Ball Screw Return Tube Retention With Pin-Fixed Nut Structure

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Solution Overview

Problem

The existing ball screw devices require a metal plate attachment component and a bolt for retaining the return tube, increasing the number of components and necessitating a threaded hole on the nut, as well as a screw tightening process during assembly.

Innovation Solution

The ball screw device employs pin components radially positioned outside the leg parts to suppress displacement of the circulation component, eliminating the need for a metal plate and bolt, and omitting the requirement for a threaded hole on the nut, thereby simplifying the configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal plate attachment component and bolt are used to retain the return tube, then the circulation component is securely retained, but the number of components increases and the assembly process becomes more complex

Engineering Contradiction:
Improveretention of circulation componentVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the retention function directly into the nut structure by forming through holes through the nut body, eliminating the need for separate attachment components and bolts. The circulation component is retained through the structural integration of the nut and through holes, reducing the total number of components while maintaining secure retention.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent removes the metal plate attachment component and bolt from the assembly, extracting only the essential retention function and implementing it through the nut's through hole structure. This extraction simplifies the overall device by eliminating unnecessary components.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a metal plate attachment component and bolt are used to retain the return tube, then the circulation component is securely retained, but the assembly process requires additional steps

Engineering Contradiction:
Improveretention of circulation componentVSAvoidassembly process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The retention function is merged into the nut structure itself through the through holes, eliminating the need for separate attachment components and bolts. This integration simplifies the assembly process by reducing the number of steps required to secure the circulation component.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a threaded hole is formed on the nut for bolt fastening, then the circulation component can be retained, but the manufacturing complexity increases

Engineering Contradiction:
Improveretention of circulation componentVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent removes the threaded hole and bolt fastening system, extracting only the essential retention function and implementing it through simple through holes in the nut. This extraction reduces manufacturing complexity by eliminating the need for threading operations and bolt installation.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3889466B1Ball screw device
Publication Date: 2024.05.01 NSK LTD
  • EP3889466B1 patent drawingFigure 1
  • EP3889466B1 patent drawingFigure 2
  • EP3889466B1 patent drawingFigure 3

AI summary

A ball screw device includes: a screw shaft the outer peripheral surface of which has a first thread groove; a nut the inner peripheral surface of which is provided with a second thread groove that matches the first thread groove, and the outer peripheral surface of which is provided with a through hole; a plurality of balls that roll between the first thread groove and the second thread groove; a circulation component including a main body part and a pair of leg parts provided on both ends of the main body part, and that is provided on the nut; and a pin component that fixes the circulation component to the nut. Each of the leg parts is inserted into the through hole, the pin component is provided on the leg part in an overlapping manner, and the leg part is retained in the through hole by the pin component.