Vehicle Seatback Hub and Annular String Connection

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Solution Overview

Problem

Existing vehicle seat designs face issues with the detachment of strings from the connection member under excessive load and limited adjustability of the net's flexibility, which affects the occupant's comfort and safety during vehicle maneuvers.

Innovation Solution

The vehicle seat incorporates an annular string system with a hub member connected through a plurality of installation members, where the strings are wrapped around or threaded through pins or grooves without being fixed, providing resistance against loads and allowing for easy adjustment of the seat's hardness and stiffness by changing the string material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large hook is attached to one end of the string to enhance connection between the strings and the connection member, then the reliability of string connection is improved, but the device complexity increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an installation member as an intermediary component between the string and the hub member. The installation member includes a groove that receives and secures the string end, providing a reliable connection without requiring complex hooks. This intermediary structure simplifies the overall design while ensuring secure string attachment under load.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the net is designed to be flexible to allow occupant movement, then the ease of operation is improved, but the strength to resist excessive load deteriorates

Engineering Contradiction:
Improveoccupant movement flexibilityVSAvoidload resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent employs dynamic design where the net and strings can flex and deform under load to accommodate occupant movement, while the hub member and installation members provide dynamic load distribution. The system transitions from a rigid structure to a flexible yet strong configuration that adapts to varying load conditions, maintaining both flexibility and strength.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses composite construction combining flexible net material with stronger string and hub member components. The net provides flexibility for occupant movement, while the strings and hub member structure provide the necessary strength to resist excessive loads, creating a composite system that achieves both properties simultaneously.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the connection member serves as a rotational center to allow upper body sway, then the ease of operation is improved, but the stress concentration on the connection member increases

Engineering Contradiction:
Improveupper body sway freedomVSAvoidstress concentration
Core Design Contradiction:
Ease of operationVSStress or pressure

Solution Approach 1:

The patent segments the load-bearing function from the rotational center function. The hub member serves as the rotational center allowing upper body sway, while the installation members and strings segment the load path to distribute stress. This segmentation prevents stress concentration at the rotational center by directing forces through multiple load-bearing elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by providing different structural properties at different locations. The hub member has a groove with specific local geometry to receive the string end, creating a localized stress distribution pattern that reduces overall stress concentration. The installation member's groove geometry is specifically designed to locally manage stress while allowing rotational movement.

Inventive Principle:
Principle #3Local quality

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 prevents string detachment under significant loads, enhances the seat's durability, and allows for adjustable flexibility and comfort by distributing stress effectively, ensuring the occupant's safety and comfort during vehicle movements.

Implementation Method 1

the first portion wrapped around or threaded through the installation member

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a plurality of strings drawn radially between the hub member and the seatback frame to form a seatback supporting an upper body

Methodology Applied
Scientific EffectTension: Tension

Implementation Method 3

establish a resistance counteracting a load applied to the hub member

Methodology Applied
Scientific EffectForce distribution: Force

Implementation Method 4

the tensions of the annular strings and the tension string serve as a resistance against a lateral load applied to the hub member

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP3279032B1Vehicle seat with ergonomic seat-back
Publication Date: 2020.07.01 TOYOTA JIDOSHA KK
  • EP3279032B1 patent drawingFigure 1
  • EP3279032B1 patent drawingFigure 2
  • EP3279032B1 patent drawingFigure 3

AI summary

A vehicle seat with enhanced rigidity in which a property of a backrest can be adjusted easily is provided. In the vehicle seat (1), a hub member (10) is situated at a predetermined level of width center of the seatback frame (6), and annular strings (13) are drawn radially between the hub member (10) and the seatback frame (6). In the annular string (13), a first portion (13B) is wrapped around the installation member (15) of the hub member (10), a second portion (13C) is attached to the seatback frame (6), and a pair of straight portions (13A) is drawn between the first portion (13B) and the second portion (13C).