Vehicle Seat Longitudinal Adjuster With Self-Centering Spindle Nut Assembly
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Solution Overview
Problem
Existing longitudinal adjusters for vehicle seats face challenges in easily positioning and assembling the spindle nut, requiring active alignment and additional receptacles to compensate for production-related tolerances.
Innovation Solution
A longitudinal adjuster design featuring a spindle nut fixed by two fixing elements with conical transitions, allowing for perpendicular centering relative to the second rail, which simplifies the alignment and assembly process by using conical screws that deform the contact edges of the through openings for secure centering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fixing elements are used to secure the spindle nut to the second rail, then the spindle nut can be fastened, but active alignment and additional receptacles are required to compensate for production tolerances, increasing assembly complexity
Solution Approach 1:
The fixing element incorporates a conical transition region that deforms the contact edges of the through opening during insertion. This parametric geometric feature (conical shape) enables automatic compensation for production tolerances in the through opening dimensions and positioning, eliminating the need for additional alignment receptacles while ensuring reliable fastening of the spindle nut to the second rail
2Reliability
If traditional fixing elements are used to secure the spindle nut, then fastening is achieved, but the alignment process requires active intervention and additional receptacles, increasing manufacturing steps
Solution Approach 1:
The conical transition region of the fixing element performs self-alignment during the fastening process. As the fixing element is inserted through the through opening, the conical geometry automatically deforms the contact edges to compensate for tolerance variations, enabling the assembly to self-correct without requiring active alignment operations or additional alignment receptacles, thereby simplifying the manufacturing process
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 design enables easy compensation of production tolerances and secure fastening of the spindle nut, reducing the need for active alignment and additional receptacles, thereby simplifying the assembly process and enhancing the stability of the longitudinal adjuster.
Implementation Method 1
the conical transitions, which simplify the alignment and assembly process by using conical screws that deform the contact edges of the through openings for secure centering
Data Source
AI summary
A longitudinal adjuster having at least one rail pair, formed from a first rail and a second rail. The first and second rails are displaceable relative to each other and fit around each other to form an inner channel. A spindle nut is connected to the second rail and a spindle is operatively connected to the spindle nut and are arranged in the inner channel. The spindle nut is fixed on the second rail by a first fixing element and an second fixing element. The spindle nut is centered perpendicular to a longitudinal extent of the second rail by the two fixing elements. A method for assembling the longitudinal adjuster to a vehicle seat are described.