Vehicle Recliner Lock Mechanism Energy Absorption
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Solution Overview
Problem
Existing vehicle seat recliners lack an energy-absorbing structure to manage excessive loads during collisions, leading to potential damage to the lock mechanism when a large load is applied.
Innovation Solution
Incorporating guide walls with weak portions that undergo plastic deformation to absorb energy, allowing the recliner to maintain the locked state under high loads without damaging the pawl mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the structural strength of the lock mechanism is increased to maintain the locked state under large loads, then the reliability is improved, but the device complexity and weight increase
Solution Approach 1:
The guide wall is segmented into a strong portion and a weak portion, allowing different regions to serve different functions. The strong portion maintains structural integrity for normal operation, while the weak portion provides controlled deformation for energy absorption during collisions, avoiding the need to strengthen the entire lock mechanism.
Solution Approach 2:
Instead of uniformly increasing the strength of the entire lock mechanism, the patent applies local quality by creating a weak portion only in specific areas of the guide wall where controlled deformation is desired. This allows the majority of the lock mechanism to maintain its original simple structure while providing reliability where needed.
2Ease of operation
If the guide walls are made more rigid to better support the pawl, then the ease of operation is improved, but the ability to absorb energy during collisions deteriorates
Solution Approach 1:
The guide wall is divided into a strong portion for supporting the pawl during normal operation and a weak portion for energy absorption during collisions. This segmentation allows the guide wall to provide rigid support when needed while maintaining the capability to deform and absorb energy when subjected to large loads.
Solution Approach 2:
The patent changes the structural parameter of the guide wall by creating a weak portion with reduced thickness or strength characteristics. This parameter change allows the guide wall to transition from a purely rigid structure to one that can exhibit both rigid support behavior during normal operation and flexible deformation behavior during collisions.
3Loss of energy
If the weak portion is located closer to the contact face to improve energy absorption, then the energy absorption capability is improved, but the rigidity for normal operation deteriorates
Solution Approach 1:
The weak portion is strategically positioned in a specific location on the guide wall where it can effectively absorb energy without compromising the overall rigidity. The local quality change is applied only where needed for energy absorption, while the rest of the guide wall maintains its full strength for supporting the pawl during normal operation.
Solution Approach 2:
The weak portion is pre-positioned in the guide wall structure during manufacturing, ready to undergo deformation when and if a collision occurs. This preliminary preparation allows the guide wall to maintain its rigid structure during normal use while having the capability to absorb energy through controlled deformation of the weak portion when subjected to large loads.
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
The recliner effectively absorbs energy by deforming guide walls, maintaining the locked state and preventing damage to the pawl mechanism, even under large loads, thereby enhancing structural integrity and safety during collisions.
Implementation Method 1
The weak portion is adapted to undergo local stress concentration and plastic deformation due to pressing force received from the pawl when a large load that causes the pawl to undergo forced deformation in the circumferential direction is applied.
Implementation Method 2
The weak portion is adapted to undergo local stress concentration and plastic deformation due to pressing force received from the pawl
Data Source
AI summary
A recliner has a ratchet and a guide assembled together so as to be rotatable relative to each other, and a pawl supported by the guide in a circumferential direction. The pawl is adapted to inhibit rotational movement of the ratchet relative to the guide when moved to be pushed radially outwards. The pawl is supported by guide walls formed in the guide, and the guide walls are located at circumferentially opposite sides of the pawl. Each guide wall has a recessed part (weak portion) formed at a location spaced in the circumferential direction apart from a contact face of the guide wall which is in contact with the pawl. The recessed part is adapted to undergo local stress concentration and plastic deformation due to pressing force received from the pawl when a large load that causes the pawl to undergo forced deformation in the circumferential direction is applied.