Vehicle Seat Base Frame Single Actuator Height Adjustment

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Solution Overview

Problem

Existing motor vehicle seat subframes require multiple actuators and components for height adjustment, increasing complexity and occupying valuable space, while aiming to minimize components and maintain low overall height with efficient drive mechanisms.

Innovation Solution

A single actuator is positioned diagonally within a four-bar linkage underframe, utilizing a spindle drive with a geared motor and spindle nut, where the other side of the seat is passively adjusted, reducing component count and using common drive components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple actuators and components are provided for height adjustment on both sides of the seat, then adjustment reliability is improved, but device complexity increases and valuable space is occupied

Engineering Contradiction:
Improveadjustment reliabilityVSAvoidcomponent count
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the height adjustment function for both sides of the seat into a single actuator (13) positioned diagonally within the four-bar linkage structure. This single actuator controls the height adjustment for the entire seat base, eliminating the need for separate actuators on each side and reducing overall component count while maintaining adjustment reliability through the mechanical advantage of the four-bar linkage mechanism

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single actuator (13) serves a universal function by controlling the height adjustment for both the left and right sides of the seat simultaneously. The diagonal positioning within the four-bar linkage allows this single component to influence the entire seat structure, making the actuator multi-functional rather than requiring dedicated actuators for each side

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple actuators and components are provided for height adjustment, then adjustment functionality is improved, but the overall height of the subframe increases

Engineering Contradiction:
Improveadjustment functionalityVSAvoidsubframe height
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The actuator (13) is nested diagonally within the existing four-bar linkage structure of the subframe. This diagonal integration allows the actuator to be housed within the structural envelope rather than adding external height, as the actuator utilizes the internal space of the linkage mechanism already present in the subframe design

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If a single actuator is provided for height adjustment, then device complexity is reduced and space is optimized, but adjustment reliability may be compromised

Engineering Contradiction:
Improvecomponent countVSAvoidadjustment reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The actuator (13) is positioned asymmetrically diagonally within the four-bar linkage, closer to one side of the seat than the other. This asymmetric positioning creates an mechanical advantage where the actuator's linear motion is translated through the linkage to produce synchronized height adjustment across both sides of the seat, maintaining reliability through the geometric constraints of the asymmetric four-bar mechanism

Inventive Principle:
Principle #4Asymmetry

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 configuration allows for efficient height adjustment with minimal components, optimizing space and maintaining a low profile, while ensuring reliable locking and reduced complexity in the subframe design.

Implementation Method 1

a spindle drive, as is widely known from the prior art, is preferably used for the actuating drive

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP2337704B1Base frame of a vehicle seat comprising two pairs of rails, rockers and one seat support
Publication Date: 2014.03.26 JOHNSON CONTROLS METALS & MECHANISMS GMBH & CO
  • EP2337704B1 patent drawingFigure 1~2

AI summary

The base frame of a vehicle seat has two rail pairs (20, 22), two forward rockers (32), two rear rockers (34) and one seat support comprising two side parts (24, 26), one forward traverse (28) and one rear traverse (30). Each rail pair is hinged to a side part by way of a forward rocker (32) and a rear rocker (34). A positional drive (36) is provided for height adjustment of the seat support. A rocker is connected to a cross member (42). A support part (46) is provided which is connected to the cross member (42) and which comprises a hinge area (48) for an adjustment part of the positional drive and a hinge area (50) at the adjacent traverse.