Linear Drive Coupling Structure for Pure Push Rod Motion

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Solution Overview

Problem

Existing linear drives require a high design effort to convert rotary movement into purely linear movement of a connecting rod, which is inefficient and costly.

Innovation Solution

A linear drive design featuring a screw drive with a nut connected to a push rod via a coupling means that is mounted in a torsion-proof manner within a guide tube with a polygonal inner wall, utilizing a ball screw drive and an anti-twist device to ensure the push rod performs a purely linear movement without rotation, allowing for precise positioning with minimal components and low structural complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional mechanisms are used to convert rotary motion to linear motion, then the conversion function is achieved, but the design effort and structural complexity increase significantly

Engineering Contradiction:
Improvedesign effortVSAvoidstructural complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The coupling means integrates multiple functions: it connects the nut to the push rod, provides anti-rotation guidance, and enables linear motion conversion. By merging these functions into a single component with a polygonal outer surface that engages with the guide tube, the design eliminates the need for separate anti-rotation devices and complex coupling mechanisms, significantly reducing design effort and structural complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coupling means serves multiple purposes simultaneously: it acts as a connector between the nut and push rod, provides rotational guidance through its polygonal outer surface engagement with the guide tube, and enables the conversion of rotary motion to linear motion. This multi-functionality reduces the overall number of components and simplifies the design

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

2Reliability

If multiple separate components are used for coupling and anti-rotation, then functional requirements are met, but the number of parts and manufacturing costs increase

Engineering Contradiction:
Improvefunctional requirementsVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The coupling means combines the coupling function and anti-rotation function into a single integrated component. The polygonal outer surface of the coupling means engages with the polygonal inner wall of the guide tube, providing both connection and rotational guidance. This eliminates the need for separate anti-rotation devices, keys, or multiple coupling elements, reducing the total number of parts while maintaining functional reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single coupling means component performs multiple functions: it connects the nut to the push rod, prevents rotation of the push rod through its polygonal engagement with the guide tube, and enables efficient force transmission. This multi-functionality reduces part quantity while ensuring reliable operation

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

3Ease of manufacture

If simple coupling means is used, then manufacturing costs are reduced, but the push rod may rotate instead of moving purely linearly

Engineering Contradiction:
Improvemanufacturing costsVSAvoidpurely linear movement
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The coupling means features a polygonal outer surface (e.g., hexagonal) that asymmetrically engages with the polygonal inner wall of the guide tube. This asymmetric geometric engagement prevents rotation of the push rod while maintaining a simple, cost-effective manufacturing process. The polygonal shape provides inherent anti-rotation capability without requiring complex mechanisms or precision machining

Inventive Principle:
Principle #4Asymmetry

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 enables reproducible and precise positioning movements with reduced component count and production costs, suitable for applications like valve adjustments in bottling plants, where it ensures quick, reliable, and cost-effective operation.

Implementation Method 1

The screw drive is advantageously designed as a ball screw drive

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3901490B1Linear drive
Publication Date: 2023.03.01 ELERO GMBH
  • EP3901490B1 patent drawingFigure 1
  • EP3901490B1 patent drawingFigure 2
  • EP3901490B1 patent drawingFigure 3

AI summary

The invention relates to a linear drive (1) with an electric drive and a threaded drive, wherein a rotary movement of the electric drive is converted into a linear movement of a push rod (5). The threaded drive has a nut (4) which is connected to the push rod (5) via a coupling means (6), and the push rod (5) is mounted in a guide tube (7) in a rotationally secure manner by means of the coupling means (6).