Single-Guide Electric Actuator for Misalignment-Stable Linear Motion

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Solution Overview

Problem

Conventional test machines with multiple guide paths for linear movement often become misaligned due to thermal expansion, wear, or shipment, leading to operational difficulties and reduced side load capacity.

Innovation Solution

An electric actuator design using a single guide rod with compliant flexures and anti-rotate bearings, along with magnetic coupling units and a secondary force generating device, to maintain linear movement and side load capacity while minimizing overconstraint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple guide paths are used for linear movement, then the actuator can provide structural support and guidance, but misalignment occurs due to thermal expansion, wear, or shipment

Engineering Contradiction:
Improvealignment stabilityVSAvoidguide path configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The guide path is segmented into a fixed guide portion and a movable guide portion that can independently adjust their positions. This segmentation allows each portion to accommodate thermal expansion and wear independently, preventing misalignment while maintaining the structural support of multiple guide paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide paths are made dynamic through the use of adjustable positioning mechanisms that allow the movable guide portion to adapt its position in real-time. This dynamic adjustment capability compensates for thermal expansion, wear, and shipment-induced misalignment, maintaining reliable operation without requiring perfect initial alignment.

Inventive Principle:
Principle #15Dynamics

2Force

If multiple guide paths are used, then structural support is provided, but side load capacity is reduced due to misalignment

Engineering Contradiction:
Improveside load capacityVSAvoidalignment stability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The adjustable positioning mechanism performs preliminary alignment adjustments before operation begins. By pre-positioning the movable guide portion to compensate for anticipated thermal expansion, wear, or shipment effects, the system maintains optimal side load capacity without requiring perfect initial alignment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the positional parameters of the guide paths through adjustable mechanisms. By varying the position of the movable guide portion, the system optimizes alignment to maintain maximum side load capacity under different operating conditions, effectively adapting to thermal expansion, wear, and shipment-induced changes.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If conventional guide systems are used, then linear movement is guided, but operational difficulties arise from misalignment

Engineering Contradiction:
Improveoperational smoothnessVSAvoidalignment stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system incorporates feedback mechanisms that monitor the alignment and position of the guide paths during operation. Based on this feedback, the adjustable positioning mechanism automatically corrects misalignment, ensuring smooth operation and preventing operational difficulties without requiring manual intervention or perfect initial setup.

Inventive Principle:
Principle #23Feedback

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 electric actuator achieves stable linear displacement and constant side load capacity by reducing misalignment issues and optimizing the guiding system, enhancing operational reliability and performance.

Implementation Method 1

a first and second magnetic coupling units, each including a stationary component and a moving component, the moving components being joined to the moving assembly

Methodology Applied
Scientific EffectMagnetic coupling: Magnetism

Implementation Method 2

interaction of magnetic fields, the moving assembly moving along an axis defined by a guide

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 3

a flexure joining the bearing surface to the bearing support, the flexure being compliant for moments about axes orthogonal to the guide and stiff for forces along the axes orthogonal to the guide

Methodology Applied
Scientific EffectFlexibility: Elasticity

Implementation Method 4

The secondary force generating device can be a spring such as a mechanical spring (compression, tension, etc)

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 5

the bore and driven member form a sealed chamber filled with a gas

Methodology Applied
Scientific EffectGas pressure: Pressure Gradient

Data Source

PatentEP4042136B1Electric actuator
Publication Date: 2024.06.05 MTS SYSTEMS CORPORATION
  • EP4042136B1 patent drawingFigure 1~3
  • EP4042136B1 patent drawingFigure 4~5
  • EP4042136B1 patent drawingFigure 6

AI summary

An electric actuator (20) includes a stationary support (21) and a guide system having a single stationary guide (28) joined to the stationary support (21) having an axis (27). The actuator (20) also includes a stationary assembly (24) secured to the stationary support (21). A moving assembly (26) is movable relative to the stationary support (21) on the guide (28), where the moving assembly (26) and the stationary assembly (24) provide at least two sets of interacting magnetic fields disposed about the guide (28) at equal angular intervals. A test specimen support (76) is joined to the moving assembly (26) and disposed on one side of the stationary support (21) so as to move along the axis (27) with movement of the moving assembly (26), the axis (27) extending through the test specimen support (76).