Ball Screw End Deflector Rib Reinforcement

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Solution Overview

Problem

Conventional ball screws experience positional precision impairment due to axial force from screw fastening, which deforms the end deflector and affects the smooth operation, especially when the deflector is made of plastic material.

Innovation Solution

The ball screw design includes a flange with a rib that supports the fastening force and enhances bending stiffness, minimizing deformation and maintaining positional precision, with the rib extending inward from the flange's radially inner edge and forming a closed loop to reinforce the flange and main part, preventing deformation and maintaining precision without increasing the nut's axial length or diameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If screws are used to secure the end deflector to the nut main body, then the end deflector is fixedly secured to the nut main body, but the axial force from the screws causes deformation of the end deflector impairing positional precision

Engineering Contradiction:

Improvefixing stabilityVSAvoidpositional precision

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The end deflector is segmented into a main body and a flange portion, where the flange serves as a dedicated fastening structure that separates the loading function from the positioning function, preventing deformation of the positioning-critical main body

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flange portion is designed with different properties than the main body - it is specifically structured to bear axial loads through its thickness and rib reinforcements, while the main body maintains its dimensional stability for positioning precision

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the end deflector is made of plastic material, then the deflector can be manufactured with complex shapes and is lighter, but it is more prone to deformation under axial force

Engineering Contradiction:

ImprovemanufacturabilityVSAvoidresistance to deformation

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The flange is designed as a thin-walled structure with strategic rib reinforcements that provide high stiffness-to-weight ratio, allowing plastic material to achieve sufficient structural strength while maintaining manufacturability through molding

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The rib structures incorporate curved surfaces that efficiently distribute axial loads around the flange perimeter, preventing stress concentration and deformation in the plastic material

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS10648546B2Ball screw

Publication Date: 2020.05.12 KURODA PRECISION INDS

AI summary

To prevent the positional precision of the ball return passage and the tongue of the end deflector relative to the nut main body from being impaired by an axial force applied by a screw used for securing the end deflector to the nut main body, the end deflector includes a flange (32) provided at an axial end of a main part (30) of the end deflector and provided with an axial through hole (50) for receiving a screw which is threaded into the nut main body, and a rib (52) projecting from a radially inner edge of the flange to an inner side of the deflector receiving recess (26).