Drawn Axle Housing Tube Forming for Thin Walls Without Welding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional tubes used for housing axle shafts in vehicles have varying wall thicknesses, require welding of separate components, and lack efficiency in weight reduction while maintaining yield strength, which hinders fuel efficiency and manufacturing efficiency.

Innovation Solution

A method of manufacturing a drawn tube with a hollow interior using a multi-step die assembly process that involves forming a billet into a pre-formed billet, then an extruded tube, and finally a drawn tube with a reduced wall thickness of 3 to 18 millimeters, achieving a yield strength of at least 750 MPa without the need for welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional tubes are made by welding separate components (tube portion and spindle end), then the tube can be assembled, but the manufacturing time and expense increase

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidmanufacturing time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent merges the tube portion and spindle end into a single integrated tube structure formed by one continuous extrusion process. The extrusion die is designed with multiple cavities that form different sections of the tube in one operation, eliminating the need to manufacture and weld separate components together.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The extrusion die is segmented into multiple cavities (first cavity for tube portion, second cavity for spindle end) that form different sections of the tube simultaneously. This segmentation allows complex multi-section tubes to be produced in a single extrusion operation without requiring multiple welding steps.

Inventive Principle:
Principle #1Segmentation

2Weight of moving object

If conventional tubes use separate components that are welded together, then the tube can be constructed, but the weight increases and fuel efficiency decreases

Engineering Contradiction:
Improvetube weightVSAvoidmanufacturing complexity
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent combines multiple tube sections into a single monolithic structure produced by continuous extrusion. This eliminates the need for welding separate components, reducing overall weight while simplifying the manufacturing process to a single operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses different alloy compositions in different sections of the tube (as defined by the multi-cavity extrusion die) to optimize weight and strength characteristics for each specific section, allowing weight reduction without compromising overall structural integrity.

Inventive Principle:
Principle #35Parameter changes

3Strength

If conventional tubes are made with sufficient wall thickness to ensure yield strength, then the tube can avoid failure, but the weight increases

Engineering Contradiction:
Improveyield strengthVSAvoidtube weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies different material properties (alloy compositions) to different sections of the tube based on their specific functional requirements. High-strength alloys are used in sections requiring maximum strength, while lighter alloys are used in sections where lower strength is acceptable, optimizing the overall strength-to-weight ratio.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a composite tube structure with multiple alloy compositions within a single extruded component. Each alloy section is strategically placed to provide the necessary strength characteristics for its specific location, reducing overall weight while maintaining required yield strength throughout the tube.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If conventional tubes require welding of separate components, then the tube can be assembled, but manufacturing expense increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidmanufacturing process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent consolidates the manufacturing of multiple tube sections into a single extrusion process using a multi-cavity die. This eliminates the need for separate manufacturing operations and welding processes, reducing both manufacturing cost and process complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The extrusion die is segmented into multiple cavities that form different tube sections in one operation. This segmentation enables complex multi-section tubes to be produced through a single, simplified process rather than requiring multiple manufacturing steps and assembly operations.

Inventive Principle:
Principle #1Segmentation

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 results in a lighter tube with increased yield strength, reducing manufacturing time and costs by eliminating the need for welding and allowing for a single-piece construction, thereby enhancing fuel efficiency and manufacturing efficiency.

Implementation Method 1

pressing the billet into the cavity of the first die to form a bore at one end of the billet thereby producing a pre-formed billet

Methodology Applied
Scientific EffectPlasticity: Plasticity

Implementation Method 2

pressing the pre-formed billet into the cavity of the second die assembly to elongate the pre-formed billet and form a hollow interior therein thereby producing an extruded tube

Methodology Applied
Scientific EffectExtrusion: Extrusion

Implementation Method 3

pressing the extruded tube into the cavity of the third die assembly to further elongate the extruded tube and decrease the thickness of the wall of the extruded tube

Methodology Applied
Scientific EffectDrawing:

Data Source

PatentEP3804872B1Method of manufacturing a tube
Publication Date: 2023.05.17 AMERICAN AXLE & MANUFACTURING INC
  • EP3804872B1 patent drawingFigure 1~3D
  • EP3804872B1 patent drawingFigure 4A~5B
  • EP3804872B1 patent drawingFigure 6

AI summary

A method is used to manufacture a drawn tube having a hollow interior for housing an axle shaft. The method includes the steps of placing a billet into a first die assembly and pressing the billet into the first die to producing a pre-formed billet. The method also includes the steps of moving the pre-formed billet from the first die assembly to a second die assembly and pressing the pre-formed billet into the second die assembly to produce an extruded tube. The method further includes the steps of moving the extruded tube from the second die assembly to a third die assembly and pressing the extruded tube into the third die assembly to further elongate the extruded tube and decrease the thickness of the wall of the extruded tube to of from about 3 to about 18 millimeters to produce the drawn tube having the yield strength of at least 750 MPa.