Seat Track Memory Mechanism for Low-Friction Position Return

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Solution Overview

Problem

Existing seat track assemblies for automotive vehicles face difficulties in efficient operation due to increased friction between the memory mechanism and the movable track, and imprecise engagement that makes it hard to return to the previously selected position after moving from the easy-entry position.

Innovation Solution

The seat track assembly incorporates a primary and secondary track system with a cross-talk cable, a U-shaped fixed track, an inverted U-shaped movable track, roller bearings, a latch mechanism, and a memory mechanism with a memory plate that engages with a tooth rack to accurately identify and return to the previously selected position, using a cam lever and slider to transition between home and memory positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a memory mechanism is operatively coupled to the movable track to define previously selected positions, then the seat assembly can return to previously selected positions, but friction between the memory mechanism and movable track increases making operation difficult

Engineering Contradiction:
Improveposition retention accuracyVSAvoidoperational efficiency
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A cam lever is introduced as an intermediary component between the movable track and the memory plate. The cam lever converts the sliding motion of the movable track into rotational motion of the memory plate, reducing direct friction between the memory mechanism and movable track while maintaining position retention accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cam lever utilizes curved surfaces and rotational motion to transform linear sliding movement into rotational movement. This curvature-based mechanism reduces friction by replacing sliding contact with rolling or pivoting contact, improving operational efficiency while preserving position memory functionality.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If the memory mechanism engages with the fixed track to define previously selected positions, then position memory is achieved, but imprecise engagement makes it difficult to return accurately to the selected position

Engineering Contradiction:
Improveposition retention accuracyVSAvoidposition return precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces direct linear engagement between the memory plate and fixed track with a cam lever mechanism that uses rotational motion and curved surfaces. This substitution improves positioning precision by allowing more controlled and accurate engagement through the cam profile geometry.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cam lever's curved surface enables precise angular positioning of the memory plate, which translates to precise linear positioning of the movable track. The geometric relationship between the cam profile and lever arm provides mechanical advantage for accurate position reproduction.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 enhances the smooth sliding movement and precise positioning of the seat assembly by reducing friction and ensuring accurate return to the selected position, improving the overall operational efficiency and ease of use.

Implementation Method 1

roller bearings

Methodology Applied
Scientific EffectFriction reduction: Roller

Implementation Method 2

a spring positioned adjacent the memory plate and adapted to exert a force on the memory plate

Methodology Applied
Scientific EffectElastic force: Spring

Implementation Method 3

a cam lever and slider operable in response to pivoting the seat back

Methodology Applied
Scientific EffectMechanical advantage: Cam

Data Source

PatentEP3962773B1Seat track assembly with memory mechanism
Publication Date: 2025.01.01 MAGNA SEATING INC
  • EP3962773B1 patent drawingFigure 1
  • EP3962773B1 patent drawingFigure 2
  • EP3962773B1 patent drawingFigure 3

AI summary

A seat track assembly provides forward and rearward movement of a seat assembly. A latch mechanism allows movement of a movable track between a plurality of positions. A memory mechanism with a memory plate and a memory tab are operable between a home position in which the memory tab is disposed in a recess of the moveable track, and a memory position in which the memory plate is coupled with a plurality of angled teeth to define a selected position. Actuation of the memory mechanism to the memory position unlocks the latch mechanism to allow movement of the movable track in a first direction away from the selected position to an easy-entry position. Movement of the movable track in a second direction from the easy-entry position stops the movable track at the selected position, allowing the latch mechanism to lock and the memory mechanism to return to the home position.