Vehicle Seat Gas Spring Thread Mounting for Play-Free Adjustment

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Solution Overview

Problem

The existing adjustment devices for vehicle seats, particularly those using gas springs, face challenges in achieving a play-free mounting between the gas spring and the bearing device, leading to instability and inefficiency in adjusting mechanisms.

Innovation Solution

The solution involves using an external thread on the bearing device to mount the gas spring's free end, with an internal thread on the gas spring, where one thread is designed to be more elastic than the other, allowing for defined deformation and play-free mounting by varying thread parameters such as pitch, diameter, flank height, and angle, and using a bearing bushing and collar screw with a bolt for secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a gas spring is mounted on a bearing device using conventional threaded connections, then the mounting is simple and secure, but bearing play occurs between the gas spring and bearing device leading to noises and vibrations

Engineering Contradiction:
Improveconnection stabilityVSAvoidnoise and vibration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the geometric parameters of the thread connection by providing different thread pitches on the gas spring and bearing device. This parameter difference creates a tolerance compensation effect that eliminates bearing play while maintaining a secure threaded connection, thereby reducing noise and vibration without compromising connection stability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If threads with different parameters are used to eliminate bearing play, then a play-free connection is achieved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveconnection stabilityVSAvoidthread parameter tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

Instead of requiring tight tolerances on identical threads, the patent deliberately uses different thread pitches as a design parameter. This approach converts a precision problem into a deliberate parameter difference that naturally compensates for manufacturing tolerances, making the system more robust to variations while achieving play-free connection.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs different materials (plastic and metal) for the threading components. This material combination provides differential elasticity that complements the different thread pitches, allowing the softer plastic thread to deform and accommodate tolerance variations while the metal thread provides structural support, thereby reducing manufacturing precision requirements.

Inventive Principle:
Principle #40Composite materials

3Reliability

If threads with different parameters are used to accommodate tolerance variations, then play-free mounting is achieved, but device complexity increases

Engineering Contradiction:
Improveconnection stabilityVSAvoidthread configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a play-free connection by simply changing the thread pitch parameter between two standard threaded components. This is achieved through conventional manufacturing processes without adding extra parts, assemblies, or complex mechanisms. The different thread pitches are integrated into the basic threading design, maintaining simplicity while eliminating bearing play.

Inventive Principle:
Principle #35Parameter changes

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 approach enables a play-free connection between movable parts of a vehicle seat, ensuring stable and efficient adjustment by compensating for tolerance and achieving secure attachment through elastic deformation of the threads.

Implementation Method 1

At least one of the two threads is preferably designed to be more elastic than the other thread, so that the corresponding thread yields or is deformed in a defined manner when the two threads are screwed together

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2718143A1Adjusting device, in particular for a vehicle seat
Publication Date: 2014.04.16 MERCEDES BENZ GROUP AG

AI summary

The invention relates to an adjusting device (1) for adjusting a first part (2) relative to a second part (3), comprising a gas spring (10), which is designed and provided to connect the two parts (2, 3) to one another, a first free end (101) of the gas spring (10), and a bearing device (40), which is designed and provided to be fastened to the first part (2) or the second part (3), wherein the first free end (101) of the gas spring (10) is supported on the bearing device (40). According to the invention, the first free end (101) is supported on an external thread (A) formed on the bearing device (40) by means of an internal thread (I) formed on the first free end (101).