Claw-Coupled Spindle Drive for Compact Thermal Compensation

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Solution Overview

Problem

Existing linear drives are not compact enough and require separate enclosures for components, leading to inefficiencies and increased part counts.

Innovation Solution

A spindle drive system where an electric motor is connected to a threaded spindle via a claw clutch, with a centering seat on the rotor shaft to integrate the clutch and reduce part count, utilizing a fixed bearing and an intermediate part made of elastic material for thermal compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a separate housing is used for the motor and spindle drive, then component protection and ease of assembly are improved, but device volume and part count increase

Engineering Contradiction:
Improveease of assemblyVSAvoiddevice volume
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The motor housing and spindle drive housing are merged into a single integrated housing structure. The motor rotor shaft extends directly through the housing to connect to the threaded spindle, eliminating the need for separate housings and reducing overall device volume while maintaining assembly simplicity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single housing serves multiple functions: it houses the motor, supports the rotor shaft bearing, protects the threaded spindle, and provides structural support for the entire assembly. This multi-functional design reduces part count while improving manufacturing efficiency.

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

2Strength

If a rigid coupling is used between motor and spindle, then mechanical rigidity is improved, but thermal compensation capability deteriorates

Engineering Contradiction:
Improvemechanical rigidityVSAvoidthermal compensation capability
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The coupling material's thermal expansion parameter is changed by selecting a material with thermal expansion coefficient matching both the motor rotor shaft and threaded spindle. This allows the coupling to expand and contract with temperature changes while maintaining mechanical rigidity and proper alignment.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If precision centering is achieved through multiple separate components, then centering accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvecentering accuracyVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The centering functions are merged into the coupling component itself. The coupling's precisely machined bore provides the centering seat for the rotor shaft, and its outer diameter provides the centering surface for the threaded spindle, achieving high centering accuracy in a single component rather than through multiple separate alignment features.

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

This design results in a compact, integrated drive with reduced heat loss and fewer parts, allowing for precise centering and thermal compensation, while maintaining mechanical rigidity and adaptability for various drive variants.

Implementation Method 1

the coupling compensates for thermal expansion and contraction of the rotor shaft and threaded spindle

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3224932B1Linear drive, having a spindle drive which can be driven by an electric motor via a clutch
Publication Date: 2024.09.04 SEW EURODRIVE GMBH & CO KG
  • EP3224932B1 patent drawingFigure 1
  • EP3224932B1 patent drawingFigure 2
  • EP3224932B1 patent drawingFigure 3

AI summary

Linear drive, having a spindle drive which can be driven by an electric motor via a clutch, wherein the electric motor has a rotor shaft which is rotatably mounted by means of a bearing, wherein the spindle drive has a threaded spindle which is connected, in particular in a rotationally secured manner, to the rotor shaft by means of the clutch, wherein a clutch part of the clutch is connected in a rotationally secured manner to the threaded spindle and has claw sections, there being formed, on the rotor shaft, claw sections which are in engagement, via an interposed intermediate part, with the claw sections of the clutch part.