Turbocharger Impeller-to-Shaft Joining Without Axial Nut Load

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Solution Overview

Problem

The existing configuration of turbochargers, where a compressor impeller is fixed to a shaft using a nut, faces difficulties in managing axial force, making it challenging to manufacture rotating bodies and turbochargers efficiently.

Innovation Solution

A rotating body design featuring a compressor impeller with an insertion hole and a boss portion that is welded to the shaft using electromagnetic forming, allowing for easier assembly and reduced axial force management, along with a manufacturing method that includes inserting the shaft through the compressor impeller's insertion hole and joining the boss portion to the shaft via electromagnetic forming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a compressor impeller is fixed to a shaft using a nut with axial force, then the impeller can be securely attached, but it becomes difficult to manage axial force and increases manufacturing complexity

Engineering Contradiction:

Improveattachment strengthVSAvoidmanufacturing ease

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical nut-and-thread fastening system with electromagnetic forming technology. The boss portion of the impeller is magnetically pressed against the shaft during electromagnetic forming, eliminating the need for nuts and axial force management while achieving secure attachment. This substitution of mechanical fastening with electromagnetic joining directly resolves the contradiction by simplifying manufacturing while maintaining attachment strength.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If a nut is used to fix the compressor impeller to the shaft, then the impeller can be secured, but the device complexity increases due to additional components

Engineering Contradiction:

Improveattachment strengthVSAvoidassembly complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent extracts and removes the nut component from the assembly system. By using electromagnetic forming to directly join the boss portion to the shaft, the design eliminates the need for separate fastening components like nuts. This extraction of unnecessary components directly reduces device complexity while maintaining the functional requirement of secure impeller attachment.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the attachment function directly into the impeller structure itself. The boss portion, which is already part of the impeller body, serves as both the structural support and the joining interface with the shaft. This merging of functions eliminates separate fastening components and simplifies the overall assembly structure.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If electromagnetic forming is used to join the boss portion to the shaft, then manufacturing is simplified and axial force management is reduced, but new manufacturing technology requirements are introduced

Engineering Contradiction:

Improvemanufacturing easeVSAvoidtechnology adaptability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the fundamental parameter of the joining process from mechanical (axial force through nuts) to electromagnetic (magnetic pressure during forming). This parameter change enables the use of electromagnetic forming technology, which simplifies manufacturing by eliminating complex axial force management while achieving reliable joins between the boss portion and shaft.

Inventive Principle:

Principle #35Parameter changes

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 design simplifies the manufacturing process, reduces axial force variation, and allows for higher speed capabilities while providing increased design freedom and improved operability by securely welding the boss portion to the shaft in the radial direction.

Implementation Method 1

joining a boss portion, which is formed at one end of the main body, and the shaft by electromagnetic forming

Methodology Applied

Scientific EffectElectromagnetic forming: Electromagnetic Propulsion

Data Source

PatentUS11530706B2Rotating body, turbocharger, and rotating body manufacturing method

Publication Date: 2022.12.20 IHI CORP

AI summary

Provided is a rotating body, including: a shaft; and a compressor impeller including: a main body having an insertion hole, which extends from one end to another end side and is configured to receive the shaft inserted therethrough; a boss portion formed at one end side of the main body; and a joint portion, which is formed on an inner peripheral surface of the insertion hole at the boss portion and is welded to the shaft.