Monobloc Ball Screw Recirculator for Undercut-Free Molding

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Solution Overview

Problem

Existing ball screw mechanisms with recirculators have complex geometries that make manufacturing difficult due to counter-deputies and superposition issues.

Innovation Solution

A monobloc recirculation piece with a background, recirculation path, deflectors, and lights that allow for axial molding without counter-deputies, reducing material usage and simplifying manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a one-piece recirculation part is designed with deflectors and guide faces to guide balls along an S-shaped path, then ball guidance effectiveness is improved, but the part geometry becomes complex with undercuts making molding difficult

Engineering Contradiction:
Improveball guidance effectivenessVSAvoidmolding complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces lights that extend in the axial direction (perpendicular to the reference plane) to create openings through the recirculation part. This dimensional approach allows the guide faces to be molded without undercuts by providing escape paths for the molding material, effectively resolving the conflict between complex geometry and manufacturability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The recirculation part is segmented into functional zones: deflectors for guiding balls, guide faces for precise positioning, and lights for manufacturing accessibility. This segmentation allows each element to be optimized independently while maintaining overall functionality.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the recirculation part is made as a single integrated piece with all functional elements, then assembly is simplified, but manufacturing complexity increases due to multiple undercuts

Engineering Contradiction:
Improvenumber of partsVSAvoidmolding process complexity
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

By extending lights in the axial dimension, the patent enables the molding of an integrated recirculation part without undercuts. The lights create through-openings that allow molding material to escape and facilitate demolding, making single-piece manufacturing feasible despite the complex functional geometry.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If the guide face is positioned close to the recirculation path to effectively guide balls, then ball guidance precision is improved, but the deflector overlaps with the recirculation path body making molding impossible

Engineering Contradiction:
Improveball guidance precisionVSAvoidmolding feasibility
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent resolves the overlap conflict by introducing lights that extend in the axial direction through the recirculation path body. This creates openings that eliminate the undercut problem while allowing the guide face to remain positioned close to the recirculation path for effective ball guidance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Strength

If the recirculation part uses more material to maintain structural integrity and guide face support, then mechanical strength is improved, but material consumption and manufacturing complexity increase

Engineering Contradiction:
Improvestructural integrityVSAvoidmaterial consumption
Core Design Contradiction:
StrengthVSLoss of substance

Solution Approach 1:

The patent employs a thin-walled recirculation part structure with strategically placed lights for structural reinforcement. The lights act as both manufacturing features and structural elements that maintain integrity while minimizing material usage. The guide faces and deflectors are positioned to provide maximum guidance effectiveness with minimal material.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP4553344A1Recirculation monoblock, recirculating threaded member and ball screw mechanism
Publication Date: 2025.05.14 NTN EUROPE
  • EP4553344A1 patent drawingFigure 1
  • EP4553344A1 patent drawingFigure 2
  • EP4553344A1 patent drawingFigure 3

AI summary

A one-piece recirculation part (22) intended to be housed in a cavity (24) of a threaded member (12, 14) of a ball screw mechanism (10) comprises a base (32), turned in a reference direction (200) of a reference axis (300), a recirculation path (34) turned in the opposite direction and intended to pass through a thread (26) of the threaded member (12, 14), and at least one deflector (48), projecting from the recirculation path (34) in the opposite direction to the reference direction (200). The deflector (48) forms a guide face (50) located at a distance from the recirculation path (34) and turned in the reference direction (200), opposite a light (52) in the one-piece part (22) which extends parallel to the reference axis (300) and opens onto the bottom (32) and onto the recirculation path (34).In orthogonal projection onto a reference plane (400) perpendicular to the reference axis (300), the first light (52) surrounds or merges with the guiding face (50) of the first deflector (48).