Belt Buckle Linear Drive Spindle Column Guide

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Solution Overview

Problem

Existing seat belt buckle presenters face challenges in achieving high power density, noise reduction, and compact design while reliably absorbing crash forces, with previous designs often requiring significant installation space and using metal components that can't meet crash load specifications.

Innovation Solution

A linear drive system with an axially displaceable spindle nut supported by a metal spindle and column, featuring low-noise plastic toothing engagements and metal components for load absorption, along with a plastic spacer for noise decoupling, and a coaxial cavity design to reduce housing size and prevent bending stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal components are used for load absorption, then strength and reliability are improved, but noise emissions increase

Engineering Contradiction:
Improvecrash load absorptionVSAvoidnoise emissions
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

A plastic spacer element is introduced as an intermediary component between the metal spindle and the metal housing. This plastic element mediates the interaction between metal components, allowing the metal parts to maintain their load-bearing function while the plastic spacer absorbs and dampens noise vibrations, preventing metal-on-metal contact noise during operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spindle nut is constructed as a composite component with both plastic and metal elements. The plastic portion provides noise damping and smooth operation, while the metal reinforcement ensures sufficient strength for load absorption. This composite structure combines the advantages of both materials to simultaneously reduce noise and maintain mechanical strength.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If the spindle is supported by a column to eliminate bending stresses, then positioning precision is improved, but device complexity increases

Engineering Contradiction:
Improvelinear positioning precisionVSAvoidguide system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The column support and the spindle are merged into a single integrated component rather than separate parts. The column is formed as an integral part of the spindle structure, eliminating the need for separate mounting connections and reducing assembly complexity. This integration maintains the precision-guiding function while simplifying the overall device structure.

Inventive Principle:
Principle #5Merging (Combining)

3Object-generated harmful factors

If plastic components are used for low-noise operation, then noise emissions are reduced, but strength and reliability under crash loads decrease

Engineering Contradiction:
Improvenoise emissionsVSAvoidcrash load absorption
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The spindle nut is constructed as a composite component with both plastic and metal elements. The plastic portion provides noise damping and smooth operation, while the metal reinforcement ensures sufficient strength for load absorption. This composite structure combines the advantages of both materials to simultaneously reduce noise and maintain mechanical strength.

Inventive Principle:
Principle #40Composite materials

4Volume of stationary object

If the installation space is reduced for compact design, then vehicle space utilization is improved, but the ability to absorb crash forces is compromised

Engineering Contradiction:
Improveinstallation spaceVSAvoidcrash load absorption
Core Design Contradiction:
Volume of stationary objectVSStrength

Solution Approach 1:

The column support is nested within the spindle structure, with the column being received inside the hollow spindle body. This nesting arrangement allows the support column to be housed within the existing spindle volume, providing additional structural support and crash load absorption capability without increasing the external dimensions or installation space requirements of the device.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 solution achieves a compact, statically determined guide system that effectively absorbs crash forces, reduces noise, and maintains precise linear positioning, addressing the limitations of previous designs by decoupling the spindle from guide functions and using metal components for load absorption.

Implementation Method 1

In the event of a load, the spacer or the plastic thread is compressed axially

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

a screw mechanism, in particular a trapezoidal screw, for the axial displacement of the spindle nut (21)

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 3

a gear mechanism, in particular a plastic bevel gear (22), for the rotation of the spindle nut (21)

Methodology Applied
Scientific EffectGear mechanism: Gear

Data Source

PatentEP3093201B1Belt buckle attachment
Publication Date: 2018.03.14 OECHSLER AG
  • EP3093201B1 patent drawingFigure 1
  • EP3093201B1 patent drawingFigure 2

AI summary

In an electromechanical linear drive with a spindle (20) that can be axially displaced by a spindle nut (21) for a belt buckle presenter (11), noise-generating fluctuations in engagement in the compact reduction gear (22) between motor (23) and spindle (20) are avoided by absorbing bending stresses of the spindle (20) by a column (34) arranged parallel to the axis next to or in it, which runs through a precise, device-fixed longitudinal guide (35).