segmentation allows the system to switch between motor-driven operation and manual operation modes, resolving the contradiction between ease of operation and reliability.
Solution Approach 2:
The relay rotation board can dynamically change its position between a power transmission position (where it connects all three rotation boards) and a power shutoff position (where it disconnects the motor-side rotation board from the pawl-side rotation board). This dynamic reconfiguration enables the system to adapt to different operational states and recover from motor failures.
2Power
If the relay rotation board is positioned at the power transmission position to allow integral rotation of all components, then the motor can effectively drive the pawl, but the system cannot recover from abnormal motor stopping
Solution Approach 1:
The relay rotation board acts as an intermediary component that can be selectively engaged or disengaged from the power transmission path. When the motor fails, the relay rotation board can be manually moved to the power shutoff position, allowing the pawl to be independently rotated back to the latched position without being driven by the failed motor.
Solution Approach 2:
The long hole in the relay rotation board creates a localized region where the rotation board rotating pivot can move freely between two distinct positions. This local structural feature enables the relay rotation board to selectively establish or break power transmission connections, providing both efficient power transmission and failure recovery capabilities.
3Adaptability or versatility
If a long hole is formed in the relay rotation board to allow linear movement, then the relay rotation board can switch between power transmission and power shutoff positions, but the structure becomes more complex
Solution Approach 1:
The relay rotation board serves multiple functions: it transmits power when in the power transmission position, it allows manual intervention when in the power shutoff position, and it provides a mechanical interface for both motor-driven and manual operations. This multi-functionality justifies the additional structural feature of the long hole.
Solution Approach 2:
The rotation board rotating pivot is nested within the long hole of the relay rotation board, allowing the pivot to move linearly within the hole while maintaining rotational capability. This nested arrangement enables compact integration of linear and rotational movements without significantly increasing overall device 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
Enables manual locking of the door in a fully closed state even if the motor stops, ensuring the door can be securely held closed and providing a mechanism for abnormality notification, thus addressing the issue of motor failure.
Implementation Method 1
a pawl biasing member which biases the pawl to the latched position
Implementation Method 2
the latch and a pawl are pressed against each other by the reaction force to be frictionally engaged with each other. The frictional engagement becomes operation resistance when a handle of the door is operated.
Data Source
AI summary
A device includes a latch of a door and rotates while engaging with a striker of a vehicle body; a pawl which is rotatable between a latched position to restrict a rotation of the latch and a unlatched position to permit the rotation of the latch; a motor; a release power transmitting unit which transmits a rotational power of the motor to the pawl and rotates the pawl from the latched position to the unlatched position. The device further includes a motor-side rotation board, a relay rotation board, and a pawl-side rotation board, which are connected to be integrally rotatable. The relay rotation board become movable to a power shutoff position by pressing operation though an operating hole formed in a door. In the power shutoff position, connecting between the three boards is released, and the motor-side rotation board and the pawl-side rotation board become individually rotatable.