Vehicle Flap Spindle Drive with Oldham Coupling and Hysteresis Brake

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Solution Overview

Problem

Existing spindle drive assemblies for vehicle lids face a conflict between cost-effective manufacturability and high reliability, with issues of drive stiffening and unwanted noises due to axial offset and manufacturing tolerances.

Innovation Solution

A spindle drive assembly with an axis offset-compensating clutch and hysteresis brake, utilizing an Oldham clutch and integrated hysteresis brake components to simplify manufacturing and assembly, ensuring reliability and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional spindle drive assemblies are manufactured with standard tolerances, then manufacturing cost is reduced, but drive stiffness deteriorates and unwanted noises occur due to axis misalignment

Engineering Contradiction:
Improvemanufacturing costVSAvoiddrive stiffness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

A coupling device is introduced as an intermediary component between the spindle drive motor and the gearbox. This coupling compensates for axis misalignment caused by tolerance variations, thereby maintaining drive stiffness and eliminating noises while allowing standard manufacturing tolerances to be used.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a coupling to compensate for axis misalignment is added, then drive stiffness is maintained and noises are eliminated, but device complexity increases

Engineering Contradiction:
Improvedrive stiffnessVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The coupling device is integrated with the existing hysteresis brake components. The rotatable hysteresis brake component is attached to the drive motor-side coupling, and the stationary hysteresis brake component is attached to the gearbox housing. This merging reduces the number of separate components and simplifies the overall structure while maintaining the axis misalignment compensation function.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If hysteresis brake components are added to limit motor shaft speed, then reliability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvemotor shaft controlVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hysteresis brake components are merged with the coupling structure. The rotatable hysteresis brake component is attached to the drive motor-side coupling, and the stationary hysteresis brake component is attached to the gearbox housing. This integration allows the hysteresis brake function to be achieved without adding significant complexity to the overall device.

Inventive Principle:
Principle #5Merging (Combining)

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 enables the production of a reliable, compact, and cost-effective spindle drive assembly that eliminates drive stiffening and unwanted noises, meeting both manufacturability and reliability demands.

Implementation Method 1

A hysteresis brake is interposed between the spindle drive motor and the gearbox

Methodology Applied
Scientific EffectHysteresis: Hysteresis

Implementation Method 2

The hysteresis brake serves to limit the speed of the motor shaft and/or to lock the motor shaft in place

Methodology Applied
Scientific EffectHysteresis damping: Hysteresis

Implementation Method 3

A coupling to compensate for axis misalignment is interposed between the spindle drive motor and the gearbox

Methodology Applied
Scientific EffectMechanical coupling:

Data Source

PatentEP3717722B1Spindle drive assembly and vehicle flap with a spindle drive assembly
Publication Date: 2023.11.29 MINEBEA ACCESSSOLUTIONS DEUTSCHLAND GMBH
  • EP3717722B1 patent drawingFigure 1~2
  • EP3717722B1 patent drawingFigure 3
  • EP3717722B1 patent drawingFigure 4

AI summary

A spindle drive assembly for opening and/or closing a vehicle flap is described, with a spindle extending along a spindle drive axis (16), and a spindle drive motor (36) which is coupled to the spindle in terms of drive via a gearing (40) and the motor shaft (38) of which is arranged substantially coaxially with respect to the spindle drive axis (16), wherein an axial-offset-compensating clutch (68) and a hysteresis brake (82) are connected in terms of drive between the spindle drive motor (36) and the gearing (40). In addition, a vehicle flap with such a spindle drive assembly is presented.