Universal Rolling Elements for Multi-Pitch Screw Drives

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Solution Overview

Problem

Existing screw drive devices require significant design effort and component variations to accommodate different pitches, leading to increased manufacturing costs and complexity.

Innovation Solution

A device design where rolling elements with specific groove offsets can be used across various screw drive variants, including single and multi-threaded spindles, by maintaining the same pitch circle diameter and allowing for symmetrical offset arrangements, reducing the need for multiple types of rolling elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different variants of screw drives are designed to accommodate different pitches, then the adaptability to different applications is improved, but the device complexity and design effort increase significantly

Engineering Contradiction:
Improveadaptability to different pitchesVSAvoiddesign effort and component variations
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The rolling elements are designed with a universal groove structure that can accommodate multiple thread pitches through symmetrical offset arrangements. The same rolling element design can be used for single-threaded, double-threaded, and multi-threaded spindles by adjusting the offset pattern, making the rolling elements multi-functional across different screw drive variants

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

Solution Approach 2:

Instead of changing the rolling element design for different pitches, the invention changes the offset parameter arrangement. By varying the offset distances and patterns of identical rolling elements, different thread pitches can be achieved with the same rolling element inventory, thus adapting to different applications without redesigning components

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If multiple types of rolling elements are designed for different screw drive variants, then the manufacturing precision for specific pitches is improved, but the quantity of different parts increases

Engineering Contradiction:
Improvepitch accuracyVSAvoidnumber of rolling element types
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

A single rolling element design serves multiple pitch requirements through different offset arrangements. The universal design maintains manufacturing precision for various pitches while reducing the quantity of different rolling element types to a minimum set that can be configured for different applications

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

Solution Approach 2:

The invention achieves different pitch accuracies by changing the offset parameters of identical rolling elements rather than manufacturing different rolling element types. This parameter-based adaptation reduces the number of unique parts while maintaining the required precision for each pitch variant

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If spindles with different numbers of gears are used to vary pitch, then the adaptability to different feed rates is improved, but the ease of manufacture deteriorates due to required design adaptation of other components

Engineering Contradiction:
Improvefeed rate variationVSAvoiddesign adaptation effort
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The rolling elements are designed to be universally compatible with spindles having different numbers of gears. The same rolling element inventory can be used with single-threaded, double-threaded, or multi-threaded spindles by adjusting the offset arrangements, eliminating the need to redesign rolling elements when changing spindle configurations

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

Solution Approach 2:

The invention separates the pitch determination function into two independent parts: the spindle geometry (number of gears) and the rolling element offset arrangement. This segmentation allows the rolling elements to remain unchanged while the spindle configuration varies, simplifying manufacturing by decoupling the design adaptation requirements

Inventive Principle:
Principle #1Segmentation

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 approach allows for the production of different screw drive variants with reduced design and manufacturing effort, using the same rolling elements across various configurations, thereby minimizing the number of parts and costs.

Implementation Method 1

one of which has an axial frictional connection with the external profile of the spindle and the other other creates an axial frictional connection with the nut

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

rolling elements arranged in between, which have different profiles... The rolling bodies, which are rotatably mounted in spacer disks at the ends, roll at a specific rotational speed

Methodology Applied
Scientific EffectRolling: Roller

Data Source

PatentEP1978283B1Method of assembling a device for transforming rotary motion into axial motion
Publication Date: 2012.06.13 NARR BETEILIGUNGS
  • EP1978283B1 patent drawingFigure 1
  • EP1978283B1 patent drawingFigure 2a~3
  • EP1978283B1 patent drawingFigure 4~5

AI summary

The device has a spindle (2), which includes an outer profile (3) in the form of thread. A nut (4) includes an inner profile (5) and surrounds the spindle. Rolling bodies (6) exhibit two different profiles, where one of the profiles produces an axial frictional connection for the outer profile of the spindle and the other profile produces an axial frictional connection for the inner profile of the nut. Different variants of thread impulse are formed by the utilization of the spindles. Same rolling bodies are used for all variants of thread impulse.