Radial Forging With Coaxial Torque Motor for Core Recrystallization

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Solution Overview

Problem

Existing forging technologies face challenges in uniformly deforming cast forging blocks to prevent crack formation in the surface area while achieving sufficient recrystallization in the core area, particularly with large bite ratios.

Innovation Solution

A forging device with a torque motor-driven eccentric shaft and hydraulic cylinders, allowing for controlled deformation through radial forging with high stroke frequency and low stroke length, combined with hydraulic actuation for uniform deformation and recrystallization, minimizing local load variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a large bite ratio is used to achieve sufficient core forming and pore reduction, then the structural improvement of the forging block is improved, but significant differences in deformation degree arise over the pressed length, leading to crack formation in the surface area

Engineering Contradiction:
Improvestructural uniformityVSAvoidcrack formation
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The forging process is segmented into multiple passes with decreasing bite ratios. The first pass uses a large bite ratio for core forming, followed by subsequent passes with progressively smaller bite ratios to uniformly deform the surface areas, thereby preventing crack formation while achieving structural improvement

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first forging pass performs preliminary core forming with a large bite ratio to address the central pore reduction requirement. Subsequent passes then address the surface deformation uniformity issue, effectively separating the core forming function from the surface finishing function across multiple sequential operations

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If a small bite ratio is used to avoid surface cracking, then crack formation is reduced, but core forming and pore reduction in the forging block become insufficient

Engineering Contradiction:
Improvecrack formationVSAvoidcore structure quality
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The forging process is divided into multiple passes where the first pass uses a large bite ratio for core forming and subsequent passes use smaller bite ratios for surface deformation. This segmentation allows each pass to specialize in one function, ensuring both core quality and surface integrity are achieved

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The forging process employs periodic action through multiple sequential passes with varying bite ratios. The bite ratio is periodically reduced across passes, allowing the system to alternately focus on core forming and surface deformation, thereby achieving both objectives over time

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If the outer punch part is decoupled from the eccentric drive to enable press forging with high bite ratio, then core forming is improved, but the device complexity increases due to additional decoupling mechanisms

Engineering Contradiction:
Improvecore forming capabilityVSAvoiddrive train complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The drive system is designed to be dynamic, allowing the outer punch part to be selectively coupled or decoupled from the eccentric drive based on the required forging mode. This dynamic reconfiguration enables the system to switch between radial forging and press forging operations without requiring separate dedicated systems for each mode

Inventive Principle:
Principle #15Dynamics

4Object-affected harmful factors

If radial forging with high stroke frequency and small bite ratio is used, then surface deformation uniformity is improved, but core forming and pore reduction become insufficient

Engineering Contradiction:
Improvesurface deformation uniformityVSAvoidcore structure quality
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The forging process is segmented into passes with different bite ratio characteristics. Early passes use larger bite ratios for core forming while later passes use smaller bite ratios for surface deformation uniformity, with the sequence optimized to achieve both core quality and surface integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Core forming is performed as a preliminary action in the first pass with a large bite ratio, establishing the necessary structural improvement in the forging block core. Subsequent passes then focus on achieving uniform surface deformation, effectively sequencing operations to address different requirements at appropriate times

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

Ensures uniform deformation and recrystallization across the pressed length of the forging saddle, preventing crack formation in the surface area and enabling effective structural improvement down to the core of the forging block.

Implementation Method 1

the inner punch part, which holds a forging tool, is drive-connected to the outer punch part by a hydraulic cylinder

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

a torque motor designed as an internal rotor, coaxial with the eccentric shaft, is provided as the electric motor

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

an eccentric drive which can drive the outer die part and whose eccentric shaft is connected to an electric motor via a coupling

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP4414099B1Forging apparatus
Publication Date: 2025.09.10 GFM GMBH
  • EP4414099B1 patent drawingFigure 1~2
  • EP4414099B1 patent drawingFigure 3

AI summary

A forging device for hot forming a cast forging block (1) is described, comprising radially guided forging dies (5), each having two die parts (7, 8) that can be displaced radially relative to each other, the inner die part (7) carrying a forging tool (2) being connected to the other outer die part (8) by means of a hydraulic cylinder (9), an eccentric drive (14) which drives the outer die part (8), the eccentric shaft (15) of which is connected to an electric motor via a coupling (23), and a pump (28) driven by the electric motor for supplying pressure to the hydraulic cylinder (9) between the inner and outer die parts (7, 8).In order to create advantageous design conditions, it is proposed that an electric motor be a torque motor (19) designed as an internal rotor, coaxial to the eccentric shaft (15), the rotor (20) of which is rotatably mounted on the eccentric shaft (15) or an eccentric shaft extension (21) following a drive flange (22) of the eccentric shaft (15), and that the coupling (23) is arranged between the rotor (20) and the drive flange (22).