Cable-Driven Lumbar Support Assembly for Lightweight Seat Frames

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Solution Overview

Problem

Existing lumbar support assemblies for vehicles face challenges in reducing weight while maintaining manufacturing convenience and durability, particularly in the context of electric vehicle fuel efficiency requirements.

Innovation Solution

A lumbar support assembly featuring a mat formed by interconnected wires, a tension unit with cables, and a drive unit integrated with the seat frame, utilizing injection molding for weight reduction and improved manufacturing efficiency, eliminating the need for springs and enhancing durability through sealing members and multi-step hook mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If traditional lumbar support assembly structures are used, then structural strength and durability are maintained, but weight increases and fuel efficiency decreases

Engineering Contradiction:
Improveweight of lumbar support assemblyVSAvoidstructural strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent replaces traditional rigid metal spring structures with flexible cable elements that provide the necessary support function while significantly reducing weight. The cables act as flexible load-bearing elements that maintain structural integrity without the mass of conventional metal components.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the material parameters from dense metal springs to lighter cable materials, transforming the physical state and density of the load-bearing components. This parameter change enables weight reduction while maintaining the mechanical support function through proper cable tension and routing design.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If weight reduction measures are implemented, then fuel efficiency improves, but manufacturing complexity increases

Engineering Contradiction:
Improveweight of lumbar support assemblyVSAvoidmanufacturing convenience
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The lumbar support assembly is divided into modular components: the mat with wirenet, the separate cable tension unit, and the drive unit. This segmentation allows each component to be manufactured independently using optimized processes, then assembled together, simplifying overall manufacturing while enabling weight reduction in each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces complex mechanical spring systems with a cable-pulley mechanism driven by an actuator. This substitution simplifies the manufacturing process by using standard cable and pulley components rather than custom-formed metal springs, reducing manufacturing complexity despite the weight reduction goal.

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

3Ease of manufacture

If simple connection structures are used, then manufacturing cost decreases, but durability and reliability are compromised

Engineering Contradiction:
Improvemanufacturing costVSAvoiddurability of connection
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent merges the cable attachment points with the mat structure itself, integrating the connection function into the existing components rather than adding separate fasteners or joints. This merging reduces the number of parts and assembly steps while maintaining reliable connections through direct integration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cables are pre-tensioned and pre-positioned during assembly to ensure proper load distribution and connection integrity from the start. This preliminary action ensures that the simple connection structures are immediately reliable upon installation, eliminating the need for complex adjustment mechanisms or multiple assembly steps.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4122757B1Lumbar support assembly
Publication Date: 2024.04.17 DAE CHANG SEAT CO LTD DONGTAN
  • EP4122757B1 patent drawingFigure 1
  • EP4122757B1 patent drawingFigure 2
  • EP4122757B1 patent drawingFigure 3

AI summary

Proposed is a lumbar support assembly including a mat formed by connecting wires in such a manner as to take shape in the form of a net and connected to a seat frame in such a manner as to be rotatable forward or backward, a tension unit comprising first and second cables, respective first end portions of the first and second cable being connected to opposite sides, respectively, of the seat frame, and respective second end portions thereof extending to the mat, and a drive unit mounted under a center portion of the mat and connected to the respective second end portions of the first and second end portions, the drive unit being configured to pull or release the first and second cables.