Vehicle Seat Recliner Double Locking Against Collision Folding
Solution Overview
Problem
Existing reclining devices for vehicle seats inadvertently fold during vehicle collisions due to the cam unlocking from the first locking section.
Innovation Solution
A reclining device with a double locking mechanism, featuring a rotary bracket and cam with different pressure angles for the first and second locking sections, ensuring the cam remains locked in the second locking section during impacts, preventing inadvertent folding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single locking section is used in the reclining device, then the structure is simple, but the seatback may inadvertently fold during vehicle collisions due to cam unlocking
Solution Approach 1:
The locking mechanism is divided into two distinct locking sections: a first locking section for normal operation and a second locking section for impact protection. The cam can sequentially engage with both sections, creating a segmented locking system that provides different levels of security for different operating conditions.
Solution Approach 2:
The second locking section is pre-configured as a backup locking position before any collision occurs. The geometry of the second locking section is designed in advance with a smaller pressure angle to ensure that if impact forces cause the cam to disengage from the first locking section, it will automatically transition to and be retained in the second locking section.
2Reliability
If the pressure angle at the second locking section is made smaller to prevent inadvertent folding, then locking reliability during impact improves, but the locking force at the first locking section may be insufficient
Solution Approach 1:
Different pressure angles are assigned to different locking sections based on their specific functional requirements. The first locking section has a larger pressure angle (6-12 degrees) optimized for normal locking force, while the second locking section has a smaller pressure angle (0-5 degrees) optimized for impact resistance. This local differentiation allows each section to perform its specific function optimally.
Solution Approach 2:
The locking system transitions dynamically between two states: normal operation where the cam engages the first locking section with higher locking force, and impact protection where the cam engages the second locking section with lower pressure angle for enhanced stability during collisions. The system adapts its locking characteristics based on the operational condition.
Data Source
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AI summary
A reclining device for a vehicle seat, includes a rotary bracket having a center portion rotatably connected to a first frame and having a first locking section and a second locking section connected to the first locking section, and a cam configured to rotate about a center portion connected to the first frame and having a locking portion provided at one end thereof and positioned in the first locking section or the second locking section so as to be locked.