Vehicle Seat Backrest Head Adjustment with Elastic Impact Element

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Solution Overview

Problem

Conventional vehicle seats lack the ability to adapt the backrest structure to the individual body of the occupant, resulting in a fixed distance between the head panel and upper backrest surface, which does not accommodate varying user positions effectively and fails to adequately absorb impact forces during collisions.

Innovation Solution

A backrest head adjustment device with axially symmetrically arranged movable surface elements and an integrated elastic wire mat impact element, allowing for stepless adjustment in the direction of travel, which can be mechanically, electromechanically, or pneumatically actuated, to bring the surface elements closer to the occupant's shoulder and upper back area, forming a support surface that absorbs impact forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed backrest structure is used, then the structure is simple and stable, but it cannot adapt to individual body differences and fails to absorb impact forces

Engineering Contradiction:
Improveadaptability to individual bodyVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The backrest incorporates movable surface elements that can dynamically adjust their position along the longitudinal axis to adapt to different occupant body sizes and shapes. The surface elements are guided by profile grooves in the backrest frame, allowing them to move freely in the longitudinal direction while maintaining lateral stability. This dynamic configuration enables the backrest to conform to individual body differences without requiring a completely reconfigurable structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The backrest is divided into multiple independent surface elements (first, second, third surface elements) that can move and adjust independently within their respective profile grooves. Each surface element can be positioned separately to accommodate different body contours, allowing localized adaptation without moving the entire backrest structure. This segmentation provides adaptability while keeping each individual component relatively simple.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the head panel and upper backrest surface are positioned at a fixed distance, then the structure is stable, but it does not accommodate varying user positions effectively

Engineering Contradiction:
Improvecomfort for varying user positionsVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The surface elements are designed to be movable along the longitudinal axis of the backrest frame through profile grooves, allowing the distance between the head panel and upper backrest surface to be dynamically adjusted. This movement enables the backrest to accommodate varying user positions and body types without requiring complex active adjustment mechanisms, as the surface elements can passively adapt to different occupant dimensions.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a rigid backrest structure is used, then it provides stable support, but it cannot effectively decelerate the head and upper body during impacts

Engineering Contradiction:
Improveimpact absorption capabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The backrest incorporates an elastic impact element that changes its mechanical properties during impact events. Under normal conditions, the impact element remains compressed within its housing, providing minimal resistance. During a rear-end collision, the impact force causes the impact element to expand rapidly, increasing its stiffness and providing deceleration force to the occupant's head and upper body. This parameter change allows the structure to provide both comfort during normal use and protection during impacts without requiring a completely different structural design.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The elastic impact element is pre-compressed within its housing during normal operation, storing elastic potential energy. This beforehand cushioning prepares the system to rapidly deploy protective forces during impact events. The pre-compressed state allows the impact element to expand quickly when needed, providing immediate deceleration force without requiring complex active control systems or heavy structural reinforcement.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Adaptability or versatility

If movable surface elements are added to enable adjustment, then adaptability improves, but the device complexity increases

Engineering Contradiction:
Improvestepless adjustment capabilityVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The surface elements are designed to move freely along predetermined paths defined by profile grooves in the backrest frame. This guided movement provides stepless adjustment capability without requiring motors, actuators, or control systems. The surface elements can be positioned at any location along the longitudinal axis by simple manual manipulation or passive movement, achieving high adaptability with minimal additional components.

Inventive Principle:
Principle #15Dynamics

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 solution enables a more ergonomic fit, reducing the distance between the shoulder and upper backrest area, and effectively decelerates the head and upper body during impacts by allowing the neck and upper back to plunge into the impact area, thereby reducing whiplash effects and enhancing safety and comfort.

Implementation Method 1

at least one elastic impact element integrated into the at least one surface element... the elastic impact element is designed as a wire mat... which can be brought up to a neck and an upper back surface of a back part of a seated person by continuously adjusting the two movable surface elements in the direction of travel

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3655286B1Backrest part of a vehicle seat with an adjustment device of an upper backrest region
Publication Date: 2022.01.12 VOLKSWAGEN AG
  • EP3655286B1 patent drawingFigure 1~2
  • EP3655286B1 patent drawingFigure 3~4

AI summary

The invention relates to a backrest part (10) for a vehicle seat having a rest frame (1) in which a headrest adjustment device (2) is arranged, which enables a continuous adjustment in the upper region of the backrest part (10). The headrest adjustment device (2) comprises at least one surface element (2A) mounted movably in the rest frame (1) and at least one resilient impact element (2D) integrated in the at least one surface element (2A), which are arranged to as to be jointly adjustable relative to the head part (1B) of the rest frame (1) counter to and in a direction of travel (+/-x direction).