Flow-Formed Electric Drive Housing with Integrated Tabs

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Solution Overview

Problem

Existing methods for producing housings for electric drives, such as casting and forging, are costly and result in components with limited strength under oscillating loads, leading to increased weight and potential fastening issues.

Innovation Solution

A housing produced by non-cutting forming from a tubular workpiece using a flow-forming machine, where the drum-shaped peripheral wall and radially projecting fastening lugs are formed in one piece through material displacement, and the base is attached via welding, achieving a stable connection and reduced weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If casting is used to produce the housing, then the production cost is high due to energy consumption and post-processing, but the structural strength is limited under oscillating loads

Engineering Contradiction:
Improvestructural strengthVSAvoidproduction cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces the thermal casting process with a mechanical flow-forming process. A tubular workpiece is radially expanded and axially elongated through flow-forming to create the housing shape, eliminating the need for melting metal and subsequent post-processing operations. This mechanical approach produces a stronger structure with continuous grain flow while reducing energy consumption and manufacturing costs.

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

2Strength

If material thickness is increased to improve strength under oscillating loads, then the structural strength improves, but the weight of the housing increases

Engineering Contradiction:
Improvestrength under oscillating loadsVSAvoidhousing weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent changes the material parameters through flow-forming, which work-hardens the metal and refines the grain structure. This process increases the yield strength and fatigue resistance of the material, allowing the housing to withstand oscillating loads with thinner walls. The continuous grain flow pattern created during flow-forming further enhances strength without requiring increased material thickness.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If cutting is used to form the fastening lugs, then the manufacturing process is simpler, but the connection stability between the peripheral wall and fastening lugs is reduced

Engineering Contradiction:
Improveconnection stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent maintains continuous material flow during the forming process. The fastening lugs are formed by displacing material radially outward during flow-forming, creating a continuous grain structure that extends from the peripheral wall into the lugs. This continuous material flow eliminates weak points that would result from cutting or separate attachment, ensuring superior connection stability while integrating the lug formation into the main shaping process.

Inventive Principle:
Principle #20Continuity of useful 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

This method results in a cost-effective, high-strength housing with improved connection stability and reduced weight, addressing the limitations of traditional production methods.

Implementation Method 1

material of the tubular workpiece being displaced radially outwards. This radially outwardly displaced material is used to form the attachment tabs

Methodology Applied
Scientific EffectMaterial displacement: Plasticity

Implementation Method 2

the base is attached, in particular welded, to the drum-shaped peripheral wall

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3379700B1Housing and method for producing same
Publication Date: 2020.04.29 FISCHER & KAUFMANN GMBH & CO KG
  • EP3379700B1 patent drawingFigure 1~2
  • EP3379700B1 patent drawingFigure 3~4
  • EP3379700B1 patent drawingFigure 5

AI summary

The invention relates to a housing (10), in particular for an electric drive, with a drum-shaped circumferential wall (12) and a radially extending base (14), wherein radially outwardly projecting mounting tabs (16) are arranged in the region of the base. According to the invention, the drum-shaped circumferential wall and the radially outwardly projecting mounting tabs are formed in one piece from a tubular workpiece, wherein the mounting tabs are formed without machining by material displacement from the material of the tubular workpiece. The invention also includes a method for manufacturing the housing.