Mandrel Support Shaft Design for Precise Ring Rolling

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Solution Overview

Problem

Existing methods for manufacturing ring-shaped members, such as bearing rings, face challenges in preventing mandrel damage and ensuring precision due to variations in metal blank volume, leading to potential distortion and increased internal stress.

Innovation Solution

A manufacturing apparatus that includes a mandrel, an outer-diameter constraining die, and an excess material release mechanism, allowing the mandrel to displace and expand the molding space to release excess material, reducing internal stress and preventing mandrel damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional rolling process is performed on metal blanks with varying volumes, then the manufacturing process can be completed, but internal stress increases and distortion occurs leading to mandrel damage

Engineering Contradiction:
Improvemandrel durabilityVSAvoidring-shaped member precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The mandrel is designed with movable support shaft sections that can dynamically adjust their position in the axial direction. When excess material is detected during the rolling process, the support shaft sections move to accommodate the additional material volume, preventing internal stress buildup and distortion while maintaining mandrel integrity and manufacturing precision

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system automatically detects excess material through pressing force sensors and self-adjusts the mandrel configuration by moving the support shaft sections. This self-service mechanism eliminates the need for external intervention or complex control systems, while effectively preventing mandrel damage and maintaining precision

Inventive Principle:
Principle #25Self-service

2Device complexity

If the molding space is kept fixed during processing, then the apparatus structure is simple, but excess material causes increased internal stress and potential mandrel damage

Engineering Contradiction:
Improveapparatus structureVSAvoidmandrel durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The mandrel incorporates movable support shaft sections that can adjust their axial position during processing. This dynamic configuration allows the molding space to adapt to variations in metal blank volume without requiring a completely redesign of the apparatus structure, maintaining relative simplicity while preventing mandrel damage

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The support shaft sections are nested within the mandrel structure, with the rolling shaft section positioned between the support shaft sections. This nested arrangement allows the support shaft sections to move independently to accommodate excess material while maintaining the overall compact and simple apparatus structure

Inventive Principle:
Principle #7Nested doll (Nesting)

3Productivity

If excess material is not released during processing, then the processing is efficient, but distortion occurs and manufacturing precision deteriorates

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidring-shaped member precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system uses pressing force sensors to detect excess material during the rolling process and provides real-time feedback. When excess material is detected, the control system activates the movable support shaft sections to expand the molding space, allowing excess material to be released. This feedback mechanism maintains processing efficiency while preventing distortion and preserving manufacturing precision

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system automatically detects and responds to excess material conditions through the pressing force sensors and movable support shaft sections. This self-service approach allows the system to maintain optimal processing conditions without external intervention, preserving both productivity and manufacturing precision

Inventive Principle:
Principle #25Self-service

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

The solution effectively prevents mandrel damage and improves the precision of ring-shaped members by reducing internal stress and preventing distortion, even with varying metal blank volumes.

Implementation Method 1

an excess material release means which is capable of expanding a molding space by displacing in the axial direction when a pressing force having a specified size or more is received in the axial direction from the metal blank during processing of the metal blank

Methodology Applied
Scientific EffectDisplacement: Displacement

Implementation Method 2

when a pressing force having a specified size or more is received in the axial direction from the metal blank during processing of the metal blank

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3184192B1Method of manufacturing ring-like member and manufacturing apparatus for same
Publication Date: 2021.05.12 NSK LTD
  • EP3184192B1 patent drawingFigure 1
  • EP3184192B1 patent drawingFigure 2~3
  • EP3184192B1 patent drawingFigure 4

AI summary

Construction is achieved that, together with preventing the occurrence of damage to a mandrel, is able to improve precision of the shape of a ring-shaped member after processing. A mandrel 23a includes a pair of support shaft sections 37a, 37b that are provided so as to be separated in the axial direction and so as to be concentric with each other, and a rolling shaft section 38 that is concentrically provided in the axial direction between the pair of support shaft sections 37a, 37b. One of the support shaft sections 37a is provided in a state in which displacement in the axial direction with respect to the rolling shaft section 38 is regulated. The other support shaft section 37b is provided in a state in which displacement in a direction going away from the rolling shaft section 38 is possible when a pressing force is applied in that direction.