Compressor Impeller Fixing Nut Curved Surface Air Flow

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Solution Overview

Problem

The existing supercharger configurations, which use a seal cap to stabilize air flow into the compressor impeller, increase complexity and assembly steps, leading to higher production and maintenance costs and energy loss.

Innovation Solution

A compressor-impeller fixing nut with a curved-surface shaped portion that guides air flow smoothly along its outer peripheral surface, reducing the need for a seal cap and simplifying the assembly configuration, while satisfying specific geometric conditions to minimize energy loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a seal cap is attached to the tip of the shaft to stabilize air flow, then air flow stability is improved, but device complexity increases and assembly steps increase

Engineering Contradiction:
Improveair flow stabilityVSAvoidassembly complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent integrates the air flow stabilization function directly into the fixing nut by adding a curved-surface shaped portion to its outer peripheral surface. This merging of functions eliminates the need for a separate seal cap component, thereby reducing device complexity and assembly steps while maintaining air flow stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fixing nut is designed to perform multiple functions: it not only secures the compressor impeller to the shaft but also stabilizes the air flow through its curved-surface shaped portion. This multi-functionality eliminates the need for dedicated air flow stabilization components, reducing overall assembly complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Stability of the object's composition

If a seal cap is attached to the tip of the shaft, then air flow stability is improved, but production cost and maintenance cost increase

Engineering Contradiction:
Improveair flow stabilityVSAvoidproduction cost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

By combining the air flow stabilization function into the fixing nut through the curved-surface shaped portion, the patent reduces the total number of components that need to be manufactured and assembled. This integration lowers production costs by eliminating the seal cap manufacturing process and reducing assembly operations.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If the curved-surface shaped portion has a protruding outer peripheral surface, then air flow guidance is improved, but the nut dimensions increase

Engineering Contradiction:
Improveair flow efficiencyVSAvoidnut axial length
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The curved-surface shaped portion is designed with specific geometric characteristics (protruding outer peripheral surface with controlled curvature) localized to the region where air flow guidance is most needed. This local optimization improves air flow efficiency without requiring a uniform increase in the entire nut dimensions.

Inventive Principle:
Principle #3Local quality

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 solution reduces energy loss and maintains high supercharging efficiency without increasing the complexity of the compressor impeller assembly, thereby lowering production and maintenance costs.

Implementation Method 1

the air flowing along the axial direction to the compressor-impeller fixing nut flows along the outer peripheral surface of the curved-surface shaped portion from the first end side of the compressor-impeller fixing nut

Methodology Applied
Scientific EffectFluid flow guidance:

Data Source

PatentEP3421751B1Compressor impeller fixing nut, impeller assembly, and supercharger
Publication Date: 2020.07.22 MITSUBISHI HEAVY IND MARINE MASCH & EQUIP CO LTD
  • EP3421751B1 patent drawingFigure 1
  • EP3421751B1 patent drawingFigure 2
  • EP3421751B1 patent drawingFigure 3

AI summary

A compressor-impeller fixing nut has a tubular shape, and includes: a curved-surface shaped portion disposed in a first range from a first end side in an axial direction, the curved-surface shaped portion having an outer diameter which increases toward a second end side in the axial direction and including an outer peripheral surface having a curved shape which protrudes outward in a radial direction in a cross section along the axial direction; and a nut portion disposed in a second range closer to the second end side from the first range in the axial direction, the nut portion having an outer peripheral surface with a nut shape. An expression (Dlmax-Dlmin)/2<L is satisfied, where L is a length of the first range in the axial direction, and D1max is a maximum value and D1min is a minimum value of the outer diameter of the curved-surface shaped portion in the first range.