Ball Screw Nut Laminate Die Structure for Low-Cost Hydraulic Forming

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Solution Overview

Problem

The hydraulic forming method for manufacturing machine components, such as ball screw devices, is costly due to the complexity of forming dies required for precise shapes, especially for components with intricate designs, leading to increased manufacturing costs.

Innovation Solution

A ball screw device is manufactured using a forming die with a laminate body composed of laminated plates, which are used to deform the process material hydraulically, allowing for cost-effective production by reducing the complexity and cost of the forming die, while maintaining the accuracy of the component's shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a forming die with complex structure is used to manufacture components with intricate shapes, then the manufacturing precision and shape accuracy are improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveshape accuracyVSAvoidforming die structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The forming die is divided into a laminate body composed of multiple plates (first plate, second plate, third plate, fourth plate) that can be assembled and disassembled. This segmentation allows the complex forming die to be constructed from simpler individual plate components, reducing the overall device complexity while maintaining the ability to form intricate shapes through the combined action of multiple plates with different surface features

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The laminate body structure nests multiple plates within each other, where the first and second plates form an outer frame structure, and the third and fourth plates are positioned inside to form the inner peripheral surface. This nested arrangement allows complex three-dimensional forming surfaces to be created through the combination of simpler two-dimensional plate components

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If expensive materials are used for the forming die to ensure durability, then the reliability is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveforming die durabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Different plates in the laminate body are assigned different functions and material requirements. The third and fourth plates that form the inner peripheral surface require high durability for hydraulic forming, while the first and second plates forming the outer frame can use less expensive materials. This local differentiation of material quality allows the overall manufacturing cost to be reduced while maintaining reliability where it is most needed

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The forming die uses a composite structure combining multiple plates that can be made from different materials. This allows the selection of cost-effective material combinations that provide the necessary durability for hydraulic forming operations without requiring expensive materials throughout the entire forming die structure

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If a laminate body with multiple plates is used for the forming die, then the manufacturing cost is reduced, but the structural complexity increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidlaminate body structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The laminate body structure serves multiple functions simultaneously: the first and second plates provide the outer frame structure and support, while the third and fourth plates create the inner peripheral forming surface. This multi-functionality allows a single laminate body assembly to replace what would traditionally require multiple separate forming die components, reducing overall device complexity despite the presence of multiple plates

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

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 reduces the manufacturing cost of ball screw devices and other machine components by simplifying the forming die structure and using less expensive materials for the laminate body, while maintaining the durability and accuracy needed for the components.

Implementation Method 1

a hydraulic pressing mechanism (300), and a controller (400). The forming mechanism (200) includes a hydraulic pressing mechanism (300)... plastically deforming the tubular material (108) radially outward until the tubular material has a shape along the forming peripheral surface (113)

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

plastically deforming the tubular material (108) radially outward until the tubular material has a shape along the forming peripheral surface (113)

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3984664B1Ball screw device, mechanical component manufacturing method, mechanical device manufacturing method, vehicle manufacturing method, mechanical component, mechanical device, vehicle, hydraulic forming method, and forming die for hydraulic forming
Publication Date: 2023.07.19 NSK LTD
  • EP3984664B1 patent drawingFigure 1
  • EP3984664B1 patent drawingFigure 2
  • EP3984664B1 patent drawingFigure 3

AI summary

A ball screw device includes a nut (3), a screw shaft, and a plurality of balls arranged between the nut (3) and the screw shaft. The nut (3) includes a first member (11) disposed to surround the screw shaft, a second member (10) disposed between the screw shaft and the first member (11), and a third member (12) disposed between the first member (11) and the second member (10). The third member (12) includes a laminate body (12A) having a plurality of plates (22a, 22b) laminated in an axial direction. The laminate body (12A) includes an inner surface facing an outer surface of the second member (10). The inner surface of the laminate body (12A) has a shape corresponding to a shape of the outer surface of the second member (10).