Active Scissor Seat Suspension Without Damper End Stops

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Solution Overview

Problem

Conventional vehicle seat suspension systems with scissor frames and dampers are limited by finite stroke length and risk of end stop, leading to overshoot movements and inadequate vibration damping due to high spring rates and inertial forces.

Innovation Solution

An active vehicle seat suspension system using a scissor frame with a motor-driven gear belt to control scissor arm position and height distance between the upper and lower parts, eliminating the need for a damper by actively adjusting the scissor arm position through a toothed belt and motor, which reduces overshoot and stabilizes the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a damper with finite stroke length is used to dampen vibrations, then vibration damping is achieved, but the system risks reaching end stop and causing overshoot movements

Engineering Contradiction:
Improvevibration damping capabilityVSAvoidovershoot movements
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies active dynamic control by replacing the passive damper with a motor-driven scissor arm system. The motor actively adjusts the scissor arm position in real-time to counteract vibrations, eliminating the finite stroke limitation and preventing overshoot movements through continuous positional control rather than fixed mechanical damping.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent substitutes the mechanical damper system with an electromechanical system consisting of a motor, gear belt, and scissor arm mechanism. This replacement transitions from passive mechanical damping to active electromagnetic control, enabling precise positioning without end-stop limitations and eliminating overshoot through controlled motor operation.

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

2Strength

If high spring rates are used throughout the vibration range, then system stiffness is maintained, but natural frequency increases and overshoot is exacerbated

Engineering Contradiction:
Improvesystem stiffnessVSAvoidovershoot control
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent implements dynamic stiffness control where the motor actively manages the scissor arm position to provide the necessary stiffness support without relying on high spring rates. This active control allows the system to maintain stability and counteract vibrations through controlled motor torque rather than mechanical spring force, reducing natural frequency and preventing overshoot.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a motor-driven gear belt system is used to control scissor arm position, then overshoot is eliminated and vibration damping is improved, but device complexity increases

Engineering Contradiction:
Improveovershoot eliminationVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent achieves multi-functionality by designing the motor-driven scissor arm system to simultaneously perform vibration damping, position control, and overshoot prevention. The single motor-gear belt assembly replaces what would traditionally require separate dampers, springs, and control mechanisms, reducing overall system complexity while achieving superior performance.

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

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

The system effectively dampens vibrations without inertial forces and eliminates overshoot, achieving a near-zero spring rate and reduced frictional forces, allowing for precise control and cushioning of vertical movements without end stops.

Implementation Method 1

The motor, which acts and can act by means of its rotational force and torque against a movement of the vehicle seat suspension system

Methodology Applied
Scientific EffectTorque: Torque

Implementation Method 2

such a motor has to overcome lower frictional forces due to its overall design

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4464550A1Active vehicle seat suspension system
Publication Date: 2024.11.20 GRAMMER AG
  • EP4464550A1 patent drawingFigure 1~2
  • EP4464550A1 patent drawingFigure 3~4
  • EP4464550A1 patent drawing

AI summary

The invention relates to an active vehicle seat suspension system comprising a lower part (4) and an upper part (3) of a vehicle seat (1) and a scissor frame arranged between them, with at least one first and at least one second scissor arm (5, 6) pivotally connected thereto, wherein at least the first scissor arm (6) is pivotally connected to the upper part (3) at a first end (6a) and pivotally connected to the lower part (4) at a second end (6b) and is displaceable thereon, wherein at least one traction element (16) movable forwards or backwards in the longitudinal direction (9) of the second end (6b) of the first scissor arm (6) is rigidly connected to at least one rolling axle (15) arranged at the second end (6b).