Seat Slide Apparatus Impact Load Path Redirection
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Solution Overview
Problem
Conventional electrically operated seat slide apparatuses face issues such as bending and buckling of load receiving members, increased part count, and difficulty in reducing the sectional area of the upper rail due to internal lead screw placement, which affects assembly workability and weight reduction.
Innovation Solution
An electrically operated seat slide apparatus with a U-shaped lower rail and reversed U-shaped upper rail, featuring a screw shaft and nut connection, where first and second plates allow direct impact load transmission to the screw shaft, preventing transmission through the gearbox, and using an elastic body and reinforcement plates to manage movement and absorb impacts without buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a load receiving member is fixed to the upper rail to transmit impact loads, then the impact load can be transmitted to the screw shaft, but the load receiving member is bent and gets off from the upper rail due to axial compression
Solution Approach 1:
The invention changes the load transmission path from a linear axial path through the screw shaft to a distributed path through multiple reinforcement plates positioned at different locations. The first reinforcement plate is positioned between the upper rail and the screw shaft, while the second reinforcement plate is positioned between the screw shaft and the lower rail, creating a multi-dimensional load distribution system that prevents concentration of compressive forces on single components.
Solution Approach 2:
The invention introduces reinforcement plates as intermediary components between the upper rail, screw shaft, and lower rail. These plates serve as mediators that distribute and redirect impact loads, preventing direct axial compression of the screw shaft and load receiving member while ensuring reliable load transmission to the structure.
2Force
If two flanges are fixed on the screw shaft with a load receiving member between them, then the screw shaft can receive compression loads, but the screw shaft buckles when receiving compression
Solution Approach 1:
The invention positions reinforcement plates at multiple locations along the screw shaft axis and distributes them radially around the screw shaft. This multi-dimensional arrangement provides lateral support to the screw shaft, preventing buckling under compression loads while maintaining the ability to transmit axial forces.
Solution Approach 2:
The invention creates a composite structural system combining the screw shaft, reinforcement plates, upper rail, and lower rail into an integrated load-bearing assembly. The reinforcement plates act as stiffening elements that composite with the screw shaft to increase its buckling resistance without requiring the screw shaft itself to be made of heavier material.
3Ease of operation
If the rail-side stopper is caulked to fix the nut member, then the nut member can be restrained, but the rail-side stopper is compressed and buckled to be bent
Solution Approach 1:
The invention positions the first reinforcement plate between the upper rail and the screw shaft, and the second reinforcement plate between the screw shaft and the lower rail, creating lateral support structures that prevent the stopper from buckling under compression during the caulking process while still allowing effective restraint of the nut member.
4Volume of moving object
If the lead screw is disposed inside the upper rail, then the structure is compact, but the sectional area of the upper rail cannot be reduced due to the need for internal support structures
Solution Approach 1:
The invention merges the reinforcement function with the existing structural components by positioning reinforcement plates at strategic locations within the available space. The first reinforcement plate is positioned between the upper rail and screw shaft, and the second reinforcement plate is positioned between the screw shaft and lower rail, combining structural reinforcement with the compact internal arrangement without requiring additional external support structures.
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 effectively prevents impact loads from being transmitted through the gearbox, reduces the risk of screw shaft buckling, and enhances assembly workability by minimizing the upper rail's sectional area, achieving a smaller and lighter design while maintaining durability.
Implementation Method 1
A screw shaft is disposed inside the upper rail and extends in a direction of length of the upper rail. A nut is threadedly connected to the screw shaft
Implementation Method 2
an elastic body and reinforcement plates to manage movement and absorb impacts without buckling
Data Source
AI summary
An electrically operated seat slide apparatus includes a lower rail fixed to a floor of a vehicle body, and an upper rail slidably disposed to the lower rail. A seat is connected to the upper rail. A screw shaft is disposed inside the upper rail. A nut is threadedly connected to the screw shaft and connected to the lower rail. A motor is disposed to side of the upper rail. A gear box is fixed to the upper rail to transmit a rotation of the motor to the screw shaft. Additionally, first and second plates are provided for allowing an impact load applied to the upper rail to be directly transmitted to the screw shaft so as to prevent the impact load from being transmitted through the gear box to the screw shaft, and for setting a moving range of the nut.