Seat Track Stopper Geometry for Steel Ball Retention
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Solution Overview
Problem
Conventional seat tracks face issues with steel balls excessively falling into stoppers during assembly due to varying diameters, leading to difficulties in inserting the retainer between the rails.
Innovation Solution
The seat track design includes a configuration where the distance between steel ball centers (L1) is greater than or equal to the distance between hole inner walls (L2), preventing all steel balls from falling into the stopper, and utilizing a lock lever and biasing member to manage the sliding and locking positions of the rails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the hole diameter is increased to accommodate steel balls with varying diameters, then the ease of assembly is improved, but the risk of steel balls excessively falling into the stopper increases
Solution Approach 1:
The patent changes the geometric parameters of the stopper structure by defining specific dimensional relationships between the hole diameter (D), stopper main body length (a), and steel ball diameter (φ). By setting D≥φ and a≥(D-φ)/2, the design optimizes the balance between assembly ease and preventing excessive ball insertion, resolving the contradiction through parameter optimization rather than structural redesign
2Reliability
If the retainer is press-fitted during assembly, then the steel balls are securely held, but the complexity of the assembly process increases
Solution Approach 1:
The patent incorporates preliminary design features into the stopper structure, specifically the dimensional relationships between the hole, stopper main body, and steel balls. These pre-designed geometric constraints guide the assembly process and ensure proper positioning without requiring complex assembly procedures, thus maintaining reliability while reducing assembly complexity
3Reliability
If the stopper main body is bent after retainer press-fitting, then the stopper function is activated, but the assembly time is increased
Solution Approach 1:
The patent defines specific dimensional parameters for the stopper main body (length a≥(D-φ)/2) that enable the bending operation to be performed efficiently. These optimized parameters ensure that the stopper can be properly formed and activated with minimal additional assembly time, balancing the need for functional activation with production efficiency
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
This configuration ensures that steel balls do not excessively fall into the stopper during assembly and provides effective load distribution during collisions, reducing the likelihood of rail deformation and damage.
Implementation Method 1
at least two steel balls disposed between the first rail and the second rail, the steel balls relative-slidably supporting the second rail with respect to the first rail
Data Source
AI summary
A seat track includes a stopper. The stopper includes a hole formed in a first rail and a stopper main body that projects in a direction of intersecting with a relative sliding direction of a second rail from an edge portion of the hole and is configured to restrict a move of a retainer. When a distance between centers of two steel balls disposed at both ends in the relative sliding direction of the second rail is L1 among steel balls and a distance between inner walls of the hole in the relative sliding direction of the second rail is L2, L1≥L2.