Vehicle Seat Slide Lock Stability Under Collision Load
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Solution Overview
Problem
Existing seat slide apparatuses for vehicles face issues with unstable rotation of the lock member and increased length and mass of the operation member, which can lead to unstable locking and unlocking of the relative movement between the lower and upper rails, especially under large loads such as those encountered in vehicle collisions.
Innovation Solution
A seat slide apparatus with a lock member that includes a shaft portion supported in bearing holes, a fracture opening to allow the shaft to shift from the bearing hole under load, and a restriction portion to prevent rotation and maintain the locked state, along with a flanged member to further restrict rotation and a biasing member to engage the lock portion with the locked portion, ensuring stable engagement and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lock member is configured with the attachment portion at the end away from the operation member to enable effective elastic deformation, then the locking reliability is improved, but the operation member becomes elongated increasing its length and mass
Solution Approach 1:
The patent inverts the conventional configuration by positioning the attachment portion at the end of the lock member away from the operation member, rather than at the end closer to the operation member. This inversion enables the lock member to be effectively elastically deformed during locking operations, improving locking reliability while allowing the operation member to be shorter and lighter than in conventional designs
2Stability of the object's composition
If the lock member is made with high rigidity material to maintain stable locking, then the locking stability is improved, but the operation member length and mass increase
Solution Approach 1:
The patent inverts the conventional configuration by positioning the attachment portion at the end of the lock member away from the operation member. This inversion allows the lock member to achieve stable locking through effective elastic deformation, eliminating the need for high rigidity materials and excessive operation member length while maintaining locking stability
3Stability of the object's composition
If the shaft portion is supported in bearing holes for stable rotation, then the rotation stability is improved, but the lock member becomes unstable under large loads
Solution Approach 1:
The patent introduces a movement allowing portion that enables the shaft portion to dynamically shift its position relative to the bearing holes when large loads are applied. This dynamic adjustment allows the lock member to maintain rotation stability during normal operation while adapting to large loads by allowing controlled movement, preventing instability and maintaining locking reliability under collision conditions
Solution Approach 2:
The movement allowing portion acts as a pre-designed cushioning mechanism that anticipates large load conditions. By allowing the shaft portion to shift position beforehand through the movement allowing portion, the system prepares for collision loads, preventing instability before it occurs and maintaining locking reliability under extreme conditions
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 solution stabilizes the locked state of the relative movement between the rails under load, prevents unstable rotation of the lock member, and maintains engagement between the lock and locked portions, enhancing the overall stability and reliability of the seat slide mechanism.
Implementation Method 1
a lock member (30) rotatably connected to the upper rail (4) by a shaft portion (22) supported by bearing holes (17)
Implementation Method 2
a biasing member (50) biasing the lock member (30) to rotate in a direction in which the relative movement between the lower rail (3) and the upper rail (4) is brought in the locked state
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A seat slide apparatus for a vehicle includes a first rail (3) including a locked portion (13c), a second rail (4) movably connected relative to the first rail (3) and including bearing holes (17), a lock member (30) including a lock portion (37) and rotating around the bearing holes (17) to engage the lock portion (37) with the locked portion (13c) and disengage the lock portion (37) from the locked portion (13c) to selectively bring a relative movement between the first rail (3) and the second rail (4) into a locked state, and wherein the second rail (4) includes a fracture opening (18, 71) allowing the shaft portion (22) to shift from the bearing hole (17) in a case where a load is inputted in the direction of the relative movement, and a restriction portion (19b) configured to restrict the lock member (30) from rotating in a direction in which the locked state is released in a case where the shaft portion (22) shifts from the bearing hole (17).