Open-Nut Ball Screw Assembly for Holder-Passing Support Stability

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Solution Overview

Problem

Conventional ball screw assemblies with complete cylinder nuts face issues of sagging and deflection due to supporting holder mechanisms, leading to manufacturing precision problems and improper ball rolling, especially when the nut passes the supporting holder area.

Innovation Solution

A ball screw assembly with an open nut featuring an axial opening, modular configuration of open shields, first and second circulators, and ball circulating assemblies, which allows the nut to pass through supporting holders without interference, eliminating the need for resilient mechanisms and ensuring continuous support and precise operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a complete cylinder ball nut is used with a supporting holder, then the screw can be supported to prevent sagging, but the ball nut cannot pass the supporting holder area smoothly causing deflection and improper ball rolling

Engineering Contradiction:

Improvescrew support stabilityVSAvoidball nut passage smoothness

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The ball nut is segmented with an axial opening that divides the cylindrical structure into two separate axial walls. This segmentation allows the ball nut to pass through the supporting holder area without interference, as the opening provides clearance for the supporting holder to remain in place while the nut moves past it.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The axial opening creates a new dimensional pathway through the ball nut structure. Instead of the nut having to move the supporting holder out of the way (radial dimension), the opening allows the supporting holder to remain in its supporting position while the nut passes through axially, resolving the spatial conflict.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of operation

If a resilient mechanism is added to the supporting holder to move it away from the screw, then the ball nut can pass, but the screw may sag when the holder is away causing deflection

Engineering Contradiction:

Improveball nut passage capabilityVSAvoidscrew deflection control

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The resilient mechanism and its associated movement function are extracted from the supporting holder system. The supporting holder is designed to remain fixed in its supporting position without any movement mechanism, while the axial opening in the ball nut provides the passage capability that previously required the holder to move away.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The axial opening in the ball nut self-provides the passage capability needed to clear the supporting holder area. The opening structure itself enables the nut to pass through without requiring external resilient mechanisms or active movement of the supporting holder, maintaining both support stability and passage capability.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If the supporting holder is temporarily moved away from the screw, then the ball nut can pass, but the screw sags due to its weight causing deflection

Engineering Contradiction:

Improveball nut passageVSAvoidscrew positional stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

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 design enhances manufacturing precision by preventing sagging and deformation of the guider, ensuring smooth ball rolling and providing a dustproof function, while allowing for flexible configuration based on load requirements.

Implementation Method 1

The ball screw assembly comprises a guider, an open nut, a plurality of open shields, a first circulator, a second circulator, and a plurality of ball circulating assemblies... The inner spiral channels and the spiral channels form a plurality of inner ball races... Each of the outer ball races is perpendicular to the central axis... One of the first ball circulating assemblies rolls in the first ball circulating race, and another one of the ball circulating assemblies rolls in the second ball circulating race

Methodology Applied

Scientific EffectRolling motion: Ball Bearing

Data Source

PatentEP3828440B1Ball screw assembly

Publication Date: 2022.11.23 LEE SZU YING

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AI summary

A ball screw assembly includes a guider (10), an open nut (20), open shields (30, 30a), a first circulator (40, 40a), a second circulator (50, 50a), and ball circulating assemblies (60, 60a). The open nut (20) is slidably fitted over the guider (10) and includes an axial cylinder (21) having an axial opening (211). Inner spiral channels (2141) of the axial cylinder (21) and spiral channels (11) of the guider (10) form inner ball races. The open shields are coaxially fitted over the axial cylinder. An inner peripheral wall of each of the open shields (30, 30a) and an outer annular wall (215) of the axial cylinder (21) form an outer ball race. The first circulator (40, 40a) and the second circulator (50, 50a) are disposed on the axial cylinder (21) corresponding to the open shields (30, 30a). The inner ball races, first curves (41, 41a) of the first circulator (40, 40a), the outer ball races, and second curves (51, 51a) of the second circulator (50, 50a) form ball circulating races, and the ball circulating assemblies (60, 60a) roll in the ball circulating races.