Toothed Disc Cold Forming With Indexed Multi-Stage Rollers

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Solution Overview

Problem

Existing methods for cold forming toothed discs face challenges in achieving tight tolerances while being time-consuming and costly, particularly due to the need for multiple operations like rotation with a tooth forming device and subsequent hobbing.

Innovation Solution

The method involves performing the first and second tooth forming operations in two separate forming stations, with the disc blank being indexed for alignment and rotational orientation to ensure precise formation of teeth, allowing for simultaneous or incremental formation of teeth by different sets of tooth forming rollers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If cold press forming is used to form teeth, then manufacturing time is reduced, but manufacturing precision deteriorates

Engineering Contradiction:
Improvemanufacturing timeVSAvoidtooth shape tolerance
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The tooth forming process is divided into multiple sequential stages: first forming operation with first rollers, indexing operation, and second forming operation with second rollers. This segmentation allows each stage to contribute to the final tooth profile, achieving both efficiency and precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first tooth forming operation performs preliminary shaping of the teeth before the final forming operation. This preliminary action prepares the workpiece for the subsequent precision forming, enabling tight tolerances to be achieved in the final operation while maintaining overall process efficiency.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If hobbing operation is used to form teeth, then manufacturing precision is improved, but productivity deteriorates

Engineering Contradiction:
Improvetooth shape toleranceVSAvoidmanufacturing time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The traditional hobbing operation is replaced with a cold forming process using tooth forming rollers. This substitution eliminates the need for material removal while achieving tight tolerances through controlled plastic deformation, significantly reducing manufacturing time while maintaining precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The first tooth forming operation performs preliminary shaping of the teeth before the final forming operation. This preliminary action prepares the workpiece for the subsequent precision forming, enabling tight tolerances to be achieved in the final operation while maintaining overall process efficiency.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If multiple forming operations are performed, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvetooth shape toleranceVSAvoidnumber of forming stations
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The indexing mechanism serves multiple functions: it repositions the disc blank between forming operations, ensures precise alignment for the second forming operation, and enables the sequential processing of multiple workpieces. This multi-functionality reduces the need for separate specialized devices for each operation.

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 enables the production of toothed discs with high tolerance and reduced manufacturing time and cost, as the teeth are formed efficiently in multiple stages with precise alignment and orientation.

Implementation Method 1

a method of cold forming a toothed disc

Methodology Applied
Scientific EffectCold forming: Cold-forming

Implementation Method 2

the rollers force the disc blank through the tooth forming rollers and cold form teeth in the annular thickened ring

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP2125266B1Method for manufacturing a toothed disc
Publication Date: 2021.06.02 MAGNA POWERTRAIN INC(CA)
  • EP2125266B1 patent drawingFigure 1~2
  • EP2125266B1 patent drawingFigure 3
  • EP2125266B1 patent drawingFigure 4

AI summary

A novel method of manufacturing a toothed disc is taught wherein the teeth can be cold formed to a relatively high set of tolerances in a relatively time-efficient manner. A cold-formed disc blank with an annular thickened ring about its periphery is forced through a set of tooth forming rollers which engage the annular thickened ring. As the blank is forced through the set of rollers, the rollers cold forming tooth structures in the annular ring. In some circumstances, the tooth structure can be a final desired tooth profile and in other circumstances, the disc blank may be forced through two or more different sets of tooth forming rollers, each set of tooth forming rollers contributing to the forming of the final, desired tooth profile.