Plastic-Molded Rotary Encoder With Threaded Motion Conversion

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Solution Overview

Problem

Existing rotary encoders are complex, costly, and prone to wear due to the need for sensitive sensor components and specially adapted precision parts, making them unsuitable for harsh environments and multiple revolutions.

Innovation Solution

A rotary encoder design featuring plastic molded parts with integrated threads for mechanical conversion of rotary motion into linear translation, using a gear-like arrangement with a contactless distance sensor, reducing component complexity and enhancing robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional rotary encoders use sensitive sensor components and specially adapted precision parts, then measurement precision is improved, but device complexity increases and manufacturing cost increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidcomponent complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical sensor components with a gear-like arrangement consisting of a screw element and a nut element, where the mechanical conversion of rotary motion to linear motion is achieved through threaded engagement. This substitution eliminates the need for sensitive optical or magnetic sensors while maintaining measurement capability through direct mechanical coupling.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The gear-like arrangement uses the inherent mechanical properties of threaded fasteners to perform both the conversion function and the measurement function. The linear displacement of the nut element relative to the screw element directly provides the measurement signal, eliminating the need for separate sensing mechanisms and reducing overall device complexity.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If traditional rotary encoders use specially adapted precision parts, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent combines the functions of motion conversion and measurement into a single integrated gear-like arrangement. The screw element and nut element work together to both convert rotary motion to linear motion and provide the measurement signal simultaneously, reducing the number of separate precision components needed and lowering manufacturing costs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention changes the fundamental operating parameters from traditional encoder schemes to a mechanical threaded engagement system. By using standard threaded fastener geometries with well-defined pitch and lead, the system achieves precise measurement through mechanical parameters rather than requiring expensive specialized components.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If traditional rotary encoders use sensitive sensor components, then measurement precision is improved, but reliability decreases due to wear and environmental sensitivity

Engineering Contradiction:
Improvedetection accuracyVSAvoidrobustness against wear and environmental influences
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces sensitive electronic or optical sensor components with a robust mechanical threaded engagement system. The screw and nut elements provide direct mechanical coupling that is inherently more resistant to environmental influences such as dust, moisture, and electromagnetic interference, while maintaining measurement precision through the defined mechanical relationship.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The gear-like arrangement provides inherent mechanical protection through the enclosed threaded engagement. The screw element and nut element form a protected mechanical interface that cushions against environmental attacks and reduces wear through the self-lubricating properties of threaded fasteners, enhancing reliability before failures can occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 design ensures accurate detection of rotary motion with reduced components, enabling cost-effective, robust, and simple manufacturing, suitable for multiple rotations and harsh conditions.

Implementation Method 1

the gear-like arrangement has a first thread on the first component (101), which cooperates with a second thread on the distance sensor and/or on the second component (102) for the mechanical conversion of a rotary movement into a linear translation movement

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP4511618B1Rotary encoder
Publication Date: 2025.10.08 IGUS SE & CO KG
  • EP4511618B1 patent drawingFigure 1A~1B
  • EP4511618B1 patent drawingFigure 2A~2B
  • EP4511618B1 patent drawingFigure 3

AI summary

The invention relates to a rotary encoder (100, 200, 304) for rotational movement detection, in particular for repeated revolutions, comprising a gear-like arrangement having a first component (101, 201) and a second component (102, 202) for mechanically converting a rotational movement into a linear translational movement that changes an axial relative position between the two components (101, 201, 102, 202), and a distance sensor (103, 203) for determining a distance from a measurement object (104, 204) that is dependent on the axial relative position. According to the invention, the first component (101, 201) and the second component (102, 202) are produced as plastic moulded parts, in particular as injection-moulded parts, and the gear-like arrangement has, on the first component (101, 201), a first thread (1010, 2010) that interacts with a second thread (1020, 2020) on the distance sensor (103, 203) and/or on the second component (102, 202) to mechanically convert a rotational movement into a linear translational movement.