Tooth-Shaped Component Forging With Corner Thickening

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Solution Overview

Problem

The manufacturing of tooth-shaped components through cold forging often results in superposition defects, which reduce yield and hinder the achievement of high dimensional accuracy and strength, despite the method's potential for low costs and high-quality components.

Innovation Solution

A method involving a drawing process to form a cylindrical container with specific radius ratios, followed by a diameter-reducing process to increase corner thickness, and a tooth shape-forming process, ensuring the corner portion's external shape satisfies certain thickness conditions to prevent superposition defects, thereby improving yield and quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If cold forging is used to manufacture tooth-shaped components, then manufacturing cost is reduced and productivity is improved, but superposition defects occur which reduce yield and manufacturing precision

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoiddimensional accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention applies preliminary action by performing a diameter-reducing process on the cylindrical container before the tooth shape forming process. This preliminary reduction of diameter at the corner portion prevents material superposition during subsequent forming operations, thereby eliminating superposition defects while maintaining the efficiency of cold forging

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention applies local quality by selectively reducing the diameter only at the corner portion of the cylindrical container, rather than uniformly throughout. This localized modification increases thickness specifically where superposition defects occur, preventing defects without unnecessarily altering other areas of the component

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If conventional drawing process is used to form cylindrical container, then manufacturing is simplified, but corner portion thickness is insufficient leading to superposition defects

Engineering Contradiction:
Improveprocess simplicityVSAvoidcorner thickness uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention applies segmentation by dividing the forming process into distinct stages: a conventional drawing process to form the cylindrical container, followed by a separate diameter-reducing process for the corner portion, and finally a tooth shape forming process. This segmentation allows each process to be optimized independently, maintaining overall simplicity while achieving precise corner thickness control

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The diameter-reducing process is performed as a preliminary action before tooth shape forming, specifically increasing corner portion thickness to prevent superposition defects during the subsequent tooth forming operation

Inventive Principle:
Principle #10Preliminary action

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 method effectively reduces superposition defects, enhances the yield of tooth-shaped components, and achieves high dimensional accuracy in thickness without drafts, resulting in high-quality components with improved manufacturing efficiency.

Implementation Method 1

diameter-reducing process of reducing a diameter of a particular part in which a tooth tip portion is to be formed in the side surface portion of the cylindrical container, so as to increase a thickness of a corner portion

Methodology Applied
Scientific EffectPlasticity: Plasticity

Implementation Method 2

tooth shape-forming process of forming the tooth tip portion in the particular part of the cylindrical container reduced in diameter

Methodology Applied
Scientific EffectPlasticity: Plasticity

Data Source

PatentEP3248705B1Method for manufacturing tooth-shaped component
Publication Date: 2021.03.03 NIPPON STEEL CORPORATION
  • EP3248705B1 patent drawingFigure 1A~1B
  • EP3248705B1 patent drawingFigure 1C~1D
  • EP3248705B1 patent drawingFigure 2A~2B

AI summary

There is provided a method of manufacturing a tooth-shaped component including drawing process of draw-forming a workpiece so as to obtain a cylindrical container which has a bottom surface portion and a side surface portion; diameter-reducing process of reducing a diameter of a particular part in which a tooth tip portion is to be formed in the side surface portion of the cylindrical container, so as to increase a thickness of a corner portion such that an external shape of the corner portion between the bottom surface portion and the side surface portion satisfies the following conditional expression (1); and tooth shape-forming process of forming the tooth tip portion in the particular part of the cylindrical container reduced in diameter in the diameter-reducing process, so as to obtain a tooth-shaped component which has the bottom surface portion, the side surface portion, and the tooth tip portion. ΔR+ΔH≤2t