Vehicle Seat Headrest Composite Drive for Longer Stroke

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Solution Overview

Problem

Existing headrest mechanisms in vehicle seats, particularly for zero-gravity seats, suffer from insufficient stroke, large space occupation, and compromised appearance due to exposed parts.

Innovation Solution

A composite motion mechanism combining a screw-nut mechanism and a pinion-rack mechanism is employed to enhance the stroke of the headrest, while minimizing space occupation and maintaining a sleek appearance by integrating components within the headrest.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a headrest cover is made from a single piece of material, then manufacturing is simple and cost-effective, but the cover cannot be selectively removed or replaced without removing the entire cover

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidselective removal capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The headrest cover is divided into multiple separable portions: a first headrest cover portion and a second headrest cover portion. These portions can be selectively removed and replaced independently, allowing users to change only specific sections of the cover rather than the entire cover. This segmentation enables selective removal while maintaining manufacturing simplicity through modular construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The separable cover portions are designed to nest together or attach to the headrest structure in a hierarchical manner. The first and second portions can be independently attached and detached from the headrest, allowing selective replacement while maintaining the overall cover assembly. This nesting approach enables versatility without requiring complete disassembly.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If a headrest cover is designed to be fully removable and replaceable, then adaptability and comfort customization are improved, but the structural complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvecover replacement capabilityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of designing a completely complex fully-removable system, the cover is segmented into portions that can be selectively removed. This reduces structural complexity compared to a fully disassemblable cover while still providing adaptability and replacement capability for individual sections.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The headrest cover system incorporates dynamic attachment and detachment capabilities through separable portions. The first and second cover portions can be dynamically attached or removed based on user needs, providing adaptability without requiring the entire cover structure to be complex and fully disassemblable.

Inventive Principle:
Principle #15Dynamics

3Reliability

If headrest covers are made from non-porous materials, then durability and ease of cleaning are improved, but breathability and comfort are reduced

Engineering Contradiction:
ImprovedurabilityVSAvoidbreathability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The headrest cover portions are made from porous materials that provide both breathability and durability. The porous structure allows air permeability for comfort while maintaining the material's strength and ease of cleaning. This resolves the contradiction by using materials that inherently possess both desired properties rather than choosing between non-porous durability or porous breathability.

Inventive Principle:
Principle #31Porous materials

Data Source

PatentEP4375138B1Seat headrest and vehicle seat
Publication Date: 2026.05.06 YANFENG INTERNATIONAL AUTOMOTIVE TECHNOLOGY CO LTD
  • EP4375138B1 patent drawingFigure 1~5
  • EP4375138B1 patent drawingFigure 6~8
  • EP4375138B1 patent drawingFigure 9~10

AI summary

The present invention relates to a seat headrest device comprising a fixed base (30), a headrest (20) and a headrest electric motor (40). The headrest electric motor (40) drives the headrest (20) to move relative to the fixed base (30) through a composite motion mechanism comprising a screw-nut mechanism (70) and a pinion-rack mechanism (10). The present invention further discloses a seat headrest device comprising the seat headrest device. The seat headrest device has the following characteristics: a stroke of the headrest can be significantly enhanced by means of the composite movement mechanism.